Abstract
Cytokine release syndrome, also called cytokine storm, could cause lung tissue damage, acute respiratory distress syndrome (ARDS) and even death during SARS-CoV-2 infection. However, the underlying mechanisms of cytokine storm still remain unknown. Among these cytokines, the function of TNF-α and type I IFNs especially deserved further investigation. Here, we first found that TNF-α and IFN-β synergistically induced human airway epithelial cells BEAS-2B death. Mechanistically, the combination of TNF-α and IFN-β led to the activation of caspase-8 and caspase-3, which initiated BEAS-2B apoptosis. The activated caspase-8 and caspase-3 could further induce the cleavage and activation of gasdermin D (GSDMD) and gasdermin E (GSDME), which finally resulted in pro-inflammatory pyroptosis. The knock-down of caspase-8 and caspase-3 could effectively block the activation of GSDMD and GSDME, and then the death of BEAS-2B induced by TNF-α and IFN-β. In addition, pan-caspase inhibitor Z-VAD-FMK (ZVAD) and necrosulfonamide (NSA) could inhibit BEAS-2B death induced by TNF-α and IFN-β. Overall, our work revealed one possible mechanism that cytokine storm causes airway epithelial cells (AECs) damage and ARDS. These results indicated that blocking TNF-α and IFN-β-mediated AECs death may be a potential target to treat related viral infectious diseases, such as COVID-19.