Effects of microRNA-106b on hepatic gluconeogenesis and its underlying mechanism

Abstract

Objective: To investigate the potential effects of microRNA-106b (miR-106b) on gluconeogenesis in normal human liver cell line L02 and its underlying mechanisms. Methods: Normal human liver L02 cells were cultured in DMEM containing 10% FBS and transfected with 20 nmol/L of miR-106b mimic or antagomiR-106b, respectively. Twenty-four hours later after transfection, Western blot was performed to detect the levels of proteins or phosphorylated proteins. Quantitative RT-PCR was carried out to measure the mRNA expressions of gluconeogenesis-related genes. Glucose Assay Kit was used to detect the glucose contents in the medium. Results: MiR-106b mimic significantly increased the protein abundances of phosphoenolpyruvate carboxykinase (PEPCK) and glucose-6-phosphatase (G6Pase)(P＜0.01,P＜0.01, respectively), enhanced the mRNA expression of phosphoenolpyruvate carboxykinase 1 (PCK1) (P＜0.01), and decreased the mRNA level of glucokinase (GCK) (P＜0.01). AntagomiR-106b dramatically reduced the protein levels of PEPCK and G6Pase (P＜0.01,P＜0.01, respectively), suppressed the mRNA level of PCK1 (P＜0.01), and increased the mRNA level of GCK(P＜0.01). In addition,miR-106b mimic or antagomiR-106b significantly reduced or enhanced the protein levels of signal transducer and activator of transcription 3 (STAT3)(P＜0.01,P＜0.01, respectively).The inhibition of STAT3 by its specific inhibitor abolished the inhibitory effects of antagomiR-106b on hepatic gluconeogenesis. Conclusion: miR-106b increases hepatic gluconeogenesis by inhibiting the STAT3 signaling pathway.