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("ryanodine receptor" OR "ryr" OR "ryr2") AND ("heart" OR "cardiac")

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https://www.readbyqxmd.com/read/29150445/the-antiapoptotic-protein-hax-1-mediates-half-of-phospholamban-s-inhibitory-activity-on-calcium-cycling-and-contractility-in-the-heart
#1
Philip A Bidwell, Kobra Haghighi, Evangelia G Kranias
The antiapoptotic protein HS-associated protein X-1 (HAX-1) localizes to sarcoplasmic reticulum (SR) in the heart and interacts with the small membrane protein phospholamban (PLN), inhibiting the cardiac sarco/endoplasmic reticulum calcium ATPase (SERCA2a) in the regulation of overall calcium handling and heart muscle contractility. However, because global HAX-1 deletion causes early lethality, how much endogenous HAX-1 contributes to PLN's inhibitory activity on calcium cycling is unknown. We therefore generated a cardiac-specific and inducible knockout mouse model...
November 17, 2017: Journal of Biological Chemistry
https://www.readbyqxmd.com/read/29150444/toll-like-receptor-4-induced-ryanodine-receptor-2-oxidation-and-sarcoplasmic-reticulum-ca2-leakage-promote-cardiac-contractile-dysfunction-in-sepsis
#2
Jie Yang, Rui Zhang, Xin Jiang, Jingzhang Lv, Ying Li, Hongyu Ye, Wenjuan Liu, Gang Wang, Cuicui Zhang, Na Zheng, Ming Dong, Yan Wang, Peiya Chen, Kumar Santosh, Yong Jiang, Jie Liu
Studies suggest the potential role of sarcoplasmic reticulum (SR) Ca2+ leak in cardiac contractile dysfunction in sepsis. However, direct supporting evidence is lacking, and the mechanisms underlying this SR leak are poorly understood. Here, we investigated the changes in cardiac Ca2+ handling and contraction in LPS-treated rat cardiomyocytes and a mouse model of polymicrobial sepsis produced by cecal ligation and puncture (CLP). LPS decreased the systolic Ca2+ transient and myocyte contraction, as well as SR Ca2+ content...
November 17, 2017: Journal of Biological Chemistry
https://www.readbyqxmd.com/read/29145393/estimating-the-probabilities-of-rare-arrhythmic-events-in-multiscale-computational-models-of-cardiac-cells-and-tissue
#3
Mark A Walker, Viatcheslav Gurev, John J Rice, Joseph L Greenstein, Raimond L Winslow
Ectopic heartbeats can trigger reentrant arrhythmias, leading to ventricular fibrillation and sudden cardiac death. Such events have been attributed to perturbed Ca2+ handling in cardiac myocytes leading to spontaneous Ca2+ release and delayed afterdepolarizations (DADs). However, the ways in which perturbation of specific molecular mechanisms alters the probability of ectopic beats is not understood. We present a multiscale model of cardiac tissue incorporating a biophysically detailed three-dimensional model of the ventricular myocyte...
November 2017: PLoS Computational Biology
https://www.readbyqxmd.com/read/29132927/whole-exome-sequencing-identified-a-pathogenic-mutation-in-ryr2-in-a-chinese-family-with-unexplained-sudden-death
#4
Yubi Lin, Siqi He, Zili Liao, Ruiling Feng, Ruilin Liu, Yongzheng Peng, Nan Yu, Hang Qi, Jia Chen, Zifeng Huang, Heping Lei, Yang Liu, Fang Rao, Chunyu Deng, Yumei Xue, Guolin Zhang, Bin Zhang, Hua Yao, Shulin Wu
OBJECTIVE: This study aimed to identify the pathogenic mutation in a Chinese family with unexplained sudden death (USD) or occasional syncope. MATERIALS AND METHODS: Whole exome sequencing and target capture sequencing were respectively conducted for two related patients. The genetic data was screened using the 1000 genomes project and SNP database (PubMed), and the identified mutations were assessed for predicted pathogenicity using the SIFT and Polyphen-2 algorithms...
