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Wu Q, Wang Y, Liu J, Guan X, Chang X, Liu Z, Liu R. Microtubules and cardiovascular diseases: insights into pathology and therapeutic strategies. Int J Biochem Cell Biol 2024; 175:106650. [PMID: 39237031 DOI: 10.1016/j.biocel.2024.106650] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2024] [Revised: 08/25/2024] [Accepted: 08/31/2024] [Indexed: 09/07/2024]
Abstract
Microtubules, complex cytoskeletal structures composed of tubulin proteins in eukaryotic cells, have garnered recent attention in cardiovascular research. Investigations have focused on the post-translational modifications of tubulin, including acetylation and detyrosination. Perturbations in microtubule homeostasis have been implicated in various pathological processes associated with cardiovascular diseases such as heart failure, ischemic heart disease, and arrhythmias. Thus, elucidating the intricate interplay between microtubule dynamics and cardiovascular pathophysiology is imperative for advancing preventive and therapeutic strategies. Several natural compounds have been identified to potentially modulate microtubules, thereby exerting regulatory effects on cardiovascular diseases. This review synthesizes current literature to delineate the roles of microtubules in cardiovascular diseases and assesses the potential of natural compounds in microtubule-targeted therapies.
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Affiliation(s)
- Qiaomin Wu
- Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing 100053, China
| | - Yanli Wang
- Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing 100053, China
| | - Jinfeng Liu
- Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing 100053, China
| | - Xuanke Guan
- Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing 100053, China
| | - Xing Chang
- Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing 100053, China.
| | - Zhiming Liu
- Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing 100053, China
| | - Ruxiu Liu
- Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing 100053, China.
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Nasilli G, de Waal TM, Marchal GA, Bertoli G, Veldkamp MW, Rothenberg E, Casini S, Remme CA. Decreasing microtubule detyrosination modulates Nav1.5 subcellular distribution and restores sodium current in mdx cardiomyocytes. Cardiovasc Res 2024; 120:723-734. [PMID: 38395031 PMCID: PMC11135645 DOI: 10.1093/cvr/cvae043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Revised: 11/28/2023] [Accepted: 01/08/2024] [Indexed: 02/25/2024] Open
Abstract
AIMS The microtubule (MT) network plays a major role in the transport of the cardiac sodium channel Nav1.5 to the membrane, where the latter associates with interacting proteins such as dystrophin. Alterations in MT dynamics are known to impact on ion channel trafficking. Duchenne muscular dystrophy (DMD), caused by dystrophin deficiency, is associated with an increase in MT detyrosination, decreased sodium current (INa), and arrhythmias. Parthenolide (PTL), a compound that decreases MT detyrosination, has shown beneficial effects on cardiac function in DMD. We here investigated its impact on INa and Nav1.5 subcellular distribution. METHODS AND RESULTS Ventricular cardiomyocytes (CMs) from wild-type (WT) and mdx (DMD) mice were incubated with either 10 µM PTL, 20 µM EpoY, or dimethylsulfoxide (DMSO) for 3-5 h, followed by patch-clamp analysis to assess INa and action potential (AP) characteristics in addition to immunofluorescence and stochastic optical reconstruction microscopy (STORM) to investigate MT detyrosination and Nav1.5 cluster size and density, respectively. In accordance with previous studies, we observed increased MT detyrosination, decreased INa and reduced AP upstroke velocity (Vmax) in mdx CMs compared to WT. PTL decreased MT detyrosination and significantly increased INa magnitude (without affecting INa gating properties) and AP Vmax in mdx CMs, but had no effect in WT CMs. Moreover, STORM analysis showed that in mdx CMs, Nav1.5 clusters were decreased not only in the grooves of the lateral membrane (LM; where dystrophin is localized) but also at the LM crests. PTL restored Nav1.5 clusters at the LM crests (but not at the grooves), indicating a dystrophin-independent trafficking route to this subcellular domain. Interestingly, Nav1.5 cluster density was also reduced at the intercalated disc (ID) region of mdx CMs, which was restored to WT levels by PTL. Treatment of mdx CMs with EpoY, a specific MT detyrosination inhibitor, also increased INa density, while decreasing the amount of detyrosinated MTs, confirming a direct mechanistic link. CONCLUSION Attenuating MT detyrosination in mdx CMs restored INa and enhanced Nav1.5 localization at the LM crest and ID. Hence, the reduced whole-cell INa density characteristic of mdx CMs is not only the consequence of the lack of dystrophin within the LM grooves but is also due to reduced Nav1.5 at the LM crest and ID secondary to increased baseline MT detyrosination. Overall, our findings identify MT detyrosination as a potential therapeutic target for modulating INa and subcellular Nav1.5 distribution in pathophysiological conditions.
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Affiliation(s)
- Giovanna Nasilli
- Department of Experimental Cardiology, Amsterdam University Medical Center, University of Amsterdam, Heart Centre, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands
- Amsterdam Cardiovascular Sciences, Heart Failure & Arrhythmias, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands
- Division of Cardiology, NYU Grossman School of Medicine, 550 First Avenue, New York, NY 10016, USA
| | - Tanja M de Waal
- Department of Experimental Cardiology, Amsterdam University Medical Center, University of Amsterdam, Heart Centre, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands
- Amsterdam Cardiovascular Sciences, Heart Failure & Arrhythmias, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands
| | - Gerard A Marchal
- Department of Experimental Cardiology, Amsterdam University Medical Center, University of Amsterdam, Heart Centre, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands
- Amsterdam Cardiovascular Sciences, Heart Failure & Arrhythmias, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands
| | - Giorgia Bertoli
- Division of Cardiology, NYU Grossman School of Medicine, 550 First Avenue, New York, NY 10016, USA
| | - Marieke W Veldkamp
- Department of Experimental Cardiology, Amsterdam University Medical Center, University of Amsterdam, Heart Centre, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands
- Amsterdam Cardiovascular Sciences, Heart Failure & Arrhythmias, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands
| | - Eli Rothenberg
- Department of Biochemistry and Pharmacology, NYU Grossman School of Medicine, 450 E 29TH ST Alexandria Center for Life Science, New York, NY 10016, USA
| | - Simona Casini
- Department of Experimental Cardiology, Amsterdam University Medical Center, University of Amsterdam, Heart Centre, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands
- Amsterdam Cardiovascular Sciences, Heart Failure & Arrhythmias, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands
| | - Carol Ann Remme
- Department of Experimental Cardiology, Amsterdam University Medical Center, University of Amsterdam, Heart Centre, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands
- Amsterdam Cardiovascular Sciences, Heart Failure & Arrhythmias, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands
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Actin-microtubule cytoskeletal interplay mediated by MRTF-A/SRF signaling promotes dilated cardiomyopathy caused by LMNA mutations. Nat Commun 2022; 13:7886. [PMID: 36550158 PMCID: PMC9780334 DOI: 10.1038/s41467-022-35639-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Accepted: 12/14/2022] [Indexed: 12/24/2022] Open
Abstract
Mutations in the lamin A/C gene (LMNA) cause dilated cardiomyopathy associated with increased activity of ERK1/2 in the heart. We recently showed that ERK1/2 phosphorylates cofilin-1 on threonine 25 (phospho(T25)-cofilin-1) that in turn disassembles the actin cytoskeleton. Here, we show that in muscle cells carrying a cardiomyopathy-causing LMNA mutation, phospho(T25)-cofilin-1 binds to myocardin-related transcription factor A (MRTF-A) in the cytoplasm, thus preventing the stimulation of serum response factor (SRF) in the nucleus. Inhibiting the MRTF-A/SRF axis leads to decreased α-tubulin acetylation by reducing the expression of ATAT1 gene encoding α-tubulin acetyltransferase 1. Hence, tubulin acetylation is decreased in cardiomyocytes derived from male patients with LMNA mutations and in heart and isolated cardiomyocytes from Lmnap.H222P/H222P male mice. In Atat1 knockout mice, deficient for acetylated α-tubulin, we observe left ventricular dilation and mislocalization of Connexin 43 (Cx43) in heart. Increasing α-tubulin acetylation levels in Lmnap.H222P/H222P mice with tubastatin A treatment restores the proper localization of Cx43 and improves cardiac function. In summary, we show for the first time an actin-microtubule cytoskeletal interplay mediated by cofilin-1 and MRTF-A/SRF, promoting the dilated cardiomyopathy caused by LMNA mutations. Our findings suggest that modulating α-tubulin acetylation levels is a feasible strategy for improving cardiac function.
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Lv Z, Chen X, Chen P, Li Q, Guo Z, Lu Q, Ding S. Colchicine prevents ventricular arrhythmias vulnerability in diet-induced obesity rats. Biochem Biophys Res Commun 2022; 610:127-132. [PMID: 35462093 DOI: 10.1016/j.bbrc.2022.03.114] [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: 03/16/2022] [Accepted: 03/22/2022] [Indexed: 11/02/2022]
Abstract
AIMS This study aimed to assess the role of colchicine in ventricular arrhythmias (VAs) induced by high fat diet (HFD)-fed rats. METHODS AND RESULTS Male rats were divided into four groups: CTL, normal diet plus saline; CTC, normal diet plus colchicine; HFD, HFD plus saline; HFC: HFD plus colchicine. Metabolic parameters, ECG parameters, ventricular electrophysiological parameters, ventricular histology, Western blot and RT-qPCR were measured. Compared with the HFD group, colchicine treatment significantly improved metabolic parameters, reduced ventricular fibrosis, increased the expression of Cav1.2, Kv4.2, Nav1.5, and Cx43, reduced CaMKII, p-CaMKII, p-RyR2 (S2808), and p-RyR2 (S2814) expression in LV. Furthermore, colchicine inhibited the inflammatory responses, prolonged ventricular effective refractory period (ERP), reduced corrected QT interval (QTc) and Tpeak-Tend interval, so as to reduce the susceptibility to VAs in obesity rats. CONCLUSIONS Colchicine could mitigate ventricular fibrosis, ventricular electrical remodeling, as well as the expression of ion channels, and inhibit obesity-induced inflammatory responses, which provides a new idea for colchicine to prevent VAs in obese individuals.
