Regulation of matrix metalloproteinase MT1-MMP/MMP-2 in cardiac fibroblasts by TGF-beta1 involves furin-convertase.
OBJECTIVE
Heart failure is characterized by an imbalance of matrix synthesis/turnover, finally resulting in fibrosis. Cardiac myocytes and fibroblasts play a pivotal role in the remodeling process. Cardiac remodeling involves the expression of TGF-beta1 and matrix metalloproteinases (MMPs) in cardiac fibroblasts (CFBs). Furin, a subtilisin/kexin-like proprotein convertase (PC), activates TGF-beta1 and membrane-bound MT1-MMP, which facilitates pro-gelatinase A (MMP-2) activation. Even though several reports identified TGF-beta1 as a pro-fibrotic cytokine in the heart, it increases MMP-activity and cell migration/invasion in several cell types. The present study was done to investigate the contribution of TGF-beta1 and furin to CFBs MMP-activity and motility.


RESULTS
Stimulation of CFBs from adult Sprague-Dawley rats with TGF-beta1 (20 ng/ml) induced furin, but had no effect on the closely related PC5. Inhibition of furin inhibited angiotensin II-induced TGF-beta1 activation, indicating that TGF-beta1 amplifies its activating convertase in CFBs. Pretreatment of CFBs with TGF-beta1 (20 ng/ml, 24 h) increased their migration by about two-fold (p<0.05), which was accompanied by an enhanced expression and activity of MT1-MMP and MMP-2. Brefeldin A (BFA), a Golgi-disturbing agent, inhibited MT1-MMP activation, indicating that it occurs in the trans-Golgi network (TGN), where furin is concentrated and colocalized with MT1-MMP. Inhibition of furin significantly inhibited TGF-beta1-induced MT1-MMP/MMP-2 activation. Furthermore, inhibition of furin attenuated TGF-beta1-enhanced migration on gelatin-coated membranes (p<0.05). This was comparable to the effects of the MMP-inhibitor GM6001, pointing out that MMPs are major mediators of TGF-beta1-enhanced CFB motility.


CONCLUSIONS
We demonstrate that TGF-beta1 induces MMP-activity in CFBs, thereby facilitating CFBs motility. Furthermore, TGF-beta1 amplifies its activating convertase furin, which is also required for MT1-MMP/MMP-2 activation in CFBs. Thus, furin is central for TGF-beta1 and MT1-MMP activation and might be a novel target in cardiac remodeling.
Stawowy
Philipp
P
Department of Medicine/Cardiology, Deutsches Herzzentrum Berlin, D-13353 Berlin, Germany. stawowy@dhzb.de
Margeta
Christian
C
Kallisch
Heike
H
Seidah
Nabil G
NG
Chrétien
Michel
M
Fleck
Eckart
E
Graf
Kristof
K
D000818:Animals; D020126:Brefeldin A / Q000494:pharmacology; D002465:Cell Movement / Q000187:drug effects; D002478:Cells, Cultured; D004151:Dipeptides / Q000494:pharmacology; D005347:Fibroblasts / Q000378:metabolism / Q000473:pathology; D045683:Furin / Q000378:metabolism; D006056:Golgi Apparatus / Q000187:drug effects; D008297:Male; D020781:Matrix Metalloproteinase 1 / Q000378:metabolism; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism; D061965:Matrix Metalloproteinase Inhibitors; D020782:Matrix Metalloproteinases / Q000378:metabolism*; D009206:Myocardium / Q000201:enzymology*; D043484:Proprotein Convertases / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D016212:Transforming Growth Factor beta / Q000494:pharmacology*
D004151:Dipeptides; D061965:Matrix Metalloproteinase Inhibitors; C078131:N-(2(R)-2-(hydroxamidocarbonylmethyl)-4-methylpentanoyl)-L-tryptophan methylamide; D016212:Transforming Growth Factor beta; D020126:Brefeldin A; D043484:Proprotein Convertases; D045683:Furin; D020782:Matrix Metalloproteinases; D020778:Matrix Metalloproteinase 2; D020781:Matrix Metalloproteinase 1