TLR7 sensing of SARS-CoV-2 and IFN-I response by plasmacytoid dendritic cells leads to the hyperactivation of macrophages.

To gain a comprehensive understanding of type I IFN or SARS-CoV-2 activated pDCs priming macrophages in regulating TLR4 meidated gene expression, we treated primary human blood monocytes with 30ng/ml IFNα or the supernatant of SARS-CoV-2 activated pDCs for 24 h and followed by 2 ng/ml LPS for 3 h. Cells were harvested and performed transcriptomic analysis via RNA-seq. We found that IFNα and supernatant of SARS-CoV-2 activated pDCs had similar effects on priming macrophages to induce massive inflammatory gene expression mediated by LPS. mRNA of human primary monoyctes from 4 healthy donors treated with 30ng/ml IFNα or the supernatant of SARS-CoV-2 activated pDCs for 24 h and followed by 2 ng/ml LPS for 3 h were used for library preparing and RNA sequencing.