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Affiliation(s)
- Zhiyang Lv
- The First School of Clinical Medicine, Southern Medical University, Guangzhou, 510515, PR China; Institute of Cardiovascular Diseases, The First College of Clinical Medical Sciences, China Three Gorges University, Yichang, 443003, PR China
| | - Xiaodi Chen
- Department of Ultrasound, The First College of Clinical Medical Sciences, China Three Gorges University, Yichang, 443003, PR China
| | - Ping Chen
- National Standardized Training Base for Resident, The First College of Clinical Medical Sciences, China Three Gorges University, Yichang, 443003, PR China
| | - Qianyuan Li
- Clinical Laboratory, The First College of Clinical Medical Sciences, China Three Gorges University, Yichang, 443003, PR China
| | - Zhuli Guo
- Institute of Cardiovascular Diseases, The First College of Clinical Medical Sciences, China Three Gorges University, Yichang, 443003, PR China
| | - Qing Lu
- Department of Cardiology, General Hospital of Central Theater Command, Wuhan Clinical Medicine College of Southern Medical University, Wuhan, 430070, PR China
| | - Shifang Ding
- The First School of Clinical Medicine, Southern Medical University, Guangzhou, 510515, PR China; Department of Cardiology, General Hospital of Central Theater Command, Wuhan Clinical Medicine College of Southern Medical University, Wuhan, 430070, PR China.
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Li E, Loen V, van Ham WB, Kool W, van der Heyden MAG, Takanari H. Quantitative Analysis of the Cytoskeleton's Role in Inward Rectifier K IR 2.1 Forward and Backward Trafficking. Front Physiol 2022; 12:812572. [PMID: 35145427 PMCID: PMC8821923 DOI: 10.3389/fphys.2021.812572] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Accepted: 12/23/2021] [Indexed: 11/13/2022] Open
Abstract
Alteration of the inward rectifier current IK1, carried by KIR2.1 channels, affects action potential duration, impacts resting membrane stability and associates with cardiac arrhythmias. Congenital and acquired KIR2.1 malfunction frequently associates with aberrant ion channel trafficking. Cellular processes underlying trafficking are intertwined with cytoskeletal function. The extent to which the cytoskeleton is involved in KIR2.1 trafficking processes is unknown. We aimed to quantify the dependence of KIR2.1 trafficking on cytoskeleton function. GFP or photoconvertible Dendra2 tagged KIR2.1 constructs were transfected in HEK293 or HeLa cells. Photoconversion of the Dendra2 probe at the plasma membrane and subsequent live imaging of trafficking processes was performed by confocal laser-scanning microscopy. Time constant of green fluorescent recovery (τg,s) represented recruitment of new KIR2.1 at the plasma membrane. Red fluorescent decay (τr,s) represented internalization of photoconverted KIR2.1. Patch clamp electrophysiology was used to quantify IKIR2.1. Biochemical methods were used for cytoskeleton isolation and detection of KIR2.1-cytoskeleton interactions. Cytochalasin B (20 μM), Nocodazole (30 μM) and Dyngo-4a (10 nM) were used to modify the cytoskeleton. Chloroquine (10 μM, 24 h) was used to impair KIR2.1 breakdown. Cytochalasin B and Nocodazole, inhibitors of actin and tubulin filament formation respectively, strongly inhibited the recovery of green fluorescence at the plasma membrane suggestive for inhibition of KIR2.1 forward trafficking [τg,s 13 ± 2 vs. 131 ± 31* and 160 ± 40* min, for control, Cytochalasin B and Nocodazole, respectively (*p < 0.05 vs. control)]. Dyngo-4a, an inhibitor of dynamin motor proteins, strongly slowed the rate of photoconverted channel internalization, whereas Nocodazole and Cytochalasin B had less effect [τr,s 20 ± 2 vs. 87 ± 14*, 60 ± 16 and 64 ± 20 min (*p < 0.05 vs. control)]. Cytochalasin B treatment (20 μM, 24 h) inhibited IKIR2.1. Chloroquine treatment (10 μM, 24 h) induced intracellular aggregation of KIR2.1 channels and enhanced interaction with the actin/intermediate filament system (103 ± 90 fold; p < 0.05 vs. control). Functional actin and tubulin cytoskeleton systems are essential for forward trafficking of KIR2.1 channels, whereas initial backward trafficking relies on a functional dynamin system. Chronic disturbance of the actin system inhibits KIR2.1 currents. Internalized KIR2.1 channels become recruited to the cytoskeleton, presumably in lysosomes.
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Affiliation(s)
- Encan Li
- Department of Medical Physiology, Division of Heart & Lungs, University Medical Center Utrecht, Utrecht, Netherlands
| | - Vera Loen
- Department of Medical Physiology, Division of Heart & Lungs, University Medical Center Utrecht, Utrecht, Netherlands
| | - Willem B van Ham
- Department of Medical Physiology, Division of Heart & Lungs, University Medical Center Utrecht, Utrecht, Netherlands
| | - Willy Kool
- Department of Medical Physiology, Division of Heart & Lungs, University Medical Center Utrecht, Utrecht, Netherlands
| | - Marcel A G van der Heyden
- Department of Medical Physiology, Division of Heart & Lungs, University Medical Center Utrecht, Utrecht, Netherlands
| | - Hiroki Takanari
- Department of Interdisciplinary Researches for Medicine and Photonics, Institute of Post-LED Photonics, University of Tokushima, Tokushima, Japan
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Abstract
Microtubules are essential cytoskeletal elements found in all eukaryotic cells. The structure and composition of microtubules regulate their function, and the dynamic remodeling of the network by posttranslational modifications and microtubule-associated proteins generates diverse populations of microtubules adapted for various contexts. In the cardiomyocyte, the microtubules must accommodate the unique challenges faced by a highly contractile, rigidly structured, and long-lasting cell. Through their canonical trafficking role and positioning of mRNA, proteins, and organelles, microtubules regulate essential cardiomyocyte functions such as electrical activity, calcium handling, protein translation, and growth. In a more specialized role, posttranslationally modified microtubules form load-bearing structures that regulate myocyte mechanics and mechanotransduction. Modified microtubules proliferate in cardiovascular diseases, creating stabilized resistive elements that impede cardiomyocyte contractility and contribute to contractile dysfunction. In this review, we highlight the most exciting new concepts emerging from recent studies into canonical and noncanonical roles of cardiomyocyte microtubules.
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Affiliation(s)
- Keita Uchida
- Department of Physiology, Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA;
| | - Emily A Scarborough
- Department of Physiology, Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA;
| | - Benjamin L Prosser
- Department of Physiology, Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA;
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Sanyal C, Pietsch N, Ramirez Rios S, Peris L, Carrier L, Moutin MJ. The detyrosination/re-tyrosination cycle of tubulin and its role and dysfunction in neurons and cardiomyocytes. Semin Cell Dev Biol 2021; 137:46-62. [PMID: 34924330 DOI: 10.1016/j.semcdb.2021.12.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 12/07/2021] [Accepted: 12/08/2021] [Indexed: 12/28/2022]
Abstract
Among the variety of post-translational modifications to which microtubules are subjected, the detyrosination/re-tyrosination cycle is specific to tubulin. It is conserved by evolution and characterized by the enzymatic removal and re-addition of a gene-encoded tyrosine residue at the C-terminus of α-tubulin. Detyrosinated tubulin can be further converted to Δ2-tubulin by the removal of an additional C-terminal glutamate residue. Detyrosinated and Δ2-tubulin are carried by stable microtubules whereas tyrosinated microtubules are present on dynamic polymers. The cycle regulates trafficking of many cargo transporting molecular motors and is linked to the microtubule dynamics via regulation of microtubule interactions with specific cellular effectors such as kinesin-13. Here, we give an historical overview of the general features discovered for the cycle. We highlight the recent progress toward structure and functioning of the enzymes that keep the levels of tyrosinated and detyrosinated tubulin in cells, the long-known tubulin tyrosine ligase and the recently discovered vasohibin-SVBP complexes. We further describe how the cycle controls microtubule functions in healthy neurons and cardiomyocytes and how deregulations of the cycle are involved in dysfunctions of these highly differentiated cells, leading to neurodegeneration and heart failure in humans.
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Affiliation(s)
- Chadni Sanyal
- Univ. Grenoble Alpes, Inserm, U1216, CNRS, Grenoble Institut Neurosciences, 38000 Grenoble, France
| | - Niels Pietsch
- Institute of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany; DZHK (German Centre for Cardiovascular Research), partner site Hamburg/Kiel/Lübeck, Hamburg, Germany
| | - Sacnicte Ramirez Rios
- Univ. Grenoble Alpes, Inserm, U1216, CNRS, Grenoble Institut Neurosciences, 38000 Grenoble, France
| | - Leticia Peris
- Univ. Grenoble Alpes, Inserm, U1216, CNRS, Grenoble Institut Neurosciences, 38000 Grenoble, France
| | - Lucie Carrier
- Institute of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany; DZHK (German Centre for Cardiovascular Research), partner site Hamburg/Kiel/Lübeck, Hamburg, Germany.
| | - Marie-Jo Moutin
- Univ. Grenoble Alpes, Inserm, U1216, CNRS, Grenoble Institut Neurosciences, 38000 Grenoble, France.
