Metformin inhibits collagen production in rat biliary fibroblasts: the molecular signaling mechanism / 南方医科大学学报

ABSTRACT

OBJECTIVE@#To clarify the molecular signaling mechanism underlying the inhibitory effect of metformin on transforming growth factor-β1 (TGF-β1)-stimulated collagen I production in rat biliary fibroblasts.@*METHODS@#Primary biliary fibroblasts were isolated under aseptic condition from 50 Sprague-Dawley rats (half male and half female), and microscopic observation identified no obvious difference in the morphology or viability of the cells from rats with different sexes or body weight. The cells were treated with TGF-β1 (10 ng/mL), Smad3 siRNA+TGF-β1, CTGF siRNA+TGF-β1, metformin (10 mmol/L)+ TGF-β1, or Compound C (10 μmol/L)+metformin+TGF-β1. The expressions of CTGF and collagen I in the treated cells were determined using ELISA kit or Western blotting; the phorsphorylated and total Smad3 and AMPK expressions were detected using immunoblotting.@*RESULTS@#TGF-β1 time- and dose-dependently induced collagen I production in rat biliary fibroblasts. The activated AMPK by metformin dose-dependently inhibited TGF-β1-induced collagen I production. Pre-incubation of cells with the AMPK inhibitor Compound C restored the inhibitory effect of AMPK on TGF-β1-induced collagen I secretion ( < 0.01). Activation of AMPK by metformin significantly reduced TGF-β1-induced collagen I production by suppressing Smad3-driven CTGF expression ( < 0.01), and the application of Compound C reversed such changes in the fibroblasts ( < 0.01).@*CONCLUSIONS@#Metformin inhibits TGF-β1-stimulated collagen I production by activating AMPK and inhibiting Smad3- driven CTGF expression in rat biliary fibroblasts.