Publications
July 2023
Davis OC, Price TJ (2023) Tiam1 creates a painful link between dendritic spine remodeling
and NMDA receptors. Neuron. In press.
Diaz-del Castillo M, Palasca O, Nemler T, Thygesen D, Chavez-Saldana N, Vazquez-Mora J,
Ponce Gomez L, Jensen L, Evans H, Andrews R, Mandal A, Neves D, Mehlen, P, Caruso JP,
Dougherty PM, Price TJ, Chantry A, Lawson M, Andersen T, Jimenez-Andrade JM, Heegaard
AM (2023) Metastatic infiltration of nervous tissue and periosteal nerve sprouting in multiple
myeloma induced bone pain in mice and human. Journal of Neuroscience, JN-RM-0404-23.
June 2023
Garrity R, Arora N, Haque MA, Weis D, Trinh RT, Neerukonda SV, Kumari S, Ubogo EE,
Mahalingam R, Price TJ, Kavelaars A, Heijnen CJ, Shepherd AJ (2023) Fibroblast-derived
PI16 sustains inflammatory pain via regulation of CD206+ myeloid cells. Brain, Behavior and
Immunity. 112:220-234.
Lesnak JB, Mazhar K, Price TJ. (2023) Neuroimmune mechanisms underlying post-acute
sequelae of SARS-CoV-2 (PASC) pain, predictions from a ligand-receptor interactome.
Current Rheumatology Reports. 1-13.
May 2023
Miller Neilan RC, Reith C, Anandan IUG, Kraeter K, Allen H, BJ Kolber C*. (2023). Developing a 3-D
computational model of neurons in the central amygdala to understand pharmacological targets for
pain. Frontiers in Pain Research 4. doi: 10.3389/fpain.2023.1183553
Mitchel ME, Cook LC, Shiers S, Tavares-Ferreira D, Akopian AN, Dussor G, Price TJ (2023)
Characterization of fragile X mental retardation protein (FMRP) expression in human
nociceptors and their axonal projections to the spinal dorsal horn. Journal of Comparative
Neurology. 531(7):814-835
Rodriguez-Palma EJ, De la Luz-Cuellar YE, Islas-Espinoza AM, Felix-Leyva AE, Shiers S,
Garcia G, Torres-Lopez JE, Delgado-Lezama R, Murbartian J, Price TJ, Granados-Soto V.
(2022) Activation of 6-containg GABAA receptor induces antinociception under physiological
and pathological conditions. PAIN. 164(5):948-966.
April 2023
Mason BN, Hassler SN, Boitano S, Vagner J, DeFea KA, Price TJ, Dussor G (2023) PAR2
activation in the dura causes acute behavioral response and priming to glyceryl trinitrate in a
mouse migraine model. Journal of Headache and Pain. 24(1):42
De la Pena J, Chase R, Kunder N, Smith P, Tzu-Fang L, Stanowick A, Suresh P, Shukla T,
Butcher S, Price TJ, Campbell ZT (2023) Inhibition of nonsense-mediated decay produces nociceptive sensitization through activation of the integrated stress response. Journal of
Neuroscience 43(16):2921-2933.
Shiers S, Sahn JJ, Price TJ (2023) MNK1 and MNK2 expression in the human dorsal root and
trigeminal ganglion. Neuroscience. 515. 96-107
Sankaranarayanan I, Tavares-Ferreira D, He L, Kume M, Mwirigi JM, Madsen TM, Petersen
KA, Munro G, Price TJ. (2022) Meteorin alleviated paclitaxel-induced peripheral neuropathic
pain in mice. Journal of Pain. S1526-5900(22)-0441-2.
March 2023
Ehlers VL, Sadler KE, Stucky CL (2023). Peripheral TRPV4 hypersensitivity contributes to chronic sickle
cell disease pain. Pain 164(8): 1874-1886.
Alexander, S.N., Jeong, H.S., Szabo-Pardi, T.A., Burton, M.D. Sex-specific differences in alcohol-
induced pain sensitization. Neuropharmacology. 2023 Mar 1;225:109354. doi:
10.1016/j.neuropharm.2022.109354. Epub 2022 Nov 29
Dos Santos, N.L., Lenert, M.E., Castillo, Z.W., Mody, P.H., Thompson, L.T., Burton, M.D.
Postoperative pain drives differential behavioral and neuroimmune phenotypes across age and sex.
Neurobiol Aging. 2023 Mar;123:129-144. doi: 10.1016/j.neurobiolaging.2022.09.008. Epub 2022 Nov
23
Lackovic J, Jeevakumar V, Burton MD, Price TJ, Dussor G (2023) Peroxynitrite contributes to
behavioral responses, increased trigeminal excitability, and changes in mitochondrial function
in a preclinical model of migraine. Journal of Neuroscience. 43(9):1627-1642.
Walters ET, Crook, RJ, Neely GG, Price TJ, St John Smith E (2023) Persistent nociceptor
hyperactivity as a painful evolutionary adaptation. Trends in Neurosciences, 46(3):211-227
Schiff HV, Rivas CM, Pederson WP, Sandoval E, Gillman S, Prisco J, Kume M, Dussor G,
Vagner J, Ledford JG, Price TJ, DeFea KA, Boitano S. (2022) β-arrestin-biased proteinase-
16 activated receptor-2 antagonist C781 limits allergen-induced airway hyperresponsiveness and
inflammation. British Journal of Pharmacology. 180(5):667-680
Feb 2023
Hough A, Criswell C, Faruk A, Cavanaugh J, Kolber BJC, K TidgewellC (2023). Barbamide displays
affinity for membrane-bound receptors and impacts store-operated calcium entry in mouse sensory
neurons. Marine Drugs 21(2). doi: 10.3390/md21020110 *Equal contribution
Al-Karagholi MA, Kalatharan V, Ghanizada H, Gram C, Dussor G, Ashina M. (2023) Prolactin in
headache and migraine: a systemic review of clinical studies. Cephalalgia. 2023
Feb;43(2):3331024221136286. doi: 10.1177/03331024221136286
Kume M, Ahmad A, DeFea KA, Vagner J, Dussor G, Boitano S, Price TJ (2023) Protease-
Activated Receptor 2 (PAR2) expressed in sensory neurons contributes to signs of pain and
neuropathy in paclitaxel treated mice. Journal of Pain. S1526-5900(23)00441-8.
Sankaranarayanan I, Tavares-Ferreira D, Mwirigi JM, Mejia GL, Burton MD, Price TJ (2023)
Inducible co-stimulatory molecule (ICOS) alleviated paclitaxel-induced neuropathic pain via an
IL-10-mediated mechanism in female mice. Journal of Neuroinflammation. 20(1):32.
Ray PR, Shiers S, Caruso JP, Tavares-Ferreira D, Sankaranarayanan I, Uhelski ML, Li Y,
North RY, Tatsui C, Dussor G, Burton MD, Dougherty PM, Price TJ. (2023) RNA profiling of
human dorsal root ganglia reveals sex-difference in mechanisms promoting neuropathic pain.
Brain. 146(2) 749-766.
Jan 2023
Do TP, Hougaard A, Dussor G, Brennan KC, Amin FM. (2023) Migraine attacks are of peripheral origin:
the debate goes on. J Headache Pain. 2023 Jan 10;24(1):3. doi: 10.1186/s10194-022-01538-1
Upadhyayula, S+, Pemberton, E.J.+, Burton, M.D. Getting to the bottom of Cancer Treatment Pain.
Front. Young Minds. 11:783791. doi: 10.3389/frym.2022.783791
Dec 2022
Mason BN, Kallianpur R, Price TJ, Akopian AN, Dussor GO (2022) Prolactin signaling modulates
stress-induced behavioral responses in a preclinical mouse model of migraine. Headache. Dec 29. doi:
10.1111/head.14248.
Hegarty DM, Carrol JR, Nguyen D, Halls VS, Robbins DI, Price TJ, Dussor G, Aicher SA
(2022) Resveratrol increases tear production and ocular pain after corneal abrasion in male,
but not female, rats using a photorefractive keratectomy model. Experimental Eye Research.
225:109281.
Nov 2022
Kume M, Ahmad A, Shiers S, Burton MD, DeFea KA, Vagner J, Dussor G, Boitano S, Price TJ. (2022)
C781, a beta-arrestin biased antagonist at protease-activated receptor-2 (PAR2), displays in vivo efficacy
against protease-induced pain in mice. J Pain. 2022 Nov 20:S1526-5900(22)00454-0. doi:
10.1016/j.jpain.2022.11.006.
Castillo, Z.W.+ and Burton, M.D. Utilizing multiphoton imaging and integrative clearing to reveal sex
differences in neuroimmune interactions after nerve injury. Neural Regeneration Research. 2022
Papalampropoulou-Tsiridou M, Shiers S, Wang F, Godin AG, Price TJ, De Koninck Y (2022)
Distribution of acid-sensing ion channel subunits in human sensory neurons contrasts with that
in rodents. Brain Reports. 4(6):fcac256.
Oct 2022
Lackovic J, Price TJ, Dussor G (2022) MNK1/2 contributes to periorbital hypersensitivity and
hyperalgesic priming in preclinical migraine models. Brain. Oct 27. awac386. doi:
10.1093/brain/awac386
Sept 2022
Allen HNG, Chaudhry S, Hong VMG, Lewter LAPD, Sinha GP, Carrasquillo Y, Taylor BK, Kolber BJC.
(2023) A parabrachial-to-amygdala circuit that determines hemispheric lateralization of
somatosensory processing. Biological Psychiatry 93(4): 370-381. doi: 10.1016/j.biopsych.2022.09.010. Note: Accepted for publication Fall 2022
Mikesell AR, Isaeva O, Moehring F, Sadler KE, Menzel AD, Stucky CL (2022). Keratinocyte PIEZO1
modulates cutaneous mechanosensation. eLife11:e65987
Tierney, J.A.+, Uong, C.D.+, Lenert, M.E., Williams, M.+, Burton, M.D. High-fat Diet causes
mechanical allodynia in the absence of previous injury or diabetic pathology. Scientific Reports. 2022
Sep 1:12(1). Doi 10.1038/s41598-022-18281-x
Aug 2022
Garner, K.M. and Burton, M.D. The sex-specific role of sensory neurons LKB1 on metabolic stress-
induced mechanical hypersensitivity and mitochondrial respiration. American Journal of Physiology:
Regulatory, Integrative, & Comparative Physiology. 2022 Aug 1:323(2) doi:10.1152/ajpregu00279.2020
July 2022
Ray PR, Shiers S, Caruso JP, Tavares-Ferreira D, Sankaranarayanan I, Uhelski ML, Li Y, North RY,
Tatsui C, Dussor G, Burton MD, Dougherty PM, Price TJ. (2022) RNA profiling of human dorsal root
ganglia reveals sex-differences in mechanisms promoting neuropathic pain. Brain. 2022 Jul 22:awac266.
doi: 10.1093/brain/awac266.
June 2022
Schiff HV, Rivas CM, Pederson WP, Sandoval E, Gillman S, Prisco J, Kume M, Dussor G, Vagner J,
Ledford JG, Price TJ, DeFea KA, Boitano S. (2022) Beta-arrestin-biased proteinase-activated receptor-2
antagonist C781 limits allergen-induced airway hyperresponsiveness and inflammation. Br J Pharmacol.
2022 Jun 23. doi: 10.1111/bph.15903.
Lenert, M.E., Szabo-Pardi, T.A., Burton, M.D. Regulatory T-cells and IL-5 mediate pain outcomes in a
preclinical model of chronic muscle pain. Molecular Pain. 2022 Jun 17. Doi: 10.1177/17448069221
Letzen, J.E., Mathur, V.A., Janevic, M.R., Burton, M.D., Hood, A.M., Morais, C.A., Booker, S.Q.,
Campbell, C.M., Aroke, E.N., Campbell, L.C., Merriwether, E.N. Confronting Racism in All Forms of
Pain Research: Reframing Study Designs. Journal of Pain. 2022 Jun. doi: 10.1016/j.jpain.2022.01.010
April 2022
Vidal A, Jha S, Hassler S, Price TJ, Busso C (2022) Face detection and grimace scale
prediction of white furred mice. Machine Learning with Applications. 8: 100312
March 2022
Trask S, Mogil JS, Helmstetter FJ, Stucky CL, Sadler KE† (2022). Contextual control of conditioned pain
tolerance and endogenous analgesic systems eLife 11:e75283
Mecklenburg J, Wangzhou A, Hovhannisyan AH, Barba-Escobedo P, Shein SA, Zou Y, Weldon K, Lai
Z, Goffin V, Dussor G, Tumanov AV, Price TJ, Akopian AN. (2022) Sex-dependent pain trajectories
induced by prolactin require an inflammatory response for pain resolution. Brain Behav Immun. 2022
Mar;101:246-263. doi: 10.1016/j.bbi.2022.01.016. Epub 2022 Jan 19
Lenert, M.E., Agalave, N.M., Gomez, R.+, Lane, B.T.+, Daily, DL, Geasland, K.G., Crofford, L.J.,
Sluka, K.A., Merriwether, E.N., Burton, M.D. Translating outcomes from the clinical setting to
preclinical models: chronic pain and functionality in chronic musculoskeletal pain. Pain Medicine. 2022
Mar 24:pnac047.doli: 10.1093/pm/pnac047
Hall, B.E., Macdonald, E., Cassidy, M., Yun, S., Sapio, M., Ray, P., Doty, M., Nara, P. Burton. M.D.,
Shiers, S., Ray-Chaudhury, A., Mannes, A.J., Price, T.J., Iadarola, M.J. Kulkarni, A.B. Transcriptomic
analysis of human sensory neurons in painful diabetic neuropathy reveals inflammation and neuronal
loss. Scientific Reports. 2022 Mar. doi: 10.1038/s41598-022-08100-8
Paige C, Plasencia-Fernandez I, Kume M, Papalampropoulou-Tsiridou M, Lorenzo LE, David
ET, He L, Mejia GL, Driskill C, Ferrini F, Feldhaus AL, Garcia-Martinez LF, Akopian AN, De
Koninck Y, Dussor G, Price TJ (2022) A female-specific role for Calcitonin Gene-Related
Peptide (CGRP) in rodent pain models. Journal of Neuroscience. 42(10): 1930-1944
Feb 2022
Tavares-Ferreira D, Shiers S, Ray PR, Wangzhou A, Jeevakumar V, Sankaranarayanan I, Cervantes AM,
Reese JC, Chamessian A, Copits BA, Dougherty PM, Gereau RW 4th, Burton MD, Dussor G, Price TJ.
(2022) Spatial transcriptomics of dorsal root ganglia identifies molecular signatures of human
nociceptors. Sci Transl Med. 2022 Feb 16;14(632):eabj8186. doi: 10.1126/scitranslmed.abj8186
Allahyari RV, Heinsinger NM, Hwang D, Jaffe DA, Rasouli J, Shiers S, Thomas SJ, Price TJ,
Rostami A, Lepore AC (2022) Response of astrocyte subpopulations following spinal cord
injury. Cells. 11(4) 721
McFarland AJ, Ray PR, Bhai S, Levine B, Price TJ (2022) RNA sequencing on muscle biopsy
from a 5-week bedrest study reveals the effect of exercise and potential interactions with
dorsal root ganglion neurons. Physiological Reports. 10(3) e15176
Jan 2022
Treat APD, Henri VUG, Liu J*, Shen J, Gil-Silva M, Morales MUG, Rade AUG, Tidgewell K, Kolber BC,
Y ShenC (2022). Novel TRPV1 modulators with reduced pungency induce analgesic effects in mice.
ACS Omega (2022). doi: 10.1021/acsomega.1c05727. *Equal contribution
Gokcinar AH, Adams M, Price TJ, Cakanyildirim M (2022) Balanced opioid prescribing via a
clinical tradeoff: pain relief versus adverse effects of discomfort, dependent and
tolerance/hypersensitivity. Decision Analysis. 19(4) 297-318.
Li J, Price TJ, Baccei M (2022) D1/D5 dopamine receptors and mGluR5 jointly enable non-
Hebbian long-term potentiation at sensory synapses onto lamina I spinoparabrachial neurons.
Journal of Neuroscience. 42(3): 350-361
Mason BN, Kallianpur R, Price TJ, Akopian AN, Dussor G (2022) Prolactin signaling
modulates stress-induced behavioral responses in a preclinical mouse model of migraine.
Headache. 62(1) 11-25.
