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Saika F, Fukazawa Y, Kishioka S, Kiguchi N. Characterization of spinal microglial activation in a mouse model of imiquimod-induced psoriasis. J Pharmacol Sci 2023; 153:183-187. [PMID: 37973215 DOI: 10.1016/j.jphs.2023.09.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Revised: 09/01/2023] [Accepted: 09/15/2023] [Indexed: 11/19/2023] Open
Abstract
Although microglia are associated with chronic pain, the role of spinal microglia in the regulation of itch remains unclear. In this study, we characterized spinal microglial activation in a mouse model of imiquimod (IMQ)-induced psoriasis. Hypertrophic (activated) microglia were observed throughout the spinal cord after the topical application of IMQ. Furthermore, the mRNA expression of microglial markers and inflammatory mediators was upregulated. Ablation of itch-related sensory neurons using resiniferatoxin decreased itch-related scratching behavior and the number of hypertrophic microglia in the spinal dorsal horn. Conclusively, sensory neuron input may partially contribute to spinal microglial activation after IMQ application.
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Affiliation(s)
- Fumihiro Saika
- Faculty of Wakayama Health Care Sciences, Takarazuka University of Medical and Health Care, Wakayama 640-8392, Japan; Department of Physiological Sciences, School of Pharmaceutical Sciences, Wakayama Medical University, Wakayama 640-8156, Japan
| | - Yohji Fukazawa
- Department of Anatomy, Kansai University of Health Sciences, Osaka 590-0482, Japan
| | - Shiroh Kishioka
- Faculty of Wakayama Health Care Sciences, Takarazuka University of Medical and Health Care, Wakayama 640-8392, Japan
| | - Norikazu Kiguchi
- Department of Physiological Sciences, School of Pharmaceutical Sciences, Wakayama Medical University, Wakayama 640-8156, Japan.
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2
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Nelson TS, Allen HN, Basu P, Prasoon P, Nguyen E, Arokiaraj CM, Santos DF, Seal RP, Ross SE, Todd AJ, Taylor BK. Alleviation of neuropathic pain with neuropeptide Y requires spinal Npy1r interneurons that coexpress Grp. JCI Insight 2023; 8:e169554. [PMID: 37824208 PMCID: PMC10721324 DOI: 10.1172/jci.insight.169554] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Accepted: 10/04/2023] [Indexed: 10/14/2023] Open
Abstract
Neuropeptide Y targets the Y1 receptor (Y1) in the spinal dorsal horn (DH) to produce endogenous and exogenous analgesia. DH interneurons that express Y1 (Y1-INs; encoded by Npy1r) are necessary and sufficient for neuropathic hypersensitivity after peripheral nerve injury. However, as Y1-INs are heterogenous in composition in terms of morphology, neurophysiological characteristics, and gene expression, we hypothesized that a more precisely defined subpopulation mediates neuropathic hypersensitivity. Using fluorescence in situ hybridization, we found that Y1-INs segregate into 3 largely nonoverlapping subpopulations defined by the coexpression of Npy1r with gastrin-releasing peptide (Grp/Npy1r), neuropeptide FF (Npff/Npy1r), and cholecystokinin (Cck/Npy1r) in the superficial DH of mice, nonhuman primates, and humans. Next, we analyzed the functional significance of Grp/Npy1r, Npff/Npy1r, and Cck/Npy1r INs to neuropathic pain using a mouse model of peripheral nerve injury. We found that chemogenetic inhibition of Npff/Npy1r-INs did not change the behavioral signs of neuropathic pain. Further, inhibition of Y1-INs with an intrathecal Y1 agonist, [Leu31, Pro34]-NPY, reduced neuropathic hypersensitivity in mice with conditional deletion of Npy1r from CCK-INs and NPFF-INs but not from GRP-INs. We conclude that Grp/Npy1r-INs are conserved in higher order mammalian species and represent a promising and precise pharmacotherapeutic target for the treatment of neuropathic pain.
