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Heber S, Resch F, Ciotu CI, Gleiss A, Heber UM, Macher-Beer A, Bhuiyan S, Gold-Binder M, Kain R, Sator S, Fischer MJM. Human heat sensation: A randomized crossover trial. SCIENCE ADVANCES 2024; 10:eado3498. [PMID: 39231217 PMCID: PMC11373589 DOI: 10.1126/sciadv.ado3498] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2024] [Accepted: 07/30/2024] [Indexed: 09/06/2024]
Abstract
Sensing of noxious heat has been reported to be mediated by TRPV1, TRPA1, TRPM3, and ANO1 in mice, and this is redundant so that the loss of one receptor is at least partially compensated for by others. We have established an infusion-based human heat pain model. Heat-induced pain probed with antagonists for the four receptors did not match the redundancy found in mice. In healthy participants, only TRPV1 contributes to the detection of noxious heat; none of the other three receptors are involved. TRPV1 inhibition reduced the pain at all noxious temperatures, which can also be seen as an increase in the temperature that causes a particular level of pain. However, even if the TRPV1-dependent shift in heat detection is about 1°C, at the end of the temperature ramp to 52°C, most heat-induced pain remains unexplained. This difference between species reopens the quest for the molecular safety net for the detection of noxious heat in humans.
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Affiliation(s)
- Stefan Heber
- Institute of Physiology, Center for Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Felix Resch
- Institute of Physiology, Center for Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Cosmin I Ciotu
- Institute of Physiology, Center for Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Andreas Gleiss
- Institute of Clinical Biometrics, Center for Medical Data Science, Medical University of Vienna, Vienna, Austria
| | - Ulrike M Heber
- Department of Pathology, Medical University of Vienna, Vienna, Austria
| | | | - Samantha Bhuiyan
- Institute of Physiology, Center for Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Markus Gold-Binder
- Institute of Physiology, Center for Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Renate Kain
- Department of Pathology, Medical University of Vienna, Vienna, Austria
| | - Sabine Sator
- Division of Special Anesthesia and Pain Medicine, Department of Anesthesia, Intensive Care and Pain Medicine, Medical University of Vienna, Vienna, Austria
| | - Michael J M Fischer
- Institute of Physiology, Center for Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
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2
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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.
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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.
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3
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Kutafina E, Becker S, Namer B. Measuring pain and nociception: Through the glasses of a computational scientist. Transdisciplinary overview of methods. FRONTIERS IN NETWORK PHYSIOLOGY 2023; 3:1099282. [PMID: 36926544 PMCID: PMC10013045 DOI: 10.3389/fnetp.2023.1099282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Accepted: 01/04/2023] [Indexed: 02/12/2023]
Abstract
In a healthy state, pain plays an important role in natural biofeedback loops and helps to detect and prevent potentially harmful stimuli and situations. However, pain can become chronic and as such a pathological condition, losing its informative and adaptive function. Efficient pain treatment remains a largely unmet clinical need. One promising route to improve the characterization of pain, and with that the potential for more effective pain therapies, is the integration of different data modalities through cutting edge computational methods. Using these methods, multiscale, complex, and network models of pain signaling can be created and utilized for the benefit of patients. Such models require collaborative work of experts from different research domains such as medicine, biology, physiology, psychology as well as mathematics and data science. Efficient work of collaborative teams requires developing of a common language and common level of understanding as a prerequisite. One of ways to meet this need is to provide easy to comprehend overviews of certain topics within the pain research domain. Here, we propose such an overview on the topic of pain assessment in humans for computational researchers. Quantifications related to pain are necessary for building computational models. However, as defined by the International Association of the Study of Pain (IASP), pain is a sensory and emotional experience and thus, it cannot be measured and quantified objectively. This results in a need for clear distinctions between nociception, pain and correlates of pain. Therefore, here we review methods to assess pain as a percept and nociception as a biological basis for this percept in humans, with the goal of creating a roadmap of modelling options.
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Affiliation(s)
- Ekaterina Kutafina
- Institute of Medical Informatics, Medical Faculty, RWTH Aachen University, Aachen, Germany
- Faculty of Applied Mathematics, AGH University of Science and Technology, Krakow, Poland
| | - Susanne Becker
- Clinical Psychology, Department of Experimental Psychology, Heinrich Heine University, Düsseldorf, Germany
- Integrative Spinal Research, Department of Chiropractic Medicine, University Hospital Balgrist, University of Zurich, Zurich, Switzerland
- Department of Cognitive and Clinical Neuroscience, Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Barbara Namer
- Junior Research Group Neuroscience, Interdisciplinary Center for Clinical Research Within the Faculty of Medicine, RWTH Aachen University, Aachen, Germany
- Institute of Physiology, Medical Faculty, RWTH Aachen University, Aachen, Germany
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4
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Liang Q, Qiao Z, Zhou Q, Xue D, Wang K, Shao L. Discovery of Potent and Selective Transient Receptor Potential Vanilloid 1 (TRPV1) Agonists with Analgesic Effects In Vivo Based on the Functional Conversion Induced by Altering the Orientation of the Indazole Core. J Med Chem 2022; 65:11658-11678. [PMID: 36008373 DOI: 10.1021/acs.jmedchem.2c00469] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Transient receptor potential vanilloid 1 (TRPV1) is a promising target for developing antinociceptive agents. Here, we report the synthesis of N-indazole-4-aryl piperazine carboxamide analogues as TRPV1 modulators. The structure-activity relationship (SAR) reveals that substituting indazole at the 5-/6-position leads to TRPV1 agonism, whereas the 4- and 7-positions of indazole obtain mild antagonism and loss of activity, respectively. The whole-cell clamp patch assay shows that 28 is a potent and selective TRPV1 agonist and it relieves inflammatory and thermal pain by desensitizing the native TRPV1 current in the dorsal root ganglion (DRG) in mice. Additionally, site-directed mutagenesis combined with molecular docking shows an important hydrogen interaction between Arg557 and the indazole of 28. Taken together, our findings provide insight into TRPV1 agonism-antagonism conversion based on the interaction between indazole and Arg557, which provides a strategy to obtain new TRPV1 agonists by structural modification of antagonists. Compound 28 may be used as a lead compound for further optimization.
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Affiliation(s)
- Qianqian Liang
- Department of Medicinal Chemistry, School of Pharmacy, Fudan University, 826 Zhangheng Road, Shanghai 201203, China
| | - Zhen Qiao
- Department of Medicinal Chemistry, School of Pharmacy, Fudan University, 826 Zhangheng Road, Shanghai 201203, China
| | - Qiqi Zhou
- Department of Pharmacology, Qilu Medical University, Zibo, Shandong 255300, China
| | - Dengqi Xue
- Department of Medicinal Chemistry, School of Pharmacy, Fudan University, 826 Zhangheng Road, Shanghai 201203, China.,State Key Laboratory of Medical Neurobiology, Fudan University, 138 Yixueyuan Road, Shanghai 200032, China
| | - KeWei Wang
- Departments of Pharmacology, School of Pharmacy, Qingdao University Medical College, #1 Ningde Road, Qingdao 266073, China.,Institute of Innovative Drug Discovery, Qingdao University, 38 Dengzhou Road, Qingdao 266021, China
| | - Liming Shao
- Department of Medicinal Chemistry, School of Pharmacy, Fudan University, 826 Zhangheng Road, Shanghai 201203, China.,State Key Laboratory of Medical Neurobiology, Fudan University, 138 Yixueyuan Road, Shanghai 200032, China
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5
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Vasavda C, Xu R, Liew J, Kothari R, Dhindsa RS, Semenza ER, Paul BD, Green DP, Sabbagh MF, Shin JY, Yang W, Snowman AM, Albacarys LK, Moghekar A, Pardo-Villamizar CA, Luciano M, Huang J, Bettegowda C, Kwatra SG, Dong X, Lim M, Snyder SH. Identification of the NRF2 transcriptional network as a therapeutic target for trigeminal neuropathic pain. SCIENCE ADVANCES 2022; 8:eabo5633. [PMID: 35921423 PMCID: PMC9348805 DOI: 10.1126/sciadv.abo5633] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2022] [Accepted: 06/16/2022] [Indexed: 05/28/2023]
Abstract
Trigeminal neuralgia, historically dubbed the "suicide disease," is an exceedingly painful neurologic condition characterized by sudden episodes of intense facial pain. Unfortunately, the only U.S. Food and Drug Administration (FDA)-approved medication for trigeminal neuralgia carries substantial side effects, with many patients requiring surgery. Here, we identify the NRF2 transcriptional network as a potential therapeutic target. We report that cerebrospinal fluid from patients with trigeminal neuralgia accumulates reactive oxygen species, several of which directly activate the pain-transducing channel TRPA1. Similar to our patient cohort, a mouse model of trigeminal neuropathic pain also exhibits notable oxidative stress. We discover that stimulating the NRF2 antioxidant transcriptional network is as analgesic as inhibiting TRPA1, in part by reversing the underlying oxidative stress. Using a transcriptome-guided drug discovery strategy, we identify two NRF2 network modulators as potential treatments. One of these candidates, exemestane, is already FDA-approved and may thus be a promising alternative treatment for trigeminal neuropathic pain.
