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Szabo BC, Szabo M, Nagy P, Varga Z, Panyi G, Kovacs T, Zakany F. Novel insights into the modulation of the voltage-gated potassium channel K V1.3 activation gating by membrane ceramides. J Lipid Res 2024:100596. [PMID: 39019344 DOI: 10.1016/j.jlr.2024.100596] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2024] [Revised: 07/08/2024] [Accepted: 07/10/2024] [Indexed: 07/19/2024] Open
Abstract
Membrane lipids extensively modulate the activation gating of voltage-gated potassium channels (KV), however, much less is known about mechanisms of ceramide and glucosylceramide actions including which structural element is the main intramolecular target and whether there is any contribution of indirect, membrane biophysics-related mechanisms to their actions. We used two-electrode voltage-clamp fluorometry capable of recording currents and fluorescence signals to simultaneously monitor movements of the pore domain (PD) and the voltage sensor domain (VSD) of the KV1.3 ion channel after attaching an MTS-TAMRA fluorophore to a cysteine introduced into the extracellular S3-S4 loop of the VSD. We observed rightward shifts in the conductance-voltage (G-V) relationship, slower current activation kinetics and reduced current amplitudes in response to loading the membrane with C16-ceramide (Cer) or C16-glucosylceramide (GlcCer). When analyzing VSD movements, only Cer induced a rightward shift in the fluorescence signal-voltage (F-V) relationship and slowed fluorescence activation kinetics, whereas GlcCer exerted no such effects. These results point at a distinctive mechanism of action with Cer primarily targeting the VSD, while GlcCer only the PD of KV1.3. Using environment-sensitive probes and fluorescence-based approaches, we show that Cer and GlcCer similarly increase molecular order in the inner, hydrophobic regions of bilayers, however, Cer induces a robust molecular reorganization at the membrane-water interface. We propose that this unique ordering effect in the outermost membrane layer in which the main VSD rearrangement involving an outward sliding of the top of S4 occurs, can explain the VSD targeting mechanism of Cer, which is unavailable for GlcCer.
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Affiliation(s)
- Bence Cs Szabo
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Egyetem square 1, H-4032 Debrecen, Hungary
| | - Mate Szabo
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Egyetem square 1, H-4032 Debrecen, Hungary
| | - Peter Nagy
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Egyetem square 1, H-4032 Debrecen, Hungary
| | - Zoltan Varga
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Egyetem square 1, H-4032 Debrecen, Hungary
| | - Gyorgy Panyi
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Egyetem square 1, H-4032 Debrecen, Hungary
| | - Tamas Kovacs
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Egyetem square 1, H-4032 Debrecen, Hungary.
| | - Florina Zakany
- Department of Biophysics and Cell Biology, Faculty of Medicine, University of Debrecen, Egyetem square 1, H-4032 Debrecen, Hungary.
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Quiroz-Acosta T, Bermeo K, Arenas I, Garcia DE. Inactivation of potassium channels by ceramide in rat pancreatic β-cells. Arch Biochem Biophys 2023; 735:109520. [PMID: 36646267 DOI: 10.1016/j.abb.2023.109520] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Revised: 12/29/2022] [Accepted: 01/12/2023] [Indexed: 01/15/2023]
Abstract
Lipid regulation of ion channels is a fundamental mechanism in physiological processes as of neurotransmitter release and hormone secretion. Ceramide is a bioactive lipid proposed as a regulator of several voltage-gated ion channels including potassium channels (Kv). It is generated either de novo or by sphingomyelin (SM) hydrolysis in membranes of mammalian cells. In pancreatic β-cells, ceramide is the main sphingolipid associated with lipotoxicity and likely involved in cell dysfunction. Despite of the wealth of information regarding regulation of potassium channels by ceramides, the regulation of Kv channels by accumulated ceramide in native pancreatic β-cells has not been investigated. To do so, we used either the C2-ceramide, a cell-permeable short-chain analogue, or a sphingomyelinase (SMase C), a hydrolase causing ceramide to elevate from an endogenous production, in pancreatic β-cells of rat. C2-ceramide markedly accelerates steady-state current inactivation according to kinetic changes in the channel machinery. Interestingly, only C2-ceramide accelerates current inactivation while SMase C decreases both, peak-current and step-current amplitude supporting differential effects of ceramide derivatives. A specific inhibitor of the Kv2.1 channel (GxTX-1E), readily inhibits a fraction of the Kv channel current while no further inhibition by C2-ceramide superfusion can be observed supporting Kv2.1 channel involvement in the ceramide inhibition. Thus, intramembrane ceramide accumulation, as a lipidic metabolite released under cell-stress conditions, may alter pancreatic β-cell repolarization and secretion. These results may provide a new insight regarding lipid-protein regulation and advance our understanding in ceramide actions on Kv channels in pancreatic β-cells.
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Affiliation(s)
- Tayde Quiroz-Acosta
- Department of Physiology, Faculty of Medicine, Universidad Nacional Autónoma de México, UNAM, Circuito Exterior S/N, Ciudad Universitaria, Coyoacán, 04510, Ciudad de México, México
| | - Karina Bermeo
- Department of Physiology, Faculty of Medicine, Universidad Nacional Autónoma de México, UNAM, Circuito Exterior S/N, Ciudad Universitaria, Coyoacán, 04510, Ciudad de México, México
| | - Isabel Arenas
- Department of Physiology, Faculty of Medicine, Universidad Nacional Autónoma de México, UNAM, Circuito Exterior S/N, Ciudad Universitaria, Coyoacán, 04510, Ciudad de México, México
| | - David E Garcia
- Department of Physiology, Faculty of Medicine, Universidad Nacional Autónoma de México, UNAM, Circuito Exterior S/N, Ciudad Universitaria, Coyoacán, 04510, Ciudad de México, México.
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Borodzicz-Jażdżyk S, Jażdżyk P, Łysik W, Cudnoch-Jȩdrzejewska A, Czarzasta K. Sphingolipid metabolism and signaling in cardiovascular diseases. Front Cardiovasc Med 2022; 9:915961. [PMID: 36119733 PMCID: PMC9471951 DOI: 10.3389/fcvm.2022.915961] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Accepted: 08/05/2022] [Indexed: 01/10/2023] Open
Abstract
Sphingolipids are a structural component of the cell membrane, derived from sphingosine, an amino alcohol. Its sphingoid base undergoes various types of enzymatic transformations that lead to the formation of biologically active compounds, which play a crucial role in the essential pathways of cellular signaling, proliferation, maturation, and death. The constantly growing number of experimental and clinical studies emphasizes the pivotal role of sphingolipids in the pathophysiology of cardiovascular diseases, including, in particular, ischemic heart disease, hypertension, heart failure, and stroke. It has also been proven that altering the sphingolipid metabolism has cardioprotective properties in cardiac pathologies, including myocardial infarction. Recent studies suggest that selected sphingolipids may serve as valuable biomarkers useful in the prognosis of cardiovascular disorders in clinical practice. This review aims to provide an overview of the current knowledge of sphingolipid metabolism and signaling in cardiovascular diseases.