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Affiliation(s)
- Tyler S. Nelson
- Department of Anesthesiology and Perioperative Medicine
- Pittsburgh Project to end Opioid Misuse
- Center for Neuroscience
| | - Heather N. Allen
- Department of Anesthesiology and Perioperative Medicine
- Pittsburgh Project to end Opioid Misuse
- Pittsburgh Center for Pain Research, and
| | - Paramita Basu
- Department of Anesthesiology and Perioperative Medicine
- Pittsburgh Project to end Opioid Misuse
- Pittsburgh Center for Pain Research, and
| | - Pranav Prasoon
- Department of Anesthesiology and Perioperative Medicine
- Pittsburgh Project to end Opioid Misuse
- Pittsburgh Center for Pain Research, and
| | - Eileen Nguyen
- Center for Neuroscience
- Pittsburgh Center for Pain Research, and
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Cynthia M. Arokiaraj
- Center for Neuroscience
- Pittsburgh Center for Pain Research, and
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Diogo F.S. Santos
- Department of Anesthesiology and Perioperative Medicine
- Pittsburgh Project to end Opioid Misuse
- Pittsburgh Center for Pain Research, and
| | - Rebecca P. Seal
- Center for Neuroscience
- Pittsburgh Center for Pain Research, and
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Sarah E. Ross
- Center for Neuroscience
- Pittsburgh Center for Pain Research, and
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Andrew J. Todd
- Spinal Cord Group, School of Psychology and Neuroscience, University of Glasgow, Glasgow, United Kingdom
| | - Bradley K. Taylor
- Department of Anesthesiology and Perioperative Medicine
- Pittsburgh Project to end Opioid Misuse
- Center for Neuroscience
- Pittsburgh Center for Pain Research, and
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
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3
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Nguyen E, Grajales-Reyes JG, Gereau RW, Ross SE. Cell type-specific dissection of sensory pathways involved in descending modulation. Trends Neurosci 2023; 46:539-550. [PMID: 37164868 PMCID: PMC10836406 DOI: 10.1016/j.tins.2023.04.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 03/22/2023] [Accepted: 04/07/2023] [Indexed: 05/12/2023]
Abstract
Decades of research have suggested that stimulation of supraspinal structures, such as the periaqueductal gray (PAG) and rostral ventromedial medulla (RVM), inhibits nocifensive responses to noxious stimulation through a process known as descending modulation. Electrical stimulation and pharmacologic manipulations of the PAG and RVM identified transmitters and neuronal firing patterns that represented distinct cell types. Advances in mouse genetics, in vivo imaging, and circuit tracing methods, in addition to chemogenetic and optogenetic approaches, allowed the characterization of the cells and circuits involved in descending modulation in further detail. Recent work has revealed the importance of PAG and RVM neuronal cell types in the descending modulation of pruriceptive as well as nociceptive behaviors, underscoring their roles in coordinating complex behavioral responses to sensory input. This review summarizes how new technical advances that enable cell type-specific manipulation and recording of neuronal activity have supported, as well as expanded, long-standing views on descending modulation.
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Affiliation(s)
- Eileen Nguyen
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Jose G Grajales-Reyes
- Washington University Pain Center and Department of Anesthesiology, Washington University School of Medicine in St Louis, St Louis, MO 63110, USA
| | - Robert W Gereau
- Washington University Pain Center and Department of Anesthesiology, Washington University School of Medicine in St Louis, St Louis, MO 63110, USA
| | - Sarah E Ross
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA.
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4
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Ghazisaeidi S, Muley MM, Salter MW. Neuropathic Pain: Mechanisms, Sex Differences, and Potential Therapies for a Global Problem. Annu Rev Pharmacol Toxicol 2023; 63:565-583. [PMID: 36662582 DOI: 10.1146/annurev-pharmtox-051421-112259] [Citation(s) in RCA: 33] [Impact Index Per Article: 33.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The study of chronic pain continues to generate ever-increasing numbers of publications, but safe and efficacious treatments for chronic pain remain elusive. Recognition of sex-specific mechanisms underlying chronic pain has resulted in a surge of studies that include both sexes. A predominant focus has been on identifying sex differences, yet many newly identified cellular mechanisms and alterations in gene expression are conserved between the sexes. Here we review sex differences and similarities in cellular and molecular signals that drive the generation and resolution of neuropathic pain. The mix of differences and similarities reflects degeneracy in peripheral and central signaling processes by which neurons, immune cells, and glia codependently drive pain hypersensitivity. Recent findings identifying critical signaling nodes foreshadow the development of rationally designed, broadly applicable analgesic strategies. However, the paucity of effective, safe pain treatments compels targeted therapies as well to increase therapeutic options that help reduce the global burden of suffering.
