1
|
Hawker P, Zhang L, Liu L. Mas-related G protein-coupled receptors in gastrointestinal dysfunction and inflammatory bowel disease: A review. Br J Pharmacol 2024; 181:2197-2211. [PMID: 36787888 DOI: 10.1111/bph.16059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Revised: 12/25/2022] [Accepted: 02/04/2023] [Indexed: 02/16/2023] Open
Abstract
Inflammatory bowel disease (IBD) is a chronic debilitating condition, hallmarked by persistent inflammation of the gastrointestinal tract. Despite recent advances in clinical treatments, the aetiology of IBD is unknown, and a large proportion of patients are refractory to pharmacotherapy. Understanding IBD immunopathogenesis is crucial to discern the cause of IBD and optimise treatments. Mas-related G protein-coupled receptors (Mrgprs) are a family of approximately 50 G protein-coupled receptors that were first identified over 20 years ago. Originally known for their expression in skin nociceptors and their role in transmitting the sensation of itch in the periphery, new reports have described the presence of Mrgprs in the gastrointestinal tract. In this review, we consider the impact of these findings and assess the evidence that suggests that Mrgprs may be involved in the disrupted homeostatic processes that contribute to gastrointestinal disorders and IBD. LINKED ARTICLES: This article is part of a themed issue Therapeutic Targeting of G Protein-Coupled Receptors: hot topics from the Australasian Society of Clinical and Experimental Pharmacologists and Toxicologists 2021 Virtual Annual Scientific Meeting. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v181.14/issuetoc.
Collapse
Affiliation(s)
- Patrick Hawker
- School of Medical Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - Li Zhang
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - Lu Liu
- School of Medical Sciences, University of New South Wales, Sydney, New South Wales, Australia
| |
Collapse
|
2
|
Bhuiyan SA, Xu M, Yang L, Semizoglou E, Bhatia P, Pantaleo KI, Tochitsky I, Jain A, Erdogan B, Blair S, Cat V, Mwirigi JM, Sankaranarayanan I, Tavares-Ferreira D, Green U, McIlvried LA, Copits BA, Bertels Z, Del Rosario JS, Widman AJ, Slivicki RA, Yi J, Sharif-Naeini R, Woolf CJ, Lennerz JK, Whited JL, Price TJ, Robert W Gereau Iv, Renthal W. Harmonized cross-species cell atlases of trigeminal and dorsal root ganglia. SCIENCE ADVANCES 2024; 10:eadj9173. [PMID: 38905344 DOI: 10.1126/sciadv.adj9173] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Accepted: 05/16/2024] [Indexed: 06/23/2024]
Abstract
Sensory neurons in the dorsal root ganglion (DRG) and trigeminal ganglion (TG) are specialized to detect and transduce diverse environmental stimuli to the central nervous system. Single-cell RNA sequencing has provided insights into the diversity of sensory ganglia cell types in rodents, nonhuman primates, and humans, but it remains difficult to compare cell types across studies and species. We thus constructed harmonized atlases of the DRG and TG that describe and facilitate comparison of 18 neuronal and 11 non-neuronal cell types across six species and 31 datasets. We then performed single-cell/nucleus RNA sequencing of DRG from both human and the highly regenerative axolotl and found that the harmonized atlas also improves cell type annotation, particularly of sparse neuronal subtypes. We observed that the transcriptomes of sensory neuron subtypes are broadly similar across vertebrates, but the expression of functionally important neuropeptides and channels can vary notably. The resources presented here can guide future studies in comparative transcriptomics, simplify cell-type nomenclature differences across studies, and help prioritize targets for future analgesic development.
Collapse
Affiliation(s)
- Shamsuddin A Bhuiyan
- Department of Neurology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Mengyi Xu
- Department of Neurology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
- Alan Edwards Center for Research on Pain and Department of Physiology, McGill University, Montreal, QC, H3G 1Y6, Canada
| | - Lite Yang
- Department of Neurology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
- Washington University Pain Center and Department of Anesthesiology, Washington University School of Medicine, St Louis, MO 63110, USA
| | - Evangelia Semizoglou
- Department of Neurology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Parth Bhatia
- Department of Neurology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Katerina I Pantaleo
- Department of Neurology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Ivan Tochitsky
- F.M. Kirby Neurobiology Center and Department of Neurobiology, Boston Children's Hospital and Harvard Medical School, 3 Blackfan Cir., Boston, MA 02115, USA
| | - Aakanksha Jain
- F.M. Kirby Neurobiology Center and Department of Neurobiology, Boston Children's Hospital and Harvard Medical School, 3 Blackfan Cir., Boston, MA 02115, USA
| | - Burcu Erdogan
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA, 02138, USA
| | - Steven Blair
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA, 02138, USA
| | - Victor Cat
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA, 02138, USA
| | - Juliet M Mwirigi
- Department of Neuroscience and Center for Advanced Pain Studies, University of Texas at Dallas, 800 W Campbell Rd, Richardson, TX, 75080, USA
| | - Ishwarya Sankaranarayanan
- Department of Neuroscience and Center for Advanced Pain Studies, University of Texas at Dallas, 800 W Campbell Rd, Richardson, TX, 75080, USA
| | - Diana Tavares-Ferreira
- Department of Neuroscience and Center for Advanced Pain Studies, University of Texas at Dallas, 800 W Campbell Rd, Richardson, TX, 75080, USA
| | - Ursula Green
- Department of Pathology, Center for Integrated Diagnostics, Massachussetts General Hospital and Havard Medical School, Boston, MA 02114, USA
| | - Lisa A McIlvried
- Washington University Pain Center and Department of Anesthesiology, Washington University School of Medicine, St Louis, MO 63110, USA
| | - Bryan A Copits
- Washington University Pain Center and Department of Anesthesiology, Washington University School of Medicine, St Louis, MO 63110, USA
| | - Zachariah Bertels
- Washington University Pain Center and Department of Anesthesiology, Washington University School of Medicine, St Louis, MO 63110, USA
| | - John S Del Rosario
- Washington University Pain Center and Department of Anesthesiology, Washington University School of Medicine, St Louis, MO 63110, USA
| | - Allie J Widman
- Washington University Pain Center and Department of Anesthesiology, Washington University School of Medicine, St Louis, MO 63110, USA
| | - Richard A Slivicki
- Washington University Pain Center and Department of Anesthesiology, Washington University School of Medicine, St Louis, MO 63110, USA
| | - Jiwon Yi
- Washington University Pain Center and Department of Anesthesiology, Washington University School of Medicine, St Louis, MO 63110, USA
| | - Reza Sharif-Naeini
- Alan Edwards Center for Research on Pain and Department of Physiology, McGill University, Montreal, QC, H3G 1Y6, Canada
| | - Clifford J Woolf
- F.M. Kirby Neurobiology Center and Department of Neurobiology, Boston Children's Hospital and Harvard Medical School, 3 Blackfan Cir., Boston, MA 02115, USA
| | - Jochen K Lennerz
- Department of Pathology, Center for Integrated Diagnostics, Massachussetts General Hospital and Havard Medical School, Boston, MA 02114, USA
| | - Jessica L Whited
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA, 02138, USA
| | - Theodore J Price
- Department of Neuroscience and Center for Advanced Pain Studies, University of Texas at Dallas, 800 W Campbell Rd, Richardson, TX, 75080, USA
| | - Robert W Gereau Iv
- Washington University Pain Center and Department of Anesthesiology, Washington University School of Medicine, St Louis, MO 63110, USA
| | - William Renthal
- Department of Neurology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| |
Collapse
|
3
|
George DS, Jayaraj ND, Pacifico P, Ren D, Sriram N, Miller RE, Malfait AM, Miller RJ, Menichella DM. The Mas-related G protein-coupled receptor d (Mrgprd) mediates pain hypersensitivity in painful diabetic neuropathy. Pain 2024; 165:1154-1168. [PMID: 38147415 PMCID: PMC11017747 DOI: 10.1097/j.pain.0000000000003120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Revised: 08/22/2023] [Accepted: 08/22/2023] [Indexed: 12/28/2023]
Abstract
ABSTRACT Painful diabetic neuropathy (PDN) is one of the most common and intractable complications of diabetes. Painful diabetic neuropathy is characterized by neuropathic pain accompanied by dorsal root ganglion (DRG) nociceptor hyperexcitability, axonal degeneration, and changes in cutaneous innervation. However, the complete molecular profile underlying the hyperexcitable cellular phenotype of DRG nociceptors in PDN has not been elucidated. This gap in our knowledge is a critical barrier to developing effective, mechanism-based, and disease-modifying therapeutic approaches that are urgently needed to relieve the symptoms of PDN. Using single-cell RNA sequencing of DRGs, we demonstrated an increased expression of the Mas-related G protein-coupled receptor d (Mrgprd) in a subpopulation of DRG neurons in the well-established high-fat diet (HFD) mouse model of PDN. Importantly, limiting Mrgprd signaling reversed mechanical allodynia in the HFD mouse model of PDN. Furthermore, in vivo calcium imaging allowed us to demonstrate that activation of Mrgprd-positive cutaneous afferents that persist in diabetic mice skin resulted in an increased intracellular calcium influx into DRG nociceptors that we assess in vivo as a readout of nociceptors hyperexcitability. Taken together, our data highlight a key role of Mrgprd-mediated DRG neuron excitability in the generation and maintenance of neuropathic pain in a mouse model of PDN. Hence, we propose Mrgprd as a promising and accessible target for developing effective therapeutics currently unavailable for treating neuropathic pain in PDN.
