N-Acetyl cysteine effectively alleviates Coxsackievirus B-Induced myocarditis through suppressing viral replication and inflammatory response

Viral myocarditis caused by Coxsackievirus B (CVB) infection is a severe inflammatory disease of the myocardium, which may develop to cardiomyopathy and heart failure. No effective specific treatment is available. Our previous study demonstrated that suppression of proinflammatory caspase-1 activation effectively inhibited CVB replication. N-acetyl cysteine (NAC) is a widely used antioxidant. In this study, we found that NAC significantly alleviated the myocardial injury caused by CVB type 3 (CVB3) under in vivo condition. Importantly, NAC treatment simultaneously suppressed viral replication and inflammatory response in both myocardium and cell culture. The antiviral and anti-inflammation mechanism of NAC, while independent of its antioxidant property, relies on its inhibition on caspase-1 activation. Moreover, NAC promotes procaspase-1 degradation via ubiquitin proteasome system, which further contributes to caspase-1 down-regulation. NAC also inhibits the activity of viral proteases. Taken together, this study shows that NAC exerts potent anti-CVB and anti-inflammation effect through targeting caspase-1. Given that NAC is a clinically approved medicine, we recommend NAC as a valuable therapeutic agent for viral myocarditis caused by CVB.