1
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Tummino TA, Iliopoulos-Tsoutsouvas C, Braz JM, O'Brien ES, Stein RM, Craik V, Tran NK, Ganapathy S, Liu F, Shiimura Y, Tong F, Ho TC, Radchenko DS, Moroz YS, Rosado SR, Bhardwaj K, Benitez J, Liu Y, Kandasamy H, Normand C, Semache M, Sabbagh L, Glenn I, Irwin JJ, Kumar KK, Makriyannis A, Basbaum AI, Shoichet BK. Large library docking for cannabinoid-1 receptor agonists with reduced side effects. bioRxiv 2024:2023.02.27.530254. [PMID: 38328157 PMCID: PMC10849508 DOI: 10.1101/2023.02.27.530254] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2024]
Abstract
Large library docking can reveal unexpected chemotypes that complement the structures of biological targets. Seeking new agonists for the cannabinoid-1 receptor (CB1R), we docked 74 million tangible molecules, prioritizing 46 high ranking ones for de novo synthesis and testing. Nine were active by radioligand competition, a 20% hit-rate. Structure-based optimization of one of the most potent of these (Ki = 0.7 uM) led to '4042, a 1.9 nM ligand and a full CB1R agonist. A cryo-EM structure of the purified enantiomer of '4042 ('1350) in complex with CB1R-Gi1 confirmed its docked pose. The new agonist was strongly analgesic, with generally a 5-10-fold therapeutic window over sedation and catalepsy and no observable conditioned place preference. These findings suggest that new cannabinoid chemotypes may disentangle characteristic cannabinoid side-effects from their analgesia, supporting the further development of cannabinoids as pain therapeutics.
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2
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Braz JM, Hamel K, Craik V, Rodriguez-Rosado S, Bhardwaj K, Jewell M, Bieri G, Villeda SA, Basbaum AI. Pain and Itch Processing in Aged Mice. J Pain 2024; 25:53-63. [PMID: 37482234 DOI: 10.1016/j.jpain.2023.07.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Revised: 06/30/2023] [Accepted: 07/18/2023] [Indexed: 07/25/2023]
Abstract
Most reports agree that aging negatively impacts pain processing and that the prevalence of chronic pain increases significantly with age. To improve current therapies, it is critical that aged animals be included in preclinical studies. Here we compared sensitivities to pain and itch-provoking stimuli in naïve and injured young and aged mice. Surprisingly, we found that in the absence of injury, aged male and female mice are significantly less responsive to mechanical stimuli and, in females, also to noxious thermal (heat) stimuli. In both older male and female mice, compared to younger (6-month-old mice), we also recorded reduced pruritogen-evoked scratching. On the other hand, after nerve injury, aged mice nevertheless developed significant mechanical hypersensitivity. Interestingly, however, and in contrast to young mice, aged mice developed both ipsilateral and contralateral postinjury mechanical allodynia. In a parallel immunohistochemical analysis of microglial and astrocyte markers, we found that the ipsilateral to the contralateral ratio of nerve injury-induced expression decreased with age. That observation is consistent with our finding of contralateral hypersensitivity after nerve injury in the aged but not the young mice. We conclude that aging has opposite effects on baseline versus postinjury pain and itch processing. PERSPECTIVE: Aged male and female mice (22-24 months) are less sensitive to mechanical, thermal (heat), and itch-provoking stimuli than are younger mice (6 months).
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Affiliation(s)
- João M Braz
- Department of Anatomy, University of California, San Francisco, San Francisco, California
| | - Katherine Hamel
- Department of Anatomy, University of California, San Francisco, San Francisco, California
| | - Veronica Craik
- Department of Anatomy, University of California, San Francisco, San Francisco, California
| | - Sian Rodriguez-Rosado
- Department of Anatomy, University of California, San Francisco, San Francisco, California
| | - Karnika Bhardwaj
- Department of Anatomy, University of California, San Francisco, San Francisco, California
| | - Madison Jewell
- Department of Anatomy, University of California, San Francisco, San Francisco, California
| | - Gregor Bieri
- Department of Anatomy, University of California, San Francisco, San Francisco, California
| | - Saul A Villeda
- Department of Anatomy, University of California, San Francisco, San Francisco, California
| | - Allan I Basbaum
- Department of Anatomy, University of California, San Francisco, San Francisco, California
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3
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Gahbauer S, DeLeon C, Braz JM, Craik V, Kang HJ, Wan X, Huang XP, Billesbølle CB, Liu Y, Che T, Deshpande I, Jewell M, Fink EA, Kondratov IS, Moroz YS, Irwin JJ, Basbaum AI, Roth BL, Shoichet BK. Docking for EP4R antagonists active against inflammatory pain. Nat Commun 2023; 14:8067. [PMID: 38057319 PMCID: PMC10700596 DOI: 10.1038/s41467-023-43506-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Accepted: 11/12/2023] [Indexed: 12/08/2023] Open
Abstract
The lipid prostaglandin E2 (PGE2) mediates inflammatory pain by activating G protein-coupled receptors, including the prostaglandin E2 receptor 4 (EP4R). Nonsteroidal anti-inflammatory drugs (NSAIDs) reduce nociception by inhibiting prostaglandin synthesis, however, the disruption of upstream prostanoid biosynthesis can lead to pleiotropic effects including gastrointestinal bleeding and cardiac complications. In contrast, by acting downstream, EP4R antagonists may act specifically as anti-inflammatory agents and, to date, no selective EP4R antagonists have been approved for human use. In this work, seeking to diversify EP4R antagonist scaffolds, we computationally dock over 400 million compounds against an EP4R crystal structure and experimentally validate 71 highly ranked, de novo synthesized molecules. Further, we show how structure-based optimization of initial docking hits identifies a potent and selective antagonist with 16 nanomolar potency. Finally, we demonstrate favorable pharmacokinetics for the discovered compound as well as anti-allodynic and anti-inflammatory activity in several preclinical pain models in mice.
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Affiliation(s)
- Stefan Gahbauer
- Department of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, CA, 94158, USA
| | - Chelsea DeLeon
- Department of Pharmacology, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC, 27514, USA
| | - Joao M Braz
- Department of Anatomy, University of California San Francisco, San Francisco, CA, 94158, USA
| | - Veronica Craik
- Department of Anatomy, University of California San Francisco, San Francisco, CA, 94158, USA
| | - Hye Jin Kang
- Department of Pharmacology, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC, 27514, USA
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul, South Korea
| | - Xiaobo Wan
- Department of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, CA, 94158, USA
| | - Xi-Ping Huang
- Department of Pharmacology, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC, 27514, USA
| | - Christian B Billesbølle
- Department of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, CA, 94158, USA
| | - Yongfeng Liu
- Department of Pharmacology, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC, 27514, USA
| | - Tao Che
- Department of Pharmacology, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC, 27514, USA
- Center of Clinical Pharmacology, Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Ishan Deshpande
- Department of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, CA, 94158, USA
| | - Madison Jewell
- Department of Anatomy, University of California San Francisco, San Francisco, CA, 94158, USA
| | - Elissa A Fink
- Department of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, CA, 94158, USA
| | - Ivan S Kondratov
- Enamine Ltd., Kyiv, Ukraine
- V.P. Kukhar Institute of Bioorganic Chemistry and Petrochemistry, National Academy of Sciences of Ukraine, Kyiv, Ukraine
| | - Yurii S Moroz
- Chemspace LLC, Kyiv, Ukraine
- National Taras Shevchenko University of Kyiv, Kyiv, Ukraine
| | - John J Irwin
- Department of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, CA, 94158, USA
| | - Allan I Basbaum
- Department of Anatomy, University of California San Francisco, San Francisco, CA, 94158, USA.
| | - Bryan L Roth
- Department of Pharmacology, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC, 27514, USA.
- National Institute of Mental Health Psychoactive Drug Screening Program, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC, 27514, USA.
- Division of Chemical Biology and Medicinal Chemistry, University of North Carolina at Chapel Hill Eshelman School of Pharmacy, Chapel Hill, NC, 27514, USA.
| | - Brian K Shoichet
- Department of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, CA, 94158, USA.
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4
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Basbaum AI, Jensen TS, Keefe FJ. Fifty years of pain research and clinical advances: highlights and key trends. Pain 2023; 164:S11-S15. [PMID: 37831954 PMCID: PMC10787538 DOI: 10.1097/j.pain.0000000000003058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Accepted: 07/31/2023] [Indexed: 10/15/2023]
Abstract
ABSTRACT This article highlights advances in basic science preclinical pain research, clinical research, and psychological research occurring over the 50 years since the International Association for the Study of Pain was founded. It presents important findings and key trends in these 3 areas of pain science: basic science preclinical research, clinical research, and psychological research.
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Affiliation(s)
- Allan I. Basbaum
- Department of Anatomy, University California San Francisco, San Francisco, CA USA 94158
| | - Troels. S Jensen
- Danish Pain Research Center, Department of Clinical Medicine, Aarhus University Hosital, DK, 8200 Aarhus N, Denmark
| | - Francis J. Keefe
- Duke Pain Prevention and Treatment Research Program, Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, NC, USA 27705
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5
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Davis KD, Basbaum AI, Bushnell MC, Yarnitsky D, Fields HL. International Association for the Study of Pain publications over the 50-year span. Pain 2023; 164:S27-S30. [PMID: 37831957 DOI: 10.1097/j.pain.0000000000003059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Accepted: 07/10/2023] [Indexed: 10/15/2023]
Abstract
ABSTRACT The International Association for the Study of Pain (IASP) has a 50-year history of publishing educational and research materials, ranging from traditional print format books, journals, and other informational formats to online and electronic formats. Here we provide a historical overview of IASP publications and reflections from the perspective of 5 former or current Editors-in-Chief.
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Affiliation(s)
- Karen D Davis
- Division of Brain, Imaging, and Behaviour, Krembil Brain Institute, University Health Network, Toronto, ON, Canada
- Department of Surgery and Institute of Medical Science, University of Toronto, Toronto, ON, Canada
| | - Allan I Basbaum
- Department of Anatomy, University California San Francisco, San Francisco, CA, United States
| | | | - David Yarnitsky
- Department of Neurology, Rambam Health Care Campus, and Laboratory of Clinical Neurophysiology, Technion Faculty of Medicine, Haifa, Israel
| | - Howard L Fields
- Departments of Neurology and Physiology, University of California San Francisco, San Francisco, CA, United States
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6
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Fassett MS, Braz JM, Castellanos CA, Salvatierra JJ, Sadeghi M, Yu X, Schroeder AW, Caston J, Munoz-Sandoval P, Roy S, Lazarevsky S, Mar DJ, Zhou CJ, Shin JS, Basbaum AI, Ansel KM. IL-31-dependent neurogenic inflammation restrains cutaneous type 2 immune response in allergic dermatitis. Sci Immunol 2023; 8:eabi6887. [PMID: 37831760 PMCID: PMC10890830 DOI: 10.1126/sciimmunol.abi6887] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Accepted: 08/18/2023] [Indexed: 10/15/2023]
Abstract
Despite robust literature associating IL-31 with pruritic inflammatory skin diseases, its influence on cutaneous inflammation and the interplay between inflammatory and neurosensory pathways remain unmapped. Here, we examined the consequences of disrupting Il31 and its receptor Il31ra in a mouse model of house dust mite (HDM)-induced allergic dermatitis. Il31-deficient mice displayed a deficit in HDM dermatitis-associated scratching, consistent with its well-established role as a pruritogen. In contrast, Il31 deficiency increased the number and proportion of cutaneous type 2 cytokine-producing CD4+ T cells and serum IgE in response to HDM. Furthermore, Il4ra+ monocytes and macrophages capable of fueling a feedforward type 2 inflammatory loop were selectively enriched in Il31ra-deficient HDM dermatitis skin. Thus, IL-31 is not strictly a proinflammatory cytokine but rather an immunoregulatory factor that limits the magnitude of type 2 inflammatory responses in skin. Our data support a model wherein IL-31 activation of IL31RA+ pruritoceptors triggers release of calcitonin gene-related protein (CGRP), which can mediate neurogenic inflammation, inhibit CD4+ T cell proliferation, and reduce T cell production of the type 2 cytokine IL-13. Together, these results illustrate a previously unrecognized neuroimmune pathway that constrains type 2 tissue inflammation in the setting of chronic cutaneous allergen exposure and may explain paradoxical dermatitis flares in atopic patients treated with anti-IL31RA therapy.
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Affiliation(s)
- Marlys S Fassett
- Department of Dermatology, University of California, San Francisco, CA, USA
- Department of Microbiology and Immunology, University of California, San Francisco, CA, USA
- Sandler Asthma Basic Research Center (SABRe), San Francisco, CA, USA
| | - Joao M Braz
- Department of Anatomy, University of California, San Francisco, CA, USA
| | - Carlos A Castellanos
- Department of Microbiology and Immunology, University of California, San Francisco, CA, USA
- Sandler Asthma Basic Research Center (SABRe), San Francisco, CA, USA
| | | | - Mahsa Sadeghi
- Department of Anatomy, University of California, San Francisco, CA, USA
| | - Xiaobing Yu
- Department of Anatomy, University of California, San Francisco, CA, USA
- Department of Anesthesiology, University of California, San Francisco, CA, USA
| | | | - Jaela Caston
- Department of Dermatology, University of California, San Francisco, CA, USA
- Department of Microbiology and Immunology, University of California, San Francisco, CA, USA
| | - Priscila Munoz-Sandoval
- Department of Dermatology, University of California, San Francisco, CA, USA
- Department of Microbiology and Immunology, University of California, San Francisco, CA, USA
- Sandler Asthma Basic Research Center (SABRe), San Francisco, CA, USA
- Howard Hughes Medical Institute, San Francisco, CA 94143, USA
| | - Suparna Roy
- Department of Dermatology, University of California, San Francisco, CA, USA
- Department of Microbiology and Immunology, University of California, San Francisco, CA, USA
- Sandler Asthma Basic Research Center (SABRe), San Francisco, CA, USA
| | - Steven Lazarevsky
- Department of Dermatology, University of California, San Francisco, CA, USA
| | - Darryl J Mar
- Department of Microbiology and Immunology, University of California, San Francisco, CA, USA
| | - Connie J Zhou
- Department of Microbiology and Immunology, University of California, San Francisco, CA, USA
| | - Jeoung-Sook Shin
- Department of Microbiology and Immunology, University of California, San Francisco, CA, USA
- Sandler Asthma Basic Research Center (SABRe), San Francisco, CA, USA
| | - Allan I Basbaum
- Department of Anatomy, University of California, San Francisco, CA, USA
| | - K Mark Ansel
- Department of Microbiology and Immunology, University of California, San Francisco, CA, USA
- Sandler Asthma Basic Research Center (SABRe), San Francisco, CA, USA
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7
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Singh I, Seth A, Billesbølle CB, Braz J, Rodriguiz RM, Roy K, Bekele B, Craik V, Huang XP, Boytsov D, Pogorelov VM, Lak P, O'Donnell H, Sandtner W, Irwin JJ, Roth BL, Basbaum AI, Wetsel WC, Manglik A, Shoichet BK, Rudnick G. Structure-based discovery of conformationally selective inhibitors of the serotonin transporter. Cell 2023; 186:2160-2175.e17. [PMID: 37137306 PMCID: PMC10306110 DOI: 10.1016/j.cell.2023.04.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Revised: 02/05/2023] [Accepted: 04/06/2023] [Indexed: 05/05/2023]
Abstract
The serotonin transporter (SERT) removes synaptic serotonin and is the target of anti-depressant drugs. SERT adopts three conformations: outward-open, occluded, and inward-open. All known inhibitors target the outward-open state except ibogaine, which has unusual anti-depressant and substance-withdrawal effects, and stabilizes the inward-open conformation. Unfortunately, ibogaine's promiscuity and cardiotoxicity limit the understanding of inward-open state ligands. We docked over 200 million small molecules against the inward-open state of the SERT. Thirty-six top-ranking compounds were synthesized, and thirteen inhibited; further structure-based optimization led to the selection of two potent (low nanomolar) inhibitors. These stabilized an outward-closed state of the SERT with little activity against common off-targets. A cryo-EM structure of one of these bound to the SERT confirmed the predicted geometry. In mouse behavioral assays, both compounds had anxiolytic- and anti-depressant-like activity, with potencies up to 200-fold better than fluoxetine (Prozac), and one substantially reversed morphine withdrawal effects.
