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Gründer S, Vanek J, Pissas KP. Acid-sensing ion channels and downstream signalling in cancer cells: is there a mechanistic link? Pflugers Arch 2024; 476:659-672. [PMID: 38175291 PMCID: PMC11006730 DOI: 10.1007/s00424-023-02902-z] [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: 11/23/2023] [Revised: 12/20/2023] [Accepted: 12/22/2023] [Indexed: 01/05/2024]
Abstract
It is increasingly appreciated that the acidic microenvironment of a tumour contributes to its evolution and clinical outcomes. However, our understanding of the mechanisms by which tumour cells detect acidosis and the signalling cascades that it induces is still limited. Acid-sensing ion channels (ASICs) are sensitive receptors for protons; therefore, they are also candidates for proton sensors in tumour cells. Although in non-transformed tissue, their expression is mainly restricted to neurons, an increasing number of studies have reported ectopic expression of ASICs not only in brain cancer but also in different carcinomas, such as breast and pancreatic cancer. However, because ASICs are best known as desensitizing ionotropic receptors that mediate rapid but transient signalling, how they trigger intracellular signalling cascades is not well understood. In this review, we introduce the acidic microenvironment of tumours and the functional properties of ASICs, point out some conceptual problems, summarize reported roles of ASICs in different cancers, and highlight open questions on the mechanisms of their action in cancer cells. Finally, we propose guidelines to keep ASIC research in cancer on solid ground.
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Affiliation(s)
- Stefan Gründer
- Institute of Physiology, RWTH Aachen University, Pauwelsstraße 30, 52074, Aachen, Germany.
| | - Jakob Vanek
- Institute of Physiology, RWTH Aachen University, Pauwelsstraße 30, 52074, Aachen, Germany
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2
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Hajjar S, Zhou X. pH sensing at the intersection of tissue homeostasis and inflammation. Trends Immunol 2023; 44:807-825. [PMID: 37714775 PMCID: PMC10543622 DOI: 10.1016/j.it.2023.08.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Revised: 08/13/2023] [Accepted: 08/13/2023] [Indexed: 09/17/2023]
Abstract
pH is tightly maintained at cellular, tissue, and systemic levels, and altered pH - particularly in the acidic range - is associated with infection, injury, solid tumors, and physiological and pathological inflammation. However, how pH is sensed and regulated and how it influences immune responses remain poorly understood at the tissue level. Applying conceptual frameworks of homeostatic and inflammatory circuitries, we categorize cellular and tissue components engaged in pH regulation, drawing parallels from established cases in physiology. By expressing various intracellular (pHi) and extracellular pH (pHe)-sensing receptors, the immune system may integrate information on tissue and cellular states into the regulation of homeostatic and inflammatory programs. We introduce the novel concept of resistance and adaptation responses to rationalize pH-dependent immunomodulation intertwined with homeostatic equilibrium and inflammatory control. We discuss emerging challenges and opportunities in understanding the immunological roles of pH sensing, which might reveal new strategies to combat inflammation and restore tissue homeostasis.
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Affiliation(s)
- Stephanie Hajjar
- Division of Gastroenterology, Hepatology and Nutrition, Boston Children's Hospital, Boston, MA 02115, USA; Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA; Broad Institute of MIT and Harvard, 300 Longwood Ave, Boston, MA 02115, USA
| | - Xu Zhou
- Division of Gastroenterology, Hepatology and Nutrition, Boston Children's Hospital, Boston, MA 02115, USA; Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA; Broad Institute of MIT and Harvard, 300 Longwood Ave, Boston, MA 02115, USA.
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3
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Fischer L, Schmidt A, Dopychai A, Joussen S, Joeres N, Oslender-Bujotzek A, Schmalzing G, Gründer S. Physiologically relevant acid-sensing ion channel (ASIC) 2a/3 heteromers have a 1:2 stoichiometry. Commun Biol 2023; 6:701. [PMID: 37422581 PMCID: PMC10329638 DOI: 10.1038/s42003-023-05087-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Accepted: 06/29/2023] [Indexed: 07/10/2023] Open
Abstract
Acid-sensing ion channels (ASICs) sense extracellular protons and are involved in synaptic transmission and pain sensation. ASIC1a and ASIC3 are the ASIC subunits with the highest proton sensitivity. ASIC2a in contrast has low proton sensitivity but increases the variability of ASICs by forming heteromers with ASIC1a or ASIC3. ASICs are trimers and for the ASIC1a/2a heteromer it has been shown that subunits randomly assemble with a flexible 1:2/2:1 stoichiometry. Both heteromers have almost identical proton sensitivity intermediate between ASIC1a and ASIC2a. Here, we investigated the stoichiometry of the ASIC2a/3 heteromer. Using electrophysiology, we extensively characterized, first, cells expressing ASIC2a and ASIC3 at different ratios, second, concatemeric channels with a fixed subunit stoichiometry, and, third, channels containing loss-of-functions mutations in specific subunits. Our results conclusively show that only ASIC2a/3 heteromers with a 1:2 stoichiometry had a proton-sensitivity intermediate between ASIC2a and ASIC3. In contrast, the proton sensitivity of ASIC2a/3 heteromers with a 2:1 stoichiometry was strongly acid-shifted by more than one pH unit, which suggests that they are not physiologically relevant. Together, our results reveal that the proton sensitivity of the two ASIC2a/3 heteromers is clearly different and that ASIC3 and ASIC1a make remarkably different contributions to heteromers with ASIC2a.
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Affiliation(s)
- Leon Fischer
- Institute of Physiology, RWTH Aachen University, Pauwelsstrasse 30, D-52074, Aachen, Germany
- Department of Anesthesiology, Technical University Dresden, Dresden, Germany
| | - Axel Schmidt
- Institute of Physiology, RWTH Aachen University, Pauwelsstrasse 30, D-52074, Aachen, Germany
- Institute of Human Genetics, University of Bonn, School of Medicine & University Hospital Bonn, Bonn, Germany
| | - Anke Dopychai
- Institute of Clinical Pharmacology, RWTH Aachen University, Wendlingweg, D-52074, Aachen, Germany
| | - Sylvia Joussen
- Institute of Physiology, RWTH Aachen University, Pauwelsstrasse 30, D-52074, Aachen, Germany
| | - Niko Joeres
- Institute of Physiology, RWTH Aachen University, Pauwelsstrasse 30, D-52074, Aachen, Germany
- Department of Nephrology and Clinical Immunology, RWTH Aachen University, Pauwelsstrasse 30, D-52074, Aachen, Germany
| | | | - Günther Schmalzing
- Institute of Clinical Pharmacology, RWTH Aachen University, Wendlingweg, D-52074, Aachen, Germany
| | - Stefan Gründer
- Institute of Physiology, RWTH Aachen University, Pauwelsstrasse 30, D-52074, Aachen, Germany.
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4
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Hawashin A, Brakmann IC, Tian Y, Gründer S, Ortega-Ramírez AM. Modulation of Acid-Sensing Ion Channels by Tannic Acid and Green Tea via a Membrane-Mediated Mechanism. ACS Chem Neurosci 2023. [PMID: 37379568 DOI: 10.1021/acschemneuro.3c00032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/30/2023] Open
Abstract
Acid-sensing ion channels (ASICs) are proton-gated ion channels that contribute to pain perception and neurotransmission. Being involved in sensing inflammation and ischemia, ASIC1a and ASIC3 are promising drug targets. Polyphenol tannic acid (TA) as well as green tea can interact with a variety of ion channels, but their effect on ASICs remains unknown. In addition, it is unknown whether they interact with ion channels via a common mechanism. Here, we show that TA is a potent modulator of ASICs. TA inhibited the transient current of rat ASIC3 expressed in HEK cells with an apparent IC50 of 2.2 ± 0.6 μM; it potentiated the sustained current and induced a slowly declining decay current. In addition, it produced an acidic shift of the pH-dependent activation of ASIC3 and inhibited the window current at pH 7.0. Moreover, TA inhibited the transient current of ASIC1a, ASIC1b, and ASIC2a. Pentagalloylglucose that is chemically identical to the central part of TA and a green tea extract both had effects on ASIC3 comparable to TA. TA and green tea inhibited inward currents generated by gramicidin channels, indicating interaction with the membrane. These results show that TA, pentagalloylglucose, and green tea modulate ASICs and identify alteration of the membrane as the potential common mechanism of this modulation. These properties will limit clinical application of these molecules.
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Affiliation(s)
- Ammar Hawashin
- Institute of Physiology, RWTH Aachen University, Pauwelsstraße 30, Aachen D-52074, Germany
| | - Ilka C Brakmann
- Institute of Physiology, RWTH Aachen University, Pauwelsstraße 30, Aachen D-52074, Germany
| | - Yuemin Tian
- Institute of Physiology, RWTH Aachen University, Pauwelsstraße 30, Aachen D-52074, Germany
| | - Stefan Gründer
- Institute of Physiology, RWTH Aachen University, Pauwelsstraße 30, Aachen D-52074, Germany
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5
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Research progress on the structure and biological diversities of 2-phenylindole derivatives in recent 20 years. Bioorg Chem 2023; 132:106342. [PMID: 36621157 DOI: 10.1016/j.bioorg.2023.106342] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Revised: 12/05/2022] [Accepted: 01/02/2023] [Indexed: 01/05/2023]
Abstract
The privileged structure binds to multiple receptors with high affinity, which is helpful to the development of new bioactive compounds. Indole is classified as a privileged structure, which may be one of the most important structural categories in drug discovery. As a special subset of indole compounds, 2-phenylindole seems to be one of most promising forerunners of drug development. In this paper, 106 articles were referenced to review the structural changes, biological activities and structure-activity relationship of compounds in recent 20 years, and classified them according to their pharmacological activities, from several aspects, including anticancer, antibacterial, anti-inflammatory, analgesic, antiviral, anti-parasite, the biological activities target to central nervous system, et al. It also points out the importance of artificial intelligence (AI) technology in discovery of new 2-phenylindole compounds in a broader prospect. This review will provide some ideas for researchers to develop new indole drugs.
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Osei-Owusu J, Ruan Z, Mihaljević L, Matasic DS, Chen KH, Lü W, Qiu Z. Molecular mechanism underlying desensitization of the proton-activated chloride channel PAC. eLife 2022; 11:82955. [PMID: 36547405 PMCID: PMC9779784 DOI: 10.7554/elife.82955] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Accepted: 12/12/2022] [Indexed: 12/24/2022] Open
Abstract
Desensitization is a common property of membrane receptors, including ion channels. The newly identified proton-activated chloride (PAC) channel plays an important role in regulating the pH and size of organelles in the endocytic pathway, and is also involved in acid-induced cell death. However, how the PAC channel desensitizes is largely unknown. Here, we show by patch-clamp electrophysiological studies that PAC (also known as TMEM206/ASOR) undergoes pH-dependent desensitization upon prolonged acid exposure. Through structure-guided and comprehensive mutagenesis, we identified several residues critical for PAC desensitization, including histidine (H) 98, glutamic acid (E) 94, and aspartic acid (D) 91 at the extracellular extension of the transmembrane helix 1 (TM1), as well as E107, D109, and E250 at the extracellular domain (ECD)-transmembrane domain (TMD) interface. Structural analysis and molecular dynamic simulations revealed extensive interactions between residues at the TM1 extension and those at the ECD-TMD interface. These interactions likely facilitate PAC desensitization by stabilizing the desensitized conformation of TM1, which undergoes a characteristic rotational movement from the resting and activated states to the desensitized state. Our studies establish a new paradigm of channel desensitization in this ubiquitously expressed ion channel and pave the way for future investigation of its relevance in cellular physiology and disease.
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Affiliation(s)
- James Osei-Owusu
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, United States
| | - Zheng Ruan
- Department of Structural Biology, Van Andel Institute, Grand Rapids, United States
| | - Ljubica Mihaljević
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, United States
| | - Daniel S Matasic
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, United States
| | - Kevin Hong Chen
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, United States
| | - Wei Lü
- Department of Structural Biology, Van Andel Institute, Grand Rapids, United States
| | - Zhaozhu Qiu
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, United States.,Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, United States
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7
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Verkest C, Salinas M, Diochot S, Deval E, Lingueglia E, Baron A. Mechanisms of Action of the Peptide Toxins Targeting Human and Rodent Acid-Sensing Ion Channels and Relevance to Their In Vivo Analgesic Effects. Toxins (Basel) 2022; 14:toxins14100709. [PMID: 36287977 PMCID: PMC9612379 DOI: 10.3390/toxins14100709] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Revised: 09/30/2022] [Accepted: 10/02/2022] [Indexed: 11/16/2022] Open
Abstract
Acid-sensing ion channels (ASICs) are voltage-independent H+-gated cation channels largely expressed in the nervous system of rodents and humans. At least six isoforms (ASIC1a, 1b, 2a, 2b, 3 and 4) associate into homotrimers or heterotrimers to form functional channels with highly pH-dependent gating properties. This review provides an update on the pharmacological profiles of animal peptide toxins targeting ASICs, including PcTx1 from tarantula and related spider toxins, APETx2 and APETx-like peptides from sea anemone, and mambalgin from snake, as well as the dimeric protein snake toxin MitTx that have all been instrumental to understanding the structure and the pH-dependent gating of rodent and human cloned ASICs and to study the physiological and pathological roles of native ASICs in vitro and in vivo. ASICs are expressed all along the pain pathways and the pharmacological data clearly support a role for these channels in pain. ASIC-targeting peptide toxins interfere with ASIC gating by complex and pH-dependent mechanisms sometimes leading to opposite effects. However, these dual pH-dependent effects of ASIC-inhibiting toxins (PcTx1, mambalgin and APETx2) are fully compatible with, and even support, their analgesic effects in vivo, both in the central and the peripheral nervous system, as well as potential effects in humans.
