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Ghareeb AFA, Foutz JC, Schneiders GH, Richter JN, Milfort MC, Fuller AL, Rekaya R, Aggrey SE. Host transcriptome response to heat stress and Eimeria maxima infection in meat-type chickens. PLoS One 2024; 19:e0296350. [PMID: 38394169 PMCID: PMC10889870 DOI: 10.1371/journal.pone.0296350] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Accepted: 12/05/2023] [Indexed: 02/25/2024] Open
Abstract
Eimeria (E.) maxima parasite infects chickens' midgut disrupting the jejunal and ileal mucosa causing high morbidity and mortality. Heat stress (HS) is a seasonal stressor that impacts biological functions leading to poor performance. This study elucidates how HS, E. maxima infection, and their combination affect the ileum transcriptome. Two-hundred and forty 2-week-old males Ross708 chickens were randomly allocated into four treatment groups: thermoneutral-control (TNc), thermoneutral-infected (TNi), heat-stress control (HSc), and heat stress-infected (HSi), with 6 replicates each of 10 birds. Infected groups received 200x103 sporulated E. maxima oocysts/bird, and heat-treated groups were raised at 35°C. At 6-day post-treatment, ileums of five randomly selected chickens per group were sampled, RNA was extracted and sequenced. A total of 413, 3377, 1908, and 2304 DEGs were identified when applying the comparisons: TNc vs HSc, TNc vs TNi, HSi vs HSc, and TNi vs HSi, respectively, at cutoff ≥1.2-fold change (FDR: q<0.05). HSc vs TNc showed upregulation of lipid metabolic pathways and degradation/metabolism of multiple amino acids; and downregulation of most immune-related and protein synthesis pathways. TNc vs TNi displayed upregulation of most of immune-associated pathways and eukaryotic mRNA maturation pathways; and downregulation of fatty acid metabolism and multiple amino acid metabolism pathways including tryptophan. Comparing HSi versus HSc and TNi revealed that combining the two stressors restored the expression of some cellular functions, e.g., oxidative phosphorylation and protein synthesis; and downregulate immune response pathways associated with E. maxima infection. During E. maxima infection under HS the calcium signaling pathway was downregulated, including genes responsible for increasing the cytoplasmic calcium concentration; and tryptophan metabolism was upregulated, including genes that contribute to catabolizing tryptophan through serotonin and indole pathways; which might result in reducing the cytoplasmic pool of nutrients and calcium available for the parasite to scavenge and consequently might affect the parasite's reproductive ability.
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Affiliation(s)
- Ahmed F. A. Ghareeb
- NutriGenomics Laboratory, Department of Poultry Science, University of Georgia, Athens, Georgia, United States of America
| | - James C. Foutz
- NutriGenomics Laboratory, Department of Poultry Science, University of Georgia, Athens, Georgia, United States of America
| | - Gustavo H. Schneiders
- NutriGenomics Laboratory, Department of Poultry Science, University of Georgia, Athens, Georgia, United States of America
| | - Jennifer N. Richter
- NutriGenomics Laboratory, Department of Poultry Science, University of Georgia, Athens, Georgia, United States of America
| | - Marie C. Milfort
- NutriGenomics Laboratory, Department of Poultry Science, University of Georgia, Athens, Georgia, United States of America
| | - Alberta L. Fuller
- NutriGenomics Laboratory, Department of Poultry Science, University of Georgia, Athens, Georgia, United States of America
| | - Romdhane Rekaya
- Department of Animal and Dairy Science, University of Georgia, Athens, Georgia, United States of America
| | - Samuel E. Aggrey
- NutriGenomics Laboratory, Department of Poultry Science, University of Georgia, Athens, Georgia, United States of America
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Maurya S, Mills RW, Kahnert K, Chiang DY, Bertoli G, Lundegaard PR, Duran MPH, Zhang M, Rothenberg E, George AL, MacRae CA, Delmar M, Lundby A. Outlining cardiac ion channel protein interactors and their signature in the human electrocardiogram. NATURE CARDIOVASCULAR RESEARCH 2023; 2:673-692. [PMID: 38666184 PMCID: PMC11041666 DOI: 10.1038/s44161-023-00294-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Accepted: 05/31/2023] [Indexed: 04/28/2024]
Abstract
Protein-protein interactions are essential for normal cellular processes and signaling events. Defining these interaction networks is therefore crucial for understanding complex cellular functions and interpretation of disease-associated gene variants. We need to build a comprehensive picture of the interactions, their affinities and interdependencies in the specific organ to decipher hitherto poorly understood signaling mechanisms through ion channels. Here we report the experimental identification of the ensemble of protein interactors for 13 types of ion channels in murine cardiac tissue. Of these, we validated the functional importance of ten interactors on cardiac electrophysiology through genetic knockouts in zebrafish, gene silencing in mice, super-resolution microscopy and patch clamp experiments. Furthermore, we establish a computational framework to reconstruct human cardiomyocyte ion channel networks from deep proteome mapping of human heart tissue and human heart single-cell gene expression data. Finally, we integrate the ion channel interactome with human population genetics data to identify proteins that influence the electrocardiogram (ECG). We demonstrate that the combined channel network is enriched for proteins influencing the ECG, with 44% of the network proteins significantly associated with an ECG phenotype. Altogether, we define interactomes of 13 major cardiac ion channels, contextualize their relevance to human electrophysiology and validate functional roles of ten interactors, including two regulators of the sodium current (epsin-2 and gelsolin). Overall, our data provide a roadmap for our understanding of the molecular machinery that regulates cardiac electrophysiology.
