Ouabain exerts protective effects on SH-SY5Y cells upon Zika virus infection

Zika virus (ZIKV) remains a significant global health threat due to its association with severe neurological disorders, yet no specific treatments are available. Ouabain (OUA) has demonstrated antiviral and immunomodulatory properties, but its mechanisms against ZIKV in neural cells are not fully understood. Here, we investigated the effects of OUA on ZIKV-infected SH-SY5Y cells, a model for undifferentiated neurons, and employed in silico analyses to elucidate its protective mechanisms. OUA exhibited potent antiviral activity, reducing ZIKV titers by up to 99.9% without cytotoxicity (selectivity index > 25). Additionally, OUA decreased the ZIKV-induced production of the pro-inflammatory cytokines IL-6 and TNF-α. Mechanistically, OUA suppressed ZIKV-induced NF-κB phosphorylation, providing a basis for its anti-inflammatory effects. Furthermore, OUA treatment restored the phosphorylation mTOR, ERK, and p38, important key neurogenesis-related proteins compromised by ZIKV infection. Moreover, both ZIKV and OUA additively increased SRC phosphorylation, a pathway previously linked to OUA's antiviral activity. In silico analyses predicted that OUA modulates numerous genes and proteins involved in cellular responses to viral infections. Collectively, our findings suggest a new mode of action for OUA in an undifferentiated neuronal cell model.