Collapse
Affiliation(s)
| | | | | | - Dongjun Ren
- Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
| | | | - Rachel E. Miller
- Department of Internal Medicine, Rush Medical College, Chicago, IL, United States
| | - Anne-Marie Malfait
- Department of Internal Medicine, Rush Medical College, Chicago, IL, United States
| | - Richard J. Miller
- Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
| | - Daniela Maria Menichella
- Departments of Neurology and
- Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
| |
Collapse
|
4
|
Qi L, Iskols M, Shi D, Reddy P, Walker C, Lezgiyeva K, Voisin T, Pawlak M, Kuchroo VK, Chiu IM, Ginty DD, Sharma N. A mouse DRG genetic toolkit reveals morphological and physiological diversity of somatosensory neuron subtypes. Cell 2024; 187:1508-1526.e16. [PMID: 38442711 PMCID: PMC10947841 DOI: 10.1016/j.cell.2024.02.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2023] [Revised: 11/12/2023] [Accepted: 02/05/2024] [Indexed: 03/07/2024]
Abstract
Dorsal root ganglia (DRG) somatosensory neurons detect mechanical, thermal, and chemical stimuli acting on the body. Achieving a holistic view of how different DRG neuron subtypes relay neural signals from the periphery to the CNS has been challenging with existing tools. Here, we develop and curate a mouse genetic toolkit that allows for interrogating the properties and functions of distinct cutaneous targeting DRG neuron subtypes. These tools have enabled a broad morphological analysis, which revealed distinct cutaneous axon arborization areas and branching patterns of the transcriptionally distinct DRG neuron subtypes. Moreover, in vivo physiological analysis revealed that each subtype has a distinct threshold and range of responses to mechanical and/or thermal stimuli. These findings support a model in which morphologically and physiologically distinct cutaneous DRG sensory neuron subtypes tile mechanical and thermal stimulus space to collectively encode a wide range of natural stimuli.
Collapse
Affiliation(s)
- Lijun Qi
- Department of Neurobiology, Howard Hughes Medical Institute, Harvard Medical School, 220 Longwood Avenue, Boston, MA 02115, USA
| | - Michael Iskols
- Department of Neurobiology, Howard Hughes Medical Institute, Harvard Medical School, 220 Longwood Avenue, Boston, MA 02115, USA
| | - David Shi
- Department of Molecular Pharmacology and Therapeutics, Vagelos College of Physicians and Surgeons, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Pranav Reddy
- Department of Molecular Pharmacology and Therapeutics, Vagelos College of Physicians and Surgeons, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Christopher Walker
- Department of Molecular Pharmacology and Therapeutics, Vagelos College of Physicians and Surgeons, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Karina Lezgiyeva
- Department of Neurobiology, Howard Hughes Medical Institute, Harvard Medical School, 220 Longwood Avenue, Boston, MA 02115, USA
| | - Tiphaine Voisin
- Department of Immunology, Harvard Medical School, Boston, MA 02115, USA
| | - Mathias Pawlak
- Gene Lay Institute of Immunology and Inflammation, Brigham and Women's Hospital, Mass General Hospital, and Harvard Medical School, Boston, MA 02115, USA
| | - Vijay K Kuchroo
- Gene Lay Institute of Immunology and Inflammation, Brigham and Women's Hospital, Mass General Hospital, and Harvard Medical School, Boston, MA 02115, USA
| | - Isaac M Chiu
- Department of Immunology, Harvard Medical School, Boston, MA 02115, USA
| | - David D Ginty
- Department of Neurobiology, Howard Hughes Medical Institute, Harvard Medical School, 220 Longwood Avenue, Boston, MA 02115, USA.
| | - Nikhil Sharma
- Department of Neurobiology, Howard Hughes Medical Institute, Harvard Medical School, 220 Longwood Avenue, Boston, MA 02115, USA; Department of Molecular Pharmacology and Therapeutics, Vagelos College of Physicians and Surgeons, Columbia University Irving Medical Center, New York, NY 10032, USA.
| |
Collapse
|
5
|
Majumdar S, Chiu YT, Pickett JE, Roth BL. Illuminating the understudied GPCR-ome. Drug Discov Today 2024; 29:103848. [PMID: 38052317 DOI: 10.1016/j.drudis.2023.103848] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Revised: 11/17/2023] [Accepted: 11/28/2023] [Indexed: 12/07/2023]
Abstract
G-protein-coupled receptors (GPCRs) are the target of >30% of approved drugs. Despite their popularity, many of the >800 human GPCRs remain understudied. The Illuminating the Druggable Genome (IDG) project has generated many tools leading to important insights into the function and druggability of these so-called 'dark' receptors. These tools include assays, such as PRESTO-TANGO and TRUPATH, billions of small molecules made available via the ZINC virtual library, solved orphan GPCR structures, GPCR knock-in mice, and more. Together, these tools are illuminating the remaining 'dark' GPCRs.
Collapse
Affiliation(s)
- Sreeparna Majumdar
- Department of Pharmacology, UNC Chapel Hill School of Medicine, Chapel Hill, NC 27599, USA
| | - Yi-Ting Chiu
- Department of Pharmacology, UNC Chapel Hill School of Medicine, Chapel Hill, NC 27599, USA
| | - Julie E Pickett
- Department of Pharmacology, UNC Chapel Hill School of Medicine, Chapel Hill, NC 27599, USA
| | - Bryan L Roth
- Department of Pharmacology, UNC Chapel Hill School of Medicine, Chapel Hill, NC 27599, USA.
| |
Collapse
|
6
|
Erbacher C, Britz S, Dinkel P, Klein T, Sauer M, Stigloher C, Üçeyler N. Interaction of human keratinocytes and nerve fiber terminals at the neuro-cutaneous unit. eLife 2024; 13:e77761. [PMID: 38225894 PMCID: PMC10791129 DOI: 10.7554/elife.77761] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Accepted: 12/19/2023] [Indexed: 01/17/2024] Open
Abstract
Traditionally, peripheral sensory neurons are assumed as the exclusive transducers of external stimuli. Current research moves epidermal keratinocytes into focus as sensors and transmitters of nociceptive and non-nociceptive sensations, tightly interacting with intraepidermal nerve fibers at the neuro-cutaneous unit. In animal models, epidermal cells establish close contacts and ensheath sensory neurites. However, ultrastructural morphological and mechanistic data examining the human keratinocyte-nerve fiber interface are sparse. We investigated this exact interface in human skin applying super-resolution array tomography, expansion microscopy, and structured illumination microscopy. We show keratinocyte ensheathment of afferents and adjacent connexin 43 contacts in native skin and have applied a pipeline based on expansion microscopy to quantify these parameter in skin sections of healthy participants versus patients with small fiber neuropathy. We further derived a fully human co-culture system, visualizing ensheathment and connexin 43 plaques in vitro. Unraveling human intraepidermal nerve fiber ensheathment and potential interaction sites advances research at the neuro-cutaneous unit. These findings are crucial on the way to decipher the mechanisms of cutaneous nociception.
