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

Abstract

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 P2Y 4 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 P2Y 4 receptor expressed in circulating leukocytes and/or endothelium controls LPS-induced acute neutrophil recruitment in mouse air pouch.

NTPDase1 Controls IL-8 Production by Human Neutrophils

“…In agreement with the latter role for neutrophils, we found that inhibition of early neutrophil migration in vivo by the P2 receptor antagonist, pyridoxalphosphate-6-azophenyl-29,49-disulfonic acid, decreased the release of the chemokines MIP-2 and KC (whose roles in mice are similar to those of IL-8 in humans), which reduced the migration of new neutrophils at the site of inflammation (41). A significant body of evidence further confirms our current observation that NTPDase1 expressed in neutrophils might play an important role in shaping immune responses.…”

“…Using the LPStreated air pouch as a model of acute inflammation with a predominant role of neutrophils, we observed that NTPDase1-KO mice produced more MIP-2 and KC than WT. Neutrophils represent .90% of all cells accumulated in the air pouch 4 h after LPS injection, and they contribute to MIP-2 and KC production in the air pouch (41). Therefore, this increased production of MIP-2 and KC in NTPDase1-KO mice could be due to neutrophil accumulation, which is maximal in the air pouch at this time point.…”

“…The injection of LPS in the air pouches causes robust neutrophil accumulation and chemokine production, and both parameters can be measured with precision in inflammatory exudates collected from the air pouches (41). Neutrophil recruitment in rodents is triggered by the chemokines MIP-2 and KC, which are the functional counterparts of human IL-8.…”

Extracellular ATP‐stimulated macrophages produce macrophage inflammatory protein‐2 which is important for neutrophil migration

“…Both KC and MIP‐2 play an important role in neutrophil migration, and these chemokines are mainly produced by macrophages 24–29 . The increase in number of neutrophils and macrophages in the peritoneal cavity of ATP‐injected mice raises the question of whether macrophages are involved in neutrophil migration.…”

“…In humans, CXC ligand (CXCL) 8/IL‐8 plays a major role in neutrophil migration 21–23 . In mice, CXCL1/keratinocyte‐derived chemokine (KC) and CXCL2/macrophage inflammatory protein‐2 (MIP‐2), both murine functional homologues of IL‐8, recruit neutrophils to sites of injury and infection 24–29 . Also, anti‐KC neutralizing monoclonal antibody (mAb) and/or anti‐MIP‐2 neutralizing mAb suppress neutrophil migration and inflammation when injected in vivo into murine models of inflammation 27,30,31 .…”