Cardiac myocyte

Tesfaye Negash Asfaw, Leonid Tyan, Alexey Glukhov, Vladimir E Bondarenko
Various experimental mouse models are extensively used to research human diseases including atrial fibrillation, the most common cardiac rhythm disorder. Despite this, there are no comprehensive mathematical models that describe the complex behavior of the action potential and [Ca2+ ]i transients in mouse atrial myocytes. Here, we develop a novel compartmentalized mathematical model of mouse atrial myocytes which combines the action potential, [Ca2+ ]i dynamics, and β-adrenergic signaling cascade for a subpopulation of right atrial myocytes with developed transverse-axial tubule system...
January 17, 2020: American Journal of Physiology. Heart and Circulatory Physiology
Kun-Sheng Li, Wei-Peng Jiang, Qiu-Chang Li, Hao-Wen Zhang, Yang Bai, Xia Zhang, Hai-Ying Li
BACKGROUND: Mesenchymal stem cells (MSCs) are under consideration for myocardial ischemia-reperfusion (I/R) injury therapy, but their mechanism remains to be evaluated. In this article, we aimed to study the effects of the miR-29a/follistatin-like 1 axis in bone marrow-derived mesenchymal stem cells on modulating myocyte apoptosis after hypoxia-reoxygenation (H/R) injury. METHODS: An in vitro myocardial ischemia-reperfusion injury model of H9c2 cells was developed by hypoxia-reoxygenation injury...
November 19, 2019: Cardiovascular Pathology: the Official Journal of the Society for Cardiovascular Pathology
Lettine van den Brink, Karina O Brandão, Loukia Yiangou, Mervyn P H Mol, Catarina Grandela, Christine L Mummery, Arie O Verkerk, Richard P Davis
Human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) have emerged as a powerful platform for in vitro modelling of cardiac diseases, safety pharmacology and drug screening. All these applications require large quantities of well-characterised and standardised batches of hiPSC-CMs. Cryopreservation of hiPSC-CMs without affecting their biochemical or biophysical phenotype is essential for facilitating this, but ideally requires the cells being unchanged by the freeze-thaw procedure. We therefore compared the in vitro functional and molecular characteristics of fresh and cryopreserved hiPSC-CMs generated from multiple independent hiPSC lines...
January 7, 2020: Stem Cell Research
Duilio Michele Potenza, Radoslav Janicek, Miguel Fernandez-Tenorio, Ernst Niggli
KEY POINTS: Increased protein phosphatase 1 (PP-1) activity has been found in end stage human heart failure. Although PP-1 has been extensively studied, a detailed understanding of its role in the excitation-contraction coupling mechanism, in the normal and diseased heart, remains elusive. The present work investigates the functional effect of the PP-1 activity on local Ca2+ release events in ventricular cardiomyocytes, by using an activating peptide (PDP3) for the stimulation of the endogenous PP-1 protein...
January 15, 2020: Journal of Physiology
Hiroyuki Minato, Ichiro Hisatome, Yasutaka Kurata, Tomomi Notsu, Naoe Nakasone, Haruaki Ninomiya, Toshihiro Hamada, Takuya Tomomori, Akihiro Okamura, Junichiro Miake, Motokazu Tsuneto, Yasuaki Shirayoshi, Ryo Endo, Akihiro Otsuki, Futoshi Okada, Yoshimi Inagaki
Myocardial ischemia/reperfusion injury worsens in the absence of nitric oxide synthase (NOS). Cilnidipine, a Ca2+ channel blocker, has been reported to activate endothelial NOS (eNOS) and increases nitric oxide (NO) in vascular endothelial cells. We examined whether pretreatment with cilnidipine could attenuate cardiac cell deaths including apoptosis caused by hypoxia/reoxygenation (H/R) injury. HL-1 mouse atrial myocytes as well as H9c2 rat ventricular cells were exposed to H/R, and cell viability was evaluated by an autoanalyzer and flow cytometry; eNOS expression, NO production, and electrophysiological properties were also evaluated by western blotting, colorimetry, and patch clamping, respectively, in the absence and presence of cilnidipine...
