MicroRNA-138 improves LPS-induced trophoblast dysfunction through targeting RELA and NF-κB signaling

Preeclampsia is a pregnancy complication classified by new onset of elevated blood pressure and proteinuria after 20 weeks of gestation. During preeclampsia, extra villous trophoblasts fail to adequately invade the myometrial spiral arteries, leading to incomplete and impaired vessel transformation and initiating or aggravating preeclampsia. Although NF-κB and proinflammatory cytokines have been reported to be related to trophoblast dysfunction, the underlying mechanism remains unclear. Herein, we demonstrated the miR-138/RELA axis modulating the migratory ability, and invasive ability of HTR-8/SVneo and JEG-3 cells, as well as the inflammatory factor levels in response to LPS stimulation. miR-138 expression was upregulated in preeclampsia placenta and LPS-stimulated HTR-8/SVneo and JEG-3 cell lines. miR-138 overexpression rescued the migratory and invasive ability of HTR-8/SVneo and JEG-3 cells inhibited by LPS stimulation, and decreased LPS-induced TNF-α and IL-6 levels. By binding the 3’-UTR of RELA, miR-138 negatively regulated p65 expression. The silencing of p65 also improved LPS-induced HTR-8/SVneo and JEG-3 cell dysfunction and TNF-α and IL-6 levels. More importantly, p65 overexpression partially reversed the functions of miR-138 overexpression upon both cells, indicating that miR-138 exerted its biological effects through targeting RELA. In conclusion, miR-138 improves LPS-induced inflammation and oxidative stress on trophoblasts through targeting RELA and affecting NF-κB signaling. The miR-138/RELA axis might be involved in preeclampsia pathogenesis, which requires further <i>in vivo</i> and clinical researches.

子痫前期（Preeclampsia）是一种妊娠并发症，以妊娠20周后新发高血压与蛋白尿为诊断分类依据。子痫前期发病过程中，绒毛外滋养细胞无法充分浸润子宫肌层螺旋动脉，导致血管重塑不完全且功能受损，进而诱发或加重子痫前期。尽管已有研究证实核因子κB（NF-κB）与促炎细胞因子与滋养细胞功能障碍相关，但其潜在分子机制仍未阐明。本研究证实，miR-138/RELA轴可调控HTR-8/SVneo与JEG-3细胞的迁移、侵袭能力，以及脂多糖（LPS）刺激下的炎症因子表达水平。miR-138在子痫前期胎盘及脂多糖刺激后的HTR-8/SVneo、JEG-3细胞系中表达上调。过表达miR-138可挽救脂多糖刺激诱导的HTR-8/SVneo与JEG-3细胞迁移、侵袭能力受损，并降低脂多糖诱导的肿瘤坏死因子α（TNF-α）与白细胞介素6（IL-6）水平。miR-138通过结合RELA的3’非翻译区（3’-UTR）负调控p65的表达。沉默p65同样可改善脂多糖诱导的HTR-8/SVneo与JEG-3细胞功能障碍，并降低TNF-α与IL-6的分泌水平。更为关键的是，过表达p65可部分逆转miR-138过表达对两种细胞产生的生物学效应，提示miR-138通过靶向RELA发挥其生物学功能。综上，miR-138通过靶向RELA并影响NF-κB信号通路，改善脂多糖诱导的滋养细胞炎症反应与氧化应激。miR-138/RELA轴可能参与子痫前期的发病进程，该结论有待进一步的体内（in vivo）与临床研究予以验证。