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Mechanisms of stimulation of collagen synthesis during chick embryonic skin development
K Ohyama1, I Tokimitsu, S Tajima
1Department of Dermatology, Keio University School of Medicine, Tokyo.
Insights
Collagen synthesis regulation in chick embryonic skin is primarily controlled by collagen messenger RNA (mRNA) levels during later developmental stages (days 15-18). Cell-matrix interactions and serum factors are crucial for this stimulation.
Area of Science:
- Developmental Biology
- Molecular Biology
- Biochemistry
Background:
- Collagen synthesis is vital for embryonic skin development.
- Understanding the regulation of collagen synthesis is key to developmental processes.
Purpose of the Study:
- To investigate the regulation of collagen synthesis in developing chick embryonic skin.
- To compare collagen synthesis, hydroxyproline, and proline incorporation at different developmental stages (12, 15, and 18 days).
- To analyze the role of type I procollagen mRNA levels and translational activity in collagen synthesis regulation.
Main Methods:
- Quantification of hydroxyproline synthesis and proline incorporation.
- Measurement of translational activity and content of type I procollagen mRNA.
- Analysis of collagen synthesis in isolated fibroblasts under varying culture conditions.
Main Results:
- Hydroxyproline synthesis significantly increased from day 12 to day 18.
- Collagen synthesis increase from day 15 to 18 correlated with elevated type I procollagen mRNA activity and content.
- Collagen synthesis stimulation from day 12 to 15 did not directly correlate with type I procollagen mRNA levels.
- Isolated fibroblasts showed constant collagen synthesis and mRNA levels, independent of culture conditions.
Conclusions:
- Collagen synthesis regulation by collagen mRNA levels is stage-specific, becoming significant in later embryonic development (days 15-18).
- Cell-matrix interactions and serum factors are essential for the marked increase in collagen synthesis observed in developing chick skin.
- The findings highlight a complex regulatory mechanism involving mRNA levels and extracellular/serum factors in embryonic collagen production.
Abstract:
To study how collagen synthesis is regulated in developing chick embryonic skin, hydroxyproline synthesis, incorporation of proline, and translational activity and content of collagen mRNA in 12-, 15-, and 18-day skins were determined and compared with each other. Hydroxyproline synthesis in the 18-day skins was markedly increased over that in the 12-day skins, whereas proline incorporation was moderately increased. The increase in collagen synthesis from day 15 to 18 was accompanied by increases in both the translational activity and the content of type I procollagen mRNA, with a selective increase in the lower-molecular-weight species of pro alpha 1 (I) collagen mRNA. In contrast, the stimulation of collagen synthesis from day 12 to day 15 did not parallel the levels of type I procollagen mRNA. These results suggest that the stimulation of collagen synthesis is regulated by collagen mRNA levels only in the later stage of development (from day 15 to day 18). Both the collagen synthesis and type I procollagen mRNA levels in the fibroblasts isolated on each corresponding day were constant. The difference in collagen synthesis under two different culture conditions suggests that cell-matrix interaction and/or some serum factors, including several growth factors, are essential for the marked stimulation of collagen synthesis observed in 12- to 18-day skin.