Lipid regulation of Cardiac Excitation-Contraction coupling

心脏兴奋-收缩耦合的脂质调节

基本信息

批准号：
10451117
负责人：
Rose Ellen Dixon
金额：
$ 60.23万
依托单位：
UNIVERSITY OF CALIFORNIA AT DAVIS
依托单位国家：
美国
项目类别：
财政年份：
2022
资助国家：
美国
起止时间：
2022-06-01 至 2026-05-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10451117
关键词：
Actins Acute Address Adult Angiotensin II Arachidonic Acids Architecture Area Biochemistry Biological Assay Biomechanics Biotinylation Bypass Calcium Cardiac Cardiac Output Cell Death Cell membrane Cell surface Cells Chronic Consensus Coupled Coupling Cyclic AMP-Dependent Protein Kinases Data Dimerization Electrophysiology (science)Electrostatics Endocytosis Equilibrium Excision F-Actin Functional disorder Gene Expression Goals Health Heart failure Hydrolysis Hypertension Hypertrophy Image Infusion procedures Ion Channel Knowledge Ligation Link Lipids Mass Spectrum Analysis Mediating Membrane Microtubules Modeling Mus Muscle Cells Myocardial Nanostructures Nocodazole Optics Output PTEN gene Pathologic Perfusion Phosphatidylinositol 4,5-Diphosphate Phosphatidylinositols Phospholipase C Phospholipids Phosphoric Monoester Hydrolases Phosphorylation Physiological Play Production Regulation Resolution Role RyR2 Sarcolemma Signal Pathway Signal Transduction Sirolimus Stress Structure Surface System Techniques Testing Vasoconstrictor Agents Ventricular actin capping protein blood pressure control blood pressure regulation calmodulin-dependent protein kinase II cardioprotection experimental study heart function imaging approach improved in silico innovation latrunculin A novel patch clamp prevent receptor recruit response theories tool trafficking

项目摘要

Project Summary Experiments outlined in this application, suggest a novel paradigm, that acute angiotensin II (AngII)-stimulated PIP2 hydrolysis triggers cardiac CaV1.2 channel internalization, providing a means to rapidly tune cellular excitability and modulate EC-coupling in health. In contrast, we propose that sustained deficits in plasma membrane CaV1.2 expression, and PIP2 depletion during chronic AngII can trigger a maladaptive compensatory sympathetic response that improves cardiac function in the short-term but ultimately leads to progressive, pathological cardiac remodeling, hypertrophy, and potentially arrhythmogenic Ca2+ signaling dysregulation. We provide compelling preliminary data indicating that PIP2 hydrolysis, downstream of acute AngII/AT1R/Gq activation, leads to endocytosis of cardiac CaV1.2 channels. We can visualize this endocytosis occurring dynamically in live ventricular myocytes upon perfusion with physiological concentrations of AngII (100 nM). Initial results indicate a shift in the balance between channel insertion and removal, such that AngII-stimulated removal of PM channels, leads to an ~30 % reduction in PM CaV1.2 abundance. We observe a strikingly similar %-reduction in three other separate experimental approaches, finding decreased ICa in electrophysiology studies, reduced channel cluster area and expression in super-resolution imaging, and a loss of PM CaV1.2 in surface biotinylation. We isolate PIP2 as the critical executor of this response, distinct from the activation of PKC and arachidonic acid production that accompanies AT1R stimulation with experiments that bypass the receptors and instead utilize a rapamycin-stimulated dimerization system to recruit a 4’,5’ phosphatase to the membrane and deplete PIP2. Our results support a novel mechanistic role of PIP2 on Cav1.2 channel trafficking and expression which can be tuned in response to physiological signaling cascades to modulate EC-coupling during acute regulation of blood pressure. We further propose that chronic depletion of PIP2 during AngII/AT1R signaling associated with heart failure causes: (i) sustained destabilization of PM CaV1.2 and long-lived expression deficits; (ii) a compensatory sympathetic response to boost cardiac function involving activation of PKA and CaMKII that acts in combination with direct AT1R-stimulated CaMKII to enhance CaV1.2 and RyR2 phosphorylation, producing enhanced Po and diastolic leak that stimulates CaN/NFAT and hypertrophic gene expression; (iii) enhanced IP3 production that also stimulates CaN/NFAT and hypertrophic gene expression, and (iv) cytoskeletal instability as a result of depletion of cardioprotective PI(3,4,5)P3 and enhanced ROS-induced microtubule catastrophe that disrupts channel delivery and promotes biomechanical instability, t-tubule and loss of dyads. We propose to rigorously test these ideas in two specific aims described herein.

项目概要本申请中概述的实验提出了一种新的范例，即急性血管紧张素 II (AngII) 刺激 PIP2 水解触发心脏 CaV1.2 通道内化，提供快速调节细胞的方法相比之下，我们建议血浆中的持续缺陷。慢性 AngII 期间膜 CaV1.2 表达和 PIP2 耗竭可引发适应不良代偿交感神经反应可以在短期内改善心脏功能，但最终会导致进行性、病理性心脏重塑、肥厚和潜在致心律失常的 Ca2+ 信号传导失调。提供了令人信服的初步数据，表明 PIP2 水解是急性 AngII/AT1R/Gq 的下游激活，导致心脏 CaV1.2 通道的内吞作用我们可以想象这种内吞作用的发生。在灌注生理浓度的 AngII (100 nM) 后，活心室肌细胞中的动态变化。初步结果表明通道插入和移除之间的平衡发生了变化，使得 AngII 刺激去除 PM 通道，导致 PM CaV1.2 丰度减少约 30%，我们观察到惊人相似的情况。 %-其他三种单独实验方法的减少，在电生理学研究中发现 ICa 减少，超分辨率成像中通道簇面积和表达减少，表面 PM CaV1.2 丢失我们将 PIP2 分离为该反应的关键执行者，与 PKC 和 PKC 的激活不同。通过绕过受体的实验，伴随 AT1R 刺激产生花生四烯酸相反，利用雷帕霉素刺激的二聚化系统将 4',5' 磷酸酶募集到膜上，我们的结果支持 PIP2 对 Cav1.2 通道运输和表达的新机制作用。它可以根据生理信号级联进行调整，以在急性发作期间调节 EC 耦合我们进一步提出 AngII/AT1R 信号转导过程中 PIP2 的慢性消耗。与心力衰竭原因相关：(i) PM CaV1.2 持续不稳定和长期表达缺陷； (ii) 代偿性交感神经反应，以促进 PKA 和 CaMKII 的心脏功能激活，涉及与直接 AT1R 刺激的 CaMKII 联合作用，增强 CaV1.2 和 RyR2 磷酸化，产生增强的 Po 和舒张期渗漏，刺激 CaN/NFAT 和肥大基因表达；增强的 IP3 产生也刺激 CaN/NFAT 和肥大基因表达，以及 (iv) 细胞骨架由于心脏保护作用的 PI(3,4,5)P3 耗尽和 ROS 诱导的微管增强而导致不稳定破坏通道传递并促进生物力学不稳定、T 管和二元体损失的灾难。我们建议在本文描述的两个具体目标中严格测试这些想法。