trichostatin-a and Myocarditis

Viral myocarditis, which is most prevalently caused by coxsackievirus B3 (CVB3), is a serious clinical condition characterized by excessive myocardial inflammation. Recent studies suggest that regulation of protein acetylation levels by inhibiting histone deacetylase (HDAC) activity modulates inflammatory response and shows promise as a therapy for several inflammatory diseases. However, the role of HDAC activity in viral myocarditis is still not fully understood. Here, we aim to investigate the role of HDAC activity in viral myocarditis and its underlying mechanism. CVB3-infected BALB/c mice were treated with the HDAC inhibitor (HDACI) suberoylanilide hydroxamic acid (SAHA) or trichostatin A (TSA). We found inhibition of HDAC activity aggravated rather than ameliorated the severity of CVB3-induced myocarditis, which was contrary to our expectations. The aggravated myocarditis by HDACI treatment seemed not to be caused by an elevated inflammatory response but by the increased CVB3 replication. Further, it was revealed that the increased CVB3 replication was closely associated with the HDACI-enhanced autophagosome formation. Inhibition of autophagosome formation by wortmannin or ATG5 short hairpin RNA dramatically suppressed the HDACI-increased CVB3 replication. The increased viral replication subsequently elevated CVB3-induced myocardial apoptosis. Conversely, inhibition of CVB3 replication and ensuing myocardial apoptosis by the antiviral drug ribavirin significantly reversed the HDACI-aggravated viral myocarditis. In conclusion, we elucidate that the inhibition of HDAC activity increases CVB3 replication and ensuing myocardial apoptosis, resulting in aggravated viral myocarditis. Possible adverse consequences of administering HDACI should be considered in patients infected (or coinfected) with CVB3.. Viral myocarditis, which is most prevalently caused by CVB3, is characterized by excessive myocardial inflammation. Inhibition of HDAC activity was originally identified as a powerful anti-cancer therapeutic strategy and was recently found to be implicated in the regulation of inflammatory response. HDACI has been demonstrated to be efficacious in animal models of several inflammatory diseases. Thus, we hypothesize that inhibition of HDAC activity also protects against CVB3-induced viral myocarditis. Surprisingly, we found inhibition of HDAC activity enhanced myocardial autophagosome formation, which led to the elevated CVB3 viral replication and ensuing increased myocardial apoptosis. Viral myocarditis was eventually aggravated rather than ameliorated by HDAC inhibition. In conclusion, we elucidate the role of HDAC activity in viral myocarditis. Moreover, given the importance of HDACI in preclinical and clinical treatments, the possible unfavorable effect of HDACI should be carefully evaluated in patients infected with viruses, including CVB3.

Topics: Androstadienes; Animals; Antiviral Agents; Apoptosis; Autophagy-Related Protein 5; Coxsackievirus Infections; Disease Models, Animal; Enterovirus B, Human; Gene Expression Regulation; Histone Deacetylase Inhibitors; Histone Deacetylases; Humans; Hydroxamic Acids; Male; Mice; Mice, Inbred BALB C; Microtubule-Associated Proteins; Myocarditis; Myocardium; Phagosomes; Ribavirin; RNA, Small Interfering; Virus Replication; Vorinostat; Wortmannin

Clinical importance of myocarditis, predominantly caused by coxsackievirus B3 (CVB3), is recently rising. However, a detailed mechanism of pathogenesis of CVB3 myocarditis still needs to be clarified. Recently, it has been reported that histone modifications including acetylation are involved in coxsackievirus replication. To examine whether the CVB3 replication requires histone acetylation, histone deacetylase (HDAC) inhibitors were employed. We found that the HDAC2 activity increased in virus-infected cells at 12 hrs p.i. and that HDAC inhibitors suppressed the virus replication in vitro. This suggests that the HDAC2 activity may be required for the virus replication. Eventually, a HDAC inhibitor trichostatin A protected against CVB3-induced myocardial injury in vivo. Our results suggest that HDAC may be a novel therapeutic target for treating viral myocarditis.. coxsackievirus B3; histone acetyltransferase; histone deacetylase; HDAC inhibitors, trichostatin A; apicidin; valproic acid; shRNA; myocarditis; mouse.

Topics: Animals; Coxsackievirus Infections; Enterovirus B, Human; Enterovirus Infections; HeLa Cells; Histone Deacetylase 2; Histone Deacetylase Inhibitors; Humans; Hydroxamic Acids; Male; Mice; Mice, Inbred BALB C; Myocarditis; Virus Replication