July 2021
Journal of Comparative Neurology
Peripheral sensory neurons are characterized by their size, molecular profiles, and physiological responses to specific stimuli. In mouse, the peptidergic and non-peptidergic subsets of nociceptors are distinct and innervate different lamina of the spinal dorsal horn. The unique molecular signature and neuroanatomical organization of these neurons supports a labeled line theory for certain types of nociceptive stimuli. However, long-standing evidence supports the polymodal nature of nociceptors in many species. We have recently shown that the peptidergic marker, CGRP, and the non-peptidergic marker, P2X3R, show largely overlapping expression at the mRNA level in human dorsal root ganglion (DRG). Herein, our aim was to assess the protein distribution of nociceptor markers, including their central projections, in the human DRG and spinal cord. Using DRGs obtained from organ donors, we observed that CGRP and P2X3R were co-expressed by approximately 33% of human DRG neurons and TrpV1 was expressed in ~60% of human DRG neurons. In the dorsal spinal cord, CGRP, P2X3R, TrpV1, and Nav1.7 proteins stained the entirety of lamina 1-2, with only P2XR3 showing a gradient of expression. This was confirmed by measuring the size of the substantia gelatinosa using Hematoxylin and Eosin staining of adjacent sections. Our findings are consistent with the known polymodal nature of most primate nociceptors and indicate that the central projection patterns of nociceptors are different between mice and humans. Elucidating how human nociceptors connect to subsets of dorsal horn neurons will be important for understanding the physiological consequences of these species differences.
Shiers S, Sankaranarayanan I, Jeevakumar V, Cervantes A, Reese JC, Price TJ
June 2021
Theranostics
Nasal administration of mitochondria reverses chemotherapy-induced cognitive deficits.
The protease activated receptor (PAR) family is a group of G-protein coupled receptors (GPCRs) activated by proteolytic cleavage of the extracellular domain. PARs are expressed in a variety of cell types with crucial roles in homeostasis, immune responses, inflammation, and pain. PAR3 is the least researched of the four PARs, with little known about its expression and function. We sought to better understand its potential function in the peripheral sensory nervous system. Mouse single-cell RNA sequencing data demonstrates that PAR3 is widely expressed in dorsal root ganglion (DRG) neurons. Co-expression of PAR3 mRNA with other PARs was identified in various DRG neuron subpopulations, consistent with its proposed role as a coreceptor of other PARs. We developed a lipid tethered PAR3 agonist, C660, that selectively activates PAR3 by eliciting a Ca2+response in DRG and trigeminal neurons. In vivo, C660 induces mechanical hypersensitivity and facial grimacing in WT but not PAR3-/- mice. We characterized other nociceptive phenotypes in PAR3-/- mice and found a loss of hyperalgesic priming in response to IL-6, carrageenan, and a PAR2 agonist, suggesting that PAR3 contributes to long-lasting nociceptor plasticity in some contexts. To examine the potential role of PAR3 in regulating the activity of other PARs in sensory neurons, we administered PAR1, PAR2, and PAR4 agonists and assessed mechanical and affective pain behaviors in WT and PAR3-/- mice. We observed that the nociceptive effects of PAR1 agonists were potentiated in the absence of PAR3. Our findings suggest a complex role of PAR3 in the physiology and plasticity of nociceptors. PERSPECTIVE: We evaluated the role of PAR3, a G-protein coupled receptor, in nociception by developing a selective peptide agonist. Our findings suggest that PAR3 contributes to nociception in various contexts and plays a role in modulating the activity of other PARs.
Alexander JF, Seua AV, Arroyo LD, Ray PR, Wangzhou A, Heib-Luckemann L, Schedlowski M, Price TJ, Kavelaars A, Heijnen CJ
June 2021
Pain
A peptide encoded within a 5′ untranslated region promotes pain sensitization in mice
Translational regulation permeates neuronal function. Nociceptors are sensory neurons responsible for the detection of harmful stimuli. Changes in their activity, termed plasticity, are intimately linked to the persistence of pain. Although inhibitors of protein synthesis robustly attenuate pain-associated behavior, the underlying targets that support plasticity are largely unknown. Here, we examine the contribution of protein synthesis in regions of RNA annotated as noncoding. Based on analyses of previously reported ribosome profiling data, we provide evidence for widespread translation in noncoding transcripts and regulatory regions of mRNAs. We identify an increase in ribosome occupancy in the 5′ untranslated regions of the calcitonin gene-related peptide (CGRP/Calca). We validate the existence of an upstream open reading frame (uORF) using a series of reporter assays. Fusion of the uORF to a luciferase reporter revealed active translation in dorsal root ganglion neurons after nucleofection. Injection of the peptide corresponding to the calcitonin gene-related peptide-encoded uORF resulted in pain-associated behavioral responses in vivo and nociceptor sensitization in vitro. An inhibitor of heterotrimeric G protein signaling blocks both effects. Collectively, the data suggest pervasive translation in regions of the transcriptome annotated as noncoding in dorsal root ganglion neurons and identify a specific uORF-encoded peptide that promotes pain sensitization through GPCR signaling.
Barragan-Iglesias P, Kunder N, Wanghzou A, Black B, Ray PR, Lou TC, de la Peña JB, Atmaramani R, Shukla T, Pancrazio JJ, Price TJ, Campbell ZT
June 2021
Neural Regeneration Research
The role of microglia versus peripheral macrophages in maladaptive plasticity after nerve injury
Microglia and macrophages in the development of maladaptive plastic changes after peripheral nerve injury: Microglia and macrophages encompass the innate immune response to injury in the central and peripheral nervous systems, respectively, and are intimately involved in the pathogenesis of maladaptive changes (Tsuda, 2019). These dynamic cells can influence neuronal activity in active and quiescent states. Conflicting findings argue that peripheral macrophages facilitate the development of nerve injury-induced neuropathic pain, as opposed to central microglia (Lopes et al., 2017; Yu et al., 2020). It is imperative to discern their spatiotemporal contributions to the development and maintenance of maladaptive conditions, such as neuropathic pain (Inoue and Tsuda, 2018). The individual role of these cell types is difficult to parse out because both microglia and macrophages exhibit a keen ability to react quickly to injury and remain reactive after injury-induced changes. Appropriate methods to isolate and characterize these cells in downstream applications is necessary to uncover key findings (Agalave et al., 2020)
Szabo-Pardi, T.A., Agalave, N.M., Burton, M.D.
June 2021
Journal of Pain
Mwirigi J, Kume M, Hassler SN, Ahmad A, Ray PR, Jiang C, Chamessian A, Mseeh N, Ludwig BP, Rivera BD, Nieman MT, Van de Ven T, Ji RR, Dussor G, Boitano S, Vagner J, Price TJ
May 2021
Neuron
Chronic pain is a disabling disease with limited treatment options. While animal models have revealed important aspects of pain neurobiology, therapeutic translation of this knowledge requires our understanding of these cells and networks of pain in humans. We propose a multi-institutional collaboration to rigorously and ethically address this challenge.
Renthal W, Chamessian A, Curatolo M, Davidson S, Burton M, Dib-Hajj S, Dougherty PM, Ebert A, Gereau RW, Ghetti A, Gold MS, Menichella DM, Mercier P, Ray W, Salvemini D, Seal RP, Waxman S, Woolf C, Stucky C, Price TJ
May 2021
Brain
Studying human nociceptors: from fundamentals to clinic
Chronic pain affects one in five of the general population and is the third most important cause of disability-adjusted life-years globally. Unfortunately, treatment remains inadequate due to poor efficacy and tolerability. There has been a failure in translating promising preclinical drug targets into clinic use. This reflects challenges across the whole drug development pathway, from preclinical models to trial design. Nociceptors remain an attractive therapeutic target: their sensitization makes an important contribution to many chronic pain states, they are located outside the blood–brain barrier, and they are relatively specific. The past decade has seen significant advances in the techniques available to study human nociceptors, including: the use of corneal confocal microscopy and biopsy samples to observe nociceptor morphology, the culture of human nociceptors (either from surgical or post-mortem tissue or using human induced pluripotent stem cell derived nociceptors), the application of high throughput technologies such as transcriptomics, the in vitro and in vivo electrophysiological characterization through microneurography, and the correlation with pain percepts provided by quantitative sensory testing. Genome editing in human induced pluripotent stem cell-derived nociceptors enables the interrogation of the causal role of genes in the regulation of nociceptor function. Both human and rodent nociceptors are more heterogeneous at a molecular level than previously appreciated, and while we find that there are broad similarities between human and rodent nociceptors there are also important differences involving ion channel function, expression, and cellular excitability. These technological advances have emphasized the maladaptive plastic changes occurring in human nociceptors following injury that contribute to chronic pain. Studying human nociceptors has revealed new therapeutic targets for the suppression of chronic pain and enhanced repair. Cellular models of human nociceptors have enabled the screening of small molecule and gene therapy approaches on nociceptor function, and in some cases have enabled correlation with clinical outcomes. Undoubtedly, challenges remain. Many of these techniques are difficult to implement at scale, current induced pluripotent stem cell differentiation protocols do not generate the full diversity of nociceptor populations, and we still have a relatively poor understanding of inter-individual variation in nociceptors due to factors such as age, sex, or ethnicity. We hope our ability to directly investigate human nociceptors will not only aid our understanding of the fundamental neurobiology underlying acute and chronic pain but also help bridge the translational gap.
Middleton SJ, Barry AM, Comini M, Li Y, Ray PR, Shiers S, Themistocleous AC, Uhelski ML, Yang X, Dougherty PM, Price TJ, Bennett DL
May 2021
Matter
Nanotransducers for Wireless Neuromodulation
Understanding the signal transmission and processing within the central nervous system (CNS) is a grand challenge in neuroscience. The past decade has witnessed significant advances in the development of new tools to address this challenge. Development of these new tools draws diverse expertise from genetics, materials science, electrical engineering, photonics and other disciplines. Among these tools, nanomaterials have emerged as a unique class of neural interfaces due to their small size, remote coupling and conversion of different energy modalities, various delivery methods, and mitigated chronic immune responses. In this review, we will discuss recent advances in nanotransducers to modulate and interface with the neural system without physical wires. Nanotransducers work collectively to modulate brain activity through optogenetic, mechanical, thermal, electrical and chemical modalities. We will compare important parameters among these techniques including the invasiveness, spatiotemporal precision, cell-type specificity, brain penetration, and translation to large animals and humans. Important areas for future research include a better understanding of the nanomaterials-brain interface, integration of sensing capability for bidirectional closed-loop neuromodulation, and genetically engineered functional materials for cell-type specific neuromodulation.
Li, X., Xiong, H., Rommelfanger, N., Xu, X., Youn, J., Slesinger, P., Hong, G. and Qin. Z.
May 2021
Science Translational Medicine
Tactile and spontaneous pains are poorly managed symptoms of inflammatory and neuropathic injury. Here, we found that transient receptor potential canonical 5 (TRPC5) is a chief contributor to both of these sensations in multiple rodent pain models. Use of TRPC5 knockout mice and inhibitors revealed that TRPC5 selectively contributes to the mechanical hypersensitivity associated with CFA injection, skin incision, chemotherapy induced peripheral neuropathy, sickle cell disease, and migraine, all of which were characterized by elevated concentrations of lysophosphatidylcholine (LPC). Accordingly, exogenous application of LPC induced TRPC5-dependent behavioral mechanical allodynia, neuronal mechanical hypersensitivity, and spontaneous pain in naïve mice. Lastly, we found that 75% of human sensory neurons express TRPC5, the activity of which is directly modulated by LPC. On the basis of these results, TRPC5 inhibitors might effectively treat spontaneous and tactile pain in conditions characterized by elevated LPC.
Sadler KE, Moehring F, Shiers SI, Laskowski LJ, Mikesell AR, Plautz ZR, Brezinski AN, Mecca CM, Dussor G, Price TJ, McCorvy JD, Stucky CL
May 2021
Neuroscience
Because somatosensory PNS neurons, in particular nociceptors, are specially tuned to be able to detect a wide variety of both exogenous and endogenous signals, one might assume that these neurons express a greater variety of receptor genes. This assumption has not been formally tested. Because cells detect such signals via cell surface receptors, we sought to formally test the hypothesis that PNS neurons might express a broader array of cell surface receptors than CNS neurons using existing single cell RNA sequencing resources from mouse. We focused our analysis on ion channels, G-protein coupled receptors (GPCRS), receptor tyrosine kinase and cytokine family receptors. In partial support of our hypothesis, we found that mouse PNS somatosensory, sympathetic and enteric neurons and CNS neurons have similar receptor expression diversity in families of receptors examined, with the exception of GPCRs and cytokine receptors which showed greater diversity in the PNS. Surprisingly, these differences were mostly driven by enteric and sympathetic neurons, not by somatosensory neurons or nociceptors. Secondary analysis revealed many receptors that are very specifically expressed in subsets of PNS neurons, including some that are unique among neurons for nociceptors. Finally, we sought to examine specific ligand-receptor interactions between T cells and PNS and CNS neurons. Again, we noted that most interactions between these cells are shared by CNS and PNS neurons despite the fact that T cells only enter the CNS under rare circumstances. Our findings demonstrate that both PNS and CNS neurons express an astonishing array of cell surface receptors and suggest that most neurons are tuned to receive signals from other cells types, in particular immune cells.
Wangzhou A, Paige C, Ray PR, Dussor G, Price TJ
April 2021
J Neurosci
Despite their opposing actions on food intake, POMC and NPY/AgRP neurons in the arcuate nucleus of the hypothalamus (ARH) are derived from the same progenitors that give rise to ARH neurons. However, the mechanism whereby common neuronal precursors subsequently adopt either the anorexigenic (POMC) or the orexigenic (NPY/AgRP) identity remains elusive. We hypothesize that POMC and NPY/AgRP cell fates are specified and maintained by distinct intrinsic factors. In search of them, we profiled the transcriptomes of developing POMC and NPY/AgRP neurons in mice. Moreover, cell-type-specific transcriptomic analyses revealed transcription regulators that are selectively enriched in either population, but whose developmental functions are unknown in these neurons. Among them, we found the expression of the PR domain-containing factor 12 (Prdm12) was enriched in POMC neurons but absent in NPY/AgRP neurons. To study the role of Prdm12 in vivo, we developed and characterized a floxed Prdm12 allele. Selective ablation of Prdm12 in embryonic POMC neurons led to significantly reduced Pomc expression as well as early-onset obesity in mice of either sex that recapitulates symptoms of human POMC deficiency. Interestingly, however, specific deletion of Prdm12 in adult POMC neurons showed that it is no longer required for Pomc expression or energy balance. Collectively, these findings establish a critical role for Prdm12 in the anorexigenic neuron identity and suggest that it acts developmentally to program body weight homeostasis. Finally, the combination of cell-type-specific genomic and genetic analyses provides a means to dissect cellular and functional diversity in the hypothalamus whose neurodevelopment remains poorly studied
Chen X., Wyler S.C., Li L., Arnold A.G., Wan R., Jia L., Landy M.A., Lai H.C., Xu P., Liu C.
April 2021
PLOS Genetics
Sex-stratified genome-wide association study of multisite chronic pain in UK Biobank
Chronic pain is highly prevalent worldwide and imparts a significant socioeconomic and public health burden. Factors influencing susceptibility to, and mechanisms of, chronic pain development, are not fully understood, but sex is thought to play a significant role, and chronic pain is more prevalent in women than in men. To investigate sex differences in chronic pain, we carried out a sex-stratified genome-wide association study of Multisite Chronic Pain (MCP), a derived chronic pain phenotype, in UK Biobank on 178,556 men and 209,093 women, as well as investigating sex-specific genetic correlations with a range of psychiatric, autoimmune and anthropometric phenotypes and the relationship between sex-specific polygenic risk scores for MCP and chronic widespread pain. We also assessed whether MCP-associated genes showed expression pattern enrichment across tissues. A total of 123 SNPs at five independent loci were significantly associated with MCP in men. In women, a total of 286 genome-wide significant SNPs at ten independent loci were discovered. Meta-analysis of sex-stratified GWAS outputs revealed a further 87 independent associated SNPs. Gene-level analyses revealed sex-specific MCP associations, with 31 genes significantly associated in females, 37 genes associated in males, and a single gene, DCC, associated in both sexes. We found evidence for sex-specific pleiotropy and risk for MCP was found to be associated with chronic widespread pain in a sex-differential manner. Male and female MCP were highly genetically correlated, but at an rg of significantly less than 1 (0.92). All 37 male MCP-associated genes and all but one of 31 female MCP-associated genes were found to be expressed in the dorsal root ganglion, and there was a degree of enrichment for expression in sex-specific tissues. Overall, the findings indicate that sex differences in chronic pain exist at the SNP, gene and transcript abundance level, and highlight possible sex-specific pleiotropy for MCP. Results support the proposition of a strong central nervous-system component to chronic pain in both sexes, additionally highlighting a potential role for the DRG and nociception.
