Platelet-derived growth factor and transforming growth factor-beta modulate the expression of matrix metalloproteinases and migratory function of human airway smooth muscle cells.
BACKGROUND
Matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinase (TIMPs) have been suggested to be involved in the pathogenesis of asthma. Their expression in airway smooth muscle (ASM) cells could be involved in collagen turnover and migration of these cells and thus may contribute to airway remodelling.


OBJECTIVE
To examine the effect of pro-fibrotic growth factors TGF-beta and platelet-derived growth factor (PDGF) on the expression of MMPs/TIMPs in cultured human ASM cells and to examine the role of MMP in the migration of ASM cells.


METHODS
ASM cells were stimulated with TGF-beta and/or PDGF. Expression and activity of MMP-1, MMP-2, MMP-3, TIMP-1 and TIMP-2 were evaluated by quantitative RT-PCR, Western blot and zymography. Modified Boyden-chamber migration assay was performed to investigate the effect of secreted MMP-3 and TIMP-1 on ASM-cell migration.


RESULTS
PDGF strongly up-regulated the expression of MMP-1 at mRNA and protein levels. PDGF, when combined with TGF-beta, caused synergistic up-regulation of MMP-3. TIMP-1 was additively up-regulated by TGF-beta and PDGF. These growth factors had no effect on the expression of MMP-2 and TIMP-2. U0126, an extracellular signal-regulated kinase (ERK) pathway inhibitor, inhibited the up-regulation of MMP-1 by PDGF. The synergistic/additive up-regulation of MMP-3 and TIMP-1 was inhibited by U0126 and SB431542, a Smad pathway inhibitor. Supernatant from ASM cells in which MMP-3 production was knocked down by RNA interference showed a decreased migratory effect on ASM cells, whereas supernatant from cells with suppressed TIMP-1 expression resulted in increased migration.


CONCLUSIONS
Our results suggest that PDGF with/without TGF-beta could facilitate migration of ASM cells by modification of MMP-TIMP balance through the ERK pathway.
Ito
I
I
Meakins-Christie Laboratories, Department of Medicine, McGill University, Montreal, QC, Canada.
Fixman
E D
ED
Asai
K
K
Yoshida
M
M
Gounni
A S
AS
Martin
J G
JG
Hamid
Q
Q
D001549:Benzamides / Q000494:pharmacology; D002070:Butadienes / Q000494:pharmacology; D002465:Cell Movement / Q000187:drug effects*; D002478:Cells, Cultured; D004149:Dioxoles / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D048049:Extracellular Signal-Regulated MAP Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects*; D006801:Humans; D020935:MAP Kinase Signaling System / Q000187:drug effects; D020782:Matrix Metalloproteinases / Q000096:biosynthesis*; D032389:Myocytes, Smooth Muscle / Q000166:cytology / Q000201:enzymology*; D009570:Nitriles / Q000494:pharmacology; D010982:Platelet-Derived Growth Factor / Q000494:pharmacology*; D034622:RNA Interference; D051785:Smad Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism; D019715:Tissue Inhibitor of Metalloproteinase-1 / Q000096:biosynthesis; D019716:Tissue Inhibitor of Metalloproteinase-2 / Q000096:biosynthesis; D016212:Transforming Growth Factor beta / Q000494:pharmacology*; D015854:Up-Regulation / Q000187:drug effects
C459179:4-(5-benzo(1,3)dioxol-5-yl-4-pyridin-2-yl-1H-imidazol-2-yl)benzamide; D001549:Benzamides; D002070:Butadienes; D004149:Dioxoles; D004791:Enzyme Inhibitors; D009570:Nitriles; D010982:Platelet-Derived Growth Factor; D051785:Smad Proteins; D019715:Tissue Inhibitor of Metalloproteinase-1; D016212:Transforming Growth Factor beta; C113580:U 0126; D019716:Tissue Inhibitor of Metalloproteinase-2; D048049:Extracellular Signal-Regulated MAP Kinases; D020782:Matrix Metalloproteinases