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Schumacher MA. Peripheral Neuroinflammation and Pain: How Acute Pain Becomes Chronic. Curr Neuropharmacol 2024; 22:6-14. [PMID: 37559537 DOI: 10.2174/1570159x21666230808111908] [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: 02/24/2023] [Revised: 04/05/2023] [Accepted: 04/26/2023] [Indexed: 08/11/2023] Open
Abstract
The number of individuals suffering from severe chronic pain and its social and financial impact is staggering. Without significant advances in our understanding of how acute pain becomes chronic, effective treatments will remain out of reach. This mini review will briefly summarize how critical signaling pathways initiated during the early phases of peripheral nervous system inflammation/ neuroinflammation establish long-term modifications of sensory neuronal function. Together with the recruitment of non-neuronal cellular elements, nociceptive transduction is transformed into a pathophysiologic state sustaining chronic peripheral sensitization and pain. Inflammatory mediators, such as nerve growth factor (NGF), can lower activation thresholds of sensory neurons through posttranslational modification of the pain-transducing ion channels transient-receptor potential TRPV1 and TRPA1. Performing a dual role, NGF also drives increased expression of TRPV1 in sensory neurons through the recruitment of transcription factor Sp4. More broadly, Sp4 appears to modulate a nociceptive transcriptome including TRPA1 and other genes encoding components of pain transduction. Together, these findings suggest a model where acute pain evoked by peripheral injury-induced inflammation becomes persistent through repeated cycles of TRP channel modification, Sp4-dependent overexpression of TRP channels and ongoing production of inflammatory mediators.
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Affiliation(s)
- Mark A Schumacher
- Department of Anesthesia and Perioperative Care and the UCSF Pain and Addiction Research Center, University of California, San Francisco, California, 94143 USA
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2
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Abstract
Transient receptor potential (TRP) ion channels are sophisticated signaling machines that detect a wide variety of environmental and physiological signals. Every cell in the body expresses one or more members of the extended TRP channel family, which consists of over 30 subtypes, each likely possessing distinct pharmacological, biophysical, and/or structural attributes. While the function of some TRP subtypes remains enigmatic, those involved in sensory signaling are perhaps best characterized and have served as models for understanding how these excitatory ion channels serve as polymodal signal integrators. With the recent resolution revolution in cryo-electron microscopy, these and other TRP channel subtypes are now yielding their secrets to detailed atomic analysis, which is beginning to reveal structural underpinnings of stimulus detection and gating, ion permeation, and allosteric mechanisms governing signal integration. These insights are providing a framework for designing and evaluating modality-specific pharmacological agents for treating sensory and other TRP channel-associated disorders. Expected final online publication date for the Annual Review of Biochemistry, Volume 91 is June 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Melinda M Diver
- Department of Physiology, University of California, San Francisco, California, USA; .,Current affiliation: Structural Biology Program, Memorial Sloan Kettering Cancer Center, New York, New York, USA
| | - John V Lin King
- Department of Physiology, University of California, San Francisco, California, USA; .,Current affiliation: Department of Biology, Stanford University, Palo Alto, California, USA
| | - David Julius
- Department of Physiology, University of California, San Francisco, California, USA;
| | - Yifan Cheng
- Department of Biochemistry and Biophysics, University of California, San Francisco, California, USA; .,Howard Hughes Medical Institute, University of California, San Francisco, California, USA
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3
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Go EJ, Ji J, Kim YH, Berta T, Park CK. Transient Receptor Potential Channels and Botulinum Neurotoxins in Chronic Pain. Front Mol Neurosci 2021; 14:772719. [PMID: 34776867 PMCID: PMC8586451 DOI: 10.3389/fnmol.2021.772719] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Accepted: 10/11/2021] [Indexed: 12/30/2022] Open
Abstract
Pain afflicts more than 1.5 billion people worldwide, with hundreds of millions suffering from unrelieved chronic pain. Despite widespread recognition of the importance of developing better interventions for the relief of chronic pain, little is known about the mechanisms underlying this condition. However, transient receptor potential (TRP) ion channels in nociceptors have been shown to be essential players in the generation and progression of pain and have attracted the attention of several pharmaceutical companies as therapeutic targets. Unfortunately, TRP channel inhibitors have failed in clinical trials, at least in part due to their thermoregulatory function. Botulinum neurotoxins (BoNTs) have emerged as novel and safe pain therapeutics because of their regulation of exocytosis and pro-nociceptive neurotransmitters. However, it is becoming evident that BoNTs also regulate the expression and function of TRP channels, which may explain their analgesic effects. Here, we summarize the roles of TRP channels in pain, with a particular focus on TRPV1 and TRPA1, their regulation by BoNTs, and briefly discuss the use of BoNTs for the treatment of chronic pain.
