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Ascorbate-generated endogenous extracellular matrix affects cell protein synthesis in calf aortic smooth muscle cells
Experimental Cell Research
|October 1, 1985
Summary
Ascorbate supplementation increases extracellular matrix production and protein synthesis in smooth muscle cells by altering RNA levels. This suggests the collagen-rich matrix produced by ascorbate is key to these gene expression changes.
Area of Science:
- Cell Biology
- Biochemistry
- Molecular Biology
Background:
- Ascorbate (vitamin C) is known to stimulate extracellular matrix protein deposition and protein synthesis in cultured cells.
- The precise molecular mechanisms underlying ascorbate's effects on gene expression in smooth muscle cells require further investigation.
Purpose of the Study:
- To investigate the effect of ascorbate supplementation on gene expression in fetal calf aortic smooth muscle cells.
- To determine if ascorbate-induced changes in protein synthesis are mediated by alterations in RNA levels and extracellular matrix production.
Main Methods:
- Culturing fetal calf aortic smooth muscle cells with and without ascorbate.
- Measuring poly(A+) RNA content and in vitro protein synthesis via [35S]methionine incorporation.
- Analyzing gene expression using Northern hybridization with specific cDNA probes for beta-actin, alpha-tubulin, and type I pro alpha 1-collagen.
- Evaluating the impact of plating cells on collagen gels.
Main Results:
- Ascorbate supplementation increased poly(A+) RNA content and protein synthesis.
- Northern hybridization revealed increased sequence content for beta-actin, alpha-tubulin, and type I pro alpha 1-collagen in total RNA.
- No differences in mRNA sequence content were observed when equal amounts of poly(A+) RNA were compared.
- Cells grown on collagen gels without added ascorbate showed similar translational activity and mRNA content to ascorbate-treated cells on plastic.
- Early ascorbate treatment (one week) without significant matrix deposition did not yield similar results.
Conclusions:
- Ascorbate-induced protein synthesis stimulation in smooth muscle cells is linked to an increased proportion of poly(A+) RNA in the total RNA pool.
- The production of an endogenous, collagen-rich extracellular matrix in the presence of ascorbate appears to be the basis for these pretranslational changes.