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"ryanodine receptor" OR "ryr" OR "ryr2"

Kenichi Sasaki, Takeru Makiyama, Yoshinori Yoshida, Yimin Wuriyanghai, Tsukasa Kamakura, Suguru Nishiuchi, Mamoru Hayano, Takeshi Harita, Yuta Yamamoto, Hirohiko Kohjitani, Sayako Hirose, Jiarong Chen, Mihoko Kawamura, Seiko Ohno, Hideki Itoh, Ayako Takeuchi, Satoshi Matsuoka, Masaru Miura, Naokata Sumitomo, Minoru Horie, Shinya Yamanaka, Takeshi Kimura
INTRODUCTION: Human induced pluripotent stem cells (hiPSCs) offer a unique opportunity for disease modeling. However, it is not invariably successful to recapitulate the disease phenotype because of the immaturity of hiPSC-derived cardiomyocytes (hiPSC-CMs). The purpose of this study was to establish and analyze iPSC-based model of catecholaminergic polymorphic ventricular tachycardia (CPVT), which is characterized by adrenergically mediated lethal arrhythmias, more precisely using electrical pacing that could promote the development of new pharmacotherapies...
2016: PloS One
Naokata Sumitomo
Catecholaminergic polymorphic ventricular tachycardia (CPVT) is induced by emotions or exercise in patients without organic heart disease and may be polymorphic or bidirectional in nature. The prognosis of CPVT is not good, and therefore prevention of sudden death is of utmost importance. Genetic variants of CPVT include RyR2, CASQ2, CALM2, TRD, and possibly KCNJ2 and ANK2 gene mutations. Hypotheses that suggest the causes of CPVT include weakened binding of FKBP12.6 and RyR2, a store overload-induced Ca(2+) release (SOICR), unzipping of intramolecular domain interactions in RyR2, and molecular and functional abnormalities caused by mutations in the CASQ2 gene...
October 2016: Journal of Arrhythmia
Robyn T Rebbeck, Maram M Essawy, Florentin R Nitu, Benjamin D Grant, Gregory D Gillispie, David D Thomas, Donald M Bers, Razvan L Cornea
Using time-resolved fluorescence resonance energy transfer (FRET), we have developed and validated the first high-throughput screening (HTS) method to discover compounds that modulate an intracellular Ca(2+) channel, the ryanodine receptor (RyR), for therapeutic applications. Intracellular Ca(2+) regulation is critical for striated muscle function, and RyR is a central player. At resting [Ca(2+)], an increased propensity of channel opening due to RyR dysregulation is associated with severe cardiac and skeletal myopathies, diabetes, and neurological disorders...
October 19, 2016: Journal of Biomolecular Screening
Julia O Reynolds, Ann P Quick, Qiongling Wang, David L Beavers, Leonne E Philippen, Jordan Showell, Giselle Barreto-Torres, Donna J Thuerauf, Shirin Doroudgar, Christopher C Glembotski, Xander H T Wehrens
BACKGROUND: Junctophilin-2 (JPH2) is the primary structural protein for the coupling of transverse (T)-tubule associated cardiac L-type Ca channels and type-2 ryanodine receptors on the sarcoplasmic reticulum within junctional membrane complexes (JMCs) in cardiomyocytes. Effective signaling between these channels ensures adequate Ca-induced Ca release required for normal cardiac contractility. Disruption of JMC subcellular domains, a common feature of failing hearts, has been attributed to JPH2 downregulation...
October 8, 2016: International Journal of Cardiology
Yusuke Fujii, Hideki Itoh, Seiko Ohno, Takashi Murayama, Nagomi Kurebayashi, Hisaaki Aoki, Malorie Blancard, Yoshihisa Nakagawa, Satoshi Yamamoto, Yumie Matsui, Mari Ichikawa, Keiko Sonoda, Tomoya Ozawa, Kimie Ohkubo, Ichiro Watanabe, Pascale Guicheney, Minoru Horie
BACKGROUND: Ventricular fibrillation (VF) may be caused by premature ventricular contractions (PVCs) whose coupling intervals are under 300ms, a characteristic of scTdP. OBJECTIVE: The purpose of this study is to analyze the underlying RyR2 variants in patients with the short-coupled variant of torsade de pointes (scTdP). METHODS: Seven patients with scTdP (34±12 years old, 3 females) were enrolled in this study. The RyR2 gene was screened by targeted gene sequencing methods, and variant minor allele frequency (MAF) was confirmed in three databases, and the pathogenicity was investigated in multiple in silico tools...
