Concurrent opposite effects of trichostatin A, an inhibitor of histone deacetylases, on expression of {alpha}-MHC and cardiac tubulins: implication for gain in cardiac muscle contractility

• Published in: American journal of physiology. Heart and circulatory physiology 2005-03, Vol.288 (3), p.H1477
• Main Authors: Davis, Francesca J, Pillai, Jyothish B, Gupta, Madhu, Gupta, Mahesh P
• Format: Article
• Language: English
• ISSN: 0363-6135; 1522-1539
• DOI: 10.1152/ajpheart.00789.2004

1 Department of Surgery (Division of Cardiothoracic Surgery) and 3 Committee on Molecular Medicine, University of Chicago, Chicago; 2 The Heart Institute of Children, Hope Childrens Hospital, Oak Lawn, and Department of Physiology and Biophysics, University of Illinois, Chicago, Illinois Submitted 4 August 2004 ; accepted in final form 15 September 2004 Histone deacetylases (HDACs) are a family of enzymes that catalyze the removal of acetyl groups from core histones, resulting in change of chromatin structure and gene transcription activity. In the heart, HDACs are targets of hypertrophic signaling, and their nonspecific inhibition by trichostatin A (TSA) attenuates hypertrophy of cultured cardiac myocytes. In this study, we examined the effect of TSA on two major determinants of cardiac contractility: -myosin heavy chain (MHC) expression and microtubular composition and organization. TSA upregulated the expression of -MHC in cultured cardiac myocytes, as well as in an in vivo model of hypothyroid rats. Studies designed to delineate mechanisms of -MHC induction by TSA revealed an obligatory role of early growth response factor-1 on activation of the -MHC promoter. Concurrently, TSA downregulated the expression of - and -tubulins and prevented the induction of tubulins by a hypertrophy agonist, ANG II. The ANG II-mediated increased proportion of - and -tubulins associated with polymerized microtubules was also markedly reduced after treatment of cells by TSA. Results obtained from immunofluorescent microscopy indicated that TSA had no noticeable effect on the organization of cardiac microtubules in control cells, whereas it prevented the ANG II-induced dense parallel linear arrays of microtubules to a profile similar to that of controls. Together, these results demonstrate that inhibition of HDACs by TSA regulates the cardiac -MHC and tubulins in a manner predictive of improved cardiac contractile function. These studies improve our understanding of the role of HDACs on cardiac hypertrophy with implications in development of new therapeutic agents for treatment of cardiac abnormalities. histone deacetylase inhibitors; myosin heavy chain; hypertrophy; heart failure Address for reprint requests and other correspondence: M. P. Gupta, Dept. of Surgery, MC 5040, Univ. of Chicago, 5841 S. Maryland Ave, Chicago, IL 60637 (E-mail: mgupta{at}surgery.bsd.uchicago.edu )