Investigating the novel role of acetylation in cardiac mitochondrial bioenergetics and function in the aging heart

心脏线粒体功能障碍是衰老和许多年龄相关疾病的发病机制的核心。 线粒体通过氧化燃料为心脏收缩功能提供生物能量 基质和该系统的完全控制对于维持心脏效率是必不可少的。具体地说， 羟酰辅酶A脱氢酶（HADHA）和长链酰辅酶A脱氢酶（LCAD）在 心脏中催化长链脂肪酸氧化的作用已被充分研究， 脂肪酸氧化（FAO）和心脏能量消耗减少。然而，研究集中在 了解调节这些关键线粒体能量底物酶的细胞机制， 衰老的心脏是稀缺的。在最近的一项研究中，我们描述了乙酰化的增加增加了 LCAD和HADHA在饮食诱导的肥胖中的作用，这是由线粒体表达的变化介导的。 乙酰转移酶GCN 5L1和脱乙酰酶SIRT 3。在衰老的心脏中，我们观察到GCN 5L1增加， SIRT3表达降低导致HADHA和LCAD的乙酰化状态增加。基于 根据这些观察，我们假设GCN 5L1和SIRT 3控制HADHA和LCAD乙酰化， 这种机制在衰老中的失调有助于降低线粒体生物能量学， 心肌细胞能量耗竭为了检验我们的中心假设，我们提出了以下目标：1。我们将 探讨乙酰化对青年、中年和老年小鼠HADHA和LCAD活性的调节作用 心中使用基于高分辨率质谱的蛋白质组学，我们将确定乙酰化位点，相对 量化和评估它们在关键生物过程和酶功能中的影响。2.我们将 探讨青年、中年人HADHA和LCAD活性调节的相关机制， 还有老鼠的心脏我们将使用新的GCN 5L1和SIRT 3心脏KO动物来描绘分子水平， 衰老过程中HADHA和LCAD乙酰化变化的潜在机制。3.我们将调查如何 脂肪酸氧化蛋白乙酰化的变化影响线粒体生物能量学和心肌收缩 衰老心脏的功能。这项研究的长期目标是了解心脏的调节作用， 线粒体乙酰化在人类衰老和年龄相关疾病中的作用。我们的研究结果将增进我们对 乙酰化介导的FAO酶在衰老线粒体生物学的调节，并提供新的见解 调节衰老心脏中燃料底物的使用及其对改善线粒体的贡献 和心脏功能。

Cardiac mitochondrial dysfunction is central to the pathogenesis of aging and many age related diseases. Mitochondria supply the bioenergetic capacity for cardiac contractile function through oxidation of fuel substrates and a complete control of this system is indispensable to maintain cardiac efficiency. Specifically, the role of Hydroxyacyl-CoA Dehydrogenase (HADHA) and Long Chain Acyl-CoA Dehydrogenase (LCAD) in catalyzing the oxidation of long chain fatty acids in the heart is well studied and their dysfunction is associated with decreased fatty acid oxidation (FAO) and cardiac energy depletion. However, studies focused on understanding the cellular mechanisms that regulate these key mitochondrial energy substrate enzymes in the aging heart are scarce. In a recent study, we described that increased acetylation increases the activities of LCAD and HADHA in diet induced obesity, which was mediated by changes in the expression of mitochondrial acetyltransferase GCN5L1 and deacetylase SIRT3. In the aging heart, we observe increased GCN5L1 and decreased SIRT3 expression resulting in an increased acetylation status of HADHA and LCAD. Based on these observations, we hypothesize that GCN5L1 and SIRT3 control HADHA and LCAD acetylation, and that dysregulation of this mechanism in aging contributes to reduced mitochondrial bioenergetics and cardiomyocyte energy depletion. To test our central hypothesis, we propose the following aims: 1. We will investigate how acetylation regulates the activity of HADHA and LCAD in young, middle aged and old mouse hearts. Using high resolution mass spectrometry based proteomics; we will identify acetylation sites, relative quantification and assess their impact in key biological processes and enzymatic functions. 2. We will investigate the mechanisms associated with regulation of HADHA and LCAD activity in young, middle aged and old mouse hearts. We will use novel GCN5L1 and SIRT3 cardiac KO animal to delineate the molecular mechanisms underlying changes in HADHA and LCAD acetylation in aging process. 3. We will investigate how changes in fatty acid oxidation protein acetylation impacts mitochondrial bioenergetics and cardiac contractile function in aging heart. The long term goal of this study is to understand the regulatory role of cardiac mitochondrial acetylation in human aging and age related diseases. Our results will improve our understanding of acetylation mediated regulation of FAO enzymes in aging mitochondrial biology and provide novel insights on regulation of fuel substrate usage in the aging heart and their contribution towards improving mitochondrial and cardiac function with age.