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Arrell DK, Park S, Yamada S, Alekseev AE, Garmany A, Jeon R, Vuckovic I, Lindor JZ, Terzic A. K ATP channel dependent heart multiome atlas. Sci Rep 2022; 12:7314. [PMID: 35513538 PMCID: PMC9072320 DOI: 10.1038/s41598-022-11323-4] [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: 12/15/2021] [Accepted: 04/21/2022] [Indexed: 11/09/2022] Open
Abstract
Plasmalemmal ATP sensitive potassium (KATP) channels are recognized metabolic sensors, yet their cellular reach is less well understood. Here, transgenic Kir6.2 null hearts devoid of the KATP channel pore underwent multiomics surveillance and systems interrogation versus wildtype counterparts. Despite maintained organ performance, the knockout proteome deviated beyond a discrete loss of constitutive KATP channel subunits. Multidimensional nano-flow liquid chromatography tandem mass spectrometry resolved 111 differentially expressed proteins and their expanded network neighborhood, dominated by metabolic process engagement. Independent multimodal chemometric gas and liquid chromatography mass spectrometry unveiled differential expression of over one quarter of measured metabolites discriminating the Kir6.2 deficient heart metabolome. Supervised class analogy ranking and unsupervised enrichment analysis prioritized nicotinamide adenine dinucleotide (NAD+), affirmed by extensive overrepresentation of NAD+ associated circuitry. The remodeled metabolome and proteome revealed functional convergence and an integrated signature of disease susceptibility. Deciphered cardiac patterns were traceable in the corresponding plasma metabolome, with tissue concordant plasma changes offering surrogate metabolite markers of myocardial latent vulnerability. Thus, Kir6.2 deficit precipitates multiome reorganization, mapping a comprehensive atlas of the KATP channel dependent landscape.
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Affiliation(s)
- D Kent Arrell
- Marriott Heart Disease Research Program, Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN, USA.,Marriott Family Comprehensive Cardiac Regenerative Medicine, Center for Regenerative Medicine, Mayo Clinic, Rochester, MN, USA.,Department of Molecular Pharmacology & Experimental Therapeutics, Mayo Clinic, Rochester, MN, USA
| | - Sungjo Park
- Marriott Heart Disease Research Program, Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN, USA.,Marriott Family Comprehensive Cardiac Regenerative Medicine, Center for Regenerative Medicine, Mayo Clinic, Rochester, MN, USA.,Department of Molecular Pharmacology & Experimental Therapeutics, Mayo Clinic, Rochester, MN, USA.,Department of Biochemistry & Molecular Biology, Mayo Clinic, Rochester, MN, USA
| | - Satsuki Yamada
- Marriott Heart Disease Research Program, Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN, USA.,Marriott Family Comprehensive Cardiac Regenerative Medicine, Center for Regenerative Medicine, Mayo Clinic, Rochester, MN, USA.,Department of Molecular Pharmacology & Experimental Therapeutics, Mayo Clinic, Rochester, MN, USA.,Division of Geriatric Medicine & Gerontology, Department of Medicine, Mayo Clinic, Rochester, MN, USA
| | - Alexey E Alekseev
- Marriott Heart Disease Research Program, Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN, USA.,Marriott Family Comprehensive Cardiac Regenerative Medicine, Center for Regenerative Medicine, Mayo Clinic, Rochester, MN, USA.,Department of Molecular Pharmacology & Experimental Therapeutics, Mayo Clinic, Rochester, MN, USA.,Institute of Theoretical and Experimental Biophysics, Russian Academy of Science, Pushchino, Moscow Region, Russia
| | - Armin Garmany
- Marriott Heart Disease Research Program, Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN, USA.,Marriott Family Comprehensive Cardiac Regenerative Medicine, Center for Regenerative Medicine, Mayo Clinic, Rochester, MN, USA.,Department of Molecular Pharmacology & Experimental Therapeutics, Mayo Clinic, Rochester, MN, USA.,Mayo Clinic Alix School of Medicine, Regenerative Sciences Track, Mayo Clinic Graduate School of Biomedical Sciences, Mayo Clinic, Rochester, MN, USA
| | - Ryounghoon Jeon
- Marriott Heart Disease Research Program, Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN, USA.,Marriott Family Comprehensive Cardiac Regenerative Medicine, Center for Regenerative Medicine, Mayo Clinic, Rochester, MN, USA.,Department of Molecular Pharmacology & Experimental Therapeutics, Mayo Clinic, Rochester, MN, USA
| | - Ivan Vuckovic
- Department of Biochemistry & Molecular Biology, Mayo Clinic, Rochester, MN, USA.,Metabolomics Core, Mayo Clinic, Rochester, MN, USA
| | - Jelena Zlatkovic Lindor
- Marriott Heart Disease Research Program, Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN, USA.,Department of Molecular Pharmacology & Experimental Therapeutics, Mayo Clinic, Rochester, MN, USA
| | - Andre Terzic
- Marriott Heart Disease Research Program, Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN, USA. .,Marriott Family Comprehensive Cardiac Regenerative Medicine, Center for Regenerative Medicine, Mayo Clinic, Rochester, MN, USA. .,Department of Molecular Pharmacology & Experimental Therapeutics, Mayo Clinic, Rochester, MN, USA. .,Department of Clinical Genomics, Mayo Clinic, Rochester, MN, USA.
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Diazoxide Preconditioning of Nonhuman Primate Pancreas Improves Islet Isolation Outcomes by Mitochondrial Protection. Pancreas 2020; 49:706-713. [PMID: 32433410 DOI: 10.1097/mpa.0000000000001557] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
Abstract
OBJECTIVES Previously, we showed that diazoxide (DZ), an effective ischemic preconditioning agent, protected rodent pancreas against ischemia-reperfusion injury. Here, we further investigate whether DZ supplementation to University of Wisconsin (UW) solution during pancreas procurement and islet isolation has similar cytoprotection in a preclinical nonhuman primate model. METHODS Cynomolgus monkey pancreata were flushed with UW or UW + 150 μM DZ during procurement and preserved for 8 hours before islet isolation. RESULTS First, a significantly higher islet yield was observed in UW + DZ than in UW (57,887 vs 23,574 IEq/pancreas and 5396 vs 1646 IEq/g). Second, the DZ treated islets had significantly lower apoptotic cells per islet (1.64% vs 9.85%). Third, DZ significantly inhibited ROS surge during reperfusion with a dose-response manner. Fourth, DZ improved in vitro function of isolated islets determined by mitochondrial potentials and calcium influx in responses to glucose and KCI. Fifth, the DZ treated islets had much higher cure rate and better glycemia control in diabetic mice transplant model. CONCLUSIONS This study showed a strong mitochondrial protection of DZ on nonhuman primate islets against ischemia-reperfusion injury that provides strong evidence for its clinical application in islet and pancreas transplantation.
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Huang Y, Hu D, Huang C, Nichols CG. Genetic Discovery of ATP-Sensitive K + Channels in Cardiovascular Diseases. Circ Arrhythm Electrophysiol 2020; 12:e007322. [PMID: 31030551 DOI: 10.1161/circep.119.007322] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The ATP-sensitive K+ (KATP) channels are hetero-octameric protein complexes comprising 4 pore-forming (Kir6.x) subunits and 4 regulatory sulfonylurea receptor (SURx) subunits. They are prominent in myocytes, pancreatic β cells, and neurons and link cellular metabolism with membrane excitability. Using genetically modified animals and genomic analysis in patients, recent studies have implicated certain ATP-sensitive K+ channel subtypes in physiological and pathological processes in a variety of cardiovascular diseases. In this review, we focus on the causal relationship between ATP-sensitive K+ channel activity and pathophysiology in the cardiovascular system, particularly from the perspective of genetic changes in human and animal models.
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Affiliation(s)
- Yan Huang
- Department of Cardiology, Renmin Hospital of Wuhan University; Cardiovascular Research Institute, Wuhan University, PR China (Y.H., D.H., C.H.).,Hubei Key Laboratory of Cardiology, Wuhan, PR China (Y.H., D.H., C.H.)
| | - Dan Hu
- Department of Cardiology, Renmin Hospital of Wuhan University; Cardiovascular Research Institute, Wuhan University, PR China (Y.H., D.H., C.H.).,Hubei Key Laboratory of Cardiology, Wuhan, PR China (Y.H., D.H., C.H.)
| | - Congxin Huang
- Department of Cardiology, Renmin Hospital of Wuhan University; Cardiovascular Research Institute, Wuhan University, PR China (Y.H., D.H., C.H.).,Hubei Key Laboratory of Cardiology, Wuhan, PR China (Y.H., D.H., C.H.)
| | - Colin G Nichols
- Center for the Investigation of Membrane Excitability Diseases and Department of Cell Biology and Physiology, Washington University School of Medicine, Saint Louis, MO (C.G.N.)
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Youssef N, Campbell S, Barr A, Gandhi M, Hunter B, Dolinsky V, Dyck JRB, Clanachan AS, Light PE. Hearts lacking plasma membrane KATP channels display changes in basal aerobic metabolic substrate preference and AMPK activity. Am J Physiol Heart Circ Physiol 2017; 313:H469-H478. [DOI: 10.1152/ajpheart.00612.2016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Revised: 06/13/2017] [Accepted: 06/13/2017] [Indexed: 12/12/2022]
Abstract
Cardiac ATP-sensitive K+ (KATP) channels couple changes in cellular metabolism to membrane excitability and are activated during metabolic stress, although under basal aerobic conditions, KATP channels are thought to be predominately closed. Despite intense research into the roles of KATP channels during metabolic stress, their contribution to aerobic basal cardiac metabolism has not been previously investigated. Hearts from Kir6.2+/+ and Kir6.2−/− mice were perfused in working mode, and rates of glycolysis, fatty acid oxidation, and glucose oxidation were measured. Changes in activation/expression of proteins regulating metabolism were probed by Western blot analysis. Despite cardiac mechanical function and metabolic efficiency being similar in both groups, hearts from Kir6.2−/− mice displayed an approximately twofold increase in fatty acid oxidation and a 0.45-fold reduction in glycolytic rates but similar glucose oxidation rates compared with hearts from Kir6.2+/+ mice. Kir6.2−/− hearts also possessed elevated levels of activated AMP-activated protein kinase (AMPK), higher glycogen content, and reduced mitochondrial density. Moreover, activation of AMPK by isoproterenol or diazoxide was significantly blunted in Kir6.2−/− hearts. These data indicate that KATP channel ablation alters aerobic basal cardiac metabolism. The observed increase in fatty acid oxidation and decreased glycolysis before any metabolic insult may contribute to the poor recovery observed in Kir6.2−/− hearts in response to exercise or ischemia-reperfusion injury. Therefore, KATP channels may play an important role in the regulation of cardiac metabolism through AMPK signaling. NEW & NOTEWORTHY In this study, we show that genetic ablation of plasma membrane ATP-sensitive K+ channels results in pronounced changes in cardiac metabolic substrate preference and AMP-activated protein kinase activity. These results suggest that ATP-sensitive K+ channels may play a novel role in regulating metabolism in addition to their well-documented effects on ionic homeostasis during periods of stress.
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Affiliation(s)
- Nermeen Youssef
- Department of Pharmacology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Scott Campbell
- Department of Pharmacology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Amy Barr
- Department of Pharmacology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Manoj Gandhi
- Department of Pharmacology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Beth Hunter
- Department of Pharmacology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Vernon Dolinsky
- Children’s Hospital Research Institute of Manitoba, Department of Pharmacology and Therapeutics, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Jason R. B. Dyck
- Department of Pediatrics, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada; and
| | - Alexander S. Clanachan
- Department of Pharmacology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Peter E. Light
- Department of Pharmacology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
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Zhang B, Novitskaya T, Wheeler DG, Xu Z, Chepurko E, Huttinger R, He H, Varadharaj S, Zweier JL, Song Y, Xu M, Harrell FE, Su YR, Absi T, Kohr MJ, Ziolo MT, Roden DM, Shaffer CM, Galindo CL, Wells QS, Gumina RJ. Kcnj11 Ablation Is Associated With Increased Nitro-Oxidative Stress During Ischemia-Reperfusion Injury: Implications for Human Ischemic Cardiomyopathy. Circ Heart Fail 2017; 10:CIRCHEARTFAILURE.116.003523. [PMID: 28209764 DOI: 10.1161/circheartfailure.116.003523] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Accepted: 01/06/2017] [Indexed: 11/16/2022]
Abstract
BACKGROUND Despite increased secondary cardiovascular events in patients with ischemic cardiomyopathy (ICM), the expression of innate cardiac protective molecules in the hearts of patients with ICM is incompletely characterized. Therefore, we used a nonbiased RNAseq approach to determine whether differences in cardiac protective molecules occur with ICM. METHODS AND RESULTS RNAseq analysis of human control and ICM left ventricular samples demonstrated a significant decrease in KCNJ11 expression with ICM. KCNJ11 encodes the Kir6.2 subunit of the cardioprotective KATP channel. Using wild-type mice and kcnj11-deficient (kcnj11-null) mice, we examined the effect of kcnj11 expression on cardiac function during ischemia-reperfusion injury. Reactive oxygen species generation increased in kcnj11-null hearts above that found in wild-type mice hearts after ischemia-reperfusion injury. Continuous left ventricular pressure measurement during ischemia and reperfusion demonstrated a more compromised diastolic function in kcnj11-null compared with wild-type mice during reperfusion. Analysis of key calcium-regulating proteins revealed significant differences in kcnj11-null mice. Despite impaired relaxation, kcnj11-null hearts increased phospholamban Ser16 phosphorylation, a modification that results in the dissociation of phospholamban from sarcoendoplasmic reticulum Ca2+, thereby increasing sarcoendoplasmic reticulum Ca2+-mediated calcium reuptake. However, kcnj11-null mice also had increased 3-nitrotyrosine modification of the sarcoendoplasmic reticulum Ca2+-ATPase, a modification that irreversibly impairs sarcoendoplasmic reticulum Ca2+ function, thereby contributing to diastolic dysfunction. CONCLUSIONS KCNJ11 expression is decreased in human ICM. Lack of kcnj11 expression increases peroxynitrite-mediated modification of the key calcium-handling protein sarcoendoplasmic reticulum Ca2+-ATPase after myocardial ischemia-reperfusion injury, contributing to impaired diastolic function. These data suggest a mechanism for ischemia-induced diastolic dysfunction in patients with ICM.
