Role of P2X7 receptor in Clostridium perfringens beta-toxin-mediated cellular injury.

Background Clostridium perfringens beta-toxin is a pore-forming toxin (PFT) and an important agent of necrotic enteritis and enterotoxemia. We recently reported that beta-toxin strongly induced cell death in THP-1 cells via the formation of oligomers. We here describe that the P2X 7 receptor, which is an ATP receptor, interacts with beta-toxin. Methods We tested the role of P2X 7 receptor in beta-toxin-induced toxicity using specific inhibitors, knockdown of receptor, expression of the receptor and interaction by dot-blot assay. The potency of P2X 7 receptor was further determined using an in vivo mouse model. Results Selective P2X 7 receptor antagonists (oxidized ATP (o-ATP), oxidized ADP, and Brilliant Blue G (BBG)) inhibited beta-toxin-induced cytotoxicity in THP-1 cells. o-ATP also blocked the binding of beta-toxin to cells. The P2X 7 receptor and beta-toxin oligomer were localized in the lipid rafts of THP-1 cells. siRNA for the P2X 7 receptor inhibited toxin-induced cytotoxicity and binding of the toxin. In contrast, the siRNA knockdown of P2Y 2 or P2Y 6 had no effect on beta-toxin-induced cytotoxicity. The addition of beta-toxin to P2X 7 -transfected HEK-293 cells resulted in binding of beta-toxin oligomer. Moreover, beta-toxin specifically bound to immobilized P2X 7 receptors in vitro and colocalized with the P2X 7 receptor on the THP-1 cell surface. Furthermore, beta-toxin-induced lethality in mice was blocked by the preadministration of BBG. Conclusions The results of this study indicate that the P2X 7 receptor plays a role in beta-toxin-mediated cellular injury. General significance P2X 7 receptor is a potential target for the treatment of C. perfringens type C infection. [ABSTRACT FROM AUTHOR]