Vergani, AndreaFotino, CarmenD’Addio, FrancescaTezza, SaraPodetta, MicheleGatti, FrancescaChin, MelissaBassi, RobertoMolano, Ruth D.Corradi, DomenicoGatti, RitaFerrero, Maria E.Secchi, AntonioGrassi, FabioRicordi, CamilloSayegh, MohamedMaffi, PaolaPileggi, AntonelloFiorina, Paolo2014-07-072013Vergani, A., C. Fotino, F. D’Addio, S. Tezza, M. Podetta, F. Gatti, M. Chin, et al. 2013. “Effect of the Purinergic Inhibitor Oxidized ATP in a Model of Islet Allograft Rejection.” Diabetes 62 (5): 1665-1675. doi:10.2337/db12-0242. http://dx.doi.org/10.2337/db12-0242.0012-1797http://nrs.harvard.edu/urn-3:HUL.InstRepos:12407037The lymphocytic ionotropic purinergic P2X receptors (P2X1R-P2X7R, or P2XRs) sense ATP released during cell damage-activation, thus regulating T-cell activation. We aim to define the role of P2XRs during islet allograft rejection and to establish a novel anti-P2XRs strategy to achieve long-term islet allograft function. Our data demonstrate that P2X1R and P2X7R are induced in islet allograft-infiltrating cells, that only P2X7R is increasingly expressed during alloimmune response, and that P2X1R is augmented in both allogeneic and syngeneic transplantation. In vivo short-term P2X7R targeting (using periodate-oxidized ATP [oATP]) delays islet allograft rejection, reduces the frequency of Th1/Th17 cells, and induces hyporesponsiveness toward donor antigens. oATP-treated mice displayed preserved islet grafts with reduced Th1 transcripts. P2X7R targeting and rapamycin synergized in inducing long-term islet function in 80% of transplanted mice and resulted in reshaping of the recipient immune system. In vitro P2X7R targeting using oATP reduced T-cell activation and diminished Th1/Th17 cytokine production. Peripheral blood mononuclear cells obtained from long-term islet-transplanted patients showed an increased percentage of P2X7R+CD4+ T cells compared with controls. The beneficial effects of oATP treatment revealed a role for the purinergic system in islet allograft rejection, and the targeting of P2X7R is a novel strategy to induce long-term islet allograft function.en-USImmunology and TransplantationJournal Article2014-07-0710.2337/db12-0242