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Affiliation(s)
- Chirag Vasavda
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Risheng Xu
- Department of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Jason Liew
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Ruchita Kothari
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Ryan S. Dhindsa
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
- Jan and Dan Duncan Neurological Research Institute at Texas Children’s Hospital, Houston, TX, USA
| | - Evan R. Semenza
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Bindu D. Paul
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Dustin P. Green
- Department of Neuroscience, Cell Biology, and Anatomy, University of Texas Medical Branch, Galveston, TX, USA
| | - Mark F. Sabbagh
- Department of Pathology, Massachusetts General Hospital, Boston, MA, USA
| | - Joseph Y. Shin
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Wuyang Yang
- Department of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Adele M. Snowman
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Lauren K. Albacarys
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Abhay Moghekar
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | | | - Mark Luciano
- Department of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Judy Huang
- Department of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Chetan Bettegowda
- Department of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Shawn G. Kwatra
- Department of Dermatology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Xinzhong Dong
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Department of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Department of Dermatology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Michael Lim
- Department of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Department of Neurosurgery, Stanford University School of Medicine, Palo Alto, CA, USA
| | - Solomon H. Snyder
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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6
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Rosenbaum T, Morales-Lázaro SL, Islas LD. TRP channels: a journey towards a molecular understanding of pain. Nat Rev Neurosci 2022; 23:596-610. [PMID: 35831443 DOI: 10.1038/s41583-022-00611-7] [Citation(s) in RCA: 28] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/08/2022] [Indexed: 12/18/2022]
Abstract
The perception of nociceptive signals, which are translated into pain, plays a fundamental role in the survival of organisms. Because pain is linked to a negative sensation, animals learn to avoid noxious signals. These signals are detected by receptors, which include some members of the transient receptor potential (TRP) family of ion channels that act as transducers of exogenous and endogenous noxious cues. These proteins have been in the focus of the field of physiology for several years, and much knowledge of how they regulate the function of the cell types and organs where they are expressed has been acquired. The last decade has been especially exciting because the 'resolution revolution' has allowed us to learn the molecular intimacies of TRP channels using cryogenic electron microscopy. These findings, in combination with functional studies, have provided insights into the role played by these channels in the generation and maintenance of pain.
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Affiliation(s)
- Tamara Rosenbaum
- Departamento de Neurociencia Cognitiva, Instituto de Fisiología Celular, UNAM, Mexico City, Mexico.
| | - Sara L Morales-Lázaro
- Departamento de Neurociencia Cognitiva, Instituto de Fisiología Celular, UNAM, Mexico City, Mexico
| | - León D Islas
- Departamento de Fisiología, Facultad de Medicina, UNAM, Mexico City, Mexico
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7
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Courtin AS, Mouraux A. Combining Topical Agonists With the Recording of Event-Related Brain Potentials to Probe the Functional Involvement of TRPM8, TRPA1 and TRPV1 in Heat and Cold Transduction in the Human Skin. THE JOURNAL OF PAIN 2022; 23:754-771. [PMID: 34863944 DOI: 10.1016/j.jpain.2021.11.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Revised: 11/04/2021] [Accepted: 11/18/2021] [Indexed: 06/13/2023]
Abstract
TRP channels play a central role in the transduction of thermal and nociceptive stimuli by free nerve endings. Most of the research on these channels has been conducted in vitro or in vivo in nonhuman animals and translation of these results to humans must account for potential experimental biases and interspecific differences. This study aimed at evaluating the involvement of TRPM8, TRPA1 and TRPV1 channels in the transduction of heat and cold stimuli by the human thermonociceptive system. For this purpose, we evaluated the effects of topical agonists of these 3 channels (menthol, cinnamaldehyde and capsaicin) on the event-related brain potentials (ERPs) elicited by phasic thermal stimuli (target temperatures: 10°C, 42°C, and 60°C) selected to activate cold Aδ thermoreceptors, warm sensitive C thermoreceptors and heat sensitive Aδ polymodal nociceptors. Sixty-four participants were recruited, 16 allocated to each agonist solution group (20% menthol, 10% cinnamaldehyde, .025% capsaicin and 1% capsaicin). Participants were treated sequentially with the active solution on one forearm and vehicle only on the other forearm for 20 minutes. Menthol decreased the amplitude and increased the latency of cold and heat ERPs. Cinnamic aldehyde decreased the amplitude and increased the latency of heat but not cold ERPs. Capsaicin decreased the amplitude and increased the latency of heat ERPs and decreased the amplitude of the N2P2 complex of the cold ERPs without affecting the earlier N1 wave or the latencies of the peaks. These findings are compatible with previous evidence indicating that TRPM8 is involved in innocuous cold transduction and that TRPV1 and TRPA1 are involved in noxious heat transduction in humans. PERSPECTIVE: By chemically modulating TRPM8, TRPA1 and TRPV1 reactivity (key molecules in the transduction of temperature) and assessing how this affected EEG responses to the activation of cold thermoreceptors and heat nociceptors, we aimed at confirming the role of these channels in a functional healthy human model.
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Affiliation(s)
- Arthur S Courtin
- Institute of NeuroScience, Université catholique de Louvain, Brussels, Belgium.
| | - André Mouraux
- Institute of NeuroScience, Université catholique de Louvain, Brussels, Belgium
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8
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Mahajan N, Khare P, Kondepudi KK, Bishnoi M. TRPA1: Pharmacology, natural activators and role in obesity prevention. Eur J Pharmacol 2021; 912:174553. [PMID: 34627805 DOI: 10.1016/j.ejphar.2021.174553] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Revised: 10/05/2021] [Accepted: 10/05/2021] [Indexed: 12/26/2022]
Abstract
Transient receptor potential ankyrin 1 (TRPA1) channel is a calcium permeable, non-selective cation channel, expressed in the sensory neurons and non-neuronal cells of different tissues. Initially studied for its role in pain and inflammation, TRPA1 has now functionally involved in multiple other physiological functions. TRPA1 channel has been extensively studied for modulation by pungent compounds present in the spices and herbs. In the last decade, the role of TRPA1 agonism in body weight reduction, secretion of hunger and satiety hormones, insulin secretion and thermogenesis, has unveiled the potential of the TRPA1 channel to be used as a preventive target to tackle obesity and associated comorbidities including insulin resistance in type 2 diabetes. In this review, we summarized the recent findings of TRPA1 based dietary/non-dietary modulation for its role in obesity prevention and therapeutics.
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Affiliation(s)
- Neha Mahajan
- Centre of Excellence in Functional Foods, Department of Food and Nutritional Biotechnology, National Agri-food Biotechnology Institute (NABI), Knowledge City-Sector-81, SAS Nagar, Punjab 140306, India; Regional Centre for Biotechnology, Faridabad-Gurgaon Expressway, Faridabad, Haryana 121001, India
| | - Pragyanshu Khare
- Centre of Excellence in Functional Foods, Department of Food and Nutritional Biotechnology, National Agri-food Biotechnology Institute (NABI), Knowledge City-Sector-81, SAS Nagar, Punjab 140306, India
| | - Kanthi Kiran Kondepudi
- Centre of Excellence in Functional Foods, Department of Food and Nutritional Biotechnology, National Agri-food Biotechnology Institute (NABI), Knowledge City-Sector-81, SAS Nagar, Punjab 140306, India
| | - Mahendra Bishnoi
- Centre of Excellence in Functional Foods, Department of Food and Nutritional Biotechnology, National Agri-food Biotechnology Institute (NABI), Knowledge City-Sector-81, SAS Nagar, Punjab 140306, India.
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9
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Dulai JS, Smith ESJ, Rahman T. Acid-sensing ion channel 3: An analgesic target. Channels (Austin) 2021; 15:94-127. [PMID: 33258401 PMCID: PMC7801124 DOI: 10.1080/19336950.2020.1852831] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Accepted: 11/13/2020] [Indexed: 12/12/2022] Open
Abstract
Acid-sensing ion channel 3 (ASIC3) belongs to the epithelial sodium channel/degenerin (ENaC/DEG) superfamily. There are 7 different ASIC subunits encoded by 5 different genes. Most ASIC subunits form trimeric ion channels that upon activation by extracellular protons mediate a transient inward current inducing cellular excitability. ASIC subunits exhibit differential tissue expression and biophysical properties, and the ability of subunits to form homo- and heteromeric trimers further increases the complexity of currents measured and their pharmacological properties. ASIC3 is of particular interest, not only because it exhibits high expression in sensory neurones, but also because upon activation it does not fully inactivate: a transient current is followed by a sustained current that persists during a period of extracellular acidity, i.e. ASIC3 can encode prolonged acidosis as a nociceptive signal. Furthermore, certain mediators sensitize ASIC3 enabling smaller proton concentrations to activate it and other mediators can directly activate the channel at neutral pH. Moreover, there is a plethora of evidence using transgenic mouse models and pharmacology, which supports ASIC3 as being a potential target for development of analgesics. This review will focus on current understanding of ASIC3 function to provide an overview of how ASIC3 contributes to physiology and pathophysiology, examining the mechanisms by which it can be modulated, and highlighting gaps in current understanding and future research directions.
