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Sánchez-Hernández R, Benítez-Angeles M, Hernández-Vega AM, Rosenbaum T. Recent advances on the structure and the function relationships of the TRPV4 ion channel. Channels (Austin) 2024; 18:2313323. [PMID: 38354101 PMCID: PMC10868539 DOI: 10.1080/19336950.2024.2313323] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Accepted: 01/18/2024] [Indexed: 02/16/2024] Open
Abstract
The members of the superfamily of Transient Receptor Potential (TRP) ion channels are physiologically important molecules that have been studied for many years and are still being intensively researched. Among the vanilloid TRP subfamily, the TRPV4 ion channel is an interesting protein due to its involvement in several essential physiological processes and in the development of various diseases. As in other proteins, changes in its function that lead to the development of pathological states, have been closely associated with modification of its regulation by different molecules, but also by the appearance of mutations which affect the structure and gating of the channel. In the last few years, some structures for the TRPV4 channel have been solved. Due to the importance of this protein in physiology, here we discuss the recent progress in determining the structure of the TRPV4 channel, which has been achieved in three species of animals (Xenopus tropicalis, Mus musculus, and Homo sapiens), highlighting conserved features as well as key differences among them and emphasizing the binding sites for some ligands that play crucial roles in its regulation.
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Affiliation(s)
- Raúl Sánchez-Hernández
- Departamento de Neurociencia Cognitiva, División Neurociencias, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico, Mexico
| | - Miguel Benítez-Angeles
- Departamento de Neurociencia Cognitiva, División Neurociencias, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico, Mexico
| | - Ana M. Hernández-Vega
- Departamento de Neurociencia Cognitiva, División Neurociencias, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico, Mexico
| | - Tamara Rosenbaum
- Departamento de Neurociencia Cognitiva, División Neurociencias, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico, Mexico
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Zhang Y, Lu Q, Hu H, Yang C, Zhao Q. Esketamine alleviates hypoxia/reoxygenation injury of cardiomyocytes by regulating TRPV1 expression and inhibiting intracellular Ca 2+ concentration. Clinics (Sao Paulo) 2024; 79:100363. [PMID: 38692008 PMCID: PMC11070684 DOI: 10.1016/j.clinsp.2024.100363] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Accepted: 04/07/2024] [Indexed: 05/03/2024] Open
Abstract
OBJECTIVE This study aimed to investigate the effect of Esketamine (ESK) on the Hypoxia/Reoxygenation (H/R) injury of cardiomyocytes by regulating TRPV1 and inhibiting the concentration of intracellular Ca2+. METHODS The H/R injury model of H9c2 cardiomyocytes was established after 4h hypoxia and 6h reoxygenation. H9c2 cells were treated with different concentrations of ESK or TRPV1 agonist capsaicin (10 μM) or TRPV1 inhibitor capsazepine (1 μM). Cell viability was detected by CCK-8 method, and apoptosis by flow cytometry. Intracellular Ca2+ concentration was evaluated by Fluo-4 AM. LDH, MDA, SOD, and GSH-Px were detected with corresponding commercial kits. TRPV1 and p-TRPV1 proteins were detected by Western blot. RESULTS After H/R, H9c2 cell viability decreased, apoptosis increased, intracellular Ca2+ concentration increased, LDH and MDA levels increased, SOD and GSH-Px levels decreased, and p-TRPV1 expression increased. ESK treatment rescued these changes induced by H/R. After up-regulating TRPV1, the protective effect of ESK on H/R injury of H9c2 cells was weakened, while down-regulating TRPV1 could further protect against H/R injury. CONCLUSION ESK alleviates H/R injury of cardiomyocytes by regulating TRPV1 expression and inhibiting intracellular Ca2+ concentration.
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Affiliation(s)
- Ying Zhang
- Department of Anesthesiology, The First Affiliated Hospital of Bengbu Medical College, Bengbu City, Anhui Province, China
| | - QuanMei Lu
- Department of Anesthesiology, The First Affiliated Hospital of Bengbu Medical College, Bengbu City, Anhui Province, China
| | - HanChun Hu
- Department of Anesthesiology, The First Affiliated Hospital of Bengbu Medical College, Bengbu City, Anhui Province, China
| | - ChunChen Yang
- Department of Anesthesiology, The First Affiliated Hospital of Bengbu Medical College, Bengbu City, Anhui Province, China
| | - QiHong Zhao
- Department of Anesthesiology, The Second Affiliated Hospital of Bengbu Medical College, Bengbu City, Anhui Province, China.
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Dewaker V, Sharma AR, Debnath U, Park ST, Kim HS. Insights from molecular dynamics simulations of TRPV1 channel modulators in pain. Drug Discov Today 2023; 28:103798. [PMID: 37838068 DOI: 10.1016/j.drudis.2023.103798] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Revised: 09/28/2023] [Accepted: 10/09/2023] [Indexed: 10/16/2023]
Abstract
TRPV1 is a nonselective cation channel vital for detecting noxious stimuli (heat, acid, capsaicin). Its role in pain makes it a potential drug target for chronic pain management, migraines, and related disorders. This review updates molecular dynamics (MD) simulation studies on the TRPV1 channel, focusing on its gating mechanism, ligand-binding sites, and implications for drug design. The article also explores challenges in developing modulators, SAR optimization, and clinical trial studies. Efforts have been undertaken to concisely present MD simulation findings, with a focus on their relevance to drug discovery.
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Affiliation(s)
- Varun Dewaker
- Institute of New Frontier Research Team, Hallym University, Chuncheon-si 24252, Gangwon-do, Republic of Korea
| | - Ashish R Sharma
- Institute for Skeletal Aging & Orthopedic Surgery, Hallym University-Chuncheon Sacred Heart Hospital, Chuncheon-si 24252, Gangwon-do, Republic of Korea
| | - Utsab Debnath
- School of Health Sciences & Technology, UPES, Dehradun, Uttarakhand 248007, India
| | - Sung Taek Park
- Institute of New Frontier Research Team, Hallym University, Chuncheon-si 24252, Gangwon-do, Republic of Korea; Department of Obstetrics and Gynecology, Kangnam Sacred-Heart Hospital, Hallym University Medical Center, Hallym University College of Medicine, Seoul 07441, Republic of Korea; EIONCELL Inc., Chuncheon 24252, Republic of Korea
| | - Hyeong Su Kim
- Institute of New Frontier Research Team, Hallym University, Chuncheon-si 24252, Gangwon-do, Republic of Korea; Division of Hemato-Oncology, Department of Internal Medicine, Kangnam Sacred-Heart Hospital, Hallym University Medical Center, Hallym University College of Medicine, Seoul 07441, Republic of Korea; EIONCELL Inc., Chuncheon 24252, Republic of Korea.
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Li S, Zheng J. The capsaicin binding affinity of wildtype and mutant TRPV1 ion channels. J Biol Chem 2023; 299:105268. [PMID: 37734552 PMCID: PMC10616419 DOI: 10.1016/j.jbc.2023.105268] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Revised: 09/03/2023] [Accepted: 09/12/2023] [Indexed: 09/23/2023] Open
Abstract
Vanilloids such as capsaicin and resiniferatoxin are highly selective and potent activators for transient receptor potential vanilloid subfamily, member 1, a nociceptor for heat and pain perception. However, the intrinsic vanilloid binding affinity, key for understanding transient receptor potential vanilloid subfamily, member 1 function, remains unknown despite intensive investigations by electrophysiological, structural, and computational methods. In this study, we determined capsaicin binding affinity under physiological conditions by isolating individual binding steps to each subunit with concatemers. We estimated the capsaicin association constant of a wildtype subunit to be in the order of 106 M-1 and that of the Y511A mutant subunit to be a hundred times lower, in the order of 104 M-1. The Y511A mutation, located at the entrance of the vanilloid binding pocket, reduces binding affinity without a noticeable effect on activation gating. We further affirmed that there is little cooperativity between vanilloid binding steps. Models based on independent binding and equally cooperative subunit gating can accurately describe capsaicin activation.
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Affiliation(s)
- Shisheng Li
- Department of Physiology and Membrane Biology, University of California at Davis, School of Medicine, Davis California, USA
| | - Jie Zheng
- Department of Physiology and Membrane Biology, University of California at Davis, School of Medicine, Davis California, USA.
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Li S, Nguyen PT, Vu S, Yarov-Yarovoy V, Zheng J. Opening of capsaicin receptor TRPV1 is stabilized equally by its four subunits. J Biol Chem 2023; 299:104828. [PMID: 37196769 PMCID: PMC10318505 DOI: 10.1016/j.jbc.2023.104828] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2023] [Revised: 05/04/2023] [Accepted: 05/10/2023] [Indexed: 05/19/2023] Open
Abstract
Capsaicin receptor TRPV1 is a nociceptor for vanilloid molecules, such as capsaicin and resiniferatoxin (RTX). Even though cryo-EM structures of TRPV1 in complex with these molecules are available, how their binding energetically favors the open conformation is not known. Here, we report an approach to control the number of bound RTX molecules (0-4) in functional rat TRPV1. The approach allowed direct measurements of each of the intermediate open states under equilibrium conditions at both macroscopic and single-molecule levels. We found that RTX binding to each of the four subunits contributes virtually the same activation energy, which we estimated to be 1.70 to 1.86 kcal/mol and found to arise predominately from destabilizing the closed conformation. We further showed that sequential bindings of RTX increase open probability without altering single-channel conductance, confirming that there is likely a single open-pore conformation for TRPV1 activated by RTX.
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Affiliation(s)
- Shisheng Li
- Department of Physiology and Membrane Biology, School of Medicine, University of California at Davis, Davis, California, USA
| | - Phuong T Nguyen
- Department of Physiology and Membrane Biology, School of Medicine, University of California at Davis, Davis, California, USA
| | - Simon Vu
- Department of Physiology and Membrane Biology, School of Medicine, University of California at Davis, Davis, California, USA
| | - Vladimir Yarov-Yarovoy
- Department of Physiology and Membrane Biology, School of Medicine, University of California at Davis, Davis, California, USA
| | - Jie Zheng
- Department of Physiology and Membrane Biology, School of Medicine, University of California at Davis, Davis, California, USA.
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Otsuka Saito K, Fujita F, Toriyama M, Utami RA, Guo Z, Murakami M, Kato H, Suzuki Y, Okada F, Tominaga M, Ishii KJ. Roles of TRPM4 in immune responses in keratinocytes and identification of a novel TRPM4-activating agent. Biochem Biophys Res Commun 2023; 654:1-9. [PMID: 36871485 DOI: 10.1016/j.bbrc.2023.02.062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Revised: 02/13/2023] [Accepted: 02/22/2023] [Indexed: 03/06/2023]
Abstract
The skin is a protective interface between the internal organs and environment and functions not only as a physical barrier but also as an immune organ. However, the immune system in the skin is not fully understood. A member of the thermo-sensitive transient receptor potential (TRP) channel family, TRPM4, which acts as a regulatory receptor in immune cells, was recently reported to be expressed in human skin and keratinocytes. However, the function of TRPM4 in immune responses in keratinocytes has not been investigated. In this study, we found that treatment with BTP2, a known TRPM4 agonist, reduced cytokine production induced by tumor necrosis factor (TNF) α in normal human epidermal keratinocytes and in immortalized human epidermal keratinocytes (HaCaT cells). This cytokine-reducing effect was not observed in TRPM4-deficient HaCaT cells, indicating that TRPM4 contributed to the control of cytokine production in keratinocytes. Furthermore, we identified aluminum potassium sulfate, as a new TRPM4 activating agent. Aluminum potassium sulfate reduced Ca2+ influx by store-operated Ca2+ entry in human TRPM4-expressing HEK293T cells. We further confirmed that aluminum potassium sulfate evoked TRPM4-mediated currents, showing direct evidence for TRPM4 activation. Moreover, treatment with aluminum potassium sulfate reduced cytokine expression induced by TNFα in HaCaT cells. Taken together, our data suggested that TRPM4 may serve as a new target for the treatment of skin inflammatory reactions by suppressing the cytokine production in keratinocytes, and aluminum potassium sulfate is a useful ingredient to prevent undesirable skin inflammation through TRPM4 activation.
