Free fatty acid-induced DDX3 inhibits autophagy via miR-141 upregulation in diet-induced MASLD mice model system.

Abstract

Introduction and objectives: Metabolic dysfunction-associated steatotic liver disease (MASLD) is one of the primary causes of chronic liver disease and may lead to liver cirrhosis and hepatocellular carcinoma. Recent reports suggested that DEAD-box RNA helicase (DDX3) acts as a sensor of free fat accumulation and may modulate the pathogenesis via miRNAs. Hence, we hypothesized that DDX3 might modulate MASLD progression via miRNA-141-mediated inhibition of Sirt-1 and autophagy.

Materials and methods: RNA and total protein were isolated from free fatty acid-treated HepG2 cells or CDAA-fed C57BL/6 mice (6 mice per group) for 6, 18, 32, or 54 weeks. The cells were transfected with DDX3 or miR-141 or siRNA to DDX3, and Western blots for autophagy markers were performed.

Results: The FFAs induced the DDX3 and miRNA-141 expression, while downregulating Sirt-1, beclin-1, Atg7, and LC3-II. Overexpression of DDX3 resulted in increased miRNA-141. Overexpression of DDX3 or miRNA-141 downregulated Sirt-1 expression and autophagy marker proteins, while these effects were reversed with siRNA to DDX3. The expression of both DDX3 and miRNA-141 was significantly increased, while autophagy markers were downregulated in CDAA-fed mice.

Conclusions: These results confirmed that FFA-induced DDX3 induced the expression of miRNA-141, which in turn targeted Sirt-1 and decreased autophagy.