1
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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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2
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Fischer MJM, Ciotu CI, Szallasi A. The Mysteries of Capsaicin-Sensitive Afferents. Front Physiol 2020; 11:554195. [PMID: 33391007 PMCID: PMC7772409 DOI: 10.3389/fphys.2020.554195] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Accepted: 11/13/2020] [Indexed: 12/11/2022] Open
Abstract
A fundamental subdivision of nociceptive sensory neurons is named after their unique sensitivity to capsaicin, the pungent ingredient in hot chili peppers: these are the capsaicin-sensitive afferents. The initial excitation by capsaicin of these neurons manifested as burning pain sensation is followed by a lasting refractory state, traditionally referred to as "capsaicin desensitization," during which the previously excited neurons are unresponsive not only to capsaicin but a variety of unrelated stimuli including noxious heat. The long sought-after capsaicin receptor, now known as TRPV1 (transient receptor potential cation channel, subfamily V member 1), was cloned more than two decades ago. The substantial reduction of the inflammatory phenotype of Trpv1 knockout mice has spurred extensive efforts in the pharmaceutical industry to develop small molecule TRPV1 antagonists. However, adverse effects, most importantly hyperthermia and burn injuries, have so far prevented any compounds from progressing beyond Phase 2. There is increasing evidence that these limitations can be at least partially overcome by approaches outside of the mainstream pharmaceutical development, providing novel therapeutic options through TRPV1. Although ablation of the whole TRPV1-expressing nerve population by high dose capsaicin, or more selectively by intersectional genetics, has allowed researchers to investigate the functions of capsaicin-sensitive afferents in health and disease, several "mysteries" remain unsolved to date, including the molecular underpinnings of "capsaicin desensitization," and the exact role these nerves play in thermoregulation and heat sensation. This review tries to shed some light on these capsaicin mechanisms.
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Affiliation(s)
- Michael J. M. Fischer
- Center of Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Cosmin I. Ciotu
- Center of Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Arpad Szallasi
- 1st Department of Pathology and Experimental Cancer Research, Semmelweis University, Budapest, Hungary
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3
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Faris P, Ferulli F, Vismara M, Tanzi M, Negri S, Rumolo A, Lefkimmiatis K, Maestri M, Shekha M, Pedrazzoli P, Guidetti GF, Montagna D, Moccia F. Hydrogen Sulfide-Evoked Intracellular Ca 2+ Signals in Primary Cultures of Metastatic Colorectal Cancer Cells. Cancers (Basel) 2020; 12:cancers12113338. [PMID: 33187307 PMCID: PMC7696676 DOI: 10.3390/cancers12113338] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Revised: 11/05/2020] [Accepted: 11/06/2020] [Indexed: 02/07/2023] Open
Abstract
Simple Summary Colorectal cancer (CRC) is the most common type of gastrointestinal cancer and the third most predominant cancer in the world. CRC is potentially curable with surgical resection of the primary tumor. The clinical problem of colorectal cancer, however, is the spread and outgrowth of metastases, which are difficult to eradicate and lead to a patient’s death. The failure of conventional treatment to significantly improved outcomes in mCRC has prompted the search for alternative molecular targets with the goal of ameliorating the prognosis of these patients. The present investigation revealed that exogenous delivery of hydrogen sulfide (H2S) suppresses proliferation in metastatic colorectal cancer cells by inducing an increase in intracellular Ca2+ concentration. H2S was effective on metastatic, but not normal, cells. Therefore, we propose that exogenous administration of H2S to patients affected by metastatic colorectal carcinoma could represent a promising therapeutic alternative. Abstract Exogenous administration of hydrogen sulfide (H2S) is emerging as an alternative anticancer treatment. H2S-releasing compounds have been shown to exert a strong anticancer effect by suppressing proliferation and/or inducing apoptosis in several cancer cell types, including colorectal carcinoma (CRC). The mechanism whereby exogenous H2S affects CRC cell proliferation is yet to be clearly elucidated, but it could involve an increase in intracellular Ca2+ concentration ([Ca2+]i). Herein, we sought to assess for the first time whether (and how) sodium hydrosulfide (NaHS), one of the most widely employed H2S donors, induced intracellular Ca2+ signals in primary cultures of human metastatic CRC (mCRC) cells. We provided the evidence that NaHS induced extracellular Ca2+ entry in mCRC cells by activating the Ca2+-permeable channel Transient Receptor Potential Vanilloid 1 (TRPV1) followed by the Na+-dependent recruitment of the reverse-mode of the Na+/Ca2+ (NCX) exchanger. In agreement with these observations, TRPV1 protein was expressed and capsaicin, a selective TRPV1 agonist, induced Ca2+ influx by engaging both TRPV1 and NCX in mCRC cells. Finally, NaHS reduced mCRC cell proliferation, but did not promote apoptosis or aberrant mitochondrial depolarization. These data support the notion that exogenous administration of H2S may prevent mCRC cell proliferation through an increase in [Ca2+]i, which is triggered by TRPV1.
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Affiliation(s)
- Pawan Faris
- Laboratory of General Physiology, Department of Biology and Biotechnology “L. Spallanzani”, University of Pavia, 27100 Pavia, Italy; (P.F.); (S.N.)
