Interleukin-lβ induces migration of rat arterial smooth muscle cells through a mechanism involving increased matrix metalloproteinase-2 activity.
BACKGROUND
Interleukin-lβ (IL-lβ) is associated with vascular smooth muscle cell (VSMC) migration during neointimal formation following arterial injury, of which matrix metalloproteinase-2 (MMP-2) may have an important role. We investigated whether IL-lβ stimulated migration and MMP-2 production in VSMC, and, if so, whether migration correlated with MMP-2 activity.


METHODS
Modified Boyden chamber assay quantified cultured rat aorta VSMC migration. Methyl-thiazolyl-tetrazolium assay assessed cell growth. Gelatin zymography and Western blotting determined MMP-2 activity and protein levels, respectively.


RESULTS
IL-lβ (0.1 - 10 ng/mL) induced migration of VSMC in a concentration-dependent manner without cell proliferation. VSMC released increasing levels of active MMP-2 in a dose-response fashion at IL-1β 1-10 ng/mL (P < 0.05) while significantly increased levels of latent MMP-2 (pro-MMP-2) were attained more gradually (10 ng/mL, P < 0.05). There was a dose-dependent increase in the ratio of active MMP-2 to pro-MMP-2 in response to IL-1β (1-10 ng/mL, P < 0.05), suggesting extracellular activation of pro-MMP-2. Protein levels on Western blot paralleled enzyme activity, with the synthesis of more active MMP-2 than pro-MMP-2 in response to IL-1β. IL-lβ-stimulated VSMC migration was significantly attenuated by both the pan-selective MMP inhibitor GM6001 and cis-9-octadecenoyl-N-hydroxylamide, a MMP-2-selective inhibitor.


CONCLUSIONS
IL-lβ increases MMP-2 activity in VSMC through increased protein synthesis and activation of pro-MMP-2. VSMC migration induced by IL-lβ requires active MMP-2. IL-lβ may play a role in arterial remodeling following injury.
Wang
Zhongbiao
Z
Department of Surgery, Mercer University School of Medicine and Medical Center of Central Georgia, Macon, Georgia 31207, USA. wang_z@mercer.edu
Kong
Lingwei
L
Kang
Jing
J
Vaughn
Danny M
DM
Bush
Geary D
GD
Walding
Anna L
AL
Grigorian
Arthur A
AA
Robinson
Joe S
JS
Nakayama
Don K
DK
D000818:Animals; D001011:Aorta / Q000166:cytology; D002465:Cell Movement / Q000187:drug effects* / Q000502:physiology; D002478:Cells, Cultured; D004151:Dipeptides / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D053583:Interleukin-1beta / Q000494:pharmacology*; D020778:Matrix Metalloproteinase 2 / Q000187:drug effects / Q000378:metabolism*; D061965:Matrix Metalloproteinase Inhibitors; D023421:Models, Animal; D009131:Muscle, Smooth, Vascular / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism*; D011480:Protease Inhibitors / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology
D004151:Dipeptides; D053583:Interleukin-1beta; D061965:Matrix Metalloproteinase Inhibitors; C078131:N-(2(R)-2-(hydroxamidocarbonylmethyl)-4-methylpentanoyl)-L-tryptophan methylamide; D011480:Protease Inhibitors; D020778:Matrix Metalloproteinase 2