P2Y2 Receptor Regulates VCAM-1 Membrane and Soluble Forms and Eosinophil Accumulation during Lung Inflammation

ATP has been defined as a key mediator of asthma. In this study, we evaluated lung inflammation in mice deficient for the P2Y 2 purinergic receptor. We observed that eosinophil accumulation, a distinctive feature of lung allergic inflammation, was defective in OVA-treated P2Y 2 -deficient mice compared with OVA-treated wild type animals. Interestingly, the upregulation of VCAM-1 was lower on lung endothelial cells of OVA-treated P2Y 2 −/− mice compared with OVA-treated wild type animals. Adhesion assays demonstrated that the action of UTP on leukocyte adhesion through the regulation of endothelial VCAM-1 was abolished in P2Y 2 -deficient lung endothelial cells. Additionally, the level of soluble VCAM-1, reported as an inducer of eosinophil chemotaxis, was strongly reduced in the bronchoalveolar lavage fluid (BALF) of P2Y 2 -deficient mice. In contrast, we observed comparable infiltration of macrophages and neutrophils in the BALF of LPS-aerosolized P2Y 2 +/+ and P2Y 2 −/− mice. This difference could be related to the much lower level of ATP in the BALF of LPS-treated mice compared with OVA-treated mice. Our data define P2Y 2 as a regulator of membrane and soluble forms of VCAM-1 and eosinophil accumulation during lung inflammation.