- Department of Biology, Cihan University-Erbil, 44001 Erbil, Iraq
| | - Federica Ferulli
- Laboratory of Immunology Transplantation, Foundation IRCCS Policlinico San Matteo, 27100 Pavia, Italy; (F.F.); (M.T.); (A.R.)
| | - Mauro Vismara
- Laboratory of Biochemistry, Department of Biology and Biotechnology “L. Spallanzani”, University of Pavia, 27100 Pavia, Italy; (M.V.); (G.F.G.)
| | - Matteo Tanzi
- Laboratory of Immunology Transplantation, Foundation IRCCS Policlinico San Matteo, 27100 Pavia, Italy; (F.F.); (M.T.); (A.R.)
| | - Sharon Negri
- Laboratory of General Physiology, Department of Biology and Biotechnology “L. Spallanzani”, University of Pavia, 27100 Pavia, Italy; (P.F.); (S.N.)
| | - Agnese Rumolo
- Laboratory of Immunology Transplantation, Foundation IRCCS Policlinico San Matteo, 27100 Pavia, Italy; (F.F.); (M.T.); (A.R.)
| | - Kostantinos Lefkimmiatis
- Department of Molecular Medicine, University of Pavia, 27100 Pavia, Italy;
- Veneto Institute of Molecular Medicine, Foundation for Advanced Biomedical Research, 35131 Padua, Italy
| | - Marcello Maestri
- Medical Surgery, Foundation IRCCS Policlinico San Matteo, 27100 Pavia, Italy;
| | - Mudhir Shekha
- Faculty of Science, Department of Medical Analysis, Tishk International University-Erbil, 44001 Erbil, Iraq;
| | - Paolo Pedrazzoli
- Medical Oncology, Foundation IRCCS Policlinico San Matteo, 27100 Pavia, Italy;
| | - Gianni Francesco Guidetti
- Laboratory of Biochemistry, Department of Biology and Biotechnology “L. Spallanzani”, University of Pavia, 27100 Pavia, Italy; (M.V.); (G.F.G.)
| | - Daniela Montagna
- Laboratory of Immunology Transplantation, Foundation IRCCS Policlinico San Matteo, 27100 Pavia, Italy; (F.F.); (M.T.); (A.R.)
- Diagnostic and Pediatric, Department of Sciences Clinic-Surgical, University of Pavia, 27100 Pavia, Italy
- Correspondence: (D.M.); (F.M.); Tel.: +39-382-987-619 (F.M.)
| | - Francesco Moccia
- Laboratory of General Physiology, Department of Biology and Biotechnology “L. Spallanzani”, University of Pavia, 27100 Pavia, Italy; (P.F.); (S.N.)
- Correspondence: (D.M.); (F.M.); Tel.: +39-382-987-619 (F.M.)
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4
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Toft-Bertelsen TL, Yarishkin O, Redmon S, Phuong TTT, Križaj D, MacAulay N. Volume sensing in the transient receptor potential vanilloid 4 ion channel is cell type-specific and mediated by an N-terminal volume-sensing domain. J Biol Chem 2019; 294:18421-18434. [PMID: 31619514 DOI: 10.1074/jbc.ra119.011187] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Revised: 10/11/2019] [Indexed: 12/29/2022] Open
Abstract
Many retinal diseases are associated with pathological cell swelling, but the underlying etiology remains to be established. A key component of the volume-sensitive machinery, the transient receptor potential vanilloid 4 (TRPV4) ion channel, may represent a sensor and transducer of cell swelling, but the molecular link between the swelling and TRPV4 activation is unresolved. Here, our results from experiments using electrophysiology, cell volumetric measurements, and fluorescence imaging conducted in murine retinal cells and Xenopus oocytes indicated that cell swelling in the physiological range activated TRPV4 in Müller glia and Xenopus oocytes, but required phospholipase A2 (PLA2) activity exclusively in Müller cells. Volume-dependent TRPV4 gating was independent of cytoskeletal rearrangements and phosphorylation. Our findings also revealed that TRPV4-mediated transduction of volume changes is dependent by its N terminus, more specifically by its distal-most part. We conclude that the volume sensitivity and function of TRPV4 in situ depend critically on its functional and cell type-specific interactions.
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Affiliation(s)
- Trine L Toft-Bertelsen
- Department of Neuroscience, University of Copenhagen, Blegdamsvej 3, Bldg. 24.6, 2200 Copenhagen N, Denmark
| | - Oleg Yarishkin
- Department of Ophthalmology and Visual Sciences, University of Utah School of Medicine, Salt Lake City, Utah 84132
| | - Sarah Redmon
- Department of Ophthalmology and Visual Sciences, University of Utah School of Medicine, Salt Lake City, Utah 84132
| | - Tam T T Phuong
- Department of Ophthalmology and Visual Sciences, University of Utah School of Medicine, Salt Lake City, Utah 84132
| | - David Križaj
- Department of Ophthalmology and Visual Sciences, University of Utah School of Medicine, Salt Lake City, Utah 84132.
| | - Nanna MacAulay
- Department of Neuroscience, University of Copenhagen, Blegdamsvej 3, Bldg. 24.6, 2200 Copenhagen N, Denmark.