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Marchal GA, Jouni M, Chiang DY, Pérez-Hernández M, Podliesna S, Yu N, Casini S, Potet F, Veerman CC, Klerk M, Lodder EM, Mengarelli I, Guan K, Vanoye CG, Rothenberg E, Charpentier F, Redon R, George AL, Verkerk AO, Bezzina CR, MacRae CA, Burridge PW, Delmar M, Galjart N, Portero V, Remme CA. Targeting the Microtubule EB1-CLASP2 Complex Modulates Na V1.5 at Intercalated Discs. Circ Res 2021; 129:349-365. [PMID: 34092082 PMCID: PMC8298292 DOI: 10.1161/circresaha.120.318643] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
[Figure: see text].
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Affiliation(s)
- Gerard A Marchal
- Department of Experimental Cardiology, Amsterdam UMC - location AMC, The Netherlands (G.A.M., S.P., S.C., C.C.V., E.M.L., I.M., A.O.V., C.R.B., V.P., C.A.R.)
| | - Mariam Jouni
- Department of Pharmacology, University Feinberg School of Medicine, Chicago, IL (M.J., F.P., C.G.V., A.L.G., P.W.B.)
| | - David Y Chiang
- Brigham and Women's Hospital and Harvard Medical School, Boston, MA (D.Y.C., C.A.M.)
| | | | - Svitlana Podliesna
- Department of Experimental Cardiology, Amsterdam UMC - location AMC, The Netherlands (G.A.M., S.P., S.C., C.C.V., E.M.L., I.M., A.O.V., C.R.B., V.P., C.A.R.)
| | - Nuo Yu
- Department of Cell Biology, Erasmus Medical Centre Rotterdam, The Netherlands (N.Y., N.G.)
| | - Simona Casini
- Department of Experimental Cardiology, Amsterdam UMC - location AMC, The Netherlands (G.A.M., S.P., S.C., C.C.V., E.M.L., I.M., A.O.V., C.R.B., V.P., C.A.R.)
| | - Franck Potet
- Department of Pharmacology, University Feinberg School of Medicine, Chicago, IL (M.J., F.P., C.G.V., A.L.G., P.W.B.)
| | - Christiaan C Veerman
- Department of Experimental Cardiology, Amsterdam UMC - location AMC, The Netherlands (G.A.M., S.P., S.C., C.C.V., E.M.L., I.M., A.O.V., C.R.B., V.P., C.A.R.)
| | - Mischa Klerk
- Department of Medical Biology, Amsterdam UMC - location AMC, The Netherlands (M.K., A.O.V.)
| | - Elisabeth M Lodder
- Department of Experimental Cardiology, Amsterdam UMC - location AMC, The Netherlands (G.A.M., S.P., S.C., C.C.V., E.M.L., I.M., A.O.V., C.R.B., V.P., C.A.R.)
| | - Isabella Mengarelli
- Department of Experimental Cardiology, Amsterdam UMC - location AMC, The Netherlands (G.A.M., S.P., S.C., C.C.V., E.M.L., I.M., A.O.V., C.R.B., V.P., C.A.R.)
| | - Kaomei Guan
- Institute of Pharmacology and Toxicology, Technische Universität Dresden, Germany (K.G.)
| | - Carlos G Vanoye
- Department of Pharmacology, University Feinberg School of Medicine, Chicago, IL (M.J., F.P., C.G.V., A.L.G., P.W.B.)
| | - Eli Rothenberg
- Department of Biochemistry and Pharmacology (E.R.), NYU School of Medicine
| | - Flavien Charpentier
- Université de Nantes, CNRS, INSERM, l'institut du Thorax, Nantes, France (F.C., R.R., V.P.)
| | - Richard Redon
- Université de Nantes, CNRS, INSERM, l'institut du Thorax, Nantes, France (F.C., R.R., V.P.)
| | - Alfred L George
- Department of Pharmacology, University Feinberg School of Medicine, Chicago, IL (M.J., F.P., C.G.V., A.L.G., P.W.B.)
| | - Arie O Verkerk
- Department of Experimental Cardiology, Amsterdam UMC - location AMC, The Netherlands (G.A.M., S.P., S.C., C.C.V., E.M.L., I.M., A.O.V., C.R.B., V.P., C.A.R.)
- Department of Medical Biology, Amsterdam UMC - location AMC, The Netherlands (M.K., A.O.V.)
| | - Connie R Bezzina
- Department of Experimental Cardiology, Amsterdam UMC - location AMC, The Netherlands (G.A.M., S.P., S.C., C.C.V., E.M.L., I.M., A.O.V., C.R.B., V.P., C.A.R.)
| | - Calum A MacRae
- Brigham and Women's Hospital and Harvard Medical School, Boston, MA (D.Y.C., C.A.M.)
| | - Paul W Burridge
- Department of Pharmacology, University Feinberg School of Medicine, Chicago, IL (M.J., F.P., C.G.V., A.L.G., P.W.B.)
| | - Mario Delmar
- Division of Cardiology (M.P.-H., M.D.), NYU School of Medicine
| | - Niels Galjart
- Department of Cell Biology, Erasmus Medical Centre Rotterdam, The Netherlands (N.Y., N.G.)
| | - Vincent Portero
- Department of Experimental Cardiology, Amsterdam UMC - location AMC, The Netherlands (G.A.M., S.P., S.C., C.C.V., E.M.L., I.M., A.O.V., C.R.B., V.P., C.A.R.)
- Université de Nantes, CNRS, INSERM, l'institut du Thorax, Nantes, France (F.C., R.R., V.P.)
| | - Carol Ann Remme
- Department of Experimental Cardiology, Amsterdam UMC - location AMC, The Netherlands (G.A.M., S.P., S.C., C.C.V., E.M.L., I.M., A.O.V., C.R.B., V.P., C.A.R.)
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Jepps TA. Kv7 channel trafficking by the microtubule network in vascular smooth muscle. Acta Physiol (Oxf) 2021; 232:e13692. [PMID: 34021973 PMCID: PMC8365713 DOI: 10.1111/apha.13692] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 05/17/2021] [Accepted: 05/19/2021] [Indexed: 12/17/2022]
Abstract
In arterial smooth muscle cells, changes in availability of integral membrane proteins influence the regulation of blood flow and blood pressure, which is critical for human health. However, the mechanisms that coordinate the trafficking and membrane expression of specific receptors and ion channels in vascular smooth muscle are poorly understood. In the vasculature, very little is known about microtubules, which form a road network upon which proteins can be transported to and from the cell membrane. This review article summarizes the impact of the microtubule network on arterial contractility, highlighting the importance of the network, with an emphasis on our recent findings regarding the trafficking of the voltage‐dependent Kv7 channels.
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Affiliation(s)
- Thomas A Jepps
- Vascular Biology Group Department of Biomedical Sciences University of Copenhagen Blegdamsvej 3 2200 Copenhagen N Denmark
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10
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van der Horst J, Rognant S, Abbott GW, Ozhathil LC, Hägglund P, Barrese V, Chuang CY, Jespersen T, Davies MJ, Greenwood IA, Gourdon P, Aalkjær C, Jepps TA. Dynein regulates Kv7.4 channel trafficking from the cell membrane. J Gen Physiol 2021; 153:211752. [PMID: 33533890 PMCID: PMC7863719 DOI: 10.1085/jgp.202012760] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2020] [Revised: 12/21/2020] [Accepted: 01/08/2021] [Indexed: 12/15/2022] Open
Abstract
The dynein motor protein transports proteins away from the cell membrane along the microtubule network. Recently, we found the microtubule network was important for regulating the membrane abundance of voltage-gated Kv7.4 potassium channels in vascular smooth muscle. Here, we aimed to investigate the influence of dynein on the microtubule-dependent internalization of the Kv7.4 channel. Patch-clamp recordings from HEK293B cells showed Kv7.4 currents were increased after inhibiting dynein function with ciliobrevin D or by coexpressing p50/dynamitin, which specifically interferes with dynein motor function. Mutation of a dynein-binding site in the Kv7.4 C terminus increased the Kv7.4 current and prevented p50 interference. Structured illumination microscopy, proximity ligation assays, and coimmunoprecipitation showed colocalization of Kv7.4 and dynein in mesenteric artery myocytes. Ciliobrevin D enhanced mesenteric artery relaxation to activators of Kv7.2–Kv7.5 channels and increased membrane abundance of Kv7.4 protein in isolated smooth muscle cells and HEK293B cells. Ciliobrevin D failed to enhance the negligible S-1–mediated relaxations after morpholino-mediated knockdown of Kv7.4. Mass spectrometry revealed an interaction of dynein with caveolin-1, confirmed using proximity ligation and coimmunoprecipitation assays, which also provided evidence for interaction of caveolin-1 with Kv7.4, confirming that Kv7.4 channels are localized to caveolae in mesenteric artery myocytes. Lastly, cholesterol depletion reduced the interaction of Kv7.4 with caveolin-1 and dynein while increasing the overall membrane expression of Kv7.4, although it attenuated the Kv7.4 current in oocytes and interfered with the action of ciliobrevin D and channel activators in arterial segments. Overall, this study shows that dynein can traffic Kv7.4 channels in vascular smooth muscle in a mechanism dependent on cholesterol-rich caveolae.
