Project Summary Infections with Klebsiella pneumoniae (KP) activate the IL-17 signaling pathway, which is crucial to constrain KP dissemination and facilitate pathogen eradication. During this process, IL-17 is negatively regulated by RNA binding proteins (RBP) in an effort to decrease collateral tissue damage in the host. One of these RBPs is Regnase-1 (Reg1) which degrades IL-17- induced transcripts either through the coding region or 3'UTR. In this proposal, we will investigate the role of Reg1 in the airway epithelium during KP pneumonia. We hypothesize that Reg1 deficiency enhances the effect of pro-inflammatory transcripts in the airway epithelium which favors immunity against KP. For that purpose, we will characterize a Reg1 conditional knockout in the airway epithelium upon KP pneumonia as well as investigate Reg1 regulation at the epigenetic and post-transcriptional level.