DESCRIPTION (provided by applicant): The gastrointestinal epithelium functions as a dynamic barrier that serves as an interface between luminal contents and underlying tissue compartments, and is thus vital in maintaining mucosal homeostasis. Mucosal wounds have been observed following enteric infection, inflammatory bowel disease and ischemic insults. Disruption of the critical epithelial barrier allows access of luminal contents to immunologically privileged compartments thereby contributing to disease pathogenesis. In response to injury, intestinal epithelial cells (IEC) migrate and proliferate to rapidly cover denuded surfaces and re-establish the epithelia barrier. After identifying N-formyl peptide receptors (FPR1 and FPR2) in the intestinal epithelium, our studies suggest that FPR1 ligands including endogenous lipid/proteins and exogenous microbiota control intestinal epithelial homeostasis and repair. Thus, the proposed studies will further explore mechanisms by which these FPR ligands control restitution of the mucosal barrier. The proposed studies will not only provide a better understanding of basic mechanisms by which FPRs regulate epithelial repair, but will also aid in the development of new therapeutic strategies aimed at promoting healing of the injured mucosa.