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Affiliation(s)
| | - Salomé Rognant
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Geoffrey W Abbott
- Bioelectricity Laboratory, Department of Physiology and Biophysics, School of Medicine, University of California, Irvine, CA
| | | | - Per Hägglund
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Vincenzo Barrese
- St. George's, University of London, London, UK.,Department of Neuroscience, Reproductive Science and Dentistry, University of Naples "Federico II," Naples, Italy
| | - Christine Y Chuang
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Thomas Jespersen
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Michael J Davies
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | | | - Pontus Gourdon
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark.,Department of Medical Sciences, Lund University, Lund, Sweden
| | - Christian Aalkjær
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark.,Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Thomas A Jepps
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
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11
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Melgari D, Barbier C, Dilanian G, Rücker-Martin C, Doisne N, Coulombe A, Hatem SN, Balse E. Microtubule polymerization state and clathrin-dependent internalization regulate dynamics of cardiac potassium channel: Microtubule and clathrin control of K V1.5 channel. J Mol Cell Cardiol 2020; 144:127-139. [PMID: 32445844 DOI: 10.1016/j.yjmcc.2020.05.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 05/08/2020] [Accepted: 05/09/2020] [Indexed: 12/19/2022]
Abstract
Ion channel trafficking powerfully influences cardiac electrical activity as it regulates the number of available channels at the plasma membrane. Studies have largely focused on identifying the molecular determinants of the trafficking of the atria-specific KV1.5 channel, the molecular basis of the ultra-rapid delayed rectifier current IKur. Besides, regulated KV1.5 channel recycling upon changes in homeostatic state and mechanical constraints in native cardiomyocytes has been well documented. Here, using cutting-edge imaging in live myocytes, we investigated the dynamics of this channel in the plasma membrane. We demonstrate that the clathrin pathway is a major regulator of the functional expression of KV1.5 channels in atrial myocytes, with the microtubule network as the prominent organizer of KV1.5 transport within the membrane. Both clathrin blockade and microtubule disruption result in channel clusterization with reduced membrane mobility and internalization, whereas disassembly of the actin cytoskeleton does not. Mobile KV1.5 channels are associated with the microtubule plus-end tracking protein EB1 whereas static KV1.5 clusters are associated with stable acetylated microtubules. In human biopsies from patients in atrial fibrillation associated with atrial remodeling, drastic modifications in the trafficking balance occurs together with alteration in microtubule polymerization state resulting in modest reduced endocytosis and increased recycling. Consequently, hallmark of atrial KV1.5 dynamics within the membrane is clathrin- and microtubule- dependent. During atrial remodeling, predominance of anterograde trafficking activity over retrograde trafficking could result in accumulation ok KV1.5 channels in the plasma membrane.
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Affiliation(s)
- Dario Melgari
- INSERM UMRS1166, ICAN - Institute of CardioMetabolism and Nutrition, Sorbonne Université, Paris, France
| | - Camille Barbier
- INSERM UMRS1166, ICAN - Institute of CardioMetabolism and Nutrition, Sorbonne Université, Paris, France
| | - Gilles Dilanian
- INSERM UMRS1166, ICAN - Institute of CardioMetabolism and Nutrition, Sorbonne Université, Paris, France
| | | | - Nicolas Doisne
- INSERM UMRS1166, ICAN - Institute of CardioMetabolism and Nutrition, Sorbonne Université, Paris, France
| | - Alain Coulombe
- INSERM UMRS1166, ICAN - Institute of CardioMetabolism and Nutrition, Sorbonne Université, Paris, France
| | - Stéphane N Hatem
- INSERM UMRS1166, ICAN - Institute of CardioMetabolism and Nutrition, Sorbonne Université, Paris, France; Institut de Cardiologie, Hôpital Pitié-Salpêtrière, Paris, France
| | - Elise Balse
- INSERM UMRS1166, ICAN - Institute of CardioMetabolism and Nutrition, Sorbonne Université, Paris, France.
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12
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Sengupta S, Rothenberg KE, Li H, Hoffman BD, Bursac N. Altering integrin engagement regulates membrane localization of K ir2.1 channels. J Cell Sci 2019; 132:jcs225383. [PMID: 31391240 PMCID: PMC6771140 DOI: 10.1242/jcs.225383] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Accepted: 07/31/2019] [Indexed: 12/26/2022] Open
Abstract
How ion channels localize and distribute on the cell membrane remains incompletely understood. We show that interventions that vary cell adhesion proteins and cell size also affect the membrane current density of inward-rectifier K+ channels (Kir2.1; encoded by KCNJ2) and profoundly alter the action potential shape of excitable cells. By using micropatterning to manipulate the localization and size of focal adhesions (FAs) in single HEK293 cells engineered to stably express Kir2.1 channels or in neonatal rat cardiomyocytes, we establish a robust linear correlation between FA coverage and the amplitude of Kir2.1 current at both the local and whole-cell levels. Confocal microscopy showed that Kir2.1 channels accumulate in membrane proximal to FAs. Selective pharmacological inhibition of key mediators of protein trafficking and the spatially dependent alterations in the dynamics of Kir2.1 fluorescent recovery after photobleaching revealed that the Kir2.1 channels are transported to the cell membrane uniformly, but are preferentially internalized by endocytosis at sites that are distal from FAs. Based on these results, we propose adhesion-regulated membrane localization of ion channels as a fundamental mechanism of controlling cellular electrophysiology via mechanochemical signals, independent of the direct ion channel mechanogating.
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Affiliation(s)
- Swarnali Sengupta
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA
| | | | - Hanjun Li
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA
| | - Brenton D Hoffman
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA
| | - Nenad Bursac
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA
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13
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Caporizzo MA, Chen CY, Prosser BL. Cardiac microtubules in health and heart disease. Exp Biol Med (Maywood) 2019; 244:1255-1272. [PMID: 31398994 DOI: 10.1177/1535370219868960] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Cardiomyocytes are large (∼40,000 µm3), rod-shaped muscle cells that provide the working force behind each heartbeat. These highly structured cells are packed with dense cytoskeletal networks that can be divided into two groups—the contractile (i.e. sarcomeric) cytoskeleton that consists of filamentous actin-myosin arrays organized into myofibrils, and the non-sarcomeric cytoskeleton, which is composed of β- and γ-actin, microtubules, and intermediate filaments. Together, microtubules and intermediate filaments form a cross-linked scaffold, and these networks are responsible for the delivery of intracellular cargo, the transmission of mechanical signals, the shaping of membrane systems, and the organization of myofibrils and organelles. Microtubules are extensively altered as part of both adaptive and pathological cardiac remodeling, which has diverse ramifications for the structure and function of the cardiomyocyte. In heart failure, the proliferation and post-translational modification of the microtubule network is linked to a number of maladaptive processes, including the mechanical impediment of cardiomyocyte contraction and relaxation. This raises the possibility that reversing microtubule alterations could improve cardiac performance, yet therapeutic efforts will strongly benefit from a deeper understanding of basic microtubule biology in the heart. The aim of this review is to summarize the known physiological roles of the cardiomyocyte microtubule network, the consequences of its pathological remodeling, and to highlight the open and intriguing questions regarding cardiac microtubules. Impact statement Advancements in cell biological and biophysical approaches and super-resolution imaging have greatly broadened our view of tubulin biology over the last decade. In the heart, microtubules and microtubule-based transport help to organize and maintain key structures within the cardiomyocyte, including the sarcomere, intercalated disc, protein clearance machinery and transverse-tubule and sarcoplasmic reticulum membranes. It has become increasingly clear that post translational regulation of microtubules is a key determinant of their sub-cellular functionality. Alterations in microtubule network density, stability, and post-translational modifications are hallmarks of pathological cardiac remodeling, and modified microtubules can directly impede cardiomyocyte contractile function in various forms of heart disease. This review summarizes the functional roles and multi-leveled regulation of the cardiac microtubule cytoskeleton and highlights how refined experimental techniques are shedding mechanistic clarity on the regionally specified roles of microtubules in cardiac physiology and pathophysiology.
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Affiliation(s)
- Matthew A Caporizzo
- Department of Physiology, Pennsylvania Muscle Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Christina Yingxian Chen
- Department of Physiology, Pennsylvania Muscle Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Benjamin L Prosser
- Department of Physiology, Pennsylvania Muscle Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA.,Penn Cardiovascular Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
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14
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Grimes KM, Prasad V, McNamara JW. Supporting the heart: Functions of the cardiomyocyte's non-sarcomeric cytoskeleton. J Mol Cell Cardiol 2019; 131:187-196. [PMID: 30978342 DOI: 10.1016/j.yjmcc.2019.04.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/02/2018] [Revised: 04/02/2019] [Accepted: 04/05/2019] [Indexed: 02/06/2023]
Abstract
The non-contractile cytoskeleton in cardiomyocytes is comprised of cytoplasmic actin, microtubules, and intermediate filaments. In addition to providing mechanical support to these cells, these structures are important effectors of tension-sensing and signal transduction and also provide networks for the transport of proteins and organelles. The majority of our knowledge on the function and structure of these cytoskeletal networks comes from research on proliferative cell types. However, in recent years, researchers have begun to show that there are important cardiomyocyte-specific functions of the cytoskeleton. Here we will discuss the current state of cytoskeletal biology in cardiomyocytes, as well as research from other cell types, that together suggest there is a wealth of knowledge on cardiac health and disease waiting to be uncovered through exploration of the complex signaling networks of cardiomyocyte non-sarcomeric cytoskeletal proteins.
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Affiliation(s)
- Kelly M Grimes
- Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA.
| | - Vikram Prasad
- Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - James W McNamara
- Heart, Lung and Vascular Institute, University of Cincinnati, Cincinnati, OH, USA
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15
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Drum BML, Yuan C, Li L, Liu Q, Wordeman L, Santana LF. Oxidative stress decreases microtubule growth and stability in ventricular myocytes. J Mol Cell Cardiol 2016; 93:32-43. [PMID: 26902968 PMCID: PMC4902331 DOI: 10.1016/j.yjmcc.2016.02.012] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Revised: 01/21/2016] [Accepted: 02/12/2016] [Indexed: 02/05/2023]
Abstract
Microtubules (MTs) have many roles in ventricular myocytes, including structural stability, morphological integrity, and protein trafficking. However, despite their functional importance, dynamic MTs had never been visualized in living adult myocytes. Using adeno-associated viral vectors expressing the MT-associated protein plus end binding protein 3 (EB3) tagged with EGFP, we were able to perform live imaging and thus capture and quantify MT dynamics in ventricular myocytes in real time under physiological conditions. Super-resolution nanoscopy revealed that EB1 associated in puncta along the length of MTs in ventricular myocytes. The vast (~80%) majority of MTs grew perpendicular to T-tubules at a rate of 0.06μm∗s(-1) and growth was preferentially (82%) confined to a single sarcomere. Microtubule catastrophe rate was lower near the Z-line than M-line. Hydrogen peroxide increased the rate of catastrophe of MTs ~7-fold, suggesting that oxidative stress destabilizes these structures in ventricular myocytes. We also quantified MT dynamics after myocardial infarction (MI), a pathological condition associated with increased production of reactive oxygen species (ROS). Our data indicate that the catastrophe rate of MTs increases following MI. This contributed to decreased transient outward K(+) currents by decreasing the surface expression of Kv4.2 and Kv4.3 channels after MI. On the basis of these data, we conclude that, under physiological conditions, MT growth is directionally biased and that increased ROS production during MI disrupts MT dynamics, decreasing K(+) channel trafficking.
