Activation of AMPK by metformin inhibits TGF-β-induced collagen production in mouse renal fibroblasts

• Published in: Life sciences (1973) 2015-04, Vol.127, p.59-65
• Main Authors: Lu, Jiamei, Shi, Jianhua, Li, Manxiang, Gui, Baosong, Fu, Rongguo, Yao, Ganglian, Duan, Zhaoyang, Lv, Zhian, Yang, Yanyan, Chen, Zhao, Jia, Lining, Tian, Lifang
• Format: Article
• Language: English
• Subjects: Adenosine monophosphate-activated protein kinase (AMPK); Animals; Collagen; Collagen Type I - biosynthesis; Connective tissue growth factor (CTGF); Connective Tissue Growth Factor - biosynthesis; Cyclic AMP-Dependent Protein Kinases - metabolism; Enzyme Activation - drug effects; Fibroblasts - drug effects; Fibroblasts - metabolism; Hypoglycemic Agents - pharmacology; Kidney - cytology; Kidney - drug effects; Kidney - metabolism; Metformin - pharmacology; Mice; Mice, Inbred BALB C; Phosphorylation - drug effects; Primary Cell Culture; Renal fibroblasts; RNA, Small Interfering - pharmacology; Smad3 Protein - biosynthesis; Transforming Growth Factor beta - antagonists & inhibitors; Transforming Growth Factor beta - pharmacology; Transforming growth factor beta 1 (TGF-β1)
• ISSN: 0024-3205; 1879-0631
• DOI: 10.1016/j.lfs.2015.01.042

To clarify whether activation of adenosine monophosphate-activated protein kinase (AMPK) by metformin inhibits transforming growth factor beta (TGF-β)-induced collagen production in primary cultured mouse renal fibroblasts and further to address the molecular mechanisms. Primary cultured mouse renal fibroblasts were stimulated with TGF-β1 and the sequence specific siRNA of Smad3 or connective tissue growth factor (CTGF) was applied to investigate the involvement of these molecular mediators in TGF-β1-induced collagen type I production. Cells were pre-incubated with AMPK agonist metformin or co-incubated with AMPK agonist metformin and AMPK inhibitor Compound C before TGF-β1 stimulation to clarify whether activation of AMPK inhibition of TGF-β1-induced renal fibroblast collagen type I expression. Our results demonstrate that TGF-β1 time- and dose-dependently induced renal fibroblast collagen type I production; TGF-β1 also stimulated Smad3-dependent CTGF expression and caused collagen type I generation; this effect was blocked by knockdown of Smad3 or CTGF. Activation of AMPK by metformin reduced TGF-β1-induced collagen type I production by suppression of Smad3-driven CTGF expression. This study suggests that activation of AMPK might be a novel strategy for the treatment of chronic kidney disease (CKD) partially by inhibition of renal interstitial fibrosis (RIF).