Role of cholinergic neuroimmune signaling pathway disruption in the pathogenesis of Hirschsprung-associated enterocolitis

PROJECT SUMMARY Hirschsprung disease (HSCR) is a congenital disorder of gastrointestinal tract characterized by the absence of enteric nervous system (ENS) along variable lengths of distal intestine. Children with HSCR are at risk for a devastating bowel inflammatory disorder, called Hirschsprung- associated enterocolitis (HAEC), that represents the leading cause of long-term morbidity and mortality and is associated with significant healthcare costs. Gaps in therapy are due to our incomplete understanding of the molecular and cellular causes of this condition. While lack of the ENS and immune dysregulation have been implicated in the pathophysiology of the HAEC, little is known about the role of neuroimmune interactions, which are so important in multiple functional gastrointestinal diseases. Our broad objective is to characterize the neuroimmune mechanisms underlying HAEC and to leverage this knowledge to test cell-based strategies to restore immune homeostasis and improve epithelial barrier function and the gut immunity. Based on our preliminary data, we hypothesize that disruption of normal ENS-innate lymphoid cell (ILC)-tuft cell (TC) interactions leads to the development and progression of intestinal inflammation. By utilizing murine model of HSCR, cell and organoid co-culture technologies, optogenetics, and cell transplantation techniques, we propose to test our hypothesis that loss of ENS in the aganglionic bowel of HSCR leads to disfunction of ILC-TC circuit that is associated with alterations of epithelial architecture and immune cell infiltration and disrupted intestinal innate immunity. We will also test our hypothesis that enteric neuronal cell therapy and optogenetic approach can restore immune homeostasis in vivo. The proposed studies will enhance our understanding of the role of the ENS in the immune dysregulation and marked declines in ILC and TC populations observed in the HAEC, and the results will allow us to identify novel potential therapies that target the primary cause of HAEC pathophysiology.