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Affiliation(s)
- Clément Verkest
- CNRS (Centre National de la Recherche Scientifique), IPMC (Institut de Pharmacologie Moléculaire et Cellulaire), LabEx ICST (Laboratory of Excellence in Ion Channel Science and Therapeutics), FHU InovPain (Fédération Hospitalo-Universitaire “Innovative Solutions in Refractory Chronic Pain”), Université Côte d’Azur, 660 Route des Lucioles, Sophia-Antipolis, 06560 Nice, France
- Department of Anesthesiology, University Medical Center Hamburg-Eppendorf, 20251 Hamburg, Germany
| | - Miguel Salinas
- CNRS (Centre National de la Recherche Scientifique), IPMC (Institut de Pharmacologie Moléculaire et Cellulaire), LabEx ICST (Laboratory of Excellence in Ion Channel Science and Therapeutics), FHU InovPain (Fédération Hospitalo-Universitaire “Innovative Solutions in Refractory Chronic Pain”), Université Côte d’Azur, 660 Route des Lucioles, Sophia-Antipolis, 06560 Nice, France
| | - Sylvie Diochot
- CNRS (Centre National de la Recherche Scientifique), IPMC (Institut de Pharmacologie Moléculaire et Cellulaire), LabEx ICST (Laboratory of Excellence in Ion Channel Science and Therapeutics), FHU InovPain (Fédération Hospitalo-Universitaire “Innovative Solutions in Refractory Chronic Pain”), Université Côte d’Azur, 660 Route des Lucioles, Sophia-Antipolis, 06560 Nice, France
| | - Emmanuel Deval
- CNRS (Centre National de la Recherche Scientifique), IPMC (Institut de Pharmacologie Moléculaire et Cellulaire), LabEx ICST (Laboratory of Excellence in Ion Channel Science and Therapeutics), FHU InovPain (Fédération Hospitalo-Universitaire “Innovative Solutions in Refractory Chronic Pain”), Université Côte d’Azur, 660 Route des Lucioles, Sophia-Antipolis, 06560 Nice, France
| | - Eric Lingueglia
- CNRS (Centre National de la Recherche Scientifique), IPMC (Institut de Pharmacologie Moléculaire et Cellulaire), LabEx ICST (Laboratory of Excellence in Ion Channel Science and Therapeutics), FHU InovPain (Fédération Hospitalo-Universitaire “Innovative Solutions in Refractory Chronic Pain”), Université Côte d’Azur, 660 Route des Lucioles, Sophia-Antipolis, 06560 Nice, France
| | - Anne Baron
- CNRS (Centre National de la Recherche Scientifique), IPMC (Institut de Pharmacologie Moléculaire et Cellulaire), LabEx ICST (Laboratory of Excellence in Ion Channel Science and Therapeutics), FHU InovPain (Fédération Hospitalo-Universitaire “Innovative Solutions in Refractory Chronic Pain”), Université Côte d’Azur, 660 Route des Lucioles, Sophia-Antipolis, 06560 Nice, France
- Correspondence:
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8
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Wang X, Kanda H, Tsujino T, Kogure Y, Zhu F, Yamamoto S, Sakaguchi T, Noguchi K, Dai Y. Reactive Oxygen Species Cause Exercise-Induced Angina in a Myocardial Ischaemia-Reperfusion Injury Model. Int J Mol Sci 2022; 23:ijms23052820. [PMID: 35269964 PMCID: PMC8910887 DOI: 10.3390/ijms23052820] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Revised: 02/28/2022] [Accepted: 03/02/2022] [Indexed: 11/26/2022] Open
Abstract
Percutaneous coronary intervention (PCI) effectively treats obstructive coronary artery syndrome. However, 30–40% patients continue to have angina after a successful PCI, thereby reducing patient satisfaction. The mechanisms underlying persistent angina after revascularisation therapy are still poorly understood; hence, the treatment or guideline for post-PCI angina remains unestablished. Thus, this study aimed to investigate the mechanisms underlying effort angina in animals following myocardial ischaemia-reperfusion (I/R) injury. Phosphorylated extracellular signal-regulated kinase (p-ERK), a marker for painful stimulation-induced neuronal activation, was used for the investigation. After a forced treadmill exercise (FTE), the number of p-ERK-expressing neurons increased in the superficial dorsal horn of the I/R model animals. Moreover, FTE evoked hydrogen peroxide (H2O2) production in the I/R-injured heart, inducing angina through TRPA1 activation on cardiac sensory fibres. Notably, the treatment of a TEMPOL, a reactive oxygen species scavenger, or TRPA1−/− mice successfully alleviated the FTE-induced p-ERK expression in the dorsal horn. The production of H2O2, a reactive oxygen species, through physical exercise contributes to angina development following I/R. Hence, our findings may be useful for understanding and treating angina following revascularisation therapy.
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Affiliation(s)
- Xiaohang Wang
- Department of Cardiovascular Surgery, Hyogo College of Medicine, Nishinomiya 663-8501, Hyogo, Japan; (X.W.); (T.S.)
- Department of Pharmacy, School of Pharmacy, Hyogo University of Health Sciences, Kobe 650-8530, Hyogo, Japan; (H.K.); (T.T.); (Y.K.); (F.Z.); (S.Y.)
| | - Hirosato Kanda
- Department of Pharmacy, School of Pharmacy, Hyogo University of Health Sciences, Kobe 650-8530, Hyogo, Japan; (H.K.); (T.T.); (Y.K.); (F.Z.); (S.Y.)
- Department of Anatomy and Neuroscience, Hyogo College of Medicine, Nishinomiya 663-8501, Hyogo, Japan;
| | - Takeshi Tsujino
- Department of Pharmacy, School of Pharmacy, Hyogo University of Health Sciences, Kobe 650-8530, Hyogo, Japan; (H.K.); (T.T.); (Y.K.); (F.Z.); (S.Y.)
- Department of Cardiovascular and Renal Medicine, Hyogo College of Medicine, Nishinomiya 663-8501, Hyogo, Japan
| | - Yoko Kogure
- Department of Pharmacy, School of Pharmacy, Hyogo University of Health Sciences, Kobe 650-8530, Hyogo, Japan; (H.K.); (T.T.); (Y.K.); (F.Z.); (S.Y.)
| | - Feng Zhu
- Department of Pharmacy, School of Pharmacy, Hyogo University of Health Sciences, Kobe 650-8530, Hyogo, Japan; (H.K.); (T.T.); (Y.K.); (F.Z.); (S.Y.)
| | - Satoshi Yamamoto
- Department of Pharmacy, School of Pharmacy, Hyogo University of Health Sciences, Kobe 650-8530, Hyogo, Japan; (H.K.); (T.T.); (Y.K.); (F.Z.); (S.Y.)
| | - Taichi Sakaguchi
- Department of Cardiovascular Surgery, Hyogo College of Medicine, Nishinomiya 663-8501, Hyogo, Japan; (X.W.); (T.S.)
| | - Koichi Noguchi
- Department of Anatomy and Neuroscience, Hyogo College of Medicine, Nishinomiya 663-8501, Hyogo, Japan;
| | - Yi Dai
- Department of Pharmacy, School of Pharmacy, Hyogo University of Health Sciences, Kobe 650-8530, Hyogo, Japan; (H.K.); (T.T.); (Y.K.); (F.Z.); (S.Y.)
- Department of Anatomy and Neuroscience, Hyogo College of Medicine, Nishinomiya 663-8501, Hyogo, Japan;
- Correspondence:
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Dulai JS, Smith ESJ, Rahman T. Acid-sensing ion channel 3: An analgesic target. Channels (Austin) 2021; 15:94-127. [PMID: 33258401 PMCID: PMC7801124 DOI: 10.1080/19336950.2020.1852831] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Accepted: 11/13/2020] [Indexed: 12/12/2022] Open
Abstract
Acid-sensing ion channel 3 (ASIC3) belongs to the epithelial sodium channel/degenerin (ENaC/DEG) superfamily. There are 7 different ASIC subunits encoded by 5 different genes. Most ASIC subunits form trimeric ion channels that upon activation by extracellular protons mediate a transient inward current inducing cellular excitability. ASIC subunits exhibit differential tissue expression and biophysical properties, and the ability of subunits to form homo- and heteromeric trimers further increases the complexity of currents measured and their pharmacological properties. ASIC3 is of particular interest, not only because it exhibits high expression in sensory neurones, but also because upon activation it does not fully inactivate: a transient current is followed by a sustained current that persists during a period of extracellular acidity, i.e. ASIC3 can encode prolonged acidosis as a nociceptive signal. Furthermore, certain mediators sensitize ASIC3 enabling smaller proton concentrations to activate it and other mediators can directly activate the channel at neutral pH. Moreover, there is a plethora of evidence using transgenic mouse models and pharmacology, which supports ASIC3 as being a potential target for development of analgesics. This review will focus on current understanding of ASIC3 function to provide an overview of how ASIC3 contributes to physiology and pathophysiology, examining the mechanisms by which it can be modulated, and highlighting gaps in current understanding and future research directions.
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Affiliation(s)
| | | | - Taufiq Rahman
- Department of Pharmacology, University of Cambridge, Cambridge, UK
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10
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Gornati D, Ciccone R, Vinciguerra A, Ippati S, Pannaccione A, Petrozziello T, Pizzi E, Hassan A, Colombo E, Barbini S, Milani M, Caccavone C, Randazzo P, Muzio L, Annunziato L, Menegon A, Secondo A, Mastrangelo E, Pignataro G, Seneci P. Synthesis and Characterization of Novel Mono- and Bis-Guanyl Hydrazones as Potent and Selective ASIC1 Inhibitors Able to Reduce Brain Ischemic Insult. J Med Chem 2021; 64:8333-8353. [PMID: 34097384 DOI: 10.1021/acs.jmedchem.1c00305] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Acid-sensitive ion channels (ASICs) are sodium channels partially permeable to Ca2+ ions, listed among putative targets in central nervous system (CNS) diseases in which a pH modification occurs. We targeted novel compounds able to modulate ASIC1 and to reduce the progression of ischemic brain injury. We rationally designed and synthesized several diminazene-inspired diaryl mono- and bis-guanyl hydrazones. A correlation between their predicted docking affinities for the acidic pocket (AcP site) in chicken ASIC1 and their inhibition of homo- and heteromeric hASIC1 channels in HEK-293 cells was found. Their activity on murine ASIC1a currents and their selectivity vs mASIC2a were assessed in engineered CHO-K1 cells, highlighting a limited isoform selectivity. Neuroprotective effects were confirmed in vitro, on primary rat cortical neurons exposed to oxygen-glucose deprivation followed by reoxygenation, and in vivo, in ischemic mice. Early lead 3b, showing a good selectivity for hASIC1 in human neurons, was neuroprotective against focal ischemia induced in mice.
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Affiliation(s)
- Davide Gornati
- Chemistry Department, University of Milan, Via Golgi 19, 20133 Milan, Italy
| | - Roselia Ciccone
- Division of Pharmacology, Department of Neuroscience, School of Medicine, University of Naples Federico II, Via Pansini 5, I-80131 Naples, Italy
| | - Antonio Vinciguerra
- Division of Pharmacology, Department of Neuroscience, School of Medicine, University of Naples Federico II, Via Pansini 5, I-80131 Naples, Italy
| | - Stefania Ippati
- Experimental Imaging Center, ALEMBIC-Advanced Light and Electron Microscopy BioImaging Center, San Raffaele Scientific Institute, Via Olgettina 60, I-20132 Milan, Italy
| | - Anna Pannaccione
- Division of Pharmacology, Department of Neuroscience, School of Medicine, University of Naples Federico II, Via Pansini 5, I-80131 Naples, Italy
| | - Tiziana Petrozziello
- Division of Pharmacology, Department of Neuroscience, School of Medicine, University of Naples Federico II, Via Pansini 5, I-80131 Naples, Italy
| | - Erika Pizzi
- Experimental Imaging Center, ALEMBIC-Advanced Light and Electron Microscopy BioImaging Center, San Raffaele Scientific Institute, Via Olgettina 60, I-20132 Milan, Italy
| | - Amal Hassan
- National Research Council-Biophysics Institute (CNR-IBF), and Biosciences Department University of Milan, Via Celoria, 26, I-20133 Milan, Italy
| | - Eleonora Colombo
- Chemistry Department, University of Milan, Via Golgi 19, 20133 Milan, Italy
| | - Stefano Barbini
- Chemistry Department, University of Milan, Via Golgi 19, 20133 Milan, Italy
| | - Mario Milani
- National Research Council-Biophysics Institute (CNR-IBF), and Biosciences Department University of Milan, Via Celoria, 26, I-20133 Milan, Italy
| | - Cecilia Caccavone
- Experimental Imaging Center, ALEMBIC-Advanced Light and Electron Microscopy BioImaging Center, San Raffaele Scientific Institute, Via Olgettina 60, I-20132 Milan, Italy
| | | | - Luca Muzio
- INSPE-Institute of Experimental Neurology, San Raffaele Scientific Institute, Via Olgettina 60, I-20132 Milan, Italy
| | | | - Andrea Menegon
- Experimental Imaging Center, ALEMBIC-Advanced Light and Electron Microscopy BioImaging Center, San Raffaele Scientific Institute, Via Olgettina 60, I-20132 Milan, Italy
| | - Agnese Secondo
- Division of Pharmacology, Department of Neuroscience, School of Medicine, University of Naples Federico II, Via Pansini 5, I-80131 Naples, Italy
| | - Eloise Mastrangelo
- National Research Council-Biophysics Institute (CNR-IBF), and Biosciences Department University of Milan, Via Celoria, 26, I-20133 Milan, Italy
| | - Giuseppe Pignataro
- Division of Pharmacology, Department of Neuroscience, School of Medicine, University of Naples Federico II, Via Pansini 5, I-80131 Naples, Italy
| | - Pierfausto Seneci
- Chemistry Department, University of Milan, Via Golgi 19, 20133 Milan, Italy
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11
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Vullo S, Ambrosio N, Kucera JP, Bignucolo O, Kellenberger S. Kinetic analysis of ASIC1a delineates conformational signaling from proton-sensing domains to the channel gate. eLife 2021; 10:66488. [PMID: 33729158 PMCID: PMC8009679 DOI: 10.7554/elife.66488] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Accepted: 03/16/2021] [Indexed: 11/13/2022] Open
Abstract
Acid-sensing ion channels (ASICs) are neuronal Na+ channels that are activated by a drop in pH. Their established physiological and pathological roles, involving fear behaviors, learning, pain sensation, and neurodegeneration after stroke, make them promising targets for future drugs. Currently, the ASIC activation mechanism is not understood. Here, we used voltage-clamp fluorometry (VCF) combined with fluorophore-quencher pairing to determine the kinetics and direction of movements. We show that conformational changes with the speed of channel activation occur close to the gate and in more distant extracellular sites, where they may be driven by local protonation events. Further, we provide evidence for fast conformational changes in a pathway linking protonation sites to the channel pore, in which an extracellular interdomain loop interacts via aromatic residue interactions with the upper end of a transmembrane helix and would thereby open the gate.
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Affiliation(s)
- Sabrina Vullo
- Department of Biomedical Sciences, University of Lausanne, Lausanne, Switzerland
| | - Nicolas Ambrosio
- Department of Biomedical Sciences, University of Lausanne, Lausanne, Switzerland
| | - Jan P Kucera
- Department of Physiology, University of Bern, Bern, Switzerland
| | - Olivier Bignucolo
- Department of Biomedical Sciences, University of Lausanne, Lausanne, Switzerland.,SIB, Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | - Stephan Kellenberger
- Department of Biomedical Sciences, University of Lausanne, Lausanne, Switzerland
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12
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Peng Z, Kellenberger S. Hydrogen Sulfide Upregulates Acid-sensing Ion Channels via the MAPK-Erk1/2 Signaling Pathway. FUNCTION (OXFORD, ENGLAND) 2021; 2:zqab007. [PMID: 35330812 PMCID: PMC8833866 DOI: 10.1093/function/zqab007] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Revised: 02/12/2021] [Accepted: 02/15/2021] [Indexed: 01/06/2023]
Abstract
Hydrogen sulfide (H2S) emerged recently as a new gasotransmitter and was shown to exert cellular effects by interacting with proteins, among them many ion channels. Acid-sensing ion channels (ASICs) are neuronal voltage-insensitive Na+ channels activated by extracellular protons. ASICs are involved in many physiological and pathological processes, such as fear conditioning, pain sensation, and seizures. We characterize here the regulation of ASICs by H2S. In transfected mammalian cells, the H2S donor NaHS increased the acid-induced ASIC1a peak currents in a time- and concentration-dependent manner. Similarly, NaHS potentiated also the acid-induced currents of ASIC1b, ASIC2a, and ASIC3. An upregulation induced by the H2S donors NaHS and GYY4137 was also observed with the endogenous ASIC currents of cultured hypothalamus neurons. In parallel with the effect on function, the total and plasma membrane expression of ASIC1a was increased by GYY4137, as determined in cultured cortical neurons. H2S also enhanced the phosphorylation of the extracellular signal-regulated kinase (pErk1/2), which belongs to the family of mitogen-activated protein kinases (MAPKs). Pharmacological blockade of the MAPK signaling pathway prevented the GYY4137-induced increase of ASIC function and expression, indicating that this pathway is required for ASIC regulation by H2S. Our study demonstrates that H2S regulates ASIC expression and function, and identifies the involved signaling mechanism. Since H2S shares several roles with ASICs, as for example facilitation of learning and memory, protection during seizure activity, and modulation of nociception, it may be possible that H2S exerts some of these effects via a regulation of ASIC function.