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Affiliation(s)
- Bo Zhang
- From the Division of Cardiovascular Medicine, Davis Heart and Lung Research Institute (B.Z., D.G.W., Z.X., R.H., H.H., S.V., J.L.Z.), Department of Physiology and Cell Biology (B.Z., J.L.Z., M.J.K., M.T.Z.), The Ohio State University, Columbus; Institute of Organ Transplantation, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, HuBei, China (B.Z.); Department of Biostatistics (Y.S., M.X., F.E.H.), Division of Clinical Pharmacology, Department of Medicine (D.M.R., C.M.S.), Division of Cardiac Surgery, Department of Surgery (T.A.), Division of Cardiovascular Medicine (T. N., E. C., Y.R.S., D.R., C.L.G., Q.S.W, R.J.G.), Department of Pharmacology and Department of Pathology, Immunology, and Microbiology (R.J.G.), Vanderbilt University Medical Center, Nashville, TN
| | - Tatiana Novitskaya
- From the Division of Cardiovascular Medicine, Davis Heart and Lung Research Institute (B.Z., D.G.W., Z.X., R.H., H.H., S.V., J.L.Z.), Department of Physiology and Cell Biology (B.Z., J.L.Z., M.J.K., M.T.Z.), The Ohio State University, Columbus; Institute of Organ Transplantation, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, HuBei, China (B.Z.); Department of Biostatistics (Y.S., M.X., F.E.H.), Division of Clinical Pharmacology, Department of Medicine (D.M.R., C.M.S.), Division of Cardiac Surgery, Department of Surgery (T.A.), Division of Cardiovascular Medicine (T. N., E. C., Y.R.S., D.R., C.L.G., Q.S.W, R.J.G.), Department of Pharmacology and Department of Pathology, Immunology, and Microbiology (R.J.G.), Vanderbilt University Medical Center, Nashville, TN
| | - Debra G Wheeler
- From the Division of Cardiovascular Medicine, Davis Heart and Lung Research Institute (B.Z., D.G.W., Z.X., R.H., H.H., S.V., J.L.Z.), Department of Physiology and Cell Biology (B.Z., J.L.Z., M.J.K., M.T.Z.), The Ohio State University, Columbus; Institute of Organ Transplantation, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, HuBei, China (B.Z.); Department of Biostatistics (Y.S., M.X., F.E.H.), Division of Clinical Pharmacology, Department of Medicine (D.M.R., C.M.S.), Division of Cardiac Surgery, Department of Surgery (T.A.), Division of Cardiovascular Medicine (T. N., E. C., Y.R.S., D.R., C.L.G., Q.S.W, R.J.G.), Department of Pharmacology and Department of Pathology, Immunology, and Microbiology (R.J.G.), Vanderbilt University Medical Center, Nashville, TN
| | - Zhaobin Xu
- From the Division of Cardiovascular Medicine, Davis Heart and Lung Research Institute (B.Z., D.G.W., Z.X., R.H., H.H., S.V., J.L.Z.), Department of Physiology and Cell Biology (B.Z., J.L.Z., M.J.K., M.T.Z.), The Ohio State University, Columbus; Institute of Organ Transplantation, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, HuBei, China (B.Z.); Department of Biostatistics (Y.S., M.X., F.E.H.), Division of Clinical Pharmacology, Department of Medicine (D.M.R., C.M.S.), Division of Cardiac Surgery, Department of Surgery (T.A.), Division of Cardiovascular Medicine (T. N., E. C., Y.R.S., D.R., C.L.G., Q.S.W, R.J.G.), Department of Pharmacology and Department of Pathology, Immunology, and Microbiology (R.J.G.), Vanderbilt University Medical Center, Nashville, TN
| | - Elena Chepurko
- From the Division of Cardiovascular Medicine, Davis Heart and Lung Research Institute (B.Z., D.G.W., Z.X., R.H., H.H., S.V., J.L.Z.), Department of Physiology and Cell Biology (B.Z., J.L.Z., M.J.K., M.T.Z.), The Ohio State University, Columbus; Institute of Organ Transplantation, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, HuBei, China (B.Z.); Department of Biostatistics (Y.S., M.X., F.E.H.), Division of Clinical Pharmacology, Department of Medicine (D.M.R., C.M.S.), Division of Cardiac Surgery, Department of Surgery (T.A.), Division of Cardiovascular Medicine (T. N., E. C., Y.R.S., D.R., C.L.G., Q.S.W, R.J.G.), Department of Pharmacology and Department of Pathology, Immunology, and Microbiology (R.J.G.), Vanderbilt University Medical Center, Nashville, TN
| | - Ryan Huttinger
- From the Division of Cardiovascular Medicine, Davis Heart and Lung Research Institute (B.Z., D.G.W., Z.X., R.H., H.H., S.V., J.L.Z.), Department of Physiology and Cell Biology (B.Z., J.L.Z., M.J.K., M.T.Z.), The Ohio State University, Columbus; Institute of Organ Transplantation, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, HuBei, China (B.Z.); Department of Biostatistics (Y.S., M.X., F.E.H.), Division of Clinical Pharmacology, Department of Medicine (D.M.R., C.M.S.), Division of Cardiac Surgery, Department of Surgery (T.A.), Division of Cardiovascular Medicine (T. N., E. C., Y.R.S., D.R., C.L.G., Q.S.W, R.J.G.), Department of Pharmacology and Department of Pathology, Immunology, and Microbiology (R.J.G.), Vanderbilt University Medical Center, Nashville, TN
| | - Heng He
- From the Division of Cardiovascular Medicine, Davis Heart and Lung Research Institute (B.Z., D.G.W., Z.X., R.H., H.H., S.V., J.L.Z.), Department of Physiology and Cell Biology (B.Z., J.L.Z., M.J.K., M.T.Z.), The Ohio State University, Columbus; Institute of Organ Transplantation, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, HuBei, China (B.Z.); Department of Biostatistics (Y.S., M.X., F.E.H.), Division of Clinical Pharmacology, Department of Medicine (D.M.R., C.M.S.), Division of Cardiac Surgery, Department of Surgery (T.A.), Division of Cardiovascular Medicine (T. N., E. C., Y.R.S., D.R., C.L.G., Q.S.W, R.J.G.), Department of Pharmacology and Department of Pathology, Immunology, and Microbiology (R.J.G.), Vanderbilt University Medical Center, Nashville, TN
| | - Saradhadevi Varadharaj
- From the Division of Cardiovascular Medicine, Davis Heart and Lung Research Institute (B.Z., D.G.W., Z.X., R.H., H.H., S.V., J.L.Z.), Department of Physiology and Cell Biology (B.Z., J.L.Z., M.J.K., M.T.Z.), The Ohio State University, Columbus; Institute of Organ Transplantation, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, HuBei, China (B.Z.); Department of Biostatistics (Y.S., M.X., F.E.H.), Division of Clinical Pharmacology, Department of Medicine (D.M.R., C.M.S.), Division of Cardiac Surgery, Department of Surgery (T.A.), Division of Cardiovascular Medicine (T. N., E. C., Y.R.S., D.R., C.L.G., Q.S.W, R.J.G.), Department of Pharmacology and Department of Pathology, Immunology, and Microbiology (R.J.G.), Vanderbilt University Medical Center, Nashville, TN
| | - Jay L Zweier
- From the Division of Cardiovascular Medicine, Davis Heart and Lung Research Institute (B.Z., D.G.W., Z.X., R.H., H.H., S.V., J.L.Z.), Department of Physiology and Cell Biology (B.Z., J.L.Z., M.J.K., M.T.Z.), The Ohio State University, Columbus; Institute of Organ Transplantation, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, HuBei, China (B.Z.); Department of Biostatistics (Y.S., M.X., F.E.H.), Division of Clinical Pharmacology, Department of Medicine (D.M.R., C.M.S.), Division of Cardiac Surgery, Department of Surgery (T.A.), Division of Cardiovascular Medicine (T. N., E. C., Y.R.S., D.R., C.L.G., Q.S.W, R.J.G.), Department of Pharmacology and Department of Pathology, Immunology, and Microbiology (R.J.G.), Vanderbilt University Medical Center, Nashville, TN
| | - Yanna Song
- From the Division of Cardiovascular Medicine, Davis Heart and Lung Research Institute (B.Z., D.G.W., Z.X., R.H., H.H., S.V., J.L.Z.), Department of Physiology and Cell Biology (B.Z., J.L.Z., M.J.K., M.T.Z.), The Ohio State University, Columbus; Institute of Organ Transplantation, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, HuBei, China (B.Z.); Department of Biostatistics (Y.S., M.X., F.E.H.), Division of Clinical Pharmacology, Department of Medicine (D.M.R., C.M.S.), Division of Cardiac Surgery, Department of Surgery (T.A.), Division of Cardiovascular Medicine (T. N., E. C., Y.R.S., D.R., C.L.G., Q.S.W, R.J.G.), Department of Pharmacology and Department of Pathology, Immunology, and Microbiology (R.J.G.), Vanderbilt University Medical Center, Nashville, TN
| | - Meng Xu
- From the Division of Cardiovascular Medicine, Davis Heart and Lung Research Institute (B.Z., D.G.W., Z.X., R.H., H.H., S.V., J.L.Z.), Department of Physiology and Cell Biology (B.Z., J.L.Z., M.J.K., M.T.Z.), The Ohio State University, Columbus; Institute of Organ Transplantation, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, HuBei, China (B.Z.); Department of Biostatistics (Y.S., M.X., F.E.H.), Division of Clinical Pharmacology, Department of Medicine (D.M.R., C.M.S.), Division of Cardiac Surgery, Department of Surgery (T.A.), Division of Cardiovascular Medicine (T. N., E. C., Y.R.S., D.R., C.L.G., Q.S.W, R.J.G.), Department of Pharmacology and Department of Pathology, Immunology, and Microbiology (R.J.G.), Vanderbilt University Medical Center, Nashville, TN
| | - Frank E Harrell
- From the Division of Cardiovascular Medicine, Davis Heart and Lung Research Institute (B.Z., D.G.W., Z.X., R.H., H.H., S.V., J.L.Z.), Department of Physiology and Cell Biology (B.Z., J.L.Z., M.J.K., M.T.Z.), The Ohio State University, Columbus; Institute of Organ Transplantation, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, HuBei, China (B.Z.); Department of Biostatistics (Y.S., M.X., F.E.H.), Division of Clinical Pharmacology, Department of Medicine (D.M.R., C.M.S.), Division of Cardiac Surgery, Department of Surgery (T.A.), Division of Cardiovascular Medicine (T. N., E. C., Y.R.S., D.R., C.L.G., Q.S.W, R.J.G.), Department of Pharmacology and Department of Pathology, Immunology, and Microbiology (R.J.G.), Vanderbilt University Medical Center, Nashville, TN
| | - Yan Ru Su
- From the Division of Cardiovascular Medicine, Davis Heart and Lung Research Institute (B.Z., D.G.W., Z.X., R.H., H.H., S.V., J.L.Z.), Department of Physiology and Cell Biology (B.Z., J.L.Z., M.J.K., M.T.Z.), The Ohio State University, Columbus; Institute of Organ Transplantation, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, HuBei, China (B.Z.); Department of Biostatistics (Y.S., M.X., F.E.H.), Division of Clinical Pharmacology, Department of Medicine (D.M.R., C.M.S.), Division of Cardiac Surgery, Department of Surgery (T.A.), Division of Cardiovascular Medicine (T. N., E. C., Y.R.S., D.R., C.L.G., Q.S.W, R.J.G.), Department of Pharmacology and Department of Pathology, Immunology, and Microbiology (R.J.G.), Vanderbilt University Medical Center, Nashville, TN
| | - Tarek Absi
- From the Division of Cardiovascular Medicine, Davis Heart and Lung Research Institute (B.Z., D.G.W., Z.X., R.H., H.H., S.V., J.L.Z.), Department of Physiology and Cell Biology (B.Z., J.L.Z., M.J.K., M.T.Z.), The Ohio State University, Columbus; Institute of Organ Transplantation, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, HuBei, China (B.Z.); Department of Biostatistics (Y.S., M.X., F.E.H.), Division of Clinical Pharmacology, Department of Medicine (D.M.R., C.M.S.), Division of Cardiac Surgery, Department of Surgery (T.A.), Division of Cardiovascular Medicine (T. N., E. C., Y.R.S., D.R., C.L.G., Q.S.W, R.J.G.), Department of Pharmacology and Department of Pathology, Immunology, and Microbiology (R.J.G.), Vanderbilt University Medical Center, Nashville, TN
| | - Mark J Kohr
- From the Division of Cardiovascular Medicine, Davis Heart and Lung Research Institute (B.Z., D.G.W., Z.X., R.H., H.H., S.V., J.L.Z.), Department of Physiology and Cell Biology (B.Z., J.L.Z., M.J.K., M.T.Z.), The Ohio State University, Columbus; Institute of Organ Transplantation, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, HuBei, China (B.Z.); Department of Biostatistics (Y.S., M.X., F.E.H.), Division of Clinical Pharmacology, Department of Medicine (D.M.R., C.M.S.), Division of Cardiac Surgery, Department of Surgery (T.A.), Division of Cardiovascular Medicine (T. N., E. C., Y.R.S., D.R., C.L.G., Q.S.W, R.J.G.), Department of Pharmacology and Department of Pathology, Immunology, and Microbiology (R.J.G.), Vanderbilt University Medical Center, Nashville, TN
| | - Mark T Ziolo
- From the Division of Cardiovascular Medicine, Davis Heart and Lung Research Institute (B.Z., D.G.W., Z.X., R.H., H.H., S.V., J.L.Z.), Department of Physiology and Cell Biology (B.Z., J.L.Z., M.J.K., M.T.Z.), The Ohio State University, Columbus; Institute of Organ Transplantation, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, HuBei, China (B.Z.); Department of Biostatistics (Y.S., M.X., F.E.H.), Division of Clinical Pharmacology, Department of Medicine (D.M.R., C.M.S.), Division of Cardiac Surgery, Department of Surgery (T.A.), Division of Cardiovascular Medicine (T. N., E. C., Y.R.S., D.R., C.L.G., Q.S.W, R.J.G.), Department of Pharmacology and Department of Pathology, Immunology, and Microbiology (R.J.G.), Vanderbilt University Medical Center, Nashville, TN