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Affiliation(s)
- Svetlana Maurya
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Robert W. Mills
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Konstantin Kahnert
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - David Y. Chiang
- Cardiovascular Medicine Division, Brigham and Women’s Hospital and Harvard Medical School, Boston, MA USA
| | - Giorgia Bertoli
- Division of Cardiology, NYU School of Medicine, New York, NY USA
| | - Pia R. Lundegaard
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | | | - Mingliang Zhang
- Division of Cardiology, NYU School of Medicine, New York, NY USA
| | - Eli Rothenberg
- Division of Pharmacology, NYU School of Medicine, New York, NY USA
| | - Alfred L. George
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL USA
| | - Calum A. MacRae
- Cardiovascular Medicine Division, Brigham and Women’s Hospital and Harvard Medical School, Boston, MA USA
| | - Mario Delmar
- Division of Cardiology, NYU School of Medicine, New York, NY USA
| | - Alicia Lundby
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- The Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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3
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Fender H, Walter K, Kiper AK, Plačkić J, Kisko TM, Braun MD, Schwarting RKW, Rohrbach S, Wöhr M, Decher N, Kockskämper J. Calcium Handling Remodeling Underlies Impaired Sympathetic Stress Response in Ventricular Myocardium from Cacna1c Haploinsufficient Rats. Int J Mol Sci 2023; 24:9795. [PMID: 37372947 DOI: 10.3390/ijms24129795] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Revised: 05/27/2023] [Accepted: 05/31/2023] [Indexed: 06/29/2023] Open
Abstract
CACNA1C encodes the pore-forming α1C subunit of the L-type Ca2+ channel, Cav1.2. Mutations and polymorphisms of the gene are associated with neuropsychiatric and cardiac disease. Haploinsufficient Cacna1c+/- rats represent a recently developed model with a behavioral phenotype, but its cardiac phenotype is unknown. Here, we unraveled the cardiac phenotype of Cacna1c+/- rats with a main focus on cellular Ca2+ handling mechanisms. Under basal conditions, isolated ventricular Cacna1c+/- myocytes exhibited unaltered L-type Ca2+ current, Ca2+ transients (CaTs), sarcoplasmic reticulum (SR) Ca2+ load, fractional release, and sarcomere shortenings. However, immunoblotting of left ventricular (LV) tissue revealed reduced expression of Cav1.2, increased expression of SERCA2a and NCX, and augmented phosphorylation of RyR2 (at S2808) in Cacna1c+/- rats. The β-adrenergic agonist isoprenaline increased amplitude and accelerated decay of CaTs and sarcomere shortenings in both Cacna1c+/- and WT myocytes. However, the isoprenaline effect on CaT amplitude and fractional shortening (but not CaT decay) was impaired in Cacna1c+/- myocytes exhibiting both reduced potency and efficacy. Moreover, sarcolemmal Ca2+ influx and fractional SR Ca2+ release after treatment with isoprenaline were smaller in Cacna1c+/- than in WT myocytes. In Langendorff-perfused hearts, the isoprenaline-induced increase in RyR2 phosphorylation at S2808 and S2814 was attenuated in Cacna1c+/- compared to WT hearts. Despite unaltered CaTs and sarcomere shortenings, Cacna1c+/- myocytes display remodeling of Ca2+ handling proteins under basal conditions. Mimicking sympathetic stress with isoprenaline unmasks an impaired ability to stimulate Ca2+ influx, SR Ca2+ release, and CaTs caused, in part, by reduced phosphorylation reserve of RyR2 in Cacna1c+/- cardiomyocytes.
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Affiliation(s)
- Hauke Fender
- Institute of Pharmacology and Clinical Pharmacy, Faculty of Pharmacy, Biochemical and Pharmacological Center (BPC) Marburg, University of Marburg, 35032 Marburg, Germany
| | - Kim Walter
- Institute of Pharmacology and Clinical Pharmacy, Faculty of Pharmacy, Biochemical and Pharmacological Center (BPC) Marburg, University of Marburg, 35032 Marburg, Germany
| | - Aytug K Kiper
- Institute of Physiology and Pathophysiology, Vegetative Physiology, University of Marburg, 35037 Marburg, Germany
- Center for Mind, Brain and Behavior (CMBB), University of Marburg, 35032 Marburg, Germany
| | - Jelena Plačkić
- Institute of Pharmacology and Clinical Pharmacy, Faculty of Pharmacy, Biochemical and Pharmacological Center (BPC) Marburg, University of Marburg, 35032 Marburg, Germany
| | - Theresa M Kisko
- Behavioral Neuroscience, Experimental and Biological Psychology, University of Marburg, 35032 Marburg, Germany
| | - Moria D Braun
- Behavioral Neuroscience, Experimental and Biological Psychology, University of Marburg, 35032 Marburg, Germany
| | - Rainer K W Schwarting
- Center for Mind, Brain and Behavior (CMBB), University of Marburg, 35032 Marburg, Germany
- Behavioral Neuroscience, Experimental and Biological Psychology, University of Marburg, 35032 Marburg, Germany
| | - Susanne Rohrbach
- Institute of Physiology, University of Gießen, 35392 Giessen, Germany
| | - Markus Wöhr
- Center for Mind, Brain and Behavior (CMBB), University of Marburg, 35032 Marburg, Germany
- Behavioral Neuroscience, Experimental and Biological Psychology, University of Marburg, 35032 Marburg, Germany
- Social and Affective Neuroscience Research Group, Laboratory of Biological Psychology, Research Unit Brain and Cognition, Faculty of Psychology and Educational Sciences, KU Leuven, B-3000 Leuven, Belgium
- Leuven Brain Institute, KU Leuven, B-3000 Leuven, Belgium
| | - Niels Decher
- Institute of Physiology and Pathophysiology, Vegetative Physiology, University of Marburg, 35037 Marburg, Germany
- Center for Mind, Brain and Behavior (CMBB), University of Marburg, 35032 Marburg, Germany
| | - Jens Kockskämper
- Institute of Pharmacology and Clinical Pharmacy, Faculty of Pharmacy, Biochemical and Pharmacological Center (BPC) Marburg, University of Marburg, 35032 Marburg, Germany
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Liu Z, Chen X, Ye T, Wan W, Yu Y, Zhang C, Yang B. Pinocembrin alleviates the susceptibility to atrial fibrillation in isoproterenol-induced rats. Biochem Biophys Res Commun 2022; 636:33-40. [DOI: 10.1016/j.bbrc.2022.10.036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Revised: 10/01/2022] [Accepted: 10/10/2022] [Indexed: 11/02/2022]
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5
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Ferron L, Zamponi GW. The road to the brain in Timothy syndrome is paved with enhanced CaV1.2 activation gating. J Gen Physiol 2022; 154:213558. [PMID: 36264243 PMCID: PMC9587385 DOI: 10.1085/jgp.202213272] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Specific gating effects of Timothy syndrome CaV1.2 channel mutations determine cardiovascular versus nervous system deficits.
