Small molecule regulators of postnatal Nkx2.5 cardiomyoblast proliferation and differentiation

Journal of Cellular and Molecular Medicine

Wen-Pin Chen¹ 

[1] Institute of Pharmacology, College of Medicine, National Taiwan University, Taipei, Taiwan

关键词: Nkx2.5;    cardiomyoblast;    TGF‐β;   

DOI  :  10.1111/j.1582-4934.2011.01513.x

来源: Wiley

【 摘 要 】

Abstract

• •Introduction to postnatal cardiac progenitor cells
• •Methods to examine postnatal CPCs with small molecules
•  -Transgenic mice
•  -Cell culture
•  -Measurement of cell proliferation
•  -Flow cytometry
•  -Immunofluorescence
•  -Chemical reagents
• •Results and discussion of small molecule effects on CPCs
•  -Modulation of TGF-β but not activin A or BMP2 signalling affects smooth muscle cell differentiation of neonatal Nkx2.5⁺ cardiomyoblasts
•  -Small molecule inhibition of Alk receptors induces an expansion of neonatal Nkx2.5-eGFP⁺ cells

While recent data have supported the capacity for a neonatal heart to undergo cardiomyogenesis, it is unclear whether these new cardiomyocytes arise from an immature cardiomyoblast population or from the division of mature cardiomyocytes. By following the expression of enhanced Green Fluorescent Protein (eGFP) in an Nkx2.5 enhancer-eGFP transgenic mice, we have identified a population of immature cells that can undergo cardiomyogenic as well as smooth muscle cell differentiation in the neonatal heart. Here, we examined growth factors and small molecule regulators that potentially regulate the proliferation and cardiomyogenic versus smooth muscle cell differentiation of neonatal Nkx2.5-GFP⁺ cells in vitro. We found that A83-01 (A83), an inhibitor of TGF-βRI, was able to induce an expansion of neonatal Nkx2.5-eGFP⁺ cells. In addition, the ability of A83 to expand eGFP⁺ cells in culture was dependent on signalling from the mitogen-activated protein kinase kinase (MEK) as treatment with a MEK inhibitor, PD0325901, abolished this effect. On the other hand, activation of neonatal Nkx2.5-eGFP⁺ cells with TGF-β1, but not activin A nor BMP2, led to smooth muscle cell differentiation, an effect that can be reversed by treatment with A83. In summary, small molecule inhibition of TGF-β signalling may be a promising strategy to induce the expansion of a rare population of postnatal cardiomyoblasts.

【 授权许可】

Unknown   
© 2011 The Authors Journal of Cellular and Molecular Medicine © 2011 Foundation for Cellular and Molecular Medicine/Blackwell Publishing Ltd