Transforming growth factor-beta 1 promotes contraction of collagen gel by cardiac fibroblasts through their differentiation into myofibroblasts.
Myofibroblasts and transforming growth factor-beta 1 (TGF-beta 1) are key elements of cardiac tissue fibrosis development. The aim of this study was to determine whether the ability of TGF-beta 1 to affect the contractile activity of cardiac fibroblasts depends on their differentiation into myofibroblasts. Cardiac fibroblasts (from male adult Wistar rats) from passage 2 were therefore cultured to confluency and incubated on a hydrated collagen gel, both with and without TGF-beta 1 (0, 20, 40, 100, 200, 400 or 600 pmol/l), for 1, 2 and 3 days in a Dulbecco's Modified Eagle's Medium (DMEM) without fetal bovine serum (FBS). Growing cultures of cardiac fibroblasts were obtained by incubating second-passage fibroblasts in DMEM with 10% FBS with or without TGF-beta 1 (0 to 600 pmol/l) for 6 days. These fibroblasts were then further incubated on the collagen gel for 1, 2 and 3 days in DMEM without FBS. TGF-beta 1 dose-dependently increased the contraction of collagen gel mediated by cardiac fibroblasts, either added directly to the gel or after growing of the cardiac fibroblasts in the presence of TGF-beta 1 for 6 days, reaching a maximal effect at 100 pmol/l TGF-beta 1. In both culturing conditions, TGF-beta 1 also stimulated the [3H]-thymidine incorporation and the total protein content in the cardiac fibroblasts in the collagen gel lattice. TGF-beta 1 dose-dependently induced an increase in alpha-smooth muscle actin, a marker of myofibroblasts, in both culturing conditions. The TGF-beta 1-induced reduction of area of the collagen gel was negatively correlated to the TGF-beta 1-evoked appearance of alpha-smooth muscle actin in the collagen gel matrix. TGF-beta 1 increased the contractile activity of adult rat cardiac fibroblasts and their ability to differentiate into myofibroblasts. Because contractile activity was correlated with differentiation, the influence of TGF-beta 1 on cardiac fibroblast-induced collagen gel contraction may depend on the promotion of myofibroblast differentiation.
Hypertension and Cardiovascular Rehabilitation Unit, Department of Molecular and Cardiovascular Research, University of Leuven, K.U. Leuven, Belgium. paul.lijnen@med.kuleuven.ac.be
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Lijnen
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Petrov
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Rumilla
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Fagard
D000199:Actins / Q000096:biosynthesis; D000818:Animals; D015153:Blotting, Western; D002454:Cell Differentiation / Q000187:drug effects*; D002478:Cells, Cultured; D003094:Collagen; D004247:DNA / Q000096:biosynthesis; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D005782:Gels; D008297:Male; D009200:Myocardial Contraction / Q000187:drug effects*; D009206:Myocardium / Q000166:cytology*; D051381:Rats; D017208:Rats, Wistar; D013936:Thymidine / Q000378:metabolism; D016212:Transforming Growth Factor beta / Q000378:metabolism / Q000494:pharmacology*; D053773:Transforming Growth Factor beta1
D000199:Actins; D005782:Gels; C508962:Tgfb1 protein, rat; D016212:Transforming Growth Factor beta; D053773:Transforming Growth Factor beta1; D003094:Collagen; D004247:DNA; D013936:Thymidine