| | - Dan M Roden
- From the Division of Cardiovascular Medicine, Davis Heart and Lung Research Institute (B.Z., D.G.W., Z.X., R.H., H.H., S.V., J.L.Z.), Department of Physiology and Cell Biology (B.Z., J.L.Z., M.J.K., M.T.Z.), The Ohio State University, Columbus; Institute of Organ Transplantation, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, HuBei, China (B.Z.); Department of Biostatistics (Y.S., M.X., F.E.H.), Division of Clinical Pharmacology, Department of Medicine (D.M.R., C.M.S.), Division of Cardiac Surgery, Department of Surgery (T.A.), Division of Cardiovascular Medicine (T. N., E. C., Y.R.S., D.R., C.L.G., Q.S.W, R.J.G.), Department of Pharmacology and Department of Pathology, Immunology, and Microbiology (R.J.G.), Vanderbilt University Medical Center, Nashville, TN
| | - Christian M Shaffer
- From the Division of Cardiovascular Medicine, Davis Heart and Lung Research Institute (B.Z., D.G.W., Z.X., R.H., H.H., S.V., J.L.Z.), Department of Physiology and Cell Biology (B.Z., J.L.Z., M.J.K., M.T.Z.), The Ohio State University, Columbus; Institute of Organ Transplantation, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, HuBei, China (B.Z.); Department of Biostatistics (Y.S., M.X., F.E.H.), Division of Clinical Pharmacology, Department of Medicine (D.M.R., C.M.S.), Division of Cardiac Surgery, Department of Surgery (T.A.), Division of Cardiovascular Medicine (T. N., E. C., Y.R.S., D.R., C.L.G., Q.S.W, R.J.G.), Department of Pharmacology and Department of Pathology, Immunology, and Microbiology (R.J.G.), Vanderbilt University Medical Center, Nashville, TN
| | - Cristi L Galindo
- From the Division of Cardiovascular Medicine, Davis Heart and Lung Research Institute (B.Z., D.G.W., Z.X., R.H., H.H., S.V., J.L.Z.), Department of Physiology and Cell Biology (B.Z., J.L.Z., M.J.K., M.T.Z.), The Ohio State University, Columbus; Institute of Organ Transplantation, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, HuBei, China (B.Z.); Department of Biostatistics (Y.S., M.X., F.E.H.), Division of Clinical Pharmacology, Department of Medicine (D.M.R., C.M.S.), Division of Cardiac Surgery, Department of Surgery (T.A.), Division of Cardiovascular Medicine (T. N., E. C., Y.R.S., D.R., C.L.G., Q.S.W, R.J.G.), Department of Pharmacology and Department of Pathology, Immunology, and Microbiology (R.J.G.), Vanderbilt University Medical Center, Nashville, TN
| | - Quinn S Wells
- From the Division of Cardiovascular Medicine, Davis Heart and Lung Research Institute (B.Z., D.G.W., Z.X., R.H., H.H., S.V., J.L.Z.), Department of Physiology and Cell Biology (B.Z., J.L.Z., M.J.K., M.T.Z.), The Ohio State University, Columbus; Institute of Organ Transplantation, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, HuBei, China (B.Z.); Department of Biostatistics (Y.S., M.X., F.E.H.), Division of Clinical Pharmacology, Department of Medicine (D.M.R., C.M.S.), Division of Cardiac Surgery, Department of Surgery (T.A.), Division of Cardiovascular Medicine (T. N., E. C., Y.R.S., D.R., C.L.G., Q.S.W, R.J.G.), Department of Pharmacology and Department of Pathology, Immunology, and Microbiology (R.J.G.), Vanderbilt University Medical Center, Nashville, TN
| | - Richard J Gumina
- From the Division of Cardiovascular Medicine, Davis Heart and Lung Research Institute (B.Z., D.G.W., Z.X., R.H., H.H., S.V., J.L.Z.), Department of Physiology and Cell Biology (B.Z., J.L.Z., M.J.K., M.T.Z.), The Ohio State University, Columbus; Institute of Organ Transplantation, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, HuBei, China (B.Z.); Department of Biostatistics (Y.S., M.X., F.E.H.), Division of Clinical Pharmacology, Department of Medicine (D.M.R., C.M.S.), Division of Cardiac Surgery, Department of Surgery (T.A.), Division of Cardiovascular Medicine (T. N., E. C., Y.R.S., D.R., C.L.G., Q.S.W, R.J.G.), Department of Pharmacology and Department of Pathology, Immunology, and Microbiology (R.J.G.), Vanderbilt University Medical Center, Nashville, TN.
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6
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Feng Y, Liu J, Wang M, Liu M, Shi L, Yuan W, Ye J, Hu D, Wan J. The E23K variant of the Kir6.2 subunit of the ATP-sensitive potassium channel increases susceptibility to ventricular arrhythmia in response to ischemia in rats. Int J Cardiol 2017; 232:192-198. [DOI: 10.1016/j.ijcard.2017.01.022] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Revised: 12/27/2016] [Accepted: 01/03/2017] [Indexed: 12/22/2022]
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7
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Abstract
Cardiac arrhythmias can follow disruption of the normal cellular electrophysiological processes underlying excitable activity and their tissue propagation as coherent wavefronts from the primary sinoatrial node pacemaker, through the atria, conducting structures and ventricular myocardium. These physiological events are driven by interacting, voltage-dependent, processes of activation, inactivation, and recovery in the ion channels present in cardiomyocyte membranes. Generation and conduction of these events are further modulated by intracellular Ca2+ homeostasis, and metabolic and structural change. This review describes experimental studies on murine models for known clinical arrhythmic conditions in which these mechanisms were modified by genetic, physiological, or pharmacological manipulation. These exemplars yielded molecular, physiological, and structural phenotypes often directly translatable to their corresponding clinical conditions, which could be investigated at the molecular, cellular, tissue, organ, and whole animal levels. Arrhythmogenesis could be explored during normal pacing activity, regular stimulation, following imposed extra-stimuli, or during progressively incremented steady pacing frequencies. Arrhythmic substrate was identified with temporal and spatial functional heterogeneities predisposing to reentrant excitation phenomena. These could arise from abnormalities in cardiac pacing function, tissue electrical connectivity, and cellular excitation and recovery. Triggering events during or following recovery from action potential excitation could thereby lead to sustained arrhythmia. These surface membrane processes were modified by alterations in cellular Ca2+ homeostasis and energetics, as well as cellular and tissue structural change. Study of murine systems thus offers major insights into both our understanding of normal cardiac activity and its propagation, and their relationship to mechanisms generating clinical arrhythmias.
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Affiliation(s)
- Christopher L-H Huang
- Physiological Laboratory and the Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
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8
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Roy Chowdhury U, Dosa PI, Fautsch MP. ATP sensitive potassium channel openers: A new class of ocular hypotensive agents. Exp Eye Res 2016; 158:85-93. [PMID: 27130546 DOI: 10.1016/j.exer.2016.04.020] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Revised: 04/22/2016] [Accepted: 04/25/2016] [Indexed: 12/25/2022]
Abstract
ATP sensitive potassium (KATP) channels connect the metabolic and energetic state of cells due to their sensitivity to ATP and ADP concentrations. KATP channels have been identified in multiple tissues and organs of the body including heart, pancreas, vascular smooth muscles and skeletal muscles. These channels are obligatory hetero-octamers and contain four sulfonylurea (SUR) and four potassium inward rectifier (Kir) subunits. Based on the particular type of SUR and Kir present, there are several tissue specific subtypes of KATP channels, each with their own unique set of functions. Recently, KATP channels have been reported in human and mouse ocular tissues. In ex vivo and in vivo model systems, KATP channel openers showed significant ocular hypotensive properties with no appearance of toxic side effects. Additionally, when used in conjunction with known intraocular pressure lowering drugs, an additive effect on IOP reduction was observed. These KATP channel openers have also been reported to protect the retinal ganglion cells during ischemic stress and glutamate induced toxicity suggesting a neuroprotective property for this drug class. Medications that are currently used for treating ocular hypertensive diseases like glaucoma do not directly protect the affected retinal cells, are sometimes ineffective and may show significant side effects. In light of this, KATP channel openers with both ocular hypotensive and neuroprotective properties, have the potential to develop into a new class of glaucoma therapeutics.
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Affiliation(s)
- Uttio Roy Chowdhury
- Dept. of Ophthalmology, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, United States.
| | - Peter I Dosa
- Institute for Therapeutics Discovery and Development, Department of Medicinal Chemistry, University of Minnesota, 717 Delaware Street SE, Minneapolis, MN 55414, United States.
| | - Michael P Fautsch
- Dept. of Ophthalmology, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, United States.
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9
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Gao Z, Sierra A, Zhu Z, Koganti SRK, Subbotina E, Maheshwari A, Anderson ME, Zingman LV, Hodgson-Zingman DM. Loss of ATP-Sensitive Potassium Channel Surface Expression in Heart Failure Underlies Dysregulation of Action Potential Duration and Myocardial Vulnerability to Injury. PLoS One 2016; 11:e0151337. [PMID: 26964104 PMCID: PMC4786327 DOI: 10.1371/journal.pone.0151337] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2015] [Accepted: 02/26/2016] [Indexed: 11/18/2022] Open
Abstract
The search for new approaches to treatment and prevention of heart failure is a major challenge in medicine. The adenosine triphosphate-sensitive potassium (KATP) channel has been long associated with the ability to preserve myocardial function and viability under stress. High surface expression of membrane KATP channels ensures a rapid energy-sparing reduction in action potential duration (APD) in response to metabolic challenges, while cellular signaling that reduces surface KATP channel expression blunts APD shortening, thus sacrificing energetic efficiency in exchange for greater cellular calcium entry and increased contractile force. In healthy hearts, calcium/calmodulin-dependent protein kinase II (CaMKII) phosphorylates the Kir6.2 KATP channel subunit initiating a cascade responsible for KATP channel endocytosis. Here, activation of CaMKII in a transaortic banding (TAB) model of heart failure is coupled with a 35–40% reduction in surface expression of KATP channels compared to hearts from sham-operated mice. Linkage between KATP channel expression and CaMKII is verified in isolated cardiomyocytes in which activation of CaMKII results in downregulation of KATP channel current. Accordingly, shortening of monophasic APD is slowed in response to hypoxia or heart rate acceleration in failing compared to non-failing hearts, a phenomenon previously shown to result in significant increases in oxygen consumption. Even in the absence of coronary artery disease, failing myocardium can be further injured by ischemia due to a mismatch between metabolic supply and demand. Ischemia-reperfusion injury, following ischemic preconditioning, is diminished in hearts with CaMKII inhibition compared to wild-type hearts and this advantage is largely eliminated when myocardial KATP channel expression is absent, supporting that the myocardial protective benefit of CaMKII inhibition in heart failure may be substantially mediated by KATP channels. Recognition of CaMKII-dependent downregulation of KATP channel expression as a mechanism for vulnerability to injury in failing hearts points to strategies targeting this interaction for potential preventives or treatments.