Collapse
Affiliation(s)
| | - Sebastian Britz
- Imaging Core Facility, Biocenter, University of WürzburgWürzburgGermany
| | - Philine Dinkel
- Department of Neurology, University Hospital of WürzburgWürzburgGermany
| | - Thomas Klein
- Department of Neurology, University Hospital of WürzburgWürzburgGermany
| | - Markus Sauer
- Department of Biotechnology and Biophysics, University of WürzburgWürzburgGermany
| | | | - Nurcan Üçeyler
- Department of Neurology, University Hospital of WürzburgWürzburgGermany
| |
Collapse
|
7
|
Fiebig A, Leibl V, Oostendorf D, Lukaschek S, Frömbgen J, Masoudi M, Kremer AE, Strupf M, Reeh P, Düll M, Namer B. Peripheral signaling pathways contributing to non-histaminergic itch in humans. J Transl Med 2023; 21:908. [PMID: 38087354 PMCID: PMC10717026 DOI: 10.1186/s12967-023-04698-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Accepted: 11/04/2023] [Indexed: 12/18/2023] Open
Abstract
BACKGROUND Chronic itch (chronic pruritus) is a major therapeutic challenge that remains poorly understood despite the extensive recent analysis of human pruriceptors. It is unclear how the peripheral nervous system differentiates the signaling of non-histaminergic itch and pain. METHODS Here we used psychophysical analysis and microneurography (single nerve fiber recordings) in healthy human volunteers to explore the distinct signaling mechanisms of itch, using the pruritogens β-alanine, BAM 8-22 and cowhage extract. RESULTS The mode of application (injection or focal application using inactivated cowhage spicules) influenced the itch/pain ratio in sensations induced by BAM 8-22 and cowhage but not β-alanine. We found that sensitizing pre-injections of prostaglandin E2 increased the pain component of BAM 8-22 but not the other pruritogens. A-fibers contributed only to itch induced by β-alanine. TRPV1 and TRPA1 were necessary for itch signaling induced by all three pruritogens. In single-fiber recordings, we found that BAM 8-22 and β-alanine injection activated nearly all CM-fibers (to different extents) but not CMi-fibers, whereas cowhage extract injection activated only 56% of CM-fibers but also 25% of CMi-fibers. A "slow bursting discharge pattern" was evoked in 25% of CM-fibers by β-alanine, in 35% by BAM 8-22, but in only 10% by cowhage extract. CONCLUSION Our results indicate that no labeled line exists for these pruritogens in humans. A combination of different mechanisms, specific for each pruritogen, leads to itching sensations rather than pain. Notably, non-receptor-based mechanisms such as spatial contrast or discharge pattern coding seem to be important processes. These findings will facilitate the discovery of therapeutic targets for chronic pruritus, which are unlikely to be treated effectively by single receptor blockade.
Collapse
Affiliation(s)
- Andrea Fiebig
- Research Group Neuroscience, Interdisciplinary Centre for Clinical Research, Faculty of Medicine, RWTH Aachen University, Aachen, Germany
- Institute of Neurophysiology, Uniklinik RWTH Aachen University, Aachen, Germany
| | - Victoria Leibl
- Institute of Physiology and Pathophysiology, University of Erlangen-Nürnberg, 91054, Erlangen, Germany
| | - David Oostendorf
- Institute of Physiology and Pathophysiology, University of Erlangen-Nürnberg, 91054, Erlangen, Germany
| | - Saskia Lukaschek
- Research Group Neuroscience, Interdisciplinary Centre for Clinical Research, Faculty of Medicine, RWTH Aachen University, Aachen, Germany
- Institute of Neurophysiology, Uniklinik RWTH Aachen University, Aachen, Germany
| | - Jens Frömbgen
- Research Group Neuroscience, Interdisciplinary Centre for Clinical Research, Faculty of Medicine, RWTH Aachen University, Aachen, Germany
- Institute of Neurophysiology, Uniklinik RWTH Aachen University, Aachen, Germany
| | - Maral Masoudi
- Institute of Physiology and Pathophysiology, University of Erlangen-Nürnberg, 91054, Erlangen, Germany
| | - Andreas E Kremer
- Department of Gastroenterology and Hepatology, University Hospital Zürich, University of Zürich, Zurich, Switzerland
| | - Marion Strupf
- Institute of Physiology and Pathophysiology, University of Erlangen-Nürnberg, 91054, Erlangen, Germany
| | - Peter Reeh
- Institute of Physiology and Pathophysiology, University of Erlangen-Nürnberg, 91054, Erlangen, Germany
| | - Miriam Düll
- Institute of Physiology and Pathophysiology, University of Erlangen-Nürnberg, 91054, Erlangen, Germany
- Department of Medicine 1, University Hospital Erlangen and Friedrich-Alexander-University Erlangen-Nürnberg, Erlangen, Germany
| | - Barbara Namer
- Research Group Neuroscience, Interdisciplinary Centre for Clinical Research, Faculty of Medicine, RWTH Aachen University, Aachen, Germany.
- Institute of Neurophysiology, Uniklinik RWTH Aachen University, Aachen, Germany.
- Institute of Physiology and Pathophysiology, University of Erlangen-Nürnberg, 91054, Erlangen, Germany.
| |
Collapse
|
8
|
Che T, Roth BL. Molecular basis of opioid receptor signaling. Cell 2023; 186:5203-5219. [PMID: 37995655 PMCID: PMC10710086 DOI: 10.1016/j.cell.2023.10.029] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Revised: 10/13/2023] [Accepted: 10/27/2023] [Indexed: 11/25/2023]
Abstract
Opioids are used for pain management despite the side effects that contribute to the opioid crisis. The pursuit of non-addictive opioid analgesics remains unattained due to the unresolved intricacies of opioid actions, receptor signaling cascades, and neuronal plasticity. Advancements in structural, molecular, and computational tools illuminate the dynamic interplay between opioids and opioid receptors, as well as the molecular determinants of signaling pathways, which are potentially interlinked with pharmacological responses. Here, we review the molecular basis of opioid receptor signaling with a focus on the structures of opioid receptors bound to endogenous peptides or pharmacological agents. These insights unveil specific interactions that dictate ligand selectivity and likely their distinctive pharmacological profiles. Biochemical analysis further unveils molecular features governing opioid receptor signaling. Simultaneously, the synergy between computational biology and medicinal chemistry continues to expedite the discovery of novel chemotypes with the promise of yielding more efficacious and safer opioid compounds.
Collapse
Affiliation(s)
- Tao Che
- Department of Anesthesiology, Washington University School of Medicine, Saint Louis, MO 63110, USA; Center for Clinical Pharmacology, University of Health Sciences & Pharmacy and Washington University School of Medicine, Saint Louis, MO 63110, USA.
| | - Bryan L Roth
- Department of Pharmacology, University of North Carolina Chapel Hill School of Medicine, Chapel Hill 27599, NC, USA.
| |
Collapse
|
9
|
Tram M, Ibrahim T, Hovhannisyan A, Akopian A, Ruparel S. Lingual innervation in male and female marmosets. NEUROBIOLOGY OF PAIN (CAMBRIDGE, MASS.) 2023; 14:100134. [PMID: 38099285 PMCID: PMC10719518 DOI: 10.1016/j.ynpai.2023.100134] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 05/26/2023] [Accepted: 05/26/2023] [Indexed: 12/17/2023]
Abstract
Several gaps in knowledge exists in our understanding of orofacial pain. Some of these include type of peripheral sensory innervation in specific tissues, differences in innervation between sexes and validation of rodent studies in higher order species. The current study addresses these gaps by validating mouse studies for sensory innervation of tongue tissue in non-human primates as well as assesses sex-specific differences. Tongue and trigeminal ganglia were collected from naïve male and female marmosets and tested for nerve fibers using specific markers by immunohistochemistry and number of fibers quantified. We also tested whether specific subgroups of nerve fibers belonged to myelinating or non-myelinating axons. We observed that similar to findings in mice, marmoset tongue was innervated with nerve filaments expressing nociceptor markers like CGRP and TRPV1 as well as non-nociceptor markers like TrkB, parvalbumin (PV) and tyrosine hydroxylase (TH). Furthermore, we found that while portion of TrkB and PV may be sensory fibers, TH-positive fibers were primarily sympathetic nerve fibers. Moreover, number of CGRP, TrkB and TH-positive nerve fibers were similar in both sexes. However, we observed a higher proportion of myelinated TRPV1 positive fibers in females than in males as well as increased number of PV + fibers in females. Taken together, the study for the first time characterizes sensory innervation in non-human primates as well as evaluates sex-differences in innervation of tongue tissue, thereby laying the foundation for future orofacial pain research with new world smaller NHPs like the common marmoset.
Collapse
Affiliation(s)
- Meilinn Tram
- Department of Endodontics, School of Dentistry, University of Texas Health San Antonio, USA
| | - Tarek Ibrahim
- Department of Endodontics, School of Dentistry, University of Texas Health San Antonio, USA
| | - Anahit Hovhannisyan
- Department of Endodontics, School of Dentistry, University of Texas Health San Antonio, USA
| | - Armen Akopian
- Department of Endodontics, School of Dentistry, University of Texas Health San Antonio, USA
| | - Shivani Ruparel
- Department of Endodontics, School of Dentistry, University of Texas Health San Antonio, USA
| |
Collapse
|
10
|
Schmitz GP, Roth BL. G protein-coupled receptors as targets for transformative neuropsychiatric therapeutics. Am J Physiol Cell Physiol 2023; 325:C17-C28. [PMID: 37067459 PMCID: PMC10281788 DOI: 10.1152/ajpcell.00397.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 03/28/2023] [Accepted: 04/06/2023] [Indexed: 04/18/2023]
Abstract
G protein-coupled receptors (GPCRs) constitute the largest family of druggable genes in the human genome. Even though perhaps 30% of approved medications target GPCRs, they interact with only a small number of them. Here, we consider whether there might be new opportunities for transformative therapeutics for neuropsychiatric disorders by specifically targeting both known and understudied GPCRs. Using psychedelic drugs that target serotonin receptors as an example, we show how recent insights into the structure, function, signaling, and cell biology of these receptors have led to potentially novel therapeutics. We next focus on the possibility that nonpsychedelic 5-HT2A receptor agonists might prove to be safe and rapidly acting antidepressants. Finally, we examine understudied and orphan GPCRs using the MRGPR family of receptors as an example.
