秦宇等

[摘要] 目的 探讨microRNA let-7a靶向调控Caspase家族的机制及其在年龄相关性白内障发病过程中的作用。方法 收集2014年7～9月在中国医科大学附属第四医院（以下简称“我院”）眼科诊断为年龄相关性白内障（排除其他眼部疾病）的患者晶状体前囊膜标本30例，作为实验组；同时收集我院眼科眼库提供的新鲜人眼透明晶状体前囊膜标本15例，作为对照组。利用生物信息学软件预测let-7a可能调控的Caspase家族中的关键基因；采用实时荧光定量PCR（Real time q-PCR）检测实验组和对照组let-7a及其预测靶基因的表达；利用Lipofectamine 2000瞬时转染let-7a mimic和inhibitor，调节人晶状体上皮细胞中let-7a的表达，利用Real time q-PCR法验证转染效率，并检测预测靶基因的表达变化。 结果 3种不同的生物信息学软件预测到Caspase家族中Caspase-3、Caspase-8、Caspase-9可能为let-7a的靶基因。与对照组比较，实验组let-7a的表达显著降低，Caspase-3、Caspase-8、Caspase-9的表达显著升高。let-7a mimic转染组，let-7a的表达显著升高，Caspase-3、Caspase-8、Caspase-9的表达显著降低；let-7a inhibitor转染组，let-7a的表达显著降低，Caspase-3、Caspase-8、Caspase-9的表达显著升高；差异均有高度统计学意义（P < 0.01）。 结论 let-7a可能通过靶向调控Caspase家族成员Caspase-3、Caspase-8、Caspase-9的表达，在年龄相关性白内障发病过程中发挥重要作用，let-7a可能成为白内障非手术治疗的新靶点。

[关键词] 微小RNA；let-7a；Caspase家族；白内障

[中图分类号] R776.1 [文献标识码] A [文章编号] 1673-7210（2015）06（b）-0004-06

Research of microRNA let-7a targeted Caspase family in the pathogenesis of cataract

QIN Yu1 ZHANG Jinsong1 MIN Xiaojie1 LUO Wenting2 LI Jing1 ZHAO Jiangyue1

1.Department of Ophthalmology， the Fourth Affiliated Hospital of China Medical University Eye Hospital of China Medical University Key Lens Research Laboratory of Liaoning Province， China， Liaoning Province， Shenyang 110005， China； 2.Key Laboratory of Health Ministry for Congenital Malformation， Shengjing Hospital， China Medical University， Liaoning Province， Shenyang 110004， China

[Abstract] Objective To study the mechanism of microRNA let-7a targeted Caspase family in the pathogenesis of age-related cataract. Methods 30 fresh specimens of anterior lens capsule of age-related cataract were obtained as experimental group from cataract patients with no other eye diseases during phacoemulsification at the Department of Ophthalmology， the Fourth Affiliated Hospital of China Medical University（“our hospital” for short） form July to September 2014. 15 normal anterior lens capsule specimens were obtained as control group from eye bank of Department of Ophthalmology in our hospital. Biological information softwares were used to predict potential target genes of let-7a in Caspase family. Real time q-PCR was used to measure the expression of let-7a and potential target genes between the experimental group and the control group. Let-7a mimic and inhibitor were transfected into SRA01/04 cells using Lipofectamine 2000 to regulate the expression of let-7a， and then real time q-PCR was used to assess transfection efficiency and the expression of potential target genes. Results Caspase-3， Caspase-8 and Caspase-9 were predicted as the potential target genes of let-7a using three different biological information softwares. Compared with control group， the expression of let-7a was significantly lower in the experimental group. On the contrary， the expression of Caspase-3， Caspase-8 and Caspase-9 increased in the same tissue specimens. The relative expression of let-7a in lens epithelial cells transfected with let-7a mimic increased， whereas decreased in cells transfected with let-7a inhibitor. The expression of Caspase-3， Caspase-8 and Caspase-9 transfected with let-7a mimic were reduced， while increased in let-7a inhibitor group， the differences were statistically significant （P < 0.01）. Conclusion Let-7a may play a critical role in the pathogenesis of age-related cataract by targeting caspase-3， Caspase-8 and Caspase-9 in Caspase family. Let-7a might be a new target for nonoperative treatment of cataract.

[Key words] microRNA； let-7a； Caspase family； Cataract

线粒体通路是最主要的凋亡通路，而晶状体上皮细胞凋亡是除先天性白内障外其他类型白内障形成的共同细胞学基础，因而线粒体通路在白内障的发病过程中发挥着重要作用。线粒体通路包括发挥凋亡调节作用的蛋白和发挥凋亡执行作用的蛋白，前者主要是B淋巴细胞瘤/白血病-2（Bcl-2）家族成员，后者主要是天冬氨酸特异性的半胱氨酸酶（Caspase）家族成员。Caspase家族包括凋亡启动蛋白酶如Caspase-8、Caspase-9等，和凋亡效应蛋白酶如Caspase-3等，其中Caspase-3是细胞凋亡的关键蛋白酶[1]。……