Related Experiment Videos
Modulation of bFGF in lung fibroblasts by TGF-beta and PDGF
K T Goldsmith1, R B Gammon, R I Garver
1Department of Medicine, University of Alabama School of Medicine, Birmingham 35294.
The American Journal of Physiology
|December 11, 1991
Summary
Growth factors from alveolar macrophages may influence lung fibrosis by affecting basic fibroblast growth factor (bFGF) expression in lung fibroblasts. This study shows specific growth factors can increase bFGF gene and protein levels, potentially driving fibrotic processes.
Area of Science:
- Pulmonary Medicine
- Cell Biology
- Fibrosis Research
Background:
- Alveolar macrophages produce growth factors implicated in lung fibrosis.
- These factors are hypothesized to stimulate fibroblast proliferation and extracellular matrix deposition.
- The precise mechanisms by which macrophages influence fibroblast behavior in fibrotic lungs require further elucidation.
Purpose of the Study:
- To investigate if macrophage-derived growth factors modulate basic fibroblast growth factor (bFGF) expression in lung fibroblasts.
- To determine the effects of specific growth factors on bFGF gene and protein production.
- To understand the role of bFGF in the context of lung fibrotic diseases.
Main Methods:
- Utilized normal adult human lung fibroblast cell lines.
- Assessed bFGF gene expression via transcript analysis (Northern blot implied).
- Quantified bFGF protein levels using Western blot analysis.
- Investigated the impact of fetal calf serum (FCS), platelet-derived growth factor (PDGF), and transforming growth factor-beta (TGF-beta) on bFGF expression.
- Employed nuclear runoff assays to evaluate bFGF transcriptional rates.
Main Results:
- Fibroblasts constitutively express bFGF gene at basal levels.
- Fetal calf serum (FCS) significantly increased bFGF expression (5- to 10-fold).
- Platelet-derived growth factor (PDGF) increased steady-state bFGF expression by 108%.
- Transforming growth factor-beta (TGF-beta) markedly increased steady-state bFGF expression by 602%.
- PDGF and TGF-beta increased the relative rates of bFGF gene transcription.
- Neither PDGF nor TGF-beta alone increased detectable bFGF protein levels.
- Simultaneous addition of PDGF and TGF-beta, or FCS, led to a marked increase in bFGF protein.
Conclusions:
- Specific growth factors, namely PDGF and TGF-beta, found in fibrotic lung environments can significantly enhance bFGF gene expression in lung fibroblasts.
- While these factors increase bFGF transcription, protein levels are only markedly elevated under conditions of combined stimulation or FCS exposure.
- These findings suggest a complex regulatory mechanism where macrophage-derived factors contribute to the fibrotic process by modulating bFGF expression in lung fibroblasts.