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5
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Persistent Na+ influx drives L-type channel resting Ca2+ entry in rat melanotrophs. Cell Calcium 2019; 79:11-19. [DOI: 10.1016/j.ceca.2019.02.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Revised: 02/04/2019] [Accepted: 02/04/2019] [Indexed: 11/19/2022]
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6
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Jardín I, López JJ, Diez R, Sánchez-Collado J, Cantonero C, Albarrán L, Woodard GE, Redondo PC, Salido GM, Smani T, Rosado JA. TRPs in Pain Sensation. Front Physiol 2017. [PMID: 28649203 PMCID: PMC5465271 DOI: 10.3389/fphys.2017.00392] [Citation(s) in RCA: 86] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
According to the International Association for the Study of Pain (IASP) pain is characterized as an "unpleasant sensory and emotional experience associated with actual or potential tissue damage". The TRP super-family, compressing up to 28 isoforms in mammals, mediates a myriad of physiological and pathophysiological processes, pain among them. TRP channel might be constituted by similar or different TRP subunits, which will result in the formation of homomeric or heteromeric channels with distinct properties and functions. In this review we will discuss about the function of TRPs in pain, focusing on TRP channles that participate in the transduction of noxious sensation, especially TRPV1 and TRPA1, their expression in nociceptors and their sensitivity to a large number of physical and chemical stimuli.
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Affiliation(s)
- Isaac Jardín
- Cell Physiology Research Group, Department of Physiology, University of ExtremaduraCáceres, Spain
| | - José J López
- Cell Physiology Research Group, Department of Physiology, University of ExtremaduraCáceres, Spain
| | - Raquel Diez
- Cell Physiology Research Group, Department of Physiology, University of ExtremaduraCáceres, Spain
| | - José Sánchez-Collado
- Cell Physiology Research Group, Department of Physiology, University of ExtremaduraCáceres, Spain
| | - Carlos Cantonero
- Cell Physiology Research Group, Department of Physiology, University of ExtremaduraCáceres, Spain
| | - Letizia Albarrán
- Cell Physiology Research Group, Department of Physiology, University of ExtremaduraCáceres, Spain
| | - Geoffrey E Woodard
- Department of Surgery, Uniformed Services University of the Health SciencesBethesda, MD, United States
| | - Pedro C Redondo
- Cell Physiology Research Group, Department of Physiology, University of ExtremaduraCáceres, Spain
| | - Ginés M Salido
- Cell Physiology Research Group, Department of Physiology, University of ExtremaduraCáceres, Spain
| | - Tarik Smani
- Department of Medical Physiology and Biophysics, Institute of Biomedicine of Sevilla, University of SevilleSevilla, Spain
| | - Juan A Rosado
- Cell Physiology Research Group, Department of Physiology, University of ExtremaduraCáceres, Spain
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7
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Zhao R, Tsang SY. Versatile Roles of Intracellularly Located TRPV1 Channel. J Cell Physiol 2017; 232:1957-1965. [DOI: 10.1002/jcp.25704] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Accepted: 11/22/2016] [Indexed: 12/17/2022]
Affiliation(s)
- Rui Zhao
- School of Life Sciences; The Chinese University of Hong Kong; Hong Kong SAR China
| | - Suk Ying Tsang
- School of Life Sciences; The Chinese University of Hong Kong; Hong Kong SAR China
- State Key Laboratory of Agrobiotechnology; The Chinese University of Hong Kong; Hong Kong SAR China
- Key Laboratory for Regenerative Medicine, Ministry of Education; The Chinese University of Hong Kong; Hong Kong SAR China
- Centre for Novel Biomaterials; The Chinese University of Hong Kong; Hong Kong SAR China
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8
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Wu L, Oshima T, Shan J, Sei H, Tomita T, Ohda Y, Fukui H, Watari J, Miwa H. PAR-2 activation enhances weak acid-induced ATP release through TRPV1 and ASIC sensitization in human esophageal epithelial cells. Am J Physiol Gastrointest Liver Physiol 2015; 309:G695-702. [PMID: 26294672 DOI: 10.1152/ajpgi.00162.2015] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Accepted: 08/10/2015] [Indexed: 01/31/2023]
Abstract
Esophageal visceral hypersensitivity has been proposed to be the pathogenesis of heartburn sensation in nonerosive reflux disease. Protease-activated receptor-2 (PAR-2) is expressed in human esophageal epithelial cells and is believed to play a role in inflammation and sensation. PAR-2 activation may modulate these responses through adenosine triphosphate (ATP) release, which is involved in transduction of sensation and pain. The transient receptor potential vanilloid receptor 1 (TRPV1) and acid-sensing ion channels (ASICs) are both acid-sensitive nociceptors. However, the interaction among these molecules and the mechanisms of heartburn sensation are still not clear. We therefore examined whether ATP release in human esophageal epithelial cells in response to acid is modulated by TRPV1 and ASICs and whether PAR-2 activation influences the sensitivity of TRPV1 and ASICs. Weak acid (pH 5) stimulated the release of ATP from primary human esophageal epithelial cells (HEECs). This effect was significantly reduced after pretreatment with 5-iodoresiniferatoxin (IRTX), a TRPV1-specific antagonist, or with amiloride, a nonselective ASIC blocker. TRPV1 and ASIC3 small interfering RNA (siRNA) transfection also decreased weak acid-induced ATP release. Pretreatment of HEECs with trypsin, tryptase, or a PAR-2 agonist enhanced weak acid-induced ATP release. Trypsin treatment led to the phosphorylation of TRPV1. Acid-induced ATP release enhancement by trypsin was partially blocked by IRTX, amiloride, or a PAR-2 antagonist. Conversely, acid-induced ATP release was augmented by PAR-2 activation through TRPV1 and ASICs. These findings suggested that the pathophysiology of heartburn sensation or esophageal hypersensitivity may be associated with the activation of PAR-2, TRPV1, and ASICs.
