Pharmacologic properties of P2Z/P2X7 receptor characterized in murine dendritic cells:: role on the induction of apoptosis

In the immune system, extracellular adenosine 5'-triphosphate (ATP) mediates a variety of effects mainly through activation of a particular receptor subtype, 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 reticulum, In this study, we characterized the P-2Z/P2X(7) purinoceptor and the ATP-mediated apoptosis in murine spleen-derived dendritic cells (DCs), Dye uptake and apoptosis were evaluated by flow cytometry, ATP-treated DCs were permeable to different low-molecular-weight fluorescent probes such as ethidium bromide, YO-PRO 1, and lucifer yellow, Such an effect was dose-dependent (EC50: 721 mu mol/L); mediated by the fully anionic agonist (ATP(4-)); and specifically stimulated by ATP, BzATP, and ATP gamma S, Additionally, an ATP-induced increase in intracellular calcium was detected by microfluorometry, 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 oxidized 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 DCs and described its role on the induction of apoptosis. (C) 2000 by The American Society of Hematology.