Chrysotile asbestos stimulates platelet-derived growth factor-AA production by rat lung fibroblasts in vitro: evidence for an autocrine loop
| Autor: | Pamela M. Lindroos, P G Coin, James C. Bonner, J A Lasky, Arnold R. Brody, L E Ostrowski |
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| Rok vydání: | 1995 |
| Předmět: |
Pulmonary and Respiratory Medicine
Platelet-derived growth factor Asbestos Serpentine medicine.medical_treatment Clinical Biochemistry In Vitro Techniques chemistry.chemical_compound Phagocytosis Western blot Chrysotile medicine Animals Humans RNA Messenger Autocrine signalling Lung Molecular Biology Platelet-Derived Growth Factor biology medicine.diagnostic_test Growth factor Cell Biology Fibroblasts Molecular biology In vitro Rats Blot chemistry Microscopy Electron Scanning biology.protein Cattle Cell Division Platelet-derived growth factor receptor |
| Zdroj: | American Journal of Respiratory Cell and Molecular Biology. 12:162-170 |
| ISSN: | 1535-4989 1044-1549 |
| DOI: | 10.1165/ajrcmb.12.2.7865215 |
| Popis: | We have investigated the mitogenic and chemotactic role of platelet-derived growth factor (PDGF) in pulmonary fibrogenesis induced by chrysotile asbestos. Since fibroblasts phagocytize asbestos in the lung interstitium, we have sought to learn whether the fibers alter the production of PDGF-like molecules by rat lung fibroblasts or induce mitogenesis of these fibroblasts in vitro. Conditioned medium as well as cell lysates from fibroblasts exposed to asbestos contained approximately 4-fold more PDGF than unexposed cells as detected by Western blot. Two distinct molecular weight forms of PDGF (36 and 18 kD) were detected by Western blotting. We postulate that these PDGF-like molecules are homologues of human PDGF-AA since we could not detect any PDGF in a sensitive enzyme immunoassay that recognized only PDGF-BB and PDGF-AB. Furthermore, PDGF-A chain mRNA was readily detected by Northern analysis, whereas PDGF-B chain mRNA was not detected by conventional Northern analysis. However, message amplification using a reverse transcriptase polymerase chain reaction allowed detection of the B-chain message. A significant dose-dependent mitogenic effect of asbestos was found by using both a cell proliferation assay and nuclear labeling with bromodeoxyuridine when fibroblasts were exposed under serum-free conditions. This mitogenesis induced directly by asbestos was blocked almost entirely with an anti-PDGF antibody that neutralized all three PDGF isoforms. Thus, these data support our hypothesis that an autocrine loop for PDGF-AA is operative in vitro following exposure to asbestos in lung fibroblasts, and we suggest that this signaling pathway could be significant in the pathogenesis of pulmonary fibrosis. |
| Databáze: | OpenAIRE |
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