Collapse
Affiliation(s)
- Gavin P Schmitz
- Department of Pharmacology, UNC Chapel Hill Medical School, Chapel Hill, North Carolina, United States
| | - Bryan L Roth
- Department of Pharmacology, UNC Chapel Hill Medical School, Chapel Hill, North Carolina, United States
| |
Collapse
|
11
|
Kupari J, Ernfors P. Molecular taxonomy of nociceptors and pruriceptors. Pain 2023; 164:1245-1257. [PMID: 36718807 PMCID: PMC10184562 DOI: 10.1097/j.pain.0000000000002831] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 11/10/2022] [Accepted: 11/21/2022] [Indexed: 02/01/2023]
Affiliation(s)
- Jussi Kupari
- Division of Molecular Neurobiology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Patrik Ernfors
- Division of Molecular Neurobiology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| |
Collapse
|
12
|
Qi L, Iskols M, Shi D, Reddy P, Walker C, Lezgiyeva K, Voisin T, Pawlak M, Kuchroo VK, Chiu I, Ginty DD, Sharma N. A DRG genetic toolkit reveals molecular, morphological, and functional diversity of somatosensory neuron subtypes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.22.537932. [PMID: 37131664 PMCID: PMC10153270 DOI: 10.1101/2023.04.22.537932] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Mechanical and thermal stimuli acting on the skin are detected by morphologically and physiologically distinct sensory neurons of the dorsal root ganglia (DRG). Achieving a holistic view of how this diverse neuronal population relays sensory information from the skin to the central nervous system (CNS) has been challenging with existing tools. Here, we used transcriptomic datasets of the mouse DRG to guide development and curation of a genetic toolkit to interrogate transcriptionally defined DRG neuron subtypes. Morphological analysis revealed unique cutaneous axon arborization areas and branching patterns of each subtype. Physiological analysis showed that subtypes exhibit distinct thresholds and ranges of responses to mechanical and/or thermal stimuli. The somatosensory neuron toolbox thus enables comprehensive phenotyping of most principal sensory neuron subtypes. Moreover, our findings support a population coding scheme in which the activation thresholds of morphologically and physiologically distinct cutaneous DRG neuron subtypes tile multiple dimensions of stimulus space.
Collapse
Affiliation(s)
- Lijun Qi
- Department of Neurobiology, Howard Hughes Medical Institute, Harvard Medical School, 220 Longwood Avenue, Boston, MA 02115
| | - Michael Iskols
- Department of Neurobiology, Howard Hughes Medical Institute, Harvard Medical School, 220 Longwood Avenue, Boston, MA 02115
| | - David Shi
- Department of Molecular Pharmacology and Therapeutics, Department of Systems Biology, Columbia University, New York, NY
| | - Pranav Reddy
- Department of Molecular Pharmacology and Therapeutics, Department of Systems Biology, Columbia University, New York, NY
| | - Christopher Walker
- Department of Molecular Pharmacology and Therapeutics, Department of Systems Biology, Columbia University, New York, NY
| | - Karina Lezgiyeva
- Department of Neurobiology, Howard Hughes Medical Institute, Harvard Medical School, 220 Longwood Avenue, Boston, MA 02115
| | - Tiphaine Voisin
- Department of Immunology, Harvard Medical School, Boston, MA 02115
| | - Mathias Pawlak
- Evergrande Center for Immunologic Diseases, Harvard Medical School and Brigham and Women's Hospital, Boston, MA 02115, USA
| | - Vijay K. Kuchroo
- Evergrande Center for Immunologic Diseases, Harvard Medical School and Brigham and Women's Hospital, Boston, MA 02115, USA
| | - Isaac Chiu
- Department of Immunology, Harvard Medical School, Boston, MA 02115
| | - David D. Ginty
- Department of Neurobiology, Howard Hughes Medical Institute, Harvard Medical School, 220 Longwood Avenue, Boston, MA 02115
| | - Nikhil Sharma
- Department of Neurobiology, Howard Hughes Medical Institute, Harvard Medical School, 220 Longwood Avenue, Boston, MA 02115
- Department of Molecular Pharmacology and Therapeutics, Department of Systems Biology, Columbia University, New York, NY
| |
Collapse
|
13
|
Liu Y, Cao C, Huang XP, Gumpper RH, Rachman MM, Shih SL, Krumm BE, Zhang S, Shoichet BK, Fay JF, Roth BL. Ligand recognition and allosteric modulation of the human MRGPRX1 receptor. Nat Chem Biol 2023; 19:416-422. [PMID: 36302898 DOI: 10.1038/s41589-022-01173-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Accepted: 09/13/2022] [Indexed: 11/09/2022]
Abstract
The human MAS-related G protein-coupled receptor X1 (MRGPRX1) is preferentially expressed in the small-diameter primary sensory neurons and involved in the mediation of nociception and pruritus. Central activation of MRGPRX1 by the endogenous opioid peptide fragment BAM8-22 and its positive allosteric modulator ML382 has been shown to effectively inhibit persistent pain, making MRGPRX1 a promising target for non-opioid pain treatment. However, the activation mechanism of MRGPRX1 is still largely unknown. Here we report three high-resolution cryogenic electron microscopy structures of MRGPRX1-Gαq in complex with BAM8-22 alone, with BAM8-22 and ML382 simultaneously as well as with a synthetic agonist compound-16. These structures reveal the agonist binding mode for MRGPRX1 and illuminate the structural requirements for positive allosteric modulation. Collectively, our findings provide a molecular understanding of the activation and allosteric modulation of the MRGPRX1 receptor, which could facilitate the structure-based design of non-opioid pain-relieving drugs.
Collapse
Affiliation(s)
- Yongfeng Liu
- Department of Pharmacology, University of North Carolina School of Medicine, Chapel Hill, NC, USA
- National Institute of Mental Health Psychoactive Drug Screening Program, University of North Carolina School of Medicine, Chapel Hill, NC, USA
| | - Can Cao
- Department of Pharmacology, University of North Carolina School of Medicine, Chapel Hill, NC, USA
| | - Xi-Ping Huang
- Department of Pharmacology, University of North Carolina School of Medicine, Chapel Hill, NC, USA
- National Institute of Mental Health Psychoactive Drug Screening Program, University of North Carolina School of Medicine, Chapel Hill, NC, USA
| | - Ryan H Gumpper
- Department of Pharmacology, University of North Carolina School of Medicine, Chapel Hill, NC, USA
| | - Moira M Rachman
- Department of Pharmaceutical Sciences, University of California, San Francisco School of Medicine, San Francisco, CA, USA
| | - Sheng-Luen Shih
- Department of Pharmacology, University of North Carolina School of Medicine, Chapel Hill, NC, USA
- National Institute of Mental Health Psychoactive Drug Screening Program, University of North Carolina School of Medicine, Chapel Hill, NC, USA
| | - Brian E Krumm
- Department of Pharmacology, University of North Carolina School of Medicine, Chapel Hill, NC, USA
| | - Shicheng Zhang
- Department of Pharmacology, University of North Carolina School of Medicine, Chapel Hill, NC, USA
| | - Brian K Shoichet
- Department of Pharmaceutical Sciences, University of California, San Francisco School of Medicine, San Francisco, CA, USA
| | - Jonathan F Fay
- Department of Biochemistry and Biophysics, University of North Carolina School of Medicine, Chapel Hill, NC, USA.
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD, USA.
| | - Bryan L Roth
- Department of Pharmacology, University of North Carolina School of Medicine, Chapel Hill, NC, USA.
- National Institute of Mental Health Psychoactive Drug Screening Program, University of North Carolina School of Medicine, Chapel Hill, NC, USA.
- Division of Chemical Biology and Medicinal Chemistry, University of North Carolina School of Medicine, Chapel Hill, NC, USA.
| |
Collapse
|
14
|
Cao C, Roth BL. The structure, function, and pharmacology of MRGPRs. Trends Pharmacol Sci 2023; 44:237-251. [PMID: 36870785 PMCID: PMC10066734 DOI: 10.1016/j.tips.2023.02.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 02/01/2023] [Accepted: 02/09/2023] [Indexed: 03/06/2023]
Abstract
Mas-related G protein-coupled receptor (MRGPR) family members play important roles in the sensation of noxious stimuli and represent novel targets for the treatment of itch and pain. MRGPRs recognize a diversity of agonists and display complicated downstream signaling profiles, high sequence diversity across species, and many polymorphisms in humans. The recent structural advances on MRGPRs reveal unique structural features and diverse agonist recognition modes of this receptor family, which should facilitate the structure-based drug discovery at MRGPRs. In addition, the newly discovered ligands also provide valuable tools to explore the function and the therapeutic potential of MRGPRs. In this review, we discuss these progresses in our understanding of MRGPRs and highlight the challenges and potential opportunities for the future drug discovery at these receptors.
