Abstract

Abstract Eosinophils are important in the pathogenesis of many diseases, including asthma, eosinophilic esophagitis and eczema. While IL-5 is necessary for the maturation of eosinophil progenitors (EoP) into mature eosinophils (EoM), the signals that promote commitment to the eosinophil lineage are unknown. The IL-33 receptor, ST2, is expressed on several inflammatory cells, including eosinophils, and is best characterized for its role during the initiation of allergic responses in the peripheral tissues. Recently, ST2 expression was described on hematopoietic stem cells, where its function remains unclear. Here, we sought to determine whether IL-33 and ST2 contribute to hematopoietic lineage decisions. We found that both IL-33- and ST2-deficient mice exhibited diminished peripheral blood eosinophils at baseline. Correspondingly, IL-33 administration increased EoM as well as IL-5 in the blood and bone marrow in WT and IL-33-deficient but not ST2-deficient mice. Blocking IL-5 with a neutralizing antibody prevented IL-33-expanded EoP from maturing into EoM, while transgenic overexpression of IL-5 in ST2-deficient mice resulted in significantly lower hypereosinophilia than transgenic IL-5 mice. Finally, we observed that IL-33, but not IL-5, specifically expanded EoP and upregulated IL-5Rα on EoP as well as increased IL-5 after bone marrow was cultured for three days. Our findings identify a basal defect in eosinophilopoiesis in IL-33- and ST2-deficient mice. Furthermore, we establish unappreciated roles for IL-33 and ST2 in eosinophil development via progenitor regulation and define a mechanism whereby IL-33 licenses commitment into the eosinophil lineage by driving both responsiveness to IL-5 and IL-5 production.

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.