Johnston KJA, Ward J, Ray PR, Adams MJ, McIntosh AM, Smith BH, Strawbridge RJ, Price TJ, Smith DJ, Nicholl BI, Bailey MES
March 2021
Brain, Behavior, and Immunity
Recent studies have brought to light the necessity to discern sex-specific differences in various pain states and different cell-types that mediate these differences. These studies have uncovered the role of neuroimmune interactions to mediate pain states in a sex-specific fashion. While investigating immune function in pain development, we discovered that females utilize immune components of sensory neurons to mediate neuropathic pain development. We utilized two novel transgenic mouse models that either restore expression of toll-like receptor (TLR) 4 in Nav1.8 nociceptors on a TLR4-null background (TLR4LoxTB) or remove TLR4 specifically from Nav1.8 nociceptors (TLR4fl/fl). After spared nerve injury (SNI), a model of neuropathic injury, we observed a robust female-specific onset of mechanical hypersensitivity in our transgenic animals. Female Nav1.8-TLR4fl/fl knockout animals were less mechanically sensitive than cre-negative TLR4fl/fl littermates. Conversely, female Nav1.8-TLR4LoxTB reactivated animals were as mechanically sensitive as their wild-type counterparts. These sex and cell-specific effects were not recapitulated in male animals of either strain. Additionally, we find the danger associated molecular pattern, high mobility group box-1 (HGMB1), a potent TLR4 agonist, localization and ATF3 expression in females is dependent on TLR4 expression in dorsal root ganglia (DRG) populations following SNI. These experiments provide novel evidence toward sensory neuron specific modulation of pain in a sex-dependent manner.
Szabo-Pardi, T.A., Barron, L.R., Burton, M.D.
March 2021
Frontiers in Immunology
Neuroimmune consequences of eIF4E phosphorylation on chemotherapy-induced peripheral neuropathy
Chemotherapy-induced peripheral neuropathy (CIPN) is a major dose-limiting side effect that occurs in up to 63% of patients and has no known effective treatment. A majority of studies do not effectively assess sex differences in the onset and persistence of CIPN. Here we investigated the onset of CIPN, a point of therapeutic intervention where we may limit, or even prevent the development of CIPN. We hypothesized that cap-dependent translation mechanisms are important in early CIPN development and the bi-directional crosstalk between immune cells and nociceptors plays a complementary role to CIPN establishment and sex differences observed. In this study, we used wild type and eIF4E-mutant mice of both sexes to investigate the role of cap-dependent translation and the contribution of immune cells and nociceptors in the periphery and glia in the spinal cord during paclitaxel-induced peripheral neuropathy. We found that systemically administered paclitaxel induces pain-like behaviors in both sexes, increases helper T-lymphocytes, downregulates cytotoxic T-lymphocytes, and increases mitochondrial dysfunction in dorsal root ganglia neurons; all of which is eIF4E-dependent in both sexes. We identified a robust paclitaxel-induced, eIF4E-dependent increase in spinal astrocyte immunoreactivity in males, but not females. Taken together, our data reveals that cap-dependent translation may be a key pathway that presents relevant therapeutic targets during the early phase of CIPN. By targeting the eIF4E complex, we may reduce or reverse the negative effects associated with chemotherapeutic treatments.
Agalave, N.M., Mody, P.H., Szabo-Pardi, T.A., Jeong, H.S., Burton, M.D.
March 2021
Journal of Biomechanical Engineering
Computational Investigation of Protein Photoinactivation by Molecular Hyperthermia
To precisely control protein activity in a living system is a challenging yet long-pursued objective in biomedical sciences. Recently, we have developed a new approach named molecular hyperthermia (MH) to photoinactivate protein activity of interest without genetic modification. MH utilizes nanosecond laser pulse to create nanoscale heating around plasmonic nanoparticles to inactivate adjacent protein in live cells. Here we use a numerical model to study important parameters and conditions for MH to efficiently inactivate proteins in nanoscale. To quantify the protein inactivation process, the impact zone is defined as the range where proteins are inactivated by the nanoparticle localized heating. Factors that reduce the MH impact zone include the laser pulse duration, temperature-dependent thermal conductivity (versus constant properties), and nonspherical nanoparticle geometry. In contrast, the impact zone is insensitive to temperature-dependent material density and specific heat, as well as thermal interface resistance based on reported data in the literature. The low thermal conductivity of cytoplasm increases the impact zone. Different proteins with various Arrhenius kinetic parameters have significantly different impact zones. This study provides guidelines to design the protein inactivation process by MH
Kang, P., Chen, X., Fall, O., Cazals, J., Randrianalisoa, J. and Qin, Z.
March 2021
Sci Signal
A ligand-receptor interactome platform for discovery of pain mechanisms and therapeutic targets
In the peripheral nervous system, ligand-receptor interactions between cells and neurons shape sensory experience, including pain. We set out to identify the potential interactions between sensory neurons and peripheral cell types implicated in disease-associated pain. Using mouse and human RNA sequencing datasets and computational analysis, we created interactome maps between dorsal root ganglion (DRG) sensory neurons and an array of normal cell types, as well as colitis-associated glial cells, rheumatoid arthritis-associated synovial macrophages, and pancreatic tumor tissue. These maps revealed a common correlation between the abundance of heparin-binding EGF-like growth factor (HBEGF) in peripheral cells with that of its receptor EGFR (a member of the ErbB family of receptors) in DRG neurons. Subsequently, we confirmed that increased abundance of HBEGF enhanced nociception in mice, likely acting on DRG neurons through ErbB family receptors. Collectively, these interactomes highlight ligand-receptor interactions that may lead to treatments for disease-associated pain and, furthermore, reflect the complexity of cell-to-neuron signaling in chronic pain states.
Wangzhou A, Paige C, Neerukonda SV, Naik DK, Kume M, David ET, Dussor G, Ray PR, Price TJ.
March 2021
Biomedical Engineering Online
Visceral pressure stimulator for exploring hollow organ pain: a pilot study
Background: The regulation and control of pressure stimuli is useful for many studies of pain and nociception especially those in the visceral pain field. In many in vivo experiments, distinct air and liquid stimuli at varying pressures are delivered to hollow organs such as the bladder, vagina, and colon. These stimuli are coupled with behavioral, molecular, or physiological read-outs of the response to the stimulus. Care must be taken to deliver precise timed stimuli during experimentation. For example, stimuli signals can be used online to precisely time-lock the stimulus with a physiological output. Such precision requires the development of specialized hardware to control the stimulus (e.g., air) while providing a precise read-out of pressure and stimulus signal markers.
Methods: In this study, we designed a timed pressure regulator [termed visceral pressure stimulator (VPS)] to control air flow, measure pressure (in mmHg), and send stimuli markers to online software. The device was built using a simple circuit and primarily off-the-shelf parts. A separate custom inline analog-to-digital pressure converter was used to validate the real pressure output of the VPS.
Results: Using commercial physiological software (Spike2, CED), we were able to measure mouse bladder pressure continuously during delivery of unique air stimulus trials in a mouse while simultaneously recording an electromyogram (EMG) of the overlying abdominal muscles.
Conclusions: This device will be useful for those who need to (1) deliver distinct pressure stimuli while (2) measuring the pressure in real-time and (3) monitoring stimulus on-off using physiological software.
DeLong M, Gil-Silva M, Hong VG, Babyok OUG, BJ KolberC
March 2021
PNAS
The CysLT2R receptor mediates leukotriene C4-driven acute and chronic itch.
Acute and chronic itch are burdensome manifestations of skin pathologies including allergic skin diseases and atopic dermatitis, but the underlying molecular mechanisms are not well understood. Cysteinyl leukotrienes (CysLTs), comprising LTC4, LTD4, and LTE4, are produced by immune cells during type 2 inflammation. Here, we uncover a role for LTC4 and its signaling through the CysLT receptor 2 (CysLT2R) in itch. Cysltr2 transcript is highly expressed in dorsal root ganglia (DRG) neurons linked to itch in mice. We also detected CYSLTR2 in a broad population of human DRG neurons. Injection of leukotriene C4 (LTC4) or its nonhydrolyzable form NMLTC4, but neither LTD4nor LTE4, induced dose-dependent itch but not pain behaviors in mice. LTC4-mediated itch differed in bout duration and kinetics from pruritogens histamine, compound 48/80, and chloroquine. NMLTC4-induced itch was abrogated in mice deficient for Cysltr2 or when deficiency was restricted to radioresistant cells. Itch was unaffected in mice deficient for Cysltr1, Trpv1, or mast cells (WShmice). CysLT2R played a role in itch in the MC903 mouse model of chronic itch and dermatitis, but not in models of dry skin or compound 48/80- or Alternaria-induced itch. In MC903-treated mice, CysLT levels increased in skin over time, and Cysltr2 -/- mice showed decreased itch in the chronic phase of inflammation. Collectively, our study reveals that LTC4 acts through CysLT2R as its physiological receptor to induce itch, and CysLT2R contributes to itch in a model of dermatitis. Therefore, targeting CysLT signaling may be a promising approach to treat inflammatory itch.
Voisin T, Perner C, Messou M, Shiers S, Ualiyeva S, Kanaoka Y, Price TJ, Sokol CL, Bankova LG, Austen KF, Chiu IM
March 2021
Cell Reports
Loss of Prdm12 during development, but not in mature nociceptors, causes defects in pain sensation
Prdm12 is a key transcription factor in nociceptor neurogenesis. Mutations of Prdm12 cause congenital insensitivity to pain (CIP) from failure of nociceptor development. However, precisely how deletion of Prdm12 during development or adulthood affects nociception is unknown. Here, we employ tissue- and temporal-specific knockout mouse models to test the function of Prdm12 during development and in adulthood. We find that constitutive loss of Prdm12 causes deficiencies in proliferation during sensory neurogenesis. We also demonstrate that conditional knockout from dorsal root ganglia (DRGs) during embryogenesis causes defects in nociception. In contrast, we find that, in adult DRGs, Prdm12 is dispensable for most pain-sensation and injury-induced hypersensitivity. Using transcriptomic analysis, we find mostly unique changes in adult Prdm12 knockout DRGs compared with embryonic knockout and that PRDM12 is likely a transcriptional activator in the adult. Overall, we find that the function of PRDM12 changes over developmental time.
Landy M.A., Goyal M., Casey K.M., Liu C., Lai H.C.
March 2021
Annals of Neurology
Meningeal CGRP-prolactin interaction evokes female-specific migraine behavior
Objective
Migraine is three times more common in women. CGRP plays a critical role in migraine pathology and causes female-specific behavioral responses upon meningeal application. These effects are likely mediated through interactions of CGRP with signaling systems specific to females. Prolactin (PRL) levels have been correlated with migraine attacks. Here, we explore a potential interaction between CGRP and PRL in the meninges.
Methods
Prolactin, CGRP, and receptor antagonists CGRP8-37 or Δ1-9-G129R-hPRL were administered onto the dura of rodents followed by behavioral testing. Immunohistochemistry was used to examine PRL, CGRP and Prolactin receptor (Prlr) expression within the dura. Electrophysiology on cultured and back-labeled trigeminal ganglia (TG) neurons was used to assess PRL-induced excitability. Finally, the effects of PRL on evoked CGRP release from ex vivo dura were measured.
Results
We found that dural PRL produced sustained and long-lasting migraine-like behavior in cycling and ovariectomized female, but not male rodents. Prlr was expressed on dural afferent nerves in females with little-to-no presence in males. Consistent with this, PRL increased excitability only in female TG neurons innervating the dura and selectively sensitized CGRP release from female ex vivo dura. We demonstrate crosstalk between PRL and CGRP systems as CGRP8-37 decreases migraine-like responses to dural PRL. Reciprocally, Δ1-9-G129R-hPRL attenuates dural CGRP-induced migraine behaviors. Similarly, Prlr deletion from sensory neurons significantly reduced migraine-like responses to dural CGRP.
Interpretation
This CGRP-PRL interaction in the meninges is a mechanism by which these peptides could produce female-selective responses and increase the prevalence of migraine in women
Avona A, Mason BN, Burgos-Vega C, Hovhannisyan AH, Belugin SN, Mecklenberg J, Goffin V, Wajahat N, Price TJ, Akopian AN, Dussor G
March 2021
Science Signaling
A ligand-receptor interactome platform for discovery of pain mechanisms and therapeutic targets
In the peripheral nervous system, ligand-receptor interactions between cells and neurons shape sensory experience, including pain. We set out to identify the potential interactions between sensory neurons and peripheral cell types implicated in disease-associated pain. Using mouse and human RNA sequencing datasets and computational analysis, we created interactome maps between dorsal root ganglion (DRG) sensory neurons and an array of normal cell types, as well as colitis-associated glial cells, rheumatoid arthritis-associated synovial macrophages, and pancreatic tumor tissue. These maps revealed a common correlation between the abundance of heparin-binding EGF-like growth factor (HBEGF) in peripheral cells with that of its receptor EGFR (a member of the ErbB family of receptors) in DRG neurons. Subsequently, we confirmed that increased abundance of HBEGF enhanced nociception in mice, likely acting on DRG neurons through ErbB family receptors. Collectively, these interactomes highlight ligand-receptor interactions that may lead to treatments for disease-associated pain and, furthermore, reflect the complexity of cell-to-neuron signaling in chronic pain states.
Wangzhou A, Paige C, Neerukonda SV, Naik DK, Kume M, David ET, Dussor G, Ray PR, Price TJ
February 2021
Pain Medicine
Objective: This pilot trial examined the effects of a combined intervention of mindfulness meditation followed by aerobic walking exercise compared with a control condition in chronic low back pain patients. We hypothesized that meditation before exercise would reduce disability, pain, and anxiety by increasing mindfulness prior to physical activity compared with an audiobook control group.
Participants: Thirty-eight adults completed either meditation and exercise treatment (MedExT) (n=18) or an audiobook control condition (n=20).
Setting: Duquesne University Exercise Physiology Laboratory.
Design: A pilot, assessor-blinded, randomized controlled trial.
Methods: Over a 4-week period, participants in the MedExT group performed 12-17 minutes of guided meditation followed by 30 minutes of moderate-intensity walking exercise 5 days per week. Measures of disability, pain, mindfulness, and anxiety were taken at baseline and postintervention. Pain perception measurements were taken daily.
Results: Compared with the control group, we observed larger improvements in disability in the MedExT intervention, although the changes were modest and not statistically significant (mean between-group difference, -1.24; 95% confidence interval [CI], -3.1 to 0.6). For secondary outcome measures, MedExT increased mindfulness (within-group) from pre-intervention to postintervention (P=0.0141). Additionally, mean ratings of low back pain intensity and unpleasantness significantly improved with time for the MedExT group compared with that of the control group, respectively (intensity P=0.0008; unpleasantness P=0.0022).
Conclusion: . Overall, 4 weeks of MedExT produced suggestive between-group trends for disability, significant between-group differences for measures of pain, and significant within-group increases in mindfulness.
Polaski AG, Phelps AL, Smith TJ, Helm ER, Morone NE, Szucs KA, Kostek MC, BJ KolberC
January 2021
Progress in Neurobiology
Left and right hemispheric lateralization of the amygdala in pain
Hemispheric asymmetries within the brain have been identified across taxa and have been extensively studied since the early 19th century. Here, we discuss lateralization of a brain structure, the amygdala, and how this lateralization is reshaping how we understand the role of the amygdala in pain processing. The amygdala is an almond-shaped, bilateral brain structure located within the limbic system. Historically, the amygdala was known to have a role in the processing of emotions and attaching emotional valence to memories and other experiences. The amygdala has been extensively studied in fear conditioning and affect but recently has been shown to have an important role in processing noxious information and impacting pain. The amygdala is composed of multiple nuclei; of special interest is the central nucleus of the amygdala (CeA). The CeA receives direct nociceptive inputs from the parabrachial nucleus (PBN) through the spino-parabrachio-amygdaloid pathway as well as more highly processed cortical and thalamic input via the lateral and basolateral amygdala. Although the amygdala is a bilateral brain region, most data investigating the amygdala’s role in pain have been generated from the right CeA, which has an overwhelmingly pro-nociceptive function across pain models. The left CeA has often been characterized to have no effect on pain modulation, a dampened pro-nociceptive function, or most recently an anti-nociceptive function. This review explores the current literature on CeA lateralization and the hemispheres’ respective roles in the processing and modulation of different forms of pain.
Allen HG, Bobnar HG, BJ KolberC
January 2021
Frontiers in Cell and Developmental Biology
Peripheral nerve injury induces a myriad of immune-derived symptoms that negatively impacts pain, depression, and overall quality of life. Neuroimmune differences underlie sexual dimorphisms in various pain states. The innate immune system is a source of these sex differences, which promotes inflammation and pro-nociception through bidirectional signaling with the nervous system. Spatiotemporal interactions between leukocytes and sensory neurons could hold the key to explain ascribed differences between sexes. To date, studies have found it difficult to display these interactions. We are poised to answer important questions regarding the recruitment of peripheral leukocytes to key tissues of the pain system, the dorsal root ganglia (DRG) and sciatic nerve after nerve injury. We optically clear whole DRGs and sciatic nerves and concomitantly use multi-photon microscopy and transgenic reporter lines, to visualize leukocyte dynamics involved in neuropathic pain development following nerve injury. We observed robust sexual dimorphisms in leukocyte recruitment to the lumbar DRGs after nerve injury. We also assessed immune cell size and morphology to understand activation states in the context of nervous tissue inflammation. The altered mechanisms by which the male and female immune systems respond to nerve injury are still topics of further research, however; the continued use of next-generation imaging with advanced whole tissue image analysis remains an important tool in understanding the reciprocal interactions between neuronal and non-neuronal cells.
Szabo-Pardi, T.A., Syed, U., Castillo, Z.W., Burton M.D.
