Overexpression of the atypical homeodomain protein Hop in transgenic mice induces severe cardiac hypertrophy, which is prevented by treatment with the histone deacetylase inhibitor trichostatin A.
Activation of multiple pathways is associated with cardiac hypertrophy and heart failure. Repression of antihypertrophic pathways has rarely been demonstrated to cause cardiac hypertrophy in vivo. Hop is an unusual homeodomain protein that is expressed by embryonic and postnatal cardiac myocytes. Unlike other homeodomain proteins, Hop does not bind DNA. Rather, it modulates cardiac growth and proliferation by inhibiting the transcriptional activity of serum response factor (SRF) in cardiomyocytes. Here we show that Hop can inhibit SRF-dependent transcriptional activation by recruiting histone deacetylase (HDAC) activity and can form a complex that includes HDAC2. Transgenic mice that overexpress Hop develop severe cardiac hypertrophy, cardiac fibrosis, and premature death. A mutant form of Hop, which does not recruit HDAC activity, does not induce hypertrophy. Treatment of Hop transgenic mice with trichostatin A, an HDAC inhibitor, prevents hypertrophy. In addition, trichostatin A also attenuates hypertrophy induced by infusion of isoproterenol. Thus, chromatin remodeling and repression of otherwise active transcriptional processes can result in hypertrophy and heart failure, and this process can be blocked with chemical HDAC inhibitors.
Kook et al. (Mon,) conducted a other in Cardiac hypertrophy. Trichostatin A (TSA) vs. Vehicle was evaluated on Cardiac hypertrophy (heart weight-to-body weight ratio). Overexpression of the atypical homeodomain protein Hop in transgenic mice induces severe cardiac hypertrophy, which is prevented by treatment with the histone deacetylase inhibitor trichostatin A.