年龄相关性白内障发生过程中miRNA-145影响E2F3功能的分子机制

Cataract is one of the severest problems of an aging population in China. Operation as the predominant treatment modality is far from meeting the demand of sharp increase in the amount of cataract patients. The development of non-operation treatment is restricted by etiological uncertainty. For the past few years, Epigenetics provide new insights into the etiology of cataract. MircoRNAs(miRNAs) is one kind of small RNAs with 21-25nt length, it can pair with mRNA to suppress translation, and result in pathological changes by repressing genes expression. In our previous experiments, it has been observed that miR-145 had obviously different expression between transparent and cataractous human lens. By using prediction algorithms, E2F3 which is involved in development of lens was been predicted to be regulated by miR-145. However, molecular mechanisms of E2F3' function affected by miR-145 are not clear, further research needed to identify the relationships between miR-145 and formation of cataract. Based on the above reasons, we will explore the mechanisms of miR-145 on E2F3 by molecular biotechnology, and also validate whether miR-145 would cause cataract by regulating E2F3 in lens epithelium cells.

白内障是我国人口老龄化最严峻的问题之一。以手术为主的治疗模式已经远远不能满足数量剧增的白内障患者的复明需求，而发病机制不明确却严重限制着非手术治疗的发展。近年来，表观遗传学的发展为我们提供了新的思路。MircoRNAs（miRNAs）是长度为21-25nt 的小分子 RNA，通过碱基互补原则与目标 mRNA 结合并抑制其翻译，进而下调相应基因的表达引起相应病理生理改变；在前期实验中我们已经检测到miRNA-145在正常和年龄相关性白内障的晶状体中表达差异显著，并预测到其可调节晶状体发育相关基因E2F3的表达。然而，miRNA-145影响E2F3功能的分子机制尚未明确，与年龄相关性白内障发生病理改变的关系也需进一步的实验。因此，我们拟通过分子生物学技术探索miRNA-145对E2F3功能影响的具体机制，同时验证miR-145是否可以通过调节晶状体细胞的E2F3的表达，而导致白内障的发生。

白内障是影响老年人生活质量的重要疾病。尽管手术效果不错，但远不能满足数量剧增的白内障患者的复明需求。近年来，表观遗传学的发展为我们提供了新的思路。MircoRNAs（miRNAs）是长度约为22nt 的小分子 RNA，通过碱基互补原则与目标 mRNA 结合并抑制其翻译，进而下调相应基因的表达引起相应病理生理改变；在前期实验中检测到miR-145在正常和年龄相关性白内障的晶状体中表达差异显著，并预测到其可调节晶状体发育相关基因E2F3的表达。然而，miR-145影响E2F3功能的分子机制尚未明确，与年龄相关性白内障发生的病理改变的关系也需进一步的实验。因此，我们拟通过分子生物学技术探索miR-145对E2F3功能影响的具体机制，同时验证miR-145是否可以通过调节晶状体细胞的E2F3的表达，而导致白内障的发生。在实验过程中，发现miR-145不能抑制E2F3的表达，由此我们更换了microRNA，选择另外一个在年龄相关性白内障的晶状体中高表达的miR-34a，并通过软件预测其可能与E2F3的3’UTR相结合。结果显示miR-34a可以特异性地与E2F3的3’UTR结合，表明E2F3 是 miR-34a 的靶基因；同时，miR-34a通过下调 E2F3 的表达，抑制晶状体上皮细胞增殖，同时诱导晶状体上皮细胞发生凋亡。提示 miR-34a 可能参与白内障的发生，为白内障的药物研制提供了实验依据。