Regulation of Ion Channels at BIN1-induced T-tubule Microdomains

BIN1 诱导的 T 管微区离子通道的调节

基本信息

批准号：
9921467
负责人：
TingTing Hong
金额：
$ 5.63万
依托单位：
CEDARS-SINAI MEDICAL CENTER
依托单位国家：
美国
项目类别：
财政年份：
2016
资助国家：
美国
起止时间：
2016-07-01 至 2020-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9921467
关键词：
Actins Adrenergic Agents Adult Affect Alternative Splicing American Arrhythmia Biochemical Biological Calcium Cardiac Cardiac Myocytes Cells Chronic Complex Coupling Cytoskeleton Data Development Diffusion Epidemic F-Actin Genetic Transcription Goals Heart Heart Diseases Heart failure Human Image Impairment Infusion procedures Ion Channel Ions Isoproterenol L Forms L-Type Calcium Channels Medical Membrane Membrane Microdomains Methods Mission Modeling Molecular Mus Organ Outcome Pathologic Pathway interactions Physiological Positioning Attribute Predisposition Protein Isoforms Proteins Public Health RNA Splicing Regulation Research Resolution Role Ryanodine Receptors Sarcoplasmic Reticulum Signal Transduction Stress Structure Surface Syndrome Testing Therapeutic Intervention United States United States National Institutes of Health Ventricular Work base extracellular fluorescence imaging heart function human model innovation mouse model new therapeutic target novel strategies preservation receptor receptor coupling recruit

项目摘要

PROJECT SUMMARY/ABSTRACT In ventricular cardiomyocytes, transverse-tubules (T-tubules) concentrate L-type calcium channels (LTCC) which approximate and form dyads with ryanodine receptors (RyR2) at sarcoplasmic reticulum membrane. It is not well understood how the dyads form. The overall objective of this application is to identify the key components of dyad organization in healthy and failing hearts. My central hypothesis is that the membrane deformation protein BIN1 creates microdomains within T- tubule microfolds, organizing LTCC clusters and recruiting RyR2 receptors for proper dyad formation, facilitating synchronized calcium-induced-calcium-release and limiting arrhythmias. Furthermore, BIN1 is known to decrease in acquired heart failure, and heart failure can result when these BIN1-orgnized microdomains are disrupted. The rationale that underlies the proposed research is that BIN1-based impaired regulation of dyad structure and function is a reversible aspect of heart failure progression. The first of three aims is to determine, in physiologically normal cardiomyocytes, whether and how cardiac BIN1 is responsible for organizing LTCC-RyR2 dyads. Building on preliminary data, in adult mouse (with or without Bin1 deletion) and human cardiomyocytes, we will use super-resolution fluorescent imaging to identify LTCC-RyR2 localization at BIN1-induced microdomains, and test the role of actin cytoskeleton in LTCC-RyR2 complex formation and function. The second aim is to determine how BIN1 dependent microdomains are disrupted in heart failure. Building on preliminary data, we will use human and mouse models of heart failure to quantify BIN1 splicing and isoform expression, T- tubule folds, and LTCC-RyR2 complex formation and function, as well as the rescue ability of exogenous BIN1. We will also study whether the mechanism of reduced Bin1 transcription and aberrant splicing in heart failure is due to -adrenergic sympathetic dysregulation. The third aim is to determine whether -adrenergic blockade can rescue BIN1-microdomains and limit arrhythmias and heart failure development. Building on preliminary data, we will investigate whether Bin1 deleted mice develop arrhythmia and heart failure when stressed, which can be rescued by -adrenergic blockade. Our contribution here is expected to be a detailed understanding of how BIN1-induced LTCC- RyR2 microdomains are organized and regulated in both normal and diseased hearts. This contribution is significant because it will identify a new approach to ameliorate heart failure progression by preserving the BIN1 microdomains that are critical to normal heart function. The proposed research is innovative, in our opinion, because it introduces the relatively unknown BIN1 as a determinant of T- tubule microdomains thus helping regulate cardiac dyads and calcium transients.

项目概要/摘要在心室心肌细胞中，横管（T 管）集中 L 型钙通道（LTCC）与肌浆中的兰尼碱受体（RyR2）接近并形成二元体网状膜的总体目标尚不清楚。应用程序是确定健康和衰竭心脏中二元组织的关键组成部分。中心假设是膜变形蛋白 BIN1 在 T- 肾小管微折叠，组织 LTCC 簇并招募 RyR2 受体以形成正确的二元体，促进同步钙诱导的钙释放并限制心律失常。已知可减少获得性心力衰竭，当这些 BIN1 组织时，可能会导致心力衰竭所提出的研究的基本原理是基于 BIN1 的。对二元结构和功能的调节受损是心力衰竭进展的一个可逆方面。三个目标中的第一个是确定在生理正常的心肌细胞中是否和基于成人的初步数据，心脏 BIN1 如何负责组织 LTCC-RyR2 成对体。小鼠（有或没有 Bin1 删除）和人类心肌细胞，我们将使用超分辨率荧光成像识别 LTCC-RyR2 在 BIN1 诱导的微域中的定位，并测试其作用第二个目的是确定肌动蛋白细胞骨架在 LTCC-RyR2 复合物形成和功能中的作用。基于初步数据，我们将了解 BIN1 依赖性微结构域如何在心力衰竭中受到破坏。使用人类和小鼠心力衰竭模型来量化 BIN1 剪接和亚型表达，T- 肾小管折叠、LTCC-RyR2 复合物的形成和功能，以及救援能力我们还将研究外源性BIN1转录减少和异常的机制。心力衰竭中的剪接是由于  肾上腺素能交感神经失调引起的。第三个目的是确定。 -肾上腺素能阻断是否可以挽救 BIN1-微区并限制心律失常和心力衰竭根据初步数据，我们将调查 Bin1 缺失的小鼠是否发育。应激时出现心律失常和心力衰竭，可通过 β-肾上腺素能阻断来挽救。我们在这里的贡献预计是详细了解 BIN1 诱导的 LTCC- RyR2 微结构域在正常心脏和患病心脏中均受到组织和调节。意义重大，因为它将确定一种改善心力衰竭进展的新方法保留对正常心脏功能至关重要的 BIN1 微结构域。我们认为这是创新的，因为它引入了相对未知的 BIN1 作为 T- 的决定因素肾小管微区，从而帮助调节心脏二元体和钙瞬变。