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Affiliation(s)
| | | | - Taufiq Rahman
- Department of Pharmacology, University of Cambridge, Cambridge, UK
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10
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Lysophosphatidic acid activates nociceptors and causes pain or itch depending on the application mode in human skin. Pain 2021; 163:445-460. [PMID: 34166323 DOI: 10.1097/j.pain.0000000000002363] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2020] [Accepted: 04/13/2021] [Indexed: 11/26/2022]
Abstract
ABSTRACT Lysophosphatidic acid (LPA) is involved in the pathophysiology of cholestatic pruritus and neuropathic pain. Slowly conducting peripheral afferent C-nerve fibers are crucial in the sensations of itch and pain. In animal studies, specialized neurons ("pruriceptors") have been described, expressing specific receptors e.g. from the Mrgpr family. Human nerve fibers involved in pain signaling ("nociceptors") can elicit itch if activated by focalized stimuli such as cowhage spicules.In this study, we scrutinized the effects of LPA in humans by two different application modes on the level of psychophysics and single nerve fiber recordings (microneurography). In healthy human subjects, intracutaneous LPA microinjections elicited burning pain, whereas LPA application via inactivated cowhage spicules evoked a moderate itch sensation. LPA microinjections induced heat hyperalgesia and hypersensitivity to higher electrical stimulus frequencies. Pharmacological blockade of TRPA1 or TRPV1 reduced heat hyperalgesia but not acute chemical pain. Microneurography revealed an application mode-dependent differential activation of mechano-sensitive (CM) and mechano-insensitive (CMi) C-fibers. LPA microinjections activated a greater proportion of CMi and more strongly than CM fibers; spicule-application of LPA activated CM and CMi fibers to a similar extent but excited CM more and CMi fibers less intensely than microinjections.In conclusion, we show for the first time in humans that LPA can cause pain as well as itch dependent on the mode of application and activates afferent human C-fibers. Itch may arise from focal activation of few nerve fibers with distinct spatial contrast to unexcited surrounding afferents, and a specific combination of activated fiber subclasses might contribute.
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Abstract
Tissue acidosis due to ischemia occurs under several pathological conditions and is believed to contribute to pain in these circumstances. TRPV1, TRPA1, and ASICs are known to be sensitive to acidic pH. Addressing their possible role in acidosis perception, the respective antagonists BCTC, A-967079, and amiloride were injected in the volar forearm skin of 32 healthy volunteers. To investigate possible redundancies between channels, a full-factorial study design was used. Injections were performed in a prerandomized, double-blind, and balanced design. Each injection included a three-step pH protocol from pH 7.0 over pH 6.5 to pH 6.0 with a step duration of 90 seconds. Pain was reported by volunteers on a numerical scale every 10 seconds during injections. Confirming the primary hypothesis, the combination of all 3 antagonists reduced acid-induced pain at pH 6.0. Because of the full-factorial design, it could be concluded that BCTC alone, but not A-967079 or amiloride, or any combination thereof, was responsible for the observed effects, suggesting TRPV1 as primary sensor for pH 6.0-induced pain. Surprisingly, A-967079 even enhanced pain induced by pH 6.0. In cultured mouse dorsal root ganglion neurons, TPRV1 dependence of pH 6-induced calcium responses could be confirmed. Responses of hTRPV1 to acidic stimulation showed a maximum around pH6, providing an explanation for the pH-dependent inhibition by BCTC. A-967079 sensitizes pH responses is a TRPA1-responsive dorsal root ganglion neuron population, and a direct effect of A-967079 on hTRPA1 and hTRPV1 was excluded. In conclusion, inhibiting TRPV1-mediated acidosis-induced pain could be a symptomatic and potentially also a disease-modifying approach.
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The Somatosensory World of the African Naked Mole-Rat. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1319:197-220. [PMID: 34424517 DOI: 10.1007/978-3-030-65943-1_7] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The naked mole-rat (Heterocephalus glaber) is famous for its longevity and unusual physiology. This eusocial species that lives in highly ordered and hierarchical colonies with a single breeding queen, also discovered secrets enabling somewhat pain-free living around 20 million years ago. Unlike most mammals, naked mole-rats do not feel the burn of chili pepper's active ingredient, capsaicin, nor the sting of acid. Indeed, by accumulating mutations in genes encoding proteins that are only now being exploited as targets for new pain therapies (the nerve growth factor receptor TrkA and voltage-gated sodium channel, NaV1.7), this species mastered the art of analgesia before humans evolved. Recently, we have identified pain-insensitivity as a trait shared by several closely related African mole-rat species. In this chapter we will show how African mole-rats have evolved pain insensitivity as well as discussing what the proximate factors may have been that led to the evolution of pain-free traits.
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Fischer MJM, Ciotu CI, Szallasi A. The Mysteries of Capsaicin-Sensitive Afferents. Front Physiol 2020; 11:554195. [PMID: 33391007 PMCID: PMC7772409 DOI: 10.3389/fphys.2020.554195] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Accepted: 11/13/2020] [Indexed: 12/11/2022] Open
Abstract
A fundamental subdivision of nociceptive sensory neurons is named after their unique sensitivity to capsaicin, the pungent ingredient in hot chili peppers: these are the capsaicin-sensitive afferents. The initial excitation by capsaicin of these neurons manifested as burning pain sensation is followed by a lasting refractory state, traditionally referred to as "capsaicin desensitization," during which the previously excited neurons are unresponsive not only to capsaicin but a variety of unrelated stimuli including noxious heat. The long sought-after capsaicin receptor, now known as TRPV1 (transient receptor potential cation channel, subfamily V member 1), was cloned more than two decades ago. The substantial reduction of the inflammatory phenotype of Trpv1 knockout mice has spurred extensive efforts in the pharmaceutical industry to develop small molecule TRPV1 antagonists. However, adverse effects, most importantly hyperthermia and burn injuries, have so far prevented any compounds from progressing beyond Phase 2. There is increasing evidence that these limitations can be at least partially overcome by approaches outside of the mainstream pharmaceutical development, providing novel therapeutic options through TRPV1. Although ablation of the whole TRPV1-expressing nerve population by high dose capsaicin, or more selectively by intersectional genetics, has allowed researchers to investigate the functions of capsaicin-sensitive afferents in health and disease, several "mysteries" remain unsolved to date, including the molecular underpinnings of "capsaicin desensitization," and the exact role these nerves play in thermoregulation and heat sensation. This review tries to shed some light on these capsaicin mechanisms.
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Affiliation(s)
- Michael J. M. Fischer
- Center of Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Cosmin I. Ciotu
- Center of Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Arpad Szallasi
- 1st Department of Pathology and Experimental Cancer Research, Semmelweis University, Budapest, Hungary
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Skok K, Duh M, Stožer A, Markota A, Gosak M. Thermoregulation: A journey from physiology to computational models and the intensive care unit. WILEY INTERDISCIPLINARY REVIEWS. SYSTEMS BIOLOGY AND MEDICINE 2020; 13:e1513. [PMID: 33251759 DOI: 10.1002/wsbm.1513] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 10/24/2020] [Accepted: 11/02/2020] [Indexed: 12/19/2022]
Abstract
Thermoregulation plays a vital role in homeostasis. Many species of animals as well as humans have evolved various physiological mechanisms for body temperature control, which are characteristically flexible and enable a fine-tuned spatial and temporal regulation of body temperature in different environmental conditions and circumstances. Human beings normally maintain a core body temperature at around 37°C, and maintenance of this relatively high temperature is critical for survival. Therefore, principles of thermoregulatory control have also important clinical implications. Infections can cause the body temperature to rise internally and several diseases can cause a dysfunction of thermoregulatory mechanisms. Moreover, the utilization of thermotherapies in treating various diseases has been known for thousands of years with a recent resurgence of interest. An increasing amount of research suggests that targeted temperature management is of paramount importance to patient outcomes in certain clinical scenarios. We provide a concise summary of the basic concepts of thermoregulation. Emphasis is given to the principles of thermoregulation in humans in basic pathological states and to targeted temperature management strategies in the clinical environment, with special attention on therapeutic hypothermia in postcardiac arrest patients. Finally, the discussion is focused on the potential offered by computational thermophysiological models for predicting thermal responses of patients in various clinical circumstances, for proposing new perspectives in the design of novel thermal therapies, and to optimize targeted temperature management strategies. This article is categorized under: Cardiovascular Diseases > Cardiovascular Diseases>Computational Models Cardiovascular Diseases > Cardiovascular Diseases>Environmental Factors Cardiovascular Diseases > Cardiovascular Diseases>Biomedical Engineering.
