HIF1A and severe acute respiratory syndrome: In hypoxic monocytes, HIF-1α negatively regulates the interferon expression.145 Upon severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, HIF-1α signaling pathway activates the interferon and pro-inflammatory cytokines.146 In a previous study, we revealed that SARS-CoV-2 infection induces HIF-1α expression, thereby promoting viral replication and virus-induced inflammatory responses.147 HIF-1α is widely expressed in different innate immune cells, including macrophages, dendritic cells (DCs), and neutrophils.