Reversal of Hypertrophic Cardiomyopathy via Conditional Ablation of Cardiac Myosin Light Chain Kinase

通过条件性消融心肌肌球蛋白轻链激酶逆转肥厚型心肌病

• 批准号: 9332683
• 负责人: Karissa M Dieseldorff Jones
• 金额: $ 3.59万
• 依托单位: FLORIDA STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-05-05 至 2020-05-04
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9332683
• 关键词: Ablation; Address; Affect; Bioinformatics; Blood; Breeding; Calcium; Cardiac; Cardiac Myocytes; Cardiac Myosins; Cardiac ablation; Cardiac health; Cardiomyopathies; Cardiovascular Diseases; Characteristics; Data; Development; Diagnosis; Dilated Cardiomyopathy; Disease; Disease model; EFRAC; Echocardiography; Elements; Exhibits; Functional disorder; Gene Expression; Gene Expression Regulation; Genes; Genetic; Genetic Crosses; Goals; Growth; Heart; Heart Atrium; Heart Diseases; Histopathology; Homozygote; Human; Hypertension; Hypertrophic Cardiomyopathy; Hypertrophy; Impairment; Individual; Injection of therapeutic agent; Ischemia; Knock-in; Knock-in Mouse; Knock-out; Knockout Mice; Lead; Left Ventricular Hypertrophy; Left ventricular structure; Length; Measurement; Measures; Microfilaments; Molecular; Molecular Profiling; Morphology; Mus; Muscle Cells; Mutation; Myopathy; Myosin Light Chain Kinase; Myosin Regulatory Light Chains; Pathogenicity; Patients; Phenotype; Phosphorylation; Phosphotransferases; Physiology; Play; Process; Property; Proteins; Proteomics; Relaxation; Reporting; Restrictive Cardiomyopathy; Role; Sarcomeres; Structure; Tamoxifen; Testing; Therapeutic; Tissues; Troponin C; Valine; Western Blotting; Work; base; biological systems; disease phenotype; experimental study; genetic approach; heart function; hemodynamics; improved; in utero; insight; mRNA Expression; mouse model; novel; pressure; proband; protein expression; protein profiling; sensor; sudden cardiac death; therapeutic target; tibia; tool; transcriptome sequencing; young adult

Project Summary Hypertrophic cardiomyopathy (HCM), as the leading cause of sudden cardiac death in young adults, affects approximately 1 in 500 individuals and is characterized by diastolic dysfunction, fibrotic tissue formation, impaired contractile properties and, most evidently, left ventricle hypertrophy and increased myofilament Ca2+ sensitivity. To date, there are no effective non-invasive therapies for HCM. Mutations in sarcomeric proteins—including cardiac troponin C (cTnC), the Ca2+ sensor in contraction—seem to be the causative agents in the disease. The disease mechanisms and how the various mutations lead to myopathy, however, are poorly understood. More specifically, the Ala8Val (A8V) mutation in cTnC has been identified among HCM patients and within three independent probands and led us to develop the knock-in mouse model based on its pathogenicity. The A8V mutation in humans and mice causes left ventricular hypertrophy and hypercontractility, atrial enlargement, and increased myofilament Ca2+ sensitivity (the latter only tested in mice). Recently, cardiac myosin light chain kinase (cMLCK) knock-out mice were shown to exhibit reduced ejection fraction. This is attributed to the reduction in regulatory myosin light chain phosphorylation, which is known to decrease myofilament Ca2+ sensitivity. Consequently, we hypothesize that a conditional cMLCK knock-out of a cTnC-A8V (HCM phenotype) mouse can normalize cardiac function toward wild-type. We believe this will improve heart morphology, hemodynamics, and protein expression levels, as measured via ECHO, pressure-volume loops, histopathology, heart to tibia length ratios, cardiomyocyte Ca2+ and twitch transients, and western blots for Ca2+ handling proteins. In addition, we will use advanced bioinformatics tools such as proteomics and RNA sequencing to quantify overall changes in these mouse models. Cardiac myosin light chain kinase has thus far been characterized as a dedicated kinase, making it a promising therapeutic target. As such, the proposed work can set the stage for novel, targeted heart disease therapy for HCM.

项目摘要 肥厚性心肌病(HCM)是导致年轻人心源性猝死的主要原因，其影响 大约每500人中就有1人，其特征是舒张期功能障碍，纤维组织形成，受损 收缩特性，最明显的是左心室肥厚和肌丝对钙的敏感性增加。 到目前为止，还没有有效的非侵入性疗法来治疗肥厚性心肌炎。肌瘤蛋白的突变--包括 心肌肌钙蛋白C(CTNC)，收缩中的钙感受器-似乎是这种疾病的病原体。这个 然而，疾病机制和各种突变如何导致肌病却知之甚少。更多 具体地说，cTNC中的Ala8Val(A8V)突变已在HCM患者中被发现，在三个 独立的先证者，并导致我们开发了基于其致病性的敲入小鼠模型。A8V 人类和小鼠的突变导致左心室肥厚和收缩功能亢进，心房增大，以及 增加肌丝对钙离子的敏感性(后者仅在小鼠身上测试)。最近，心肌肌球蛋白轻链激酶 (CMLCK)基因敲除的小鼠表现出射血分数降低。这归因于减少了 调节肌球蛋白轻链的磷酸化，这是已知的降低肌丝对钙的敏感性。 因此，我们假设cTNC-A8V(HCM表型)小鼠的条件cMLCK基因敲除可以 将心功能正常化为野生型。我们相信这将改善心脏形态，血流动力学， 以及通过回声、压力-体积环、组织病理学、心脏到胫骨测量的蛋白质表达水平 长度比，心肌细胞钙和抽动瞬变，以及钙处理蛋白的蛋白质印迹。此外, 我们将使用先进的生物信息学工具，如蛋白质组学和RNA测序来量化总体变化 在这些小鼠模型中。到目前为止，心肌肌球蛋白轻链激酶一直被表征为一种专用的激酶， 使其成为一个有希望的治疗靶点。因此，拟议的工作可以为新奇的、有针对性的心脏奠定基础 肥厚型心肌炎的疾病治疗。