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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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2
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The role of AMPK in regulation of Na +,K +-ATPase in skeletal muscle: does the gauge always plug the sink? J Muscle Res Cell Motil 2021; 42:77-97. [PMID: 33398789 DOI: 10.1007/s10974-020-09594-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Accepted: 12/14/2020] [Indexed: 12/14/2022]
Abstract
AMP-activated protein kinase (AMPK) is a cellular energy gauge and a major regulator of cellular energy homeostasis. Once activated, AMPK stimulates nutrient uptake and the ATP-producing catabolic pathways, while it suppresses the ATP-consuming anabolic pathways, thus helping to maintain the cellular energy balance under energy-deprived conditions. As much as ~ 20-25% of the whole-body ATP consumption occurs due to a reaction catalysed by Na+,K+-ATPase (NKA). Being the single most important sink of energy, NKA might seem to be an essential target of the AMPK-mediated energy saving measures, yet NKA is vital for maintenance of transmembrane Na+ and K+ gradients, water homeostasis, cellular excitability, and the Na+-coupled transport of nutrients and ions. Consistent with the model that AMPK regulates ATP consumption by NKA, activation of AMPK in the lung alveolar cells stimulates endocytosis of NKA, thus suppressing the transepithelial ion transport and the absorption of the alveolar fluid. In skeletal muscles, contractions activate NKA, which opposes a rundown of transmembrane ion gradients, as well as AMPK, which plays an important role in adaptations to exercise. Inhibition of NKA in contracting skeletal muscle accentuates perturbations in ion concentrations and accelerates development of fatigue. However, different models suggest that AMPK does not inhibit or even stimulates NKA in skeletal muscle, which appears to contradict the idea that AMPK maintains the cellular energy balance by always suppressing ATP-consuming processes. In this short review, we examine the role of AMPK in regulation of NKA in skeletal muscle and discuss the apparent paradox of AMPK-stimulated ATP consumption.
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Feldman AM, Gordon J, Wang J, Song J, Zhang XQ, Myers VD, Tomar D, Gerhard GS, Khalili K, Cheung JY. Novel BAG3 Variants in African American Patients With Cardiomyopathy: Reduced β-Adrenergic Responsiveness in Excitation-Contraction. J Card Fail 2020; 26:1075-1085. [PMID: 32956817 DOI: 10.1016/j.cardfail.2020.09.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 05/27/2020] [Accepted: 09/11/2020] [Indexed: 11/16/2022]
Abstract
BACKGROUND We reported 3 novel nonsynonymous single nucleotide variants of Bcl2-associated athanogene 3 (BAG3) in African Americans with heart failure (HF) that are associated with a 2-fold increase in cardiac events (HF hospitalization, heart transplantation, or death). METHODS AND RESULTS We expressed BAG3 variants (P63A, P380S, and A479V) via adenovirus-mediated gene transfer in adult left ventricular myocytes isolated from either wild-type (WT) or cardiac-specific BAG3 haploinsufficient (cBAG3+/-) mice: the latter to simulate the clinical situation in which BAG3 variants are only found on 1 allele. Compared with WT myocytes, cBAG3+/- myocytes expressed approximately 50% of endogenous BAG3 levels and exhibited decreased [Ca2+]i and contraction amplitudes after isoproterenol owing to decreased L-type Ca2+ current. BAG3 repletion with WT BAG3 but not P380S, A479V, or P63A/P380S variants restored contraction amplitudes in cBAG3+/- myocytes to those measured in WT myocytes, suggesting excitation-contraction abnormalities partly account for HF in patients harboring these mutants. Because P63A is near the WW domain (residues 21-55) and A479V is in the BAG domain (residues 420-499), we expressed BAG3 deletion mutants (Δ1-61 and Δ421-575) in WT myocytes and demonstrated that the BAG but not the WW domain was involved in enhancement of excitation-contraction by isoproterenol. CONCLUSIONS The BAG3 variants contribute to HF in African American patients partly by decreasing myocyte excitation-contraction under stress, and that both the BAG and PXXP domains are involved in mediating β-adrenergic responsiveness in myocytes.
