MicroRNA-29通过ZONAB调节BPD新生鼠肺泡上皮细胞增殖及转分化的研究

As an alveolar developmental disorder, bronchopulmonary dysplasia (BPD) is recently considered to be associated with alveolar epithelial cells (AEC) repair disorder after oxidative stress and inflammatory factors injury, however, the mechanism remains unknown. We have previously found injuries of structure in both type II alveolar epithelial cells (AEC II) and AEC I, on the basis of that, we speculate that injury of AEC II is not the only way affecting lung repair and that the disorder of proliferation and transdifferentiation from AEC II to AEC I may also work, which results in poor repair after injury. As an entry point, we will build overexpression and deletion cell model of transcription factor ZONAB to verify the key regulatory function of ZONAB on proliferation and transdifferentiation of AECs. On the basis of our previous research about the microRNA chip screening in BPD models, we will further explore the targeted interacting relationship between microRNA-29 (miR-29) and ZONAB by using luciferase reporter gene method. The present study will use miR-29 mimic and inhibitor to confirm that miR-29- ZONAB- proliferation and transdifferentiation of AECs pathway may play an important role in regulating alveolar epithelial cell repair after injury, which would provide new idea for prediction and treatment of BPD.

早产儿支气管肺发育不良(BPD)是一种肺泡发育障碍性疾病，近年来对氧化应激、炎症介质损伤后肺泡上皮细胞(AEC)修复障碍的研究逐渐成为热点，但发病机制尚未完善。本项目在前期研究发现BPD模型中II型肺泡上皮细胞（AEC II）及AEC I结构均损伤的基础上，提出AEC II损伤并非肺上皮修复障碍的唯一机制，还可能存在细胞增殖及AEC II向AEC I转分化异常，导致损伤后修复不良。并以转录因子ZONAB为切入点，构建ZONAB过表达及缺失细胞模型，阐明ZONAB是调节AEC增殖及转分化的关键因子；在前期microRNA芯片筛选的基础上，应用荧光素酶报告基因技术确定micro RNA-29（miR-29）与ZONAB的靶向作用关系，通过转染miR-29模拟物及抑制物，最终阐明miR-29-ZONAB-AEC增殖及转分化途径可能在肺上皮损伤修复中发挥重要作用，为早期预测及治疗BPD提供新思路。

1、在体内及体外支气管肺发育不良模型中，II型肺泡上皮细胞不但无增殖障 碍，而且向I型肺泡上皮细胞转分化增多。.2、支气管肺发育不良模型中，虽然II型肺泡上皮细胞增殖及转分化均增多， 但仍然不能弥补肺上皮屏障功能的破坏。.3、ZONAB作为调节细胞增殖及分化的重要转录因子，在正常发育的肺泡上 皮中有表达，但暴露于高氧后II型肺泡上皮细胞表达ZONAB减少，这种ZONAB 表达异常可能导致II型肺泡上皮细胞向I型肺泡上皮细胞转分化增多。.4、体外原代培养的II型肺泡上皮细胞通过基因转染的方法证实，ZONAB具 有促进肺泡上皮细胞增殖，抑制其转分化的作用。因此，适当调控肺泡上皮细胞 中ZONAB的表达量可能是调节肺上皮损伤后修复的一条新途径，也成为研究支.气管肺发育不良防治方法的一个新靶点。