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Affiliation(s)
- Kaori Otsuka Saito
- Laboratory of Advanced Cosmetic Science, Graduate School of Pharmaceutical Sciences, Osaka University, 1-6, Yamadaoka, Suita, Osaka, 565-0871, Japan; Fundamental Research Institute, Mandom Corp., 5-12, Juniken-Cho, Chuo-ku, Osaka, 540-8530, Japan; Laboratory of Mock Up Vaccine, Center for Vaccine and Adjuvant Research (CVAR), National Institutes of Biomedical Innovation, Health and Nutrition (NBIOHN), 7-6-8, Asagi, Saito, Ibaraki-City, Osaka, 567-0085, Japan.
| | - Fumitaka Fujita
- Laboratory of Advanced Cosmetic Science, Graduate School of Pharmaceutical Sciences, Osaka University, 1-6, Yamadaoka, Suita, Osaka, 565-0871, Japan; Fundamental Research Institute, Mandom Corp., 5-12, Juniken-Cho, Chuo-ku, Osaka, 540-8530, Japan; Laboratory of Mock Up Vaccine, Center for Vaccine and Adjuvant Research (CVAR), National Institutes of Biomedical Innovation, Health and Nutrition (NBIOHN), 7-6-8, Asagi, Saito, Ibaraki-City, Osaka, 567-0085, Japan
| | - Manami Toriyama
- Laboratory of Advanced Cosmetic Science, Graduate School of Pharmaceutical Sciences, Osaka University, 1-6, Yamadaoka, Suita, Osaka, 565-0871, Japan; Laboratory of Mock Up Vaccine, Center for Vaccine and Adjuvant Research (CVAR), National Institutes of Biomedical Innovation, Health and Nutrition (NBIOHN), 7-6-8, Asagi, Saito, Ibaraki-City, Osaka, 567-0085, Japan; Graduate School of Science and Technology, Nara Institute of Science and Technology, 8916-5, Takayama-Cho, Ikoma, Nara, 630-0192, Japan
| | - Ratna Annisa Utami
- School of Pharmacy, Institut Teknologi Bandung, Jl. Ganesha No. 10, Bandung, 40132, Indonesia
| | - Zhihan Guo
- Laboratory of Advanced Cosmetic Science, Graduate School of Pharmaceutical Sciences, Osaka University, 1-6, Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Masato Murakami
- Laboratory of Advanced Cosmetic Science, Graduate School of Pharmaceutical Sciences, Osaka University, 1-6, Yamadaoka, Suita, Osaka, 565-0871, Japan; Technical Development Center, Mandom Corp., 5-12, Juniken-Cho, Chuo-ku, Osaka, 540-8530, Japan
| | - Hiroko Kato
- Laboratory of Advanced Cosmetic Science, Graduate School of Pharmaceutical Sciences, Osaka University, 1-6, Yamadaoka, Suita, Osaka, 565-0871, Japan; Laboratory of Mock Up Vaccine, Center for Vaccine and Adjuvant Research (CVAR), National Institutes of Biomedical Innovation, Health and Nutrition (NBIOHN), 7-6-8, Asagi, Saito, Ibaraki-City, Osaka, 567-0085, Japan
| | - Yoshiro Suzuki
- Thermal Biology Group, Exploratory Research Center on Life and Living Systems National Institutes of Natural Sciences, 5-1, Aza-higashiyama, Myodaiji, Okazaki, Aichi, 444-8787, Japan; Division of Cell Signaling, National Institute for Physiological Sciences, National Institutes of Natural Sciences, 5-1, Aza-higashiyama, Myodaiji, Okazaki, Aichi, 444-8787, Japan; Department of Physiological Sciences, SOKENDAI (The Graduate University for Advanced Studies), 5-1, Aza-higashiyama, Myodaiji, Okazaki, Aichi, 444-8787, Japan; Department of Physiology, Iwate Medical University, 1-1-1, Idaidori, Yahaba-cho, Shiwa-gun, Iwate, 028-3694, Japan
| | - Fumihiro Okada
- Fundamental Research Institute, Mandom Corp., 5-12, Juniken-Cho, Chuo-ku, Osaka, 540-8530, Japan
| | - Makoto Tominaga
- Thermal Biology Group, Exploratory Research Center on Life and Living Systems National Institutes of Natural Sciences, 5-1, Aza-higashiyama, Myodaiji, Okazaki, Aichi, 444-8787, Japan; Division of Cell Signaling, National Institute for Physiological Sciences, National Institutes of Natural Sciences, 5-1, Aza-higashiyama, Myodaiji, Okazaki, Aichi, 444-8787, Japan; Department of Physiological Sciences, SOKENDAI (The Graduate University for Advanced Studies), 5-1, Aza-higashiyama, Myodaiji, Okazaki, Aichi, 444-8787, Japan
| | - Ken J Ishii
- Laboratory of Mock Up Vaccine, Center for Vaccine and Adjuvant Research (CVAR), National Institutes of Biomedical Innovation, Health and Nutrition (NBIOHN), 7-6-8, Asagi, Saito, Ibaraki-City, Osaka, 567-0085, Japan; Division of Vaccine Science, Department of Microbiology and Immunology, The Institute of Medical Science, The University of Tokyo, 4-6-1, Shirokanedai, Minato-ku, Tokyo, 108-8639, Japan.
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Li S, Nguyen PT, Vu S, Yarov-Yarovoy V, Zheng J. TRPV1 Opening is Stabilized Equally by Its Four Subunits. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.26.525787. [PMID: 36747729 PMCID: PMC9900918 DOI: 10.1101/2023.01.26.525787] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Capsaicin receptor TRPV1 is a nociceptor for vanilloid molecules such as capsaicin and resiniferatoxin (RTX). Even though cryo-EM structures of TRPV1 in complex with these molecules are available, how their binding energetically favors the open conformation is not known. Here we report an approach to control the number of bound RTX molecules (0-to-4) in functional mouse TRPV1. The approach allowed direct measurements of each of the intermediate open states under equilibrium conditions at both macroscopic and single-molecule levels. We found that RTX binding to each of the four subunits contributes virtually the same activation energy, which we estimated to be 1.86 kcal/mol and found to arise predominately from destabilizing the closed conformation. We further showed that sequential bindings of RTX increase open probability without altering single-channel conductance, confirming that there is likely a single open-pore conformation for TRPV1 activated by RTX.
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Liu S, Fu L, Zhang C, Deng J, Xue W, Deng Y. Effects of Exogenous Chlorinated Amino Acetic Acid on Cadmium and Mineral Elements in Rice Seedlings. TOXICS 2023; 11:71. [PMID: 36668797 PMCID: PMC9860664 DOI: 10.3390/toxics11010071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 01/10/2023] [Accepted: 01/10/2023] [Indexed: 06/17/2023]
Abstract
To explore the effect of exogenous application of chlorinated amino acetic acid on cadmium (Cd) transport characteristics in rice seedlings, X24 and Z35 rice were taken as the research objects to carry out hydroponics experiments, and the changes of Cd content in rice seedlings, rice mineral elements and amino acid content in rice were analyzed. The results showed that exogenous application of 1.2 mmol·L-1 chlorinated amino acetic acid inhibited cadmium in shoots and roots of rice seedlings; Cd content in shoots and roots were reduced by up to 62.19% and 45.61%, respectively. The majority of cadmium was in the cell wall of shoots and roots; this decreased with the increase of the concentration of chlorinated acetic acid. In addition, the Mn content in shoots and Ca content in roots of rice seedlings increased significantly after the application of chlorinated amino acetic acid. The results of amino acid analysis showed that the contents of aspartic acid, glutamic acid and cystine in rice seedlings were increased. These results indicate that exogenous application of chlorinated amino acetic acid is beneficial to the synthesis of aspartic acid, glutamic acid and cysteine in rice seedlings, increases the content of Mn in shoots and Ca in roots of rice seedlings, and significantly alleviates cadmium stress in seedlings. This provides a theoretical basis for the development of an environmentally friendly Cd-lowering foliar fertilizer for rice.
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Affiliation(s)
- Shuangyue Liu
- Key Laboratory of Original Agro-Environmental Pollution Prevention and Control, Agro-Environmental Protection Institute, Ministry of Agriculture and Rural Affairs, Tianjin 300191, China
| | - Lin Fu
- Key Laboratory of Original Agro-Environmental Pollution Prevention and Control, Agro-Environmental Protection Institute, Ministry of Agriculture and Rural Affairs, Tianjin 300191, China
| | - Changbo Zhang
- Key Laboratory of Original Agro-Environmental Pollution Prevention and Control, Agro-Environmental Protection Institute, Ministry of Agriculture and Rural Affairs, Tianjin 300191, China
| | - Jiawei Deng
- Key Laboratory of Original Agro-Environmental Pollution Prevention and Control, Agro-Environmental Protection Institute, Ministry of Agriculture and Rural Affairs, Tianjin 300191, China
| | - Weijie Xue
- Key Laboratory of Original Agro-Environmental Pollution Prevention and Control, Agro-Environmental Protection Institute, Ministry of Agriculture and Rural Affairs, Tianjin 300191, China
| | - Yun Deng
- School of Environment and Civil Engineering, Jiangnan University, Wuxi 214122, China
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Andrei C, Zanfirescu A, Nițulescu GM, Olaru OT, Negreș S. Natural Active Ingredients and TRPV1 Modulation: Focus on Key Chemical Moieties Involved in Ligand-Target Interaction. PLANTS (BASEL, SWITZERLAND) 2023; 12:339. [PMID: 36679051 PMCID: PMC9860573 DOI: 10.3390/plants12020339] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Revised: 01/06/2023] [Accepted: 01/08/2023] [Indexed: 06/17/2023]
Abstract
Diseases such as cancer, neurological pathologies and chronic pain represent currently unmet needs. The existing pharmacotherapeutic options available for treating these conditions are limited by lack of efficiency and/or side effects. Transient receptor potential vanilloid 1 ion channel emerged as an attractive therapeutic target for developing new analgesic, anti-cancer and antiepileptic agents. Furthermore, various natural ingredients were shown to have affinity for this receptor. The aim of this narrative review was to summarize the diverse natural scaffolds of TRPV1 modulators based on their agonistic/antagonistic properties and to analyze the structure-activity relationships between the ligands and molecular targets based on the results of the existing molecular docking, mutagenesis and in vitro studies. We present here an exhaustive collection of TRPV1 modulators grouped by relevant chemical features: vanilloids, guaiacols, phenols, alkylbenzenes, monoterpenes, sesquiterpenoids, alkaloids, etc. The information herein is useful for understanding the key structural elements mediating the interaction with TRPV1 and how their structural variation impacts the interaction between the ligand and receptor. We hope this data will contribute to the design of novel effective and safe TRPV1 modulators, to help overcome the lack of effective therapeutic agents against pathologies with high morbidity and mortality.
