Open AccessSmall molecule regulators of postnatal Nkx 2.5 cardiomyoblast proliferation and differentiation
Author(s) -
Chen WenPin,
Wu Sean M.
Publication year - 2012
Publication title -
journal of cellular and molecular medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.44
H-Index - 130
eISSN - 1582-4934
pISSN - 1582-1838
DOI - 10.1111/j.1582-4934.2011.01513.x
Subject(s) - microbiology and biotechnology , population , protein kinase a , cell growth , cellular differentiation , chemistry , green fluorescent protein , biology , kinase , biochemistry , medicine , environmental health , gene
•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 Nkx 2.5 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 Nkx 2.5‐ GFP + cells in vitro . We found that A 83‐01 ( A 83), an inhibitor of TGF ‐βRI, was able to induce an expansion of neonatal Nkx 2.5‐ eGFP + cells. In addition, the ability of A 83 to expand eGFP + cells in culture was dependent on signalling from the mitogen‐activated protein kinase kinase ( MEK ) as treatment with a MEK inhibitor, PD 0325901, abolished this effect. On the other hand, activation of neonatal Nkx 2.5‐ eGFP + cells with TGF ‐β1, but not activin A nor BMP 2, led to smooth muscle cell differentiation, an effect that can be reversed by treatment with A 83. 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.