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Affiliation(s)
- Laurent Ferron
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Canada
| | - Gerald W Zamponi
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Canada
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6
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Rupee S, Rupee K, Singh RB, Hanoman C, Ismail AMA, Smail M, Singh J. Diabetes-induced chronic heart failure is due to defects in calcium transporting and regulatory contractile proteins: cellular and molecular evidence. Heart Fail Rev 2022; 28:627-644. [PMID: 36107271 DOI: 10.1007/s10741-022-10271-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 09/07/2022] [Indexed: 11/04/2022]
Abstract
Heart failure (HF) is a major deteriorating disease of the myocardium due to weak myocardial muscles. As such, the heart is unable to pump blood efficiently around the body to meet its constant demand. HF is a major global health problem with more than 7 million deaths annually worldwide, with some patients dying suddenly due to sudden cardiac death (SCD). There are several risk factors which are associated with HF and SCD which can negatively affect the heart synergistically. One major risk factor is diabetes mellitus (DM) which can cause an elevation in blood glucose level or hyperglycaemia (HG) which, in turn, has an insulting effect on the myocardium. This review attempted to explain the subcellular, cellular and molecular mechanisms and to a lesser extent, the genetic factors associated with the development of diabetes- induced cardiomyopathy due to the HG which can subsequently lead to chronic heart failure (CHF) and SCD. The study first explained the structure and function of the myocardium and then focussed mainly on the excitation-contraction coupling (ECC) processes highlighting the defects of calcium transporting (SERCA, NCX, RyR and connexin) and contractile regulatory (myosin, actin, titin and troponin) proteins. The study also highlighted new therapies and those under development, as well as preventative strategies to either treat or prevent diabetic cardiomyopathy (DCM). It is postulated that prevention is better than cure.
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Increased cytosolic calcium buffering contributes to a cellular arrhythmogenic substrate in iPSC-cardiomyocytes from patients with dilated cardiomyopathy. Basic Res Cardiol 2022; 117:5. [PMID: 35499658 PMCID: PMC9061684 DOI: 10.1007/s00395-022-00912-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 01/14/2022] [Accepted: 01/17/2022] [Indexed: 01/31/2023]
Abstract
Dilated cardiomyopathy (DCM) is a major risk factor for heart failure and is associated with the development of life-threatening cardiac arrhythmias. Using a patient-specific induced pluripotent stem cell-derived cardiomyocyte (iPSC-CM) model harbouring a mutation in cardiac troponin T (R173W), we aim to examine the cellular basis of arrhythmogenesis in DCM patients with this mutation. iPSC from control (Ctrl) and DCM-TnT-R173W donors from the same family were differentiated into iPSC-CM and analysed through optical action potential (AP) recordings, simultaneous measurement of cytosolic calcium concentration ([Ca2+]i) and membrane currents and separately assayed using field stimulation to detect the threshold for AP- and [Ca2+]i-alternans development. AP duration was unaltered in TnT-R173W iPSC-CM. Nevertheless, TnT-R173W iPSC-CM showed a strikingly low stimulation threshold for AP- and [Ca2+]i-alternans. Myofilaments are known to play a role as intracellular Ca2+ buffers and here we show increased Ca2+ affinity of intracellular buffers in TnT-R173W cells, indicating increased myofilament sensitivity to Ca2+. Similarly, EMD57033, a myofilament Ca2+ sensitiser, replicated the abnormal [Ca2+]i dynamics observed in TnT-R173W samples and lowered the threshold for alternans development. In contrast, application of a Ca2+ desensitiser (blebbistatin) to TnT-R173W iPSC-CM was able to phenotypically rescue Ca2+ dynamics, normalising Ca2+ transient profile and minimising the occurrence of Ca2+ alternans at physiological frequencies. This finding suggests that increased Ca2+ buffering likely plays a major arrhythmogenic role in patients with DCM, specifically in those with mutations in cardiac troponin T. In addition, we propose that modulation of myofilament Ca2+ sensitivity could be an effective anti-arrhythmic target for pharmacological management of this disease.
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8
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Li X, Tian G, Xu L, Sun L, Tao R, Zhang S, Cong Z, Deng F, Chen J, Yu Y, Du W, Zhao H. Wenxin Keli for the Treatment of Arrhythmia-Systems Pharmacology and In Vivo Pharmacological Assessment. Front Pharmacol 2021; 12:704622. [PMID: 34512338 PMCID: PMC8426352 DOI: 10.3389/fphar.2021.704622] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Accepted: 07/21/2021] [Indexed: 12/13/2022] Open
Abstract
This study employed a systems pharmacology approach to identify the active compounds and action mechanisms of Wenxin Keli for arrhythmia treatment. Sixty-eight components identified in vivo and in vitro by UPLC/Q-TOF-MS were considered the potential active components of Wenxin Keli. Network pharmacology further revealed 33 key targets and 75 KEGG pathways as possible pathways and targets involved in WK-mediated treatment, with the CaMKII/CNCA1C/Ca2+ pathway being the most significantly affected. This finding was validated using an AC-induced rat arrhythmias model. Pretreatment with Wenxin Keli reduced the malignant arrhythmias and shortened RR, PR, and the QT interval. Wenxin Keli exerted some antiarrhythmic effects by inhibiting p-CaMKII and intracellular Ca2+ transients and overexpressing CNCA1C. Thus, suppressing SR Ca2+ release and maintaining intracellular Ca2+ balance may be the primary mechanism of Wenxin Keli against arrhythmia. In view of the significance of CaMKII and NCX identified in this experiment, we suggest that CaMKII and NCX are essential targets for treating arrhythmias.
