The Role of RAGE in Diabetes and Myocardial Infarction.

描述（由申请人提供）：心肌梗死是发病率和死亡率的主要因素，糖尿病可加重心肌梗死。然而，糖尿病患者对心脏损伤易感性增加的机制尚不清楚。我们实验室先前的研究已经揭示了晚期糖基化终产物受体（receptor for advanced glycation end-products，RNTs）在心肌梗死中的核心作用，因为RNTs的整体缺失导致缺血/再灌注（I/R）后48小时与野生型同窝仔相比，心肌坏死减少，功能恢复增加和ATP保存增加。在影响心肌对I/R损伤的反应的多种细胞类型中表达，例如单核细胞/巨噬细胞、内皮细胞和心肌细胞。我们已经发现，心肌缺血导致I/R后的氧化应激，并影响伴随心脏损伤的线粒体功能障碍。在糖尿病条件下和I/R后，配体增加，导致下游信号传导增加。我们的实验室已经发现，Rho胞质结构域与Rho GTPases家族的成员和Rho GTPases的效应子透明质酸-1（mDia-1）相互作用。这项研究的总体目标是研究心肌细胞对I/R损伤的反应中的mDia 1/mDia 1信号传导。我们预测，心肌细胞特异性β 2和mDia，在I/R后小鼠心脏中均高度上调，在心肌中发出破坏性代谢后果的信号，从而引发线粒体功能障碍。理想情况下，这项研究将转化为改善糖尿病患者发生心肌梗死的预后。为了实现这一目标，我们将使用I/R的左前降支冠状动脉结扎模型，用于在mDia 1和mDia 1表达中具有遗传变异的糖尿病和非糖尿病小鼠品系。我们将通过超声心动图评估由于遗传应变引起的I/R诱导的左心室功能障碍的差异。此外，我们将在从野生型和转基因小鼠中分离的心肌细胞中进行更有针对性的缺氧/复氧研究。我们将使用离体灌注心脏模型来评估线粒体功能。我所提出的研究将提供信息，指导未来的努力，治疗糖尿病患者谁经历了心肌梗死，并防止进一步并发症的发展。此外，这个项目将帮助我完成我的培训目标，即1）表征和使用转基因小鼠来测试假设，即mDia 1/mDia 1信号传导导致心肌中破坏性的代谢后果，2）使用原代心肌细胞来解决所涉及的机制，3）采用离体灌注的缺血/再灌注心脏模型来解决假设，4）掌握使用生理学相关模型评估I/R损伤。这项研究的成功完成将增加我的知识，技能和潜力，以实现我成为心血管疾病独立研究人员的最终目标。

DESCRIPTION (provided by applicant): Myocardial infarction is a major contributor to morbidity and mortality and is exacerbated by diabetes. However, the mechanisms underlying this increased susceptibility to cardiac injury in diabetic patients are not well understood. Previous studies by our laboratory have revealed a central role for the receptor for advanced glycation end-products (RAGE) in myocardial infarction, as global deletion of RAGE resulted in decreased myocardial necrosis, increased functional recovery and preservation of ATP compared to wild-type littermates 48 hours after ischemia/reperfusion (I/R). RAGE is expressed in multiple cell types that impact the myocardial response to I/R injury, such as monocytes/macrophages, endothelial cells, and cardiomyocytes. We have uncovered that RAGE contributes to oxidative stress consequent to I/R and influences mitochondrial dysfunction that accompanies injury to the heart. Ligands for RAGE are increased under diabetic conditions and after I/R, leading to increased downstream signaling. Our laboratory has discovered that the RAGE cytoplasmic domain interacts with diaphanous-1 (mDia-1), a member of the formin family, and an effector of Rho GTPases. The overall goal of the proposed research is to investigate RAGE/mDia1 signaling in cardiomyocytes in response to I/R injury. We predict that cardiomyocyte-specific RAGE and mDia, both highly upregulated in the murine heart after I/R, signal devastating metabolic consequences in the myocardium, which trigger mitochondrial dysfunction. Ideally, this research will translate into an improved prognosis for diabetic patients who have undergone myocardial infarction. To meet this goal, we will use the left anterior descending coronary artery ligation model of I/R in strains of diabetic and non- diabetic mice with genetic variations in RAGE and mDia1 expression. We will assess differences in I/R-induced left ventricular dysfunction due to genetic strain by echocardiography. Additionally, we will perform more targeted studies of hypoxia/reoxygenation in cardiomyocytes isolated from wild type and transgenic mice. We will use the ex vivo perfused heart model to assess mitochondrial function. My proposed studies will provide information to guide future efforts for the treatment of diabetic patients who have undergone myocardial infarction and prevent the development of further complications. In addition, this project will help me accomplish my training goals, which are to 1) characterize and use transgenic mice to test the hypothesis that RAGE/mDia1 signaling lead to devastating metabolic consequences in the myocardium, 2) use primary cardiomyocytes to address the mechanisms involved, 3) employ the ex vivo perfused heart model of ischemia/reperfusion to address the hypothesis, and 4) master the use of physiologically relevant models to assess I/R injury. The successful completion of this research will increase my knowledge, skill set, and potential to achieve my ultimate goal of becoming an independent researcher in cardiovascular disease.