Collapse
Affiliation(s)
- Can Cao
- Department of Pharmacology, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA
| | - Bryan L Roth
- Department of Pharmacology, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA; Division of Chemical Biology and Medicinal Chemistry, Eschelman School of Pharmacy and NIMH Psychoactive Drug Screening Program, University of North Carolina, Chapel Hill, NC 27599, USA.
| |
Collapse
|
15
|
Zhou GK, Xu WJ, Lu Y, Zhou Y, Feng CZ, Zhang JT, Sun SY, Wang RM, Liu T, Wu B. Acid-sensing ion channel 3 is required for agmatine-induced histamine-independent itch in mice. Front Mol Neurosci 2023; 16:1086285. [PMID: 36937045 PMCID: PMC10016355 DOI: 10.3389/fnmol.2023.1086285] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Accepted: 02/06/2023] [Indexed: 03/05/2023] Open
Abstract
Introduction Itch is a common symptom of many skin and systemic diseases. Identifying novel endogenous itch mediators and the downstream signaling pathways involved will contribute to the development of new strategies for the treatment of chronic itch. In the present study, we adopted behavioral testing, patch clamp recording and metabonomics analysis to investigate the role of agmatine in itch and the underlying mechanism. Methods Behavioral analysis was used to evaluate the establishing of acute and chronic itch mice model, and to test the effects of different drugs or agents on mice itch behavior. Western blotting analysis was used to test the effect of agmatine on phosphorylation of ERK (p-ERK) expression in the spinal cord. Patch clamp recording was used to determine the effect agmatine on the excitability of DRG neurons and the role of ASIC3. Finally, the metabonomics analysis was performed to detect the concentration of agmatine in the affected skin under atopic dermatitis or psoriasis conditions. Results We fused a mouse model and found that an intradermal injection of agmatine (an endogenous polyamine) into the nape of the neck or cheek induced histamine-independent scratching behavior in a dose-dependent manner. In addition, the ablation of nociceptive C-fibers by resiniferatoxin (RTX) abolished agmatine-induced scratching behavior. However, agmatine-induced itch was not affected by the pharmacological inhibition of either transient receptor potential vanilloid 1 (TRPV1) or transient receptor potential ankyrin 1 (TRPA1); similar results were obtained from TRPV1-/- or TRPA1-/- mice. Furthermore, agmatine-induced itch was significantly suppressed by the administration of acid-sensing ion channel 3 (ASIC3) inhibitors, APETx2 or amiloride. Agmatine also induced the upregulation of p-ERK in the spinal cord; this effect was inhibited by amiloride. Current clamp recording showed that the acute perfusion of agmatine reduced the rheobase and increased the number of evoked action potentials in acute dissociated dorsal root ganglion (DRG) neurons while amiloride reversed agmatine-induced neuronal hyperexcitability. Finally, we identified significantly higher levels of agmatine in the affected skin of a mouse model of atopic dermatitis (AD) when compared to controls, and the scratching behavior of AD mice was significantly attenuated by blocking ASIC3. Discussion Collectively, these results provide evidence that agmatine is a novel mediator of itch and induces itch via the activation of ASIC3. Targeting neuronal ASIC3 signaling may represent a novel strategy for the treatment of itch.
Collapse
Affiliation(s)
- Guo-Kun Zhou
- Institute of Pain Medicine and Special Environmental Medicine, Nantong University, Nantong, Jiangsu, China
| | - Wen-Jing Xu
- Institute of Pain Medicine and Special Environmental Medicine, Nantong University, Nantong, Jiangsu, China
| | - Yi Lu
- Institute of Pain Medicine and Special Environmental Medicine, Nantong University, Nantong, Jiangsu, China
| | - Yan Zhou
- Jiangsu Key Laboratory of Neuropsychiatric Diseases, Institute of Neuroscience, Soochow University, Suzhou, China
| | - Chen-Zhang Feng
- State Key Laboratory of Neuroscience, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Institute of Neuroscience, Shanghai, China
| | - Jiang-Tao Zhang
- Institute of Pain Medicine and Special Environmental Medicine, Nantong University, Nantong, Jiangsu, China
| | - Shi-Yu Sun
- Institute of Pain Medicine and Special Environmental Medicine, Nantong University, Nantong, Jiangsu, China
| | - Ruo-Meng Wang
- Jiangsu Key Laboratory of Neuropsychiatric Diseases, Institute of Neuroscience, Soochow University, Suzhou, China
| | - Tong Liu
- Institute of Pain Medicine and Special Environmental Medicine, Nantong University, Nantong, Jiangsu, China
- College of Life Sciences, Yanan University, Yanan, China
- Suzhou Key Laboratory of Intelligent Medicine and Equipment, Suzhou, China
- *Correspondence: Tong Liu,
| | - Bin Wu
- Institute of Pain Medicine and Special Environmental Medicine, Nantong University, Nantong, Jiangsu, China
- Bin Wu,
| |
Collapse
|
16
|
Starobova H, Alshammari A, Winkler IG, Vetter I. The role of the neuronal microenvironment in sensory function and pain pathophysiology. J Neurochem 2022. [PMID: 36394416 DOI: 10.1111/jnc.15724] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Revised: 11/10/2022] [Accepted: 11/16/2022] [Indexed: 11/19/2022]
Abstract
The high prevalence of pain and the at times low efficacy of current treatments represent a significant challenge to healthcare systems worldwide. Effective treatment strategies require consideration of the diverse pathophysiologies that underlie various pain conditions. Indeed, our understanding of the mechanisms contributing to aberrant sensory neuron function has advanced considerably. However, sensory neurons operate in a complex dynamic microenvironment that is controlled by multidirectional interactions of neurons with non-neuronal cells, including immune cells, neuronal accessory cells, fibroblasts, adipocytes, and keratinocytes. Each of these cells constitute and control the microenvironment in which neurons operate, inevitably influencing sensory function and the pathology of pain. This review highlights the importance of the neuronal microenvironment for sensory function and pain, focusing on cellular interactions in the skin, nerves, dorsal root ganglia, and spinal cord. We discuss the current understanding of the mechanisms by which neurons and non-neuronal cells communicate to promote or resolve pain, and how this knowledge could be used for the development of mechanism-based treatments.
Collapse
Affiliation(s)
- Hana Starobova
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, Queensland, Australia
| | - Ammar Alshammari
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, Queensland, Australia
| | - Ingrid G Winkler
- Mater Research Institute, The University of Queensland, Queensland, South Brisbane, Australia
| | - Irina Vetter
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, Queensland, Australia
- The School of Pharmacy, The University of Queensland, Woolloongabba, Queensland, Australia
| |
Collapse
|
17
|
Mießner H, Seidel J, Smith ESJ. In vitro models for investigating itch. Front Mol Neurosci 2022; 15:984126. [PMID: 36385768 PMCID: PMC9644192 DOI: 10.3389/fnmol.2022.984126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Accepted: 10/10/2022] [Indexed: 12/04/2022] Open
Abstract
Itch (pruritus) is a sensation that drives a desire to scratch, a behavior observed in many animals. Although generally short-lasting and not causing harm, there are several pathological conditions where chronic itch is a hallmark symptom and in which prolonged scratching can induce damage. Finding medications to counteract the sensation of chronic itch has proven difficult due to the molecular complexity that involves a multitude of triggers, receptors and signaling pathways between skin, immune and nerve cells. While much has been learned about pruritus from in vivo animal models, they have limitations that corroborate the necessity for a transition to more human disease-like models. Also, reducing animal use should be encouraged in research. However, conducting human in vivo experiments can also be ethically challenging. Thus, there is a clear need for surrogate models to be used in pre-clinical investigation of the mechanisms of itch. Most in vitro models used for itch research focus on the use of known pruritogens. For this, sensory neurons and different types of skin and/or immune cells are stimulated in 2D or 3D co-culture, and factors such as neurotransmitter or cytokine release can be measured. There are however limitations of such simplistic in vitro models. For example, not all naturally occurring cell types are present and there is also no connection to the itch-sensing organ, the central nervous system (CNS). Nevertheless, in vitro models offer a chance to investigate otherwise inaccessible specific cell–cell interactions and molecular pathways. In recent years, stem cell-based approaches and human primary cells have emerged as viable alternatives to standard cell lines or animal tissue. As in vitro models have increased in their complexity, further opportunities for more elaborated means of investigating itch have been developed. In this review, we introduce the latest concepts of itch and discuss the advantages and limitations of current in vitro models, which provide valuable contributions to pruritus research and might help to meet the unmet clinical need for more refined anti-pruritic substances.