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Affiliation(s)
- Sonia Borodzicz-Jażdżyk
- Chair and Department of Experimental and Clinical Physiology, Laboratory of Centre for Preclinical Research, Medical University of Warsaw, Warsaw, Poland
| | - Piotr Jażdżyk
- Chair and Department of Experimental and Clinical Physiology, Laboratory of Centre for Preclinical Research, Medical University of Warsaw, Warsaw, Poland
- Second Department of Psychiatry, Institute of Psychiatry and Neurology in Warsaw, Warsaw, Poland
| | - Wojciech Łysik
- Chair and Department of Experimental and Clinical Physiology, Laboratory of Centre for Preclinical Research, Medical University of Warsaw, Warsaw, Poland
| | - Agnieszka Cudnoch-Jȩdrzejewska
- Chair and Department of Experimental and Clinical Physiology, Laboratory of Centre for Preclinical Research, Medical University of Warsaw, Warsaw, Poland
| | - Katarzyna Czarzasta
- Chair and Department of Experimental and Clinical Physiology, Laboratory of Centre for Preclinical Research, Medical University of Warsaw, Warsaw, Poland
- *Correspondence: Katarzyna Czarzasta,
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Abstract
PURPOSE OF REVIEW Total ceramide levels in cardiac tissue relate to cardiac dysfunction in animal models. However, emerging evidence suggests that the fatty acyl chain length of ceramides also impacts their relationship to cardiac function. This review explores evidence regarding the relationship between ceramides and left ventricular dysfunction and heart failure. It further explores possible mechanisms underlying these relationships. RECENT FINDINGS In large, community-based cohorts, a higher ratio of specific plasma ceramides, C16 : 0/C24 : 0, related to worse left ventricular dysfunction. Increased left ventricular mass correlated with plasma C16 : 0/C24 : 0, but this relationship became nonsignificant after adjustment for multiple comparisons. Decreased left atrial function and increased left atrial size also related to C16 : 0/C24 : 0. Furthermore, increased incident heart failure, overall cardiovascular disease (CVD) mortality and all-cause mortality were associated with higher C16 : 0/C24 : 0 (or lower C24 : 0/C16 : 0). Finally, a number of possible biological mechanisms are outlined supporting the link between C16 : 0/C24 : 0 ceramides, ceramide signalling and CVD. SUMMARY High cardiac levels of total ceramides are noted in heart failure. In the plasma, C16 : 0/C24 : 0 ceramides may be a valuable biomarker of preclinical left ventricular dysfunction, remodelling, heart failure and mortality. Continued exploration of the mechanisms underlying these profound relationships may help develop specific lipid modulators to combat cardiac dysfunction and heart failure.
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Affiliation(s)
- Lauren K. Park
- Department of Medicine, Division of Cardiology, Washington University School of Medicine, Saint Louis, Missouri
| | - Valene Garr-Barry
- Department of Medicine, Division of Cardiology, Washington University School of Medicine, Saint Louis, Missouri
| | - Juan Hong
- Department of Medicine, Division of Cardiology, Washington University School of Medicine, Saint Louis, Missouri
| | - John Heebink
- Department of Medicine, Division of Cardiology, Washington University School of Medicine, Saint Louis, Missouri
| | - Rajan Sah
- Department of Medicine, Division of Cardiology, Washington University School of Medicine, Saint Louis, Missouri
| | - Linda R. Peterson
- Department of Medicine, Division of Cardiology, Washington University School of Medicine, Saint Louis, Missouri
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Miranda WE, Guo J, Mesa-Galloso H, Corradi V, Lees-Miller JP, Tieleman DP, Duff HJ, Noskov SY. Lipid regulation of hERG1 channel function. Nat Commun 2021; 12:1409. [PMID: 33658490 PMCID: PMC7930123 DOI: 10.1038/s41467-021-21681-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Accepted: 01/29/2021] [Indexed: 01/31/2023] Open
Abstract
The lipid regulation of mammalian ion channel function has emerged as a fundamental mechanism in the control of electrical signalling and transport specificity in various cell types. In this work, we combine molecular dynamics simulations, mutagenesis, and electrophysiology to provide mechanistic insights into how lipophilic molecules (ceramide-sphingolipid probe) alter gating kinetics and K+ currents of hERG1. We show that the sphingolipid probe induced a significant left shift of activation voltage, faster deactivation rates, and current blockade comparable to traditional hERG1 blockers. Microseconds-long MD simulations followed by experimental mutagenesis elucidated ceramide specific binding locations at the interface between the pore and voltage sensing domains. This region constitutes a unique crevice present in mammalian channels with a non-swapped topology. The combined experimental and simulation data provide evidence for ceramide-induced allosteric modulation of the channel by a conformational selection mechanism.
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Affiliation(s)
- Williams E Miranda
- Centre for Molecular Simulation and Department of Biological Sciences, 507 Campus Drive, University of Calgary, Calgary, AB, Canada
| | - Jiqing Guo
- Department of Cardiac Sciences, Libin Cardiovascular Institute of Alberta, 3280 Hospital Dr., University of Calgary, Calgary, AB, Canada
| | - Haydee Mesa-Galloso
- Centre for Molecular Simulation and Department of Biological Sciences, 507 Campus Drive, University of Calgary, Calgary, AB, Canada
| | - Valentina Corradi
- Centre for Molecular Simulation and Department of Biological Sciences, 507 Campus Drive, University of Calgary, Calgary, AB, Canada
| | - James P Lees-Miller
- Department of Cardiac Sciences, Libin Cardiovascular Institute of Alberta, 3280 Hospital Dr., University of Calgary, Calgary, AB, Canada
| | - D Peter Tieleman
- Centre for Molecular Simulation and Department of Biological Sciences, 507 Campus Drive, University of Calgary, Calgary, AB, Canada.
| | - Henry J Duff
- Department of Cardiac Sciences, Libin Cardiovascular Institute of Alberta, 3280 Hospital Dr., University of Calgary, Calgary, AB, Canada.
| | - Sergei Yu Noskov
- Centre for Molecular Simulation and Department of Biological Sciences, 507 Campus Drive, University of Calgary, Calgary, AB, Canada.