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Affiliation(s)
- Benjamin M L Drum
- Department of Physiology & Biophysics, University of Washington School of Medicine, Seattle, WA 98195, United States
| | - Can Yuan
- Department of Physiology & Biophysics, University of Washington School of Medicine, Seattle, WA 98195, United States
| | - Lei Li
- Department of Physiology & Biophysics, University of Washington School of Medicine, Seattle, WA 98195, United States
| | - Qinghang Liu
- Department of Physiology & Biophysics, University of Washington School of Medicine, Seattle, WA 98195, United States
| | - Linda Wordeman
- Department of Physiology & Biophysics, University of Washington School of Medicine, Seattle, WA 98195, United States
| | - L Fernando Santana
- Deparment of Physiology & Membrane Biology, University of California School of Medicine, Davis, CA 95616, United States.
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16
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Abstract
The major cardiac voltage-gated sodium channel Nav1.5 associates with proteins that regulate its biosynthesis, localization, activity and degradation. Identification of partner proteins is crucial for a better understanding of the channel regulation. Using a yeast two-hybrid screen, we identified dynamitin as a Nav1.5-interacting protein. Dynamitin is part of the microtubule-binding multiprotein complex dynactin. When overexpressed it is a potent inhibitor of dynein/kinesin-mediated transport along the microtubules by disrupting the dynactin complex and dissociating cargoes from microtubules. The use of deletion constructs showed that the C-terminal domain of dynamitin is essential for binding to the first intracellular interdomain of Nav1.5. Co-immunoprecipitation assays confirmed the association between Nav1.5 and dynamitin in mouse heart extracts. Immunostaining experiments showed that dynamitin and Nav1.5 co-localize at intercalated discs of mouse cardiomyocytes. The whole-cell patch-clamp technique was applied to test the functional link between Nav1.5 and dynamitin. Dynamitin overexpression in HEK-293 (human embryonic kidney 293) cells expressing Nav1.5 resulted in a decrease in sodium current density in the membrane with no modification of the channel-gating properties. Biotinylation experiments produced similar information with a reduction in Nav1.5 at the cell surface when dynactin-dependent transport was inhibited. The present study strongly suggests that dynamitin is involved in the regulation of Nav1.5 cell-surface density.
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17
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Chen SR, Zhu L, Chen H, Wen L, Laumet G, Pan HL. Increased spinal cord Na⁺-K⁺-2Cl⁻ cotransporter-1 (NKCC1) activity contributes to impairment of synaptic inhibition in paclitaxel-induced neuropathic pain. J Biol Chem 2014; 289:31111-20. [PMID: 25253692 DOI: 10.1074/jbc.m114.600320] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Microtubule-stabilizing agents, such as paclitaxel (Taxol), are effective chemotherapy drugs for treating many cancers, and painful neuropathy is a major dose-limiting adverse effect. Cation-chloride cotransporters, such as Na(+)-K(+)-2Cl(-) cotransporter-1 (NKCC1) and K(+)-Cl(-) cotransporter-2 (KCC2), critically influence spinal synaptic inhibition by regulating intracellular chloride concentrations. Here we show that paclitaxel treatment in rats significantly reduced GABA-induced membrane hyperpolarization and caused a depolarizing shift in GABA reversal potential of dorsal horn neurons. However, paclitaxel had no significant effect on AMPA or NMDA receptor-mediated glutamatergic input from primary afferents to dorsal horn neurons. Paclitaxel treatment significantly increased protein levels, but not mRNA levels, of NKCC1 in spinal cords. Inhibition of NKCC1 with bumetanide reversed the paclitaxel effect on GABA-mediated hyperpolarization and GABA reversal potentials. Also, intrathecal bumetanide significantly attenuated hyperalgesia and allodynia induced by paclitaxel. Co-immunoprecipitation revealed that NKCC1 interacted with β-tubulin and β-actin in spinal cords. Remarkably, paclitaxel increased NKCC1 protein levels at the plasma membrane and reduced NKCC1 levels in the cytosol of spinal cords. In contrast, treatment with an actin-stabilizing agent had no significant effect on NKCC1 protein levels in the plasma membrane or cytosolic fractions of spinal cords. In addition, inhibition of the motor protein dynein blocked paclitaxel-induced subcellular redistribution of NKCC1, whereas inhibition of kinesin-5 mimicked the paclitaxel effect. Our findings suggest that increased NKCC1 activity contributes to diminished spinal synaptic inhibition and neuropathic pain caused by paclitaxel. Paclitaxel disrupts intracellular NKCC1 trafficking by interfering with microtubule dynamics and associated motor proteins.
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Affiliation(s)
- Shao-Rui Chen
- From the Center for Neuroscience and Pain Research, Department of Anesthesiology and Perioperative Medicine, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030
| | - Lihong Zhu
- From the Center for Neuroscience and Pain Research, Department of Anesthesiology and Perioperative Medicine, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030
| | - Hong Chen
- From the Center for Neuroscience and Pain Research, Department of Anesthesiology and Perioperative Medicine, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030
| | - Lei Wen
- From the Center for Neuroscience and Pain Research, Department of Anesthesiology and Perioperative Medicine, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030
| | - Geoffroy Laumet
- From the Center for Neuroscience and Pain Research, Department of Anesthesiology and Perioperative Medicine, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030
| | - Hui-Lin Pan
- From the Center for Neuroscience and Pain Research, Department of Anesthesiology and Perioperative Medicine, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030
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18
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Schumacher-Bass SM, Vesely ED, Zhang L, Ryland KE, McEwen DP, Chan PJ, Frasier CR, McIntyre JC, Shaw RM, Martens JR. Role for myosin-V motor proteins in the selective delivery of Kv channel isoforms to the membrane surface of cardiac myocytes. Circ Res 2014; 114:982-92. [PMID: 24508725 DOI: 10.1161/circresaha.114.302711] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
RATIONALE Kv1.5 (KCNA5) mediates the ultra-rapid delayed rectifier current that controls atrial action potential duration. Given its atrial-specific expression and alterations in human atrial fibrillation, Kv1.5 has emerged as a promising target for the treatment of atrial fibrillation. A necessary step in the development of novel agents that selectively modulate trafficking pathways is the identification of the cellular machinery controlling Kv1.5 surface density, of which little is yet known. OBJECTIVE To investigate the role of the unconventional myosin-V (MYO5A and MYO5B) motors in determining the cell surface density of Kv1.5. METHODS AND RESULTS Western blot analysis showed MYO5A and MYO5B expression in the heart, whereas disruption of endogenous motors selectively reduced IKur current in adult rat cardiomyocytes. Dominant negative constructs and short hairpin RNA silencing demonstrated a role for MYO5A and MYO5B in the surface trafficking of Kv1.5 and connexin-43 but not potassium voltage-gated channel, subfamily H (eag-related), member 2 (KCNH2). Live-cell imaging of Kv1.5-GFP and retrospective labeling of phalloidin demonstrated motility of Kv1.5 vesicles on actin tracts. MYO5A participated in anterograde trafficking, whereas MYO5B regulated postendocytic recycling. Overexpression of mutant motors revealed a selective role for Rab11 in coupling MYO5B to Kv1.5 recycling. CONCLUSIONS MYO5A and MYO5B control functionally distinct steps in the surface trafficking of Kv1.5. These isoform-specific trafficking pathways determine Kv1.5-encoded IKur in myocytes to regulate repolarizing current and, consequently, cardiac excitability. Therapeutic strategies that manipulate Kv1.5 selective trafficking pathways may prove useful in the treatment of arrhythmias.
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Affiliation(s)
- Sarah M Schumacher-Bass
- From the Department of Pharmacology, University of Michigan, Ann Arbor (S.M.S.-B., E.D.V., L.Z., K.E.R., D.P.M., C.R.F., J.C.M., J.R.M.); Cardiovascular Research Institute Robin Shaw, Department of Medicine, University of California, San Francisco (P.J.C.); and Cedars-Sinai Medical Center, Los Angeles, CA (R.M.S.)
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19
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Shear stress triggers insertion of voltage-gated potassium channels from intracellular compartments in atrial myocytes. Proc Natl Acad Sci U S A 2013; 110:E3955-64. [PMID: 24065831 DOI: 10.1073/pnas.1309896110] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Atrial myocytes are continuously exposed to mechanical forces including shear stress. However, in atrial myocytes, the effects of shear stress are poorly understood, particularly with respect to its effect on ion channel function. Here, we report that shear stress activated a large outward current from rat atrial myocytes, with a parallel decrease in action potential duration. The main ion channel underlying the increase in current was found to be Kv1.5, the recruitment of which could be directly observed by total internal reflection fluorescence microscopy, in response to shear stress. The effect was primarily attributable to recruitment of intracellular pools of Kv1.5 to the sarcolemma, as the response was prevented by the SNARE protein inhibitor N-ethylmaleimide and the calcium chelator BAPTA. The process required integrin signaling through focal adhesion kinase and relied on an intact microtubule system. Furthermore, in a rat model of chronic hemodynamic overload, myocytes showed an increase in basal current despite a decrease in Kv1.5 protein expression, with a reduced response to shear stress. Additionally, integrin beta1d expression and focal adhesion kinase activation were increased in this model. This data suggests that, under conditions of chronically increased mechanical stress, the integrin signaling pathway is overactivated, leading to increased functional Kv1.5 at the membrane and reducing the capacity of cells to further respond to mechanical challenge. Thus, pools of Kv1.5 may comprise an inducible reservoir that can facilitate the repolarization of the atrium under conditions of excessive mechanical stress.