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Affiliation(s)
- Liping Wu
- Division of Gastroenterology, Department of Internal Medicine, Hyogo College of Medicine, Nishinomiya, Japan; and Department of Gastroenterology, The Third People's Hospital of Chengdu, Chengdu, China
| | - Tadayuki Oshima
- Division of Gastroenterology, Department of Internal Medicine, Hyogo College of Medicine, Nishinomiya, Japan; and
| | - Jing Shan
- Division of Gastroenterology, Department of Internal Medicine, Hyogo College of Medicine, Nishinomiya, Japan; and Department of Gastroenterology, The Third People's Hospital of Chengdu, Chengdu, China
| | - Hiroo Sei
- Division of Gastroenterology, Department of Internal Medicine, Hyogo College of Medicine, Nishinomiya, Japan; and
| | - Toshihiko Tomita
- Division of Gastroenterology, Department of Internal Medicine, Hyogo College of Medicine, Nishinomiya, Japan; and
| | - Yoshio Ohda
- Division of Gastroenterology, Department of Internal Medicine, Hyogo College of Medicine, Nishinomiya, Japan; and
| | - Hirokazu Fukui
- Division of Gastroenterology, Department of Internal Medicine, Hyogo College of Medicine, Nishinomiya, Japan; and
| | - Jiro Watari
- Division of Gastroenterology, Department of Internal Medicine, Hyogo College of Medicine, Nishinomiya, Japan; and
| | - Hiroto Miwa
- Division of Gastroenterology, Department of Internal Medicine, Hyogo College of Medicine, Nishinomiya, Japan; and
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9
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Zaelzer C, Hua P, Prager-Khoutorsky M, Ciura S, Voisin D, Liedtke W, Bourque C. ΔN-TRPV1: A Molecular Co-detector of Body Temperature and Osmotic Stress. Cell Rep 2015; 13:23-30. [DOI: 10.1016/j.celrep.2015.08.061] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2014] [Revised: 07/25/2015] [Accepted: 08/21/2015] [Indexed: 10/23/2022] Open
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10
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Polymodal Transient Receptor Potential Vanilloid (TRPV) Ion Channels in Chondrogenic Cells. Int J Mol Sci 2015; 16:18412-38. [PMID: 26262612 PMCID: PMC4581253 DOI: 10.3390/ijms160818412] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Revised: 07/03/2015] [Accepted: 07/07/2015] [Indexed: 12/17/2022] Open
Abstract
Mature and developing chondrocytes exist in a microenvironment where mechanical load, changes of temperature, osmolarity and acidic pH may influence cellular metabolism. Polymodal Transient Receptor Potential Vanilloid (TRPV) receptors are environmental sensors mediating responses through activation of linked intracellular signalling pathways. In chondrogenic high density cultures established from limb buds of chicken and mouse embryos, we identified TRPV1, TRPV2, TRPV3, TRPV4 and TRPV6 mRNA expression with RT-PCR. In both cultures, a switch in the expression pattern of TRPVs was observed during cartilage formation. The inhibition of TRPVs with the non-selective calcium channel blocker ruthenium red diminished chondrogenesis and caused significant inhibition of proliferation. Incubating cell cultures at 41 °C elevated the expression of TRPV1, and increased cartilage matrix production. When chondrogenic cells were exposed to mechanical load at the time of their differentiation into matrix producing chondrocytes, we detected increased mRNA levels of TRPV3. Our results demonstrate that developing chondrocytes express a full palette of TRPV channels and the switch in the expression pattern suggests differentiation stage-dependent roles of TRPVs during cartilage formation. As TRPV1 and TRPV3 expression was altered by thermal and mechanical stimuli, respectively, these are candidate channels that contribute to the transduction of environmental stimuli in chondrogenic cells.
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11
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Quallo T, Vastani N, Horridge E, Gentry C, Parra A, Moss S, Viana F, Belmonte C, Andersson DA, Bevan S. TRPM8 is a neuronal osmosensor that regulates eye blinking in mice. Nat Commun 2015; 6:7150. [PMID: 25998021 PMCID: PMC4455064 DOI: 10.1038/ncomms8150] [Citation(s) in RCA: 97] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2014] [Accepted: 04/13/2015] [Indexed: 01/23/2023] Open
Abstract
Specific peripheral sensory neurons respond to increases in extracellular osmolality but the mechanism responsible for excitation is unknown. Here we show that small increases in osmolality excite isolated mouse dorsal root ganglion (DRG) and trigeminal ganglion (TG) neurons expressing the cold-sensitive TRPM8 channel (transient receptor potential channel, subfamily M, member 8). Hyperosmotic responses were abolished by TRPM8 antagonists, and were absent in DRG and TG neurons isolated from Trpm8(-/-) mice. Heterologously expressed TRPM8 was activated by increased osmolality around physiological levels and inhibited by reduced osmolality. Electrophysiological studies in a mouse corneal preparation demonstrated that osmolality regulated the electrical activity of TRPM8-expressing corneal afferent neurons. Finally, the frequency of eye blinks was reduced in Trpm8(-/-) compared with wild-type mice and topical administration of a TRPM8 antagonist reduced blinking in wild-type mice. Our findings identify TRPM8 as a peripheral osmosensor responsible for the regulation of normal eye-blinking in mice.
