Molecular basis of Ca2+ leak in heart

心脏Ca2漏的分子基础

基本信息

批准号：
8461982
负责人：
George S. B. Williams
金额：
$ 5.83万
依托单位：
UNIVERSITY OF MARYLAND BALTIMORE
依托单位国家：
美国
项目类别：
财政年份：
2011
资助国家：
美国
起止时间：
2011-05-16 至 2014-05-15
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8461982
关键词：
A Mouse Accounting Action Potentials Address Affect Arrhythmia Behavior Biological C57BL/6 Mouse Ca(2+)-Transporting ATPase Calcium Cardiac Cell model Cell physiology Cells Characteristics Computer Simulation Coupling Data Development Disease model Drug Formulations Endoplasmic Reticulum Environment Equilibrium Event Foundations Frequencies Functional disorder Future Goals Heart Heart Diseases Heart failure Image Investigation Ions L-Type Calcium Channels Location Measurement Membrane Mentors Methods Modeling Molecular Movement Mus Muscle Cells Mutant Strains Mice Mutation Organelles Pathway interactions Physiological Play Process Property Pump Qualifying Research Rest Role RyR2 Ryanodine Receptor Calcium Release Channel Ryanodine Receptors Sarcolemma Sarcoplasmic Reticulum Series Signal Transduction Site Study models Techniques Testing Ventricular Ventricular Tachycardia Work base heart cell heart function insight mathematical model mutant novel novel therapeutics patch clamp research study simulation skills success tool uptake

项目摘要

DESCRIPTION (provided by applicant): The cellular and subcellular movement of calcium (Ca2+) in heart cells underlies cellular contraction and influences electrical behavior. The PI and his co-mentors have recently discovered new features of Ca2+ movement in heart cells that have profound implications for understanding heart function. Here, the PI proposes to investigate the novel discovery of "invisible Ca2+ leak" by combining quantitative mathematical investigations with experimental tests. Ca2+ leak is the loss of Ca2+ from intracellular storage organelles and plays a vital role in maintaining healthy cellular Ca2+ content by balancing uptake from the sarco/endoplasmic reticulum Ca2+ ATPase (SERCA) pump. Understanding Ca2+ leak and its molecular basis is essential for experimental and theoretical examination of cellular physiology, pathophysiology (including heart failure and arrhythmias), and developing new therapeutics. The planned investigation of SR Ca2+ leak will exploit novel and very efficient mathematical tools recently invented by the PI and his co-mentors that will enable a fully stochastic mathematical investigation of the Ca2+ signaling in single cardiac ventricular myocytes. Work by the PI and his co-mentors has provided preliminary mathematical and biological characterization of two components of Ca2+ leak: Ca2+ sparks (see introduction) and "invisible," non-spark Ca2+ leak. These two components appear to play a role in both normal and arrhythmogenic Ca2+ signaling behavior but have yet to be characterized at the molecular level. The proposed work will test this critical Ca2+ signaling behavior by combining mathematical modeling investigations with single mouse ventricular myocyte experiments. Confocal Ca2+ imaging with simultaneous patch clamp experiments will be carried out in enzymatically dissociated cells to inform the modeling and test the findings. Ca2+ sparks, [Ca2+]i transients, and membrane currents will be investigated in myocytes from control mice (C57BL/6) and from mutant mice with specific alterations in the cardiac ryanodine receptor (RyR2) (C57BL/6- R2474S) that produce Ca2+-dependent arrhythmias (see [1]). Preliminary work by the PI and his co-mentors suggest that there are profound differences in the Ca2+ leak characteristics in the control and mutant heart cells. The proposed investigation into SR Ca2+ leak in heart seeks to address two critically important questions on cardiac Ca2+ signaling: 1) What is the molecular mechanism of SR Ca2+ leak in healthy myocytes? and 2) how do arrhythmogenic RyR2 mutations affect SR Ca2+ leak? The unique feature of the proposed work is the combination of modeling and experiments in a richly interactive environment with a strong record of success in such work. For the PI, the investigation nicely supports his long-term plan to combine theoretical investigations with practical and informative tests with the prospect of broadening our understanding of cardiac cellular function.

描述（由申请人提供）：心脏细胞中钙（Ca2+）的细胞和亚细胞运动是细胞收缩的基础并影响电行为的。 PI及其联合给者最近发现了心脏细胞中Ca2+运动的新特征，这些特征对理解心脏功能具有深远的影响。在这里，PI建议通过将定量数学研究与实验测试相结合，研究“无形CA2+泄漏”的新发现。 Ca2+泄漏是细胞内存储细胞器中Ca2+的损失，并且通过平衡来自Sarco/sarco/内质网Ca2+ ATPase（SERCA）泵的吸收来维持健康的细胞Ca2+含量至关重要。了解Ca2+泄漏及其分子基础对于细胞生理学，病理生理学（包括心力衰竭和心律不齐）的实验和理论检查以及开发新的治疗剂至关重要。对SR CA2+泄漏的计划研究将利用PI及其同事最近发明的新颖和非常有效的数学工具，该工具将对单个心脏心室心肌细胞中Ca2+信号传导进行完全随机的数学研究。 PI及其联合给出者的工作提供了Ca2+泄漏的两个组成部分的初步数学和生物学表征：Ca2+ Sparks（请参阅简介）和“无形”，Non-Spark Ca2+泄漏。这两个成分似乎在正常和心律失常Ca2+信号传导行为中起作用，但尚未在分子水平上进行表征。提出的工作将通过将数学建模研究与单小鼠心室心肌细胞实验相结合，来测试这种关键的CA2+信号传导行为。共聚焦Ca2+与同时的斑块夹实验将在酶联分离的细胞中进行，以告知建模并测试发现。 Ca2+火花，[Ca2+] I瞬变和膜电流将在对照小鼠（C57BL/6）和突变小鼠的肌细胞中进行研究，并在心脏ryanodine受体（RyR2）（RyR2）（C57BL/6- R2474S）中具有特异性改变，这些变化产生Ca2+依赖性二级值的ca2+二元。 PI及其联合学者的初步工作表明，对照和突变心细胞的Ca2+泄漏特征存在深远的差异。对心脏中SR CA2+泄漏的拟议研究旨在解决有关心脏CA2+信号传导的两个至关重要的问题：1）健康心肌细胞中SR Ca2+泄漏的分子机制是什么？ 2）心律失常RYR2突变如何影响SR Ca2+泄漏？拟议工作的独特特征是在丰富的互动环境中结合建模和实验，并在此类工作中取得了成功的记录。对于PI，调查很好地支持了他的长期计划，将理论研究与实用和信息性测试结合在一起，并扩大我们对心脏细胞功能的理解的前景。