Collapse
Affiliation(s)
- Hendrik Mießner
- Department of Pharmacology, University of Cambridge, Cambridge, United Kingdom
- Dermatological Skin Care, Beiersdorf AG, Hamburg, Germany
| | - Judith Seidel
- Dermatological Skin Care, Beiersdorf AG, Hamburg, Germany
| | - Ewan St. John Smith
- Department of Pharmacology, University of Cambridge, Cambridge, United Kingdom
- *Correspondence: Ewan St. John Smith,
| |
Collapse
|
18
|
MAS-related G protein-coupled receptors X (MRGPRX): Orphan GPCRs with potential as targets for future drugs. Pharmacol Ther 2022; 238:108259. [DOI: 10.1016/j.pharmthera.2022.108259] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 07/30/2022] [Accepted: 08/01/2022] [Indexed: 11/20/2022]
|
19
|
Van Remoortel S, Lambeets L, Timmermans JP. Neuro-immune interactions and the role of Mas-related G protein-coupled receptors in the gastrointestinal tract. Anat Rec (Hoboken) 2022; 306:1131-1139. [PMID: 35694864 DOI: 10.1002/ar.25008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 05/11/2022] [Accepted: 05/20/2022] [Indexed: 11/10/2022]
Abstract
Over the past decade, the research field dealing with the role of a new family of Rhodopsin A-like G protein-coupled receptors, that is, the family of Mas-related G protein-coupled receptors (Mrgprs) has expanded enormously. A plethora of recent studies have provided evidence that Mrgprs are key players in itch and pain, as well as in the initiation and modulation of inflammatory/allergic responses in the skin. Over the years, it has become clear that this role is not limited to the skin, but extends to other mucosal surfaces such as the respiratory tract and the gastrointestinal (GI) tract. In the GI tract, Mrgprs have emerged as novel interoceptive sensory pathways linked to health and disease, and are in close functional association with the gut's immune system. This review aims to provide an update of our current knowledge on the expression, distribution and function of members of this Mrgpr family in intrinsic and extrinsic neuro-immune pathways related to the GI system.
Collapse
Affiliation(s)
- Samuel Van Remoortel
- Faculty of Pharmaceutical, Biomedical and Veterinary Sciences, Laboratory of Cell Biology and Histology, University of Antwerp, Antwerp, Belgium
| | - Lana Lambeets
- Faculty of Pharmaceutical, Biomedical and Veterinary Sciences, Laboratory of Cell Biology and Histology, University of Antwerp, Antwerp, Belgium
| | - Jean-Pierre Timmermans
- Faculty of Pharmaceutical, Biomedical and Veterinary Sciences, Laboratory of Cell Biology and Histology, University of Antwerp, Antwerp, Belgium
| |
Collapse
|
20
|
Kwatra SG, Misery L, Clibborn C, Steinhoff M. Molecular and cellular mechanisms of itch and pain in atopic dermatitis and implications for novel therapeutics. Clin Transl Immunology 2022; 11:e1390. [PMID: 35582626 PMCID: PMC9082890 DOI: 10.1002/cti2.1390] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Revised: 04/07/2022] [Accepted: 04/11/2022] [Indexed: 12/03/2022] Open
Abstract
Atopic dermatitis is a chronic inflammatory skin disease. Patients with atopic dermatitis experience inflammatory lesions associated with intense itch and pain, which lead to sleep disturbance and poor mental health and quality of life. We review the molecular mechanisms underlying itch and pain symptoms in atopic dermatitis and discuss the current clinical development of treatments for moderate‐to‐severe atopic dermatitis. The molecular pathology of atopic dermatitis includes aberrant immune activation involving significant cross‐talk among the skin and immune and neuronal cells. Exogenous and endogenous triggers modulate stimulation of mediators including cytokine/chemokine expression/release by the skin and immune cells, which causes inflammation, skin barrier disruption, activation and growth of sensory neurons, itch and pain. These complex interactions among cell types are mediated primarily by cytokines, but also involve chemokines, neurotransmitters, lipids, proteases, antimicrobial peptides, agonists of ion channels or various G protein–coupled receptors. Patients with atopic dermatitis have a cytokine profile characterised by abnormal levels of interleukins 4, 12, 13, 18, 22, 31 and 33; thymic stromal lymphopoietin; and interferon gamma. Cytokine receptors mainly signal through the Janus kinase/signal transducer and activator of transcription pathway. Among emerging novel therapeutics, several Janus kinase inhibitors are being developed for topical or systemic treatment of moderate‐to‐severe atopic dermatitis because of their potential to modulate cytokine expression and release. Janus kinase inhibitors lead to changes in gene expression that have favourable effects on local and systemic cytokine release, and probably other mediators, thus successfully modulating molecular mechanisms responsible for itch and pain in atopic dermatitis.
Collapse
Affiliation(s)
- Shawn G Kwatra
- Department of Dermatology Johns Hopkins University School of Medicine Baltimore MD USA
| | - Laurent Misery
- Department of Dermatology University Hospital of Brest Brest France
| | | | - Martin Steinhoff
- Department of Dermatology and Venereology Hamad Medical Corporation Doha Qatar.,Translational Research Institute Academic Health System Hamad Medical Corporation Doha Qatar.,Dermatology Institute Academic Health System Hamad Medical Corporation Doha Qatar.,Department of Dermatology Weill Cornell Medicine-Qatar Doha Qatar.,Qatar University, College of Medicine Doha Qatar.,Department of Dermatology Weill Cornell Medicine New York NY USA
| |
Collapse
|
21
|
Malewicz NM, Rattray Z, Oeck S, Jung S, Escamilla-Rivera V, Chen Z, Tang X, Zhou J, LaMotte RH. Topical Capsaicin in Poly(lactic-co-glycolic)acid (PLGA) Nanoparticles Decreases Acute Itch and Heat Pain. Int J Mol Sci 2022; 23:5275. [PMID: 35563669 PMCID: PMC9101161 DOI: 10.3390/ijms23095275] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Revised: 04/27/2022] [Accepted: 05/06/2022] [Indexed: 01/27/2023] Open
Abstract
BACKGROUND Capsaicin, the hot pepper agent, produces burning followed by desensitization. To treat localized itch or pain with minimal burning, low capsaicin concentrations can be repeatedly applied. We hypothesized that alternatively controlled release of capsaicin from poly(lactic-co-glycolic acid) (PLGA) nanoparticles desensitizes superficially terminating nociceptors, reducing burning. METHODS Capsaicin-loaded PLGA nanoparticles were prepared (single-emulsion solvent evaporation) and characterized (size, morphology, capsaicin loading, encapsulation efficiency, in vitro release profile). Capsaicin-PLGA nanoparticles were applied to murine skin and evaluated in healthy human participants (n = 21) for 4 days under blinded conditions, and itch and nociceptive sensations evoked by mechanical, heat stimuli and pruritogens cowhage, β-alanine, BAM8-22 and histamine were evaluated. RESULTS Nanoparticles (loading: 58 µg capsaicin/mg) released in vitro 23% capsaicin within the first hour and had complete release at 72 h. In mice, 24 h post-application Capsaicin-PLGA nanoparticles penetrated the dermis and led to decreased nociceptive behavioral responses to heat and mechanical stimulation (desensitization). Application in humans produced a weak to moderate burning, dissipating after 3 h. A loss of heat pain up to 2 weeks was observed. After capsaicin nanoparticles, itch and nociceptive sensations were reduced in response to pruritogens cowhage, β-alanine or BAM8-22, but were normal to histamine. CONCLUSIONS Capsaicin nanoparticles could be useful in reducing pain and itch associated with pruritic diseases that are histamine-independent.
Collapse
Affiliation(s)
- Nathalie M. Malewicz
- Department of Anesthesiology, Yale University School of Medicine, 330 Cedar St, New Haven, CT 06510, USA; (S.J.); (V.E.-R.)
- Clinics for Anesthesiology, Intensive Care and Pain Medicine, Medical Faculty of Ruhr-University Bochum, BG University Hospital Bergmannsheil, 44789 Bochum, Germany
| | - Zahra Rattray
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow G4 0RE, UK;
| | - Sebastian Oeck
- Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, CT 06510, USA;
- Department of Medical Oncology, West German Cancer Center, University Hospital Essen, 45147 Essen, Germany
| | - Sebastian Jung
- Department of Anesthesiology, Yale University School of Medicine, 330 Cedar St, New Haven, CT 06510, USA; (S.J.); (V.E.-R.)
- ZEMOS Center for Solvation Science, Ruhr University Bochum, 44801 Bochum, Germany
| | - Vicente Escamilla-Rivera
- Department of Anesthesiology, Yale University School of Medicine, 330 Cedar St, New Haven, CT 06510, USA; (S.J.); (V.E.-R.)