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Affiliation(s)
- Zhong Peng
- Department of Biomedical Sciences, University of Lausanne, Rue du Bugnon 27, 1011 Lausanne, Switzerland
| | - Stephan Kellenberger
- Department of Biomedical Sciences, University of Lausanne, Rue du Bugnon 27, 1011 Lausanne, Switzerland,Address correspondence to S.K. (e-mail: )
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13
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Bachmann M, Ortega-Ramírez A, Leisle L, Gründer S. Efficient expression of a cnidarian peptide-gated ion channel in mammalian cells. Channels (Austin) 2021; 15:273-283. [PMID: 33522420 PMCID: PMC7889164 DOI: 10.1080/19336950.2021.1882762] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
Abstract
Hydra Na+ channels (HyNaCs) are peptide-gated ion channels of the DEG/ENaC gene family that are directly activated by neuropeptides of the Hydra nervous system. They have previously been successfully characterized in Xenopus oocytes. To establish their expression in mammalian cells, we transiently expressed heteromeric HyNaC2/3/5 in human HEK 293 and monkey COS-7 cells. We found that the expression of HyNaC2/3/5 using native cDNAs was inefficient and that codon optimization strongly increased protein expression and current amplitude in patch-clamp experiments. We used the improved expression of codon-optimized channel subunits to perform Ca2+ imaging and to demonstrate their glycosylation pattern. In summary, we established efficient expression of a cnidarian ion channel in mammalian cell lines.
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Affiliation(s)
- Michèle Bachmann
- Department of Physiology, RWTH Aachen University , Aachen, Germany
| | | | - Lilia Leisle
- Department of Physiology, RWTH Aachen University , Aachen, Germany
| | - Stefan Gründer
- Department of Physiology, RWTH Aachen University , Aachen, Germany
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14
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Sapio MR, Vazquez FA, Loydpierson AJ, Maric D, Kim JJ, LaPaglia DM, Puhl HL, Lu VB, Ikeda SR, Mannes AJ, Iadarola MJ. Comparative Analysis of Dorsal Root, Nodose and Sympathetic Ganglia for the Development of New Analgesics. Front Neurosci 2021; 14:615362. [PMID: 33424545 PMCID: PMC7793666 DOI: 10.3389/fnins.2020.615362] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Accepted: 11/25/2020] [Indexed: 12/18/2022] Open
Abstract
Interoceptive and exteroceptive signals, and the corresponding coordinated control of internal organs and sensory functions, including pain, are received and orchestrated by multiple neurons within the peripheral, central and autonomic nervous systems. A central aim of the present report is to obtain a molecularly informed basis for analgesic drug development aimed at peripheral rather than central targets. We compare three key peripheral ganglia: nodose, sympathetic (superior cervical), and dorsal root ganglia in the rat, and focus on their molecular composition using next-gen RNA-Seq, as well as their neuroanatomy using immunocytochemistry and in situ hybridization. We obtained quantitative and anatomical assessments of transmitters, receptors, enzymes and signaling pathways mediating ganglion-specific functions. Distinct ganglionic patterns of expression were observed spanning ion channels, neurotransmitters, neuropeptides, G-protein coupled receptors (GPCRs), transporters, and biosynthetic enzymes. The relationship between ganglionic transcript levels and the corresponding protein was examined using immunohistochemistry for select, highly expressed, ganglion-specific genes. Transcriptomic analyses of spinal dorsal horn and intermediolateral cell column (IML), which form the termination of primary afferent neurons and the origin of preganglionic innervation to the SCG, respectively, disclosed pre- and post-ganglionic molecular-level circuits. These multimodal investigations provide insight into autonomic regulation, nodose transcripts related to pain and satiety, and DRG-spinal cord and IML-SCG communication. Multiple neurobiological and pharmacological contexts can be addressed, such as discriminating drug targets and predicting potential side effects, in analgesic drug development efforts directed at the peripheral nervous system.
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Affiliation(s)
- Matthew R Sapio
- Anesthesia Section, Department of Perioperative Medicine, National Institutes of Health Clinical Center, Bethesda, MD, United States
| | - Fernando A Vazquez
- Anesthesia Section, Department of Perioperative Medicine, National Institutes of Health Clinical Center, Bethesda, MD, United States
| | - Amelia J Loydpierson
- Anesthesia Section, Department of Perioperative Medicine, National Institutes of Health Clinical Center, Bethesda, MD, United States
| | - Dragan Maric
- Flow and Imaging Cytometry Core Facility, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, United States
| | - Jenny J Kim
- Anesthesia Section, Department of Perioperative Medicine, National Institutes of Health Clinical Center, Bethesda, MD, United States
| | - Danielle M LaPaglia
- Anesthesia Section, Department of Perioperative Medicine, National Institutes of Health Clinical Center, Bethesda, MD, United States
| | - Henry L Puhl
- Section on Neurotransmitter Signaling, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD, United States
| | - Van B Lu
- Section on Neurotransmitter Signaling, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD, United States
| | - Stephen R Ikeda
- Section on Neurotransmitter Signaling, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD, United States
| | - Andrew J Mannes
- Anesthesia Section, Department of Perioperative Medicine, National Institutes of Health Clinical Center, Bethesda, MD, United States
| | - Michael J Iadarola
- Anesthesia Section, Department of Perioperative Medicine, National Institutes of Health Clinical Center, Bethesda, MD, United States
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15
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Bhusal A, Rahman MH, Lee WH, Lee IK, Suk K. Satellite glia as a critical component of diabetic neuropathy: Role of lipocalin-2 and pyruvate dehydrogenase kinase-2 axis in the dorsal root ganglion. Glia 2020; 69:971-996. [PMID: 33251681 DOI: 10.1002/glia.23942] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 11/18/2020] [Accepted: 11/18/2020] [Indexed: 12/12/2022]
Abstract
Diabetic peripheral neuropathy (DPN) is a common complication of uncontrolled diabetes. The pathogenesis of DPN is associated with chronic inflammation in dorsal root ganglion (DRG), eventually causing structural and functional changes. Studies on DPN have primarily focused on neuronal component, and there is limited knowledge about the role of satellite glial cells (SGCs), although they completely enclose neuronal soma in DRG. Lipocalin-2 (LCN2) is a pro-inflammatory acute-phase protein found in high levels in diverse neuroinflammatory and metabolic disorders. In diabetic DRG, the expression of LCN2 was increased exclusively in the SGCs. This upregulation of LCN2 in SGCs correlated with increased inflammatory responses in DRG and sciatic nerve. Furthermore, diabetes-induced inflammation and morphological changes in DRG, as well as sciatic nerve, were attenuated in Lcn2 knockout (KO) mice. Lcn2 gene ablation also ameliorated neuropathy phenotype as determined by nerve conduction velocity and intraepidermal nerve fiber density. Mechanistically, studies using specific gene KO mice, adenovirus-mediated gene overexpression strategy, and primary cultures of DRG SGCs and neurons have demonstrated that LCN2 enhances the expression of mitochondrial gate-keeping regulator pyruvate dehydrogenase kinase-2 (PDK2) through PPARβ/δ, thereby inhibiting pyruvate dehydrogenase activity and increasing production of glycolytic end product lactic acid in DRG SGCs and neurons of diabetic mice. Collectively, our findings reveal a crucial role of glial LCN2-PPARβ/δ-PDK2-lactic acid axis in progression of DPN. Our results establish a link between pro-inflammatory LCN2 and glycolytic PDK2 in DRG SGCs and neurons and propose a novel glia-based mechanism and drug target for therapy of DPN. MAIN POINTS: Diabetes upregulates LCN2 in satellite glia, which in turn increases pyruvate dehydrogenase kinase-2 (PDK2) expression and lactic acid production in dorsal root ganglia (DRG). Glial LCN2-PDK2-lactic acid axis in DRG plays a crucial role in the pathogenesis of diabetic neuropathy.
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Affiliation(s)
- Anup Bhusal
- Department of Pharmacology, School of Medicine, Kyungpook National University, Daegu, Republic of Korea.,BK21 Plus KNU Biomedical Convergence Program, Department of Biomedical Sciences, School of Medicine, Kyungpook National University, Daegu, Republic of Korea
| | - Md Habibur Rahman
- Department of Pharmacology, School of Medicine, Kyungpook National University, Daegu, Republic of Korea.,BK21 Plus KNU Biomedical Convergence Program, Department of Biomedical Sciences, School of Medicine, Kyungpook National University, Daegu, Republic of Korea.,Brain Science and Engineering Institute, Kyungpook National University, Daegu, Republic of Korea
| | - Won-Ha Lee
- School of Life Sciences, Brain Korea 21 Plus/Kyungpook National University Creative BioResearch Group, Kyungpook National University, Daegu, Republic of Korea
| | - In-Kyu Lee
- Department of Internal Medicine, School of Medicine, Kyungpook National University, Kyungpook National University Hospital, Daegu, Republic of Korea.,Research Institute of Aging and Metabolism, Kyungpook National University, Daegu, Republic of Korea
| | - Kyoungho Suk
- Department of Pharmacology, School of Medicine, Kyungpook National University, Daegu, Republic of Korea.,BK21 Plus KNU Biomedical Convergence Program, Department of Biomedical Sciences, School of Medicine, Kyungpook National University, Daegu, Republic of Korea.,Brain Science and Engineering Institute, Kyungpook National University, Daegu, Republic of Korea
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16
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Szczepanska-Sadowska E, Cudnoch-Jedrzejewska A, Sadowski B. Differential role of specific cardiovascular neuropeptides in pain regulation: Relevance to cardiovascular diseases. Neuropeptides 2020; 81:102046. [PMID: 32284215 DOI: 10.1016/j.npep.2020.102046] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/17/2019] [Revised: 03/27/2020] [Accepted: 03/29/2020] [Indexed: 12/11/2022]
Abstract
In many instances, the perception of pain is disproportionate to the strength of the algesic stimulus. Excessive or inadequate pain sensation is frequently observed in cardiovascular diseases, especially in coronary ischemia. The mechanisms responsible for individual differences in the perception of cardiovascular pain are not well recognized. Cardiovascular disorders may provoke pain in multiple ways engaging molecules released locally in the heart due to tissue ischemia, inflammation or cellular stress, and through neurogenic and endocrine mechanisms brought into action by hemodynamic disturbances. Cardiovascular neuropeptides, namely angiotensin II (Ang II), angiotensin-(1-7) [Ang-(1-7)], vasopressin, oxytocin, and orexins belong to this group. Although participation of these peptides in the regulation of circulation and pain has been firmly established, their mutual interaction in the regulation of pain in cardiovascular diseases has not been profoundly analyzed. In the present review we discuss the regulation of the release, and mechanisms of the central and systemic actions of these peptides on the cardiovascular system in the context of their central and peripheral nociceptive (Ang II) and antinociceptive [Ang-(1-7), vasopressin, oxytocin, orexins] properties. We also consider the possibility that they may play a significant role in the modulation of pain in cardiovascular diseases. The rationale for focusing attention on these very compounds was based on the following premises (1) cardiovascular disturbances influence the release of these peptides (2) they regulate vascular tone and cardiac function and can influence the intensity of ischemia - the factor initiating pain signals in the cardiovascular system, (3) they differentially modulate nociception through peripheral and central mechanisms, and their effect strongly depends on specific receptors and site of action. Accordingly, an altered release of these peptides and/or pharmacological blockade of their receptors may have a significant but different impact on individual sensation of pain and comfort of an individual patient.
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Affiliation(s)
- Ewa Szczepanska-Sadowska
- Department of Experimental and Clinical Physiology, Laboratory of Centre for Preclinical Research, Medical University of Warsaw, Banacha 1b, Warsaw, Poland.
| | - Agnieszka Cudnoch-Jedrzejewska
- Department of Experimental and Clinical Physiology, Laboratory of Centre for Preclinical Research, Medical University of Warsaw, Banacha 1b, Warsaw, Poland
| | - Bogdan Sadowski
- School of Engineering and Health, Bitwy Warszawskiej 1920 r. 18, Warsaw, Poland
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17
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Papalampropoulou-Tsiridou M, Labrecque S, Godin AG, De Koninck Y, Wang F. Differential Expression of Acid - Sensing Ion Channels in Mouse Primary Afferents in Naïve and Injured Conditions. Front Cell Neurosci 2020; 14:103. [PMID: 32508593 PMCID: PMC7248332 DOI: 10.3389/fncel.2020.00103] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Accepted: 04/03/2020] [Indexed: 12/15/2022] Open
Abstract
Injury and inflammation cause tissue acidosis, which is a common feature of various painful conditions. Acid-Sensing Ion channels (ASICs) are amongst the main excitatory channels activated by extracellular protons and expressed in the nervous system. Six transcripts of ASIC subunits including ASIC1a, ASIC1b, ASIC2a, ASIC2b, ASIC3, and ASIC4 are encoded by four genes (Asic1–4) and have been identified in rodents. Most ASIC subunits are present at substantial levels in primary sensory neurons of dorsal root ganglia (DRG) except for ASIC4. However, their expression pattern in DRG neurons remains largely unclear, mainly due to the lack of antibodies with appropriate specificity. In this study, we examined in detail the expression pattern of ASIC1-3 subunits, including splice variants, in different populations of DRG neurons in adult mice using an in situ hybridization technique (RNAscope) with high sensitivity and specificity. We found that in naïve condition, all five subunits examined were expressed in the majority of myelinated, NF200-immunoreactive, DRG neurons (NF200+). However, ASIC subunits showed a very different expression pattern among non-myelinated DRG neuronal subpopulations: ASIC1 and ASIC3 were only expressed in CGRP-immunoreactive neurons (CGRP+), ASIC2a was mostly expressed in the majority of IB4-binding neurons (IB4+), while ASIC2b was expressed in almost all non-myelinated DRG neurons. We also found that at least half of sensory neurons expressed multiple types of ASIC subunits, indicating prevalence of heteromeric channels. In mice with peripheral nerve injury, the expression level of ASIC1a and ASIC1b in L4 DRG and ASIC3 in L5 DRG were altered in CGRP+ neurons, but not in IB4+ neurons. Furthermore, the pattern of change varied among DRGs depending on their segmental level, which pointed to differential regulatory mechanisms between afferent types and anatomical location. The distinct expression pattern of ASIC transcripts in naïve condition, and the differential regulation of ASIC subunits after peripheral nerve injury, suggest that ASIC subunits are involved in separate sensory modalities.
