N-Acetylcysteine Inhibits Coxsackievirus B3 Replication by Downregulating Eukaryotic Translation Elongation Factor 1 alpha 1

Group B Coxsackieviruses (CVB) are one of the causative pathogens of myocarditis, which may progress to cardiomyopathy. The pathogenesis of CVB is not fully understood, and effective antiviral therapy is not available. N-acetylcysteine (NAC), the classic antioxidant, has been used in clinical practice for several decades to treat various medical conditions. In this study, the anti-CVB effect of NAC was investigated. We show that NAC dramatically suppressed viral replication and alleviated cardiac injury induced by CVB3. To further study the antiviral mechanism of NAC, RNA-sequencing was performed for CVB3-infected cells with NAC treatment. We found that the eukaryotic elongation factor 1 alpha 1 (EEF1A1), but not EEF1A2, the highly homologous isoform of EEF1A1, is one of the most upregulated genes in CVB3-infected cells, while EEF1A1 expression was significantly suppressed by NAC treatment. eEF1A1 knockdown significantly inhibited CVB3 replication, implicating that eEF1A1 facilitates viral replication. Importantly, we show that eEF1A1, which was not expressed at the myocardium of newborn mice, was significantly upregulated by CVB3 infection. NAC markedly down-regulated the expression of eEF1A1 but not eEF1A2 in the myocardium of CVB3-infected mice. Furthermore, NAC accelerated eEF1A1 degradation by promoting autophagy in CVB3-infected cells. We show that p62, one of the critical adaptors of autophagic targets, interacts with eEF1A1 and was down-regulated in CVB3-infected cells upon NAC treatment. Taken together, this study demonstrated that NAC shows a potent anti-CVB effect through down-regulating eEF1A1.