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Modulation of human bronchial epithelial cell IIICS fibronectin mRNA in vitro
E Rosi1, J D Beckmann, P Pladsen
1Clinica Medica III, Policlinico di Careggi, Firenze, Italy.
The European Respiratory Journal
|March 1, 1996
Summary
Human bronchial epithelial cells (BECs) produce fibronectin (Fn) with specific IIICS variants. Transforming growth factor-beta (TGF-beta) increases IIICS mRNA, while cAMP-influencing agents decrease it, offering insights into airway repair mechanisms.
Area of Science:
- Molecular Biology
- Cell Biology
- Biochemistry
Background:
- Fibronectin (Fn) is a crucial extracellular matrix glycoprotein in wound repair, particularly for injured airway epithelium.
- Bronchial epithelial cells (BECs) synthesize Fn with distinct properties compared to serum Fn, suggesting differential gene expression.
- Alternative splicing of the Fn gene regulates Fn production, with EIIIA region expression known in BECs, but IIICS region variants uncharacterized.
Purpose of the Study:
- To characterize human BEC Fn by determining the expression of alternative splice variants in the IIICS region.
- To investigate the modulation of IIICS mRNA expression by transforming growth factor-beta (TGF-beta) and cyclic adenosine monophosphate (cAMP)-influencing agents.
Main Methods:
- Cultured human bronchial epithelial cells (BECs) from bronchoscopy.
- Extracted total RNA and performed polymerase chain reaction (PCR) using specific primers for IIICS mRNA variants.
- Northern blot analysis with labeled IIICS, total Fn, and tubulin cDNA probes to assess mRNA expression modulation by TGF-beta, isoproterenol, and dibutryl cAMP (db-cAMP).
Main Results:
- Human BECs in culture expressed all five known human IIICS fibronectin variants.
- TGF-beta significantly enhanced IIICS mRNA expression in a dose- and time-dependent manner.
- Isoproterenol and db-cAMP reduced IIICS mRNA levels and attenuated TGF-beta-induced expression; total Fn mRNA changes paralleled IIICS mRNA changes.
Conclusions:
- Human airway epithelial cell fibronectin synthesized in vitro contains mRNA for all five IIICS variants.
- IIICS mRNA expression is modulated by TGF-beta and agents influencing cAMP.
- Further research is needed to determine if IIICS variant alterations contribute to functional differences between airway epithelial cell Fn and plasma-derived Fn.