January 2021
Journal of the Endocrine Society
Homeostatic Regulation of Estrus Cycle of Young Female Mice on Western Diet
The etiology of reproductive disorders correlates with weight gain in patients, but the link between reproduction, diet, and weight has been difficult to translate in rodents. As rates of childhood obesity and reproductive disorders increase, the need to study the effects of weight and diet on adolescent females is key. Previous studies show that female mice are resistant to high-fat diet-induced weight gain, but the mechanisms are unclear. Literature also suggests that ovarian function is essential to resistance in weight gain, as an ovariectomy leads to a weight-gaining phenotype similar to male mice on a high-fat diet. However, reproductive changes that occur in adolescent mice on high-fat diet have not been assessed. Here, we show that regulation of the estrus cycle via progesterone is critical to metabolic homeostasis in female mice on a high-fat diet. Female mice were put on high-fat diet or control diet for 12 weeks starting at 4 weeks of age. Every 4 weeks, their estrus cycle was tracked and fasting glucose was measured. We found that after 4 weeks on high-fat diet, there was no difference in weight between groups, but an increase in time spent in proestrus and estrus in mice on high-fat diet and an increase in serum progesterone during proestrus. These results show that intact females modulate their estrus cycle in response to a high-fat diet as a mechanism of homeostatic regulation of body weight, protecting them from metabolic abnormalities. Understanding the mechanisms behind this protection may yield therapeutic opportunities for treatment of reproductive disorders in adolescent female patients.
Lenert, M.E., Chaparro, M.M., Burton, M.D.
Jan 2021
Pain Reports
SARS-CoV-2 is a novel coronavirus that infects cells through the angiotensin-converting enzyme 2 receptor, aided by proteases that prime the spike protein of the virus to enhance cellular entry. Neuropilin 1 and 2 (NRP1 and NRP2) act as additional viral entry factors. SARS-CoV-2 infection causes COVID-19 disease. There is now strong evidence for neurological impacts of COVID-19, with pain as an important symptom, both in the acute phase of the disease and at later stages that are colloquially referred to as “long COVID.” In this narrative review, we discuss how COVID-19 may interact with the peripheral nervous system to cause pain in the early and late stages of the disease. We begin with a review of the state of the science on how viruses cause pain through direct and indirect interactions with nociceptors. We then cover what we currently know about how the unique cytokine profiles of moderate and severe COVID-19 may drive plasticity in nociceptors to promote pain and worsen existing pain states. Finally, we review evidence for direct infection of nociceptors by SARS-CoV-2 and the implications of this potential neurotropism. The state of the science points to multiple potential mechanisms through which COVID-19 could induce changes in nociceptor excitability that would be expected to promote pain, induce neuropathies, and worsen existing pain states.
McFarland AJ, Yousuf MS, Shiers S, Price TJ
Jan 2021
Pharmacological Reviews
Pharmacological Manipulation of Translation as a Therapeutic Target for Chronic Pain
Dysfunction in regulation of mRNA translation is an increasingly recognized characteristic of many diseases and disorders, including cancer, diabetes, autoimmunity, neurodegeneration, and chronic pain. Approximately 50 million adults in the United States experience chronic pain. This economic burden is greater than annual costs associated with heart disease, cancer, and diabetes combined. Treatment options for chronic pain are inadequately efficacious and riddled with adverse side effects. There is thus an urgent unmet need for novel approaches to treating chronic pain. Sensitization of neurons along the nociceptive pathway causes chronic pain states driving symptoms that include spontaneous pain and mechanical and thermal hypersensitivity. More than a decade of preclinical research demonstrates that translational mechanisms regulate the changes in gene expression that are required for ongoing sensitization of nociceptive sensory neurons. This review will describe how key translation regulation signaling pathways, including the integrated stress response, mammalian target of rapamycin, AMP-activated protein kinase (AMPK), and mitogen-activated protein kinase-interacting kinases, impact the translation of different subsets of mRNAs. We then place these mechanisms of translation regulation in the context of chronic pain states, evaluate currently available therapies, and examine the potential for developing novel drugs. Considering the large body of evidence now published in this area, we propose that pharmacologically manipulating specific aspects of the translational machinery may reverse key neuronal phenotypic changes causing different chronic pain conditions. Therapeutics targeting these pathways could eventually be first-line drugs used to treat chronic pain disorders. SIGNIFICANCE STATEMENT: Translational mechanisms regulating protein synthesis underlie phenotypic changes in the sensory nervous system that drive chronic pain states. This review highlights regulatory mechanisms that control translation initiation and how to exploit them in treating persistent pain conditions. We explore the role of mammalian/mechanistic target of rapamycin and mitogen-activated protein kinase-interacting kinase inhibitors and AMPK activators in alleviating pain hypersensitivity. Modulation of eukaryotic initiation factor 2α phosphorylation is also discussed as a potential therapy. Targeting specific translation regulation mechanisms may reverse changes in neuronal hyperexcitability associated with painful conditions.
Yousuf MS, Shiers S, Sahn JJ, Price TJ
Jan 2021
Nature Communications
The vagus nerve supports diverse autonomic functions and behaviors important for health and survival. To understand how specific components of the vagus contribute to behaviors and long-term physiological effects, it is critical to modulate their activity with anatomical specificity in awake, freely behaving conditions using reliable methods. Here, we introduce an organ-specific scalable, multimodal, wireless optoelectronic device for precise and chronic optogenetic manipulations in vivo. When combined with an advanced, coil-antenna system and a multiplexing strategy for powering 8 individual homecages using a single RF transmitter, the proposed wireless telemetry enables low cost, high-throughput, and precise functional mapping of peripheral neural circuits, including long-term behavioral and physiological measurements. Deployment of these technologies reveals an unexpected role for stomach, non-stretch vagal sensory fibers in suppressing appetite and demonstrates the durability of the miniature wireless device inside harsh gastric conditions.
Kim WS, Hong S, Gamero M, Jeevakumar V, Smithhart C, Price TJ, Palmiter R, Campos C, Park SI
2020
December 2020
eNeuro
TLR4 signaling selectively and directly promotes CGRP release from vagal afferents
There has been a long-standing debate regarding the role of peripheral afferents in mediating rapid-onset anorexia among other responses elicited by peripheral inflammatory insults. Thus, the current study assessed the sufficiency of peripheral afferents expressing toll-like receptor 4 (TLR4) to the initiation of the anorexia caused by peripheral bacterial lipopolysaccharide (LPS). We generated a Tlr4 null (Tlr4LoxTB) mouse in which Tlr4 expression is globally disrupted by a loxP-flanked transcription blocking (TB) cassette. This novel mouse model allowed us to restore the endogenous TLR4 expression in specific cell types. Using Zp3-Cre and Nav1.8-Cre mice, we produced mice that express TLR4 in all cells (Tlr4LoxTB X Zp3-Cre) and in peripheral afferents (Tlr4LoxTB X Nav1.8-Cre), respectively. We validated the Tlr4LoxTB mice, which were phenotypically identical to previously reported global TLR4 knock-out mice. Contrary to our expectations, the administration of LPS did not cause rapid-onset anorexia in mice with Nav1.8-restricted TLR4. The later result prompted us to identify Tlr4-expressing vagal afferents using in situ hybridization (ISH). In vivo, we found that Tlr4 mRNA was primarily enriched in vagal Nav1.8 afferents located in the jugular ganglion that co-expressed calcitonin gene-related peptide (CGRP). In vitro, the application of LPS to cultured Nav1.8-restricted TLR4 afferents was sufficient to stimulate the release of CGRP. In summary, we demonstrated using a new mouse model that vagally-expressed TLR4 is selectively involved in stimulating the release of CGRP but not in causing anorexia.
Jia, L., Lee, S., Tierney, J.A.+, Elmquist, J.K., Burton, M.D., Gautron, L.
December 2020
Soft Matter
Stimuli-responsive engineered living materials
Stimuli-responsive materials are able to undergo controllable changes in materials properties in response to external cues. Increasing efforts have been directed towards building materials that mimic the responsive nature of biological systems. Nevertheless, limitations remain surrounding the way these synthetic materials interact and respond to their environment. In particular, it is difficult to synthesize synthetic materials that respond with specificity to poorly differentiated (bio)chemical and weak physical stimuli. The emerging area of engineered living materials (ELMs) includes composites that combine living cells and synthetic materials. ELMs have yielded promising advances in the creation of stimuli-responsive materials that respond with diverse outputs in response to a broad array of biochemical and physical stimuli. This review describes advances made in the genetic engineering of the living component and the processing-property relationships of stimuli-responsive ELMs. Finally, the implementation of stimuli-responsive ELMs as environmental sensors, biomedical sensors, drug delivery vehicles, and soft robots is discussed.
Rivera-Tarazona LK, Campbell ZT, Ware TH
November 2020
Neurology of Aging
Translation regulation in the context of aged-associated inflammation and behavioral impairments is not well characterized. Aged individuals experience lower life quality due to behavioral impairments. In this study, we used young and aged transgenic mice that are unable to activate the cap-binding protein, eukaryotic translation initiation factor 4E (eIF4E) to examine the role of protein translation control in aging, memory, depression, and anxiety. To determine how products of cap-dependent translation play a permissive role in aged-associated inflammation, we assessed levels of pro-inflammatory cytokines in various brain regions involved in the above-mentioned behaviors. We found that functional eIF4E is not necessary for age-related deficits in spatial and short-term memory but is important for depressive and anxiety-like behavior and this is correlated with pro-inflammatory cytokines in discrete brain regions. Thus, we have begun to elucidate a role for eIF4E phosphorylation in the context of aged-related behavioral impairments and chronic low-grade inflammation that may help identify novel immune modulators for therapeutic targets and decrease the burden of self-care among the geriatric population.
Mody, P.H., Santos, N.L., Lenert, M.E., Barron, L.R., Nottingham, B.L., Burton, M.D.
November 2020
Molecular Biology of the Cell
Scientific societies aiming to foster inclusion of scientists from underrepresented (UR) backgrounds among their membership often delegate primary responsibility for this goal to a diversity-focused committee. The National Science Foundation has funded the creation of the Alliance to Catalyze Change for Equity in STEM Success (ACCESS), a meta-organization bringing together representatives from several such STEM society committees to serve as a hub for a growing community of practice. Our goal is to coordinate efforts to advance inclusive practices by sharing experiences and making synergistic discoveries about what works. ACCESS has analyzed the approaches by which member societies have sought to ensure inclusivity through selection of annual meeting speakers. Here we discuss how inclusive speaker selection fosters better scientific environments for all and identify challenges and promising practices for societies striving to maximize inclusivity of speakers in their scientific programming.
Segarra VA, Primus C, Unguez GA, Edwards A, Etson C, Flores SC, Fry C, Guillory AN, Ingram SL, Lawson M, McGee R, Paxson S, Phelan L, Suggs K, Vega LR, Vuong E, Havran JC, Leon A, Burton MD, Lujan JL, Ramirez-Alvarado M.
November 2020
Journal of Neuroscience
The Neuroimmunology of Chronic Pain: From Rodents to Humans
Chronic pain, encompassing conditions, such as low back pain, arthritis, persistent post-surgical pain, fibromyalgia, and neuropathic pain disorders, is highly prevalent but remains poorly treated. The vast majority of therapeutics are directed solely at neurons, despite the fact that signaling between immune cells, glia, and neurons is now recognized as indispensable for the initiation and maintenance of chronic pain. This review highlights recent advances in understanding fundamental neuroimmune signaling mechanisms and novel therapeutic targets in rodent models of chronic pain. We further discuss new technological developments to study, diagnose, and quantify neuroimmune contributions to chronic pain in patient populations.
Grace P.M., Tawfik, V.L., Svensson, C.I., Burton, M.D., Loggia, M.L., Hutchinson, M.R
November 2020
Cephalalgia
De novo protein synthesis is necessary for priming in preclinical models of migraine
Background: Migraine attacks are often triggered by normally innocuous stimuli, suggesting that sensitization within the nervous system is present. One mechanism that may contribute to neuronal sensitization in this context is translation regulation of new protein synthesis. The goal of this study was to determine whether protein synthesis contributes to behavioral responses and priming in preclinical models of migraine.
Methods: Mice received a dural injection of interleukin-6 in the absence or presence of the protein synthesis inhibitor anisomycin or the translation initiation inhibitor 4EGI-1 and were tested for facial hypersensitivity. Upon returning to baseline, mice were given a second, non-noxious dural injection of pH 7.0 to test for priming. Additionally, eIF4ES209Amice lacking phosphorylation of mRNA cap-binding protein eIF4E received dural interleukin-6 or were subjected to repeated restraint stress and then tested for facial hypersensitivity. After returning to baseline, mice were given either dural pH 7.0 or a systemic sub-threshold dose of the nitric oxide donor sodium nitroprusside and tested for priming.
Results: Dural injection of interleukin-6 in the presence of anisomycin or 4EGI-1 or in eIF4ES209Amice resulted in the partial attenuation of acute facial hypersensitivity and complete block of hyperalgesic priming. Additionally, hyperalgesic priming following repeated restraint stress was blocked in eIF4ES209Amice.
Conclusions: These studies show that de novo protein synthesis regulated by activity-dependent translation is critical to the development of priming in two preclinical models of migraine. This suggests that targeting the regulation of protein synthesis may be a novel approach for new migraine treatment strategies.
Lackovic J, Price TJ, Dussor G
November 2020
Pain
SARS-CoV-2 has created a global crisis. COVID-19, the disease caused by the virus, is characterized by pneumonia, respiratory distress, and hypercoagulation and can be fatal. An early sign of infection is loss of smell, taste, and chemesthesis-loss of chemical sensation. Other neurological effects of the disease have been described, but not explained. It is now apparent that many of these neurological effects (for instance joint pain and headache) can persist for at least months after infection, suggesting a sensory neuronal involvement in persistent disease. We show that human dorsal root ganglion (DRG) neurons express the SARS-CoV-2 receptor, angiotensin-converting enzyme 2 at the RNA and protein level. We also demonstrate that SARS-CoV-2 and coronavirus-associated factors and receptors are broadly expressed in human DRG at the lumbar and thoracic level as assessed by bulk RNA sequencing. ACE2 mRNA is expressed by a subset of nociceptors that express MRGPRD mRNA, suggesting that SARS-CoV-2 may gain access to the nervous system through entry into neurons that form free nerve endings at the outermost layers of skin and luminal organs. Therefore, DRG sensory neurons are a potential target for SARS-CoV-2 invasion of the peripheral nervous system, and viral infection of human nociceptors may cause some of the persistent neurological effects seen in COVID-19.
Shiers S, Ray PR, Wangzhou A, Sankaranarayanan, Esteves Tatsui C, Rhines LD, Li Y, Uhelski M, Dougherty PM, Price TJ
October 2020
Neurotherapeutics
A Highly Selective MNK Inhibitor Rescues Deficits Associated with Fragile X Syndrome in Mice
Fragile X syndrome (FXS) is the most common inherited source of intellectual disability in humans. FXS is caused by mutations that trigger epigenetic silencing of the Fmr1 gene. Loss of Fmr1 results in increased activity of the mitogen-activated protein kinase (MAPK) pathway. An important downstream consequence is activation of the mitogen-activated protein kinase interacting protein kinase (MNK). MNK phosphorylates the mRNA cap-binding protein, eukaryotic initiation factor 4E (eIF4E). Excessive phosphorylation of eIF4E has been directly implicated in the cognitive and behavioral deficits associated with FXS. Pharmacological reduction of eIF4E phosphorylation is one potential strategy for FXS treatment. We demonstrate that systemic dosing of a highly specific, orally available MNK inhibitor, eFT508, attenuates numerous deficits associated with loss of Fmr1 in mice. eFT508 resolves a range of phenotypic abnormalities associated with FXS including macroorchidism, aberrant spinogenesis, and alterations in synaptic plasticity. Key behavioral deficits related to anxiety, social interaction, obsessive and repetitive activities, and object recognition are ameliorated by eFT508. Collectively, this work establishes eFT508 as a potential means to reverse deficits associated with FXS.
Shukla T, de la Peña JB, Perish JM, Ploski JE, Stumpf CR, Webster KR, Thorn CA, Campbell ZT
October 2020
Pain
Next-generation transcriptomics in combination with imaging-based approaches have emerged as powerful tools for the characterization of dorsal root ganglion (DRG) neuronal subpopulations. The mouse DRG has been well characterized by many independently conducted studies with convergent findings, but few studies have directly compared expression of population markers between mouse and human. This is important because of our increasing reliance on the mouse as a preclinical model for translational studies. Although calcitonin gene-related peptide (CGRP) and P2X purinergic ion channel type 3 receptor (P2X3R) have been used to define peptidergic and nonpeptidergic nociceptor subpopulations, respectively, in mouse DRG, these populations may be different in other species. To directly test this, as well as a host of other markers, we used multiplex RNAscope in situ hybridization to elucidate the distribution of a multitude of unique and classic neuronal mRNAs in peptidergic (CGRP-expressing) and nonpeptidergic (P2X3R-expressing) nociceptor subpopulations in mouse and human DRG. We found a large overlapping CGRP and P2X3R neuronal subpopulation in human, lumbar DRG that was not present in mouse. We also found differential expression in a variety of mRNAs for transient receptor potential channels, cholinergic receptors, potassium channels, sodium channels, and other markers/targets. These data offer insights into the spatial and functional organization of neuronal cell subpopulations in the rodent and human DRG and support the idea that sensory system organizational principles are likely different between both species.
