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Okada Y. Physiology of the volume-sensitive/regulatory anion channel VSOR/VRAC: part 2: its activation mechanisms and essential roles in organic signal release. J Physiol Sci 2024; 74:34. [PMID: 38877402 PMCID: PMC11177392 DOI: 10.1186/s12576-024-00926-3] [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: 05/05/2024] [Accepted: 06/01/2024] [Indexed: 06/16/2024]
Abstract
The volume-sensitive outwardly rectifying or volume-regulated anion channel, VSOR/VRAC, which was discovered in 1988, is expressed in most vertebrate cell types, and is essentially involved in cell volume regulation after swelling and in the induction of cell death. This series of review articles describes what is already known and what remains to be uncovered about the functional and molecular properties as well as the physiological and pathophysiological roles of VSOR/VRAC. This Part 2 review article describes, from the physiological and pathophysiological standpoints, first the pivotal roles of VSOR/VRAC in the release of autocrine/paracrine organic signal molecules, such as glutamate, ATP, glutathione, cGAMP, and itaconate, as well as second the swelling-independent and -dependent activation mechanisms of VSOR/VRAC. Since the pore size of VSOR/VRAC has now well been evaluated by electrophysiological and 3D-structural methods, the signal-releasing activity of VSOR/VRAC is here discussed by comparing the molecular sizes of these organic signals to the channel pore size. Swelling-independent activation mechanisms include a physicochemical one caused by the reduction of intracellular ionic strength and a biochemical one caused by oxidation due to stimulation by receptor agonists or apoptosis inducers. Because some organic substances released via VSOR/VRAC upon cell swelling can trigger or augment VSOR/VRAC activation in an autocrine fashion, swelling-dependent activation mechanisms are to be divided into two phases: the first phase induced by cell swelling per se and the second phase caused by receptor stimulation by released organic signals.
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Affiliation(s)
- Yasunobu Okada
- National Institute for Physiological Sciences (NIPS), 5-1 Higashiyama, Myodaiji, Okazaki, Aichi, 444-8787, Japan.
- Department of Integrative Physiology, Graduate School of Medicine, Akita University, Akita, Japan.
- Department of Physiology, School of Medicine, Aichi Medical University, Nagakute, Japan.
- Graduate University for Advanced Studies (SOKENDAI), Hayama, Kanagawa, Japan.
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2
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Knecht DA, Zeziulia M, Bhavsar MB, Puchkov D, Maier H, Jentsch TJ. LRRC8/VRAC volume-regulated anion channels are crucial for hearing. J Biol Chem 2024; 300:107436. [PMID: 38838775 DOI: 10.1016/j.jbc.2024.107436] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2024] [Revised: 05/09/2024] [Accepted: 05/23/2024] [Indexed: 06/07/2024] Open
Abstract
Hearing crucially depends on cochlear ion homeostasis as evident from deafness elicited by mutations in various genes encoding cation or anion channels and transporters. Ablation of ClC‑K/barttin chloride channels causes deafness by interfering with the positive electrical potential of the endolymph, but roles of other anion channels in the inner ear have not been studied. Here we report the intracochlear distribution of all five LRRC8 subunits of VRAC, a volume-regulated anion channel that transports chloride, metabolites, and drugs such as the ototoxic anti-cancer drug cisplatin, and explore its physiological role by ablating its subunits. Sensory hair cells express all LRRC8 isoforms, whereas only LRRC8A, D and E were found in the potassium-secreting epithelium of the stria vascularis. Cochlear disruption of the essential LRRC8A subunit, or combined ablation of LRRC8D and E, resulted in cochlear degeneration and congenital deafness of Lrrc8a-/- mice. It was associated with a progressive degeneration of the organ of Corti and its innervating spiral ganglion. Like disruption of ClC-K/barttin, loss of VRAC severely reduced the endocochlear potential. However, the mechanism underlying this reduction seems different. Disruption of VRAC, but not ClC-K/barttin, led to an almost complete loss of Kir4.1 (KCNJ10), a strial K+ channel crucial for the generation of the endocochlear potential. The strong downregulation of Kir4.1 might be secondary to a loss of VRAC-mediated transport of metabolites regulating inner ear redox potential such as glutathione. Our study extends the knowledge of the role of cochlear ion transport in hearing and ototoxicity.
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Affiliation(s)
- Deborah A Knecht
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany; Max-Delbrück-Centrum für Molekulare Medizin (MDC), Berlin, Germany
| | - Mariia Zeziulia
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany; Max-Delbrück-Centrum für Molekulare Medizin (MDC), Berlin, Germany; Graduate Program of the Freie Universität Berlin, Berlin, Germany
| | - Mit B Bhavsar
- Department of Otolaryngology, Hannover Medical School, Hannover, Germany
| | - Dmytro Puchkov
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany
| | - Hannes Maier
- Department of Otolaryngology, Hannover Medical School, Hannover, Germany; Cluster of Excellence "Hearing4all", Hannover, Germany
| | - Thomas J Jentsch
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany; NeuroCure Cluster of Excellence, Charité Universitätsmedizin Berlin, Berlin, Germany.
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Yoshie S, Murono S, Hazama A. Approach for Elucidating the Molecular Mechanism of Epithelial to Mesenchymal Transition in Fibrosis of Asthmatic Airway Remodeling Focusing on Cl - Channels. Int J Mol Sci 2023; 25:289. [PMID: 38203460 PMCID: PMC10779031 DOI: 10.3390/ijms25010289] [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: 10/31/2023] [Revised: 12/15/2023] [Accepted: 12/16/2023] [Indexed: 01/12/2024] Open
Abstract
Airway remodeling caused by asthma is characterized by structural changes of subepithelial fibrosis, goblet cell metaplasia, submucosal gland hyperplasia, smooth muscle cell hyperplasia, and angiogenesis, leading to symptoms such as dyspnea, which cause marked quality of life deterioration. In particular, fibrosis exacerbated by asthma progression is reportedly mediated by epithelial-mesenchymal transition (EMT). It is well known that the molecular mechanism of EMT in fibrosis of asthmatic airway remodeling is closely associated with several signaling pathways, including the TGF-β1/Smad, TGF-β1/non-Smad, and Wnt/β-catenin signaling pathways. However, the molecular mechanism of EMT in fibrosis of asthmatic airway remodeling has not yet been fully clarified. Given that Cl- transport through Cl- channels causes passive water flow and consequent changes in cell volume, these channels may be considered to play a key role in EMT, which is characterized by significant morphological changes. In the present article, we highlight how EMT, which causes fibrosis and carcinogenesis in various tissues, is strongly associated with activation or inactivation of Cl- channels and discuss whether Cl- channels can lead to elucidation of the molecular mechanism of EMT in fibrosis of asthmatic airway remodeling.