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Affiliation(s)
- Eun Jin Go
- Department of Physiology, Gachon Pain Center, Gachon University College of Medicine, Incheon, South Korea
| | - Jeongkyu Ji
- Gachon University College of Medicine, Incheon, South Korea
| | - Yong Ho Kim
- Department of Physiology, Gachon Pain Center, Gachon University College of Medicine, Incheon, South Korea
| | - Temugin Berta
- Department of Anesthesiology, Pain Research Center, University of Cincinnati Medical Center, Cincinnati, OH, United States
| | - Chul-Kyu Park
- Department of Physiology, Gachon Pain Center, Gachon University College of Medicine, Incheon, South Korea
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4
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Rhyu MR, Kim Y, Lyall V. Interactions between Chemesthesis and Taste: Role of TRPA1 and TRPV1. Int J Mol Sci 2021; 22:ijms22073360. [PMID: 33806052 PMCID: PMC8038011 DOI: 10.3390/ijms22073360] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 03/22/2021] [Accepted: 03/22/2021] [Indexed: 12/20/2022] Open
Abstract
In addition to the sense of taste and olfaction, chemesthesis, the sensation of irritation, pungency, cooling, warmth, or burning elicited by spices and herbs, plays a central role in food consumption. Many plant-derived molecules demonstrate their chemesthetic properties via the opening of transient receptor potential ankyrin 1 (TRPA1) and transient receptor potential vanilloid 1 (TRPV1) channels. TRPA1 and TRPV1 are structurally related thermosensitive cation channels and are often co-expressed in sensory nerve endings. TRPA1 and TRPV1 can also indirectly influence some, but not all, primary taste qualities via the release of substance P and calcitonin gene-related peptide (CGRP) from trigeminal neurons and their subsequent effects on CGRP receptor expressed in Type III taste receptor cells. Here, we will review the effect of some chemesthetic agonists of TRPA1 and TRPV1 and their influence on bitter, sour, and salt taste qualities.
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Affiliation(s)
- Mee-Ra Rhyu
- Korea Food Research Institute, Wanju-gun 55365, Korea;
- Correspondence: ; Tel.: +82-63-219-9268
| | - Yiseul Kim
- Korea Food Research Institute, Wanju-gun 55365, Korea;
| | - Vijay Lyall
- Department of Physiology and Biophysics, Virginia Commonwealth University, Richmond, VA 23298, USA;
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5
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Rapid effects of neurosteroids on neuronal plasticity and their physiological and pathological implications. Neurosci Lett 2021; 750:135771. [PMID: 33636284 DOI: 10.1016/j.neulet.2021.135771] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 02/15/2021] [Accepted: 02/20/2021] [Indexed: 11/22/2022]
Abstract
Current neuroscience research on neurosteroids and their synthetic analogues - neuroactive steroids - clearly demonstrate their drug likeness in a variety of neurological and psychiatric conditions. Moreover, research on neurosteroids continues to provide novel mechanistic insights into receptor activation or inhibition of various receptors. This mini-review will provide a high-level overview of the research area and discuss the various classes of potential physiological and pathological implications discovered so far.
