lncRNA-MEG9调控肝双向潜能干细胞活化通路在胆道闭锁引发的肝损伤修复中的作用

Biliary atresia (BA) is one of the most life-threatening diseases that damage the liver in newborns. Liver transplantation is currently the first-line treatment for BA. Due to shortage of the liver donors, the overall prognosis of BA is far from satisfactory. Previous studies have revealed the increase of liver bi-potent stem cells (LBSC) in response to BA in animal models. However, the mechanism underlying LBSC re-activation and the following biological consequences in the disease development are not clear. Here, we have compared the lncRNA expression profile between BA-induced fibrotic liver and normal liver tissues and found MEG9 was selectively upregulated in the liver upon BA stimulus. We aim to validated the MEG9 expression in human and mouse pathological tissues of BA. We also intend to isolated mouse LBSC in vitro, in which MEG9 is then over-expressed or silenced to investigate its function in LBSC self-renew and directed differentiation. We further use RIP strategy to identify proteins interacting with MEG9 to elucidate the downstream molecular mechanism. We further testify the therapeutic effect of ex vivo MEG9-activated LBSC in animal models of BA. Collectively, our study firstly shows the critical role of lncRNA in BA and suggests LBSC as promising novel therapeutic strategy for BA treatment.

胆道闭锁是小儿肝移植中最常见的适应症，发病机制尚不清楚，且治疗手段较局限，整体预后有待于提高。前期研究提示肝双向潜能干细胞在胆道闭锁动物模型中有活化，然而其分子机制及作用尚不清楚，治疗效果也不详。该项目通过前期对比性分析胆道闭锁肝纤维化组织和正常肝组织间的lncRNA差异，发现MEG9在胆道闭锁肝组织中选择性上调。我们拟进一步在人和动物模型的肝组织中验证该lncRNA的表达。同时，在体外分离肝双向潜能干细胞，通过正向/负向调控MEG9来研究其对肝干细胞自我更新和定向分化的影响。并通过RNA-pull-down来研究与MEG9相互作用的蛋白质，确定其下游信号通路。并在体外将MEG9活化的肝双向潜能干细胞回输至胆道闭锁模型中，观察其对胆道闭锁造成的肝损伤的修复效果。该研究首次在胆道闭锁模型中研究了lncRNA的生物学功能，由MEG9介导活化的干细胞为治疗胆道闭锁造成的肝损伤提供了新的策略。

胆道闭锁是小儿肝移植中最常见的适应症，发病机制尚不清楚，且治疗手段较局限，整体预后有待于提高。我们前期研究通过对比性分析胆道闭锁肝纤维化组织和正常肝组织间的lncRNA差异，发现lnRNA MEG9在胆道闭锁肝组织中选择性上调。我们进一步在BA患儿的肝组织中验证该lncRNA的高表达，同时明确了其对诊断胆道闭锁的价值。后续实验表明，lncRNA MEG9改变胆管上皮细胞的生物学行为，可能以此参与胆道闭锁的发病过程。另外，通过RNA pulldown研究与MEG9相互作用的蛋白质，并结合RNA-seq富集分析结果，确定其下游信号通路。本课题应用转录组学、分子生物学及生物信息学等技术和方法，首次在胆道闭锁中，从细胞、类器官、动物及临床四个水平，探讨lncRNA MEG9的功能及其分子网络调控系统，为胆道闭锁病理机制研究提供了新的策略。