DDX39B drives the m6A modification of LDHA to promote trophoblast proliferation.

Preeclampsia (PE), a hypertensive disorder unique to pregnancy, is linked to impaired trophoblast function. DEAD-box helicase 39B (DDX39B) plays key roles in embryonic development. This study investigated its role in regulating trophoblast biology during PE progression. We conducted functional assays using CCK-8, clone formation, EdU, Transwell, Wound healing and TUNEL in the HTR-8/SVneo trophoblast cells. The interaction between Wilms tumor 1-associating protein (WTAP) and DDX39B was analyzed by Co-IP assay. RIP assay or RNA pull down were used to assess the association between the ELAV-like RNA-binding protein 1 (ELAVL1)/WTAP and L-lactate dehydrogenase A (LDHA) mRNA. Additionally, MeRIP assay was employed to evaluate m6A levels on LDHA transcripts. Overexpression of DDX39B promoted the proliferation and migration of trophoblast cells and suppressed cells apoptosis, while DDX39B knockdown had the opposite result. In addition, WTAP knockdown reversed the promoting effects of DDX39B overexpression on trophoblast proliferation and migration. Mechanistically, DDX39B promoted post-translational stabilization of WTAP by directly interacting with WTAP protein. WTAP enhanced the m6A methylation of LDHA mRNA by recruiting ELAVL1. As expected, LDHA knockdown abrogated the pro-proliferative and anti-apoptotic effects of WTAP overexpression on trophoblasts. Our findings established a novel DDX39B/WTAP/m6A/LDHA regulatory axis, wherein DDX39B acted as an RNA-binding protein to stabilize WTAP, enhancing LDHA expression and promoting trophoblast proliferation, migration, and survival. Dysregulation of this pathway might contribute to PE pathogenesis, offering new avenues for targeted therapies.