IL-10 production by ILC2s requires Blimp-1 and cMaf, modulates cellular metabolism, and ameliorates airway hyperreactivity.

Background: Group 2 innate lymphoid cells (ILC2s) are the dominant innate lymphoid cell population in the lungs at steady state, and their release of type 2 cytokines is a central driver in responding eosinophil infiltration and increased airway hyperreactivity. Our laboratory has identified a unique subset of ILC2s in the lungs that actively produce IL-10 (ILC2s).

Objective: Our aim was to characterize the effector functions of ILC2s in the development and pathology of allergic asthma.

Methods: IL-4-stimulated ILC2s were isolated to evaluate cytokine secretion, transcription factor signaling, metabolic dependence, and effector functions in vitro. ILC2s were also adoptively transferred into Rag2γc mice, which were then challenged with IL-33 and assessed for airway hyperreactivity and lung inflammation.

Results: We have determined that the transcription factors cMaf and Blimp-1 regulate IL-10 expression in ILC2s. Strikingly, our results demonstrate that ILC2s can utilize both autocrine and paracrine signaling to suppress proinflammatory ILC2 effector functions in vitro. Further, this subset dampens airway hyperreactivity and significantly reduces lung inflammation in vivo. Interestingly, ILC2s demonstrated a metabolic dependency on the glycolytic pathway for IL-10 production, shifting from the fatty acid oxidation pathway conventionally utilized for proinflammatory effector functions.

Conclusion: These findings provide an important and previously unrecognized role of ILC2s in diseases associated with ILC2s such as allergic lung inflammation and asthma. They also provide new insights into the metabolism dependency of proinflammatory and anti-inflammatory ILC2 phenotypes.