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Affiliation(s)
- Talisia Quallo
- Wolfson Centre for Age Related Diseases, King's College London, London SE1 1UL, UK
| | - Nisha Vastani
- Wolfson Centre for Age Related Diseases, King's College London, London SE1 1UL, UK
| | - Elisabeth Horridge
- Wolfson Centre for Age Related Diseases, King's College London, London SE1 1UL, UK
| | - Clive Gentry
- Wolfson Centre for Age Related Diseases, King's College London, London SE1 1UL, UK
| | - Andres Parra
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-CSIC, San Juan de Alicante E-03550, Spain
| | - Sian Moss
- Wolfson Centre for Age Related Diseases, King's College London, London SE1 1UL, UK
| | - Felix Viana
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-CSIC, San Juan de Alicante E-03550, Spain
| | - Carlos Belmonte
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-CSIC, San Juan de Alicante E-03550, Spain
| | - David A. Andersson
- Wolfson Centre for Age Related Diseases, King's College London, London SE1 1UL, UK
| | - Stuart Bevan
- Wolfson Centre for Age Related Diseases, King's College London, London SE1 1UL, UK
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12
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Full-length transient receptor potential vanilloid 1 channels mediate calcium signals and possibly contribute to osmoreception in vasopressin neurones in the rat supraoptic nucleus. Cell Calcium 2015; 57:25-37. [DOI: 10.1016/j.ceca.2014.11.003] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2014] [Revised: 11/06/2014] [Accepted: 11/10/2014] [Indexed: 11/19/2022]
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13
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Abstract
TRPV1 is a well-characterised channel expressed by a subset of peripheral sensory neurons involved in pain sensation and also at a number of other neuronal and non-neuronal sites in the mammalian body. Functionally, TRPV1 acts as a sensor for noxious heat (greater than ~42 °C). It can also be activated by some endogenous lipid-derived molecules, acidic solutions (pH < 6.5) and some pungent chemicals and food ingredients such as capsaicin, as well as by toxins such as resiniferatoxin and vanillotoxins. Structurally, TRPV1 subunits have six transmembrane (TM) domains with intracellular N- (containing 6 ankyrin-like repeats) and C-termini and a pore region between TM5 and TM6 containing sites that are important for channel activation and ion selectivity. The N- and C- termini have residues and regions that are sites for phosphorylation/dephosphorylation and PI(4,5)P2 binding, which regulate TRPV1 sensitivity and membrane insertion. The channel has several interacting proteins, some of which (e.g. AKAP79/150) are important for TRPV1 phosphorylation. Four TRPV1 subunits form a non-selective, outwardly rectifying ion channel permeable to monovalent and divalent cations with a single-channel conductance of 50-100 pS. TRPV1 channel kinetics reveal multiple open and closed states, and several models for channel activation by voltage, ligand binding and temperature have been proposed. Studies with TRPV1 agonists and antagonists and Trpv1 (-/-) mice have suggested a role for TRPV1 in pain, thermoregulation and osmoregulation, as well as in cough and overactive bladder. TRPV1 antagonists have advanced to clinical trials where findings of drug-induced hyperthermia and loss of heat sensitivity have raised questions about the viability of this therapeutic approach.
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14
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Nilius B, Szallasi A. Transient Receptor Potential Channels as Drug Targets: From the Science of Basic Research to the Art of Medicine. Pharmacol Rev 2014; 66:676-814. [DOI: 10.1124/pr.113.008268] [Citation(s) in RCA: 348] [Impact Index Per Article: 34.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
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15
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Voronova IP, Tuzhikova AA, Kozyreva TV. Expression of Genes for Temperature-Sensitive TRP Channels in the Rat Hypothalamus in Normal Conditions and on Adaptation to Cold. ACTA ACUST UNITED AC 2014. [DOI: 10.1007/s11055-014-9952-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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16
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Wilhelmsen K, Khakpour S, Tran A, Sheehan K, Schumacher M, Xu F, Hellman J. The endocannabinoid/endovanilloid N-arachidonoyl dopamine (NADA) and synthetic cannabinoid WIN55,212-2 abate the inflammatory activation of human endothelial cells. J Biol Chem 2014; 289:13079-100. [PMID: 24644287 DOI: 10.1074/jbc.m113.536953] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Although cannabinoids, such as Δ(9)-tetrahydrocannabinol, have been studied extensively for their psychoactive effects, it has become apparent that certain cannabinoids possess immunomodulatory activity. Endothelial cells (ECs) are centrally involved in the pathogenesis of organ injury in acute inflammatory disorders, such as sepsis, because they express cytokines and chemokines, which facilitate the trafficking of leukocytes to organs, and they modulate vascular barrier function. In this study, we find that primary human ECs from multiple organs express the cannabinoid receptors CB1R, GPR18, and GPR55, as well as the ion channel transient receptor potential cation channel vanilloid type 1. In contrast to leukocytes, CB2R is only minimally expressed in some EC populations. Furthermore, we show that ECs express all of the known endocannabinoid (eCB) metabolic enzymes. Examining a panel of cannabinoids, we demonstrate that the synthetic cannabinoid WIN55,212-2 and the eCB N-arachidonoyl dopamine (NADA), but neither anandamide nor 2-arachidonoylglycerol, reduce EC inflammatory responses induced by bacterial lipopeptide, LPS, and TNFα. We find that endothelial CB1R/CB2R are necessary for the effects of NADA, but not those of WIN55,212-2. Furthermore, transient receptor potential cation channel vanilloid type 1 appears to counter the anti-inflammatory properties of WIN55,212-2 and NADA, but conversely, in the absence of these cannabinoids, its inhibition exacerbates the inflammatory response in ECs activated with LPS. These data indicate that the eCB system can modulate inflammatory activation of the endothelium and may have important implications for a variety of acute inflammatory disorders that are characterized by EC activation.
