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Zhou M, Hanschmann EM, Römer A, Linn T, Petry SF. The significance of glutaredoxins for diabetes mellitus and its complications. Redox Biol 2024; 71:103043. [PMID: 38377787 PMCID: PMC10891345 DOI: 10.1016/j.redox.2024.103043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2023] [Accepted: 01/13/2024] [Indexed: 02/22/2024] Open
Abstract
Diabetes mellitus is a non-communicable metabolic disease hallmarked by chronic hyperglycemia caused by beta-cell failure. Diabetic complications affect the vasculature and result in macro- and microangiopathies, which account for a significantly increased morbidity and mortality. The rising incidence and prevalence of diabetes is a major global health burden. There are no feasible strategies for beta-cell preservation available in daily clinical practice. Therefore, patients rely on antidiabetic drugs or the application of exogenous insulin. Glutaredoxins (Grxs) are ubiquitously expressed and highly conserved members of the thioredoxin family of proteins. They have specific functions in redox-mediated signal transduction, iron homeostasis and biosynthesis of iron-sulfur (FeS) proteins, and the regulation of cell proliferation, survival, and function. The involvement of Grxs in chronic diseases has been a topic of research for several decades, suggesting them as therapeutic targets. Little is known about their role in diabetes and its complications. Therefore, this review summarizes the available literature on the significance of Grxs in diabetes and its complications. In conclusion, Grxs are differentially expressed in the endocrine pancreas and in tissues affected by diabetic complications, such as the heart, the kidneys, the eye, and the vasculature. They are involved in several pathways essential for insulin signaling, metabolic inflammation, glucose and fatty acid uptake and processing, cell survival, and iron and mitochondrial metabolism. Most studies describe significant changes in glutaredoxin expression and/or activity in response to the diabetic metabolism. In general, mitigated levels of Grxs are associated with oxidative distress, cell damage, and even cell death. The induced overexpression is considered a potential part of the cellular stress-response, counteracting oxidative distress and exerting beneficial impact on cell function such as insulin secretion, cytokine expression, and enzyme activity.
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Affiliation(s)
- Mengmeng Zhou
- Clinical Research Unit, Medical Clinic and Polyclinic III, Center of Internal Medicine, Justus Liebig University, Giessen, Germany
| | - Eva-Maria Hanschmann
- Experimental and Translational Research, Department of Otorhinolaryngology, University Hospital Essen, Essen, Germany
| | - Axel Römer
- Clinical Research Unit, Medical Clinic and Polyclinic III, Center of Internal Medicine, Justus Liebig University, Giessen, Germany
| | - Thomas Linn
- Clinical Research Unit, Medical Clinic and Polyclinic III, Center of Internal Medicine, Justus Liebig University, Giessen, Germany
| | - Sebastian Friedrich Petry
- Clinical Research Unit, Medical Clinic and Polyclinic III, Center of Internal Medicine, Justus Liebig University, Giessen, Germany.
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2
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Spontarelli K, Young VC, Sweazey R, Padro A, Lee J, Bueso T, Hernandez RM, Kim J, Katz A, Rossignol F, Turner C, Wilczewski CM, Maxwell GL, Holmgren M, Bailoo JD, Yano ST, Artigas P. ATP1A1-linked diseases require a malfunctioning protein product from one allele. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2024; 1871:119572. [PMID: 37659504 DOI: 10.1016/j.bbamcr.2023.119572] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 07/06/2023] [Accepted: 08/22/2023] [Indexed: 09/04/2023]
Abstract
Heterozygous germline variants in ATP1A1, the gene encoding the α1 subunit of the Na+/K+-ATPase (NKA), have been linked to diseases including primary hyperaldosteronism and the peripheral neuropathy Charcot-Marie-Tooth disease (CMT). ATP1A1 variants that cause CMT induce loss-of-function of NKA. This heterodimeric (αβ) enzyme hydrolyzes ATP to establish transmembrane electrochemical gradients of Na+ and K+ that are essential for electrical signaling and cell survival. Of the 4 catalytic subunit isoforms, α1 is ubiquitously expressed and is the predominant paralog in peripheral axons. Human population sequencing datasets indicate strong negative selection against both missense and protein-null ATP1A1 variants. To test whether haploinsufficiency generated by heterozygous protein-null alleles are sufficient to cause disease, we tested the neuromuscular characteristics of heterozygous Atp1a1+/- knockout mice and their wildtype littermates, while also evaluating if exercise increased CMT penetrance. We found that Atp1a1+/- mice were phenotypically normal up to 18 months of age. Consistent with the observations in mice, we report clinical phenotyping of a healthy adult human who lacks any clinical features of known ATP1A1-related diseases despite carrying a plasma-membrane protein-null early truncation variant, p.Y148*. Taken together, these results suggest that a malfunctioning gene product is required for disease induction by ATP1A1 variants and that if any pathology is associated with protein-null variants, they may display low penetrance or high age of onset.
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Affiliation(s)
- Kerri Spontarelli
- Department of Cell Physiology and Molecular Biophysics, Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, TX, USA
| | - Victoria C Young
- Department of Cell Physiology and Molecular Biophysics, Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, TX, USA
| | - Ryan Sweazey
- Department of Cell Physiology and Molecular Biophysics, Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, TX, USA
| | - Alexandria Padro
- Department of Cell Physiology and Molecular Biophysics, Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, TX, USA
| | - Jeannie Lee
- Department of Neurology, Texas Tech University Health Sciences Center, Lubbock, TX, USA
| | - Tulio Bueso
- Department of Neurology, Texas Tech University Health Sciences Center, Lubbock, TX, USA
| | - Roberto M Hernandez
- Department of Neurology, Texas Tech University Health Sciences Center, Lubbock, TX, USA
| | - Jongyeol Kim
- Department of Neurology, Texas Tech University Health Sciences Center, Lubbock, TX, USA
| | - Alexander Katz
- NIH Reverse Phenotyping Core, National Institutes of Health, Bethesda, MD, USA; National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Francis Rossignol
- National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Clesson Turner
- NIH Reverse Phenotyping Core, National Institutes of Health, Bethesda, MD, USA; National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Caralynn M Wilczewski
- NIH Reverse Phenotyping Core, National Institutes of Health, Bethesda, MD, USA; National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - George L Maxwell
- Women's Health Integrated Research Center, Inova Health System, Falls Church, VA, USA
| | - Miguel Holmgren
- Molecular Neurophysiology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Jeremy D Bailoo
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, TX, USA.
| | - Sho T Yano
- National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA; Molecular Neurophysiology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA; Current address: Section of Pediatric Neurology, Department of Pediatrics, University of Chicago, Chicago, IL, USA.
| | - Pablo Artigas
- Department of Cell Physiology and Molecular Biophysics, Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, TX, USA.
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3
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Li M, Nishimura T, Takeuchi Y, Hongu T, Wang Y, Shiokawa D, Wang K, Hirose H, Sasahara A, Yano M, Ishikawa S, Inokuchi M, Ota T, Tanabe M, Tada KI, Akiyama T, Cheng X, Liu CC, Yamashita T, Sugano S, Uchida Y, Chiba T, Asahara H, Nakagawa M, Sato S, Miyagi Y, Shimamura T, Nagai LAE, Kanai A, Katoh M, Nomura S, Nakato R, Suzuki Y, Tojo A, Voon DC, Ogawa S, Okamoto K, Foukakis T, Gotoh N. FXYD3 functionally demarcates an ancestral breast cancer stem cell subpopulation with features of drug-tolerant persisters. J Clin Invest 2023; 133:e166666. [PMID: 37966117 PMCID: PMC10645391 DOI: 10.1172/jci166666] [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: 11/08/2022] [Accepted: 09/21/2023] [Indexed: 11/16/2023] Open
Abstract
The heterogeneity of cancer stem cells (CSCs) within tumors presents a challenge in therapeutic targeting. To decipher the cellular plasticity that fuels phenotypic heterogeneity, we undertook single-cell transcriptomics analysis in triple-negative breast cancer (TNBC) to identify subpopulations in CSCs. We found a subpopulation of CSCs with ancestral features that is marked by FXYD domain-containing ion transport regulator 3 (FXYD3), a component of the Na+/K+ pump. Accordingly, FXYD3+ CSCs evolve and proliferate, while displaying traits of alveolar progenitors that are normally induced during pregnancy. Clinically, FXYD3+ CSCs were persistent during neoadjuvant chemotherapy, hence linking them to drug-tolerant persisters (DTPs) and identifying them as crucial therapeutic targets. Importantly, FXYD3+ CSCs were sensitive to senolytic Na+/K+ pump inhibitors, such as cardiac glycosides. Together, our data indicate that FXYD3+ CSCs with ancestral features are drivers of plasticity and chemoresistance in TNBC. Targeting the Na+/K+ pump could be an effective strategy to eliminate CSCs with ancestral and DTP features that could improve TNBC prognosis.
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Affiliation(s)
- Mengjiao Li
- Division of Cancer Cell Biology, Cancer Research Institute, and
| | | | - Yasuto Takeuchi
- Division of Cancer Cell Biology, Cancer Research Institute, and
- Institute for Frontier Science Initiative, Kanazawa University, Kanazawa City, Japan
| | - Tsunaki Hongu
- Division of Cancer Cell Biology, Cancer Research Institute, and
| | - Yuming Wang
- Division of Cancer Cell Biology, Cancer Research Institute, and
| | - Daisuke Shiokawa
- Division of Cancer Differentiation, National Cancer Center Research Institute, Chuo-ku, Tokyo, Japan
| | - Kang Wang
- Department of Oncology-Pathology, Karolinska Institute, Karolinska University Hospital, Stockholm, Sweden
| | - Haruka Hirose
- Division of Systems Biology, Graduate School of Medicine, Nagoya University, Nagoya City, Japan
| | - Asako Sasahara
- Department of Breast and Endocrine Surgery, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Masao Yano
- Department of Surgery, Minami-machida Hospital, Machida City, Tokyo, Japan
| | - Satoko Ishikawa
- Department of Breast Oncology, Kanazawa University Hospital, Kanazawa City, Japan
| | - Masafumi Inokuchi
- Department of Breast Oncology, Kanazawa University Hospital, Kanazawa City, Japan
| | - Tetsuo Ota
- Department of Breast Oncology, Kanazawa University Hospital, Kanazawa City, Japan
| | - Masahiko Tanabe
- Department of Breast and Endocrine Surgery, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Kei-ichiro Tada
- Department of Breast and Endocrine Surgery, Nihon University, Itabashi-ku, Tokyo, Japan
| | - Tetsu Akiyama
- Laboratory of Molecular and Genetic Information, Institute for Quantitative Biosciences, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Xi Cheng
- Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China
| | - Chia-Chi Liu
- North Shore Heart Research Group, Kolling Institute, University of Sydney, Sydney, New South Wales, Australia
| | - Toshinari Yamashita
- Department of Breast and Endocrine Surgery, Kanagawa Cancer Center, Yokohama City, Kanagawa, Japan
| | - Sumio Sugano
- Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, Japan
| | - Yutaro Uchida
- Department of Systems Biomedicine, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, Japan
| | - Tomoki Chiba
- Department of Systems Biomedicine, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, Japan
| | - Hiroshi Asahara
- Department of Systems Biomedicine, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, Japan
| | - Masahiro Nakagawa
- Department of Pathology and Tumor Biology, Graduate School of Medicine, Kyoto University, Sakyo-ku, Kyoto, Japan
| | - Shinya Sato
- Molecular Pathology and Genetics Division, Kanagawa Cancer Center Research Institute, Yokohama City, Kanagawa, Japan
| | - Yohei Miyagi
- Molecular Pathology and Genetics Division, Kanagawa Cancer Center Research Institute, Yokohama City, Kanagawa, Japan
| | - Teppei Shimamura
- Division of Systems Biology, Graduate School of Medicine, Nagoya University, Nagoya City, Japan
| | | | - Akinori Kanai
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Biosciences
| | - Manami Katoh
- Department of Cardiovascular Medicine, Graduate School of Medicine
- Genome Science Division, Research Center for Advanced Science and Technology
| | - Seitaro Nomura
- Department of Cardiovascular Medicine, Graduate School of Medicine
- Genome Science Division, Research Center for Advanced Science and Technology
- Department of Frontier Cardiovascular Science, Graduate School of Medicine, and
| | - Ryuichiro Nakato
- Laboratory of Computational Genomics, Institute for Quantitative Biosciences
| | - Yutaka Suzuki
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Biosciences
| | - Arinobu Tojo
- Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, Japan
- Institute of Medical Science, The University of Tokyo, Tokyo, Japan
| | - Dominic C. Voon
- Institute for Frontier Science Initiative, Kanazawa University, Kanazawa City, Japan
- Inflammation and Epithelial Plasticity Unit, Cancer Research Institute, Kanazawa University, Kanazawa City, Japan
| | - Seishi Ogawa
- Department of Pathology and Tumor Biology, Graduate School of Medicine, Kyoto University, Sakyo-ku, Kyoto, Japan
| | - Koji Okamoto
- Division of Cancer Differentiation, National Cancer Center Research Institute, Chuo-ku, Tokyo, Japan
- Advanced Comprehensive Research Organization, Teikyo University, Itabashi-ku, Tokyo, Japan
| | - Theodoros Foukakis
- Department of Oncology-Pathology, Karolinska Institute, Karolinska University Hospital, Stockholm, Sweden
| | - Noriko Gotoh
- Division of Cancer Cell Biology, Cancer Research Institute, and
- Institute for Frontier Science Initiative, Kanazawa University, Kanazawa City, Japan
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4
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Gurler B, Gencay G, Baloglu E. Hypoxia and HIF-1α Regulate the Activity and Expression of Na,K-ATPase Subunits in H9c2 Cardiomyoblasts. Curr Issues Mol Biol 2023; 45:8277-8288. [PMID: 37886965 PMCID: PMC10605391 DOI: 10.3390/cimb45100522] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2023] [Revised: 10/08/2023] [Accepted: 10/10/2023] [Indexed: 10/28/2023] Open
Abstract
The optimal function of the Na,K-ATPase (NKA) pump is essential for the heart. In ischemic heart disease, NKA activity decreases due to the decreased expression of the pump subunits. Here, we tested whether the hypoxia-inducible transcription factor (HIF-1α), the key signaling molecule regulating the adaptation of cells to hypoxia, is involved in controlling the expression and cellular dynamics of α1- and β1-NKA isoforms and of NKA activity in in-vitro hypoxic H9c2 cardiomyoblasts. HIF-1α was silenced through adenoviral infection, and cells were kept in normoxia (19% O2) or hypoxia (1% O2) for 24 h. We investigated the mRNA and protein expression of α1-, β1-NKA using RT-qPCR and Western blot in whole-cell lysates, cell membranes, and cytoplasmic fractions after labeling the cell surface with NHS-SS-biotin and immunoprecipitation. NKA activity and intracellular ATP levels were also measured. We found that in hypoxia, silencing HIF-1α prevented the decreased mRNA expression of α1-NKA but not of β1-NKA. Hypoxia decreased the plasma membrane expression of α1-NKA and β1- NKA compared to normoxic cells. In hypoxic cells, HIF-1α silencing prevented this effect by inhibiting the internalization of α1-NKA. Total protein expression was not affected. The decreased activity of NKA in hypoxic cells was fully prevented by silencing HIF-1α independent of cellular ATP levels. This study is the first to show that in hypoxic H9c2 cardiomyoblasts, HIF-1α controls the internalization and membrane insertion of α1-NKA subunit and of NKA activity. The mechanism behind this regulation needs further investigation.
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Affiliation(s)
- Beyza Gurler
- Department of Medical Biotechnology, Institute of Health Sciences, Acibadem Mehmet Ali Aydinlar University, Istanbul 34752, Turkey;
| | - Gizem Gencay
- Department of Molecular and Translational Biomedicine, Institute of Natural and Applied Sciences, Acibadem Mehmet Ali Aydinlar University, Istanbul 34752, Turkey;
| | - Emel Baloglu
- Department of Medical Pharmacology, School of Medicine, Acibadem Mehmet Ali Aydinlar University, Istanbul 34752, Turkey
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5
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Baloglu E. Hypoxic Stress-Dependent Regulation of Na,K-ATPase in Ischemic Heart Disease. Int J Mol Sci 2023; 24:ijms24097855. [PMID: 37175562 PMCID: PMC10177966 DOI: 10.3390/ijms24097855] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2023] [Revised: 04/19/2023] [Accepted: 04/20/2023] [Indexed: 05/15/2023] Open
Abstract
In cardiomyocytes, regular activity of the Na,K-ATPase (NKA) and its Na/K pump activity is essential for maintaining ion gradients, excitability, propagation of action potentials, electro-mechanical coupling, trans-membrane Na+ and Ca2+ gradients and, thus, contractility. The activity of NKA is impaired in ischemic heart disease and heart failure, which has been attributed to decreased expression of the NKA subunits. Decreased NKA activity leads to intracellular Na+ and Ca2+ overload, diastolic dysfunction and arrhythmias. One signal likely related to these events is hypoxia, where hypoxia-inducible factors (HIF) play a critical role in the adaptation of cells to low oxygen tension. HIF activity increases in ischemic heart, hypertension, heart failure and cardiac fibrosis; thus, it might contribute to the impaired function of NKA. This review will mainly focus on the regulation of NKA in ischemic heart disease in the context of stressed myocardium and the hypoxia-HIF axis and argue on possible consequences of treatment.