October 15, 2016: Heart Rhythm: the Official Journal of the Heart Rhythm Society
Steven Hunt, Paul Hopkins, Nazeem Nanjee, Karen Schwander, Donald Kohan, D C Rao, Gordon Williams
OBJECTIVE: Identify the earliest hormonal, electrolyte and gene expression responses to a saline infusion before compensatory mechanisms are activated and relate these responses to delayed sodium excretion. DESIGN AND METHOD: 233 normotensive subjects with a strong positive family history of hypertension, ages 21-65, were studied on a low sodium diet before, during and after a 2-hour, 2-liter saline infusion. Plasma and urine hormones of the renin-angiotensin-aldosterone, catecholamine, uric acid, kallikrein, and cortisol pathways, microalbumin, and urine and plasma electrolytes were measured...
September 2016: Journal of Hypertension
Przemysław B Radwański, Hsiang-Ting Ho, Rengasayee Veeraraghavan, Lucia Brunello, Bin Liu, Andriy E Belevych, Sathya D Unudurthi, Michael A Makara, Silvia G Priori, Pompeo Volpe, Antonis A Armoundas, Wolfgang H Dillmann, Bjorn C Knollmann, Peter J Mohler, Thomas J Hund, Sándor Györke
BACKGROUND: Cardiac arrhythmias are a leading cause of death in the US. Vast majority of these arrhythmias including catecholaminergic polymorphic ventricular tachycardia (CPVT) are associated with increased levels of circulating catecholamines and involve abnormal impulse formation secondary to aberrant Ca(2+) and Na(+) handling. However, the mechanistic link between β-AR stimulation and the subcellular/molecular arrhythmogenic trigger(s) remains elusive. METHODS AND RESULTS: We performed functional and structural studies to assess Ca(2+) and Na(+) signaling in ventricular myocyte as well as surface electrocardiograms in mouse models of cardiac calsequestrin (CASQ2)-associated CPVT...
June 2016: JACC. Basic to Translational Science
Reza Ashrafi, Marianne Yon, Lucy Pickavance, Joseph Yanni Gerges, Gershan Davis, John Wilding, Kun Jian, Henggui Zhang, George Hart, Mark Boyett
Introduction. Obesity is increasingly common and is associated with an increased prevalence of cardiac arrhythmias. The aim of this study was to see whether in obesity there is proarrhythmic gene expression of ventricular ion channels and related molecules. Methods and Results. Rats were fed on a high-fat diet and compared to control rats on a normal diet (n = 8). After 8 weeks, rats on the high-fat diet showed significantly greater weight gain and higher adiposity. Left ventricle samples were removed at 8 weeks and mRNA expression of ion channels and other molecules was measured using qPCR...
2016: Journal of Obesity
Yong Xie, Zhen-Jie Gu, Mao-Xiong Wu, Tu-Cheng Huang, Jing-Song Ou, Huiping-Son Ni, Mao-Huan Lin, Wo-Liang Yuan, Jing-Feng Wang, Yang-Xin Chen
AIMS: Adverse cardiovascular effects induced by peroxisome proliferator activator receptor-γ (PPAR-γ) activation were observed in clinical setting. But the underlying mechanism is unclear. Now, transgenic mice with cardiac specific peroxisome proliferator activator receptor-γ overexpression (TG-PPAR-γ) were used to explore the possible mechanisms. MATERIALS AND METHODS: Cardiac tissues from TG-PPAR-γ mice, a PPAR-γ over-expressing human cardiomyocyte line AC16 cell, and PPAR-γ agonist-treated primary cardiomyocytes were used to evaluate the expression of cardiac calcium regulatory proteins as sarcoplasmic reticulum Ca(2+) ATPase, Na(+)/Ca(2+)exchanger 1, ryanodine receptor 2 and phospholamban...