January 15, 2020: Hypertension Research: Official Journal of the Japanese Society of Hypertension
Sarbjot Kaur, Xin Shen, Amelia Power, Marie-Louise Ward
The mechanical response of the heart to myocardial stretch has been understood since the work of muscle physiologists more than 100 years ago, whereby an increase in ventricular chamber filling during diastole increases the subsequent force of contraction. The stretch-induced increase in contraction is biphasic. There is an abrupt increase in the force that coincides with the stretch (the rapid response), which is then followed by a slower response that develops over several minutes (the slow force response, or SFR)...
January 14, 2020: Biophysical Reviews
Ming Zhou, Kiwamu Yoshikawa, Hideo Akashi, Mitsutaka Miura, Ryoji Suzuki, Tao-Sheng Li, Hiroshi Abe, Yoshio Bando
BACKGROUND: ATP-sensitive K+ (KATP ) channels were originally found in cardiac myocytes by Noma in 1983. KATP channels were formed by potassium ion-passing pore-forming subunits (Kir6.1, Kir6.2) and regulatory subunits SUR1, SU2A and SUR2B. A number of cells and tissues have been revealed to contain these channels including hepatocytes, but detailed localization of these subunits in different types of liver cells was still uncertain. AIM: To investigate the expression of KATP channel subunits in rat liver and their localization in different cells of the liver...
December 19, 2019: World Journal of Experimental Medicine
Marianna Meo, Olivier Meste, Sergio Signore, Marcello Rota
The profile of the action potential (AP) of cardiomyocytes contributes to the modality of ventricular repolarization of the heart. Experimentally, the examination of the AP in isolated cardiomyocytes provides information on their electrical properties, adaptations to physiological and pathological conditions, and putative ionic mechanisms involved in the process. Currently, there are no available platforms for automated assessment of AP properties and standard methodologies restrict the examination of the AP repolarization to discrete, user-defined ranges, neglecting significant intervals of the electrical recovery...
May 2019: Biomedical Signal Processing and Control
Qing Li, Zhenyu Zhai, Juxiang Li
Stable electrical activity in cardiac myocytes is the basis of maintaining normal myocardial systolic and diastolic function. Cardiac ionic currents and their associated regulatory proteins are crucial to myocyte excitability and heart function. Fibroblast growth factor homologous factors (FHFs) are intracellular noncanonical fibroblast growth factors (FGFs) that are incapable of activating FGF receptors. The main functions of FHFs are to regulate ion channels and influence excitability, which are processes involved in sustaining normal cardiac function...
January 11, 2020: European Journal of Pharmacology
Aintzane Alday, Hasna Ahyayauch, Victor Fernández-López, Leyre Echeazarra, Janire Urrutia, Oscar Casis, Mónica Gallego
BACKGROUND/AIMS: To test whether the physiological regulation of the cardiac Kv4 channels by the Ca2+ /calmodulin-dependent protein kinase II (CaMKII) is restricted to lipid rafts and whether the interactions observed in rat cardiomyocytes also occur in the human ventricle. METHODS: Ventricular myocytes were freshly isolated from Sprague-Dawley rats. Ito was recorded by the whole-cell Patch-Clamp technique. Membrane rafts were isolated by centrifugation in a discontinuous sucrose density gradient...
January 15, 2020: Cellular Physiology and Biochemistry
Chan W Kim, Wilbert S Aronow, Tanya Dutta, Daniel Frenkel, William H Frishman
Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a rare congenital arrhythmogenic disorder induced by physical or emotional stress. It mainly affects children and younger adults and is characterized by rapid polymorphic and bidirectional ventricular tachycardia. Symptoms can include dizziness, palpitations, and presyncope, which may progress to syncope, hypotonia, convulsive movements, and sudden cardiac death. CPVT is the result of perturbations in Ca ion handling in the sarcoplasmic reticulum of cardiac myocytes...