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Affiliation(s)
- Kristijan Skok
- Department of Pathology, General Hospital Graz II, Location West, Graz, Austria
- Faculty of Medicine, University of Maribor, Maribor, Slovenia
| | - Maja Duh
- Faculty of Natural Sciences and Mathematics, University of Maribor, Koros̆ka cesta, Maribor, Slovenia
| | - Andraž Stožer
- Faculty of Medicine, University of Maribor, Maribor, Slovenia
| | - Andrej Markota
- Faculty of Medicine, University of Maribor, Maribor, Slovenia
- Medical Intensive Care Unit, University Medical Centre Maribor, Maribor, Slovenia
| | - Marko Gosak
- Faculty of Medicine, University of Maribor, Maribor, Slovenia
- Faculty of Natural Sciences and Mathematics, University of Maribor, Koros̆ka cesta, Maribor, Slovenia
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Hockley JR, Barker KH, Taylor TS, Callejo G, Husson ZM, Bulmer DC, Smith ESJ. Acid and inflammatory sensitisation of naked mole-rat colonic afferent nerves. Mol Pain 2020; 16:1744806920903150. [PMID: 31992138 PMCID: PMC6990608 DOI: 10.1177/1744806920903150] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Acid sensing in the gastrointestinal tract is required for gut homeostasis and the detection of tissue acidosis caused by ischaemia, inflammation and infection. In the colorectum, activation of colonic afferents by low pH contributes to visceral hypersensitivity and abdominal pain in human disease including during inflammatory bowel disease. The naked mole-rat (Heterocephalus glaber) shows no pain-related behaviour to subcutaneous acid injection and cutaneous afferents are insensitive to acid, an adaptation thought to be a consequence of the subterranean, likely hypercapnic, environment in which it lives. As such we sought to investigate naked mole-rat interoception within the gastrointestinal tract and how this differed from the mouse (Mus Musculus). Here, we show the presence of calcitonin gene-related peptide expressing extrinsic nerve fibres innervating both mesenteric blood vessels and the myenteric plexi of the smooth muscle layers of the naked mole-rat colorectum. Using ex vivo colonic-nerve electrophysiological recordings, we show differential sensitivity of naked mole-rat, compared to mouse, colonic afferents to acid and the prototypic inflammatory mediator bradykinin, but not direct mechanical stimuli. In naked mole-rat, but not mouse, we observed mechanical hypersensitivity to acid, whilst both species sensitised to bradykinin. Collectively, these findings suggest that naked mole-rat colonic afferents are capable of detecting acidic stimuli; however, their intracellular coupling to downstream molecular effectors of neuronal excitability and mechanotransduction likely differs between species.
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Affiliation(s)
- James Rf Hockley
- Department of Pharmacology, University of Cambridge, Cambridge, UK
| | - Katie H Barker
- Department of Pharmacology, University of Cambridge, Cambridge, UK
| | - Toni S Taylor
- Department of Pharmacology, University of Cambridge, Cambridge, UK
| | - Gerard Callejo
- Department of Pharmacology, University of Cambridge, Cambridge, UK
| | - Zoe M Husson
- Department of Pharmacology, University of Cambridge, Cambridge, UK
| | - David C Bulmer
- Department of Pharmacology, University of Cambridge, Cambridge, UK
| | - Ewan St J Smith
- Department of Pharmacology, University of Cambridge, Cambridge, UK
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16
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Abstract
The endogenous metabolite methylglyoxal (MG) accumulates in diabetic patients with neuropathic pain. Methylglyoxal could be a mediator of diabetes-induced neuropathic pain through TRPA1 activation and sensitization of the voltage-gated sodium channel subtype 1.8. In this study, we tested the algogenic and sensitizing effect of MG in healthy human subjects using intracutaneous microinjections. The involvement of C fibers was assessed through selective A-fiber nerve block, axon-reflex-erythema, and through single nerve fiber recordings in humans (microneurography). Involvement of the transduction channels TRPA1 and TRPV1 in MG-induced pain sensation was investigated with specific ion channel blockers. We showed for the first time in healthy humans that MG induces pain, axon-reflex-erythema, and long-lasting hyperalgesia through the activation of C nociceptors. Predominantly, the subclass of mechano-insensitive C fibers is activated by MG. A fibers contribute only negligibly to the burning pain sensation. Selective pharmacological blockade of TRPA1 or TRPV1 showed that TRPA1 is crucially involved in MG-induced chemical pain sensation and heat hyperalgesia. In conclusion, the actions of MG through TRPA1 activation on predominantly mechano-insensitive C fibers might be involved in spontaneously perceived pain in diabetic neuropathy and hyperalgesia as well as allodynia.
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17
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Smith ESJ, Park TJ, Lewin GR. Independent evolution of pain insensitivity in African mole-rats: origins and mechanisms. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2020; 206:313-325. [PMID: 32206859 PMCID: PMC7192887 DOI: 10.1007/s00359-020-01414-w] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 02/10/2020] [Accepted: 02/27/2020] [Indexed: 12/21/2022]
Abstract
The naked mole-rat (Heterocephalus glaber) is famous for its longevity and unusual physiology. This eusocial species that lives in highly ordered and hierarchical colonies with a single breeding queen, also discovered secrets enabling somewhat pain-free living around 20 million years ago. Unlike most mammals, naked mole-rats do not feel the burn of chili pepper's active ingredient, capsaicin, nor the sting of acid. Indeed, by accumulating mutations in genes encoding proteins that are only now being exploited as targets for new pain therapies (the nerve growth factor receptor TrkA and voltage-gated sodium channel, NaV1.7), this species mastered the art of analgesia before humans evolved. Recently, we have identified pain insensitivity as a trait shared by several closely related African mole-rat species. One of these African mole-rats, the Highveld mole-rat (Cryptomys hottentotus pretoriae), is uniquely completely impervious and pain free when confronted with electrophilic compounds that activate the TRPA1 ion channel. The Highveld mole-rat has evolved a biophysical mechanism to shut down the activation of sensory neurons that drive pain. In this review, we will show how mole-rats have evolved pain insensitivity as well as discussing what the proximate factors may have been that led to the evolution of pain-free traits.
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Affiliation(s)
- Ewan St John Smith
- Department of Pharmacology, University of Cambridge, Cambridge, CB2 1PD, UK
| | - Thomas J Park
- Laboratory of Integrative Neuroscience, Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL, USA
| | - Gary R Lewin
- Molecular Physiology of Somatic Sensation, Max Delbrück Center for Molecular Medicine, Robert-Rössle Str. 10, D-13125, Berlin, Germany.
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18
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Kawashita T, Dunnsiri T, Shu S, Woo BKP. Clinical consideration in evaluating soreness symptoms of fibromyalgia. J Formos Med Assoc 2019; 119:888. [PMID: 31862232 DOI: 10.1016/j.jfma.2019.11.023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Accepted: 11/29/2019] [Indexed: 12/28/2022]
Affiliation(s)
| | | | - Sara Shu
- 14445 Olive View Dr, Sylmar, CA 91342, USA
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19
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Pattison LA, Callejo G, St John Smith E. Evolution of acid nociception: ion channels and receptors for detecting acid. Philos Trans R Soc Lond B Biol Sci 2019; 374:20190291. [PMID: 31544616 PMCID: PMC6790391 DOI: 10.1098/rstb.2019.0291] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/27/2019] [Indexed: 12/13/2022] Open
Abstract
Nociceptors, i.e. sensory neurons tuned to detect noxious stimuli, are found in numerous phyla of the Animalia kingdom and are often polymodal, responding to a variety of stimuli, e.g. heat, cold, pressure and chemicals, such as acid. Owing to the ability of protons to have a profound effect on ionic homeostasis and damage macromolecular structures, it is no wonder that the ability to detect acid is conserved across many species. To detect changes in pH, nociceptors are equipped with an assortment of different acid sensors, some of which can detect mild changes in pH, such as the acid-sensing ion channels, proton-sensing G protein-coupled receptors and several two-pore potassium channels, whereas others, such as the transient receptor potential vanilloid 1 ion channel, require larger shifts in pH. This review will discuss the evolution of acid sensation and the different mechanisms by which nociceptors can detect acid. This article is part of the Theo Murphy meeting issue 'Evolution of mechanisms and behaviour important for pain'.
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Affiliation(s)
| | | | - Ewan St John Smith
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD, UK
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20
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Talavera K, Startek JB, Alvarez-Collazo J, Boonen B, Alpizar YA, Sanchez A, Naert R, Nilius B. Mammalian Transient Receptor Potential TRPA1 Channels: From Structure to Disease. Physiol Rev 2019; 100:725-803. [PMID: 31670612 DOI: 10.1152/physrev.00005.2019] [Citation(s) in RCA: 218] [Impact Index Per Article: 43.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The transient receptor potential ankyrin (TRPA) channels are Ca2+-permeable nonselective cation channels remarkably conserved through the animal kingdom. Mammals have only one member, TRPA1, which is widely expressed in sensory neurons and in non-neuronal cells (such as epithelial cells and hair cells). TRPA1 owes its name to the presence of 14 ankyrin repeats located in the NH2 terminus of the channel, an unusual structural feature that may be relevant to its interactions with intracellular components. TRPA1 is primarily involved in the detection of an extremely wide variety of exogenous stimuli that may produce cellular damage. This includes a plethora of electrophilic compounds that interact with nucleophilic amino acid residues in the channel and many other chemically unrelated compounds whose only common feature seems to be their ability to partition in the plasma membrane. TRPA1 has been reported to be activated by cold, heat, and mechanical stimuli, and its function is modulated by multiple factors, including Ca2+, trace metals, pH, and reactive oxygen, nitrogen, and carbonyl species. TRPA1 is involved in acute and chronic pain as well as inflammation, plays key roles in the pathophysiology of nearly all organ systems, and is an attractive target for the treatment of related diseases. Here we review the current knowledge about the mammalian TRPA1 channel, linking its unique structure, widely tuned sensory properties, and complex regulation to its roles in multiple pathophysiological conditions.