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6
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Roh J, Go EJ, Park JW, Kim YH, Park CK. Resolvins: Potent Pain Inhibiting Lipid Mediators via Transient Receptor Potential Regulation. Front Cell Dev Biol 2020; 8:584206. [PMID: 33363143 PMCID: PMC7758237 DOI: 10.3389/fcell.2020.584206] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Accepted: 11/20/2020] [Indexed: 12/15/2022] Open
Abstract
Chronic pain is a serious condition that occurs in the peripheral nervous system (PNS) and the central nervous system (CNS). It is caused by inflammation or nerve damage that induces the release of inflammatory mediators from immune cells and/or protein kinase activation in neuronal cells. Both nervous systems are closely linked; therefore, inflammation or nerve damage in the PNS can affect the CNS (central sensitization). In this process, nociceptive transient receptor potential (TRP) channel activation and expression are increased. As a result, nociceptive neurons are activated, and pain signals to the brain are amplified and prolonged. In other words, suppressing the onset of pain signals in the PNS can suppress pain signals to the CNS. Resolvins, endogenous lipid mediators generated during the resolution phase of acute inflammation, inhibit nociceptive TRP ion channels and alleviate chronic pain. This paper summarizes the effect of resolvins in chronic pain control and discusses future scientific perspectives. Further study on the effect of resolvins on neuropathic pain will expand the scope of pain research.
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Affiliation(s)
- Jueun Roh
- Gachon Pain Center and Department of Physiology, College of Medicine, Gachon University, Incheon, South Korea
| | - Eun Jin Go
- Gachon Pain Center and Department of Physiology, College of Medicine, Gachon University, Incheon, South Korea
| | - Jin-Woo Park
- Department of Periodontology, School of Dentistry, Kyungpook National University, Daegu, South Korea
| | - Yong Ho Kim
- Gachon Pain Center and Department of Physiology, College of Medicine, Gachon University, Incheon, South Korea
| | - Chul-Kyu Park
- Gachon Pain Center and Department of Physiology, College of Medicine, Gachon University, Incheon, South Korea
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Behrendt M, Gruss F, Enzeroth R, Dembla S, Zhao S, Crassous PA, Mohr F, Nys M, Louros N, Gallardo R, Zorzini V, Wagner D, Economou A, Rousseau F, Schymkowitz J, Philipp SE, Rohacs T, Ulens C, Oberwinkler J. The structural basis for an on-off switch controlling Gβγ-mediated inhibition of TRPM3 channels. Proc Natl Acad Sci U S A 2020; 117:29090-29100. [PMID: 33122432 PMCID: PMC7682392 DOI: 10.1073/pnas.2001177117] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
TRPM3 channels play important roles in the detection of noxious heat and in inflammatory thermal hyperalgesia. The activity of these ion channels in somatosensory neurons is tightly regulated by µ-opioid receptors through the signaling of Gβγ proteins, thereby reducing TRPM3-mediated pain. We show here that Gβγ directly binds to a domain of 10 amino acids in TRPM3 and solve a cocrystal structure of this domain together with Gβγ. Using these data and mutational analysis of full-length proteins, we pinpoint three amino acids in TRPM3 and their interacting partners in Gβ1 that are individually necessary for TRPM3 inhibition by Gβγ. The 10-amino-acid Gβγ-interacting domain in TRPM3 is subject to alternative splicing. Its inclusion in or exclusion from TRPM3 channel proteins therefore provides a mechanism for switching on or off the inhibitory action that Gβγ proteins exert on TRPM3 channels.