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Affiliation(s)
- Isha Singh
- Department of Pharmaceutical Chemistry, University of California, San Francisco, 1700 4th St., Byers Hall Suite 508D, San Francisco, CA 94143, USA
| | - Anubha Seth
- Department of Pharmacology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520-8066, USA
| | - Christian B Billesbølle
- Department of Pharmaceutical Chemistry, University of California, San Francisco, 1700 4th St., Byers Hall Suite 508D, San Francisco, CA 94143, USA
| | - Joao Braz
- Department of Anatomy, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Ramona M Rodriguiz
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, NC 27710, USA; Mouse Behavioral and Neuroendocrine Analysis Core Facility, Duke University Medical Center, Durham, NC 27710, USA
| | - Kasturi Roy
- Department of Pharmacology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520-8066, USA
| | - Bethlehem Bekele
- Department of Pharmacology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520-8066, USA
| | - Veronica Craik
- Department of Anatomy, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Xi-Ping Huang
- Department of Pharmacology, NIMH Psychoactive Drug Screening Program, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Danila Boytsov
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, 1090 Vienna, Austria
| | - Vladimir M Pogorelov
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, NC 27710, USA
| | - Parnian Lak
- Department of Pharmaceutical Chemistry, University of California, San Francisco, 1700 4th St., Byers Hall Suite 508D, San Francisco, CA 94143, USA
| | - Henry O'Donnell
- Department of Pharmaceutical Chemistry, University of California, San Francisco, 1700 4th St., Byers Hall Suite 508D, San Francisco, CA 94143, USA
| | - Walter Sandtner
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, 1090 Vienna, Austria
| | - John J Irwin
- Department of Pharmaceutical Chemistry, University of California, San Francisco, 1700 4th St., Byers Hall Suite 508D, San Francisco, CA 94143, USA
| | - Bryan L Roth
- Department of Pharmacology, NIMH Psychoactive Drug Screening Program, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Allan I Basbaum
- Department of Anatomy, University of California, San Francisco, San Francisco, CA 94143, USA.
| | - William C Wetsel
- Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, NC 27710, USA; Mouse Behavioral and Neuroendocrine Analysis Core Facility, Duke University Medical Center, Durham, NC 27710, USA; Departments of Cell Biology and Neurobiology, Duke University Medical Center, Durham, NC 27710, USA.
| | - Aashish Manglik
- Department of Pharmaceutical Chemistry, University of California, San Francisco, 1700 4th St., Byers Hall Suite 508D, San Francisco, CA 94143, USA; Department of Anesthesia and Perioperative Care, University of California, San Francisco, San Francisco, CA 94115, USA.
| | - Brian K Shoichet
- Department of Pharmaceutical Chemistry, University of California, San Francisco, 1700 4th St., Byers Hall Suite 508D, San Francisco, CA 94143, USA.
| | - Gary Rudnick
- Department of Pharmacology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520-8066, USA.
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8
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Weinrich JA, Liu CD, Jewell ME, Andolina CR, Bernstein MX, Benitez J, Rodriguez-Rosado S, Braz JM, Maze M, Nemenov MI, Basbaum AI. Paradoxical increases in anterior cingulate cortex activity during nitrous oxide-induced analgesia reveal a signature of pain affect. bioRxiv 2023:2023.04.03.534475. [PMID: 37066151 PMCID: PMC10104003 DOI: 10.1101/2023.04.03.534475] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 04/26/2023]
Abstract
The general consensus is that increases in neuronal activity in the anterior cingulate cortex (ACC) contribute to pain's negative affect. Here, using in vivo imaging of neuronal calcium dynamics in mice, we report that nitrous oxide, a general anesthetic that reduces pain affect, paradoxically, increases ACC spontaneous activity. As expected, a noxious stimulus also increased ACC activity. However, as nitrous oxide increases baseline activity, the relative change in activity from pre-stimulus baseline was significantly less than the change in the absence of the general anesthetic. We suggest that this relative change in activity represents a neural signature of the affective pain experience. Furthermore, this signature of pain persists under general anesthesia induced by isoflurane, at concentrations in which the mouse is unresponsive. We suggest that this signature underlies the phenomenon of connected consciousness, in which use of the isolated forelimb technique revealed that pain percepts can persist in anesthetized patients.
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Affiliation(s)
- Jarret Ap Weinrich
- Department of Anatomy, University of California San Francisco, San Francisco, CA 94158, USA
| | - Cindy D Liu
- Department of Anatomy, University of California San Francisco, San Francisco, CA 94158, USA
- Neuroscience Graduate Program, University of California San Francisco, San Francisco, CA 94158, USA
| | - Madison E Jewell
- Department of Anatomy, University of California San Francisco, San Francisco, CA 94158, USA
| | - Christopher R Andolina
- Department of Anatomy, University of California San Francisco, San Francisco, CA 94158, USA
| | - Mollie X Bernstein
- Department of Anatomy, University of California San Francisco, San Francisco, CA 94158, USA
| | - Jorge Benitez
- Department of Anatomy, University of California San Francisco, San Francisco, CA 94158, USA
| | - Sian Rodriguez-Rosado
- Department of Anatomy, University of California San Francisco, San Francisco, CA 94158, USA
| | - Joao M Braz
- Department of Anatomy, University of California San Francisco, San Francisco, CA 94158, USA
| | - Mervyn Maze
- Department of Anesthesia and Perioperative Care, University of California San Francisco, San Francisco, CA 94158, USA
| | - Mikhail I Nemenov
- Lasmed, Mountain View, CA 94043, USA
- Department of Anesthesia, Stanford University School of Medicine, Stanford, CA 94035, USA
| | - Allan I Basbaum
- Department of Anatomy, University of California San Francisco, San Francisco, CA 94158, USA
- Neuroscience Graduate Program, University of California San Francisco, San Francisco, CA 94158, USA
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9
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Henn AT, Larsen B, Frahm L, Xu A, Adebimpe A, Scott JC, Linguiti S, Sharma V, Basbaum AI, Corder G, Dworkin RH, Edwards RR, Woolf CJ, Habel U, Eickhoff SB, Eickhoff CR, Wagels L, Satterthwaite TD. Structural imaging studies of patients with chronic pain: an anatomical likelihood estimate meta-analysis. Pain 2023; 164:e10-e24. [PMID: 35560117 PMCID: PMC9653511 DOI: 10.1097/j.pain.0000000000002681] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Accepted: 05/09/2022] [Indexed: 01/09/2023]
Abstract
ABSTRACT Neuroimaging is a powerful tool to investigate potential associations between chronic pain and brain structure. However, the proliferation of studies across diverse chronic pain syndromes and heterogeneous results challenges data integration and interpretation. We conducted a preregistered anatomical likelihood estimate meta-analysis on structural magnetic imaging studies comparing patients with chronic pain and healthy controls. Specifically, we investigated a broad range of measures of brain structure as well as specific alterations in gray matter and cortical thickness. A total of 7849 abstracts of experiments published between January 1, 1990, and April 26, 2021, were identified from 8 databases and evaluated by 2 independent reviewers. Overall, 103 experiments with a total of 5075 participants met the preregistered inclusion criteria. After correction for multiple comparisons using the gold-standard family-wise error correction ( P < 0.05), no significant differences associated with chronic pain were found. However, exploratory analyses using threshold-free cluster enhancement revealed several spatially distributed clusters showing structural alterations in chronic pain. Most of the clusters coincided with regions implicated in nociceptive processing including the amygdala, thalamus, hippocampus, insula, anterior cingulate cortex, and inferior frontal gyrus. Taken together, these results suggest that chronic pain is associated with subtle, spatially distributed alterations of brain structure.
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Affiliation(s)
- Alina T. Henn
- Department of Psychiatry, Psychotherapy and Psychosomatics, School of Medicine, RWTH Aachen University, Aachen, Germany
| | - Bart Larsen
- Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, US
- Lifespan Informatics and Neuroimaging Center, Perelman School of Medicine, University of Pennsylvania
| | - Lennart Frahm
- Institute of Neuroscience and Medicine (INM7), Forschungszentrum Jülich, Jülich, Germany
| | - Anna Xu
- Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, US
- Lifespan Informatics and Neuroimaging Center, Perelman School of Medicine, University of Pennsylvania
- Department of Psychology, Stanford University, Stanford, Carlifornia, US
| | - Azeez Adebimpe
- Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, US
- Lifespan Informatics and Neuroimaging Center, Perelman School of Medicine, University of Pennsylvania
| | - J. Cobb Scott
- Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, US
- VISN4 Mental Illness Research, Education, and Clinical Center at the Corporal Michael J. Crescenz VA (Veterans Affairs) Medical Center, Philadelphia, Pennsylvania, US
| | - Sophia Linguiti
- Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, US
- Lifespan Informatics and Neuroimaging Center, Perelman School of Medicine, University of Pennsylvania
| | - Vaishnavi Sharma
- Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, US
- Lifespan Informatics and Neuroimaging Center, Perelman School of Medicine, University of Pennsylvania
| | - Allan I. Basbaum
- Department of Anatomy, University of California, San Francisco, US
| | - Gregory Corder
- Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, US
| | - Robert H. Dworkin
- Department of Anesthesiology and Perioperative Medicine, University of Rochester School of Medicine and Dentistry, Rochester, New York, US
| | - Robert R. Edwards
- Department of Anesthesiology, Perioperative and Pain Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, US
| | - Clifford J. Woolf
- FM Kirby Neurobiology Center, Boston Children’s Hospital, Boston, Massachusetts, US
- Department of Neurobiology, Harvard Medical School, Boston, Massachusetts, US
| | - Ute Habel
- Department of Psychiatry, Psychotherapy and Psychosomatics, School of Medicine, RWTH Aachen University, Aachen, Germany
- JARA-Institute Brain Structure Function Relationship (INM 10), Research Center Jülich, Jülich, Germany
| | - Simon B. Eickhoff
- Institute of Neuroscience and Medicine (INM7), Forschungszentrum Jülich, Jülich, Germany
- Institute of Systems Neuroscience, Medical Faculty, Heinrich-Heine University, Düsseldorf, Germany
| | - Claudia R. Eickhoff
- Institute of Clinical Neuroscience and Medical Psychology, Medical Faculty, Heinrich-Heine-University, Düsseldorf, Germany
- Institute of Neuroscience and Medicine (INM1), Forschungszentrum Jülich, Jülich, Germany
| | - Lisa Wagels
- Department of Psychiatry, Psychotherapy and Psychosomatics, School of Medicine, RWTH Aachen University, Aachen, Germany
- JARA-Institute Brain Structure Function Relationship (INM 10), Research Center Jülich, Jülich, Germany
| | - Theodore D. Satterthwaite
- Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, US
- Lifespan Informatics and Neuroimaging Center, Perelman School of Medicine, University of Pennsylvania
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10
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Fink EA, Xu J, Hübner H, Braz JM, Seemann P, Avet C, Craik V, Weikert D, Schmidt MF, Webb CM, Tolmachova NA, Moroz YS, Huang XP, Kalyanaraman C, Gahbauer S, Chen G, Liu Z, Jacobson MP, Irwin JJ, Bouvier M, Du Y, Shoichet BK, Basbaum AI, Gmeiner P. Structure-based discovery of nonopioid analgesics acting through the α 2A-adrenergic receptor. Science 2022; 377:eabn7065. [PMID: 36173843 PMCID: PMC10360211 DOI: 10.1126/science.abn7065] [Citation(s) in RCA: 42] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Because nonopioid analgesics are much sought after, we computationally docked more than 301 million virtual molecules against a validated pain target, the α2A-adrenergic receptor (α2AAR), seeking new α2AAR agonists chemotypes that lack the sedation conferred by known α2AAR drugs, such as dexmedetomidine. We identified 17 ligands with potencies as low as 12 nanomolar, many with partial agonism and preferential Gi and Go signaling. Experimental structures of α2AAR complexed with two of these agonists confirmed the docking predictions and templated further optimization. Several compounds, including the initial docking hit '9087 [mean effective concentration (EC50) of 52 nanomolar] and two analogs, '7075 and PS75 (EC50 4.1 and 4.8 nanomolar), exerted on-target analgesic activity in multiple in vivo pain models without sedation. These newly discovered agonists are interesting as therapeutic leads that lack the liabilities of opioids and the sedation of dexmedetomidine.
