Molecular mechanisms of the development of cardiomyopathies caused by mutations in desmosomal proteins

致心律失常性右室心肌病（ARVC）是一种遗传性疾病，可导致长期心力衰竭，并常导致心源性猝死。分子遗传学研究表明，编码桥粒蛋白的基因突变是导致该病的主要原因。最近，我们发现约35%的ARVC患者在基因（相应蛋白）DSG 2（桥粒芯糖蛋白2）、PKP 2（斑嗜蛋白2）、DSP（桥粒斑蛋白）和DSC 2（桥粒胶原蛋白2）中携带序列变体。我们还发现，DES基因突变可以导致ARVC的表型。DES突变导致ARVC的分子机制还很不清楚，本项目的目的是：a）与ARVC相关的DES突变的病理生物化学和纳米生物物理性质的相关性及其对心肌中间丝细胞骨架稳定性和完整性的影响，以及桥斑蛋白I介导的桥粒细胞粘附。实验将集中在原子力显微镜、结蛋白细丝的单分子力光谱。B）分析结蛋白变体的细胞毒性特性及其被蛋白酶体或自噬体/溶酶体降解，c）计划将结蛋白相互作用实验扩展到细胞间桥粒系统，并进行第一次纳米力学实验（AFM力光谱以及具有光镊的单细胞测定）用于研究在ARVC患者中鉴定的桥粒芯糖蛋白-2变体的相互作用性质。

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a hereditary disease leading to ter-minal heart failure and frequently to sudden cardiac death. Molecular genetics revealed that mutations in genes coding for desomsomal proteins are predominately responsible for this dis-ease. Recently, we showed that about 35% of ARVC patients carry sequence variants in the genes (corresponding proteins) DSG2 (desmoglein 2), PKP2 (plakophilin 2), DSP (desmoplakin) and DSC2 (desmocollin 2). We also revealed, that a mutation in the gene DES can cause the phenotype of ARVC. The molecular mechanisms of DES-mutations leading to ARVC are vastly not known.The aims of this project are thereforea) The correlation of pathobiochemical and nanobiophysical properties of DES-mutations asso-ciated with ARVC and their consequences on stability and integrity of the myocardial intermediate filament cytoskeleton and the desmsomal cell adhesion mediated by desmoplakin I. The experiments will focus on atomic force microscopy, single molecule force spectroscopy of desmin filaments.b) The analysis of cytotoxic properties of desmin variants and their degradation by the proteasome or autophagosome/lysosome, respectively.c) It is planned to extend the desmin interaction experiments to intercellular desmosomal systems and perform first nanomechanical experiments (AFM force spectroscopy as well as a single-cell assay with optical tweezers) for investigating the interaction properties of desmoglein-2 variants identified in patients with ARVC.