January 2, 2020: Cardiology in Review
Joshua A Walker, Sean Richards, Mostafa E Belghasem, Nkiruka Arinze, Sung Bok Yoo, Joseph Y Tashjian, Stephen A Whelan, Norman Lee, Vijaya B Kolachalama, Jean Francis, Katya Ravid, David Sherr, Vipul C Chitalia
Emerging evidence in animal models of chronic kidney disease (CKD) implicates Aryl Hydrocarbon Receptor (AHR) signaling as a mediator of uremic toxicity. However, details about its tissue-specific and time-dependent activation in response to various renal pathologies remain poorly defined. Here, a comprehensive analysis of AHR induction was conducted in response to discrete models of kidney diseases using a transgenic mouse line expressing the AHR responsive-promoter tethered to a β-galactosidase reporter gene...
October 30, 2019: Kidney International
Heather L Struckman, Stephen Baine, Justin Thomas, Louisa Mezache, Kirk Mykytyn, Sándor Györke, Przemysław B Radwański, Rengasayee Veeraraghavan
The voltage-gated sodium channel [pore-forming subunit of the neuronal voltage-gated sodium channel (NaV1.6)] has recently been found in cardiac myocytes. Emerging studies indicate a role for NaV1.6 in ionic homeostasis as well as arrhythmogenesis. Little is known about the spatial organization of these channels in cardiac muscle, mainly due to the lack of high-fidelity antibodies. Therefore, we developed and rigorously validated a novel rabbit polyclonal NaV1.6 antibody and undertook super-resolution microscopy studies of NaV1...
January 14, 2020: Microscopy and Microanalysis
Anju Zuo, Xiaoyu Zhao, Tingting Li, Jun Li, Shengyun Lei, Jiying Chen, Dan Xu, Chengxiang Song, Tianjiao Liu, Cuigang Li, Yuan Guo
CTRP9 has been reported to regulate lipid metabolism and exert cardioprotective effects, yet its role in high-fat diet (HFD)-induced cardiac lipotoxicity and the underlying mechanisms remain unclear. In the current study, we established HFD-induced obesity model in wild-type (WT) or CTRP9 knockout (CTRP9-KO) mice and palmitate-induced lipotoxicity model in neonatal rat cardiac myocytes (NRCMs) to investigate the effects of CTRP9 on cardiac lipotoxicity. Our results demonstrated that the HFD-fed CTRP9-KO mice accentuated cardiac hypertrophy, fibrosis, endoplasmic reticulum (ER) stress-initiated apoptosis and oxidative stress compared with the HFD-fed WT mice...
January 13, 2020: Journal of Cellular and Molecular Medicine
Xu Tian, Ning Zhou, Jie Yuan, Le Lu, Qi Zhang, Minmin Wei, Yunzeng Zou, Lingyan Yuan
Exercise training is believed to have a positive effect on cardiac hypertrophy after hypertension. However, its mechanism is still not fully understood. Herein, our findings suggest that heat shock transcription factor 1 (HSF1) improves exercise-initiated myocardial angiogenesis after pressure overload. A sustained narrowing of the diagonal aorta (TAC) and moderately- intense exercise training protocol were imposed on HSF1 heterozygote (KO) and their littermate wild-type (WT) male mice. After two months, the cardiac function was assessed using the adaptive responses to exercise training, or TAC, or both of them such as catheterization and echocardiography...