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Affiliation(s)
- Shahrzad Ghazisaeidi
- Program in Neurosciences & Mental Health, The Hospital for Sick Children, Toronto, Ontario, Canada;
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
- University of Toronto Centre for the Study of Pain, Toronto, Ontario, Canada
| | - Milind M Muley
- Program in Neurosciences & Mental Health, The Hospital for Sick Children, Toronto, Ontario, Canada;
- University of Toronto Centre for the Study of Pain, Toronto, Ontario, Canada
| | - Michael W Salter
- Program in Neurosciences & Mental Health, The Hospital for Sick Children, Toronto, Ontario, Canada;
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
- University of Toronto Centre for the Study of Pain, Toronto, Ontario, Canada
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5
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Nelson TS, Sinha GP, Santos DFS, Jukkola P, Prasoon P, Winter MK, McCarson KE, Smith BN, Taylor BK. Spinal neuropeptide Y Y1 receptor-expressing neurons are a pharmacotherapeutic target for the alleviation of neuropathic pain. Proc Natl Acad Sci U S A 2022; 119:e2204515119. [PMID: 36343228 PMCID: PMC9674229 DOI: 10.1073/pnas.2204515119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Accepted: 09/25/2022] [Indexed: 11/09/2022] Open
Abstract
Peripheral nerve injury sensitizes a complex network of spinal cord dorsal horn (DH) neurons to produce allodynia and neuropathic pain. The identification of a druggable target within this network has remained elusive, but a promising candidate is the neuropeptide Y (NPY) Y1 receptor-expressing interneuron (Y1-IN) population. We report that spared nerve injury (SNI) enhanced the excitability of Y1-INs and elicited allodynia (mechanical and cold hypersensitivity) and affective pain. Similarly, chemogenetic or optogenetic activation of Y1-INs in uninjured mice elicited behavioral signs of spontaneous, allodynic, and affective pain. SNI-induced allodynia was reduced by chemogenetic inhibition of Y1-INs, or intrathecal administration of a Y1-selective agonist. Conditional deletion of Npy1r in DH neurons, but not peripheral afferent neurons prevented the anti-hyperalgesic effects of the intrathecal Y1 agonist. We conclude that spinal Y1-INs are necessary and sufficient for the behavioral symptoms of neuropathic pain and represent a promising target for future pharmacotherapeutic development of Y1 agonists.