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Gao N, Li M, Wang W, Liu Z, Guo Y. A bibliometrics analysis and visualization study of TRPV1 channel. Front Pharmacol 2023; 14:1076921. [PMID: 37025492 PMCID: PMC10070874 DOI: 10.3389/fphar.2023.1076921] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2022] [Accepted: 02/28/2023] [Indexed: 04/08/2023] Open
Abstract
Background: At the end of the 1990s, transient receptor potential vanilloid 1 (TRPV1) was first identified and cloned, serving as a key pain and heat sensor in humans. A large body of evidence have revealed its polymodal structure, complex function and wide-spread distribution, the specific mechanism of the ion channel remains unclear. Our goal here is to perform a bibliometric analysis and visualization study to present hotspots and trends in TRPV1 channel. Materials and Methods: TRPV1-related publications from inception to 2022 were retrieved from the Web of Science database. Excel, VOSviewer, and CiteSpace software were utilized for co-authorship, co-citation and co-occurrence analysis. Results: There were 9,113 publications included in the study, the number of publications increased rapidly after 1989, from 7 in 1990 to 373 in 2007, during which the number of citations per publication (CPP) also reached a peak in 2000 (CPP = 106.52). A total of 1,486 journals published TRPV1 articles, mainly belong to Q1 or Q2 divisions; The United States published the most articles (TP = 3,080), followed by Japan (TP = 1,221), China (TP = 1,217), and England (TP = 734); In recent years, the TRPV1-related research direction has been broaden to multiple fields related to inflammation, oxidative stress, and apoptosis; Keyword clustering refined the topic distributions and could be generalized as neuralgia, endogenous cannabinoid system, TRPV1 mediated airway hyperresponsiveness, involvement of apoptosis, TRPV1 antagonists as therapy targets. Conclusion: By conducting an exhaustive bibliographic search, this review refined the topic distributions and generalized as neuralgia, endogenous cannabinoid system, TRPV1 mediated airway hyperresponsiveness, involvement of apoptosis, TRPV1 antagonists as therapy targets. It is currently being clarified how exactly TRPV1 works as an ion channel, and much more in-depth basic research is needed in the future.
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Affiliation(s)
- Ning Gao
- Department of Acupuncture and Moxibustion, Guang’anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Meng Li
- Department of Gastroenterology, Guang’anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Weiming Wang
- Department of Acupuncture and Moxibustion, Guang’anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Zhen Liu
- Department of Gastroenterology, Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, China
- *Correspondence: Zhen Liu, ; Yufeng Guo,
| | - Yufeng Guo
- Department of Acupuncture and Moxibustion, Guang’anmen Hospital, China Academy of Chinese Medical Sciences, Beijing, China
- *Correspondence: Zhen Liu, ; Yufeng Guo,
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Mo X, Pang P, Wang Y, Jiang D, Zhang M, Li Y, Wang P, Geng Q, Xie C, Du HN, Zhong B, Li D, Yao J. Tyrosine phosphorylation tunes chemical and thermal sensitivity of TRPV2 ion channel. eLife 2022; 11:78301. [PMID: 35686730 PMCID: PMC9282855 DOI: 10.7554/elife.78301] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Accepted: 06/09/2022] [Indexed: 11/21/2022] Open
Abstract
Transient receptor potential vanilloid 2 (TRPV2) is a multimodal ion channel implicated in diverse physiopathological processes. Its important involvement in immune responses has been suggested such as in the macrophages’ phagocytosis process. However, the endogenous signaling cascades controlling the gating of TRPV2 remain to be understood. Here, we report that enhancing tyrosine phosphorylation remarkably alters the chemical and thermal sensitivities of TRPV2 endogenously expressed in rat bone marrow-derived macrophages and dorsal root ganglia (DRG) neurons. We identify that the protein tyrosine kinase JAK1 mediates TRPV2 phosphorylation at the molecular sites Tyr(335), Tyr(471), and Tyr(525). JAK1 phosphorylation is required for maintaining TRPV2 activity and the phagocytic ability of macrophages. We further show that TRPV2 phosphorylation is dynamically balanced by protein tyrosine phosphatase non-receptor type 1 (PTPN1). PTPN1 inhibition increases TRPV2 phosphorylation, further reducing the activation temperature threshold. Our data thus unveil an intrinsic mechanism where the phosphorylation/dephosphorylation dynamic balance sets the basal chemical and thermal sensitivity of TRPV2. Targeting this pathway will aid therapeutic interventions in physiopathological contexts. All the cells in our body have a membrane that separates their interior from the outside environment. However, studded across this barrier are numerous ion channels which allow the cell to sense and react to changes in its surroundings. This includes the ion channel TRPV2, which opens in response to mechanical pressure, certain chemical signals, or rising temperature levels. Many types of cell express TRPV2, including cells in the nervous system, muscle, and the immune system. However, despite being extensively studied, it is still not clear how TRPV2 opens and closes upon encountering high temperatures. In particular, previous work suggested that TRPV2 only responds when a cell’s surroundings reach around 52°C, which is a much higher temperature than cells inside our body normally encounter, even during a fever. To help resolve this mystery, Mo, Pang et al. studied TRPV2 in neurons responsible for sending sensory information and in immune cells called macrophages which had been extracted from rodents and grown in the laboratory. They found that when the cells were bathed in solutions containing magnesium ions, their TRPV2 channels were more sensitive to a number of different cues, including temperature. Further biochemical experiments showed that magnesium ions do not directly affect TRPV2, but increase the activity of another protein called JAK1. The magnesium ions caused JAK1 to attach specialized structures called phosphorylation tags to TRPV2. This modification (known as phosphorylation) made the channel more sensitive, allowing it to open in response to temperatures as low as 40°C. Mo, Pang et al. found that inhibiting JAK1 reduced the activity of TRPV2. Conversely, inhibiting the enzyme that removes the phosphorylation tags, called PTPN1, increased the channel’s activity. They also discovered that when JAK1 was blocked, macrophages were less able to ‘eat up’ bacteria, which is one of their main roles in the immune system. Taken together these experiments advance our understanding of how TRPV2 becomes active. The balance between the phosphorylation by JAK1 and the dephosphorylation by PTPN1 controls the temperature at which TRPV2 opens. Since TRPV2 contributes to several biological functions, including the development of the nervous system, the maintenance of heart muscles, and inflammation, these findings will be important to scientists in a broad range of fields.
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Affiliation(s)
- Xiaoyi Mo
- Department of Anesthesiology, Wuhan University, Wuhan, China
| | - Peiyuan Pang
- Department of Anesthesiology, Wuhan University, Wuhan, China
| | - Yulin Wang
- Department of Anesthesiology, Wuhan University, Wuhan, China
| | - Dexiang Jiang
- Department of Anesthesiology, Wuhan University, Wuhan, China
| | - Mengyu Zhang
- Department of Anesthesiology, Wuhan University, Wuhan, China
| | - Yang Li
- Department of Anesthesiology, Wuhan University, Wuhan, China
| | - Peiyu Wang
- Department of Anesthesiology, Wuhan University, Wuhan, China
| | - Qizhi Geng
- Department of Anesthesiology, Wuhan University, Wuhan, China
| | - Chang Xie
- Department of Anesthesiology, Wuhan University, Wuhan, China
| | - Hai-Ning Du
- Department of Anesthesiology, Wuhan University, Wuhan, China
| | - Bo Zhong
- Department of Anesthesiology, Wuhan University, Wuhan, China
| | - Dongdong Li
- Neuroscience Paris Seine, CNRS, INSERM, Sorbonne Université, Paris, France
| | - Jing Yao
- Department of Anesthesiology, Wuhan University, Wuhan, China
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12
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Luu DD, Owens AM, Mebrat MD, Van Horn WD. A molecular perspective on identifying TRPV1 thermosensitive regions and disentangling polymodal activation. Temperature (Austin) 2021; 10:67-101. [PMID: 37187836 PMCID: PMC10177694 DOI: 10.1080/23328940.2021.1983354] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2020] [Revised: 09/10/2021] [Accepted: 09/16/2021] [Indexed: 10/20/2022] Open
Abstract
TRPV1 is a polymodal receptor ion channel that is best known to function as a molecular thermometer. It is activated in diverse ways, including by heat, protons (low pH), and vanilloid compounds, such as capsaicin. In this review, we summarize molecular studies of TRPV1 thermosensing, focusing on the cross-talk between heat and other activation modes. Additional insights from TRPV1 isoforms and non-rodent/non-human TRPV1 ortholog studies are also discussed in this context. While the molecular mechanism of heat activation is still emerging, it is clear that TRPV1 thermosensing is modulated allosterically, i.e., at a distance, with contributions from many distinct regions of the channel. Similarly, current studies identify cross-talk between heat and other TRPV1 activation modes, such as protons and capsaicin, and that these modes can generally be selectively disentangled. In aggregate, this suggests that future TRPV1 molecular studies should define allosteric pathways and provide mechanistic insight, thereby enabling mode-selective manipulation of the polymodal receptor. These advances are anticipated to have significant implications in both basic and applied biomedical sciences.
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Affiliation(s)
- Dustin D. Luu
- School of Molecular Sciences, Arizona State University, Tempe, Arizona, USA
- The Biodesign Institute Virginia G. Piper Center for Personalized Diagnostics,Arizona State University, Tempe, Arizona,USA
| | - Aerial M. Owens
- School of Molecular Sciences, Arizona State University, Tempe, Arizona, USA
- The Biodesign Institute Virginia G. Piper Center for Personalized Diagnostics,Arizona State University, Tempe, Arizona,USA
| | - Mubark D. Mebrat
- School of Molecular Sciences, Arizona State University, Tempe, Arizona, USA
- The Biodesign Institute Virginia G. Piper Center for Personalized Diagnostics,Arizona State University, Tempe, Arizona,USA
| | - Wade D. Van Horn
- School of Molecular Sciences, Arizona State University, Tempe, Arizona, USA
- The Biodesign Institute Virginia G. Piper Center for Personalized Diagnostics,Arizona State University, Tempe, Arizona,USA
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13
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Nie Y, Li Y, Liu L, Ren S, Tian Y, Yang F. Molecular mechanism underlying modulation of TRPV1 heat activation by polyols. J Biol Chem 2021; 297:100806. [PMID: 34022223 PMCID: PMC8214097 DOI: 10.1016/j.jbc.2021.100806] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 05/14/2021] [Accepted: 05/18/2021] [Indexed: 11/30/2022] Open
Abstract
Sensing noxiously high temperatures is crucial for living organisms to avoid heat-induced injury. The TRPV1 channel has long been known as a sensor for noxious heat. However, the mechanism of how this channel is activated by heat remains elusive. Here we found that a series of polyols including sucrose, sorbitol, and hyaluronan significantly elevate the heat activation threshold temperature of TRPV1. The modulatory effects of these polyols were only observed when they were perfused extracellularly. Interestingly, mutation of residues E601 and E649 in the outer pore region of TRPV1 largely abolished the effects of these polyols. We further observed that intraplantar injection of polyols into the hind paws of rats reduced their heat-induced pain response. Our observations not only suggest that the extracellular regions of TRPV1 are critical for the modulation of heat activation by polyols, but also indicate a potential role of polyols in reducing heat-induced pain sensation.