October 10, 2017: Journal of Electrocardiology
https://www.readbyqxmd.com/read/29122978/the-structural-basis-of-ryanodine-receptor-ion-channel-function
#5
REVIEW
Gerhard Meissner
Large-conductance Ca(2+) release channels known as ryanodine receptors (RyRs) mediate the release of Ca(2+) from an intracellular membrane compartment, the endo/sarcoplasmic reticulum. There are three mammalian RyR isoforms: RyR1 is present in skeletal muscle; RyR2 is in heart muscle; and RyR3 is expressed at low levels in many tissues including brain, smooth muscle, and slow-twitch skeletal muscle. RyRs form large protein complexes comprising four 560-kD RyR subunits, four ∼12-kD FK506-binding proteins, and various accessory proteins including calmodulin, protein kinases, and protein phosphatases...
November 9, 2017: Journal of General Physiology
https://www.readbyqxmd.com/read/29097735/mammalian-%C3%AE-2-ampk-regulates-intrinsic-heart-rate
#6
Arash Yavari, Mohamed Bellahcene, Annalisa Bucchi, Syevda Sirenko, Katalin Pinter, Neil Herring, Julia J Jung, Kirill V Tarasov, Emily J Sharpe, Markus Wolfien, Gabor Czibik, Violetta Steeples, Sahar Ghaffari, Chinh Nguyen, Alexander Stockenhuber, Joshua R St Clair, Christian Rimmbach, Yosuke Okamoto, Dongmei Yang, Mingyi Wang, Bruce D Ziman, Jack M Moen, Daniel R Riordon, Christopher Ramirez, Manuel Paina, Joonho Lee, Jing Zhang, Ismayil Ahmet, Michael G Matt, Yelena S Tarasova, Dilair Baban, Natasha Sahgal, Helen Lockstone, Rathi Puliyadi, Joseph de Bono, Owen M Siggs, John Gomes, Hannah Muskett, Mahon L Maguire, Youlia Beglov, Matthew Kelly, Pedro P N Dos Santos, Nicola J Bright, Angela Woods, Katja Gehmlich, Henrik Isackson, Gillian Douglas, David J P Ferguson, Jürgen E Schneider, Andrew Tinker, Olaf Wolkenhauer, Keith M Channon, Richard J Cornall, Eduardo B Sternick, David J Paterson, Charles S Redwood, David Carling, Catherine Proenza, Robert David, Mirko Baruscotti, Dario DiFrancesco, Edward G Lakatta, Hugh Watkins, Houman Ashrafian
AMPK is a conserved serine/threonine kinase whose activity maintains cellular energy homeostasis. Eukaryotic AMPK exists as αβγ complexes, whose regulatory γ subunit confers energy sensor function by binding adenine nucleotides. Humans bearing activating mutations in the γ2 subunit exhibit a phenotype including unexplained slowing of heart rate (bradycardia). Here, we show that γ2 AMPK activation downregulates fundamental sinoatrial cell pacemaker mechanisms to lower heart rate, including sarcolemmal hyperpolarization-activated current (I f) and ryanodine receptor-derived diastolic local subsarcolemmal Ca(2+) release...
November 2, 2017: Nature Communications
https://www.readbyqxmd.com/read/29097503/ryanodine-channel-complex-stabilizer-compound-s48168-arm210-as-a-disease-modifier-in-dystrophin-deficient-mdx-mice-proof-of-concept-study-and-independent-validation-of-efficacy
#7
Roberta Francesca Capogrosso, Paola Mantuano, Kitipong Uaesoontrachoon, Anna Cozzoli, Arcangela Giustino, Todd Dow, Sadish Srinivassane, Marina Filipovic, Christina Bell, Jack Vandermeulen, Ada Maria Massari, Michela De Bellis, Elena Conte, Sabata Pierno, Giulia Maria Camerino, Antonella Liantonio, Kanneboyina Nagaraju, Annamaria De Luca
Muscle fibers lacking dystrophin undergo a long-term alteration of Ca(2+) homeostasis, partially caused by a leaky Ca(2+) release ryanodine (RyR) channel. S48168/ARM210, an RyR calcium release channel stabilizer (a Rycal compound), is expected to enhance the rebinding of calstabin to the RyR channel complex and possibly alleviate the pathologic Ca(2+) leakage in dystrophin-deficient skeletal and cardiac muscle. This study systematically investigated the effect of S48168/ARM210 on the phenotype of mdx mice by means of a first proof-of-concept, short (4 wk), phase 1 treatment, followed by a 12 wk treatment (phase 2) performed in parallel by 2 independent laboratories...
