LncRNA MEG3在糖尿病肾病足细胞损伤中的作用及机制研究

Diabetic nephropathy is a common and refractory microvascular complications of diabetes. It is known that podocyte damage is an important reason for the development of diabetic nephropathy. However, the mechanism of podocyte damage is unclear. In our preliminary studies, we applicated the lncRNAs microarray technology to detect and screen the specific lncRNAs of diabetic nephropathy, and validated using quantitative real-time polymerase chain reaction. We found that lncRNA MEG3 was significantly upregulated in kidney tissue of both diabetic nephropathy patients and mouse. Over-expression of MEG3 can significantly promote podocyte apoptosis. We used RNA pull-down experiments to screen and found that the MEG3 bound with the anti-apoptotic protein BIRC5. So we proposed the possible mechanisms that MEG3 mediated podocytes damage is that MEG3 combines with BIRC5 and inhibits its anti-apoptotic function when diabetic nephropathy, then leading to podocyte damage. We intend to further confirm that lncRNA MEG3 directly combines with the protein BIRC5, and explore the importance and significance of the incident on BIRC5 function silence and podocyte damage. The study may find a new mechanism of podocyte damage in early diabetic nephropathy, and provide new ideas and methods for the prevention and treatment of diabetic nephropathy.

糖尿病肾病（DN）是糖尿病常见且难治的微血管并发症，肾小球足细胞损伤是导致DN发生发展的重要原因。但是，足细胞损伤的机制尚不清楚。我们在前期研究中，应用lncRNAs芯片技术检测并筛选了DN特异表达的lncRNAs，经验证发现lncRNA MEG3在临床DN患者和DN小鼠肾组织中均显著高表达；上调表达MEG3能明显促进足细胞凋亡；RNA pull-down实验筛选发现MEG3与抗凋亡蛋白质BIRC5相结合。我们提出MEG3介导足细胞损伤的可能机制，即DN时MEG3 与BIRC5结合并抑制其抗凋亡的功能，从而导致足细胞损伤。本项目拟进一步证实MEG3与蛋白BIRC5直接结合，并探讨这一事件对BIRC5的功能沉默和足细胞损伤的重要性和意义。本研究可能发现一种新的早期DN足细胞损伤的机制，为临床防治糖尿病肾病提供新的思路和方法。

糖尿病肾病（Diabetic nephropathy, DN）是糖尿病常见且难治的微血管并发症，高糖环境、肾小球病变后滤出的细胞因子及蛋白质等刺激肾小管上皮细胞分泌炎症因子，促使单核／巨噬细胞浸润肾间质，进而促进肾小管间质纤维化。由此可见，炎症和纤维化两者在DN发展中密不可分。目前，越来越多证据表明lncRNA的异常表达与DN的发生、发展密切相关，然而其参与DN的发生机制尚不明确。. 本研究应用lncRNA高通量芯片技术筛选db/db DN小鼠肾组织中差异表达的lncRNAs，并明确其在DN小鼠肾组织中的表达，进一步从动物、细胞和分子水平探讨其作用及机制，为阐明糖尿病肾病发病的分子机制提供实验依据。. 本研究发现：. 1.高通量lncRNAs芯片检测结果显示与db/m对照小鼠肾组织相比，db/db DN小鼠肾组织有686个差异表达的lncRNAs，其中lncRNA MEG3是上调表达最显著的lncRNA。 LncRNA MEG3在db/db DN小鼠肾组织及高糖刺激小鼠系膜细胞和小鼠肾小管上皮细胞的表达均增高。LncRNA MEG3位于小鼠肾小管上皮细胞和系膜细胞的胞浆。. 2.LncRNA MEG3促进小鼠肾小管上皮细胞和小鼠系膜细胞炎症因子分泌和纤维化蛋白合成。. 3.体内转染lncRNA MEG3长效siRNA 可明显下调db/db DN小鼠肾脏lncRNA MEG3表达，体内下调lncRNA MEG3可降低db/db DN小鼠尿白蛋白／肌酐值，可减轻db/db DN小鼠肾间质巨噬细胞浸润，可减轻db/db DN小鼠肾脏炎症因子表达及减缓肾脏纤维化。. 4.生物信息学预测miR-212-5p是与lncRNA MEG3直接结合的microRNAs之一，lncRNA MEG3可作为ceRNA竞争性结合miR-212-5p。