Project 1

心血管疾病是糖尿病患者死亡的主要原因，在没有其他已知危险因素的情况下可能会发生。线粒体生物能量缺乏和自由基产生增加是糖尿病心肌病(DCM)的病理特征。该项目的一个目标是确定线粒体中发生的导致代谢功能障碍和氧化应激的分子变化。具体地说，我们正在研究失调的线粒体蛋白赖氨酸乙酰化 导致代谢不灵活、线粒体功能障碍和扩张型心肌病的进展。我们的假设是，高血糖导致特定代谢酶(如蛋白激酶A)的病理性蛋白赖氨酸乙酰化增加，从而导致脂肪酸氧化、线粒体功能障碍和氧化应激增加。使用1型糖尿病的转基因啮齿动物模型和细胞培养技术，我们将检验以下假设：目标1.定义发生在 随着糖尿病的进展，导致线粒体功能障碍和氧化应激增加的线粒体。线粒体底物选择、氧化磷酸化和自由基的产生将与心脏结构和功能的变化同时进行分析，使用磁共振成像(MRI)和组织学。目的2.明确超乙酰化在线粒体功能障碍中的作用。这个 高乙酰化对氧化磷酸化、氧化应激和糖尿病心肌病的影响将被确定。这将通过a)乙酰化蛋白质的MS分析；b)确定超乙酰化引起的功能变化；以及c)确定糖尿病引起的超乙酰化的原因。目的3.确定PKA在代谢不灵活和线粒体功能障碍中的作用。这一目标将检验我们观察到的PKA活性下降是 通过氧化和/或乙酰化来调节。机制研究将确定这些修饰的发生和对线粒体呼吸活性和自由基产生的影响。

Cardiovascular disease is the leading cause of death among people with diabetes and may occur in the absence of other known risk factors. Mitochondrial bioenergetic deficits and increased free radical production are pathological hallmarks of diabetic cardiomyopathy (DCM). A goal of this project is to determine the molecular changes that occur in mitochondria to induce metabolic dysfunction and oxidative stress. Specifically, we are addressing how dysregulated mitochondrial protein lysine acetylation contributes to metabolic inflexibility, mitochondrial dysfunction, and the progression of DCM. Our hypothesis is that hyperglycemia leads to increased, pathological protein lysine acetylation of specific metabolic enzymes, such as protein kinase A, and this contributes to fatty acid oxidation, mitochondrial dysfunction, and increased oxidative stress. Using a transgenic rodent model of type 1 diabetes and cell culture techniques, we will test the hypothesis as follows: Aim 1. Define the changes that occur to mitochondria that lead to mitochondrial dysfunction and increased oxidative stress with the progression of diabetes. Mitochondrial substrate selection, oxidative phosphorylation, and free radical production will be analyzed in parallel with changes in cardiac structure and function using magnetic resonance imaging (MRI) and histology. Aim 2. Define the contribution of hyper-acetylation to mitochondrial dysfunction. The consequences of hyper-acetylation on oxidative phosphorylation, oxidative stress, and diabetic cardiomyopathy will be determined. This will be done by a) MS analysis of acetylated proteins; b) identifying the functional changes that hyperacetylation induces; and c) identifying the cause of diabetes induced hyperacetylation. Aim 3. Determine the role of PKA in contributing to metabolic inflexibility and mitochondrial dysfunction. This aim will test the hypothesis that our observed decrease in PKA activity is mediated by oxidation and/or acetylation. Mechanistic studies will determine the occurrence and consequences of these modifications on mitochondrial respiratory activity and free radical production.