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Affiliation(s)
- Xiaofeng Li
- Department of Cardiology, The Second Affiliated Hospital of Tianjin University of TCM, Tianjin, China
| | - Gang Tian
- Department of Cardiology, Teda International Cardiovascular Hospital, Tianjin, China
| | - Liang Xu
- School of Pharmacy, Tianjin Medical University, Tianjin, China.,Tianjin Medical College, Tianjin, China
| | - Lili Sun
- Department of TCM, Tianjin University of TCM, Tianjin, China
| | - Rui Tao
- Department of TCM, Tianjin University of TCM, Tianjin, China
| | - Shaoqiang Zhang
- Department of Cardiology, The Second Affiliated Hospital of Tianjin University of TCM, Tianjin, China
| | - Zidong Cong
- Department of Cardiology, The Second Affiliated Hospital of Tianjin University of TCM, Tianjin, China
| | - Fangjun Deng
- Department of TCM, Tianjin University of TCM, Tianjin, China
| | - Jinhong Chen
- Department of TCM, Tianjin University of TCM, Tianjin, China
| | - Yang Yu
- Department of Aeronautics and Astronautics, Tsinghua University, Beijing, China
| | - Wuxun Du
- Department of Cardiology, The Second Affiliated Hospital of Tianjin University of TCM, Tianjin, China
| | - Hucheng Zhao
- Department of Aeronautics and Astronautics, Tsinghua University, Beijing, China
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9
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Effect of Verapamil, an L-Type Calcium Channel Inhibitor, on Caveolin-3 Expression in Septic Mouse Hearts. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2021; 2021:6667074. [PMID: 33927797 PMCID: PMC8052133 DOI: 10.1155/2021/6667074] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Revised: 03/04/2021] [Accepted: 03/23/2021] [Indexed: 12/29/2022]
Abstract
Sepsis-induced myocardial dysfunction considerably increases mortality risk in patients with sepsis. Previous studies from our group have shown that sepsis alters the expression of structural proteins in cardiac cells, resulting in cardiomyocyte degeneration and impaired communication between cardiac cells. Caveolin-3 (CAV3) is a structural protein present in caveolae, located in the membrane of cardiac muscle cells, which regulates physiological processes such as calcium homeostasis. In sepsis, there is a disruption of calcium homeostasis, which increases the concentration of intracellular calcium, which can lead to the activation of potent cellular enzymes/proteases which cause severe cellular injury and death. The purpose of the present study was to test the hypotheses that sepsis induces CAV3 overexpression in the heart, and the regulation of L-type calcium channels directly relates to the regulation of CAV3 expression. Severe sepsis increases the expression of CAV3 in the heart, as immunostaining in our study showed CAV3 presence in the cardiomyocyte membrane and cytoplasm, in comparison with our control groups (without sepsis) that showed CAV3 presence predominantly in the plasma membrane. The administration of verapamil, an L-type calcium channel inhibitor, resulted in a decrease in mortality rates of septic mice. This effect was accompanied by a reduction in the expression of CAV3 and attenuation of cardiac lesions in septic mice treated with verapamil. Our results indicate that CAV3 has a vital role in cardiac dysfunction development in sepsis and that the regulation of L-type calcium channels may be related to its expression.
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10
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Yun W, Qian L, Cheng Y, Tao W, Yuan R, Xu H. Periplocymarin Plays an Efficacious Cardiotonic Role via Promoting Calcium Influx. Front Pharmacol 2020; 11:1292. [PMID: 32973521 PMCID: PMC7466735 DOI: 10.3389/fphar.2020.01292] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Accepted: 08/04/2020] [Indexed: 12/28/2022] Open
Abstract
Periplocymarin, which belongs to cardiac glycosides, is an effective component extracted from Periplocae Cortex. However, its cardiovascular effects remain unidentified. In the present study, injection of periplocymarin (5 mg/kg) through external jugular vein immediately increased the mean arterial pressure (MAP) in anesthetized C57BL/6 mice. Ex vivo experiments using mouse mesenteric artery rings were conducted to validate the role of periplocymarin on blood vessels. However, periplocymarin failed to induce vasoconstriction directly, and had no effects on vasoconstriction induced by phenylephrine (Phe) and angiotensin II (Ang II). In addition, vasodilatation induced by acetylcholine (Ach) was insusceptible to periplocymarin. Echocardiography was used to evaluate the effects of periplocymarin on cardiac function. The results showed that the injection of periplocymarin significantly increase the ejection fraction (EF) in mice without changing the heart rate. In vitro studies using isolated neonatal rat ventricular myocytes (NRVMs) revealed that periplocymarin transiently increased the intracellular Ca2+ concentration observed by confocal microscope. But in Ca2+-free buffer, this phenomenon vanished. Besides, inhibition of sodium potassium-activated adenosine triphosphatase (Na+-K+-ATPase) by digoxin significantly suppressed the increase of MAP and EF in mice, and the influx of Ca2+ in cardiomyocytes, mediated by periplocymarin. Collectively, these findings demonstrated that periplocymarin increased the contractility of myocardium by promoting the Ca2+ influx of cardiomyocytes via targeting on Na+-K+-ATPase, which indirectly led to the instantaneous rise of blood pressure.
