title: Lysine methyltransferase Smyd2 suppresses p53-dependent cardiomyocyte apoptosis.
abstract: Apoptosis, or programmed cell death, is an essential physiological process for proper embryogenesis as well as for homeostasis during aging. In addition, apoptosis is one of the major mechanisms causing cell loss in pathophysiological conditions such as heart failure. Thus, inhibition of apoptosis is an important approach for preventive and therapeutic strategies. Here we show that the histone 3 lysine 4- and lysine 36-specific methyltransferase Smyd2 acts as an endogenous antagonistic player of p53-dependent cardiomyocyte apoptosis. Smyd2 protein levels were significantly decreased in cardiomyocytes upon cobalt chloride-induced apoptosis or myocardial infarction, while p53 expression was enhanced. siRNA-mediated knockdown of Smyd2 in cultured cardiomyocytes further enhanced cobalt chloride-induced cardiomyocyte apoptosis. In contrast, Smyd2 overexpression resulted in marked methylation of p53 and prevented its accumulation as well as apoptotic cell death in an Hsp90-independent manner. Moreover, overexpression, of Smyd2, but not Smyd2Y240F lacking a methyl transferase activity, significantly rescued CoCl2-induced apoptosis in H9c2 cardioblasts. Finally, Smyd2 cardiomyocyte-specific deletion in vivo promoted apoptotic cell death upon myocardial infarction, which correlated with enhanced expression of p53 and pro-apoptotic Bax. Collectively, our data indicate Smyd2 as a cardioprotective protein by methylating p53.
authors.affiliation: Department of Cardiac Development and Remodelling, Max-Planck-Institute for Heart and Lung Research, Parkstrasse 1, 61231 Bad Nauheim, Germany; Govt. College University Faisalabad, Allama Iqbal Road, Faisalabad 38000, Punjab, Pakistan.
authors.forename: Amna
authors.initials: A
authors.lastname: Sajjad
authors.affiliation: Department of Cardiac Development and Remodelling, Max-Planck-Institute for Heart and Lung Research, Parkstrasse 1, 61231 Bad Nauheim, Germany; Division Department of Pulmonary Pharmacotherapy, Justus-Liebig-University Giessen, Aulweg 130, 35392 Giessen, Germany. Electronic address: tatyana.novoyatleva@innnere.med.uni-giessen.de.
authors.forename: Tatyana
authors.initials: T
authors.lastname: Novoyatleva
authors.affiliation: Experimental Renal and Cardiovascular Research, Department of Nephropathology, Institute of Pathology, University of Erlangen-Nürnberg, Universitätsstraße 22, 91054 Erlangen, Germany.
authors.forename: Silvia
authors.initials: S
authors.lastname: Vergarajauregui
authors.affiliation: Kerckhoff Heart and Thorax Center, Department of Cardiology, 61231 Bad Nauheim, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Troidl
authors.affiliation: Division Department of Pulmonary Pharmacotherapy, Justus-Liebig-University Giessen, Aulweg 130, 35392 Giessen, Germany.
authors.forename: Ralph T
authors.initials: RT
authors.lastname: Schermuly
authors.affiliation: Institute for Cellular and Molecular Biology, University of Texas at Austin, 2506 Speedway Stop A5000, Austin, TX 78712-1191, USA.
authors.forename: Haley O
authors.initials: HO
authors.lastname: Tucker
authors.affiliation: Experimental Renal and Cardiovascular Research, Department of Nephropathology, Institute of Pathology, University of Erlangen-Nürnberg, Universitätsstraße 22, 91054 Erlangen, Germany. Electronic address: felix.engel@uk-erlangen.de.
authors.forename: Felix B
authors.initials: FB
authors.lastname: Engel
keywords: Apoptosis; Cardiomyocyte; Heart failure; Smyd2; p53