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Affiliation(s)
- Emel Baloglu
- Department of Medical Pharmacology, School of Medicine, Acibadem Mehmet Ali Aydinlar University, 34752 Istanbul, Turkey
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6
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Obradovic M, Sudar-Milovanovic E, Gluvic Z, Banjac K, Rizzo M, Isenovic ER. The Na +/K +-ATPase: A potential therapeutic target in cardiometabolic diseases. Front Endocrinol (Lausanne) 2023; 14:1150171. [PMID: 36926029 PMCID: PMC10011626 DOI: 10.3389/fendo.2023.1150171] [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: 01/23/2023] [Accepted: 02/14/2023] [Indexed: 03/08/2023] Open
Abstract
Cardiometabolic diseases (CMD) are a direct consequence of modern living and contribute to the development of multisystem diseases such as cardiovascular diseases and diabetes mellitus (DM). CMD has reached epidemic proportions worldwide. A sodium pump (Na+/K+-ATPase) is found in most eukaryotic cells' membrane and controls many essential cellular functions directly or indirectly. This ion transporter and its isoforms are important in the pathogenesis of some pathological processes, including CMD. The structure and function of Na+/K+-ATPase, its expression and distribution in tissues, and its interactions with known ligands such as cardiotonic steroids and other suspected endogenous regulators are discussed in this review. In addition, we reviewed recent literature data related to the involvement of Na+/K+-ATPase activity dysfunction in CMD, focusing on the Na+/K+-ATPase as a potential therapeutic target in CMD.
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Affiliation(s)
- Milan Obradovic
- Department of Radiobiology and Molecular Genetics, “VINČA“ Institute of Nuclear Sciences - National Institute of thе Republic of Serbia, University of Belgrade, Belgrade, Serbia
| | - Emina Sudar-Milovanovic
- Department of Radiobiology and Molecular Genetics, “VINČA“ Institute of Nuclear Sciences - National Institute of thе Republic of Serbia, University of Belgrade, Belgrade, Serbia
| | - Zoran Gluvic
- University Clinical-Hospital Centre Zemun-Belgrade, Clinic of Internal medicine, School of Medicine, University of Belgrade, Belgrade, Serbia
| | - Katarina Banjac
- Department of Radiobiology and Molecular Genetics, “VINČA“ Institute of Nuclear Sciences - National Institute of thе Republic of Serbia, University of Belgrade, Belgrade, Serbia
| | - Manfredi Rizzo
- School of Medicine, Promise Department, University of Palermo, Palermo, Italy
- *Correspondence: Manfredi Rizzo,
| | - Esma R. Isenovic
- Department of Radiobiology and Molecular Genetics, “VINČA“ Institute of Nuclear Sciences - National Institute of thе Republic of Serbia, University of Belgrade, Belgrade, Serbia
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7
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Cano Portillo C, Villacreses R, Thurman AL, Pezzulo AA, Zabner J, Thornell IM. FXYD3 facilitates Na + and liquid absorption across human airway epithelia by increasing the transport capacity of the Na/K ATPase. Am J Physiol Cell Physiol 2022; 323:C1044-C1051. [PMID: 35993520 PMCID: PMC9529271 DOI: 10.1152/ajpcell.00047.2022] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Revised: 08/15/2022] [Accepted: 08/16/2022] [Indexed: 12/03/2022]
Abstract
Na/K ATPase activity is essential for ion transport across epithelia. FXYD3, a γ subunit of the Na/K ATPase, is expressed in the airway, but its function remains undetermined. Single-cell RNA sequencing and immunohistochemistry revealed that FXYD3 localizes within the basolateral membrane of all airway epithelial cells. To study FXYD3 function, we reduced FXYD3 expression using siRNA. After permeabilizing the apical membrane with nystatin, epithelia pretreated with FXYD3-targeting siRNA had lower ouabain-sensitive short-circuit currents than control epithelia. FXYD3-targeting siRNA also reduced amiloride-sensitive short-circuit currents and liquid absorption across intact epithelia. These data are consistent with FXYD3 facilitating Na+ and liquid absorption. FXYD3 may be needed to maintain the high rates of Na+ and fluid absorption observed for airway and other FXYD3-expressing epithelia.
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Affiliation(s)
- Camilo Cano Portillo
- Department of Internal Medicine, Pappajohn Biomedical Institute, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa
| | - Raul Villacreses
- Department of Internal Medicine, Pappajohn Biomedical Institute, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa
| | - Andrew L Thurman
- Department of Internal Medicine, Pappajohn Biomedical Institute, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa
| | - Alejandro A Pezzulo
- Department of Internal Medicine, Pappajohn Biomedical Institute, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa
| | - Joseph Zabner
- Department of Internal Medicine, Pappajohn Biomedical Institute, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa
| | - Ian M Thornell
- Department of Internal Medicine, Pappajohn Biomedical Institute, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa
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8
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Sostaric S, Petersen AC, Goodman CA, Gong X, Aw TJ, Brown MJ, Garnham A, Steward CH, Murphy KT, Carey KA, Leppik J, Fraser SF, Cameron-Smith D, Krum H, Snow RJ, McKenna MJ. Oral digoxin effects on exercise performance, K + regulation and skeletal muscle Na + ,K + -ATPase in healthy humans. J Physiol 2022; 600:3749-3774. [PMID: 35837833 PMCID: PMC9541254 DOI: 10.1113/jp283017] [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: 03/01/2022] [Accepted: 07/08/2022] [Indexed: 11/30/2022] Open
Abstract
Abstract We investigated whether digoxin lowered muscle Na+,K+‐ATPase (NKA), impaired muscle performance and exacerbated exercise K+ disturbances. Ten healthy adults ingested digoxin (0.25 mg; DIG) or placebo (CON) for 14 days and performed quadriceps strength and fatiguability, finger flexion (FF, 105%peak‐workrate, 3 × 1 min, fourth bout to fatigue) and leg cycling (LC, 10 min at 33% VO2peak and 67% VO2peak, 90% VO2peak to fatigue) trials using a double‐blind, crossover, randomised, counter‐balanced design. Arterial (a) and antecubital venous (v) blood was sampled (FF, LC) and muscle biopsied (LC, rest, 67% VO2peak, fatigue, 3 h after exercise). In DIG, in resting muscle, [3H]‐ouabain binding site content (OB‐Fab) was unchanged; however, bound‐digoxin removal with Digibind revealed total ouabain binding (OB+Fab) increased (8.2%, P = 0.047), indicating 7.6% NKA–digoxin occupancy. Quadriceps muscle strength declined in DIG (−4.3%, P = 0.010) but fatiguability was unchanged. During LC, in DIG (main effects), time to fatigue and [K+]a were unchanged, whilst [K+]v was lower (P = 0.042) and [K+]a‐v greater (P = 0.004) than in CON; with exercise (main effects), muscle OB‐Fab was increased at 67% VO2peak (per wet‐weight, P = 0.005; per protein P = 0.001) and at fatigue (per protein, P = 0.003), whilst [K+]a, [K+]v and [K+]a‐v were each increased at fatigue (P = 0.001). During FF, in DIG (main effects), time to fatigue, [K+]a, [K+]v and [K+]a‐v were unchanged; with exercise (main effects), plasma [K+]a, [K+]v, [K+]a‐v and muscle K+ efflux were all increased at fatigue (P = 0.001). Thus, muscle strength declined, but functional muscle NKA content was preserved during DIG, despite elevated plasma digoxin and muscle NKA–digoxin occupancy, with K+ disturbances and fatiguability unchanged.
![]() Key points The Na+,K+‐ATPase (NKA) is vital in regulating skeletal muscle extracellular potassium concentration ([K+]), excitability and plasma [K+] and thereby also in modulating fatigue during intense contractions.
NKA is inhibited by digoxin, which in cardiac patients lowers muscle functional NKA content ([3H]‐ouabain binding) and exacerbates K+ disturbances during exercise. In healthy adults, we found that digoxin at clinical levels surprisingly did not reduce functional muscle NKA content, whilst digoxin removal by Digibind antibody revealed an ∼8% increased muscle total NKA content. Accordingly, digoxin did not exacerbate arterial plasma [K+] disturbances or worsen fatigue during intense exercise, although quadriceps muscle strength was reduced. Thus, digoxin treatment in healthy participants elevated serum digoxin, but muscle functional NKA content was preserved, whilst K+ disturbances and fatigue with intense exercise were unchanged. This resilience to digoxin NKA inhibition is consistent with the importance of NKA in preserving K+ regulation and muscle function.
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Affiliation(s)
- Simon Sostaric
- Institute for Health and Sport, Victoria University, Melbourne, Australia
| | - Aaron C Petersen
- Institute for Health and Sport, Victoria University, Melbourne, Australia
| | - Craig A Goodman
- Institute for Health and Sport, Victoria University, Melbourne, Australia.,Centre for Muscle Research, Department of Anatomy and Physiology, University of Melbourne, Parkville, Australia
| | - Xiaofei Gong
- Institute for Health and Sport, Victoria University, Melbourne, Australia
| | - Tai-Juan Aw
- Department of Epidemiology and Preventive Medicine, Monash University, Alfred Hospital, Melbourne, Australia
| | - Malcolm J Brown
- Department of Biochemistry and Pharmacology, University of Melbourne, Melbourne, Australia
| | - Andrew Garnham
- Institute for Health and Sport, Victoria University, Melbourne, Australia
| | - Collene H Steward
- Institute for Health and Sport, Victoria University, Melbourne, Australia
| | - Kate T Murphy
- Institute for Health and Sport, Victoria University, Melbourne, Australia.,Centre for Muscle Research, Department of Anatomy and Physiology, University of Melbourne, Parkville, Australia
| | - Kate A Carey
- School of Women's and Children's Health, University of New South Wales, Sydney, Australia
| | - James Leppik
- Institute for Health and Sport, Victoria University, Melbourne, Australia
| | - Steve F Fraser
- Institute of Physical Activity and Nutrition, School of Exercise and Nutrition Sciences, Deakin University, Melbourne, Australia
| | - David Cameron-Smith
- Singapore Institute for Clinical Sciences, Agency for Science, Technology and Research, Singapore
| | - Henry Krum
- Department of Epidemiology and Preventive Medicine, Monash University, Alfred Hospital, Melbourne, Australia
| | - Rodney J Snow
- Institute of Physical Activity and Nutrition, School of Exercise and Nutrition Sciences, Deakin University, Melbourne, Australia
| | - Michael J McKenna
- Institute for Health and Sport, Victoria University, Melbourne, Australia
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9
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Liu CC, Kim YJ, Teh R, Garcia A, Hamilton EJ, Cornelius F, Baxter RC, Rasmussen HH. Displacement of Native FXYD Protein From Na+/K+-ATPase With Novel FXYD Peptide Derivatives: Effects on Doxorubicin Cytotoxicity. Front Oncol 2022; 12:859216. [PMID: 35371992 PMCID: PMC8968713 DOI: 10.3389/fonc.2022.859216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Accepted: 02/21/2022] [Indexed: 11/13/2022] Open
Abstract
The seven mammalian FXYD proteins associate closely with α/β heterodimers of Na+/K+-ATPase. Most of them protect the β1 subunit against glutathionylation, an oxidative modification that destabilizes the heterodimer and inhibits Na+/K+-ATPase activity. A specific cysteine (Cys) residue of FXYD proteins is critical for such protection. One of the FXYD proteins, FXYD3, confers treatment resistance when overexpressed in cancer cells. We developed two FXYD3 peptide derivatives. FXYD3-pep CKCK retained the Cys residue that can undergo glutathionylation and that is critical for protecting the β1 subunit against glutathionylation. FXYD3-pep SKSK had all Cys residues mutated to Serine (Ser). The chemotherapeutic doxorubicin induces oxidative stress, and suppression of FXYD3 with siRNA in pancreatic- and breast cancer cells that strongly express FXYD3 increased doxorubicin-induced cytotoxicity. Exposing cells to FXYD3-pep SKSK decreased co-immunoprecipitation of FXYD3 with the α1 Na+/K+-ATPase subunit. FXYD3-pep SKSK reproduced the increase in doxorubicin-induced cytotoxicity seen after FXYD3 siRNA transfection in pancreatic- and breast cancer cells that overexpressed FXYD3, while FXYD3-pep CKCK boosted the native protein’s protection against doxorubicin. Neither peptide affected doxorubicin’s cytotoxicity on cells with no or low FXYD3 expression. Fluorescently labeled FXYD3-pep SKSK was detected in a perinuclear distribution in the cells overexpressing FXYD3, and plasmalemmal Na+/K+-ATPase turnover could not be implicated in the increased sensitivity to doxorubicin that FXYD3-pep SKSK caused. FXYD peptide derivatives allow rapid elimination or amplification of native FXYD protein function. Here, their effects implicate the Cys residue that is critical for countering β1 subunit glutathionylation in the augmentation of cytotoxicity with siRNA-induced downregulation of FXYD3.
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Affiliation(s)
- Chia-Chi Liu
- North Shore Heart Research Group, Kolling Medical Research Institute, University of Sydney, St Leonards, NSW, Australia
- *Correspondence: Chia-Chi Liu, ; Helge H. Rasmussen,
| | - Yeon Jae Kim
- North Shore Heart Research Group, Kolling Medical Research Institute, University of Sydney, St Leonards, NSW, Australia
| | - Rachel Teh
- North Shore Heart Research Group, Kolling Medical Research Institute, University of Sydney, St Leonards, NSW, Australia
| | - Alvaro Garcia
- School of Chemistry, University of Sydney, Camperdown, NSW, Australia
| | - Elisha J. Hamilton
- North Shore Heart Research Group, Kolling Medical Research Institute, University of Sydney, St Leonards, NSW, Australia
| | | | - Robert C. Baxter
- Hormones and Cancer Laboratories, Kolling Institute, University of Sydney, St Leonards, NSW, Australia
| | - Helge H. Rasmussen
- North Shore Heart Research Group, Kolling Medical Research Institute, University of Sydney, St Leonards, NSW, Australia
- Department of Cardiology, Royal North Shore Hospital, St Leonards, NSW, Australia
- *Correspondence: Chia-Chi Liu, ; Helge H. Rasmussen,
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10
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Cassol G, Cipolat RP, Papalia WL, Godinho DB, Quines CB, Nogueira CW, Da Veiga M, Da Rocha MIUM, Furian AF, Oliveira MS, Fighera MR, Royes LFF. A role of Na+, K+ -ATPase in spatial memory deficits and inflammatory/oxidative stress after recurrent concussion in adolescent rats. Brain Res Bull 2021; 180:1-11. [PMID: 34954227 DOI: 10.1016/j.brainresbull.2021.12.009] [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: 07/26/2021] [Revised: 12/02/2021] [Accepted: 12/20/2021] [Indexed: 11/28/2022]
Abstract
Sports-related concussions are particularly common during adolescence, and there is insufficient knowledge about how recurrent concussions in this phase of life alter the metabolism of essential structures for memory in adulthood. In this sense, our experimental data revealed that seven recurrent concussions (RC) in 35-day-old rats decreased short-term and long-term memory in the object recognition test (ORT) 30 days after injury. The RC protocol did not alter motor and anxious behavior and the immunoreactivity of brain-derived neurotrophic factor (BDNF) in the cerebral cortex. Recurrent concussions induced the inflammatory/oxidative stress characterized here by increased glial fibrillary acidic protein (GFAP), interleukin 1β (IL 1β), 4-hydroxynonenal (4 HNE), protein carbonyl immunoreactivity, and 2',7'-dichlorofluorescein diacetate oxidation (DCFH) levels and lower total antioxidant capacity (TAC). Inhibited Na+,K+-ATPase activity (specifically isoform α2/3) followed by Km (Michaelis-Menten constant) for increased ATP levels and decreased immunodetection of alpha subunit of this enzyme, suggesting that cognitive impairment after RC is caused by the inability of surviving neurons to maintain ionic gradients in selected targets to inflammatory/oxidative damage, such as Na,K-ATPase activity.
