For instance, in response to microbial invasion, Drosophila activates the Imd pathway mediated by the expression of tachykinin-related peptide (Tk) in EECs of the foregut and midgut, and mammals activate the NF-κB pathway mediated by the expression of Toll-like receptors in EECs [37], which plays a significant role in the regulation of IBD. This evidence concerns the gene NFKB1 and inflammatory bowel disease.