SD COBRE: UBIQUITIN-PROTEASOME IN CARDIAC REMODELING AND FAILURE

这个子项目是利用由NIH/NCRR资助的中心拨款提供的资源的许多研究子项目之一。子项目和调查员(PI)可能从另一个NIH来源获得了主要资金，因此可能会出现在其他CRISE条目中。列出的机构是针对中心的，而不一定是针对调查员的机构。这项建议的一个长期目标是描述蛋白过剩心肌病(PSCs)进展为充血性心力衰竭的机制。PSCs是一组新兴的心肌病。由α-晶状体蛋白(CryAB)基因突变引起的结晶病，通常表现为结蛋白相关性心肌病(DRC)，是PSCs的典型代表。DRC的特点是在肌肉细胞中出现异常的结蛋白聚集，这种聚集似乎在DRC的发病机制中起着中心作用。值得注意的是，在由特发性扩张型心肌病引起的人类充血性心力衰竭(CHF)中也观察到了类似的蛋白质聚集体，这是一种常见的心脏病。然而，目前尚不清楚蛋白质的异常聚集如何影响心肌细胞的功能。目前的建议集中在泛素-蛋白酶体系统(UPS)介导的蛋白质周转，这是一个几乎对细胞功能的所有方面都至关重要的细胞过程。中心假说是DRC的异常蛋白聚集特性损害了UPS的蛋白分解功能，代表了PSCs的一个结节致病过程。这些特定的目标将被追求：(1)测试CryAB是否在UPS功能中具有强制性作用，并确定完整小鼠中异常的蛋白质聚集与UPS损伤之间的相关性(可能是因果关系)。潜在的假设是，晶体病变心脏中异常的蛋白质聚集而不是功能丧失的CryAB会损害UPS。(2)检测细胞培养中蛋白质聚集异常与UPS损伤之间的因果关系。这是为了验证这样一种假设，即通过表达突变的CryAB来形成蛋白质聚集体足以损害UPS功能。(3)利用蛋白质组学方法对晶体病小鼠心脏组织中泛素化蛋白进行鉴定。潜在的假设是，累积的泛素化蛋白包括结构蛋白和重要的生理调节蛋白。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. A long term goal of this proposal is to delineate the mechanisms by which protein surplus cardiomyopathies (PSCs) progress to congestive heart failure. PSCs are an emerging group of cardiomyopathies. Crystallinopathy caused by the mutation of the alphaB-crystallin (CryAB) gene, often presents as desmin-related cardiomyopathy (DRC) and exemplifies PSCs. DRC is characterized by aberrant desmin aggregation in muscle cells and this aggregation appears to play a central role in DRC pathogenesis. Notably, similar protein aggregates were also observed in human congestive heart failure (CHF) resulting from idiopathic dilated cardiomyopathy, a common heart disease. However, it remains unclear how abnormal protein aggregation affects myocyte functions. The current proposal focuses on the ubiquitin-proteasome system (UPS) mediated protein turnover, a cellular process essential to virtually all aspects of cell function. The central hypothesis is that aberrant protein aggregation characteristic of DRC impairs proteolytic function of the UPS, representing a nodal pathogenic process in PSCs. These specific aims will be pursued: (1) To test whether CryAB has an obligatory role in UPS function and to define a correlation (likely a causal relation) between aberrant protein aggregation arid UPS impairment in intact mice. The underlying hypothesis is that aberrant protein aggregation instead of loss-of-function of CryAB impairs the UPS in crystallinopathic hearts. (2) To test a cause-effect link between aberrant protein aggregation and UPS impairment in cell culture. This is to test the hypothesis that formation of protein aggregates through expression of a mutant CryAB is sufficient to compromise UPS function. (3) To discover the identities of ubiquitylated proteins accumulated in crystallinopathy mouse hearts using proteomics. Underlying hypothesis is that accumulated ubiquitylated proteins include structural proteins and physiologically important regulatory proteins.