Regulation of Type I Collagen Production by Insulin and Transforming Growth Factor-β in Human Lung Fibroblasts
| Autor: | Meir Krupsky, Alan Fine, Ping-Ping Kuang, John L. Berk, Ronald H. Goldstein |
|---|---|
| Rok vydání: | 1996 |
| Předmět: |
medicine.medical_specialty
Transcription Genetic medicine.medical_treatment Cycloheximide Biology Biochemistry chemistry.chemical_compound Rheumatology Transforming Growth Factor beta Internal medicine medicine Protein biosynthesis Humans Insulin Orthopedics and Sports Medicine RNA Messenger Proline Lung Molecular Biology Polyacrylamide gel electrophoresis Protein Synthesis Inhibitors Messenger RNA Cell Biology Transforming growth factor beta Fibroblasts Molecular biology Endocrinology chemistry Dactinomycin biology.protein Collagen Procollagen Type I collagen |
| Zdroj: | Connective Tissue Research. 34:53-62 |
| ISSN: | 1607-8438 0300-8207 |
| DOI: | 10.3109/03008209609028893 |
| Popis: | The effects and interaction of transforming growth factor-beta (TGF-beta) and insulin on collagen production in human fetal lung fibroblasts was examined. Fibroblasts were labeled with [3H]proline and collagen production was analyzed by polyacrylamide gel electrophoresis. The addition of insulin (2 micrograms/ml) increased collagen production 5 fold and TGF-beta (5 ng/ml) increased collagen production 6-fold. The combination of TGF-beta and insulin further increased type I collagen production (12 fold). We found that TGF-beta increased pro-alpha 1 (I) collagen mRNA levels 2-3 fold, insulin increased mRNA levels by less than 2 fold, and the combination stimulated a 3-4 fold increase. In a nuclear run-on assay, we found a 1.7 fold increase in the rate of transcription for the pro-alpha 1 (I) collagen gene in insulin-treated cultures and a 2-fold increase in TGF-treated cultures. In fibroblasts transfected with a plasmid containing 2.4 kb of the 5' flanking sequences of the human pro-alpha 1 (I) collagen gene, TGF-beta stimulated a 2.8 fold increase in promoter activity. In contrast, the addition of insulin stimulated a small increase (less than 2 fold) in the pro-alpha 1 (I) collagen promoter activity when administered alone or in combination with TGF-beta. Insulin prolonged the half-life of pro-alpha 1 (I) collagen mRNA from 9.1 h to 14.3 h as assessed by treatment with actinomycin D. The insulin-induced increase in pro-alpha 1 (I) collagen mRNA was blocked by the presence of cycloheximide indicating a requirement for new protein synthesis. These results show that the combination of TGF-beta and insulin stimulate large increases in type I collagen formation by acting at different sites in the collagen biosynthetic pathway. |
| Databáze: | OpenAIRE |
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