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Affiliation(s)
- Melina Papalampropoulou-Tsiridou
- CERVO Brain Research Centre, Québec Mental Health Institute, Québec, QC, Canada.,Graduate Program in Neuroscience, Université Laval, Québec, QC, Canada
| | - Simon Labrecque
- CERVO Brain Research Centre, Québec Mental Health Institute, Québec, QC, Canada
| | - Antoine G Godin
- CERVO Brain Research Centre, Québec Mental Health Institute, Québec, QC, Canada.,Graduate Program in Neuroscience, Université Laval, Québec, QC, Canada.,Department of Psychiatry and Neuroscience, Université Laval, Québec, QC, Canada
| | - Yves De Koninck
- CERVO Brain Research Centre, Québec Mental Health Institute, Québec, QC, Canada.,Graduate Program in Neuroscience, Université Laval, Québec, QC, Canada.,Department of Psychiatry and Neuroscience, Université Laval, Québec, QC, Canada
| | - Feng Wang
- CERVO Brain Research Centre, Québec Mental Health Institute, Québec, QC, Canada
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18
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Kim JS, Ducrocq GP, Kaufman MP. Functional knockout of ASIC3 attenuates the exercise pressor reflex in decerebrated rats with ligated femoral arteries. Am J Physiol Heart Circ Physiol 2020; 318:H1316-H1324. [PMID: 32302492 PMCID: PMC7346538 DOI: 10.1152/ajpheart.00137.2020] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 03/23/2020] [Accepted: 04/12/2020] [Indexed: 11/22/2022]
Abstract
The exercise pressor reflex arises from contracting muscle and is manifested by increases in arterial pressure, heart rate, and cardiac contractility. In patients with peripheral artery disease, the exercise pressor reflex is exaggerated. This effect is believed to be caused by a metabolite whose concentration is increased when the working muscles are inadequately perfused. Previous work in rats with simulated peripheral artery disease has shown that pharmacological blockade of acid-sensing ion channel 3 (ASIC3), which is found on group III and IV afferents, prevented the exaggeration of the exercise pressor reflex. Blockade of ASIC3, however, may have off-target effects that preclude a conclusion that ASIC3 plays a role in evoking the reflex in rats with simulated peripheral artery disease. In the present experiments performed in decerebrated rats with simulated peripheral artery disease, we compared the exercise pressor reflex in rats with a functional knockout of the ASIC3 (KO) with the reflex in their wild-type counterparts (WT). We found that the exercise pressor reflex in ASIC3 KO rats was significantly lower than the exercise pressor reflex in their WT counterparts (P < 0.05). ASIC 3 KO rats demonstrated lower pressor responses to intra-arterial injection of diprotonated phosphate (86 mM; pH 6.0), lactic acid (12 mM; pH 2.85), and capsaicin (0.2 μg; pH 7.2) (P < 0.05). In contrast, both ligated WT and ASIC3 KO rats displayed similar pressor responses to tendon stretch (P > 0.05). We conclude that ASIC3 play an important role in evoking the exaggerated exercise pressor reflex in rats with peripheral artery disease.NEW & NOTEWORTHY We used a genetic approach to test the hypothesis that the magnitude of the exercise pressor reflex evoked in ligated ASIC3 KO rats was significantly lower than the magnitude of the exercise pressor reflex evoked in their ligated wild-type (WT) counterparts. The pressor response to contraction in ligated ASIC3 KO rats was significantly smaller than was the pressor response to contraction in ligated WT rats.
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Affiliation(s)
- Joyce S Kim
- Heart and Vascular Institute and Department of Medicine, Penn State College of Medicine, Hershey, Pennsylvania
| | - Guillaume P Ducrocq
- Heart and Vascular Institute and Department of Medicine, Penn State College of Medicine, Hershey, Pennsylvania
| | - Marc P Kaufman
- Heart and Vascular Institute and Department of Medicine, Penn State College of Medicine, Hershey, Pennsylvania
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19
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Yang X, Luo Y, Liu Y, Gong C, Wang Y, Rao YJ, Peng GD, Gong Y. Mass production of thin-walled hollow optical fibers enables disposable optofluidic laser immunosensors. LAB ON A CHIP 2020; 20:923-930. [PMID: 32022063 DOI: 10.1039/c9lc01216h] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Disposable biosensors are of great importance in disease diagnosis due to their inherent merits of no cross-contamination and ease of use. Optofluidic laser (OFL) sensors are a new category of sensitive biosensors; however, it is challenging to cost-effectively mass-produce them to achieve disposability. Here, we report a disposable optofluidic laser immunosensor based on thin-walled hollow optical fibers (HOFs). Using a fiber draw tower, the fabrication parameters, including drawing speed and gas flow rate, are explored, and the HOF geometry is precisely controlled, which allows identical laser microring resonators to be distributed along the fibers. The disposable OFL immunosensor detects the protein concentration in the HOF through a wash-free immunoassay. Enabled by the disposable sensors, the statistical characteristics of 80 tests for each concentration greatly reduces the bioassay uncertainty. A low coefficient of variation (CV) of 3.3% confirms the high reproducibility of the disposable HOF-OFL sensors, and the mean of the normal distribution of the logarithmic OFL intensity serves as the sensing output. A limit of detection of 11 nM within a short assay time of 15 min is achieved. These disposable immunosensors possess the advantages of low cost, high reproducibility, fast assay, and low-volume consumption of sample and reagents. We believe that this work will inspire disposable optofluidics through the mass production of multifunctional microstructured optical fibers.
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Affiliation(s)
- Xi Yang
- Key Laboratory of Optical Fiber Sensing and Communications (Ministry of Education of China), University of Electronic Science and Technology of China, No. 2006, Xiyuan Ave., Chengdu, 611731, China.
| | - Yanhua Luo
- School of Electrical Engineering and Telecommunications, University of New South Wales, Sydney, NSW 2052, Australia.
| | - Yiling Liu
- Key Laboratory of Optical Fiber Sensing and Communications (Ministry of Education of China), University of Electronic Science and Technology of China, No. 2006, Xiyuan Ave., Chengdu, 611731, China.
| | - Chaoyang Gong
- Key Laboratory of Optical Fiber Sensing and Communications (Ministry of Education of China), University of Electronic Science and Technology of China, No. 2006, Xiyuan Ave., Chengdu, 611731, China. and School of Electrical and Electronics Engineering, Nanyang Technological University, 50 Nanyang Ave, Singapore, 639798, Singapore
| | - Yanqiong Wang
- Key Laboratory of Optical Fiber Sensing and Communications (Ministry of Education of China), University of Electronic Science and Technology of China, No. 2006, Xiyuan Ave., Chengdu, 611731, China.
| | - Yun-Jiang Rao
- Key Laboratory of Optical Fiber Sensing and Communications (Ministry of Education of China), University of Electronic Science and Technology of China, No. 2006, Xiyuan Ave., Chengdu, 611731, China.
| | - Gang-Ding Peng
- School of Electrical Engineering and Telecommunications, University of New South Wales, Sydney, NSW 2052, Australia.
| | - Yuan Gong
- Key Laboratory of Optical Fiber Sensing and Communications (Ministry of Education of China), University of Electronic Science and Technology of China, No. 2006, Xiyuan Ave., Chengdu, 611731, China.
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20
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Carattino MD, Montalbetti N. Acid-sensing ion channels in sensory signaling. Am J Physiol Renal Physiol 2020; 318:F531-F543. [PMID: 31984789 DOI: 10.1152/ajprenal.00546.2019] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Acid-sensing ion channels (ASICs) are cation-permeable channels that in the periphery are primarily expressed in sensory neurons that innervate tissues and organs. Soon after the cloning of the ASIC subunits, almost 20 yr ago, investigators began to use genetically modified mice to assess the role of these channels in physiological processes. These studies provide critical insights about the participation of ASICs in sensory processes, including mechanotransduction, chemoreception, and nociception. Here, we provide an extensive assessment of these findings and discuss the current gaps in knowledge with regard to the functions of ASICs in the peripheral nervous system.
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Affiliation(s)
- Marcelo D Carattino
- Renal-Electrolyte Division, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania.,Department of Cell Biology, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Nicolas Montalbetti
- Renal-Electrolyte Division, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
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21
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Endogenous Neuropeptide Nocistatin Is a Direct Agonist of Acid-Sensing Ion Channels (ASIC1, ASIC2 and ASIC3). Biomolecules 2019; 9:biom9090401. [PMID: 31443477 PMCID: PMC6769468 DOI: 10.3390/biom9090401] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 08/16/2019] [Accepted: 08/19/2019] [Indexed: 12/24/2022] Open
Abstract
Acid-sensing ion channel (ASIC) channels belong to the family of ligand-gated ion channels known as acid-sensing (proton-gated) ion channels. Only a few activators of ASICs are known. These are exogenous and endogenous molecules that cause a persistent, slowly desensitized current, different from an acid-induced current. Here we describe a novel endogenous agonist of ASICs-peptide nocistatin produced by neuronal cells and neutrophils as a part of prepronociceptin precursor protein. The rat nocistatin evoked currents in X. laevis oocytes expressing rat ASIC1a, ASIC1b, ASIC2a, and ASIC3 that were very similar in kinetic parameters to the proton-gated response. Detailed characterization of nocistatin action on rASIC1a revealed a proton-like dose-dependence of activation, which was accompanied by a dose-dependent decrease in the sensitivity of the channel to the protons. The toxin mambalgin-2, antagonist of ASIC1a, inhibited nocistatin-induced current, therefore the close similarity of mechanisms for ASIC1a activation by peptide and protons could be suggested. Thus, nocistatin is the first endogenous direct agonist of ASICs. This data could give a key to understanding ASICs activation regulation in the nervous system and also could be used to develop new drugs to treat pathological processes associated with ASICs activation, such as neurodegeneration, inflammation, and pain.
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22
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Uchitel OD, González Inchauspe C, Weissmann C. Synaptic signals mediated by protons and acid-sensing ion channels. Synapse 2019; 73:e22120. [PMID: 31180161 DOI: 10.1002/syn.22120] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Revised: 06/05/2019] [Accepted: 06/05/2019] [Indexed: 01/04/2023]
Abstract
Extracellular pH changes may constitute significant signals for neuronal communication. During synaptic transmission, changes in pH in the synaptic cleft take place. Its role in the regulation of presynaptic Ca2+ currents through multivesicular release in ribbon-type synapses is a proven phenomenon. In recent years, protons have been recognized as neurotransmitters that participate in neuronal communication in synapses of several regions of the CNS such as amygdala, nucleus accumbens, and brainstem. Protons are released by nerve stimulation and activate postsynaptic acid-sensing ion channels (ASICs). Several types of ASIC channels are expressed in the peripheral and central nervous system. The influx of Ca2+ through some subtypes of ASICs, as a result of synaptic transmission, agrees with the participation of ASICs in synaptic plasticity. Pharmacological and genetical inhibition of ASIC1a results in alterations in learning, memory, and phenomena like fear and cocaine-seeking behavior. The recognition of endogenous molecules, such as arachidonic acid, cytokines, histamine, spermine, lactate, and neuropeptides, capable of inhibiting or potentiating ASICs suggests the existence of mechanisms of synaptic modulation that have not yet been fully identified and that could be tuned by new emerging pharmacological compounds with potential therapeutic benefits.
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Affiliation(s)
- Osvaldo D Uchitel
- Departamento de Fisiología, Biología Molecular y Celular "Dr. Héctor Maldonado", Facultad de Ciencias Exactas y Naturales, Instituto de Fisiología, Biología molecular y Neurociencias (IFIBYNE) CONICET, Universidad de Buenos Aires, Ciudad Universitaria, (C1428EGA), Ciudad Autónoma de Buenos Aires, Argentina
| | - Carlota González Inchauspe
- Departamento de Fisiología, Biología Molecular y Celular "Dr. Héctor Maldonado", Facultad de Ciencias Exactas y Naturales, Instituto de Fisiología, Biología molecular y Neurociencias (IFIBYNE) CONICET, Universidad de Buenos Aires, Ciudad Universitaria, (C1428EGA), Ciudad Autónoma de Buenos Aires, Argentina
| | - Carina Weissmann
- Departamento de Fisiología, Biología Molecular y Celular "Dr. Héctor Maldonado", Facultad de Ciencias Exactas y Naturales, Instituto de Fisiología, Biología molecular y Neurociencias (IFIBYNE) CONICET, Universidad de Buenos Aires, Ciudad Universitaria, (C1428EGA), Ciudad Autónoma de Buenos Aires, Argentina
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Wu Y, Chen Z, Canessa CM. A valve-like mechanism controls desensitization of functional mammalian isoforms of acid-sensing ion channels. eLife 2019; 8:45851. [PMID: 31045491 PMCID: PMC6497441 DOI: 10.7554/elife.45851] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Accepted: 04/17/2019] [Indexed: 12/20/2022] Open
Abstract
ASICs are proton-gated sodium channels expressed in neurons. Structures of chicken ASIC1 in three conformations have advanced understanding of proton-mediated gating; however, a molecular mechanism describing desensitization from open and pre-open states (steady-state desensitization or SSD) remains elusive. A distinct feature of the desensitized state is an 180o rotation of residues L415 and N416 in the β11- β12 linker that was proposed to mediate desensitization; whether and how it translates into desensitization has not been explored yet. Using electrophysiological measurements of injected Xenopus oocytes, we show that Q276 in β9 strand works with L415 and N416 to mediate both types of desensitization in ASIC1a, ASIC2a and ASIC3. Q276 functions as a valve that enables or restricts rotation of L415 and N416 to keep the linker compressed, its relaxation lengthens openings and leads to sustained currents. At low proton concentrations, the proposed mechanism working in only one of three subunits of the channel is sufficient to induce SSD.
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Affiliation(s)
- Yangyu Wu
- Department of Basic Sciences, Tsinghua University School of Medicine, Beijing, China
| | - Zhuyuan Chen
- Department of Basic Sciences, Tsinghua University School of Medicine, Beijing, China
| | - Cecilia M Canessa
- Department of Basic Sciences, Tsinghua University School of Medicine, Beijing, China
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24
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Taktak F, Bütün V, Tuncer C, Demirel HH. Production of LMWH-conjugated core/shell hydrogels encapsulating paclitaxel for transdermal delivery: In vitro and in vivo assessment. Int J Biol Macromol 2019; 128:610-620. [PMID: 30708013 DOI: 10.1016/j.ijbiomac.2019.01.184] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Revised: 01/04/2019] [Accepted: 01/28/2019] [Indexed: 11/19/2022]
Abstract
Topical applications that reduce systemic toxic effects while increasing therapeutic efficacy are a promising alternative strategy. The aim of this study was to provide an enhanced transdermal delivery of low molecular weight heparin (LMWH) through the stratum corneum by using cationic carrier as a novel permeation enhancer. Recent studies have shown that heparin-conjugated biomaterials can be effective in inhibiting tumor growth during cancer treatment due to their high ability to bind growth factors. Paclitaxel (PCL) was co-encapsulated into the same cationic carrier for the purpose of improving of therapeutic efficacy for a combined cancer treatment with LMWH. In vitro and in vivo studies showed that the LMWH and PCL release was significantly affected by polymer molecular weight and block composition. Skin penetration tests have indicated that larger amounts of LMWH were absorbed from LMWH-gel conjugate through SC, than aqueous formula. However, it was found that the plasma transition of LMWH released from gel conjugate was lower compared to the plasma concentration of LMWH released from aqueous solution. It is recommended that PCL-loaded LMWH-conjugated core/shell hydrogels can be used as promising drug release systems for transdermal applications that can improve therapeutic efficacy and reduce side effects in a combined cancer treatment.