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Affiliation(s)
- Tyler S. Nelson
- Department of Anesthesiology and Perioperative Medicine, Center for Neuroscience, Pittsburgh Center for Pain Research, Pittsburgh Project to End Opioid Misuse, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
- Center for the Neural Basis of Cognition, University of Pittsburgh, Pittsburgh, PA 15261
| | - Ghanshyam P. Sinha
- Department of Anesthesiology and Perioperative Medicine, Center for Neuroscience, Pittsburgh Center for Pain Research, Pittsburgh Project to End Opioid Misuse, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
| | - Diogo F. S. Santos
- Department of Anesthesiology and Perioperative Medicine, Center for Neuroscience, Pittsburgh Center for Pain Research, Pittsburgh Project to End Opioid Misuse, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
| | - Peter Jukkola
- Department of Anesthesiology and Perioperative Medicine, Center for Neuroscience, Pittsburgh Center for Pain Research, Pittsburgh Project to End Opioid Misuse, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
| | - Pranav Prasoon
- Department of Anesthesiology and Perioperative Medicine, Center for Neuroscience, Pittsburgh Center for Pain Research, Pittsburgh Project to End Opioid Misuse, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
| | - Michelle K. Winter
- Kansas Intellectual and Developmental Disabilities Research Center; Department of Pharmacology, Toxicology, and Therapeutics, University of Kansas Medical Center, Kansas City, KS 66160
| | - Ken E. McCarson
- Kansas Intellectual and Developmental Disabilities Research Center; Department of Pharmacology, Toxicology, and Therapeutics, University of Kansas Medical Center, Kansas City, KS 66160
| | - Bret N. Smith
- Department of Neuroscience, University of Kentucky, Lexington, KY 40536
| | - Bradley K. Taylor
- Department of Anesthesiology and Perioperative Medicine, Center for Neuroscience, Pittsburgh Center for Pain Research, Pittsburgh Project to End Opioid Misuse, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
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Kiguchi N, Ding H, Park SH, Mabry KM, Kishioka S, Shiozawa Y, Alfonso Romero-Sandoval E, Peters CM, Ko MC. Functional roles of neuromedin B and gastrin-releasing peptide in regulating itch and pain in the spinal cord of non-human primates. Biochem Pharmacol 2022; 198:114972. [PMID: 35189108 PMCID: PMC10980179 DOI: 10.1016/j.bcp.2022.114972] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Revised: 02/15/2022] [Accepted: 02/15/2022] [Indexed: 11/15/2022]
Abstract
Despite accumulating evidence in rodents, the functional role of neuromedin B (NMB) in regulating somatosensory systems in primate spinal cord is unknown. We aimed to compare the expression patterns of NMB and its receptor (NMBR) and the behavioral effects of intrathecal (i.t.) NMB with gastrin-releasing peptide (GRP) on itch or pain in non-human primates (NHPs). We used six adult rhesus monkeys. The mRNA or protein expressions of NMB, GRP, and their receptors were evaluated by quantitative reverse transcription polymerase chain reaction, immunohistochemistry, or in situ hybridization. We determined the behavioral effects of NMB or GRP via acute thermal nociception, capsaicin-induced thermal allodynia, and itch scratching response assays. NMB expression levels were greater than those of GRP in the dorsal root ganglia and spinal dorsal horn. Conversely, NMBR expression was significantly lower than GRP receptor (GRPR). I.t. NMB elicited only mild scratching responses, whereas GRP caused robust scratching responses. GRP- and NMB-elicited scratching responses were attenuated by GRPR (RC-3095) and NMBR (PD168368) antagonists, respectively. Moreover, i.t. NMB and GRP did not induce thermal hypersensitivity and GRPR and NMBR antagonists did not affect peripherally elicited thermal allodynia. Consistently, NMBR expression was low in both itch- and pain-responsive neurons in the spinal dorsal horn. Spinal NMB-NMBR system plays a minimal functional role in the neurotransmission of itch and pain in primates. Unlike the functional significance of the GRP-GRPR system in itch, drugs targeting the spinal NMB-NMBR system may not effectively alleviate non-NMBR-mediated itch.
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Affiliation(s)
- Norikazu Kiguchi
- Department of Physiological Sciences, School of Pharmaceutical Sciences, Wakayama Medical University, Wakayama City, Wakayama 640-8156, Japan.
| | - Huiping Ding
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem, NC 27157, USA
| | - Sun H Park
- Department of Cancer Biology and Wake Forest Baptist Comprehensive Cancer Center, Wake Forest School of Medicine, Winston-Salem, NC 27157, USA
| | - Kelsey M Mabry
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem, NC 27157, USA
| | - Shiroh Kishioka
- Faculty of Wakayama Health Care Sciences, Takarazuka University of Medical and Health Care, Wakayama City, Wakayama 640-8392, Japan
| | - Yusuke Shiozawa
- Department of Cancer Biology and Wake Forest Baptist Comprehensive Cancer Center, Wake Forest School of Medicine, Winston-Salem, NC 27157, USA
| | | | - Christopher M Peters
- Department of Anesthesiology, Wake Forest School of Medicine, Winston-Salem, NC 27157, USA
| | - Mei-Chuan Ko
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem, NC 27157, USA.
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