Unraveling ApoE4 Promotion of Cardiometabolic Disease

项目总结/摘要 与表达载脂蛋白E（apoE）最常见遗传变异的个体相比， 携带apoE 4的人患心血管疾病和2型糖尿病的风险增加 糖尿病（T2 DM）。虽然apoE通常参与脂质转运，但apoE 4相关风险的基础 目前尚不清楚，也没有干预措施可以打破apoE 4与血管和 代谢紊乱我们最近发现，在表达人胰岛素的小鼠中观察到的胰岛素抵抗， apoE 4由骨骼肌胰岛素抵抗驱动，骨骼肌胰岛素抵抗由内皮细胞中apoE受体apoER 2介导。 细胞在培养物中的研究表明，潜在的机制是apoE 4-apoER 2诱导的抑制， 内皮细胞胰岛素转运，其对肌肉中的胰岛素作用具有主要影响。在最近的其他工作中， 我们确定了在apoE 4表达小鼠中血栓形成比apoE 3表达小鼠明显更严重。细胞 培养研究进一步表明，这可能是由于apoE 4促进血管性血友病因子（vWF） 由内皮细胞分泌。这项研究的总体目标是阐明apoE 4的作用机制。 影响血糖稳态和血管疾病的发病机制。目标1将决定如何 apoE 4导致胰岛素抵抗。apoER 2相互作用蛋白质的无偏倚查询和随后的研究 培养内皮细胞中胰岛素转运提示Dab 2相互作用蛋白（DAB 2 IP）参与， JIP 1，两者都调节JNK信号传导。使用内皮细胞特异性缺失apoE 3-和apoE 4- 我们将检验apoE 4通过内皮细胞apoER 2促进胰岛素抵抗的假设 通过依赖DAB 2 IP和JIP 1的机制。目的2将确定apoE 4如何促进 动脉粥样硬化和血栓形成。内皮细胞apoER 2和apoE 4相互作用蛋白的研究 内皮细胞vWF分泌和单核细胞粘附的增强表明， 蛋白磷酸酶PP 2A。在表达apoE 3和apoE 4的小鼠中，我们将检验apoE 4 通过内皮apoER 2相关的PP 2A活化促进动脉粥样硬化和血栓形成。在目标1和2中， 我们还将使用基于GWAS的策略来确定小鼠中的操作基因是否是修饰基因， 影响人类代谢和血管疾病apoE 4相关风险的基因。在目标3中，我们将设计 针对apoE 4的干预及其保护代谢和血管健康的作用机制。在 apoE 4小鼠JNK抑制对胰岛素抵抗的影响和PP 2A抑制对胰岛素抵抗的影响。 将评价动脉粥样硬化和血栓形成。我们还将使用碱基编辑来遗传校正apoE 4 apoE 4小鼠肝细胞中apoE 3的表达。编辑效率和对apoE 4相关胰岛素的影响 将评估阻力、动脉粥样硬化和血栓形成。通过实现这些目标， 关于apoE 4如何促进心脏代谢疾病的研究，预计可以开发新的治疗方法， 在15%到20%的人口中，消除了对代谢和血管疾病的重要遗传贡献。

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.