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Affiliation(s)
- Arthur M Feldman
- Department of Medicine, Lewis Katz School of Medicine of Temple University, Philadelphia, Pennsylvania
| | - Jennifer Gordon
- Department of Neuroscience and Comprehensive NeuroAIDS Center, Lewis Katz School of Medicine of Temple University, Philadelphia, Pennsylvania
| | - Jufang Wang
- Center for Translational Medicine, Lewis Katz School of Medicine of Temple University, Philadelphia, Pennsylvania
| | - Jianliang Song
- Center for Translational Medicine, Lewis Katz School of Medicine of Temple University, Philadelphia, Pennsylvania
| | - Xue-Qian Zhang
- Center for Translational Medicine, Lewis Katz School of Medicine of Temple University, Philadelphia, Pennsylvania
| | - Valerie D Myers
- Department of Medicine, Lewis Katz School of Medicine of Temple University, Philadelphia, Pennsylvania
| | - Dhanendra Tomar
- Center for Translational Medicine, Lewis Katz School of Medicine of Temple University, Philadelphia, Pennsylvania
| | - Glenn S Gerhard
- Department of Medical Genetics and Molecular Biochemistry, Lewis Katz School of Medicine of Temple University, Philadelphia, Pennsylvania
| | - Kamel Khalili
- Department of Neuroscience and Comprehensive NeuroAIDS Center, Lewis Katz School of Medicine of Temple University, Philadelphia, Pennsylvania
| | - Joseph Y Cheung
- Department of Medicine, Lewis Katz School of Medicine of Temple University, Philadelphia, Pennsylvania; Center for Translational Medicine, Lewis Katz School of Medicine of Temple University, Philadelphia, Pennsylvania.
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4
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Cardiomyocyte calcium handling in health and disease: Insights from in vitro and in silico studies. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2020; 157:54-75. [PMID: 32188566 DOI: 10.1016/j.pbiomolbio.2020.02.008] [Citation(s) in RCA: 63] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Revised: 12/31/2019] [Accepted: 02/29/2020] [Indexed: 02/07/2023]
Abstract
Calcium (Ca2+) plays a central role in cardiomyocyte excitation-contraction coupling. To ensure an optimal electrical impulse propagation and cardiac contraction, Ca2+ levels are regulated by a variety of Ca2+-handling proteins. In turn, Ca2+ modulates numerous electrophysiological processes. Accordingly, Ca2+-handling abnormalities can promote cardiac arrhythmias via various mechanisms, including the promotion of afterdepolarizations, ion-channel modulation and structural remodeling. In the last 30 years, significant improvements have been made in the computational modeling of cardiomyocyte Ca2+ handling under physiological and pathological conditions. However, numerous questions involving the Ca2+-dependent regulation of different macromolecular complexes, cross-talk between Ca2+-dependent regulatory pathways operating over a wide range of time scales, and bidirectional interactions between electrophysiology and mechanics remain to be addressed by in vitro and in silico studies. A better understanding of disease-specific Ca2+-dependent proarrhythmic mechanisms may facilitate the development of improved therapeutic strategies. In this review, we describe the fundamental mechanisms of cardiomyocyte Ca2+ handling in health and disease, and provide an overview of currently available computational models for cardiomyocyte Ca2+ handling. Finally, we discuss important uncertainties and open questions about cardiomyocyte Ca2+ handling and highlight how synergy between in vitro and in silico studies may help to answer several of these issues.
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Cheung JY, Merali S, Wang J, Zhang XQ, Song J, Merali C, Tomar D, You H, Judenherc-Haouzi A, Haouzi P. The central role of protein kinase C epsilon in cyanide cardiotoxicity and its treatment. Toxicol Sci 2019; 171:247-257. [PMID: 31173149 PMCID: PMC6735853 DOI: 10.1093/toxsci/kfz137] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Revised: 05/28/2019] [Accepted: 05/28/2019] [Indexed: 01/02/2023] Open
Abstract
In adult mouse myocytes, brief exposure to sodium cyanide (CN) in the presence of glucose does not decrease ATP levels, yet produces profound reduction in contractility, intracellular Ca2+ concentration ([Ca2+]i) transient and L-type Ca2+ current (ICa) amplitudes. We analyzed proteomes from myocytes exposed to CN, focusing on ionic currents associated with excitation-contraction coupling. CN induced phosphorylation of α1c subunit of L-type Ca2+ channel and α2 subunit of Na+-K+-ATPase. Methylene blue (MB), a CN antidote that we previously reported to ameliorate CN-induced reduction in contraction, [Ca2+]i transient and ICa amplitudes, was able to reverse this phosphorylation. CN decreased Na+-K+-ATPase current contributed by α2 but not α1 subunit, an effect that was also counteracted by MB. Peptide consensus sequences suggested CN-induced phosphorylation was mediated by protein kinase C epsilon (PKCε). Indeed, CN stimulated PKC kinase activity and induced PKCε membrane translocation, effects that were prevented by MB. Pre-treatment with myristoylated PKCε translocation activator or inhibitor peptides mimicked and inhibited the effects of CN on ICa and myocyte contraction, respectively. We conclude that CN activates PKCε, which phosphorylates L-type Ca2+ channel and Na+-K+-ATPase, resulting in depressed cardiac contractility. We hypothesize that this inhibition of ion fluxes represents a novel mechanism by which the cardiomyocyte reduces its ATP demand (decreased ion fluxes and contractility), diminishes ATP turnover and preserves cell viability. However, this cellular protective effect translates into life-threatening cardiogenic shock in vivo, thereby creating a profound disconnect between survival mechanisms at the cardiomyocyte level from those at the level of the whole organism.
