Wnt5 controls splenic myelopoiesis and neutrophil functional ambivalency during DSS-induced colitis

Neutrophils are important innate immune cells with plasticity, heterogenicity, and functional ambivalency. While bone marrow is often regarded as the primary source of neutrophil production, the roles of extramedullary production in regulating neutrophil plasticity and heterogenicity in autoimmune diseases remain poorly understood. Here, we report that the lack of wingless-type MMTV integration site family member 5 (WNT5) unleashes anti-inflammatory protection against colitis in mice, accompanied by reduced colonic CD8+ T cell activation and enhanced splenic extramedullary myelopoiesis. In addition, colitis upregulates WNT5 expression in splenic stromal cells. The ablation of WNT5 leads to increased splenic production of hematopoietic niche factors, as well as elevated numbers of splenic neutrophils with heightened CD8+ T cell suppressive capability, in part due to elevated CD101 expression and attenuated pro-inflammatory activities. Thus, our study reveals a mechanism by which neutrophil plasticity and heterogenicity are regulated in colitis through WNT5 and highlights the role of splenic neutrophil production in shaping inflammatory outcomes. [Display omitted] •Loss of WNT5 protects mice from colitis by promoting splenic granulopoiesis•WNT5 proteins constitute negative feedback control of splenic granulopoiesis during colitis•Splenic granulopoiesis produces hyper-immunosuppressive and hypo-pro-inflammatory neutrophils Luan et al. report that the absence of WNT5 proteins in mice increases, through splenic granulopoiesis, the production of CD101-high hyper-immunosuppressive and hypo-inflammatory neutrophils. These neutrophils protect the mice from DSS-induced colitis.