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Zavala K, Lee J, Chong J, Sharma M, Eilers H, Schumacher MA. The anticancer antibiotic mithramycin-A inhibits TRPV1 expression in dorsal root ganglion neurons. Neurosci Lett 2014; 578:211-6. [PMID: 24468003 DOI: 10.1016/j.neulet.2014.01.021] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2013] [Revised: 01/13/2014] [Accepted: 01/14/2014] [Indexed: 12/17/2022]
Abstract
Activation of peripheral nociceptors by products of inflammation has been shown to be dependent on specific sensory transducing elements such as the capsaicin receptor, TRPV1. The development of high-affinity antagonists to TRPV1 as well as to other receptors capable of detecting noxious stimuli has now become a major focus in analgesic development. Another critical feature of nociception is the relative abundance of a particular pain transducing receptor under normal or pathophysiologic conditions. Increases in expression and/or changes in distribution of nociceptive receptors such as TRPV1 have been correlated with progression of tissue injury and persistence of pain behaviors. Although some details are emerging as to what regulates nociceptor-specific gene expression, compounds that could potentially be used to block or reverse over-expression of nociceptive gene expression are essentially absent. In our efforts to better understand the transcriptional regulation of TRPV1 in sensory neurons, we identified an anticancer agent, mithramycin-A, that decreased TRPV1 expression in primary rat dorsal root ganglion (DRG) neurons. Mithramycin-A dose-dependently (10-50 nM) decreased endogenous TRPV1 mRNA content and appeared to decrease TRPV1-like protein expression in DRG neurons. We also observed that mithramycin-A directed a decrease in the number of capsaicin-responsive DRG neurons without a significant change in the capsaicin-response magnitudes. Interestingly, mithramycin-A also reduced the mRNA encoding Sp1 and Sp4 in DRG neurons, transcription factors previously found to positively regulate TRPV1 expression in sensory neurons. Taken together, we propose that mithramycin-A directs an inhibitory effect on a subpopulation of capsaicin-responsive DRG neurons that utilize Sp1-like factors for TRPV1 expression. Given the therapeutic correlate of mithramycin-A effectiveness in the treatment of certain cancers, small molecule transcriptional inhibitors such as mithramycin-A may serve as useful tools of discovery in pain transduction and possibly future analgesic development.
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Affiliation(s)
- K Zavala
- Department of Anesthesia and Perioperative Care, Division of Pain Medicine, University of California, San Francisco 94143-0427, United States
| | - J Lee
- Department of Anesthesia and Perioperative Care, Division of Pain Medicine, University of California, San Francisco 94143-0427, United States
| | - J Chong
- Department of Anesthesia and Perioperative Care, Division of Pain Medicine, University of California, San Francisco 94143-0427, United States
| | - M Sharma
- Department of Anesthesia and Perioperative Care, Division of Pain Medicine, University of California, San Francisco 94143-0427, United States
| | - H Eilers
- Department of Anesthesia and Perioperative Care, Division of Pain Medicine, University of California, San Francisco 94143-0427, United States
| | - M A Schumacher
- Department of Anesthesia and Perioperative Care, Division of Pain Medicine, University of California, San Francisco 94143-0427, United States.
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Schumacher M, Pasvankas G. Topical capsaicin formulations in the management of neuropathic pain. PROGRESS IN DRUG RESEARCH. FORTSCHRITTE DER ARZNEIMITTELFORSCHUNG. PROGRES DES RECHERCHES PHARMACEUTIQUES 2014; 68:105-128. [PMID: 24941666 DOI: 10.1007/978-3-0348-0828-6_4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
This chapter reviews the scientific and clinical evidence supporting the use of topical formulations containing the pungent principle of chili peppers--capsaicin, for the treatment of peripheral neuropathic pain. Given the limitations of current oral and parenteral therapies for the management of pain arising from various forms of nerve injury, alternate therapeutic approaches that are not associated with systemic adverse events that limit quality of life, impair function, or threaten respiratory depression are critically needed. Moreover, neuropathic conditions can be complicated by progressive changes in the central and peripheral nervous system, leading to persistent reorganization of pain pathways and chronic neuropathic pain. Recent advances in the use of high-dose topical capsaicin preparations hold promise in managing a wide range of painful conditions associated with peripheral neuropathies and may in fact help reduce suffering by reversing progressive changes in the nervous system associated with chronic neuropathic pain conditions.
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Tóth A, Czikora A, Pásztor ET, Dienes B, Bai P, Csernoch L, Rutkai I, Csató V, Mányiné IS, Pórszász R, Edes I, Papp Z, Boczán J. Vanilloid receptor-1 (TRPV1) expression and function in the vasculature of the rat. J Histochem Cytochem 2013; 62:129-44. [PMID: 24217926 DOI: 10.1369/0022155413513589] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Transient receptor potential (TRP) cation channels are emerging in vascular biology. In particular, the expression of the capsaicin receptor (TRPV1) was reported in vascular smooth muscle cells. This study characterized the arteriolar TRPV1 function and expression in the rat. TRPV1 mRNA was expressed in various vascular beds. Six commercially available antibodies were tested for TRPV1 specificity. Two of them were specific (immunostaining was abolished by blocking peptides) for neuronal TRPV1 and one recognized vascular TRPV1. TRPV1 was expressed in blood vessels in the skeletal muscle, mesenteric and skin tissues, as well as in the aorta and carotid arteries. TRPV1 expression was found to be regulated at the level of individual blood vessels, where some vessels expressed, while others did not express TRPV1 in the same tissue sections. Capsaicin (a TRPV1 agonist) evoked constrictions in skeletal muscle arteries and in the carotid artery, but had no effect on the femoral and mesenteric arteries or the aorta. In blood vessels, TRPV1 expression was detected in most of the large arteries, but there were striking differences at level of the small arteries. TRPV1 activity was suppressed in some isolated arteries. This tightly regulated expression and function suggests a physiological role for vascular TRPV1.
