There are some reports demonstrating that introduction of fMLP into the gut induces colitis17,18. However, the dose used in these models was extremely high compared to physiological concentrations. Other studies have shown that not only fMLP but also various ligands of FPR1, such as AnxA1, and commensal bacteria, elicit epithelial barrier-protective effects19–22. IECs express Hsp27 via FPR1 stimulation, which has an epithelial-protective effect21. fMLP decreases TNF-α-induced NF-κB signaling and proinflammatory cytokine production and induces IEC migration. Moreover, fMLP can promote gastric epithelial cell proliferation by interacting with FPR122. FPR1 colocalizes with F-actin and activates Rac1 and Cdc42, which are crucial players in F-actin reorganization in a PI3K-dependent manner10.