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6
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Li L, Dai W, Li W, Zhang Y, Wu Y, Guan C, Zhang A, Huang H, Li Y. Integrated Network Pharmacology and Metabonomics to Reveal the Myocardial Protection Effect of Huang-Lian-Jie-Du-Tang on Myocardial Ischemia. Front Pharmacol 2021; 11:589175. [PMID: 33613277 PMCID: PMC7890363 DOI: 10.3389/fphar.2020.589175] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Accepted: 12/02/2020] [Indexed: 12/14/2022] Open
Abstract
Myocardial ischemia (MI) is one of the most common cardiovascular diseases with high incidence and mortality. Huang-Lian-Jie-Du-Tang (HLJDT) is a classic traditional Chinese prescription to clear “heat” and “poison”. In this study, we used a deliberate strategy integrating the methods of network pharmacology, pharmacodynamics, and metabonomics to investigate the molecular mechanism and potential targets of HLJDT in the treatment of MI. Firstly, by a network pharmacology approach, a global view of the potential compound-target-pathway network based on network pharmacology was constructed to provide a preliminary understanding of bioactive compounds and related targets of HLJDT for elucidating its molecular mechanisms in MI. Subsequently, in vivo efficacy of HLJDT was validated in a rat model. Meanwhile, the corresponding metabonomic profiles were used to explore differentially induced metabolic markers thus providing the metabolic mechanism of HLJDT in treating MI. The results demonstrated the myocardial protection effect of HLJDT on ischemia by a multicomponent-multitarget mode. This study highlights the reliability and effectiveness of a network pharmacology-based approach that identifies and validates the complex of natural compounds in HLJDT for illustrating the mechanism for the treatment of MI.
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Affiliation(s)
- Li Li
- Department of Pharmacy, The Eighth Affiliated Hospital, Sun Yat-sen University, Shenzhen, China
| | - Weixing Dai
- Department of Chemical and Biological Engineering, Hong Kong University of Science and Technology, Kowloon, China
| | - Wenting Li
- Department of Pharmacy, The Eighth Affiliated Hospital, Sun Yat-sen University, Shenzhen, China
| | - Yumao Zhang
- Department of Pharmacy, The Eighth Affiliated Hospital, Sun Yat-sen University, Shenzhen, China
| | - Yanqin Wu
- Department of Pharmacy, The Eighth Affiliated Hospital, Sun Yat-sen University, Shenzhen, China
| | - Chenfeng Guan
- Department of Pharmacy, The Eighth Affiliated Hospital, Sun Yat-sen University, Shenzhen, China
| | - Anye Zhang
- Department of Gastroenterology, The Eighth Affiliated Hospital, Sun Yat-sen University, Shenzhen, China
| | - Hui Huang
- Department of Cardiovascular, The Eighth Affiliated Hospital, Sun Yat-sen University, Shenzhen, China
| | - Yuzhen Li
- Department of Pharmacy, The Eighth Affiliated Hospital, Sun Yat-sen University, Shenzhen, China
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7
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Kovilakath A, Cowart LA. Sphingolipid Mediators of Myocardial Pathology. J Lipid Atheroscler 2020; 9:23-49. [PMID: 32821720 PMCID: PMC7379069 DOI: 10.12997/jla.2020.9.1.23] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2019] [Revised: 09/25/2019] [Accepted: 10/09/2019] [Indexed: 12/15/2022] Open
Abstract
Cardiomyopathy is the leading cause of mortality worldwide. While the causes of cardiomyopathy continue to be elucidated, current evidence suggests that aberrant bioactive lipid signaling plays a crucial role as a component of cardiac pathophysiology. Sphingolipids have been implicated in the pathophysiology of cardiovascular disease, as they regulate numerous cellular processes that occur in primary and secondary cardiomyopathies. Experimental evidence gathered over the last few decades from both in vitro and in vivo model systems indicates that inhibitors of sphingolipid synthesis attenuate a variety of cardiomyopathic symptoms. In this review, we focus on various cardiomyopathies in which sphingolipids have been implicated and the potential therapeutic benefits that could be gained by targeting sphingolipid metabolism.
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Affiliation(s)
- Anna Kovilakath
- Department of Human and Molecular Genetics, Virginia Commonwealth University, Richmond, VA, USA
| | - L. Ashley Cowart
- Department of Biochemistry and Molecular Biology and the Massey Cancer Center, Virginia Commonwealth University, Richmond, VA, USA
- Hunter Holmes McGuire Veteran's Affairs Medical Center, Richmond, VA, USA
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8
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Shi Y, Yan C, Li Y, Zhang Y, Zhang G, Li M, Li B, Zhao X. Expression signature of miRNAs and the potential role of miR-195-5p in high-glucose-treated rat cardiomyocytes. J Biochem Mol Toxicol 2019; 34:e22423. [PMID: 31729781 DOI: 10.1002/jbt.22423] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2019] [Revised: 10/10/2019] [Accepted: 10/30/2019] [Indexed: 12/12/2022]
Abstract
MicroRNAs are endogenous small noncoding RNAs that posttranscriptionally regulate the expression of target genes and play crucial roles in diverse physiopathologic processes. In the current study, we examined the microRNA (miRNA) expression profile of high-glucose-treated neonatal rat cardiomyocytes and the potential mechanisms. Differentially expressed miRNAs were analyzed by a miRNA microarray and validated by a quantitative real-time polymerase chain reaction in high-glucose-treated rat cardiomyocytes. Based on the results of our previous study and the bioinformatics prediction, we identified miR-195-5p/SGK1/Nedd4-2/hERG as the top-ranked signal pathway in diabetes cell model in vitro. In summary, our present study provides novel insights into the regulatory mechanism of miR-195-5p/SGK1/Nedd4-2/hERG in rat cardiomyocytes under high-glucose stress, which may provide a novel idea for the development of diagnostic and therapeutic strategies for diabetic cardiomyopathy in the future.
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Affiliation(s)
- Yuanqi Shi
- Department of Cardiology, The First Affiliated Hospital of Harbin Medical University, Harbin, China
| | - Caichuan Yan
- Department of Pharmacology, College of Pharmacy, Harbin Medical University, Harbin, China.,Department of Cancer Molecular and Biology, Heilongjiang Academy of Medical Sciences, Harbin Medical University, Harbin, China
| | - Yang Li
- Department of Pharmacology, College of Pharmacy, Harbin Medical University, Harbin, China
| | - Yuhao Zhang
- Department of Pharmacology, College of Pharmacy, Harbin Medical University, Harbin, China
| | - Guocui Zhang
- Department of Pharmacology, College of Pharmacy, Harbin Medical University, Harbin, China
| | - Mingzhu Li
- Department of Pharmacology, College of Pharmacy, Harbin Medical University, Harbin, China
| | - Baoxin Li
- Department of Pharmacology, College of Pharmacy, Harbin Medical University, Harbin, China
| | - Xin Zhao
- Department of Pharmacology, College of Pharmacy, Harbin Medical University, Harbin, China
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Piscopo S, Brown ER. Zinc Oxide Nanoparticles and Voltage-Gated Human K v 11.1 Potassium Channels Interact through a Novel Mechanism. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2018; 14:e1703403. [PMID: 29479853 DOI: 10.1002/smll.201703403] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Revised: 01/12/2018] [Indexed: 06/08/2023]
Abstract
Membrane-nanoparticle interactions are important in determining the effects of manufactured nanomaterials on cell physiology and pathology. Here, silica, titanium, zinc, and magnesium oxide nanoparticles are screened against human hERG (Kv 11.1) voltage-gated potassium channels under a whole-cell voltage clamp. 10 µg mL-1 ZnO uniquely increases the amplitude of the steady-state current, decreases the rate of hERG current inactivation during steady-state depolarization, accelerates channel deactivation during resurgent tail currents, and shows no significant alteration of current activation rate or voltage dependence. In contrast, ZnCl2 causes increased current suppression with increasing concentration and fails to replicate the nanoparticle effect on decreasing inactivation. The results show a novel class of nanoparticle-biomembrane interaction involving channel gating rather than channel block, and have implications for the use of nanoparticles in biomedicine, drug delivery applications, and nanotoxicology.
