Then, to mechanistically prove that TNFα was involved in the COVID-19 induced ferroptotic response, we measured by immunoblot GPX4, SLC7A11, FTH1, and SAT1 after having treated HUVECs with a siRNA for TNFR1 or scramble (the efficiency of TNFR1 silencing is shown in Supplementary Figure S1). The gene discussed is SLC7A11; the disease is COVID-19.