Orai2 deficiency attenutates experimental colitis by facilitating the colonization of Akkermansia muciniphila.

Orai2 is a component of store-operated Calcium channels (SOCCs) and exerts a pivotal role in immunity. In intestinal macrophages (Mφs), Orai2 deficiency influenced linoleic acid (LA)-arachidonic acid (ARA) derivatives by regulating Pla2g6 and Alox5. 16S rRNA sequencing showed that deleting Orai2 facilitated the prevalence of Akkermansia muciniphila, and untargeted metabolomics confirmed the suppressed level of leukotriene A. Moreover, Orai2 deficiency ameliorated the progression of experimental murine colitis, as shown by attenuated structural collapse of colon and pro-inflammatory cytokine concentrations, and rescued dysbiosis. The administration of a Pla2g6 inhibitor (Bromoenol lactone) not only inhibited the relative abundance of A. muciniphila in the feces of Orai2 knockout (Orai2) mice, but also abolished the increased activity of Calcium-released activated Calcium channel (CRAC) in Orai2 intestinal Mφs, corroborating the involvement of Pla2g6 in Orai2 signaling. In conclusion, Orai2 deficiency increases Pla2g6 and hence facilitating A. muciniphila colonization, which might be a potential strategy to combat colitis.