Shiers SI, Klein RM, Price TJ
October 2020
Biological Psychiatry
Background: There are clinically relevant sex differences in acute and chronic pain mechanisms, but we are only beginning to understand their mechanistic basis. Transcriptome analyses of rodent whole dorsal root ganglion (DRG) have revealed sex differences, mostly in immune cells. We examined the transcriptome and translatome of the mouse DRG with the goal of identifying sex differences.
Methods: We used translating ribosome affinity purification sequencing and behavioral pharmacology to test the hypothesis that in Nav1.8-positive neurons, most of which are nociceptors, translatomes would differ by sex.
Results: We found 80 genes with sex differential expression in the whole DRG transcriptome and 66 genes whose messenger RNAs were sex differentially actively translated (translatome). We also identified different motifs in the 3′ untranslated region of messenger RNAs that were sex differentially translated. In further validation studies, we focused on Ptgds, which was increased in the translatome of female mice. The messenger RNA encodes the prostaglandin PGD2 synthesizing enzyme. We observed increased PTGDS protein and PGD2 in female mouse DRG. The PTGDS inhibitor AT-56 caused intense pain behaviors in male mice but was only effective at high doses in female mice. Conversely, female mice responded more robustly to another major prostaglandin, PGE2, than did male mice. PTGDS protein expression was also higher in female cortical neurons, suggesting that DRG findings may be generalizable to other nervous system structures.
Conclusions: Our results demonstrate sex differences in nociceptor-enriched translatomes and reveal unexpected sex differences in one of the oldest known nociceptive signaling molecule families, the prostaglandins.
Tavares-Ferreira D, Ray PR, Sankaranarayanan I, Mejia GL, Wangzhou A, Shiers S, Uttarkar R, Megat S, Barragan-Iglesias P, Dussor G, Akopian AN, Price TJ
October 2020
Pharmacology and Therapeutics
Countermeasures for preventing and treating opioid overdose
The only medication available currently to prevent and treat opioid overdose (naloxone) was approved by the US Food and Drug Administration (FDA) nearly 50 years ago. Because of its pharmacokinetic and pharmacodynamic properties, naloxone has limited utility under some conditions and would not be effective to counteract mass casualties involving large-scale deployment of weaponized synthetic opioids. To address shortcomings of current medical countermeasures for opioid toxicity, a trans-agency scientific meeting was convened by the US National Institute of Allergy and Infectious Diseases/National Institutes of Health (NIAID/NIH) on August 6 and 7, 2019, to explore emerging alternative approaches for treating opioid overdose in the event of weaponization of synthetic opioids. The meeting was initiated by the Chemical Countermeasures Research Program (CCRP), was organized by NIAID, and was a collaboration with the National Institute on Drug Abuse/NIH (NIDA/NIH), the FDA, the Defense Threat Reduction Agency (DTRA), and the Biomedical Advanced Research and Development Authority (BARDA). This paper provides an overview of several presentations at that meeting that discussed emerging new approaches for treating opioid overdose, including the following: (1) intranasal nalmefene, a competitive, reversible opioid receptor antagonist with a longer duration of action than naloxone; (2) methocinnamox, a novel opioid receptor antagonist; (3) covalent naloxone nanoparticles; (4) serotonin (5-HT)1A receptor agonists; (5) fentanyl-binding cyclodextrin scaffolds; (6) detoxifying biomimetic “nanosponge” decoy receptors; and (7) antibody-based strategies. These approaches could also be applied to treat opioid use disorder.
France C, Ahern G, Averick S, Disney A, Enright H, Esmaeli-Azad B, Federico A, Gerak L, Husbands S, Kolber BJ, Lau E, Lao V, Maguire D, Malfatti M, Martinez G, Mayer B, Praventoni M, Sahibzada N, Skolnick P, Snyder E, Tomycz N, Valdez C, J ZapfC
October 2020
Brain, Behavior, and Immunity
The SARS-CoV-2 virus infects cells of the airway and lungs in humans causing the disease COVID-19. This disease is characterized by cough, shortness of breath, and in severe cases causes pneumonia and acute respiratory distress syndrome (ARDS) which can be fatal. Bronchial alveolar lavage fluid (BALF) and plasma from mild and severe cases of COVID-19 have been profiled using protein measurements and bulk and single cell RNA sequencing. Onset of pneumonia and ARDS can be rapid in COVID-19, suggesting a potential neuronal involvement in pathology and mortality. We hypothesized that SARS-CoV-2 infection drives changes in immune cell-derived factors that then interact with receptors expressed by the sensory neuronal innervation of the lung to further promote important aspects of disease severity, including ARDS. We sought to quantify how immune cells might interact with sensory innervation of the lung in COVID-19 using published data from patients, existing RNA sequencing datasets from human dorsal root ganglion neurons and other sources, and a genome-wide ligand-receptor pair database curated for pharmacological interactions relevant for neuro-immune interactions. Our findings reveal a landscape of ligand-receptor interactions in the lung caused by SARS-CoV-2 viral infection and point to potential interventions to reduce the burden of neurogenic inflammation in COVID-19 pulmonary disease. In particular, our work highlights opportunities for clinical trials with existing or under development rheumatoid arthritis and other (e.g. CCL2, CCR5 or EGFR inhibitors) drugs to treat high risk or severe COVID-19 cases.
Ray PR, Wangzhou A, Ghneim N, Yousuf MS, Paige C, Tavares-Ferreira D, Mwirigi JM, Shiers S, Sankaranarayanan I, McFarland AJ, Neerukonda SV, Davidson S, Dussor G, Burton MD, Price TJ.
October 2020
bioRxiv
Modulating the Blood-Brain Barrier by Light Stimulation of Molecular-Targeted Nanoparticles
The blood-brain barrier (BBB) tightly regulates the entry of molecules into the brain by tight junctions that seals the paracellular space and receptor-mediated transcytosis. It remains elusive to selectively modulate these mechanisms and to overcome BBB without significant neurotoxicity. Here we report that light stimulation of tight junction-targeted plasmonic nanoparticles selectively opens up the paracellular route to allow diffusion through the compromised tight junction and into the brain parenchyma. The BBB modulation does not impair vascular dynamics and associated neurovascular coupling, or cause significant neural injury. It further allows antibody and adeno-associated virus delivery into local brain regions. This novel method offers the first evidence of selectively modulating BBB tight junctions and opens new avenues for therapeutic interventions in the central nervous system.
Li, X., Vemireddy, V., Cai, Q., Xiong, H., Kang, P., Li, X, Giannotta, M., Hayenga H., Pan, E., Sirsi, S., Mateo, C., Kleinfeld, D., Greene, C., Campbell, M., Dejana E., Bachoo R. and Qin, Z.
October 2020
Clinical Pharmacology and Therapeutics
Countermeasures for preventing and treating opioid overdose.
The only medication available currently to prevent and treat opioid overdose (naloxone) was approved by the US Food and Drug Administration (FDA) nearly 50 years ago. Because of its pharmacokinetic and pharmacodynamic properties, naloxone has limited utility under some conditions and would not be effective to counteract mass casualties involving large-scale deployment of weaponized synthetic opioids. To address shortcomings of current medical countermeasures for opioid toxicity, a trans-agency scientific meeting was convened by the US National Institute of Allergy and Infectious Diseases/National Institutes of Health (NIAID/NIH) on August 6 and 7, 2019, to explore emerging alternative approaches for treating opioid overdose in the event of weaponization of synthetic opioids. The meeting was initiated by the Chemical Countermeasures Research Program (CCRP), was organized by NIAID, and was a collaboration with the National Institute on Drug Abuse/NIH (NIDA/NIH), the FDA, the Defense Threat Reduction Agency (DTRA), and the Biomedical Advanced Research and Development Authority (BARDA). This paper provides an overview of several presentations at that meeting that discussed emerging new approaches for treating opioid overdose, including the following: (1) intranasal nalmefene, a competitive, reversible opioid receptor antagonist with a longer duration of action than naloxone; (2) methocinnamox, a novel opioid receptor antagonist; (3) covalent naloxone nanoparticles; (4) serotonin (5-HT)1A receptor agonists; (5) fentanyl-binding cyclodextrin scaffolds; (6) detoxifying biomimetic “nanosponge” decoy receptors; and (7) antibody-based strategies. These approaches could also be applied to treat opioid use disorder
Charles P. France, Gerard P. Ahern, Saadyah Averick, Alex Disney, Heather A. Enright, Babak Esmaeli-Azad, Arianna Federico, Lisa R. Gerak, Stephen M. Husbands, Benedict Kolber, Edmond Y. Lau, Victoria Lao, David R. Maguire, Michael A. Malfatti, Girardo Martinez, Brian P. Mayer, Marco Pravetoni, Niaz Sahibzada, Phil Skolnick, Evan Y. Snyder, Nestor Tomycz, Carlos A. Valdez, Jim Zapf
September 2020
Pain
Rudjito, R., Agalave, N.M., Farinotti, A.B., Lundback, P.L., Szabo-Pardi, T.A., Price,T.J., Harris, H.E., Burton, M.D., Svensson, C.I.
September 2020
Pain
IL-5 mediates monocyte phenotype and pain outcomes in fibromyalgia
Fibromyalgia (FM) is characterized by widespread chronic pain, fatigue, and somatic symptoms. The influence of phenotypic changes in monocytes on symptoms associated with FM is not fully understood. The primary aim of this study was to take a comprehensive whole-body to molecular approach in characterizing relationships between monocyte phenotype and FM symptoms in relevant clinical populations. Lipopolysaccharide-evoked and spontaneous secretion of IL-5 and other select cytokines from circulating monocytes was higher in women with FM compared to women without pain. In addition, greater secretion of IL-5 was significantly associated with pain and other clinically relevant psychological and somatic symptoms of FM. Furthermore, higher levels of pain and pain-related symptoms were associated with a lower percentage of intermediate monocytes (CD14++/CD16+) and a greater percentage of nonclassical monocytes (CD14+/CD16++) in women with FM. Based on findings from individuals with FM, we examined the role of IL-5, an atypical cytokine secreted from monocytes, in an animal model of widespread muscle pain. Results from the animal model show that IL-5 produces analgesia and polarizes monocytes toward an anti-inflammatory phenotype (CD206+). Taken together, our data suggest that monocyte phenotype and their cytokine profiles are associated with pain-related symptoms in individuals with FM. Furthermore, our data show that IL-5 has a potential role in analgesia in an animal model of FM. Thus, targeting anti-inflammatory cytokines such as IL-5 secreted by circulating leukocytes could serve as a promising intervention to control pain and other somatic symptoms associated with FM.
Merriwether, E.N., Agalave, N.M., Dailey, D.L., Rakel, B.A., Kokler, S.J., Lenert, M.E.+, Spagnola, W.H., Lu, Y., Geasland, K.M., Allen, LA.H., Burton, M.D., Sluka, K.A.
September 2020
Scientific Reports
Transcriptomic sex differences in sensory neuronal populations of mice
Many chronic pain conditions show sex differences in their epidemiology. This could be attributed to sex-dependent differential expression of genes (DEGs) involved in nociceptive pathways, including sensory neurons. This study aimed to identify sex-dependent DEGs in estrous female versus male sensory neurons, which were prepared by using different approaches and ganglion types. RNA-seq on non-purified sensory neuronal preparations, such as whole dorsal root ganglion (DRG) and hindpaw tissues, revealed only a few sex-dependent DEGs. Sensory neuron purification increased numbers of sex-dependent DEGs. These DEG sets were substantially influenced by preparation approaches and ganglion types [DRG vs trigeminal ganglia (TG)]. Percoll-gradient enriched DRG and TG neuronal fractions produced distinct sex-dependent DEG groups. We next isolated a subset of sensory neurons by sorting DRG neurons back-labeled from paw and thigh muscle. These neurons have a unique sex-dependent DEG set, yet there is similarity in biological processes linked to these different groups of sex-dependent DEGs. Female-predominant DEGs in sensory neurons relate to inflammatory, synaptic transmission and extracellular matrix reorganization processes that could exacerbate neuro-inflammation severity, especially in TG. Male-selective DEGs were linked to oxidative phosphorylation and protein/molecule metabolism and production. Our findings catalog preparation-dependent sex differences in neuronal gene expressions in sensory ganglia.
Mecklenberg J, Zou Y, Wangzhou A, Garcia D, Lai Z, Tumanov A, Dussor G, Price TJ, Akopian AN
August 2020
Pain
High mobility group box 1 protein (HMGB1) is increasingly regarded as an important player in the spinal regulation of chronic pain. Although it has been reported that HMGB1 induces spinal glial activation in a Toll-like receptor (TLR)4-dependent fashion, the aspect of sexual dimorphisms has not been thoroughly addressed. Here, we examined whether the action of TLR4-activating, partially reduced disulfide HMGB1 on microglia induces nociceptive behaviors in a sex-dependent manner. We found disulfide HMGB1 to equally increase microglial Iba1 immunoreactivity in lumbar spinal dorsal horn in male and female mice, but evoke higher cytokine and chemokine expression in primary microglial culture derived from males compared to females. Interestingly, TLR4 ablation in myeloid-derived cells, which include microglia, only protected male mice from developing HMGB1-induced mechanical hypersensitivity. Spinal administration of the glial inhibitor, minocycline, with disulfide HMGB1 also prevented pain-like behavior in male mice. To further explore sex difference, we examined the global spinal protein expression using liquid chromatography-mass spectrometry and found several antinociceptive and anti-inflammatory proteins to be upregulated in only male mice subjected to minocycline. One of the proteins elevated, alpha-1-antitrypsin, partially protected males but not females from developing HMGB1-induced pain. Targeting downstream proteins of alpha-1-antitrypsin failed to produce robust sex differences in pain-like behavior, suggesting that several proteins identified by liquid chromatography-mass spectrometry are required to modulate the effects. Taken together, the current study highlights the importance of mapping sex dimorphisms in pain mechanisms and point to processes potentially involved in the spinal antinociceptive effect of microglial inhibition in male mice.
Agalave, N.M., Rudjito, R., Farinotti, A.B., Khoonsari, P.E., Sandor, K., Nomura, Y., Szabo-Pardi, T.A., Urbina, C.M., Palada, V., Price, T.J., Harris, H.E., Burton, M.D., Kultima, K., Svensson, C.I.
August 2020
Nature Communications
Somatic sensation is defined by the existence of a diversity of primary sensory neurons with unique biological features and response profiles to external and internal stimuli. However, there is no coherent picture about how this diversity of cell states is transcriptionally generated. Here, we use deep single cell analysis to resolve fate splits and molecular biasing processes during sensory neurogenesis in mice. Our results identify a complex series of successive and specific transcriptional changes in post-mitotic neurons that delineate hierarchical regulatory states leading to the generation of the main sensory neuron classes. In addition, our analysis identifies previously undetected early gene modules expressed long before fate determination although being clearly associated with defined sensory subtypes. Overall, the early diversity of sensory neurons is generated through successive bi-potential intermediates in which synchronization of relevant gene modules and concurrent repression of competing fate programs precede cell fate stabilization and final commitment.
Faure L., Wang Y., Kastriti M.E., Fontanet P., Cheung K., Petitpré C., Wu H., Rung K., Croci L., Landy M.A., Lai H.C., Consalez G.G., de Chevigny A., Lallemend F., Adameyko I., Hadjab S.
August 2020
Science
Neuropathic pain, which is pain that arises from injury or disease affecting the somatosensory nervous system, affects millions of people with devastating consequences to their well-being. Available therapeutics have limited efficacy, and the underlying mechanisms governing the persistence of this disorder are mysterious. On page 842 of this issue, Marvaldi et al. (1) reveal that the nuclear import protein, importin α3, plays a crucial role in maintaining neuropathic pain months after a peripheral nerve injury in mice. Their findings demonstrate that activator protein 1 (AP1) family transcription factors require this nuclear transport complex for entrance to the sensory neuronal nucleus, pointing to a defined set of drug targets for the potential disruption of persistent neuropathic pain. An implication of the findings is that even very long-lasting neuropathic pain can be disrupted with disease-modifying therapeutics.