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Affiliation(s)
- Stefania Piscopo
- Stazione Zoologica Anton Dohrn, Villa Comunale, 80121, Naples, Italy
| | - Euan R Brown
- Institute of Biological Chemistry, Biophysics and Bioengineering, William Perkin Building, School of Engineering and Physical Sciences, Heriot Watt University, Edinburgh, EH14 4AS, UK
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Trotta MC, Salerno M, Brigida AL, Monda V, Messina A, Fiore C, Avola R, Bernardini R, Sessa F, Marsala G, Zanghì GN, Messina G, D'Amico M, Di Filippo C. Inhibition of aldose-reductase-2 by a benzofuroxane derivative bf-5m increases the expression of kcne1, kcnq1 in high glucose cultured H9c2 cardiac cells and sudden cardiac death. Oncotarget 2017; 9:17257-17269. [PMID: 29707106 PMCID: PMC5915114 DOI: 10.18632/oncotarget.23270] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Accepted: 12/08/2017] [Indexed: 12/20/2022] Open
Abstract
Long QT syndrome (LQTS) is characterized by prolonged QT interval, leading to sudden cardiac death. Hyperglycemia is an important risk factor for LQTS, inhibiting the cardiac rapid component delayed rectifier K+ current (Iks), responsible for QT interval. We previously showed that the new ALR2 inhibitor BF-5m supplies cardioprotection from QT prolongation induced by high glucose concentration in the medium, reducing QT interval prolongation and preserving morphology. Here we investigated the effects of BF-5m on cell cytotoxicity and viability in H9c2 cells, and on cellular potassium ion channels expression. H9c2 cells were grown in medium with high glucose and high glucose plus the BF-5m by assessing the cytotoxic effects and the cell survival rate. In addition, KCNE1 and KCNQ1 expression in plasma and mitochondrial membranes were monitored. Also, the expression levels of miR-1 proved to suppress KCNQ1 and KCNE1, were analyzed. BF-5m treatment reduced the cytotoxic effects of high glucose on H9c2 cells by increasing cell survival rate and improving H9c2 morphology. Plasmatic KCNE1 and KCNQ1 expression levels were restored by BF-5m in H9c2 exposed to high glucose, down-regulating miR-1. These results suggest that BF-5m exerts cardioprotection from high glucose in rat heart ventricle H9c2 cells exposed to high glucose.
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Affiliation(s)
- Maria Consiglia Trotta
- Department of Experimental Medicine, Division of Pharmacology, University of Campania L. Vanvitelli, Naples, Italy
| | - Monica Salerno
- Department of Clinical and Experimental Medicine University of Foggia, Foggia, Italy
| | - Anna Lisa Brigida
- Department of Experimental Medicine, Division of Pharmacology, University of Campania L. Vanvitelli, Naples, Italy
| | - Vincenzo Monda
- Department of Experimental Medicine, Section of Human Physiology and Dietetic and Sport Medicine, University of Campania L. Vanvitelli, Naples, Italy
| | - Antonietta Messina
- Department of Experimental Medicine, Section of Human Physiology and Dietetic and Sport Medicine, University of Campania L. Vanvitelli, Naples, Italy
| | - Carmela Fiore
- Department of Clinical and Experimental Medicine University of Foggia, Foggia, Italy
| | - Roberto Avola
- Department of Biomedical and Biotecnological Sciences, University of Catania, Catania, Italy
| | - Renato Bernardini
- Department of Biomedical and Biotecnological Sciences, University of Catania, Catania, Italy
| | - Francesco Sessa
- Department of Clinical and Experimental Medicine University of Foggia, Foggia, Italy
| | - Gabriella Marsala
- Struttura Complessa di Farmacia, Azienda Ospedaliero-Universitaria, Ospedali Riuniti di Foggia, Foggia, Italy
| | - Guido N Zanghì
- Department of Surgery, Policlinico Vittorio Emanuele University Hospital, University of Catania, Catania, Sicily, Italy
| | - Giovanni Messina
- Department of Clinical and Experimental Medicine University of Foggia, Foggia, Italy
| | - Michele D'Amico
- Department of Experimental Medicine, Division of Pharmacology, University of Campania L. Vanvitelli, Naples, Italy
| | - Clara Di Filippo
- Department of Experimental Medicine, Division of Pharmacology, University of Campania L. Vanvitelli, Naples, Italy
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11
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Stöhr R, Kappel BA, Carnevale D, Cavalera M, Mavilio M, Arisi I, Fardella V, Cifelli G, Casagrande V, Rizza S, Cattaneo A, Mauriello A, Menghini R, Lembo G, Federici M. TIMP3 interplays with apelin to regulate cardiovascular metabolism in hypercholesterolemic mice. Mol Metab 2015; 4:741-52. [PMID: 26500845 PMCID: PMC4588459 DOI: 10.1016/j.molmet.2015.07.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Revised: 07/23/2015] [Accepted: 07/27/2015] [Indexed: 11/18/2022] Open
Abstract
OBJECTIVE Tissue inhibitor of metalloproteinase 3 (TIMP3) is an extracellular matrix (ECM) bound protein, which has been shown to be downregulated in human subjects and experimental models with cardiometabolic disorders, including type 2 diabetes mellitus, hypertension and atherosclerosis. The aim of this study was to investigate the effects of TIMP3 on cardiac energy homeostasis during increased metabolic stress conditions. METHODS ApoE(-/-)TIMP3(-/-) and ApoE(-/-) mice on a C57BL/6 background were subjected to telemetric ECG analysis and experimental myocardial infarction as models of cardiac stress induction. We used Western blot, qRT-PCR, histology, metabolomics, RNA-sequencing and in vivo phenotypical analysis to investigate the molecular mechanisms of altered cardiac energy metabolism. RESULTS ApoE(-/-)TIMP3(-/-) revealed decreased lifespan. Telemetric ECG analysis showed increased arrhythmic episodes, and experimental myocardial infarction by left anterior descending artery (LAD) ligation resulted in increased peri-operative mortality together with increased scar formation, ventricular dilatation and a reduction of cardiac function after 4 weeks in the few survivors. Hearts of ApoE(-/-)TIMP3(-/-) exhibited accumulation of neutral lipids when fed a chow diet, which was exacerbated by a high fat, high cholesterol diet. Metabolomics analysis revealed an increase in circulating markers of oxidative stress with a reduction in long chain fatty acids. Using whole heart mRNA sequencing, we identified apelin as a putative modulator of these metabolic defects. Apelin is a regulator of fatty acid oxidation, and we found a reduction in the levels of enzymes involved in fatty acid oxidation in the left ventricle of ApoE(-/-)TIMP3(-/-) mice. Injection of apelin restored the hitherto identified metabolic defects of lipid oxidation. CONCLUSION TIMP3 regulates lipid metabolism as well as oxidative stress response via apelin. These findings therefore suggest that TIMP3 maintains metabolic flexibility in the heart, particularly during episodes of increased cardiac stress.
