[Connective tissue growth factor promotes the proliferation of myofibroblast through Erk-1/2 signaling pathway].
OBJECTIVE
To investigate the mechanism by which connective tissue growth factor (CTGF) enhances transforming growth factor-beta(1) (TGF-beta(1))-mediated myofibroblastic activation in renal interstitial fibroblast NRK-49F.


METHODS
NRK-49F cells were pretreated by TGF-beta(1) so that some cells transform into myofibroblasts, and then the cells were devided into vechile, CTGF treated group, TGF-beta(1) treated group, and PD98059 intervene group. The hallmark of myofibroblast, alpha-SMA immunostaining and marker of cellular proliferation, BrdU incorporation were determined by immunocytochemistry doublestaining. The protein level of alpha-SMA was determined by Western blot analysis.


RESULTS
CTGF induced a proliferative response in myofibroblast initiated by TGF-beta(1), whereas TGF-beta(1) had no action on proliferation. Although CTGF could not induce myofibroblastic activation in renal interstitial fibroblast, it upregulated the protein level of alpha-smooth muscle actin significantly in cells pretreated by TGF-beta1 (P < 0.05). Significant phosphorylation of Erk-1/2 was detected after incubation with CTGF for 30 min in the cells pretreated by TGF-beta(1), while TGF-beta(1) did not have this ability. Inhibition of Erk-1/2 activation by Mek kinase inhibitor PD98059 suppressed CTGF-mediated myofibroblasts proliferation and significantly down-regulated expression of alpha-SMA protein in cells pretreated by TGF-beta(1) (P < 0.05).


CONCLUSIONS
CTGF induced a proliferative response in TGF-beta(1)-initiated myofibroblasts, and this action is likely dependent on the activation of Erk-1/2 signaling pathway.
Huang
Hai-chang
HC
Division of Nephrology, Peking University First Hospital & Institute of Nephrology, Peking University, Beijing 100034, China.
Yang
Min
M
Li
Jing-zi
JZ
Wang
Hai-yan
HY
D000818:Animals; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D055513:Connective Tissue Growth Factor; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D005347:Fibroblasts / Q000166:cytology*; D017874:Immediate-Early Proteins / Q000494:pharmacology*; D036341:Intercellular Signaling Peptides and Proteins / Q000494:pharmacology*; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D051381:Rats; D015398:Signal Transduction; D016212:Transforming Growth Factor beta / Q000378:metabolism; D053773:Transforming Growth Factor beta1
C526316:CCN2 protein, rat; D017874:Immediate-Early Proteins; D036341:Intercellular Signaling Peptides and Proteins; C508962:Tgfb1 protein, rat; D016212:Transforming Growth Factor beta; D053773:Transforming Growth Factor beta1; D055513:Connective Tissue Growth Factor; D048049:Extracellular Signal-Regulated MAP Kinases; D048052:Mitogen-Activated Protein Kinase 3