Differential effect of transforming growth factor beta on proteoglycan synthesis in human embryonic lung fibroblasts.
The effect of transforming growth factor beta (TGF-beta) on the biosynthesis of individual proteoglycans (PGs) by human embryonic lung fibroblasts has been investigated using specific antibodies and cDNA probes. Human lung fibroblasts secrete the two small chondroitin/dermatan sulfate PGs, PG-I or biglycan (300 kDa) and, in a larger proportion, PG-II or decorin (130 kDa). Metabolic labeling experiments reveal that TGF-beta induces selectively the expression of PG-I, whereas the level of PG-II remains unaltered. The effect of TGF-beta on PG-I and PG-II has been studied by immunoprecipitation and Northern blot analysis. Either at the core protein or mRNA level, a specific 5-fold increase in PG-I can be observed. TGF-beta acts probably at the transcriptional level, as actinomycin D blocks completely the TGF-beta induced proteoglycan synthesis. A low saturation density and a slower growth rate is also observed for TGF-beta treated cells. The possible role of PG-I and PG-II as mediators of the growth inhibition caused by TGF-beta is discussed.
Romarís
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Departament de Bioquímica i Biologia Molecular, Facultat de Veterinària, Universitat Autònoma de Barcelona, Bellaterra, Spain.
Heredia
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Molist
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Bassols
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D000818:Animals; D058578:Biglycan; D015152:Blotting, Northern; D002417:Cattle; D002455:Cell Division; D002460:Cell Line; D015342:DNA Probes; D058575:Decorin; D016326:Extracellular Matrix Proteins; D005347:Fibroblasts; D006801:Humans; D007700:Kinetics; D008168:Lung / Q000166:cytology / Q000187:drug effects / Q000196:embryology / Q000378:metabolism*; D011233:Precipitin Tests; D011509:Proteoglycans / Q000096:biosynthesis*; D012333:RNA, Messenger / Q000378:metabolism; D014158:Transcription, Genetic / Q000187:drug effects; D016212:Transforming Growth Factor beta / Q000494:pharmacology*
C546884:BGN protein, human; D058578:Biglycan; C546878:DCN protein, human; D015342:DNA Probes; D058575:Decorin; D016326:Extracellular Matrix Proteins; D011509:Proteoglycans; D012333:RNA, Messenger; D016212:Transforming Growth Factor beta