Yousuf MS, Price TJ
August 2020
Journal of Neuroscience
Many clinical and preclinical studies report higher prevalence and severity of chronic pain in females. We used hyperalgesic priming with interleukin 6 (IL-6) priming and PGE2 as a second stimulus as a model for pain chronicity. Intraplantar IL-6 induced hypersensitivity was similar in magnitude and duration in both males and females, while both paw and intrathecal PGE2hypersensitivity was more persistent in females. This difference in PGE2 response was dependent on both circulating estrogen and translation regulation signaling in the spinal cord. In males, the duration of hypersensitivity was regulated by testosterone. Since the prolactin receptor (Prlr) is regulated by reproductive hormones and is female-selectively activated in sensory neurons, we evaluated whether Prlr signaling contributes to hyperalgesic priming. Using ΔPRL, a competitive Prlr antagonist, and a mouse line with ablated Prlr in the Nav1.8 sensory neuronal population, we show that Prlr in sensory neurons is necessary for the development of hyperalgesic priming in female, but not male, mice. Overall, sex-specific mechanisms in the initiation and maintenance of chronic pain are regulated by the neuroendocrine system and, specifically, sensory neuronal Prlr signaling.SIGNIFICANCE STATEMENT Females are more likely to experience chronic pain than males, but the mechanisms that underlie this sex difference are not completely understood. Here, we demonstrate that the duration of mechanical hypersensitivity is dependent on circulating sex hormones in mice, where estrogen caused an extension of sensitivity and testosterone was responsible for a decrease in the duration of the hyperalgesic priming model of chronic pain. Additionally, we demonstrated that prolactin receptor expression in Nav1.8+ neurons was necessary for hyperalgesic priming in female, but not male, mice. Our work demonstrates a female-specific mechanism for the promotion of chronic pain involving the neuroendrocrine system and mediated by sensory neuronal prolactin receptor.
Paige C, Barba-Escobedo PA, Mecklenberg J, Patil M, Goffin V, Grattan DR, Dussor G, Akopian AN, Price TJ
August 2020
Pain
Molecular, circuit, and anatomical changes in the prefrontal cortex in chronic pain
The prefrontal cortex undergoes functional and structural reorganization in chronic pain conditions in both rodents and humans. We provide an illustrated overview of the molecular, functional, and connectivity pathology occurring in the prefrontal cortex in chronic pain states.
Shiers S, Price TJ
August 2020
Journal of Neurochemistry
Extrasynaptic α5 -subunit containing GABAA (α5 -GABAA) receptors participate in chronic pain. Previously, we reported a sex difference in the action of α5 -GABAA receptors in dysfunctional pain. However, the underlying mechanisms remain unknown. The aim of this study was to examine this sexual dimorphism in neuropathic rodents and the mechanisms involved. Female and male Wistar rats or ICR mice were subjected to nerve injury followed by α5 -GABAA receptor inverse agonist intrathecal administration, L-655,708. The drug produced an antiallodynic effect in nerve-injured female rats and mice, and a lower effect in males. We hypothesized that changes in α5 -GABAA receptor, probably influenced by hormonal and epigenetic status, might underlie this sex difference. Thus, we performed qPCR and western blot. Nerve injury increased α5 -GABAA mRNA and protein in female dorsal root ganglia (DRG) and decreased them in DRG and spinal cord of males. To investigate the hormonal influence over α5 -GABAA receptor actions, we performed nerve injury to ovariectomized rats and reconstituted them with 17β-estradiol (E2). Ovariectomy abrogated L-655,708 antiallodynic effect and E2 restored it. Ovariectomy decreased α5 -GABAA receptor and estrogen receptor α protein in DRG of neuropathic female rats, while E2 enhanced them. Since DNA methylation might contribute to α5 -GABAA receptor down-regulation in males, we examined CpG island DNA methylation of α5 -GABAA receptor coding gene through pyrosequencing. Nerve injury increased methylation in male, but not female rats. Pharmacological inhibition of DNA methyltransferases increased α5 -GABAA receptor and enabled L-655,708 antinociceptive effect in male rats. These results suggest that α5 -GABAA receptor is a suitable target to treat chronic pain in females.
Franco-Enzástiga U, García G, Murbartián J, González-Barrios R, Salinas-Abarca AB, Sánchez-Hernández B, Tavares-Ferreira D, Herrera LA, Barragán-Iglesias P, Delgado-Lezama R, Price TJ, Granados-Soto V
August 2020
Journal of Neuroscience Research
Thousands of individuals die each year from opioid‐related overdoses. While naloxone (Narcan®) is currently the most widely employed treatment to reverse opioid toxicity, high or repeated doses of this antidote often lead to precipitated opioid withdrawal (POW). We hypothesized that a slow linear release of naloxone from a nanoparticle would induce fewer POW symptoms compared to high‐dose free naloxone. First, we measured the acute impact of covalent naloxone nanoparticles (Nal‐cNPs) on morphine‐induced antinociception in the hotplate test. We found that Nal‐cNP treatment blocked the antinociceptive effect of morphine within 15 min of administration. Next, we tested the impact of Nal‐cNPs on POW symptoms in male morphine‐dependent mice. To induce morphine dependence, mice were treated with 5 mg/kg morphine (or saline) twice‐daily for six consecutive days. On day 7 mice received 5 mg/kg morphine (or saline) injections 2 hr prior to receiving treatment of either unmodified free naloxone, a high or low dose of Nal‐cNP, empty nanoparticle (cNP‐empty), or saline. Behavior was analyzed for 0–6 hr followed by 24 and 48 hr time points after treatment. As expected, free naloxone induced a significant increase in POW behavior in morphine‐dependent mice compared to saline‐treated mice upon free naloxone administration. In comparison, reduced POW behavior was observed with both doses of Nal‐cNP. Side effects of Nal‐cNP on locomotion and fecal boli production were measured, and no significant side effects were observed. Overall, our data show that sustained release of naloxone from a covalent nanoparticle does not induce severe POW symptoms in morphine‐dependent mice.
Lakeisha A Lewter, Marisa C Johnson, Anny C Treatf, Andrew J Kassick, Saadyah Averick, Benedict J Kolber
August 2020
Pain
Sex and cell-dependent contribution of peripheral HMGB1 and TLR4 in arthritis-induced pain
Spinal high mobility group box 1 protein (HMGB1) plays crucial roles in arthritis-induced pain, however the involvement of peripheral HMGB1 has not been examined previously. In this study, we addressed the role of peripheral HMGB1 and explored if sex contributes differentially to nociception in arthritis. We found Hmgb1 expression to be elevated in the ankle joints of male and female mice subjected to collagen antibody-induced arthritis (CAIA). Blocking the action of peripheral HMGB1, however, only reversed CAIA-induced hypersensitivity in males. Intra-articular injection of the toll-like receptor (TLR)4-activating, partially reduced disulfide, but not the fully reduced all-thiol, HMGB1 evoked mechanical hypersensitivity in both sexes. A sex-dependent temporal profile in expression of inflammatory factors in the ankle joint was observed in response to intra-articular injection of disulfide HMGB1, with male mice showing a delayed, yet longer lasting increase in mRNA levels for several of the investigated factors. Intra-articular HMGB1 did not induce cellular infiltration in the ankle joint suggesting its action on tissue resident cells. To further explore possible sex differences in cellular involvement, we used the macrophage inhibitor, minocycline, and mice with specific TLR4 depletion in myeloid cells or nociceptors. We found that inhibition of resident macrophages attenuated HMGB1-induced pain-like behavior only in male mice. Interestingly, while the contribution of TLR4 on myeloid cells to nociception was minimal in females compared to males, TLR4 on nociceptors are important for HMGB1-induced pain in both sexes. Collectively, our work highlights sex- and cellular location-dependent roles of HMGB1 and TLR4 in peripheral pain mechanisms.
Rudjito, Resti; Agalave, Nilesh M; Farinotti, Alex Bersellini; Lundbäck, Peter; Szabo-Pardi, Thomas; Price, Theodore J; Harris, Helena E; Burton, Michael D; Svensson, Camilla I
August 2020
Pain
Sex dependent role of microglia in disulfide HMGB1-mediated mechanical hypersensitivity
High mobility group box 1 protein (HMGB1) is increasingly regarded as an important player in the spinal regulation of chronic pain. While it has been reported that HMGB1 induces spinal glial activation in a Toll-like receptor (TLR)4-dependent fashion, the aspect of sexual dimorphisms has not been thoroughly addressed. Here, we examined whether the action of TLR4-activating, partially reduced disulfide HMGB1 on microglia induces nociceptive behaviors in a sex-dependent manner. We found disulfide HMGB1 to equally increase microglial Iba-1 immunoreactivity in lumbar spinal dorsal horn in male and female mice, but evoke higher cytokine and chemokine expression in primary microglial culture derived from males compared to females. Interestingly, TLR4 ablation in myeloid-derived cells, which include microglia, only protected male mice from developing HMGB1-induced mechanical hypersensitivity. Spinal administration of the glial inhibitor, minocycline, with disulfide HMGB1 also prevented pain-like behavior in male mice. To further explore sex difference, we examined the global spinal protein expression using liquid chromatography-mass spectrometry (LC-MS/MS) and found several antinociceptive and anti-inflammatory proteins to be upregulated in only male mice subjected to minocycline. One of the proteins elevated, alpha-1-antitrypsin, partially protected males but not females from developing HMGB1-induced pain. Targeting downstream proteins of alpha-1-antitrypsin failed to produce robust sex differences in pain-like behavior, suggesting that several proteins identified by LC-MS/MS are required to modulate the effects. Taken together, the current study highlights the importance of mapping sex dimorphisms in pain mechanisms and point to processes potentially involved in the spinal antinociceptive effect of microglial inhibition in male mice.
Agalave, Nilesh M; Rudjito, Resti; Farinotti, Alex Bersellini; Khoonsari, Payam Emami; Sandor, Katalin; Nomura, Yuki; Szabo-Pardi, Thomas A; Urbina, Carlos Morado; Palada, Vinko; Price, Theodore J; Harris, Helena E; Burton, Michael D; Kultima, Kim; Svensson, Camilla I
August 2020
Pain
SARS-CoV-2 has created a global crisis. COVID-19, the disease caused by the virus, is characterized by pneumonia, respiratory distress and hypercoagulation and can be fatal. An early sign of infection is loss of smell, taste and chemesthesis – loss of chemical sensation. Other neurological effects of the disease have been described, but not explained. It is now apparent that many of these neurological effects (for instance joint pain and headache) can persist for at least months after infection, suggesting a sensory neuronal involvement in persistent disease. We show that human dorsal root ganglion (DRG) neurons express the SARS-CoV-2 receptor, ACE2 at the RNA and protein level. We also demonstrate that SARS-CoV-2 and coronavirus-associated factors and receptors (SCARFs) are broadly expressed in human DRG at the lumbar and thoracic level as assessed by bulk RNA sequencing. ACE2 mRNA is expressed by a subset of nociceptors that express MRGPRD mRNA suggesting that SARS-CoV-2 may gain access to the nervous system through entry into neurons that form free-nerve endings at the outermost layers of skin and luminal organs. Therefore, DRG sensory neurons are a potential target for SARS-CoV-2 invasion of the peripheral nervous system and viral infection of human nociceptors may cause some of the persistent neurological effects seen in COVID-19.
Shiers, Stephanie; Ray, Pradipta R.; Wangzhou, Andi; Sankaranarayanan, Ishwarya; Tatsui, Claudio Esteves; Rhines, Laurence D.; Li, Yan; Uhelski, Megan L; Dougherty, Patrick M.; Price, Theodore
August 2020
Journal of Neuroscience Research
Thousands of individuals die each year from opioid-related overdoses. While naloxone (Narcan®) is currently the most widely employed treatment to reverse opioid toxicity, high or repeated doses of this antidote often lead to precipitated opioid withdrawal (POW). We hypothesized that a slow linear release of naloxone from a nanoparticle would induce fewer POW symptoms compared to high-dose free naloxone. First, we measured the acute impact of covalent naloxone nanoparticles (Nal-cNPs) on morphine-induced antinociception in the hotplate test. We found that Nal-cNP treatment blocked the antinociceptive effect of morphine within 15 min of administration. Next, we tested the impact of Nal-cNPs on POW symptoms in male morphine-dependent mice. To induce morphine dependence, mice were treated with 5 mg/kg morphine (or saline) twice-daily for six consecutive days. On day 7 mice received 5 mg/kg morphine (or saline) injections 2 hr prior to receiving treatment of either unmodified free naloxone, a high or low dose of Nal-cNP, empty nanoparticle (cNP-empty), or saline. Behavior was analyzed for 0-6 hr followed by 24 and 48 hr time points after treatment. As expected, free naloxone induced a significant increase in POW behavior in morphine-dependent mice compared to saline-treated mice upon free naloxone administration. In comparison, reduced POW behavior was observed with both doses of Nal-cNP. Side effects of Nal-cNP on locomotion and fecal boli production were measured and no significant side-effects were observed. Overall, our data show that sustained release of naloxone from a covalent nanoparticle does not induce severe POW symptoms in morphine-dependent mice.
Lewter LPD, Johnson MUG, Treat APD, Kassick AJ, Averick S, BJ KolberC
August 2020
Journal of Neuroscience
Many clinical and preclinical studies report higher prevalence and severity of chronic pain in females. We used hyperalgesic priming with interleukin 6 (IL-6) priming and PGE2 as a second stimulus as a model for pain chronicity. Intraplantar IL-6 induced hypersensitivity was similar in magnitude and duration in both males and females, while both paw and intrathecal PGE2 hypersensitivity was more persistent in females. This difference in PGE2 response was dependent on both circulating estrogen and translation regulation signaling in the spinal cord. In males, the duration of hypersensitivity was regulated by testosterone. Since the prolactin receptor (Prlr) is regulated by reproductive hormones and is female-selectively activated in sensory neurons, we evaluated whether Prlr signaling contributes to hyperalgesic priming. Using ΔPRL, a competitive Prlr antagonist, and a mouse line with ablated Prlr in the Nav1.8 sensory neuronal population, we show that Prlr in sensory neurons is necessary for the development of hyperalgesic priming in female but not male mice. Overall, sex-specific mechanisms in the initiation and maintenance of chronic pain are regulated by the neuroendocrine system and, specifically, sensory neuronal Prlr signaling.
Candler Paige, Priscilla A. Barba-Escobedo, Jennifer Mecklenburg, Mayur Patil, Vincent Gofin, David R. Grattan, Gregory Dussor, Armen N. Akopian and Theodore J. Price
July 2020
Geroscience
eIF4E phosphorylation modulates pain and neuroinflammation in the aged
The aged population has a higher probability of developing chronic pain from acute insults because of age-associated low-grade inflammation. Several emerging studies have shown a crucial role of cap-dependent translation in the development of chronic pain in young adult animals; however, its role in the aged has never been reported. Acute and chronic inflammatory responses, including pain, are altered over age, and understanding how cap-dependent translation can represent an important and druggable pathway is imperative for understanding its therapeutic potential. Here we have tested how an inflammatory stimulus, complete Freund’s adjuvant (CFA), affects spontaneous and evoked pain, as well as inflammation in young versus aged mice that lack functional cap-dependent translation machinery (eukaryotic translation initiation factor 4E (eIF4E)) compared with age-matched wild-type (WT) mice. Interestingly, we found that CFA-induced acute pain and inflammation are modulated by eIF4E phosphorylation in aged but not young animals. Aged transgenic animals showed attenuated paw temperature and inflammation, as well as a mitigation in the onset and quicker resolution in mechanical and thermal hypersensitivity. We found that levels of interleukin (IL)-1β and tumor necrosis factor (TNF)-α are elevated in dorsal root ganglia in aged WT and eIF4E transgenic groups, despite faster resolution of acute inflammation and pain in the aged eIF4E transgenic animals. We propose that these cytokines are important in mediating the observed behavioral responses in the young and represent an alternate pathway in the development of age-associated inflammation and behavioral consequences. These findings demonstrate that eIF4E phosphorylation can be a key target for treating inflammatory pain in the aged.
Mody P.H., Dos Santos N.L., Barron L.R., Price T.J., Burton M.D.
July 2020
Journal of Neurophysiology
Phosphorylation of the 5′ cap-binding protein eIF4E by MAPK-interacting kinases (MNK1/2) is important for nociceptor sensitization and the development of chronic pain. IL-6-induced dorsal root ganglion (DRG) nociceptor excitability is attenuated in mice lacking eIF4E phosphorylation, in MNK1/2-/- mice, and by the nonselective MNK1/2 inhibitor cercosporamide. Here, we sought to better understand the neurophysiological mechanisms underlying how IL-6 causes nociceptor excitability via MNK-eIF4E signaling using the highly selective MNK inhibitor eFT508. DRG neurons were cultured from male and female ICR mice, 4-7 wk old. DRG cultures were treated with vehicle, IL-6, eFT508 (pretreat) followed by IL-6, or eFT508 alone. Whole cell patch-clamp recordings were done on small-diameter neurons (20-30 pF) to measure membrane excitability in response to ramp depolarization. IL-6 treatment (1 h) resulted in increased action potential firing compared with vehicle at all ramp intensities, an effect that was blocked by pretreatment with eFT508. Basic membrane properties, including resting membrane potential, input resistance, and rheobase, were similar across groups. Latency to the first action potential in the ramp protocol was lower in the IL-6 group and rescued by eFT508 pretreatment. We also found that the amplitudes of T-type voltage-gated calcium channels (VGCCs) were increased in the DRG following IL-6 treatment, but not in the eFT508 cotreatment group. Our findings are consistent with a model wherein MNK-eIF4E signaling controls the translation of signaling factors that regulate T-type VGCCs in response to IL-6 treatment. Inhibition of MNK with eFT508 disrupts these events, thereby preventing nociceptor hyperexcitability.NEW & NOTEWORTHY In this study, we show that the MNK inhibitor and anti-tumor agent eFT508 (tomivosertib) is effective in attenuating IL-6 induced sensitization of dorsal root ganglion (DRG) nociceptors. Pretreatment with eFT508 in DRG cultures from mice helps mitigate the development of hyperexcitability in response to IL-6. Furthermore, our data reveal that the upregulation of T-type voltage-gated calcium channels following IL-6 application can be blocked by eFT508, implicating the MNK-eIF4E signaling pathway in membrane trafficking of ion channels.