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Affiliation(s)
- Yingying Nie
- Department of Pharmacology, School of Pharmacy, Qingdao University Medical College, Qingdao, China
| | - Yanxin Li
- Department of Pharmacology, School of Pharmacy, Qingdao University Medical College, Qingdao, China
| | - Lei Liu
- Department of Pharmacology, School of Pharmacy, Qingdao University Medical College, Qingdao, China
| | - Shouyan Ren
- Department of Otorhinolaryngology, The Affiliated Hospital of Qingdao University, Qingdao, Shangdong, China
| | - Yuhua Tian
- Department of Pharmacology, School of Pharmacy, Qingdao University Medical College, Qingdao, China.
| | - Fan Yang
- Department of Biophysics, and Kidney Disease Center of the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang Province, China.
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14
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Vu S, Singh V, Wulff H, Yarov-Yarovoy V, Zheng J. New capsaicin analogs as molecular rulers to define the permissive conformation of the mouse TRPV1 ligand-binding pocket. eLife 2020; 9:62039. [PMID: 33164749 PMCID: PMC7671684 DOI: 10.7554/elife.62039] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Accepted: 11/08/2020] [Indexed: 12/23/2022] Open
Abstract
The capsaicin receptor TRPV1 is an outstanding representative of ligand-gated ion channels in ligand selectivity and sensitivity. However, molecular interactions that stabilize the ligand-binding pocket in its permissive conformation, and how many permissive conformations the ligand-binding pocket may adopt, remain unclear. To answer these questions, we designed a pair of novel capsaicin analogs to increase or decrease the ligand size by about 1.5 Å without altering ligand chemistry. Together with capsaicin, these ligands form a set of molecular rulers for investigating ligand-induced conformational changes. Computational modeling and functional tests revealed that structurally these ligands alternate between drastically different binding poses but stabilize the ligand-binding pocket in nearly identical permissive conformations; functionally, they all yielded a stable open state despite varying potencies. Our study suggests the existence of an optimal ligand-binding pocket conformation for capsaicin-mediated TRPV1 activation gating, and reveals multiple ligand-channel interactions that stabilize this permissive conformation.
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Affiliation(s)
- Simon Vu
- Department of Physiology and Membrane Biology, University of California Davis, School of Medicine, Davis, United States
| | - Vikrant Singh
- Department of Pharmacology, University of California Davis, School of Medicine, Davis, United States
| | - Heike Wulff
- Department of Pharmacology, University of California Davis, School of Medicine, Davis, United States
| | - Vladimir Yarov-Yarovoy
- Department of Physiology and Membrane Biology, University of California Davis, School of Medicine, Davis, United States
| | - Jie Zheng
- Department of Physiology and Membrane Biology, University of California Davis, School of Medicine, Davis, United States
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15
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Yang F, Xu L, Lee BH, Xiao X, Yarov‐Yarovoy V, Zheng J. An Unorthodox Mechanism Underlying Voltage Sensitivity of TRPV1 Ion Channel. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2020; 7:2000575. [PMID: 33101845 PMCID: PMC7578911 DOI: 10.1002/advs.202000575] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Revised: 08/05/2020] [Indexed: 05/10/2023]
Abstract
While the capsaicin receptor transient receptor potential vanilloid 1 (TRPV1) channel is a polymodal nociceptor for heat, capsaicin, and protons, the channel's responses to each of these stimuli are profoundly regulated by membrane potential, damping or even prohibiting its response at negative voltages and amplifying its response at positive voltages. Therefore, voltage sensitivity of TRPV1 is anticipated to play an important role in shaping pain responses. How voltage regulates TRPV1 activation remains unknown. Here, it is shown that voltage sensitivity does not originate from the S4 segment like classic voltage-gated ion channels; instead, outer pore acidic residues directly partake in voltage-sensitive activation, with their negative charges collectively constituting the observed gating charges. Outer pore gating-charge movement is titratable by extracellular pH and is allosterically coupled to channel activation, likely by influencing the upper gate in the ion selectivity filter. Elucidating this unorthodox voltage-gating process provides a mechanistic foundation for understanding TRPV1 polymodal gating and opens the door to novel approaches regulating channel activity for pain management.
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Affiliation(s)
- Fan Yang
- Department of Biophysics, and Kidney Disease Center of the First Affiliated HospitalZhejiang University School of Medicine866 Yuhangtang RoadHangzhouZhejiang310058China
- Department of Physiology and Membrane BiologyUniversity of California, DavisOne Shields AvenueDavisCA95616USA
| | - Lizhen Xu
- Department of Biophysics, and Kidney Disease Center of the First Affiliated HospitalZhejiang University School of Medicine866 Yuhangtang RoadHangzhouZhejiang310058China
| | - Bo Hyun Lee
- Department of Physiology and Membrane BiologyUniversity of California, DavisOne Shields AvenueDavisCA95616USA
| | - Xian Xiao
- Department of Physiology and Membrane BiologyUniversity of California, DavisOne Shields AvenueDavisCA95616USA
- School of Life Sciences, Westlake Institute for Advanced StudyWestlake UniversityShilongshan Road No. 18, Xihu DistrictHangzhouZhejiang310064China
| | - Vladimir Yarov‐Yarovoy
- Department of Physiology and Membrane BiologyUniversity of California, DavisOne Shields AvenueDavisCA95616USA
| | - Jie Zheng
- Department of Physiology and Membrane BiologyUniversity of California, DavisOne Shields AvenueDavisCA95616USA
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16
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Du G, Tian Y, Yao Z, Vu S, Zheng J, Chai L, Wang K, Yang S. A specialized pore turret in the mammalian cation channel TRPV1 is responsible for distinct and species-specific heat activation thresholds. J Biol Chem 2020; 295:9641-9649. [PMID: 32461255 DOI: 10.1074/jbc.ra120.013037] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 05/20/2020] [Indexed: 11/06/2022] Open
Abstract
The transient receptor potential vanilloid 1 (TRPV1) channel is a heat-activated cation channel that plays a crucial role in ambient temperature detection and thermal homeostasis. Although several structural features of TRPV1 have been shown to be involved in heat-induced activation of the gating process, the physiological significance of only a few of these key elements has been evaluated in an evolutionary context. Here, using transient expression in HEK293 cells, electrophysiological recordings, and molecular modeling, we show that the pore turret contains both structural and functional determinants that set the heat activation thresholds of distinct TRPV1 orthologs in mammals whose body temperatures fluctuate widely. We found that TRPV1 from the bat Carollia brevicauda exhibits a lower threshold temperature of channel activation than does its human ortholog and three bat-specific amino acid substitutions located in the pore turret are sufficient to determine this threshold temperature. Furthermore, the structure of the TRPV1 pore turret appears to be of physiological and evolutionary significance for differentiating the heat-activated threshold among species-specific TRPV1 orthologs. These findings support a role for the TRPV1 pore turret in tuning the heat-activated threshold, and they suggest that its evolution was driven by adaption to specific physiological traits among mammals exposed to variable temperatures.
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Affiliation(s)
- Guangxu Du
- Department of Pharmacology, Qingdao University School of Pharmacy, Qingdao, Shandong, China
| | - Yuhua Tian
- Department of Pharmacology, Qingdao University School of Pharmacy, Qingdao, Shandong, China
| | - Zhihao Yao
- Department of Pharmacology, Qingdao University School of Pharmacy, Qingdao, Shandong, China.,Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences/Key Laboratory of Bioactive Peptides of the Yunnan Province Kunming Institute of Zoology, Kunming, Yunnan China
| | - Simon Vu
- University of California Davis, School of Medicine, Davis, California, USA
| | - Jie Zheng
- University of California Davis, School of Medicine, Davis, California, USA
| | - Longhui Chai
- College of Wildlife and Protected Area, Northeast Forestry University, Harbin, China
| | - KeWei Wang
- Department of Pharmacology, Qingdao University School of Pharmacy, Qingdao, Shandong, China
| | - Shilong Yang
- College of Wildlife and Protected Area, Northeast Forestry University, Harbin, China
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17
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Zhu A, Aierken A, Yao Z, Vu S, Tian Y, Zheng J, Yang S, Yang F. A centipede toxin causes rapid desensitization of nociceptor TRPV1 ion channel. Toxicon 2020; 178:41-49. [PMID: 32097697 DOI: 10.1016/j.toxicon.2020.02.016] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 02/05/2020] [Accepted: 02/17/2020] [Indexed: 10/24/2022]
Abstract
The nociceptive transient receptor potential vanilloid 1 (TRPV1) ion channel is a polymodal receptor for multiple painful stimuli, hence actively pursued as a target for analgesic drugs. We identified a small peptide toxin RhTx2 from the Chinese red-headed centipede that strongly modulates TRPV1 activities. RhTx2, a 31-amino-acid peptide, is similar to a TRPV1-activating toxin RhTx we have previously discovered but with four extra amino acids at the N terminus. We observed that, like RhTx, RhTx2 activated TRPV1, but RhTx2 rapidly desensitized the channel upon prolonged exposure. Desensitization was achieved by reducing both the open probability and the single-channel conductance. RhTx2 is not only a tool to study the desensitization mechanism of TRPV1, but also a promising starting molecule for developing novel analgesics.
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Affiliation(s)
- Aiqin Zhu
- Department of Pharmacology, Qingdao University School of Pharmacy, Qingdao, Shandong, China; Department of Biophysics and Kidney Disease Center, The First Affiliated Hospital, Institute of Neuroscience, National Health Commission and Chinese Academy of Medical Sciences Key Laboratory of Medical Neurobiology, Zhejiang University School of Medicine, Hangzhou 310058, Zhejiang Province, China
| | - Aerziguli Aierken
- Department of Biophysics and Kidney Disease Center, The First Affiliated Hospital, Institute of Neuroscience, National Health Commission and Chinese Academy of Medical Sciences Key Laboratory of Medical Neurobiology, Zhejiang University School of Medicine, Hangzhou 310058, Zhejiang Province, China
| | - Zhihao Yao
- Department of Pharmacology, Qingdao University School of Pharmacy, Qingdao, Shandong, China; Key Laboratory of Animal Models and Human Disease Mechanisms of Chinese Academy of Sciences/Key Laboratory of bioactive peptides of Yunnan Province, Kunming Institute of Zoology, Kunming, 650223, Yunnan, China
| | - Simon Vu
- Department of Physiology and Membrane Biology, UC Davis School of Medicine, Davis, CA, 95616, USA
| | - Yuhua Tian
- Department of Pharmacology, Qingdao University School of Pharmacy, Qingdao, Shandong, China.
| | - Jie Zheng
- Department of Physiology and Membrane Biology, UC Davis School of Medicine, Davis, CA, 95616, USA.
| | - Shilong Yang
- Key Laboratory of Animal Models and Human Disease Mechanisms of Chinese Academy of Sciences/Key Laboratory of bioactive peptides of Yunnan Province, Kunming Institute of Zoology, Kunming, 650223, Yunnan, China.
| | - Fan Yang
- Department of Biophysics and Kidney Disease Center, The First Affiliated Hospital, Institute of Neuroscience, National Health Commission and Chinese Academy of Medical Sciences Key Laboratory of Medical Neurobiology, Zhejiang University School of Medicine, Hangzhou 310058, Zhejiang Province, China.