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Affiliation(s)
- Weijing Yun
- Advanced Institute for Medical Sciences, Dalian Medical University, Dalian, China
| | - Lei Qian
- Advanced Institute for Medical Sciences, Dalian Medical University, Dalian, China
| | - Yanyan Cheng
- Advanced Institute for Medical Sciences, Dalian Medical University, Dalian, China
| | - Weiwei Tao
- College of Nursing, Dalian Medical University, Dalian, China
| | - Ruqiang Yuan
- Advanced Institute for Medical Sciences, Dalian Medical University, Dalian, China
| | - Hu Xu
- Advanced Institute for Medical Sciences, Dalian Medical University, Dalian, China
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11
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Sanchez-Alonso JL, Loucks A, Schobesberger S, van Cromvoirt AM, Poulet C, Chowdhury RA, Trayanova N, Gorelik J. Nanoscale regulation of L-type calcium channels differentiates between ischemic and dilated cardiomyopathies. EBioMedicine 2020; 57:102845. [PMID: 32580140 PMCID: PMC7317229 DOI: 10.1016/j.ebiom.2020.102845] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 05/19/2020] [Accepted: 06/03/2020] [Indexed: 10/26/2022] Open
Abstract
BACKGROUND Subcellular localization and function of L-type calcium channels (LTCCs) play an important role in regulating contraction of cardiomyocytes. Understanding how this is affected by the disruption of transverse tubules during heart failure could lead to new insights into the disease. METHODS Cardiomyocytes were isolated from healthy donor hearts, as well as from patients with cardiomyopathies and with left ventricular assist devices. Scanning ion conductance and confocal microscopy was used to study membrane structures in the cells. Super-resolution scanning patch-clamp was used to examine LTCC function in different microdomains. Computational modeling predicted the impact of these changes to arrhythmogenesis at the whole-heart level. FINDINGS We showed that loss of structural organization in failing myocytes leads to re-distribution of functional LTCCs from the T-tubules to the sarcolemma. In ischemic cardiomyopathy, the increased LTCC open probability in the T-tubules depends on the phosphorylation by protein kinase A, whereas in dilated cardiomyopathy, the increased LTCC opening probability in the sarcolemma results from enhanced phosphorylation by calcium-calmodulin kinase II. LVAD implantation corrected LTCCs pathophysiological activity, although it did not improve their distribution. Using computational modeling in a 3D anatomically-realistic human ventricular model, we showed how LTCC location and activity can trigger heart rhythm disorders of different severity. INTERPRETATION Our findings demonstrate that LTCC redistribution and function differentiate between disease aetiologies. The subcellular changes observed in specific microdomains could be the consequence of the action of distinct protein kinases. FUNDING This work was supported by NIH grant (ROI-HL 126802 to NT-JG) and British Heart Foundation (grant RG/17/13/33173 to JG, project grant PG/16/17/32069 to RAC). Funders had no role in study design, data collection, data analysis, interpretation, writing of the report.
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Affiliation(s)
- Jose L Sanchez-Alonso
- Department of Cardiovascular Sciences, Imperial Centre for Translational and Experimental Medicine, National Heart and Lung Institute, Imperial College London, London W120NN, UK
| | - Alexandra Loucks
- Department of Biomedical Engineering and Alliance for Cardiovascular Diagnostic and Treatment Innovation, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Sophie Schobesberger
- Department of Cardiovascular Sciences, Imperial Centre for Translational and Experimental Medicine, National Heart and Lung Institute, Imperial College London, London W120NN, UK
| | - Ankie M van Cromvoirt
- Department of Cardiovascular Sciences, Imperial Centre for Translational and Experimental Medicine, National Heart and Lung Institute, Imperial College London, London W120NN, UK
| | - Claire Poulet
- Department of Cardiovascular Sciences, Imperial Centre for Translational and Experimental Medicine, National Heart and Lung Institute, Imperial College London, London W120NN, UK
| | - Rasheda A Chowdhury
- Department of Cardiovascular Sciences, Imperial Centre for Translational and Experimental Medicine, National Heart and Lung Institute, Imperial College London, London W120NN, UK
| | - Natalia Trayanova
- Department of Biomedical Engineering and Alliance for Cardiovascular Diagnostic and Treatment Innovation, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Julia Gorelik
- Department of Cardiovascular Sciences, Imperial Centre for Translational and Experimental Medicine, National Heart and Lung Institute, Imperial College London, London W120NN, UK.
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12
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Shi M, Tien NT, de Haan L, Louisse J, Rietjens IMCM, Bouwmeester H. Evaluation of in vitro models of stem cell-derived cardiomyocytes to screen for potential cardiotoxicity of chemicals. Toxicol In Vitro 2020; 67:104891. [PMID: 32446838 DOI: 10.1016/j.tiv.2020.104891] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Revised: 05/14/2020] [Accepted: 05/16/2020] [Indexed: 12/12/2022]
Abstract
Cardiotoxicity is an important toxicological endpoint for chemical and drug safety assessment. The present study aims to evaluate two stemcell-based in vitro models for cardiotoxicity screening of chemicals. Eleven model compounds were used to evaluate responses of mouse embryonic stem cell-derived cardiomyocytes (mESC-CMs) using beating arrest as a readout and the analysis of electrophysiological parameters measured with a multi-electrode array (MEA) platform of human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs). Results revealed that the hiPSC-CM MEA assay responded to all compounds. The mESC-CM beating arrest assay was not responsive to potassium channel blockers and showed a lower sensitivity to sodium channel blockers and Na+/K+ ATPase inhibitors compared to the hiPSC-CM MEA assay. Calcium channel blockers and a β-adrenergic receptor agonist showed comparable potencies in both models. The in vitro response concentrations from hiPSC-CMs were highly concordant with human effective serum concentrations of potassium and sodium channel blockers. It is concluded that both in vitro models enable the cardiotoxicity screening with different applicability domains. The mESC-CM beating arrest assay may be used as a first step in a tiered approach while the hiPSC-CM MEA assay may be the best starting point for quantitative in vitro to in vivo extrapolations.
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Affiliation(s)
- Miaoying Shi
- Division of Toxicology, Wageningen University, P.O. box 8000, 6700, EA, Wageningen, the Netherlands.
| | - Nguyen T Tien
- Division of Toxicology, Wageningen University, P.O. box 8000, 6700, EA, Wageningen, the Netherlands
| | - Laura de Haan
- Division of Toxicology, Wageningen University, P.O. box 8000, 6700, EA, Wageningen, the Netherlands.
| | - Jochem Louisse
- Division of Toxicology, Wageningen University, P.O. box 8000, 6700, EA, Wageningen, the Netherlands.
| | - Ivonne M C M Rietjens
- Division of Toxicology, Wageningen University, P.O. box 8000, 6700, EA, Wageningen, the Netherlands.
| | - Hans Bouwmeester
- Division of Toxicology, Wageningen University, P.O. box 8000, 6700, EA, Wageningen, the Netherlands.
