糖化apoA-IV促进动脉粥样硬化发生及机制研究

Vascular protective effect of HDL is significantly attenuated in diabetes, and this is partially related to the glycation modification of apolipoproteins. We have identified that apoA-IV can be glycated in diabetic milieu. Our study shows that glycation degree is associated with the severity of coronary atherosclerosis in diabetic patients. It is known that apoA-IV possess anti-inflammatory, anti-oxidative and anti-atherosclerotic property. Our experiments have shown that glycated recombinant apoA-IV exerts pro-inflammatory effects and induces monocytoid macrophage-endothelial cell adhesion; and promotes migration and lipid intake in macrophages, which phenomenon are significantly mitigated by normal apoA-IV. The examination of glycated apoA-IV-treated endothelial cells and human monocytes by mRNA chip shows that nuclear receptor NR4A3 is remarkably elevated. Moreover, the pro-inflammatory effect of glycated apoA-IV requires NR4A3 mediation. Collectively, these results indicate that glycated apoA-IV may promote atherogenesis via mediation of NR4A3 in diabetes. In the following experiments, we will test this hypothesis and clarify the mechanism in cellular and in vivo study of wide-type and NR4A3-KO mice. Furthermore, the partners of glycated apoA-IV will be searched using a proteomic approach to identify molecular action site.

糖尿病时血管保护因素-HDL功能异常，这与HDL中载脂蛋白糖化修饰有关。我们发现，糖尿病时apoA-IV被糖化。apoA-IV糖化程度与冠脉粥样硬化严重性相关。结合文献和前期研究，apoA-IV存在于HDL和游离血液中，具有抗炎、抗氧化和抑制动脉粥样硬化的功能。糖化apoA-IV促进炎症反应和巨噬细胞-内皮细胞黏附；增强氧化应激；促进单核巨噬细胞迁移吞脂。而正常apoA-IV则抑制这些病理。 mRNA芯片显示并被证实，糖化apoA-IV处理显著上调内皮和巨噬细胞中核受体NR4A3表达，而apoA-IV抑制其表达。糖化apoA-IV诱导炎症反应需NR4A3介导。提示糖尿病时糖化apoA-IV可能经NR4A3介导促进动脉粥样硬化发生。后续将以体内和体外实验，探讨糖化apoA-IV对野生型和NR4A3-KO小鼠动脉粥样硬化的影响和对细胞的作用；阐明机制和致病途径，揭示其作用位点和潜在干预靶点。

糖尿病时血管保护因素-HDL功能异常，这与HDL中载脂蛋白糖化修饰有关。我们发现，糖尿病时apoA-IV被糖化。apoA-IV糖化程度与冠脉粥样硬化严重性相关。结合文献和前期研究，apoA-IV存在于HDL和游离血液中，具有抗炎、抗氧化和抑制动脉粥样硬化的功能。糖化apoA-IV促进炎症反应和巨噬细胞-内皮细胞黏附；增强氧化应激；促进单核巨噬细胞迁移吞脂。而正常apoA-IV则抑制这些病理。 mRNA芯片显示并被证实，糖化apoA-IV处理显著上调内皮和巨噬细胞中核受体NR4A3表达，而apoA-IV抑制其表达。糖化apoA-IV诱导炎症反应需NR4A3介导。提示糖尿病时糖化apoA-IV可能经NR4A3介导促进动脉粥样硬化发生。对健康人，糖尿病非合并CAD病人，糖尿病合并CAD的病人apoA-IV行LC-MS/MS分析后，我们在糖尿病合并CAD的病人HDL中发现了19个apoA-IV的CML糖化位点，为了进一步寻找与疾病关系最为密切的apoA-IV糖化CML位点，我们构建了糖化的位点突变的apoA-IV,并利用此蛋白刺激HAECs细胞，并建立腹腔注射此突变蛋白的apoE敲除小鼠模型，实验结果显示，与为突变的糖化apoA-IV相比，突变的糖化apoA-IV能显著降低黏附因子表达，并减少动脉粥样硬化斑块的形成。