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Affiliation(s)
- Marc Behrendt
- Institut für Physiologie und Pathophysiologie, Philipps-Universität Marburg, 35037 Marburg, Germany
- Center for Mind, Brain and Behavior (CMBB), Philipps-Universität Marburg and Justus-Liebig-Universität Giessen, 35032 Marburg, Germany
| | - Fabian Gruss
- Laboratory of Structural Neurobiology, Department of Cellular and Molecular Medicine, KU Leuven, 3000 Leuven, Belgium
| | - Raissa Enzeroth
- Institut für Physiologie und Pathophysiologie, Philipps-Universität Marburg, 35037 Marburg, Germany
- Center for Mind, Brain and Behavior (CMBB), Philipps-Universität Marburg and Justus-Liebig-Universität Giessen, 35032 Marburg, Germany
| | - Sandeep Dembla
- Institut für Physiologie und Pathophysiologie, Philipps-Universität Marburg, 35037 Marburg, Germany
- Center for Mind, Brain and Behavior (CMBB), Philipps-Universität Marburg and Justus-Liebig-Universität Giessen, 35032 Marburg, Germany
| | - Siyuan Zhao
- Department of Pharmacology, Physiology and Neuroscience, Rutgers New Jersey Medical School, Newark, NJ 07103
| | - Pierre-Antoine Crassous
- Department of Pharmacology, Physiology and Neuroscience, Rutgers New Jersey Medical School, Newark, NJ 07103
| | - Florian Mohr
- Institut für Physiologie und Pathophysiologie, Philipps-Universität Marburg, 35037 Marburg, Germany
| | - Mieke Nys
- Laboratory of Structural Neurobiology, Department of Cellular and Molecular Medicine, KU Leuven, 3000 Leuven, Belgium
| | - Nikolaos Louros
- Switch Laboratory, VIB Center for Brain and Disease Research, Department of Cellular and Molecular Medicine, KU Leuven, 3000 Leuven, Belgium
| | - Rodrigo Gallardo
- Switch Laboratory, VIB Center for Brain and Disease Research, Department of Cellular and Molecular Medicine, KU Leuven, 3000 Leuven, Belgium
| | - Valentina Zorzini
- Laboratory of Molecular Bacteriology, Department of Microbiology and Immunology, Rega Institute for Medical Research, KU Leuven, 3000 Leuven, Belgium
| | - Doris Wagner
- Institut für Physiologie und Pathophysiologie, Philipps-Universität Marburg, 35037 Marburg, Germany
| | - Anastassios Economou
- Laboratory of Molecular Bacteriology, Department of Microbiology and Immunology, Rega Institute for Medical Research, KU Leuven, 3000 Leuven, Belgium
| | - Frederic Rousseau
- Switch Laboratory, VIB Center for Brain and Disease Research, Department of Cellular and Molecular Medicine, KU Leuven, 3000 Leuven, Belgium
| | - Joost Schymkowitz
- Switch Laboratory, VIB Center for Brain and Disease Research, Department of Cellular and Molecular Medicine, KU Leuven, 3000 Leuven, Belgium
| | - Stephan E Philipp
- Experimentelle und Klinische Pharmakologie und Toxikologie, Universität des Saarlandes, 66421 Homburg, Germany
| | - Tibor Rohacs
- Department of Pharmacology, Physiology and Neuroscience, Rutgers New Jersey Medical School, Newark, NJ 07103
| | - Chris Ulens
- Laboratory of Structural Neurobiology, Department of Cellular and Molecular Medicine, KU Leuven, 3000 Leuven, Belgium;
| | - Johannes Oberwinkler
- Institut für Physiologie und Pathophysiologie, Philipps-Universität Marburg, 35037 Marburg, Germany;
- Center for Mind, Brain and Behavior (CMBB), Philipps-Universität Marburg and Justus-Liebig-Universität Giessen, 35032 Marburg, Germany
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8
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Achanta S, Jordt SE. Transient receptor potential channels in pulmonary chemical injuries and as countermeasure targets. Ann N Y Acad Sci 2020; 1480:73-103. [PMID: 32892378 PMCID: PMC7933981 DOI: 10.1111/nyas.14472] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Revised: 07/22/2020] [Accepted: 07/29/2020] [Indexed: 12/17/2022]
Abstract
The lung is highly sensitive to chemical injuries caused by exposure to threat agents in industrial or transportation accidents, occupational exposures, or deliberate use as weapons of mass destruction (WMD). There are no antidotes for the majority of the chemical threat agents and toxic inhalation hazards despite their use as WMDs for more than a century. Among several putative targets, evidence for transient receptor potential (TRP) ion channels as mediators of injury by various inhalational chemical threat agents is emerging. TRP channels are expressed in the respiratory system and are essential for homeostasis. Among TRP channels, the body of literature supporting essential roles for TRPA1, TRPV1, and TRPV4 in pulmonary chemical injuries is abundant. TRP channels mediate their function through sensory neuronal and nonneuronal pathways. TRP channels play a crucial role in complex pulmonary pathophysiologic events including, but not limited to, increased intracellular calcium levels, signal transduction, recruitment of proinflammatory cells, neurogenic inflammatory pathways, cough reflex, hampered mucus clearance, disruption of the integrity of the epithelia, pulmonary edema, and fibrosis. In this review, we summarize the role of TRP channels in chemical threat agents-induced pulmonary injuries and how these channels may serve as medical countermeasure targets for broader indications.
