METTL3-Mediated m6A Modification of ACTR2 Promotes Trophoblast Cell Growth, Migration and Invasion in Unexplained...

Actin-related protein 2 (ACTR2) is an important factor in the regulation of cell function and is considered to be a potential therapeutic target for RSA. However, whether ACTR2 mediates unexplained RSA by regulating trophoblast cell function remains unclear. The expression of ACTR2 and methyltransferase-like 3 (METTL3) in the villous tissues of unexplained RSA patients and trophoblast cells (HTR-8/SVneo) was detected by qRT-PCR or western blot. Cell proliferation, apoptosis, invasion, and migration were examined by CCK8 assay, EdU assay, flow cytometry, transwell assay and wound healing assay. MeRIP assay, RIP assay or RNA pull-down assay was used to confirm the interaction between METTL3/YTHDF2 and ACTR2. The regulation of METTL3/YTHDF2 on the mRNA stability of ACTR2 was confirmed by actinomycin D assay. β-catenin and Wnt3A protein levels were tested by western blot. ACTR2 was downregulated in unexplained RSA patients, and its overexpression promoted HTR-8/SVneo cell proliferation, migration, invasion and reduced apoptosis. However, ACTR2 knockdown suppressed HTR-8/SVneo cell functions. ACTR2 had m6A modification sites, and METTL3 could enhance the m6A modification of ACTR2 to reduce its mRNA stability and expression. METTL3-mediated the m6A modification of ACTR2 could be recognized by m6A reader YTHDF2. METTL3 knockdown increased HTR-8/SVneo cell growth, migration and invasion, as well as β-catenin and Wnt3A protein levels, while these effects could be reversed by ACTR2 silencing. METTL3 might inhibit trophoblast cell functions by inactivating Wnt/β-catenin pathway through enhancing the m6A modification of ACTR2, providing a novel target for unexplained RSA.