WTAP/YTHDC1-mediated m6A modification of P4HA1 suppresses hepatic gluconeogenesis and ameliorates MASLD by activating AKT signaling.

Abstract

Metabolic dysfunction-associated steatotic liver disease (MASLD) is a global metabolic epidemic with limited therapeutic options. Prolyl 4-hydroxylase subunit alpha 1 (P4HA1) has been implicated in glucose metabolism, but its functional role and regulatory mechanisms in MASLD remain unknown. In this study, we established a high-fat diet (HFD)-induced MASLD mouse model and a free fatty acid (FFA)-induced steatosis model in HepG2 cells. We found that P4HA1 was significantly downregulated in both HFD-fed mouse livers and FFA-treated HepG2 cells. P4HA1 overexpression ameliorated HFD-induced glucose intolerance, insulin resistance, and hepatic steatosis. Mechanistically, WTAP-mediated m6A modification of P4HA1 mRNA, recognized by the m6A reader YTHDC1, stabilized P4HA1 transcripts. Moreover, P4HA1 directly bound the PH domain of AKT, enhanced AKT phosphorylation at Thr308 and Ser473, promoted FoxO1 nuclear exclusion, and suppressed gluconeogenic gene transcription. In vivo WTAP overexpression restored P4HA1 expression and AKT activity, recapitulating the protective effects. Collectively, this study establishes a novel WTAP/YTHDC1-m6A-P4HA1-AKT signaling axis in MASLD pathogenesis, identifies P4HA1 as a protective metabolic regulator whose downregulation promotes excessive gluconeogenesis and lipid accumulation, and suggests that targeting this axis may represent a promising therapeutic strategy for MASLD.