血管生成素样蛋白3通过整合素参与糖尿病视网膜病变的机制

The pathological course of diabetic retinopathy (DR) includes nonproliferative DR (NPDR) and proliferative DR (PDR). It has been reported that angiogenin-like protein 4 (ANGPTL4) promotes aberrant angiogenesis in PDR, and it is not clear which factors play an important role in the progression and outcome of DR. ANGPTL3 and ANGPTL4 belong to a family that binds to integrin αVβ3 and regulates endothelial cell proliferation and migration. We found that plasma ANGPTL3 level in patients with type 2 diabetes was positively correlated with the severity of DR, but not with ANGPTL4. The levels of retinal vascular proliferation and ANGPTL3 expression in db/db mice at 24 weeks were higher than those in 8-week db/db mice. Bioinformatics prediction showed ANGPTL3 also binds to integrin α5, which is closely related to inflammation,in addition to αVβ3. Based on this, we hypothesized that ANGPTL3 could promote the development of DR through the impairment of retinal vascular endothelial cells by integrin. This reseach intends to clear this key molecular mechanisms of ANGPTL3 that promote endothelial cell damage and abnormal vascular proliferation by integrin αv and α5 through db/db diabetic mice and ANGPTL3 knockout mice ,providing the basis of prevention and treatment of DR.

糖尿病视网膜血管病变（DR）的病理过程包括非增殖性DR（NPDR）和增殖性DR（PDR）。研究报道房水中血管生成素样蛋白4（ANGPTL4）促进异常血管生成参与PDR。ANGPTL3和ANGPTL4属于一个家族，都与整合素αVβ3结合，调节内皮细胞增殖和迁移。我们发现，2型糖尿病患者血浆ANGPTL3水平与DR各期严重程度呈正相关；24周龄db小鼠眼球血管增生和ANGPTL3表达水平均高于8周db小鼠；生物信息学预测发现，除了αVβ3，ANGPTL3还可结合整合素α5，而α5与炎症密切相关。据此，我们假设：ANGPTL3通过整合素损伤视网膜血管内皮细胞，促进DR发生发展。本课题拟通过db/db糖尿病小鼠、ANGPTL3基因敲除小鼠明确ANGPTL3通过整合素αV和α5促进内皮细胞损伤和异常血管增生的关键分子机制，为DR防治提供依据。

糖尿病视网膜病变（DR）是糖尿病患者最常见的并发症之一，是全球低视力和失明最主要的原因，针对DR的治疗手段极其有限。2型糖尿病患者血浆血管生成素样蛋白3（ANGPTL3）水平与DR各期严重程度呈正相关，基于此，我们提出科学假设：ANGPTL3通过整合素损伤视网膜血管内皮细胞，促进DR发生发展。本项目在DR小鼠模型、ANGPTL3基因敲除小鼠模型中探讨了ANGPTL3与DR的关系，同时在体外血管内皮细胞中探讨ANGPTL3影响血管内皮细胞增殖、凋亡、成管及细胞连接等方面的影响。研究结果显示，在DR小鼠模型中，ANGPTL3表达明显升高，同时ANGPTL3与血管内皮细胞标志物CD31存在共表达，而予以ANGPTL3病毒干预后视网膜眼底血管渗漏明显加重。在体外细胞实验中，予以重组ANGPTL3干预后血管内皮细胞增殖、迁移增多，成管增多，而予以整合素α5或整合素αV后，ANGPTL3的上述效应被明显削弱。综上所述，本项目研究结果提示ANGPTL3通过整合素α和整合素αV促进DR的进展。ANGPTL3可能成为DR的治疗靶点，为DR的治疗提供了理论依据。