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Affiliation(s)
- Joseph Y Cheung
- Center for Translational Medicine and Lewis Katz School of Medicine of Temple University, Philadelphia, PA.,Department of Medicine, Lewis Katz School of Medicine of Temple University, Philadelphia, PA
| | - Salim Merali
- Moulder Center for Drug Discovery Research, Temple University School of Pharmacy, Philadelphia, PA
| | - JuFang Wang
- Center for Translational Medicine and Lewis Katz School of Medicine of Temple University, Philadelphia, PA
| | - Xue-Qian Zhang
- Center for Translational Medicine and Lewis Katz School of Medicine of Temple University, Philadelphia, PA
| | - Jianliang Song
- Center for Translational Medicine and Lewis Katz School of Medicine of Temple University, Philadelphia, PA
| | - Carmen Merali
- Moulder Center for Drug Discovery Research, Temple University School of Pharmacy, Philadelphia, PA
| | - Dhanendra Tomar
- Center for Translational Medicine and Lewis Katz School of Medicine of Temple University, Philadelphia, PA
| | - Hanning You
- Department of Medicine, Lewis Katz School of Medicine of Temple University, Philadelphia, PA
| | | | - Philippe Haouzi
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Pennsylvania State University College of Medicine, Hershey, PA
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Hormonal regulation of Na +-K +-ATPase from the evolutionary perspective. CURRENT TOPICS IN MEMBRANES 2019; 83:315-351. [PMID: 31196608 DOI: 10.1016/bs.ctm.2019.01.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Na+-K+-ATPase, an α/β heterodimer, is an ancient enzyme that maintains Na+ and K+ gradients, thus preserving cellular ion homeostasis. In multicellular organisms, this basic housekeeping function is integrated to fulfill the needs of specialized organs and preserve whole-body homeostasis. In vertebrates, Na+-K+-ATPase is essential for many fundamental physiological processes, such as nerve conduction, muscle contraction, nutrient absorption, and urine excretion. During vertebrate evolution, three key developments contributed to diversification and integration of Na+-K+-ATPase functions. Generation of novel α- and β-subunits led to formation of multiple Na+-K+-ATPase isoenyzmes with distinct functional characteristics. Development of a complex endocrine system enabled efficient coordination of diverse Na+-K+-ATPase functions. Emergence of FXYDs, small transmembrane proteins that regulate Na+-K+-ATPase, opened new ways to modulate its function. FXYDs are a vertebrate innovation and an important site of hormonal action, suggesting they played an especially prominent role in evolving interaction between Na+-K+-ATPase and the endocrine system in vertebrates.
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Cheung JY, Wang J, Zhang XQ, Song J, Tomar D, Madesh M, Judenherc-Haouzi A, Haouzi P. Methylene blue counteracts cyanide cardiotoxicity: cellular mechanisms. J Appl Physiol (1985) 2018; 124:1164-1176. [PMID: 29420146 PMCID: PMC6050200 DOI: 10.1152/japplphysiol.00967.2017] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Revised: 01/09/2018] [Accepted: 02/01/2018] [Indexed: 11/22/2022] Open
Abstract
In adult left ventricular mouse myocytes, exposure to sodium cyanide (NaCN) in the presence of glucose dose-dependently reduced contraction amplitude, with ~80% of maximal inhibitory effect attained at 100 µM. NaCN (100 µM) exposure for 10 min significantly decreased contraction and intracellular Ca2+ concentration ([Ca2+]i) transient amplitudes, systolic but not diastolic [Ca2+]i, and maximal L-type Ca2+ current ( ICa) amplitude, indicating acute alteration of [Ca2+]i homeostasis largely accounted for the observed excitation-contraction abnormalities. In addition, NaCN depolarized resting membrane potential ( Em), reduced action potential (AP) amplitude, prolonged AP duration at 50% (APD50) and 90% repolarization (APD90), and suppressed depolarization-activated K+ currents but had no effect on Na+-Ca2+ exchange current ( INaCa). NaCN did not affect cellular adenosine triphosphate levels but depolarized mitochondrial membrane potential (ΔΨm) and increased superoxide (O2·-) levels. Methylene blue (MB; 20 µg/ml) added 3 min after NaCN restored contraction and [Ca2+]i transient amplitudes, systolic [Ca2+]i, Em, AP amplitude, APD50, APD90, ICa, depolarization-activated K+ currents, ΔΨm, and O2·- levels toward normal. We conclude that MB reversed NaCN-induced cardiotoxicity by preserving intracellular Ca2+ homeostasis and excitation-contraction coupling ( ICa), minimizing risks of arrhythmias ( Em, AP configuration, and depolarization-activated K+ currents), and reducing O2·- levels. NEW & NOTEWORTHY Cyanide poisoning due to industrial exposure, smoke inhalation, and bioterrorism manifests as cardiogenic shock and requires rapidly effective antidote. In the early stage of cyanide exposure, adenosine triphosphate levels are normal but myocyte contractility is reduced, largely due to alterations in Ca2+ homeostasis because of changes in oxidation-reduction environment of ion channels. Methylene blue, a drug approved by the U.S. Food and Drug Administration, ameliorates cyanide toxicity by normalizing oxidation-reduction state and Ca2+ channel function.