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Affiliation(s)
- Zhan Gao
- Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, Iowa, United States of America
| | - Ana Sierra
- Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, Iowa, United States of America
| | - Zhiyong Zhu
- Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, Iowa, United States of America
| | - Siva Rama Krishna Koganti
- Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, Iowa, United States of America
| | - Ekaterina Subbotina
- Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, Iowa, United States of America
| | - Ankit Maheshwari
- Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, Iowa, United States of America
| | - Mark E. Anderson
- Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, Iowa, United States of America
- François Abboud Cardiovascular Research Center, University of Iowa, Iowa City, Iowa, United States of America
| | - Leonid V. Zingman
- Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, Iowa, United States of America
- François Abboud Cardiovascular Research Center, University of Iowa, Iowa City, Iowa, United States of America
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, Iowa, United States of America
- Veterans Affairs Medical Center, Iowa City, Iowa, United States of America
| | - Denice M. Hodgson-Zingman
- Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, Iowa, United States of America
- François Abboud Cardiovascular Research Center, University of Iowa, Iowa City, Iowa, United States of America
- * E-mail:
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10
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Abstract
KATP channels are integral to the functions of many cells and tissues. The use of electrophysiological methods has allowed for a detailed characterization of KATP channels in terms of their biophysical properties, nucleotide sensitivities, and modification by pharmacological compounds. However, even though they were first described almost 25 years ago (Noma 1983, Trube and Hescheler 1984), the physiological and pathophysiological roles of these channels, and their regulation by complex biological systems, are only now emerging for many tissues. Even in tissues where their roles have been best defined, there are still many unanswered questions. This review aims to summarize the properties, molecular composition, and pharmacology of KATP channels in various cardiovascular components (atria, specialized conduction system, ventricles, smooth muscle, endothelium, and mitochondria). We will summarize the lessons learned from available genetic mouse models and address the known roles of KATP channels in cardiovascular pathologies and how genetic variation in KATP channel genes contribute to human disease.
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Affiliation(s)
- Monique N Foster
- Departments of Pediatrics, Physiology & Neuroscience, and Biochemistry and Molecular Pharmacology, NYU School of Medicine, New York, New York
| | - William A Coetzee
- Departments of Pediatrics, Physiology & Neuroscience, and Biochemistry and Molecular Pharmacology, NYU School of Medicine, New York, New York
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11
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Brennan S, Jackson R, Patel M, Sims MW, Hudman D, Norman RI, Lodwick D, Rainbow RD. Early opening of sarcolemmal ATP-sensitive potassium channels is not a key step in PKC-mediated cardioprotection. J Mol Cell Cardiol 2014; 79:42-53. [PMID: 25450614 DOI: 10.1016/j.yjmcc.2014.10.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/13/2014] [Revised: 09/29/2014] [Accepted: 10/20/2014] [Indexed: 11/29/2022]
Abstract
ATP-sensitive potassium (KATP) channels are abundantly expressed in the myocardium. Although a definitive role for the channel remains elusive they have been implicated in the phenomenon of cardioprotection, but the precise mechanism is unclear. We set out to test the hypothesis that the channel protects by opening early during ischemia to shorten action potential duration and reduce electrical excitability thus sparing intracellular ATP. This could reduce reperfusion injury by improving calcium homeostasis. Using a combination of contractile function analysis, calcium fluorescence imaging and patch clamp electrophysiology in cardiomyocytes isolated from adult male Wistar rats, we demonstrated that the opening of sarcolemmal KATP channels was markedly delayed after cardioprotective treatments: ischemic preconditioning, adenosine and PMA. This was due to the preservation of intracellular ATP for longer during simulated ischemia therefore maintaining sarcolemmal KATP channels in the closed state for longer. As the simulated ischemia progressed, KATP channels opened to cause contractile, calcium transient and action potential failure; however there was no indication of any channel activity early during simulated ischemia to impart an energy sparing hyperpolarization or action potential shortening. We present compelling evidence to demonstrate that an early opening of sarcolemmal KATP channels during simulated ischemia is not part of the protective mechanism imparted by ischemic preconditioning or other PKC-dependent cardioprotective stimuli. On the contrary, channel opening was actually delayed. We conclude that sarcolemmal KATP channel opening is a consequence of ATP depletion, not a primary mechanism of ATP preservation in these cells.
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Affiliation(s)
- Sean Brennan
- Department of Cardiovascular Sciences, University of Leicester, Clinical Sciences Wing, Glenfield General Hospital, Leicester, LE3 9QP, UK
| | - Robert Jackson
- Department of Cardiovascular Sciences, University of Leicester, Clinical Sciences Wing, Glenfield General Hospital, Leicester, LE3 9QP, UK
| | - Manish Patel
- Department of Cardiovascular Sciences, University of Leicester, Clinical Sciences Wing, Glenfield General Hospital, Leicester, LE3 9QP, UK
| | - Mark W Sims
- Department of Cardiovascular Sciences, University of Leicester, Clinical Sciences Wing, Glenfield General Hospital, Leicester, LE3 9QP, UK
| | - Diane Hudman
- Department of Medical and Social Care Education, Maurice Shock Medical Sciences Building, University of Leicester, Leicester, LE1 9HN, UK
| | - Robert I Norman
- Department of Medical and Social Care Education, Maurice Shock Medical Sciences Building, University of Leicester, Leicester, LE1 9HN, UK
| | - David Lodwick
- Department of Cardiovascular Sciences, University of Leicester, Clinical Sciences Wing, Glenfield General Hospital, Leicester, LE3 9QP, UK
| | - Richard D Rainbow
- Department of Cardiovascular Sciences, University of Leicester, Clinical Sciences Wing, Glenfield General Hospital, Leicester, LE3 9QP, UK.
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12
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Fedele F, Severino P, Bruno N, Stio R, Caira C, D'Ambrosi A, Brasolin B, Ohanyan V, Mancone M. Role of ion channels in coronary microcirculation: a review of the literature. Future Cardiol 2014; 9:897-905. [PMID: 24180545 DOI: 10.2217/fca.13.65] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
In normal coronary arteries, several different mechanisms of blood flow regulation exist, acting at different levels of the coronary tree: endothelial, nervous, myogenic and metabolic regulation. In addition, physiologic blood flow regulation is also dependent on the activity of several coronary ion channels, including ATP-dependent K(+) channels, voltage-gated K(+) channels and others. In this context, ion channels contribute by matching demands for homeostatic maintenance. They play a primary role in rapid response of both endothelium and vascular smooth muscle cells of larger and smaller arterial vessels of the coronary bed, leading to coronary vasodilation. Consequently, an alteration in ion channel function or expression could be directly involved in coronary vasomotion dysfunction.
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Affiliation(s)
- Francesco Fedele
- Department of Cardiovascular, Respiratory, Nephrology, Anesthesiology & Geriatric Sciences, Sapienza University, Policlinico Umberto I, Rome, Italy
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13
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Lee HL, Lu CH, Chang PC, Chou CC, Wo HT, Wen MS. Contrasting effects of HMR1098 on arrhythmogenicity in a Langendorff-perfused phase-2 myocardial infarction rabbit model. Pacing Clin Electrophysiol 2014; 37:1058-66. [PMID: 24645834 DOI: 10.1111/pace.12381] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/12/2013] [Revised: 01/05/2014] [Accepted: 01/28/2014] [Indexed: 11/30/2022]
Abstract
BACKGROUND The stability of dynamic factors has been reported to play a role in the antiarrhythmic actions of adenosine triphosphate (ATP)-sensitive potassium channel (KATP) opener in phase-2 myocardial infarction (MI) hearts. In the situation of the downregulation of KATP, the effects of KATP blocker (HMR1098) on the dynamic factors and electrophysiological changes during phase-2 MI remain unclear. METHODS Dual voltage and intracellular Ca(2+) (Cai) optical mapping was performed in nine Langendorff-perfused hearts 4-5 hours after coronary artery ligation and five control hearts. Electrophysiology studies, including action potential duration (APD) restitution, conduction velocity (CV), inducibility of ventricular fibrillation (VF), VF dominant frequency, APD and Cai alternans, and Cai decay, were performed. The same protocol was repeated in the presence of HMR1098 (10 μm) after the baseline studies. RESULTS HMR1098 significantly prolonged APD and effective refractory period to prevent sustained VF in five of nine MI hearts and two of five control hearts compared to none at baseline in both groups. On the other hand, HMR1098 steepened APD restitution slope to enhance spatially concordant alternans in both groups. In the phase-2 MI group, HMR1098 steepened CV restitution slope and enhanced spatially discordant alternans (SDA), which might account for a decreased pacing threshold of VF induction during HMR1098 infusion in phase-2 MI hearts. CONCLUSIONS In phase-2 MI hearts, HMR1098 has contrasting effects on arrhythmogenesis, suppressing reentry and VF persistence but facilitating VF inducibility. The mechanism is the intensified induction of SDA because of the steepened APD and CV restitution slopes.
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Affiliation(s)
- Hui-Ling Lee
- Department of Anesthesia, Chang Gung Memorial Hospital, Taipei, Taiwan
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14
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Csonka C, Kupai K, Bencsik P, Görbe A, Pálóczi J, Zvara A, Puskás LG, Csont T, Ferdinandy P. Cholesterol-enriched diet inhibits cardioprotection by ATP-sensitive K+ channel activators cromakalim and diazoxide. Am J Physiol Heart Circ Physiol 2013; 306:H405-13. [PMID: 24285110 DOI: 10.1152/ajpheart.00257.2013] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
It has been previously shown that hyperlipidemia interferes with cardioprotective mechanisms. Here, we investigated the interaction of hyperlipidemia with cardioprotection induced by pharmacological activators of ATP-sensitive K(+) (KATP) channels. Hearts isolated from rats fed a 2% cholesterol-enriched diet or normal diet for 8 wk were subjected to 30 min of global ischemia and 120 min of reperfusion in the presence or absence of KATP modulators. In normal diet-fed rats, either the nonselective KATP activator cromakalim at 10(-5) M or the selective mitochondrial (mito)KATP opener diazoxide at 3 × 10(-5) M significantly decreased infarct size compared with vehicle-treated control rats. Their cardioprotective effect was abolished by coadministration of the nonselective KATP blocker glibenclamide or the selective mitoKATP blocker 5-hydroxydecanoate, respectively. However, in cholesterol-fed rats, the cardioprotective effect of cromakalim or diazoxide was not observed. Therefore, we further investigated how cholesterol-enriched diet influences cardiac KATP channels. Cardiac expression of a KATP subunit gene (Kir6.1) was significantly downregulated in cholesterol-fed rats; however, protein levels of Kir6.1 and Kir6.2 were not changed. The cholesterol diet significantly decreased cardiac ATP, increased lactate content, and enhanced myocardial oxidative stress, as shown by increased cardiac superoxide and dityrosine formation. This is the first demonstration that cardioprotection by KATP channel activators is impaired in cholesterol-enriched diet-induced hyperlipidemia. The background mechanism may include hyperlipidemia-induced attenuation of mitoKATP function by altered energy metabolism and increased oxidative stress in the heart.
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Affiliation(s)
- Csaba Csonka
- Cardiovascular Research Group, Department of Biochemistry, University of Szeged, Szeged, Hungary
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15
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Zafalon N, Oshiyama NF, Bassani JWM, Bassani RA. Muscarinic stimulation and pinacidil produce similar facilitation of tachyarrhythmia induction in rat isolated atria. J Mol Cell Cardiol 2013; 65:120-6. [PMID: 24140800 DOI: 10.1016/j.yjmcc.2013.10.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Accepted: 10/09/2013] [Indexed: 10/26/2022]
Abstract
Atrial tachyarrhythmias, the most common type of cardiac arrhythmias, are associated with greater stroke risk. Muscarinic cholinergic agonists have been shown to facilitate atrial tachyarrhythmia maintenance in the absence of cardiac disease. This has been attributed to action potential shortening, which enhances myocardial electrical anisotropy, and thus creates a substrate for reentrant excitation. In this study, we describe a similar effect of the ATP-sensitive K(+) channel (KATP) opener pinacidil on tachyarrhythmia induction in isolated rat atria. Pinacidil, which activates a weakly inwardly-rectifying current in isolated atrial myocytes, enhanced arrhythmia induction in the right and left atria. This effect was abolished by the KATP blocker glibenclamide, but not by atropine, which rules out a possible indirect effect due to stimulation of acetylcholine release. However, pinacidil attenuated carbachol-induced tachyarrhythmia facilitation, which may indicate that the action of these agonists converges to a common cellular mechanism. Both agonists caused marked action potential shortening in isolated atrial myocytes. Moreover, during arrhythmia in the presence of pinacidil and carbachol, the atrial vectorelectrographic patterns were similar and consistent with reentrant propagation of the electrical activity. From these results, we conclude that the KATP channel opening is pro-arrhythmic in atrial tissue, which may pose as an additional risk in the scenario of myocardial hypoxia. Moreover, the similarity of the electrophysiological effects of pinacidil and carbachol is suggestive that the sole increase in background K(+) conductance is sufficient for atrial tachyarrhythmia facilitation.
