Please cite this article in press as: L. Kapustian, et al., Akt1 expression and activity at different stages in experimental heart failure, Pathophysiology (2013), http://dx.doi.org/10.1016/j.pathophys.2013.11.005 ARTICLE IN PRESS PATPHY-789; No. of Pages 5 Pathophysiology xxx (2013) xxx–xxx Akt1 expression and activity at different stages in experimental heart failure L. Kapustian a,∗ , I. Kroupskaya a , O. Rozhko a , V. Bobyk a , D. Ryabenko b , L. Sidorik a a Institute of Molecular Biology and Genetics, NAS of Ukraine, 150, Zabolotnogo Str., Kyiv 03680, Ukraine b National Scientific Center “M. D. Strazhesko Institute of Cardiology, MAS of Ukraine”, 5, Narodnogo Opolchenya Str., Kyiv 03151, Ukraine Received 28 October 2013; received in revised form 16 November 2013; accepted 19 November 2013 Abstract Loss of function or/and death of cardiomyocytes is one of the major contributing factors in the development of heart failure. Cytosolic Hsp60 can directly interact and regulate activation of some kinases and sequestrate certain proapoptotic molecules to avoid the cardiomyocyte apoptosis. We assumed that Akt1 kinase, a downstream effector of PI3 kinase, can interact with Hsp60. Our aim was to clarify the interaction of Akt1 and Hsp60 and to investigate the Akt1 expression in normal and failing hearts in acute and chronic stress. The experimental mouse models of inducible myocarditis and DCM-like pathology were developed in our laboratory. Akt1 and phospho-Akt1 (pS473) expression were studied by Western blot analysis. Co-immunoprecipitation method was used to test complex formation of Akt1 and Hsp60. The interaction of Hsp60 and Akt1 was detected for the first time by co-immunoprecipitation method in normal myocardium and under pathology as well. There were no significant changes in the level of Akt1 expression in both myocardia. At the same time we observed significant decrease in Akt1 phosphorylation at the final stage of DCM-like pathology but not at experimental myocarditis. The final stage of heart failure in mouse model of DCM-like pathology was characterized by reduced level of phospho-Akt1/Akt1 (pS473; -26%; P < 0.05), whereas no differences were found in total Akt1 protein content. We suggest a possible involvement of cytoplasmic Hsp60 in regulation of Akt1 activity at heart failure progression. © 2013 Elsevier Ireland Ltd. All rights reserved. Keywords: Akt kinase; Hsp60; Heart failure; DCM; Myocarditis; Mice 1. Introduction Congestive heart failure (CHF) is a significant medico- social problem in the world. The prevalence of CHF is increasing worldwide, and the prognosis of such patients remains pessimistic [1]. Dilated cardiomyopathy (DCM) is common heart disease and leads to heart failure. Etiology of DCM is unknown; the contributory factors are thought to be prior viral infections, cardiac specific autoantibodies, toxic agents, genetic factors, sustained alcohol consumption and other kinds of chronic stress. Some investigators con- sider that in many cases DCM is consequence of myocarditis progression [2]. Death of cardiomyocytes or their impaired functioning is thought to be the major contributing factor in ∗ Corresponding author at: Laboratory of Molecular Mechanisms of Autoimmunity, Institute of Molecular Biology and Genetics, NAS of Ukraine, 150, Zabolotnogo Str., Kyiv 03680, Ukraine. Tel.: +380 44 526 55 89; fax: +380 44 526 07 59. E-mail address: lyuda-kap@mail.ru (L. Kapustian). the development of DCM. The understanding of the mecha- nisms implicated in cardiomyocyte cell death is needed for the development of successful treatment. Many signal transduction cascades which control cell cycle, homeostasis and apoptosis are dependent on the assis- tance by molecular chaperones, which can maintain their target proteins in active or inactive conformations. Molecu- lar chaperone Hsp60 is one of the highest scientific interests due to lately revealed its antiapoptotic function in the cyto- plasm of cardiomyocytes. Hsp60 is primarily a mitochondrial protein, but significant amount of it (25–30%) is extramito- chondrial [3]. Previously we have observed an increase in total Hsp60 level in human DCM hearts as well as in the hearts of mice affected with experimental DCM-like pathology [4]. We observed the increase in Hsp60 level in mitochondria and decrease in cytoplasm, which could be one of the rea- sons for apoptotic response in cardiomyocytes at heart failure associated with chronic stress. Cytosolic form of Hsp60 was demonstrated to sequestrate proapoptotic molecules Bax and 0928-4680/$ – see front matter © 2013 Elsevier Ireland Ltd. All rights reserved. http://dx.doi.org/10.1016/j.pathophys.2013.11.005