NOS3 and endothelial dysfunction: WT C57Bl/6 and eNOS+/− mice (since there is no complete deficiency of eNOS reported in humans, eNOS+/− mice were used over eNOS−/−) were infected with SARS-CoV-2 (MA10) to determine whether eNOS deficiency worsens acute COVID-19 morbidity, neuroinflammation, and senescence and promotes endothelial dysfunction.