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Affiliation(s)
- Nivaldo Zafalon
- Department of Biomedical Engineering/FEEC, University of Campinas, Caixa Postal 6040, 13084-971 Campinas, SP, Brazil.
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16
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Role of genetic polymorphisms of ion channels in the pathophysiology of coronary microvascular dysfunction and ischemic heart disease. Basic Res Cardiol 2013; 108:387. [PMID: 24068186 PMCID: PMC3898136 DOI: 10.1007/s00395-013-0387-4] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/27/2013] [Revised: 08/13/2013] [Accepted: 09/11/2013] [Indexed: 01/14/2023]
Abstract
Conventionally, ischemic heart disease (IHD) is equated with large vessel coronary disease. However, recent evidence has suggested a role of compromised microvascular regulation in the etiology of IHD. Because regulation of coronary blood flow likely involves activity of specific ion channels, and key factors involved in endothelium-dependent dilation, we proposed that genetic anomalies of ion channels or specific endothelial regulators may underlie coronary microvascular disease. We aimed to evaluate the clinical impact of single-nucleotide polymorphisms in genes encoding for ion channels expressed in the coronary vasculature and the possible correlation with IHD resulting from microvascular dysfunction. 242 consecutive patients who were candidates for coronary angiography were enrolled. A prospective, observational, single-center study was conducted, analyzing genetic polymorphisms relative to (1) NOS3 encoding for endothelial nitric oxide synthase (eNOS); (2) ATP2A2 encoding for the Ca2+/H+-ATPase pump (SERCA); (3) SCN5A encoding for the voltage-dependent Na+ channel (Nav1.5); (4) KCNJ8 and KCNJ11 encoding for the Kir6.1 and Kir6.2 subunits of K-ATP channels, respectively; and (5) KCN5A encoding for the voltage-gated K+ channel (Kv1.5). No significant associations between clinical IHD manifestations and polymorphisms for SERCA, Kir6.1, and Kv1.5 were observed (p > 0.05), whereas specific polymorphisms detected in eNOS, as well as in Kir6.2 and Nav1.5 were found to be correlated with IHD and microvascular dysfunction. Interestingly, genetic polymorphisms for ion channels seem to have an important clinical impact influencing the susceptibility for microvascular dysfunction and IHD, independent of the presence of classic cardiovascular risk factors.
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17
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Muravyeva M, Sedlic F, Dolan N, Bosnjak ZJ, Stadnicka A. Preconditioning by isoflurane elicits mitochondrial protective mechanisms independent of sarcolemmal KATP channel in mouse cardiomyocytes. J Cardiovasc Pharmacol 2013; 61:369-77. [PMID: 23318991 PMCID: PMC3648596 DOI: 10.1097/fjc.0b013e318285f55b] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Cardiac mitochondria and the sarcolemmal (sarc)KATP channels contribute to cardioprotective signaling of anesthetic-induced preconditioning. Changes in mitochondrial bioenergetics influence the sarcolemmal ATP-sensitive K (sarcKATP) channel function, but whether this channel has impacts on mitochondria is uncertain. We used the mouse model with deleted pore-forming Kir6.2 subunit of sarcKATP channel (Kir6.2 KO) to investigate whether the functional sarcKATP channels are necessary for isoflurane activation of mitochondrial protective mechanisms. Ventricular cardiomyocytes were isolated from C57Bl6 wild-type (WT) and Kir6.2 KO mouse hearts. Flavoprotein autofluorescence, mitochondrial reactive oxygen species production, and mitochondrial membrane potential were monitored by laser-scanning confocal microscopy in intact cardiomyocytes. Cell survival was assessed using H2O2-induced stress. Isoflurane (0.5 mM) increased flavoprotein fluorescence to 180% ± 14% and 190% ± 15% and reactive oxygen species production to 118% ± 2% and 124% ± 6% of baseline in WT and Kir6.2 KO myocytes, respectively. Tetramethylrhodamine ethyl ester fluorescence decreased to 84% ± 6% in WT and to 86% ± 4% in Kir6.2 KO myocytes. This effect was abolished by 5HD. Pretreatment with isoflurane decreased the stress-induced cell death from 31% ± 1% to 21% ± 1% in WT and from 44% ± 2% to 35% ± 2% in Kir6.2 KO myocytes. In conclusion, Kir6.2 deletion increases the sensitivity of intact cardiomyocytes to oxidative stress, but does not alter the isoflurane-elicited protective mitochondrial mechanisms, suggesting independent roles for cardiac mitochondria and sarcKATP channels in anesthetic-induced preconditioning by isoflurane.
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Affiliation(s)
- Maria Muravyeva
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI 53226, USA
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18
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Functional roles of KATP channel subunits in metabolic inhibition. J Mol Cell Cardiol 2013; 62:90-8. [PMID: 23624089 DOI: 10.1016/j.yjmcc.2013.04.016] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2012] [Revised: 03/11/2013] [Accepted: 04/15/2013] [Indexed: 11/23/2022]
Abstract
ATP-sensitive potassium channel (KATP) activation can drastically shorten action potential duration (APD) in metabolically compromised myocytes. We showed previously that SUR1 with Kir6.2 forms the functional channel in mouse atria while Kir6.2 and SUR2A predominate in ventricles. SUR1 is more sensitive to metabolic stress than SUR2A, raising the possibility that KATP in atria and ventricles may respond differently to metabolic stress. Action potential duration (APD) and calcium transient duration (CaTD) were measured simultaneously in both atria and ventricles by optical mapping of the posterior surface of Langendorff-perfused hearts from C57BL wild-type (WT; n=11), Kir6.2(-/-) (n=5), and SUR1(-/-) (n=6) mice during metabolic inhibition (MI, 0mM glucose+2mM sodium cyanide). After variable delay, MI led to significant shortening of APD in WT hearts. On average, atrial APD shortened by 60.5 ± 2.7% at 13.1 ± 2.1 min (n=6, p<0.01) after onset of MI. Ventricular APD shortening (56.4 ± 10.0% shortening at 18.2 ± 1.8 min) followed atrial APD shortening. In SUR1(-/-) hearts (n=6), atrial APD shortening was abolished, but ventricular shortening (65.0 ± 15.4% at 25.33 ± 4.48 min, p<0.01) was unaffected. In Kir6.2(-/-) hearts, two disparate responses to MI were observed; 3 of 5 hearts displayed slight shortening of APD in the ventricles (24 ± 3%, p<0.05) and atria (39.0 ± 1.9%, p<0.05) but this shortening occurred later and to much less extent than in WT (p<0.05). Marked prolongation of ventricular APD was observed in the remaining hearts (327% and 489% prolongation) and was associated with occurrence of ventricular tachyarrhythmias. The results confirm that Kir6.2 contributes to APD shortening in both atria and ventricle during metabolic stress, and that SUR1 is required for atrial APD shortening while SUR2A is required for ventricular APD shortening. Importantly, the results show that the presence of SUR1-dependent KATP in the atria results in the action potential being more susceptible to metabolically driven shortening than the ventricle.
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19
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Wojtovich AP, Urciuoli WR, Chatterjee S, Fisher AB, Nehrke K, Brookes PS. Kir6.2 is not the mitochondrial KATP channel but is required for cardioprotection by ischemic preconditioning. Am J Physiol Heart Circ Physiol 2013; 304:H1439-45. [PMID: 23585131 DOI: 10.1152/ajpheart.00972.2012] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
ATP-sensitive K(+) (KATP) channels that contain K(+) inward rectifier subunits of the 6.2 isotype (Kir6.2) are important regulators of the cardiac response to ischemia-reperfusion (I/R) injury. Opening of these channels is implicated in the cardioprotective mechanism of ischemic preconditioning (IPC), but debate surrounds the contribution of surface KATP (sKATP) versus mitochondrial KATP (mKATP) channels. While responses to I/R injury and IPC have been examined in Kir6.2(-/-) mice before, breeding methods and other technical obstacles may have confounded interpretations. The aim of this study was to elucidate the role of Kir6.2 in cardioprotection and mKATP activity, using conventionally bred Kir6.2(-/-) mice with wild-type littermates as controls. We found that perfused hearts from Kir6.2(-/-) mice exhibited a normal baseline response to I/R injury, were not protected by IPC, and showed a blunted response to the IPC mimetic drug diazoxide. These data suggest that the loss of IPC in Kir6.2(-/-) hearts is not due to an underlying difference in I/R sensitivity. Furthermore, mKATP channel activity was identical in cardiac mitochondria isolated from wild-type versus Kir6.2(-/-) mice, suggesting no role for Kir6.2 in the mKATP. Collectively, these data indicate that Kir6.2 is required for the full response to IPC or diazoxide but is not involved in mKATP formation.
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Affiliation(s)
- Andrew P Wojtovich
- Department of Medicine, University of Rochester Medical Center, Rochester, NY, USA
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20
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Abstract
Previous studies have indicated that estrogen protects the brain from ischemic damage and regulates K(ATP) channel activity; the present study was designed to address the involvement of K(ATP) channels in the neuroprotective effects of estrogen in focal cerebral ischemia: in experiment 1, K(ATP) mRNA and protein in the cortices of rats were compared among groups of ovariectomized rats (Ovx-1), Sham-operated rats (Sham-1), and ovariectomized rats administered 17β-estradiol (Estr-1). In experiment 2, neurobehavioral scores and infarct volume of rats were evaluated after middle cerebral artery occlusion in ovariectomized rats (Ovx-2), Sham-operated rats (Sham-2), ovariectomized female rats administered 17β-estradiol (Estr-2), and ovariectomized rats administered both 17β-estradiol and stereotactic injections of glibenclamide (Estr+G). Our results showed that the Kir6.2 and SUR1 mRNA and protein levels in the brain cortices of female ovariectomized rats were lower than those in Sham rats. However, the expression levels of Kir6.2 and SUR1 in brain cortices of ovariectomized rats recovered after supplementation with 17β-estradiol. The protective effects of 17β-estradiol were abolished by glibenclamide, a K(ATP) channel blocker. This indicates that estradiol significantly upregulates the expression of K(ATP) channel subunits and channel activity in the brain cortices of ovariectomized rats. This regulation is associated with the neuroprotective effects of estradiol.
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LEE HUILING, CHANG POCHENG, CHOU CHUNGCHUAN, WO HUNGTA, CHU YEN, WEN MINGSHIEN, YEH SANJOU, WU DELON. Blunted Proarrhythmic Effect of Nicorandil in a Langendorff-Perfused Phase-2 Myocardial Infarction Rabbit Model. PACING AND CLINICAL ELECTROPHYSIOLOGY: PACE 2012; 36:142-51. [DOI: 10.1111/pace.12029] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2012] [Revised: 08/17/2012] [Accepted: 08/21/2012] [Indexed: 11/29/2022]
Affiliation(s)
- HUI-LING LEE
- Department of Anesthesia; Chang Gung Memorial Hospital; Taipei; Taiwan
| | | | | | - HUNG-TA WO
- Second Section of Cardiology; Department of Medicine
| | - YEN CHU
- Division of Thoracic Surgery; Chang Gung Memorial Hospital, Linkou, Taiwan; Chang Gung University College of Medicine; Taoyuan; Taiwan
| | | | - SAN-JOU YEH
- Second Section of Cardiology; Department of Medicine
| | - DELON WU
- Second Section of Cardiology; Department of Medicine
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22
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Nemutlu E, Zhang S, Gupta A, Juranic NO, Macura SI, Terzic A, Jahangir A, Dzeja P. Dynamic phosphometabolomic profiling of human tissues and transgenic models by 18O-assisted ³¹P NMR and mass spectrometry. Physiol Genomics 2012; 44:386-402. [PMID: 22234996 DOI: 10.1152/physiolgenomics.00152.2011] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Next-generation screening of disease-related metabolomic phenotypes requires monitoring of both metabolite levels and turnover rates. Stable isotope (18)O-assisted (31)P nuclear magnetic resonance (NMR) and mass spectrometry uniquely allows simultaneous measurement of phosphometabolite levels and turnover rates in tissue and blood samples. The (18)O labeling procedure is based on the incorporation of one (18)O into P(i) from [(18)O]H(2)O with each act of ATP hydrolysis and the distribution of (18)O-labeled phosphoryls among phosphate-carrying molecules. This enables simultaneous recording of ATP synthesis and utilization, phosphotransfer fluxes through adenylate kinase, creatine kinase, and glycolytic pathways, as well as mitochondrial substrate shuttle, urea and Krebs cycle activity, glycogen turnover, and intracellular energetic communication. Application of expanded (18)O-labeling procedures has revealed significant differences in the dynamics of G-6-P[(18)O] (glycolysis), G-3-P[(18)O] (substrate shuttle), and G-1-P[(18)O] (glycogenolysis) between human and rat atrial myocardium. In human atria, the turnover of G-3-P[(18)O], which defects are associated with the sudden death syndrome, was significantly higher indicating a greater importance of substrate shuttling to mitochondria. Phosphometabolomic profiling of transgenic hearts deficient in adenylate kinase (AK1-/-), which altered levels and mutations are associated to human diseases, revealed a stress-induced shift in metabolomic profile with increased CrP[(18)O] and decreased G-1-P[(18)O] metabolic dynamics. The metabolomic profile of creatine kinase M-CK/ScCKmit-/--deficient hearts is characterized by a higher G-6-[(18)O]P turnover rate, G-6-P levels, glycolytic capacity, γ/β-phosphoryl of GTP[(18)O] turnover, as well as β-[(18)O]ATP and β-[(18)O]ADP turnover, indicating altered glycolytic, guanine nucleotide, and adenylate kinase metabolic flux. Thus, (18)O-assisted gas chromatography-mass spectrometry and (31)P NMR provide a suitable platform for dynamic phosphometabolomic profiling of the cellular energetic system enabling prediction and diagnosis of metabolic diseases states.