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Affiliation(s)
- Elissa A. Fink
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA, USA
- Graduate Program in Biophysics, University of California, San Francisco, San Francisco, CA, USA
| | - Jun Xu
- Kobilka Institute of Innovative Drug Discovery, School of Life and Health Sciences, Chinese University of Hong Kong, Shenzhen, Guangdong 518172, China
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA, USA
| | - Harald Hübner
- Department of Chemistry and Pharmacy, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91058 Erlangen, Germany
| | - Joao M. Braz
- Department of Anatomy, University of California, San Francisco, San Francisco, CA, USA
| | - Philipp Seemann
- Department of Chemistry and Pharmacy, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91058 Erlangen, Germany
| | - Charlotte Avet
- Department of Biochemistry and Molecular Medicine, Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, QC, Canada
| | - Veronica Craik
- Department of Anatomy, University of California, San Francisco, San Francisco, CA, USA
| | - Dorothee Weikert
- Department of Chemistry and Pharmacy, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91058 Erlangen, Germany
| | - Maximilian F. Schmidt
- Department of Chemistry and Pharmacy, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91058 Erlangen, Germany
| | - Chase M. Webb
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA, USA
- Graduate Program in Pharmaceutical Sciences and Pharmacogenomics, University of California, San Francisco, San Francisco, CA, USA
| | - Nataliya A. Tolmachova
- Enamine Ltd., 02094 Kyiv, Ukraine
- Institute of Bioorganic Chemistry and Petrochemistry, National Ukrainian Academy of Science, 02660 Kyiv, Ukraine
| | - Yurii S. Moroz
- National Taras Shevchenko University of Kyiv, 01601 Kyiv, Ukraine
- Chemspace, Riga LV-1082, Latvia
| | - Xi-Ping Huang
- National Institute of Mental Health Psychoactive Drug Screening Program (NIMH PDSP), School of Medicine, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC, USA
| | - Chakrapani Kalyanaraman
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA, USA
| | - Stefan Gahbauer
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA, USA
| | - Geng Chen
- Kobilka Institute of Innovative Drug Discovery, School of Life and Health Sciences, Chinese University of Hong Kong, Shenzhen, Guangdong 518172, China
| | - Zheng Liu
- Kobilka Institute of Innovative Drug Discovery, School of Life and Health Sciences, Chinese University of Hong Kong, Shenzhen, Guangdong 518172, China
| | - Matthew P. Jacobson
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA, USA
| | - John J. Irwin
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA, USA
| | - Michel Bouvier
- Department of Biochemistry and Molecular Medicine, Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, QC, Canada
| | - Yang Du
- Kobilka Institute of Innovative Drug Discovery, School of Life and Health Sciences, Chinese University of Hong Kong, Shenzhen, Guangdong 518172, China
| | - Brian K. Shoichet
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA, USA
| | - Allan I. Basbaum
- Department of Anatomy, University of California, San Francisco, San Francisco, CA, USA
| | - Peter Gmeiner
- Department of Chemistry and Pharmacy, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91058 Erlangen, Germany
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11
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Yue WWS, Yuan L, Braz JM, Basbaum AI, Julius D. TRPV1 drugs alter core body temperature via central projections of primary afferent sensory neurons. eLife 2022; 11:e80139. [PMID: 35968676 PMCID: PMC9377796 DOI: 10.7554/elife.80139] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Accepted: 08/04/2022] [Indexed: 11/29/2022] Open
Abstract
TRPV1, a capsaicin- and heat-activated ion channel, is expressed by peripheral nociceptors and has been implicated in various inflammatory and neuropathic pain conditions. Although pharmacological modulation of TRPV1 has attracted therapeutic interest, many TRPV1 agonists and antagonists produce thermomodulatory side effects in animal models and human clinical trials, limiting their utility. These on-target effects may result from the perturbation of TRPV1 receptors on nociceptors, which transduce signals to central thermoregulatory circuits and release proinflammatory factors from their peripheral terminals, most notably the potent vasodilative neuropeptide, calcitonin gene-related peptide (CGRP). Alternatively, these body temperature effects may originate from the modulation of TRPV1 on vascular smooth muscle cells (vSMCs), where channel activation promotes arteriole constriction. Here, we ask which of these pathways is most responsible for the body temperature perturbations elicited by TRPV1 drugs in vivo. We address this question by selectively eliminating TRPV1 expression in sensory neurons or vSMCs and show that only the former abrogates agonist-induced hypothermia and antagonist-induced hyperthermia. Furthermore, lesioning the central projections of TRPV1-positive sensory nerve fibers also abrogates drug-mediated thermomodulation, whereas eliminating CGRP has no effect. Thus, TRPV1 drugs alter core body temperature by modulating sensory input to the central nervous system, rather than through peripheral actions on the vasculature. These findings suggest how mechanistically distinct TRPV1 antagonists may diminish inflammatory pain without affecting core body temperature.
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Affiliation(s)
- Wendy Wing Sze Yue
- Department of Physiology, University of CaliforniaSan FranciscoUnited States
| | - Lin Yuan
- Department of Physiology, University of CaliforniaSan FranciscoUnited States
| | - Joao M Braz
- Department of Anatomy, University of CaliforniaSan FranciscoUnited States
| | - Allan I Basbaum
- Department of Anatomy, University of CaliforniaSan FranciscoUnited States
| | - David Julius
- Department of Physiology, University of CaliforniaSan FranciscoUnited States
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12
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Levit Kaplan A, Strachan RT, Braz JM, Craik V, Slocum S, Mangano T, Amabo V, O'Donnell H, Lak P, Basbaum AI, Roth BL, Shoichet BK. Structure-Based Design of a Chemical Probe Set for the 5-HT 5A Serotonin Receptor. J Med Chem 2022; 65:4201-4217. [PMID: 35195401 DOI: 10.1021/acs.jmedchem.1c02031] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The 5-HT5A receptor (5-HT5AR), for which no selective agonists and a few antagonists exist, remains the least understood serotonin receptor. A single commercial antagonist, SB-699551, has been widely used to investigate the 5-HT5AR function in neurological disorders, including pain, but this molecule has substantial liabilities as a chemical probe. Accordingly, we sought to develop an internally controlled probe set. Docking over 6 million molecules against a 5-HT5AR homology model identified 5 mid-μM ligands, one of which was optimized to UCSF678, a 42 nM arrestin-biased partial agonist at the 5-HT5AR with a more restricted off-target profile and decreased assay liabilities versus SB-699551. Site-directed mutagenesis supported the docked pose of UCSF678. Surprisingly, analogs of UCSF678 that lost the 5-HT5AR activity revealed that 5-HT5AR engagement is nonessential for alleviating pain, contrary to studies with less-selective ligands. UCSF678 and analogs constitute a selective probe set with which to study the function of the 5-HT5AR.
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Affiliation(s)
- Anat Levit Kaplan
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, California 94143, United States
| | - Ryan T Strachan
- Department of Pharmacology, School of Medicine, University of North Carolina, Chapel Hill, Chapel Hill, North Carolina 27514, United States
| | - Joao M Braz
- Department of Anatomy, University of California, San Francisco, San Francisco, California 94143, United States
| | - Veronica Craik
- Department of Anatomy, University of California, San Francisco, San Francisco, California 94143, United States
| | - Samuel Slocum
- National Institute of Mental Health Psychoactive Drug Screening Program, School of Medicine, University of North Carolina, Chapel Hill, Chapel Hill, North Carolina 27514, United States
| | - Thomas Mangano
- National Institute of Mental Health Psychoactive Drug Screening Program, School of Medicine, University of North Carolina, Chapel Hill, Chapel Hill, North Carolina 27514, United States
| | - Vanessa Amabo
- National Institute of Mental Health Psychoactive Drug Screening Program, School of Medicine, University of North Carolina, Chapel Hill, Chapel Hill, North Carolina 27514, United States
| | - Henry O'Donnell
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, California 94143, United States
| | - Parnian Lak
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, California 94143, United States
| | - Allan I Basbaum
- Department of Anatomy, University of California, San Francisco, San Francisco, California 94143, United States
| | - Bryan L Roth
- Department of Pharmacology, School of Medicine, University of North Carolina, Chapel Hill, Chapel Hill, North Carolina 27514, United States.,National Institute of Mental Health Psychoactive Drug Screening Program, School of Medicine, University of North Carolina, Chapel Hill, Chapel Hill, North Carolina 27514, United States.,Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, Chapel Hill, North Carolina 27514, United States
| | - Brian K Shoichet
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, California 94143, United States
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13
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Wercberger R, Braz JM, Weinrich JA, Basbaum AI. Pain and itch processing by subpopulations of molecularly diverse spinal and trigeminal projection neurons. Proc Natl Acad Sci U S A 2021; 118:e2105732118. [PMID: 34234018 PMCID: PMC8285968 DOI: 10.1073/pnas.2105732118] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
A remarkable molecular and functional heterogeneity of the primary sensory neurons and dorsal horn interneurons transmits pain- and or itch-relevant information, but the molecular signature of the projection neurons that convey the messages to the brain is unclear. Here, using retro-TRAP (translating ribosome affinity purification) and RNA sequencing, we reveal extensive molecular diversity of spino- and trigeminoparabrachial projection neurons. Among the many genes identified, we highlight distinct subsets of Cck+ -, Nptx2+ -, Nmb+ -, and Crh+ -expressing projection neurons. By combining in situ hybridization of retrogradely labeled neurons with Fos-based assays, we also demonstrate significant functional heterogeneity, including both convergence and segregation of pain- and itch-provoking inputs into molecularly diverse subsets of NK1R- and non-NK1R-expressing projection neurons.
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Affiliation(s)
- Racheli Wercberger
- Department of Anatomy, University of California, San Francisco, CA 94158
| | - Joao M Braz
- Department of Anatomy, University of California, San Francisco, CA 94158
| | - Jarret A Weinrich
- Department of Anatomy, University of California, San Francisco, CA 94158
| | - Allan I Basbaum
- Department of Anatomy, University of California, San Francisco, CA 94158
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14
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Xu A, Larsen B, Henn A, Baller EB, Scott JC, Sharma V, Adebimpe A, Basbaum AI, Corder G, Dworkin RH, Edwards RR, Woolf CJ, Eickhoff SB, Eickhoff CR, Satterthwaite TD. Brain Responses to Noxious Stimuli in Patients With Chronic Pain: A Systematic Review and Meta-analysis. JAMA Netw Open 2021; 4:e2032236. [PMID: 33399857 PMCID: PMC7786252 DOI: 10.1001/jamanetworkopen.2020.32236] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
IMPORTANCE Functional neuroimaging is a valuable tool for understanding how patients with chronic pain respond to painful stimuli. However, past studies have reported heterogenous results, highlighting opportunities for a quantitative meta-analysis to integrate existing data and delineate consistent associations across studies. OBJECTIVE To identify differential brain responses to noxious stimuli in patients with chronic pain using functional magnetic resonance imaging (fMRI) while adhering to current best practices for neuroimaging meta-analyses. DATA SOURCES All fMRI experiments published from January 1, 1990, to May 28, 2019, were identified in a literature search of PubMed/MEDLINE, EMBASE, Web of Science, Cochrane Library, PsycINFO, and SCOPUS. STUDY SELECTION Experiments comparing brain responses to noxious stimuli in fMRI between patients and controls were selected if they reported whole-brain results, included at least 10 patients and 10 healthy control participants, and used adequate statistical thresholding (voxel-height P < .001 or cluster-corrected P < .05). Two independent reviewers evaluated titles and abstracts returned by the search. In total, 3682 abstracts were screened, and 1129 full-text articles were evaluated. DATA EXTRACTION AND SYNTHESIS Thirty-seven experiments from 29 articles met inclusion criteria for meta-analysis. Coordinates reporting significant activation differences between patients with chronic pain and healthy controls were extracted. These data were meta-analyzed using activation likelihood estimation. Data were analyzed from December 2019 to February 2020. MAIN OUTCOMES AND MEASURES A whole-brain meta-analysis evaluated whether reported differences in brain activation in response to noxious stimuli between patients and healthy controls were spatially convergent. Follow-up analyses examined the directionality of any differences. Finally, an exploratory (nonpreregistered) region-of-interest analysis examined differences within the pain network. RESULTS The 37 experiments from 29 unique articles included a total of 511 patients and 433 controls (944 participants). Whole-brain meta-analyses did not reveal significant differences between patients and controls in brain responses to noxious stimuli at the preregistered statistical threshold. However, exploratory analyses restricted to the pain network revealed aberrant activity in patients. CONCLUSIONS AND RELEVANCE In this systematic review and meta-analysis, preregistered, whole-brain analyses did not reveal aberrant fMRI activity in patients with chronic pain. Exploratory analyses suggested that subtle, spatially diffuse differences may exist within the pain network. Future work on chronic pain biomarkers may benefit from focus on this core set of pain-responsive areas.