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Affiliation(s)
- Attila Tóth
- Division of Clinical Physiology, Institute of Cardiology, University of Debrecen, Debrecen, Hungary (AT, AC, ETP, IR, ISM, IE, IE, ZP)
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Donnerer J, Liebmann I. The Pain Pathway in the Rat following Noxious Thermal Stimulation: Effect of Morphine on pERK1/2 and TRPV1 at the Dorsal Horn Level, and on Hyperalgesia. Pharmacology 2013; 92:32-8. [DOI: 10.1159/000353141] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2013] [Accepted: 05/17/2013] [Indexed: 12/11/2022]
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Avelino A, Charrua A, Frias B, Cruz C, Boudes M, de Ridder D, Cruz F. Transient receptor potential channels in bladder function. Acta Physiol (Oxf) 2013; 207:110-22. [PMID: 23113869 DOI: 10.1111/apha.12021] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2012] [Revised: 01/27/2012] [Accepted: 09/10/2012] [Indexed: 01/17/2023]
Abstract
The transient receptor potential (TRP) superfamily of cationic ion channels includes proteins involved in the transduction of several physical and chemical stimuli to finely tune physiological functions. In the urinary bladder, they are highly expressed in, but not restricted to, primary afferent neurons. The urothelium and some interstitial cells also express several TRP channels. In this review, we describe the expression and the known roles of some members of TRP subfamilies, namely TRPV, TRPM and TRPA, in the urinary bladder. The therapeutic interest of modulating the activity of TRP channels to treat bladder dysfunctions is also discussed.
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Affiliation(s)
- A. Avelino
- Department of Experimental Biology; Faculty of Medicine of University of Porto; Porto; Portugal
| | | | | | | | | | - D. de Ridder
- Department of Molecular Cell Biology; Laboratory Ion Channel Research; KU Leuven; Leuven; Belgium
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Yu Q, Wang Y, Yu Y, Li Y, Zhao S, Chen Y, Waqar AB, Fan J, Liu E. Expression of TRPV1 in rabbits and consuming hot pepper affects its body weight. Mol Biol Rep 2012; 39:7583-9. [PMID: 22327653 DOI: 10.1007/s11033-012-1592-1] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2011] [Accepted: 01/31/2012] [Indexed: 02/08/2023]
Abstract
The capsaicin receptor, known as transient receptor potential vanilloid subfamily member 1 (TRPV1), is an important membrane receptor that has been implicated in obesity, diabetes, metabolic syndrome and cardiovascular diseases. The rabbit model is considered excellent for studying cardiovascular and metabolic diseases, however, the tissue expression of TRPV1 and physiological functions of its ligand capsaicin on diet-induced obesity have not been fully defined in this model. In the current study, we investigated the tissue expression of TRPV1 in normal rabbits using real-time RT-PCR and Western blot analysis. Rabbit TRPV1 mRNA was highly expressed in a variety of organs, including the kidneys, adrenal gland, spleen and brain. A phylogenetic analysis showed that the amino acid sequence of rabbit TRPV1 was closer to human TRPV1 than rodent TRPV1. To examine the effect of capsaicin (a pungent compound in hot pepper) on body weight, rabbits were fed with either a high fat diet (as control) or high fat diet containing 1% hot pepper. We found that the body weight of the hot pepper-fed rabbits was significantly lower than the control group. We conclude that the intake of capsaicin can prevent diet-induced obesity and rabbit model is useful for the study of TRPV1 function in cardiovascular and metabolic diseases.
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Affiliation(s)
- Qi Yu
- Research Institute of Atherosclerotic Disease, Xi'an Jiaotong University School of Medicine, Xi'an 710061, China
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Donnerer J, Liebmann I. Thermal Stimulation of Primary Sensory Neurons in the Rat Hind Paw: Effect of Morphine on ERK1/2 Phosphorylation, TRPV1 and TRPA1 Channel Expression. Pharmacology 2012; 90:298-306. [DOI: 10.1159/000343133] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2012] [Accepted: 09/04/2012] [Indexed: 01/05/2023]
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Charrua A, Avelino A, Cruz F. Modulation of urinary bladder innervation: TRPV1 and botulinum toxin A. Handb Exp Pharmacol 2011:345-374. [PMID: 21290235 DOI: 10.1007/978-3-642-16499-6_17] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The persisting interest around neurotoxins such as vanilloids and botulinum toxin (BoNT) derives from their marked effect on detrusor overactivity refractory to conventional antimuscarinic treatments. In addition, both are administered by intravesical route. This offers three potential advantages. First, intravesical therapy is an easy way to provide high concentrations of pharmacological agents in the bladder tissue without causing unsuitable levels in other organs. Second, drugs effective on the bladder, but inappropriate for systemic administration, can be safely used as it is the case of vanilloids and BoNT. Third, the effects of one single treatment might be extremely longlasting, contributing to render these therapies highly attractive to patients despite the fact that the reasons to the prolonged effect are still incompletely understood. Attractive as it may be, intravesical pharmacological therapy should still be considered as a second-line treatment in patients refractory to conventional oral antimuscarinic therapy or who do not tolerate its systemic side effects. However, the increasing off-label use of these neurotoxins justifies a reappraisal of their pharmacological properties.