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Affiliation(s)
- Joseph Y Cheung
- Center of Translational Medicine, Lewis Katz School of Medicine, Temple University , Philadelphia, Pennsylvania
- Department of Medicine, Lewis Katz School of Medicine, Temple University , Philadelphia, Pennsylvania
| | - JuFang Wang
- Center of Translational Medicine, Lewis Katz School of Medicine, Temple University , Philadelphia, Pennsylvania
| | - Xue-Qian Zhang
- Center of Translational Medicine, Lewis Katz School of Medicine, Temple University , Philadelphia, Pennsylvania
| | - Jianliang Song
- Center of Translational Medicine, Lewis Katz School of Medicine, Temple University , Philadelphia, Pennsylvania
| | - Dhanendra Tomar
- Center of Translational Medicine, Lewis Katz School of Medicine, Temple University , Philadelphia, Pennsylvania
| | - Muniswamy Madesh
- Center of Translational Medicine, Lewis Katz School of Medicine, Temple University , Philadelphia, Pennsylvania
| | - Annick Judenherc-Haouzi
- Heart and Vascular Institute, Pennsylvania State University College of Medicine , Hershey, Pennsylvania
| | - Philippe Haouzi
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Pennsylvania State University College of Medicine , Hershey, Pennsylvania
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Wallner M, Eaton DM, Berretta RM, Borghetti G, Wu J, Baker ST, Feldsott EA, Sharp TE, Mohsin S, Oyama MA, von Lewinski D, Post H, Wolfson MR, Houser SR. A Feline HFpEF Model with Pulmonary Hypertension and Compromised Pulmonary Function. Sci Rep 2017; 7:16587. [PMID: 29185443 PMCID: PMC5707379 DOI: 10.1038/s41598-017-15851-2] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Accepted: 11/02/2017] [Indexed: 01/08/2023] Open
Abstract
Heart Failure with preserved Ejection Fraction (HFpEF) represents a major public health problem. The causative mechanisms are multifactorial and there are no effective treatments for HFpEF, partially attributable to the lack of well-established HFpEF animal models. We established a feline HFpEF model induced by slow-progressive pressure overload. Male domestic short hair cats (n = 20), underwent either sham procedures (n = 8) or aortic constriction (n = 12) with a customized pre-shaped band. Pulmonary function, gas exchange, and invasive hemodynamics were measured at 4-months post-banding. In banded cats, echocardiography at 4-months revealed concentric left ventricular (LV) hypertrophy, left atrial (LA) enlargement and dysfunction, and LV diastolic dysfunction with preserved systolic function, which subsequently led to elevated LV end-diastolic pressures and pulmonary hypertension. Furthermore, LV diastolic dysfunction was associated with increased LV fibrosis, cardiomyocyte hypertrophy, elevated NT-proBNP plasma levels, fluid and protein loss in pulmonary interstitium, impaired lung expansion, and alveolar-capillary membrane thickening. We report for the first time in HFpEF perivascular fluid cuff formation around extra-alveolar vessels with decreased respiratory compliance. Ultimately, these cardiopulmonary abnormalities resulted in impaired oxygenation. Our findings support the idea that this model can be used for testing novel therapeutic strategies to treat the ever growing HFpEF population.
