Oncostatin M stimulates tissue inhibitor of metalloproteinase-1 via a MEK-sensitive mechanism in human myofibroblasts.
OBJECTIVE
We previously showed that in cultured human myofibroblasts (hMFBs), Oncostatin M (OSM)-stimulated collagen accumulation is associated with increased tissue inhibitor of metalloproteinase (TIMP)1 message. However, the mechanism is unknown.


METHODS
hMFBs were isolated by outgrowth from cirrhotic liver explants and cultured. Using OSM (10 ng/ml) stimulation, with and without PD98059 (PD, a specific mitogen-activated protein kinase/extracellular signal-related kinase (MEK) inhibitor), we measured: TIMP-1 protein in culture medium by Western blot, TIMP-1 mRNA levels and stability by Northern analysis, TIMP-1 promoter activity (including transcription site mutation analysis), DNA binding activity to nuclear proteins by electrophoretic mobility shift assay (EMSA), and total and phosphorylated MAP kinase in hMFB extracts by Western blot.


RESULTS
OSM stimulation of hMFBs increased TIMP-1 protein production 1.69-fold, TIMP-1 mRNA levels 2.36-fold, promoter activity 2.22-fold, TIMP-1 message stability, and phosphorylation of mitogen-activated protein kinase (MAPK). PD inhibited OSM-mediated stimulation of TIMP-1 protein, mRNA, promoter activity, phosphorylation of MAPK, and TIMP-1 message stability. An SP-1 transcription site of the TIMP-1 promoter is essential for OSM induction of TIMP-1 promoter activity. EMSA demonstrates that this site binds to transcriptional factors SP-1 and SP-3.


CONCLUSIONS
OSM stimulates the TIMP-1 axis in hMFBs in vitro via a MEK-MAP kinase cascade.
Sohara
Naondo
N
Division of Gastroenterology and Hepatology, Department of Medicine, Medical University of South Carolina, 96 Jonathan Lucas Street, Suite 210, Charleston, SC 29425, USA.
Trojanowska
Maria
M
Reuben
Adrian
A
D002478:Cells, Cultured; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005347:Fibroblasts / Q000166:cytology / Q000201:enzymology*; D005419:Flavonoids / Q000494:pharmacology; D015870:Gene Expression / Q000187:drug effects; D006131:Growth Inhibitors / Q000494:pharmacology*; D006801:Humans; D008099:Liver / Q000166:cytology; D048728:MAP Kinase Kinase Kinase 1; D020935:MAP Kinase Signaling System / Q000187:drug effects / Q000502:physiology; D053683:Oncostatin M; D010455:Peptides / Q000494:pharmacology*; D010766:Phosphorylation; D011401:Promoter Regions, Genetic / Q000187:drug effects / Q000235:genetics; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D012333:RNA, Messenger / Q000032:analysis; D019715:Tissue Inhibitor of Metalloproteinase-1 / Q000235:genetics*
D004791:Enzyme Inhibitors; D005419:Flavonoids; D006131:Growth Inhibitors; C508351:OSM protein, human; D010455:Peptides; D012333:RNA, Messenger; D019715:Tissue Inhibitor of Metalloproteinase-1; D053683:Oncostatin M; D017346:Protein Serine-Threonine Kinases; D048728:MAP Kinase Kinase Kinase 1; C482576:MAP3K1 protein, human; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one