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Affiliation(s)
- Anna Xu
- Department of Psychiatry, University of Pennsylvania, Philadelphia
| | - Bart Larsen
- Department of Psychiatry, University of Pennsylvania, Philadelphia
| | - Alina Henn
- Department of Psychiatry, Psychotherapy and Psychosomatics, Medical Faculty, RWTH (Rheinisch-Westfälische Technische Hochschule) Aachen University, Aachen, Germany
| | - Erica B. Baller
- Department of Psychiatry, University of Pennsylvania, Philadelphia
- Department of Psychiatry, Massachusetts General Hospital, Boston
- Department of Psychiatry, Harvard University, Boston, Massachusetts
| | - J. Cobb Scott
- Department of Psychiatry, University of Pennsylvania, Philadelphia
- VISN4 Mental Illness Research, Education, and Clinical Center at the Corporal Michael J. Crescenz VA (Veterans Affairs) Medical Center, Philadelphia, Pennsylvania
| | - Vaishnavi Sharma
- Department of Psychiatry, University of Pennsylvania, Philadelphia
| | - Azeez Adebimpe
- Department of Psychiatry, University of Pennsylvania, Philadelphia
| | | | - Gregory Corder
- Department of Psychiatry, University of Pennsylvania, Philadelphia
| | - Robert H. Dworkin
- Department of Anesthesiology and Perioperative Medicine, University of Rochester School of Medicine and Dentistry, Rochester, New York
| | - Robert R. Edwards
- Department of Anesthesiology, Perioperative and Pain Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts
| | - Clifford J. Woolf
- FM Kirby Neurobiology Center, Boston Children’s Hospital, Boston, Massachusetts
- Department of Neurobiology, Harvard Medical School, Boston, Massachusetts
| | - Simon B. Eickhoff
- Institute of Systems Neuroscience, Medical Faculty, Heinrich-Heine University, Düsseldorf, Germany
- Institute of Neuroscience and Medicine, Brain and Behaviour Sections, Research Centre Jülich, Jülich, Germany
| | - Claudia R. Eickhoff
- Institute of Neuroscience and Medicine, Brain and Behaviour Sections, Research Centre Jülich, Jülich, Germany
- Institute of Clinical Neuroscience and Medical Psychology, Medical Faculty, Heinrich-Heine-University, Düsseldorf, Germany
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15
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Tran M, Braz JM, Hamel K, Kuhn J, Todd AJ, Basbaum AI. Ablation of spinal cord estrogen receptor α-expressing interneurons reduces chemically induced modalities of pain and itch. J Comp Neurol 2020; 528:1629-1643. [PMID: 31872868 PMCID: PMC7317200 DOI: 10.1002/cne.24847] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Revised: 12/13/2019] [Accepted: 12/16/2019] [Indexed: 11/13/2022]
Abstract
Estrogens are presumed to underlie, at least in part, the greater pain sensitivity and chronic pain prevalence that women experience compared to men. Although previous studies revealed populations of estrogen receptor-expressing neurons in primary afferents and in superficial dorsal horn neurons, there is little to no information as to the contribution of these neurons to the generation of acute and chronic pain. Here we molecularly characterized neurons in the mouse superficial spinal cord dorsal horn that express estrogen receptor α (ERα) and explored the behavioral consequences of their ablation. We found that spinal ERα-positive neurons are largely excitatory interneurons and many coexpress substance P, a marker for a discrete subset of nociceptive, excitatory interneurons. After viral, caspase-mediated ablation of spinal ERα-expressing cells, we observed a significant decrease in the first phase of the formalin test, but in male mice only. ERα-expressing neuron-ablation also reduced pruritogen-induced scratching in both male and female mice. There were no ablation-related changes in mechanical or heat withdrawal thresholds or in capsaicin-induced nocifensive behavior. In chronic pain models, we found no change in Complete Freund's adjuvant-induced thermal or mechanical hypersensitivity, or in partial sciatic nerve injury-induced mechanical allodynia. We conclude that ERα labels a subpopulation of excitatory interneurons that are specifically involved in chemically evoked persistent pain and pruritogen-induced itch.
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Affiliation(s)
- May Tran
- Department of AnatomyUniversity of CaliforniaSan FranciscoCalifornia
| | - Joao Manuel Braz
- Department of AnatomyUniversity of CaliforniaSan FranciscoCalifornia
| | - Katherine Hamel
- Department of AnatomyUniversity of CaliforniaSan FranciscoCalifornia
| | - Julia Kuhn
- Department of AnatomyUniversity of CaliforniaSan FranciscoCalifornia
| | - Andrew J. Todd
- Spinal Cord Group, Institute of Neuroscience and Psychology, College of Medical, Veterinary and Life SciencesUniversity of GlasgowGlasgowUK
| | - Allan I. Basbaum
- Department of AnatomyUniversity of CaliforniaSan FranciscoCalifornia
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16
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Alvaro CG, Braz JM, Bernstein M, Hamel KA, Craik V, Yamanaka H, Basbaum AI. Hippocalcin-like 4, a neural calcium sensor, has a limited contribution to pain and itch processing. PLoS One 2020; 15:e0226289. [PMID: 32015563 PMCID: PMC6996964 DOI: 10.1371/journal.pone.0226289] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Accepted: 11/22/2019] [Indexed: 11/19/2022] Open
Abstract
Calcium binding proteins are expressed throughout the central and peripheral nervous system and disruption of their activity has major consequences in a wide array of cellular processes, including transmission of nociceptive signals that are processed at the level of the spinal cord. We previously reported that the calcium binding protein, hippocalcin-like 4 (Hpcal4), is heavily expressed in interneurons of the superficial dorsal horn, and that its expression is significantly downregulated in a TR4 mutant mouse model that exhibits major pain and itch deficits due to loss of a subpopulation of excitatory interneurons. That finding suggested that Hpcal4 may be a contributor to the behavioral phenotype of the TR4 mutant mouse. To address this question, here we investigated the behavioral consequences of global deletion of Hpcal4 in a battery of acute and persistent pain and itch tests. Unexpectedly, with the exception of a mild reduction in acute baseline thermal responses, Hpcal4-deficient mice exhibit no major deficits in pain or itch responses, under normal conditions or in the setting of tissue or nerve injury. Taken together, our results indicate that the neural calcium sensor Hpcal4 likely makes a limited contribution to pain and itch processing.
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Affiliation(s)
- Christopher G. Alvaro
- Department of Anatomy, University of California, San Francisco, CA, United States of America
| | - João M. Braz
- Department of Anatomy, University of California, San Francisco, CA, United States of America
| | - Mollie Bernstein
- Department of Anatomy, University of California, San Francisco, CA, United States of America
| | - Katherine A. Hamel
- Department of Anatomy, University of California, San Francisco, CA, United States of America
| | - Veronica Craik
- Department of Anatomy, University of California, San Francisco, CA, United States of America
| | - Hiroki Yamanaka
- Department of Anatomy, University of California, San Francisco, CA, United States of America
- Department of Anatomy and Neuroscience, Hyogo College of Medicine, Hyogo, Japan
| | - Allan I. Basbaum
- Department of Anatomy, University of California, San Francisco, CA, United States of America
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17
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Xu A, Larsen B, Baller EB, Scott JC, Sharma V, Adebimpe A, Basbaum AI, Dworkin RH, Edwards RR, Woolf CJ, Eickhoff SB, Eickhoff CR, Satterthwaite TD. Convergent neural representations of experimentally-induced acute pain in healthy volunteers: A large-scale fMRI meta-analysis. Neurosci Biobehav Rev 2020; 112:300-323. [PMID: 31954149 DOI: 10.1016/j.neubiorev.2020.01.004] [Citation(s) in RCA: 52] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Revised: 12/17/2019] [Accepted: 01/03/2020] [Indexed: 02/06/2023]
Abstract
Characterizing a reliable, pain-related neural signature is critical for translational applications. Many prior fMRI studies have examined acute nociceptive pain-related brain activation in healthy participants. However, synthesizing these data to identify convergent patterns of activation can be challenging due to the heterogeneity of experimental designs and samples. To address this challenge, we conducted a comprehensive meta-analysis of fMRI studies of stimulus-induced pain in healthy participants. Following pre-registration, two independent reviewers evaluated 4,927 abstracts returned from a search of 8 databases, with 222 fMRI experiments meeting inclusion criteria. We analyzed these experiments using Activation Likelihood Estimation with rigorous type I error control (voxel height p < 0.001, cluster p < 0.05 FWE-corrected) and found a convergent, largely bilateral pattern of pain-related activation in the secondary somatosensory cortex, insula, midcingulate cortex, and thalamus. Notably, these regions were consistently recruited regardless of stimulation technique, location of induction, and participant sex. These findings suggest a highly-conserved core set of pain-related brain areas, encouraging applications as a biomarker for novel therapeutics targeting acute nociceptive pain.
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Affiliation(s)
- Anna Xu
- Department of Psychiatry, University of Pennsylvania, Philadelphia PA 19104, USA
| | - Bart Larsen
- Department of Psychiatry, University of Pennsylvania, Philadelphia PA 19104, USA
| | - Erica B Baller
- Department of Psychiatry, University of Pennsylvania, Philadelphia PA 19104, USA; Department of Psychiatry, Massachusetts General Hospital, Boston, MA, USA; Department of Psychiatry, Harvard University, Boston, MA, USA
| | - J Cobb Scott
- Department of Psychiatry, University of Pennsylvania, Philadelphia PA 19104, USA; VISN4 Mental Illness Research, Education, and Clinical Center at the Philadelphia VA Medical Center, Philadelphia, PA, 19104, USA
| | - Vaishnavi Sharma
- Department of Psychiatry, University of Pennsylvania, Philadelphia PA 19104, USA
| | - Azeez Adebimpe
- Department of Psychiatry, University of Pennsylvania, Philadelphia PA 19104, USA
| | - Allan I Basbaum
- Department of Anatomy, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Robert H Dworkin
- Department of Anesthesiology and Perioperative Medicine, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA
| | - Robert R Edwards
- Department of Anesthesiology, Perioperative and Pain Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Clifford J Woolf
- FM Kirby Neurobiology Center, Boston Children's Hospital and Department of Neurobiology, Harvard Medical School, Boston, MA, USA
| | - Simon B Eickhoff
- Institute of Systems Neuroscience, Medical Faculty, Heinrich-Heine University, D-40225 Düsseldorf, Germany; Institute of Neuroscience and Medicine, Brain & Behaviour (INM-1, INM-7), Research Centre Jülich, Germany
| | - Claudia R Eickhoff
- Institute of Neuroscience and Medicine, Brain & Behaviour (INM-1, INM-7), Research Centre Jülich, Germany; Institute of Clinical Neuroscience and Medical Psychology, Medical Faculty, Heinrich-Heine-University, 40225 Düsseldorf, Germany
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18
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Yu X, Liu H, Hamel KA, Morvan MG, Yu S, Leff J, Guan Z, Braz JM, Basbaum AI. Dorsal root ganglion macrophages contribute to both the initiation and persistence of neuropathic pain. Nat Commun 2020; 11:264. [PMID: 31937758 PMCID: PMC6959328 DOI: 10.1038/s41467-019-13839-2] [Citation(s) in RCA: 221] [Impact Index Per Article: 55.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Accepted: 11/27/2019] [Indexed: 12/12/2022] Open
Abstract
Paralleling the activation of dorsal horn microglia after peripheral nerve injury is a significant expansion and proliferation of macrophages around injured sensory neurons in dorsal root ganglia (DRG). Here we demonstrate a critical contribution of DRG macrophages, but not those at the nerve injury site, to both the initiation and maintenance of the mechanical hypersensitivity that characterizes the neuropathic pain phenotype. In contrast to the reported sexual dimorphism in the microglial contribution to neuropathic pain, depletion of DRG macrophages reduces nerve injury-induced mechanical hypersensitivity and expansion of DRG macrophages in both male and female mice. However, fewer macrophages are induced in the female mice and deletion of colony-stimulating factor 1 from sensory neurons, which prevents nerve injury-induced microglial activation and proliferation, only reduces macrophage expansion in male mice. Finally, we demonstrate molecular cross-talk between axotomized sensory neurons and macrophages, revealing potential peripheral DRG targets for neuropathic pain management. Interactions among spinal dorsal horn neurons and microglia contribute to the induction and maintenance of neuropathic pain after peripheral nerve injury. The authors show that depletion of macrophages in the dorsal root ganglia prevents and reverses ongoing nerve injury-induced hypersensitivity.
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Affiliation(s)
- Xiaobing Yu
- Department of Anesthesia and Perioperative Care, University of California San Francisco, San Francisco, California, USA.
| | - Hongju Liu
- Department of Anesthesia and Perioperative Care, University of California San Francisco, San Francisco, California, USA.,Department of Anesthesiology, Peking Union Medical College Hospital, Beijing, China
| | - Katherine A Hamel
- Department of Anatomy, University of California San Francisco, San Francisco, California, USA
| | - Maelig G Morvan
- Department of Medicine, University of California San Francisco, San Francisco, California, USA
| | - Stephen Yu
- Department of Anatomy, University of California San Francisco, San Francisco, California, USA
| | - Jacqueline Leff
- Department of Anesthesia and Perioperative Care, University of California San Francisco, San Francisco, California, USA
| | - Zhonghui Guan
- Department of Anesthesia and Perioperative Care, University of California San Francisco, San Francisco, California, USA
| | - Joao M Braz
- Department of Anatomy, University of California San Francisco, San Francisco, California, USA
| | - Allan I Basbaum
- Department of Anatomy, University of California San Francisco, San Francisco, California, USA.
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19
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Abstract
Today there are extensive maps of the molecular heterogeneity of primary afferents and dorsal horn interneurons, yet there is a dearth of molecular and functional information regarding the projection neurons that transmit pain and itch information to the brain. Additionally, most contemporary research into the spinal cord and medullary projection neurons focuses on neurons in the superficial dorsal horn; the contribution of deep dorsal horn and even ventral horn projection neurons to pain and itch processing is often overlooked. In the present review we integrate conclusions from classical as well as contemporary studies and provide a more balanced view of the diversity of projection neurons. A major question addressed is the extent to which labeled-lines are maintained in these different populations or whether the brain generates distinct pain and itch percepts by decoding complex convergent inputs that engage projection neurons.
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Affiliation(s)
- Racheli Wercberger
- Department of Anatomy and Neuroscience Graduate Program, University California San Francisco, San Francisco, CA 94158
| | - Allan I Basbaum
- Department of Anatomy and Neuroscience Graduate Program, University California San Francisco, San Francisco, CA 94158
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20
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Juarez-Salinas DL, Braz JM, Etlin A, Gee S, Sohal V, Basbaum AI. GABAergic cell transplants in the anterior cingulate cortex reduce neuropathic pain aversiveness. Brain 2019; 142:2655-2669. [PMID: 31321411 PMCID: PMC6752168 DOI: 10.1093/brain/awz203] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Revised: 03/18/2019] [Accepted: 05/12/2019] [Indexed: 01/09/2023] Open
Abstract
Dysfunction of inhibitory circuits in the rostral anterior cingulate cortex underlies the affective (aversive), but not the sensory-discriminative features (hypersensitivity) of the pain experience. To restore inhibitory controls, we transplanted inhibitory interneuron progenitor cells into the rostral anterior cingulate cortex in a chemotherapy-induced neuropathic pain model. The transplants integrated, exerted a GABA-A mediated inhibition of host pyramidal cells and blocked gabapentin preference (i.e. relieved ongoing pain) in a conditioned place preference paradigm. Surprisingly, pain aversiveness persisted when the transplants populated both the rostral and posterior anterior cingulate cortex. We conclude that selective and long lasting inhibition of the rostral anterior cingulate cortex, in the mouse, has a profound pain relieving effect against nerve injury-induced neuropathic pain. However, the interplay between the rostral and posterior anterior cingulate cortices must be considered when examining circuits that influence ongoing pain and pain aversiveness.