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Affiliation(s)
- G Cassol
- Exercise Biochemistry Laboratory, Center of Physical Education and Sports, Brazil; Postgraduate Program in Physical Education, Brazil; Federal University of Santa Maria - UFSM, Santa Maria, RS, Brazil
| | - R P Cipolat
- Exercise Biochemistry Laboratory, Center of Physical Education and Sports, Brazil; Postgraduate Program in Biological Sciences: Toxicological Biochemistry, Brazil; Federal University of Santa Maria - UFSM, Santa Maria, RS, Brazil
| | - W L Papalia
- Exercise Biochemistry Laboratory, Center of Physical Education and Sports, Brazil; Postgraduate Program in Biological Sciences: Toxicological Biochemistry, Brazil; Federal University of Santa Maria - UFSM, Santa Maria, RS, Brazil
| | - D B Godinho
- Exercise Biochemistry Laboratory, Center of Physical Education and Sports, Brazil; Postgraduate Program in Biological Sciences: Toxicological Biochemistry, Brazil; Federal University of Santa Maria - UFSM, Santa Maria, RS, Brazil
| | - C B Quines
- Postgraduate Program in Biological Sciences: Toxicological Biochemistry, Brazil; Federal University of Santa Maria - UFSM, Santa Maria, RS, Brazil
| | - C W Nogueira
- Postgraduate Program in Biological Sciences: Toxicological Biochemistry, Brazil; Federal University of Santa Maria - UFSM, Santa Maria, RS, Brazil
| | - M Da Veiga
- Department of Morphology, Health Sciences Center, Brazil; Federal University of Santa Maria - UFSM, Santa Maria, RS, Brazil
| | - M I U M Da Rocha
- Department of Morphology, Health Sciences Center, Brazil; Federal University of Santa Maria - UFSM, Santa Maria, RS, Brazil
| | - A F Furian
- Laboratory of Neurotoxicity and Psychopharmacology, Health Sciences Center, Brazil; Federal University of Santa Maria - UFSM, Santa Maria, RS, Brazil
| | - M S Oliveira
- Laboratory of Neurotoxicity and Psychopharmacology, Health Sciences Center, Brazil; Federal University of Santa Maria - UFSM, Santa Maria, RS, Brazil
| | - M R Fighera
- Exercise Biochemistry Laboratory, Center of Physical Education and Sports, Brazil; Postgraduate Program in Biological Sciences: Toxicological Biochemistry, Brazil; Department of Internal Medicine and Pediatrics, Health Sciences Center, Brazil; Federal University of Santa Maria - UFSM, Santa Maria, RS, Brazil
| | - L F F Royes
- Exercise Biochemistry Laboratory, Center of Physical Education and Sports, Brazil; Postgraduate Program in Physical Education, Brazil; Postgraduate Program in Biological Sciences: Toxicological Biochemistry, Brazil; Federal University of Santa Maria - UFSM, Santa Maria, RS, Brazil.
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11
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Meyer DJ, Bijlani S, de Sautu M, Spontarelli K, Young VC, Gatto C, Artigas P. FXYD protein isoforms differentially modulate human Na/K pump function. J Gen Physiol 2021; 152:211559. [PMID: 33231612 PMCID: PMC7690937 DOI: 10.1085/jgp.202012660] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Accepted: 10/29/2020] [Indexed: 12/28/2022] Open
Abstract
Tight regulation of the Na/K pump is essential for cellular function because this heteromeric protein builds and maintains the electrochemical gradients for Na+ and K+ that energize electrical signaling and secondary active transport. We studied the regulation of the ubiquitous human α1β1 pump isoform by five human FXYD proteins normally located in muscle, kidney, and neurons. The function of Na/K pump α1β1 expressed in Xenopus oocytes with or without FXYD isoforms was evaluated using two-electrode voltage clamp and patch clamp. Through evaluation of the partial reactions in the absence of K+ but presence of Na+ in the external milieu, we demonstrate that each FXYD subunit alters the equilibrium between E1P(3Na) and E2P, the phosphorylated conformations with Na+ occluded and free from Na+, respectively, thereby altering the apparent affinity for Na+. This modification of Na+ interaction shapes the small effects of FXYD proteins on the apparent affinity for external K+ at physiological Na+. FXYD6 distinctively accelerated both the Na+-deocclusion and the pump-turnover rates. All FXYD isoforms altered the apparent affinity for intracellular Na+ in patches, an effect that was observed only in the presence of intracellular K+. Therefore, FXYD proteins alter the selectivity of the pump for intracellular ions, an effect that could be due to the altered equilibrium between E1 and E2, the two major pump conformations, and/or to small changes in ion affinities that are exacerbated when both ions are present. Lastly, we observed a drastic reduction of Na/K pump surface expression when it was coexpressed with FXYD1 or FXYD6, with the former being relieved by injection of PKA's catalytic subunit into the oocyte. Our results indicate that a prominent effect of FXYD1 and FXYD6, and plausibly other FXYDs, is the regulation of Na/K pump trafficking.
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Affiliation(s)
- Dylan J Meyer
- Department of Cell Physiology and Molecular Biophysics, Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock TX
| | - Sharan Bijlani
- Department of Cell Physiology and Molecular Biophysics, Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock TX
| | - Marilina de Sautu
- Department of Cell Physiology and Molecular Biophysics, Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock TX
| | - Kerri Spontarelli
- Department of Cell Physiology and Molecular Biophysics, Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock TX
| | - Victoria C Young
- Department of Cell Physiology and Molecular Biophysics, Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock TX
| | - Craig Gatto
- School of Biological Sciences, Illinois State University. Normal, IL
| | - Pablo Artigas
- Department of Cell Physiology and Molecular Biophysics, Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock TX
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12
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Hostrup M, Cairns SP, Bangsbo J. Muscle Ionic Shifts During Exercise: Implications for Fatigue and Exercise Performance. Compr Physiol 2021; 11:1895-1959. [PMID: 34190344 DOI: 10.1002/cphy.c190024] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Exercise causes major shifts in multiple ions (e.g., K+ , Na+ , H+ , lactate- , Ca2+ , and Cl- ) during muscle activity that contributes to development of muscle fatigue. Sarcolemmal processes can be impaired by the trans-sarcolemmal rundown of ion gradients for K+ , Na+ , and Ca2+ during fatiguing exercise, while changes in gradients for Cl- and Cl- conductance may exert either protective or detrimental effects on fatigue. Myocellular H+ accumulation may also contribute to fatigue development by lowering glycolytic rate and has been shown to act synergistically with inorganic phosphate (Pi) to compromise cross-bridge function. In addition, sarcoplasmic reticulum Ca2+ release function is severely affected by fatiguing exercise. Skeletal muscle has a multitude of ion transport systems that counter exercise-related ionic shifts of which the Na+ /K+ -ATPase is of major importance. Metabolic perturbations occurring during exercise can exacerbate trans-sarcolemmal ionic shifts, in particular for K+ and Cl- , respectively via metabolic regulation of the ATP-sensitive K+ channel (KATP ) and the chloride channel isoform 1 (ClC-1). Ion transport systems are highly adaptable to exercise training resulting in an enhanced ability to counter ionic disturbances to delay fatigue and improve exercise performance. In this article, we discuss (i) the ionic shifts occurring during exercise, (ii) the role of ion transport systems in skeletal muscle for ionic regulation, (iii) how ionic disturbances affect sarcolemmal processes and muscle fatigue, (iv) how metabolic perturbations exacerbate ionic shifts during exercise, and (v) how pharmacological manipulation and exercise training regulate ion transport systems to influence exercise performance in humans. © 2021 American Physiological Society. Compr Physiol 11:1895-1959, 2021.
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Affiliation(s)
- Morten Hostrup
- Section of Integrative Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Simeon Peter Cairns
- SPRINZ, School of Sport and Recreation, Auckland University of Technology, Auckland, New Zealand.,Health and Rehabilitation Research Institute, Auckland University of Technology, Auckland, New Zealand
| | - Jens Bangsbo
- Section of Integrative Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
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13
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Khadrawy YA, Hosny EN, El-Gizawy MM, Sawie HG, Aboul Ezz HS. The Effect of Curcumin Nanoparticles on Cisplatin-Induced Cardiotoxicity in Male Wistar Albino Rats. Cardiovasc Toxicol 2021; 21:433-443. [PMID: 33548025 DOI: 10.1007/s12012-021-09636-3] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Accepted: 01/25/2021] [Indexed: 01/06/2023]
Abstract
The cardiotoxicity of chemotherapeutic drugs as cisplatin has become a major issue in recent years. The present study investigates the efficacy of curcumin nanoparticles against the cardiotoxic effects of cisplatin by assessment of oxidative stress parameters, Na+,K+-ATPase, acetylcholinesterase (AchE) and tumor necrosis factor-alpha (TNF-α) in cardiac tissue in addition to serum lactate dehydrogenase (LDH). Rats were divided into three groups: control rats that received saline for 14 days; cisplatin-treated rats that received a single intraperitoneal (i.p.) injection of cisplatin (12 mg/kg) followed by a daily oral administration of saline (0.9%) for 14 days and rats treated with a single i.p. injection of cisplatin (12 mg/kg) followed by a daily oral administration of curcumin nanoparticles (50 mg/kg) for 14 days. Cisplatin resulted in a significant increase in lipid peroxidation, nitric oxide (NO), and TNF-α and a significant decrease in reduced glutathione (GSH) levels and Na+, K+- ATPase activity. Moreover, significant increases in cardiac AchE and serum lactate dehydrogenase activities were recorded. Treatment of cisplatin-injected animals with curcumin nanoparticles ameliorated all the alterations induced by cisplatin in the heart of rats. This suggests that curcumin nanoparticles can be used as an important therapeutic adjuvant in chemotherapeutic and other toxicities mediated by oxidative stress and inflammation.
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Affiliation(s)
- Yasser A Khadrawy
- Medical Physiology Department, Medical Division, National Research Centre, El-Behouth St., Giza, Egypt.
| | - Eman N Hosny
- Medical Physiology Department, Medical Division, National Research Centre, El-Behouth St., Giza, Egypt
| | - Mayada M El-Gizawy
- Medical Physiology Department, Medical Division, National Research Centre, El-Behouth St., Giza, Egypt
| | - Hussein G Sawie
- Medical Physiology Department, Medical Division, National Research Centre, El-Behouth St., Giza, Egypt
| | - Heba S Aboul Ezz
- Zoology Department, Faculty of Science, Cairo University, Giza, Egypt
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14
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Bubb KJ, Tang O, Gentile C, Moosavi SM, Hansen T, Liu CC, Di Bartolo BA, Figtree GA. FXYD1 Is Protective Against Vascular Dysfunction. Hypertension 2021; 77:2104-2116. [PMID: 33934624 DOI: 10.1161/hypertensionaha.120.16884] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
[Figure: see text].
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Affiliation(s)
- Kristen J Bubb
- From the University of Sydney, Kolling Institute of Medical Research, Cardiothoracic and Vascular Health (K.J.B., O.T., C.G., S.M.M., T.H., C.-C.L., B.A.D.B., G.A.F.).,Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia (K.J.B.)
| | - Owen Tang
- From the University of Sydney, Kolling Institute of Medical Research, Cardiothoracic and Vascular Health (K.J.B., O.T., C.G., S.M.M., T.H., C.-C.L., B.A.D.B., G.A.F.).,Royal North Shore Hospital, St Leonards, NSW, Australia (O.T., T.H., C.-C.L., B.A.D.B., G.A.F.)
| | - Carmine Gentile
- From the University of Sydney, Kolling Institute of Medical Research, Cardiothoracic and Vascular Health (K.J.B., O.T., C.G., S.M.M., T.H., C.-C.L., B.A.D.B., G.A.F.).,University of Technology Sydney, Ultimo, NSW, Australia (C.G., S.M.M.)
| | - Seyed M Moosavi
- From the University of Sydney, Kolling Institute of Medical Research, Cardiothoracic and Vascular Health (K.J.B., O.T., C.G., S.M.M., T.H., C.-C.L., B.A.D.B., G.A.F.).,University of Technology Sydney, Ultimo, NSW, Australia (C.G., S.M.M.)
| | - Thomas Hansen
- From the University of Sydney, Kolling Institute of Medical Research, Cardiothoracic and Vascular Health (K.J.B., O.T., C.G., S.M.M., T.H., C.-C.L., B.A.D.B., G.A.F.).,Royal North Shore Hospital, St Leonards, NSW, Australia (O.T., T.H., C.-C.L., B.A.D.B., G.A.F.)
| | - Chia-Chi Liu
- From the University of Sydney, Kolling Institute of Medical Research, Cardiothoracic and Vascular Health (K.J.B., O.T., C.G., S.M.M., T.H., C.-C.L., B.A.D.B., G.A.F.).,Royal North Shore Hospital, St Leonards, NSW, Australia (O.T., T.H., C.-C.L., B.A.D.B., G.A.F.).,Heart Research Institute, Newtown, NSW, Australia (C.-C.L.)
| | - Belinda A Di Bartolo
- From the University of Sydney, Kolling Institute of Medical Research, Cardiothoracic and Vascular Health (K.J.B., O.T., C.G., S.M.M., T.H., C.-C.L., B.A.D.B., G.A.F.).,Royal North Shore Hospital, St Leonards, NSW, Australia (O.T., T.H., C.-C.L., B.A.D.B., G.A.F.)
| | - Gemma A Figtree
- From the University of Sydney, Kolling Institute of Medical Research, Cardiothoracic and Vascular Health (K.J.B., O.T., C.G., S.M.M., T.H., C.-C.L., B.A.D.B., G.A.F.).,Royal North Shore Hospital, St Leonards, NSW, Australia (O.T., T.H., C.-C.L., B.A.D.B., G.A.F.)
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15
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Bejček J, Spiwok V, Kmoníčková E, Rimpelová S. Na +/K +-ATPase Revisited: On Its Mechanism of Action, Role in Cancer, and Activity Modulation. Molecules 2021; 26:molecules26071905. [PMID: 33800655 PMCID: PMC8061769 DOI: 10.3390/molecules26071905] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 03/18/2021] [Accepted: 03/24/2021] [Indexed: 01/08/2023] Open
Abstract
Maintenance of Na+ and K+ gradients across the cell plasma membrane is an essential process for mammalian cell survival. An enzyme responsible for this process, sodium-potassium ATPase (NKA), has been currently extensively studied as a potential anticancer target, especially in lung cancer and glioblastoma. To date, many NKA inhibitors, mainly of natural origin from the family of cardiac steroids (CSs), have been reported and extensively studied. Interestingly, upon CS binding to NKA at nontoxic doses, the role of NKA as a receptor is activated and intracellular signaling is triggered, upon which cancer cell death occurs, which lies in the expression of different NKA isoforms than in healthy cells. Two major CSs, digoxin and digitoxin, originally used for the treatment of cardiac arrhythmias, are also being tested for another indication—cancer. Such drug repositioning has a big advantage in smoother approval processes. Besides this, novel CS derivatives with improved performance are being developed and evaluated in combination therapy. This article deals with the NKA structure, mechanism of action, activity modulation, and its most important inhibitors, some of which could serve not only as a powerful tool to combat cancer, but also help to decipher the so-far poorly understood NKA regulation.
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Affiliation(s)
- Jiří Bejček
- Department of Biochemistry and Microbiology, University of Chemistry and Technology Prague, Technická 3, 166 28 Prague 6, Czech Republic; (J.B.); (V.S.)
| | - Vojtěch Spiwok
- Department of Biochemistry and Microbiology, University of Chemistry and Technology Prague, Technická 3, 166 28 Prague 6, Czech Republic; (J.B.); (V.S.)
| | - Eva Kmoníčková
- Department of Pharmacology, Second Faculty of Medicine, Charles University, Plzeňská 311, 150 00 Prague, Czech Republic;
| | - Silvie Rimpelová
- Department of Biochemistry and Microbiology, University of Chemistry and Technology Prague, Technická 3, 166 28 Prague 6, Czech Republic; (J.B.); (V.S.)
