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


METHODS
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.


RESULTS
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.


CONCLUSIONS
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).
Department of Nephrology Diseases, The Second Affiliated Hospital of Medical College, Xi'an Jiaotong University, Xi'an, Shaanxi 710004, PR China.
Jiamei
J
Lu
Department of Hepatobiliary Surgery, The First Affiliated Hospital of Medical College, Xi'an Jiaotong University, Xi'an, Shaanxi 710061, PR China.
Jianhua
J
Shi
Department of Respiratory Diseases, The Second Affiliated Hospital of Medical College, Xi'an Jiaotong University, Xi'an, Shaanxi 710004, PR China.
Manxiang
M
Li
Department of Nephrology Diseases, The Second Affiliated Hospital of Medical College, Xi'an Jiaotong University, Xi'an, Shaanxi 710004, PR China. Electronic address: lu-jia1980@163.com.
Baosong
B
Gui
Department of Nephrology Diseases, The Second Affiliated Hospital of Medical College, Xi'an Jiaotong University, Xi'an, Shaanxi 710004, PR China.
Rongguo
R
Fu
Department of Nephrology Diseases, The Second Affiliated Hospital of Medical College, Xi'an Jiaotong University, Xi'an, Shaanxi 710004, PR China.
Ganglian
G
Yao
Department of Nephrology Diseases, The Second Affiliated Hospital of Medical College, Xi'an Jiaotong University, Xi'an, Shaanxi 710004, PR China.
Zhaoyang
Z
Duan
Department of Nephrology Diseases, The Second Affiliated Hospital of Medical College, Xi'an Jiaotong University, Xi'an, Shaanxi 710004, PR China.
Zhian
Z
Lv
Department of Nephrology Diseases, The Second Affiliated Hospital of Medical College, Xi'an Jiaotong University, Xi'an, Shaanxi 710004, PR China.
Yanyan
Y
Yang
Department of Nephrology Diseases, The Second Affiliated Hospital of Medical College, Xi'an Jiaotong University, Xi'an, Shaanxi 710004, PR China.
Zhao
Z
Chen
Department of Nephrology Diseases, The Second Affiliated Hospital of Medical College, Xi'an Jiaotong University, Xi'an, Shaanxi 710004, PR China.
Lining
L
Jia
Department of Nephrology Diseases, The Second Affiliated Hospital of Medical College, Xi'an Jiaotong University, Xi'an, Shaanxi 710004, PR China.
Lifang
L
Tian
D000818:Animals; D024042:Collagen Type I / Q000096:biosynthesis*; D055513:Connective Tissue Growth Factor / Q000096:biosynthesis; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism*; D004789:Enzyme Activation / Q000187:drug effects; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism*; D007004:Hypoglycemic Agents / Q000494:pharmacology*; D007668:Kidney / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D008687:Metformin / Q000494:pharmacology*; D051379:Mice; D008807:Mice, Inbred BALB C; D010766:Phosphorylation / Q000187:drug effects; D061251:Primary Cell Culture; D034741:RNA, Small Interfering / Q000494:pharmacology; D051900:Smad3 Protein / Q000096:biosynthesis; D016212:Transforming Growth Factor beta / Q000037:antagonists & inhibitors* / Q000494:pharmacology
C526318:CCN2 protein, mouse; D024042:Collagen Type I; D007004:Hypoglycemic Agents; D034741:RNA, Small Interfering; D051900:Smad3 Protein; C497791:Smad3 protein, mouse; D016212:Transforming Growth Factor beta; D055513:Connective Tissue Growth Factor; D008687:Metformin; D017868:Cyclic AMP-Dependent Protein Kinases
AMPK (PubChem CID: 16760291); Adenosine monophosphate-activated protein kinase (AMPK); Collagen; Connective tissue growth factor (CTGF); Renal fibroblasts; TGF-β1 (PubChem CID: 56842206); Transforming growth factor beta 1 (TGF-β1)