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Affiliation(s)
- Susumu Yoshie
- Department of Cellular and Integrative Physiology, Graduate School of Medicine, Fukushima Medical University, Fukushima 960-1295, Japan
| | - Shigeyuki Murono
- Department of Otolaryngology Head and Neck Surgery, Graduate School of Medicine, Fukushima Medical University, Fukushima 960-1295, Japan
| | - Akihiro Hazama
- Department of Cellular and Integrative Physiology, Graduate School of Medicine, Fukushima Medical University, Fukushima 960-1295, Japan
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Kukulage DSK, Yapa Abeywardana M, Matarage Don NNJ, Hu RM, Shishikura K, Matthews ML, Ahn YH. Chemoproteomic strategy identified p120-catenin glutathionylation regulates E-cadherin degradation and cell migration. Cell Chem Biol 2023; 30:1542-1556.e9. [PMID: 37714153 PMCID: PMC10840712 DOI: 10.1016/j.chembiol.2023.08.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 05/30/2023] [Accepted: 08/15/2023] [Indexed: 09/17/2023]
Abstract
Identification of cysteines with high oxidation susceptibility is important for understanding redox-mediated biological processes. In this report, we report a chemical proteomic strategy that finds cysteines with high susceptibility to S-glutathionylation. Our proteomic strategy, named clickable glutathione-based isotope-coded affinity tag (G-ICAT), identified 1,518 glutathionylated cysteines while determining their relative levels of glutathionylated and reduced forms upon adding hydrogen peroxide. Among identified cysteines, we demonstrated that CTNND1 (p120) C692 has high susceptibility to glutathionylation. Also, p120 wild type (WT), compared to C692S, induces its dissociation from E-cadherin under oxidative stress, such as glucose depletion. p120 and E-cadherin dissociation correlated with E-cadherin destabilization via its proteasomal degradation. Lastly, we showed that p120 WT, compared to C692S, increases migration and invasion of MCF7 cells under glucose depletion, supporting a model that p120 C692 glutathionylation increases cell migration and invasion by destabilization of E-cadherin, a core player in cell-cell adhesion.
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Affiliation(s)
| | | | | | - Ren-Ming Hu
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Kyosuke Shishikura
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Megan L Matthews
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Young-Hoon Ahn
- Department of Chemistry, Drexel University, Philadelphia, PA 19104, USA.
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Yang J, Liu J, Liang J, Li F, Wang W, Chen H, Xie X. Epithelial-mesenchymal transition in age-associated thymic involution: Mechanisms and therapeutic implications. Ageing Res Rev 2023; 92:102115. [PMID: 37922996 DOI: 10.1016/j.arr.2023.102115] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Revised: 10/17/2023] [Accepted: 10/29/2023] [Indexed: 11/07/2023]
Abstract
The thymus is a critical immune organ with endocrine and immune functions that plays important roles in the physiological and pathological processes of the body. However, with aging, the thymus undergoes degenerative changes leading to decreased production and output of naive T cells and the secretion of thymic hormones and related cytokines, thereby promoting the occurrence and development of various age-associated diseases. Therefore, identifying essential processes that regulate age-associated thymic involution is crucial for long-term control of thymic involution and age-associated disease progression. Epithelial-mesenchymal transition (EMT) is a well-established process involved in organ aging and functional impairment through tissue fibrosis in several organs, such as the heart and kidney. In the thymus, EMT promotes fibrosis and potentially adipogenesis, leading to thymic involution. This review focuses on the factors involved in thymic involution, including oxidative stress, inflammation, and hormones, from the perspective of EMT. Furthermore, current interventions for reversing age-associated thymic involution by targeting EMT-associated processes are summarized. Understanding the key mechanisms of thymic involution through EMT as an entry point may promote the development of new therapies and clinical agents to reverse thymic involution and age-associated disease.
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Affiliation(s)
- Jiali Yang
- The School of Basic Medical Sciences, Southwest Medical University, Luzhou, China; Public Center of Experimental Technology, Model Animal and Human Disease Research of Luzhou Key Laboratory, Southwest Medical University, Luzhou, China
| | - Juan Liu
- The School of Basic Medical Sciences, Southwest Medical University, Luzhou, China; Public Center of Experimental Technology, Model Animal and Human Disease Research of Luzhou Key Laboratory, Southwest Medical University, Luzhou, China
| | - Jiayu Liang
- The School of Basic Medical Sciences, Southwest Medical University, Luzhou, China; Public Center of Experimental Technology, Model Animal and Human Disease Research of Luzhou Key Laboratory, Southwest Medical University, Luzhou, China
| | - Fan Li
- The School of Basic Medical Sciences, Southwest Medical University, Luzhou, China; Public Center of Experimental Technology, Model Animal and Human Disease Research of Luzhou Key Laboratory, Southwest Medical University, Luzhou, China
| | - Wenwen Wang
- The School of Basic Medical Sciences, Southwest Medical University, Luzhou, China; Public Center of Experimental Technology, Model Animal and Human Disease Research of Luzhou Key Laboratory, Southwest Medical University, Luzhou, China
| | - Huan Chen
- The School of Basic Medical Sciences, Southwest Medical University, Luzhou, China; Nucleic Acid Medicine of Luzhou Key Laboratory, Southwest Medical University, Luzhou, China.
| | - Xiang Xie
- The School of Basic Medical Sciences, Southwest Medical University, Luzhou, China; Public Center of Experimental Technology, Model Animal and Human Disease Research of Luzhou Key Laboratory, Southwest Medical University, Luzhou, China.
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Wu X, Yi X, Zhao B, Zhi Y, Xu Z, Cao Y, Cao X, Pang J, Yung KKL, Zhang S, Liu S, Zhou P. The volume regulated anion channel VRAC regulates NLRP3 inflammasome by modulating itaconate efflux and mitochondria function. Pharmacol Res 2023; 198:107016. [PMID: 38006980 DOI: 10.1016/j.phrs.2023.107016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Revised: 11/19/2023] [Accepted: 11/22/2023] [Indexed: 11/27/2023]
Abstract
The NLRP3 inflammasome is a supramolecular complex that is linked to sterile and pathogen-dependent inflammation, and its excessive activation underlies many diseases. Ion flux disturbance and cell volume regulation are both reported to mediate NLRP3 inflammasome activation, but the underlying orchestrating signaling remains not fully elucidated. The volume-regulated anion channel (VRAC), formed by LRRC8 proteins, is an important constituent that controls cell volume by permeating chloride and organic osmolytes in response to cell swelling. We now demonstrate that Lrrc8a, the essential component of VRAC, plays a central and specific role in canonical NLRP3 inflammasome activation. Moreover, VRAC acts downstream of K+ efflux for NLRP3 stimuli that require K+ efflux. Mechanically, our data demonstrate that VRAC modulates itaconate efflux and damaged mitochondria production for NLRP3 inflammasome activation. Further in vivo experiments show mice with Lrrc8a deficiency in myeloid cells were protected from lipopolysaccharides (LPS)-induced endotoxic shock. Taken together, this work identifies VRAC as a key regulator of NLRP3 inflammasome and innate immunity by regulating mitochondrial adaption for macrophage activation and highlights VRAC as a prospective drug target for the treatment of NLRP3 inflammasome and itaconate related diseases.
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Affiliation(s)
- Xiaoyan Wu
- Guangdong Provincial Key Laboratory of New Drug Screening, School of Pharmaceutical Sciences, Southern Medical University, Guangzhou, China
| | - Xin Yi
- Guangdong Provincial Key Laboratory of New Drug Screening, School of Pharmaceutical Sciences, Southern Medical University, Guangzhou, China
| | - Boxin Zhao
- Department of Pharmacy, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Yuanxing Zhi
- Guangdong Provincial Key Laboratory of New Drug Screening, School of Pharmaceutical Sciences, Southern Medical University, Guangzhou, China
| | - Ziwei Xu
- Guangdong Provincial Key Laboratory of New Drug Screening, School of Pharmaceutical Sciences, Southern Medical University, Guangzhou, China
| | - Ying Cao
- Guangdong Provincial Key Laboratory of New Drug Screening, School of Pharmaceutical Sciences, Southern Medical University, Guangzhou, China
| | - Xiong Cao
- Key Laboratory of Mental Health of the Ministry of Education, Key Laboratory of Psychiatric Disorders of Guangdong Province, Department of Neurobiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Jianxin Pang
- Guangdong Provincial Key Laboratory of New Drug Screening, School of Pharmaceutical Sciences, Southern Medical University, Guangzhou, China
| | - Ken Kin Lam Yung
- Department of Science and Environmental Studies, the Education University of Hong Kong, Hong Kong, China
| | - Shiqing Zhang
- JNU-HKUST Joint Laboratory for Neuroscience and Innovative Drug Research, College of Pharmacy, Jinan University, Guangzhou, China.
| | - Shuwen Liu
- Guangdong Provincial Key Laboratory of New Drug Screening, School of Pharmaceutical Sciences, Southern Medical University, Guangzhou, China.
| | - Pingzheng Zhou
- Guangdong Provincial Key Laboratory of New Drug Screening, School of Pharmaceutical Sciences, Southern Medical University, Guangzhou, China.