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20
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Steele DF, Fedida D. Cytoskeletal roles in cardiac ion channel expression. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2013; 1838:665-73. [PMID: 23680626 DOI: 10.1016/j.bbamem.2013.05.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2013] [Revised: 05/01/2013] [Accepted: 05/06/2013] [Indexed: 11/25/2022]
Abstract
The cytoskeleton and cardiac ion channel expression are closely linked. From the time that newly synthesized channels exit the endoplasmic reticulum, they are either traveling along the microtubule or actin cytoskeletons or likely anchored in the plasma membrane or in internal vesicular pools by those scaffolds. Molecular motors, small GTPases and even the dynamics of the cytoskeletons themselves influence the trafficking and expression of the channels. In some cases, the functioning of the channels themselves has profound influences on the cytoskeleton. Here we provide an overview of the current state of knowledge on the involvement of the actin and microtubule cytoskeletons in the trafficking, targeting and expression of cardiac ion channels and a few channels expressed elsewhere. We highlight, also, some of the many questions that remain about these processes. This article is part of a Special Issue entitled: Reciprocal influences between cell cytoskeleton and membrane channels, receptors and transporters. Guest Editor: Jean Claude Hervé.
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Affiliation(s)
- David F Steele
- Dept. of Anesthesiology, Pharmacology and Therapeutics, University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada
| | - David Fedida
- Dept. of Anesthesiology, Pharmacology and Therapeutics, University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada.
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21
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Goldoni D, Yarham J, McGahon M, O’Connor A, Guduric-Fuchs J, Edgar K, McDonald D, Simpson D, Collins A. A novel dual-fluorescence strategy for functionally validating microRNA targets in 3' untranslated regions: regulation of the inward rectifier potassium channel K(ir)2.1 by miR-212. Biochem J 2012; 448:103-13. [PMID: 22880819 PMCID: PMC3475433 DOI: 10.1042/bj20120578] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2012] [Revised: 08/03/2012] [Accepted: 08/13/2012] [Indexed: 01/16/2023]
Abstract
Gene targeting by microRNAs is important in health and disease. We developed a functional assay for identifying microRNA targets and applied it to the K(+) channel K(ir)2.1 [KCNJ2 (potassium inwardly-rectifying channel, subfamily J, member 2)] which is dysregulated in cardiac and vascular disorders. The 3'UTR (untranslated region) was inserted downstream of the mCherry red fluorescent protein coding sequence in a mammalian expression plasmid. MicroRNA sequences were inserted into the pSM30 expression vector which provides enhanced green fluorescent protein as an indicator of microRNA expression. HEK (human embryonic kidney)-293 cells were co-transfected with the mCherry-3'UTR plasmid and a pSM30-based plasmid with a microRNA insert. The principle of the assay is that functional targeting of the 3'UTR by the microRNA results in a decrease in the red/green fluorescence intensity ratio as determined by automated image analysis. The method was validated with miR-1, a known down-regulator of K(ir)2.1 expression, and was used to investigate the targeting of the K(ir)2.1 3'UTR by miR-212. The red/green ratio was lower in miR-212-expressing cells compared with the non-targeting controls, an effect that was attenuated by mutating the predicted target site. miR-212 also reduced inward rectifier current and K(ir)2.1 protein in HeLa cells. This novel assay has several advantages over traditional luciferase-based assays including larger sample size, amenability to time course studies and adaptability to high-throughput screening.
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Key Words
- hela cell
- hek-293 cell
- image analysis
- microrna
- patch clamp
- cmv, cytomegalovirus
- dmem, dulbecco’s modified eagle’s medium
- egfp, enhanced green fluorescent protein
- gapdh, glyceraldehyde-3-phosphate dehydrogenase
- hek, human embryonic kidney
- hprt1, hypoxanthine–phosphoribosyltransferase 1
- ik1, inward-rectifier k+ current
- kcnj2, potassium inwardly-rectifying channel, subfamily j, member 2
- mirna, microrna
- qrt–pcr, quantitative reverse transcription pcr
- race, rapid amplification of cdna ends
- sirna, short interfering rna
- utr, untranslated region
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Affiliation(s)
- Dana Goldoni
- Centre for Vision and Vascular Science, Queen's University of Belfast, Institute of Clinical Science, Block A, Royal Victoria Hospital, Grosvenor Road, Belfast, BT12 6BA, U.K
| | - Janet M. Yarham
- Centre for Vision and Vascular Science, Queen's University of Belfast, Institute of Clinical Science, Block A, Royal Victoria Hospital, Grosvenor Road, Belfast, BT12 6BA, U.K
| | - Mary K. McGahon
- Centre for Vision and Vascular Science, Queen's University of Belfast, Institute of Clinical Science, Block A, Royal Victoria Hospital, Grosvenor Road, Belfast, BT12 6BA, U.K
| | - Anna O’Connor
- Centre for Vision and Vascular Science, Queen's University of Belfast, Institute of Clinical Science, Block A, Royal Victoria Hospital, Grosvenor Road, Belfast, BT12 6BA, U.K
| | - Jasenka Guduric-Fuchs
- Centre for Vision and Vascular Science, Queen's University of Belfast, Institute of Clinical Science, Block A, Royal Victoria Hospital, Grosvenor Road, Belfast, BT12 6BA, U.K
| | - Kevin Edgar
- Centre for Vision and Vascular Science, Queen's University of Belfast, Institute of Clinical Science, Block A, Royal Victoria Hospital, Grosvenor Road, Belfast, BT12 6BA, U.K
| | - Denise M. McDonald
- Centre for Vision and Vascular Science, Queen's University of Belfast, Institute of Clinical Science, Block A, Royal Victoria Hospital, Grosvenor Road, Belfast, BT12 6BA, U.K
| | - David A. Simpson
- Centre for Vision and Vascular Science, Queen's University of Belfast, Institute of Clinical Science, Block A, Royal Victoria Hospital, Grosvenor Road, Belfast, BT12 6BA, U.K
| | - Anthony Collins
- Centre for Vision and Vascular Science, Queen's University of Belfast, Institute of Clinical Science, Block A, Royal Victoria Hospital, Grosvenor Road, Belfast, BT12 6BA, U.K
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Wang T, Cheng Y, Dou Y, Goonesekara C, David JP, Steele DF, Huang C, Fedida D. Trafficking of an endogenous potassium channel in adult ventricular myocytes. Am J Physiol Cell Physiol 2012; 303:C963-76. [PMID: 22914645 DOI: 10.1152/ajpcell.00217.2012] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The roles of several small GTPases in the expression of an endogenous potassium current, I(to,f), in adult rat ventricular myocytes have been investigated. The results indicate that forward trafficking of newly synthesized Kv4.2, which underlies I(to,f) in these cells, requires both Rab1 and Sar1 function. Expression of a Rab1 dominant negative (DN) reduced I(to,f) current density by roughly one-half relative to control, mCherry-transfected myocytes. Similarly, expression of a Sar1DN nearly halved I(to,f) current density. Rab11 is not essential to trafficking of Kv4.2, as expression of a Rab11DN had no effect on I(to,f) over the time frames investigated here. In a process dependent on intact endoplasmic reticulum (ER)-to-Golgi transport, however, overexpression of wild-type Rab11 resulted in a doubling of I(to,f) density; block of ER-to-Golgi traffic by Brefeldin A completely abrogated the effect. Also implicated in the trafficking of Kv4.2 are Rab5 and Rab4. Rab5DN expression increased endogenous I(to,f) by two- to threefold, nonadditively with inhibition of dynamin-dependent endocytosis. And, in a phenomenon similar to that previously reported for myoblast-expressed Kv1.5, Rab4DN expression roughly doubled endogenous peak transient currents. Colocalization experiments confirmed the involvement of Rab4 in postinternalization trafficking of Kv4.2. There was little role evident for the lysosome in the degradation of internalized Kv4.2, as overexpression of neither wild-type nor DN isoforms of Rab7 had any effect on I(to,f). Instead, degradation may depend largely on the proteasome; the proteasome inhibitor MG132 significantly increased I(to,f) density.
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Affiliation(s)
- Tiantian Wang
- Dept. of Anesthesiology, Pharmacology and Therapeutics, Univ. of British Columbia, 2350 Health Sciences Mall, Vancouver, BC, Canada V6T 1Z3.
