Contribution of IL-17C-mediated macrophage polarization to Type 17 inflammation in neutrophilic asthma
Yuhuan Wen, Qile Chen, Hao Wang, Shiyun Xie, Honglv Chen, Wenruo Yao, Le Zhang, Weimin Sun, Junjie Wen, Xiaojing Yang, Kian Fan Chung, Qingling Zhang, Ailin Tao, Jie Yan
Abstract
BACKGROUND: IL-17C has been described in a variety of inflammatory diseases driven by neutrophils. However, the role of IL-17C in neutrophilic asthma has not been completely characterized. METHODS: The level of IL-17C in asthmatic patients and mice was assessed. Il-17c-deficient mice or mice treated with exogenous rmIL-17C were performed for OVA/CFA-induced asthmatic mice model. Pulmonary inflammation was evaluated by histological analysis, flow cytometry and cytokine analysis. Il-17re-overexpressed Raw264.7 were used in vitro to investigate the role of IL-17C in macrophage polarization. RESULTS: Here, we show IL-17C were increased in serum or plasma from asthmatic patients and OVA/CFA-induced asthma mice. In the OVA/CFA-induced model, exogenous rmIL-17C aggravated neutrophil- and Type 17-dominated inflammation and promoted M1 macrophage differentiation, whereas deficiency of Il-17c reversed the pro-inflammatory phenotypes and inhibited the expansion of M1 macrophages. In vitro, IL-17C in synergy with IFN-γ induced STAT1 activation in Il-17re overexpressed Raw264.7 to upregulate M1-related genes expression, and promoted pro-inflammatory M1 polymerization, whereas IL-17C in contrast to the effect of IL-4 inhibited STAT6 activation, to reduce Raw264.7 differentiation to M2 macrophage and functional M2-related genes expression. CONCLUSIONS: IL-17C promotes allergic inflammation via M1 polarization of pulmonary macrophages in neutrophilic asthma. Modulation of the IL-17C/IL-17RE axis represents a novel therapeutic target in neutrophilic asthma.