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7
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Liu T, Li Y, Wang D, Stauber T, Zhao J. Trends in volume-regulated anion channel (VRAC) research: visualization and bibliometric analysis from 2014 to 2022. Front Pharmacol 2023; 14:1234885. [PMID: 37538172 PMCID: PMC10394876 DOI: 10.3389/fphar.2023.1234885] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Accepted: 07/10/2023] [Indexed: 08/05/2023] Open
Abstract
Objective: In this study, we utilized bibliometric methods to assess the worldwide scientific output and identify hotspots related to the research on the volume-regulated anion channel (VRAC) from 2014 to 2022. Methods: From Web of Science, we obtained studies related to VRAC published from 2014 to 2022. To analyzed the data, we utilized VOSviewer, a tool for visualizing network, to create networks based on the collaboration between countries, institutions, and authors. Additionally, we performed an analysis of journal co-citation, document citation, and co-occurrence of keywords. Furthermore, we employed CiteSpace (6.1. R6 Advanced) to analyzed keywords and co-cited references with the strongest burst. Results: The final analysis included a total of 278 related articles and reviews, covering the period from 2014 to 2022. The United States emerged as the leading country contributing to this field, while the University of Copenhagen stood out as the most prominent institution. The author with most publications and most citations was Thomas J. Jentsch. Among the cited references, the article by Voss et al. published in Science (2014) gained significant attention for its identification of LRRC8 heteromers as a crucial component of the volume-regulated anion channel VRAC. Pflügers Archiv European Journal of Physiology and Journal of Physiology-London were the leading journals in terms of the quantity of associated articles and citations. Through the analysis of keyword co-occurrence, it was discovered that VRAC is involved in various physiological processes including cell growth, migration, apoptosis, swelling, and myogenesis, as well as anion and organic osmolyte transport including chloride, taurine, glutamate and ATP. VRAC is also associated with related ion channels such as TMEM16A, TMEM16F, pannexin, and CFTR, and associated with various diseases including epilepsy, leukodystrophy, atherosclerosis, hypertension, cerebral edema, stroke, and different types of cancer including gastric cancer, glioblastoma and hepatocellular carcinoma. Furthermore, VRAC is involved in anti-tumor drug resistance by regulating the uptake of platinum-based drugs and temozolomide. Additionally, VRAC has been studied in the context of pharmacology involving DCPIB and flavonoids. Conclusion: The aim of this bibliometric analysis is to provide an overall perspective for research on VRAC. VRAC has become a topic of increasing interest, and our analysis shows that it continues to be a prominent area. This study offers insights into the investigation of VRAC channel and may guide researchers in identifying new directions for future research.
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Affiliation(s)
- Tianbao Liu
- Key Laboratory of Endocrine Glucose & Lipids Metabolism and Brain Aging, Ministry of Education, Department of Endocrinology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, Shandong, China
- Shandong Key Laboratory of Endocrinology and Lipid Metabolism, Jinan, Shandong, China
- Shandong Institute of Endocrine and Metabolic Disease, Jinan, Shandong, China
| | - Yin Li
- Department of Oncology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Shandong Provincial Hospital, Jinan, Shandong, China
| | - Dawei Wang
- Key Laboratory of Endocrine Glucose & Lipids Metabolism and Brain Aging, Ministry of Education, Department of Endocrinology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, Shandong, China
- Shandong Key Laboratory of Endocrinology and Lipid Metabolism, Jinan, Shandong, China
- Shandong Institute of Endocrine and Metabolic Disease, Jinan, Shandong, China
- Department of Endocrinology, Shandong Provincial Hospital, Shandong University, Jinan, Shandong, China
| | - Tobias Stauber
- Institute for Molecular Medicine, MSH Medical School Hamburg, Hamburg, Germany
| | - Jiajun Zhao
- Key Laboratory of Endocrine Glucose & Lipids Metabolism and Brain Aging, Ministry of Education, Department of Endocrinology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, Shandong, China
- Shandong Key Laboratory of Endocrinology and Lipid Metabolism, Jinan, Shandong, China
- Shandong Institute of Endocrine and Metabolic Disease, Jinan, Shandong, China
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Yan P, Ke B, Fang X. Ion channels as a therapeutic target for renal fibrosis. Front Physiol 2022; 13:1019028. [PMID: 36277193 PMCID: PMC9581181 DOI: 10.3389/fphys.2022.1019028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2022] [Accepted: 09/20/2022] [Indexed: 11/13/2022] Open
Abstract
Renal ion channel transport and electrolyte disturbances play an important role in the process of functional impairment and fibrosis in the kidney. It is well known that there are limited effective drugs for the treatment of renal fibrosis, and since a large number of ion channels are involved in the renal fibrosis process, understanding the mechanisms of ion channel transport and the complex network of signaling cascades between them is essential to identify potential therapeutic approaches to slow down renal fibrosis. This review summarizes the current work of ion channels in renal fibrosis. We pay close attention to the effect of cystic fibrosis transmembrane conductance regulator (CFTR), transmembrane Member 16A (TMEM16A) and other Cl− channel mediated signaling pathways and ion concentrations on fibrosis, as well as the various complex mechanisms for the action of Ca2+ handling channels including Ca2+-release-activated Ca2+ channel (CRAC), purinergic receptor, and transient receptor potential (TRP) channels. Furthermore, we also focus on the contribution of Na+ transport such as epithelial sodium channel (ENaC), Na+, K+-ATPase, Na+-H+ exchangers, and K+ channels like Ca2+-activated K+ channels, voltage-dependent K+ channel, ATP-sensitive K+ channels on renal fibrosis. Proposed potential therapeutic approaches through further dissection of these mechanisms may provide new therapeutic opportunities to reduce the burden of chronic kidney disease.
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Ghouli MR, Fiacco TA, Binder DK. Structure-function relationships of the LRRC8 subunits and subdomains of the volume-regulated anion channel (VRAC). Front Cell Neurosci 2022; 16:962714. [PMID: 36035259 PMCID: PMC9399500 DOI: 10.3389/fncel.2022.962714] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Accepted: 07/18/2022] [Indexed: 11/19/2022] Open
Abstract
Volume Regulated Anion Channels (VRAC) are critical contributors to cell volume homeostasis and are expressed ubiquitously in all vertebrate cells. VRAC sense increases in cell volume, and act to return cells to baseline volume in a process known as regulatory volume decrease (RVD) through the efflux of anions and organic osmolytes. This review will highlight seminal studies that elucidated the role of VRAC in RVD, their characteristics as a function of subunit specificity, and their clinical relevance in physiology and pathology. VRAC are also known as volume-sensitive outward rectifiers (VSOR) and volume-sensitive organic osmolyte/anion channels (VSOAC). In this review, the term VRAC will be used to refer to this family of channels.
