RSV‐Induced Regulation of DC via H3K4 Demethylase KDM5b

ABSTRACT We previously observed an upregulation of Kdm5b , an H3K4 demethylase, following RSV infection of DCs that regulates key innate cytokines, including Type I IFN and TNF. As H3K4 tri‐methylation is an activating mark, this demethylase acts as a transcriptional repressor to specific gene targets. Our in vitro and transcriptomic data show genomic ablation of Kdm5b in DC leads to greater antiviral responses following RSV and TLR stimulation. This includes upregulation of type I IFN and downstream elements such as Cxcl10 , Oasl1 , and Mx2 genes. While more than 500 genes appear to be regulated in the KDM5B‐KO DC after RSV infection compared with WT DC, specific transcriptional regulation linked to type I responses was indicated. Utilizing the transcription factor prediction tool BART revealed IRF3, IRF7, and STAT1 as regulatory factors for the differentially expressed genes following TLR re‐stimulation of RSV‐infected KDM5B‐KO DC. To further extend these findings to an in vivo setting, KDM5b‐CD11c‐CRE+ mice were re‐infected by RSV 3 weeks after a primary RSV infection when the virus was cleared and demonstrated reduced RSV‐induced pathology. This scenario of protection from pathology was further extended in allergic asthmatic KDM5b‐CD11c‐CRE+ mice during RSV‐induced exacerbation but not with allergens without RSV infection.