The P2 receptor antagonist PPADS abrogates LPS-induced neutrophil migration in the murine air pouch via inhibition of MIP-2 and KC production

In this work, we show that P2 nucleotide receptors control lipopolysaccharide (LPS)-induced neutrophil migration in the mouse air pouch model. Neutrophil infiltration in LPS-treated air pouches was reduced by the intravenous (iv) administration of the non-selective P2 receptor antagonist PPADS but not by suramin and RB-2. In addition, the iv administration of a P2 receptor ligand, UTP, enhanced LPS-induced neutrophil migration. In contrast, the iv injection of UDP had no effect on neutrophil migration. These data suggest that LPS-induced neutrophil migration in the air pouch could involve P2Y4 receptor which is antagonized by PPADS, activated by UTP, but not UDP, and insensitive to suramin. The inhibition of neutrophil migration by PPADS correlated with a diminished secretion of chemokines macrophage inflammatory protein-2 (MIP-2) and keratinocyte-derived chemokine (KC) in the air pouch exudates. As determined in vitro, PPADS did not affect MIP-2 and KC release from air pouch resident cells nor from accumulated neutrophils. MIP-2 and KC production in the LPS-treated air pouches correlated with an early neutrophil migration (1 h after LPS injection), and both of these effects were significantly reduced in mice administered with PPADS. Altogether, these data suggest that P2Y4 receptor expressed in circulating leukocytes and/or endothelium controls LPS-induced acute neutrophil recruitment in mouse air pouch.