Jeevakumar V, Al Sardar AK, Mohamed F, Smithhart CM, Price T, Dussor G.
July 2020
Progress in Neurobiology
Left and right hemispheric lateralization of the amygdala in pain
Hemispheric asymmetries within the brain have been identified across taxa and have been extensively studied since the early 19th century. Here, we discuss lateralization of a brain structure, the amygdala, and how this lateralization is reshaping how we understand the role of the amygdala in pain processing. The amygdala is an almond-shaped, bilateral brain structure located within the limbic system. Historically, the amygdala was known to have a role in the processing of emotions and attaching emotional valence to memories and other experiences. The amygdala has been extensively studied in fear conditioning and affect but recently has been shown to have an important role in processing noxious information and impacting pain. The amygdala is composed of multiple nuclei; of special interest is the central nucleus of the amygdala (CeA). The CeA receives direct nociceptive inputs from the parabrachial nucleus (PBN) through the spino-parabrachio-amygdaloid pathway as well as more highly processed cortical and thalamic input via the lateral and basolateral amygdala. Although the amygdala is a bilateral brain region, most data investigating the amygdala’s role in pain have been generated from the right CeA, which has an overwhelmingly pro-nociceptive function across pain models. The left CeA has often been characterized to have no effect on pain modulation, a dampened pro-nociceptive function, or most recently an anti-nociceptive function. This review explores the current literature on CeA lateralization and the hemispheres’ respective roles in the processing and modulation of different forms of pain.
Heather N Allen, Harley Bobnar, Benedict J Kolber
June 2020
Brain, Behavior, Immunity
The SARS-CoV-2 virus infects cells of the airway and lungs in humans causing the disease COVID-19. This disease is characterized by cough, shortness of breath, and in severe cases causes pneumonia and acute respiratory distress syndrome (ARDS) which can be fatal. Bronchial alveolar lavage fluid (BALF) and plasma from mild and severe cases of COVID-19 have been profiled using protein measurements and bulk and single cell RNA sequencing. Onset of pneumonia and ARDS can be rapid in COVID-19, suggesting a potential neuronal involvement in pathology and mortality. We hypothesized that SARS-CoV-2 infection drives changes in immune cell-derived factors that then interact with receptors expressed by the sensory neuronal innervation of the lung to further promote important aspects of disease severity, including ARDS. We sought to quantify how immune cells might interact with sensory innervation of the lung in COVID-19 using published data from patients, existing RNA sequencing datasets from human dorsal root ganglion neurons and other sources, and a genome-wide ligand-receptor pair database curated for pharmacological interactions relevant for neuro-immune interactions. Our findings reveal a landscape of ligand-receptor interactions in the lung caused by SARS-CoV-2 viral infection and point to potential interventions to reduce the burden of neurogenic inflammation in COVID-19 pulmonary disease. In particular, our work highlights opportunities for clinical trials with existing or under development rheumatoid arthritis and other (e.g. CCL2, CCR5 or EGFR inhibitors) drugs to treat high risk or severe COVID-19 cases.
Ray P.R., Wangzhou A., Ghneim N., Yousuf M.S., Paige C., Tavares-Ferreira D., Mwirigi J.M., Shiers S., Sankaranarayanan I., McFarland A.J., Neerukonda S.V., Davidson S., Dussor G., Burton M.D., Price T.J.
June 2020
JCI Insight
The cellular basis of protease-activated receptor 2-evoked mechanical and affective pain
Protease-activated receptor 2 (PAR2) has long been implicated in inflammatory and visceral pain, but the cellular basis of PAR2-evoked pain has not been delineated. Although PAR2-evoked pain has been attributed to sensory neuron expression, RNA-sequencing experiments show ambiguous F2rl1 mRNA detection. Moreover, many pharmacological tools for PAR2 are nonspecific, acting also on the Mas-related GPCR family (Mrg) that are highly enriched in sensory neurons. We sought to clarify the cellular basis of PAR2-evoked pain. We developed a PAR2-conditional knockout mouse and specifically deleted PAR2 in all sensory neurons using the PirtCre mouse line. Our behavioral findings show that PAR2 agonist-evoked mechanical hyperalgesia and facial grimacing, but not thermal hyperalgesia, are dependent on PAR2 expression in sensory neurons that project to the hind paw in male and female mice. F2rl1 mRNA is expressed in a discrete population (~4%) of mostly small-diameter sensory neurons that coexpress the Nppb and IL31ra genes. This cell population has been implicated in itch, but our work shows that PAR2 activation in these cells causes clear pain-related behaviors from the skin. Our findings show that a discrete population of DRG sensory neurons mediate PAR2-evoked pain.
Hassler S.N., Kume M., Mwirigi J.M., Ahmad A.+, Shiers S., Wangzhou A., Ray P.R., Belugin S.N., Naik D.K., Burton M.D., Vagner J., Boitano S., Akopian A.N., Dussor G., Price T.J.
June 2020
Pain
Migraine is one of the most disabling disorders worldwide but the underlying mechanisms are poorly understood. Stress is consistently reported as a common trigger of migraine attacks. Here, we show that repeated stress in mice causes migraine-like behaviors that are responsive to a migraine therapeutic. Adult female and male mice were exposed to 2 hours of restraint stress for 3 consecutive days, after which they demonstrated facial mechanical hypersensitivity and facial grimace responses that were resolved by 14 days after stress. Hypersensitivity or grimace was not observed in either control animals or those stressed for only 1 day. After return to baseline, the nitric oxide donor sodium nitroprusside (SNP; 0.1 mg/kg) elicited mechanical hypersensitivity in stressed but not in control animals, demonstrating the presence of hyperalgesic priming. This suggests the presence of a migraine-like state, because nitric oxide donors are reliable triggers of attacks in migraine patients but not controls. The stress paradigm also caused priming responses to dural pH 7.0 treatment. The presence of this primed state after stress is not permanent because it was no longer present at 35 days after stress. Finally, mice received either the calcitonin gene-related peptide monoclonal antibody ALD405 (10 mg/kg) 24 hours before SNP or a coinjection of sumatriptan (0.6 mg/kg). ALD405, but not sumatriptan, blocked the facial hypersensitivity due to SNP. This stress paradigm in mice and the subsequent primed state caused by stress allow further preclinical investigation of mechanisms contributing to migraine, particularly those caused by common triggers of attacks.
Avona A, Mason B, Lackovic J, Wajahat N, Motina M, Quigley L, Burgos-Vega C, Loomis C, Garcia-Martinez L, Akopian A, Price T, Dussor G.
June 2020
Neurobiology of Pain
Though sex differences in chronic pain have been consistently described in the literature, their underlying neural mechanisms are poorly understood. Previous work in humans has demonstrated that men and women differentially invoke distinct brain regions and circuits in coping with subjective pain unpleasantness. The goal of the present work was to elucidate the molecular mechanisms in the basolateral nucleus of the amygdala (BLA) that modulate hyperalgesic priming, a pain plasticity model, in males and females. We used plantar incision as the first, priming stimulus and prostaglandin E2 (PGE2) as the second stimulus. We sought to assess whether hyperalgesic priming can be prevented or reversed by pharmacologically manipulating molecular targets in the BLA of male or female mice. We found that administering ZIP, a cell-permeable inhibitor of aPKC, into the BLA attenuated aspects of hyperalgesic priming induced by plantar incision in males and females. However, incision only upregulated PKCζ/PKMζ immunoreactivity in the BLA of male mice, and deficits in hyperalgesic priming were seen only when we restricted our analysis to male Prkcz-/- mice. On the other hand, intra-BLA microinjections of pep2m, a peptide that interferes with the trafficking and function of GluA2-containing AMPA receptors, a downstream target of aPKC, reduced mechanical hypersensitivity after plantar incision and disrupted the development of hyperalgesic priming in both male and female mice. In addition, pep2m treatment reduced facial grimacing and restored aberrant behavioral responses in the sucrose splash test in male and female primed mice. Immunofluorescence results demonstrated upregulation of GluA2 expression in the BLA of male and female primed mice, consistent with pep2m findings. We conclude that, in a model of incision-induced hyperalgesic priming, PKCζ/PKMζ in the BLA is critical for the development of hyperalgesic priming in males, while GluA2 in the BLA is crucial for the expression of both reflexive and affective pain-related behaviors in both male and female mice in this model. Our findings add to a growing body of evidence of sex differences in molecular pain mechanisms in the brain.
June 2023
Garrity R, Arora N, Haque MA, Weis D, Trinh RT, Neerukonda SV, Kumari S, Ubogo EE,
Mahalingam R, Price TJ, Kavelaars A, Heijnen CJ, Shepherd AJ (2023) Fibroblast-derived
PI16 sustains inflammatory pain via regulation of CD206+ myeloid cells. Brain, Behavior and
Immunity. 112:220-234.
Lesnak JB, Mazhar K, Price TJ. (2023) Neuroimmune mechanisms underlying post-acute
sequelae of SARS-CoV-2 (PASC) pain, predictions from a ligand-receptor interactome.
Current Rheumatology Reports. 1-13.
May 2023
Miller Neilan RC, Reith C, Anandan IUG, Kraeter K, Allen H, BJ Kolber C*. (2023). Developing a 3-D
computational model of neurons in the central amygdala to understand pharmacological targets for
pain. Frontiers in Pain Research 4. doi: 10.3389/fpain.2023.1183553
Mitchel ME, Cook LC, Shiers S, Tavares-Ferreira D, Akopian AN, Dussor G, Price TJ (2023)
Characterization of fragile X mental retardation protein (FMRP) expression in human
nociceptors and their axonal projections to the spinal dorsal horn. Journal of Comparative
Neurology. 531(7):814-835
Rodriguez-Palma EJ, De la Luz-Cuellar YE, Islas-Espinoza AM, Felix-Leyva AE, Shiers S,
Garcia G, Torres-Lopez JE, Delgado-Lezama R, Murbartian J, Price TJ, Granados-Soto V.
(2022) Activation of 6-containg GABAA receptor induces antinociception under physiological
and pathological conditions. PAIN. 164(5):948-966.
April 2023
Mason BN, Hassler SN, Boitano S, Vagner J, DeFea KA, Price TJ, Dussor G (2023) PAR2
activation in the dura causes acute behavioral response and priming to glyceryl trinitrate in a
mouse migraine model. Journal of Headache and Pain. 24(1):42
De la Pena J, Chase R, Kunder N, Smith P, Tzu-Fang L, Stanowick A, Suresh P, Shukla T,
Butcher S, Price TJ, Campbell ZT (2023) Inhibition of nonsense-mediated decay produces nociceptive sensitization through activation of the integrated stress response. Journal of
Neuroscience 43(16):2921-2933.
Shiers S, Sahn JJ, Price TJ (2023) MNK1 and MNK2 expression in the human dorsal root and
trigeminal ganglion. Neuroscience. 515. 96-107
Sankaranarayanan I, Tavares-Ferreira D, He L, Kume M, Mwirigi JM, Madsen TM, Petersen
KA, Munro G, Price TJ. (2022) Meteorin alleviated paclitaxel-induced peripheral neuropathic
pain in mice. Journal of Pain. S1526-5900(22)-0441-2.
March 2023
Ehlers VL, Sadler KE, Stucky CL (2023). Peripheral TRPV4 hypersensitivity contributes to chronic sickle
cell disease pain. Pain 164(8): 1874-1886.
Alexander, S.N., Jeong, H.S., Szabo-Pardi, T.A., Burton, M.D. Sex-specific differences in alcohol-
induced pain sensitization. Neuropharmacology. 2023 Mar 1;225:109354. doi:
10.1016/j.neuropharm.2022.109354. Epub 2022 Nov 29
Dos Santos, N.L., Lenert, M.E., Castillo, Z.W., Mody, P.H., Thompson, L.T., Burton, M.D.
Postoperative pain drives differential behavioral and neuroimmune phenotypes across age and sex.
Neurobiol Aging. 2023 Mar;123:129-144. doi: 10.1016/j.neurobiolaging.2022.09.008. Epub 2022 Nov
23
Lackovic J, Jeevakumar V, Burton MD, Price TJ, Dussor G (2023) Peroxynitrite contributes to
behavioral responses, increased trigeminal excitability, and changes in mitochondrial function
in a preclinical model of migraine. Journal of Neuroscience. 43(9):1627-1642.
Walters ET, Crook, RJ, Neely GG, Price TJ, St John Smith E (2023) Persistent nociceptor
hyperactivity as a painful evolutionary adaptation. Trends in Neurosciences, 46(3):211-227
Schiff HV, Rivas CM, Pederson WP, Sandoval E, Gillman S, Prisco J, Kume M, Dussor G,
Vagner J, Ledford JG, Price TJ, DeFea KA, Boitano S. (2022) β-arrestin-biased proteinase-
16 activated receptor-2 antagonist C781 limits allergen-induced airway hyperresponsiveness and
inflammation. British Journal of Pharmacology. 180(5):667-680
Feb 2023
Hough A, Criswell C, Faruk A, Cavanaugh J, Kolber BJC, K TidgewellC (2023). Barbamide displays
affinity for membrane-bound receptors and impacts store-operated calcium entry in mouse sensory
neurons. Marine Drugs 21(2). doi: 10.3390/md21020110 *Equal contribution
Al-Karagholi MA, Kalatharan V, Ghanizada H, Gram C, Dussor G, Ashina M. (2023) Prolactin in
headache and migraine: a systemic review of clinical studies. Cephalalgia. 2023
Feb;43(2):3331024221136286. doi: 10.1177/03331024221136286
Kume M, Ahmad A, DeFea KA, Vagner J, Dussor G, Boitano S, Price TJ (2023) Protease-
Activated Receptor 2 (PAR2) expressed in sensory neurons contributes to signs of pain and
neuropathy in paclitaxel treated mice. Journal of Pain. S1526-5900(23)00441-8.
Sankaranarayanan I, Tavares-Ferreira D, Mwirigi JM, Mejia GL, Burton MD, Price TJ (2023)
Inducible co-stimulatory molecule (ICOS) alleviated paclitaxel-induced neuropathic pain via an
IL-10-mediated mechanism in female mice. Journal of Neuroinflammation. 20(1):32.
Ray PR, Shiers S, Caruso JP, Tavares-Ferreira D, Sankaranarayanan I, Uhelski ML, Li Y,
North RY, Tatsui C, Dussor G, Burton MD, Dougherty PM, Price TJ. (2023) RNA profiling of
human dorsal root ganglia reveals sex-difference in mechanisms promoting neuropathic pain.
Brain. 146(2) 749-766.
Jan 2023
Do TP, Hougaard A, Dussor G, Brennan KC, Amin FM. (2023) Migraine attacks are of peripheral origin:
the debate goes on. J Headache Pain. 2023 Jan 10;24(1):3. doi: 10.1186/s10194-022-01538-1
Upadhyayula, S+, Pemberton, E.J.+, Burton, M.D. Getting to the bottom of Cancer Treatment Pain.
Front. Young Minds. 11:783791. doi: 10.3389/frym.2022.783791
Dec 2022
Mason BN, Kallianpur R, Price TJ, Akopian AN, Dussor GO (2022) Prolactin signaling modulates
stress-induced behavioral responses in a preclinical mouse model of migraine. Headache. Dec 29. doi:
10.1111/head.14248.
Hegarty DM, Carrol JR, Nguyen D, Halls VS, Robbins DI, Price TJ, Dussor G, Aicher SA
(2022) Resveratrol increases tear production and ocular pain after corneal abrasion in male,
but not female, rats using a photorefractive keratectomy model. Experimental Eye Research.
225:109281.
Nov 2022
Kume M, Ahmad A, Shiers S, Burton MD, DeFea KA, Vagner J, Dussor G, Boitano S, Price TJ. (2022)
C781, a beta-arrestin biased antagonist at protease-activated receptor-2 (PAR2), displays in vivo efficacy
against protease-induced pain in mice. J Pain. 2022 Nov 20:S1526-5900(22)00454-0. doi:
10.1016/j.jpain.2022.11.006.
