16868306

pubmed:Citation

6

Epithelial-to-mesenchymal transition (EMT) has emerged as a critical event in the pathogenesis of tubulointerstitial fibrosis. EMT is typically induced by transforming growth factor-beta1 (TGF-beta1) and inhibited by hepatocyte growth factor (HGF). The present study was undertaken to evaluate the potential role of cyclooxygenase (COX)-2-derived PGE2 in regulation of EMT in cultured Madin-Darby canine kidney (MDCK) cells, in the setting of HGF treatment. Exposure to 50 ng/ml HGF significantly induced COX-2 protein expression and PGE2 release, whereas other growth factors, including epidermal growth factor, the insulin-like growth factor I protein, platelet-derived growth factor-BB, and TGF-beta1, had no effects on COX-2 expression or PGE2 release. COX-2 induction by HGF was preceded by activation of ERK1/2, and an ERK1/2-specific inhibitor, U-0126 (10 microM), completely abolished HGF-induced COX-2 expression. Exposure of MDCK cells to 10 ng/ml TGF-beta1 for 72 h induced EMT as evidenced by conversion to the spindle-like morphology, loss of E-cadherin, and activation of alpha-smooth muscle actin. In contrast, treatment with 1 microM PGE2 completely blocked EMT, associated with a significant elevation of intracellular cAMP and complete blockade of TGF-beta1-induced oxidant production. cAMP-elevating agents, including 8-Br-cAMP, forskolin, and IBMX, inhibited EMT and associated oxidative stress induced by TGF-beta1, but inhibition of cAMP pathway with Rp-cAMP, the cAMP analog, and H89, the protein kinase A (PKA) inhibitor, did not block the effect of PGE2. The effect of HGF on EMT was inhibited by approximately 50% in the presence of a COX-2 inhibitor SC-58635 (10 microM). Therefore, our data suggest that PGE2 inhibits EMT via inhibition of oxidant production and COX-2-derived PGE2 partially accounts for the antifibrotic effect of HGF.

eng

IM

MEDLINE

1931-857X

Print

NLM

F1323-31

pubmed-meshheading:16868306-Actins, pubmed-meshheading:16868306-Animals, pubmed-meshheading:16868306-Cadherins, pubmed-meshheading:16868306-Cell Line, pubmed-meshheading:16868306-Cyclooxygenase 2, pubmed-meshheading:16868306-Cyclooxygenase Inhibitors, pubmed-meshheading:16868306-Dinoprostone, pubmed-meshheading:16868306-Dogs, pubmed-meshheading:16868306-Drug Interactions, pubmed-meshheading:16868306-Enzyme Activation, pubmed-meshheading:16868306-Epithelial Cells, pubmed-meshheading:16868306-Fibrosis, pubmed-meshheading:16868306-Hepatocyte Growth Factor, pubmed-meshheading:16868306-Kidney Failure, Chronic, pubmed-meshheading:16868306-Kidney Tubules, pubmed-meshheading:16868306-MAP Kinase Signaling System, pubmed-meshheading:16868306-Mesoderm, pubmed-meshheading:16868306-Mitogen-Activated Protein Kinase 1, pubmed-meshheading:16868306-Mitogen-Activated Protein Kinase 3, pubmed-meshheading:16868306-Pyrazoles, pubmed-meshheading:16868306-Sulfonamides, pubmed-meshheading:16868306-Transforming Growth Factor beta1

Prostaglandin E2 is a potent inhibitor of epithelial-to-mesenchymal transition: interaction with hepatocyte growth factor.

Journal Article, Research Support, N.I.H., Extramural