lncRNALL18介导Wnt与TTF-1在高氧早产鼠BPD上皮细胞损伤修复中共活化机制的研究

The core content to figure out BPD of premature is to complete alveolization by normalized alveolar epithelial cells repairment after damaging. Previous studies have found that the changes of Wnt signaling pathways lead to abnormal proliferation and transdifferentiation of AEC-Ⅱin the BPD induced by hyperoxia. And it is found that the expression of Wnt5a and lncRNALL18 has the same spatial and temporal expression pattern in the endotoxin induced lung injury. Their specific relationship is unclear. The transcriptional coactive of Wnt（classic and/or non classical） and TTF-1 being mediated by lncRNALL18 would be studied through animal models, molecular cell mechanism and genetic therapy, which regulates AEC proliferation and differentiation. We predict binding sites of lncRNALL18 and TTF-1 DNA or mRNA and testify the role of lncRNALL18 activating TTF-1. We will confirm gene of lncRNALL18 transferred with SB transposon or electroporation technology would prevent or cure BPD of premature rats. Then it may explicit that Wnt --lncLL18--TTF-1 regulates process of alveolization in BPD, provide new targets and ideas for preventing and treating BPD to achieve a better prognosis.

肺泡上皮细胞损伤修复使肺泡化完成是解决早产儿BPD的核心内容。前期研究发现Wnt信号通路在高氧BPD中表达改变导致AEC-Ⅱ增殖转分化异常；并发现，内毒素肺损伤时Wnt5a与lncRNALL18具有一致的时空表达模式。它们的具体关系尚不清楚。本研究拟从模型动物、分子细胞以及基因治疗等水平研究Wnt信号（经典和/或非经典）通路通过lncRNALL18实现与TTF-1转录因子的共活化，调控AEC的增殖转化；预测lncRNALL18与TTF-1DNA或者mRNA的结合位点并验证lncRNALL18靶向激活TTF-1的作用；证实模型动物使用SB转座子、电穿孔技术转lncRNALL18基因方法可以预防或者治疗早产鼠BPD。明确Wnt --lncLL18--TTF-1调控BPD时肺泡化程度，为逐年增多的早产儿BPD的预防和治疗提供新的靶点和思路。

为研究BPD早产鼠lncRNA对Ⅱ型肺泡上皮细胞（AEC-Ⅱ）增殖及其向Ⅰ型肺泡上皮细胞（AEC-Ⅰ）转分化的调控机制。采用已建立的高氧诱导早产鼠BPD模型及体外培养AEC-Ⅱ及其转分化的AEC-Ⅰ，研究：①lncRNA LL18及其他相关lncRNA在早产鼠正常肺发育及BPD发生中的肺组织以及AEC-Ⅱ中表达规律；②Wnt通路与lncRNA之间对BPD早产鼠AEC-Ⅱ增殖转分化的调控机制。重要结果: 高氧诱导早产鼠BPD病理过程中，Wnt5a、lncRNA LL18和TTF-1时空表达模式与AEC-Ⅱ损伤、增殖异常相关，Wnt--lncRNA LL18--TTF-1中任何一个节点的改变均可导致肺泡化障碍；具体表现为：①Wnt（Wnt5a/PCP）信号通路的活性改变直接影响lncRNA LL18的表达，继而在转录水平调控TTF-1 mRNA的表达，TTF-1表达的改变反馈性影响Wnt信号通路的功能。②非经Wnt通路动态变化改变lncRNA LL18--TTF-1的功能，引起BPD过程中AEC-Ⅱ增殖转分化能力的动态改变。③外源性lncRNALL18治疗高氧组早产鼠，可减轻高氧诱导BPD中的肺泡化障碍。④此外，在BPD中LncRNA GAS5能够作为miR-1912-3p的分子海绵与其结合，促进其下游靶基因Sox9的表达，能够早期抑制Wnt经典信号通路的过度激活，促进AEC-II的增殖和分化。科学意义：肺泡上皮细胞损伤是疾病的起始，也是病变的重中之重，lncRNA LL18参与重要信号转导通路Wnt和关键转录因子TTF-1的共活化，进一步深入的研究 BPD的分子生物学机制。同时，更具体的探索经典/非经典Wnt信号通路在BPD发生发展的不同阶段调控AEC-Ⅱ增殖转分化的细节内容，为今后的精准医学提供新思路。