以肝X受体为靶点的基因治疗对糖尿病视网膜病变视网膜神经血管单元的保护作用研究

糖尿病视网膜病变(DR)为神经血管性疾病,是成年人首位致盲原因。我们前期研究发现:1)VEGF-VEGFR2介导的视网膜神经血管单元(RNVU)损伤是DR的重要病理基础;2)胆固醇逆向转运关键调控因子肝X受体基因(LXR)在高糖环境下由于VEGF高表达而失活,抑制下游靶基因ABCA1及ABCG1表达,阻滞细胞内胆固醇逆向转运过程;而LXR激动剂Rg1可逆转这一病理过程。我们的科学假说:LXR信号通路可保护高血糖所致的RNVU损伤。本项目拟通过:1)体外实验将载有LXR基因的rAAV载体转导原代视网膜血管内皮细胞以及神经节细胞验证目的基因正确表达并发挥功能2)动物在体实验:通过玻璃体给药在正常和大鼠DR早期渗漏模型中验证rAAV-CMV-LXR-GFP-FC的高效转导性、高度靶向性、LXR基因的长期表达水平以及在RNVU损伤保护中的重要作用,为LXR基因治疗DR打下基础。

Diabetic retinopathy (DR) is a neuro-vascular complication of diabetes and is the leading cause of blindness in adults. Our previous study found that dys-function of retinal neovascular unit (RNVU) which is medicated by VEGF-VEGFR2 signal transduction pathway is an important pathophysiological factor of DR. We further discovered that the liver X receptor gene (LXR, a key regulator of cholesterol metabolism dynamic balance), is inactivated under the high glucose environment (diabetes). Decreased expression of LXR gene further inhibits the expression of its downstream genes ABCA1 and ABCG1, leading to the inhibition of intracellular cholesterol reverse transport; and the LXR agonist Rg1 reverses this pathological process. We propose a scientific hypothesis that LXR and its pathway could inhibit dysfunction of the RNVU and prevent or prohibit the progress of DR. This project aims to: 1) investigate the effect of the rAAV vector carrying the LXR gene on human retinal endothelial cells:2) and to further investigate if rAAV-CMV-LXR-GFP-FC is highly transfusable, targeted, and long-term expression of LXR gene in STZ induced diabetic rats, further to test the hypothesis that rAAV mediated gene therapy play an important role in the maintenance the normal function of RNVU in DR. The project will provide the new insight towards the gene therapy for DR.