Angiotensin II-mediated activation of fibrotic pathways through ERK1/2 in rat peritoneal mesothelial cells.
BACKGROUND
Peritoneal fibrosis is a common complication of peritoneal dialysis (PD) although the pathway involved is unclear. Of this article, angiotensin II (Ang II)-mediated upregulation of mitogen-activated protein kinase (MAPK) pathway as well as their downstream profibrotic genes including transforming growth factor (TGF)-beta1 and fibronectin (FN) was investigated.


METHODS
Rat peritoneal mesothelial cells (RPMCs) were obtained by enzymatic digestion from the colic omentum. After incubated with Ang II, real-time PCR, ELISA, and Western blot analysis were used to determine RPMCs cellular and secretory (supernatants) levels of TGF-beta1, FN, tissue inhibitor of metalloproteinase-1 (TIMP-1), and plasminogen activator inhibitor-1 (PAI-1) as well as the phosphorylation of extracellular signal-regulated kinase (ERK1/2), p38 MAPK, and stress-activated protein kinase/c-Jun NH(2)-terminal kinase (JNK). We also determined the downstream pathways using the specific inhibitors including PD98059 (ERK1/2), SB230580 (p38 MAPK), SP600125 (JNK), and losartan [Ang II type-1 (AT1] receptor blocker).


RESULTS
Ang II increased mRNA and protein levels of TGF-beta1, FN, TIMP-1, and PAI-1 in a time- and dose-dependent manner in RPMCs. Ang II induced a 1.5-2-fold increase in both mRNA and protein levels of the above molecules at 10 nmol/L. Ang II also upregulated the phosphorylation of ERK1/2 and p38 but not of JNK. Finally, inhibition of either AT1 or ERK1/2 was able to suppress Ang II-induced expression of FN.


CONCLUSIONS
In cultured RPMCs, Ang II upregulated profibrotic signaling pathways through AT1-mediated ERK1/2 phosphorylation.
Xie
Jing-Yuan
JY
Department of Nephrology, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, PR China.
Chen
Nan
N
Ren
Hong
H
Wang
Wei-Ming
WM
D000804:Angiotensin II / Q000502:physiology*; D000818:Animals; D002478:Cells, Cultured; D004847:Epithelial Cells / Q000502:physiology*; D008297:Male; D048052:Mitogen-Activated Protein Kinase 3 / Q000502:physiology*; D056627:Peritoneal Fibrosis / Q000209:etiology*; D010537:Peritoneum / Q000166:cytology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction
D000804:Angiotensin II; D048052:Mitogen-Activated Protein Kinase 3