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Affiliation(s)
- Karel Talavera
- Laboratory of Ion Channel Research, Department of Cellular and Molecular Medicine, KU Leuven; VIB Center for Brain and Disease Research, Leuven, Belgium
| | - Justyna B Startek
- Laboratory of Ion Channel Research, Department of Cellular and Molecular Medicine, KU Leuven; VIB Center for Brain and Disease Research, Leuven, Belgium
| | - Julio Alvarez-Collazo
- Laboratory of Ion Channel Research, Department of Cellular and Molecular Medicine, KU Leuven; VIB Center for Brain and Disease Research, Leuven, Belgium
| | - Brett Boonen
- Laboratory of Ion Channel Research, Department of Cellular and Molecular Medicine, KU Leuven; VIB Center for Brain and Disease Research, Leuven, Belgium
| | - Yeranddy A Alpizar
- Laboratory of Ion Channel Research, Department of Cellular and Molecular Medicine, KU Leuven; VIB Center for Brain and Disease Research, Leuven, Belgium
| | - Alicia Sanchez
- Laboratory of Ion Channel Research, Department of Cellular and Molecular Medicine, KU Leuven; VIB Center for Brain and Disease Research, Leuven, Belgium
| | - Robbe Naert
- Laboratory of Ion Channel Research, Department of Cellular and Molecular Medicine, KU Leuven; VIB Center for Brain and Disease Research, Leuven, Belgium
| | - Bernd Nilius
- Laboratory of Ion Channel Research, Department of Cellular and Molecular Medicine, KU Leuven; VIB Center for Brain and Disease Research, Leuven, Belgium
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21
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Non-Analgesic Symptomatic or Disease-Modifying Potential of TRPA1. Med Sci (Basel) 2019; 7:medsci7100099. [PMID: 31547502 PMCID: PMC6836032 DOI: 10.3390/medsci7100099] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Revised: 09/18/2019] [Accepted: 09/19/2019] [Indexed: 02/07/2023] Open
Abstract
TRPA1, a versatile ion channel of the Transient Receptor Potential (TRP) channel family, detects a large variety of chemicals and can contribute to signal processing of other stimuli, e.g., due to its sensitivity to cytosolic calcium elevation or phosphoinositolphosphate modulation. At first, TRPA1 was found on sensory neurons, where it can act as a sensor for potential or actual tissue damage that ultimately may elicit pain or itch as warning symptoms. This review provides an update regarding the analgesic and antipruritic potential of TRPA1 modulation and the respective clinical trials. Furthermore, TRPA1 has been found in an increasing amount of other cell types. Therefore, the main focus of the review is to discuss the non-analgesic and particularly the disease-modifying potential of TRPA1. This includes diseases of the respiratory system, cancer, ischemia, allergy, diabetes, and the gastrointestinal system. The involvement of TRPA1 in the respective pathophysiological cascades is so far mainly based on pre-clinical data.
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22
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Roles of ASICs in Nociception and Proprioception. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1099:37-47. [PMID: 30306513 DOI: 10.1007/978-981-13-1756-9_4] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Acid-sensing ion channels (ASICs) are a group of proton-gated ion channels belonging to the degenerin/epithelial sodium channel (DED/ENaC) family. There are at least six ASIC subtypes - ASIC1a, ASIC1b, ASIC2a, ASIC2b, ASIC3, and ASIC4 - all expressed in somatosensory neurons. ASIC3 is the most abundant in dorsal root ganglia (DRG) and the most sensitive to extracellular acidification. ASICs were found as the major player involved in acid-induced pain in humans. Accumulating evidence has further shown ASIC3 as the molecular determinant involved in pain-associated tissue acidosis in rodent models. Besides having a role in nociception, members of the DEG/ENaC family have been demonstrated as essential mechanotransducers in the nematode Caenorhabditis elegans and fly Drosophila melanogaster. ASICs are mammalian homologues of DEG/ENaC and therefore may play a role in mechanotransduction. However, the role of ASICs in neurosensory mechanotransduction is disputed. Here we review recent studies to probe the roles of ASICs in acid nociception and neurosensory mechanotransduction. In reviewing genetic models and delicate electrophysiology approaches, we show ASIC3 as a dual-function protein for both acid-sensing and mechano-sensing in somatosensory nerves and therefore involved in regulating both nociception and proprioception.
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Giorgi S, Nikolaeva-Koleva M, Alarcón-Alarcón D, Butrón L, González-Rodríguez S. Is TRPA1 Burning Down TRPV1 as Druggable Target for the Treatment of Chronic Pain? Int J Mol Sci 2019; 20:ijms20122906. [PMID: 31197115 PMCID: PMC6627658 DOI: 10.3390/ijms20122906] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Revised: 06/12/2019] [Accepted: 06/13/2019] [Indexed: 12/14/2022] Open
Abstract
Over the last decades, a great array of molecular mediators have been identified as potential targets for the treatment of chronic pain. Among these mediators, transient receptor potential (TRP) channel superfamily members have been thoroughly studied. Namely, the nonselective cationic channel, transient receptor potential ankyrin subtype 1 (TRPA1), has been described as a chemical nocisensor involved in noxious cold and mechanical sensation and as rivalling TRPV1, which traditionally has been considered as the most important TRP channel involved in nociceptive transduction. However, few TRPA1-related drugs have succeeded in clinical trials. In the present review, we attempt to discuss the latest data on the topic and future directions for pharmacological intervention.
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Affiliation(s)
- Simona Giorgi
- Instituto de Investigación, Desarrollo e Innovación en Biotecnología Sanitaria de Elche (IDiBE), Avda de la Univesidad s/n, Universidad Miguel Hernández, 03202 Elche, Spain.
| | - Magdalena Nikolaeva-Koleva
- Instituto de Investigación, Desarrollo e Innovación en Biotecnología Sanitaria de Elche (IDiBE), Avda de la Univesidad s/n, Universidad Miguel Hernández, 03202 Elche, Spain.
- AntalGenics, SL. Ed. Quorum III, Parque Científico Universidad Miguel Hernández, Avda de la Universidad s/n, 03202 Elche, Spain.
| | - David Alarcón-Alarcón
- Instituto de Investigación, Desarrollo e Innovación en Biotecnología Sanitaria de Elche (IDiBE), Avda de la Univesidad s/n, Universidad Miguel Hernández, 03202 Elche, Spain.
| | - Laura Butrón
- Instituto de Investigación, Desarrollo e Innovación en Biotecnología Sanitaria de Elche (IDiBE), Avda de la Univesidad s/n, Universidad Miguel Hernández, 03202 Elche, Spain.
| | - Sara González-Rodríguez
- Instituto de Investigación, Desarrollo e Innovación en Biotecnología Sanitaria de Elche (IDiBE), Avda de la Univesidad s/n, Universidad Miguel Hernández, 03202 Elche, Spain.
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24
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A Human TRPA1-Specific Pain Model. J Neurosci 2019; 39:3845-3855. [PMID: 30862667 DOI: 10.1523/jneurosci.3048-18.2019] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Revised: 02/19/2019] [Accepted: 02/22/2019] [Indexed: 12/31/2022] Open
Abstract
The cation channel transient receptor potential ankyrin 1 (TRPA1) plays an important role in sensing potentially hazardous substances. However, TRPA1 species differences are substantial and limit translational research. TRPA1 agonists tested previously in humans also have other targets. Therefore, the sensation generated by isolated TRPA1 activation in humans is unknown. The availability of 2-chloro-N-(4-(4-methoxyphenyl)thiazol-2-yl)-N-(3-methoxypropyl)-acetamide (JT010), a potent and specific TRPA1 agonist, allowed us to explore this issue. To corroborate the specificity of JT010, it was investigated whether the TRPA1 antagonist (1E,3E)-1-(4-fluorophenyl)-2-methyl-1-penten-3-one oxime (A-967079) abolishes JT010-elicited pain. Sixteen healthy volunteers of both sexes rated pain due to intraepidermal injections of different concentrations and combinations of the substances. The study design was a double-blind crossover study. All subjects received all types of injections, including a placebo without substances. Injections of the TRPA1 agonist dose-dependently caused pain with a half-maximal effective concentration of 0.31 μm Coinjection of A-967079 dose-dependently reduced and at a high concentration abolished JT010-induced pain. Quantification of JT010 by HPLC showed that a substantial part is adsorbed when in contact with polypropylene surfaces, but that this was overcome by handling in glass vials and injection using glass syringes. Isolated TRPA1 activation in humans causes pain. Thus, intradermal JT010 injection can serve as a tool to validate new TRPA1 antagonists concerning target engagement. More importantly, TRPA1-specific tools allow quantification of the TRPA1-dependent component in physiology and pathophysiology.SIGNIFICANCE STATEMENT This study showed that activation of the ion channel transient receptor potential ankyrin 1 (TRPA1) alone indeed suffices to elicit pain in humans, independent of other receptors previously found to be involved in pain generation. The newly established TRPA1-specific pain model allows different applications. First, it can be tested whether diseases are associated with compromised or exaggerated TRPA1-dependent painful sensations in the skin. Second, it can be investigated whether a new, possibly systemically applied drug directed against TRPA1 engages its target in humans. Further, the general possibility of quantitative inhibition of TRPA1 allows identification of the TRPA1-dependent disease component, given that the substance reaches its target. This contributes to a better understanding of pathophysiology, can lay the basis for new therapeutic approaches, and can bridge the gap between preclinical research and clinical trials.