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Affiliation(s)
- Markus Wallner
- Temple University Lewis Katz School of Medicine, Cardiovascular Research Center, Philadelphia, PA, United States.,Division of Cardiology, Department of Internal Medicine, Medical University of Graz, Graz, Austria
| | - Deborah M Eaton
- Temple University Lewis Katz School of Medicine, Cardiovascular Research Center, Philadelphia, PA, United States
| | - Remus M Berretta
- Temple University Lewis Katz School of Medicine, Cardiovascular Research Center, Philadelphia, PA, United States
| | - Giulia Borghetti
- Temple University Lewis Katz School of Medicine, Cardiovascular Research Center, Philadelphia, PA, United States
| | - Jichuan Wu
- Temple University Lewis Katz School of Medicine, Departments of Physiology, Thoracic Medicine and Surgery, Pediatrics, Center for Inflammation, Translational and Clinical Lung Research, CENTRe: Consortium for Environmental and Neonatal Therapeutics Research, Philadelphia, PA, United States
| | - Sandy T Baker
- Temple University Lewis Katz School of Medicine, Departments of Physiology, Thoracic Medicine and Surgery, Pediatrics, Center for Inflammation, Translational and Clinical Lung Research, CENTRe: Consortium for Environmental and Neonatal Therapeutics Research, Philadelphia, PA, United States
| | - Eric A Feldsott
- Temple University Lewis Katz School of Medicine, Cardiovascular Research Center, Philadelphia, PA, United States
| | - Thomas E Sharp
- Temple University Lewis Katz School of Medicine, Cardiovascular Research Center, Philadelphia, PA, United States
| | - Sadia Mohsin
- Temple University Lewis Katz School of Medicine, Cardiovascular Research Center, Philadelphia, PA, United States
| | - Mark A Oyama
- School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, United States.,Institute for Translational Medicine and Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Dirk von Lewinski
- Division of Cardiology, Department of Internal Medicine, Medical University of Graz, Graz, Austria
| | - Heiner Post
- Department of Cardiology, Campus Virchow-Klinikum, Charite Universitätsmedizin, Berlin, Germany
| | - Marla R Wolfson
- Temple University Lewis Katz School of Medicine, Departments of Physiology, Thoracic Medicine and Surgery, Pediatrics, Center for Inflammation, Translational and Clinical Lung Research, CENTRe: Consortium for Environmental and Neonatal Therapeutics Research, Philadelphia, PA, United States
| | - Steven R Houser
- Temple University Lewis Katz School of Medicine, Cardiovascular Research Center, Philadelphia, PA, United States.
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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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10
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Li S, Nong Y, Gao Q, Liu J, Li Y, Cui X, Wan J, Lu J, Sun M, Wu Q, Shi X, Cui H, Liu W, Zhou M, Li L, Lin Q. Astragalus Granule Prevents Ca 2+ Current Remodeling in Heart Failure by the Downregulation of CaMKII. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE : ECAM 2017; 2017:7517358. [PMID: 28855948 PMCID: PMC5569633 DOI: 10.1155/2017/7517358] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Accepted: 07/06/2017] [Indexed: 12/20/2022]
Abstract
BACKGROUND Astragalus was broadly used for treating heart failure (HF) and arrhythmias in East Asia for thousands of years. Astragalus granule (AG), extracted from Astragalus, shows beneficial effect on the treatment of HF in clinical research. We hypothesized that administration of AG prevents the remodeling of L-type Ca2+ current (ICa-L) in HF mice by the downregulation of Ca2+/calmodulin-dependent protein kinase II (CaMKII). METHODS HF mice were induced by thoracic aortic constriction (TAC). After 4 weeks of AG treatment, cardiac function and QT interval were evaluated. Single cardiac ventricular myocyte was then isolated and whole-cell patch clamp was used to record action potential (AP) and ICa-L. The expressions of L-type calcium channel alpha 1C subunit (Cav1.2), CaMKII, and phosphorylated protein kinase A (p-PKA) were examined by western blot. RESULTS The failing heart manifested distinct electrical remodeling including prolonged repolarization time and altered ICa-L kinetics. AG treatment attenuated this electrical remodeling, supported by AG-related shortened repolarization time, decreased peak ICa-L, accelerated ICa-L inactivation, and positive frequency-dependent ICa-L facilitation. In addition, AG treatment suppressed the overexpression of CaMKII, but not p-PKA, in the failing heart. CONCLUSION AG treatment protected the failing heart against electrical remodeling and ICa-L remodeling by downregulating CaMKII.