- Faculty of Medicine in Pilsen, Charles University, Alej Svobody 76, 323 00 Pilsen, Czech Republic
- Correspondence: ; Tel.: +420-220-444-360
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16
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Yap JQ, Seflova J, Sweazey R, Artigas P, Robia SL. FXYD proteins and sodium pump regulatory mechanisms. J Gen Physiol 2021; 153:211866. [PMID: 33688925 PMCID: PMC7953255 DOI: 10.1085/jgp.202012633] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2020] [Accepted: 02/03/2021] [Indexed: 12/12/2022] Open
Abstract
The sodium/potassium-ATPase (NKA) is the enzyme that establishes gradients of sodium and potassium across the plasma membrane. NKA activity is tightly regulated for different physiological contexts through interactions with single-span transmembrane peptides, the FXYD proteins. This diverse family of regulators has in common a domain containing a Phe-X-Tyr-Asp (FXYD) motif, two conserved glycines, and one serine residue. In humans, there are seven tissue-specific FXYD proteins that differentially modulate NKA kinetics as appropriate for each system, providing dynamic responsiveness to changing physiological conditions. Our understanding of how FXYD proteins contribute to homeostasis has benefitted from recent advances described in this review: biochemical and biophysical studies have provided insight into regulatory mechanisms, genetic models have uncovered remarkable complexity of FXYD function in integrated physiological systems, new posttranslational modifications have been identified, high-resolution structural studies have revealed new details of the regulatory interaction with NKA, and new clinical correlations have been uncovered. In this review, we address the structural determinants of diverse FXYD functions and the special roles of FXYDs in various physiological systems. We also discuss the possible roles of FXYDs in protein trafficking and regulation of non-NKA targets.
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Affiliation(s)
- John Q Yap
- Department of Cell and Molecular Physiology, Loyola University Chicago, Maywood, IL
| | - Jaroslava Seflova
- Department of Cell and Molecular Physiology, Loyola University Chicago, Maywood, IL
| | - Ryan Sweazey
- Department of Cell Physiology and Molecular Biophysics, Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, TX
| | - Pablo Artigas
- Department of Cell Physiology and Molecular Biophysics, Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, TX
| | - Seth L Robia
- Department of Cell and Molecular Physiology, Loyola University Chicago, Maywood, IL
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17
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Petrushanko IY, Mitkevich VA, Makarov AA. Molecular Mechanisms of the Redox Regulation of the Na,K-ATPase. Biophysics (Nagoya-shi) 2020. [DOI: 10.1134/s0006350920050139] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
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18
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Molecular mechanisms by which iNOS uncoupling can induce cardiovascular dysfunction during sepsis: Role of posttranslational modifications (PTMs). Life Sci 2020; 255:117821. [PMID: 32445759 DOI: 10.1016/j.lfs.2020.117821] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Revised: 05/14/2020] [Accepted: 05/18/2020] [Indexed: 01/01/2023]
Abstract
Human sepsis is the result of a multifaceted pathological process causing marked dysregulation of cardiovascular responses. A more sophisticated understanding of the pathogenesis of sepsis is certainly prerequisite. Evidence from studies provide further insight into the role of inducible nitric oxide synthase (iNOS) isoform. Results on inhibition of iNOS in sepsis models remain inconclusive. Concern has been devoted to improving our knowledge and understanding of the role of iNOS. The aim of this review is to define the role of iNOS in redox homeostasis disturbance, the detailed mechanisms linking iNOS and posttranslational modifications (PTMs) to cardiovascular dysfunctions, and their future implications in sepsis settings. Many questions related to the iNOS and PTMs still remain open, and much more work is needed on this.
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19
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Liu J, Nie Y, Chaudhry M, Bai F, Chuang J, Sodhi K, Shapiro JI. The Redox-Sensitive Na/K-ATPase Signaling in Uremic Cardiomyopathy. Int J Mol Sci 2020; 21:ijms21041256. [PMID: 32069992 PMCID: PMC7072896 DOI: 10.3390/ijms21041256] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Revised: 02/10/2020] [Accepted: 02/10/2020] [Indexed: 02/07/2023] Open
Abstract
In recent years, Na/K-ATPase signaling has been implicated in different physiological and pathophysiological conditions, including cardiac hypertrophy and uremic cardiomyopathy. Cardiotonic steroids (CTS), specific ligands of Na/K-ATPase, regulate its enzymatic activity (at higher concentrations) and signaling function (at lower concentrations without significantly affecting its enzymatic activity) and increase reactive oxygen species (ROS) generation. On the other hand, an increase in ROS alone also regulates the Na/K-ATPase enzymatic activity and signaling function. We termed this phenomenon the Na/K-ATPase-mediated oxidant-amplification loop, in which oxidative stress regulates both the Na/K-ATPase activity and signaling. Most recently, we also demonstrated that this amplification loop is involved in the development of uremic cardiomyopathy. This review aims to evaluate the redox-sensitive Na/K-ATPase-mediated oxidant amplification loop and uremic cardiomyopathy.
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Affiliation(s)
- Jiang Liu
- Department of Biomedical Sciences, Joan C. Edwards School of Medicine, Marshall University, Huntington, WV 25755, USA; (Y.N.); (M.C.); (F.B.)
- Correspondence:
| | - Ying Nie
- Department of Biomedical Sciences, Joan C. Edwards School of Medicine, Marshall University, Huntington, WV 25755, USA; (Y.N.); (M.C.); (F.B.)
| | - Muhammad Chaudhry
- Department of Biomedical Sciences, Joan C. Edwards School of Medicine, Marshall University, Huntington, WV 25755, USA; (Y.N.); (M.C.); (F.B.)
| | - Fang Bai
- Department of Biomedical Sciences, Joan C. Edwards School of Medicine, Marshall University, Huntington, WV 25755, USA; (Y.N.); (M.C.); (F.B.)
| | - Justin Chuang
- Department of Medicine, Joan C. Edwards School of Medicine, Marshall University, Huntington, WV 25755, USA; (J.C.); (K.S.); (J.I.S.)
| | - Komal Sodhi
- Department of Medicine, Joan C. Edwards School of Medicine, Marshall University, Huntington, WV 25755, USA; (J.C.); (K.S.); (J.I.S.)
| | - Joseph I. Shapiro
- Department of Medicine, Joan C. Edwards School of Medicine, Marshall University, Huntington, WV 25755, USA; (J.C.); (K.S.); (J.I.S.)
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20
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Yoneda JS, Sebinelli HG, Itri R, Ciancaglini P. Overview on solubilization and lipid reconstitution of Na,K-ATPase: enzyme kinetic and biophysical characterization. Biophys Rev 2020; 12:49-64. [PMID: 31955383 DOI: 10.1007/s12551-020-00616-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Accepted: 01/07/2020] [Indexed: 12/11/2022] Open
Abstract
Na,K-ATPase is a membrane protein which plays a vital role. It pumps Na+ and K+ ions across the cellular membranes using energy from ATP hydrolysis, and is responsible for maintaining the osmotic equilibrium and generating the membrane potential. Moreover, Na,K-ATPase has also been involved in cell signaling, interacting with partner proteins. Cardiotonic steroids bind specifically to Na,K-ATPase triggering a number of signaling pathways. Because of its importance, many efforts have been employed to study the structure and function of this protein. Difficulties associated with its removal from natural membranes and the concomitant search for appropriate replacement conditions to keep the protein in solution have presented a challenge that had to be overcome prior to carrying out biophysical and biochemical studies in vitro. In this review, we summarized all of the methods and techniques applied by our group in order to obtain information about Na,K-ATPase in respect to solubilization, reconstitution into mimetic system, influence of lipid composition, stability, oligomerization, and aggregation.
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Affiliation(s)
- Juliana Sakamoto Yoneda
- Instituto de Fisica, Universidade de Sao Paulo, Rua do Matao, 1371, 05508-090, Sao Paulo, SP, Brazil.
| | - Heitor Gobbi Sebinelli
- Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto da Universidade de São Paulo (FFCLRP-USP), Ribeirão Preto, SP, 14040-901, Brazil
| | - Rosangela Itri
- Instituto de Fisica, Universidade de Sao Paulo, Rua do Matao, 1371, 05508-090, Sao Paulo, SP, Brazil
| | - Pietro Ciancaglini
- Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto da Universidade de São Paulo (FFCLRP-USP), Ribeirão Preto, SP, 14040-901, Brazil
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21
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Blaustein MP, Hamlyn JM. Ouabain, endogenous ouabain and ouabain-like factors: The Na + pump/ouabain receptor, its linkage to NCX, and its myriad functions. Cell Calcium 2020; 86:102159. [PMID: 31986323 DOI: 10.1016/j.ceca.2020.102159] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2019] [Revised: 01/01/2020] [Accepted: 01/03/2020] [Indexed: 12/12/2022]
Abstract
In this brief review we discuss some aspects of the Na+ pump and its roles in mediating the effects of ouabain and endogenous ouabain (EO): i) in regulating the cytosolic Ca2+ concentration ([Ca2+]CYT) via Na/Ca exchange (NCX), and ii) in activating a number of protein kinase (PK) signaling cascades that control a myriad of cell functions. Importantly, [Ca2+]CYT and the other signaling pathways intersect at numerous points because of the influence of Ca2+ and calmodulin in modulating some steps in those other pathways. While both mechanisms operate in virtually all cells and tissues, this article focuses primarily on their functions in the cardiovascular system, the central nervous system (CNS) and the kidneys.
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Affiliation(s)
- Mordecai P Blaustein
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA; Department of Medicine, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
| | - John M Hamlyn
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
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22
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Chia SB, Elko EA, Aboushousha R, Manuel AM, van de Wetering C, Druso JE, van der Velden J, Seward DJ, Anathy V, Irvin CG, Lam YW, van der Vliet A, Janssen-Heininger YMW. Dysregulation of the glutaredoxin/ S-glutathionylation redox axis in lung diseases. Am J Physiol Cell Physiol 2019; 318:C304-C327. [PMID: 31693398 DOI: 10.1152/ajpcell.00410.2019] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Glutathione is a major redox buffer, reaching millimolar concentrations within cells and high micromolar concentrations in airways. While glutathione has been traditionally known as an antioxidant defense mechanism that protects the lung tissue from oxidative stress, glutathione more recently has become recognized for its ability to become covalently conjugated to reactive cysteines within proteins, a modification known as S-glutathionylation (or S-glutathiolation or protein mixed disulfide). S-glutathionylation has the potential to change the structure and function of the target protein, owing to its size (the addition of three amino acids) and charge (glutamic acid). S-glutathionylation also protects proteins from irreversible oxidation, allowing them to be enzymatically regenerated. Numerous enzymes have been identified to catalyze the glutathionylation/deglutathionylation reactions, including glutathione S-transferases and glutaredoxins. Although protein S-glutathionylation has been implicated in numerous biological processes, S-glutathionylated proteomes have largely remained unknown. In this paper, we focus on the pathways that regulate GSH homeostasis, S-glutathionylated proteins, and glutaredoxins, and we review methods required toward identification of glutathionylated proteomes. Finally, we present the latest findings on the role of glutathionylation/glutaredoxins in various lung diseases: idiopathic pulmonary fibrosis, asthma, and chronic obstructive pulmonary disease.
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Affiliation(s)
- Shi B Chia
- Department of Pathology and Laboratory Medicine, University of Vermont, Burlington, Vermont
| | - Evan A Elko
- Department of Pathology and Laboratory Medicine, University of Vermont, Burlington, Vermont
| | - Reem Aboushousha
- Department of Pathology and Laboratory Medicine, University of Vermont, Burlington, Vermont
| | - Allison M Manuel
- Department of Pathology and Laboratory Medicine, University of Vermont, Burlington, Vermont
| | - Cheryl van de Wetering
- Department of Pathology and Laboratory Medicine, University of Vermont, Burlington, Vermont
| | - Joseph E Druso
- Department of Pathology and Laboratory Medicine, University of Vermont, Burlington, Vermont
| | - Jos van der Velden
- Department of Pathology and Laboratory Medicine, University of Vermont, Burlington, Vermont
| | - David J Seward
- Department of Pathology and Laboratory Medicine, University of Vermont, Burlington, Vermont
| | - Vikas Anathy
- Department of Pathology and Laboratory Medicine, University of Vermont, Burlington, Vermont
| | - Charles G Irvin
- Department of Medicine, University of Vermont, Burlington, Vermont
| | - Ying-Wai Lam
- Department of Biology, University of Vermont, Burlington, Vermont
| | - Albert van der Vliet
- Department of Pathology and Laboratory Medicine, University of Vermont, Burlington, Vermont
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23
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Christiansen D, Eibye KH, Rasmussen V, Voldbye HM, Thomassen M, Nyberg M, Gunnarsson TGP, Skovgaard C, Lindskrog MS, Bishop DJ, Hostrup M, Bangsbo J. Cycling with blood flow restriction improves performance and muscle K + regulation and alters the effect of anti-oxidant infusion in humans. J Physiol 2019; 597:2421-2444. [PMID: 30843602 DOI: 10.1113/jp277657] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2019] [Accepted: 02/27/2019] [Indexed: 12/14/2022] Open
Abstract
KEY POINTS Training with blood flow restriction (BFR) is a well-recognized strategy for promoting muscle hypertrophy and strength. However, its potential to enhance muscle function during sustained, intense exercise remains largely unexplored. In the present study, we report that interval training with BFR augments improvements in performance and reduces net K+ release from contracting muscles during high-intensity exercise in active men. A better K+ regulation after BFR-training is associated with an elevated blood flow to exercising muscles and altered muscle anti-oxidant function, as indicated by a higher reduced to oxidized glutathione (GSH:GSSG) ratio, compared to control, as well as an increased thigh net K+ release during intense exercise with concomitant anti-oxidant infusion. Training with BFR also invoked fibre type-specific adaptations in the abundance of Na+ ,K+ -ATPase isoforms (α1 , β1 , phospholemman/FXYD1). Thus, BFR-training enhances performance and K+ regulation during intense exercise, which may be a result of adaptations in anti-oxidant function, blood flow and Na+ ,K+ -ATPase-isoform abundance at the fibre-type level. ABSTRACT We examined whether blood flow restriction (BFR) augments training-induced improvements in K+ regulation and performance during intense exercise in men, and also whether these adaptations are associated with an altered muscle anti-oxidant function, blood flow and/or with fibre type-dependent changes in Na+ ,K+ -ATPase-isoform abundance. Ten recreationally-active men (25 ± 4 years, 49.7 ± 5.3 mL kg-1 min-1 ) performed 6 weeks of interval cycling, where one leg trained without BFR (control; CON-leg) and the other trained with BFR (BFR-leg, pressure: ∼180 mmHg). Before and after training, femoral arterial and venous K+ concentrations and artery blood flow were measured during single-leg knee-extensor exercise at 25% (Ex1) and 90% of thigh incremental peak power (Ex2) with i.v. infusion of N-acetylcysteine (NAC) or placebo (saline) and a resting muscle biopsy was collected. After training, performance increased more in BFR-leg (23%) than in CON-leg (12%, P < 0.05), whereas K+ release during Ex2 was attenuated only from BFR-leg (P < 0.05). The muscle GSH:GSSG ratio at rest and blood flow during exercise was higher in BFR-leg than in CON-leg after training (P < 0.05). After training, NAC increased resting muscle GSH concentration and thigh net K+ release during Ex2 only in BFR-leg (P < 0.05), whereas the abundance of Na+ ,K+ -ATPase-isoform α1 in type II (51%), β1 in type I (33%), and FXYD1 in type I (108%) and type II (60%) fibres was higher in BFR-leg than in CON-leg (P < 0.05). Thus, training with BFR elicited greater improvements in performance and reduced thigh K+ release during intense exercise, which were associated with adaptations in muscle anti-oxidant function, blood flow and Na+ ,K+ -ATPase-isoform abundance at the fibre-type level.