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23
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Özgen N, Lu Z, Boink GJJ, Lau DH, Shlapakova IN, Bobkov Y, Danilo P, Cohen IS, Rosen MR. Microtubules and angiotensin II receptors contribute to modulation of repolarization induced by ventricular pacing. Heart Rhythm 2012; 9:1865-72. [PMID: 22820054 DOI: 10.1016/j.hrthm.2012.07.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/04/2012] [Indexed: 01/09/2023]
Abstract
BACKGROUND Left ventricular pacing (LVP) in canine heart alters ventricular activation, leading to reduced transient outward potassium current (I(to)), loss of the epicardial action potential notch, and T-wave vector displacement. These repolarization changes, referred to as cardiac memory, are initiated by locally increased angiotensin II (AngII) levels. In HEK293 cells in which Kv4.3 and KChIP2, the channel subunits contributing to I(to), are overexpressed with the AngII receptor 1 (AT1R), AngII induces a decrease in I(to) as the result of internalization of a Kv4.3/KChIP2/AT1R macromolecular complex. OBJECTIVE To test the hypothesis that in canine heart in situ, 2h LVP-induced decreases in membrane KChIP2, AT1R, and I(to) are prevented by blocking subunit trafficking. METHODS We used standard electrophysiological, biophysical, and biochemical methods to study 4 groups of dogs: (1) Sham, (2) 2h LVP, (3) LVP + colchicine (microtubule-disrupting agent), and (4) LVP + losartan (AT1R blocker). RESULTS The T-wave vector displacement was significantly greater in LVP than in Sham and was inhibited by colchicine or losartan. Epicardial biopsies showed significant decreases in KChIP2 and AT1R proteins in the membrane fraction after LVP but not after sham treatment, and these decreases were prevented by colchicine or losartan. Colchicine but not losartan significantly reduced microtubular polymerization. In isolated ventricular myocytes, AngII-induced I(to) reduction and loss of action potential notch were blocked by colchicine. CONCLUSIONS LVP-induced reduction of KChIP2 in plasma light membranes depends on an AngII-mediated pathway and intact microtubular status. Loss of I(to) and the action potential notch appear to derive from AngII-initiated trafficking of channel subunits.
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Affiliation(s)
- Nazira Özgen
- Department of Pharmacology, Columbia University, New York, New York 10032, USA
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24
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Balse E, Steele DF, Abriel H, Coulombe A, Fedida D, Hatem SN. Dynamic of Ion Channel Expression at the Plasma Membrane of Cardiomyocytes. Physiol Rev 2012; 92:1317-58. [DOI: 10.1152/physrev.00041.2011] [Citation(s) in RCA: 90] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Cardiac myocytes are characterized by distinct structural and functional entities involved in the generation and transmission of the action potential and the excitation-contraction coupling process. Key to their function is the specific organization of ion channels and transporters to and within distinct membrane domains, which supports the anisotropic propagation of the depolarization wave. This review addresses the current knowledge on the molecular actors regulating the distinct trafficking and targeting mechanisms of ion channels in the highly polarized cardiac myocyte. In addition to ubiquitous mechanisms shared by other excitable cells, cardiac myocytes show unique specialization, illustrated by the molecular organization of myocyte-myocyte contacts, e.g., the intercalated disc and the gap junction. Many factors contribute to the specialization of the cardiac sarcolemma and the functional expression of cardiac ion channels, including various anchoring proteins, motors, small GTPases, membrane lipids, and cholesterol. The discovery of genetic defects in some of these actors, leading to complex cardiac disorders, emphasizes the importance of trafficking and targeting of ion channels to cardiac function. A major challenge in the field is to understand how these and other actors work together in intact myocytes to fine-tune ion channel expression and control cardiac excitability.
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Affiliation(s)
- Elise Balse
- Institute of Cardiometabolism and Nutrition, Paris, France; Assistance Publique-Hôpitaux de Paris, Pitié-Salpêtrière Hospital, Heart and Metabolism Division, Paris, France; Institut National de la Santé et de la Recherche Médicale UMR_S956, Paris, France; Université Pierre et Marie Curie, Paris, France; Department of Anesthesiology, Pharmacology, and Therapeutics, University of British Columbia, Vancouver, Canada; and Department of Clinical Research University of Bern, Bern, Switzerland
| | - David F. Steele
- Institute of Cardiometabolism and Nutrition, Paris, France; Assistance Publique-Hôpitaux de Paris, Pitié-Salpêtrière Hospital, Heart and Metabolism Division, Paris, France; Institut National de la Santé et de la Recherche Médicale UMR_S956, Paris, France; Université Pierre et Marie Curie, Paris, France; Department of Anesthesiology, Pharmacology, and Therapeutics, University of British Columbia, Vancouver, Canada; and Department of Clinical Research University of Bern, Bern, Switzerland
| | - Hugues Abriel
- Institute of Cardiometabolism and Nutrition, Paris, France; Assistance Publique-Hôpitaux de Paris, Pitié-Salpêtrière Hospital, Heart and Metabolism Division, Paris, France; Institut National de la Santé et de la Recherche Médicale UMR_S956, Paris, France; Université Pierre et Marie Curie, Paris, France; Department of Anesthesiology, Pharmacology, and Therapeutics, University of British Columbia, Vancouver, Canada; and Department of Clinical Research University of Bern, Bern, Switzerland
| | - Alain Coulombe
- Institute of Cardiometabolism and Nutrition, Paris, France; Assistance Publique-Hôpitaux de Paris, Pitié-Salpêtrière Hospital, Heart and Metabolism Division, Paris, France; Institut National de la Santé et de la Recherche Médicale UMR_S956, Paris, France; Université Pierre et Marie Curie, Paris, France; Department of Anesthesiology, Pharmacology, and Therapeutics, University of British Columbia, Vancouver, Canada; and Department of Clinical Research University of Bern, Bern, Switzerland
| | - David Fedida
- Institute of Cardiometabolism and Nutrition, Paris, France; Assistance Publique-Hôpitaux de Paris, Pitié-Salpêtrière Hospital, Heart and Metabolism Division, Paris, France; Institut National de la Santé et de la Recherche Médicale UMR_S956, Paris, France; Université Pierre et Marie Curie, Paris, France; Department of Anesthesiology, Pharmacology, and Therapeutics, University of British Columbia, Vancouver, Canada; and Department of Clinical Research University of Bern, Bern, Switzerland
| | - Stéphane N. Hatem
- Institute of Cardiometabolism and Nutrition, Paris, France; Assistance Publique-Hôpitaux de Paris, Pitié-Salpêtrière Hospital, Heart and Metabolism Division, Paris, France; Institut National de la Santé et de la Recherche Médicale UMR_S956, Paris, France; Université Pierre et Marie Curie, Paris, France; Department of Anesthesiology, Pharmacology, and Therapeutics, University of British Columbia, Vancouver, Canada; and Department of Clinical Research University of Bern, Bern, Switzerland
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25
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Dynamic changes in sarcoplasmic reticulum structure in ventricular myocytes. J Biomed Biotechnol 2011; 2011:382586. [PMID: 22131804 PMCID: PMC3206393 DOI: 10.1155/2011/382586] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2011] [Accepted: 08/09/2011] [Indexed: 11/23/2022] Open
Abstract
The fidelity of excitation-contraction (EC) coupling in ventricular myocytes is remarkable, with each action potential evoking a [Ca2+]i transient. The prevalent model is that the consistency in EC coupling in ventricular myocytes is due to the formation of fixed, tight junctions between the
sarcoplasmic reticulum (SR) and the sarcolemma where Ca2+ release is activated. Here, we tested the hypothesis that the SR is a structurally inert organelle in ventricular myocytes. Our data suggest that rather than being static, the SR undergoes frequent dynamic structural changes. SR boutons expressing functional ryanodine receptors moved throughout the cell, approaching or moving away from the sarcolemma of ventricular myocytes. These changes in SR structure occurred in the absence of changes in [Ca2+]i during EC coupling. Microtubules and the molecular motors dynein and kinesin 1(Kif5b) were important regulators of SR motility. These findings support a model in which the SR is a motile organelle capable of molecular motor protein-driven structural changes.
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26
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White E. Mechanical modulation of cardiac microtubules. Pflugers Arch 2011; 462:177-84. [DOI: 10.1007/s00424-011-0963-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2011] [Revised: 03/28/2011] [Accepted: 03/28/2011] [Indexed: 11/25/2022]
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27
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Leão KE, Leão RN, Deardorff AS, Garrett A, Fyffe R, Walmsley B. Sound stimulation modulates high-threshold K(+) currents in mouse auditory brainstem neurons. Eur J Neurosci 2010; 32:1658-67. [PMID: 20946234 DOI: 10.1111/j.1460-9568.2010.07437.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The auditory system provides a valuable experimental model to investigate the role of sensory activity in regulating neuronal membrane properties. In this study, we have investigated the role of activity directly by measuring changes in medial nucleus of the trapezoid body (MNTB) neurons in normal hearing mice subjected to 1-h sound stimulation. Broadband (4-12 kHz) chirps were used to activate MNTB neurons tonotopically restricted to the lateral MNTB, as confirmed by c-Fos-immunoreactivity. Following 1-h sound stimulation a substantial increase in Kv3.1b-immunoreactivity was measured in the lateral region of the MNTB, which lasted for 2 h before returning to control levels. Electrophysiological patch-clamp recordings in brainstem slices revealed an increase in high-threshold potassium currents in the lateral MNTB of sound-stimulated mice. Current-clamp and dynamic-clamp experiments showed that MNTB cells from the sound-stimulated mice were able to maintain briefer action potentials during high-frequency firing than cells from control mice. These results provide evidence that acoustically driven auditory activity can selectively regulate high-threshold potassium currents in the MNTB of normal hearing mice, likely due to an increased membrane expression of Kv3.1b channels.
