Differential effects of transforming growth factor-beta 1 and phorbol myristate acetate on cardiac fibroblasts. Regulation of fibrillar collagen mRNAs and expression of early transcription factors.
Cardiac fibroblasts are responsible for synthesis and deposition of fibrillar collagen types I and III. Transforming growth factor-beta 1 (TGF-beta 1) has been proved to increase collagen biosynthesis in various systems, both in vivo and in vitro. We have investigated the effect of TGF-beta 1 on collagen gene expression in cultured cardiac fibroblasts and have compared this effect with that of a mitogenic agent, phorbol myristate acetate (PMA). The regulation of collagen types I and III gene expression was examined by using cDNA probes to rat alpha 2 (I) and mouse alpha 1 (III) procollagens. Quiescent cultured cardiac fibroblasts from rabbit heart were treated with TGF-beta 1 (10-15 ng/ml) and PMA (200 ng/ml). After 24 hours of treatment with TGF-beta 1, the abundance of mRNA for pro-alpha 2 (I) and pro-alpha 1 (III) collagens was increased by 112% (p less than 0.001) and 97% (p = 0.05), respectively, in treated fibroblasts compared with untreated cells. However, PMA-treated cells showed an opposite response: a 42% (p = 0.01) decrease in mRNA levels for pro-alpha 2 (I) collagen was observed. Immunofluorescent staining of cardiac fibroblasts in culture with anti-type I collagen antibody showed that alterations in mRNA levels led to altered collagen synthesis: cellular collagen was relatively increased in TGF-beta 1-treated cells and significantly diminished in PMA-treated cells. The abundance of mRNA for pro-alpha 1 (III) collagen was not affected by PMA treatment.(ABSTRACT TRUNCATED AT 250 WORDS)
Eghbali
M
M
Cardiovascular Institute, Michael Reese Hospital, Chicago, IL.
Tomek
R
R
Sukhatme
V P
VP
Woods
C
C
Bhambi
B
B
D000818:Animals; D001345:Autoradiography; D002478:Cells, Cultured; D003094:Collagen / Q000096:biosynthesis / Q000235:genetics*; D005347:Fibroblasts / Q000187:drug effects; D005355:Fibrosis / Q000209:etiology; D005455:Fluorescent Antibody Technique; D015870:Gene Expression; D005809:Genes, Regulator; D006321:Heart / Q000187:drug effects*; D008297:Male; D009206:Myocardium / Q000166:cytology* / Q000378:metabolism; D011519:Proto-Oncogenes; D012333:RNA, Messenger / Q000235:genetics*; D011817:Rabbits; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*; D014157:Transcription Factors; D016212:Transforming Growth Factor beta / Q000494:pharmacology*
D012333:RNA, Messenger; D014157:Transcription Factors; D016212:Transforming Growth Factor beta; D003094:Collagen; D013755:Tetradecanoylphorbol Acetate