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Affiliation(s)
- Satyanarayana Achanta
- Department of Anesthesiology, Duke University School of Medicine, Durham, North Carolina
| | - Sven-Eric Jordt
- Department of Anesthesiology, Duke University School of Medicine, Durham, North Carolina
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, North Carolina
- Department of Psychiatry, Yale University School of Medicine, New Haven, Connecticut
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Abstract
Chemotherapy-induced peripheral neuropathy (CIPN) is a major challenge, with increasing impact as oncological treatments, using potentially neurotoxic chemotherapy, improve cancer cure and survival. Acute CIPN occurs during chemotherapy, sometimes requiring dose reduction or cessation, impacting on survival. Around 30% of patients will still have CIPN a year, or more, after finishing chemotherapy. Accurate assessment is essential to improve knowledge around prevalence and incidence of CIPN. Consensus is needed to standardize assessment and diagnosis, with use of well-validated tools, such as the EORTC-CIPN 20. Detailed phenotyping of the clinical syndrome moves toward a precision medicine approach, to individualize treatment. Understanding significant risk factors and pre-existing vulnerability may be used to improve strategies for CIPN prevention, or to use targeted treatment for established CIPN. No preventive therapies have shown significant clinical efficacy, although there are promising novel agents such as histone deacetylase 6 (HDAC6) inhibitors, currently in early phase clinical trials for cancer treatment. Drug repurposing, eg, metformin, may offer an alternative therapeutic avenue. Established treatment for painful CIPN is limited. Following recommendations for general neuropathic pain is logical, but evidence for agents such as gabapentinoids and amitriptyline is weak. The only agent currently recommended by the American Society of Clinical Oncology is duloxetine. Mechanisms are complex with changes in ion channels (sodium, potassium, and calcium), transient receptor potential channels, mitochondrial dysfunction, and immune cell interactions. Improved understanding is essential to advance CIPN management. On a positive note, there are many potential sites for modulation, with novel analgesic approaches.
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Affiliation(s)
- Lesley A Colvin
- Chair of Pain Medicine, Division of Population Health and Genomics, Ninewells Hospital and Medical School, University of Dundee, Dundee, Scotland
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Sheehan K, Lee J, Chong J, Zavala K, Sharma M, Philipsen S, Maruyama T, Xu Z, Guan Z, Eilers H, Kawamata T, Schumacher M. Transcription factor Sp4 is required for hyperalgesic state persistence. PLoS One 2019; 14:e0211349. [PMID: 30811405 PMCID: PMC6392229 DOI: 10.1371/journal.pone.0211349] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Accepted: 01/11/2019] [Indexed: 12/14/2022] Open
Abstract
Understanding how painful hypersensitive states develop and persist beyond the initial hours to days is critically important in the effort to devise strategies to prevent and/or reverse chronic painful states. Changes in nociceptor transcription can alter the abundance of nociceptive signaling elements, resulting in longer-term change in nociceptor phenotype. As a result, sensitized nociceptive signaling can be further amplified and nocifensive behaviors sustained for weeks to months. Building on our previous finding that transcription factor Sp4 positively regulates the expression of the pain transducing channel TRPV1 in Dorsal Root Ganglion (DRG) neurons, we sought to determine if Sp4 serves a broader role in the development and persistence of hypersensitive states in mice. We observed that more than 90% of Sp4 staining DRG neurons were small to medium sized, primarily unmyelinated (NF200 neg) and the majority co-expressed nociceptor markers TRPV1 and/or isolectin B4 (IB4). Genetically modified mice (Sp4+/-) with a 50% reduction of Sp4 showed a reduction in DRG TRPV1 mRNA and neuronal responses to the TRPV1 agonist-capsaicin. Importantly, Sp4+/- mice failed to develop persistent inflammatory thermal hyperalgesia, showing a reversal to control values after 6 hours. Despite a reversal of inflammatory thermal hyperalgesia, there was no difference in CFA-induced hindpaw swelling between CFA Sp4+/- and CFA wild type mice. Similarly, Sp4+/- mice failed to develop persistent mechanical hypersensitivity to hind-paw injection of NGF. Although Sp4+/- mice developed hypersensitivity to traumatic nerve injury, Sp4+/- mice failed to develop persistent cold or mechanical hypersensitivity to the platinum-based chemotherapeutic agent oxaliplatin, a non-traumatic model of neuropathic pain. Overall, Sp4+/- mice displayed a remarkable ability to reverse the development of multiple models of persistent inflammatory and neuropathic hypersensitivity. This suggests that Sp4 functions as a critical control point for a network of genes that conspire in the persistence of painful hypersensitive states.