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Affiliation(s)
| | - Joao M Braz
- Department Anatomy, University California San Francisco, San Francisco, CA, USA
| | - Alexander Etlin
- Department Anatomy, University California San Francisco, San Francisco, CA, USA
| | - Steven Gee
- Department Psychiatry, University California San Francisco, San Francisco, CA, USA
| | - Vikaas Sohal
- Department Psychiatry, University California San Francisco, San Francisco, CA, USA
| | - Allan I Basbaum
- Department Anatomy, University California San Francisco, San Francisco, CA, USA
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21
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Price TJ, Basbaum AI, Bresnahan J, Chambers JF, De Koninck Y, Edwards RR, Ji RR, Katz J, Kavelaars A, Levine JD, Porter L, Schechter N, Sluka KA, Terman GW, Wager TD, Yaksh TL, Dworkin RH. Transition to chronic pain: opportunities for novel therapeutics. Nat Rev Neurosci 2019; 19:383-384. [PMID: 29765159 DOI: 10.1038/s41583-018-0012-5] [Citation(s) in RCA: 88] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
| | - Allan I Basbaum
- University of California, San Francisco, San Francisco, CA, USA
| | | | - Jan F Chambers
- National Fibromyalgia and Chronic Pain Association, Logan, UT, USA
| | - Yves De Koninck
- Laval University & CERVO Brain Research Centre, Québec, QC, Canada
| | | | | | - Joel Katz
- York University, Toronto, ON, Canada
| | | | - Jon D Levine
- University of California, San Francisco, San Francisco, CA, USA
| | - Linda Porter
- National Institutes of Health, Bethesda, MD, USA
| | | | | | | | | | - Tony L Yaksh
- University of California, San Diego, San Diego, CA, USA
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22
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Wang X, Yvone GM, Cilluffo M, Kim AS, Basbaum AI, Phelps PE. Mispositioned Neurokinin-1 Receptor-Expressing Neurons Underlie Heat Hyperalgesia in Disabled-1 Mutant Mice. eNeuro 2019; 6:ENEURO.0131-19.2019. [PMID: 31122949 PMCID: PMC6584071 DOI: 10.1523/eneuro.0131-19.2019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Revised: 05/11/2019] [Accepted: 05/15/2019] [Indexed: 11/30/2022] Open
Abstract
Reelin (Reln) and Disabled-1 (Dab1) participate in the Reln-signaling pathway and when either is deleted, mutant mice have the same spinally mediated behavioral abnormalities, increased sensitivity to noxious heat and a profound loss in mechanical sensitivity. Both Reln and Dab1 are highly expressed in dorsal horn areas that receive and convey nociceptive information, Laminae I-II, lateral Lamina V, and the lateral spinal nucleus (LSN). Lamina I contains both projection neurons and interneurons that express Neurokinin-1 receptors (NK1Rs) and they transmit information about noxious heat both within the dorsal horn and to the brain. Here, we ask whether the increased heat nociception in Reln and dab1 mutants is due to incorrectly positioned dorsal horn neurons that express NK1Rs. We found more NK1R-expressing neurons in Reln-/- and dab1-/- Laminae I-II than in their respective wild-type mice, and some NK1R neurons co-expressed Dab1 and the transcription factor Lmx1b, confirming their excitatory phenotype. Importantly, heat stimulation in dab1-/- mice induced Fos in incorrectly positioned NK1R neurons in Laminae I-II. Next, we asked whether these ectopically placed and noxious-heat responsive NK1R neurons participated in pain behavior. Ablation of the superficial NK1Rs with an intrathecal injection of a substance P analog conjugated to the toxin saporin (SSP-SAP) eliminated the thermal hypersensitivity of dab1-/- mice, without altering their mechanical insensitivity. These results suggest that ectopically positioned NK1R-expressing neurons underlie the heat hyperalgesia of Reelin-signaling pathway mutants, but do not contribute to their profound mechanical insensitivity.
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Affiliation(s)
- Xidao Wang
- Departments of Anatomy and Physiology and W. M. Keck Foundation Center for Integrative Neuroscience, University of California, San Francisco, CA 94158
| | - Griselda M Yvone
- Department of Integrative Biology and Physiology UCLA, Los Angeles, Los Angeles, CA 90095
| | - Marianne Cilluffo
- Department of Integrative Biology and Physiology UCLA, Los Angeles, Los Angeles, CA 90095
| | - Ashley S Kim
- Department of Integrative Biology and Physiology UCLA, Los Angeles, Los Angeles, CA 90095
| | - Allan I Basbaum
- Departments of Anatomy and Physiology and W. M. Keck Foundation Center for Integrative Neuroscience, University of California, San Francisco, CA 94158
| | - Patricia E Phelps
- Department of Integrative Biology and Physiology UCLA, Los Angeles, Los Angeles, CA 90095
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23
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Meda KS, Patel T, Braz JM, Malik R, Turner ML, Seifikar H, Basbaum AI, Sohal VS. Microcircuit Mechanisms through which Mediodorsal Thalamic Input to Anterior Cingulate Cortex Exacerbates Pain-Related Aversion. Neuron 2019; 102:944-959.e3. [PMID: 31030955 PMCID: PMC6554049 DOI: 10.1016/j.neuron.2019.03.042] [Citation(s) in RCA: 93] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Revised: 01/21/2019] [Accepted: 03/27/2019] [Indexed: 02/05/2023]
Abstract
Hyperexcitability of the anterior cingulate cortex (ACC) is thought to drive aversion associated with chronic neuropathic pain. Here, we studied the contribution of input from the mediodorsal thalamus (MD) to ACC, using sciatic nerve injury and chemotherapy-induced mouse models of neuropathic pain. Activating MD inputs elicited pain-related aversion in both models. Unexpectedly, excitatory responses of layer V ACC neurons to MD inputs were significantly weaker in pain models compared to controls. This caused the ratio between excitation and feedforward inhibition elicited by MD input to shift toward inhibition, specifically for subcortically projecting (SC) layer V neurons. Furthermore, direct inhibition of SC neurons reproduced the pain-related aversion elicited by activating MD inputs. Finally, both the ability to elicit pain-related aversion and the decrease in excitation were specific to MD inputs; activating basolateral amygdala inputs produced opposite effects. Thus, chronic pain-related aversion may reflect activity changes in specific pathways, rather than generalized ACC hyperactivity.
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Affiliation(s)
- Karuna S Meda
- Department of Anatomy and Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Tosha Patel
- Department of Psychiatry, Weill Institute for Neurosciences and Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Joao M Braz
- Department of Anatomy and Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Ruchi Malik
- Department of Psychiatry, Weill Institute for Neurosciences and Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Marc L Turner
- Department of Psychiatry, Weill Institute for Neurosciences and Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Helia Seifikar
- Department of Psychiatry, Weill Institute for Neurosciences and Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Allan I Basbaum
- Department of Anatomy and Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, San Francisco, CA 94143, USA.
| | - Vikaas S Sohal
- Department of Psychiatry, Weill Institute for Neurosciences and Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, San Francisco, CA 94143, USA.
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24
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Braz JM, Etlin A, Juarez-Salinas D, Llewellyn-Smith IJ, Basbaum AI. Rebuilding CNS inhibitory circuits to control chronic neuropathic pain and itch. Prog Brain Res 2018; 231:87-105. [PMID: 28554402 DOI: 10.1016/bs.pbr.2016.10.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Cell transplantation offers an attractive alternative to pharmacotherapy for the management of a host of clinical conditions. Most importantly, the transplanted cells provide a continuous, local delivery of therapeutic compounds, which avoids many of the adverse side effects associated with systemically administered drugs. Here, we describe the broad therapeutic utility of transplanting precursors of cortical inhibitory interneurons derived from the embryonic medial ganglionic eminence (MGE), in a variety of chronic pain and itch models in the mouse. Despite the cortical environment in which the MGE cells normally develop, these cells survive transplantation and will even integrate into the circuitry of an adult host spinal cord. When transplanted into the spinal cord, the cells significantly reduce the hyperexcitability that characterizes both chronic neuropathic pain and itch conditions. This MGE cell-based strategy differs considerably from traditional pharmacological treatments as the approach is potentially disease modifying (i.e., the therapy targets the underlying etiology of the pain and itch pathophysiology).
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Affiliation(s)
- Joao M Braz
- University of California-San Francisco, San Francisco, CA, United States
| | - Alex Etlin
- University of California-San Francisco, San Francisco, CA, United States
| | | | - Ida J Llewellyn-Smith
- Cardiovascular Medicine, Human Physiology and Centre for Neuroscience, Flinders University, Bedford Park, SA, Australia
| | - Allan I Basbaum
- University of California-San Francisco, San Francisco, CA, United States.
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25
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Wang D, Tawfik VL, Corder G, Low SA, François A, Basbaum AI, Scherrer G. Functional Divergence of Delta and Mu Opioid Receptor Organization in CNS Pain Circuits. Neuron 2018; 98:90-108.e5. [PMID: 29576387 PMCID: PMC5896237 DOI: 10.1016/j.neuron.2018.03.002] [Citation(s) in RCA: 97] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Revised: 01/19/2018] [Accepted: 03/02/2018] [Indexed: 12/21/2022]
Abstract
Cellular interactions between delta and mu opioid receptors (DORs and MORs), including heteromerization, are thought to regulate opioid analgesia. However, the identity of the nociceptive neurons in which such interactions could occur in vivo remains elusive. Here we show that DOR-MOR co-expression is limited to small populations of excitatory interneurons and projection neurons in the spinal cord dorsal horn and unexpectedly predominates in ventral horn motor circuits. Similarly, DOR-MOR co-expression is rare in parabrachial, amygdalar, and cortical brain regions processing nociceptive information. We further demonstrate that in the discrete DOR-MOR co-expressing nociceptive neurons, the two receptors internalize and function independently. Finally, conditional knockout experiments revealed that DORs selectively regulate mechanical pain by controlling the excitability of somatostatin-positive dorsal horn interneurons. Collectively, our results illuminate the functional organization of DORs and MORs in CNS pain circuits and reappraise the importance of DOR-MOR cellular interactions for developing novel opioid analgesics.
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MESH Headings
- Animals
- Anterior Horn Cells/chemistry
- Anterior Horn Cells/metabolism
- Anterior Horn Cells/pathology
- Central Nervous System/chemistry
- Central Nervous System/metabolism
- Central Nervous System/pathology
- Male
- Mice, Inbred C57BL
- Mice, Knockout
- Nerve Net/chemistry
- Nerve Net/metabolism
- Nerve Net/pathology
- Pain/metabolism
- Pain/pathology
- Pain Measurement/methods
- Posterior Horn Cells/chemistry
- Posterior Horn Cells/metabolism
- Posterior Horn Cells/pathology
- Receptors, Opioid, delta/biosynthesis
- Receptors, Opioid, delta/genetics
- Receptors, Opioid, mu/biosynthesis
- Receptors, Opioid, mu/genetics
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Affiliation(s)
- Dong Wang
- Department of Anesthesiology, Perioperative and Pain Medicine, Stanford University, Palo Alto, CA 94304, USA; Department of Molecular and Cellular Physiology, Stanford University, Palo Alto, CA 94304, USA; Department of Neurosurgery, Stanford University, Palo Alto, CA 94304, USA; Stanford Neurosciences Institute, Stanford University, Palo Alto, CA 94304, USA
| | - Vivianne L Tawfik
- Department of Anesthesiology, Perioperative and Pain Medicine, Stanford University, Palo Alto, CA 94304, USA; Department of Molecular and Cellular Physiology, Stanford University, Palo Alto, CA 94304, USA; Department of Neurosurgery, Stanford University, Palo Alto, CA 94304, USA; Stanford Neurosciences Institute, Stanford University, Palo Alto, CA 94304, USA
| | - Gregory Corder
- Department of Anesthesiology, Perioperative and Pain Medicine, Stanford University, Palo Alto, CA 94304, USA; Department of Molecular and Cellular Physiology, Stanford University, Palo Alto, CA 94304, USA; Department of Neurosurgery, Stanford University, Palo Alto, CA 94304, USA; Stanford Neurosciences Institute, Stanford University, Palo Alto, CA 94304, USA
| | - Sarah A Low
- Department of Anesthesiology, Perioperative and Pain Medicine, Stanford University, Palo Alto, CA 94304, USA; Department of Molecular and Cellular Physiology, Stanford University, Palo Alto, CA 94304, USA; Department of Neurosurgery, Stanford University, Palo Alto, CA 94304, USA; Stanford Neurosciences Institute, Stanford University, Palo Alto, CA 94304, USA
| | - Amaury François
- Department of Anesthesiology, Perioperative and Pain Medicine, Stanford University, Palo Alto, CA 94304, USA; Department of Molecular and Cellular Physiology, Stanford University, Palo Alto, CA 94304, USA; Department of Neurosurgery, Stanford University, Palo Alto, CA 94304, USA; Stanford Neurosciences Institute, Stanford University, Palo Alto, CA 94304, USA
| | - Allan I Basbaum
- Department of Anatomy, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Grégory Scherrer
- Department of Anesthesiology, Perioperative and Pain Medicine, Stanford University, Palo Alto, CA 94304, USA; Department of Molecular and Cellular Physiology, Stanford University, Palo Alto, CA 94304, USA; Department of Neurosurgery, Stanford University, Palo Alto, CA 94304, USA; Stanford Neurosciences Institute, Stanford University, Palo Alto, CA 94304, USA; New York Stem Cell Foundation - Robertson Investigator, Stanford University, Palo Alto, CA 94304, USA.
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26
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Llewellyn-Smith IJ, Basbaum AI, Bráz JM. Long-term, dynamic synaptic reorganization after GABAergic precursor cell transplantation into adult mouse spinal cord. J Comp Neurol 2017; 526:480-495. [PMID: 29134656 DOI: 10.1002/cne.24346] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Revised: 10/04/2017] [Accepted: 10/06/2017] [Indexed: 12/14/2022]
Abstract
Transplanting embryonic precursors of GABAergic neurons from the medial ganglionic eminence (MGE) into adult mouse spinal cord ameliorates mechanical and thermal hypersensitivity in peripheral nerve injury models of neuropathic pain. Although Fos and transneuronal tracing studies strongly suggest that integration of MGE-derived neurons into host spinal cord circuits underlies recovery of function, the extent to which there is synaptic integration of the transplanted cells has not been established. Here, we used electron microscopic immunocytochemistry to assess directly integration of GFP-expressing MGE-derived neuronal precursors into dorsal horn circuitry in intact, adult mice with short- (5-6 weeks) or long-term (4-6 months) transplants. We detected GFP with pre-embedding avidin-biotin-peroxidase and GABA with post-embedding immunogold labeling. At short and long times post-transplant, we found host-derived synapses on GFP-immunoreactive MGE cells bodies and dendrites. The proportion of dendrites with synaptic input increased from 50% to 80% by 6 months. In all mice, MGE-derived terminals formed synapses with GFP-negative (host) cell bodies and dendrites and, unexpectedly, with some GFP-positive (i.e., MGE-derived) dendrites, possibly reflecting autoapses or cross talk among transplanted neurons. We also observed axoaxonic appositions between MGE and host terminals. Immunogold labeling for GABA confirmed that the transplanted cells were GABAergic and that some transplanted cells received an inhibitory GABAergic input. We conclude that transplanted MGE neurons retain their GABAergic phenotype and integrate dynamically into host-transplant synaptic circuits. Taken together with our previous electrophysiological analyses, we conclude that MGE cells are not GABA pumps, but alleviate pain and itch through synaptic release of GABA.