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Affiliation(s)
- Manolia R. Ghouli
- Division of Biomedical Sciences, School of Medicine, University of California–Riverside, Riverside, CA, United States
| | - Todd A. Fiacco
- Department of Cell Biology and Neuroscience, Center for Glial-Neuronal Interactions, University of California–Riverside, Riverside, CA, United States
| | - Devin K. Binder
- Division of Biomedical Sciences, School of Medicine, University of California–Riverside, Riverside, CA, United States
- *Correspondence: Devin K. Binder
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López-Cayuqueo KI, Planells-Cases R, Pietzke M, Oliveras A, Kempa S, Bachmann S, Jentsch TJ. Renal Deletion of LRRC8/VRAC Channels Induces Proximal Tubulopathy. J Am Soc Nephrol 2022; 33:1528-1545. [PMID: 35777784 PMCID: PMC9342636 DOI: 10.1681/asn.2021111458] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Accepted: 05/13/2022] [Indexed: 01/25/2023] Open
Abstract
BACKGROUND Volume-regulated anion channels (VRACs) are heterohexamers of LRRC8A with LRRC8B, -C, -D, or -E in various combinations. Depending on the subunit composition, these swelling-activated channels conduct chloride, amino acids, organic osmolytes, and drugs. Despite VRACs' role in cell volume regulation, and large osmolarity changes in the kidney, neither the localization nor the function of VRACs in the kidney is known. METHODS Mice expressing epitope-tagged LRRC8 subunits were used to determine the renal localization of all VRAC subunits. Mice carrying constitutive deletions of Lrrc8b-e, or with inducible or cell-specific ablation of Lrrc8a, were analyzed to assess renal functions of VRACs. Analysis included histology, urine and serum parameters in different diuresis states, and metabolomics. RESULTS The kidney expresses all five VRAC subunits with strikingly distinct localization. Whereas LRRC8C is exclusively found in vascular endothelium, all other subunits are found in the nephron. LRRC8E is specific for intercalated cells, whereas LRRC8A, LRRC8B, and LRRC8D are prominent in basolateral membranes of proximal tubules. Conditional deletion of LRRC8A in proximal but not distal tubules and constitutive deletion of LRRC8D cause proximal tubular injury, increased diuresis, and mild Fanconi-like symptoms. CONCLUSIONS VRAC/LRRC8 channels are crucial for the function and integrity of proximal tubules, but not for more distal nephron segments despite their larger need for volume regulation. LRRC8A/D channels may be required for the basolateral exit of many organic compounds, including cellular metabolites, in proximal tubules. Proximal tubular injury likely results from combined accumulation of several transported molecules in the absence of VRAC channels.
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Affiliation(s)
- Karen I. López-Cayuqueo
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP) and Max-Delbrück-Centrum für Molekulare Medizin (MDC), Berlin, Germany
| | - Rosa Planells-Cases
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP) and Max-Delbrück-Centrum für Molekulare Medizin (MDC), Berlin, Germany
| | - Matthias Pietzke
- Integrative Metabolomics and Proteomics, Berlin Institute of Medical Systems Biology/Max-Delbrück-Centrum für Molekulare Medizin, Berlin, Germany
| | - Anna Oliveras
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP) and Max-Delbrück-Centrum für Molekulare Medizin (MDC), Berlin, Germany
| | - Stefan Kempa
- Integrative Metabolomics and Proteomics, Berlin Institute of Medical Systems Biology/Max-Delbrück-Centrum für Molekulare Medizin, Berlin, Germany
| | - Sebastian Bachmann
- Department of Anatomy, Charité Universitätsmedizin Berlin, Berlin, Germany
| | - Thomas J. Jentsch
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP) and Max-Delbrück-Centrum für Molekulare Medizin (MDC), Berlin, Germany,NeuroCure Centre of Excellence, Charité Universitätsmedizin Berlin, Berlin, Germany
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11
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Bertelli S, Zuccolini P, Gavazzo P, Pusch M. Molecular determinants underlying VRAC subunit dependent oxidation sensitivity. J Physiol 2022; 600:3965-3982. [PMID: 35861288 PMCID: PMC9540897 DOI: 10.1113/jp283321] [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: 05/12/2022] [Accepted: 07/15/2022] [Indexed: 11/12/2022] Open
Abstract
Abstract The volume‐regulated anion channel (VRAC) is formed by LRRC8 subunits. Besides their role in the maintenance of cell homeostasis, VRACs are critically involved in oxidative stress mechanisms: reactive oxygen species directly modulate VRACs in a subunit‐dependent manner. It was reported that LRRC8A–LRRC8E heteromeric channels are activated by oxidation, whereas LRRC8A–LRRC8C heteromers are inhibited. Here we adopted chimeric‐ as well as concatemeric‐based strategies to identify residues responsible for the divergent effect of oxidants. We identified two cysteines in the first two leucine rich repeats of LRRC8E, C424 and C448, as the targets of oxidation. Oxidation likely results in the formation of a disulfide bond between the two cysteines, which in turn induces a conformational change leading to channel activation. Additionally, we found that LRRC8C inhibition is caused by oxidation of the first methionine. We thus identified crucial molecular elements involved in channel activation, which are conceivably relevant in determining physiological ROS effects.
![]() Key points Volume‐regulated anion channels (VRACs) are heterohexameric complexes composed of an essential LRRC8A subunit and a variable number of LRRC8B–E subunits. VRACs are directly regulated by oxidation, with LRRC8A–LRRC8E heteromers being potentiated and LRRC8A–LRRC8C heteromers being inhibited by oxidation. We identified two LRRC8E specific intracellular cysteines that form a disulfide bond upon oxidation leading to LRRC8A–LRRC8E potentiation. Inhibition of LRRC8A–LRRC8C heteromers is mediated by the oxidation of the start methionine, being additionally dependent on the identity of the LRR domain. Besides providing physiological insights concerning the outcome of reactive oxygen species modulation, the results point to key structural elements involved in VRAC activation.
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Affiliation(s)
- Sara Bertelli
- Istituto di Biofisica, Consiglio Nazionale delle Ricerche, Genova, Italy.,Scuola Internazionale Superiore di Studi Avanzati (SISSA), Trieste, Italy
| | - Paolo Zuccolini
- Istituto di Biofisica, Consiglio Nazionale delle Ricerche, Genova, Italy
| | - Paola Gavazzo
- Istituto di Biofisica, Consiglio Nazionale delle Ricerche, Genova, Italy
| | - Michael Pusch
- Istituto di Biofisica, Consiglio Nazionale delle Ricerche, Genova, Italy
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12
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Harcha PA, López-López T, Palacios AG, Sáez PJ. Pannexin Channel Regulation of Cell Migration: Focus on Immune Cells. Front Immunol 2022; 12:750480. [PMID: 34975840 PMCID: PMC8716617 DOI: 10.3389/fimmu.2021.750480] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Accepted: 11/15/2021] [Indexed: 12/12/2022] Open
Abstract
The role of Pannexin (PANX) channels during collective and single cell migration is increasingly recognized. Amongst many functions that are relevant to cell migration, here we focus on the role of PANX-mediated adenine nucleotide release and associated autocrine and paracrine signaling. We also summarize the contribution of PANXs with the cytoskeleton, which is also key regulator of cell migration. PANXs, as mechanosensitive ATP releasing channels, provide a unique link between cell migration and purinergic communication. The functional association with several purinergic receptors, together with a plethora of signals that modulate their opening, allows PANX channels to integrate physical and chemical cues during inflammation. Ubiquitously expressed in almost all immune cells, PANX1 opening has been reported in different immunological contexts. Immune activation is the epitome coordination between cell communication and migration, as leukocytes (i.e., T cells, dendritic cells) exchange information while migrating towards the injury site. In the current review, we summarized the contribution of PANX channels during immune cell migration and recruitment; although we also compile the available evidence for non-immune cells (including fibroblasts, keratinocytes, astrocytes, and cancer cells). Finally, we discuss the current evidence of PANX1 and PANX3 channels as a both positive and/or negative regulator in different inflammatory conditions, proposing a general mechanism of these channels contribution during cell migration.