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NF-κB-Associated Pain-Related Neuropeptide Expression in Patients with Degenerative Disc Disease. Int J Mol Sci 2019; 20:ijms20030658. [PMID: 30717434 PMCID: PMC6386867 DOI: 10.3390/ijms20030658] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2019] [Revised: 01/30/2019] [Accepted: 01/30/2019] [Indexed: 12/14/2022] Open
Abstract
The role of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) has been highlighted in mechanisms underlying inflammatory and neuropathic pain processes. The present study was designed to investigate whether NF-κB signaling is associated with pain-related neuropeptide expression in patients with chronic back pain related to degenerative disc disease (DDD). Intervertebral disc (IVD) tissues were collected from forty DDD patients undergoing disc replacement or fusion surgery, and from eighteen postmortem (PM) control subjects. RELA, NFKB1, CGRP, TAC1, TRPV1, and MMP-3 gene expression were analyzed by RT-qPCR, while NF-κB subunit RelA and NF-κB1⁻DNA binding in nuclear extracts and calcitonin gene related peptide (CGRP), substance P (SP), and transient receptor potential, subfamily V, member 1 (TRPV1) protein levels in cytosolic extracts of tissues were assessed by enzyme-linked immunosorbent assay (ELISA). An upregulated NF-κB1⁻DNA binding, and higher CGRP and TRPV1 protein levels were observed in DDD patients compared to PM controls. In DDD patients, NF-κB1⁻DNA binding was positively correlated with nuclear RelA levels. Moreover, NF-κB1⁻DNA binding was positively associated with TRPV1 and MMP-3 gene and SP and TRPV1 protein expression in DDD patients. Our results indicate that the expression of SP and TRPV1 in IVD tissues was associated with NF-κB activation. Moreover, NF-κB may be involved in the generation or maintenance of peripheral pain mechanisms by the regulation of pain-related neuropeptide expression in DDD patients.
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Wang XL, Cui LW, Liu Z, Gao YM, Wang S, Li H, Liu HX, Yu LJ. Effects of TRPA1 activation and inhibition on TRPA1 and CGRP expression in dorsal root ganglion neurons. Neural Regen Res 2019; 14:140-148. [PMID: 30531088 PMCID: PMC6262987 DOI: 10.4103/1673-5374.243719] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Transient receptor potential ankyrin 1 (TRPA1) is a key player in pain and neurogenic inflammation, and is localized in nociceptive primary sensory dorsal root ganglion (DRG) neurons. TRPA1 plays a major role in the transmission of nociceptive sensory signals. The generation of neurogenic inflammation appears to involve TRPA1-evoked release of calcitonin gene-related peptide (CGRP). However, it remains unknown whether TRPA1 or CGRP expression is affected by TRPA1 activation. Thus, in this study, we examined TRPA1 and CGRP expression in DRG neurons in vitro after treatment with the TRPA1 activator formaldehyde or the TRPA1 blocker menthol. In addition, we examined the role of extracellular signal-regulated protein kinase 1/2 (ERK1/2) in this process. DRG neurons in culture were exposed to formaldehyde, menthol, the ERK1/2 inhibitor PD98059 + formaldehyde, or PD98059 + menthol. After treatment, real-time polymerase chain reaction, western blot assay and double immunofluorescence labeling were performed to evaluate TRPA1 and CGRP expression in DRG neurons. Formaldehyde elevated mRNA and protein levels of TRPA1 and CGRP, as well as the proportion of TRPA1- and CGRP-positive neurons. In contrast, menthol reduced TRPA1 and CGRP expression. Furthermore, the effects of formaldehyde, but not menthol, on CGRP expression were blocked by pretreatment with PD98059. PD98059 pretreatment did not affect TRPA1 expression in the presence of formaldehyde or menthol.
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Affiliation(s)
- Xiao-Lei Wang
- Department of Rheumatology, Qilu Hospital of Shandong University, Jinan, Shandong Province, China
| | - Li-Wei Cui
- Department of Respiratory Medicine, Qilu Hospital of Shandong University, Jinan, Shandong Province, China
| | - Zhen Liu
- Department of Rheumatology, Qilu Hospital of Shandong University, Jinan, Shandong Province, China
| | - Yue-Ming Gao
- Department of Rheumatology, Qilu Hospital of Shandong University, Jinan, Shandong Province, China
| | - Sheng Wang
- Department of Rheumatology, Qilu Hospital of Shandong University, Jinan, Shandong Province, China
| | - Hao Li
- Department of Orthopedics, Qilu Hospital of Shandong University, Jinan, Shandong Province, China
| | - Hu-Xiang Liu
- Department of Rheumatology, Qilu Hospital of Shandong University, Jinan, Shandong Province, China
| | - Ling-Jia Yu
- Department of Rheumatology, Qilu Hospital of Shandong University, Jinan, Shandong Province, China
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Lin JH, Hung CH, Han DS, Chen ST, Lee CH, Sun WZ, Chen CC. Sensing acidosis: nociception or sngception? J Biomed Sci 2018; 25:85. [PMID: 30486810 PMCID: PMC6263053 DOI: 10.1186/s12929-018-0486-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Accepted: 11/09/2018] [Indexed: 12/19/2022] Open
Abstract
Background Sensing tissue acidosis is an important function of the somatosensory nervous system to response to noxious stimuli. Main body In the pain clinic, acid or soreness sensation is a characteristic sensory phenotype of various acute and chronic pain syndromes, such as delayed onset muscle soreness, fibromyalgia, and radicular pain. However, soreness sensation is a sign of successful analgesia for acupuncture and noxipoint therapy. Thus, the nature of acid or soreness sensation is not always nociceptive (or painful) and could be anti-nociceptive. To facilitate the investigation of the molecular and neurobiological mechanisms of soreness sensation, we propose a concept called “sngception (sng- ception)” to describe the response of the somatosensory nervous system to sense tissue acidosis and to distinguish it from nociception. “Sng” is a Taiwanese word that represents the state of soreness while at the same time imitates the natural vocalization of humans feeling sore. Conclusion Here we propose sngception as a specific somatosensory function that transmits the acid sensation from the peripheral to the central nervous system. Sngception could partially overlap with nociception, but it could also transmit antinociception, proprioception, and pruriception.
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Affiliation(s)
- Jiann-Her Lin
- Institute of Biomedical Sciences, Academia Sinica, 128 Academia Rd. Sec. 2, Taipei, 115, Taiwan.,Department of Neurosurgery, Taipei Medical University Hospital, Taipei, Taiwan
| | - Chih-Hsien Hung
- Institute of Biomedical Sciences, Academia Sinica, 128 Academia Rd. Sec. 2, Taipei, 115, Taiwan.,Department of Neurology, Kaohsiung Medical University Hospital; Kaohsiung Medical University, Kaohsiung, Taiwan.,PhD program in Translational Medicine, Kaohsiung Medical University and Academia Sinica, Taipei, Taiwan
| | - Der-Sheng Han
- Department of Physical Medicine and Rehabilitation, National Taiwan University Hospital, Bei-Hu Branch, Taipei, Taiwan
| | - Shih-Ting Chen
- Institute of Biomedical Sciences, Academia Sinica, 128 Academia Rd. Sec. 2, Taipei, 115, Taiwan
| | - Cheng-Han Lee
- Institute of Biomedical Sciences, Academia Sinica, 128 Academia Rd. Sec. 2, Taipei, 115, Taiwan
| | - Wei-Zen Sun
- Department of Anesthesiology, National Taiwan University Hospital, Taipei, Taiwan.
| | - Chih-Cheng Chen
- Institute of Biomedical Sciences, Academia Sinica, 128 Academia Rd. Sec. 2, Taipei, 115, Taiwan. .,PhD program in Translational Medicine, Kaohsiung Medical University and Academia Sinica, Taipei, Taiwan. .,Taiwan Mouse Clinic - National Comprehensive Mouse Phenotyping and Drug Testing Center, Academia Sinica, Taipei, Taiwan.
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28
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Lorusso L, Salerno M, Sessa F, Nicolosi D, Longhitano L, Loreto C, Carotenuto M, Messina A, Monda V, Villano I, Cibelli G, Valenzano A, Monda M, Murabito P, Mollica MP, Messina G, Viggiano A. Autoalgometry: An Important Tool for Pressure Pain Threshold Evaluation. J Clin Med 2018; 7:jcm7090273. [PMID: 30213091 PMCID: PMC6162811 DOI: 10.3390/jcm7090273] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Revised: 09/07/2018] [Accepted: 09/10/2018] [Indexed: 11/16/2022] Open
Abstract
The term "pain threshold" refers to the measurement of the intensity of a physical stimulus that evokes pain. To estimate the pain threshold, a mechanical or electrical stimulus with increasing intensity is usually applied until the subject under evaluation refers to a pain sensation. This study aims to evaluate the autoalgometric pain threshold as a perfect technique to determine the effects of stimulation rate in relation to both gender and the site of stimulation. In this experimental model, pressure algometry was applied: the subject under evaluation pushed a finger against a small round metal tip, producing and at the same time controlling the intensity of the noxious stimulus. Through autoalgometry, the stimulus intensity was recorded over time, measuring the force change rate applied and studying the subject's behavior on approaching pain. This test was performed with 50 healthy volunteers on two days, applying a fast or slow rate of stimulation. The results described demonstrate that there is a positive correlation between the pressure increase rate and the pressure threshold evaluation. In light of these findings, autoalgometry can be proposed as an objective measure of pressure pain threshold for clinical and research use.