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Affiliation(s)
- Danny Christiansen
- Section of Integrative Physiology, Department of Nutrition, Exercise and Sports (NEXS), University of Copenhagen, Copenhagen, Denmark.,Institute for Health and Sport (IHES), Victoria University, Melbourne, VIC, Australia
| | - Kasper H Eibye
- Section of Integrative Physiology, Department of Nutrition, Exercise and Sports (NEXS), University of Copenhagen, Copenhagen, Denmark
| | - Villads Rasmussen
- Section of Integrative Physiology, Department of Nutrition, Exercise and Sports (NEXS), University of Copenhagen, Copenhagen, Denmark
| | - Hans M Voldbye
- Section of Integrative Physiology, Department of Nutrition, Exercise and Sports (NEXS), University of Copenhagen, Copenhagen, Denmark
| | - Martin Thomassen
- Section of Integrative Physiology, Department of Nutrition, Exercise and Sports (NEXS), University of Copenhagen, Copenhagen, Denmark
| | - Michael Nyberg
- Section of Integrative Physiology, Department of Nutrition, Exercise and Sports (NEXS), University of Copenhagen, Copenhagen, Denmark
| | - Thomas G P Gunnarsson
- Section of Integrative Physiology, Department of Nutrition, Exercise and Sports (NEXS), University of Copenhagen, Copenhagen, Denmark
| | - Casper Skovgaard
- Section of Integrative Physiology, Department of Nutrition, Exercise and Sports (NEXS), University of Copenhagen, Copenhagen, Denmark
| | - Mads S Lindskrog
- Section of Integrative Physiology, Department of Nutrition, Exercise and Sports (NEXS), University of Copenhagen, Copenhagen, Denmark
| | - David J Bishop
- Institute for Health and Sport (IHES), Victoria University, Melbourne, VIC, Australia.,School of Medical and Health Sciences, Edith Cowan University, Perth, WA, Australia
| | - Morten Hostrup
- Section of Integrative Physiology, Department of Nutrition, Exercise and Sports (NEXS), University of Copenhagen, Copenhagen, Denmark
| | - Jens Bangsbo
- Section of Integrative Physiology, Department of Nutrition, Exercise and Sports (NEXS), University of Copenhagen, Copenhagen, Denmark
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24
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Christiansen D. Molecular stressors underlying exercise training-induced improvements in K + regulation during exercise and Na + ,K + -ATPase adaptation in human skeletal muscle. Acta Physiol (Oxf) 2019; 225:e13196. [PMID: 30288889 DOI: 10.1111/apha.13196] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Revised: 09/12/2018] [Accepted: 09/28/2018] [Indexed: 12/28/2022]
Abstract
Despite substantial progress made towards a better understanding of the importance of skeletal muscle K+ regulation for human physical function and its association with several disease states (eg type-II diabetes and hypertension), the molecular basis underpinning adaptations in K+ regulation to various stimuli, including exercise training, remains inadequately explored in humans. In this review, the molecular mechanisms essential for enhancing skeletal muscle K+ regulation and its key determinants, including Na+ ,K+ -ATPase function and expression, by exercise training are examined. Special attention is paid to the following molecular stressors and signaling proteins: oxygenation, redox balance, hypoxia, reactive oxygen species, antioxidant function, Na+ ,K+ , and Ca2+ concentrations, anaerobic ATP turnover, AMPK, lactate, and mRNA expression. On this basis, an update on the effects of different types of exercise training on K+ regulation in humans is provided, focusing on recent discoveries about the muscle fibre-type-dependent regulation of Na+ ,K+ -ATPase-isoform expression. Furthermore, with special emphasis on blood-flow-restricted exercise as an exemplary model to modulate the key molecular mechanisms identified, it is discussed how training interventions may be designed to maximize improvements in K+ regulation in humans. The novel insights gained from this review may help us to better understand how exercise training and other strategies, such as pharmacological interventions, may be best designed to enhance K+ regulation and thus the physical function in humans.
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Affiliation(s)
- Danny Christiansen
- Department of Nutrition, Exercise and Sports (NEXS) University of Copenhagen Copenhagen Denmark
- Institute for Health and Sport (IHES) Victoria University Melbourne Victoria Australia
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25
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The Na/K-ATPase Signaling: From Specific Ligands to General Reactive Oxygen Species. Int J Mol Sci 2018; 19:ijms19092600. [PMID: 30200500 PMCID: PMC6163532 DOI: 10.3390/ijms19092600] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Revised: 08/10/2018] [Accepted: 08/28/2018] [Indexed: 12/16/2022] Open
Abstract
The signaling function of the Na/K-ATPase has been established for 20 years and is widely accepted in the field, with many excellent reports and reviews not cited here. Even though there is debate about the underlying mechanism, the signaling function is unquestioned. This short review looks back at the evolution of Na/K-ATPase signaling, from stimulation by cardiotonic steroids (also known as digitalis-like substances) as specific ligands to stimulation by reactive oxygen species (ROS) in general. The interplay of cardiotonic steroids and ROS in Na/K-ATPase signaling forms a positive-feedback oxidant amplification loop that has been implicated in some pathophysiological conditions.
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26
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Guo J, Kim HS, Asmis R, Ludueña RF. Interactions of β tubulin isotypes with glutathione in differentiated neuroblastoma cells subject to oxidative stress. Cytoskeleton (Hoboken) 2018; 75:283-289. [PMID: 29663696 DOI: 10.1002/cm.21447] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Revised: 03/16/2018] [Accepted: 04/11/2018] [Indexed: 01/23/2023]
Abstract
Microtubules are a major component of the neuronal cytoskeleton. Tubulin, the subunit protein of microtubules, is an α/β heterodimer. Both α and β exist as families of isotypes, whose members are encoded by different genes and have different amino acid sequences. The βII and βIII isotypes are very prominent in the nervous system. Our previous work has suggested that βII may play a role in neuronal differentiation, but the role of βIII in neurons is not well understood. In the work reported here, we examined the roles of the different β-tubulin isotypes in response to glutamate/glycine treatment, and found that both βII and βIII bind to glutathione in the presence of ROS, especially βIII. In contrast, βI did not bind to glutathione. Our results suggest that βII and βIII, but especially βIII, may play an important role in the response of neuronal cells to stress. In view of the high levels of βII and βIII expressed in the nervous system it is conceivable that these tubulin isotypes may use their sulfhydryl groups to scavenge ROS and protect neuronal cells against oxidative stress.
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Affiliation(s)
- Jiayan Guo
- Department of Biochemistry, University of Texas Health Science Center at San Antonio, San Antonio, Texas 72290-3900
| | - Hong Seok Kim
- Department of Molecular Medicine, College of Medicine, Inha University, Incheon 22212, Republic of Korea
| | - Reto Asmis
- Clinical Laboratory Science, University of Texas Health Science Center at San Antonio, San Antonio, Texas 72290-3900
| | - Richard F Ludueña
- Department of Biochemistry, University of Texas Health Science Center at San Antonio, San Antonio, Texas 72290-3900
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27
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Liu J, Lilly MN, Shapiro JI. Targeting Na/K-ATPase Signaling: A New Approach to Control Oxidative Stress. Curr Pharm Des 2018; 24:359-364. [PMID: 29318961 PMCID: PMC6052765 DOI: 10.2174/1381612824666180110101052] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2017] [Revised: 12/27/2017] [Accepted: 01/04/2017] [Indexed: 01/13/2023]
Abstract
Renal and cardiac function are greatly affected by chronic oxidative stress which can cause many pathophysiological states. The Na/K-ATPase is well-described as an ion pumping enzyme involved in maintaining cellular ion homeostasis; however, in the past two decades, extensive research has been done to understand the signaling function of the Na/K-ATPase and determine its role in physiological and pathophysiological states. Our lab has shown that the Na/K-ATPase signaling cascade can function as an amplifier of reactive oxygen species (ROS) which can be initiated by cardiotonic steroids or increases in ROS. Regulation of systemic oxidative stress by targeting Na/K-ATPase signaling mediated oxidant amplification improves 5/6th partial nephrectomy (PNx) mediated uremic cardiomyopathy, renal sodium handling, as well as ameliorates adipogenesis. This review will present this new concept of Na/K-ATPase signaling mediated oxidant amplification loop and its clinic implication.
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Affiliation(s)
- Jiang Liu
- Dept. of Biomedical Sciences, Joan C. Edwards School of Medicine, Marshall University, Huntington, WV
| | - Megan N. Lilly
- Dept. of Biomedical Sciences, Joan C. Edwards School of Medicine, Marshall University, Huntington, WV
| | - Joseph I. Shapiro
- Dept. of Medicine, Joan C. Edwards School of Medicine, Marshall University, Huntington, WV
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28
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Arystarkhova E, Bouley R, Liu YB, Sweadner KJ. Impaired AQP2 trafficking in Fxyd1 knockout mice: A role for FXYD1 in regulated vesicular transport. PLoS One 2017; 12:e0188006. [PMID: 29155857 PMCID: PMC5695786 DOI: 10.1371/journal.pone.0188006] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Accepted: 10/30/2017] [Indexed: 01/08/2023] Open
Abstract
The final adjustment of urine volume occurs in the inner medullary collecting duct (IMCD), chiefly mediated by the water channel aquaporin 2 (AQP2). With vasopressin stimulation, AQP2 accumulation in the apical plasma membrane of principal cells allows water reabsorption from the lumen. We report that FXYD1 (phospholemman), better known as a regulator of Na,K-ATPase, has a role in AQP2 trafficking. Daytime urine of Fxyd1 knockout mice was more dilute than WT despite similar serum vasopressin, but both genotypes could concentrate urine during water deprivation. FXYD1 was found in IMCD. In WT mice, phosphorylated FXYD1 was detected intracellularly, and vasopressin induced its dephosphorylation. We tested the hypothesis that the dilute urine in knockouts was caused by alteration of AQP2 trafficking. In WT mice at baseline, FXYD1 and AQP2 were not strongly co-localized, but elevation of vasopressin produced translocation of both FXYD1 and AQP2 to the apical plasma membrane. In kidney slices, baseline AQP2 distribution was more scattered in the Fxyd1 knockout than in WT. Apical recruitment of AQP2 occurred in vasopressin-treated Fxyd1 knockout slices, but upon vasopressin washout, there was more rapid reversal of apical AQP2 localization and more heterogeneous cytoplasmic distribution of AQP2. Notably, in sucrose gradients, AQP2 was present in a detergent-resistant membrane domain that had lower sedimentation density in the knockout than in WT, and vasopressin treatment normalized its density. We propose that FXYD1 plays a role in regulating AQP2 retention in apical membrane, and that this involves transfers between raft-like membrane domains in endosomes and plasma membranes.
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Affiliation(s)
- Elena Arystarkhova
- Laboratory of Membrane Biology, Dept. of Neurosurgery, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, Unites States of America
- * E-mail: (EA); (KJS)
| | - Richard Bouley
- Center for Systems Biology, Program in Membrane Biology and Division of Nephrology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
| | - Yi Bessie Liu
- Laboratory of Membrane Biology, Dept. of Neurosurgery, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, Unites States of America
| | - Kathleen J. Sweadner
- Laboratory of Membrane Biology, Dept. of Neurosurgery, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, Unites States of America
- * E-mail: (EA); (KJS)
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Blaustein MP. How does pressure overload cause cardiac hypertrophy and dysfunction? High-ouabain affinity cardiac Na + pumps are crucial. Am J Physiol Heart Circ Physiol 2017; 313:H919-H930. [PMID: 28733446 PMCID: PMC5792198 DOI: 10.1152/ajpheart.00131.2017] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Revised: 07/18/2017] [Accepted: 07/18/2017] [Indexed: 12/17/2022]
Abstract
Left ventricular hypertrophy is frequently observed in hypertensive patients and is believed to be due to the pressure overload and cardiomyocyte stretch. Three recent reports on mice with genetically engineered Na+ pumps, however, have demonstrated that cardiac ouabain-sensitive α2-Na+ pumps play a key role in the pathogenesis of transaortic constriction-induced hypertrophy. Hypertrophy was delayed/attenuated in mice with mutant, ouabain-resistant α2-Na+ pumps and in mice with cardiac-selective knockout or transgenic overexpression of α2-Na+ pumps. The latter, seemingly paradoxical, findings can be explained by comparing the numbers of available (ouabain-free) high-affinity (α2) ouabain-binding sites in wild-type, knockout, and transgenic hearts. Conversely, hypertrophy was accelerated in α2-ouabain-resistant (R) mice in which the normally ouabain-resistant α1-Na+ pumps were mutated to an ouabain-sensitive (S) form (α1S/Sα2R/R or "SWAP" vs. wild-type or α1R/R α2S/S mice). Furthermore, transaortic constriction-induced hypertrophy in SWAP mice was prevented/reversed by immunoneutralizing circulating endogenous ouabain (EO). These findings show that EO and its receptor, ouabain-sensitive α2, are critical factors in pressure overload-induced cardiac hypertrophy. This complements reports linking elevated plasma EO to hypertension, cardiac hypertrophy, and failure in humans and elucidates the underappreciated role of the EO-Na+ pump pathway in cardiovascular disease.
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Affiliation(s)
- Mordecai P. Blaustein
- Departments of Physiology and Medicine, University of Maryland School of Medicine, Baltimore, Maryland
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30
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Bubb KJ, Birgisdottir AB, Tang O, Hansen T, Figtree GA. Redox modification of caveolar proteins in the cardiovascular system- role in cellular signalling and disease. Free Radic Biol Med 2017; 109:61-74. [PMID: 28188926 DOI: 10.1016/j.freeradbiomed.2017.02.012] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Revised: 01/18/2017] [Accepted: 02/05/2017] [Indexed: 02/07/2023]
Abstract
Rapid and coordinated release of a variety of reactive oxygen species (ROS) such as superoxide (O2.-), hydrogen peroxide (H2O2) and peroxynitrite, in specific microdomains, play a crucial role in cell signalling in the cardiovascular system. These reactions are mediated by reversible and functional modifications of a wide variety of key proteins. Dysregulation of this oxidative signalling occurs in almost all forms of cardiovascular disease (CVD), including at the very early phases. Despite the heavily publicized failure of "antioxidants" to improve CVD progression, pharmacotherapies such as those targeting the renin-angiotensin system, or statins, exert at least part of their large clinical benefit via modulating cellular redox signalling. Over 250 proteins, including receptors, ion channels and pumps, and signalling proteins are found in the caveolae. An increasing proportion of these are being recognized as redox regulated-proteins, that reside in the immediate vicinity of the two major cellular sources of ROS, nicotinamide adenine dinucleotide phosphate oxidase (Nox) and uncoupled endothelial nitric oxide synthase (eNOS). This review focuses on what is known about redox signalling within the caveolae, as well as endogenous protective mechanisms utilized by the cell, and new approaches to targeting dysregulated redox signalling in the caveolae as a therapeutic strategy in CVD.
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Affiliation(s)
- Kristen J Bubb
- Kolling Institute of Medical Research, University of Sydney and Cardiology Department, Royal North Shore Hospital, St Leonards, NSW 2065, Australia
| | - Asa Birna Birgisdottir
- Kolling Institute of Medical Research, University of Sydney and Cardiology Department, Royal North Shore Hospital, St Leonards, NSW 2065, Australia; Department of Cardiothoracic and Vascular Surgery, Heart and Lung Clinic, University Hospital of North Norway, Tromsø, Norway
| | - Owen Tang
- Kolling Institute of Medical Research, University of Sydney and Cardiology Department, Royal North Shore Hospital, St Leonards, NSW 2065, Australia
| | - Thomas Hansen
- Kolling Institute of Medical Research, University of Sydney and Cardiology Department, Royal North Shore Hospital, St Leonards, NSW 2065, Australia
| | - Gemma A Figtree
- Kolling Institute of Medical Research, University of Sydney and Cardiology Department, Royal North Shore Hospital, St Leonards, NSW 2065, Australia.
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31
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Wang X, Liu J, Drummond CA, Shapiro JI. Sodium potassium adenosine triphosphatase (Na/K-ATPase) as a therapeutic target for uremic cardiomyopathy. Expert Opin Ther Targets 2017; 21:531-541. [PMID: 28338377 PMCID: PMC5590225 DOI: 10.1080/14728222.2017.1311864] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Accepted: 03/23/2017] [Indexed: 12/30/2022]
Abstract
INTRODUCTION Clinically, patients with significant reductions in renal function present with cardiovascular dysfunction typically termed, uremic cardiomyopathy. It is a progressive series of cardiac pathophysiological changes, including left ventricular diastolic dysfunction and hypertrophy (LVH) which sometimes progress to left ventricular dilation (LVD) and systolic dysfunction in the setting of chronic kidney disease (CKD). Uremic cardiomyopathy is almost ubiquitous in patients afflicted with end stage renal disease (ESRD). Areas covered: This article reviews recent epidemiology, pathophysiology of uremic cardiomyopathy and provide a board overview of Na/K-ATPase research with detailed discussion on the mechanisms of Na/K-ATPase/Src/ROS amplification loop. We also present clinical and preclinical evidences as well as molecular mechanism of this amplification loop in the development of uremic cardiomyopathy. A potential therapeutic peptide that targets on this loop is discussed. Expert opinion: Current clinical treatment for uremic cardiomyopathy remains disappointing. Targeting the ROS amplification loop mediated by the Na/K-ATPase signaling function may provide a novel therapeutic target for uremic cardiomyopathy and related diseases. Additional studies of Na/K-ATPase and other strategies that regulate this loop will lead to new therapeutics.