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13
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Noble M, Lin QT, Sirko C, Houpt JA, Novello MJ, Stathopulos PB. Structural Mechanisms of Store-Operated and Mitochondrial Calcium Regulation: Initiation Points for Drug Discovery. Int J Mol Sci 2020; 21:E3642. [PMID: 32455637 PMCID: PMC7279490 DOI: 10.3390/ijms21103642] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Revised: 05/11/2020] [Accepted: 05/17/2020] [Indexed: 12/18/2022] Open
Abstract
Calcium (Ca2+) is a universal signaling ion that is essential for the life and death processes of all eukaryotes. In humans, numerous cell stimulation pathways lead to the mobilization of sarco/endoplasmic reticulum (S/ER) stored Ca2+, resulting in the propagation of Ca2+ signals through the activation of processes, such as store-operated Ca2+ entry (SOCE). SOCE provides a sustained Ca2+ entry into the cytosol; moreover, the uptake of SOCE-mediated Ca2+ by mitochondria can shape cytosolic Ca2+ signals, function as a feedback signal for the SOCE molecular machinery, and drive numerous mitochondrial processes, including adenosine triphosphate (ATP) production and distinct cell death pathways. In recent years, tremendous progress has been made in identifying the proteins mediating these signaling pathways and elucidating molecular structures, invaluable for understanding the underlying mechanisms of function. Nevertheless, there remains a disconnect between using this accumulating protein structural knowledge and the design of new research tools and therapies. In this review, we provide an overview of the Ca2+ signaling pathways that are involved in mediating S/ER stored Ca2+ release, SOCE, and mitochondrial Ca2+ uptake, as well as pinpoint multiple levels of crosstalk between these pathways. Further, we highlight the significant protein structures elucidated in recent years controlling these Ca2+ signaling pathways. Finally, we describe a simple strategy that aimed at applying the protein structural data to initiating drug design.
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Affiliation(s)
- Megan Noble
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, ON N6A5C1, Canada; (M.N.); (Q.-T.L.); (C.S.); (M.J.N.)
| | - Qi-Tong Lin
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, ON N6A5C1, Canada; (M.N.); (Q.-T.L.); (C.S.); (M.J.N.)
| | - Christian Sirko
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, ON N6A5C1, Canada; (M.N.); (Q.-T.L.); (C.S.); (M.J.N.)
| | - Jacob A. Houpt
- Department of Medicine, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, ON N6A5C1, Canada;
| | - Matthew J. Novello
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, ON N6A5C1, Canada; (M.N.); (Q.-T.L.); (C.S.); (M.J.N.)
| | - Peter B. Stathopulos
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, ON N6A5C1, Canada; (M.N.); (Q.-T.L.); (C.S.); (M.J.N.)
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14
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Bohannon BM, de la Cruz A, Wu X, Jowais JJ, Perez ME, Dykxhoorn DM, Liin SI, Larsson HP. Polyunsaturated fatty acid analogues differentially affect cardiac Na V, Ca V, and K V channels through unique mechanisms. eLife 2020; 9:51453. [PMID: 32207683 PMCID: PMC7159882 DOI: 10.7554/elife.51453] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Accepted: 03/24/2020] [Indexed: 12/15/2022] Open
Abstract
The cardiac ventricular action potential depends on several voltage-gated ion channels, including NaV, CaV, and KV channels. Mutations in these channels can cause Long QT Syndrome (LQTS) which increases the risk for ventricular fibrillation and sudden cardiac death. Polyunsaturated fatty acids (PUFAs) have emerged as potential therapeutics for LQTS because they are modulators of voltage-gated ion channels. Here we demonstrate that PUFA analogues vary in their selectivity for human voltage-gated ion channels involved in the ventricular action potential. The effects of specific PUFA analogues range from selective for a specific ion channel to broadly modulating cardiac ion channels from all three families (NaV, CaV, and KV). In addition, a PUFA analogue selective for the cardiac IKs channel (Kv7.1/KCNE1) is effective in shortening the cardiac action potential in human-induced pluripotent stem cell-derived cardiomyocytes. Our data suggest that PUFA analogues could potentially be developed as therapeutics for LQTS and cardiac arrhythmia.
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Affiliation(s)
- Briana M Bohannon
- Department of Physiology and Biophysics, Miller School of Medicine, University of Miami, Miami, United States
| | - Alicia de la Cruz
- Department of Physiology and Biophysics, Miller School of Medicine, University of Miami, Miami, United States
| | - Xiaoan Wu
- Department of Physiology and Biophysics, Miller School of Medicine, University of Miami, Miami, United States
| | - Jessica J Jowais
- Department of Physiology and Biophysics, Miller School of Medicine, University of Miami, Miami, United States
| | - Marta E Perez
- Department of Physiology and Biophysics, Miller School of Medicine, University of Miami, Miami, United States
| | - Derek M Dykxhoorn
- John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, United States
| | - Sara I Liin
- Department of Biomedical and Clinical Sciences, Linköping University, Linköping, Sweden
| | - H Peter Larsson
- Department of Physiology and Biophysics, Miller School of Medicine, University of Miami, Miami, United States
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15
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Al Kury LT. Calcium Homeostasis in Ventricular Myocytes of Diabetic Cardiomyopathy. J Diabetes Res 2020; 2020:1942086. [PMID: 33274235 PMCID: PMC7683117 DOI: 10.1155/2020/1942086] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 10/24/2020] [Accepted: 10/29/2020] [Indexed: 12/12/2022] Open
Abstract
Diabetes mellitus (DM) is a chronic metabolic disorder commonly characterized by high blood glucose levels, resulting from defects in insulin production or insulin resistance, or both. DM is a leading cause of mortality and morbidity worldwide, with diabetic cardiomyopathy as one of its main complications. It is well established that cardiovascular complications are common in both types of diabetes. Electrical and mechanical problems, resulting in cardiac contractile dysfunction, are considered as the major complications present in diabetic hearts. Inevitably, disturbances in the mechanism(s) of Ca2+ signaling in diabetes have implications for cardiac myocyte contraction. Over the last decade, significant progress has been made in outlining the mechanisms responsible for the diminished cardiac contractile function in diabetes using different animal models of type I diabetes mellitus (TIDM) and type II diabetes mellitus (TIIDM). The aim of this review is to evaluate our current understanding of the disturbances of Ca2+ transport and the role of main cardiac proteins involved in Ca2+ homeostasis in the diabetic rat ventricular cardiomyocytes. Exploring the molecular mechanism(s) of altered Ca2+ signaling in diabetes will provide an insight for the identification of novel therapeutic approaches to improve the heart function in diabetic patients.
