Beta-1 Integrin and Caveolin-3 in Cardiac Mechanotransduction

Beta-1 整合素和 Caveolin-3 在心脏机械转导中的作用

• 批准号: 8698324
• 负责人: Robert Scott Ross
• 金额: --
• 依托单位: VA SAN DIEGO HEALTHCARE SYSTEM
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-04-01 至 2014-04-05
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8698324
• 关键词: Actins; Adhesives; Adult; Ambulatory Care; Area; Attention; Cardiac; Cardiac Myocytes; Cardiomyopathies; Caveolae; Caveolins; Cell membrane; Cell physiology; Cell surface; Cells; Cytoskeleton; Data; Disease; Endocytosis; Environment; Extracellular Matrix; Failure; Family; Focal Adhesions; Functional disorder; Grant; Heart; Heart Diseases; Heart failure; Hospitalization; Hypertension; Immunoprecipitation; Integrins; Investigation; Knock-out; Knockout Mice; Lead; Link; Mechanics; Membrane; Mus; Muscle Cells; Muscle function; Mutation; Myocardium; Myopathy; Patients; Plant Roots; Play; Positioning Attribute; Prevalence; Process; Property; Protein Family; Proteins; Public Health; Receptor Signaling; Role; Shapes; Signal Transduction; Signaling Molecule; Stress; Structure; Testing; Transgenic Mice; Veterans; Work; base; caveolin-3; clinically significant; flasks; gain of function; improved; lipid metabolism; member; mouse model; novel; novel therapeutics; overexpression; prevent; protein expression; protein function; receptor; research study; response; skeletal

DESCRIPTION (provided by applicant): A commonality of many of the diseases which lead to heart failure is a derangement in normal mechanosensing by the cardiac muscle cell. Despite extensive investigation, the precise mechanisms by which the cardiomyocyte senses mechanical changes, transmits these changes into the cell, and alters myocyte function, is poorly understood. Further, how the heart is maintained in a compensated state despite mechanical challenges, and what alters this state and transitions the myocardium towards failure, is not known. Two areas of the cardiomyocyte that appear critical for proper mechanotransduction are the costamere and caveolae. Key proteins of these areas are the integrins and caveolins. Integrins are a large family of cell- surface adhesive receptors that are also signaling molecules in virtually all cells. Caveolae are flask-shaped invaginations in the plasma membrane of cells, including cardiac myocytes. These structures have been linked to numerous cellular functions including endocytosis, establishment of a signaling microdomain and lipid metabolism. Caveolin protein expression has been found essential for caveolae formation. Importantly, mutations in members of both these families have been linked to skeletal and cardiac myopathies. Our preliminary data show that b1 and Caveolin-3 co-localize in the adult myocyte and that these proteins interact with each, as shown by immunoprecipitation experiments. Importantly, we have produced mice which can be used for loss and gain of function approaches to assess the role of these proteins in the myocyte, and whole heart. These include b1 cardiac-specific knockout (KO) (b1cKO) and Caveolin-3KO, as well as transgenic mice in which various integrin subunits and Caveolin-3 expression are increased in a cardiac myocyte specific manner. Using these mouse models we have also shown that in the Caveolin-3KO, costameric localization of b1 integrin is lost and that its distribution in cellular sub-fractions is altered. Likewise in the b1cKO, the sub-cellular arrangement of Caveolin-3 is changed. Further, loss of b1 integrin as well as Caveolin-3 from the cardiac myocyte can ultimately lead to heart failure. In contrast, we have begun to show that increased expression of these proteins in myocytes can protect. Based on this data, the overall hypothesis for this proposal is that: b1 integrins and caveolin-3 have cooperative properties as mechanotransducers and membrane stabilizing proteins in the cardiac myocyte. A corollary that follows from this is that together, these proteins will have important roles in the process of cardiac adaptations to mechanical load and may modify how the heart transitions from a compensated state towards heart failure. To investigate this, 3 aims are proposed: 1) Determine the cooperative roles of b1 integrins and caveolin-3 in mechanotransductive responses of the myocardium by use of Caveolin-3 null and b1 integrin cardiac myocyte specific knockout mice alone or in combination. 2) Define the interactions which direct cooperative mechanical signaling of cardiomyocyte beta-1 integrin and caveolin-3. 3) Determine how single or dual overexpression of caveolin-3 and/ or ab1 integrins alters mechanical responses, and delays or protects from cardiac failure in the face of hypertrophic induction using mouse models. Clinical Significance: Heart failure of varied causes is found in a large number of VA patients, necessitating frequent hospitalizations and attention to outpatient care. Identification of root causes of cardiac dysfunction and importantly, studies which could lead to novel therapeutics of this common disease, are essential, and will be the focus of this proposal.