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Affiliation(s)
- Robert Stöhr
- Department of Systems Medicine, University of Rome Tor Vergata, 00133 Rome, Italy
- Department of Internal Medicine I, University Hospital Aachen, Pauwelsstraße 30, 52074 Aachen, Germany
| | - Ben Arpad Kappel
- Department of Systems Medicine, University of Rome Tor Vergata, 00133 Rome, Italy
- Department of Internal Medicine I, University Hospital Aachen, Pauwelsstraße 30, 52074 Aachen, Germany
| | - Daniela Carnevale
- Department of Angiocardioneurology and Translational Medicine, IRCCS Neuromed, 86077 Pozzilli, IS, Italy
- Department of Molecular Medicine, Sapienza University of Rome, 00161 Rome, Italy
| | - Michele Cavalera
- Department of Systems Medicine, University of Rome Tor Vergata, 00133 Rome, Italy
| | - Maria Mavilio
- Department of Systems Medicine, University of Rome Tor Vergata, 00133 Rome, Italy
| | - Ivan Arisi
- Genomics Facility, European Brain Research Institute, Rome, Italy
| | - Valentina Fardella
- Department of Angiocardioneurology and Translational Medicine, IRCCS Neuromed, 86077 Pozzilli, IS, Italy
| | - Giuseppe Cifelli
- Department of Angiocardioneurology and Translational Medicine, IRCCS Neuromed, 86077 Pozzilli, IS, Italy
| | - Viviana Casagrande
- Department of Systems Medicine, University of Rome Tor Vergata, 00133 Rome, Italy
| | - Stefano Rizza
- Department of Systems Medicine, University of Rome Tor Vergata, 00133 Rome, Italy
| | - Antonino Cattaneo
- European Brain Research Institute, Rome, Italy
- Scuola Normale Superiore, Pisa, Italy
| | - Alessandro Mauriello
- Department of Biomedicine and Prevention, University of Rome Tor Vergata, 00133 Rome, Italy
| | - Rossella Menghini
- Department of Systems Medicine, University of Rome Tor Vergata, 00133 Rome, Italy
| | - Giuseppe Lembo
- Department of Angiocardioneurology and Translational Medicine, IRCCS Neuromed, 86077 Pozzilli, IS, Italy
| | - Massimo Federici
- Department of Systems Medicine, University of Rome Tor Vergata, 00133 Rome, Italy
- Center for Atherosclerosis, Department of Medicine, Policlinico Tor Vergata, 00133 Rome, Italy
- Corresponding author. Department of Systems Medicine, University of Rome “Tor Vergata”, Via Montpellier 1, 00133 Rome, Italy. Tel.: +39 06 72596889; fax: +39 06 72596890.
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Zhang KP, Yang BF, Li BX. Translational toxicology and rescue strategies of the hERG channel dysfunction: biochemical and molecular mechanistic aspects. Acta Pharmacol Sin 2014; 35:1473-84. [PMID: 25418379 PMCID: PMC4261120 DOI: 10.1038/aps.2014.101] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2014] [Accepted: 08/20/2014] [Indexed: 01/08/2023] Open
Abstract
The human ether-à-go-go related gene (hERG) potassium channel is an obligatory anti-target for drug development on account of its essential role in cardiac repolarization and its close association with arrhythmia. Diverse drugs have been removed from the market owing to their inhibitory activity on the hERG channel and their contribution to acquired long QT syndrome (LQTS). Moreover, mutations that cause hERG channel dysfunction may induce congenital LQTS. Recently, an increasing number of biochemical and molecular mechanisms underlying hERG-associated LQTS have been reported. In fact, numerous potential biochemical and molecular rescue strategies are hidden within the biogenesis and regulating network. So far, rescue strategies of hERG channel dysfunction and LQTS mainly include activators, blockers, and molecules that interfere with specific links and other mechanisms. The aim of this review is to discuss the rescue strategies based on hERG channel toxicology from the biochemical and molecular perspectives.
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Affiliation(s)
- Kai-ping Zhang
- Department of Pharmacology, Harbin Medical University, Harbin, China
- The State-Province Key Laboratories of Biomedicine-Pharmaceutics of China (Key Laboratory of Cardiovascular Research, Ministry of Education), China
| | - Bao-feng Yang
- Department of Pharmacology, Harbin Medical University, Harbin, China
- The State-Province Key Laboratories of Biomedicine-Pharmaceutics of China (Key Laboratory of Cardiovascular Research, Ministry of Education), China
| | - Bao-xin Li
- Department of Pharmacology, Harbin Medical University, Harbin, China
- The State-Province Key Laboratories of Biomedicine-Pharmaceutics of China (Key Laboratory of Cardiovascular Research, Ministry of Education), China
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Lipid metabolites and their differential pro-arrhythmic profiles: of importance in the development of a new anti-arrhythmic pharmacology. Mol Cell Biochem 2014; 393:191-7. [DOI: 10.1007/s11010-014-2060-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2013] [Accepted: 04/11/2014] [Indexed: 01/12/2023]
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Wang Q, Hu W, Lei M, Wang Y, Yan B, Liu J, Zhang R, Jin Y. MiR-17-5p impairs trafficking of H-ERG K+ channel protein by targeting multiple er stress-related chaperones during chronic oxidative stress. PLoS One 2013; 8:e84984. [PMID: 24386440 PMCID: PMC3875566 DOI: 10.1371/journal.pone.0084984] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2013] [Accepted: 11/29/2013] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND To investigate if microRNAs (miRNAs) play a role in regulating h-ERG trafficking in the setting of chronic oxidative stress as a common deleterious factor for many cardiac disorders. METHODS We treated neonatal rat ventricular myocytes and HEK293 cells with stable expression of h-ERG with H2O2 for 12 h and 48 h. Expression of miR-17-5p seed miRNAs was quantified by real-time RT-PCR. Protein levels of chaperones and h-ERG trafficking were measured by Western blot analysis. Luciferase reporter gene assay was used to study miRNA and target interactions. Whole-cell patch-clamp techniques were employed to record h-ERG K(+) current. RESULTS H-ERG trafficking was impaired by H2O2 after 48 h treatment, accompanied by reciprocal changes of expression between miR-17-5p seed miRNAs and several chaperones (Hsp70, Hsc70, CANX, and Golga2), with the former upregulated and the latter downregulated. We established these chaperones as targets for miR-17-5p. Application miR-17-5p inhibitor rescued H2O2-induced impairment of h-ERG trafficking. Upregulation of endogenous by H2O2 or forced miR-17-5p expression either reduced h-ERG current. Sequestration of AP1 by its decoy molecule eliminated the upregulation of miR-17-5p, and ameliorated impairment of h-ERG trafficking. CONCLUSIONS Collectively, deregulation of the miR-17-5p seed family miRNAs can cause severe impairment of h-ERG trafficking through targeting multiple ER stress-related chaperones, and activation of AP1 likely accounts for the deleterious upregulation of these miRNAs, in the setting of prolonged duration of oxidative stress. These findings revealed the role of miRNAs in h-ERG trafficking, which may contribute to the cardiac electrical disturbances associated with oxidative stress.