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Affiliation(s)
- Ida J Llewellyn-Smith
- Cardiovascular Medicine, Human Physiology and Centre for Neuroscience, College of Medicine and Public Health, Flinders University, Bedford Park, South Australia, Australia.,Department of Anatomy, University of California San Francisco, San Francisco, California
| | - Allan I Basbaum
- Department of Anatomy, University of California San Francisco, San Francisco, California
| | - João M Bráz
- Department of Anatomy, University of California San Francisco, San Francisco, California
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27
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Tran M, Kuhn JA, Bráz JM, Basbaum AI. Neuronal aromatase expression in pain processing regions of the medullary and spinal cord dorsal horn. J Comp Neurol 2017. [PMID: 28649695 DOI: 10.1002/cne.24269] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
In both acute and chronic pain conditions, women tend to be more sensitive than men. This sex difference may be regulated by estrogens, such as estradiol, that are synthesized in the spinal cord and brainstem and act locally to influence pain processing. To identify a potential cellular source of local estrogen, here we examined the expression of aromatase, the enzyme that catalyzes the conversion of testosterone to estradiol. Our studies focused on primary afferent neurons and on their central targets in the spinal cord and medulla as well as in the nucleus of the solitary tract, the target of nodose ganglion-derived visceral afferents. Immunohistochemical staining in an aromatase reporter mouse revealed that many neurons in laminae I and V of the spinal cord dorsal horn and caudal spinal trigeminal nucleus and in the nucleus of the solitary tract express aromatase. The great majority of these cells also express inhibitory interneuron markers. We did not find sex differences in aromatase expression and neither the pattern nor the number of neurons changed in a sciatic nerve transection model of neuropathic pain or in the Complete Freund's adjuvant model of inflammatory pain. A few aromatase neurons express Fos after cheek injection of capsaicin, formalin, or chloroquine. In total, given their location, these aromatase neurons are poised to engage nociceptive circuits, whether it is through local estrogen synthesis or inhibitory neurotransmitter release.
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Affiliation(s)
- May Tran
- Department of Anatomy, University of California, San Francisco, San Francisco, California
| | - Julia A Kuhn
- Department of Anatomy, University of California, San Francisco, San Francisco, California
| | - João M Bráz
- Department of Anatomy, University of California, San Francisco, San Francisco, California
| | - Allan I Basbaum
- Department of Anatomy, University of California, San Francisco, San Francisco, California
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28
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Frezel N, Sohet F, Daneman R, Basbaum AI, Braz JM. Peripheral and central neuronal ATF3 precedes CD4+ T-cell infiltration in EAE. Exp Neurol 2016; 283:224-34. [PMID: 27343802 DOI: 10.1016/j.expneurol.2016.06.019] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Revised: 06/15/2016] [Accepted: 06/20/2016] [Indexed: 01/04/2023]
Abstract
Experimental allergic encephalomyelitis (EAE), an animal model of multiple sclerosis produced by immunization with myelin oligodendrocyte glycoprotein (MOG) and adjuvants, results from profound T-cell mediated CNS demyelination. EAE is characterized by progressive, ascending motor dysfunction and symptoms of ongoing pain and hypersensitivity, in some cases preceding or concomitant with the motor deficits. In this regard, the EAE model mimics major features of multiple sclerosis, where a central neuropathic pain state is common. Although the latter condition is presumed to arise from a CNS loss of inhibitory controls secondary to the demyelination, dysfunction of sensory neurons may also contribute. Based on our previous studies that demonstrated the utility of monitoring expression of activating transcription factor 3 (ATF3), a sensitive marker of injured sensory neurons, here we followed both ATF3 and CD4+ T cells invasion of sensory ganglia (as well as the CNS) at different stages of the EAE model. We found that ATF3 is induced in peripheral sensory ganglia and brainstem well before the appearance of motor deficits. Unexpectedly, the ATF3 induction always preceded T cell infiltration, typically in adjacent, but non-overlapping regions. Surprisingly, control administration of the pertussis toxin and/or Complete Freund's adjuvants, without MOG, induced ATF3 in sensory neurons. In contrast, T cell infiltration only occurred with MOG. Taken together, our results suggest that the clinical manifestations in the EAE result not only from central demyelination but also from neuronal stress and subsequent pathophysiology of sensory neurons.
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Affiliation(s)
- Noémie Frezel
- Department Anatomy, University California San Francisco, San Francisco, CA 94158, United States.
| | - Fabien Sohet
- Department Anatomy, University California San Francisco, San Francisco, CA 94158, United States.
| | - Richard Daneman
- Department Anatomy, University California San Francisco, San Francisco, CA 94158, United States.
| | - Allan I Basbaum
- Department Anatomy, University California San Francisco, San Francisco, CA 94158, United States.
| | - Joao M Braz
- Department Anatomy, University California San Francisco, San Francisco, CA 94158, United States.
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29
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Brown JD, Saeed M, Do L, Braz J, Basbaum AI, Iadarola MJ, Wilson DM, Dillon WP. CT-guided injection of a TRPV1 agonist around dorsal root ganglia decreases pain transmission in swine. Sci Transl Med 2016; 7:305ra145. [PMID: 26378245 DOI: 10.1126/scitranslmed.aac6589] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
One approach to analgesia is to block pain at the site of origin or along the peripheral pathway by selectively ablating pain-transmitting neurons or nerve terminals directly. The heat/capsaicin receptor (TRPV1) expressed by nociceptive neurons is a compelling target for selective interventional analgesia because it leaves somatosensory and proprioceptive neurons intact. Resiniferatoxin (RTX), like capsaicin, is a TRPV1 agonist but has greater potency. We combine RTX-mediated inactivation with the precision of computed tomography (CT)-guided delivery to ablate peripheral pain fibers in swine. Under CT guidance, RTX was delivered unilaterally around the lumbar dorsal root ganglia (DRG), and vehicle only was administered to the contralateral side. During a 4-week observation period, animals demonstrated delayed or absent withdrawal responses to infrared laser heat stimuli delivered to sensory dermatomes corresponding to DRG receiving RTX treatment. Motor function was unimpaired as assessed by disability scoring and gait analysis. In treated DRG, TRPV1 mRNA expression was reduced, as were nociceptive neuronal perikarya in ganglia and their nerve terminals in the ipsilateral dorsal horn. CT guidance to precisely deliver RTX to sites of peripheral pain transmission in swine may be an approach that could be tailored to block an array of clinical pain conditions in patients.
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Affiliation(s)
- Jacob D Brown
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA 94117, USA
| | - Maythem Saeed
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA 94117, USA
| | - Loi Do
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA 94117, USA
| | - Joao Braz
- Department of Anatomy, University of California, San Francisco, San Francisco, CA 94117, USA
| | - Allan I Basbaum
- Department of Anatomy, University of California, San Francisco, San Francisco, CA 94117, USA
| | - Michael J Iadarola
- Department of Perioperative Medicine, Clinical Center, National Institutes of Health, Bethesda, MD 20892, USA
| | - David M Wilson
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA 94117, USA
| | - William P Dillon
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA 94117, USA.
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Petitjean H, Pawlowski SA, Fraine SL, Sharif B, Hamad D, Fatima T, Berg J, Brown CM, Jan LY, Ribeiro-da-Silva A, Braz JM, Basbaum AI, Sharif-Naeini R. Dorsal Horn Parvalbumin Neurons Are Gate-Keepers of Touch-Evoked Pain after Nerve Injury. Cell Rep 2015; 13:1246-1257. [PMID: 26527000 PMCID: PMC6038918 DOI: 10.1016/j.celrep.2015.09.080] [Citation(s) in RCA: 194] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Revised: 09/04/2015] [Accepted: 09/25/2015] [Indexed: 01/01/2023] Open
Abstract
Neuropathic pain is a chronic debilitating disease that results from nerve damage, persists long after the injury has subsided, and is characterized by spontaneous pain and mechanical hypersensitivity. Although loss of inhibitory tone in the dorsal horn of the spinal cord is a major contributor to neuropathic pain, the molecular and cellular mechanisms underlying this disinhibition are unclear. Here, we combined pharmacogenetic activation and selective ablation approaches in mice to define the contribution of spinal cord parvalbumin (PV)-expressing inhibitory interneurons in naive and neuropathic pain conditions. Ablating PV neurons in naive mice produce neuropathic pain-like mechanical allodynia via disinhibition of PKCγ excitatory interneurons. Conversely, activating PV neurons in nerve-injured mice alleviates mechanical hypersensitivity. These findings indicate that PV interneurons are modality-specific filters that gate mechanical but not thermal inputs to the dorsal horn and that increasing PV inter-neuron activity can ameliorate the mechanical hypersensitivity that develops following nerve injury.
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Affiliation(s)
- Hugues Petitjean
- Department of Physiology and Cell Information Systems Group, McGill University, Montreal, H3G0B1 QC, Canada
| | | | - Steven Li Fraine
- Department of Physiology and Cell Information Systems Group, McGill University, Montreal, H3G0B1 QC, Canada
| | - Behrang Sharif
- Department of Physiology and Cell Information Systems Group, McGill University, Montreal, H3G0B1 QC, Canada
| | - Doulia Hamad
- Department of Physiology and Cell Information Systems Group, McGill University, Montreal, H3G0B1 QC, Canada
| | - Tarheen Fatima
- Department of Physiology and Cell Information Systems Group, McGill University, Montreal, H3G0B1 QC, Canada
| | - Jim Berg
- Departments of Physiology and Biochemistry, Howard Hughes Medical Institute, University of California, San Francisco, 1550 4th Street, RH-490D, San Francisco, CA 94158, USA
| | - Claire M Brown
- Department of Physiology and Cell Information Systems Group, McGill University, Montreal, H3G0B1 QC, Canada; Advanced BioImaging Facility, McGill University, H3G0B1 QC, Canada
| | - Lily-Yeh Jan
- Departments of Physiology and Biochemistry, Howard Hughes Medical Institute, University of California, San Francisco, 1550 4th Street, RH-490D, San Francisco, CA 94158, USA
| | - Alfredo Ribeiro-da-Silva
- Department of Pharmacology and Therapeutics, McGill University, H3G1Y6 QC, Canada; Department of Anatomy and Cell Biology, McGill University, H3A0C7 QC, Canada
| | - Joao M Braz
- Department of Anatomy, University of California, San Francisco, 1550 4th Street, RH-348E, San Francisco, CA 94158, USA
| | - Allan I Basbaum
- Department of Anatomy, University of California, San Francisco, 1550 4th Street, RH-348E, San Francisco, CA 94158, USA
| | - Reza Sharif-Naeini
- Department of Physiology and Cell Information Systems Group, McGill University, Montreal, H3G0B1 QC, Canada.
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31
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Bráz JM, Wang F, Basbaum AI. Presynaptic Inputs to Any CNS Projection Neuron Identified by Dual Recombinant Virus Infection. PLoS One 2015; 10:e0140681. [PMID: 26470056 PMCID: PMC4607402 DOI: 10.1371/journal.pone.0140681] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Accepted: 09/29/2015] [Indexed: 12/24/2022] Open
Abstract
Although neuroanatomical tracing studies have defined the origin and targets of major projection neurons (PN) of the central nervous system (CNS), there is much less information about the circuits that influence these neurons. Recently, genetic approaches that use Cre recombinase-dependent viral vectors have greatly facilitated such circuit analysis, but these tracing approaches are limited by the availability of Cre-expressing mouse lines and the difficulty in restricting Cre expression to discrete regions of the CNS. Here, we illustrate an alternative approach to drive Cre expression specifically in defined subsets of CNS projection neurons, so as to map both direct and indirect presynaptic inputs to these cells. The method involves a combination of Cre-dependent transneuronal viral tracers that can be used in the adult and that does not require genetically modified mice. To trigger Cre-expression we inject a Cre-expressing adenovirus that is retrogradely transported to the projection neurons of interest. The region containing the retrogradely labeled projection neurons is next injected with Cre-dependent pseudorabies or rabies vectors, which results in labeling of poly- and monosynaptic neuronal inputs, respectively. In proof-of-concept experiments, we used this novel tracing system to study the circuits that engage projection neurons of the superficial dorsal horn of the spinal cord and trigeminal nucleus caudalis, neurons of the parabrachial nucleus of the dorsolateral pons that project to the amygdala and cortically-projecting neurons of the lateral geniculate nucleus. Importantly, because this dual viral tracing method does not require genetically derived Cre-expressing mouse lines, inputs to almost any projection system can be studied and the analysis can be performed in larger animals, such as the rat.
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Affiliation(s)
- João M. Bráz
- Department of Anatomy, University of California San Francisco, San Francisco, CA, 94143, United States of America
| | - Fan Wang
- Department of Cell Biology, Duke University, Durham, NC, 27710, United States of America
| | - Allan I. Basbaum
- Department of Anatomy, University of California San Francisco, San Francisco, CA, 94143, United States of America
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Braz JM, Juarez-Salinas D, Ross SE, Basbaum AI. Transplant restoration of spinal cord inhibitory controls ameliorates neuropathic itch. J Clin Invest 2014; 124:3612-6. [PMID: 25003193 DOI: 10.1172/jci75214] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Accepted: 05/29/2014] [Indexed: 01/02/2023] Open
Abstract
The transmission of pruritoceptive (itch) messages involves specific neural circuits within the spinal cord that are distinct from those that transmit pain messages. These itch-specific circuits are tonically regulated by inhibitory interneurons in the dorsal horn. Consistent with these findings, it has previously been reported that loss of GABAergic interneurons in mice harboring a deletion of the transcription factor Bhlhb5 generates a severe, nonremitting condition of chronic itch. Here, we tested the hypothesis that the neuropathic itch in BHLHB5-deficient animals can be treated by restoring inhibitory controls through spinal cord transplantation and integration of precursors of cortical inhibitory interneurons derived from the embryonic medial ganglionic eminence. We specifically targeted the transplants to segments of the spinal cord innervated by areas of the body that were most severely affected. BHLHB5-deficient mice that received transplants demonstrated a substantial reduction of excessive scratching and dramatic resolution of skin lesions. In contrast, the scratching persisted and skin lesions worsened over time in sham-treated mice. Together, these results indicate that cell-mediated restoration of inhibitory controls has potential as a powerful, cell-based therapy for neuropathic itch that not only ameliorates symptoms of chronic itch, but also may modify disease.