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Affiliation(s)
- Lina T. Al Kury
- Department of Health Sciences, College of Natural and Health Sciences, Zayed University, Abu Dhabi 144534, UAE
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16
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RBM20 Regulates CaV1.2 Surface Expression by Promoting Exon 9* Inclusion of CACNA1C in Neonatal Rat Cardiomyocytes. Int J Mol Sci 2019; 20:ijms20225591. [PMID: 31717392 PMCID: PMC6888234 DOI: 10.3390/ijms20225591] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 11/05/2019] [Accepted: 11/06/2019] [Indexed: 01/25/2023] Open
Abstract
The CACNA1C gene encodes for the CaV1.2 protein, which is the pore subunit of cardiac l-type voltage-gated calcium (Ca2+) channels (l-channels). Through alternative splicing, CACNA1C encodes for various CaV1.2 isoforms with different electrophysiological properties. Splice variants of CaV1.2 are differentially expressed during heart development or pathologies. The molecular mechanisms of CACNA1C alternative splicing still remain incompletely understood. RNA sequencing analysis has suggested that CACNA1C is a potential target of the splicing factor RNA-binding protein motif 20 (RBM20). Here, we aimed at elucidating the role of RBM20 in the regulation of CACNA1C alternative splicing. We found that in neonatal rat cardiomyocytes (NRCMs), RBM20 overexpression promoted the inclusion of CACNA1C’s exon 9*, whereas the skipping of exon 9* occurred upon RBM20 siRNA knockdown. The splicing of other known alternative exons was not altered by RBM20. RNA immunoprecipitation suggested that RBM20 binds to introns flanking exon 9*. Functionally, in NRCMs, RBM20 overexpression decreased l-type Ca2+ currents, whereas RBM20 siRNA knockdown increased l-type Ca2+ currents. Finally, we found that RBM20 overexpression reduced CaV1.2 membrane surface expression in NRCMs. Taken together, our results suggest that RBM20 specifically regulates the inclusion of exon 9* in CACNA1C mRNA, resulting in reduced cell-surface membrane expression of l-channels in cardiomyocytes.
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17
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Vierra NC, Kirmiz M, van der List D, Santana LF, Trimmer JS. Kv2.1 mediates spatial and functional coupling of L-type calcium channels and ryanodine receptors in mammalian neurons. eLife 2019; 8:49953. [PMID: 31663850 PMCID: PMC6839919 DOI: 10.7554/elife.49953] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Accepted: 10/29/2019] [Indexed: 12/16/2022] Open
Abstract
The voltage-gated K+ channel Kv2.1 serves a major structural role in the soma and proximal dendrites of mammalian brain neurons, tethering the plasma membrane (PM) to endoplasmic reticulum (ER). Although Kv2.1 clustering at neuronal ER-PM junctions (EPJs) is tightly regulated and highly conserved, its function remains unclear. By identifying and evaluating proteins in close spatial proximity to Kv2.1-containing EPJs, we discovered that a significant role of Kv2.1 at EPJs is to promote the clustering and functional coupling of PM L-type Ca2+ channels (LTCCs) to ryanodine receptor (RyR) ER Ca2+ release channels. Kv2.1 clustering also unexpectedly enhanced LTCC opening at polarized membrane potentials. This enabled Kv2.1-LTCC-RyR triads to generate localized Ca2+ release events (i.e., Ca2+ sparks) independently of action potentials. Together, these findings uncover a novel mode of LTCC regulation and establish a unique mechanism whereby Kv2.1-associated EPJs provide a molecular platform for localized somatodendritic Ca2+ signals in mammalian brain neurons.
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Affiliation(s)
- Nicholas C Vierra
- Department of Physiology and Membrane Biology, School of Medicine, University of California, Davis, Davis, United States.,Department of Neurobiology, Physiology, and Behavior, University of California, Davis, Davis, United States
| | - Michael Kirmiz
- Department of Neurobiology, Physiology, and Behavior, University of California, Davis, Davis, United States
| | - Deborah van der List
- Department of Physiology and Membrane Biology, School of Medicine, University of California, Davis, Davis, United States.,Department of Neurobiology, Physiology, and Behavior, University of California, Davis, Davis, United States
| | - L Fernando Santana
- Department of Physiology and Membrane Biology, School of Medicine, University of California, Davis, Davis, United States
| | - James S Trimmer
- Department of Physiology and Membrane Biology, School of Medicine, University of California, Davis, Davis, United States.,Department of Neurobiology, Physiology, and Behavior, University of California, Davis, Davis, United States
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18
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Qu YS, Lazzerini PE, Capecchi PL, Laghi-Pasini F, El Sherif N, Boutjdir M. Autoimmune Calcium Channelopathies and Cardiac Electrical Abnormalities. Front Cardiovasc Med 2019; 6:54. [PMID: 31119135 PMCID: PMC6507622 DOI: 10.3389/fcvm.2019.00054] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Accepted: 04/16/2019] [Indexed: 12/24/2022] Open
Abstract
Patients with autoimmune diseases are at increased risk for developing cardiovascular diseases, and abnormal electrocardiographic findings are common. Voltage-gated calcium channels play a major role in the cardiovascular system and regulate cardiac excitability and contractility. Particularly, by virtue of their localization and expression in the heart, calcium channels modulate pace making at the sinus node, conduction at the atrioventricular node and cardiac repolarization in the working myocardium. Consequently, emerging evidence suggests that calcium channels are targets to autoantibodies in autoimmune diseases. Autoimmune-associated cardiac calcium channelopathies have been recognized in both sinus node dysfunction atrioventricular block in patients positive for anti-Ro/La antibodies, and ventricular arrhythmias in patients with dilated cardiomyopathy. In this review, we discuss mechanisms of autoimmune-associated calcium channelopathies and their relationship with the development of cardiac electrical abnormalities.
