IL-18 Drives ILC3 Proliferation and Promotes IL-22 Production via NF-?B.

ABSTRACT: Group 3 innate lymphoid cells (ILC3s) are important regulators of the immune system, maintaining homeostasis in the presence of commensal bacteria, but activating immune defenses in response to microbial pathogens. ILC3s are a robust source of IL-22, a cytokine critical for stimulating the antimicrobial response. We sought to identify cytokines that can promote proliferation and induce or maintain IL-22 production by ILC3s and determine a molecular mechanism for this process. We identified IL-18 as a cytokine that cooperates with an ILC3 survival factor, IL-15, to induce proliferation of human ILC3s, as well as induce and maintain IL-22 production. To determine a mechanism of action, we examined the NF-?B pathway, which is activated by IL-18 signaling. We found that the NF-?B complex signaling component, p65, binds to the proximal region of the IL22 promoter and promotes transcriptional activity. Finally, we observed that CD11c+ dendritic cells expressing IL-18 are found in close proximity to ILC3s in human tonsils in situ. Therefore, we identify a new mechanism by which human ILC3s proliferate and produce IL-22, and identify NF-?B as a potential therapeutic target to be considered in pathologic states characterized by overproduction of IL-18 and/or IL-22.

SUBMITTER: Victor AR 

PROVIDER: S-EPMC5624342 | biostudies-literature | 2017 Oct

REPOSITORIES: biostudies-literature