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Braz J, Solorzano C, Wang X, Basbaum AI. Transmitting pain and itch messages: a contemporary view of the spinal cord circuits that generate gate control. Neuron 2014; 82:522-36. [PMID: 24811377 DOI: 10.1016/j.neuron.2014.01.018] [Citation(s) in RCA: 292] [Impact Index Per Article: 29.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The original formulation of Gate Control Theory (GCT) proposed that the perception of pain produced by spinal cord signaling to the brain depends on a balance of activity generated in large (nonnociceptive)- and small (nociceptive)-diameter primary afferent fibers. The theory proposed that activation of the large-diameter afferent "closes" the gate by engaging a superficial dorsal horn interneuron that inhibits the firing of projection neurons. Activation of the nociceptors "opens" the gate through concomitant excitation of projection neurons and inhibition of the inhibitory interneurons. Sixty years after publication of the GCT, we are faced with an ever-growing list of morphologically and neurochemically distinct spinal cord interneurons. The present Review highlights the complexity of superficial dorsal horn circuitry and addresses the question whether the premises outlined in GCT still have relevance today. By examining the dorsal horn circuits that underlie the transmission of "pain" and "itch" messages, we also address the extent to which labeled lines can be incorporated into a contemporary view of GCT.
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Affiliation(s)
- João Braz
- Department of Anatomy, University California, San Francisco, San Francisco, CA 94158, USA
| | - Carlos Solorzano
- Department of Anatomy, University California, San Francisco, San Francisco, CA 94158, USA
| | - Xidao Wang
- Department of Anatomy, University California, San Francisco, San Francisco, CA 94158, USA
| | - Allan I Basbaum
- Department of Anatomy, University California, San Francisco, San Francisco, CA 94158, USA.
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Southwell DG, Nicholas CR, Basbaum AI, Stryker MP, Kriegstein AR, Rubenstein JL, Alvarez-Buylla A. Interneurons from embryonic development to cell-based therapy. Science 2014; 344:1240622. [PMID: 24723614 DOI: 10.1126/science.1240622] [Citation(s) in RCA: 134] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Many neurologic and psychiatric disorders are marked by imbalances between neural excitation and inhibition. In the cerebral cortex, inhibition is mediated largely by GABAergic (γ-aminobutyric acid-secreting) interneurons, a cell type that originates in the embryonic ventral telencephalon and populates the cortex through long-distance tangential migration. Remarkably, when transplanted from embryos or in vitro culture preparations, immature interneurons disperse and integrate into host brain circuits, both in the cerebral cortex and in other regions of the central nervous system. These features make interneuron transplantation a powerful tool for the study of neurodevelopmental processes such as cell specification, cell death, and cortical plasticity. Moreover, interneuron transplantation provides a novel strategy for modifying neural circuits in rodent models of epilepsy, Parkinson's disease, mood disorders, and chronic pain.
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Affiliation(s)
- Derek G Southwell
- Department of Neurological Surgery, University of California, San Francisco, CA 94143, USA
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35
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Bardoni R, Tawfik VL, Wang D, François A, Solorzano C, Shuster SA, Choudhury P, Betelli C, Cassidy C, Smith K, de Nooij JC, Mennicken F, O'Donnell D, Kieffer BL, Woodbury CJ, Basbaum AI, MacDermott AB, Scherrer G. Delta Opioid Receptors Presynaptically Regulate Cutaneous Mechanosensory Neuron Input to the Spinal Cord Dorsal Horn. Neuron 2014; 81:1443. [PMID: 28898633 DOI: 10.1016/j.neuron.2014.03.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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36
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Bardoni R, Tawfik VL, Wang D, François A, Solorzano C, Shuster SA, Choudhury P, Betelli C, Cassidy C, Smith K, de Nooij JC, Mennicken F, O'Donnell D, Kieffer BL, Woodbury CJ, Basbaum AI, MacDermott AB, Scherrer G. Delta opioid receptors presynaptically regulate cutaneous mechanosensory neuron input to the spinal cord dorsal horn. Neuron 2014; 81:1312-1327. [PMID: 24583022 DOI: 10.1016/j.neuron.2014.01.044] [Citation(s) in RCA: 102] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/16/2014] [Indexed: 11/24/2022]
Abstract
Cutaneous mechanosensory neurons detect mechanical stimuli that generate touch and pain sensation. Although opioids are generally associated only with the control of pain, here we report that the opioid system in fact broadly regulates cutaneous mechanosensation, including touch. This function is predominantly subserved by the delta opioid receptor (DOR), which is expressed by myelinated mechanoreceptors that form Meissner corpuscles, Merkel cell-neurite complexes, and circumferential hair follicle endings. These afferents also include a small population of CGRP-expressing myelinated nociceptors that we now identify as the somatosensory neurons that coexpress mu and delta opioid receptors. We further demonstrate that DOR activation at the central terminals of myelinated mechanoreceptors depresses synaptic input to the spinal dorsal horn, via the inhibition of voltage-gated calcium channels. Collectively our results uncover a molecular mechanism by which opioids modulate cutaneous mechanosensation and provide a rationale for targeting DOR to alleviate injury-induced mechanical hypersensitivity.
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Affiliation(s)
- Rita Bardoni
- Department of Biomedical, Metabolic and Neural Science, University of Modena and Reggio Emilia, 41100 Modena, Italy
| | - Vivianne L Tawfik
- Department of Anesthesiology, Perioperative and Pain Medicine, Department of Molecular and Cellular Physiology, Stanford Neurosciences Institute, Stanford University, Palo Alto, CA 94304, USA
| | - Dong Wang
- Department of Anesthesiology, Perioperative and Pain Medicine, Department of Molecular and Cellular Physiology, Stanford Neurosciences Institute, Stanford University, Palo Alto, CA 94304, USA
| | - Amaury François
- Department of Anesthesiology, Perioperative and Pain Medicine, Department of Molecular and Cellular Physiology, Stanford Neurosciences Institute, Stanford University, Palo Alto, CA 94304, USA
| | - Carlos Solorzano
- Department of Anatomy, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Scott A Shuster
- Department of Anesthesiology, Perioperative and Pain Medicine, Department of Molecular and Cellular Physiology, Stanford Neurosciences Institute, Stanford University, Palo Alto, CA 94304, USA
| | - Papiya Choudhury
- Department of Physiology and Cellular Biophysics, Department of Neuroscience, Columbia University, New York, NY 10032, USA
| | - Chiara Betelli
- Department of Biomedical, Metabolic and Neural Science, University of Modena and Reggio Emilia, 41100 Modena, Italy
| | - Colleen Cassidy
- Graduate Program in Neuroscience, University of Wyoming, Laramie, WY 82071, USA; Department of Zoology and Physiology, University of Wyoming, Laramie, WY 82071, USA
| | - Kristen Smith
- Graduate Program in Neuroscience, University of Wyoming, Laramie, WY 82071, USA; Department of Zoology and Physiology, University of Wyoming, Laramie, WY 82071, USA
| | - Joriene C de Nooij
- Departments of Neuroscience and Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA
| | - Françoise Mennicken
- AstraZeneca R&D Montreal, Department of Translational Science, Montreal, QC H4S 1Z9, Canada
| | - Dajan O'Donnell
- AstraZeneca R&D Montreal, Department of Translational Science, Montreal, QC H4S 1Z9, Canada
| | - Brigitte L Kieffer
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, UMR7104 CNRS/Université de Strasbourg, U964 INSERM, 67400 Illkirch, France
| | - C Jeffrey Woodbury
- Department of Zoology and Physiology, University of Wyoming, Laramie, WY 82071, USA
| | - Allan I Basbaum
- Department of Anatomy, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Amy B MacDermott
- Department of Physiology and Cellular Biophysics, Department of Neuroscience, Columbia University, New York, NY 10032, USA
| | - Grégory Scherrer
- Department of Anesthesiology, Perioperative and Pain Medicine, Department of Molecular and Cellular Physiology, Stanford Neurosciences Institute, Stanford University, Palo Alto, CA 94304, USA.
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37
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Mandadi S, Hong P, Tran MA, Bráz JM, Colarusso P, Basbaum AI, Whelan PJ. Identification of multisegmental nociceptive afferents that modulate locomotor circuits in the neonatal mouse spinal cord. J Comp Neurol 2014; 521:2870-87. [PMID: 23436436 DOI: 10.1002/cne.23321] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2012] [Revised: 02/08/2013] [Accepted: 02/11/2013] [Indexed: 11/06/2022]
Abstract
Compared to proprioceptive afferent collateral projections, less is known about the anatomical, neurochemical, and functional basis of nociceptive collateral projections modulating lumbar central pattern generators (CPG). Quick response times are critical to ensure rapid escape from aversive stimuli. Furthermore, sensitization of nociceptive afferent pathways can contribute to a pathological activation of motor circuits. We investigated the extent and role of collaterals of capsaicin-sensitive nociceptive sacrocaudal afferent (nSCA) nerves that directly ascend several spinal segments in Lissauer's tract and the dorsal column and regulate motor activity. Anterograde tracing demonstrated direct multisegmental projections of the sacral dorsal root 4 (S4) afferent collaterals in Lissauer's tract and in the dorsal column. Subsets of the traced S4 afferent collaterals expressed transient receptor potential vanilloid 1 (TRPV1), which transduces a nociceptive response to capsaicin. Electrophysiological data revealed that S4 dorsal root stimulation could evoke regular rhythmic bursting activity, and our data suggested that capsaicin-sensitive collaterals contribute to CPG activation across multiple segments. Capsaicin's effect on S4-evoked locomotor activity was potent until the lumbar 5 (L5) segments, and diminished in rostral segments. Using calcium imaging we found elevated calcium transients within Lissauer's tract and dorsal column at L5 segments when compared to the calcium transients only within the dorsal column at the lumbar 2 (L2) segments, which were desensitized by capsaicin. We conclude that lumbar locomotor networks in the neonatal mouse spinal cord are targets for modulation by direct multisegmental nSCA, subsets of which express TRPV1 in Lissauer's tract and the dorsal column. J. Comp. Neurol. 521:2870-2887, 2013. © 2013 Wiley Periodicals, Inc.
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Affiliation(s)
- Sravan Mandadi
- Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, T2N 4N1, Canada; Department of Physiology and Pharmacology, University of Calgary, Calgary, Alberta, T2N 4N1, Canada
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Huang F, Wang X, Ostertag EM, Nuwal T, Huang B, Jan YN, Basbaum AI, Jan LY. TMEM16C facilitates Na(+)-activated K+ currents in rat sensory neurons and regulates pain processing. Nat Neurosci 2013; 16:1284-90. [PMID: 23872594 PMCID: PMC4034143 DOI: 10.1038/nn.3468] [Citation(s) in RCA: 94] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2013] [Accepted: 06/09/2013] [Indexed: 01/28/2023]
Abstract
TMEM16C belongs to the TMEM16 family, which includes the Ca2+-activated Cl– channels (CaCCs) TMEM16A and TMEM16B and a small conductance Ca2+-activated, non-selective cation channel (SCAN), TMEM16F. Here we report that in rat dorsal root ganglia (DRG) TMEM16C is expressed mainly in the IB4 positive, non-peptidergic nociceptors that also express the sodium-activated potassium (KNa) channel Slack. Together these channel proteins promote KNa channel activity and dampen neuronal excitability. DRG from TMEM16C knock out rats have reduced Slack expression, broadened action potential and increased excitability. Moreover, the TMEM16C knock out rats as well as rats with Slack knockdown via intrathecal injection of siRNA exhibit increased thermal and mechanical sensitivity. Experiments involving heterologous expression in HEK293 cells further show that TMEM16C modulates the single channel activity of Slack channels and increases its sodium sensitivity. Our study thus reveals that TMEM16C enhances KNa channel activity in DRG neurons and regulate the processing of pain messages.
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Affiliation(s)
- Fen Huang
- Department of Physiology, University of California, San Francisco, San Francisco, California, USA
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39
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Wang X, Zhang J, Eberhart D, Urban R, Meda K, Solorzano C, Yamanaka H, Rice D, Basbaum AI. Excitatory superficial dorsal horn interneurons are functionally heterogeneous and required for the full behavioral expression of pain and itch. Neuron 2013; 78:312-24. [PMID: 23622066 DOI: 10.1016/j.neuron.2013.03.001] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/01/2013] [Indexed: 10/26/2022]
Abstract
To what extent dorsal horn interneurons contribute to the modality specific processing of pain and itch messages is not known. Here, we report that loxp/cre-mediated CNS deletion of TR4, a testicular orphan nuclear receptor, results in loss of many excitatory interneurons in the superficial dorsal horn but preservation of primary afferents and spinal projection neurons. The interneuron loss is associated with a near complete absence of supraspinally integrated pain and itch behaviors, elevated mechanical withdrawal thresholds and loss of nerve injury-induced mechanical hypersensitivity, but reflex responsiveness to noxious heat, nerve injury-induced heat hypersensitivity, and tissue injury-induced heat and mechanical hypersensitivity are intact. We conclude that different subsets of dorsal horn excitatory interneurons contribute to tissue and nerve injury-induced heat and mechanical pain and that the full expression of supraspinally mediated pain and itch behaviors cannot be generated solely by nociceptor and pruritoceptor activation of projection neurons; concurrent activation of excitatory interneurons is essential.
