Mitochondrial dysfunction enhances influenza pathogenesis by up-regulating de novo sialic acid biosynthesis.

Abstract

Mitochondrial dysfunction can trigger metabolic adaptations that resemble those induced by influenza A virus (IAV) infection. Here, we show that oxidative phosphorylation (OXPHOS) impairment, modeled by <i>Ndufs4</i> deficiency, reprograms lung epithelial metabolism to promote IAV pathogenesis. In both <i>Ndufs4</i> knockout (KO) mice and lung epithelial cells, OXPHOS deficiency increased glycolytic flux, diverting carbons into hexosamine and de novo sialic acid (SIA) biosynthesis pathways. This led to elevated sialylation and enhanced viral attachment. In <i>Ndufs4</i> KO models, adenosine monophosphate-activated protein kinase signaling was insufficient to blunt this increased metabolic flux. IAV infection further exacerbated this metabolic vulnerability, amplifying SIA and viral burden. Pharmacologic rerouting of glucose carbons with dichloroacetate reduced sialylation, viral replication, and inflammatory responses in <i>Ndufs4</i> KO models. These findings reveal that mitochondrial dysfunction enhances IAV susceptibility by disrupting energy sensing and fueling viral receptor biosynthesis, highlighting the importance of epithelial metabolism in viral pathogenesis and suggesting metabolic modulation as a potential therapeutic.