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Affiliation(s)
- Sinai Li
- Dongfang Hospital, Beijing University of Chinese Medicine, Beijing 100078, China
- Beijing Hospital of Traditional Chinese Medicine, Capital Medical University, Beijing Institute of Traditional Chinese Medicine, Beijing 100010, China
| | - Yibing Nong
- Dongfang Hospital, Beijing University of Chinese Medicine, Beijing 100078, China
- Department of Medicine, Institute of Molecular Cardiology, University of Louisville, Louisville, KY 40292, USA
| | - Qun Gao
- Dongfang Hospital, Beijing University of Chinese Medicine, Beijing 100078, China
| | - Jing Liu
- Dongfang Hospital, Beijing University of Chinese Medicine, Beijing 100078, China
| | - Yan Li
- Dongfang Hospital, Beijing University of Chinese Medicine, Beijing 100078, China
| | - Xiaoyun Cui
- Dongfang Hospital, Beijing University of Chinese Medicine, Beijing 100078, China
| | - Jie Wan
- Dongfang Hospital, Beijing University of Chinese Medicine, Beijing 100078, China
| | - Jinjin Lu
- Dongfang Hospital, Beijing University of Chinese Medicine, Beijing 100078, China
| | - Mingjie Sun
- Experimental Research Center, China Academy of Chinese Medical Sciences, Beijing 100700, China
| | - Qian Wu
- Experimental Research Center, China Academy of Chinese Medical Sciences, Beijing 100700, China
| | - Xiaolu Shi
- Experimental Research Center, China Academy of Chinese Medical Sciences, Beijing 100700, China
| | - Haifeng Cui
- Experimental Research Center, China Academy of Chinese Medical Sciences, Beijing 100700, China
| | - Weihong Liu
- Beijing Hospital of Traditional Chinese Medicine, Capital Medical University, Beijing Institute of Traditional Chinese Medicine, Beijing 100010, China
| | - Mingxue Zhou
- Beijing Hospital of Traditional Chinese Medicine, Capital Medical University, Beijing Institute of Traditional Chinese Medicine, Beijing 100010, China
| | - Lina Li
- College of Basic Medicine, Beijing University of Chinese Medicine, Beijing 100029, China
| | - Qian Lin
- Dongfang Hospital, Beijing University of Chinese Medicine, Beijing 100078, China
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11
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Pirkmajer S, Kirchner H, Lundell LS, Zelenin PV, Zierath JR, Makarova KS, Wolf YI, Chibalin AV. Early vertebrate origin and diversification of small transmembrane regulators of cellular ion transport. J Physiol 2017; 595:4611-4630. [PMID: 28436536 DOI: 10.1113/jp274254] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Accepted: 04/19/2017] [Indexed: 12/31/2022] Open
Abstract
KEY POINTS Small transmembrane proteins such as FXYDs, which interact with Na+ ,K+ -ATPase, and the micropeptides that interact with sarco/endoplasmic reticulum Ca2+ -ATPase play fundamental roles in regulation of ion transport in vertebrates. Uncertain evolutionary origins and phylogenetic relationships among these regulators of ion transport have led to inconsistencies in their classification across vertebrate species, thus hampering comparative studies of their functions. We discovered the first FXYD homologue in sea lamprey, a basal jawless vertebrate, which suggests small transmembrane regulators of ion transport emerged early in the vertebrate lineage. We also identified 13 gene subfamilies of FXYDs and propose a revised, phylogeny-based FXYD classification that is consistent across vertebrate species. These findings provide an improved framework for investigating physiological and pathophysiological functions of small transmembrane regulators of ion transport. ABSTRACT Small transmembrane proteins are important for regulation of cellular ion transport. The most prominent among these are members of the FXYD family (FXYD1-12), which regulate Na+ ,K+ -ATPase, and phospholamban, sarcolipin, myoregulin and DWORF, which regulate the sarco/endoplasmic reticulum Ca2+ -ATPase (SERCA). FXYDs and regulators of SERCA are present in fishes, as well as terrestrial vertebrates; however, their evolutionary origins and phylogenetic relationships are obscure, thus hampering comparative physiological studies. Here we discovered that sea lamprey (Petromyzon marinus), a representative of extant jawless vertebrates (Cyclostomata), expresses an FXYD homologue, which strongly suggests that FXYDs predate the emergence of fishes and other jawed vertebrates (Gnathostomata). Using a combination of sequence-based phylogenetic analysis and conservation of local chromosome context, we determined that FXYDs markedly diversified in the lineages leading to cartilaginous fishes (Chondrichthyes) and bony vertebrates (Euteleostomi). Diversification of SERCA regulators was much less extensive, indicating they operate under different evolutionary constraints. Finally, we found that FXYDs in extant vertebrates can be classified into 13 gene subfamilies, which do not always correspond to the established FXYD classification. We therefore propose a revised classification that is based on evolutionary history of FXYDs and that is consistent across vertebrate species. Collectively, our findings provide an improved framework for investigating the function of ion transport in health and disease.