- Department of Otolaryngology—Head and Neck Surgery, College of Medicine, The University of Arizona, Tucson, AZ 85724, USA
| | - Zeming Chen
- Department of Neurosurgery, Yale University School of Medicine, New Haven, CT 06510, USA; (Z.C.); (X.T.); (J.Z.)
| | - Xiangjun Tang
- Department of Neurosurgery, Yale University School of Medicine, New Haven, CT 06510, USA; (Z.C.); (X.T.); (J.Z.)
| | - Jiangbing Zhou
- Department of Neurosurgery, Yale University School of Medicine, New Haven, CT 06510, USA; (Z.C.); (X.T.); (J.Z.)
| | - Robert H. LaMotte
- Department of Anesthesiology, Yale University School of Medicine, 330 Cedar St, New Haven, CT 06510, USA; (S.J.); (V.E.-R.)
| |
Collapse
|
22
|
Kim BS. The translational revolution of itch. Neuron 2022; 110:2209-2214. [PMID: 35447089 DOI: 10.1016/j.neuron.2022.03.031] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 02/23/2022] [Accepted: 03/24/2022] [Indexed: 02/08/2023]
Abstract
The ability to sense the environment is essential to survival and is the primary purpose of the somatosensory nervous system. However, despite its highly conserved nature, the sensation of itch has been historically overlooked, and its importance in medicine underappreciated. Herein, we highlight how fundamental discoveries, coupled to rapid successes of new therapeutics, have placed itch biology at the forefront of a translational revolution in the field of somatosensation and beyond.
Collapse
Affiliation(s)
- Brian S Kim
- Kimberly and Eric J. Waldman Department of Dermatology, Icahn School of Medicine at Mount Sinai, New York, NY, USA; Mark Lebwohl Center for Neuroinflammation and Sensation, Icahn School of Medicine at Mount Sinai, New York, NY, USA; Precision Immunology Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA; Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
| |
Collapse
|
23
|
Agelopoulos K, Pereira MP, Wiegmann H, Ständer S. Cutaneous neuroimmune crosstalk in pruritus. Trends Mol Med 2022; 28:452-462. [DOI: 10.1016/j.molmed.2022.03.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2022] [Revised: 03/03/2022] [Accepted: 03/16/2022] [Indexed: 10/18/2022]
|
24
|
Steinhoff M, Ahmad F, Pandey A, Datsi A, AlHammadi A, Al-Khawaga S, Al-Malki A, Meng J, Alam M, Buddenkotte J. Neuro-immune communication regulating pruritus in atopic dermatitis. J Allergy Clin Immunol 2022; 149:1875-1898. [PMID: 35337846 DOI: 10.1016/j.jaci.2022.03.010] [Citation(s) in RCA: 44] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2021] [Revised: 02/13/2022] [Accepted: 03/10/2022] [Indexed: 11/26/2022]
Abstract
Atopic dermatitis (AD) is a common, chronic-relapsing inflammatory skin disease with significant disease burden. Genetic and environmental trigger factors contribute to AD, activating two of our largest organs, the nervous and immune system. Dysregulation of neuro-immune circuits plays a key role in the pathophysiology of AD causing inflammation, pruritus, pain, and barrier dysfunction. Sensory nerves can be activated by environmental or endogenous trigger factors transmitting itch stimuli to the brain. Upon stimulation, sensory nerve endings also release neuromediators into the skin contributing again to inflammation, barrier dysfunction and itch. Additionally, dysfunctional peripheral and central neuronal structures contribute to neuroinflammation, sensitization, nerve elongation, neuropathic itch, thus chronification and therapy-resistance. Consequently, neuro-immune circuits in skin and central nervous system may be targets to treat pruritus in AD. Cytokines, chemokines, proteases, lipids, opioids, ions excite/sensitize sensory nerve endings not only induce itch but further aggravate/perpetuate inflammation, skin barrier disruption, and pruritus. Thus, targeted therapies for neuro-immune circuits as well as pathway inhibitors (e.g., kinase inhibitors) may be beneficial to control pruritus in AD either in systemic and/or topical form. Understanding neuro-immune circuits and neuronal signaling will optimize our approach to control all pathological mechanisms in AD, inflammation, barrier dysfunction and pruritus.
Collapse
Affiliation(s)
- Martin Steinhoff
- Department of Dermatology and Venereology, Hamad Medical Corporation, Doha, Qatar; Translational Research Institute, Academic Health System, Hamad Medical Corporation, Doha, Qatar; Dermatology Institute, Academic Health System, Hamad Medical Corporation, Doha, Qatar; Department of Dermatology, Weill Cornell Medicine-Qatar, Doha, Qatar; Qatar University, College of Medicine, Doha, Qatar; Department of Dermatology, Weill Cornell Medicine, New York, USA.
| | - Fareed Ahmad
- Translational Research Institute, Academic Health System, Hamad Medical Corporation, Doha, Qatar; Dermatology Institute, Academic Health System, Hamad Medical Corporation, Doha, Qatar
| | - Atul Pandey
- Translational Research Institute, Academic Health System, Hamad Medical Corporation, Doha, Qatar; Dermatology Institute, Academic Health System, Hamad Medical Corporation, Doha, Qatar
| | - Angeliki Datsi
- Institute for Transplantational Diagnostics and Cell Therapeutics, University Hospital Düsseldorf, Düsseldorf, Germany
| | - Ayda AlHammadi
- Department of Dermatology and Venereology, Hamad Medical Corporation, Doha, Qatar
| | - Sara Al-Khawaga
- Department of Dermatology and Venereology, Hamad Medical Corporation, Doha, Qatar
| | - Aysha Al-Malki
- Department of Dermatology and Venereology, Hamad Medical Corporation, Doha, Qatar
| | - Jianghui Meng
- National Institute for Cellular Biotechnology, Dublin City University, Dublin, Ireland
| | - Majid Alam
- Translational Research Institute, Academic Health System, Hamad Medical Corporation, Doha, Qatar; Dermatology Institute, Academic Health System, Hamad Medical Corporation, Doha, Qatar
| | - Joerg Buddenkotte
- Department of Dermatology and Venereology, Hamad Medical Corporation, Doha, Qatar; Translational Research Institute, Academic Health System, Hamad Medical Corporation, Doha, Qatar; Dermatology Institute, Academic Health System, Hamad Medical Corporation, Doha, Qatar
| |
Collapse
|
25
|
Tavares-Ferreira D, Shiers S, Ray PR, Wangzhou A, Jeevakumar V, Sankaranarayanan I, Cervantes AM, Reese JC, Chamessian A, Copits BA, Dougherty PM, Gereau RW, Burton MD, Dussor G, Price TJ. Spatial transcriptomics of dorsal root ganglia identifies molecular signatures of human nociceptors. Sci Transl Med 2022; 14:eabj8186. [PMID: 35171654 PMCID: PMC9272153 DOI: 10.1126/scitranslmed.abj8186] [Citation(s) in RCA: 143] [Impact Index Per Article: 71.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Nociceptors are specialized sensory neurons that detect damaging or potentially damaging stimuli and are found in the dorsal root ganglia (DRG) and trigeminal ganglia. These neurons are critical for the generation of neuronal signals that ultimately create the perception of pain. Nociceptors are also primary targets for treating acute and chronic pain. Single-cell transcriptomics on mouse nociceptors has transformed our understanding of pain mechanisms. We sought to generate equivalent information for human nociceptors with the goal of identifying transcriptomic signatures of nociceptors, identifying species differences and potential drug targets. We used spatial transcriptomics to molecularly characterize transcriptomes of single DRG neurons from eight organ donors. We identified 12 clusters of human sensory neurons, 5 of which are C nociceptors, as well as 1 C low-threshold mechanoreceptors (LTMRs), 1 Aβ nociceptor, 2 Aδ, 2 Aβ, and 1 proprioceptor subtypes. By focusing on expression profiles for ion channels, G protein-coupled receptors (GPCRs), and other pharmacological targets, we provided a rich map of potential drug targets in the human DRG with direct comparison to mouse sensory neuron transcriptomes. We also compared human DRG neuronal subtypes to nonhuman primates showing conserved patterns of gene expression among many cell types but divergence among specific nociceptor subsets. Last, we identified sex differences in human DRG subpopulation transcriptomes, including a marked increase in calcitonin-related polypeptide alpha (CALCA) expression in female pruritogen receptor-enriched nociceptors. This comprehensive spatial characterization of human nociceptors might open the door to development of better treatments for acute and chronic pain disorders.