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Affiliation(s)
- Qi Wang
- The Fourth Affiliated Hospital of China Medical University, Shenyang, Liaoning Province, P. R. China
| | - Weina Hu
- The Fourth Affiliated Hospital of China Medical University, Shenyang, Liaoning Province, P. R. China
| | - Mingming Lei
- The Fourth Affiliated Hospital of China Medical University, Shenyang, Liaoning Province, P. R. China
| | - Yong Wang
- The Fourth Affiliated Hospital of China Medical University, Shenyang, Liaoning Province, P. R. China
| | - Bing Yan
- The Fourth Affiliated Hospital of China Medical University, Shenyang, Liaoning Province, P. R. China
| | - Jun Liu
- The Fourth Affiliated Hospital of China Medical University, Shenyang, Liaoning Province, P. R. China
| | - Ren Zhang
- The Fourth Affiliated Hospital of China Medical University, Shenyang, Liaoning Province, P. R. China
| | - Yuanzhe Jin
- The Fourth Affiliated Hospital of China Medical University, Shenyang, Liaoning Province, P. R. China
- * E-mail:
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Abstract
Reactive oxygen species (ROS) have been associated with various human diseases, and considerable attention has been paid to investigate their physiological effects. Various ROS are synthesized in the mitochondria and accumulate in the cytoplasm if the cellular antioxidant defense mechanism fails. The critical balance of this ROS synthesis and antioxidant defense systems is termed the redox system of the cell. Various cardiovascular diseases have also been affected by redox to different degrees. ROS have been indicated as both detrimental and protective, via different cellular pathways, for cardiac myocyte functions, electrophysiology, and pharmacology. Mostly, the ROS functions depend on the type and amount of ROS synthesized. While the literature clearly indicates ROS effects on cardiac contractility, their effects on cardiac excitability are relatively under appreciated. Cardiac excitability depends on the functions of various cardiac sarcolemal or mitochondrial ion channels carrying various depolarizing or repolarizing currents that also maintain cellular ionic homeostasis. ROS alter the functions of these ion channels to various degrees to determine excitability by affecting the cellular resting potential and the morphology of the cardiac action potential. Thus, redox balance regulates cardiac excitability, and under pathological regulation, may alter action potential propagation to cause arrhythmia. Understanding how redox affects cellular excitability may lead to potential prophylaxis or treatment for various arrhythmias. This review will focus on the studies of redox and cardiac excitation.
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Affiliation(s)
- Nitin T Aggarwal
- Division of Cardiovascular Medicine, Department of Medicine, University of Wisconsin, Madison, WI 53792, USA
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Babenko NA, Hassouneh LKM, Kharchenko VS, Garkavenko VV. Vitamin E prevents the age-dependent and palmitate-induced disturbances of sphingolipid turnover in liver cells. AGE (DORDRECHT, NETHERLANDS) 2012; 34:905-15. [PMID: 21796379 PMCID: PMC3682064 DOI: 10.1007/s11357-011-9288-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2010] [Accepted: 07/04/2011] [Indexed: 05/31/2023]
Abstract
Sphingolipid turnover has been shown to be activated at old age and in response to various stress stimuli including oxidative stress. Reduction of vitamin E content in the liver under the pro-oxidant action is associated with enhanced sphingolipid turnover and ceramide accumulation in hepatocytes. In the present paper, the correction of sphingolipid metabolism in the liver cells of old rats and in the palmitate-treated young hepatocytes using α-tocopherol has been investigated. 3- and 24-month-old rats, [(14) C]palmitic acid, [methyl-(14) C-choline]sphingomyelin (SM), and [(14) C]serine were used. α-Tocopherol administration to old rats or addition to the culture medium of old liver slices or hepatocytes prevented age-dependent increase of ceramide synthesis and lipid accumulation, and increased SM content in liver tissue and cells. α-Tocopherol treatment of old cells decreased the neutral and acid sphingomyelinase (SMase) activities in hepatocytes and serine palmitoyl transferase activity in the liver cell microsomes. Effect of α- or γ-tocopherol, but not of δ-tocopherol, on the newly synthesized ceramide content in old cells was correlated with the action of inhibitor of serine palmitoyl transferase (SPT) activity (myriocin) and SMase inhibitors (glutathione, imipramine). Addition of α-tocopherol as well as myriocin to the culture medium of young hepatocytes, treated by palmitate, abolished ceramide accumulation and synthesis. The data obtained demonstrate that α-tocopherol normalized elevated ceramide content in the old liver cells via inhibition of acid and neutral SMase activities and lipid synthesis de novo. α-Tocopherol, reducing ceramide synthesis, prevented palmitate-induced aging-like ceramide accumulation in young liver cells.
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Affiliation(s)
- Nataliya A Babenko
- Department of Physiology of Ontogenesis, Institute of Biology, Kharkov Karazin National University, 4 Svobody pl., Kharkov, Ukraine.
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Vandenberg JI, Perry MD, Perrin MJ, Mann SA, Ke Y, Hill AP. hERG K+ Channels: Structure, Function, and Clinical Significance. Physiol Rev 2012; 92:1393-478. [DOI: 10.1152/physrev.00036.2011] [Citation(s) in RCA: 463] [Impact Index Per Article: 38.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
The human ether-a-go-go related gene (hERG) encodes the pore-forming subunit of the rapid component of the delayed rectifier K+ channel, Kv11.1, which are expressed in the heart, various brain regions, smooth muscle cells, endocrine cells, and a wide range of tumor cell lines. However, it is the role that Kv11.1 channels play in the heart that has been best characterized, for two main reasons. First, it is the gene product involved in chromosome 7-associated long QT syndrome (LQTS), an inherited disorder associated with a markedly increased risk of ventricular arrhythmias and sudden cardiac death. Second, blockade of Kv11.1, by a wide range of prescription medications, causes drug-induced QT prolongation with an increase in risk of sudden cardiac arrest. In the first part of this review, the properties of Kv11.1 channels, including biogenesis, trafficking, gating, and pharmacology are discussed, while the second part focuses on the pathophysiology of Kv11.1 channels.