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Affiliation(s)
- Paloma A Harcha
- Centro Interdisciplinario de Neurociencia de Valparaíso, Instituto de Neurociencia, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Tamara López-López
- Cell Communication and Migration Laboratory, Institute of Biochemistry and Molecular Cell Biology, Center for Experimental Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Adrián G Palacios
- Centro Interdisciplinario de Neurociencia de Valparaíso, Instituto de Neurociencia, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Pablo J Sáez
- Cell Communication and Migration Laboratory, Institute of Biochemistry and Molecular Cell Biology, Center for Experimental Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
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13
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Okada Y, Sabirov RZ, Merzlyak PG, Numata T, Sato-Numata K. Properties, Structures, and Physiological Roles of Three Types of Anion Channels Molecularly Identified in the 2010's. Front Physiol 2022; 12:805148. [PMID: 35002778 PMCID: PMC8733619 DOI: 10.3389/fphys.2021.805148] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Accepted: 12/06/2021] [Indexed: 11/24/2022] Open
Abstract
Molecular identification was, at last, successfully accomplished for three types of anion channels that are all implicated in cell volume regulation/dysregulation. LRRC8A plus LRRC8C/D/E, SLCO2A1, and TMEM206 were shown to be the core or pore-forming molecules of the volume-sensitive outwardly rectifying anion channel (VSOR) also called the volume-regulated anion channel (VRAC), the large-conductance maxi-anion channel (Maxi-Cl), and the acid-sensitive outwardly rectifying anion channel (ASOR) also called the proton-activated anion channel (PAC) in 2014, 2017, and 2019, respectively. More recently in 2020 and 2021, we have identified the S100A10-annexin A2 complex and TRPM7 as the regulatory proteins for Maxi-Cl and VSOR/VRAC, respectively. In this review article, we summarize their biophysical and structural properties as well as their physiological roles by comparing with each other on the basis of their molecular insights. We also point out unsolved important issues to be elucidated soon in the future.
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Affiliation(s)
- Yasunobu Okada
- National Institute for Physiological Sciences (NIPS), Okazaki, Japan.,Department of Physiology, School of Medicine, Aichi Medical University, Nagakute, Japan.,Department of Physiology, Kyoto Prefectural University of Medicine, Kyoto, Japan.,Cardiovascular Research Institute, Yokohama City University, Yokohama, Japan
| | - Ravshan Z Sabirov
- Laboratory of Molecular Physiology, Institute of Biophysics and Biochemistry, National University of Uzbekistan, Tashkent, Uzbekistan
| | - Petr G Merzlyak
- Laboratory of Molecular Physiology, Institute of Biophysics and Biochemistry, National University of Uzbekistan, Tashkent, Uzbekistan
| | - Tomohiro Numata
- Department of Integrative Physiology, Graduate School of Medicine, Akita University, Akita, Japan
| | - Kaori Sato-Numata
- Department of Integrative Physiology, Graduate School of Medicine, Akita University, Akita, Japan.,Japan Society for the Promotion of Science, Tokyo, Japan
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14
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Li T, Li X, Mao R, Pan L, Que Y, Zhu C, Jin L, Li S. NLRP2 inhibits cell proliferation and migration by regulating EMT in lung adenocarcinoma cells. Cell Biol Int 2021; 46:588-598. [PMID: 34957627 DOI: 10.1002/cbin.11755] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Revised: 12/20/2021] [Accepted: 12/22/2021] [Indexed: 12/14/2022]
Abstract
Nucleotide-binding oligomerization domain-like receptors (NLRs) are crucial types of innate immune sensors and well known for their critical roles in the immune system. However, how NLRP2 functions in the progression of cancer is largely unknown. Here, we identified NLRP2 as an antioncogene in lung adenocarcinoma (LUAD) cells. Gain- and loss-of-function studies revealed that NLRP2 silencing promoted cell proliferation and migration by stimulating NF-kB signaling in the microenvironment, which induced epithelial-to-mesenchymal transition (EMT) phenotype and cytoskeleton reorganization in LUAD cells. The addition of the NF-kB inhibitor rescued the function of NLRP2 on EMT. Moreover, NLRP2 increased the level of cofilin phosphorylation and repressed subsequent F-actin reorganization. Consistently, the in vivo study showed that NLRP2 played an inhibitory role in forming metastasis foci. Taken together, NLRP2 inhibited cell proliferation and migration by regulating EMT in LUAD cells, demonstrating the essential function of NLRP2 in the development of LUAD.
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Affiliation(s)
- Tiantian Li
- Department of Pharmacology, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Xu Li
- Department of Pharmacology, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Rongchen Mao
- Department of Pharmacology, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Lihua Pan
- Department of Pharmacology, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Yuhui Que
- Department of Pharmacology, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Chao Zhu
- Department of Pharmacology, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Lai Jin
- Department of Pharmacology, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Shengnan Li
- Department of Pharmacology, Nanjing Medical University, Nanjing, Jiangsu, China
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15
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Melis N, Carcy R, Rubera I, Cougnon M, Duranton C, Tauc M, Pisani DF. Akt Inhibition as Preconditioning Treatment to Protect Kidney Cells against Anoxia. Int J Mol Sci 2021; 23:ijms23010152. [PMID: 35008578 PMCID: PMC8745656 DOI: 10.3390/ijms23010152] [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: 10/18/2021] [Revised: 11/15/2021] [Accepted: 12/21/2021] [Indexed: 11/16/2022] Open
Abstract
Lesions issued from the ischemia/reperfusion (I/R) stress are a major challenge in human pathophysiology. Of human organs, the kidney is highly sensitive to I/R because of its high oxygen demand and poor regenerative capacity. Previous studies have shown that targeting the hypusination pathway of eIF5A through GC7 greatly improves ischemic tolerance and can be applied successfully to kidney transplants. The protection process correlates with a metabolic shift from oxidative phosphorylation to glycolysis. Because the protein kinase B Akt is involved in ischemic protective mechanisms and glucose metabolism, we looked for a link between the effects of GC7 and Akt in proximal kidney cells exposed to anoxia or the mitotoxic myxothiazol. We found that GC7 treatment resulted in impaired Akt phosphorylation at the Ser473 and Thr308 sites, so the effects of direct Akt inhibition as a preconditioning protocol on ischemic tolerance were investigated. We evidenced that Akt inhibitors provide huge protection for kidney cells against ischemia and myxothiazol. The pro-survival effect of Akt inhibitors, which is reversible, implied a decrease in mitochondrial ROS production but was not related to metabolic changes or an antioxidant defense increase. Therefore, the inhibition of Akt can be considered as a preconditioning treatment against ischemia.