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Affiliation(s)
- Xidao Wang
- Departments of Anatomy and Physiology, University of California, San Francisco, San Francisco, CA 94158, USA
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40
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Gibbs JL, Urban R, Basbaum AI. Paradoxical surrogate markers of dental injury-induced pain in the mouse. Pain 2013; 154:1358-67. [PMID: 23719574 DOI: 10.1016/j.pain.2013.04.018] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2012] [Revised: 04/01/2013] [Accepted: 04/09/2013] [Indexed: 12/29/2022]
Abstract
Dental pain, including toothache, is one of the most prevalent types of orofacial pain, causing severe, persistent pain that has a significant negative effect on quality of life, including eating disturbances, mood changes, and sleep disruption. As the primary cause of toothache pain is injury to the uniquely innervated dental pulp, rodent models of this injury provide the opportunity to study neurobiological mechanisms of tissue injury-induced persistent pain. Here we evaluated behavioral changes in mice with a dental pulp injury (DPI) produced by mechanically exposing the pulp to the oral environment. We monitored the daily life behaviors of mice with DPI, including measures of eating, drinking, and movement. During the first 48 hours, the only parameter affected by DPI was locomotion, which was reduced. There was also a significant short-term decrease in the amount of weight gained by DPI animals that was not related to food consumption. As cold allodynia is frequently observed in individuals experiencing toothache pain, we tested whether mice with DPI demonstrate an aversion to drinking cold liquids using a cold-sucrose consumption test. Surprisingly, mice with DPI increased their consumption of sucrose solution, to over 150% of baseline, regardless of temperature. Both the weight loss and increased sucrose intake in the first 2 days of injury were reversed by administration of indomethacin. These findings indicate that enhanced sucrose consumption may be a reliable measure of orofacial pain in rodents, and suggest that alterations in energy expenditure and motivational behaviors are under-recognized outcomes of tooth injury.
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Affiliation(s)
- Jennifer L Gibbs
- Department of Preventive and Restorative Dental Sciences, Division of Endodontics, UCSF School of Dentistry, San Francisco, CA, USA.
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41
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Zhang J, Cavanaugh DJ, Nemenov MI, Basbaum AI. The modality-specific contribution of peptidergic and non-peptidergic nociceptors is manifest at the level of dorsal horn nociresponsive neurons. J Physiol 2012; 591:1097-110. [PMID: 23266932 DOI: 10.1113/jphysiol.2012.242115] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
We previously demonstrated that genetic and/or pharmacological ablation of the TRPV1+/peptidergic or the MrgprD+/non-peptidergic subset of nociceptors produced selective, modality-specific deficits in the behavioural responses to heat and mechanical stimuli, respectively. To assess whether this modality-specific contribution is also manifest at the level of spinal cord neuron responsiveness, here we made extracellular recordings from lumbar dorsal horn neurons of the mouse in response to graded thermal and mechanical stimulation. We found that, following intrathecal injection of capsaicin to eliminate the central terminals of TRPV1+ nociceptors, neurons in the region of laminae I and V of the spinal cord lost responsiveness to noxious heat (whether generated by a contact heat probe or diode laser), with no change in their response to noxious mechanical stimulation. In contrast, ablation of MrgprD+ afferents did not alter the response to noxious heat, but reduced the firing of superficial dorsal horn nociceptive-specific neurons in response to graded mechanical stimulation and decreased the relative number of wide dynamic range neurons that were exclusively mechanosensitive. Neither ablation procedure reduced the number of dorsal horn neurons that responded to noxious cold. These findings support the conclusion that TRPV1+ nociceptors are necessary and probably sufficient for noxious heat activation of dorsal horn neurons and that, despite their polymodal properties, TRPV1+ and MrgprD+ nociceptors provide modality-specific contributions to the response properties of spinal cord neurons.
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Affiliation(s)
- Jie Zhang
- Department of Anatomy, University of California San Francisco, San Francisco, CA 94158, USA
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42
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Bráz JM, Sharif-Naeini R, Vogt D, Kriegstein A, Alvarez-Buylla A, Rubenstein JL, Basbaum AI. Forebrain GABAergic neuron precursors integrate into adult spinal cord and reduce injury-induced neuropathic pain. Neuron 2012; 74:663-75. [PMID: 22632725 DOI: 10.1016/j.neuron.2012.02.033] [Citation(s) in RCA: 131] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/21/2012] [Indexed: 10/28/2022]
Abstract
Neuropathic pain is a chronic debilitating disease characterized by mechanical allodynia and spontaneous pain. Because symptoms are often unresponsive to conventional methods of pain treatment, new therapeutic approaches are essential. Here, we describe a strategy that not only ameliorates symptoms of neuropathic pain but is also potentially disease modifying. We show that transplantation of immature telencephalic GABAergic interneurons from the mouse medial ganglionic eminence (MGE) into the adult mouse spinal cord completely reverses the mechanical hypersensitivity produced by peripheral nerve injury. Underlying this improvement is a remarkable integration of the MGE transplants into the host spinal cord circuitry, in which the transplanted cells make functional connections with both primary afferent and spinal cord neurons. By contrast, MGE transplants were not effective against inflammatory pain. Our findings suggest that MGE-derived GABAergic interneurons overcome the spinal cord hyperexcitability that is a hallmark of nerve injury-induced neuropathic pain.
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Affiliation(s)
- João M Bráz
- Department of Anatomy, W.M. Keck Foundation Center for Integrative Neuroscience, University of California, San Francisco, San Francisco, CA 94158, USA.
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Chesler AT, Bohlen CJ, Sharif-Naeini R, Medzihradszky KF, Zhou S, King D, Sánchez EE, Burlingame AL, Basbaum AI, Julius D. A Novel Toxin that Targets Acid-Sensing Ion Channels to Produce Pain. Biophys J 2012. [DOI: 10.1016/j.bpj.2011.11.1841] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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Bohlen CJ, Chesler AT, Sharif-Naeini R, Medzihradszky KF, Zhou S, King D, Sánchez EE, Burlingame AL, Basbaum AI, Julius D. A heteromeric Texas coral snake toxin targets acid-sensing ion channels to produce pain. Nature 2011; 479:410-4. [PMID: 22094702 PMCID: PMC3226747 DOI: 10.1038/nature10607] [Citation(s) in RCA: 254] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2011] [Accepted: 10/15/2011] [Indexed: 12/20/2022]
Abstract
Natural products that elicit discomfort or pain represent invaluable tools for probing molecular mechanisms underlying pain sensation1. Plant-derived irritants have predominated in this regard, but animal venoms have also evolved to avert predators by targeting neurons and receptors whose activation produces noxious sensations2-6. As such, venoms provide a rich and varied source of small molecule and protein pharmacophores7,8 that can be exploited to characterize and manipulate key components of the pain-signaling pathway. With this in mind, we carried out an unbiased in vitro screen to identify snake venoms capable of activating somatosensory neurons. Venom from the Texas coral snake (Micrurus tener tener), whose bite produces intense and unremitting pain9, excited a large cohort of sensory neurons. The purified active species (MitTx) consists of a heteromeric complex between Kunitz- and phospholipase A2-like proteins that together function as a potent, persistent, and selective agonist for acid-sensing ion channels (ASICs), showing equal or greater efficacy when compared with acidic pH. MitTx is highly selective for the ASIC1 subtype at neutral pH; under more acidic conditions (pH < 6.5), MitTx massively potentiates (>100-fold) proton-evoked activation of ASIC2a channels. These observations raise the possibility that ASIC channels function as coincidence detectors for extracellular protons and other, as yet unidentified, endogenous factors. Purified MitTx elicits robust pain-related behavior in mice via activation of ASIC1 channels on capsaicin-sensitive nerve fibers. These findings reveal a mechanism whereby snake venoms produce pain, and highlight an unexpected contribution of ASIC1 channels to nociception.
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Affiliation(s)
- Christopher J Bohlen
- Department of Physiology, University of California, San Francisco, California 94158-2517, USA
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Bráz JM, Ackerman L, Basbaum AI. Sciatic nerve transection triggers release and intercellular transfer of a genetically expressed macromolecular tracer in dorsal root ganglia. J Comp Neurol 2011; 519:2648-57. [PMID: 21484801 DOI: 10.1002/cne.22645] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
We recently developed a genetic transneuronal tracing approach that allows for the study of circuits that are altered by nerve injury. We generated transgenic (ZW-X) mice in which expression of a transneuronal tracer, wheat germ agglutinin (WGA), is induced in primary sensory neurons, but only after transection of their peripheral axon. By following the transneuronal transport of the tracer into the central nervous system (CNS) we can label the circuits that are engaged by the WGA-expressing damaged neurons. Here we used the ZW-X mouse line to analyze dorsal root ganglia (DRG) for intraganglionic connections between injured sensory neurons and their neighboring "intact" neurons. Because neuropeptide Y (NPY) expression is strongly induced in DRG neurons after peripheral axotomy, we crossed the ZW-X mouse line with a mouse that expresses Cre recombinase under the influence of the NPY promoter. As expected, sciatic nerve transection triggered WGA expression in NPY-positive DRG neurons, most of which are of large diameter. As expected, double labeling for ATF-3, a marker of cell bodies with damaged axons, showed that the tracer predominated in injured (i.e., axotomized) neurons. However, we also found the WGA tracer in DRG cell bodies of uninjured sensory neurons. Importantly, in the absence of nerve injury there was no intraganglionic transfer of WGA. Our results demonstrate that intraganglionic, cell-to-cell communication, via transfer of large molecules, occurs between the cell bodies of injured and neighboring noninjured primary afferent neurons.
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Affiliation(s)
- João M Bráz
- Department of Anatomy, University of California San Francisco, San Francisco, California 94158, USA.
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Abstract
Chronic pain is estimated to be the third most prevalent health problem in the world. Although scientists have made great strides in our understanding of the molecular mechanisms through which chronic pain develops, this knowledge has not been translated into new therapies. In this issue of Science Translational Medicine, Wang and colleagues report on the development of a selective antagonist of type 1 adenylate cyclase (AC1), which is induced in subsets of neurons in the central nervous system during the development of neuropathic pain. Blockade of AC1 significantly alleviates the mechanical hypersensitivity that occurs in a mouse model of neuropathic pain without affecting acute pain responsiveness or cognitive and motor function. These features make AC1 a potential therapeutic target for the treatment of neuropathic pain.
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Affiliation(s)
- Reza Sharif-Naeini
- Department of Anatomy, University of California, San Francisco, San Francisco, CA 94158, USA
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Abstract
Hypersensitivity to thermal and mechanical stimuli can occur in painful pulpitis. To explore the neuro-anatomical basis of heat and mechanical sensitivity, we evaluated expression of TRPV1 (heat) and TRPV2 (heat/mechanical) channels in the cell bodies and terminal arborizations of neurons that innervate the dental pulp (DP) and periodontal tissues (PDL). We report that ~50% of trigeminal ganglion (TG) neurons retrogradely labeled from the DP express TRPV2, and this was significantly greater than the general expression of this channel in the TG (15%) and slightly more than what is expressed in the PDL by retrograde labeling (40%). The TRPV1 receptor, however, was less prevalent in neurons innervating the DP than their general expression in the TG (17% vs. 26%) and was more extensively expressed in neurons innervating the PDL (26%). Co-labeling studies showed that 70% of neurons that innervate the DP are myelinated. Approximately 1/3 of the retrogradely labeled neurons from the DP were calcitonin-gene-related-peptide-positive (peptide-expressing), but very few expressed the IB4 marker of non-peptidergic unmyelinated afferents. These findings suggest that the DP has a unique neurochemical innervation with regard to TRP receptor expression, which has significant implications for the mechanisms contributing to odontogenic pain and management strategies.
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Affiliation(s)
- J L Gibbs
- Department of Preventive and Restorative Dental Sciences, University of California San Francisco, CA 94158, USA.
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Bates EA, Nikai T, Brennan KC, Fu YH, Charles AC, Basbaum AI, Ptácek LJ, Ahn AH. Sumatriptan alleviates nitroglycerin-induced mechanical and thermal allodynia in mice. Cephalalgia 2011; 30:170-8. [PMID: 19489890 DOI: 10.1111/j.1468-2982.2009.01864.x] [Citation(s) in RCA: 173] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The association between the clinical use of nitroglycerin (NTG) and headache has led to the examination of NTG as a model trigger for migraine and related headache disorders, both in humans and laboratory animals. In this study in mice, we hypothesized that NTG could trigger behavioural and physiological responses that resemble a common manifestation of migraine in humans. We report that animals exhibit a dose-dependent and prolonged NTG-induced thermal and mechanical allodynia, starting 30-60 min after intraperitoneal injection of NTG at 5-10 mg/kg. NTG administration also induced Fos expression, an anatomical marker of neuronal activity in neurons of the trigeminal nucleus caudalis and cervical spinal cord dorsal horn, suggesting that enhanced nociceptive processing within the spinal cord contributes to the increased nociceptive behaviour. Moreover, sumatriptan, a drug with relative specificity for migraine, alleviated the NTG-induced allodynia. We also tested whether NTG reduces the threshold for cortical spreading depression (CSD), an event considered to be the physiological substrate of the migraine aura. We found that the threshold of CSD was unaffected by NTG, suggesting that NTG stimulates migraine mechanisms that are independent of the regulation of cortical excitability.
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Affiliation(s)
- E A Bates
- Department of Neurology, University of California, San Francisco, CA 94158, USA
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Abstract
Olfactory ensheathing glia (OEG) are distinct from other glia in their developmental origin, presence in both the peripheral and central nervous systems, and highly restricted location. OEG are present only in the olfactory lamina propria, olfactory nerve, and the outer two layers of the olfactory bulb, where they envelop bundles of olfactory sensory neuron axons in a manner distinct from myelination. Because of their unique properties and their association with the continually generated olfactory sensory neurons, OEG have attracted interest for their potential capacity to support axonal regeneration, for example, after spinal cord injury. However, study of the properties and function of OEG has been hampered by a paucity of neurochemical markers with which to identify and distinguish them definitively from other types of glia. Here we provide evidence through anatomical colocalization studies that OEG express the water channel aquaporin 1 (AQP1), both in vivo and in vitro. We propose that AQP1 expression represents an important distinguishing characteristic of OEG, which may impart unique function to these glia.
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Affiliation(s)
- Shannon D Shields
- Department of Anatomy and Physiology, WM Keck Foundation Center for Integrative Neuroscience, University of California San Francisco, San Francisco, California 94158, USA
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Affiliation(s)
- Jeffrey S Mogil
- Department of Psychology, McGill University, 1205 Dr. Penfield Ave., Montreal, QC, Canada H3A 1B1 Department of Anatomy and W.M. Keck Foundation Center for Integrative Neuroscience, University of California, San Francisco, CA, USA
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