November 2, 2017: FASEB Journal: Official Publication of the Federation of American Societies for Experimental Biology
https://www.readbyqxmd.com/read/29071820/application-of-multigene-panel-sequencing-in-patients-with-prolonged-rate-corrected-qt-interval-and-no-pathogenic-variants-detected-in-kcnq1-kcnh2-and-scn5a
#8
Soo Hyun Seo, So Yeon Kim, Sung Im Cho, Hyunwoong Park, Seungjun Lee, Jong Moon Choi, Man Jin Kim, Jee Soo Lee, Kyung Jin Ahn, Mi Kyoung Song, Eun Jung Bae, Sung Sup Park, Moon Woo Seong
Long QT syndrome (LQTS) is an inherited cardiac disease characterized by a prolonged heart rate-corrected QT (QTc) interval. We investigated the genetic causes in patients with prolonged QTc intervals who were negative for pathogenic variants in three major LQTS-related genes (KCNQ1, KCNH2, and SCN5A). Molecular genetic testing was performed using a panel including 13 LQTS-related genes and 67 additional genes implicated in other cardiac diseases. Overall, putative genetic causes of prolonged QTc interval were identified in three of the 30 patients (10%)...
January 2018: Annals of Laboratory Medicine
https://www.readbyqxmd.com/read/29042943/suxiao-jiuxin-pill-protects-cardiomyocytes-against-mitochondrial-injury-and-alters-gene-expression-during-ischemic-injury
#9
Xiaofen Ruan, Tiejun Chen, Xiaolong Wang, Yiping Li
Suxiao Jiuxin Pill (SX), a traditional Chinese medicine compound consisting primarily of tetramethylpyrazine and borneol, has been reported to protect against ischemic heart disease. However, the effects of SX on mitochondrial injury and gene expression in various signaling pathways are unclear. The aim of the present study was to investigate the effects of SX on mitochondrial injury and to screen the expression of genes potentially altered by SX using a cell culture model of ischemic injury. Simulated ischemia was established by culturing HL-1 cardiomyocytes in Dulbecco's modified Eagle medium without glucose or serum in a hypoxic chamber containing 95% N2 and 5% CO2 for 24 h...
October 2017: Experimental and Therapeutic Medicine
https://www.readbyqxmd.com/read/29037982/early-effects-of-epac-depend-on-the-fine-tuning-of-the-sarcoplasmic-reticulum-ca-2-handling-in-cardiomyocytes
#10
N Lezcano, J I E Mariángelo, L Vittone, X H T Wehrens, M Said, C Mundiña-Weilenmann
In cardiac muscle, signaling through cAMP governs many fundamental cellular functions, including contractility, relaxation and automatism. cAMP cascade leads to the activation of the classic protein kinase A but also to the stimulation of the recently discovered exchange protein directly activated by cAMP (Epac). The role of Epac in the regulation of intracellular Ca(2+) homeostasis and contractility in cardiac myocytes is still matter of debate. In this study we showed that the selective Epac activator, 8-(4-chloro-phenylthio)-2'-O-methyladenosine-3', 5'-cyclic monophosphate (8-CPT), produced a positive inotropic effect when adult rat cardiac myocytes were stabilized at low [Ca(2+)]o (0...
October 14, 2017: Journal of Molecular and Cellular Cardiology
https://www.readbyqxmd.com/read/29037160/-homozygous-and-compound-heterozygous-mutation-in-3-turkish-family-with-jervell-and-lange-nielsen-syndrome-case-reports
#11
Fahrettin Uysal, Burcu Turkgenc, Guven Toksoy, Ozlem M Bostan, Elif Evke, Oya Uyguner, Cengiz Yakicier, Hulya Kayserili, Ergun Cil, Sehime G Temel
BACKGROUND: Jervell and Lange-Nielsen syndrome (JLNS) isa recessive model of long QT syndrome which might also be related to possible hearing loss. Although the syndrome has been demonstrated to be originated from homozygous or compound heterozygous mutations in either the KCNQ1 or KCNE1 genes, additional mutations in other genetic loci should be considered, particularly in malignant course patients. CASE PRESENTATIONS: Three patients were admitted into hospital due to recurrent seizures/syncope, intrauterine and postnatal bradycardia respectively; moreover all three patients had congenital sensorineural hearing-loss...