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Affiliation(s)
- Nicolas Melis
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892, USA;
| | - Romain Carcy
- Université Côte d’Azur, CNRS, LP2M, 06103 Nice, France; (R.C.); (I.R.); (M.C.); (C.D.); (M.T.)
- CHU Nice, Hôpital Pasteur 2, Service de Réanimation Polyvalente et Service de Réanimation des Urgences Vitales, 06103 Nice, France
- Laboratories of Excellence Ion Channel Science and Therapeutics, 06103 Nice, France
| | - Isabelle Rubera
- Université Côte d’Azur, CNRS, LP2M, 06103 Nice, France; (R.C.); (I.R.); (M.C.); (C.D.); (M.T.)
- Laboratories of Excellence Ion Channel Science and Therapeutics, 06103 Nice, France
| | - Marc Cougnon
- Université Côte d’Azur, CNRS, LP2M, 06103 Nice, France; (R.C.); (I.R.); (M.C.); (C.D.); (M.T.)
- Laboratories of Excellence Ion Channel Science and Therapeutics, 06103 Nice, France
| | - Christophe Duranton
- Université Côte d’Azur, CNRS, LP2M, 06103 Nice, France; (R.C.); (I.R.); (M.C.); (C.D.); (M.T.)
- Laboratories of Excellence Ion Channel Science and Therapeutics, 06103 Nice, France
| | - Michel Tauc
- Université Côte d’Azur, CNRS, LP2M, 06103 Nice, France; (R.C.); (I.R.); (M.C.); (C.D.); (M.T.)
- Laboratories of Excellence Ion Channel Science and Therapeutics, 06103 Nice, France
| | - Didier F. Pisani
- Université Côte d’Azur, CNRS, LP2M, 06103 Nice, France; (R.C.); (I.R.); (M.C.); (C.D.); (M.T.)
- Laboratories of Excellence Ion Channel Science and Therapeutics, 06103 Nice, France
- Correspondence:
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16
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Kolobkova Y, Pervaiz S, Stauber T. The expanding toolbox to study the LRRC8-formed volume-regulated anion channel VRAC. CURRENT TOPICS IN MEMBRANES 2021; 88:119-163. [PMID: 34862024 DOI: 10.1016/bs.ctm.2021.10.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
The volume-regulated anion channel (VRAC) is activated upon cell swelling and facilitates the passive movement of anions across the plasma membrane in cells. VRAC function underlies many critical homeostatic processes in vertebrate cells. Among them are the regulation of cell volume and membrane potential, glutamate release and apoptosis. VRAC is also permeable for organic osmolytes and metabolites including some anti-cancer drugs and antibiotics. Therefore, a fundamental understanding of VRAC's structure-function relationships, its physiological roles, its utility for therapy of diseases, and the development of compounds modulating its activity are important research frontiers. Here, we describe approaches that have been applied to study VRAC since it was first described more than 30 years ago, providing an overview of the recent methodological progress. The diverse applications reflecting a compromise between the physiological situation, biochemical definition, and biophysical resolution range from the study of VRAC activity using a classic electrophysiology approach, to the measurement of osmolytes transport by various means and the investigation of its activation using a novel biophysical approach based on fluorescence resonance energy transfer.
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Affiliation(s)
- Yulia Kolobkova
- Department of Human Medicine and Institute for Molecular Medicine, MSH Medical School Hamburg, Germany
| | - Sumaira Pervaiz
- Institute of Chemistry and Biochemistry, Freie Universität Berlin, Germany
| | - Tobias Stauber
- Department of Human Medicine and Institute for Molecular Medicine, MSH Medical School Hamburg, Germany; Institute of Chemistry and Biochemistry, Freie Universität Berlin, Germany.
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17
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Monitoring of compound resting membrane potentials of cell cultures with ratiometric genetically encoded voltage indicators. Commun Biol 2021; 4:1164. [PMID: 34620975 PMCID: PMC8497494 DOI: 10.1038/s42003-021-02675-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Accepted: 09/13/2021] [Indexed: 11/29/2022] Open
Abstract
The cellular resting membrane potential (Vm) not only determines electrical responsiveness of excitable cells but also plays pivotal roles in non-excitable cells, mediating membrane transport, cell-cycle progression, and tumorigenesis. Studying these processes requires estimation of Vm, ideally over long periods of time. Here, we introduce two ratiometric genetically encoded Vm indicators, rArc and rASAP, and imaging and analysis procedures for measuring differences in average resting Vm between cell groups. We investigated the influence of ectopic expression of K+ channels and their disease-causing mutations involved in Andersen-Tawil (Kir2.1) and Temple-Baraitser (KV10.1) syndrome on median resting Vm of HEK293T cells. Real-time long-term monitoring of Vm changes allowed to estimate a 40–50 min latency from induction of transcription to functional Kir2.1 channels in HEK293T cells. The presented methodology is readily implemented with standard fluorescence microscopes and offers deeper insights into the role of the resting Vm in health and disease. Rühl et al. report the generation of ratiometric genetically encoded voltage indicators (GEVIs) and establish that they can be used in high-throughput automated imaging to measure compound membrane potential (Vm) in mammalian cells. This method is implementable with standard fluorescence microscopes and has the potential to offer insights into the role of the resting Vm in health and disease.
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18
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Siemer S, Fauth T, Scholz P, Al-Zamel Y, Khamis A, Gül D, Freudelsperger L, Wollenberg B, Becker S, Stauber RH, Hagemann J. Profiling Cisplatin Resistance in Head and Neck Cancer: A Critical Role of the VRAC Ion Channel for Chemoresistance. Cancers (Basel) 2021; 13:4831. [PMID: 34638315 PMCID: PMC8508519 DOI: 10.3390/cancers13194831] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Revised: 09/23/2021] [Accepted: 09/24/2021] [Indexed: 12/11/2022] Open
Abstract
Treatment success of head and neck cancers (HNSCC) is often hindered by tumor relapses due to therapy resistances. This study aimed at profiling cisplatin resistance mechanisms and identifying biomarkers potentially suitable as drug targets and for patient stratification. Bioinformatic analyses of suggested resistance factors in a cohort of 565 HNSCC patients identified the VRAC ion channel as a clinically relevant indicator for recurrent diseases following radiochemotherapy (p = 0.042). Other drug import/export transporters, such as CTR1, OCT1, or MRP1, were found to be less relevant. To experimentally verify VRAC's critical role for cisplatin resistance, we used CRISPR/Cas9 knockout resulting in cisplatin-resistant HNSCC cells, which could be resensitized by VRAC expression. Next-generation sequencing further underlined VRAC's importance and identified VRAC-regulated signaling networks, potentially also contributing to cisplatin resistance. CTR1, OCT1, or MRP1 did not contribute to increased cisplatin resistance. In addition to two-dimensional HNSCC models, three-dimensional tumor spheroid cultures confirmed VRAC's unique role for cisplatin sensitivity. Here, resistance correlated with DNA damage and downstream apoptosis. The cisplatin specificity of the identified VRAC pathway was verified by testing paclitaxel and doxorubicin. Our results were independently confirmed in naturally occurring, cisplatin-resistant HNSCC cancer cell models. Collectively, we here demonstrate VRAC's role for cisplatin resistance in HNSCC and its relevance as a potential drug target and/or prognostic biomarker for chemotherapy resistance.