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Affiliation(s)
- Letizia Lorusso
- Department of Medicine, Surgery and Dentistry "Scuola Medica Salernitana", University of Salerno, 84081 Baronissi, Italy.
| | - Monica Salerno
- Department of Clinical and Experimental Medicine, University of Foggia, 71122 Foggia, Italy.
| | - Francesco Sessa
- Department of Clinical and Experimental Medicine, University of Foggia, 71122 Foggia, Italy.
| | - Daniela Nicolosi
- Department of Biomedical and Biotechnological Sciences, University of Catania, 95131 Catania, Italy.
| | - Lucia Longhitano
- Department of Biomedical and Biotechnological Sciences, University of Catania, 95131 Catania, Italy.
| | - Carla Loreto
- Department of Biomedical and Biotechnological Sciences, University of Catania, 95131 Catania, Italy.
| | - Marco Carotenuto
- Clinic of Child and Adolescent Neuropsychiatry, Department of Mental Health, Physical and Preventive Medicine, University of Campania "Luigi Vanvitelli", 80138 Naples, Italy.
| | - Antonietta Messina
- Department of Experimental Medicine, Section of Human Physiology and Unit of Dietetic and Sport Medicine, University of Campania "Luigi Vanvitelli", 80138 Naples, Italy.
| | - Vincenzo Monda
- Department of Experimental Medicine, Section of Human Physiology and Unit of Dietetic and Sport Medicine, University of Campania "Luigi Vanvitelli", 80138 Naples, Italy.
| | - Ines Villano
- Department of Experimental Medicine, Section of Human Physiology and Unit of Dietetic and Sport Medicine, University of Campania "Luigi Vanvitelli", 80138 Naples, Italy.
| | - Giuseppe Cibelli
- Department of Clinical and Experimental Medicine, University of Foggia, 71122 Foggia, Italy.
| | - Anna Valenzano
- Department of Clinical and Experimental Medicine, University of Foggia, 71122 Foggia, Italy.
| | - Marcellino Monda
- Department of Experimental Medicine, Section of Human Physiology and Unit of Dietetic and Sport Medicine, University of Campania "Luigi Vanvitelli", 80138 Naples, Italy.
| | - Paolo Murabito
- Department of Surgery and Surgical Medical Specialties, University of Catania, 95131 Catania, Italy.
| | - Maria Pina Mollica
- Department of Biology, University of Naples Federico II, 80138 Naples, Italy.
| | - Giovanni Messina
- Department of Clinical and Experimental Medicine, University of Foggia, 71122 Foggia, Italy.
| | - Andrea Viggiano
- Department of Medicine, Surgery and Dentistry "Scuola Medica Salernitana", University of Salerno, 84081 Baronissi, Italy.
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29
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Bräunig J, Mergler S, Jyrch S, Hoefig CS, Rosowski M, Mittag J, Biebermann H, Khajavi N. 3-Iodothyronamine Activates a Set of Membrane Proteins in Murine Hypothalamic Cell Lines. Front Endocrinol (Lausanne) 2018; 9:523. [PMID: 30298050 PMCID: PMC6161562 DOI: 10.3389/fendo.2018.00523] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Accepted: 08/21/2018] [Indexed: 01/26/2023] Open
Abstract
3-Iodothyronamine (3-T1AM) is an endogenous thyroid hormone metabolite. The profound pharmacological effects of 3-T1AM on energy metabolism and thermal homeostasis have raised interest to elucidate its signaling properties in tissues that pertain to metabolic regulation and thermogenesis. Previous studies identified G protein-coupled receptors (GPCRs) and transient receptor potential channels (TRPs) as targets of 3-T1AM in different cell types. These two superfamilies of membrane proteins are largely expressed in tissue which influences energy balance and metabolism. As the first indication that 3-T1AM virtually modulates the function of the neurons in hypothalamus, we observed that intraperitoneal administration of 50 mg/kg bodyweight of 3-T1AM significantly increased the c-FOS activation in the paraventricular nucleus (PVN) of C57BL/6 mice. To elucidate the underlying mechanism behind this 3-T1AM-induced signalosome, we used three different murine hypothalamic cell lines, which are all known to express PVN markers, GT1-7, mHypoE-N39 (N39) and mHypoE-N41 (N41). Various aminergic GPCRs, which are the known targets of 3-T1AM, as well as numerous members of TRP channel superfamily, are expressed in these cell lines. Effects of 3-T1AM on activation of GPCRs were tested for the two major signaling pathways, the action of Gαs/adenylyl cyclase and Gi/o. Here, we demonstrated that this thyroid hormone metabolite has no significant effect on Gi/o signaling and only a minor effect on the Gαs/adenylyl cyclase pathway, despite the expression of known GPCR targets of 3-T1AM. Next, to test for other potential mechanisms involved in 3-T1AM-induced c-FOS activation in PVN, we evaluated the effect of 3-T1AM on the intracellular Ca2+ concentration and whole-cell currents. The fluorescence-optic measurements showed a significant increase of intracellular Ca2+ concentration in the three cell lines in the presence of 10 μM 3-T1AM. Furthermore, this thyroid hormone metabolite led to an increase of whole-cell currents in N41 cells. Interestingly, the TRPM8 selective inhibitor (10 μM AMTB) reduced the 3-T1AM stimulatory effects on cytosolic Ca2+ and whole-cell currents. Our results suggest that the profound pharmacological effects of 3-T1AM on selected brain nuclei of murine hypothalamus, which are known to be involved in energy metabolism and thermoregulation, might be partially attributable to TRP channel activation in hypothalamic cells.
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Affiliation(s)
- Julia Bräunig
- Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
- Institute of Experimental Pediatric Endocrinology, Berlin, Germany
| | - Stefan Mergler
- Klinik für Augenheilkunde, Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Sabine Jyrch
- Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
- Institute of Experimental Pediatric Endocrinology, Berlin, Germany
| | - Carolin S. Hoefig
- Institute of Experimental Endocrinology, Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
- Department of Cell & Molecular Biology, Karolinska Instituet, Stockholm, Sweden
| | - Mark Rosowski
- Department Medical Biotechnology, Institute of Biotechnology, Technical University of Berlin, Berlin, Germany
| | - Jens Mittag
- Department of Cell & Molecular Biology, Karolinska Instituet, Stockholm, Sweden
- University of Lübeck – Center of Brain Behavior and Metabolism, Lübeck, Germany
| | - Heike Biebermann
- Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
- Institute of Experimental Pediatric Endocrinology, Berlin, Germany
| | - Noushafarin Khajavi
- Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
- Institute of Experimental Pediatric Endocrinology, Berlin, Germany
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30
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Wright AJ, Husson ZM, Hu D, Callejo G, Brindle KM, Smith ESJ. Increased hyperpolarized [1- 13 C] lactate production in a model of joint inflammation is not accompanied by tissue acidosis as assessed using hyperpolarized 13 C-labelled bicarbonate. NMR IN BIOMEDICINE 2018; 31:e3892. [PMID: 29380927 PMCID: PMC5887936 DOI: 10.1002/nbm.3892] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Revised: 12/01/2017] [Accepted: 12/07/2017] [Indexed: 05/11/2023]
Abstract
Arthritic conditions are a major source of chronic pain. Furthering our understanding of disease mechanisms creates the opportunity to develop more targeted therapeutics. In rheumatoid arthritis (RA), measurements of pH in human synovial fluid suggest that acidosis occurs, but that this is highly variable between individuals. Here we sought to determine if tissue acidosis occurs in a widely used rodent arthritis model: complete Freund's adjuvant (CFA)-induced inflammation. CFA robustly evoked paw and ankle swelling, concomitant with worsening clinical scores over time. We used magnetic resonance spectroscopic imaging of hyperpolarized [1-13 C]pyruvate metabolism to demonstrate that CFA induces an increase in the lactate-to-pyruvate ratio. This increase is indicative of enhanced glycolysis and an increased lactate concentration, as has been observed in the synovial fluid from RA patients, and which was correlated with acidosis. We also measured the 13 CO2 /H13 CO3- ratio, in animals injected with hyperpolarized H13 CO3- , to estimate extracellular tissue pH and showed that despite the apparent increase in glycolytic activity in CFA-induced inflammation there was no accompanying decrease in extracellular pH. The pH was 7.23 ± 0.06 in control paws and 7.32 ± 0.09 in inflamed paws. These results could explain why mice lacking acid-sensing ion channel subunits 1, 2 and 3 do not display any changes in mechanical or thermal hyperalgesia in CFA-induced inflammation.