October 16, 2017: BMC Medical Genetics
https://www.readbyqxmd.com/read/29032884/the-genetics-underlying-idiopathic-ventricular-fibrillation-a-special-role-for-catecholaminergic-polymorphic-ventricular-tachycardia
#12
Jaakko T Leinonen, Lia Crotti, Aurora Djupsjöbacka, Silvia Castelletti, Nella Junna, Alice Ghidoni, Annukka M Tuiskula, Carla Spazzolini, Federica Dagradi, Matti Viitasalo, Kimmo Kontula, Maria-Christina Kotta, Elisabeth Widén, Heikki Swan, Peter J Schwartz
BACKGROUND: Ventricular fibrillation (VF) is a major cause of sudden cardiac death. In some cases clinical investigations fail to identify the underlying cause and the event is classified as idiopathic (IVF). Since mutations in arrhythmia-associated genes frequently determine arrhythmia susceptibility, screening for disease-predisposing variants could improve IVF diagnostics. METHODS AND RESULTS: The study included 76 Finnish and Italian patients with a mean age of 31...
October 5, 2017: International Journal of Cardiology
https://www.readbyqxmd.com/read/29032102/regulation-of-ca-2-signaling-by-acute-hypoxia-and-acidosis-in-rat-neonatal-cardiomyocytes
#13
José-Carlos Fernández-Morales, Martin Morad
Ischemic heart disease is an arrhythmogenic condition, accompanied by hypoxia, acidosis, and impaired Ca(2+) signaling. Here we report on effects of acute hypoxia and acidification in rat neonatal cardiomyocytes cultures. RESULTS: Two populations of neonatal cardiomyocyte were identified based on inactivation kinetics of L-type ICa: rapidly-inactivating ICa (τ~20ms) myocytes (prevalent in 3-4-day cultures), and slow-inactivating ICa (τ≥40ms) myocytes (dominant in 7-day cultures). Acute hypoxia (pO2<5mmHg for 50-100s) suppressed ICa reversibly in both cell-types to different extent and with different kinetics...
October 12, 2017: Journal of Molecular and Cellular Cardiology
https://www.readbyqxmd.com/read/29030236/long-term-aerobic-exercise-in-calsequestrin2-knockout-mice-accentuates-vagal-antagonism-during-%C3%AE-adrenergic-stimulation-which-restricts-heart-rate-acceleration-and-paradoxically-increases-abnormal-ryanodine-receptor-calcium-leak-in-ventricular-myocytes
#14
Hsiang-Ting Ho, Senthil Thambidorai, Björn C Knollmann, George E Billman, Sandor Györke, Anuradha Kalyanasundaram
BACKGROUND: Long-term aerobic exercise alters autonomic balance, which may not be favorable in heart rate (HR)-dependent arrhythmic diseases including catecholaminergic polymorphic ventricular tachycardia (CPVT) because of preexisting bradycardia and increased sensitivity to parasympathetic stimulation. OBJECTIVE: The purpose of this study was to determine whether long-term exercise-induced autonomic adaptations modify CPVT susceptibility. METHODS: We determined exercise-induced parasympathetic effects on HR, arrhythmia incidence, and intracellular sarcoplasmic reticulum (SR) Ca(2+) leak in atrial (ACM) and ventricular (VCM) cardiomyocytes, in exercised (EX) calsequestrin knockout (CASQ2(-/-)) mice, a model of CPVT...
October 10, 2017: Heart Rhythm: the Official Journal of the Heart Rhythm Society
https://www.readbyqxmd.com/read/29029794/rho-kinase-inhibition-reverses-impaired-ca-2-handling-and-associated-left-ventricular-dysfunction-in-pressure-overload-induced-cardiac-hypertrophy
#15
Yusuf Olgar, Murat Cenk Celen, Bilge Eren Yamasan, Nihal Ozturk, Belma Turan, Semir Ozdemir
Recent studies have implicated a relationship between RhoA/ROCK activity and defective Ca(2+) homeostasis in hypertrophic hearts. This study investigated molecular mechanism underlying ROCK inhibition-mediated cardioprotection against pressure overload-induced cardiac hypertrophy, with a focus on Ca(2+) homeostasis. Cardiac hypertrophy model was established by performing transverse aortic constriction (TAC) in 8-week-old male rats. Groups were assigned as SHAM, TAC and TAC+Fas (rats undergoing TAC and treated with fasudil)...
