Essential Roles of c-Rel in TLR-Induced IL-23 p19 Gene Expression in Dendritic Cells

Abstract

IL-23 plays crucial roles in both immunity against pathogens and autoimmunity against self. Although it is well recognized that IL-23 expression is restricted to the myeloid lineage and is tightly regulated at the transcriptional level, the nature of transcription factors required for IL-23 expression is poorly understood. We report, in this study, that murine dendritic cells deficient in c-Rel, a member of the NF-κB family, are severely compromised in their ability to transcribe the p19 gene, one of the two genes that encode the IL-23 protein. The p19 gene promoter contains three putative NF-κB binding sites, two of which can effectively bind c-Rel as determined by chromatin immunoprecipitation and EMSA. Unexpectedly, mutation of either of these two c-Rel binding sites completely abolished the p19 promoter activity induced by five TLRs (2, 3, 4, 6, and 9) and four members of the NF-κB family (c-Rel, p65, p100, and p105). Based on these observations, we conclude that c-Rel controls IL-23 p19 gene expression through two κB sites in the p19 promoter, and propose a c-Rel-dependent enhanceosome model for p19 gene activation.

Deubiquitination of NF-κB by Ubiquitin-Specific Protease-7 promotes transcription

“…6A), demonstrating that p65 is the critical target for USP7 activity following TNFR activation. Using IL-23p19 promoter reporter plasmids lacking either of two essential NF-κB binding sites (29), we found that expression of USP7 CS does not inhibit LPS-inducible NF-κB-independent transcription (Fig. 6B).…”

“…To determine the degree to which the regulation of TLR-and TNFα-induced gene expression by USP7 is dependent upon its action on p65, we analyzed the effect of the expression of USP7 CS on IL-23p19 promoter reporter activity in WT and p65 −/− MEFs. IL-23p19 promoter activity is largely regulated by NF-κB (29), however when p65 −/− cells are stimulated with TNFα, there remains a significantly lower, but readily detectable, inducible reporter activity compared with WT cells (Fig. 6A).…”

“…The pNF-κB-luc and pAP1-luc plasmids were obtained from Clontech and pRL-TK from Promega. The IL23p19 reporter plasmids were previously described (29) and are detailed in SI Materials and Methods.…”

Prostaglandin E2-EP4 signaling persistently amplifies CD40-mediated induction of IL-23 p19 expression through canonical and non-canonical NF-κB pathways

“…23 Our finding of phosphorylation and nuclear translocation of p65 supports its involvement, and our study does not exclude the involvement of c-Rel, which was shown to be essential in TLRinduced p19 expression in BMDCs. 24 Thus, the sustained Il23a induction in CD40-stimulated BMDCs is apparently supported by switching from a canonical to a non-canonical NF-kB pathway during stimulation. Intriguingly, PGE 2 enhanced both phases of the induction in CD40-stimulated cells through EP4, thus amplifying the production of Il23a mRNA up to ten-fold.…”

Peroxiredoxin 1 Contributes to Host Defenses against Mycobacterium tuberculosis

“…These results suggest that PRDX1 positively regulate c-Rel translation. As c-Rel also regulates the expression of Il12a and Il23a mRNAs (31,32), the levels of both in WT and Prdx1 2/2 BMDMs after LPS stimulation were assayed. The levels of both Il12a and Il23a mRNAs were significantly lower in Prdx1 2/2 than in WT BMDMs (Fig.…”