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Affiliation(s)
- Xiaoliang Wang
- a Joan C Edwards School of Medicine at Marshall University , Huntington , WV , United States
- b University of Toledo College of Medicine and Life Sciences , Toledo , OH , United States
| | - Jiang Liu
- a Joan C Edwards School of Medicine at Marshall University , Huntington , WV , United States
| | - Christopher A Drummond
- b University of Toledo College of Medicine and Life Sciences , Toledo , OH , United States
| | - Joseph I Shapiro
- a Joan C Edwards School of Medicine at Marshall University , Huntington , WV , United States
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Srikanthan K, Shapiro JI, Sodhi K. The Role of Na/K-ATPase Signaling in Oxidative Stress Related to Obesity and Cardiovascular Disease. Molecules 2016; 21:molecules21091172. [PMID: 27598118 PMCID: PMC5642908 DOI: 10.3390/molecules21091172] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Revised: 08/26/2016] [Accepted: 09/01/2016] [Indexed: 12/16/2022] Open
Abstract
Na/K-ATPase has been extensively studied for its ion pumping function, but, in the past several decades, has been identified as a scaffolding and signaling protein. Initially it was found that cardiotonic steroids (CTS) mediate signal transduction through the Na/K-ATPase and result in the generation of reactive oxygen species (ROS), which are also capable of initiating the signal cascade. However, in recent years, this Na/K-ATPase/ROS amplification loop has demonstrated significance in oxidative stress related disease states, including obesity, atherosclerosis, heart failure, uremic cardiomyopathy, and hypertension. The discovery of this novel oxidative stress signaling pathway, holds significant therapeutic potential for the aforementioned conditions and others that are rooted in ROS.
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Affiliation(s)
- Krithika Srikanthan
- Department of Medicine, Joan C. Edwards School of Medicine, Marshall University, Huntington, WV 25701, USA.
| | - Joseph I Shapiro
- Department of Medicine, Joan C. Edwards School of Medicine, Marshall University, Huntington, WV 25701, USA.
| | - Komal Sodhi
- Department of Surgery, Joan C. Edwards School of Medicine, Marshall University, Huntington, WV 25701, USA.
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Stanley CM, Gagnon DG, Bernal A, Meyer DJ, Rosenthal JJ, Artigas P. Importance of the Voltage Dependence of Cardiac Na/K ATPase Isozymes. Biophys J 2016; 109:1852-62. [PMID: 26536262 DOI: 10.1016/j.bpj.2015.09.015] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Revised: 08/11/2015] [Accepted: 09/10/2015] [Indexed: 11/25/2022] Open
Abstract
Cardiac cells express more than one isoform of the Na, K-ATPase (NKA), the heteromeric enzyme that creates the Na(+) and K(+) gradients across the plasmalemma. Cardiac isozymes contain one catalytic α-subunit isoform (α1, α2, or α3) associated with an auxiliary β-subunit isoform (β1 or β2). Past studies using biochemical approaches have revealed minor kinetic differences between isozymes formed by different α-β isoform combinations; these results make it difficult to understand the physiological requirement for multiple isoforms. In intact cells, however, NKA enzymes operate in a more complex environment, which includes a substantial transmembrane potential. We evaluated the voltage dependence of human cardiac NKA isozymes expressed in Xenopus oocytes, and of native NKA isozymes in rat ventricular myocytes, using normal mammalian physiological concentrations of Na(+)o and K(+)o. We demonstrate that although α1 and α3 pumps are functional at all physiologically relevant voltages, α2β1 pumps and α2β2 pumps are inhibited by ∼75% and ∼95%, respectively, at resting membrane potentials, and only activate appreciably upon depolarization. Furthermore, phospholemman (FXYD1) inhibits pump function without significantly altering the pump's voltage dependence. Our observations provide a simple explanation for the physiological relevance of the α2 subunit (∼20% of total α subunits in rat ventricle): they act as a reserve and are recruited into action for extra pumping during the long-lasting cardiac action potential, where most of the Na(+) entry occurs. This strong voltage dependence of α2 pumps also helps explain how cardiotonic steroids, which block NKA pumps, can be a beneficial treatment for heart failure: by only inhibiting the α2 pumps, they selectively reduce NKA activity during the cardiac action potential, leading to an increase in systolic Ca(2+), due to reduced extrusion through the Na/Ca exchanger, without affecting resting Na(+) and Ca(2+) concentrations.
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Affiliation(s)
- Christopher M Stanley
- Department of Cell Physiology and Molecular Biophysics, Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, Texas
| | - Dominique G Gagnon
- Department of Cell Physiology and Molecular Biophysics, Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, Texas; Department of Physics, Texas Tech University, Lubbock, Texas
| | - Adam Bernal
- Department of Cell Physiology and Molecular Biophysics, Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, Texas
| | - Dylan J Meyer
- Department of Cell Physiology and Molecular Biophysics, Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, Texas
| | - Joshua J Rosenthal
- Universidad de Puerto Rico, Recinto de Ciencias Médicas, Instituto de Neurobiología, San Juan, Puerto Rico
| | - Pablo Artigas
- Department of Cell Physiology and Molecular Biophysics, Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, Texas.
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Bogdanova A, Petrushanko IY, Hernansanz-Agustín P, Martínez-Ruiz A. "Oxygen Sensing" by Na,K-ATPase: These Miraculous Thiols. Front Physiol 2016; 7:314. [PMID: 27531981 PMCID: PMC4970491 DOI: 10.3389/fphys.2016.00314] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2016] [Accepted: 07/12/2016] [Indexed: 12/16/2022] Open
Abstract
Control over the Na,K-ATPase function plays a central role in adaptation of the organisms to hypoxic and anoxic conditions. As the enzyme itself does not possess O2 binding sites its "oxygen-sensitivity" is mediated by a variety of redox-sensitive modifications including S-glutathionylation, S-nitrosylation, and redox-sensitive phosphorylation. This is an overview of the current knowledge on the plethora of molecular mechanisms tuning the activity of the ATP-consuming Na,K-ATPase to the cellular metabolic activity. Recent findings suggest that oxygen-derived free radicals and H2O2, NO, and oxidized glutathione are the signaling messengers that make the Na,K-ATPase "oxygen-sensitive." This very ancient signaling pathway targeting thiols of all three subunits of the Na,K-ATPase as well as redox-sensitive kinases sustains the enzyme activity at the "optimal" level avoiding terminal ATP depletion and maintaining the transmembrane ion gradients in cells of anoxia-tolerant species. We acknowledge the complexity of the underlying processes as we characterize the sources of reactive oxygen and nitrogen species production in hypoxic cells, and identify their targets, the reactive thiol groups which, upon modification, impact the enzyme activity. Structured accordingly, this review presents a summary on (i) the sources of free radical production in hypoxic cells, (ii) localization of regulatory thiols within the Na,K-ATPase and the role reversible thiol modifications play in responses of the enzyme to a variety of stimuli (hypoxia, receptors' activation) (iii) redox-sensitive regulatory phosphorylation, and (iv) the role of fine modulation of the Na,K-ATPase function in survival success under hypoxic conditions. The co-authors attempted to cover all the contradictions and standing hypotheses in the field and propose the possible future developments in this dynamic area of research, the importance of which is hard to overestimate. Better understanding of the processes underlying successful adaptation strategies will make it possible to harness them and use for treatment of patients with stroke and myocardial infarction, sleep apnoea and high altitude pulmonary oedema, and those undergoing surgical interventions associated with the interruption of blood perfusion.
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Affiliation(s)
- Anna Bogdanova
- Institute of Veterinary Physiology, Vetsuisse Faculty and the Zurich Center for Integrative Human Physiology (ZIHP), University of ZurichZurich, Switzerland
| | - Irina Y. Petrushanko
- Engelhardt Institute of Molecular Biology, Russian Academy of SciencesMoscow, Russia
| | - Pablo Hernansanz-Agustín
- Servicio de Inmunología, Instituto de Investigación Sanitaria Princesa (IIS-IP), Hospital Universitario de La PrincesaMadrid, Spain
- Departamento de Bioquímica, Universidad Autónoma de MadridMadrid, Spain
| | - Antonio Martínez-Ruiz
- Servicio de Inmunología, Instituto de Investigación Sanitaria Princesa (IIS-IP), Hospital Universitario de La PrincesaMadrid, Spain
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Blaustein MP, Chen L, Hamlyn JM, Leenen FHH, Lingrel JB, Wier WG, Zhang J. Pivotal role of α2 Na + pumps and their high affinity ouabain binding site in cardiovascular health and disease. J Physiol 2016; 594:6079-6103. [PMID: 27350568 DOI: 10.1113/jp272419] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Accepted: 06/18/2016] [Indexed: 12/13/2022] Open
Abstract
Reduced smooth muscle (SM)-specific α2 Na+ pump expression elevates basal blood pressure (BP) and increases BP sensitivity to angiotensin II (Ang II) and dietary NaCl, whilst SM-α2 overexpression lowers basal BP and decreases Ang II/salt sensitivity. Prolonged ouabain infusion induces hypertension in rodents, and ouabain-resistant mutation of the α2 ouabain binding site (α2R/R mice) confers resistance to several forms of hypertension. Pressure overload-induced heart hypertrophy and failure are attenuated in cardio-specific α2 knockout, cardio-specific α2 overexpression and α2R/R mice. We propose a unifying hypothesis that reconciles these apparently disparate findings: brain mechanisms, activated by Ang II and high NaCl, regulate sympathetic drive and a novel neurohumoral pathway mediated by both brain and circulating endogenous ouabain (EO). Circulating EO modulates ouabain-sensitive α2 Na+ pump activity and Ca2+ transporter expression and, via Na+ /Ca2+ exchange, Ca2+ homeostasis. This regulates sensitivity to sympathetic activity, Ca2+ signalling and arterial and cardiac contraction.
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Affiliation(s)
- Mordecai P Blaustein
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA. .,Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, 21201, USA.
| | - Ling Chen
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA.,Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - John M Hamlyn
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - Frans H H Leenen
- Hypertension Unit, University of Ottawa Heart Institute, Ottawa, ON, Canada, K1Y 4W7
| | - Jerry B Lingrel
- Department of Molecular Genetics, Biochemistry and Microbiology, University of Cincinnati College of Medicine, Cincinnati, OH, 45267-0524, USA
| | - W Gil Wier
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - Jin Zhang
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
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Pirkmajer S, Chibalin AV. Na,K-ATPase regulation in skeletal muscle. Am J Physiol Endocrinol Metab 2016; 311:E1-E31. [PMID: 27166285 DOI: 10.1152/ajpendo.00539.2015] [Citation(s) in RCA: 70] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/31/2015] [Accepted: 05/02/2016] [Indexed: 12/17/2022]
Abstract
Skeletal muscle contains one of the largest and the most dynamic pools of Na,K-ATPase (NKA) in the body. Under resting conditions, NKA in skeletal muscle operates at only a fraction of maximal pumping capacity, but it can be markedly activated when demands for ion transport increase, such as during exercise or following food intake. Given the size, capacity, and dynamic range of the NKA pool in skeletal muscle, its tight regulation is essential to maintain whole body homeostasis as well as muscle function. To reconcile functional needs of systemic homeostasis with those of skeletal muscle, NKA is regulated in a coordinated manner by extrinsic stimuli, such as hormones and nerve-derived factors, as well as by local stimuli arising in skeletal muscle fibers, such as contractions and muscle energy status. These stimuli regulate NKA acutely by controlling its enzymatic activity and/or its distribution between the plasma membrane and the intracellular storage compartment. They also regulate NKA chronically by controlling NKA gene expression, thus determining total NKA content in skeletal muscle and its maximal pumping capacity. This review focuses on molecular mechanisms that underlie regulation of NKA in skeletal muscle by major extrinsic and local stimuli. Special emphasis is given to stimuli and mechanisms linking regulation of NKA and energy metabolism in skeletal muscle, such as insulin and the energy-sensing AMP-activated protein kinase. Finally, the recently uncovered roles for glutathionylation, nitric oxide, and extracellular K(+) in the regulation of NKA in skeletal muscle are highlighted.
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Affiliation(s)
- Sergej Pirkmajer
- Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia; and
| | - Alexander V Chibalin
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
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Shah PT, Martin R, Yan Y, Shapiro JI, Liu J. Carbonylation Modification Regulates Na/K-ATPase Signaling and Salt Sensitivity: A Review and a Hypothesis. Front Physiol 2016; 7:256. [PMID: 27445847 PMCID: PMC4923243 DOI: 10.3389/fphys.2016.00256] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Accepted: 06/11/2016] [Indexed: 01/01/2023] Open
Abstract
Na/K-ATPase signaling has been implicated in different physiological and pathophysiological conditions. Accumulating evidence indicates that oxidative stress not only regulates the Na/K-ATPase enzymatic activity, but also regulates its signaling and other functions. While cardiotonic steroids (CTS)-induced increase in reactive oxygen species (ROS) generation is an intermediate step in CTS-mediated Na/K-ATPase signaling, increase in ROS alone also stimulates Na/K-ATPase signaling. Based on literature and our observations, we hypothesize that ROS have biphasic effects on Na/K-ATPase signaling, transcellular sodium transport, and urinary sodium excretion. Oxidative modulation, in particular site specific carbonylation of the Na/K-ATPase α1 subunit, is a critical step in proximal tubular Na/K-ATPase signaling and decreased transcellular sodium transport leading to increases in urinary sodium excretion. However, once this system is overstimulated, the signaling, and associated changes in sodium excretion are blunted. This review aims to evaluate ROS-mediated carbonylation of the Na/K-ATPase, and its potential role in the regulation of pump signaling and sodium reabsorption in the renal proximal tubule (RPT).
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Affiliation(s)
- Preeya T Shah
- Department of Pharmacology, Physiology and Toxicology, Joan C. Edwards School of Medicine, Marshall University Huntington, WV, USA
| | - Rebecca Martin
- Department of Pharmacology, Physiology and Toxicology, Joan C. Edwards School of Medicine, Marshall University Huntington, WV, USA
| | - Yanling Yan
- Department of Pharmacology, Physiology and Toxicology, Joan C. Edwards School of Medicine, Marshall University Huntington, WV, USA
| | - Joseph I Shapiro
- Department of Pharmacology, Physiology and Toxicology, Joan C. Edwards School of Medicine, Marshall University Huntington, WV, USA
| | - Jiang Liu
- Department of Pharmacology, Physiology and Toxicology, Joan C. Edwards School of Medicine, Marshall University Huntington, WV, USA
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Yang WK, Kang CK, Hsu AD, Lin CH, Lee TH. Different Modulatory Mechanisms of Renal FXYD12 for Na(+)-K(+)-ATPase between Two Closely Related Medakas upon Salinity Challenge. Int J Biol Sci 2016; 12:730-45. [PMID: 27194950 PMCID: PMC4870716 DOI: 10.7150/ijbs.15066] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2016] [Accepted: 03/21/2016] [Indexed: 12/02/2022] Open
Abstract
Upon salinity challenge, the Na+-K+-ATPase (NKA) of fish kidney plays a crucial role in maintaining ion and water balance. Moreover, the FXYD protein family was found to be a regulator of NKA. Our preliminary results revealed that fxyd12 was highly expressed in the kidneys of the two closely related euryhaline medaka species (Oryzias dancena and O. latipes) from different natural habitats (brackish water and fresh water). In this study, we investigated the expression and association of renal FXYD12 and NKA α-subunit as well as potential functions of FXYD12 in the two medakas. These findings illustrated and compared the regulatory roles of FXYD12 for NKA in kidneys of the two medakas in response to salinity changes. In this study, at the mRNA and/or protein level, the expression patterns were similar for renal FXYD12 and NKA in the two medakas. However, different patterns of NKA activities and different interaction levels between FXYD12 and NKA were found in the kidneys of these two medakas. The results revealed that different strategies were used in the kidneys of the two medaka species upon salinity challenge. On the other hand, gene knockdown experiments demonstrated that the function of O. dancena FXYD12 allowed maintenance of a high level of NKA activity. The results of the present study indicated that the kidneys of the examined euryhaline medakas originating from brackish water and fresh water exhibited different modulatory mechanisms through which renal FXYD12 enhanced NKA activity to maintain internal homeostasis. Our findings broadened the knowledge of expression and functions of FXYD proteins, the modulators of NKA, in vertebrates.
