Mechanism for Regulation of Phospholipase C by G Protein

G蛋白调节磷脂酶C的机制

• 批准号: 8235285
• 负责人: Alan V. Smrcka
• 金额: $ 31.36万
• 依托单位: UNIVERSITY OF ROCHESTER
• 依托单位国家: 美国
• 财政年份: 1996
• 资助国家: 美国
• 起止时间: 1996-09-30 至 2015-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8235285
• 关键词: 1,2-diacylglycerol; A kinase anchoring protein; Ablation; Acute; Address; Adrenergic Receptor; Adult; Affect; Agonist; American; Angiotensin II; Animal Model; Arrhythmia; Binding; Biological Models; Buffers; Calcium; Cardiac; Cardiac Myocytes; Cardiac Output; Cell Fractionation; Cell Nucleus; Cells; Characteristics; Chest; Chronic; Complex; Coupled; Cyclic AMP; Cyclic AMP-Dependent Protein Kinases; DAG/PE-Binding Domain; Data; Development; Diagnosis; Diglycerides; Endothelin-1; Fluorescence Resonance Energy Transfer; Funding; GTP-Binding Proteins; Generations; Genes; Genetic; Goals; Guanosine Triphosphate Phosphohydrolases; Heart; Heart Hypertrophy; Heart failure; Hormones; Hydrolysis; Hypertrophy; Inositol; Insulin-Like Growth Factor I; Isoproterenol; Lead; Measures; Methods; Modeling; Molecular; Mus; Muscle; Muscle Cells; Myosin Heavy Chains; Nature; Neonatal; Nuclear; Nuclear Envelope; Pathogenesis; Pathway interactions; Pharmacological Treatment; Phosphatidylinositol 4,5-Diphosphate; Phosphatidylinositols; Phospholipase C; Physiological; Process; Production; Protein Biosynthesis; Protein Isoforms; Proteins; Publishing; Rattus; Regulation; Regulatory Pathway; Role; RyR2; Ryanodine Receptor Calcium Release Channel; Sarcoplasmic Reticulum; Signal Pathway; Signal Transduction; Signaling Protein; Small Interfering RNA; Specific qualifier value; Stress; Tamoxifen; Ventricular; adenosine cyclic-3' ,5' -monophosphate binding proteins; base; constriction; cost; heart function; imaging modality; inhibitor/antagonist; mutant; novel; novel strategies; receptor; research study; response; rho; scaffold

DESCRIPTION (provided by applicant): Heart failure (HF) affects an estimated 4.7 million Americans, with approximately 550,000 new cases diagnosed annually and estimated annual costs ranging from $10 to $40 billion. One of the characteristics of progression to heart failure is reduced cardiac output due to decreased contractility and cardiac hypertrophy. We have identified a novel a cAMP-dependent pathway, involving the novel cAMP binding protein, Epac, and PLCe that increases cardiac calcium-induced calcium release (CICR) and ionotropic responses to ¿-adrenergic receptor (¿AR) stimulation. This pathway functions in physiological regulation of cardiac function and may also contribute to increased diastolic calcium release that underlies arrhythmogenesis during chronic adrenergic receptor stimulation. We will expand on this published discovery of a new PLCe dependent regulatory pathway in the heart by following new clues from our new exciting preliminary data on the importance of PLCe sub cellular scaffolding and signaling in regulation of both CICR and hypertrophy. The major focus is on I. understanding mechanisms underlying how sub cellular scaffolding of PLC5e may specify contractile vs. hypertrophic signaling, and II. Examining how PLCe can potentially integrate inputs from multiple signaling pathways by virtue of its unique ability to respond to multiple molecular signals. We will achieve these goals by exploring the following hypotheses: 1) Scaffolding to the Type II Ryanodine receptor (RyR2) and muscle A kinase anchoring protein (mAKAP) specifies distinct compartmentation of PLCe in cardiac cells. We found that PLCe forms complexes with both mAKAP and RyR2 in the heart. We hypothesize that mAKAP- and RyR2-complexed PLCe are separately compartmentalized pools in cardiac myocytes involved in regulation of hypertrophy and CICR, respectively. To address this idea we will examine the nature of the scaffold PLCe complexes and determine the roles of these complexes in cardiac function 2) Role of PLCe scaffolding in regulating hypertrophic signaling at the nucleus. We will explore the hypothesis developed in aim 1 that scaffolding PLCe in the heart specifies regulation of distinct functional Ca2+ signals involved in CICR in the SR, and inositol trisphosphate (IP3) dependent Ca2+ signals in the nucleus. We will also examine the role of scaffold PLCe in local diacylglycerol (DAG), PKC and PKD signals at the nucleus. We will also examine how PLCe can integrate multiple upstream signals to regulate these processes. 3) Mechanisms for PLCe- dependent regulation of cardiac hypertrophy. Preliminary data indicate that siRNA-dependent knockdown of PLCe inhibits protein synthesis stimulated by chronic ET-1 and Iso treatment in neonatal rat ventricular myocytes (NRVMs) suggesting PLCe involvement in cardiac hypertrophy, a marker for development of heart failure. We will explore these mechanisms further in a whole animal model system with cardiac myocyte specific deletion of PLCe. PUBLIC HEALTH RELEVANCE: Heart failure (HF) affects an estimated 4.7 million Americans, with approximately 550,000 new cases diagnosed annually and estimated annual costs ranging from $10 to $40 billion. One of the characteristics of progression to heart failure is reduced cardiac output due to decreased contractility and cardiac hypertrophy. The proposed experiments to understand new roles for phospholipase C in the heart will address fundamental mechanisms of heart failure and function that could lead to the development of novel therapies for heart failure.