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Affiliation(s)
- Fulya Taktak
- Department of Chemical Engineering, Faculty of Engineering, Instutue of Natural and Applied Sciences, Department of Polymer Science and Technology, Uşak University, 64200 Uşak, Turkey.
| | - Vural Bütün
- Department of Chemistry, Faculty of Arts and Science, Eskisehir Osmangazi University, 26480 Eskisehir, Turkey
| | - Cansel Tuncer
- Department of Chemistry, Faculty of Arts and Science, Eskisehir Osmangazi University, 26480 Eskisehir, Turkey
| | - Hasan Hüseyin Demirel
- Bayat Vocational High School, Laboratory and Veterinary Health Program, Afyon Kocatepe University, 03200 Afyonkarahisar, Turkey
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25
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Shteinikov VY, Potapieva NN, Gmiro VE, Tikhonov DB. Hydrophobic Amines and Their Guanidine Analogues Modulate Activation and Desensitization of ASIC3. Int J Mol Sci 2019; 20:ijms20071713. [PMID: 30959896 PMCID: PMC6480424 DOI: 10.3390/ijms20071713] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 04/04/2019] [Accepted: 04/04/2019] [Indexed: 12/16/2022] Open
Abstract
Acid-sensing ion channel 3 (ASIC3) is an important member of the acid-sensing ion channels family, which is widely expressed in the peripheral nervous system and contributes to pain sensation. ASICs are targeted by various drugs and toxins. However, mechanisms and structural determinants of ligands' action on ASIC3 are not completely understood. In the present work we studied ASIC3 modulation by a series of "hydrophobic monoamines" and their guanidine analogs, which were previously characterized to affect other ASIC channels via multiple mechanisms. Electrophysiological analysis of action via whole-cell patch clamp method was performed using rat ASIC3 expressed in Chinese hamster ovary (CHO) cells. We found that the compounds studied inhibited ASIC3 activation by inducing acidic shift of proton sensitivity and slowed channel desensitization, which was accompanied by a decrease of the equilibrium desensitization level. The total effect of the drugs on the sustained ASIC3-mediated currents was the sum of these opposite effects. It is demonstrated that drugs' action on activation and desensitization differed in their structural requirements, kinetics of action, and concentration and state dependencies. Taken together, these findings suggest that effects on activation and desensitization are independent and are likely mediated by drugs binding to distinct sites in ASIC3.
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Affiliation(s)
- Vasilii Y Shteinikov
- I.M. Sechenov Institute of Evolutionary Physiology and Biochemistry RAS, St. Petersburg 194223, Russia.
| | - Natalia N Potapieva
- I.M. Sechenov Institute of Evolutionary Physiology and Biochemistry RAS, St. Petersburg 194223, Russia.
| | - Valery E Gmiro
- Institute of Experimental Medicine, RAMS, St. Petersburg 197376, Russia.
| | - Denis B Tikhonov
- I.M. Sechenov Institute of Evolutionary Physiology and Biochemistry RAS, St. Petersburg 194223, Russia.
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Abstract
A large series of different ion channels have been identified and investigated as potential targets for new medicines for the treatment of a variety of human diseases, including pain. Among these channels, the voltage gated calcium channels (VGCC) are inhibited by drugs for the treatment of migraine, neuropathic pain or intractable pain. Transient receptor potential (TRP) channels are emerging as important pain transducers as they sense low pH media or oxidative stress and other mediators and are abundantly found at sites of inflammation or tissue injury. Low pH may also activate acid sensing ion channels (ASIC) and mechanical forces stimulate the PIEZO channels. While potent agonists of TRP channels due to their desensitizing action on pain transmission are used as topical applications, the potential of TRP antagonists as pain therapeutics remains an exciting field of investigation. The study of ASIC or PIEZO channels in pain signaling is in an early stage, whereas antagonism of the purinergic P2X3 channels has been reported to provide beneficial effects in chronic intractable cough. The present chapter covers these intriguing channels in great detail, highlighting their diverse mechanisms and broad potential for therapeutic utility.
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Affiliation(s)
- Francesco De Logu
- Department of Health Sciences, Section of Clinical Pharmacology and Oncology, University of Florence, Florence, Italy
| | - Pierangelo Geppetti
- Department of Health Sciences, Section of Clinical Pharmacology and Oncology, University of Florence, Florence, Italy.
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27
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Chauhan AS, Sahoo GC, Dikhit MR, Das P. Acid-Sensing Ion Channels Structural Aspects, Pathophysiological Importance and Experimental Mutational Data Available Across Various Species to Target Human ASIC1. Curr Drug Targets 2018; 20:111-121. [DOI: 10.2174/1389450119666180820103316] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Revised: 08/01/2018] [Accepted: 08/15/2018] [Indexed: 01/16/2023]
Abstract
The H+-gated (proton) currents are widely present in brain sensory neuronal system and
various studies identified the structural units and deciphered the physiological and pathological function
of ion channels. The normal neuron requires an optimal pH to carry out its functions. In acidosis,
the ASICs (Acid-sensing Ion Channels) are activated in both the CNS (central nervous system) and
PNS (peripheral nervous system). ASICs are related to degenerin channels (DEGs), epithelial sodium
cation channels (ENaCs), and FMRF-amide (Phe-Met-Arg-Phe-NH2)-gated channels (FaNaC). Its activation
leads physiologically to pain perception, synaptic plasticity, learning and memory, fear,
ischemic neuronal injury, seizure termination, neuronal degeneration, and mechanosensation. It detects
the level of acid fluctuation in the extracellular environment and responds to acidic pH by increasing
the rate of membrane depolarization. It conducts cations like Na+ (Sodium) and Ca2+ (Calcium)
ions across the membrane upon protonation. The ASICs subtypes are characterized by differing
biophysical properties and pH sensitivities. The subtype ASIC1 is involved in various CNS diseases
and therefore focusing on its specific functional properties will guide in drug design methods. The review
highlights the cASIC1 (Chicken ASIC1) crystal structures, involvement in physiological environment
and limitations of currently available inhibitors. In addition, it details the mutational data
available to design an inhibitor against hASIC1 (Human ASIC1).
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Affiliation(s)
- Anurag Singh Chauhan
- Biomedical Informatics, Rajendra Memorial Research Institute of Medical Sciences (Indian Council of Medical Research), Agamkuan, Patna- 800 007, Bihar, India
| | - Ganesh Chandra Sahoo
- Biomedical Informatics, Rajendra Memorial Research Institute of Medical Sciences (Indian Council of Medical Research), Agamkuan, Patna- 800 007, Bihar, India
| | - Manas Ranjan Dikhit
- Biomedical Informatics, Rajendra Memorial Research Institute of Medical Sciences (Indian Council of Medical Research), Agamkuan, Patna- 800 007, Bihar, India
| | - Pradeep Das
- Department of Molecular Parasitology, Rajendra Memorial Research Institute of Medical Sciences (Indian Council of Medical Research), Agamkuan, Patna- 800 007, Bihar, India
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Yoder N, Gouaux E. Divalent cation and chloride ion sites of chicken acid sensing ion channel 1a elucidated by x-ray crystallography. PLoS One 2018; 13:e0202134. [PMID: 30157194 PMCID: PMC6114778 DOI: 10.1371/journal.pone.0202134] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Accepted: 07/27/2018] [Indexed: 12/21/2022] Open
Abstract
Acid sensing ion channels (ASICs) are proton-gated ion channels that are members of the degenerin/epithelial sodium channel superfamily and are expressed throughout central and peripheral nervous systems. ASICs have been implicated in multiple physiological processes and are subject to numerous forms of endogenous and exogenous regulation that include modulation by Ca2+ and Cl- ions. However, the mapping of ion binding sites as well as a structure-based understanding of the mechanisms underlying ionic modulation of ASICs have remained elusive. Here we present ion binding sites of chicken ASIC1a in resting and desensitized states at high and low pH, respectively, determined by anomalous diffraction x-ray crystallography. The acidic pocket serves as a nexus for divalent cation binding at both low and high pH, while we observe divalent cation binding within the central vestibule on the resting channel at high pH only. Moreover, neutralization of residues positioned to coordinate divalent cations via individual and combined Glu to Gln substitutions reduced, but did not extinguish, modulation of proton-dependent gating by Ca2+. Additionally, we demonstrate that anion binding at the canonical thumb domain site is state-dependent and present a previously undetected anion site at the mouth of the extracellular fenestrations on the resting channel. Our results map anion and cation sites on ASICs across multiple functional states, informing possible mechanisms of modulation and providing a blueprint for the design of therapeutics targeting ASICs.
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Affiliation(s)
- Nate Yoder
- Vollum Institute, Oregon Health & Science University, Portland, Oregon, United States of America
| | - Eric Gouaux
- Vollum Institute, Oregon Health & Science University, Portland, Oregon, United States of America
- Howard Hughes Medical Institute, Oregon Health & Science University, Portland, Oregon, United States of America
- * E-mail:
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29
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Reiners M, Margreiter MA, Oslender-Bujotzek A, Rossetti G, Gründer S, Schmidt A. The Conorfamide RPRFa Stabilizes the Open Conformation of Acid-Sensing Ion Channel 3 via the Nonproton Ligand-Sensing Domain. Mol Pharmacol 2018; 94:1114-1124. [PMID: 30012583 DOI: 10.1124/mol.118.112375] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Accepted: 07/06/2018] [Indexed: 01/26/2023] Open
Abstract
Acid-sensing ion channel 3 (ASIC3) is a proton-gated Na+ channel with important roles in pain. ASIC3 quickly desensitizes in less than a second, limiting its capacity to sense sustained acidosis during pain. RFamide neuropeptides are modulators of ASIC3 that slow its desensitization and induce a variable sustained current. The molecular mechanism of slowed desensitization and the RFamide binding site on ASIC3 are unknown. RPRFamide, a RFamide from the venom of a cone snail, has a comparatively high affinity for ASIC3 and strongly slows its desensitization. Here we show that covalent binding of a UV-sensitive RPRFamide variant to ASIC3 prevents desensitization, suggesting that RPRFamide has to unbind from ASIC3 before it can desensitize. Moreover, we show by in silico docking to a homology model of ASIC3 that a cavity in the lower palm domain, which is also known as the nonproton ligand-sensing domain, is a potential binding site of RPRFamide. Finally, using extensive mutagenesis of residues lining the nonproton ligand-sensing domain, we confirm that this domain is essential for RPRFamide modulation of ASIC3. As comparative analysis of ASIC crystal structures in the open and in the desensitized conformation suggests that the lower palm domain contracts during desensitization, our results collectively suggest that RPRFamide, and probably also other RFamide neuropeptides, bind to the nonproton ligand-sensing domain to stabilize the open conformation of ASIC3.
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Affiliation(s)
- Melissa Reiners
- Institute of Physiology (M.R., A.O.-B., S.G., A.S.) and Department of Oncology, Hematology and Stem Cell Transplantation (G.R.), RWTH Aachen University, Aachen, Germany; and Computational Biomedicine - Institute for Advanced Simulation (IAS)/Institute of Neuroscience and Medicine (INM) and Jülich Supercomputing Centre (JSC), Forschungszentrum Jülich, Jülich, Germany (M.A.M., G.R.)
| | - Michael A Margreiter
- Institute of Physiology (M.R., A.O.-B., S.G., A.S.) and Department of Oncology, Hematology and Stem Cell Transplantation (G.R.), RWTH Aachen University, Aachen, Germany; and Computational Biomedicine - Institute for Advanced Simulation (IAS)/Institute of Neuroscience and Medicine (INM) and Jülich Supercomputing Centre (JSC), Forschungszentrum Jülich, Jülich, Germany (M.A.M., G.R.)
| | - Adrienne Oslender-Bujotzek
- Institute of Physiology (M.R., A.O.-B., S.G., A.S.) and Department of Oncology, Hematology and Stem Cell Transplantation (G.R.), RWTH Aachen University, Aachen, Germany; and Computational Biomedicine - Institute for Advanced Simulation (IAS)/Institute of Neuroscience and Medicine (INM) and Jülich Supercomputing Centre (JSC), Forschungszentrum Jülich, Jülich, Germany (M.A.M., G.R.)
| | - Giulia Rossetti
- Institute of Physiology (M.R., A.O.-B., S.G., A.S.) and Department of Oncology, Hematology and Stem Cell Transplantation (G.R.), RWTH Aachen University, Aachen, Germany; and Computational Biomedicine - Institute for Advanced Simulation (IAS)/Institute of Neuroscience and Medicine (INM) and Jülich Supercomputing Centre (JSC), Forschungszentrum Jülich, Jülich, Germany (M.A.M., G.R.)
| | - Stefan Gründer
- Institute of Physiology (M.R., A.O.-B., S.G., A.S.) and Department of Oncology, Hematology and Stem Cell Transplantation (G.R.), RWTH Aachen University, Aachen, Germany; and Computational Biomedicine - Institute for Advanced Simulation (IAS)/Institute of Neuroscience and Medicine (INM) and Jülich Supercomputing Centre (JSC), Forschungszentrum Jülich, Jülich, Germany (M.A.M., G.R.)
| | - Axel Schmidt
- Institute of Physiology (M.R., A.O.-B., S.G., A.S.) and Department of Oncology, Hematology and Stem Cell Transplantation (G.R.), RWTH Aachen University, Aachen, Germany; and Computational Biomedicine - Institute for Advanced Simulation (IAS)/Institute of Neuroscience and Medicine (INM) and Jülich Supercomputing Centre (JSC), Forschungszentrum Jülich, Jülich, Germany (M.A.M., G.R.)
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30
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Yan XG, Li WG, Qi X, Zhu JJ, Huang C, Han SL, Jiang Q, Xu TL, Liu JH. Subtype-selective inhibition of acid-sensing ion channel 3 by a natural flavonoid. CNS Neurosci Ther 2018; 25:47-56. [PMID: 29781252 DOI: 10.1111/cns.12979] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Revised: 04/23/2018] [Accepted: 04/25/2018] [Indexed: 01/10/2023] Open
Abstract
AIMS Acid-sensing ion channels (ASICs) are extracellular proton-gated cation channels that have been implicated in multiple physiological and pathological processes, and peripheral ASIC3 prominently participate into the pathogenesis of chronic pain, itch, and neuroinflammation, which necessitates the need for discovery and development of novel modulators in a subtype-specific manner. METHODS Whole-cell patch clamp recordings and behavioral assays were used to examine the effect of several natural compounds on the ASIC-mediated currents and acid-induced nocifensive behavior, respectively. RESULTS We identified a natural flavonoid compound, (-)-epigallocatechin gallate (EGCG, compound 11), that acts as a potent inhibitor for the ASIC3 channel in an isoform-specific way. The compound 11 inhibited ASIC3 currents with an apparent half maximal inhibitory concentration of 13.2 μmol/L when measured at pH 5.0. However, at the concentration up to 100 μmol/L, the compound 11 had no significant impacts on the homomeric ASIC1a, 1b, and 2a channels. In contrast to most of the known ASIC inhibitors that usually bear either basic or carboxylic groups, the compound 11 belongs to the polyphenolic family. In compound 11, both the chirality and the 3-hydroxyl group of its pyrogallol part, in addition to the integrity of the gallate part, are crucial for the inhibitory efficacy. Finally, EGCG was found significantly to decrease the acid-induced nocifensive behavior in mice. CONCLUSION Taken together, these results thus defined a novel backbone structure for small molecule drug design targeting ASIC3 channels to treat pain-related diseases.