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Affiliation(s)
- Katarina E Leão
- The John Curtin School of Medical Research, Australian National University, Canberra ACT, Australia
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28
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Dou Y, Balse E, Dehghani Zadeh A, Wang T, Goonasekara CL, Noble GP, Eldstrom J, Steele DF, Hatem SN, Fedida D. Normal targeting of a tagged Kv1.5 channel acutely transfected into fresh adult cardiac myocytes by a biolistic method. Am J Physiol Cell Physiol 2010; 298:C1343-52. [PMID: 20357183 DOI: 10.1152/ajpcell.00005.2010] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The transfection of cardiac myocytes is difficult, and so most of the data regarding the regulation of trafficking and targeting of cardiac ion channels have been obtained using heterologous expression systems. Here we apply the fast biolistic transfection procedure to adult cardiomyocytes to show that biolistically introduced exogenous voltage-gated potassium channel, Kv1.5, is functional and, like endogenous Kv1.5, localizes to the intercalated disc, where it is expressed at the surface of that structure. Transfection efficiency averages 28.2 +/- 5.7% of surviving myocytes at 24 h postbombardment. Ventricular myocytes transfected with a tagged Kv1.5 exhibit an increased sustained current component that is approximately 40% sensitive to 100 microM 4-aminopyridine and which is absent in myocytes transfected with a fluorescent protein-encoding construct alone. Kv1.5 deletion mutations known to reduce the surface expression of the channel in heterologous cells similarly reduce the surface expression in transfected ventricular myocytes, although targeting to the intercalated disc per se is generally unaffected by both NH(2)- and COOH-terminal deletion mutants. Expressed current levels in wild-type Kv1.5, Kv1.5DeltaSH3(1), Kv1.5DeltaN209, and Kv1.5DeltaN135 mutants were well correlated with apparent surface expression of the channel at the intercalated disc. Our results conclusively demonstrate functionality of channels present at the intercalated disc in native myocytes and identify determinants of trafficking and surface targeting in intact cells. Clearly, biolistic transfection of adult cardiac myocytes will be a valuable method to study the regulation of surface expression of channels in their native environment.
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Affiliation(s)
- Ying Dou
- Department of Anesthesiology, University of British Columbia, Vancouver, BC, Canada
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29
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Casini S, Tan HL, Demirayak I, Remme CA, Amin AS, Scicluna BP, Chatyan H, Ruijter JM, Bezzina CR, van Ginneken ACG, Veldkamp MW. Tubulin polymerization modifies cardiac sodium channel expression and gating. Cardiovasc Res 2009; 85:691-700. [PMID: 19861310 DOI: 10.1093/cvr/cvp352] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
AIMS Treatment with the anticancer drug taxol (TXL), which polymerizes the cytoskeleton protein tubulin, may evoke cardiac arrhythmias based on reduced human cardiac sodium channel (Na(v)1.5) function. Therefore, we investigated whether enhanced tubulin polymerization by TXL affects Na(v)1.5 function and expression and whether these effects are beta1-subunit-mediated. METHODS AND RESULTS Human embryonic kidney (HEK293) cells, transfected with SCN5A cDNA alone (Na(v)1.5) or together with SCN1B cDNA (Na(v)1.5 + beta1), and neonatal rat cardiomyocytes (NRCs) were incubated in the presence and in the absence of 100 microM TXL. Sodium current (I(Na)) characteristics were studied using patch-clamp techniques. Na(v)1.5 membrane expression was determined by immunocytochemistry and confocal microscopy. Pre-treatment with TXL reduced peak I(Na) amplitude nearly two-fold in both Na(v)1.5 and Na(v)1.5 + beta1, as well as in NRCs, compared with untreated cells. Accordingly, HEK293 cells and NRCs stained with anti-Na(v)1.5 antibody revealed a reduced membrane-labelling intensity in the TXL-treated groups. In addition, TXL accelerated I(Na) decay of Na(v)1.5 + beta1, whereas I(Na) decay of Na(v)1.5 remained unaltered. Finally, TXL reduced the fraction of channels that slow inactivated from 31% to 18%, and increased the time constant of slow inactivation by two-fold in Na(v)1.5. Conversely, slow inactivation properties of Na(v)1.5 + beta1 were unchanged by TXL. CONCLUSION Enhanced tubulin polymerization reduces sarcolemmal Na(v)1.5 expression and I(Na) amplitude in a beta1-subunit-independent fashion and causes I(Na) fast and slow inactivation impairment in a beta1-subunit-dependent way. These changes may underlie conduction-slowing-dependent cardiac arrhythmias under conditions of enhanced tubulin polymerization, e.g. TXL treatment and heart failure.
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Affiliation(s)
- Simona Casini
- Department of Clinical and Experimental Cardiology, Heart Failure Research Center, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands
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Cholesterol modulates the recruitment of Kv1.5 channels from Rab11-associated recycling endosome in native atrial myocytes. Proc Natl Acad Sci U S A 2009; 106:14681-6. [PMID: 19706553 DOI: 10.1073/pnas.0902809106] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Cholesterol is an important determinant of cardiac electrical properties. However, underlying mechanisms are still poorly understood. Here, we examine the hypothesis that cholesterol modulates the turnover of voltage-gated potassium channels based on previous observations showing that depletion of membrane cholesterol increases the atrial repolarizing current I(Kur). Whole-cell currents and single-channel activity were recorded in rat adult atrial myocytes (AAM) or after transduction with hKv1.5-EGFP. Channel mobility and expression were studied using fluorescence recovery after photobleaching (FRAP) and 3-dimensional microscopy. In both native and transduced-AAMs, the cholesterol-depleting agent MbetaCD induced a delayed ( approximately 7 min) increase in I(Kur); the cholesterol donor LDL had an opposite effect. Single-channel recordings revealed an increased number of active Kv1.5 channels upon MbetaCD application. Whole-cell recordings indicated that this increase was not dependent on new synthesis but on trafficking of existing pools of intracellular channels whose exocytosis could be blocked by both N-ethylmaleimide and nonhydrolyzable GTP analogues. Rab11 was found to coimmunoprecipitate with hKv1.5-EGFP channels and transfection with Rab11 dominant negative (DN) but not Rab4 DN prevented the MbetaCD-induced I(Kur) increase. Three-dimensional microscopy showed a decrease in colocalization of Kv1.5 and Rab11 in MbetaCD-treated AAM. These results suggest that cholesterol regulates Kv1.5 channel expression by modulating its trafficking through the Rab11-associated recycling endosome. Therefore, this compartment provides a submembrane pool of channels readily available for recruitment into the sarcolemma of myocytes. This process could be a major mechanism for the tuning of cardiac electrical properties and might contribute to the understanding of cardiac effects of lipid-lowering drugs.
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31
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Zadeh AD, Cheng Y, Xu H, Wong N, Wang Z, Goonasekara C, Steele DF, Fedida D. Kif5b is an essential forward trafficking motor for the Kv1.5 cardiac potassium channel. J Physiol 2009; 587:4565-74. [PMID: 19675065 DOI: 10.1113/jphysiol.2009.178442] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
We have investigated the role of the kinesin I isoform Kif5b in the trafficking of a cardiac voltage-gated potassium channel, Kv1.5. In Kv1.5-expressing HEK293 cells and H9c2 cardiomyoblasts, current densities were increased from control levels of 389 +/- 50.0 and 317 +/- 50.3 pA pF(1), respectively, to 614 +/- 74.3 and 580 +/- 90.9 pA pF(1) in cells overexpressing the Kif5b motor. Overexpression of the Kif5b motor increased Kv1.5 expression additively with several manipulations that reduce channel internalization, suggesting that it is involved in the delivery of the channel to the cell surface. In contrast, expression of a Kif5b dominant negative (Kif5bDN) construct increased Kv1.5 expression non-additively with these manipulations. Thus, the dominant negative acts by indirectly inhibiting endocytosis. The increase in Kv1.5 currents induced by wild-type Kif5b was dependent on Golgi function; a 6 h treatment with Brefeldin A reduced Kv1.5 currents to control levels in Kif5b-overexpressing cells but had little effect on the increase associated with Kif5bDN expression. Finally, expression of the Kif5bDN prior to induction of Kv1.5 in a tetracycline inducible system blocked surface expression of the channel in both HEK293 cells and H9c2 cardiomyoblasts. Thus, Kif5b is essential to anterograde trafficking of a cardiac voltage-gated potassium channel.
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Affiliation(s)
- Alireza Dehghani Zadeh
- Department of Anesthesiology, Pharmacology and Therapeutics, University of British Columbia, 2350 Health Sciences Mall, Vancouver, British Columbia, Canada V6T 1Z3
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32
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Nattel S, Frelin Y, Gaborit N, Louault C, Demolombe S. Ion-channel mRNA-expression profiling: Insights into cardiac remodeling and arrhythmic substrates. J Mol Cell Cardiol 2009; 48:96-105. [PMID: 19631654 DOI: 10.1016/j.yjmcc.2009.07.016] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/06/2009] [Revised: 06/17/2009] [Accepted: 07/09/2009] [Indexed: 11/20/2022]
Abstract
Membrane ion channels and transporters are key determinants of cardiac electrical function. Their expression is affected by cardiac region, hemodynamic properties, heart-rate changes, neurohormones and cardiac disease. One of the important determinants of ion-channel function is the level of ion-channel subunit mRNA expression, which governs the production of ion-channel proteins that traffic to the cell-membrane to form functional ion-channels. Ion-channel mRNA-expression profiling can be performed with cDNA microarrays or high-throughput reverse transcription/polymerase chain reaction (PCR) methods. Expression profiling has been applied to evaluate the dependence of ion-channel expression on cardiac region, revealing the molecular basis of regionally-controlled electrical properties as well as the molecular determinants of specialized electrical functions like pacemaking activity. Ion-channel remodeling occurs with cardiac diseases like heart failure, congenital repolarization abnormalities, and atrial fibrillation, and expression profiling has provided insights into the mechanisms by which these conditions affect cardiac electrical stability. Expression profiling has also shown how hormonal changes, antiarrhythmic drugs, cardiac development and altered heart rate affect ion-channel expression patterns to modify cardiac electrical function and sometimes to produce cardiac rhythm disturbances. This article reviews the information obtained to date with the application of cardiac ion-channel expression profiling. With increasing availability and efficiency of high-throughput PCR methods for ion-channel subunit mRNA-expression characterization, it is likely that the application of ion-channel expression profiling will increase and that it will provide important new insights into the determinants of cardiac electrical function in both physiological and pathological situations.
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Affiliation(s)
- Stanley Nattel
- Department of Medicine and Research Center, Montreal Heart Institute, Université de Montréal, Canada.
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