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18
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Jara-Oseguera A, Huffer KE, Swartz KJ. The ion selectivity filter is not an activation gate in TRPV1-3 channels. eLife 2019; 8:51212. [PMID: 31724952 PMCID: PMC6887487 DOI: 10.7554/elife.51212] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Accepted: 11/13/2019] [Indexed: 12/13/2022] Open
Abstract
Activation of TRPV1 channels in sensory neurons results in opening of a cation permeation pathway that triggers the sensation of pain. Opening of TRPV1 has been proposed to involve two gates that appear to prevent ion permeation in the absence of activators: the ion selectivity filter on the external side of the pore and the S6 helices that line the cytosolic half of the pore. Here we measured the access of thiol-reactive ions across the selectivity filters in rodent TRPV1-3 channels. Although our results are consistent with structural evidence that the selectivity filters in these channels are dynamic, they demonstrate that cations can permeate the ion selectivity filters even when channels are closed. Our results suggest that the selectivity filters in TRPV1-3 channels do not function as activation gates but might contribute to coupling structural rearrangements in the external pore to those in the cytosolic S6 gate.
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Affiliation(s)
- Andrés Jara-Oseguera
- Molecular Physiology and Biophysics Section, Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, United States
| | - Katherine E Huffer
- Molecular Physiology and Biophysics Section, Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, United States
| | - Kenton J Swartz
- Molecular Physiology and Biophysics Section, Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, United States
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19
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Bujak JK, Kosmala D, Szopa IM, Majchrzak K, Bednarczyk P. Inflammation, Cancer and Immunity-Implication of TRPV1 Channel. Front Oncol 2019; 9:1087. [PMID: 31681615 PMCID: PMC6805766 DOI: 10.3389/fonc.2019.01087] [Citation(s) in RCA: 150] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Accepted: 10/02/2019] [Indexed: 12/22/2022] Open
Abstract
Process of inflammation and complex interactions between immune and cancer cells within tumor microenvironment are known to drive and shape the outcome of the neoplastic disease. Recent studies increasingly show that ion channels can be used as potential targets to modulate immune response and to treat inflammatory disorders and cancer. The action of both innate and adaptive immune cells is tightly regulated by ionic signals provided by a network of distinct ion channels. TRPV1 channel, known as a capsaicin receptor, was recently documented to be expressed on the cells of the immune system but also aberrantly expressed in the several tumor types. It is activated by heat, protons, proinflammatory cytokines, and associated with pain and inflammation. TRPV1 channel is not only involved in calcium signaling fundamental for many cellular processes but also takes part in cell-environment crosstalk influencing cell behavior. Furthermore, in several studies, activation of TRPV1 by capsaicin was associated with anti-cancer effects. Therefore, TRPV1 provides a potential link between the process of inflammation, cancer and immunity, and offers new treatment possibilities. Nevertheless, in many cases, results regarding TRPV1 are contradictory and need further refinement. In this review we present the summary of the data related to the role of TRPV1 channel in the process of inflammation, cancer and immunity, limitations of the studies, and directions for future research.
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Affiliation(s)
- Joanna Katarzyna Bujak
- Department of Physiological Sciences, Faculty of Veterinary Medicine, Warsaw University of Life Sciences, Warsaw, Poland
| | - Daria Kosmala
- Department of Physiological Sciences, Faculty of Veterinary Medicine, Warsaw University of Life Sciences, Warsaw, Poland
| | - Iwona Monika Szopa
- Department of Physiological Sciences, Faculty of Veterinary Medicine, Warsaw University of Life Sciences, Warsaw, Poland
| | - Kinga Majchrzak
- Department of Physiological Sciences, Faculty of Veterinary Medicine, Warsaw University of Life Sciences, Warsaw, Poland
| | - Piotr Bednarczyk
- Department of Biophysics, Warsaw University of Life Sciences, Warsaw, Poland
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20
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Huang R, Wang F, Yang Y, Ma W, Lin Z, Cheng N, Long Y, Deng S, Li Z. Recurrent activations of transient receptor potential vanilloid-1 and vanilloid-4 promote cellular proliferation and migration in esophageal squamous cell carcinoma cells. FEBS Open Bio 2019; 9:206-225. [PMID: 30761248 PMCID: PMC6356177 DOI: 10.1002/2211-5463.12570] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Revised: 06/19/2018] [Accepted: 10/23/2018] [Indexed: 12/27/2022] Open
Abstract
Some members of the transient receptor potential vanilloid (TRPV) subfamily of cation channels are thermosensitive. Earlier studies have revealed the distribution and functions of these thermo‐TRPVs (TRPV1–4) in various organs, but their expression and function in the human esophagus are not fully understood. Here, we probed for the expression of the thermo‐TRPVs in one nontumor human esophageal squamous cell line and two esophageal squamous cell carcinoma (ESCC) cell lines. TRPV1, TRPV2, and TRPV4 proteins were found to be upregulated in ESCC cells, while TRPV3 was not detectable in any of these cell lines. Subsequently, channel function was evaluated via monitoring of Ca2+ transients by Ca2+ imaging and nonselective cation channel currents were recorded by whole‐cell patch clamp. We found that TRPV4 was activated by heat at 28 °C–35 °C, whereas TRPV1 and TRPV2 were activated by higher, noxious temperatures (44 °C and 53 °C, respectively). Furthermore, TRPV1 was activated by capsaicin (EC50 = 20.32 μm), and this effect was antagonized by AMG9810; TRPV2 was activated by a newly developed cannabinoid compound, O1821, and inhibited by tranilast. In addition, TRPV4 was activated by hypotonic solutions (220 m Osm), and this effect was abolished by ruthenium red. The effects of TRPV1 and TRPV4 on ESCC were also explored. Our data, for the first time, showed that the overactivation of TRPV1 and TRPV4 promoted the proliferation and/or migration of ESCC cells. In summary, TRPV1, TRPV2, and TRPV4 were functionally expressed in human esophageal squamous cells, and thermo‐TRPVs might play an important role in the development of ESCC.
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Affiliation(s)
- Rongqi Huang
- Key Laboratory of Regenerative Biology Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine Guangzhou Institutes of Biomedicine and Health Chinese Academy of Sciences Guangzhou China.,University of Chinese Academy of Sciences Beijing China
| | - Fei Wang
- Key Laboratory of Regenerative Biology Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine Guangzhou Institutes of Biomedicine and Health Chinese Academy of Sciences Guangzhou China
| | - Yuchen Yang
- Key Laboratory of Regenerative Biology Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine Guangzhou Institutes of Biomedicine and Health Chinese Academy of Sciences Guangzhou China
| | - Wenbo Ma
- Key Laboratory of Regenerative Biology Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine Guangzhou Institutes of Biomedicine and Health Chinese Academy of Sciences Guangzhou China
| | - Zuoxian Lin
- Key Laboratory of Regenerative Biology Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine Guangzhou Institutes of Biomedicine and Health Chinese Academy of Sciences Guangzhou China
| | - Na Cheng
- Key Laboratory of Regenerative Biology Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine Guangzhou Institutes of Biomedicine and Health Chinese Academy of Sciences Guangzhou China.,Department of Anatomy and Neurobiology Xiangya School of Medicine Central South University Changsha China
| | - Yan Long
- Key Laboratory of Regenerative Biology Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine Guangzhou Institutes of Biomedicine and Health Chinese Academy of Sciences Guangzhou China
| | - Sihao Deng
- Department of Anatomy and Neurobiology Xiangya School of Medicine Central South University Changsha China
| | - Zhiyuan Li
- Key Laboratory of Regenerative Biology Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine Guangzhou Institutes of Biomedicine and Health Chinese Academy of Sciences Guangzhou China.,University of Chinese Academy of Sciences Beijing China.,Department of Anatomy and Neurobiology Xiangya School of Medicine Central South University Changsha China.,GZMU-GIBH Joint School of Life Sciences Guangzhou Medical University China
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21
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Sánchez-Moreno A, Guevara-Hernández E, Contreras-Cervera R, Rangel-Yescas G, Ladrón-de-Guevara E, Rosenbaum T, Islas LD. Irreversible temperature gating in trpv1 sheds light on channel activation. eLife 2018; 7:36372. [PMID: 29869983 PMCID: PMC5999395 DOI: 10.7554/elife.36372] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2018] [Accepted: 05/26/2018] [Indexed: 02/06/2023] Open
Abstract
Temperature-activated TRP channels or thermoTRPs are among the only proteins that can directly convert temperature changes into changes in channel open probability. In spite of a wealth of functional and structural information, the mechanism of temperature activation remains unknown. We have carefully characterized the repeated activation of TRPV1 by thermal stimuli and discovered a previously unknown inactivation process, which is irreversible. We propose that this form of gating in TRPV1 channels is a consequence of the heat absorption process that leads to channel opening.
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Affiliation(s)
| | - Eduardo Guevara-Hernández
- Departamento de Fisiología, Facultad de Medicina, México City, México.,Instituto de Fisiología Celular, México City, México
| | | | | | | | | | - León D Islas
- Departamento de Fisiología, Facultad de Medicina, México City, México
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22
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Ruigrok HJ, Arnaud-Cormos D, Hurtier A, Poque E, de Gannes FP, Ruffié G, Bonnaudin F, Lagroye I, Sojic N, Arbault S, Lévêque P, Veyret B, Percherancier Y. Activation of the TRPV1 Thermoreceptor Induced by Modulated or Unmodulated 1800 MHz Radiofrequency Field Exposure. Radiat Res 2017; 189:95-103. [PMID: 29059001 DOI: 10.1667/rr14877.1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The existence of effects of radiofrequency field exposure at environmental levels on living tissues and organisms remains controversial, in particular regarding potential "nonthermal" effects produced in the absence of temperature elevation. Therefore, we investigated whether TRPV1, one of the most studied thermosensitive channels, can be activated by the heat produced by radiofrequency fields and by some specific nonthermal interaction with the fields. We have recently shown that TRPV1 activation can be assessed in real-time on live cells using the bioluminescence resonance energy transfer technique. Taking advantage of this innovative assay, we monitored TRPV1 thermal and chemical modes of activation under radiofrequency exposure at 1800 MHz using different signals (CW, GSM, UMTS, LTE, Wi-Fi and WiMAX) at specific absorption rates between 8 and 32 W/kg. We showed that, as expected, TRPV1 channels were activated by the heat produced by radiofrequency field exposure of transiently-transfected HEK293T cells, but found no evidence of TRPV1 activation in the absence of temperature elevation under radiofrequency field exposure. There was no evidence either that, at fixed temperature, radiofrequency exposure altered the maximal efficacy of the agonist Capsaicin to activate TRPV1.