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Affiliation(s)
- Jamie I. Vandenberg
- Mark Cowley Lidwill Research Programme in Cardiac Electrophysiology, Victor Chang Cardiac Research Institute, Sydney, New South Wales, Australia; St Vincent's Clinical School, University of New South Wales, New South Wales, Australia; and University of Ottawa Heart Institute, Ottawa, Canada
| | - Matthew D. Perry
- Mark Cowley Lidwill Research Programme in Cardiac Electrophysiology, Victor Chang Cardiac Research Institute, Sydney, New South Wales, Australia; St Vincent's Clinical School, University of New South Wales, New South Wales, Australia; and University of Ottawa Heart Institute, Ottawa, Canada
| | - Mark J. Perrin
- Mark Cowley Lidwill Research Programme in Cardiac Electrophysiology, Victor Chang Cardiac Research Institute, Sydney, New South Wales, Australia; St Vincent's Clinical School, University of New South Wales, New South Wales, Australia; and University of Ottawa Heart Institute, Ottawa, Canada
| | - Stefan A. Mann
- Mark Cowley Lidwill Research Programme in Cardiac Electrophysiology, Victor Chang Cardiac Research Institute, Sydney, New South Wales, Australia; St Vincent's Clinical School, University of New South Wales, New South Wales, Australia; and University of Ottawa Heart Institute, Ottawa, Canada
| | - Ying Ke
- Mark Cowley Lidwill Research Programme in Cardiac Electrophysiology, Victor Chang Cardiac Research Institute, Sydney, New South Wales, Australia; St Vincent's Clinical School, University of New South Wales, New South Wales, Australia; and University of Ottawa Heart Institute, Ottawa, Canada
| | - Adam P. Hill
- Mark Cowley Lidwill Research Programme in Cardiac Electrophysiology, Victor Chang Cardiac Research Institute, Sydney, New South Wales, Australia; St Vincent's Clinical School, University of New South Wales, New South Wales, Australia; and University of Ottawa Heart Institute, Ottawa, Canada
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Yun J, Bae H, Choi SE, Kim JH, Choi YW, Lim I, Lee CS, Lee MW, Ko JH, Seo SJ, Bang H. Hirsutenone directly blocks human ether-a-go-go related gene K+ channels. Biol Pharm Bull 2012; 34:1815-22. [PMID: 22130236 DOI: 10.1248/bpb.34.1815] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The aim of the present study was to investigate whether hirsutenone affects the human ether-a-go-go related gene (hERG) K(+) channels. Many drugs promote formation of the acquired form of long QT syndrome (LQTS) by blocking the hERG K(+) channels. Hirsutenone, a new candidate for the treatment inflammatory skin lesions, induced a concentration-dependent decrease in hERG K(+) current amplitudes. Hirsutenone significantly decreased the time constants at the onset of inactivation. However, the reductions in the time constants of steady-state inactivation and the recovery from inactivation after hirsutenone treatment were not significant. In addition, the drug had no effect on the voltage-dependent activation curve or the steady-state inactivation curve. In summary, hirsutenone potentially acts as a blocker of hERG K(+) channels functioning by modifying the channel inactivation kinetics.
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Affiliation(s)
- Jihyun Yun
- Department of Physiology, College of Medicine, Chung-Ang University, Seoul 156–756, Korea
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Lang F, Ullrich S, Gulbins E. Ceramide formation as a target in beta-cell survival and function. Expert Opin Ther Targets 2011; 15:1061-71. [PMID: 21635197 DOI: 10.1517/14728222.2011.588209] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
INTRODUCTION Ceramide may be synthesized de novo or generated by sphingomyelinase-dependent hydrolysis of sphingomyelin. AREAS COVERED The role of ceramide, ceramide-sensitive signaling and ion channels in β-cell apoptosis, lipotoxicity and amyloid-induced β-cell death. EXPERT OPINION Ceramide participates in β-cell dysfunction and apoptosis after exposure to TNFα, IL-1β and IFN-γ, excessive amyloid and islet amyloid polypeptide or non-esterified fatty acids (lipotoxicity). Knockout of sphingomyelin synthase 1, which converts ceramide to sphingomyelin, leads to impairment of insulin secretion. Increased ceramidase activity or pharmacological inhibition of ceramide synthetase, inhibits β-cell apoptosis. Ceramide contributes to endoplasmatic reticulum (ER) stress, decreased mitochondrial membrane potential in insulin-secreting cells and mitochondrial release of cytochrome c into the cytosol, which are all triggers of apoptotic cell death. Ceramide-dependent signaling involves activation of extracellularly regulated kinases 1 and 2 (ERK1/2), downregulation of Period (Per)-aryl hydrocarbon receptor nuclear translocator (Arnt)-single-minded (Sim) kinase (PASK), activation of okadaic-acid-sensitive protein phosphatase 2A (PP2A) and stimulation of NADPH-oxidase with generation of superoxides and lipid peroxides. Ceramide reduces the activity of voltage gated potassium (Kv)-channels in insulin-secreting cells. The role of ceramide in β-cell survival and function may be therapeutically relevant, because ceramide formation can be suppressed by pharmacological inhibition of ceramide synthetase and/or sphingomyelinase.
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Affiliation(s)
- Florian Lang
- University of Tübingen, Institute of Physiology, Germany.
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Kolbe K, Schönherr R, Gessner G, Sahoo N, Hoshi T, Heinemann SH. Cysteine 723 in the C-linker segment confers oxidative inhibition of hERG1 potassium channels. J Physiol 2010; 588:2999-3009. [PMID: 20547678 DOI: 10.1113/jphysiol.2010.192468] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Excess reactive oxygen species (ROS) play a crucial role under pathophysiological conditions, such as ischaemia/reperfusion and diabetes, potentially contributing to cardiac arrhythmia. hERG1 (KCNH2) potassium channels terminate the cardiac action potential and malfunction can lead to long-QT syndrome and fatal arrhythmia. To investigate the molecular mechanisms of hERG1 channel alteration by ROS, hERG1 and mutants thereof were expressed in HEK293 cells and studied with the whole-cell patch-clamp method. Even mild ROS stress induced by hyperglycaemia markedly decreased channel current. Intracellular H2O2 or cysteine-specific modifiers also strongly inhibited channel activity and accelerated deactivation kinetics. Mutagenesis revealed that cysteine 723 (C723), a conserved residue in a structural element linking the C-terminal domain to the channel's gate, is critical for oxidative functional modification. Moreover, kinetics of channel closure strongly influences ROS-induced modification, where rapid channel deactivation diminishes ROS sensitivity. Because of its fast deactivation kinetics, the N-terminally truncated splice variant hERG1b possesses greater resistance to oxidative modification.
