5-HT disturbs interaction between gut epithelium and commensal bacteria

The gut is considered as one of immune privilege sites, which is developed by complex interplay between gut microbiome and the intestinal epithelial barrier. The mechanisms regulating gut tolerance to the commensal bacteria also play an important role in the protection of intestine against epithelial injury. Human studies in patients with inflammatory bowel disease (IBD) have implicated aberrant communication between host and gut flora such as inappropriate immune responses against their own flora. In addition to the excessive production of proinflammatory cytokines, serotonin (5-hydroxytryptamine, 5-HT), an enteric neurotransmitter and paracrine hormone, is also increased in the gut of IBD patients, suggesting its role in the pathogenesis of IBD. In the present study, we examined the role of 5-HT in aberrant communication between gut epithelial cells and commensal bacteria (E coli).