title: HDAC activity regulates entry of mesoderm cells into the cardiac muscle lineage.
abstract: Class II histone deacetylases (HDAC4, HDAC5, HDAC7 and HDAC9) have been shown to interact with myocyte enhancer factors 2 (MEF2s) and play an important role in the repression of cardiac hypertrophy. We examined the role of HDACs during the differentiation of P19 embryonic carcinoma stem cells into cardiomyocytes. Treatment of aggregated P19 cells with the HDAC inhibitor trichostatin A induced the entry of mesodermal cells into the cardiac muscle lineage, shown by the upregulation of transcripts Nkx2-5, MEF2C, GATA4 and cardiac alpha-actin. Furthermore, the overexpression of HDAC4 inhibited cardiomyogenesis, shown by the downregulation of cardiac muscle gene expression. Class II HDAC activity is inhibited through phosphorylation by Ca2+/calmodulin-dependent kinase (CaMK). Expression of an activated CaMKIV in P19 cells upregulated the expression of Nkx2-5, GATA4 and MEF2C, enhanced cardiac muscle development, and activated a MEF2-responsive promoter. Moreover, inhibition of CaMK signaling downregulated GATA4 expression. Finally, P19 cells constitutively expressing a dominant-negative form of MEF2C, capable of binding class II HDACs, underwent cardiomyogenesis more efficiently than control cells, implying the relief of an inhibitor. Our results suggest that HDAC activity regulates the specification of mesoderm cells into cardiomyoblasts by inhibiting the expression of GATA4 and Nkx2-5 in a stem cell model system.
authors.affiliation: Department of Biochemistry, Medical Sciences Building, University of Western Ontario, London, Ontario, N6A 5C1, Canada.
authors.forename: Christina
authors.initials: C
authors.lastname: Karamboulas
authors.forename: Albert
authors.initials: A
authors.lastname: Swedani
authors.forename: Chris
authors.initials: C
authors.lastname: Ward
authors.forename: Ashraf S
authors.initials: AS
authors.lastname: Al-Madhoun
authors.forename: Sharon
authors.initials: S
authors.lastname: Wilton
authors.forename: Sophie
authors.initials: S
authors.lastname: Boisvenue
authors.forename: Alan G
authors.initials: AG
authors.lastname: Ridgeway
authors.forename: Ilona S
authors.initials: IS
authors.lastname: Skerjanc
mesh_terms: D000199:Actins / Q000235:genetics / Q000378:metabolism; D000818:Animals; D015152:Blotting, Northern; D054734:Calcium-Calmodulin-Dependent Protein Kinase Type 4; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000235:genetics / Q000378:metabolism; D002449:Cell Aggregation / Q000187:drug effects; D002454:Cell Differentiation / Q000187:drug effects; D045744:Cell Line, Tumor; D019070:Cell Lineage; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005455:Fluorescent Antibody Technique; D015870:Gene Expression / Q000187:drug effects; D006655:Histone Deacetylases / Q000235:genetics / Q000378:metabolism*; D064326:MEF2 Transcription Factors; D008648:Mesoderm / Q000166:cytology* / Q000378:metabolism; D008954:Models, Biological; D024510:Muscle Development / Q000187:drug effects; D009206:Myocardium / Q000166:cytology* / Q000378:metabolism; D018006:Myogenic Regulatory Factors / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D000199:Actins; D004791:Enzyme Inhibitors; D064326:MEF2 Transcription Factors; C578041:Mef2c protein, mouse; D018006:Myogenic Regulatory Factors; D054734:Calcium-Calmodulin-Dependent Protein Kinase Type 4; D017871:Calcium-Calmodulin-Dependent Protein Kinases; C517685:Camk4 protein, mouse; D006655:Histone Deacetylases