HMGB1介导的滋养细胞自噬异常在子痫前期发病机制中的作用

Abnormal autophagy of trophoblast is associated with preeclampsia, but the molecular mechanism is still unclear. HMGB1, a trigger of oxidative stress-mediated autophagy in tumor cells, is upregulated in maternal serum and placenta of preeclampsia. Our preliminary experiments found that recombinant human HMGB1 promoted trophoblast autophagy and exosome formation in first trimester placentae. Based on the above, we propose a hypothesis of the pathogenesis of preeclampsia: the up-regulation of trophblast HMGB1 expression induced by the oxidative stress in local placentae, promotes trophoblast autophagy, leading to aberrant trophoblast invasion, and promotion of exosome formation resulting in abnormal activation of endothelial cells. In order to validate the hypothesis we design the following proposal. First, the impacts of recombinant human HMGB1 on trophoblast autophagy will be detected in first trimester placentae in vitro. Second, HTR8/SVneo trophoblast cells will be cultured in normoxia and anoxia condition, and the changes of HMGB1 expression and cell autophagy will be investigated. Finally, transfection technique will be used to up-regulate or down-regulate the expression of HMGB1/RAGE/Beclin1 in trophoblast, then the abnormal autopahgy of trophoblast via HMGB1-RAGE or HMGB1-Beclin1 pathways, the changes of trophoblast biology behavior and exosome formation will be examined. This project will provide new targets from the aspect of HMGB1- mediated trophoblast autophagy for the prevention of preeclampsia.

滋养细胞自噬异常与子痫前期相关，但分子机制尚不明确。HMGB1是氧化应激下肿瘤细胞自噬触发器，且子痫前期胎盘和母血HMGB1表达上调。预试验发现人重组HMGB1诱导早孕绒毛滋养细胞自噬和外泌体形成。据此，我们提出假说：胎盘局部氧化应激诱导滋养细胞HMGB1表达上调，促进滋养细胞自噬，抑制其侵袭能力；同时促进外泌体形成，异常活化血管内皮细胞，从而导致子痫前期的发生。本项目将体外培养早孕绒毛，研究人重组HMGB1对早孕绒毛滋养细胞自噬的影响；其次，缺氧培养滋养细胞株，检测细胞HMGB1表达及自噬改变；最后，采用转染技术上调/下调滋养细胞HMGB1/RAGE/Beclin1表达，研究HMGB1-RAGE或HMGB1-Beclin1通路参与的自噬异常对滋养细胞生物学行为和外泌体形成的影响。本项目将从HMGB1介导的滋养细胞自噬方面为子痫前期的防治提供新的靶点。

胎盘滋养细胞侵袭不良和血管内皮细胞损伤是子痫前期的主要病理特征。研究发现子痫前期胎盘滋养细胞胞质和母血HMGB1表达上调。.人重组HMGB1与早孕绒毛共培养，发现早孕绒毛滋养细胞自噬和外泌体释放增加。滋养细胞外泌体中，发现了339个差异表达的蛋白，132个蛋白表达上调，207个蛋白表达下调。其中CAV2、YAP1表达分别上调100%和80%。人微血管内皮细胞HMEC-1摄取了高表达CAV2、YAP1的外泌体后，发生了细胞活化，促进炎症因子的释放。.滋养细胞株HTR8可能通过HMGB1-RAGE-MAPK-Erk1/2-mTOR-p70S6K通路促进细胞自噬，细胞侵袭能力下降。HTR8可能通过ph-MLKL促进外泌体的释放。.滋养细胞自噬的调节可能是子痫前期防治的新靶点。.