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Affiliation(s)
- Svenja Siemer
- Department of Otorhinolaryngology Head and Neck Surgery, Molecular and Cellular Oncology, University Medical Center, 55131 Mainz, Germany; (S.S.); (Y.A.-Z.); (A.K.); (D.G.); (L.F.); (S.B.); (J.H.)
| | - Torsten Fauth
- BRAIN Biotech AG, 64673 Zwingenberg, Germany; (T.F.); (P.S.)
| | - Paul Scholz
- BRAIN Biotech AG, 64673 Zwingenberg, Germany; (T.F.); (P.S.)
| | - Yara Al-Zamel
- Department of Otorhinolaryngology Head and Neck Surgery, Molecular and Cellular Oncology, University Medical Center, 55131 Mainz, Germany; (S.S.); (Y.A.-Z.); (A.K.); (D.G.); (L.F.); (S.B.); (J.H.)
| | - Aya Khamis
- Department of Otorhinolaryngology Head and Neck Surgery, Molecular and Cellular Oncology, University Medical Center, 55131 Mainz, Germany; (S.S.); (Y.A.-Z.); (A.K.); (D.G.); (L.F.); (S.B.); (J.H.)
| | - Désirée Gül
- Department of Otorhinolaryngology Head and Neck Surgery, Molecular and Cellular Oncology, University Medical Center, 55131 Mainz, Germany; (S.S.); (Y.A.-Z.); (A.K.); (D.G.); (L.F.); (S.B.); (J.H.)
| | - Laura Freudelsperger
- Department of Otorhinolaryngology Head and Neck Surgery, Molecular and Cellular Oncology, University Medical Center, 55131 Mainz, Germany; (S.S.); (Y.A.-Z.); (A.K.); (D.G.); (L.F.); (S.B.); (J.H.)
| | - Barbara Wollenberg
- Department of Otorhinolaryngology Head and Neck Surgery, University Hospital Klinikum Rechts der Isar, 81675 Munich, Germany;
| | - Sven Becker
- Department of Otorhinolaryngology Head and Neck Surgery, Molecular and Cellular Oncology, University Medical Center, 55131 Mainz, Germany; (S.S.); (Y.A.-Z.); (A.K.); (D.G.); (L.F.); (S.B.); (J.H.)
- Department of Otorhinolaryngology, University Medical Center Tuebingen, 72076 Tuebingen, Germany
| | - Roland H. Stauber
- Department of Otorhinolaryngology Head and Neck Surgery, Molecular and Cellular Oncology, University Medical Center, 55131 Mainz, Germany; (S.S.); (Y.A.-Z.); (A.K.); (D.G.); (L.F.); (S.B.); (J.H.)
| | - Jan Hagemann
- Department of Otorhinolaryngology Head and Neck Surgery, Molecular and Cellular Oncology, University Medical Center, 55131 Mainz, Germany; (S.S.); (Y.A.-Z.); (A.K.); (D.G.); (L.F.); (S.B.); (J.H.)
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19
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Choi H, Rohrbough JC, Nguyen HN, Dikalova A, Lamb FS. Oxidant-resistant LRRC8A/C anion channels support superoxide production by NADPH oxidase 1. J Physiol 2021; 599:3013-3036. [PMID: 33932953 DOI: 10.1113/jp281577] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Accepted: 04/23/2021] [Indexed: 12/20/2022] Open
Abstract
KEY POINTS LRRC8A-containing anion channels associate with NADPH oxidase 1 (Nox1) and regulate superoxide production and tumour necrosis factor-α (TNFα) signalling. Here we show that LRRC8C and 8D also co-immunoprecipitate with Nox1 in vascular smooth muscle cells. LRRC8C knockdown inhibited TNFα-induced O2 •- production, receptor endocytosis, nuclear factor-κB (NF-κB) activation and proliferation while LRRC8D knockdown enhanced NF-κB activation. Significant changes in LRRC8 isoform expression in human atherosclerosis and psoriasis suggest compensation for increased inflammation. The oxidant chloramine-T (ChlorT, 1 mM) weakly (∼25%) inhibited LRRC8C currents but potently (∼80%) inhibited LRRC8D currents. Substitution of the extracellular loop (EL1, EL2) domains of 8D into 8C conferred significantly stronger (69%) ChlorT-dependent inhibition. ChlorT exposure impaired subsequent current block by DCPIB, which occurs through interaction with EL1, further implicating external oxidation sites. LRRC8A/C channels most effectively sustain Nox1 activity at the plasma membrane. This may result from their ability to remain active in an oxidized microenvironment. ABSTRACT Tumour necrosis factor-α (TNFα) activates NADPH oxidase 1 (Nox1) in vascular smooth muscle cells (VSMCs), producing superoxide (O2 •- ) required for subsequent signalling. LRRC8 family proteins A-E comprise volume-regulated anion channels (VRACs). The required subunit LRRC8A physically associates with Nox1, and VRAC activity is required for Nox activity and the inflammatory response to TNFα. VRAC currents are modulated by oxidants, suggesting that channel oxidant sensitivity and proximity to Nox1 may play a physiologically relevant role. In VSMCs, LRRC8C knockdown (siRNA) recapitulated the effects of siLRRC8A, inhibiting TNFα-induced extracellular and endosomal O2 •- production, receptor endocytosis, nuclear factor-κB (NF-κB) activation and proliferation. In contrast, siLRRC8D potentiated NF-κB activation. Nox1 co-immunoprecipitated with 8C and 8D, and colocalized with 8D at the plasma membrane and in vesicles. We compared VRAC currents mediated by homomeric and heteromeric LRRC8C and LRRC8D channels expressed in HEK293 cells. The oxidant chloramine T (ChlorT, 1 mM) weakly inhibited 8C, but potently inhibited 8D currents. ChlorT exposure also impaired subsequent current block by the VRAC blocker DCPIB, implicating external sites of oxidation. Substitution of the 8D extracellular loop domains (EL1, EL2) into 8C conferred significantly stronger ChlorT-mediated inhibition of 8C currents. Our results suggest that LRRC8A/C channel activity can be effectively maintained in the oxidized microenvironment expected to result from Nox1 activation at the plasma membrane. Increased ratios of 8D:8C expression may potentially depress inflammatory responses to TNFα. LRRC8A/C channel downregulation represents a novel strategy to reduce TNFα-induced inflammation.
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Affiliation(s)
- Hyehun Choi
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN, 37232, USA
| | - Jeffrey C Rohrbough
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN, 37232, USA
| | - Hong N Nguyen
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN, 37232, USA
| | - Anna Dikalova
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, 37232, USA
| | - Fred S Lamb
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN, 37232, USA
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20
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Chen X, Wang L, Cao L, Li T, Li Z, Sun Y, Ding J, Zhou C, Xie Y, Yue N, Nan J, Jia XM, Peng C, Li H, Yang J, Xiao H. Regulation of Anion Channel LRRC8 Volume-Regulated Anion Channels in Transport of 2'3'-Cyclic GMP-AMP and Cisplatin under Steady State and Inflammation. THE JOURNAL OF IMMUNOLOGY 2021; 206:2061-2074. [PMID: 33827893 DOI: 10.4049/jimmunol.2000989] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Accepted: 02/18/2021] [Indexed: 11/19/2022]
Abstract
The recently identified anion channel LRRC8 volume-regulated anion channels (VRACs) are heteromeric hexamers constituted with the obligate LRRC8A subunit paired with at least one of the accessory LRRC8B to LRRC8E subunits. In addition to transport chloride, taurine, and glutamate, LRRC8 VRACs also transport the anticancer agent cisplatin and STING agonists 2'3'-cyclic GMP-AMP (cGAMP) and cyclic dinucleotides; hence, they are implicated in a variety of physiological and pathological processes, such as cell swelling, stroke, cancer, and viral infection. Although the subunit composition largely determines VRAC substrate specificity, the opening of various VRAC pores under physiological and pathological settings remains enigmatic. In this study, we demonstrated that VRACs comprising LRRC8A and LRRC8E (LRRC8A/E-containing VRACs), specialized in cGAMP transport, can be opened by a protein component present in serum under resting condition. Serum depletion ablated the tonic activity of LRRC8A/E-containing VRACs, decreasing cGAMP transport in various human and murine cells. Also, heating or proteinase K treatment abolished the ability of serum to activate VRAC. Genetic analyses revealed a crucial role for cGAMP synthase (cGAS) in serum/TNF-promoted VRAC activation. Notably, the presence of cGAS on the plasma membrane, rather than its DNA-binding or enzymatic activity, enabled VRAC activation. Moreover, phospholipid PIP2 seemed to be instrumental in the membrane localization of cGAS and its association with VRACs. Corroborating a role for LRRC8A/D-containing VRACs in cisplatin transport, serum and TNF markedly potentiated cisplatin uptake and killing of cancer cells derived from human or mouse. Together, these observations provide new insights into the complex regulation of VRAC activation and suggest a novel approach to enhance the efficacy of cGAMP and cisplatin in treating infection and cancer.