Castillo, Z.W.+ and Burton, M.D. Utilizing multiphoton imaging and integrative clearing to reveal sex
differences in neuroimmune interactions after nerve injury. Neural Regeneration Research. 2022
Papalampropoulou-Tsiridou M, Shiers S, Wang F, Godin AG, Price TJ, De Koninck Y (2022)
Distribution of acid-sensing ion channel subunits in human sensory neurons contrasts with that
in rodents. Brain Reports. 4(6):fcac256.
Oct 2022
Lackovic J, Price TJ, Dussor G (2022) MNK1/2 contributes to periorbital hypersensitivity and
hyperalgesic priming in preclinical migraine models. Brain. Oct 27. awac386. doi:
10.1093/brain/awac386
Sept 2022
Allen HNG, Chaudhry S, Hong VMG, Lewter LAPD, Sinha GP, Carrasquillo Y, Taylor BK, Kolber BJC.
(2023) A parabrachial-to-amygdala circuit that determines hemispheric lateralization of
somatosensory processing. Biological Psychiatry 93(4): 370-381. doi: 10.1016/j.biopsych.2022.09.010. Note: Accepted for publication Fall 2022
Mikesell AR, Isaeva O, Moehring F, Sadler KE, Menzel AD, Stucky CL (2022). Keratinocyte PIEZO1
modulates cutaneous mechanosensation. eLife11:e65987
Tierney, J.A.+, Uong, C.D.+, Lenert, M.E., Williams, M.+, Burton, M.D. High-fat Diet causes
mechanical allodynia in the absence of previous injury or diabetic pathology. Scientific Reports. 2022
Sep 1:12(1). Doi 10.1038/s41598-022-18281-x
Aug 2022
Garner, K.M. and Burton, M.D. The sex-specific role of sensory neurons LKB1 on metabolic stress-
induced mechanical hypersensitivity and mitochondrial respiration. American Journal of Physiology:
Regulatory, Integrative, & Comparative Physiology. 2022 Aug 1:323(2) doi:10.1152/ajpregu00279.2020
July 2022
Ray PR, Shiers S, Caruso JP, Tavares-Ferreira D, Sankaranarayanan I, Uhelski ML, Li Y, North RY,
Tatsui C, Dussor G, Burton MD, Dougherty PM, Price TJ. (2022) RNA profiling of human dorsal root
ganglia reveals sex-differences in mechanisms promoting neuropathic pain. Brain. 2022 Jul 22:awac266.
doi: 10.1093/brain/awac266.
June 2022
Schiff HV, Rivas CM, Pederson WP, Sandoval E, Gillman S, Prisco J, Kume M, Dussor G, Vagner J,
Ledford JG, Price TJ, DeFea KA, Boitano S. (2022) Beta-arrestin-biased proteinase-activated receptor-2
antagonist C781 limits allergen-induced airway hyperresponsiveness and inflammation. Br J Pharmacol.
2022 Jun 23. doi: 10.1111/bph.15903.
Lenert, M.E., Szabo-Pardi, T.A., Burton, M.D. Regulatory T-cells and IL-5 mediate pain outcomes in a
preclinical model of chronic muscle pain. Molecular Pain. 2022 Jun 17. Doi: 10.1177/17448069221
Letzen, J.E., Mathur, V.A., Janevic, M.R., Burton, M.D., Hood, A.M., Morais, C.A., Booker, S.Q.,
Campbell, C.M., Aroke, E.N., Campbell, L.C., Merriwether, E.N. Confronting Racism in All Forms of
Pain Research: Reframing Study Designs. Journal of Pain. 2022 Jun. doi: 10.1016/j.jpain.2022.01.010
April 2022
Vidal A, Jha S, Hassler S, Price TJ, Busso C (2022) Face detection and grimace scale
prediction of white furred mice. Machine Learning with Applications. 8: 100312
June 2020
Journal of Clinical Investigation Insight
The Cellular Basis of Protease-Activated Receptor 2-evoked Mechanical and Affective Pain
Protease-activated receptor 2 (PAR2) has long been implicated in inflammatory and visceral pain, but the cellular basis of PAR2-evoked pain has not been delineated. We sought to clarify the cellular basis of PAR2-evoked pain. We developed a PAR2-conditional knockout mouse and specifically deleted PAR2 in all sensory neurons using the PirtCre mouse line. Our behavioral findings show that PAR2 agonist-evoked mechanical hyperalgesia and facial grimacing, but not thermal hyperalgesia, are dependent on PAR2 expression in sensory neurons that project to the hind paw in male and female mice. F2rl1 mRNA is expressed in a discrete population (~4%) of mostly small-diameter sensory neurons that coexpress the Nppb and IL31ra genes.
Hassler SN, Kume M, Mwirigi K, Ahmad A, Shiers S, Wangzhou A, Ray P, Belugin SN, Naik DJ, Burton MD, Vagner J, Boitano S, Akopian AN, Dussor G, Price TJ
May 2020
Pain Management for Clinicians: A Guide to Assessment and Treatment
The Future of Pain Therapeutics
New chronic pain therapeutics are desperately needed, as many current treatments do not adequately treat pain in many patients. Ongoing preclinical research has found promising new techniques to better diagnose pain mechanisms and to treat pain. In this chapter we will focus on cutting edge technologies that show the most promise to provide relief for the millions of chronic pain patients seeking treatment. The chapter will cover the potential for emergence of new pharmaceuticals, implanted devices, genetic therapies, and behavioral modifications that may well be available in the coming years.
Paige C, Shiers S, Price TJ
April 2020
Journal of Neuroscience
Type I Interferons Act Directly on Nociceptors to Produce Pain Sensitization: Implications for Viral Infection-Induced Pain
One of the first signs of viral infection is body-wide aches and pain. Although this type of pain usually subsides, at the extreme, viral infections can induce painful neuropathies that can last for decades. Neither of these types of pain sensitization is well understood. We demonstrate that type I IFNRs are expressed in small/medium DRG neurons and that their activation produces neuronal hyper-excitability and mechanical pain in mice.
Barragan-Iglesias P, Franco-Enzastiga U, Jeevakumar V, Shiers S, Wangzhou A, Granados-Soto V, Campbell ZT, Dussor G, Price TJ
April 2020
Journal of Neuroscience Methods
Isolation, Culture, and Downstream Characterization of Primary Microglia and Astrocytes From Adult Rodent Brain and Spinal Cord
Here we show a novel, single protocol to isolate microglia and astrocytes from brain and spinal cord tissue, allowing for culturing and other downstream applications from the cells of animals of various ages, which will be useful for researchers investigating these two major glial cell types from the brain or spinal cord of the same rodent.
Agalave NM, Lane BT, Mody PH, Szabo-Pardi TA, Burton MD
March 2020
Angewandte Chemie International Edition
Near-Infrared Light Triggered-Release in Deep Brain Regions Using Ultra-photosensitive Nanovesicles
Remote and minimally-invasive modulation of biological systems with light has transformed modern biology and neuroscience. However, light absorption and scattering significantly prevents penetration to deep brain regions. Herein, we describe the use of gold-coated mechanoresponsive nanovesicles, which consist of liposomes made from the artificial phospholipid Rad-PC-Rad as a tool for the delivery of bioactive molecules into brain tissue. Near-infrared picosecond laser pulses activated the gold-coating on the surface of nanovesicles, creating nanomechanical stress and leading to near-complete vesicle cargo release in sub-seconds. Compared to natural phospholipid liposomes, the photo-release was possible at 40 times lower laser energy. This high photosensitivity enables photorelease of molecules down to a depth of 4 mm in mouse brain. This promising tool provides a versatile platform to optically release functional molecules to modulate brain circuits.
Xiong H., Li X., Neuhaus F., Perish J., Ploski J., Kroener S., Wang, H., Ogunyankin M.O., Shin J.E., Zasadzinski J.A., Slesinger P., Zumbuehl A. and Qin Z.
March 2020
Pain
Pharmacological Target-Focused Transcriptomic Analysis of Native Versus Cultured Human and Mouse Dorsal Root Ganglia
Dorsal root ganglion (DRG) neurons detect sensory inputs and are crucial for pain processing. They are often studied in vitro as dissociated cell cultures with the assumption that this reasonably represents in vivo conditions. However, to our knowledge, no study has directly compared genome-wide transcriptomes of DRG tissue in vivo versus in vitro, or between laboratories and culturing protocols. Comparing RNA sequencing-based transcriptomes of native to cultured (4 days in vitro) human or mouse DRG, we found that the overall expression levels of many ion channels and GPCRs specifically expressed in neurons are markedly lower although still expressed in culture.
Wangzhou A, McIlvried, Paige C, Barragan-Iglesias P, Shiers S, Ahmad A, Guzman CA, Dussor G, Ray PR, Gereau RW, Price TJ
March 2020
Cell
Mycobacterium Tuberculosis Sulfolipid-1 Activates Nociceptive Neurons and Induces Cough
Pulmonary tuberculosis, a disease caused by Mycobacterium tuberculosis (Mtb), manifests with a persistent cough as both a primary symptom and mechanism of transmission. Here, we show that a Mtb organic extract activates nociceptive neurons in vitro and identify the Mtb glycolipid sulfolipid-1 (SL-1) as the nociceptive molecule. Mtb organic extracts from mutants lacking SL-1 synthesis cannot activate neurons in vitro or induce cough in a guinea pig model. Finally, Mtb-infected guinea pigs cough in a manner dependent on SL-1 synthesis. Thus, we demonstrate a heretofore unknown molecular mechanism for cough induction by a virulent human pathogen via its production of a complex lipid.
Ruhl CR, Pasko BL, Khan HS, Kindt LM, Stamm CE, Franco LH, Hsia CC, Zhou M, Davis CR, Qin T, Gautron L, Burton MD, Naik DK, Dussor G, Price TJ, Shiloh MU
February 2020
Neuropsychopharmacology
Reversal of peripheral nerve injury-induced neuropathic pain and cognitive dysfunction via genetic and tomivosertib targeting of MNK.
Neuropathic pain caused by nerve injury presents with severe spontaneous pain and a variety of comorbidities, including deficits in higher executive functions. None of these clinical problems are adequately treated with current analgesics. Our results illustrate new testing paradigms for determining preclinical neuropathic pain efficacy and point to the MNK inhibitor tomivosertib (eFT508) as an important drug candidate for neuropathic pain treatment.
Shiers S, Mwirigi J, Pradhan G, Kume M, Black B, Barragan-Iglesias P, Moy JK, Dussor G, Pancrazio JJ, Kroener S, Price TJ
2020
Dynamics of Pain
Chapter 4: The Basics – Translation Regulation and Pain
Pain is a condition that affects us all at one point or another. It is an adaptive response to avoid further injury and, following an injury, the pain in a body region is present to promote behaviors that guard the area to allow for the healing process to repair the injury. For that reason, the same cells that fix the problems are the ones that result in inflammation and increased sensitivity. Unfortunately, for some individuals, pain from an injury can last much longer than the normal healing time or arise for no clear reason whatsoever. For those chronic pain sufferers, an understanding of the mechanisms of chronic pain can aid in development of treatments to alleviate this burden.
Yousuf MS, Price TJ
2020
Dynamics of Pain
Chapter 16: Alternative and complementary modulation
Pain is a condition that affects us all at one point or another. It is an adaptive response to avoid further injury and, following an injury, the pain in a body region is present to promote behaviors that guard the area to allow for the healing process to repair the injury. For that reason, the same cells that fix the problems are the ones that result in inflammation and increased sensitivity. Unfortunately, for some individuals, pain from an injury can last much longer than the normal healing time or arise for no clear reason whatsoever. For those chronic pain sufferers, an understanding of the mechanisms of chronic pain can aid in development of treatments to alleviate this burden.
BJ Kolber & L Lewter
2019
November 2019
ACS Nano
Transient Photoinactivation of Cell Membrane Protein Activity Without Genetic Modification by Molecular Hyperthermia
Precise manipulation of protein activity in living systems has broad applications in biomedical sciences. However, it is challenging to use light to manipulate protein activity in living systems without genetic modification. Here, we report a technique to optically switch off protein activity in living cells with high spatiotemporal resolution, referred to as molecular hyperthermia (MH)
Kang P, Li X, Liu Y, Shiers S, Xiong H, Giannotta M, Dejana E, Price TJ, Randrianalisoa J, Neilsen SO, Qin Z
November 2019
Wiley Interdisciplinary Review RNA
RNA Control in Pain: Blame It on the Messenger
mRNA function is meticulously controlled. We provide an overview of the integral role that posttranscriptional controls play in the perception of painful stimuli by sensory neurons. These specialized cells, termed nociceptors, precisely regulate mRNA polarity, translation, and stability. A growing body of evidence has revealed that targeted disruption of mRNAs and RNA-binding proteins robustly diminishes pain-associated behaviors. We propose that the use of multiple independent regulatory paradigms facilitates robust temporal and spatial precision of protein expression in response to a range of pain-promoting stimuli.
De la Peña JBI, Song JJ, Campbell, ZT
October 2019
Journal of Dual Diagnosis
Cannabinoid Receptor Type 1 and Its Role as an Analgesic: An Opioid Alternative?
Pain is the most prominent reason why Americans seek medical attention and extensive literature has identified the importance of the endocannabinoid pathway in controlling pain. Recent physiological, pharmacological, and anatomical studies provide evidence that one of the main roles of the endocannabinoid system is the regulation of gamma-aminobutyric acid (GABA) and/or glutamate release. This article will review this evidence in the context of its implications for pain. We first provide a brief overview of CB1R’s role in the regulation of nociception, followed by a review of the evidence that the peripheral endocannabinoid system modulates nociception.
Milligan AL, Szabo-Pardi TA, Burton MD
October 2019
iScience
Prolactin Regulates Pain Responses via a Female-Selective Nociceptor-Specific Mechanism
Many clinical and preclinical studies report an increased prevalence and severity of chronic pain among females. Here, we identify a sex-hormone-controlled target and mechanism that regulates dimorphic pain responses.
Patil M, Belugin S, Mecklenburg J, Wangzhou A, Paige C, Barba-Escobedo PA, Boyd JT, Goffin V, Grattan D, Boehm U, Dussor G, Price TJ, Akopian AN
October 2019
Current Opinion in Physiology
New Discoveries in Migraine Mechanisms and Therapeutic Targets
Migraine is among the most common and most disabling disorders worldwide, yet its underlying pathophysiology is among the most poorly understood. This review will cover new findings within the last several years that add to the understanding of migraine pathophysiology, including those related to the vasculature, calcitonin gene-related peptide (CGRP), and mechanisms within the cortex and meninges that may contribute to attacks. Discussion will also cover recent findings on novel therapeutic targets, several of which continue to show promise in new preclinical studies, including acid-sensing ion channels (ASICs) and the delta-opioid receptor (DOR).
Dussor, G
September 2019
Philosophical Transactions of the Royal Society of London B.
MNK-eIF4E signaling is a highly conserved mechanism for sensory neuron axonal plasticity: evidence from Aplysia californica.
We propose that MNK-eIF4E signalling is a core, evolutionarily conserved, signalling module that controls nociceptor plasticity. This finding has important implications for the therapeutic potential of this target, and it provides interesting clues about the evolutionary origins of mechanisms important for pain-related plasticity.
Mihail SM, Wangzhou A, Kunjilwar KK, Moy JK, Dussor G, Walters ET, Price TJ
September 2019
Neurobiology of Pain
Alleviation of paclitaxel-induced mechanical hypersensitivity and hyperalgesic priming with AMPK activators in male and female mice
AMP-activated protein kinase (AMPK) is an energy-sensing kinase that has emerged as a novel therapeutic target for pain due to its ability to inhibit mechanistic target of rapamycin (mTOR) and mitogen activated protein kinase (MAPK) signaling, two signaling pathways that are linked to pain promotion after injury as well as the development of hyperalgesic priming. MAPK and mTOR signaling are also implicated in chemotherapy induced peripheral neuropathy (CIPN). We conducted a series of experiments to gain further insight into how AMPK activators might best be used to treat pain in both sexes in the setting of CIPN from paclitaxel. We also assessed whether hyperalgesic priming emerges from paclitaxel treatment and if this can be prevented by AMPK targeting. AMPK can be pharmacologically activated indirectly through regulation of upstream kinases like liver kinase B1 (LKB1) or directly using positive allosteric modulators.
Inyang KE, McDougal TA, Ramirez ED, Williams M, Laumet G, Kavelaars A, Heijnen CJ, Burton MD, Dussor G, Price TJ
August 2019
Experimental Gereontology
Aging Sensitizes Male Mice to Cognitive Dysfunction Induced by Central HIV-1 gp120
Although highly active antiretroviral therapy has led to improved prognosis and alleviation of some HIV-related disease complications, it has not provided complete protection against HIV-associated dementia. As the population of persons living with HIV grows older and aged persons represent a significant number of new infections, it is important to understand how HIV may affect the aged brain. In the current study, both adult and aged mice were treated with HIV gp120 and trained in a reference memory version of the water maze. Analysis of probe data revealed that aged animals treated with gp120 demonstrated profound decrements in water maze performance compared to gp120 treated young animals and saline treated aged or young animals.
Sparkman NL, Buchanan J, Dos Santos NL, Johnson RW, Burton MD