Unraveling ApoE4 Promotion of Cardiometabolic Disease

项目摘要/摘要 与表达最常见的载脂蛋白E(ApoE)基因变体的个体相比， 载脂蛋白E4基因携带者患心血管疾病和2型糖尿病的风险增加 糖尿病(T2 DM)。尽管载脂蛋白E经典地参与了脂质运输，但载脂蛋白E4相关风险的基础 仍然不清楚，也没有可用的干预措施来打破载脂蛋白E4和血管和 代谢紊乱。我们最近发现，在表达人类基因的小鼠身上观察到的胰岛素抵抗 载脂蛋白E4由内皮细胞载脂蛋白E受体ApoER2介导的骨骼肌胰岛素抵抗所驱动 细胞。培养研究表明，其潜在的机制是apoE4-ApoER2诱导的抑制 血管内皮细胞的胰岛素转运，这对胰岛素在肌肉中的作用有重大影响。在最近的其他工作中 我们确定，在表达apoE4的小鼠中，血栓形成明显比表达apoE3的小鼠严重。细胞 培养研究进一步表明，这可能是由于载脂蛋白E4促进了von Willebrand因子(Vwf)。 内皮细胞的分泌。拟议研究的总体目标是阐明载脂蛋白E4是如何起作用的 血管内皮细胞影响血糖稳态和血管疾病的发病机制。目标1将决定如何 载脂蛋白E4会导致胰岛素抵抗。对ApoER2相互作用蛋白的无偏倚质疑及其后续研究 培养内皮细胞的胰岛素转运提示DAB2相互作用蛋白(DAB2IP)和 JIP1，两者都调制JNK信号。利用内皮细胞特异性缺失apoE3-和apoE4- 在小鼠中表达，我们将检验apoE4通过内皮ApoER2促进胰岛素抵抗的假设 通过DAB2IP和JIP1依赖的机制。目标2将确定apoE4如何促进 动脉粥样硬化和血栓形成。内皮细胞和载脂蛋白E4与载脂蛋白ER2相互作用的研究 血管内皮细胞vWF分泌和单核细胞黏附增强提示可能参与了 蛋白磷酸酶PP2A。在apoE3和apoE4表达的小鼠中，我们将检验apoE4的假设 通过内皮ApoER2相关的PP2A活化促进动脉粥样硬化和血栓形成。在目标1和目标2中， 我们还将使用基于GWAS的策略来确定小鼠的操作基因是否为修饰性基因 影响人类代谢和血管疾病载脂蛋白E4相关风险的基因。在目标3中，我们将设计 干预载脂蛋白E4及其维持代谢和血管健康的作用机制。在……里面 JNK抑制对小鼠胰岛素抵抗的影响及PP2A抑制对ApoE4小鼠胰岛素抵抗的影响 将对动脉粥样硬化和血栓形成进行评估。我们还将使用碱基编辑来对apoE4进行基因校正 对载脂蛋白E4小鼠肝细胞体内载脂蛋白E3的影响。编辑效率及其对载脂蛋白E4相关胰岛素的影响 将评估抵抗力、动脉粥样硬化和血栓形成。通过实现这些目标和解开 载脂蛋白E4如何促进心脏代谢性疾病，预计新的治疗方法将被开发出来 在15%到20%的人口中中和代谢和血管疾病的重要基因贡献。

Project Summary/Abstract Compared with individuals expressing the most common genetic variant of apolipoprotein E (apoE), apoE3, those harboring apoE4 are at increased risk of both cardiovascular disease and type 2 diabetes mellitus (T2DM). Although apoE classically participates in lipid transport, the basis for apoE4-associated risk remains unclear, and there are no interventions available to break the link between apoE4 and vascular and metabolic disorders. We recently discovered that the insulin resistance observed in mice expressing human apoE4 is driven by skeletal muscle insulin resistance mediated by the apoE receptor apoER2 in endothelial cells. Studies in culture showed that the underlying mechanism is apoE4-apoER2-induced inhibition of endothelial cell insulin transport, which has a major impact on insulin action in muscle. In other recent work we determined that thrombosis is markedly more severe in apoE4- versus apoE3-expressing mice. Cell culture studies further indicated that this may be due to apoE4 promotion of von Willebrand factor (vWF) secretion by endothelial cells. The Overall Goal of the proposed research is to elucidate how apoE4 actions on endothelium influence glucose homeostasis and vascular disease pathogenesis. Aim 1 will determine how apoE4 causes insulin resistance. A non-biased query of apoER2-interacting proteins and ensuing studies of insulin transport in cultured endothelial cells suggest involvement of Dab2-interacting protein (DAB2IP) and JIP1, which both modulate JNK signaling. Using endothelial cell-specific deletion in apoE3- and apoE4- expressing mice, we will test the hypothesis that apoE4 promotes insulin resistance via endothelial apoER2 through DAB2IP- and JIP1-dependent mechanisms. Aim 2 will determine how apoE4 promotes atherosclerosis and thrombosis. Studies of proteins interacting with apoER2 in endothelium and apoE4 enhancement of endothelial cell vWF secretion and monocyte adhesion indicate possible participation of the protein phosphatase PP2A. In apoE3- and apoE4-expressing mice we will test the hypothesis that apoE4 promotes atherosclerosis and thrombosis via endothelial apoER2-related activation of PP2A. In Aims 1 and 2, we will additionally use GWAS-based strategies to determine if the operative genes in mice are modifier genes influencing apoE4-related risk of metabolic and vascular disease in humans. In Aim 3 we will devise interventions against apoE4 and its mechanisms of action to preserve metabolic and vascular health. In apoE4 mice the effect of JNK inhibition on insulin resistance and the effect of PP2A inhibition on atherosclerosis and thrombosis will be evaluated. We will also use base editing to genetically correct apoE4 to apoE3 in vivo in the hepatocytes of apoE4 mice. Editing efficiency and impact on apoE4-related insulin resistance, atherosclerosis and thrombosis will be evaluated. By accomplishing these Aims and unraveling how apoE4 promotes cardiometabolic disease, it is expected that novel therapies can then be developed to neutralize an important genetic contribution to metabolic and vascular disease in 15 to 20% of the population.