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

• 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
• 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

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.

项目摘要/摘要 在心室肌细胞中，横管(T管)浓缩L型钙离子 与Ryanodine受体(RyR2)在肌浆接近并形成二联体的通道(LTCC) 网状膜。我们还不能很好地理解这两个二分体是如何形成的。这样做的总体目标是 应用是在健康和衰竭的心脏中识别二联体组织的关键成分。我的 中心假说是，膜变形蛋白BIN1在T- 小管微折叠，组织LTCC簇和招募RyR2受体以形成适当的二联体， 促进钙诱导的同步钙释放，限制心律失常。此外，BIN1 已知在获得性心力衰竭中会减少，当这些BIN1组织起来时，可能会导致心力衰竭 微域被破坏了。这项拟议研究的基础是，基于BIN1的 二联体结构和功能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，是否和 心脏BIN1如何负责组织LTCC-RyR2二联体。以成人初步数据为基础 小鼠(有或没有BIN1缺失)和人心肌细胞，我们将使用超分辨 荧光成像识别LTCC-RyR2在BIN1诱导的微区的定位，并测试其作用 肌动蛋白细胞骨架在LTCC-RyR2复合体的形成和功能。第二个目标是确定 BIN1依赖微域在心力衰竭中是如何被破坏的。根据初步数据，我们将 使用人类和小鼠心力衰竭模型来量化BIN1的剪接和异构体表达，T- 小管折叠，LTCC-RyR2复合体的形成和功能，以及LTCC-RyR2的挽救能力 外源BIN1。我们还将研究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调节失调。第三个目标是确定 -肾上腺素能受体阻滞剂能否挽救BIN1微区，限制心律失常和心力衰竭 发展。在初步数据的基础上，我们将调查BIN1缺失的小鼠是否会发生 应激时的心律失常和心力衰竭，可以通过-肾上腺素能受体阻滞剂来挽救。 我们在这里的贡献将是详细了解BIN1如何诱导LTCC- RyR2微域在正常和疾病心脏中都有组织和调节。这一贡献 意义重大，因为它将确定一种新的方法，通过以下方式改善心力衰竭的进展 保护对正常心脏功能至关重要的BIN1微域。拟议的研究是 创新，在我们看来，因为它引入了相对未知的BIN1作为T-1的决定因素 因此，微管微域有助于调节心脏二联体和钙瞬变。