ARDS时Wnt/β-catenin-p130/E2F4调控细胞周期影响MSC向肺泡上皮分化的机制研究

Diffuse alveolar epithelial cells injury is the major pathology of ARDS. Effective repair of damage alveolar epithelial has a key role to the treatment and the improvement the prognosis of ARDS. Our previous experiments have confirmed the activation of canonical Wnt pathway promoted exogenous mesenchymal stem cells (MSC) to homing into lung tissue and differentiation into lung epithelial cells in acute respiratory distress syndrome (ARDS) mice. Many studies found that the cell cycle involved in differentiation of MSC, and the canonical Wnt pathway can regulate the p130/E2F4 patheway which is the key regulators of the cell cycle. We hypothesize that canonical Wnt pathway promotes the differentiation of MSC into lung epithelial cells through regulation of p130/E2F4 pathway. In this study, MSC is co-cultured with lung epithelial cells injured by lipopolysaccharide, and the p130/E2F4 pathway is regulated through gene modification mediated by lentivirus transfection, then to assay the effect of the p130/E2F4 pathway on the differentiation of MSC into lung epithelial cells.In addition ,we assay the effect of p130/E2F4 pathway on the homing and differentiation of MSC into lung epithelial cells , and the lung injury repair after LPS challenged in mice.It may illustrate that the effect of activation of canonical Wnt pathway on promotion of differentiation of MSC into lung epithelial cells is achieved by regulating the cell cycle through regulation of the p130/E2F4 pathway. This study may provide an evidence for lung epithelium repair in ARDS and facilitate the further improvement of MSC-based treatment for ARDS.

弥漫性肺泡上皮损伤是ARDS的基本病理改变，有效修复损伤肺泡上皮对治疗ARDS具有关键作用。我们前期实验已证实Wnt经典通路能促进外源性MSC向ARDS小鼠损伤肺组织归巢并分化为肺上皮细胞。细胞周期在MSC定向分化中发挥关键作用，p130/E2F4是调控细胞周期的重要途径，而Wnt经典通路能调节p130/E2F4，推测Wnt经典通路通过p130/E2F4途径调控MSC的细胞周期促进其向肺泡上皮细胞定向分化。本研究基于MSC和肺上皮细胞共培养模型，通过基因转染调控p130/E2F4途径，明确Wnt经典通路通过p130/E2F4调节细胞周期而促进MSC向肺泡上皮细胞定向分化；通过复制小鼠ARDS模型，给予p130/E2F4基因转染的MSC，观察其对MSC在肺内归巢、分化及肺上皮修复的影响，证实Wnt经典通路促进MSC分化通过p130/E2F4实现，为提高MSC对ARDS肺上皮修复提供新的依据。

弥漫性肺泡上皮损伤是ARDS的基本病理改变，有效修复损伤肺泡上皮对治疗ARDS具有关键作用。前期实验已证实经典Wnt通路能促进外源性MSC在ARDS小鼠肺内分化为肺上皮细胞，其具体机制不清。细胞周期在MSC分化中发挥关键作用，p130/E2F4是调控细胞周期的重要途径，而经典Wnt通路能调节p130/E2F4。推测经典Wnt通路通过调节p130/E2F4影响MSC的细胞周期进而调控其向肺泡上皮细胞定向分化。.本研究基于MSC和肺上皮细胞共培养模型，通过基因转染调控p130/E2F4途径，探讨Wnt/β-Catenin-p130/E2F4调控细胞周期进而影响MSC体外向肺泡上皮细胞分化的机制；并复制小鼠ARDS模型，给予高表达p130/E2F4的MSC，观察其对MSC在肺内归巢、分化及肺上皮修复的影响，揭示高表达p130/E2F4促进MSC分化，为提高MSC对ARDS肺上皮修复提供新的依据。.研究结果：（1）高表达p130或E2F4能促进mMSCs向AT II分化，其机制可能与G1期延长相关；（2）调控经典Wnt信号通路可影响mMSCs向AT II分化并影响mMSCs中p130/E2F4蛋白表达，其机制可能与G1+S期的变化相关；（3）高表达p130或E2F4能促进mMSCs减轻ARDS小鼠肺组织病理损伤、增加mMSCs在ARDS小鼠肺组织的存留、促进mMSCs在ARDS小鼠肺内向AT II分化、改善ARDS小鼠肺通透性并减轻ARDS小鼠肺纤维化。.该研究证实经典Wnt信号通路可通过调控p130/E2F4影响mMSCs向II型肺泡上皮细胞分化，其机制可能与延长mMSCs的G1期相关；高表达p130或E2F4能增加mMSCs在ARDS小鼠肺组织存留，并通过促进mMSCs向AT II分化，从而改善肺上皮通透性、减轻肺水肿程度并增强mMSCs改善肺纤维化的作用，更进一步促进mMSCs修复ARDS肺损伤。