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Development of chick cardiomyocytes: modulation of intermediate filaments by basic fibroblast and platelet-derived
C Vélez1, A E Aránega, J A Marchal
1Department of Health Sciences, University of Almería, Spain.
Insights
Basic fibroblast growth factor promotes cardiomyocyte differentiation by increasing desmin expression in early embryonic heart development. Platelet-derived growth factor, however, appears to have a dedifferentiating effect on cardiac muscle cells.
Area of Science:
- Cardiovascular Biology
- Developmental Biology
- Cell Biology
Background:
- Peptide growth factors are increasingly recognized for their functional roles in cardiac muscle.
- Embryonic cardiac muscle development involves complex regulatory mechanisms.
Purpose of the Study:
- To investigate the regulatory effects of basic fibroblast growth factor (bFGF) and platelet-derived growth factor (PDGF) on intermediate filament expression (desmin and vimentin) in embryonic chick cardiomyocytes.
- To determine if these growth factors influence cardiomyocyte differentiation during development.
Main Methods:
- Cultures of chick cardiomyocytes were treated with bFGF and PDGF at various embryonic developmental stages.
- Techniques included sodium dodecyl sulfate-gel electrophoresis, immunoblotting, and fluorescence-activated cell sorting analysis.
- Subcellular localization and expression levels of desmin and vimentin were quantified.
Main Results:
- Both desmin and vimentin expression were dependent on embryonic stage and growth factor treatment.
- bFGF significantly increased desmin expression in cytoplasmic and cytoskeletal compartments at Hamburger and Hamilton stage 19, but not in more mature stages.
- bFGF treatment led to a decreased rate of vimentin expression increase in later stages, while PDGF consistently increased vimentin expression, particularly in early developmental stages.
Conclusions:
- bFGF appears to play a role in promoting cardiomyocyte differentiation during early embryonic development.
- PDGF exhibits a potential dedifferentiating effect on cardiac muscle cells, as indicated by increased vimentin expression.
- These findings highlight distinct roles for bFGF and PDGF in regulating cardiac muscle development and differentiation.
Abstract:
Recent studies suggest that peptide growth factors play a functional role in cardiac muscle. To test whether embryonic cardiac muscle is a target for regulation by basic fibroblast growth factor and platelet-derived growth factor, we analyzed the effects of these peptides on the expression of the intermediate filaments desmin and vimentin at the subcellular level during development. Sodium dodecyl sulfate-gel electrophoresis, immunoblotting and fluorescence-activated cell sorting analysis were used to study the effect of basic fibroblast growth factor and platelet-derived growth factor on cultures of chick cardiomyocytes during development. Cytoplasmic and cytoskeletal concentrations of desmin and vimentin were dependent on the stage of embryonic development and on the type of growth factor added to the culture. The most significant finding was the increase in desmin expression in the cytoplasmic and cytoskeletal compartments after treatment with basic fibroblast growth factor (10 ng/ml) of chick heart cells at Hamburger and Hamilton stage 19. In more mature stages, basic fibroblast growth factor did not modify the levels of desmin expression. However, this factor led to a progressive deceleration in the rate of increase in vimentin expression. Platelet-derived growth factor increased vimentin expression in all stages studied, the greatest increases appearing in early stages of heart development. Our findings support the hypothesis that basic fibroblast growth factor plays a role in cardiomyocyte differentiation during the early stages of development, whereas platelet-derived growth factor has a dedifferentiating effect.