METTL3-dependent m6A modification of ERO1A mRNA regulates trophoblast migration and invasion in early-onset severe preeclampsia.

INTRODUCTION

N6-methyladenosine (m6A) is a common epigenetic modification of eukaryotic RNA that plays a vital role in the physiological and pathogenesis of preeclampsia (PE). Methyltransferase-like 3 (METTL3) is a methyltransferase of m6A. However, the function of METTL3 in early onset severe pre-eclampsia (EO-sPE) remains to be studied.

METHODS

Immunohistochemistry, qRT-PCR, and western blotting, as well as colorimetric RNA m6A methylation quantification assay, were used to assess the METTL3 expression level and global RNA m6A modification level in placental tissues collected from females with normal pregnancy and EO-sPE. Loss or gain-of-function tests were performed to assess the effects of METTL3 on cell proliferation, migration, and invasion. Transcriptome sequencing, Gene ontology (GO) functional and Kyoto encyclopedia of genes and genomes (KEGG) pathway analyses, MeRIP-qPCR, qRT-PCR, and western blotting were conducted to explore the downstream genes.

RESULTS

METTL3 expression and Global RNA m6A methylation were significantly increased in EO-sPE placental tissues. In vitro studies showed that knockdown of METTL3 promoted trophoblast proliferation, migration, and invasion; conversely, overexpression of METTL3 showed the opposite effect. We further demonstrated that METTL3 knockdown epigenetically elevated endoplasmic reticulum oxidoreductase 1 alpha (ERO1A) expression via an m6A-dependent mechanism. ERO1A inhibition effectively diminished the increase in trophoblast migration and invasion induced by METTL3 depletion in HTR-8/SVneo cells.

CONCLUSIONS

The m6A methyltransferase METTL3 may affect the biological behavior of trophoblast cells by negatively regulating the downstream gene ERO1A, suggesting that METTL3 might be associated with the etiology of EO-sPE.