Pharmacologic properties of P-2Z/P2X(7) receptor characterized in murine dendritic cells: role on the induction of apoptosis

In the immune system, extracellular adenosine 5'-triphosphate (ATP) mediate s a variety of effects mainly through activation of a particular receptor s ubtype, the pore-forming P-2Z/P2X(7) purinoceptor, This purinergic receptor has been described chiefly in cells of hemopoietic origin such as T cells, thymocytes, monocytes, macrophages, and phagocytic cells of thymic reticul um, In this study, we characterized the P-2Z/P2X(7) purinoceptor and the AT P-mediated apoptosis in murine spleen-derived dendritic cells (DCs), Dye up take and apoptosis were evaluated by flow cytometry, ATP-treated DCs were p ermeable to different low-molecular-weight fluorescent probes such as ethid ium bromide, YO-PRO 1, and lucifer yellow, Such an effect was dose-dependen t (EC50: 721 mu mol/L); mediated by the fully anionic agonist (ATP(4-)); an d specifically stimulated by ATP, BzATP, and ATP gamma S, Additionally, an ATP-induced increase in intracellular calcium was detected by microfluorome try, Furthermore, ATP treatment induced a significant increase in apoptotic DCs (64.46% +/- 3.8%) when compared with untreated control cells (34% +/- 5.8%), as ascertained by the TdT-mediated dUTP nick end labeling technique, Both ATP-induced DC permeabilization and apoptosis were inhibited by oxidi zed ATP, a P-2Z/P2X(7)-specific antagonist, In conclusion, we characterized the expression of the P-2Z/P2X(7) purinoceptor in murine spleen-derived DC s and described its role on the induction of apoptosis. (C) 2000 by The Ame rican Society of Hematology.