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Affiliation(s)
- Emirhan Nemutlu
- Division of Cardiovascular Diseases, Department of Medicine, Mayo Clinic, Rochester, Minnesota, USA
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23
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The mitochondrial K(ATP) channel--fact or fiction? J Mol Cell Cardiol 2012; 52:578-83. [PMID: 22240339 DOI: 10.1016/j.yjmcc.2011.12.011] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/13/2011] [Revised: 12/21/2011] [Accepted: 12/21/2011] [Indexed: 01/25/2023]
Abstract
The mitochondrial ATP-dependent K(+) channel (mitoK(ATP)) is widely considered by many to play a central role in cardioprotection by ischemic and pharmacological preconditioning and by ischemic postconditioning. Nevertheless, several laboratories have questioned the existence of mitoK(ATP). This article summarizes the evidence for and against and addresses two key questions: How strong is the evidence for the presence of a K(ATP) channel in mitochondria? Are the pharmacological agents used to modulate mitoK(ATP) activity sufficiently specific to allow the role of these channels in cardioprotection to be established?
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24
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Terzic A, Alekseev AE, Yamada S, Reyes S, Olson TM. Advances in cardiac ATP-sensitive K+ channelopathies from molecules to populations. Circ Arrhythm Electrophysiol 2011; 4:577-85. [PMID: 21846889 DOI: 10.1161/circep.110.957662] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Affiliation(s)
- Andre Terzic
- Marriott Heart Disease Research Program, Division of Cardiovascular Diseases, Department of Internal Medicine, Department of Molecular Pharmacology and Experimental Therapeutics, Department of Medical Genetics, Mayo Clinic, Rochester, MN, USA.
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25
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Andersson C, Gislason GH, Jørgensen CH, Hansen PR, Vaag A, Sørensen R, Mérie C, Olesen JB, Weeke P, Schmiegelow M, Norgaard ML, Køber L, Torp-Pedersen C. Comparable long-term mortality risk associated with individual sulfonylureas in diabetes patients with heart failure. Diabetes Res Clin Pract 2011; 94:119-25. [PMID: 21831467 DOI: 10.1016/j.diabres.2011.07.011] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2011] [Revised: 06/29/2011] [Accepted: 07/07/2011] [Indexed: 12/25/2022]
Abstract
AIMS The aim was to investigate the outcomes of individual sulfonylureas in patients with heart failure (HF). METHODS All patients hospitalized with HF for the first time in 1997-2006, alive 30 days after discharge, and who received anti-diabetic monotherapy with glimepiride (n=1097), glibenclamide (glyburide) (n=1031), glipizide (n=557), gliclazide (n=251), or tolbutamide (n=541) were identified from nationwide registers. Risk of all-cause mortality was assessed by multivariable Cox regression models. RESULTS Over the median observational time of 744 (Inter Quartile Range 268-1451) days, 2242 patients (64%) died. The analysis demonstrated similar hazard ratio (HR) for mortality for treatment with glimepiride (1.10 [95% confidence interval 0.92-1.33]), glibenclamide (1.12 [0.93-1.34]), glipizide (1.14 [0.93-1.38]), tolbutamide (1.04 [0.85-1.26]), and gliclazide (reference). Grouped according to pancreatic specificity, i.e., with tolbutamide, glipizide, and gliclazide as specific, and glibenclamide, and glimepiride as non-specific agents, no differential prognosis was found between the two groups (HR 1.04 [0.96-1.14], for non-specific, compared to pancreas specific agents). The prognosis was not dependent on prior acute myocardial infarction or ischemic heart disease (p for interactions >0.3). CONCLUSIONS In current clinical practice, it is unlikely that there are considerable differences in risk of mortality associated with individual sulfonylureas in patients with heart failure.
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Affiliation(s)
- Charlotte Andersson
- Department of Cardiology, Copenhagen University Hospital, Gentofte, Hellerup, Denmark.
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26
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Reyes S, Park S, Johnson BD, Terzic A, Olson TM. KATP channel Kir6.2 E23K variant overrepresented in human heart failure is associated with impaired exercise stress response. Hum Genet 2011; 126:779-89. [PMID: 19685080 DOI: 10.1007/s00439-009-0731-9] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2009] [Accepted: 08/05/2009] [Indexed: 12/13/2022]
Abstract
ATP-sensitive K+ (K(ATP)) channels maintain cardiac homeostasis under stress, as revealed by murine gene knockout models of the KCNJ11-encoded Kir6.2 pore. However, the translational significance of K(ATP) channels in human cardiac physiology remains largely unknown. Here, the frequency of the minor K23 allele of the common functional Kir6.2 E23K polymorphism was found overrepresented in 115 subjects with congestive heart failure compared to 2,031 community-based controls (69 vs. 56%, P < 0.001). Moreover, the KK genotype, present in 18% of heart failure patients, was associated with abnormal cardiopulmonary exercise stress testing. In spite of similar baseline heart rates at rest among genotypic subgroups (EE: 72.2 ± 2.3, EK: 75.0 ± 1.8 and KK:77.1 ± 3.0 bpm), subjects with the KK genotype had a significantly reduced heart rate increase at matched workload (EE: 32.8 ± 2.7%, EK: 28.8 ± 2.1%, KK: 21.7 ± 2.6%, P < 0.05), at 75% of maximum oxygen consumption (EE: 53.9 ± 3.9%, EK: 49.9 ± 3.1%, KK: 36.8 ± 5.3%, P < 0.05), and at peak V(O2) (EE: 82.8 ± 6.0%, EK: 80.5 ± 4.7%, KK: 59.7 ± 8.1%, P < 0.05). Molecular modeling of the tetrameric Kir6.2 pore structure revealed the E23 residue within the functionally relevant intracellular slide helix region. Substitution of the wild-type E residue with an oppositely charged, bulkier K residue would potentially result in a significant structural rearrangement and disrupted interactions with neighboring Kir6.2 subunits, providing a basis for altered high-fidelity K(ATP) channel gating, particularly in the homozygous state. Blunted heart rate response during exercise is a risk factor for mortality in patients with heart failure, establishing the clinical relevance of Kir6.2 E23K as a biomarker for impaired stress performance and underscoring the essential role of K(ATP) channels in human cardiac physiology.
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Affiliation(s)
- Santiago Reyes
- Marriott Heart Disease Research Program, Mayo Clinic, Rochester, MN 55905, USA
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27
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Zingman LV, Zhu Z, Sierra A, Stepniak E, Burnett CML, Maksymov G, Anderson ME, Coetzee WA, Hodgson-Zingman DM. Exercise-induced expression of cardiac ATP-sensitive potassium channels promotes action potential shortening and energy conservation. J Mol Cell Cardiol 2011; 51:72-81. [PMID: 21439969 DOI: 10.1016/j.yjmcc.2011.03.010] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2011] [Revised: 02/19/2011] [Accepted: 03/14/2011] [Indexed: 12/25/2022]
Abstract
Physical activity is one of the most important determinants of cardiac function. The ability of the heart to increase delivery of oxygen and metabolic fuels relies on an array of adaptive responses necessary to match bodily demand while avoiding exhaustion of cardiac resources. The ATP-sensitive potassium (K(ATP)) channel has the unique ability to adjust cardiac membrane excitability in accordance with ATP and ADP levels, and up-regulation of its expression that occurs in response to exercise could represent a critical element of this adaption. However, the mechanism by which K(ATP) channel expression changes result in a beneficial effect on cardiac excitability and function remains to be established. Here, we demonstrate that an exercise-induced rise in K(ATP) channel expression enhanced the rate and magnitude of action potential shortening in response to heart rate acceleration. This adaptation in membrane excitability promoted significant reduction in cardiac energy consumption under escalating workloads. Genetic disruption of normal K(ATP) channel pore function abolished the exercise-related changes in action potential duration adjustment and caused increased cardiac energy consumption. Thus, an expression-driven enhancement in the K(ATP) channel-dependent membrane response to alterations in cardiac workload represents a previously unrecognized mechanism for adaptation to physical activity and a potential target for cardioprotection.
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Affiliation(s)
- Leonid V Zingman
- Department of Internal Medicine, University of Iowa, Carver College of Medicine, Iowa City, IA 52242, USA.
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28
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Mital R, Zhang W, Cai M, Huttinger ZM, Goodman LA, Wheeler DG, Ziolo MT, Dwyer KM, d'Apice AJF, Zweier JL, He G, Cowan PJ, Gumina RJ. Antioxidant network expression abrogates oxidative posttranslational modifications in mice. Am J Physiol Heart Circ Physiol 2011; 300:H1960-70. [PMID: 21335461 DOI: 10.1152/ajpheart.01285.2010] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Antioxidant enzymatic pathways form a critical network that detoxifies ROS in response to myocardial stress or injury. Genetic alteration of the expression levels of individual enzymes has yielded mixed results with regard to attenuating in vivo myocardial ischemia-reperfusion injury, an extreme oxidative stress. We hypothesized that overexpression of an antioxidant network (AON) composed of SOD1, SOD3, and glutathione peroxidase (GSHPx)-1 would reduce myocardial ischemia-reperfusion injury by limiting ROS-mediated lipid peroxidation and oxidative posttranslational modification (OPTM) of proteins. Both ex vivo and in vivo myocardial ischemia models were used to evaluate the effect of AON expression. After ischemia-reperfusion injury, infarct size was significantly reduced both ex vivo and in vivo, ROS formation, measured by dihydroethidium staining, was markedly decreased, ROS-mediated lipid peroxidation, measured by malondialdehyde production, was significantly limited, and OPTM of total myocardial proteins, including fatty acid-binding protein and sarco(endo)plasmic reticulum Ca(²+)-ATPase (SERCA)2a, was markedly reduced in AON mice, which overexpress SOD1, SOD3, and GSHPx-1, compared with wild-type mice. These data demonstrate that concomitant SOD1, SOD3, and GSHPX-1 expression confers marked protection against myocardial ischemia-reperfusion injury, reducing ROS, ROS-mediated lipid peroxidation, and OPTM of critical cardiac proteins, including cardiac fatty acid-binding protein and SERCA2a.
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Affiliation(s)
- R Mital
- Division of Cardiovascular Medicine, The Ohio State University, Columbus, Ohio, USA
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29
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Arrell DK, Zlatkovic Lindor J, Yamada S, Terzic A. K(ATP) channel-dependent metaboproteome decoded: systems approaches to heart failure prediction, diagnosis, and therapy. Cardiovasc Res 2011; 90:258-66. [PMID: 21321057 DOI: 10.1093/cvr/cvr046] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Systems biology provides an integrative platform by which to account for the biological complexity related to cardiac health and disease. In this way, consequences of ATP-sensitive K(+) (K(ATP)) channel deficiency for heart failure prediction, diagnosis, and therapy were resolved recently at a proteomic level. Under stress-free conditions, knockout of the Kir6.2 K(ATP) channel pore induced metabolic proteome remodelling, revealing overrepresentation of markers of cardiovascular disease. Imposed stress precipitated structural and functional defects in Kir6.2-knockout hearts, decreasing survival and validating prediction of disease susceptibility. In the setting of hypertension, a leading risk for heart failure development, proteomic analysis diagnosed the metabolism-centric impact of K(ATP) channel deficiency in disease. Bioinformatic interrogation of K(ATP) channel-dependent proteome prioritized heart-specific adverse effects, exposing cardiomyopathic traits of aggravated contractility, fibrosis, and ventricular hypertrophy. In dilated cardiomyopathy induced by Kir6.2-knockout pressure overload, proteomic remodelling was exacerbated, underlying a multifaceted molecular pathology that indicates the necessity for a broad-based strategy to achieve repair. Embryonic stem cell intervention in cardiomyopathic K(ATP) channel knockout hearts elicited a distinct proteome signature that forecast amelioration of adverse cardiac outcomes. Functional/structural measurements validated improved contractile performance, reduced ventricular size, and decreased cardiac damage in the treated cohort, while systems assessment unmasked cardiovascular development as a prioritized biological function in stem cell-reconstructed hearts. Thus, proteomic deconvolution of K(ATP) channel-deficient hearts provides definitive evidence for the channel's homeostatic contribution to the cardiac metaboproteome and establishes the utility of systems-oriented approaches to predict disease susceptibility, diagnose consequences of heart failure progression, and monitor therapy outcome.