January 12, 2020: Journal of Cellular and Molecular Medicine
Ya-Ya Du, Li Zou, Xiu-Xiu Wang, Le-Yao Dai, Xin-Nan Ling, Zheng-Xin Xu
Gallic acid (GA) has a protective effect on the cardiovascular system. To study its cardiac electrophysiological effects, voltage-gated Na+ channel currents (INa ) were recorded in rat cardiomyocytes using whole-cell patch clamp techniques. Moreover, the effects of GA on aconitine-induced arrhythmias were assessed using electrocardiograms in vivo. We found that the current-voltage characteristic curve (I-V curve) of INa significantly shifted in the presence of 1, 3, and 10 μmol/L of GA. The peak sodium current density (INa -Peak) was reduced from -84...
January 10, 2020: Clinical and Experimental Pharmacology & Physiology
Y Gartshteyn, M Tamargo, S Fleischer, T Kapoor, J Li, A Askanase, R Winchester, L Geraldino-Pardilla
BACKGROUND: Endomyocardial biopsy (EMB) is considered the gold standard for diagnosing myocardial involvement in most inflammatory conditions, including systemic lupus erythematosus (SLE). However, EMBs are rarely performed, and most of the myocardial histopathology reports in SLE consist of postmortem data. We therefore sought to describe the histopathologic findings of contemporary EMBs in SLE performed in clinical practice. METHODS: A retrospective review of histopathology reports from SLE patients who underwent EMB from 1994 to 2017 was performed...
January 10, 2020: Lupus
Yansong Li, Shuhong Ren, Jingwen Xia, Yong Wei, Yinhua Xi
Acute myocardial infarction (AMI) results from long-term diminished blood supply diminishment (ischemia) to the heart, and the main reason for ischemia is hypoxia. BCL2 interaction protein 3 (BNIP3) can be upregulated by hypoxia and participates in the mediation of hypoxia-activated apoptosis in cardiac myocyte death. The purpose of this study was to interrogate the mechanism of BNIP3 in hypoxia-activated cardiac myocyte injury. Cell viability and apoptosis were evaluated by Cell counting kit 8 (CCK-8), 5-ethynyl-2'-deoxyuridine (EdU), TdT-mediated dUTP Nick-End Labeling (TUNEL), and caspase-3 activity assays...
November 26, 2019: Molecular Therapy. Nucleic Acids
Hanping Qi, Jing Ren, Lina Ba, Chao Song, Qianhui Zhang, Yonggang Cao, Pilong Shi, Bowen Fu, Yongsheng Liu, Hongli Sun
Cardiac hypertrophy, a response of the heart to increased workload, is a major risk factor for heart failure. Myostatin (MSTN) is an inhibitor of myogenesis, regulating the number and size of skeletal myocytes. In recent years, cardiomyocyte autophagy also has been considered to be involved in controlling the hypertrophic response. However, less is known about the detailed mechanism of MSTN on cardiac hypertrophy via regulation of cardiomyocyte autophagy. In this study, we found that the deletion of MSTN potentiated abdominal aorta coarctation (AAC) and angiotensin II (Ang II)-induced pathological cardiac hypertrophy and cardiac autophagy; however, AAC and Ang II-induced cardiac hypertrophic phenotype and cardiac autophagy were dramatically diminished by MSTN in vivo and in vitro...
December 14, 2019: Molecular Therapy. Nucleic Acids
Parisa Asghari, David Rl Scriven, Myles Ng, Pankaj Panwar, Keng C Chou, Filip van Petegem, Edwin Dw Moore
The effects of the immunophilins, FKBP12 and FKBP12.6, and phosphorylation on type II ryanodine receptor (RyR2) arrangement and function were examined using correlation microscopy (line scan confocal imaging of Ca2+ sparks and dual-tilt electron tomography) and dSTORM imaging of permeabilized Wistar rat ventricular myocytes. Saturating concentrations (10 µmol/L) of either FKBP12 or 12.6 significantly reduced the frequency, spread, amplitude and Ca2+ spark mass relative to control, while the tomograms revealed both proteins shifted the tetramers into a largely side-by-side configuration...
January 9, 2020: ELife
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