描述（由申请人提供）： 许多导致心力衰竭的疾病的共同点是心肌细胞正常机械感觉的紊乱。尽管进行了广泛的研究，但人们对心肌细胞感知机械变化、将这些变化传递到细胞中以及改变心肌细胞功能的精确机制知之甚少。此外，尽管存在机械挑战，心脏如何保持在代偿状态，以及是什么改变了这种状态并使心肌转变为衰竭，尚不清楚。心肌细胞中对于适当的机械转导至关重要的两个区域是肋节和小凹。这些区域的关键蛋白质是整合素和小窝蛋白。整合素是细胞表面粘附受体的一大家族，实际上也是所有细胞中的信号分子。小凹是细胞（包括心肌细胞）质膜中的烧瓶状内陷。这些结构与许多细胞功能相关，包括胞吞作用、信号微结构域的建立和脂质代谢。已发现小窝蛋白表达对于小窝形成至关重要。重要的是，这两个家族成员的突变都与骨骼肌病和心肌病有关。我们的初步数据表明，b1 和 Caveolin-3 在成体肌细胞中共定位，并且这些蛋白质彼此相互作用，如免疫沉淀实验所示。重要的是，我们已经培育出可用于功能丧失和获得方法的小鼠，以评估这些蛋白质在肌细胞和整个心脏中的作用。这些包括 b1 心脏特异性敲除 (KO) (b1cKO) 和 Caveolin-3KO，以及转基因小鼠，其中各种整合素亚基和 Caveolin-3 表达以心肌细胞特异性方式增加。使用这些小鼠模型，我们还表明，在 Caveolin-3KO 中，b1 整联蛋白的肋侧定位丢失，并且其在细胞亚组分中的分布发生改变。同样，在 b1cKO 中，Caveolin-3 的亚细胞排列也发生了变化。此外，心肌细胞中 b1 整合素和 Caveolin-3 的丢失最终会导致心力衰竭。相反，我们已经开始证明，增加这些蛋白质在肌细胞中的表达可以起到保护作用。基于这些数据，该提议的总体假设是：b1 整合素和 Caveolin-3 具有作为心肌细胞中的机械传感器和膜稳定蛋白的协同特性。由此得出的推论是，这些蛋白质一起将在心脏适应机械负荷的过程中发挥重要作用，并可能改变心脏从代偿状态向心力衰竭转变的方式。为了研究这一点，提出了 3 个目标： 1) 通过单独或组合使用 Caveolin-3 null 和 b1 整合素心肌细胞特异性敲除小鼠，确定 b1 整合素和 Caveolin-3 在心肌机械传导反应中的协同作用。 2) 定义指导心肌细胞β-1整合素和caveolin-3协同机械信号传导的相互作用。 3) 使用小鼠模型确定caveolin-3和/或ab1整合素的单一或双重过度表达如何改变机械反应，并在面对肥厚诱导时延迟或预防心力衰竭。临床意义：大量 VA 患者存在各种原因的心力衰竭，需要经常住院并注意门诊治疗。确定心脏功能障碍的根本原因，重要的是，研究可能导致这种常见疾病的新疗法是至关重要的，也将成为该提案的重点。