The Notch signaling pathway controls basophil responses during helminth-induced type 2 inflammation

Abstract

Abstract Type 2 inflammation is characterized by production of the cytokines IL-4, IL-5 and IL-13 and is required for clearance of gastrointestinal helminth parasites, which infect over 2 billion people worldwide. Basophils are innate immune cells that promote expulsion of the helminth Trichuris muris in mice. However, the molecular mechanisms that control basophil function and gene expression during helminth-induced Type 2 inflammation remain unclear. We show that during T. muris infection, basophils localized to the intestine and upregulated components of the Notch signaling pathway, which regulates inflammatory gene expression programs. In vitro, Notch inhibition abrogated IL-33-elicited IL-4 and IL-6 production from basophils by directly targeting Il4 and Il6. Transcriptional profiling of Notch-deficient basophils revealed that Notch directs basophil responsiveness to inflammatory cues and effector gene expression. Mice lacking basophil-intrinsic Notch signaling had impaired worm clearance and decreased intestinal Type 2 effector mechanisms following infection. These findings demonstrate that Notch regulates basophil gene expression and effector function during helminth-induced Type 2 inflammation. We are now actively investigating how basophils interact with other cells in the intestine to orchestrate optimal Type 2 immune activation, and the role Notch plays in this process. These findings increase our understanding of the molecular signals that control innate immunity during Type 2 inflammation and may have far-reaching impact on the development of therapeutics aimed at modulating Type 2 immune responses.