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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：
10219035
负责人：
TingTing Hong
金额：
$ 38.13万
依托单位：
UNIVERSITY OF UTAH
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 2022-04-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10219035
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.

项目总结/摘要在心室肌细胞中，横小管（T-小管）浓缩L-型钙离子在肌浆中与ryanodine受体（RyR 2）接近并形成二联体的LTCC通道网状膜。二分体是如何形成的还不很清楚。本报告的总体目标应用是识别健康和衰竭心脏中二分体组织的关键组成部分。我中心假设是膜变形蛋白BIN 1在T细胞内产生微区，微管微折叠，组织LTCC簇并募集RyR 2受体以形成适当的二分体，促进同步的钙诱导的钙释放和限制心律失常。此外，BIN 1 已知在获得性心力衰竭中减少，当这些BIN 1-组织微区被破坏。所提出的研究的基本原理是，基于BIN 1的二分体结构和功能的调节受损是心力衰竭进展的可逆方面。三个目标中的第一个是确定在生理正常的心肌细胞中，心脏BIN 1如何负责组织LTCC-RyR 2二联体。在初步数据的基础上，小鼠（有或没有Bin 1缺失）和人类心肌细胞，我们将使用超分辨率荧光成像，以确定LTCC-RyR 2在BIN 1诱导的微结构域的定位，并测试其作用。肌动蛋白细胞骨架在LTCC-RyR 2复合物的形成和功能。第二个目标是确定 BIN 1依赖性微区在心力衰竭中如何被破坏。根据初步数据，我们将使用心力衰竭的人类和小鼠模型来定量BIN 1剪接和同种型表达，肾小管折叠，LTCC-RyR 2复合物的形成和功能，以及外源性BIN 1。我们还将研究Bin 1转录减少和异常表达的机制是否与细胞凋亡有关。心力衰竭中的剪接是由于β-肾上腺素能交感神经失调。第三个目标是确定 β-肾上腺素能阻滞剂是否能挽救BIN 1微区并限制心律失常和心力衰竭发展在初步数据的基础上，我们将研究Bin 1缺失的小鼠是否会发生紧张时会出现心律失常和心力衰竭，这可以通过β-肾上腺素能阻滞来挽救。我们在这里的贡献预计是详细了解如何BIN 1诱导LTCC- RyR 2微结构域在正常和患病的心脏中都有组织和调节。这一贡献是重要的，因为它将确定一种新的方法来改善心力衰竭的进展，保留对正常心脏功能至关重要的BIN 1微区。拟议的研究是创新，在我们看来，因为它引入了相对未知的BIN 1作为T的决定因素，从而帮助调节心脏二联体和钙瞬变。