October 13, 2016: Life Sciences
Yohannes Shiferaw
Spontaneous calcium (Ca) waves in cardiac myocytes are known to underlie a wide range of cardiac arrhythmias. However, it is not understood which physiological parameters determine the onset of waves. In this study, we explore the relationship between Ca signaling between ion channels and the nucleation of Ca waves. In particular, we apply a master equation approach to analyze the stochastic interaction between neighboring clusters of ryanodine receptor (RyR) channels. Using this analysis, we show that signaling between clusters can be described as a barrier hopping process with exponential sensitivity to system parameters...
September 2016: Physical Review. E
Jia-Ling Ruan, Nathaniel L Tulloch, Maria V Razumova, Mark Saiget, Veronica Muskheli, Lil Pabon, Hans Reinecke, Michael Regnier, Charles E Murry
BACKGROUNDS: -Tissue engineering enables the generation of functional human cardiac tissue using cells derived in vitro in combination with biocompatible materials. Human induced pluripotent stem cell (hiPSC)-derived cardiomyocytes provide a cell source for cardiac tissue engineering; however, their immaturity limits their potential applications. Here we sought to study the effect of mechanical conditioning and electrical pacing on the maturation of hiPSC-derived cardiac tissues. METHODSS: -Cardiomyocytes derived from hiPSCs were used to generate collagen-based bioengineered human cardiac tissue...
October 13, 2016: Circulation
Fábio V G Campanha, Denise Perone, Dijon H S de Campos, Renata de A M Luvizotto, Maria T De Síbio, Miriane de Oliveira, Regiane M C Olimpio, Fernanda C F Moretto, Carlos R Padovani, Gláucia M F S Mazeto, Antonio C Cicogna, Célia R Nogueira
Objective: The current study was aimed at analyzing sarcoplasmic reticulum Ca2+ ATPase (Serca2) and ryanodine receptor type 2 (Ryr2) gene expression in rats subjected to surgery that induced HF and were subsequently treated with T4 using physiological doses. Materials and methods: HF was induced in 18 male Wistar rats by clipping the ascending thoracic aorta to generate aortic stenosis (HFS group), while the control group (9-sham) underwent thoracotomy. After 21 weeks, the HFS group was subdivided into two subgroups...
October 10, 2016: Archives of Endocrinology and Metabolism
Zhichao Xiao, Wenting Guo, Bo Sun, Donald J Hunt, Jinhong Wei, Yingjie Liu, Yundi Wang, Ruiwu Wang, Peter P Jones, Thomas G Back, S R Wayne Chen
Recent three-dimensional structural studies reveal that the Central domain of ryanodine receptor (RyR) serves as a transducer that converts long-range conformational changes into the gating of the channel pore. Interestingly, the Central domain encompasses one of the mutation hotspots (corresponding to amino acid residues 3778-4201) that contains a number of cardiac RyR (RyR2) mutations associated with catecholaminergic polymorphic ventricular tachycardia (CPVT) and atrial fibrillation (AF). However, the functional consequences of these Central domain RyR2 mutations are not well understood...
October 12, 2016: Journal of Biological Chemistry
Kaivan Khavandi, Rachael L Baylie, Sarah A Sugden, Majid Ahmed, Viktoria Csato, Philip Eaton, David C Hill-Eubanks, Adrian D Bonev, Mark T Nelson, Adam S Greenstein
Activation of Ca(2+)-sensitive, large-conductance potassium (BK) channels in vascular smooth muscle cells (VSMCs) by local, ryanodine receptor-mediated Ca(2+) signals (Ca(2+) sparks) acts as a brake on pressure-induced (myogenic) vasoconstriction-a fundamental mechanism that regulates blood flow in small resistance arteries. We report that physiological intraluminal pressure within resistance arteries activated cGMP-dependent protein kinase (PKG) in VSMCs through oxidant-induced formation of an intermolecular disulfide bond between cysteine residues...