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Affiliation(s)
- Kayla Sheehan
- Department of Anesthesia and Perioperative Care, University of California, San Francisco, San Francisco, California, United States of America
| | - Jessica Lee
- Department of Anesthesia and Perioperative Care, University of California, San Francisco, San Francisco, California, United States of America
| | - Jillian Chong
- Department of Anesthesia and Perioperative Care, University of California, San Francisco, San Francisco, California, United States of America
| | - Kathryn Zavala
- Department of Anesthesia and Perioperative Care, University of California, San Francisco, San Francisco, California, United States of America
| | - Manohar Sharma
- Department of Anesthesia and Perioperative Care, University of California, San Francisco, San Francisco, California, United States of America
| | - Sjaak Philipsen
- Department of Cell Biology, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Tomoyuki Maruyama
- Department of Anesthesiology, Wakayama Medical University, Wakayama, Japan
| | - Zheyun Xu
- Department of Anesthesia and Perioperative Care, University of California, San Francisco, San Francisco, California, United States of America
| | - Zhonghui Guan
- Department of Anesthesia and Perioperative Care, University of California, San Francisco, San Francisco, California, United States of America
| | - Helge Eilers
- Department of Anesthesia and Perioperative Care, University of California, San Francisco, San Francisco, California, United States of America
| | - Tomoyuki Kawamata
- Department of Anesthesiology, Wakayama Medical University, Wakayama, Japan
| | - Mark Schumacher
- Department of Anesthesia and Perioperative Care, University of California, San Francisco, San Francisco, California, United States of America
- * E-mail:
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Storozhuk MV, Zholos AV. TRP Channels as Novel Targets for Endogenous Ligands: Focus on Endocannabinoids and Nociceptive Signalling. Curr Neuropharmacol 2018; 16:137-150. [PMID: 28440188 PMCID: PMC5883376 DOI: 10.2174/1570159x15666170424120802] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2017] [Revised: 04/04/2017] [Accepted: 04/14/2017] [Indexed: 12/19/2022] Open
Abstract
Background: Chronic pain is a significant clinical problem and a very complex pathophysiological phenomenon. There is growing evidence that targeting the endocannabinoid system may be a useful approach to pain alleviation. Classically, the system includes G protein-coupled receptors of the CB1 and CB2 subtypes and their endogenous ligands. More recently, several subtypes of the large superfamily of cation TRP channels have been coined as “ionotropic cannabinoid receptors”, thus highlighting their role in cannabinoid signalling. Thus, the aim of this review was to explore the intimate connection between several “painful” TRP channels, endocannabinoids and nociceptive signalling. Methods: Research literature on this topic was critically reviewed allowing us not only summarize the existing evidence in this area of research, but also propose several possible cellular mechanisms linking nociceptive and cannabinoid signaling with TRP channels. Results: We begin with an overview of physiology of the endocannabinoid system and its major components, namely CB1 and CB2 G protein-coupled receptors, their two most studied endogenous ligands, anandamide and 2-AG, and several enzymes involved in endocannabinoid biosynthesis and degradation. The role of different endocannabinoids in the regulation of synaptic transmission is then discussed in detail. The connection between the endocannabinoid system and several TRP channels, especially TRPV1-4, TRPA1 and TRPM8, is then explored, while highlighting the role of these same channels in pain signalling. Conclusion: There is increasing evidence implicating several TRP subtypes not only as an integral part of the endocannabinoid system, but also as promising molecular targets for pain alleviation with the use of endo- and phytocannabinoids, especially when the function of these channels is upregulated under inflammatory conditions.