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Affiliation(s)
- Hermanus J Ruigrok
- a Laboratoire de l'Intégration du Matériau au Système, Centre National de la Recherche Scientifique (CNRS) UMR 5218, Talence, France.,b Université de Bordeaux, Talence, France
| | | | - Annabelle Hurtier
- a Laboratoire de l'Intégration du Matériau au Système, Centre National de la Recherche Scientifique (CNRS) UMR 5218, Talence, France.,b Université de Bordeaux, Talence, France
| | - Emmanuelle Poque
- a Laboratoire de l'Intégration du Matériau au Système, Centre National de la Recherche Scientifique (CNRS) UMR 5218, Talence, France.,b Université de Bordeaux, Talence, France
| | - Florence Poulletier de Gannes
- a Laboratoire de l'Intégration du Matériau au Système, Centre National de la Recherche Scientifique (CNRS) UMR 5218, Talence, France.,b Université de Bordeaux, Talence, France
| | - Gilles Ruffié
- a Laboratoire de l'Intégration du Matériau au Système, Centre National de la Recherche Scientifique (CNRS) UMR 5218, Talence, France.,b Université de Bordeaux, Talence, France
| | - Fabrice Bonnaudin
- a Laboratoire de l'Intégration du Matériau au Système, Centre National de la Recherche Scientifique (CNRS) UMR 5218, Talence, France.,b Université de Bordeaux, Talence, France
| | - Isabelle Lagroye
- a Laboratoire de l'Intégration du Matériau au Système, Centre National de la Recherche Scientifique (CNRS) UMR 5218, Talence, France.,b Université de Bordeaux, Talence, France.,e Paris Sciences et Lettres - EPHE Research University, Paris, France
| | - Neso Sojic
- b Université de Bordeaux, Talence, France.,d ISM, CNRS UMR 5255, NSYSA Group, ENSCBP, Pessac, France
| | - Stéphane Arbault
- b Université de Bordeaux, Talence, France.,d ISM, CNRS UMR 5255, NSYSA Group, ENSCBP, Pessac, France
| | - Philippe Lévêque
- c Université de Limoges, CNRS, XLIM, UMR 7252, F-87000 Limoges, France
| | - Bernard Veyret
- a Laboratoire de l'Intégration du Matériau au Système, Centre National de la Recherche Scientifique (CNRS) UMR 5218, Talence, France.,b Université de Bordeaux, Talence, France
| | - Yann Percherancier
- a Laboratoire de l'Intégration du Matériau au Système, Centre National de la Recherche Scientifique (CNRS) UMR 5218, Talence, France.,b Université de Bordeaux, Talence, France
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23
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Gómez M, González A, Moenne F, Sáez C, Moenne A. Copper-induced early responses involve the activation of Transient Receptor Potential (TRP) channels, release of amino acids, serotonin and adrenalin, and activation of homologs of glutamate, adrenalin and serotonin receptors in the marine alga Ulva compressa. ALGAL RES 2017. [DOI: 10.1016/j.algal.2017.07.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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24
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Understand spiciness: mechanism of TRPV1 channel activation by capsaicin. Protein Cell 2017; 8:169-177. [PMID: 28044278 PMCID: PMC5326624 DOI: 10.1007/s13238-016-0353-7] [Citation(s) in RCA: 181] [Impact Index Per Article: 25.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Accepted: 11/22/2016] [Indexed: 11/06/2022] Open
Abstract
Capsaicin in chili peppers bestows the sensation of spiciness. Since the discovery of its receptor, transient receptor potential vanilloid 1 (TRPV1) ion channel, how capsaicin activates this channel has been under extensive investigation using a variety of experimental techniques including mutagenesis, patch-clamp recording, crystallography, cryo-electron microscopy, computational docking and molecular dynamic simulation. A framework of how capsaicin binds and activates TRPV1 has started to merge: capsaicin binds to a pocket formed by the channel’s transmembrane segments, where it takes a “tail-up, head-down” configuration. Binding is mediated by both hydrogen bonds and van der Waals interactions. Upon binding, capsaicin stabilizes the open state of TRPV1 by “pull-and-contact” with the S4-S5 linker. Understanding the ligand-host interaction will greatly facilitate pharmaceutical efforts to develop novel analgesics targeting TRPV1.
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25
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Exploring functional roles of TRPV1 intracellular domains with unstructured peptide-insertion screening. Sci Rep 2016; 6:33827. [PMID: 27666400 PMCID: PMC5035920 DOI: 10.1038/srep33827] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2016] [Accepted: 08/30/2016] [Indexed: 01/23/2023] Open
Abstract
TRPV1 is a polymodal nociceptor for diverse physical and chemical stimuli that interact with different parts of the channel protein. Recent cryo-EM studies revealed detailed channel structures, opening the door for mapping structural elements mediating activation by each stimulus. Towards this goal, here we have combined unstructured peptide-insertion screening (UPS) with electrophysiological and fluorescence recordings to explore structural and functional roles of the intracellular regions of TRPV1 in mediating various activation stimuli. We found that most of the tightly packed protein regions did not tolerate structural perturbation by UPS when tested, indicating that structural integrity of the intracellular region is critical. In agreement with previous reports, Ca2+-dependent desensitization is strongly dependent on both intracellular N- and C-terminal domains; insertions of an unstructured peptide between these domains and the transmembrane core domain nearly eliminated Ca2+-dependent desensitization. In contrast, channel activations by capsaicin, low pH, divalent cations, and even heat are mostly intact in mutant channels containing the same insertions. These observations suggest that the transmembrane core domain of TRPV1, but not the intracellular domains, is responsible for sensing these stimuli.
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26
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Jara-Oseguera A, Bae C, Swartz KJ. An external sodium ion binding site controls allosteric gating in TRPV1 channels. eLife 2016; 5. [PMID: 26882503 PMCID: PMC4764576 DOI: 10.7554/elife.13356] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2015] [Accepted: 01/28/2016] [Indexed: 12/11/2022] Open
Abstract
TRPV1 channels in sensory neurons are integrators of painful stimuli and heat, yet how they integrate diverse stimuli and sense temperature remains elusive. Here, we show that external sodium ions stabilize the TRPV1 channel in a closed state, such that removing the external ion leads to channel activation. In studying the underlying mechanism, we find that the temperature sensors in TRPV1 activate in two steps to favor opening, and that the binding of sodium to an extracellular site exerts allosteric control over temperature-sensor activation and opening of the pore. The binding of a tarantula toxin to the external pore also exerts control over temperature-sensor activation, whereas binding of vanilloids influences temperature-sensitivity by largely affecting the open/closed equilibrium. Our results reveal a fundamental role of the external pore in the allosteric control of TRPV1 channel gating and provide essential constraints for understanding how these channels can be tuned by diverse stimuli. DOI:http://dx.doi.org/10.7554/eLife.13356.001 Humans and other mammals sense elevated heat and other painful stimuli via a sensory ion channel protein called TRPV1. Ion channels create pores in the outer membrane of cells and act as gates that open and close to regulate the flow of ions into and out of cells. This flow of ions generates electrical signals that sensory neurons use to communicate information about the environment to the brain. The TRPV1 channel is opened by heat, but also by venom toxins, acid and the active ingredient in hot chilli peppers. The fluid that surrounds animal cells often contains high levels of sodium ions, and these ions flow through TRPV1 channels when they are open. Also, when sodium ions are removed from the fluid surrounding a cell, TRPV1 channels will spontaneously open. It is not known why this happens, but it suggests that sodium ions help to regulate the activity of the TRPV1 channel, and despite having been extensively studied, it remains unclear how this channel senses temperature and responds to other harmful stimuli. Jara-Oseguera et al. have now investigated the role of sodium ions in activating TRPV1 in cells grown in the laboratory. The experiments involved a technique that records the movement of ions through TRPV1 channels in the cell surface membrane while exposing the cell to various stimuli that open or close the channels. The results showed that TRPV1 contains an important site on its outer surface that binds sodium ions and fine-tunes the channel’s properties. This enables the channel to be activated by potentially damaging temperatures. Further analysis revealed that TRPV1 undergoes at least two distinct physical changes in response to heat and that the binding of sodium ions to the channel’s outer structure regulates one of these changes. Jara-Oseguera et al. went on to discover that the binding of a tarantula toxin to the outer surface of TRPV1 renders the channel insensitive to changes in temperature. These findings suggest that structural changes to the external part of this channel protein are closely associated with its ability to sense temperature, possibly because this region of the protein is directly responsible for detecting changes in temperature. These findings shed light on how this channel detects and responds to dangerously high temperatures, as well to other harmful stimuli. An aim for future studies is to pinpoint the specific regions of the protein that form the sodium-binding sites and to test the hypothesis that temperature sensors are located on the outer surface of the protein. DOI:http://dx.doi.org/10.7554/eLife.13356.002
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Affiliation(s)
- Andres Jara-Oseguera
- Molecular Physiology and Biophysics Section, Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, United States
| | - Chanhyung Bae
- Molecular Physiology and Biophysics Section, Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, United States
| | - Kenton J Swartz
- Molecular Physiology and Biophysics Section, Porter Neuroscience Research Center, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, United States
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27
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Zagotta WN, Gordon MT, Senning EN, Munari MA, Gordon SE. Measuring distances between TRPV1 and the plasma membrane using a noncanonical amino acid and transition metal ion FRET. ACTA ACUST UNITED AC 2016; 147:201-16. [PMID: 26755770 PMCID: PMC4727949 DOI: 10.1085/jgp.201511531] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Accepted: 12/17/2015] [Indexed: 12/14/2022]
Abstract
Transition metal ion FRET between a noncanonical fluorescent amino acid incorporated into TRPV1 and metal ions bound to the cell plasma can be used to measure distances and dynamics between cytosolic domains of proteins and the membrane. Despite recent advances, the structure and dynamics of membrane proteins in cell membranes remain elusive. We implemented transition metal ion fluorescence resonance energy transfer (tmFRET) to measure distances between sites on the N-terminal ankyrin repeat domains (ARDs) of the pain-transducing ion channel TRPV1 and the intracellular surface of the plasma membrane. To preserve the native context, we used unroofed cells, and to specifically label sites in TRPV1, we incorporated a fluorescent, noncanonical amino acid, L-ANAP. A metal chelating lipid was used to decorate the plasma membrane with high-density/high-affinity metal-binding sites. The fluorescence resonance energy transfer (FRET) efficiencies between L-ANAP in TRPV1 and Co2+ bound to the plasma membrane were consistent with the arrangement of the ARDs in recent cryoelectron microscopy structures of TRPV1. No change in tmFRET was observed with the TRPV1 agonist capsaicin. These results demonstrate the power of tmFRET for measuring structure and rearrangements of membrane proteins relative to the cell membrane.
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Affiliation(s)
- William N Zagotta
- Department of Physiology and Biophysics, University of Washington, Seattle, WA 98195
| | - Moshe T Gordon
- Department of Physiology and Biophysics, University of Washington, Seattle, WA 98195
| | - Eric N Senning
- Department of Physiology and Biophysics, University of Washington, Seattle, WA 98195
| | - Mika A Munari
- Department of Physiology and Biophysics, University of Washington, Seattle, WA 98195
| | - Sharona E Gordon
- Department of Physiology and Biophysics, University of Washington, Seattle, WA 98195
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28
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Yang S, Yang F, Wei N, Hong J, Li B, Luo L, Rong M, Yarov-Yarovoy V, Zheng J, Wang K, Lai R. A pain-inducing centipede toxin targets the heat activation machinery of nociceptor TRPV1. Nat Commun 2015; 6:8297. [PMID: 26420335 PMCID: PMC4589873 DOI: 10.1038/ncomms9297] [Citation(s) in RCA: 88] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Accepted: 08/07/2015] [Indexed: 02/06/2023] Open
Abstract
The capsaicin receptor TRPV1 ion channel is a polymodal nociceptor that responds to heat with exquisite sensitivity through an unknown mechanism. Here we report the identification of a novel toxin, RhTx, from the venom of the Chinese red-headed centipede that potently activates TRPV1 to produce excruciating pain. RhTx is a 27-amino-acid small peptide that forms a compact polarized molecule with very rapid binding kinetics and high affinity for TRPV1. We show that RhTx targets the channel's heat activation machinery to cause powerful heat activation at body temperature. The RhTx-TRPV1 interaction is mediated by the toxin's highly charged C terminus, which associates tightly to the charge-rich outer pore region of the channel where it can directly interact with the pore helix and turret. These findings demonstrate that RhTx binding to the outer pore can induce TRPV1 heat activation, therefore providing crucial new structural information on the heat activation machinery.