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Affiliation(s)
- Xiao-Gang Yan
- Departments of Chemistry, Anatomy and Physiology, College of Basic Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Wei-Guang Li
- Departments of Chemistry, Anatomy and Physiology, College of Basic Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xin Qi
- Departments of Chemistry, Anatomy and Physiology, College of Basic Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jia-Jie Zhu
- Departments of Chemistry, Anatomy and Physiology, College of Basic Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Chen Huang
- Departments of Chemistry, Anatomy and Physiology, College of Basic Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Shao-Ling Han
- Departments of Chemistry, Anatomy and Physiology, College of Basic Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Qin Jiang
- Departments of Chemistry, Anatomy and Physiology, College of Basic Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Tian-Le Xu
- Departments of Chemistry, Anatomy and Physiology, College of Basic Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jian-Hua Liu
- Departments of Chemistry, Anatomy and Physiology, College of Basic Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai, China
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Lehmke L, Coburn M, Möller M, Blaumeiser-Debarry R, Lenzig P, Wiemuth D, Gründer S. Inhalational anesthetics accelerate desensitization of acid-sensing ion channels. Neuropharmacology 2018; 135:496-505. [PMID: 29627444 DOI: 10.1016/j.neuropharm.2018.04.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Revised: 03/27/2018] [Accepted: 04/04/2018] [Indexed: 10/17/2022]
Abstract
Acid-sensing ion channels (ASICs) are neuronal Na+ channels that are activated by extracellular acidification. Inhibiting ASICs is neuroprotective in mouse models of ischemic stroke. As inhalational anesthetics interact with many ion channels and as some of them have neuroprotective effects, we hypothesized that inhalational anesthetics modulate ASICs. We expressed different homo- and heteromeric ASICs heterologously in Xenopus oocytes. We co-applied with acidic pH the halogenated inhalational anesthetics sevoflurane, desflurane, and isoflurane and the noble gases xenon and argon at concentrations that are roughly equivalent to their minimal alveolar concentrations and analyzed their effect on current kinetics and amplitude. Sevoflurane, desflurane, and isoflurane as well as xenon and argon accelerated by a factor of ∼1.5 channel desensitization of the main ASICs of the central nervous system: homomeric ASIC1a and heteromeric ASIC1a/2a and ASIC1a/2b. Moreover, they decreased current amplitudes by ∼25%. For example, isoflurane accelerated desensitization of homomeric ASIC1a from 1.0 ± 0.4 s (mean ± SD) to 0.6 ± 0.2 s (n = 12; p = 0.0003) and decreased current amplitudes from 12.1 ± 7.5 μA to 9.3 ± 5.6 μA (n = 12; p = 0.0009). While inhalational anesthetics had similar effects on homomeric ASIC3, desensitization of ASIC1b was only accelerated by halogenated anesthetics but not noble gases; desensitization of homomeric ASIC2a was not modulated. In summary, we found a significant modulation of ASICs by different inhalational anesthetics. We conclude that ASICs should be considered as relevant targets of inhalation anesthetics.
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Affiliation(s)
- Linda Lehmke
- Institute of Physiology, RWTH Aachen University, Aachen, Germany
| | - Mark Coburn
- Department of Anesthesiology, RWTH Aachen University, Aachen, Germany
| | - Manfred Möller
- Institute for Occupational, Social and Environmental Medicine, RWTH Aachen University, Aachen, Germany
| | | | - Pia Lenzig
- Institute of Physiology, RWTH Aachen University, Aachen, Germany
| | - Dominik Wiemuth
- Institute of Physiology, RWTH Aachen University, Aachen, Germany
| | - Stefan Gründer
- Institute of Physiology, RWTH Aachen University, Aachen, Germany.
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32
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Abstract
Acid-sensing ion channels (ASICs) are a family of ion channels, consisting of four members; ASIC1 to 4. These channels are sensitive to changes in pH and are expressed throughout the central and peripheral nervous systems-including brain, spinal cord, and sensory ganglia. They have been implicated in a number of neurological conditions such as stroke and cerebral ischemia, traumatic brain injury, and epilepsy, and more recently in migraine. Their expression within areas of interest in the brain in migraine, such as the hypothalamus and PAG, their demonstrated involvement in preclinical models of meningeal afferent signaling, and their role in cortical spreading depression (the electrophysiological correlate of migraine aura), has enhanced research interest into these channels as potential therapeutic targets in migraine. Migraine is a disorder with a paucity of both acute and preventive therapies available, in which at best 50% of patients respond to available medications, and these medications often have intolerable side effects. There is therefore a great need for therapeutic development for this disabling condition. This review will summarize the understanding of the structure and CNS expression of ASICs, the mechanisms for their potential role in nociception, recent work in migraine, and areas for future research and drug development.
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Affiliation(s)
- Nazia Karsan
- Headache Group, Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, Kings College London, Denmark Hill, London, SE5 9PJ, UK
| | - Eric B Gonzales
- TCU and UNTHSC School of Medicine (applicant for LCME accreditation), Department of Medical Education, 3500 Camp Bowie Blvd., Fort Worth, TX, 76107, USA
| | - Gregory Dussor
- School of Behavioral and Brain Sciences, The University of Texas at Dallas, 800 West Campbell Road, BSB-14, Richardson, TX, 75080, USA.
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33
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Yoder N, Yoshioka C, Gouaux E. Gating mechanisms of acid-sensing ion channels. Nature 2018; 555:397-401. [PMID: 29513651 PMCID: PMC5966032 DOI: 10.1038/nature25782] [Citation(s) in RCA: 131] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2017] [Accepted: 01/15/2018] [Indexed: 12/12/2022]
Abstract
Acid-sensing ion channels (ASICs) are trimeric, proton-gated and sodium-selective members of the epithelial sodium channel/degenerin (ENaC/DEG) superfamily of ion channels and are expressed throughout vertebrate central and peripheral nervous systems. Gating of ASICs occurs on a millisecond time scale and the mechanism involves three conformational states: high pH resting, low pH open and low pH desensitized. Existing X-ray structures of ASIC1a describe the conformations of the open and desensitized states, but the structure of the high pH resting state and detailed mechanisms of the activation and desensitization of the channel have remained elusive. Here we present structures of the high pH resting state of homotrimeric chicken (Gallus gallus) ASIC1a, determined by X-ray crystallography and single particle cryo-electron microscopy, and present a comprehensive molecular mechanism for proton-dependent gating in ASICs. In the resting state, the position of the thumb domain is further from the three-fold molecular axis, thereby expanding the 'acidic pocket' in comparison to the open and desensitized states. Activation therefore involves 'closure' of the thumb into the acidic pocket, expansion of the lower palm domain and an iris-like opening of the channel gate. Furthermore, we demonstrate how the β11-β12 linkers that demarcate the upper and lower palm domains serve as a molecular 'clutch', and undergo a simple rearrangement to permit rapid desensitization.
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Affiliation(s)
- Nate Yoder
- Vollum Institute, Oregon Health and Science University, Portland, Oregon 97239, USA
| | - Craig Yoshioka
- Department of Biomedical Engineering, Oregon Health and Science University, 2730 SW Moody Ave, Portland, Oregon 97201, USA
| | - Eric Gouaux
- Vollum Institute, Oregon Health and Science University, Portland, Oregon 97239, USA.,Howard Hughes Medical Institute, Oregon Health and Science University, Portland, Oregon 97239, USA
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Ievglevskyi O, Isaev D, Netsyk O, Romanov A, Fedoriuk M, Maximyuk O, Isaeva E, Akaike N, Krishtal O. Acid-sensing ion channels regulate spontaneous inhibitory activity in the hippocampus: possible implications for epilepsy. Philos Trans R Soc Lond B Biol Sci 2017; 371:rstb.2015.0431. [PMID: 27377725 DOI: 10.1098/rstb.2015.0431] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/18/2016] [Indexed: 12/12/2022] Open
Abstract
Acid-sensing ion channels (ASICs) play an important role in numerous functions in the central and peripheral nervous systems ranging from memory and emotions to pain. The data correspond to a recent notion that each neuron and many glial cells of the mammalian brain express at least one member of the ASIC family. However, the mechanisms underlying the involvement of ASICs in neuronal activity are poorly understood. However, there are two exceptions, namely, the straightforward role of ASICs in proton-based synaptic transmission in certain brain areas and the role of the Ca(2+)-permeable ASIC1a subtype in ischaemic cell death. Using a novel orthosteric ASIC antagonist, we have found that ASICs specifically control the frequency of spontaneous inhibitory synaptic activity in the hippocampus. Inhibition of ASICs leads to a strong increase in the frequency of spontaneous inhibitory postsynaptic currents. This effect is presynaptic because it is fully reproducible in single synaptic boutons attached to isolated hippocampal neurons. In concert with this observation, inhibition of the ASIC current diminishes epileptic discharges in a low Mg(2+) model of epilepsy in hippocampal slices and significantly reduces kainate-induced discharges in the hippocampus in vivo Our results reveal a significant novel role for ASICs.This article is part of the themed issue 'Evolution brings Ca(2+) and ATP together to control life and death'.
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Affiliation(s)
- O Ievglevskyi
- Department of Cellular Membranology, Bogomoletz Institute of Physiology, 01024 Kyiv, Ukraine
| | - D Isaev
- Department of Cellular Membranology, Bogomoletz Institute of Physiology, 01024 Kyiv, Ukraine
| | - O Netsyk
- Department of Cellular Membranology, Bogomoletz Institute of Physiology, 01024 Kyiv, Ukraine
| | - A Romanov
- Department of Cellular Membranology, Bogomoletz Institute of Physiology, 01024 Kyiv, Ukraine
| | - M Fedoriuk
- Department of Cellular Membranology, Bogomoletz Institute of Physiology, 01024 Kyiv, Ukraine
| | - O Maximyuk
- Department of Cellular Membranology, Bogomoletz Institute of Physiology, 01024 Kyiv, Ukraine
| | - E Isaeva
- Department of Cellular Membranology, Bogomoletz Institute of Physiology, 01024 Kyiv, Ukraine
| | - N Akaike
- Research Division for Clinical Pharmacology, Medical Corporation, JyuryoGroup, Kumamoto Kinoh Hospital, 6-8-1 Yamamuro, Kitaku, Kumamoto 860-8518, Japan
| | - O Krishtal
- Department of Cellular Membranology, Bogomoletz Institute of Physiology, 01024 Kyiv, Ukraine
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Tian Y, Bresenitz P, Reska A, El Moussaoui L, Beier CP, Gründer S. Glioblastoma cancer stem cell lines express functional acid sensing ion channels ASIC1a and ASIC3. Sci Rep 2017; 7:13674. [PMID: 29057936 PMCID: PMC5651884 DOI: 10.1038/s41598-017-13666-9] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Accepted: 09/29/2017] [Indexed: 12/18/2022] Open
Abstract
Acidic microenvironment is commonly observed in tumour tissues, including glioblastoma (GBM), the most aggressive and lethal brain tumour in adults. Acid sensing ion channels (ASICs) are neuronal voltage-insensitive sodium channels, which are sensors of extracellular protons. Here we studied and functionally characterized ASICs in two primary glioblastoma stem cell lines as cell culture models. We detected transcripts of the ACCN2 and ACCN3 genes, coding for ASIC1 and ASIC3, respectively, but not transcripts of ACCN1 (coding for ASIC2). Available microarray data confirmed that ACCN1 is downregulated in glioma. Western blotting confirmed expression of ASIC1 and ASIC3, the most proton-sensitive ASICs, in both GBM cell lines. We characterized ASICs functionally using whole-cell patch clamp and detected different types of acid-sensitive currents. Some of these currents had kinetics typical for ASICs and were sensitive to specific toxin inhibitors of ASIC1a or ASIC3, demonstrating that the GBM cell lines express functional ASIC1a and ASIC3 that may enable GBM cells to sensitively detect extracellular pH in a tumour tissue. Microarray data revealed that expression of ACCN2 and ACCN3 is associated with improved survival of patients suffering from gliomas, suggesting that preserved susceptibility to extracellular pH may impair tumour growth.
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Affiliation(s)
- Yuemin Tian
- Institute of Physiology, RWTH Aachen University, Pauwelsstrasse 30, D-52074, Aachen, Germany
| | - Pia Bresenitz
- Institute of Physiology, RWTH Aachen University, Pauwelsstrasse 30, D-52074, Aachen, Germany
| | - Anna Reska
- Institute of Physiology, RWTH Aachen University, Pauwelsstrasse 30, D-52074, Aachen, Germany
| | - Laila El Moussaoui
- Institute of Physiology, RWTH Aachen University, Pauwelsstrasse 30, D-52074, Aachen, Germany
| | - Christoph Patrick Beier
- Department of Neurology, RWTH Aachen University, Pauwelsstrasse 30, D-52074, Aachen, Germany.,Department of Neurology and Department of Clinical Research, Odense University Hospital and University of Southern Denmark, Sdr. Boulevard 20, 5000 Odense C, Denmark
| | - Stefan Gründer
- Institute of Physiology, RWTH Aachen University, Pauwelsstrasse 30, D-52074, Aachen, Germany.
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Effect of an Acid-sensing Ion Channels Inhibitor on Pain-related Behavior by Nucleus Pulposus Applied on the Nerve Root in Rats. Spine (Phila Pa 1976) 2017; 42:E633-E641. [PMID: 27879566 DOI: 10.1097/brs.0000000000001918] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN Controlled, interventional animal study. OBJECTIVE To examine the effect of an inhibitor of acid-sensing ion channel 3 (ASIC3) on pain-related behavior induced by application of the nucleus pulposus (NP) onto the dorsal root ganglion (DRG) in rats. SUMMARY OF BACKGROUND DATA ASIC3 is associated with acidosis pain in inflamed or ischemic tissues and is expressed in sensory neurons and NP cells. The ASIC3 inhibitor, APETx2, increases the mechanical threshold of pain in models of knee osteoarthritis or postoperative pain. However, the efficacy of APETx2 for pain relief in the NP application model remains unknown. METHODS Autologous NP was applied to the left L5 nerve root of 183 adult female Sprague-Dawley rats. The DRGs were treated with NP plus one of the following four treatments: saline solution (SM), low (0.01 μg: LD), medium (0.1 μg: MD), or high dose (1.0 μg: HD) of APETx2. Behavioral testing was performed to investigate the mechanical withdrawal threshold using von Frey hairs. Expression of nerve growth factor, hypoxia-inducible factor-1α (HIF1α), activating transcription factor-3, and ionized calcium-binding adaptor molecule-1 was evaluated using immunohistochemistry. Statistical differences among multiple groups were assessed using the Steel test, the Tukey-Kramer test, and the Dunnett test. P < 0.05 were considered significant. RESULTS The thresholds in the HD group were higher than those in the SM group at Days 14 and 21 (P < 0.05). In the MD group, the threshold was higher than in the SM group at Day 14 (P < 0.05). High doses of APETx2 reduced the expression of HIF1α after Day 14 compared with the SM group (P < 0.05). CONCLUSION APETx2 significantly improved pain-related behavior in a dose-dependent manner. APETx2 may inhibit ASIC3 and partly inhibit Nav1.8 channels. This ASIC3 channel inhibitor may be a potential therapeutic agent in early-stage lumbar disc herniation. LEVEL OF EVIDENCE N/A.
