Role of the microRNA-214/Bax axis in the progression of acute liver failure

Acute liver failure (ALF) is a fatal liver disease characterized by severe hepatocyte destruction. MicroRNAs (miRNAs/miRs) have been reported to serve a key role in a number of liver diseases. Therefore, the aim of the present study was to investigate the role and underlying mechanism of miR-214 in ALF. ALF murine and hepatocyte models were established using D-galactosamine (D-GalN) and lipopolysaccharide (LPS) or D-GalN + tumor necrosis factor (TNF)-α, respectively. The expression levels of miR-214 and Bax were detected by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and/or western blotting. Furthermore, an automatic biochemical analyzer was used to measure the levels of aspartate aminotransferase (AST) or alanine aminotransferase (ALT). The levels of TNF-α and interleukin (IL)-6 were detected by ELISA and RT-qPCR. In addition, TUNEL staining and flow cytometry were used to analyze cell apoptosis, and the protein expression of caspase-3 was determined by western blotting. It was identified that the levels of AST and ALT were increased and that hepatocyte apoptosis was enhanced in the D-GalN/LPS-stimulated group compared with the control. Furthermore, higher expression of caspase-3 was observed in the D-GalN/LPS-stimulated group. In addition, it was demonstrated that miR-214 was downregulated, while Bax was upregulated in D-GalN/LPS-stimulated mice and D-GalN/TNF-α-stimulated BNLCL2 cells. Moreover, in D-GalN/TNF-α-stimulated BNLCL2 cells, miR-214 overexpression suppressed apoptosis and decreased TNF-α and IL-6 levels, and these effects were reversed by the Bax plasmid. It was also identified that overexpression of miR-214 significantly decreased Bax mRNA and protein expression levels in vitro. Collectively, the present results suggested that miR-214 inhibited hepatocyte apoptosis during ALF development via targeting Bax, thus indicating that miR-214 may be a potential target for ALF treatment.