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Affiliation(s)
- Shilong Yang
- Key Laboratory of Animal Models and Human Disease Mechanisms, Chinese Academy of Sciences, Kunming Institute of Zoology, Kunming 650223, Yunnan, China
- University of Chinese Academy of Sciences, Beijing 100009, China
| | - Fan Yang
- Department of Physiology and Membrane Biology, University of California, Davis, California 95616, USA
| | - Ningning Wei
- Department of Neurobiology, Neuroscience Research Institute, Peking University Health Science Center, Beijing 100191, China
| | - Jing Hong
- College of Biological Science and Engineering, Fuzhou University, Fuzhou 350116, China
| | - Bowen Li
- Key Laboratory of Animal Models and Human Disease Mechanisms, Chinese Academy of Sciences, Kunming Institute of Zoology, Kunming 650223, Yunnan, China
- University of Chinese Academy of Sciences, Beijing 100009, China
| | - Lei Luo
- Key Laboratory of Animal Models and Human Disease Mechanisms, Chinese Academy of Sciences, Kunming Institute of Zoology, Kunming 650223, Yunnan, China
- University of Chinese Academy of Sciences, Beijing 100009, China
| | - Mingqiang Rong
- Key Laboratory of Animal Models and Human Disease Mechanisms, Chinese Academy of Sciences, Kunming Institute of Zoology, Kunming 650223, Yunnan, China
| | - Vladimir Yarov-Yarovoy
- Department of Physiology and Membrane Biology, University of California, Davis, California 95616, USA
| | - Jie Zheng
- Department of Physiology and Membrane Biology, University of California, Davis, California 95616, USA
| | - KeWei Wang
- Department of Neurobiology, Neuroscience Research Institute, Peking University Health Science Center, Beijing 100191, China
- Department of Molecular and Cellular Pharmacology, PKU-IDG/McGovern Institute for Brain Research, Peking University School of Pharmaceutical Sciences, Beijing 100191, China
- Department of Pharmacology, Qingdao University, Qingdao 266021, China
| | - Ren Lai
- Key Laboratory of Animal Models and Human Disease Mechanisms, Chinese Academy of Sciences, Kunming Institute of Zoology, Kunming 650223, Yunnan, China
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29
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Lee BH, Zheng J. Proton block of proton-activated TRPV1 current. ACTA ACUST UNITED AC 2015; 146:147-59. [PMID: 26170176 PMCID: PMC4516785 DOI: 10.1085/jgp.201511386] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2015] [Accepted: 06/08/2015] [Indexed: 12/29/2022]
Abstract
H+ not only activates the TRPV1 cation channel but inhibits ion permeation, yielding a prominent OFF current response. The TRPV1 cation channel is a polymodal nociceptor that is activated by heat and ligands such as capsaicin and is highly sensitive to changes in extracellular pH. In the body core, where temperature is usually stable and capsaicin is normally absent, H+ released in response to ischemia, tissue injury, or inflammation is the best-known endogenous TRPV1 agonist, activating the channel to mediate pain and vasodilation. Paradoxically, removal of H+ elicits a transient increase in TRPV1 current that is much larger than the initial H+-activated current. We found that this prominent OFF response is caused by rapid recovery from H+ inhibition of the excitatory current carried by H+-activated TRPV1 channels. H+ inhibited current by interfering with ion permeation. The degree of inhibition is voltage and permeant ion dependent, and it can be affected but not eliminated by mutations to acidic residues within or near the ion selectivity filter. The opposing H+-mediated gating and permeation effects produce complex current responses under different cellular conditions that are expected to greatly affect the response of nociceptive neurons and other TRPV1-expressing cells.
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Affiliation(s)
- Bo Hyun Lee
- Department of Physiology and Membrane Biology, University of California Davis School of Medicine, Davis, CA 95616
| | - Jie Zheng
- Department of Physiology and Membrane Biology, University of California Davis School of Medicine, Davis, CA 95616
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30
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Hilton JK, Rath P, Helsell CVM, Beckstein O, Van Horn WD. Understanding Thermosensitive Transient Receptor Potential Channels as Versatile Polymodal Cellular Sensors. Biochemistry 2015; 54:2401-13. [DOI: 10.1021/acs.biochem.5b00071] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- Jacob K. Hilton
- Center
for Personalized Diagnostics, Magnetic Resonance Research Center,
and Department of Chemistry and Biochemistry, Arizona State University, 551 East University Drive, PSG-106, Tempe, Arizona 85287, United States
| | - Parthasarathi Rath
- Center
for Personalized Diagnostics, Magnetic Resonance Research Center,
and Department of Chemistry and Biochemistry, Arizona State University, 551 East University Drive, PSG-106, Tempe, Arizona 85287, United States
| | - Cole V. M. Helsell
- Center
for Personalized Diagnostics, Magnetic Resonance Research Center,
and Department of Chemistry and Biochemistry, Arizona State University, 551 East University Drive, PSG-106, Tempe, Arizona 85287, United States
| | - Oliver Beckstein
- Center
for Biological Physics and Department of Physics, Arizona State University, 550 East Tyler Mall, Tempe, Arizona 85287, United States
| | - Wade D. Van Horn
- Center
for Personalized Diagnostics, Magnetic Resonance Research Center,
and Department of Chemistry and Biochemistry, Arizona State University, 551 East University Drive, PSG-106, Tempe, Arizona 85287, United States
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31
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Yu W, Jiang LH, Zheng Y, Hu X, Luo J, Yang W. Inactivation of TRPM2 channels by extracellular divalent copper. PLoS One 2014; 9:e112071. [PMID: 25386648 PMCID: PMC4227687 DOI: 10.1371/journal.pone.0112071] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2014] [Accepted: 10/11/2014] [Indexed: 12/02/2022] Open
Abstract
Cu2+ is an essential metal ion that plays a critical role in the regulation of a number of ion channels and receptors in addition to acting as a cofactor in a variety of enzymes. Here, we showed that human melastatin transient receptor potential 2 (hTRPM2) channel is sensitive to inhibition by extracellular Cu2+. Cu2+ at concentrations as low as 3 µM inhibited the hTRPM2 channel completely and irreversibly upon washing or using Cu2+ chelators, suggesting channel inactivation. The Cu2+-induced inactivation was similar when the channels conducted inward or outward currents, indicating the permeating ions had little effect on Cu2+-induced inactivation. Furthermore, Cu2+ had no effect on singe channel conductance. Alanine substitution by site-directed mutagenesis of His995 in the pore-forming region strongly attenuated Cu2+-induced channel inactivation, and mutation of several other pore residues to alanine altered the kinetics of channel inactivation by Cu2+. In addition, while introduction of the P1018L mutation is known to result in channel inactivation, exposure to Cu2+ accelerated the inactivation of this mutant channel. In contrast with the hTRPM2, the mouse TRPM2 (mTRPM2) channel, which contains glutamine at the position equivalent to His995, was insensitive to Cu2+. Replacement of His995 with glutamine in the hTRPM2 conferred loss of Cu2+-induced channel inactivation. Taken together, these results suggest that Cu2+ inactivates the hTRPM2 channel by interacting with the outer pore region. Our results also indicate that the amino acid residue difference in this region gives rise to species-dependent effect by Cu2+ on the human and mouse TRPM2 channels.
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Affiliation(s)
- Wenyue Yu
- Key Laboratory of Medical Neurobiology of the Ministry of Health of China, Zhejiang Province Key Laboratory of Neurobiology, Department of Neurobiology, School of Medicine, Zhejiang University, Hangzhou, Zhejiang Province, China
| | - Lin-Hua Jiang
- Department of Physiology and Neurobiology, Xinxiang Medical University, Xinxiang, Henan Province, China
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
| | - Yang Zheng
- Key Laboratory of Medical Neurobiology of the Ministry of Health of China, Zhejiang Province Key Laboratory of Neurobiology, Department of Neurobiology, School of Medicine, Zhejiang University, Hangzhou, Zhejiang Province, China
| | - Xupang Hu
- Key Laboratory of Medical Neurobiology of the Ministry of Health of China, Zhejiang Province Key Laboratory of Neurobiology, Department of Neurobiology, School of Medicine, Zhejiang University, Hangzhou, Zhejiang Province, China
| | - Jianhong Luo
- Key Laboratory of Medical Neurobiology of the Ministry of Health of China, Zhejiang Province Key Laboratory of Neurobiology, Department of Neurobiology, School of Medicine, Zhejiang University, Hangzhou, Zhejiang Province, China
- * E-mail: (JHL); (WY)
| | - Wei Yang
- Key Laboratory of Medical Neurobiology of the Ministry of Health of China, Zhejiang Province Key Laboratory of Neurobiology, Department of Neurobiology, School of Medicine, Zhejiang University, Hangzhou, Zhejiang Province, China
- * E-mail: (JHL); (WY)
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32
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Permeation, regulation and control of expression of TRP channels by trace metal ions. Pflugers Arch 2014; 467:1143-64. [PMID: 25106481 PMCID: PMC4435931 DOI: 10.1007/s00424-014-1590-3] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Revised: 07/10/2014] [Accepted: 07/13/2014] [Indexed: 01/26/2023]
Abstract
Transient receptor potential (TRP) channels form a diverse family of cation channels comprising 28 members in mammals. Although some TRP proteins can only be found on intracellular membranes, most of the TRP protein isoforms reach the plasma membrane where they form ion channels and control a wide number of biological processes. There, their involvement in the transport of cations such as calcium and sodium has been well documented. However, a growing number of studies have started to expand our understanding of these proteins by showing that they also transport other biologically relevant metal ions like zinc, magnesium, manganese and cobalt. In addition to this newly recognized property, the activity and expression of TRP channels can be regulated by metal ions like magnesium, gadolinium, lanthanum or cisplatin. The aim of this review is to highlight the complex relationship between metal ions and TRP channels.