October 11, 2016: Science Signaling
Ann P Quick, Qiongling Wang, Leonne E Philippen, Giselle Barreto-Torres, David Y Chiang, David L Beavers, Guoliang Wang, Maha Khalid, Julia O Reynolds, Hannah M Campbell, Jordan Showell, Mark D McCauley, Arjen Scholten, Xander H Wehrens
RATIONALE: Junctional membrane complexes (JMC) in myocytes are critical microdomains, in which excitation-contraction coupling occurs. Structural and functional disruption of JMCs underlies contractile dysfunction in failing hearts. However, the role of newly identified JMC protein striated muscle preferentially expressed gene (SPEG) remains unclear. OBJECTIVE: To determine the role of SPEG in healthy and failing adult hearts. MMethods and Results: Proteomic analysis of immunoprecipatated JMC-proteins ryanodine receptor type-2 (RyR2) and junctophilin-2 (JPH2) followed by mass spectrometry identified the serine-threonine kinase SPEG as the only novel binding partner for both proteins...
October 11, 2016: Circulation Research
Donald M Bers
No abstract text is available yet for this article.
October 7, 2016: Heart Rhythm: the Official Journal of the Heart Rhythm Society
Zhangjiang He, Linli Luo, Nemat O Keyhani, Xiaodong Yu, Shenghua Ying, Yongjun Zhang
Protein O-mannosyltransferases (Pmts) belong to a highly conserved protein family responsible for the initiation of O-glycosylation of many proteins. Pmts contain one dolichyl-phosphate-mannose-protein mannosyltransferases (PMT) domain and three MIR motifs (mannosyltransferase, inositol triphosphate, and ryanodine receptor) that are essential for activity in yeast. We report that in the insect fungal pathogen, Beauveria bassiana, deletion of the C-terminal Pmt1 MIR-containing region (Pmt1∆ (311-902)) does not alter O-mannosyltransferase activity, but does increase total cell wall protein O-mannosylation levels and results in phenotypic changes in fungal development and cell wall stability...
October 8, 2016: Applied Microbiology and Biotechnology
Elzbieta Zieminska, Jacek Lenart, Dominik Diamandakis, Jerzy W Lazarewicz
Using primary cultures of rat cerebellar granule cells (CGC) we examined the role of calcium transients induced by tetrabromobisphenol A (TBBPA) in triggering oxidative stress and cytotoxicity. CGC were exposed for 30 min to 10 or 25 µM TBBPA. Changes in intracellular calcium concentration ([Ca(2+)]i), in the production of reactive oxygen species (ROS), and in the potential of mitochondria (∆Ψm) were measured fluorometrically during the exposure. The intracellular glutathione (GSH) and catalase activity were determined after the incubation; cell viability was evaluated 24 h later...
October 7, 2016: Neurochemical Research
R M Downs, M A Hughes, S T Kinsey, M C Johnson, B L Baumgarner
Caffeine is a widely consumed stimulant that has previously been shown to promote cytotoxic stress and even cell death in numerous mammalian cell lines. Thus far there is little information available regarding the toxicity of caffeine in skeletal muscle cells. Our preliminary data revealed that treating C2C12 myotubes with 5 mM caffeine for 6 h increased nuclear fragmentation and reduced basal and maximal oxygen consumption rate (OCR) in skeletal myotubes. The purpose of this study was to further elucidate the pathways by which caffeine increased cell death and reduced mitochondrial respiration...
October 4, 2016: Biochemical and Biophysical Research Communications
Seigo Sugimachi, Yukihisa Matsumoto, Makoto Mizunami, Jiro Okada
Caffeine is a plant-derived alkaloid that is generally known as a central nervous system (CNS) stimulant. In order to examine the effects of caffeine on higher CNS functions in insects, we used an appetitive olfactory learning paradigm for the cricket Gryllus bimaculatus. Crickets can form significant long-term memories (LTMs) after repetitive training sessions, during which they associate a conditioned stimulus (CS: odor) with an unconditioned stimulus (US: reward). Administration of hemolymphal injections of caffeine established LTM after only single-trial conditioning over a wide range of caffeine dosages (1...
October 2016: Zoological Science
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