METTL3-mediated mature miR-497-5p/195-5p inhibits trophoblast migration and invasion by targeting WWP1 in preeclampsia.

Preeclampsia (PE) is a pregnancy-associated disorder caused by poor placentation. METTL3 as an RNA methyltransferase that plays an essential role in the regulation of the m6A modification. This work investigated the regulation of METTL3-mediated mature miR-497-5p/195-5p cluster in PE progression and identified the downstream mechanisms involved. Differentially expressed miRNAs in PE were obtained from the GSE96983 dataset. The miR-497-5p/195-5p levels in placental samples collected from 20 cases of PE patients and 18 cases of normal controls were measured by RT-qPCR. Effects of miR-497-5p/195-5p and WWP1 on trophoblast proliferation, migration, and invasion were analyzed by CCK8, EdU, wound healing and Transwell assays. Luciferase reporter and RIP experiments were conducted to verify the interaction of WWP1 with miR-497-5p/195-5p. Dot blot assay was performed to determine the m6A levels in PE. The m6A modification of pri-miR-497-5p/195-5p was determined by Me-RIP assay. Immunochemistry (IHC) and western blotting were used to examine the immunoreactivities and protein levels of METTL3 and WWP1 in placental samples from PE patients and normal controls. The miR-497-5p/195-5p levels were high in PE placenta. Functionally, overexpression of miR-497-5p/195-5p prevented trophoblast migration, invasion, and proliferation. WWP1 overexpression enhanced trophoblast migration, invasion, and proliferation. Mechanistically, WWP1 was verified to be targeted by miR-497-5p/195-5p. Moreover, METTL3 promoted the recognition of pri-miR-497-5p/195-5p by DGCR8 and enhanced the formation of mature miR-497-5p/195-5p in an m6A manner. We demonstrated that METTL3-mediated m6A modification promotes the transition of pri-miR-497-5p/195-5p to mature miRNAs, thereby upregulating miR-497-5p/195-5p to aggravate PE progression by targeting WWP1.