DPP4 and infection: To determine the effects of ACE2 depletion in HUVECs or DPP4 depletion in astrocytes and pericytes on infection with SARS-CoV-2, we first transduced the shLentiviruses on their respective cells for 48 h at the 1 IU/cell and then infected cells with 1 MOI SARS-CoV-2.