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Abstract
Temperature-sensitive transient receptor potential (TRP) ion channels are members of the large tetrameric cation channels superfamily but are considered to be uniquely sensitive to heat, which has been presumed to be due to the existence of an unidentified temperature-sensing domain. Here we report that the homologous voltage-gated potassium (Kv) channels also exhibit high temperature sensitivity comparable to that of TRPV1, which is detectable under specific conditions when the voltage sensor is functionally decoupled from the activation gate through either intrinsic mechanisms or mutations. Interestingly, mutations could tune Shaker channel to be either heat-activated or heat-deactivated. Therefore, high temperature sensitivity is intrinsic to both TRP and Kv channels. Our findings suggest important physiological roles of heat-induced variation in Kv channel activities. Mechanistically our findings indicate that temperature-sensing TRP channels may not contain a specialized heat-sensor domain; instead, non-obligatory allosteric gating permits the intrinsic heat sensitivity to drive channel activation, allowing temperature-sensitive TRP channels to function as polymodal nociceptors. DOI:http://dx.doi.org/10.7554/eLife.03255.001 If you touch something too hot, it can cause you pain and damage your skin. Sensing the heat given off by an object or the temperature of the environment is possible, at least in part, because of proteins called temperature-sensitive TRP ion channels. These proteins are found in the cell membranes of nerve endings that are underneath the skin; and they open in response to heat, allowing ions to flow into the nerve cell. This in turn triggers a nerve impulse that is sent to our central nervous system and is perceived as heat and/or pain. The ability to sense heat was thought to be unique to these TRP ion channels, and it was believed that these ion channels contained an as-yet unidentified temperature-sensing domain. However, Yang and Zheng now report that similar ion channels, which open in response to changes in the voltage that exists across a cell's membrane, are also sensitive to changes in temperature. The temperature response of these ‘voltage-gated channels’ had largely eluded the attention of researchers in the past. This is because parts of the ion channel—which act like a ‘voltage sensor’ and only shift when the membrane voltage changes—normally keep the channel closed and directly open the channel when they move. Like all other proteins, ion channels are made from smaller building blocks called amino acids; and by changing some of the amino acids in the voltage-gated channel Yang and Zheng could decouple these normally linked actions. The changes to the channel meant that it did not immediately open when the voltage sensor moved; and decreasing the concentration of calcium ions inside the cell had the same effect as changing these amino acids. Both approaches revealed that, after a change in membrane voltage caused the voltage sensor to move, the ion channel remained closed until a high temperature caused it to open. Yang and Zheng revealed that the response of the modified voltage-gated channel to temperature was comparable to that of a typical heat-sensitive TRP ion channel. Further experiments showed that replacing some of the amino acids in the voltage-gated potassium ion channel with different amino acids could cause the channel to be either opened or closed by heat. The findings of Yang and Zheng indicate that temperature-sensing TRP channels may not contain a specialized heat-sensor domain. Instead, as these TRP ion channels do not require other parts of the protein to move in order to open the channel, they can be activated by their own inherent sensitivity to heat. DOI:http://dx.doi.org/10.7554/eLife.03255.002
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Affiliation(s)
- Fan Yang
- Department of Physiology and Membrane Biology, University of California, Davis School of Medicine, Davis, United States
| | - Jie Zheng
- Department of Physiology and Membrane Biology, University of California, Davis School of Medicine, Davis, United States
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Jia X, Zhang H, Cao X, Yin Y, Zhang B. Activation of TRPV1 mediates thymic stromal lymphopoietin release via the Ca2+/NFAT pathway in airway epithelial cells. FEBS Lett 2014; 588:3047-54. [PMID: 24931369 DOI: 10.1016/j.febslet.2014.06.018] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2014] [Revised: 05/08/2014] [Accepted: 06/04/2014] [Indexed: 12/22/2022]
Abstract
The airway epithelium is exposed to a range of irritants in the environment that are known to trigger inflammatory response such as asthma. Transient receptor potential vanilloid 1 (TRPV1) is a Ca(2+)-permeable cation channel critical for detecting noxious stimuli by sensory neurons. Recently increasing evidence suggests TRPV1 is also crucially involved in the pathophysiology of asthma on airway epithelium in human. Here we report that in airway epithelial cells TRPV1 activation potently induces allergic cytokine thymic stromal lymphopoietin (TSLP) release. TSLP induction by protease-activated receptor (PAR)-2 activation is also partially mediated by TRPV1 channels.
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Affiliation(s)
- Xinying Jia
- Department of Pathology, Peking University Health Science Center, 100191 Beijing, China
| | - Hong Zhang
- Department of Pathology, Peking University Health Science Center, 100191 Beijing, China
| | - Xu Cao
- Department of Neurology, Peking University Health Science Center, 100191 Beijing, China.
| | - Yuxin Yin
- Department of Pathology, Peking University Health Science Center, 100191 Beijing, China
| | - Bo Zhang
- Department of Pathology, Peking University Health Science Center, 100191 Beijing, China.
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Ma L, Lee BH, Mao R, Cai A, Jia Y, Clifton H, Schaefer S, Xu L, Zheng J. Nicotinic acid activates the capsaicin receptor TRPV1: Potential mechanism for cutaneous flushing. Arterioscler Thromb Vasc Biol 2014; 34:1272-80. [PMID: 24675661 DOI: 10.1161/atvbaha.113.303346] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE Nicotinic acid (also known as niacin or vitamin B3), widely used to treat dyslipidemias, represents an effective and safe means to reduce the risk of mortality from cardiovascular disease. Nonetheless, a substantial fraction of patients discontinue treatment because of a strong side effect of cutaneous vasodilation, commonly termed flushing. In the present study, we tested the hypothesis that nicotinic acid causes flushing partially by activating the capsaicin receptor TRPV1, a polymodal cellular sensor that mediates the flushing response on consumption of spicy food. APPROACH AND RESULTS We observed that the nicotinic acid-induced increase in blood flow was substantially reduced in Trpv1(-/-) knockout mice, indicating involvement of the channel in flushing response. Using exogenously expressed TRPV1, we confirmed that nicotinic acid at submillimolar to millimolar concentrations directly and potently activates TRPV1 from the intracellular side. Binding of nicotinic acid to TRPV1 lowers its activation threshold for heat, causing channel opening at physiological temperatures. The activation of TRPV1 by voltage or ligands (capsaicin and 2-aminoethoxydiphenyl borate) is also potentiated by nicotinic acid. We further demonstrated that nicotinic acid does not compete directly with capsaicin but may activate TRPV1 through the 2-aminoethoxydiphenyl borate activation pathway. Using live-cell fluorescence imaging, we observed that nicotinic acid can quickly enter the cell through a transporter-mediated pathway to activate TRPV1. CONCLUSIONS Direct activation of TRPV1 by nicotinic acid may lead to cutaneous vasodilation that contributes to flushing, suggesting a potential novel pathway to inhibit flushing and to improve compliance.
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Affiliation(s)
- Linlin Ma
- From the Department of Physiology and Membrane Biology (L.M., B.H.L., J.Z.) and Division of Cardiovascular Medicine (H.C., S.S.), University of California School of Medicine, Davis; Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan Province, China (R.M, A.C., Y.J., L.X.); and Institute for Molecular Bioscience, University of Queensland, St Lucia, Queensland, Australia (L.M.)
| | - Bo Hyun Lee
- From the Department of Physiology and Membrane Biology (L.M., B.H.L., J.Z.) and Division of Cardiovascular Medicine (H.C., S.S.), University of California School of Medicine, Davis; Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan Province, China (R.M, A.C., Y.J., L.X.); and Institute for Molecular Bioscience, University of Queensland, St Lucia, Queensland, Australia (L.M.)
| | - Rongrong Mao
- From the Department of Physiology and Membrane Biology (L.M., B.H.L., J.Z.) and Division of Cardiovascular Medicine (H.C., S.S.), University of California School of Medicine, Davis; Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan Province, China (R.M, A.C., Y.J., L.X.); and Institute for Molecular Bioscience, University of Queensland, St Lucia, Queensland, Australia (L.M.)
| | - Anping Cai
- From the Department of Physiology and Membrane Biology (L.M., B.H.L., J.Z.) and Division of Cardiovascular Medicine (H.C., S.S.), University of California School of Medicine, Davis; Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan Province, China (R.M, A.C., Y.J., L.X.); and Institute for Molecular Bioscience, University of Queensland, St Lucia, Queensland, Australia (L.M.)
| | - Yunfang Jia
- From the Department of Physiology and Membrane Biology (L.M., B.H.L., J.Z.) and Division of Cardiovascular Medicine (H.C., S.S.), University of California School of Medicine, Davis; Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan Province, China (R.M, A.C., Y.J., L.X.); and Institute for Molecular Bioscience, University of Queensland, St Lucia, Queensland, Australia (L.M.)
| | - Heather Clifton
- From the Department of Physiology and Membrane Biology (L.M., B.H.L., J.Z.) and Division of Cardiovascular Medicine (H.C., S.S.), University of California School of Medicine, Davis; Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan Province, China (R.M, A.C., Y.J., L.X.); and Institute for Molecular Bioscience, University of Queensland, St Lucia, Queensland, Australia (L.M.)
| | - Saul Schaefer
- From the Department of Physiology and Membrane Biology (L.M., B.H.L., J.Z.) and Division of Cardiovascular Medicine (H.C., S.S.), University of California School of Medicine, Davis; Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan Province, China (R.M, A.C., Y.J., L.X.); and Institute for Molecular Bioscience, University of Queensland, St Lucia, Queensland, Australia (L.M.)
| | - Lin Xu
- From the Department of Physiology and Membrane Biology (L.M., B.H.L., J.Z.) and Division of Cardiovascular Medicine (H.C., S.S.), University of California School of Medicine, Davis; Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan Province, China (R.M, A.C., Y.J., L.X.); and Institute for Molecular Bioscience, University of Queensland, St Lucia, Queensland, Australia (L.M.)
| | - Jie Zheng
- From the Department of Physiology and Membrane Biology (L.M., B.H.L., J.Z.) and Division of Cardiovascular Medicine (H.C., S.S.), University of California School of Medicine, Davis; Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan Province, China (R.M, A.C., Y.J., L.X.); and Institute for Molecular Bioscience, University of Queensland, St Lucia, Queensland, Australia (L.M.).
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Abstract
Temperature-sensitive transient receptor potential (TRP) channels are structurally similar to other tetrameric cation channels, but can be potently activated by heat. Recent studies suggest that the pore-forming region directly participates in activation gating. In this chapter, we summarize major findings from both structural and functional studies concerning the gating role of the pore region, focusing in particular on TRPV1. The emerging picture is that the peripheral S1-S4 region of TRPV1 is rigid and plays a supporting role for the pore to undergo conformational rearrangements. This places the pore region in the center of activation gating.
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Yang F, Ma L, Cao X, Wang K, Zheng J. Divalent cations activate TRPV1 through promoting conformational change of the extracellular region. ACTA ACUST UNITED AC 2013; 143:91-103. [PMID: 24344245 PMCID: PMC3874565 DOI: 10.1085/jgp.201311024] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Divalent cations Mg2+ and Ba2+ selectively and directly potentiate transient receptor potential vanilloid type 1 heat activation by lowering the activation threshold into the room temperature range. We found that Mg2+ potentiates channel activation only from the extracellular side; on the intracellular side, Mg2+ inhibits channel current. By dividing the extracellularly accessible region of the channel protein into small segments and perturbing the structure of each segment with sequence replacement mutations, we observed that the S1–S2 linker, the S3–S4 linker, and the pore turret are all required for Mg2+ potentiation. Sequence replacements at these regions substantially reduced or eliminated Mg2+-induced activation at room temperature while sparing capsaicin activation. Heat activation was affected by many, but not all, of these structural alternations. These observations indicate that extracellular linkers and the turret may interact with each other. Site-directed fluorescence resonance energy transfer measurements further revealed that, like heat, Mg2+ also induces structural changes in the pore turret. Interestingly, turret movement induced by Mg2+ precedes channel activation, suggesting that Mg2+-induced conformational change in the extracellular region most likely serves as the cause of channel activation instead of a coincidental or accommodating structural adjustment.
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Affiliation(s)
- Fan Yang
- Department of Physiology and Membrane Biology, University of California School of Medicine, Davis, Davis, CA 95616
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