Dyslipidemia, Lipoic Acid and Diabetic Vascular Complications in Humanized

描述(由申请人提供)： 虽然糖尿病会导致许多器官的严重损害，但心血管疾病是糖尿病患者死亡和发病的主要原因。总体而言，与非糖尿病患者相比，糖尿病患者患冠状动脉疾病的风险增加了三到五倍。我们的目标是利用小鼠遗传学来识别糖尿病血管并发症的遗传危险因素，并解开潜在的机制。虽然在致动脉粥样硬化的小鼠模型中，糖尿病导致的动脉粥样硬化显著增加，但这些小鼠模型都不能忠实地复制与人类糖尿病相关的血脂异常类型。我们推测，这种失败是由于血浆低密度脂蛋白(LDL)和高密度脂蛋白(HDL)的相对水平不同，这是由两个物种之间的遗传差异和人类的遗传多态控制的。因此，我们的第一个假设是，将参与小鼠脂蛋白代谢的基因人源化，使它们产生更像人类的糖尿病血脂异常，将使它们更好地复制人类糖尿病患者的心血管问题。我们将在特定目标1中通过人源化载脂蛋白E三种异构体(E2、E3和E4)和人源化低密度脂蛋白受体(LDLR)在有或没有人载脂蛋白B过表达的情况下诱导小鼠糖尿病来检验这一假设。我们预测，这将导致糖尿病血脂异常，并以载脂蛋白E异构体依赖的方式加速动脉粥样硬化。我们的第二个假设是，由于糖尿病被普遍认为会导致氧化应激，基因决定的内源性抗氧化剂水平的差异会影响心血管并发症的发展。为了验证这一假设，我们在特定目标2中建议开发一种新的小鼠模型，该模型具有遗传控制的内源性抗氧化剂硫辛酸(LA)的产生减少。我们将以这样一种方式修改LA合成酶(LiAS)基因，使Lias mRNA的稳定性以组织特异性的方式急剧降低。我们的假设预测，LA产量的减少将增加糖尿病小鼠已经存在的氧化应激，并促进它们发生血管并发症。在具体目标3中，我们建议将类人型糖尿病血脂异常与由于LA缺乏而导致的遗传抗氧化能力降低结合起来，以检验我们的整体论文，即影响血脂谱的遗传多态差异和影响内源性抗氧化剂水平的遗传差异之间的相互作用决定了糖尿病增强心血管疾病的程度。

DESCRIPTION (provided by applicant): While diabetes mellitus can lead to serious damage to many organs, cardiovascular diseases are the major cause of death and morbidity in diabetic patients. Overall, patients with diabetes have a three to five fold increased risk of coronary artery diseases compared to non-diabetics. Our goal is to use mouse genetics for identifying genetic risk factors for the vascular complications of diabetes and for unraveling underlying mechanisms. Although a significant increase in atherosclerosis by diabetes has been demonstrated in atherogenic mouse models, none of these mouse models faithfully replicates the types of dyslipidemia associated with diabetes in humans. We postulate that this failure is due to differences in the relative levels of plasma low density lipoprotein (LDL) and plasma high density lipoprotein (HDL) that are controlled by genetic differences between the two species and genetic polymorphisms in humans. Thus our first hypothesis is that humanizing genes that are involved in lipoprotein metabolism in mice so that they develop a more human-like diabetic dyslipidemia will cause them to replicate better the cardiovascular problems of human diabetic patients. We will test this hypothesis in Specific Aim 1 by inducing diabetes in mice with humanized apoE of the three isoforms (E2, E3, and E4) and humanized LDL receptor (LDLR), with or without overexpression of human apoB. We predict that this will lead to diabetic dyslipidemia and accelerated atherosclerosis in an apoE isoform dependent manner. Our second hypothesis is that since diabetes is generally acknowledged to induce oxidative stress, genetically determined differences in the levels of endogenous anti-oxidants affect the development of cardiovascular complications,. To test this hypothesis, we propose in Specific Aim 2 to develop a new mouse model with a genetically controlled reduction in the production of the endogenous antioxidant lipoic acid (LA). We will modify the LA synthase (Lias) gene in such a way that the stability of Lias mRNA will be drastically reduced in a tissue specific fashion. Our hypothesis predicts that reduced production of LA will increase the oxidative stress already present in diabetic mice and enhance their development of vascular complications. In Specific Aim 3, we propose to combine human-like diabetic dyslipidemia with genetically reduced antioxidant capacity due to LA deficiency to test our overall thesis that interactions between genetic polymorphic differences affecting lipid profiles and genetic differences affecting endogenous antioxidant levels determine the degree to which diabetes enhances cardiovascular disease.