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Affiliation(s)
- Maksim V Storozhuk
- A.A. Bogomoletz Institute of Physiology, National Academy of Science of Ukraine, 4 Bogomoletz Street, Kiev 01024, Ukraine
| | - Alexander V Zholos
- A.A. Bogomoletz Institute of Physiology, National Academy of Science of Ukraine, 4 Bogomoletz Street, Kiev 01024, Ukraine.,Educational and Scientific Centre "Institute of Biology and Medicine", Taras Shevchenko Kiev National University, 2 Academician Glushkov Avenue, Kiev 03022, Ukraine
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12
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Gaub BM, Müller DJ. Mechanical Stimulation of Piezo1 Receptors Depends on Extracellular Matrix Proteins and Directionality of Force. NANO LETTERS 2017; 17:2064-2072. [PMID: 28164706 DOI: 10.1021/acs.nanolett.7b00177] [Citation(s) in RCA: 75] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Piezo receptors convert mechanical forces into electrical signals. In mammals, they play important roles in basic physiological functions including proprioception, sensation of touch, and vascular development. However, basic receptor properties like the gating mechanism, the interaction with extracellular matrix (ECM) proteins, and the response to mechanical stimulation, remain poorly understood. Here, we establish an atomic force microscopy (AFM)-based assay to mechanically stimulate Piezo1 receptors in living animal cells, while monitoring receptor activation in real-time using functional calcium imaging. Our experiments show that in the absence of ECM proteins Piezo1 receptors are relatively insensitive to mechanical forces pushing the cellular membrane, whereas they can hardly be activated by mechanically pulling the membrane. Yet, if conjugated with Matrigel, a mix of ECM proteins, the receptors become sensitized. Thereby, forces pulling the cellular membrane activate the receptor much more efficiently compared to pushing forces. Finally, we found that collagen IV, a component of the basal lamina, which forms a cohesive network and mechanical connection between cells, sensitizes Piezo1 receptors to mechanical pulling.
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Affiliation(s)
- Benjamin M Gaub
- Department of Biosystems Science and Engineering, ETH Zurich , 4058 Basel, Switzerland
| | - Daniel J Müller
- Department of Biosystems Science and Engineering, ETH Zurich , 4058 Basel, Switzerland
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13
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Abstract
Corneal transparency is dependent on the maintenance of the structural integrity and functional activity of its epithelial and endothelial limiting layers and the stroma. Different transient receptor potential (TRP) channel subtypes are expressed in cells and on corneal sensory nerve endings. They serve as sensors and transducers of environmental stimuli that can reduce tissue transparency. These nonselective cation channels are members of a superfamily sharing TRP box protein sequence homology having 6 membrane spanning domains with a pore between the fifth and sixth segments. TRP channels are composed of 4 monomeric subunits that oligomerize in homomeric or heteromeric configurations derived from different TRP subtypes belonging to the same or any of 6 different subfamilies. TRP subfamily members identified in the cornea include those belonging to the canonical, vanilloid, ankyrin, or melastatin subfamilies. In this review, we specifically focus on the functional roles of TRPV1 and TRPA1 expression in the cornea as their activation provides adaptive nociceptive and immune responses to noxious environmental stresses such as irritating ligands, temperature fluctuations, rises in ambient osmolarity, mechanical stretch, decline in pH, and tissue injury. Our previous studies have indicated that TRPV1 and TRPA1 subtypes are potential drug targets for improving corneal wound healing after alkali burns, because injury-induced fibrosis, neovascularization, and inflammation in either TRPV1 or TRPA1 gene-silenced mice were all significantly reduced.
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15
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Galer EL, Grace PM. Reactive aldehydes: a new player in inflammatory pain. ANNALS OF TRANSLATIONAL MEDICINE 2015; 3:S23. [PMID: 26046069 DOI: 10.3978/j.issn.2305-5839.2015.03.27] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Accepted: 02/03/2015] [Indexed: 11/14/2022]
Affiliation(s)
- Erika L Galer
- Department of Psychology and Neuroscience and the Center for Neuroscience, University of Colorado Boulder, Boulder, Co 80309, USA
| | - Peter M Grace
- Department of Psychology and Neuroscience and the Center for Neuroscience, University of Colorado Boulder, Boulder, Co 80309, USA
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