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Affiliation(s)
- D Kent Arrell
- Marriott Heart Disease Research Program, Mayo Clinic, Stabile 5, 200 First Street SW, Rochester, MN, USA
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30
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Reyes S, Kane GC, Zingman LV, Yamada S, Terzic A. Targeted disruption of K(ATP) channels aggravates cardiac toxicity in cocaine abuse. Clin Transl Sci 2010; 2:361-5. [PMID: 20443920 DOI: 10.1111/j.1752-8062.2009.00145.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Cocaine is the most frequently used illicit drug among individuals seeking emergency-room care, with fatal outcome most often attributable to the cardiovascular manifestations of drug abuse. While the symptomatic presentations of cocaine toxicity are increasingly understood, the molecular determinants that define outcome remain largely unknown. Here, we report that the susceptibility to cocaine-induced cardiotoxicity is genetically regulated. Targeted deletion of the KCNJ11-encoded Kir6.2 pore-forming subunit of sarcolemmal K(ATP) channels resulted in amplified vulnerability to the toxic effects of chronic cocaine abuse. Under the hyperadrenergic stress, imposed by daily 3-week-long intraperitoneal administration of 30 mg/kg cocaine in Kir6.2-knockout mice, failure to maintain cardiac homeostasis translated into decreased exercise tolerance revealed by poor treadmill stress performance, and dilated hypokinetic left hearts with aggravated cellular hypertrophy and pathognomonic characteristics of chronic cocaine-induced cardiac toxicity. This study therefore reveals a previously unrecognized role of Kir6.2-encoded K(ATP) channels in determining cardiovascular outcome in chronic cocaine abuse, identifying a novel molecular determinant of cocaine cardiotoxicity.
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Affiliation(s)
- Santiago Reyes
- Department of Medicine, Mayo Clinic, Rochester, Minnesota, USA
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31
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Reyes S, Park S, Terzic A, Alekseev AE. K(ATP) channels process nucleotide signals in muscle thermogenic response. Crit Rev Biochem Mol Biol 2010; 45:506-19. [PMID: 20925594 DOI: 10.3109/10409238.2010.513374] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Uniquely gated by intracellular adenine nucleotides, sarcolemmal ATP-sensitive K(+) (K(ATP)) channels have been typically assigned to protective cellular responses under severe energy insults. More recently, K(ATP) channels have been instituted in the continuous control of muscle energy expenditure under non-stressed, physiological states. These advances raised the question of how K(ATP) channels can process trends in cellular energetics within a milieu where each metabolic system is set to buffer nucleotide pools. Unveiling the mechanistic basis of the K(ATP) channel-driven thermogenic response in muscles thus invites the concepts of intracellular compartmentalization of energy and proteins, along with nucleotide signaling over diffusion barriers. Furthermore, it requires gaining insight into the properties of reversibility of intrinsic ATPase activity associated with K(ATP) channel complexes. Notwithstanding the operational paradigm, the homeostatic role of sarcolemmal K(ATP) channels can be now broadened to a wider range of environmental cues affecting metabolic well-being. In this way, under conditions of energy deficit such as ischemic insult or adrenergic stress, the operation of K(ATP) channel complexes would result in protective energy saving, safeguarding muscle performance and integrity. Under energy surplus, downregulation of K(ATP) channel function may find potential implications in conditions of energy imbalance linked to obesity, cold intolerance and associated metabolic disorders.
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Affiliation(s)
- Santiago Reyes
- Marriott Heart Diseases Research Program, Division of Cardiovascular Diseases, Department of Medicine, Mayo Clinic, Rochester, Minnesota 55905, USA
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32
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Stoller DA, Fahrenbach JP, Chalupsky K, Tan BH, Aggarwal N, Metcalfe J, Hadhazy M, Shi NQ, Makielski JC, McNally EM. Cardiomyocyte sulfonylurea receptor 2-KATP channel mediates cardioprotection and ST segment elevation. Am J Physiol Heart Circ Physiol 2010; 299:H1100-8. [PMID: 20656890 DOI: 10.1152/ajpheart.00084.2010] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Sulfonylurea receptor-containing ATP-sensitive potassium (K(ATP)) channels have been implicated in cardioprotection, but the cell type and constitution of channels responsible for this protection have not been clear. Mice deleted for the first nucleotide binding region of sulfonylurea receptor 2 (SUR2) are referred to as SUR2 null since they lack full-length SUR2 and glibenclamide-responsive K(ATP) channels in cardiac, skeletal, and smooth muscle. As previously reported, SUR2 null mice develop electrocardiographic changes of ST segment elevation that were shown to correlate with coronary artery vasospasm. Here we restored expression of the cardiomyocyte SUR2-K(ATP) channel in SUR2 null mice by generating transgenic mice with ventricular cardiomyocyte-restricted expression of SUR2A. Introduction of the cardiomyocyte SUR2A transgene into the SUR2 null background restored functional cardiac K(ATP) channels. Hearts isolated from rescued mice, referred to as MLC2A, had significantly reduced infarct size (27 ± 3% of area at risk) compared with SUR2 null mice (36 ± 3% of area at risk). Compared with SUR2 null hearts, MLC2A hearts exhibited significantly improved cardiac function during the postischemia reperfusion period primarily because of preservation of low diastolic pressures. Additionally, restoration of cardiac SUR2-K(ATP) channels significantly reduced the degree and frequency of ST segment elevation episodes in MLC2A mice. Therefore, cardioprotective mechanisms both dependent and independent of SUR2-K(ATP) channels contribute to cardiac function.
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Affiliation(s)
- Douglas A Stoller
- Committee on Cellular and Molecular Physiology, University of Chicago, Chicago, IL 60637, USA
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33
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Abstract
Despite a high prevalence of sudden cardiac death throughout the world, the mechanisms that lead to ventricular arrhythmias are not fully understood. Over the last 20 years, a growing body of evidence indicates that cardiac mitochondria are involved in the genesis of arrhythmia. In this review, we have attempted to describe the role that mitochondria play in altering the heart's electrical function by introducing heterogeneity into the cardiac action potential. Specifically, we have focused on how the energetic status of the mitochondrial network can alter sarcolemmal potassium fluxes through ATP-sensitive potassium channels, creating a 'metabolic sink' for depolarizing wave-fronts and introducing conditions that favour catastrophic arrhythmia. Mechanisms by which mitochondria depolarize under conditions of oxidative stress are characterized, and the contributions of several mitochondrial ion channels to mitochondrial depolarization are presented. The inner membrane anion channel in particular opens upstream of other inner membrane channels during metabolic stress, and may be an effective target to prevent the metabolic oscillations that create action potential lability. Finally, we discuss therapeutic strategies that prevent arrhythmias by preserving mitochondrial membrane potential in the face of oxidative stress, supporting the notion that treatments aimed at cardiac mitochondria have significant potential in attenuating electrical dysfunction in the heart.
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Affiliation(s)
- David A Brown
- Department of Physiology, Brody School of Medicine and the East Carolina Heart Institute, East Carolina University, Room 6N-98, 600 Moye Blvd, Greenville, NC 27834, USA.
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Arrell DK, Zlatkovic J, Kane GC, Yamada S, Terzic A. ATP-sensitive K+ channel knockout induces cardiac proteome remodeling predictive of heart disease susceptibility. J Proteome Res 2010; 8:4823-34. [PMID: 19673485 DOI: 10.1021/pr900561g] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Forecasting disease susceptibility requires detection of maladaptive signatures prior to onset of overt symptoms. A case-in-point are cardiac ATP-sensitive K+ (K(ATP)) channelopathies, for which the substrate underlying disease vulnerability remains to be identified. Resolving molecular pathobiology, even for single genetic defects, mandates a systems platform to reliably diagnose disease predisposition. High-throughput proteomic analysis was here integrated with network biology to decode consequences of Kir6.2 K(ATP) channel pore deletion. Differential two-dimensional gel electrophoresis reproducibly resolved >800 protein species from hearts of asymptomatic wild-type and Kir6.2-knockout counterparts. K(ATP) channel ablation remodeled the cardiac proteome, significantly altering 71 protein spots, from which 102 unique identities were assigned following hybrid linear ion trap quadrupole-Orbitrap tandem mass spectrometry. Ontological annotation stratified the K(ATP) channel-dependent protein cohort into a predominant bioenergetic module (63 resolved identities), with additional focused sets representing signaling molecules (6), oxidoreductases (8), chaperones (6), and proteins involved in catabolism (6), cytostructure (8), and transcription and translation (5). Protein interaction mapping, in conjunction with expression level changes, localized a K(ATP) channel-associated subproteome within a nonstochastic scale-free network. Global assessment of the K(ATP) channel deficient environment verified the primary impact on metabolic pathways and revealed overrepresentation of markers associated with cardiovascular disease. Experimental imposition of graded stress precipitated exaggerated structural and functional myocardial defects in the Kir6.2-knockout, decreasing survivorship and validating the forecast of disease susceptibility. Proteomic cartography thus provides an integral view of molecular remodeling in the heart induced by K(ATP) channel deletion, establishing a systems approach that predicts outcome at a presymptomatic stage.
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Affiliation(s)
- D Kent Arrell
- Marriott Heart Disease Research Program, Division of Cardiovascular Diseases, Department of Medicine, Mayo Clinic, Rochester, Minnesota 55905, USA
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Human K(ATP) channelopathies: diseases of metabolic homeostasis. Pflugers Arch 2009; 460:295-306. [PMID: 20033705 PMCID: PMC2883927 DOI: 10.1007/s00424-009-0771-y] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2009] [Accepted: 11/30/2009] [Indexed: 10/27/2022]
Abstract
Assembly of an inward rectifier K+ channel pore (Kir6.1/Kir6.2) and an adenosine triphosphate (ATP)-binding regulatory subunit (SUR1/SUR2A/SUR2B) forms ATP-sensitive K+ (KATP) channel heteromultimers, widely distributed in metabolically active tissues throughout the body. KATP channels are metabolism-gated biosensors functioning as molecular rheostats that adjust membrane potential-dependent functions to match cellular energetic demands. Vital in the adaptive response to (patho)physiological stress, KATP channels serve a homeostatic role ranging from glucose regulation to cardioprotection. Accordingly, genetic variation in KATP channel subunits has been linked to the etiology of life-threatening human diseases. In particular, pathogenic mutations in KATP channels have been identified in insulin secretion disorders, namely, congenital hyperinsulinism and neonatal diabetes. Moreover, KATP channel defects underlie the triad of developmental delay, epilepsy, and neonatal diabetes (DEND syndrome). KATP channelopathies implicated in patients with mechanical and/or electrical heart disease include dilated cardiomyopathy (with ventricular arrhythmia; CMD1O) and adrenergic atrial fibrillation. A common Kir6.2 E23K polymorphism has been associated with late-onset diabetes and as a risk factor for maladaptive cardiac remodeling in the community-at-large and abnormal cardiopulmonary exercise stress performance in patients with heart failure. The overall mutation frequency within KATP channel genes and the spectrum of genotype-phenotype relationships remain to be established, while predicting consequences of a deficit in channel function is becoming increasingly feasible through systems biology approaches. Thus, advances in molecular medicine in the emerging field of human KATP channelopathies offer new opportunities for targeted individualized screening, early diagnosis, and tailored therapy.
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Lefer DJ, Nichols CG, Coetzee WA. Sulfonylurea receptor 1 subunits of ATP-sensitive potassium channels and myocardial ischemia/reperfusion injury. Trends Cardiovasc Med 2009; 19:61-7. [PMID: 19577714 DOI: 10.1016/j.tcm.2009.04.008] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
K(ATP) channels are generally cardioprotective under conditions of metabolic impairment, consisting of pore-forming (Kir6.1 and/or Kir6.2) and sulphonylurea-binding, modulatory subunits [sulfonylurea receptor (SUR) 1, 2A, or 2B]. Cardiovascular K(ATP) channels are generally thought to consist of Kir6.2/SUR2A subunits (in the case of heart muscle) or Kir6.1/SUR2B subunits (smooth muscle), whereas SUR1-containing channels have well-documented roles in pancreatic insulin release. Recent data, however, demonstrated the presence of SUR1 subunits in mouse cardiac tissue (particularly in atria) and a surprising protection from myocardial ischemia/reperfusion in SUR1-null mice. Here, we review some of the extra-pancreatic roles assigned to SUR1 subunits and consider whether these might be involved in the sequelae of ischemia/reperfusion.