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Affiliation(s)
- Wen-Kai Yang
- 1. Department of Life Sciences, National Chung Hsing University, Taichung 402, Taiwan
| | - Chao-Kai Kang
- 2. Tainan Hydraulics Laboratory, National Cheng Kung University, Tainan 709, Taiwan
| | - An-Di Hsu
- 1. Department of Life Sciences, National Chung Hsing University, Taichung 402, Taiwan
| | - Chia-Hao Lin
- 3. National Institute for Basic Biology, National Institutes of Natural Sciences, Okazaki, Aichi 444-8787, Japan
| | - Tsung-Han Lee
- 1. Department of Life Sciences, National Chung Hsing University, Taichung 402, Taiwan.; 4. Department of Biological Science and Technology, China Medical University, Taichung 404, Taiwan
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Arystarkhova E. Beneficial Renal and Pancreatic Phenotypes in a Mouse Deficient in FXYD2 Regulatory Subunit of Na,K-ATPase. Front Physiol 2016; 7:88. [PMID: 27014088 PMCID: PMC4779850 DOI: 10.3389/fphys.2016.00088] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Accepted: 02/22/2016] [Indexed: 11/25/2022] Open
Abstract
The fundamental role of Na,K-ATPase in eukaryotic cells calls for complex and efficient regulation of its activity. Besides alterations in gene expression and trafficking, kinetic properties of the pump are modulated by reversible association with single span membrane proteins, the FXYDs. Seven members of the family are expressed in a tissue-specific manner, affecting pump kinetics in all possible permutations. This mini-review focuses on functional properties of FXYD2 studied in transfected cells, and on noteworthy and unexpected phenotypes discovered in a Fxyd2−∕− mouse. FXYD2, the gamma subunit, reduces activity of Na,K-ATPase either by decreasing affinity for Na+, or reducing Vmax. FXYD2 mRNA splicing and editing provide another layer for regulation of Na,K-ATPase. In kidney of knockouts, there was elevated activity for Na,K-ATPase and for NCC and NKCC2 apical sodium transporters. That should lead to sodium retention and hypertension, however, the mice were in sodium balance and normotensive. Adult Fxyd2−∕− mice also exhibited a mild pancreatic phenotype with enhanced glucose tolerance, elevation of circulating insulin, but no insulin resistance. There was an increase in beta cell proliferation and beta cell mass that correlated with activation of the PI3K-Akt pathway. The Fxyd2−∕− mice are thus in a highly desirable state: the animals are resistant to Na+ retention, and showed improved glucose control, i.e., they display favorable metabolic adaptations to protect against development of salt-sensitive hypertension and diabetes. Investigation of the mechanisms of these adaptations in the mouse has the potential to unveil a novel therapeutic FXYD2-dependent strategy.
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Affiliation(s)
- Elena Arystarkhova
- Laboratory of Membrane Biology, Neurosurgery, Massachusetts General Hospital Boston, MA, USA
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40
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Liu CC, Teh R, Mozar CA, Baxter RC, Rasmussen HH. Silencing overexpression of FXYD3 protein in breast cancer cells amplifies effects of doxorubicin and γ-radiation on Na(+)/K(+)-ATPase and cell survival. Breast Cancer Res Treat 2016; 155:203-13. [PMID: 26740212 DOI: 10.1007/s10549-015-3667-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2015] [Accepted: 12/18/2015] [Indexed: 12/01/2022]
Abstract
FXYD3, also known as mammary tumor protein 8, is overexpressed in several common cancers, including in many breast cancers. We examined if such overexpression might protect Na(+)/K(+)-ATPase and cancer cells against the high levels of oxidative stress characteristic of many tumors and often induced by cancer treatments. We measured FXYD3 expression, Na(+)/K(+)-ATPase activity and glutathionylation of the β1 subunit of Na(+)/K(+)-ATPase, a reversible oxidative modification that inhibits the ATPase, in MCF-7 and MDA-MB-468 cells. Expression of FXYD3 was suppressed by transfection with FXYD3 siRNA. A colorimetric end-point assay was used to estimate cell viability. Apoptosis was estimated by caspase 3/7 (DEVDase) activation using a Caspase fluorogenic substrate kit. Expression of FXYD3 in MCF-7 breast cancer cells was ~eightfold and ~twofold higher than in non-cancer MCF-10A cells and MDA-MB-468 cancer cells, respectively. A ~50 % reduction in FXYD3 expression increased glutathionylation of the β1 Na(+)/K(+)-ATPase subunit and reduced Na(+)/K(+)-ATPase activity by ~50 %, consistent with the role of FXYD3 to facilitate reversal of glutathionylation of the β1 subunit of Na(+)/K(+)-ATPase and glutathionylation-induced inhibition of Na(+)/K(+)-ATPase. Treatment of MCF-7 and MDA-MB- 468 cells with doxorubicin or γ-radiation decreased cell viability and induced apoptosis. The treatments upregulated FXYD3 expression in MCF-7 but not in MDA-MB-468 cells and suppression of FXYD3 in MCF-7 but not in MDA-MB-468 cells amplified effects of treatments on Na(+)/K(+)-ATPase activity and treatment-induced cell death and apoptosis. Overexpression of FXYD3 may be a marker of resistance to cancer treatments and a potentially important therapeutic target.
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Affiliation(s)
- Chia-Chi Liu
- North Shore Heart Research Group, Kolling Institute of Medical Research, University of Sydney, Sydney, Australia
| | - Rachel Teh
- North Shore Heart Research Group, Kolling Institute of Medical Research, University of Sydney, Sydney, Australia
| | - Christine A Mozar
- North Shore Heart Research Group, Kolling Institute of Medical Research, University of Sydney, Sydney, Australia
| | - Robert C Baxter
- Hormones and Cancer Laboratories, Kolling Institute of Medical Research, University of Sydney, Sydney, Australia
| | - Helge H Rasmussen
- North Shore Heart Research Group, Kolling Institute of Medical Research, University of Sydney, Sydney, Australia. .,The Department of Cardiology, Royal North Shore Hospital, St Leonards, NSW, 2065, Australia.
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Karimi Galougahi K, Liu CC, Garcia A, Fry NA, Hamilton EJ, Figtree GA, Rasmussen HH. β3-Adrenoceptor activation relieves oxidative inhibition of the cardiac Na+-K+ pump in hyperglycemia induced by insulin receptor blockade. Am J Physiol Cell Physiol 2015; 309:C286-95. [PMID: 26063704 PMCID: PMC4556897 DOI: 10.1152/ajpcell.00071.2015] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Accepted: 06/09/2015] [Indexed: 01/20/2023]
Abstract
Dysregulated nitric oxide (NO)- and superoxide (O2 (·-))-dependent signaling contributes to the pathobiology of diabetes-induced cardiovascular complications. We examined if stimulation of β3-adrenergic receptors (β3-ARs), coupled to endothelial NO synthase (eNOS) activation, relieves oxidative inhibition of eNOS and the Na(+)-K(+) pump induced by hyperglycemia. Hyperglycemia was established in male New Zealand White rabbits by infusion of the insulin receptor antagonist S961 for 7 days. Hyperglycemia increased tissue and blood indexes of oxidative stress. It induced glutathionylation of the Na(+)-K(+) pump β1-subunit in cardiac myocytes, an oxidative modification causing pump inhibition, and reduced the electrogenic pump current in voltage-clamped myocytes. Hyperglycemia also increased glutathionylation of eNOS, which causes its uncoupling, and increased coimmunoprecipitation of cytosolic p47(phox) and membranous p22(phox) NADPH oxidase subunits, consistent with NADPH oxidase activation. Blocking translocation of p47(phox) to p22(phox) with the gp91ds-tat peptide in cardiac myocytes ex vivo abolished the hyperglycemia-induced increase in glutathionylation of the Na(+)-K(+) pump β1-subunit and decrease in pump current. In vivo treatment with the β3-AR agonist CL316243 for 3 days eliminated the increase in indexes of oxidative stress, decreased coimmunoprecipitation of p22(phox) with p47(phox), abolished the hyperglycemia-induced increase in glutathionylation of eNOS and the Na(+)-K(+) pump β1-subunit, and abolished the decrease in pump current. CL316243 also increased coimmunoprecipitation of glutaredoxin-1 with the Na(+)-K(+) pump β1-subunit, which may reflect facilitation of deglutathionylation. In vivo β3-AR activation relieves oxidative inhibition of key cardiac myocyte proteins in hyperglycemia and may be effective in targeting the deleterious cardiac effects of diabetes.
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Affiliation(s)
- Keyvan Karimi Galougahi
- North Shore Heart Research Group, Kolling Institute, University of Sydney, Sydney, Australia; and Department of Cardiology, Royal North Shore Hospital, Sydney, Australia
| | - Chia-Chi Liu
- North Shore Heart Research Group, Kolling Institute, University of Sydney, Sydney, Australia; and
| | - Alvaro Garcia
- North Shore Heart Research Group, Kolling Institute, University of Sydney, Sydney, Australia; and
| | - Natasha A Fry
- North Shore Heart Research Group, Kolling Institute, University of Sydney, Sydney, Australia; and
| | - Elisha J Hamilton
- North Shore Heart Research Group, Kolling Institute, University of Sydney, Sydney, Australia; and
| | - Gemma A Figtree
- North Shore Heart Research Group, Kolling Institute, University of Sydney, Sydney, Australia; and Department of Cardiology, Royal North Shore Hospital, Sydney, Australia
| | - Helge H Rasmussen
- North Shore Heart Research Group, Kolling Institute, University of Sydney, Sydney, Australia; and Department of Cardiology, Royal North Shore Hospital, Sydney, Australia
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Juel C, Hostrup M, Bangsbo J. The effect of exercise and beta2-adrenergic stimulation on glutathionylation and function of the Na,K-ATPase in human skeletal muscle. Physiol Rep 2015; 3:3/8/e12515. [PMID: 26296772 PMCID: PMC4562595 DOI: 10.14814/phy2.12515] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Potassium and sodium displacements across the skeletal muscle membrane during exercise may cause fatigue and are in part controlled by the Na,K-ATPase. Regulation of the Na,K-ATPase is therefore important for muscle functioning. We investigated the effect of oxidative stress (glutathionylation) on Na,K-ATPase activity. Ten male subjects performed three bouts of 4-min submaximal exercise followed by intense exercise to exhaustion with and without beta2-adrenergic stimulation with terbutaline. Muscle biopsies were obtained from m. vastus lateralis at rest (Control samples) and at exhaustion. In vitro glutathionylation reduced (P < 0.05) maximal Na,K-ATPase activity in a dose-dependent manner. Na,K-ATPase α subunits, purified by immunoprecipitation and tested by glutathione (GSH) antibodies, had a basal glutathionylation in Control samples and no further glutathionylation with exercise and beta2-adrenergic stimulation. Immunoprecipitation with an anti-GSH antibody and subsequent immunodetection with β1 antibodies showed approximately 20% glutathionylation in Control samples and further glutathionylation after exercise (to 32%) and beta2-adrenergic stimulation (to 38%, P < 0.05). Combining exercise and beta2-adrenergic stimulation raised the β1 glutathionylation to 45% (P < 0.05). In conclusion, both α and β1 subunits of the Na,K-ATPase were glutathionylated in Control samples, which indicates that the maximal Na,K-ATPase activity is overestimated if based on protein density only. β1 subunits are further glutathionylated by exercise and beta2-adrenergic stimulation. Our data suggest that glutathionylation contributes to the complex regulation of Na,K-ATPase function in human skeletal muscle. Glutathionylation of the Na,K-ATPase may explain reductions in maximal Na,K-ATPase activity after exercise, which may be involved in muscle fatigue.
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Affiliation(s)
- Carsten Juel
- Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Morten Hostrup
- Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Jens Bangsbo
- Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
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Garcia A, Eljack ND, Sani MA, Separovic F, Rasmussen HH, Kopec W, Khandelia H, Cornelius F, Clarke RJ. Membrane accessibility of glutathione. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2015; 1848:2430-6. [PMID: 26232559 DOI: 10.1016/j.bbamem.2015.07.016] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2015] [Revised: 07/23/2015] [Accepted: 07/28/2015] [Indexed: 10/23/2022]
Abstract
Regulation of the ion pumping activity of the Na+,K+-ATPase is crucial to the survival of animal cells. Recent evidence has suggested that the activity of the enzyme could be controlled by glutathionylation of cysteine residue 45 of the β-subunit. Crystal structures so far available indicate that this cysteine is in a transmembrane domain of the protein. Here we have analysed via fluorescence and NMR spectroscopy as well as molecular dynamics simulations whether glutathione is able to penetrate into the interior of a lipid membrane. No evidence for any penetration of glutathione into the membrane was found. Therefore, the most likely mechanism whereby the cysteine residue could become glutathionylated is via a loosening of the α-β subunit association, creating a hydrophilic passageway between them to allow access of glutathione to the cysteine residue. By such a mechanism, glutathionylation of the protein would be expected to anchor the modified cysteine residue in a hydrophilic environment, inhibiting further motion of the β-subunit during the enzyme's catalytic cycle and suppressing enzymatic activity, as has been experimentally observed. The results obtained, therefore, suggest a possible structural mechanism of how the Na+,K+-ATPase could be regulated by glutathione.
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Affiliation(s)
- Alvaro Garcia
- School of Chemistry, University of Sydney, Sydney, New South Wales 2006, Australia
| | - Nasma D Eljack
- School of Chemistry, University of Sydney, Sydney, New South Wales 2006, Australia
| | - Marc-Antoine Sani
- School of Chemistry, Bio21 Institute, University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Frances Separovic
- School of Chemistry, Bio21 Institute, University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Helge H Rasmussen
- Department of Cardiology, Royal North Shore Hospital, Sydney, New South Wales 2065, Australia; Kolling Institute, University of Sydney, Sydney, New South Wales 2065, Australia
| | - Wojciech Kopec
- Center for BioMembrane Physics, University of Southern Denmark, Odense M5230, Denmark
| | - Himanshu Khandelia
- Center for BioMembrane Physics, University of Southern Denmark, Odense M5230, Denmark
| | - Flemming Cornelius
- Department of Biomedicine, University of Aarhus, DK-8000 Aarhus C, Denmark
| | - Ronald J Clarke
- School of Chemistry, University of Sydney, Sydney, New South Wales 2006, Australia.
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Chia KKM, Liu CC, Hamilton EJ, Garcia A, Fry NA, Hannam W, Figtree GA, Rasmussen HH. Stimulation of the cardiac myocyte Na+-K+ pump due to reversal of its constitutive oxidative inhibition. Am J Physiol Cell Physiol 2015; 309:C239-50. [PMID: 26084308 DOI: 10.1152/ajpcell.00392.2014] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Accepted: 06/09/2015] [Indexed: 11/22/2022]
Abstract
Protein kinase C can activate NADPH oxidase and induce glutathionylation of the β1-Na(+)-K(+) pump subunit, inhibiting activity of the catalytic α-subunit. To examine if signaling of nitric oxide-induced soluble guanylyl cyclase (sGC)/cGMP/protein kinase G can cause Na(+)-K(+) pump stimulation by counteracting PKC/NADPH oxidase-dependent inhibition, cardiac myocytes were exposed to ANG II to activate NADPH oxidase and inhibit Na(+)-K(+) pump current (Ip). Coexposure to 3-(5'-hydroxymethyl-2'-furyl)-1-benzylindazole (YC-1) to stimulate sGC prevented the decrease of Ip. Prevention of the decrease was abolished by inhibition of protein phosphatases (PP) 2A but not by inhibition of PP1, and it was reproduced by an activator of PP2A. Consistent with a reciprocal relationship between β1-Na(+)-K(+) pump subunit glutathionylation and pump activity, YC-1 decreased ANG II-induced β1-subunit glutathionylation. The decrease induced by YC-1 was abolished by a PP2A inhibitor. YC-1 decreased phosphorylation of the cytosolic p47(phox) NADPH oxidase subunit and its coimmunoprecipitation with the membranous p22(phox) subunit, and it decreased O2 (·-)-sensitive dihydroethidium fluorescence of myocytes. Addition of recombinant PP2A to myocyte lysate decreased phosphorylation of p47(phox) indicating the subunit could be a substrate for PP2A. The effects of YC-1 to decrease coimmunoprecipitation of p22(phox) and p47(phox) NADPH oxidase subunits and decrease β1-Na(+)-K(+) pump subunit glutathionylation were reproduced by activation of nitric oxide-dependent receptor signaling. We conclude that sGC activation in cardiac myocytes causes a PP2A-dependent decrease in NADPH oxidase activity and a decrease in β1 pump subunit glutathionylation. This could account for pump stimulation with neurohormonal oxidative stress expected in vivo.