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Affiliation(s)
- Alan J. Wright
- Cancer Research UK Cambridge InstituteUniversity of Cambridge, Li Ka Shing Centre, Robinson WayCambridgeUK
| | - Zoé M.A. Husson
- Department of PharmacologyUniversity of Cambridge, Tennis Court RoadCambridgeUK
| | - De‐En Hu
- Cancer Research UK Cambridge InstituteUniversity of Cambridge, Li Ka Shing Centre, Robinson WayCambridgeUK
| | - Gerard Callejo
- Department of PharmacologyUniversity of Cambridge, Tennis Court RoadCambridgeUK
| | - Kevin M. Brindle
- Cancer Research UK Cambridge InstituteUniversity of Cambridge, Li Ka Shing Centre, Robinson WayCambridgeUK
- Department of BiochemistryUniversity of Cambridge, Tennis Court RoadCambridgeUK
| | - Ewan St. John Smith
- Department of PharmacologyUniversity of Cambridge, Tennis Court RoadCambridgeUK
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31
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Moore C, Gupta R, Jordt SE, Chen Y, Liedtke WB. Regulation of Pain and Itch by TRP Channels. Neurosci Bull 2018; 34:120-142. [PMID: 29282613 PMCID: PMC5799130 DOI: 10.1007/s12264-017-0200-8] [Citation(s) in RCA: 191] [Impact Index Per Article: 31.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Accepted: 10/27/2017] [Indexed: 02/07/2023] Open
Abstract
Nociception is an important physiological process that detects harmful signals and results in pain perception. In this review, we discuss important experimental evidence involving some TRP ion channels as molecular sensors of chemical, thermal, and mechanical noxious stimuli to evoke the pain and itch sensations. Among them are the TRPA1 channel, members of the vanilloid subfamily (TRPV1, TRPV3, and TRPV4), and finally members of the melastatin group (TRPM2, TRPM3, and TRPM8). Given that pain and itch are pro-survival, evolutionarily-honed protective mechanisms, care has to be exercised when developing inhibitory/modulatory compounds targeting specific pain/itch-TRPs so that physiological protective mechanisms are not disabled to a degree that stimulus-mediated injury can occur. Such events have impeded the development of safe and effective TRPV1-modulating compounds and have diverted substantial resources. A beneficial outcome can be readily accomplished via simple dosing strategies, and also by incorporating medicinal chemistry design features during compound design and synthesis. Beyond clinical use, where compounds that target more than one channel might have a place and possibly have advantageous features, highly specific and high-potency compounds will be helpful in mechanistic discovery at the structure-function level.
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Affiliation(s)
- Carlene Moore
- Department of Neurology, Duke University Medical Center, Durham, NC, 27710, USA
| | - Rupali Gupta
- Department of Neurology, Duke University Medical Center, Durham, NC, 27710, USA
| | - Sven-Eric Jordt
- Department of Anesthesiology, Duke University Medical Center, Durham, NC, 27710, USA
| | - Yong Chen
- Department of Neurology, Duke University Medical Center, Durham, NC, 27710, USA.
| | - Wolfgang B Liedtke
- Department of Neurology, Duke University Medical Center, Durham, NC, 27710, USA.
- Department of Anesthesiology, Duke University Medical Center, Durham, NC, 27710, USA.
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32
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Lee JYP, Saez NJ, Cristofori-Armstrong B, Anangi R, King GF, Smith MT, Rash LD. Inhibition of acid-sensing ion channels by diminazene and APETx2 evoke partial and highly variable antihyperalgesia in a rat model of inflammatory pain. Br J Pharmacol 2018; 175:2204-2218. [PMID: 29134638 DOI: 10.1111/bph.14089] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2017] [Revised: 10/22/2017] [Accepted: 10/31/2017] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND AND PURPOSE Acid-sensing ion channels (ASICs) are primary acid sensors in mammals, with the ASIC1b and ASIC3 subtypes being involved in peripheral nociception. The antiprotozoal drug diminazene is a moderately potent ASIC inhibitor, but its analgesic activity has not been assessed. EXPERIMENTAL APPROACH We determined the ASIC subtype selectivity of diminazene and the mechanism by which it inhibits ASICs using voltage-clamp electrophysiology of Xenopus oocytes expressing ASICs 1-3. Its peripheral analgesic activity was then assessed relative to APETx2, an ASIC3 inhibitor, and morphine, in a Freund's complete adjuvant (FCA)-induced rat model of inflammatory pain. KEY RESULTS Diminazene inhibited homomeric rat ASICs with IC50 values of ~200-800 nM, via an open channel and subtype-dependent mechanism. In rats with FCA-induced inflammatory pain in one hindpaw, diminazene and APETx2 evoked more potent peripheral antihyperalgesia than morphine, but the effect was partial for APETx2. APETx2 potentiated rat ASIC1b at concentrations 30-fold to 100-fold higher than the concentration inhibiting ASIC3, which may have implications for its use in in vivo experiments. CONCLUSIONS AND IMPLICATIONS Diminazene and APETx2 are moderately potent ASIC inhibitors, both inducing peripheral antihyperalgesia in a rat model of chronic inflammatory pain. APETx2 has a more complex ASIC pharmacology, which must be considered when it is used as a supposedly selective ASIC3 inhibitor in vivo. Our use of outbred rats revealed responders and non-responders when ASIC inhibition was used to alleviate inflammatory pain, which is aligned with the concept of number-needed-to-treat in human clinical studies. LINKED ARTICLES This article is part of a themed section on Recent Advances in Targeting Ion Channels to Treat Chronic Pain. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v175.12/issuetoc.
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Affiliation(s)
- Jia Yu Peppermint Lee
- UQ Centre for Clinical Research, Faculty of Medicine, The University of Queensland, St Lucia, QLD, Australia
| | - Natalie J Saez
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD, Australia
| | | | - Raveendra Anangi
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD, Australia
| | - Glenn F King
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD, Australia
| | - Maree T Smith
- UQ Centre for Clinical Research, Faculty of Medicine, The University of Queensland, St Lucia, QLD, Australia.,School of Pharmacy, The University of Queensland, St Lucia, QLD, Australia
| | - Lachlan D Rash
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, QLD, Australia.,School of Biomedical Sciences, The University of Queensland, St Lucia, QLD, Australia
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33
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Translational Model Systems for Complex Sodium Channel Pathophysiology in Pain. Handb Exp Pharmacol 2018; 246:355-369. [PMID: 29374838 DOI: 10.1007/164_2017_91] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
Chronic pain patients are often left with insufficient treatment as the pathophysiology especially of neuropathic pain remains enigmatic. Recently, genetic variations in the genes of the voltage-gated sodium channels (Navs) were linked to inherited neuropathic pain syndromes, opening a research pathway to foster our understanding of the pathophysiology of neuropathic pain. More than 10 years ago, the rare, inherited pain syndrome erythromelalgia was linked to mutations in the subtype Nav1.7, and since then a plethora of mutations and genetic variations in this and other Nav genes were identified. Often the biophysical changes induced by the genetic alteration offer a straightforward explanation for the clinical symptoms, but mutations in some channels, especially Nav1.9, paint a more complex picture. Although efforts were undertaken to significantly advance our knowledge, translation from heterologous or animal model systems to humans remains a challenge. Here we present recent advances in translation using stem cell-derived human sensory neurons and their potential application for identification of better, effective, and more precise treatment for the individual pain patient.
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34
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Wu J, Wang JJ, Liu TT, Zhou YM, Qiu CY, Shen DW, Hu WP. PPAR-α acutely inhibits functional activity of ASICs in rat dorsal root ganglion neurons. Oncotarget 2017; 8:93051-93062. [PMID: 29190977 PMCID: PMC5696243 DOI: 10.18632/oncotarget.21805] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Accepted: 08/29/2017] [Indexed: 12/29/2022] Open
Abstract
Peroxisome proliferator-activated receptor-α (PPAR-α), a lipid activated transcription factor of nuclear hormone receptor superfamily, can relieve pain through a rapid-response mechanism. However, little is known about the underlying mechanism. Herein, we report that PPAR-α activation acutely inhibits the functional activity of acid-sensing ion channels (ASICs), key sensors for extracellular protons, in rat dorsal root ganglion (DRG) neurons. Pre-application of PPAR-α agonist GW7647 for 2 min decreased the amplitude of proton-gated currents mediated by ASICs in a concentration-dependent manner. GW7647 shifted the concentration-response curve for proton downwards, with a decrease of 36.9 ± 2.3% in the maximal current response to proton. GW7647 inhibition of proton-gated currents can be blocked by GW6471, a selective PPAR-α antagonist. Moreover, PPAR-α activation decreased the number of acidosis-evoked action potentials in rat DRG neurons. Finally, peripheral administration of GW7647 dose-dependently relieved nociceptive responses to injection of acetic acid in rats. These results indicated that activation of peripheral PPAR-α acutely inhibited functional activity of ASICs in a non-genomic manner, which revealed a novel mechanism underlying rapid analgesia through peripheral PPAR-α.
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Affiliation(s)
- Jing Wu
- Research Center of Basic Medical Sciences, School of Basic Medical Sciences, Hubei University of Science and Technology, Xianning 437100, Hubei, P.R. China
| | - Jia-Jia Wang
- Research Center of Basic Medical Sciences, School of Basic Medical Sciences, Hubei University of Science and Technology, Xianning 437100, Hubei, P.R. China
| | - Ting-Ting Liu
- Research Center of Basic Medical Sciences, School of Basic Medical Sciences, Hubei University of Science and Technology, Xianning 437100, Hubei, P.R. China.,Department of Physiology, School of Basic Medical Sciences, Hubei University of Science and Technology, Xianning 437100, Hubei, P.R. China
| | - Yi-Mei Zhou
- Research Center of Basic Medical Sciences, School of Basic Medical Sciences, Hubei University of Science and Technology, Xianning 437100, Hubei, P.R. China
| | - Chun-Yu Qiu
- Department of Pharmacology, Hubei University of Science and Technology, Xianning 437100, Hubei, P.R. China
| | - Ding-Wen Shen
- Research Center of Basic Medical Sciences, School of Basic Medical Sciences, Hubei University of Science and Technology, Xianning 437100, Hubei, P.R. China
| | - Wang-Ping Hu
- Research Center of Basic Medical Sciences, School of Basic Medical Sciences, Hubei University of Science and Technology, Xianning 437100, Hubei, P.R. China.,Department of Physiology, School of Basic Medical Sciences, Hubei University of Science and Technology, Xianning 437100, Hubei, P.R. China
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