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Randhawa PK, Jaggi AS. A Review on Potential Involvement of TRPV1 Channels in Ischemia–Reperfusion Injury. J Cardiovasc Pharmacol Ther 2017; 23:38-45. [DOI: 10.1177/1074248417707050] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Besides functioning as thermosensors, transient receptor potential vanilloid 1 (TRPV1) channels play a pivotal role in ischemia–reperfusion injury. Transient receptor potential vanilloid 1 channel activation attenuates ischemia–reperfusion-induced injury in various organs including the heart, lungs, kidneys, and the brain. Transient receptor potential vanilloid 1 channels are expressed on the sensory neurons innervating the myocardium, ventricles of the heart, epicardial surface of the heart, endothelial cells, and the vascular smooth muscle cells. During ischemic conditions, activation of TRPV1 channels on the perivascular nerves stimulates the release of calcitonin gene-related peptide and substance P to produce cardioprotection. Furthermore, TRPV1 channel activation reduces the generation of free radicals and inflammatory cytokines, inhibits neutrophil infiltration, and enhances the production of anti-inflammatory cytokines to reduce ischemia–reperfusion-induced tissue injury. The present review describes the potential involvement of TRPV1 channels and the signaling cascade in attenuating ischemia–reperfusion injury in various organs.
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Affiliation(s)
- Puneet Kaur Randhawa
- Department of Pharmaceutical Sciences and Drug Research, Punjabi University Patiala, Patiala, Punjab, India
| | - Amteshwar Singh Jaggi
- Department of Pharmaceutical Sciences and Drug Research, Punjabi University Patiala, Patiala, Punjab, India
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Targeting ASIC3 for Relieving Mice Fibromyalgia Pain: Roles of Electroacupuncture, Opioid, and Adenosine. Sci Rep 2017; 7:46663. [PMID: 28440280 PMCID: PMC5404229 DOI: 10.1038/srep46663] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Accepted: 03/21/2017] [Indexed: 01/19/2023] Open
Abstract
Many scientists are seeking better therapies for treating fibromyalgia (FM) pain. We used a mouse model of FM to determine if ASIC3 and its relevant signaling pathway participated in FM pain. We demonstrated that FM-induced mechanical hyperalgesia was attenuated by electroacupuncture (EA). The decrease in fatigue-induced lower motor function in FM mice was also reversed by EA. These EA-based effects were abolished by the opioid receptor antagonist naloxone and the adenosine A1 receptor antagonist rolofylline. Administration of opioid receptor agonist endomorphin (EM) or adenosine A1 receptor agonist N6-cyclopentyladenosine (CPA) has similar results to EA. Similar results were also observed in ASIC3−/− or ASIC3 antagonist (APETx2) injected mice. Using western blotting, we determined that pPKA, pPI3K, and pERK were increased during a dual acidic injection priming period. Nociceptive receptors, such as ASIC3, Nav1.7, and Nav1.8, were upregulated in the dorsal root ganglion (DRG) and spinal cord (SC) of FM mice. Furthermore, pPKA, pPI3K, and pERK were increased in the central thalamus. These aforementioned mechanisms were completely abolished in ASIC3 knockout mice. Electrophysiological results also indicated that acid potentiated Nav currents through ASIC3 and ERK pathway. Our results highlight the crucial role of ASIC3-mediated mechanisms in the treatment of FM-induced mechanical hyperalgesia.
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Identification of a cono-RFamide from the venom of Conus textile that targets ASIC3 and enhances muscle pain. Proc Natl Acad Sci U S A 2017; 114:E3507-E3515. [PMID: 28396446 DOI: 10.1073/pnas.1616232114] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Acid-sensing ion channels (ASICs) are proton-gated Na+ channels that are expressed throughout the nervous system. ASICs have been implicated in several neuronal disorders, like ischemic stroke, neuronal inflammation, and pathological pain. Several toxins from venomous animals have been identified that target ASICs with high specificity and potency. These toxins are extremely useful in providing protein pharmacophores and to characterize function and structure of ASICs. Marine cone snails contain a high diversity of toxins in their venom such as conotoxins, which are short polypeptides stabilized by disulfide bonds, and conopeptides, which have no or only one disulfide bond. Whereas conotoxins selectively target specific neuronal proteins, mainly ion channels, the targets of conopeptides are less well known. Here, we perform an in vitro screen of venoms from 18 cone snail species to identify toxins targeting ASICs. We identified a small conopeptide of only four amino acids from the venom of Conus textile that strongly potentiated currents of ASIC3, which has a specific role in the pain pathway. This peptide, RPRFamide, belongs to the subgroup of cono-RFamides. Electrophysiological characterization of isolated dorsal root ganglion (DRG) neurons revealed that RPRFamide increases their excitability. Moreover, injection of the peptide into the gastrocnemius muscle strongly enhanced acid-induced muscle pain in mice that was abolished by genetic inactivation of ASIC3. In summary, we identified a conopeptide that targets the nociceptor-specific ion channel ASIC3.
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40
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Han JE, Cho JH, Choi IS, Kim DY, Jang IS. Effects of acidic pH on voltage-gated ion channels in rat trigeminal mesencephalic nucleus neurons. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY : OFFICIAL JOURNAL OF THE KOREAN PHYSIOLOGICAL SOCIETY AND THE KOREAN SOCIETY OF PHARMACOLOGY 2017; 21:215-223. [PMID: 28280415 PMCID: PMC5343055 DOI: 10.4196/kjpp.2017.21.2.215] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Revised: 01/10/2017] [Accepted: 01/18/2017] [Indexed: 11/15/2022]
Abstract
The effects of acidic pH on several voltage-dependent ion channels, such as voltage-dependent K+ and Ca2+ channels, and hyperpolarization-gated and cyclic nucleotide-activated cation (HCN) channels, were examined using a whole-cell patch clamp technique on mechanically isolated rat mesencephalic trigeminal nucleus neurons. The application of a pH 6.5 solution had no effect on the peak amplitude of voltage-dependent K+ currents. A pH 6.0 solution slightly, but significantly inhibited the peak amplitude of voltage-dependent K+ currents. The pH 6.0 also shifted both the current-voltage and conductance-voltage relationships to the depolarization range. The application of a pH 6.5 solution scarcely affected the peak amplitude of membrane currents mediated by HCN channels, which were profoundly inhibited by the general HCN channel blocker Cs+ (1 mM). However, the pH 6.0 solution slightly, but significantly inhibited the peak amplitude of HCN-mediated currents. Although the pH 6.0 solution showed complex modulation of the current-voltage and conductance-voltage relationships, the midpoint voltages for the activation of HCN channels were not changed by acidic pH. On the other hand, voltage-dependent Ca2+ channels were significantly inhibited by an acidic pH. The application of an acidic pH solution significantly shifted the current-voltage and conductance-voltage relationships to the depolarization range. The modulation of several voltage-dependent ion channels by an acidic pH might affect the excitability of mesencephalic trigeminal nucleus neurons, and thus physiological functions mediated by the mesencephalic trigeminal nucleus could be affected in acidic pH conditions.
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Affiliation(s)
- Jin-Eon Han
- Department of Pharmacology, School of Dentistry, Kyungpook National University, Daegu 41940, Korea
| | - Jin-Hwa Cho
- Department of Pharmacology, School of Dentistry, Kyungpook National University, Daegu 41940, Korea
| | - In-Sun Choi
- Department of Pharmacology, School of Dentistry, Kyungpook National University, Daegu 41940, Korea
| | - Do-Yeon Kim
- Department of Pharmacology, School of Dentistry, Kyungpook National University, Daegu 41940, Korea.; Brain Science & Engineering Institute, Kyungpook National University, Daegu 41940, Korea
| | - Il-Sung Jang
- Department of Pharmacology, School of Dentistry, Kyungpook National University, Daegu 41940, Korea.; Brain Science & Engineering Institute, Kyungpook National University, Daegu 41940, Korea
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41
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Abdelhamid RE, Sluka KA. ASICs Mediate Pain and Inflammation in Musculoskeletal Diseases. Physiology (Bethesda) 2016; 30:449-59. [PMID: 26525344 DOI: 10.1152/physiol.00030.2015] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Chronic musculoskeletal pain is debilitating and affects ∼ 20% of adults. Tissue acidosis is present in painful musculoskeletal diseases like rheumatoid arthritis. ASICs are located on skeletal muscle and joint nociceptors as well as on nonneuronal cells in the muscles and joints, where they mediate nociception. This review discusses the properties of different types of ASICs, factors affecting their pH sensitivity, and their role in musculoskeletal hyperalgesia and inflammation.
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Affiliation(s)
- Ramy E Abdelhamid
- Department of Physical Therapy and Rehabilitation Science, Neuroscience Graduate Program, Pain Research Program, University of Iowa, Iowa City, Iowa
| | - Kathleen A Sluka
- Department of Physical Therapy and Rehabilitation Science, Neuroscience Graduate Program, Pain Research Program, University of Iowa, Iowa City, Iowa
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Ergonul Z, Yang L, Palmer LG. Properties of acid-induced currents in mouse dorsal root ganglia neurons. Physiol Rep 2016; 4:4/9/e12795. [PMID: 27173673 PMCID: PMC4873640 DOI: 10.14814/phy2.12795] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Accepted: 04/15/2016] [Indexed: 11/29/2022] Open
Abstract
Acid‐sensing ion channels (ASICs) are cation channels that are activated by protons (H+). They are expressed in neurons throughout the nervous system and may play important roles in several neurologic disorders including inflammation, cerebral ischemia, seizures, neurodegeneration, anxiety, depression, and migraine. ASICs generally produce transient currents that desensitize in response to a decrease in extracellular pH. Under certain conditions, the inactivation of ASICs can be incomplete and allow them to produce sustained currents. Here, we characterize the properties of both transient and sustained acid‐induced currents in cultured mouse dorsal root ganglia (DRG) neurons. At pH levels between 7.3 and 7.1 they include “window currents” through ASICs. With stronger acid signals sustained currents are maintained in the absence of extracellular Na+ or the presence of the ASIC blockers amiloride and Psalmotoxin‐1(PcTx1). These sustained responses may have several different origins in these cells, including acid‐induced stimulation of inward Cl− currents, block of outward K+ currents, and augmentation of inward H+ currents, properties that distinguish these novel sustained currents from the well‐characterized transient currents.
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Affiliation(s)
- Zuhal Ergonul
- Department of Physiology and Biophysics, Weill Cornell Medical College, New York, New York Department of Pediatrics, NewYork-Presbyterian/Weill Cornell Medical Center, New York, New York
| | - Lei Yang
- Department of Physiology and Biophysics, Weill Cornell Medical College, New York, New York Department of Physiology, Harbin Medical University, Harbin, China
| | - Lawrence G Palmer
- Department of Physiology and Biophysics, Weill Cornell Medical College, New York, New York
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Joeres N, Augustinowski K, Neuhof A, Assmann M, Gründer S. Functional and pharmacological characterization of two different ASIC1a/2a heteromers reveals their sensitivity to the spider toxin PcTx1. Sci Rep 2016; 6:27647. [PMID: 27277303 PMCID: PMC4899722 DOI: 10.1038/srep27647] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Accepted: 05/24/2016] [Indexed: 12/23/2022] Open
Abstract
Acid Sensing Ion Channels (ASICs) detect extracellular proton signals and are involved in synaptic transmission and pain sensation. ASIC subunits assemble into homo- and heteromeric channels composed of three subunits. Single molecule imaging revealed that heteromers composed of ASIC1a and ASIC2a, which are widely expressed in the central nervous system, have a flexible 2:1/1:2 stoichiometry. It was hitherto not possible, however, to functionally differentiate these two heteromers. To have a homogenous population of ASIC1a/2a heteromers with either 2:1 or 1:2 stoichiometry, we covalently linked subunits in the desired configuration and characterized their functional properties in Xenopus oocytes. We show that the two heteromers have slightly different proton affinity, with an additional ASIC1a subunit increasing apparent affinity. Moreover, we found that zinc, which potentiates ASIC2a-containing ASICs but not homomeric ASIC1a, potentiates both heteromers. Finally, we show that PcTx1, which binds at subunit-subunit interfaces of homomeric ASIC1a, inhibits both heteromers suggesting that ASIC2a can also contribute to a PcTx1 binding site. Using this functional fingerprint, we show that rat cortical neurons predominantly express the ASIC1a/2a heteromer with a 2:1 stoichiometry. Collectively, our results reveal the contribution of individual subunits to the functional properties of ASIC1a/2a heteromers.
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Affiliation(s)
- Niko Joeres
- Institute of Physiology, RWTH Aachen University, Pauwelsstrasse 30, D-52074 Aachen, Germany
| | - Katrin Augustinowski
- Institute of Physiology, RWTH Aachen University, Pauwelsstrasse 30, D-52074 Aachen, Germany
| | - Andreas Neuhof
- Institute of Physiology, RWTH Aachen University, Pauwelsstrasse 30, D-52074 Aachen, Germany
| | - Marc Assmann
- Institute of Physiology, RWTH Aachen University, Pauwelsstrasse 30, D-52074 Aachen, Germany
| | - Stefan Gründer
- Institute of Physiology, RWTH Aachen University, Pauwelsstrasse 30, D-52074 Aachen, Germany
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44
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Evidence for the involvement of ASIC3 in sensory mechanotransduction in proprioceptors. Nat Commun 2016; 7:11460. [PMID: 27161260 PMCID: PMC4866049 DOI: 10.1038/ncomms11460] [Citation(s) in RCA: 85] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Accepted: 03/29/2016] [Indexed: 01/12/2023] Open
Abstract
Acid-sensing ion channel 3 (ASIC3) is involved in acid nociception, but its possible role in neurosensory mechanotransduction is disputed. We report here the generation of Asic3-knockout/eGFPf-knockin mice and subsequent characterization of heterogeneous expression of ASIC3 in the dorsal root ganglion (DRG). ASIC3 is expressed in parvalbumin (Pv+) proprioceptor axons innervating muscle spindles. We further generate a floxed allele of Asic3 (Asic3f/f) and probe the role of ASIC3 in mechanotransduction in neurite-bearing Pv+ DRG neurons through localized elastic matrix movements and electrophysiology. Targeted knockout of Asic3 disrupts spindle afferent sensitivity to dynamic stimuli and impairs mechanotransduction in Pv+ DRG neurons because of substrate deformation-induced neurite stretching, but not to direct neurite indentation. In behavioural tasks, global knockout (Asic3−/−) and Pv-Cre::Asic3f/f mice produce similar deficits in grid and balance beam walking tasks. We conclude that, at least in mouse, ASIC3 is a molecular determinant contributing to dynamic mechanosensitivity in proprioceptors. Acid-sensing ion channel 3 (ASIC3) is known to play a role in nociception, but its role in low threshold neurosensory mechanotransduction is unclear. Here, the authors target ASIC3 expression in dorsal root ganglion parvalbumin positive neurons and find ASIC3 contributes to dynamic proprioception responses.
