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Atrial natriuretic peptide accelerates proliferation of chick embryonic cardiomyocytes in vitro
M Koide1, R E Akins, H Harayama
1National Chubu Hospital, Aichi, Japan.
Insights
Atrial natriuretic peptide (ANP) significantly boosts embryonic heart cell proliferation and DNA synthesis. This peptide accelerates cardiomyocyte development through a receptor-mediated pathway, suggesting an autocrine role in cardiac formation.
Area of Science:
- Cardiovascular Biology
- Developmental Biology
- Cell Biology
Background:
- Embryonic heart development involves complex cellular processes.
- Atrial natriuretic peptide (ANP) is present in developing embryonic hearts.
Purpose of the Study:
- To investigate the role of ANP in embryonic cardiac development.
- To analyze ANP's effects on cardiomyocyte proliferation and protein synthesis.
Main Methods:
- Cultured cardiomyocytes from chick embryos were treated with ANP.
- Assessed cell number, DNA synthesis (BrdU incorporation), RNA levels, and protein expression.
- Utilized ANP antibody and receptor antagonist (HS-142-1) to block ANP action.
Main Results:
- ANP significantly increased DNA synthesis and cell proliferation (P < 0.01).
- Enhanced cardiomyocyte network development, elevated RNA content, and increased myosin/tropomyosin biosynthesis.
- ANP promoted entry into S phase, indicated by increased G1/S-specific protein expression.
Conclusions:
- ANP accelerates myocardial cell proliferation via receptor-mediated pathways, enhancing DNA synthesis.
- ANP's in vitro effects and in vivo presence suggest an autocrine function in embryonic heart development.
Abstract:
The developing embryonic heart has been reported to contain significant levels of atrial natriuretic peptide (ANP). In this study, the role of ANP in cardiac development was evaluated using cultured cardiomyocytes isolated from chick embryos. We analyzed the effect of ANP on cell number, DNA synthesis, total RNA level, the expression of cell-cycle-specific and sarcomeric proteins, and levels of lactate dehydrogenase and creatine phosphokinase. ANP increased overall DNA synthesis (measured by BrdU incorporation, P < 0.01) and enhanced cell proliferation. Morphologically, the development of the cardiomyocyte network was distinctly enhanced in the ANP-treated cells. Cellular RNA content was elevated; likewise, myosin and tropomyosin biosynthesis was significantly greater in ANP-treated cells. In addition, expression of G1/S-specific protein increased, whereas G2/M-specific protein remained unchanged by ANP treatment. An antibody against ANP and a specific ANP receptor antagonist, HS-142-1, antagonized and/or attenuated the action of ANP on both cell proliferation and protein biosynthesis. These results indicate that ANP accelerates myocardial cell proliferation by enhancing entry into S phase and by increasing DNA synthesis during S phase specifically through receptor mediated pathway. The in vitro effects of ANP on myocardial cell proliferation, together with the elevated levels of ANP seen in vivo during normal heart formation, suggest a possible autocrine function of ANP in embryonic cardiac development.