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Affiliation(s)
- Yongxia Sarah Qu
- Department of Cardiology, New York Presbyterian Brooklyn Methodist Hospital, Brooklyn, NY, United States.,VA New York Harbor Healthcare System and State University of New York Downstate Medical Center, Brooklyn, NY, United States
| | - Pietro Enea Lazzerini
- Department of Medical Sciences, Surgery and Neurosciences, University of Siena, Siena, Italy
| | - Pier Leopoldo Capecchi
- Department of Medical Sciences, Surgery and Neurosciences, University of Siena, Siena, Italy
| | - Franco Laghi-Pasini
- Department of Medical Sciences, Surgery and Neurosciences, University of Siena, Siena, Italy
| | - Nabil El Sherif
- VA New York Harbor Healthcare System and State University of New York Downstate Medical Center, Brooklyn, NY, United States
| | - Mohamed Boutjdir
- VA New York Harbor Healthcare System and State University of New York Downstate Medical Center, Brooklyn, NY, United States.,NYU School of Medicine, New York, NY, United States
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19
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Nieto-Marín P, Jiménez-Jáimez J, Tinaquero D, Alfayate S, Utrilla RG, Rodríguez Vázquez del Rey MDM, Perin F, Sarquella-Brugada G, Monserrat L, Brugada J, Tercedor L, Tamargo J, Delpón E, Caballero R. La expresividad variable del síndrome de QT largo de una familia española se explica por la heterocigosis digénica en SCN5A y CACNA1C. Rev Esp Cardiol (Engl Ed) 2019. [DOI: 10.1016/j.recesp.2018.03.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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20
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An African loss-of-function CACNA1C variant p.T1787M associated with a risk of ventricular fibrillation. Sci Rep 2018; 8:14619. [PMID: 30279520 PMCID: PMC6168548 DOI: 10.1038/s41598-018-32867-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Accepted: 09/17/2018] [Indexed: 12/13/2022] Open
Abstract
Calcium regulation plays a central role in cardiac function. Several variants in the calcium channel Cav1.2 have been implicated in arrhythmic syndromes. We screened patients with Brugada syndrome, short QT syndrome, early repolarisation syndrome, and idiopathic ventricular fibrillation to determine the frequency and pathogenicity of Cav1.2 variants. Cav1.2 related genes, CACNA1C, CACNB2 and CACNA2D1, were screened in 65 probands. Missense variants were introduced in the Cav1.2 alpha subunit plasmid by mutagenesis to assess their pathogenicity using patch clamp approaches. Six missense variants were identified in CACNA1C in five individuals. Five of them, A1648T, A1689T, G1795R, R1973Q, C1992F, showed no major alterations of the channel function. The sixth C-terminal variant, Cavα1c-T1787M, present mostly in the African population, was identified in two patients with resuscitated cardiac arrest. The first patient originated from Cameroon and the second was an inhabitant of La Reunion Island with idiopathic ventricular fibrillation originating from Purkinje tissues. Patch-clamp analysis revealed that Cavα1c-T1787M reduces the calcium and barium currents by increasing the auto-inhibition mediated by the C-terminal part and increases the voltage-dependent inhibition. We identified a loss-of-function variant, Cavα1c-T1787M, present in 0.8% of the African population, as a new risk factor for ventricular arrhythmia.
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21
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Digenic Heterozigosity in SCN5A and CACNA1C Explains the Variable Expressivity of the Long QT Phenotype in a Spanish Family. ACTA ACUST UNITED AC 2018; 72:324-332. [PMID: 29691127 DOI: 10.1016/j.rec.2018.03.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Accepted: 03/06/2018] [Indexed: 11/20/2022]
Abstract
INTRODUCTION AND OBJECTIVES A known long QT syndrome-related mutation in Nav1.5 cardiac channels (p.R1644H) was found in 4 members of a Spanish family but only 1 of them showed prolongation of the QT interval. In the other 3 relatives, a novel missense mutation in Cav1.2 cardiac channels was found (p.S1961N). Here, we functionally analyzed p.S1961N Cav1.2 channels to elucidate whether this mutation regulates the expressivity of the long QT syndrome phenotype in this family. METHODS L-type calcium current (ICaL) recordings were performed by using the whole-cell patch-clamp technique in Chinese hamster ovary cells transiently transfected with native and/or p.S1961N Cav1.2 channels. RESULTS Expression of p.S1961N channels significantly decreased ICaL density. Using Ba as a charge carrier to suppress the Ca-dependent inactivation of Cav1.2 channels, we demonstrated that the mutation significantly accelerates the voltage-dependent inactivation of Cav1.2 channels decreasing the inactivation time constant. As a consequence, the total charge flowing through p.S1961N Cav1.2 channels significantly decreased. The effects of the p.S1961N Cav1.2 and p.R1644H Nav1.5 mutations alone or their combination on the action potential (AP) morphology were simulated using a validated model of the human ventricular AP. The p.S1961N Cav1.2 mutation shortens the AP duration and abrogates the prolongation induced by p.R1644H Nav1.5 channels. CONCLUSIONS The p.S1961N mutation in Cav1.2 channels decreased the ICaL, an effect which might shorten ventricular AP. The presence of the loss-of-function Cav1.2 mutation could functionally compensate the prolonging effects produced by the Nav1.5 gain-of-function mutation.
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22
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Ion channels as part of macromolecular multiprotein complexes : Clinical significance. Herzschrittmacherther Elektrophysiol 2017; 29:30-35. [PMID: 29214349 PMCID: PMC5846830 DOI: 10.1007/s00399-017-0542-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Accepted: 10/11/2017] [Indexed: 11/17/2022]
Abstract
Ion channels and Ca2+-handling proteins involved in the regulation of cardiac electrophysiology and contractility are organized in macromolecular multiprotein complexes. Recent molecular and cellular studies have significantly enhanced our understanding of the composition of these macromolecular complexes and have helped to elucidate their role in the dynamic regulation of ion channel function. Moreover, it has become clear that alterations in the composition of ion channel macromolecular complexes, for example, due to genetic mutations or acquired alterations in the expression of individual components, may lead to ion channel dysfunction and arrhythmogenesis. Here, we review novel insights into the composition of the major ion channel macromolecular complexes and discuss the potential clinical significance of alterations in these dynamic multiprotein structures.
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