Collapse
Affiliation(s)
- Diana Tavares-Ferreira
- Department of Neuroscience and Center for Advanced Pain Studies, University of Texas at Dallas, Richardson TX 75080, USA.,Corresponding author: (T.J.P.); (D.T.-F.)
| | - Stephanie Shiers
- Department of Neuroscience and Center for Advanced Pain Studies, University of Texas at Dallas, Richardson TX 75080, USA
| | - Pradipta R. Ray
- Department of Neuroscience and Center for Advanced Pain Studies, University of Texas at Dallas, Richardson TX 75080, USA
| | - Andi Wangzhou
- Department of Neuroscience and Center for Advanced Pain Studies, University of Texas at Dallas, Richardson TX 75080, USA
| | - Vivekanand Jeevakumar
- Department of Neuroscience and Center for Advanced Pain Studies, University of Texas at Dallas, Richardson TX 75080, USA
| | - Ishwarya Sankaranarayanan
- Department of Neuroscience and Center for Advanced Pain Studies, University of Texas at Dallas, Richardson TX 75080, USA
| | | | | | - Alexander Chamessian
- Department of Anesthesiology, Washington University Pain Center, St. Louis, MO 63110, USA
| | - Bryan A. Copits
- Department of Anesthesiology, Washington University Pain Center, St. Louis, MO 63110, USA
| | - Patrick M. Dougherty
- Department of Pain Medicine, Division of Anesthesiology and Critical Care, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Robert W. Gereau
- Department of Anesthesiology, Washington University Pain Center, St. Louis, MO 63110, USA
| | - Michael D. Burton
- Department of Neuroscience and Center for Advanced Pain Studies, University of Texas at Dallas, Richardson TX 75080, USA
| | - Gregory Dussor
- Department of Neuroscience and Center for Advanced Pain Studies, University of Texas at Dallas, Richardson TX 75080, USA
| | - Theodore J. Price
- Department of Neuroscience and Center for Advanced Pain Studies, University of Texas at Dallas, Richardson TX 75080, USA.,Corresponding author: (T.J.P.); (D.T.-F.)
| |
Collapse
|
26
|
Tavares-Ferreira D, Shiers S, Ray PR, Wangzhou A, Jeevakumar V, Sankaranarayanan I, Cervantes AM, Reese JC, Chamessian A, Copits BA, Dougherty PM, Gereau RW, Burton MD, Dussor G, Price TJ. Spatial transcriptomics of dorsal root ganglia identifies molecular signatures of human nociceptors. Sci Transl Med 2022. [DOI: 10.1126/scitranslmed.abj8186\] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Nociceptors are specialized sensory neurons that detect damaging or potentially damaging stimuli and are found in the dorsal root ganglia (DRG) and trigeminal ganglia. These neurons are critical for the generation of neuronal signals that ultimately create the perception of pain. Nociceptors are also primary targets for treating acute and chronic pain. Single-cell transcriptomics on mouse nociceptors has transformed our understanding of pain mechanisms. We sought to generate equivalent information for human nociceptors with the goal of identifying transcriptomic signatures of nociceptors, identifying species differences and potential drug targets. We used spatial transcriptomics to molecularly characterize transcriptomes of single DRG neurons from eight organ donors. We identified 12 clusters of human sensory neurons, 5 of which are C nociceptors, as well as 1 C low-threshold mechanoreceptors (LTMRs), 1 Aβ nociceptor, 2 Aδ, 2 Aβ, and 1 proprioceptor subtypes. By focusing on expression profiles for ion channels, G protein–coupled receptors (GPCRs), and other pharmacological targets, we provided a rich map of potential drug targets in the human DRG with direct comparison to mouse sensory neuron transcriptomes. We also compared human DRG neuronal subtypes to nonhuman primates showing conserved patterns of gene expression among many cell types but divergence among specific nociceptor subsets. Last, we identified sex differences in human DRG subpopulation transcriptomes, including a marked increase in calcitonin-related polypeptide alpha (
CALCA
) expression in female pruritogen receptor–enriched nociceptors. This comprehensive spatial characterization of human nociceptors might open the door to development of better treatments for acute and chronic pain disorders.
Collapse
Affiliation(s)
- Diana Tavares-Ferreira
- Department of Neuroscience and Center for Advanced Pain Studies, University of Texas at Dallas, Richardson TX 75080, USA
| | - Stephanie Shiers
- Department of Neuroscience and Center for Advanced Pain Studies, University of Texas at Dallas, Richardson TX 75080, USA
| | - Pradipta R. Ray
- Department of Neuroscience and Center for Advanced Pain Studies, University of Texas at Dallas, Richardson TX 75080, USA
| | - Andi Wangzhou
- Department of Neuroscience and Center for Advanced Pain Studies, University of Texas at Dallas, Richardson TX 75080, USA
| | - Vivekanand Jeevakumar
- Department of Neuroscience and Center for Advanced Pain Studies, University of Texas at Dallas, Richardson TX 75080, USA
| | - Ishwarya Sankaranarayanan
- Department of Neuroscience and Center for Advanced Pain Studies, University of Texas at Dallas, Richardson TX 75080, USA
| | | | | | - Alexander Chamessian
- Department of Anesthesiology , Washington University Pain Center, St. Louis, MO 63110, USA
| | - Bryan A. Copits
- Department of Anesthesiology , Washington University Pain Center, St. Louis, MO 63110, USA
| | - Patrick M. Dougherty
- Department of Pain Medicine, Division of Anesthesiology and Critical Care, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Robert W. Gereau
- Department of Anesthesiology , Washington University Pain Center, St. Louis, MO 63110, USA
| | - Michael D. Burton
- Department of Neuroscience and Center for Advanced Pain Studies, University of Texas at Dallas, Richardson TX 75080, USA
| | - Gregory Dussor
- Department of Neuroscience and Center for Advanced Pain Studies, University of Texas at Dallas, Richardson TX 75080, USA
| | - Theodore J. Price
- Department of Neuroscience and Center for Advanced Pain Studies, University of Texas at Dallas, Richardson TX 75080, USA
| |
Collapse
|
27
|
Nguyen MQ, von Buchholtz LJ, Reker AN, Ryba NJ, Davidson S. Single-nucleus transcriptomic analysis of human dorsal root ganglion neurons. eLife 2021; 10:71752. [PMID: 34825887 PMCID: PMC8626086 DOI: 10.7554/elife.71752] [Citation(s) in RCA: 94] [Impact Index Per Article: 31.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Accepted: 11/06/2021] [Indexed: 12/14/2022] Open
Abstract
Somatosensory neurons with cell bodies in the dorsal root ganglia (DRG) project to the skin, muscles, bones, and viscera to detect touch and temperature as well as to mediate proprioception and many types of interoception. In addition, the somatosensory system conveys the clinically relevant noxious sensations of pain and itch. Here, we used single nuclear transcriptomics to characterize transcriptomic classes of human DRG neurons that detect these diverse types of stimuli. Notably, multiple types of human DRG neurons have transcriptomic features that resemble their mouse counterparts although expression of genes considered important for sensory function often differed between species. More unexpectedly, we identified several transcriptomic classes with no clear equivalent in the other species. This dataset should serve as a valuable resource for the community, for example as means of focusing translational efforts on molecules with conserved expression across species.
Collapse
Affiliation(s)
- Minh Q Nguyen
- National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, United States
| | - Lars J von Buchholtz
- National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, United States
| | - Ashlie N Reker
- Department of Anesthesiology, College of Medicine, University of Cincinnati, Cincinnati, United States
| | - Nicholas Jp Ryba
- National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, United States
| | - Steve Davidson
- Department of Anesthesiology, College of Medicine, University of Cincinnati, Cincinnati, United States
| |
Collapse
|
28
|
Microinjection of pruritogens in NGF-sensitized human skin. Sci Rep 2021; 11:21490. [PMID: 34728705 PMCID: PMC8563721 DOI: 10.1038/s41598-021-00935-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 10/19/2021] [Indexed: 11/16/2022] Open
Abstract
Single intradermal injections of nerve growth factor (NGF) evoke prolonged but temporally distinct sensitization patterns to somatosensory stimuli. Focal administration of the non-histaminergic pruritogen cowhage but not histamine resulted in elevated itch at day 21 after NGF administration. Here, we injected bovine adrenal medulla peptide 8–22 (BAM8–22), β-alanine (β-ALA) and endothelin-1 (ET-1) into NGF-treated skin of 11 healthy volunteers and investigated the corresponding itch/pain and flare reactions. β-ALA was the weakest pruritogen, while BAM8–22 and ET-1 were equally potent as histamine. NGF did not sensitize itch or flare reactions induced by any compound, but injection and evoked pain were increased at day 21 and 49. The involvement of histamine H1 receptors in itch was explored in eight subjects after oral cetirizine. ET-1-induced itch and flare were significantly reduced. BAM8–22 and β-ALA itch were not affected, but flare responses after BAM8–22 reduced by 50%. The results indicate that a single NGF injection does not sensitize for experimentally induced itch but increases pain upon pruritogen injection. In healthy humans, pruritic and algetic processing appear differentially regulated by NGF. However, in patients suffering chronic itch, prolonged elevation of NGF-levels under inflammatory conditions may contribute to elevated itch.
Collapse
|