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Affiliation(s)
- Katrin Kolbe
- Centre for Molecular Biomedicine, Department of Biophysics, Friedrich Schiller University of Jena, Hans-Knöll-Str. 2, D-07745 Jena, Germany
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Ganapathi SB, Fox TE, Kester M, Elmslie KS. Ceramide modulates HERG potassium channel gating by translocation into lipid rafts. Am J Physiol Cell Physiol 2010; 299:C74-86. [PMID: 20375276 DOI: 10.1152/ajpcell.00462.2009] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Human ether-à-go-go-related gene (HERG) potassium channels play an important role in cardiac action potential repolarization, and HERG dysfunction can cause cardiac arrhythmias. However, recent evidence suggests a role for HERG in the proliferation and progression of multiple types of cancers, making it an attractive target for cancer therapy. Ceramide is an important second messenger of the sphingolipid family, which due to its proapoptotic properties has shown promising results in animal models as an anticancer agent. Yet the acute effects of ceramide on HERG potassium channels are not known. In the present study we examined the effects of cell-permeable C(6)-ceramide on HERG potassium channels stably expressed in HEK-293 cells. C(6)-ceramide (10 microM) reversibly inhibited HERG channel current (I(HERG)) by 36 +/- 5%. Kinetically, ceramide induced a significant hyperpolarizing shift in the current-voltage relationship (DeltaV(1/2) = -8 +/- 0.5 mV) and increased the deactivation rate (43 +/- 3% for tau(fast) and 51 +/- 3% for tau(slow)). Mechanistically, ceramide recruited HERG channels within caveolin-enriched lipid rafts. Cholesterol depletion and repletion experiments and mathematical modeling studies confirmed that inhibition and gating effects are mediated by separate mechanisms. The ceramide-induced hyperpolarizing gating shift (raft mediated) could offset the impact of inhibition (raft independent) during cardiac action potential repolarization, so together they may nullify any negative impact on cardiac rhythm. Our results provide new insights into the effects of C(6)-ceramide on HERG channels and suggest that C(6)-ceramide can be a promising therapeutic for cancers that overexpress HERG.
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Affiliation(s)
- Sindura B Ganapathi
- Department of Pharmacology, Pennsylvania State College of Medicine, Hershey, PA 17033, USA
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22
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Raucci FJ, Wijesinghe DS, Chalfant CE, Baumgarten CM. Exogenous and endogenous ceramides elicit volume-sensitive chloride current in ventricular myocytes. Cardiovasc Res 2009; 86:55-62. [PMID: 20008476 DOI: 10.1093/cvr/cvp399] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
AIMS Because ceramide accumulates in several forms of cardiovascular disease and ceramide-induced apoptosis may involve the volume-sensitive Cl(-) current, I(Cl,swell), we assessed whether ceramide activates I(Cl,swell). METHODS AND RESULTS I(Cl,swell) was measured in rabbit ventricular myocytes by whole-cell patch clamp after isolating anion currents. Exogenous C(2)-ceramide (C(2)-Cer), a membrane-permeant short-chain ceramide, elicited an outwardly rectifying Cl(-) current in both physiological and symmetrical Cl(-) solutions that was fully inhibited by DCPIB, a specific I(Cl,swell) blocker. In contrast, the metabolically inactive C(2)-Cer analogue C(2)-dihydroceramide (C(2)-H(2)Cer) failed to activate Cl(-) current. Bacterial sphingomyelinase (SMase), which generates endogenous long-chain ceramides as was confirmed by tandem mass spectrometry, also elicited an outwardly rectifying Cl(-) current that was inhibited by DCPIB and tamoxifen, another I(Cl,swell) blocker. Bacterial SMase-induced current was partially reversed by osmotic shrinkage and fully suppressed by ebselen, a scavenger of reactive oxygen species. Outward rectification with physiological and symmetrical Cl(-) gradients, block by DCPIB and tamoxifen, and volume sensitivity are characteristics that identify I(Cl,swell). Insensitivity to C(2)-H(2)Cer and block by ebselen suggest involvement of ceramide signalling rather than direct lipid-channel interaction. CONCLUSION Exogenous and endogenous ceramide elicited I(Cl,swell) in ventricular myocytes. This may contribute to persistent activation of I(Cl,swell) and aspects of altered myocyte function in cardiovascular diseases associated with by ceramide accumulation.
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Affiliation(s)
- Frank J Raucci
- Department of Physiology and Biophysics, Medical College of Virginia, Virginia Commonwealth University, 1101 East Marshall Street, PO Box 980551, Richmond, VA 23298-0551, USA
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Sphingomyelinase dependent apoptosis following treatment of pancreatic beta-cells with amyloid peptides Aß1-42 or IAPP. Apoptosis 2009; 14:878-89. [DOI: 10.1007/s10495-009-0364-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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Kaur P, Schulz K, Heggland I, Aschner M, Syversen T. The use of fluorescence for detecting MeHg-induced ROS in cell cultures. Toxicol In Vitro 2008; 22:1392-8. [DOI: 10.1016/j.tiv.2008.01.017] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2007] [Revised: 01/23/2008] [Accepted: 01/31/2008] [Indexed: 11/16/2022]
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Holland WL, Summers SA. Sphingolipids, insulin resistance, and metabolic disease: new insights from in vivo manipulation of sphingolipid metabolism. Endocr Rev 2008; 29:381-402. [PMID: 18451260 PMCID: PMC2528849 DOI: 10.1210/er.2007-0025] [Citation(s) in RCA: 428] [Impact Index Per Article: 26.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Obesity and dyslipidemia are risk factors for metabolic disorders including diabetes and cardiovascular disease. Sphingolipids such as ceramide and glucosylceramides, while being a relatively minor component of the lipid milieu in most tissues, may be among the most pathogenic lipids in the onset of the sequelae associated with excess adiposity. Circulating factors associated with obesity (e.g., saturated fatty acids, inflammatory cytokines) selectively induce enzymes that promote sphingolipid synthesis, and lipidomic profiling reveals relationships between tissue sphingolipid levels and certain metabolic diseases. Moreover, studies in cultured cells and isolated tissues implicate sphingolipids in certain cellular events associated with diabetes and cardiovascular disease, including insulin resistance, pancreatic beta-cell failure, cardiomyopathy, and vascular dysfunction. However, definitive evidence that sphingolipids contribute to insulin resistance, diabetes, and atherosclerosis has come only recently, as researchers have found that pharmacological inhibition or genetic ablation of enzymes controlling sphingolipid synthesis in rodents ameliorates each of these conditions. Herein we will review the role of ceramide and other sphingolipid metabolites in insulin resistance, beta-cell failure, cardiomyopathy, and vascular dysfunction, focusing on these in vivo studies that identify enzymes controlling sphingolipid metabolism as therapeutic targets for combating metabolic disease.
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Affiliation(s)
- William L Holland
- Division of Endocrinology, Metabolism, and Diabetes, Department of Internal Medicine, University of Utah, Salt Lake City, Utah 84132, USA
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