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Affiliation(s)
- Ana Charrua
- Institute of Histology and Embryology, Porto, Portugal
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Schumacher MA, Eilers H. TRPV1 splice variants: structure and function. Front Biosci (Landmark Ed) 2010; 15:872-82. [PMID: 20515731 DOI: 10.2741/3651] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The capsaicin receptor (TRPV1) is a non-selective cation channel predominantly expressed in specialized sensory neurons that detect painful stimuli. Although its many functional roles continue to be revealed, it has been confirmed to play a critical role in the perception of peripheral inflammatory hyperalgesia and pain. TRPV1 not only is sensitized and/or activated under a wide range of conditions including inflammation and nerve injury but also undergoes changes in expressed levels in response to these same pathologic conditions. Just as our understanding of the structural requirements of TRPV1 activation has grown, there is evidence that TRPV1 forms heteromeric channel complexes. This review is focused on the structural and functional consequence of TRPV1 splice variants: VR.5'sv, TRPV1b/beta and TRPV1var. Through their co-expression and formation of heteromeric complexes with TRPV1, they have been shown to modulate TRPV1 activation. Moreover, TRPV1 splice variant subunits may also contribute unique properties of activation such as the detection of hypertonic conditions.
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Affiliation(s)
- Mark A Schumacher
- Department of Anesthesia and Perioperative Care, University of California, San Francisco, CA 94143-0427, USA.
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Schumacher MA. Transient receptor potential channels in pain and inflammation: therapeutic opportunities. Pain Pract 2010; 10:185-200. [PMID: 20230457 DOI: 10.1111/j.1533-2500.2010.00358.x] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In ancient times, physicians had a limited number of therapies to provide pain relief. Not surprisingly, plant extracts applied topically often served as the primary analgesic plan. With the discovery of the capsaicin receptor (transient receptor potential cation channel, subfamily V, member 1 [TRPV1]), the search for "new" analgesics has returned to compounds used by physicians thousands of years ago. One such compound, capsaicin, couples the paradoxical action of nociceptor activation (burning pain) with subsequent analgesia following repeat or high-dose application. Investigating this "paradoxical" action of capsaicin has revealed several overlapping and complementary mechanisms to achieve analgesia including receptor desensitization, nociceptor dysfunction, neuropeptide depletion, and nerve terminal destruction. Moreover, the realization that TRPV1 is both sensitized and activated by endogenous products of inflammation, including bradykinin, H+, adenosine triphosphate, fatty acid derivatives, nerve growth factor, and trypsins, has renewed interest in TRPV1 as an important site of analgesia. Building on this foundation, a new series of preclinical and clinical studies targeting TRPV1 has been reported. These include trials using brief exposure to high-dose topical capsaicin in conjunction with prior application of a local anesthetic. Clinical use of resiniferatoxin, another ancient but potent TRPV1 agonist, is also being explored as a therapy for refractory pain. The development of orally administered high-affinity TRPV1 antagonists holds promise for pioneering a new generation of analgesics capable of blocking painful sensations at the site of inflammation and tissue injury. With the isolation of other members of the TRP channel family such as TRP cation channel, subfamily A, member 1, additional opportunities are emerging in the development of safe and effective analgesics.
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Affiliation(s)
- Mark A Schumacher
- Department of Anesthesia and Perioperative Care, University of California, San Francisco, California 94143-0427, USA.
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Jara-Oseguera A, Simon SA, Rosenbaum T. TRPV1: on the road to pain relief. Curr Mol Pharmacol 2010; 1:255-69. [PMID: 20021438 DOI: 10.2174/1874467210801030255] [Citation(s) in RCA: 130] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Historically, drug research targeted to pain treatment has focused on trying to prevent the propagation of action potentials in the periphery from reaching the brain rather than pinpointing the molecular basis underlying the initial detection of the nociceptive stimulus: the receptor itself. This has now changed, given that many receptors of nociceptive stimuli have been identified and/or cloned. Transient Receptor Potential (TRP) channels have been implicated in several physiological processes such as mechanical, chemical and thermal stimuli detection. Ten years after the cloning of TRPV1, compelling data has been gathered on the role of this channel in inflammatory and neuropathic states. TRPV1 activation in nociceptive neurons, where it is normally expressed, triggers the release of neuropeptides and transmitters resulting in the generation of action potentials that will be sent to higher CNS areas where they will often be perceived as pain. Its activation also will evoke the peripheral release of pro-inflammatory compounds that may sensitize other neurons to physical, thermal or chemical stimuli. For these reasons as well as because its continuous activation causes analgesia, TRPV1 has become a viable drug target for clinical use in the management of pain. This review will provide a general picture of the physiological and pathophysiological roles of the TRPV1 channel and of its structural, pharmacological and biophysical properties. Finally, it will provide the reader with an overall view of the status of the discovery of potential therapeutic agents for the management of chronic and neuropathic pain.
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Affiliation(s)
- Andrés Jara-Oseguera
- Departamento de Biofísica, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico
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