sFlt-1基因靶向敲除诱导鼠新生血管性眼底病及其机制的实验研究

21.正常光信号的产生需要无血管的光感受器与其周围血管丰富的脉络膜分开不被血管侵入。这种矛盾的生理结构的分子机制尚不清楚。无血管的光感受器层被其周血管侵入引起视网膜瘤样增生和脉络膜新生血管化，是年龄相关性黄斑变性（AMD）的两种病理基础。AMD是我国及西方国家最主要的不可逆性盲,其发病机制尚不清楚。本课题将通过观察sFlt-1（可溶性血管内皮生长因子受体1）的表达，首次证实光感受器和视网膜色素上皮细胞（RPE）可以合成sFlt-1， sFlt-1随年龄增加表达下降，尤其是AMD眼明显下降。通过转录、翻译及基因水平，靶向敲除光感受器和视网膜色素细胞 的sFlt-1，诱发新生血管性视网膜病变；以及用Cre/lox技术分别靶向定点敲除光感受器或RPE的Flt-1基因，建立两种不同类型的AMD转基因鼠模型。探讨sFlt-1在维持光感受器无血管特性的作用和AMD的发病机制，为基因治疗提供理论依据。

Optimal phototransduction requires precise separation of a highly vascularized choroid adjacent to yet not invading the avascular photoreceptor layer. How these contradictory imperatives are reconciled molecularly is unclear. Breakdown of peri-photoreceptor vascular demarcation leads to retinal angiomatous proliferation (RAP) or choroidal neovascularization (CNV), two variants of vascular invasion of the photoreceptor layer in age-related macular degeneration, the leading cause of blindness in the world. This study will confirm that sFLT-1, an endogenous inhibitor of vascular endothelial growth factor-A, is synthesized by the retinal photoreceptors and retinal pigment epithelium, and is decreased in age-related macular degeneration. Suppression of sFLT-1 by antibodies, adeno-associated virus -mediated RNA interference, or Cre/lox mediated gene ablation either in the photoreceptor layer or below induces free VEGF-A and abolishes photoreceptor avascularity， and advance two transgenic murine models of age-related macular degeneration.The mechanism of the neovascular retinal desease and sFlt-1 will be studied. All these findings can provide a proof theoretically for gene therapy.