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Affiliation(s)
- David J Lefer
- Department of Surgery, Division of Cardiothoracic Surgery, Emory University School of Medicine, Atlanta, GA, USA
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37
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Zlatkovic J, Arrell DK, Kane GC, Miki T, Seino S, Terzic A. Proteomic profiling of KATP channel-deficient hypertensive heart maps risk for maladaptive cardiomyopathic outcome. Proteomics 2009; 9:1314-25. [PMID: 19253285 DOI: 10.1002/pmic.200800718] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
KCNJ11 null mutants, lacking Kir6.2 ATP-sensitive K(+) (K(ATP)) channels, exhibit a marked susceptibility towards hypertension (HTN)-induced heart failure. To gain insight into the molecular alterations induced by knockout of this metabolic sensor under hemodynamic stress, wild-type (WT) and Kir6.2 knockout (Kir6.2-KO) cardiac proteomes were profiled by comparative 2-DE and Orbitrap MS. Despite equivalent systemic HTN produced by chronic hyperaldosteronism, 114 unique proteins were altered in Kir6.2-KO compared to WT hearts. Bioinformatic analysis linked the primary biological function of the K(ATP) channel-dependent protein cohort to energetic metabolism (64% of proteins), followed by signaling infrastructure (36%) including oxidoreductases, stress-related chaperones, processes supporting protein degradation, transcription and translation, and cytostructure. Mapped protein-protein relationships authenticated the primary impact on metabolic pathways, delineating the K(ATP) channel-dependent subproteome within a nonstochastic network. Iterative systems interrogation of the proteomic web prioritized heart-specific adverse effects, i.e., "Cardiac Damage", "Cardiac Enlargement", and "Cardiac Fibrosis", exposing a predisposition for the development of cardiomyopathic traits in the hypertensive Kir6.2-KO. Validating this maladaptive forecast, phenotyping documented an aggravated myocardial contractile performance, a massive interstitial fibrosis and an exaggerated left ventricular size, all prognostic indices of poor outcome. Thus, Kir6.2 ablation engenders unfavorable proteomic remodeling in hypertensive hearts, providing a composite molecular substrate for pathologic stress-associated cardiovascular disease.
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Affiliation(s)
- Jelena Zlatkovic
- Division of Cardiovascular Diseases, Department of Medicine, Mayo Clinic, Rochester, MN 55905, USA
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Nelson TJ, Martinez-Fernandez A, Terzic A. KCNJ11 knockout morula re-engineered by stem cell diploid aggregation. Philos Trans R Soc Lond B Biol Sci 2009; 364:269-76. [PMID: 18977736 DOI: 10.1098/rstb.2008.0179] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
KCNJ11-encoded Kir6.2 assembles with ATP-binding cassette sulphonylurea receptors to generate ATP-sensitive K+ (KATP) channel complexes. Expressed in tissues with dynamic metabolic flux, these evolutionarily conserved yet structurally and functionally unique heteromultimers serve as high-fidelity rheostats that adjust membrane potential-dependent cell functions to match energetic demand. Genetic defects in channel subunits disrupt the cellular homeostatic response to environmental stress, compromising organ tolerance in the adult. As maladaptation characterizes malignant KATP channelopathies, establishment of platforms to examine progression of KATP channel-dependent adaptive behaviour is warranted. Chimeras provide a powerful tool to assay the contribution of genetic variance to stress intolerance during prenatal or post-natal development. Here, KCNJ11 KATP channel gene knockout<-->wild-type chimeras were engineered through diploid aggregation. Integration of wild-type embryonic stem cells into zona pellucida-denuded morula derived from knockout embryos achieved varying degrees of incorporation of stress-tolerant tissue within the KATP channel-deficient background. Despite the stress-vulnerable phenotype of the knockout, ex vivo derived mosaic blastocysts tolerated intrauterine transfer and implantation, followed by full-term embryonic development in pseudopregnant surrogates to produce live chimeric offspring. The development of adult chimerism from the knockout<-->wild-type mosaic embryo offers thereby a new paradigm to probe the ecogenetic control of the KATP channel-dependent stress response.
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Affiliation(s)
- Timothy J Nelson
- Departments of Medicine, Marriott Heart Disease Research Program, Division of Cardiovascular Diseases, Mayo Clinic, Rochester, MN 55905, USA
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Hu X, Xu X, Huang Y, Fassett J, Flagg TP, Zhang Y, Nichols CG, Bache RJ, Chen Y. Disruption of sarcolemmal ATP-sensitive potassium channel activity impairs the cardiac response to systolic overload. Circ Res 2008; 103:1009-17. [PMID: 18802029 DOI: 10.1161/circresaha.107.170795] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Sarcolemmal ATP-sensitive potassium channels (K(ATP)) act as metabolic sensors that facilitate adaptation of the left ventricle to changes in energy requirements. This study examined the mechanism by which K(ATP) dysfunction impairs the left ventricular response to stress using transgenic mouse strains with cardiac-specific disruption of K(ATP) activity (SUR1-tg mice) or Kir6.2 gene deficiency (Kir6.2 KO). Both SUR1-tg and Kir6.2 KO mice had normal left ventricular mass and function under unstressed conditions. Following chronic transverse aortic constriction, both SUR1-tg and Kir6.2 KO mice developed more severe left ventricular hypertrophy and dysfunction as compared with their corresponding WT controls. Both SUR1-tg and Kir6.2 KO mice had significantly decreased expression of peroxisome proliferator-activated receptor gamma coactivator (PGC)-1alpha and a group of energy metabolism related genes at both protein and mRNA levels. Furthermore, disruption of K(ATP) repressed expression and promoter activity of PGC-1alpha in cultured rat neonatal cardiac myocytes in response to hypoxia, indicating that K(ATP) activity is required to maintain PGC-1alpha expression under stress conditions. PGC-1alpha gene deficiency also exacerbated chronic transverse aortic constriction-induced ventricular hypertrophy and dysfunction, suggesting that depletion of PGC-1alpha can worsen systolic overload induced ventricular dysfunction. Both SUR1-tg and Kir6.2 KO mice had decreased FOXO1 after transverse aortic constriction, in agreement with the reports that a decrease of FOXO1 can repress PGC-1alpha expression. Furthermore, inhibition of K(ATP) caused a decrease of FOXO1 associated with PGC-1alpha promoter. These data indicate that K(ATP) channels facilitate the cardiac response to stress by regulating PGC-1alpha and its target genes, at least partially through the FOXO1 pathway.
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Affiliation(s)
- Xinli Hu
- Cardiovascular Division, Department of Medicine, Universityof Minnesota Medical School, Minneapolis, MN 55455, USA
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40
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Stoller D, Kakkar R, Smelley M, Chalupsky K, Earley JU, Shi NQ, Makielski JC, McNally EM. Mice lacking sulfonylurea receptor 2 (SUR2) ATP-sensitive potassium channels are resistant to acute cardiovascular stress. J Mol Cell Cardiol 2007; 43:445-54. [PMID: 17765261 PMCID: PMC2745323 DOI: 10.1016/j.yjmcc.2007.07.058] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/25/2007] [Revised: 07/16/2007] [Accepted: 07/19/2007] [Indexed: 11/24/2022]
Abstract
Adenosine triphosphate-sensitive potassium (K(ATP)) channels are thought to mediate the stress response by sensing intracellular ATP concentration. Cardiomyocyte K(ATP) channels are composed of the pore-forming Kir6.2 subunit and the regulatory sulfonylurea receptor 2 (SUR2). We studied the response to acute isoproterenol in SUR2 null mice as a model of acute adrenergic stress and found that the episodic coronary vasospasm observed at baseline in SUR2 null mice was alleviated. Similar results were observed following administration of a nitric oxide donor consistent with a vasodilatory role. Langendorff-perfused hearts were subjected to global ischemia, and hearts from SUR2 null mice exhibited significantly reduced infarct size (54+/-4 versus 30+/-3%) and improved cardiac function compared to control mice. SUR2 null mice have hypertension and develop cardiac hypertrophy. However, despite longstanding hypertension, fibrosis was absent in SUR2 null mice. SUR2 null mice were administered nifedipine to block baseline coronary vasospasm, and hearts from nifedipine-treated SUR2 null mice exhibited increased infarct size compared to untreated SUR2 null mice (42+/-3% versus 54+/-3%). We conclude that conventional sarcolemmal cardiomyocyte K(ATP) channels containing full-length SUR2 are not required for mediating the response to acute cardiovascular stress.
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Affiliation(s)
- Douglas Stoller
- Committee on Cell Physiology, The University of Chicago, Chicago, IL 60637, USA
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41
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Halestrap AP, Clarke SJ, Khaliulin I. The role of mitochondria in protection of the heart by preconditioning. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2007; 1767:1007-31. [PMID: 17631856 PMCID: PMC2212780 DOI: 10.1016/j.bbabio.2007.05.008] [Citation(s) in RCA: 299] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Figures] [Subscribe] [Scholar Register] [Received: 04/23/2007] [Revised: 05/18/2007] [Accepted: 05/23/2007] [Indexed: 12/16/2022]
Abstract
A prolonged period of ischaemia followed by reperfusion irreversibly damages the heart. Such reperfusion injury (RI) involves opening of the mitochondrial permeability transition pore (MPTP) under the conditions of calcium overload and oxidative stress that accompany reperfusion. Protection from MPTP opening and hence RI can be mediated by ischaemic preconditioning (IP) where the prolonged ischaemic period is preceded by one or more brief (2–5 min) cycles of ischaemia and reperfusion. Following a brief overview of the molecular characterisation and regulation of the MPTP, the proposed mechanisms by which IP reduces pore opening are reviewed including the potential roles for reactive oxygen species (ROS), protein kinase cascades, and mitochondrial potassium channels. It is proposed that IP-mediated inhibition of MPTP opening at reperfusion does not involve direct phosphorylation of mitochondrial proteins, but rather reflects diminished oxidative stress during prolonged ischaemia and reperfusion. This causes less oxidation of critical thiol groups on the MPTP that are known to sensitise pore opening to calcium. The mechanisms by which ROS levels are decreased in the IP hearts during prolonged ischaemia and reperfusion are not known, but appear to require activation of protein kinase Cε, either by receptor-mediated events or through transient increases in ROS during the IP protocol. Other signalling pathways may show cross-talk with this primary mechanism, but we suggest that a role for mitochondrial potassium channels is unlikely. The evidence for their activity in isolated mitochondria and cardiac myocytes is reviewed and the lack of specificity of the pharmacological agents used to implicate them in IP is noted. Some K+ channel openers uncouple mitochondria and others inhibit respiratory chain complexes, and their ability to produce ROS and precondition hearts is mimicked by bona fide uncouplers and respiratory chain inhibitors. IP may also provide continuing protection during reperfusion by preventing a cascade of MPTP-induced ROS production followed by further MPTP opening. This phase of protection may involve survival kinase pathways such as Akt and glycogen synthase kinase 3 (GSK3) either increasing ROS removal or reducing mitochondrial ROS production.
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Affiliation(s)
- Andrew P Halestrap
- Department of Biochemistry and Bristol Heart Institute, University of Bristol, School of Medical Sciences, University Walk, Bristol BS8 1TD, UK.
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42
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Hilgemann DW. On the physiological roles of PIP(2) at cardiac Na+ Ca2+ exchangers and K(ATP) channels: a long journey from membrane biophysics into cell biology. J Physiol 2007; 582:903-9. [PMID: 17463041 PMCID: PMC2075268 DOI: 10.1113/jphysiol.2007.132746] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Over the last 10 years we have tried to understand the roles of PIP(2) in regulating cardiac Na(+)-Ca(2+) exchangers and K(ATP) K(+) channels, both of which are directly activated by PIP(2). Up to now, the idea that hormones might physiologically regulate these mechanisms by causing changes of PIP(2) concentrations in the cardiac sarcolemma, either locally or globally, is not well supported. In intact myocardium, but not excised patches, phosphatidylinositol 4-phosphate 5-kinase (PIP5K) activity appears to be Ca(2+) activated and dependent on cardiac activity. Potentially therefore the primary second messenger of the heart, cytoplasmic Ca(2+), may regulate PIP(2) and therewith numerous cardiac membrane processes. In general, however, PIP(2) may simply serve to strongly activate various cardiac channels and transporters when they are inserted in the sarcolemma, while a lack of PIP(2) on internal membranes maintains transporters and channels inactive during trafficking and processing. As in most, if not all, strong regulatory systems of cells, the activating effects of PIP(2) can apparently be countered by strong inactivation mechanisms. In this context, our recent work suggests that internalization of cardiac Na(+)-Ca(2+) exchangers is promoted by increased PIP(2) synthesis, especially in combination with other cell signals. Assuming that multiple adapter-PIP(2) interactions are necessary to initiate the budding of individual membrane vesicles, the dependence of endocytosis on PIP(2) in the surface membrane can potentially be a very steep function. Thus, a better understanding of the regulation of cardiac lipid kinases may be key to understanding when and how cardiac ion transporters and channels are internalized.
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Affiliation(s)
- Donald W Hilgemann
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9040, USA.
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