Novel SIRT5 Enzymatic Activity Regulates Cellular Mechanisms of Aging and Disease

描述（由申请人提供）：目前关于衰老的研究主要集中在与年龄相关疾病的分子机制上，线粒体功能障碍与几种人类衰老疾病有关。然而，线粒体功能障碍的细胞机制以及它们如何导致与年龄相关的疾病尚不清楚。线粒体蛋白的化学修饰控制着线粒体功能的几个方面，本项目的长期目标是了解这些修饰是如何由NAD（+）依赖性sirtuin脱乙酰酶调节的，并影响衰老疾病。本提案的目的是确定SIRT5在衰老的分子机制中的作用。核心假设是SIRT5通过从线粒体蛋白中去除新发现的酰基修饰来调节线粒体功能。在SIRT5缺失的情况下，线粒体蛋白将变得高度酰化，线粒体功能降低，并表现出一些加速衰老的标志。这一假设的基本原理是基于初步数据，这些数据表明SIRT5在衰老和疾病的细胞机制中发挥重要作用。为了验证这些假设，将追求三个具体目标：1。确定蛋白质酰化作为年龄函数的变化，使用蛋白质组学策略量化来自年轻，中年和老年小鼠的肝脏线粒体蛋白酰化；2. 通过结合细胞和小鼠模型，确定这种新型酰基修饰对蛋白质功能的影响，以测量特定蛋白质的蛋白质活性变化，以及整体功能

DESCRIPTION (provided by applicant): Current research on aging has largely focused the molecular mechanisms of age-related diseases, and mitochondrial dysfunction has been associated with several human diseases of aging. However, the cellular mechanisms of mitochondrial dysfunction and how they lead to age-related diseases are not known. Chemical modifications to mitochondrial proteins control several aspects of mitochondrial function, and the long-term goal of this project is to understand how these modifications are regulated by the NAD(+)-dependent sirtuin deacylases and influence the diseases of aging. The objective of this proposal is to define the role of SIRT5 in the molecular mechanisms of aging. The central hypothesis is that SIRT5 regulates mitochondrial function by removing a newly discovered acyl modification from mitochondrial proteins. In the absence of SIRT5, mitochondrial proteins will become hyper-acylated, have reduced mitochondrial function, and exhibit several markers of accelerated aging. The rationale for this hypothesis is based on preliminary data, which suggests an important role for SIRT5 in the cellular mechanisms of aging and disease. To test these hypotheses, three specific aims will be pursued: 1. Determine the changes in protein acylation as a function of age, using a proteomic strategy to quantify hepatic mitochondrial protein acylation from young, middle-aged, and old mice; 2. Determine the effect of this novel acyl modification on protein function by using a combination of cell and murine models, in order to measure the changes in protein activity of specific proteins, as well as the overall function of mitochondria; 3. Determine role of SIRT5 on aging by measuring several physiological parameters of aging using both in vitro cellular assays and in vivo assays in mice, to determine how SIRT5 maintains mitochondrial and cellular homeostasis during aging. This study combines a novel protein modification, a comprehensive experimental design, and an innovative conceptual framework. Furthermore, this study will build a foundation for this early-stage investigator and ensure a successful research program focused on the cellular mechanisms of aging and disease. Importantly, the proposed research is significant because it is expected to advance and expand understanding how mitochondrial dysfunction can lead to age-related diseases. Ultimately such knowledge has the potential to inform the development of new therapies against several diseases of aging.