P2RY4 and acute respiratory distress syndrome: These data highlight the possible role of P2RY2 in regulating ARDS in vivo. The expression of some other family members of purinergic receptors (P2rx1, P2rx4, P2rx7, P2ry4 and P2ry6) was also screened in BALF macrophages and neutrophils after LPS instillation in WT mice.