Eaf2基因调控microRNA抑制白内障发生的机制研究

Cataract is a kind of aged disease of eye and an important cause of severe visual impairment in old people. Complex pathogenesis and molecular interactions dictate injury steps leading to the cataract. Eaf2 has recently been implicated as a potential gene critical for cataract pathogenesis. Eaf2 expressed in the lens fiber cell and retina during the eye development process. However, the role of Eaf2 within the complex mechanisms of cataract genesis remains elusive. Our previous study firstly observed the cataract genesis in conventional Eaf2 knockout mice. Eaf2 knockout mice were found to demonstrate phenotype of cataract at early age of after UV induction. Loss of Eaf2 down-regulates miRNA-184 expression in the lens. And miRNA-184 mutation is one of most important regulator in cataract genesis and caused anterior polar cataract. Our present study focus on the mechanism of cataract genesis according to the results we found. We investigated the relationship between Eaf2, p53 and downstream microRNA, such as miRNA-184 et al, using Eaf2 convertional knockout mice and p53 transgenic mice by Microarry, ISH, real time RT-PCR, ChIp, Immunofluorescein et al. We provide the evidence that the Eaf2 gene is critically involved in lens cell proliferation, apoptosis and differentiation, leading to cataract genesis at RNA regulation facet. The results will provide the first direct genetic evidence for the mechanism of Eaf2 knockout lead to cataract and the distinct function of Eaf2 in regulating lens cell cycle.

有关白内障易感基因的致病机制、表达调控机制的研究是国际上眼科学研究领域的前沿和热点。申请人前期工作中利用ELL相关因子2（Eaf2）基因敲除小鼠在国际上首次发现Eaf2基因在成熟晶状体内大量表达，Eaf2基因敲除后可以下调miRNA-184的转录进而导致白内障。本课题围绕Eaf2基因表达缺失导致白内障这一学术理论，在前期工作基础上，以研究Eaf2调控microRNA及其下游靶基因的分子机制为核心，通过基因重组、免疫荧光、Microarray、免疫沉淀和生物信息学分子等研究手段，结合先进的Eaf2基因敲除小鼠和p53转基因小鼠等，在体及离体对Eaf2基因表达缺失后通过p53基因调控晶状体内microRNA的表达进行从表征到分子机理的研究。在RNA水平揭示Eaf2表达缺失导致白内障的分子机制，也为白内障易感基因的转录调控研究提出了新的方向，为深入研究白内障的发生机制提供新的思路和实验依据。

白内障已成为世界人口老龄化所面临的最严峻问题之一，探索一种经济有效的非手术防治新途径，具有重要的学术价值和社会效益。本项目以Eaf2基因对晶状体内miRNA的转录调控机制为研究核心，通过分子生物学、生物信息学等研究手段，结合Eaf2基因敲除小鼠，在体及离体对Eaf2、miRNA及其下游靶基因调控白内障发生的分子机制进行研究，发现Eaf2基因能够调控多个miRNA的表达，及其下游与凋亡密切相关的多个靶基因如Bcl-2家族、Caspase家族、ERK信号通路以及Noxa、Puma基因的表达，影响晶状体上皮细胞凋亡，从而在白内障发病过程中发挥重要作用，在RNA水平上进一步揭示了白内障的发病机制，Eaf2基因及其调控的miRNA可能成为白内障诊断和治疗中一种新的生物学标记或药物新靶点，为非手术靶向治疗白内障提供重要的实验基础和依据。