November 2017: Cell Calcium
https://www.readbyqxmd.com/read/29029787/early-testosterone-replacement-attenuates-intracellular-calcium-dyshomeostasis-in-the-heart-of-testosterone-deprived-male-rats
#16
Punate Weerateerangkul, Krekwit Shinlapawittayatorn, Siripong Palee, Nattayaporn Apaijai, Siriporn C Chattipakorn, Nipon Chattipakorn
BACKGROUND: Testosterone deficiency in elderly men increases the risk of cardiovascular disease. In bilateral orchiectomized (ORX) animals, impaired cardiac Ca(2+) regulation was observed, and this impairment could be improved by testosterone replacement, indicating the important role of testosterone in cardiac Ca(2+) regulation. However, the temporal changes of Ca(2+) dyshomeostasis in testosterone-deprived conditions are unclear. Moreover, the effects of early vs. late testosterone replacement are unknown...
November 2017: Cell Calcium
https://www.readbyqxmd.com/read/29027245/epac-induced-ryanodine-receptor-type-2-activation-inhibits-sodium-currents-in-atrial-and-ventricular-murine-cardiomyocytes
#17
Haseeb Valli, Shiraz Ahmad, Sujan Sriharan, Lydia D Dean, Andrew A Grace, Kamalan Jeevaratnam, Hugh R Matthews, Christopher L-H Huang
Acute RyR2 activation by exchange protein directly activated by cAMP (Epac) reversibly perturbs myocyte Ca(2+) homeostasis, slows myocardial action potential conduction, and exerts pro-arrhythmic effects. Loose patch-clamp studies, preserving in vivo extracellular and intracellular conditions, investigated Na(+) current in intact cardiomyocytes in murine atrial and ventricular preparations following Epac activation. Depolarising steps to varying test voltages activated typical voltage-dependent Na(+) currents...
October 12, 2017: Clinical and Experimental Pharmacology & Physiology
https://www.readbyqxmd.com/read/28988521/the-cardioprotective-effect-of-rosmarinic-acid-on-acute-myocardial-infarction-and-genes-involved-in-ca-2-homeostasis
#18
Somayeh Javidanpour, Mahin Dianat, Mohammad Badavi, Seyyed Ali Mard
Acute myocardial infarction (AMI) is a common cause of hospitalisation and high mortality due to lethal arrhythmias. Sarcoplasmic reticulum Ca(2+) ATPase (SERCA2) and ryanodine receptor (RyR2) regulate the cytosolic Ca(2+) ion concentration. Rosmarinic acid (RA) is one of the most common caffeic esters in Rosmarinus officinalis. The present study was conducted to test the hypothesis whether RA can protect cardiac function against AMI and arrhythmias induced by isoproterenol through the regulatory effect of SERCA2 and RyR2 gene expression...
November 3, 2017: Free Radical Research
https://www.readbyqxmd.com/read/28974554/thyroid-and-glucocorticoid-hormones-promote-functional-t-tubule-development-in-human-induced-pluripotent-stem-cell-derived-cardiomyocytes
#19
Shan S Parikh, Daniel J Blackwell, Nieves Gomez-Hurtado, Michael Frisk, Lili Wang, Kyungsoo Kim, Christen P Dahl, Arnt E Fiane, Theis Tønnessen, Dmytro O Kryshtal, William E Louch, Bjorn C Knollmann
Rationale: Human induced pluripotent stem cell derived cardiomyocytes (hiPSC-CM) are increasingly being used for modeling heart disease and are under development for regeneration of the injured heart. However, incomplete structural and functional maturation of hiPSC-CM including lack of t-tubules, immature excitation-contraction (EC) coupling, and inefficient Ca-induced Ca release (CICR) remain major limitations. Objective: Thyroid and glucocorticoid hormones are critical for heart maturation. We hypothesized that their addition to standard protocols would promote t-tubule development and mature EC coupling of hiPSC-CM when cultured on extracellular matrix with physiological stiffness (Matrigel mattress)...
October 2, 2017: Circulation Research
https://www.readbyqxmd.com/read/28964152/minimal-model-for-calcium-alternans-due-to-sr-release-refractoriness
#20
Inma R Cantalapiedra, Enrique Alvarez-Lacalle, Angelina Peñaranda, Blas Echebarria
In the heart, rapid pacing rates may induce alternations in the strength of cardiac contraction, termed pulsus alternans. Often, this is due to an instability in the dynamics of the intracellular calcium concentration, whose transients become larger and smaller at consecutive beats. This alternation has been linked experimentally and theoretically to two different mechanisms: an instability due to (1) a strong dependence of calcium release on sarcoplasmic reticulum (SR) load, together with a slow calcium reuptake into the SR or (2) to SR release refractoriness, due to a slow recovery of the ryanodine receptors (RyR2) from inactivation...
September 2017: Chaos
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