描述（由申请人提供）：心力衰竭 (HF) 影响估计 470 万美国人，每年诊断出约 550,000 例新病例，估计每年花费 10 至 400 亿美元。进展为心力衰竭的特征之一是心输出量减少。我们发现了一种新的 cAMP 依赖性途径，涉及新的 cAMP 结合蛋白、Epac 和 PLCe，可增加心脏钙诱导的钙释放。 (CICR) 和离子型响应 ¿ -肾上腺素能受体（¿AR）刺激。该途径在心脏功能的生理调节中起作用，并且还可能有助于增加舒张期钙释放，这是慢性肾上腺素能受体刺激期间心律失常发生的基础。通过遵循我们新的令人兴奋的初步数据中的新线索，了解 PLCe 亚细胞支架和信号传导在 CICR 和肥大调节中的重要性，主要重点是 I. 了解其背后的机制。 PLC5e 的亚细胞支架可能会指定收缩信号与肥大信号，并且检查 PLCe 如何利用其响应多种分子信号的独特能力来潜在地输入信号，我们将通过探索以下假设来实现这些目标： 1) II 型 Ryanodine 受体 (RyR2) 和肌肉 A 激酶锚定蛋白 (mAKAP) 的支架指定了心脏细胞中 PLCe 的不同区室。我们发现 mAKAP 和 RyR2 复合的 PLCe 是心肌细胞中分别参与肥厚和 CICR 调节的单独区室。为了解决这个问题，我们将研究支架 PLCe 的性质。复合物并确定这些复合物在心脏功能中的作用 2) PLCe 支架在调节细胞核肥大信号传导中的作用 我们将探讨目标 1 中提出的支架假设。心脏中的 PLCe 指定参与 SR 中 CICR 的不同功能性 Ca2+ 信号以及细胞核中肌醇三磷酸 (IP3) 依赖性 Ca2+ 信号的调节。我们还将研究支架 PLCe 在局部二酰基甘油 (DAG)、PKC 和 PKD 中的作用。我们还将研究 PLCe 如何整合多个上游信号来调节这些过程 3) PLCe 依赖性心脏调节机制。初步数据表明，siRNA 依赖性 PLCe 敲低可抑制新生大鼠心室肌细胞 (NRVM) 中长期 ET-1 和 Iso 治疗刺激的蛋白质合成，表明 PLCe 参与心脏肥大，这是心力衰竭发展的标志。这些机制进一步出现在具有心肌细胞特异性删除 PLCe 的整个动物模型系统中。 公共卫生相关性：心力衰竭 (HF) 影响估计 470 万美国人，每年诊断出约 55 万例新病例，估计每年花费 10 至 400 亿美元。进展为心力衰竭的特征之一是心输出量减少。所提出的旨在了解磷脂酶 C 在心脏中的新作用的实验将解决心力衰竭和功能的基本机制，从而可能导致心力衰竭新疗法的开发。