RNA-seq analysis of WT and Pim1-/- BMDMs

The Pim (proviral integration site for Moloney murine leukemia virus) proteins form a serine threonine kinase family that regulates cell proliferation, migration and cell survival. Here we demonstrate for the first time that a Pim1 kinase plays an essential role in antiviral innate immune responses. Specifically, our in vivo, in vitro and RNA-sequencing analyses showed that Pim1 was quickly upregulated after Toll-like receptor (TLR) stimulation in a NF-kB-dependent manner and then promoted IFN-b production by forming a cell-surface complex composed of TRIF-signaling molecules and IRF3 that promoted IRF3 phosphorylation, nuclear translocation, and IFN-b production. As shown by Pim1 knockdown and knockout, Pim1 was essential for this role but its kinase activity was not involved. Pim1-deficiency increased the susceptibility of mice to poly I:C-induced sepsis. Our study uncovers a previously unrecognized role for Pim1 in antiviral innate immune responses, thus providing a new target for controlling viral infection. Overall design: Untreated WT BMDMs (n=3), LPS-treated WT BMDMs (n=3), untreated Pim1-/- BMDMs (n=3) and LPS-treated Pim1-/- BMDMs (n=3) were subjected to RNA-seq analysis