Regulation of Protein Dynamics in Heart Failure

 描述（由申请人提供）：在心力衰竭（HF）之前的心脏重塑期间，多种生物分子（例如，核酸和蛋白质）同时向新的稳定状态转变，因为心脏经历细胞状态的大量和渐进变化。系统技术现在允许同时测量多个生物分子的分子谱，但由于mRNA和蛋白质丰度之间的相关性较差，结果往往难以解释，部分原因是蛋白质分子的合成和降解速率未被考虑在内。我们小组最近的研究结果表明，心脏重塑的特点是广泛的蛋白质周转动力学的重塑，特别是在核蛋白。蛋白质周转率与表型变化密切相关，同时与蛋白质丰度基本正交，这表明它是我们理解心脏重塑生物学调节的一个缺失维度。 我们推测，一类迄今未探索的疾病驱动因素存在于心脏核中，其由于蛋白水解受损而导致的周转减少驱动心脏重塑的致病过程。为了验证这一假设，我们设计了三个具体目标。目标1将利用我们最近开发的技术平台来测量RNA丰度，蛋白质丰度和蛋白质周转率。我们将寻找候选蛋白驱动程序，表现出降低/不变的mRNA表达，降低/不变的蛋白质周转，但增加的丰度，表明受损的蛋白质水解。此外，我们将（i）利用系统遗传模型对比对心脏重塑（异丙肾上腺素激发）的良好表征模型敏感与耐药的小鼠品系;（ii）优先考虑异丙肾上腺素停药后逆转重塑期间恢复的分子特征。目的2将通过检测它们的蛋白水解机制和体外对蛋白酶体降解的敏感性来验证候选驱动程序。目的3将使用体外模型和在人类NYHA IV级HF患者和具有LVAD介导的反向重构的HF患者中验证疾病蛋白，以确保发现的蛋白驱动因子与预防相关。我们希望这些实验能够阐明蛋白水解在心脏重塑和疾病易感性中的作用。

 DESCRIPTION (provided by applicant): During the cardiac remodeling that precedes heart failure (HF), multiple biomolecules (e.g., nucleic acids and proteins) are simultaneously shifting towards new steady state as the heart undergoes massive and progression changes in cell state. Systems technology now allows the molecular profiles of multiple biomolecules to be simultaneously measured, but results are often difficult to interpret due to the poor correlation between mRNA and protein abundance, in part because the synthesis and degradation rates of protein molecules are unaccounted for. Recent findings from our group suggest that cardiac remodeling is characterized by widespread remodeling in protein turnover dynamics, especially in nuclear proteins. Protein turnover rate correlates well with phenotypic changes whilst being largely orthogonal from protein abundance, highlighting that it is a missing dimension to our understanding of biological regulation of cardiac remodeling. We postulate that a class of heretofore unexplored disease drivers exists in the cardiac nuclei whose decreased turnover due to impaired proteolysis drives the pathogenic process of cardiac remodeling. To test this hypothesis, we designed three specific aims. Aim 1 will utilize a technological platform we recently developed to measure RNA abundance, protein abundance, and protein turnover in combination in vivo. We will search for candidate protein drivers that exhibit decreased/unchanged mRNA expression, decreased/unchanged protein turnover, but increased abundance, suggesting impaired proteolysis. Furthermore, we will (i) utilize a systems genetic model to contrast mouse strains that are susceptible vs. resistant to a well-characterized model of cardiac remodeling (isoproterenol challenge); and (ii) prioritize molecular features that are restored during reverse remodeling following isoproterenol withdrawal. Aim 2 will validate the candidate drivers by examining their mechanism of proteolysis and susceptibility to proteasomal degradation in vitro. Aim 3 will validate the disease proteins using in vitro models and in human NYHA Class IV HF patients and HF patients with LVAD-mediated reverse remodeling to ensure the discovered protein drivers are translationally relevant. We expect the experiments to shed light on the role of proteolysis in cardiac remodeling and disease susceptibility.