Role of Diabetes-Induced REDD1 in Heart Disease

项目摘要 心力衰竭是糖尿病和肥胖症患者死亡和发病的主要原因，但仍有许多问题有待解决。 关于代谢疾病引起心肌功能障碍的分子事件尚不清楚。在 细胞水平、氧化应激和炎症被认为是心肌损伤的标志。的 这个F31奖学金提案的首要假设是，应激反应蛋白调节， 发育和DNA损伤1（REDD 1）在心脏病的发病机制中起着适应不良的作用， 增加心肌细胞中氧化应激和炎症的发展。初步数据支持 REDD 1表达在喂食Western的小鼠心脏中增强（即，高脂肪、高蔗糖）饮食， 心肌细胞培养物暴露于饱和脂肪酸棕榈酸酯。我们实验室的最新研究 证明了REDD 1在糖尿病诱导的氧化应激发展中的关键作用。更具体地说， REDD 1通过GSK-3β依赖性信号轴抑制核因子红细胞-2相关因子2 （Nrf 2）在糖尿病小鼠视网膜中的抗氧化反应。此外，REDD 1被发现可以促进 通过直接隔离κB抑制剂（IκB），导致核因子 κ B（NF-κB）活化。REDD 1在激活Nrf 2的这两个非常规信号轴中的作用 抑制和NF-κB激活的机制尚未在心脏中得到研究。也不知道REDD 1是否有助于 心脏功能障碍的发展。为了验证这个假设，我将进行一项实验， 从完整小鼠到心肌细胞培养物的模型系统。目的1将研究其机制 由此，西方饮食的消耗促进心脏中REDD 1的转录上调。目标2将 研究REDD 1在心肌细胞氧化应激和炎症发展中的作用。目的 3将确定REDD 1缺失对心功能不全发展的影响。除了我 继续在宾夕法尼亚州立大学医学院进行分子生物学和细胞生理学的研究生培训， 研究金将提供与心血管功能障碍专家一起进行重要培训的机会。具体来说，我会 学习正确培养和操作成年心室心肌细胞并发展技术专业知识 超声心动图来评估REDD 1对转基因小鼠心脏功能的影响。相对于 结果，该项目不仅将扩大我的技能和分析系统超越我的主要 申办者，但也可能确定和表征一个统一的监管机制，代谢 疾病限制了内源性抗氧化反应并上调了心脏炎症。查明这类 建立一个机制是重要的，因为它将为制定预防和/或 旨在解决心力衰竭的分子基础的治疗干预。

Project Summary Heart failure is a leading cause of mortality and morbidity in patients with diabetes and obesity, yet much remains unknown regarding the molecular events whereby metabolic disease causes myocardial dysfunction. At the cellular level, oxidative stress and inflammation are considered hallmarks of myocardial impairment. The overarching hypothesis for this F31 fellowship proposal is that the stress response protein regulated in development and DNA damage 1 (REDD1) plays a maladaptive role in the pathogenesis of heart disease by augmenting the development of oxidative stress and inflammation in cardiomyocytes. Preliminary data support that REDD1 expression is enhanced in the heart of mice fed a Western (i.e., high fat, high sucrose) diet and in cardiomyocyte cultures exposed to the saturated fatty acid palmitate. Recent studies from our laboratory demonstrate a key role for REDD1 in the development of diabetes-induced oxidative stress. More specifically, REDD1 acts via a GSK-3β-dependent signaling axis to suppress the nuclear factor erythroid-2-related factor 2 (Nrf2) antioxidant response in the retina of diabetic mice. Additionally, REDD1 was found to promote inflammatory signaling in macrophages by direct sequestration of inhibitor of κB (IκB), leading to nuclear factor kappa B (NF-κB) activation. A role for REDD1 in activation of these two non-conventional signaling axes for Nrf2 repression and NF-κB activation has never been interrogated in the heart. Nor is it know if REDD1 contributes to the development of cardiac dysfunction. To test the hypothesis, I will pursue an experimental protocol involving model systems ranging from intact mice to cardiomyocyte cell cultures. Aim 1 will investigate the mechanism whereby consumption of a Western diet promotes transcriptional upregulation of REDD1 in the heart. Aim 2 will investigate the role of REDD1 in the development of oxidative stress and inflammation in cardiomyocytes. Aim 3 will determine the impact of REDD1 deletion on the development of cardiac dysfunction. In addition to my continued graduate training in molecular biology and cellular physiology at Penn State College of Medicine, this fellowship will provide key training opportunities with experts in cardiovascular dysfunction. Specifically, I will learn to properly culture and manipulate adult ventricular cardiomyocytes and develop the technical expertise in echocardiography to assess the impact of REDD1 on cardiac function in transgenic mice. With respect to outcomes, the project will not only expand my skills and systems of analysis beyond those of my primary Sponsor, but will also potentially identify and characterize a unifying regulatory mechanism whereby metabolic disease limits the endogenous antioxidant response and upregulates inflammation in heart. Identification of such a mechanism is significant because it will validate new targets for the development of preventative and/or therapeutic interventions aimed at addressing the molecular basis of heart failure.