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45
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MacLean DM, Jayaraman V. Acid-sensing ion channels are tuned to follow high-frequency stimuli. J Physiol 2016; 594:2629-45. [PMID: 26931316 DOI: 10.1113/jp271915] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Accepted: 02/27/2016] [Indexed: 01/26/2023] Open
Abstract
KEY POINTS Acid-sensing ion channels (ASICs) act as neurotransmitter receptors by responding to synaptic cleft acidification. We investigated how ASIC1a homomers and ASIC1a/2a heteromers respond to brief stimuli, jumping from pH 8.0 to 5.0, approximating the time course of neurotransmitter in the cleft. We find that ASICs deactivate surprisingly fast in response to such brief stimuli from pH 8.0 to 5.0, whereas they desensitize comparatively slowly to prolonged activation. The combination of unusually fast deactivation with slow desensitzation enables recombinant ASIC1a homomers and ASIC1a/2a heteromers, as well as native ASICs of sensory neurons, to follow trains of such brief pH 8.0 to 5.0 stimuli at high frequencies. This capacity for high-frequency signalling persists under a physiological pH of 7.4 with ASIC1a/2a heteromers, suggesting that they may sustain postsynaptic responses when other receptors desensitize. ABSTRACT The neurotransmitter-gated ion channels that underlie rapid synaptic transmission are often subjected to bursts of very brief neurotransmitter release at high frequencies. When challenged with such short duration high-frequency stimuli, neurotransmitter-gated ion channels generally exhibit the common response of desensitization. Recently, acid-sensing ion channels (ASICs) were shown to act as neurotransmitter-gated ion channels because postsynaptic ASICs can be activated by the transient acidification of the synaptic cleft accompanying neurotransmission. In the present study, we examined the responses of recombinant ASIC1a homomers, ASIC1a/2a heteromers and native ASICs from sensory neurons to 1 ms acidification stimuli, switching from pH 8.0 to 5.0, as either single pulses or trains of pulses at physiologically relevant frequencies. We found that ASIC deactivation is extremely fast and, in contrast to most other neurotransmitter-gated ion channels, ASICs show no desensitization during high-frequency stimulus trains under these conditions. We also found that accelerating ASIC desensitization by anion substitution can induce depression during high-frequency trains. When using a baseline physiological pH of 7.4, the ASIC1a responses were too small to reliably measure, presumably as a result of steady-state desensitization. However, ASIC1a/2 heteromers gave robust responses when using a baseline pH of 7.4 and were also able to sustain these responses during high-frequency stimulus trains. In conclusion, we report that the slow desensitization and fast deactivation of ASIC1a/2a heteromers enables them to sustain postsynaptic responses to bursts at high frequencies at a physiological pH that may desensitize other receptors.
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Affiliation(s)
- David M MacLean
- Center for Membrane Biology, Department of Biochemistry and Molecular Biology, University of Texas Health Science Center, Houston, TX, USA
| | - Vasanthi Jayaraman
- Center for Membrane Biology, Department of Biochemistry and Molecular Biology, University of Texas Health Science Center, Houston, TX, USA
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da Silva Serra I, Husson Z, Bartlett JD, Smith ESJ. Characterization of cutaneous and articular sensory neurons. Mol Pain 2016; 12:1744806916636387. [PMID: 27030722 PMCID: PMC4956179 DOI: 10.1177/1744806916636387] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Accepted: 02/02/2016] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND A wide range of stimuli can activate sensory neurons and neurons innervating specific tissues often have distinct properties. Here, we used retrograde tracing to identify sensory neurons innervating the hind paw skin (cutaneous) and ankle/knee joints (articular), and combined immunohistochemistry and electrophysiology analysis to determine the neurochemical phenotype of cutaneous and articular neurons, as well as their electrical and chemical excitability. RESULTS Immunohistochemistry analysis using RetroBeads as a retrograde tracer confirmed previous data that cutaneous and articular neurons are a mixture of myelinated and unmyelinated neurons, and the majority of both populations are peptidergic. In whole-cell patch-clamp recordings from cultured dorsal root ganglion neurons, voltage-gated inward currents and action potential parameters were largely similar between articular and cutaneous neurons, although cutaneous neuron action potentials had a longer half-peak duration (HPD). An assessment of chemical sensitivity showed that all neurons responded to a pH 5.0 solution, but that acid-sensing ion channel (ASIC) currents, determined by inhibition with the nonselective acid-sensing ion channel antagonist benzamil, were of a greater magnitude in cutaneous compared to articular neurons. Forty to fifty percent of cutaneous and articular neurons responded to capsaicin, cinnamaldehyde, and menthol, indicating similar expression levels of transient receptor potential vanilloid 1 (TRPV1), transient receptor potential ankyrin 1 (TRPA1), and transient receptor potential melastatin 8 (TRPM8), respectively. By contrast, significantly more articular neurons responded to ATP than cutaneous neurons. CONCLUSION This work makes a detailed characterization of cutaneous and articular sensory neurons and highlights the importance of making recordings from identified neuronal populations: sensory neurons innervating different tissues have subtly different properties, possibly reflecting different functions.
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Affiliation(s)
- Ines da Silva Serra
- Department of Pharmacology, University of Cambridge, Cambridge, UK School of Psychology and Clinical Language Sciences, University of Reading, Reading, UK
| | - Zoé Husson
- Department of Pharmacology, University of Cambridge, Cambridge, UK
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Marra S, Ferru-Clément R, Breuil V, Delaunay A, Christin M, Friend V, Sebille S, Cognard C, Ferreira T, Roux C, Euller-Ziegler L, Noel J, Lingueglia E, Deval E. Non-acidic activation of pain-related Acid-Sensing Ion Channel 3 by lipids. EMBO J 2016; 35:414-28. [PMID: 26772186 DOI: 10.15252/embj.201592335] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Accepted: 12/07/2015] [Indexed: 12/21/2022] Open
Abstract
Extracellular pH variations are seen as the principal endogenous signal that triggers activation of Acid-Sensing Ion Channels (ASICs), which are basically considered as proton sensors, and are involved in various processes associated with tissue acidification. Here, we show that human painful inflammatory exudates, displaying non-acidic pH, induce a slow constitutive activation of human ASIC3 channels. This effect is largely driven by lipids, and we identify lysophosphatidylcholine (LPC) and arachidonic acid (AA) as endogenous activators of ASIC3 in the absence of any extracellular acidification. The combination of LPC and AA evokes robust depolarizing current in DRG neurons at physiological pH 7.4, increases nociceptive C-fiber firing, and induces pain behavior in rats, effects that are all prevented by ASIC3 blockers. Lipid-induced pain is also significantly reduced in ASIC3 knockout mice. These findings open new perspectives on the roles of ASIC3 in the absence of tissue pH variation, as well as on the contribution of those channels to lipid-mediated signaling.
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Affiliation(s)
- Sébastien Marra
- CNRS, Institut de Pharmacologie Moléculaire et Cellulaire (IPMC), UMR 7275, Valbonne, France Université de Nice Sophia Antipolis, UMR 7275, Valbonne, France LabEx Ion Channel Science and Therapeutics, Valbonne, France
| | - Romain Ferru-Clément
- CNRS, Laboratoire de Signalisation et Transports Ioniques Membranaires (STIM), ERL 7368, Poitiers Cedex 9, France Université de Poitiers, ERL 7368, Poitiers Cedex 9, France
| | | | - Anne Delaunay
- CNRS, Institut de Pharmacologie Moléculaire et Cellulaire (IPMC), UMR 7275, Valbonne, France Université de Nice Sophia Antipolis, UMR 7275, Valbonne, France LabEx Ion Channel Science and Therapeutics, Valbonne, France
| | - Marine Christin
- CNRS, Institut de Pharmacologie Moléculaire et Cellulaire (IPMC), UMR 7275, Valbonne, France Université de Nice Sophia Antipolis, UMR 7275, Valbonne, France LabEx Ion Channel Science and Therapeutics, Valbonne, France
| | - Valérie Friend
- CNRS, Institut de Pharmacologie Moléculaire et Cellulaire (IPMC), UMR 7275, Valbonne, France Université de Nice Sophia Antipolis, UMR 7275, Valbonne, France LabEx Ion Channel Science and Therapeutics, Valbonne, France
| | - Stéphane Sebille
- CNRS, Laboratoire de Signalisation et Transports Ioniques Membranaires (STIM), ERL 7368, Poitiers Cedex 9, France Université de Poitiers, ERL 7368, Poitiers Cedex 9, France
| | - Christian Cognard
- CNRS, Laboratoire de Signalisation et Transports Ioniques Membranaires (STIM), ERL 7368, Poitiers Cedex 9, France Université de Poitiers, ERL 7368, Poitiers Cedex 9, France
| | - Thierry Ferreira
- CNRS, Laboratoire de Signalisation et Transports Ioniques Membranaires (STIM), ERL 7368, Poitiers Cedex 9, France Université de Poitiers, ERL 7368, Poitiers Cedex 9, France
| | | | | | - Jacques Noel
- CNRS, Institut de Pharmacologie Moléculaire et Cellulaire (IPMC), UMR 7275, Valbonne, France Université de Nice Sophia Antipolis, UMR 7275, Valbonne, France LabEx Ion Channel Science and Therapeutics, Valbonne, France
| | - Eric Lingueglia
- CNRS, Institut de Pharmacologie Moléculaire et Cellulaire (IPMC), UMR 7275, Valbonne, France Université de Nice Sophia Antipolis, UMR 7275, Valbonne, France LabEx Ion Channel Science and Therapeutics, Valbonne, France
| | - Emmanuel Deval
- CNRS, Institut de Pharmacologie Moléculaire et Cellulaire (IPMC), UMR 7275, Valbonne, France Université de Nice Sophia Antipolis, UMR 7275, Valbonne, France LabEx Ion Channel Science and Therapeutics, Valbonne, France
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Acid-sensing ion channel (ASIC) 4 predominantly localizes to an early endosome-related organelle upon heterologous expression. Sci Rep 2015; 5:18242. [PMID: 26667795 PMCID: PMC4678866 DOI: 10.1038/srep18242] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2015] [Accepted: 10/23/2015] [Indexed: 12/25/2022] Open
Abstract
Acid-sensing ion channels (ASICs) are voltage-independent proton-gated amiloride sensitive sodium channels, belonging to the DEG/ENaC gene family. Six different ASICs have been identified (ASIC1a, ASIC1b, ASIC2a, ASIC2b, ASIC3, ASIC4) that are activated by a drop in extracellular pH, either as homo- or heteromers. An exception is ASIC4, which is not activated by protons as a homomer and which does not contribute to functional heteromeric ASICs. Insensitivity of ASIC4 to protons and its comparatively low sequence identity to other ASICs (45%) raises the question whether ASIC4 may have different functions than other ASICs. In this study, we therefore investigated the subcellular localization of ASIC4 in heterologous cell lines, which revealed a surprising accumulation of the channel in early endosome-related vacuoles. Moreover, we identified an unique amino-terminal motif as important for forward-trafficking from the ER/Golgi to the early endosome-related compartment. Collectively, our results show that heterologously expressed ASIC4 predominantly resides in an intracellular endosomal compartment.
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Radu BM, Banciu A, Banciu DD, Radu M. Acid-Sensing Ion Channels as Potential Pharmacological Targets in Peripheral and Central Nervous System Diseases. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2015; 103:137-67. [PMID: 26920689 DOI: 10.1016/bs.apcsb.2015.10.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Acid-sensing ion channels (ASICs) are widely expressed in the body and represent good sensors for detecting protons. The pH drop in the nervous system is equivalent to ischemia and acidosis, and ASICs are very good detectors in discriminating slight changes in acidity. ASICs are important pharmacological targets being involved in a variety of pathophysiological processes affecting both the peripheral nervous system (e.g., peripheral pain, diabetic neuropathy) and the central nervous system (e.g., stroke, epilepsy, migraine, anxiety, fear, depression, neurodegenerative diseases, etc.). This review discusses the role played by ASICs in different pathologies and the pharmacological agents acting on ASICs that might represent promising drugs. As the majority of above-mentioned pathologies involve not only neuronal dysfunctions but also microvascular alterations, in the next future, ASICs may be also considered as potential pharmacological targets at the vasculature level. Perspectives and limitations in the use of ASICs antagonists and modulators as pharmaceutical agents are also discussed.
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Affiliation(s)
- Beatrice Mihaela Radu
- Department of Neurological and Movement Sciences, Section of Anatomy and Histology, University of Verona, Verona, Italy; Department of Anatomy, Animal Physiology and Biophysics, Faculty of Biology, University of Bucharest, Bucharest, Romania
| | - Adela Banciu
- Department of Anatomy, Animal Physiology and Biophysics, Faculty of Biology, University of Bucharest, Bucharest, Romania
| | - Daniel Dumitru Banciu
- Department of Anatomy, Animal Physiology and Biophysics, Faculty of Biology, University of Bucharest, Bucharest, Romania
| | - Mihai Radu
- Department of Neurological and Movement Sciences, Section of Anatomy and Histology, University of Verona, Verona, Italy; Department of Life and Environmental Physics, 'Horia Hulubei' National Institute for Physics and Nuclear Engineering, Magurele, Romania.
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Abstract
Sensory nerve fibers innervating the ocular anterior surface detect external stimuli producing innocuous and painful sensations. Protons are among the first mediators released by damaged cells during inflammation, tissue injury, or other chronic ophthalmic conditions. We studied whether acid-sensing ion channels (ASICs) are expressed in corneal sensory neurons and their roles in the response to moderate acidifications of the ocular surface and in pathologies producing ocular surface inflammation. Moderate acidic pH (6.6) activated ASIC-like currents in corneal sensory neurons, which were blocked by ASIC1- or ASIC3-specific toxins. Acidic pH depolarizes corneal sensory neurons to fire action potentials, an effect blocked by the ASIC3 inhibitor APETx2. 2-Guanidino-4-methylquinazoline, an ASIC3 agonist, activated a population of corneal polymodal sensory nerve fibers and significantly increased the blinking and tearing rate. The nocifensive behaviors produced by application of either a moderate acidic stimulus or ophthalmic drugs formulated in acidic solution were abolished by ASIC blockers. In a model of allergic keratoconjunctivitis, nocifensive behavior was greatly reduced by ASIC3 blockade, presumably by reducing nociceptor sensitization during the inflammatory process. Our results show that, in addition to the established role of TRPV1, ASICs play a significant role in the detection of acidic insults at the ocular surface. The identification of ASICs in corneal neurons and their alterations during different diseases is critical for the understanding of sensory ocular pathophysiology. They are likely to mediate some of the discomfort sensations accompanying several ophthalmic formulations and may represent novel targets for the development of new therapeutics for ocular pathologies.
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