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Affiliation(s)
- Karin K M Chia
- North Shore Heart Research Group, Kolling Medical Research Institute, University of Sydney, Sydney, Australia; Royal Brisbane and Women's Hospital, The University of Queensland, Queensland, Australia; and
| | - Chia-Chi Liu
- North Shore Heart Research Group, Kolling Medical Research Institute, University of Sydney, Sydney, Australia
| | - Elisha J Hamilton
- North Shore Heart Research Group, Kolling Medical Research Institute, University of Sydney, Sydney, Australia
| | - Alvaro Garcia
- North Shore Heart Research Group, Kolling Medical Research Institute, University of Sydney, Sydney, Australia
| | - Natasha A Fry
- North Shore Heart Research Group, Kolling Medical Research Institute, University of Sydney, Sydney, Australia
| | - William Hannam
- North Shore Heart Research Group, Kolling Medical Research Institute, University of Sydney, Sydney, Australia
| | - Gemma A Figtree
- North Shore Heart Research Group, Kolling Medical Research Institute, University of Sydney, Sydney, Australia; Department of Cardiology, Royal North Shore Hospital, St. Leonards, Australia
| | - Helge H Rasmussen
- North Shore Heart Research Group, Kolling Medical Research Institute, University of Sydney, Sydney, Australia; Department of Cardiology, Royal North Shore Hospital, St. Leonards, Australia
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Wang F, Cai B, Li KC, Hu XY, Lu YJ, Wang Q, Bao L, Zhang X. FXYD2, a γ subunit of Na⁺, K⁺-ATPase, maintains persistent mechanical allodynia induced by inflammation. Cell Res 2015; 25:318-34. [PMID: 25633594 DOI: 10.1038/cr.2015.12] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2014] [Revised: 10/09/2014] [Accepted: 12/15/2014] [Indexed: 01/08/2023] Open
Abstract
Na⁺, K⁺-ATPase (NKA) is required to generate the resting membrane potential in neurons. Nociceptive afferent neurons express not only the α and β subunits of NKA but also the γ subunit FXYD2. However, the neural function of FXYD2 is unknown. The present study shows that FXYD2 in nociceptive neurons is necessary for maintaining the mechanical allodynia induced by peripheral inflammation. FXYD2 interacted with α1NKA and negatively regulated the NKA activity, depolarizing the membrane potential of nociceptive neurons. Mechanical allodynia initiated in FXYD2-deficient mice was abolished 4 days after inflammation, whereas it persisted for at least 3 weeks in wild-type mice. Importantly, the FXYD2/α1NKA interaction gradually increased after inflammation and peaked on day 4 post inflammation, resulting in reduction of NKA activity, depolarization of neuron membrane and facilitation of excitatory afferent neurotransmission. Thus, the increased FXYD2 activity may be a fundamental mechanism underlying the persistent hypersensitivity to pain induced by inflammation.
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Affiliation(s)
- Feng Wang
- Institute of Neuroscience and State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Bing Cai
- Institute of Neuroscience and State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Kai-Cheng Li
- Institute of Neuroscience and State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Xu-Ye Hu
- Shanghai Clinical Center, Chinese Academy of Sciences/XuHui Central Hospital, Shanghai, China
| | - Ying-Jin Lu
- Institute of Neuroscience and State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Qiong Wang
- State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Lan Bao
- 1] State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China [2] School of Life Science and Technology, ShanghaiTech University, Shanghai 200031, China
| | - Xu Zhang
- 1] Institute of Neuroscience and State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China [2] School of Life Science and Technology, ShanghaiTech University, Shanghai 200031, China
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Wolke C, Bukowska A, Goette A, Lendeckel U. Redox control of cardiac remodeling in atrial fibrillation. Biochim Biophys Acta Gen Subj 2014; 1850:1555-65. [PMID: 25513966 DOI: 10.1016/j.bbagen.2014.12.012] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2014] [Revised: 11/04/2014] [Accepted: 12/09/2014] [Indexed: 01/08/2023]
Abstract
BACKGROUND Atrial fibrillation (AF) is the most common arrhythmia in clinical practice and is a potential cause of thromboembolic events. AF induces significant changes in the electrophysiological properties of atrial myocytes and causes alterations in the structure, metabolism, and function of the atrial tissue. The molecular basis for the development of structural atrial remodeling of fibrillating human atria is still not fully understood. However, increased production of reactive oxygen or nitrogen species (ROS/RNS) and the activation of specific redox-sensitive signaling pathways observed both in patients with and animal models of AF are supposed to contribute to development, progression and self-perpetuation of AF. SCOPE OF REVIEW The present review summarizes the sources and targets of ROS/RNS in the setting of AF and focuses on key redox-sensitive signaling pathways that are implicated in the pathogenesis of AF and function either to aggravate or protect from disease. MAJOR CONCLUSIONS NADPH oxidases and various mitochondrial monooxygenases are major sources of ROS during AF. Besides direct oxidative modification of e.g. ion channels and ion handling proteins that are crucially involved in action potential generation and duration, AF leads to the reversible activation of redox-sensitive signaling pathways mediated by activation of redox-regulated proteins including Nrf2, NF-κB, and CaMKII. Both processes are recognized to contribute to the formation of a substrate for AF and, thus, to increase AF inducibility and duration. GENERAL SIGNIFICANCE AF is a prevalent disease and due to the current demographic developments its socio-economic relevance will further increase. Improving our understanding of the role that ROS and redox-related (patho)-mechanisms play in the development and progression of AF may allow the development of a targeted therapy for AF that surpasses the efficacy of previous general anti-oxidative strategies. This article is part of a Special Issue entitled Redox regulation of differentiation and de-differentiation.
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Affiliation(s)
- Carmen Wolke
- Institute of Medical Biochemistry and Molecular Biology, University Medicine Greifswald, D-17487 Greifswald, Germany
| | - Alicja Bukowska
- EUTRAF Working Group: Molecular Electrophysiology, University Hospital Magdeburg, D-39120 Magdeburg, Germany
| | - Andreas Goette
- EUTRAF Working Group: Molecular Electrophysiology, University Hospital Magdeburg, D-39120 Magdeburg, Germany; Department of Cardiology and Intensive Care Medicine, St. Vincenz-Hospital, D-33098 Paderborn, Germany
| | - Uwe Lendeckel
- Institute of Medical Biochemistry and Molecular Biology, University Medicine Greifswald, D-17487 Greifswald, Germany.
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Abstract
The cardiac phosphoprotein phospholemman (PLM) regulates the cardiac sodium pump, activating the pump when phosphorylated and inhibiting it when palmitoylated. Protein palmitoylation, the reversible attachment of a 16 carbon fatty acid to a cysteine thiol, is catalyzed by the Asp-His-His-Cys (DHHC) motif-containing palmitoyl acyltransferases. The cell surface palmitoyl acyltransferase DHHC5 regulates a growing number of cellular processes, but relatively few DHHC5 substrates have been identified to date. We examined the expression of DHHC isoforms in ventricular muscle and report that DHHC5 is among the most abundantly expressed DHHCs in the heart and localizes to caveolin-enriched cell surface microdomains. DHHC5 coimmunoprecipitates with PLM in ventricular myocytes and transiently transfected cells. Overexpression and silencing experiments indicate that DHHC5 palmitoylates PLM at two juxtamembrane cysteines, C40 and C42, although C40 is the principal palmitoylation site. PLM interaction with and palmitoylation by DHHC5 is independent of the DHHC5 PSD-95/Discs-large/ZO-1 homology (PDZ) binding motif, but requires a ∼ 120 amino acid region of the DHHC5 intracellular C-tail immediately after the fourth transmembrane domain. PLM C42A but not PLM C40A inhibits the Na pump, indicating PLM palmitoylation at C40 but not C42 is required for PLM-mediated inhibition of pump activity. In conclusion, we demonstrate an enzyme-substrate relationship for DHHC5 and PLM and describe a means of substrate recruitment not hitherto described for this acyltransferase. We propose that PLM palmitoylation by DHHC5 promotes phospholipid interactions that inhibit the Na pump.
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48
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Juel C. Oxidative stress (glutathionylation) and Na,K-ATPase activity in rat skeletal muscle. PLoS One 2014; 9:e110514. [PMID: 25310715 PMCID: PMC4195747 DOI: 10.1371/journal.pone.0110514] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Accepted: 09/18/2014] [Indexed: 11/20/2022] Open
Abstract
Background Changes in ion distribution across skeletal muscle membranes during muscle activity affect excitability and may impair force development. These changes are counteracted by the Na,K-ATPase. Regulation of the Na,K-ATPase is therefore important for skeletal muscle function. The present study investigated the presence of oxidative stress (glutathionylation) on the Na,K-ATPase in rat skeletal muscle membranes. Results Immunoprecipitation with an anti-glutathione antibody and subsequent immunodetection of Na,K-ATPase protein subunits demonstrated 9.0±1.3% and 4.1±1.0% glutathionylation of the α isoforms in oxidative and glycolytic skeletal muscle, respectively. In oxidative muscle, 20.0±6.1% of the β1 units were glutathionylated, whereas 14.8±2.8% of the β2-subunits appear to be glutathionylated in glycolytic muscle. Treatment with the reducing agent dithiothreitol (DTT, 1 mM) increased the in vitro maximal Na,K-ATPase activity by 19% (P<0.05) in membranes from glycolytic muscle. Oxidized glutathione (GSSG, 0–10 mM) increased the in vitro glutathionylation level detected with antibodies, and decreased the in vitro maximal Na,K-ATPase activity in a dose-dependent manner, and with a larger effect in oxidative compared to glycolytic skeletal muscle. Conclusion This study demonstrates the existence of basal glutathionylation of both the α and the β units of rat skeletal muscle Na,K-ATPase. In addition, the study suggests a negative correlation between glutathionylation levels and maximal Na,K-ATPase activity. Perspective Glutathionylation likely contributes to the complex regulation of Na,K-ATPase function in skeletal muscle. Especially, glutathionylation induced by oxidative stress may have a role in Na,K-ATPase regulation during prolonged muscle activity.
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Affiliation(s)
- Carsten Juel
- Department of Biology, University of Copenhagen, Copenhagen, Denmark
- * E-mail:
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49
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Yang Y, Jin X, Jiang C. S-glutathionylation of ion channels: insights into the regulation of channel functions, thiol modification crosstalk, and mechanosensing. Antioxid Redox Signal 2014; 20:937-51. [PMID: 23834398 PMCID: PMC3924852 DOI: 10.1089/ars.2013.5483] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
SIGNIFICANCE Ion channels control membrane potential, cellular excitability, and Ca(++) signaling, all of which play essential roles in cellular functions. The regulation of ion channels enables cells to respond to changing environments, and post-translational modification (PTM) is one major regulation mechanism. RECENT ADVANCES Many PTMs (e.g., S-glutathionylation, S-nitrosylation, S-palmitoylation, S-sulfhydration, etc.) targeting the thiol group of cysteine residues have emerged to be essential for ion channels regulation under physiological and pathological conditions. CRITICAL ISSUES Under oxidative stress, S-glutathionylation could be a critical PTM that regulates many molecules. In this review, we discuss S-glutathionylation-mediated structural and functional changes of ion channels. Criteria for testing S-glutathionylation, methods and reagents used in ion channel S-glutathionylation studies, and thiol modification crosstalk, are also covered. Mechanotransduction, and S-glutathionylation of the mechanosensitive KATP channel, are discussed. FUTURE DIRECTIONS Further investigation of the ion channel S-glutathionylation, especially the physiological significance of S-glutathionylation and thiol modification crosstalk, could lead to a better understanding of the thiol modifications in general and the ramifications of such modifications on cellular functions and related diseases.
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Affiliation(s)
- Yang Yang
- 1 Department of Neurology, Yale University School of Medicine , New Haven, Connecticut
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Liu CC, Karimi Galougahi K, Weisbrod RM, Hansen T, Ravaie R, Nunez A, Liu YB, Fry N, Garcia A, Hamilton EJ, Sweadner KJ, Cohen RA, Figtree GA. Oxidative inhibition of the vascular Na+-K+ pump via NADPH oxidase-dependent β1-subunit glutathionylation: implications for angiotensin II-induced vascular dysfunction. Free Radic Biol Med 2013; 65:563-572. [PMID: 23816524 PMCID: PMC4474148 DOI: 10.1016/j.freeradbiomed.2013.06.040] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2013] [Revised: 06/21/2013] [Accepted: 06/21/2013] [Indexed: 02/07/2023]
Abstract
Glutathionylation of the Na(+)-K(+) pump's β1-subunit is a key molecular mechanism of physiological and pathophysiological pump inhibition in cardiac myocytes. Its contribution to Na(+)-K(+) pump regulation in other tissues is unknown, and cannot be assumed given the dependence on specific β-subunit isoform expression and receptor-coupled pathways. As Na(+)-K(+) pump activity is an important determinant of vascular tone through effects on [Ca(2+)]i, we have examined the role of oxidative regulation of the Na(+)-K(+) pump in mediating angiotensin II (Ang II)-induced increases in vascular reactivity. β1-subunit glutathione adducts were present at baseline and increased by exposure to Ang II in rabbit aortic rings, primary rabbit aortic vascular smooth muscle cells (VSMCs), and human arterial segments. In VSMCs, Ang II-induced glutathionylation was associated with marked reduction in Na(+)-K(+)ATPase activity, an effect that was abolished by the NADPH oxidase inhibitory peptide, tat-gp91ds. In aortic segments, Ang II-induced glutathionylation was associated with decreased K(+)-induced vasorelaxation, a validated index of pump activity. Ang II-induced oxidative inhibition of Na(+)-K(+) ATPase and decrease in K(+)-induced relaxation were reversed by preincubation of VSMCs and rings with recombinant FXYD3 protein that is known to facilitate deglutathionylation of β1-subunit. Knock-out of FXYD1 dramatically decreased K(+)-induced relaxation in a mouse model. Attenuation of Ang II signaling in vivo by captopril (8 mg/kg/day for 7 days) decreased superoxide-sensitive DHE levels in the media of rabbit aorta, decreased β1-subunit glutathionylation, and enhanced K(+)-induced vasorelaxation. Ang II inhibits the Na(+)-K(+) pump in VSMCs via NADPH oxidase-dependent glutathionylation of the pump's β1-subunit, and this newly identified signaling pathway may contribute to altered vascular tone. FXYD proteins reduce oxidative inhibition of the Na(+)-K(+) pump and may have an important protective role in the vasculature under conditions of oxidative stress.
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Affiliation(s)
- Chia-Chi Liu
- North Shore Heart Research Group, Kolling Institute of Medical Research, University of Sydney, Australia
| | - Keyvan Karimi Galougahi
- North Shore Heart Research Group, Kolling Institute of Medical Research, University of Sydney, Australia; Department of Cardiology, Royal North Shore Hospital, Sydney, Australia
| | - Robert M Weisbrod
- Vascular Biology Section, Department of Medicine, Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, MA, USA
| | - Thomas Hansen
- North Shore Heart Research Group, Kolling Institute of Medical Research, University of Sydney, Australia
| | - Ramtin Ravaie
- North Shore Heart Research Group, Kolling Institute of Medical Research, University of Sydney, Australia
| | - Andrea Nunez
- North Shore Heart Research Group, Kolling Institute of Medical Research, University of Sydney, Australia
| | - Yi B Liu
- Laboratory Membrane Biology, Massachusetts General Hospital, Boston, MA, USA
| | - Natasha Fry
- North Shore Heart Research Group, Kolling Institute of Medical Research, University of Sydney, Australia
| | - Alvaro Garcia
- North Shore Heart Research Group, Kolling Institute of Medical Research, University of Sydney, Australia
| | - Elisha J Hamilton
- North Shore Heart Research Group, Kolling Institute of Medical Research, University of Sydney, Australia
| | - Kathleen J Sweadner
- Laboratory Membrane Biology, Massachusetts General Hospital, Boston, MA, USA
| | - Richard A Cohen
- Vascular Biology Section, Department of Medicine, Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, MA, USA
| | - Gemma A Figtree
- North Shore Heart Research Group, Kolling Institute of Medical Research, University of Sydney, Australia; Department of Cardiology, Royal North Shore Hospital, Sydney, Australia.
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