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Affiliation(s)
- Sergej Pirkmajer
- Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, SI-1000, Ljubljana, Slovenia
| | - Henriette Kirchner
- Department of Physiology and Pharmacology, Karolinska Institutet, SE-171 77, Stockholm, Sweden
| | - Leonidas S Lundell
- Department of Physiology and Pharmacology, Karolinska Institutet, SE-171 77, Stockholm, Sweden
| | - Pavel V Zelenin
- Department of Neuroscience, Karolinska Institutet, SE-171 77, Stockholm, Sweden
| | - Juleen R Zierath
- Department of Physiology and Pharmacology, Karolinska Institutet, SE-171 77, Stockholm, Sweden.,Department of Molecular Medicine and Surgery, Karolinska Institutet, SE-171 77, Stockholm, Sweden
| | - Kira S Makarova
- National Center for Biotechnology Information, NLM, National Institutes of Health, Bethesda, MD, 20894, USA
| | - Yuri I Wolf
- National Center for Biotechnology Information, NLM, National Institutes of Health, Bethesda, MD, 20894, USA
| | - Alexander V Chibalin
- Department of Molecular Medicine and Surgery, Karolinska Institutet, SE-171 77, Stockholm, Sweden
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12
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Development of a high-affinity peptide that prevents phospholemman (PLM) inhibition of the sodium/calcium exchanger 1 (NCX1). Biochem J 2016; 473:2413-23. [PMID: 27247424 PMCID: PMC4964977 DOI: 10.1042/bcj20160465] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Accepted: 05/31/2016] [Indexed: 11/17/2022]
Abstract
NCX1 (Na+/Ca2+ exchanger 1) is an important regulator of intracellular Ca2+ and a potential therapeutic target for brain ischaemia and for diastolic heart failure with preserved ejection fraction. PLM (phospholemman), a substrate for protein kinases A and C, has been suggested to regulate NCX1 activity. However, although several studies have demonstrated that binding of phosphorylated PLM (pSer68-PLM) leads to NCX1 inhibition, other studies have failed to demonstrate a functional interaction of these proteins. In the present study, we aimed to analyse the biological function of the pSer68-PLM–NCX1 interaction by developing high-affinity blocking peptides. PLM was observed to co-fractionate and co-immunoprecipitate with NCX1 in rat left ventricle, and in co-transfected HEK (human embryonic kidney)-293 cells. For the first time, the NCX1–PLM interaction was also demonstrated in the brain. PLM binding sites on NCX1 were mapped to two regions by peptide array assays, containing the previously reported PASKT and QKHPD motifs. Conversely, the two NCX1 regions bound identical sequences in the cytoplasmic domain of PLM, suggesting that NCX1-PASKT and NCX1-QKHPD might bind to each PLM monomer. Using two-dimensional peptide arrays of the native NCX1 sequence KHPDKEIEQLIELANYQVLS revealed that double substitution of tyrosine for positions 1 and 4 (K1Y and D4Y) enhanced pSer68-PLM binding 8-fold. The optimized peptide blocked binding of NCX1-PASKT and NCX1-QKHPD to PLM and reversed PLM(S68D) inhibition of NCX1 activity (both forward and reverse mode) in HEK-293 cells. Altogether our data indicate that PLM interacts directly with NCX1 and inhibits NCX1 activity when phosphorylated at Ser68.
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13
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Feldman AM, Gordon J, Wang J, Song J, Zhang XQ, Myers VD, Tilley DG, Gao E, Hoffman NE, Tomar D, Madesh M, Rabinowitz J, Koch WJ, Su F, Khalili K, Cheung JY. BAG3 regulates contractility and Ca(2+) homeostasis in adult mouse ventricular myocytes. J Mol Cell Cardiol 2016; 92:10-20. [PMID: 26796036 PMCID: PMC4789075 DOI: 10.1016/j.yjmcc.2016.01.015] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Revised: 01/14/2016] [Accepted: 01/17/2016] [Indexed: 12/22/2022]
Abstract
Bcl2-associated athanogene 3 (BAG3) is a 575 amino acid anti-apoptotic protein that is constitutively expressed in the heart. BAG3 mutations, including mutations leading to loss of protein, are associated with familial cardiomyopathy. Furthermore, BAG3 levels have been found to be reduced in end-stage non-familial failing myocardium. In contrast to neonatal myocytes in which BAG3 is found in the cytoplasm and involved in protein quality control and apoptosis, in adult mouse left ventricular (LV) myocytes BAG3 co-localized with Na(+)-K(+)-ATPase and L-type Ca(2+) channels in the sarcolemma and t-tubules. BAG3 co-immunoprecipitated with β1-adrenergic receptor, L-type Ca(2+) channels and phospholemman. To simulate decreased BAG3 protein levels observed in human heart failure, we targeted BAG3 by shRNA (shBAG3) in adult LV myocytes. Reducing BAG3 by 55% resulted in reduced contraction and [Ca(2+)]i transient amplitudes in LV myocytes stimulated with isoproterenol. L-type Ca(2+) current (ICa) and sarcoplasmic reticulum (SR) Ca(2+) content but not Na(+)/Ca(2+) exchange current (INaCa) or SR Ca(2+) uptake were reduced in isoproterenol-treated shBAG3 myocytes. Forskolin or dibutyryl cAMP restored ICa amplitude in shBAG3 myocytes to that observed in WT myocytes, consistent with BAG3 having effects upstream and at the level of the receptor. Resting membrane potential and action potential amplitude were unaffected but APD50 and APD90 were prolonged in shBAG3 myocytes. Protein levels of Ca(2+) entry molecules and other important excitation-contraction proteins were unchanged in myocytes with lower BAG3. Our findings that BAG3 is localized at the sarcolemma and t-tubules while modulating myocyte contraction and action potential duration through specific interaction with the β1-adrenergic receptor and L-type Ca(2+) channel provide novel insight into the role of BAG3 in cardiomyopathies and increased arrhythmia risks in heart failure.
