METTL3 suppressing SLC31A1 m6A modification regulates trophoblast migration and invasion

Objective: This article aims to explore the mechanism of METTL3-mediated SLC31A1 N6-methyladenosine (m6A) modification affecting trophoblast migration and invasion in preeclampsia (PE). Methods: The PE model was established using N-nitro-arginine methyl ester induction. Blood pressure was measured on gestation day (GD) 0, 5, 10, 15, and 20, and urine protein concentration on the day before mating and GD 20. HTR-8 SV/neo cells were cultured in vitro and treated with si-METTL3, oe-METTL3, oe-SLC31A1, siSLC31A1, or RSM3 (METTL3 inhibitor). METTL3 and SLC31A1 were detected by immunohistochemistry and Western blot. After corresponding treatment, HTR-8SV/neo cells were measured for viability, cell damage, proliferation, migration and invasion and apoptotic rate. m6A modification level was measured by methylated RNA immunoprecipitation while the interactions between METTL3 and SLC31A1 mRNA, and YTHDF2 and SLC31A1 mRNA was determined by RNA immunoprecipitation. Results: PE rats showed elevated METTL3 and down-regulated SLC31A1 expression. Treatment with si-METTL3 or oe-SLC31A1 suggested increased cell viability, proliferation, migration and invasion, and reduced cell damage and apoptosis rate, while cells treated with oe-METTL3 or si-SLC31A1 had reversed results. Up-regulating SLC31A1 partially reversed the inhibitory effect of METTL3 on HTR-8SV/neo cell migration and invasion. METTL3 reduced SLC31A1 mRNA stability and inhibited SLC31A1 expression through m6A modification in a YTHDF2-dependent manner. Furthermore, the in vivo experiments confirmed that METTL3 promotes PE progression through m6A methylation of SLC31A1. Conclusion: METTL3 reduces SLC31A1 mRNA stability and down-regulates its expression in an m6A-YTHDF2- dependent manner, thereby inhibiting trophoblast migration and invasion.