The COVID-19 pandemic has precipitated a surge in neurocognitive dysfunction, with long-term implications for global health systems and socioeconomic stability. Despite growing clinical recognition of post-COVID cognitive deficits ("brain fog"), the molecular mechanisms driving these impairments remain poorly understood. Our study addresses this critical gap by identifying SARS-CoV-2 nucleocapsid protein (SARS-CoV-2 N protein), a core structural component of the virus, as a novel etiological factor in senescence-mediated cognitive decline. We observed that SARS-CoV-2 N protein caused microglial senescence both in vivo and in vitro. Mechanistically, SARS-CoV-2 N protein-induced metabolic shifting toward glycolysis initiated a cascade of microglial senescence, which propagated cognitive impairment. We found that glycolysis inhibition reduced SARS-CoV-2 N protein-triggered microglial senescence and attenuated cognitive impairment in mice. Disrupted mitochondrial dynamics impaired oxidative phosphorylation capacity, forcing glycolytic reprogramming that ultimately triggered cellular senescence activation. We found that the SARS-CoV-2 N protein promoted excessive mitochondrial dysfunction in microglia, resulting in mitochondrial fragmentation. Inhibition of mitochondrial fission effectively rescued SARS-CoV-2 N protein-induced microglial senescence. In conclusion, our study suggests that the SARS-CoV-2 N protein induces senescence-mediated cognitive impairment by promoting glycolysis in microglia. Therapeutic targeting of glycolysis in SARS-CoV-2 N protein-triggered microglial senescence could be beneficial for treating or preventing cognitive impairment.