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Affiliation(s)
- Xia Chen
- Institute of Cancer Biology and Drug Screening, College of Life Sciences, Lanzhou University, Lanzhou, Gansu, China.,The Center for Microbes, Development and Health, Chinese Academy of Sciences Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, Chinese Academy of Sciences Center for Excellence in Molecular Cell Science, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Li Wang
- The Center for Microbes, Development and Health, Chinese Academy of Sciences Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, Chinese Academy of Sciences Center for Excellence in Molecular Cell Science, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China.,Clinical Translational Research Center, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, China
| | - Limin Cao
- The Center for Microbes, Development and Health, Chinese Academy of Sciences Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, Chinese Academy of Sciences Center for Excellence in Molecular Cell Science, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Tiantian Li
- The Center for Microbes, Development and Health, Chinese Academy of Sciences Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, Chinese Academy of Sciences Center for Excellence in Molecular Cell Science, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Zhihong Li
- Zhangjiang Lab, National Facility for Protein Science in Shanghai, Shanghai, China.,Shanghai Science Research Center, Chinese Academy of Sciences, Shanghai, China
| | - Yumeng Sun
- The Center for Microbes, Development and Health, Chinese Academy of Sciences Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, Chinese Academy of Sciences Center for Excellence in Molecular Cell Science, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Jinqiu Ding
- The Center for Microbes, Development and Health, Chinese Academy of Sciences Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, Chinese Academy of Sciences Center for Excellence in Molecular Cell Science, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Chun Zhou
- Center for Allergic and Inflammatory Diseases and Department of Otolaryngology, Head and Neck Surgery, Affiliated Eye, Ear, Nose and Throat Hospital, Fudan University, Shanghai, China; and
| | - Yadong Xie
- The Center for Microbes, Development and Health, Chinese Academy of Sciences Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, Chinese Academy of Sciences Center for Excellence in Molecular Cell Science, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China.,Center for Allergic and Inflammatory Diseases and Department of Otolaryngology, Head and Neck Surgery, Affiliated Eye, Ear, Nose and Throat Hospital, Fudan University, Shanghai, China; and
| | - Nan Yue
- The Center for Microbes, Development and Health, Chinese Academy of Sciences Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, Chinese Academy of Sciences Center for Excellence in Molecular Cell Science, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Jing Nan
- Institute of Cancer Biology and Drug Screening, College of Life Sciences, Lanzhou University, Lanzhou, Gansu, China
| | - Xin-Ming Jia
- Clinical Translational Research Center, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, China
| | - Chao Peng
- Zhangjiang Lab, National Facility for Protein Science in Shanghai, Shanghai, China.,Shanghai Science Research Center, Chinese Academy of Sciences, Shanghai, China
| | - Huabin Li
- Center for Allergic and Inflammatory Diseases and Department of Otolaryngology, Head and Neck Surgery, Affiliated Eye, Ear, Nose and Throat Hospital, Fudan University, Shanghai, China; and
| | - Jinbo Yang
- Institute of Cancer Biology and Drug Screening, College of Life Sciences, Lanzhou University, Lanzhou, Gansu, China; .,Key Laboratory of Marine Drugs, Chinese Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, Qingdao, Shandong, China
| | - Hui Xiao
- The Center for Microbes, Development and Health, Chinese Academy of Sciences Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, Chinese Academy of Sciences Center for Excellence in Molecular Cell Science, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China;
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Okada Y, Sabirov RZ, Sato-Numata K, Numata T. Cell Death Induction and Protection by Activation of Ubiquitously Expressed Anion/Cation Channels. Part 1: Roles of VSOR/VRAC in Cell Volume Regulation, Release of Double-Edged Signals and Apoptotic/Necrotic Cell Death. Front Cell Dev Biol 2021; 8:614040. [PMID: 33511120 PMCID: PMC7835517 DOI: 10.3389/fcell.2020.614040] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Accepted: 12/15/2020] [Indexed: 12/18/2022] Open
Abstract
Cell volume regulation (CVR) is essential for survival and functions of animal cells. Actually, normotonic cell shrinkage and swelling are coupled to apoptotic and necrotic cell death and thus called the apoptotic volume decrease (AVD) and the necrotic volume increase (NVI), respectively. A number of ubiquitously expressed anion and cation channels are involved not only in CVD but also in cell death induction. This series of review articles address the question how cell death is induced or protected with using ubiquitously expressed ion channels such as swelling-activated anion channels, acid-activated anion channels and several types of TRP cation channels including TRPM2 and TRPM7. The Part 1 focuses on the roles of the volume-sensitive outwardly rectifying anion channels (VSOR), also called the volume-regulated anion channel (VRAC), which is activated by cell swelling or reactive oxygen species (ROS) in a manner dependent on intracellular ATP. First we describe phenotypical properties, the molecular identity, and physical pore dimensions of VSOR/VRAC. Second, we highlight the roles of VSOR/VRAC in the release of organic signaling molecules, such as glutamate, glutathione, ATP and cGAMP, that play roles as double-edged swords in cell survival. Third, we discuss how VSOR/VRAC is involved in CVR and cell volume dysregulation as well as in the induction of or protection from apoptosis, necrosis and regulated necrosis under pathophysiological conditions.
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Affiliation(s)
- Yasunobu Okada
- National Institute for Physiological Sciences, Okazaki, Japan
- Department of Physiology, School of Medicine, Aichi Medical University, Nagakute, Japan
- Department of Physiology, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Ravshan Z. Sabirov
- Laboratory of Molecular Physiology, Institute of Biophysics and Biochemistry, National University of Uzbekistan, Tashkent, Uzbekistan
| | - Kaori Sato-Numata
- Japan Society for the Promotion of Science, Tokyo, Japan
- Department of Physiology, School of Medicine, Fukuoka University, Fukuoka, Japan
| | - Tomohiro Numata
- Department of Physiology, School of Medicine, Fukuoka University, Fukuoka, Japan
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22
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Volume-regulated anion channel as a novel cancer therapeutic target. Int J Biol Macromol 2020; 159:570-576. [DOI: 10.1016/j.ijbiomac.2020.05.137] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Revised: 04/23/2020] [Accepted: 05/17/2020] [Indexed: 01/01/2023]
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