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MESH Headings
- Action Potentials/drug effects
- Adaptor Proteins, Signal Transducing/biosynthesis
- Adaptor Proteins, Signal Transducing/genetics
- Animals
- Apoptosis Regulatory Proteins/biosynthesis
- Apoptosis Regulatory Proteins/genetics
- Arrhythmias, Cardiac/genetics
- Arrhythmias, Cardiac/metabolism
- Arrhythmias, Cardiac/pathology
- Calcium/metabolism
- Calcium Channels, L-Type/metabolism
- Cardiomyopathy, Dilated/genetics
- Cardiomyopathy, Dilated/metabolism
- Cardiomyopathy, Dilated/pathology
- Excitation Contraction Coupling
- Heart Failure/genetics
- Heart Failure/metabolism
- Heart Failure/pathology
- Heart Ventricles/metabolism
- Heart Ventricles/pathology
- Homeostasis
- Humans
- Isoproterenol/administration & dosage
- Membrane Proteins/metabolism
- Mice
- Myocytes, Cardiac/metabolism
- Myocytes, Cardiac/pathology
- Phosphoproteins/metabolism
- RNA, Small Interfering/genetics
- Receptors, Adrenergic, beta-1/metabolism
- Sarcolemma/metabolism
- Sodium-Potassium-Exchanging ATPase/metabolism
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Affiliation(s)
- Arthur M Feldman
- Department of Medicine, Temple University School of Medicine, Philadelphia, PA 19140, USA; Cardiovascular Research Center, Temple University School of Medicine, Philadelphia, PA 19140, USA
| | - Jennifer Gordon
- Comprehensive NeuroAIDS Center, Temple University School of Medicine, Philadelphia, PA 19140, USA
| | - JuFang Wang
- Center of Translational Medicine, Temple University School of Medicine, Philadelphia, PA 19140, USA
| | - Jianliang Song
- Center of Translational Medicine, Temple University School of Medicine, Philadelphia, PA 19140, USA
| | - Xue-Qian Zhang
- Center of Translational Medicine, Temple University School of Medicine, Philadelphia, PA 19140, USA
| | - Valerie D Myers
- Cardiovascular Research Center, Temple University School of Medicine, Philadelphia, PA 19140, USA
| | - Douglas G Tilley
- Center of Translational Medicine, Temple University School of Medicine, Philadelphia, PA 19140, USA
| | - Erhe Gao
- Center of Translational Medicine, Temple University School of Medicine, Philadelphia, PA 19140, USA
| | - Nicholas E Hoffman
- Center of Translational Medicine, Temple University School of Medicine, Philadelphia, PA 19140, USA
| | - Dhanendra Tomar
- Center of Translational Medicine, Temple University School of Medicine, Philadelphia, PA 19140, USA
| | - Muniswamy Madesh
- Center of Translational Medicine, Temple University School of Medicine, Philadelphia, PA 19140, USA
| | - Joseph Rabinowitz
- Center of Translational Medicine, Temple University School of Medicine, Philadelphia, PA 19140, USA
| | - Walter J Koch
- Center of Translational Medicine, Temple University School of Medicine, Philadelphia, PA 19140, USA
| | - Feifei Su
- Cardiovascular Research Center, Temple University School of Medicine, Philadelphia, PA 19140, USA; Department of Cardiology, Tangdu Hospital, the Fourth Military Medical University, Xi'an, China
| | - Kamel Khalili
- Comprehensive NeuroAIDS Center, Temple University School of Medicine, Philadelphia, PA 19140, USA
| | - Joseph Y Cheung
- Center of Translational Medicine, Temple University School of Medicine, Philadelphia, PA 19140, USA; Department of Medicine, Temple University School of Medicine, Philadelphia, PA 19140, USA.
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