Beta-arrestin Signaling and Sarcomere Calcium-Response in Familial Dilated Cardiomyopathy

家族性扩张型心肌病中的β-抑制蛋白信号传导和肌节钙反应

• 批准号: 9330917
• 负责人: David M Ryba
• 金额: $ 2.57万
• 依托单位: UNIVERSITY OF ILLINOIS AT CHICAGO
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-09-30 至 2018-05-15
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9330917
• 关键词: Affect; Aftercare; Angiotensin II; Angiotensin Receptor; Animals; Area; Biochemical; Calcium; Cardiac; Characteristics; Chronic; Clinical Data; Complex; Coupled; Detergents; Development; Dilated Cardiomyopathy; Disease Progression; Echocardiography; Fiber; Functional disorder; G-substrate; GTP-Binding Proteins; Goals; Grant; Heart; Heart Transplantation; Heart failure; Histologic; Human; Hypertension; Hypertrophy; In Vitro; Investigation; Kinetics; Left Ventricular Function; Ligands; Link; Losartan; Measurement; Measures; Mediating; Methods; Microfilaments; Microscopic; Microscopy; Missense Mutation; Molecular; Morphology; Mus; Patients; Pharmacology; Phenotype; Phosphoric Monoester Hydrolases; Phosphorylation; Phosphotransferases; Post-Translational Protein Processing; Preventive Intervention; Proteins; Proteome; Proteomics; Receptor, Angiotensin, Type 1; Reporting; Rest; Saline; Sarcomeres; Signal Pathway; Signal Transduction; Signal Transduction Pathway; Signaling Molecule; Skin; Text; Therapeutic Intervention; Transgenic Mice; Transgenic Model; Tropomyosin; Work; beta-arrestin; blood pump; experimental study; familial dilated cardiomyopathy; heart cell; heart function; hemodynamics; improved; improved functioning; in vivo; infancy; insight; mouse model; mutant; novel; pre-clinical; prevent; public health relevance; response; scaffold; success; targeted treatment

 DESCRIPTION (provided by applicant): Familial dilated cardiomyopathy (DCM) is a condition that leads to heart failure and is the most common cause of heart transplantation. The molecular mechanisms of disease progression are not well characterized, and there are no current therapies available for this condition. A characteristic molecular change in DCM is decreased myofilament response to Ca2+. Thus, we hypothesized that by increasing the myofilament response to Ca2+ we may be able to prevent the development of DCM. As proof of principle, we crossed a transgenic model with a missense mutation on sarcomeric protein, tropomyosin (TG-Tm-E54K), which displays a phenotype similar to human DCM, with a transgenic mouse characterized by a constitutive increase in Ca2+-sensitivity. In these double transgenic mice, DCM does not develop. Results from our preliminary studies indicate that novel beta-arrestin signaling pathways are directly involved in signaling to myofilaments, imparting Ca2+-sensitizing post-translational modification, and improving heart function. In this proposal, we hypothesize that beta-arrestin signaling prevents the progression of and reverses DCM by improving the Ca2+ responsiveness of the myofilament. Our approach is to employ TG-TmE54K mice and treat them with the biased ligand, TRV120023, which acts as an angiotensin receptor blocker but is able to activate beta-arrestin signaling, or Losartan, an angiotensin receptor blocker. In Specific Aim 1 we will evaluate the progression of the disease before, during and after treatment in vivo utilizing serial echocardiography. We will also assess left ventricular function in vivo and morphology using hemodynamic studies and histological methods, respectively. To approach Specific Aim 2, we will employ detergent extracted fiber bundles to measure steady-state force and kinetics of treated animals and saline controls. We will also determine the mechanism behind these changes using biochemical methods where we will elucidate the signal transduction pathways activated. In Specific Aim 3 we will use biochemical methods and microscopy to examine beta-arrestin localization to fully characterize these novel signal transduction pathways. We expect that activation of beta-arrestin signaling, while blocking G- protein mediated signaling, will prevent the progression of and reverse DCM by increasing Ca2+-responsiveness of the myofilament. Therefore, results from this proposal will yield pre-clinical data for a potential treatment for DCM, as well as insight into the molecular mechanisms of heart failure.

 描述（由申请人提供）：家族性扩张型心肌病（DCM）是一种导致心力衰竭的疾病，也是心脏移植的最常见原因。疾病进展的分子机制尚未得到很好的表征，并且目前没有可用的治疗方法。 DCM 的一个特征性分子变化是减少肌丝对 Ca2+ 的反应，因此，我们发现通过增加肌丝对 Ca2+ 的反应，我们可以预防 DCM 的发生。我们将具有肌节蛋白原肌球蛋白 (TG-Tm-E54K) 错义突变的转基因模型原理与具有与人类 DCM 相似的表型的转基因小鼠进行交叉，该转基因小鼠的特征是 Ca2+ 敏感性持续增加。我们的初步研究结果表明，新的β-抑制蛋白信号通路直接参与向肌丝的信号传导，从而赋予转基因小鼠DCM。 Ca2+ 敏化翻译后修饰并改善心脏功能 在本提案中，我们研究了 β-arrestin 信号传导通过改善肌丝的 Ca2+ 反应性来预防和逆转 DCM。使用偏向配体 TRV120023 治疗它们，该配体充当血管紧张素受体阻滞剂，但能够激活 β-arrestin 信号传导，或氯沙坦，一种血管紧张素受体阻滞剂。 目标 1，我们将利用超声心动图在体内连续评估疾病的进展，我们还将分别使用血流动力学研究和组织学方法评估左心室功能和形态。使用洗涤剂提取的纤维束来测量经过处理的动物和盐水对照的稳态力和动力学，我们还将使用生化方法确定这些变化背后的机制，并阐明具体激活的信号转导途径。目标 3，我们将使用生化方法和显微镜检查 β-arrestin 定位，以充分表征这些新的信号转导途径。我们预计，β-arrestin 信号传导的激活，在阻断 G 蛋白介导的信号传导的同时，将阻止 DCM 的进展并逆转 DCM。因此，该提案的结果将为 DCM 的潜在治疗提供临床前数据，并深入了解心力衰竭的分子机制。