title: Epigenetic regulation of cardiac muscle-specific genes in H9c2 cells by Interleukin-18 and histone deacetylase inhibitor m-carboxycinnamic acid bis-hydroxamide.
abstract: Interleukin-18 (IL-18) elicited a robust hypertrophy response in H9c2 cardiomyocytes as judged by their accelerated rates of protein synthesis and increased cell size. Evidently, IL-18 treatment also induced a cardiac hypertrophy-specific program of gene expression in H9c2 cardiomyocytes since they elicited enhanced expression of atrial naturetic factor (ANF), desmin, and skeletal alpha-actin genes accompanied by a canonical switch in the transcription of alpha- and beta-myosin heavy chain (MyHC) genes. Co-treatment of H9c2 cells with m-carboxycinnamic acid bis-hydroxamide (CBHA), an inhibitor of histone deacetylases, significantly blocked both morphological and molecular manifestations of IL-18-induced cardiac hypertrophy in vitro. IL-18 treatment led to activation of phosphoinositide-3-kinase and phosphorylated Akt/protein kinase B, while CBHA blunted this pathway via inducing the expression of its upstream regulator, PTEN (phosphatase and tensin homolog). The architecture of bulk chromatin of H9c2 cells exposed to IL-18 and/or CBHA was significantly altered as judged by the extent of covalent modifications of its constituent histones. The chromatin immuno-precipitation (ChIP) assays revealed that IL-18-induced specific epigenetic changes in the chromatin of ANF, desmin, skeletal alpha-actin, and MyHC genes that were largely neutralized by CBHA. We demonstrate for the first time that 'histone code' of the entire approximately 50 kb genomic DNA encoding the alpha- and beta-MyHC genes and the intergenic DNA that generates anti-beta-MyHC RNA was uniquely modulated by pro- and anti-hypertrophy signals of IL-18 and CBHA, respectively.
authors.affiliation: Department of Pharmacology, University of Tennessee Health Science Center, Memphis, TN 38163, USA. gmajumdar@utmem.edu
authors.forename: Gipsy
authors.initials: G
authors.lastname: Majumdar
authors.forename: I Maria
authors.initials: IM
authors.lastname: Johnson
authors.forename: Santosh
authors.initials: S
authors.lastname: Kale
authors.forename: Rajendra
authors.initials: R
authors.lastname: Raghow
mesh_terms: D000804:Angiotensin II / Q000494:pharmacology; D002316:Cardiotonic Agents / Q000494:pharmacology; D002460:Cell Line; D002934:Cinnamates / Q000494:pharmacology*; D044127:Epigenesis, Genetic / Q000187:drug effects* / Q000502:physiology; D005786:Gene Expression Regulation / Q000187:drug effects*; D006321:Heart / Q000187:drug effects; D042421:Histone Code / Q000187:drug effects / Q000235:genetics; D056572:Histone Deacetylase Inhibitors; D006801:Humans; D006984:Hypertrophy / Q000139:chemically induced / Q000235:genetics; D020382:Interleukin-18 / Q000494:pharmacology*; D009206:Myocardium / Q000378:metabolism*; D009928:Organ Specificity / Q000235:genetics; D051059:PTEN Phosphohydrolase / Q000235:genetics / Q000378:metabolism; D010656:Phenylephrine / Q000494:pharmacology; D019869:Phosphatidylinositol 3-Kinases / Q000235:genetics / Q000378:metabolism; D010766:Phosphorylation; D024723:Ventricular Myosins / Q000235:genetics
chemical_list: D002316:Cardiotonic Agents; D002934:Cinnamates; D056572:Histone Deacetylase Inhibitors; D020382:Interleukin-18; C111238:carboxycinnamic acid bishydroxamide; D000804:Angiotensin II; D010656:Phenylephrine; D019869:Phosphatidylinositol 3-Kinases; D051059:PTEN Phosphohydrolase; C494929:PTEN protein, human; D024723:Ventricular Myosins