Cell-type-specific regulation of acute respiratory distress syndrome by P2RY6-expressing CD11c+ cells

Acute respiratory distress syndrome (ARDS) is a life-threatening inflammatory lung disorder characterized by excessive neutrophilic inflammation and increased microvascular permeability. We previously demonstrated the involvement of the G q -coupled P2Y 2 purinergic receptor (P2RY 2 ) in ARDS pathogenesis. Here, we investigated the contribution of the related purinergic receptor P2Y 6 (P2RY 6 ) and defined its cell-type-specific functions using a preclinical mouse model of ARDS. Wild-type female mice were treated with the selective P2RY 6 antagonist MRS2578 through intratracheal administration using prophylactic and therapeutic approaches, followed by lipopolysaccharide (LPS) challenge. The role of P2RY 6 was further evaluated in global P2ry 6 -deficient mice and conditional knockout models targeting specific cellular compartments. Bronchoalveolar lavage (BAL) samples were analyzed by flow cytometry and multiplex cytokine assays, and lung tissues were assessed by histological and immunohistochemical analyses. Pharmacological inhibition of P2RY 6 significantly reduced Ly6G + F4/80⁻ neutrophil accumulation, vascular leakage and pro-inflammatory cytokine and chemokine production in the ARDS model. Consistently, P2ry 6 -deficient mice exhibited reduced Ly6G + F4/80⁻ neutrophil recruitment and attenuated inflammatory responses following LPS challenge. Cell-type-specific deletion revealed that P2RY 6 deficiency in Vav-expressing hematopoietic cells and CD11c-expressing cells reproduced the protective phenotype observed in global P2ry 6 knockout mice. In contrast, P2RY 6 deletion in CD4 + T cells, Scgb1a1 -expressing airway epithelial cells or LysM-expressing myeloid cells did not significantly alter ARDS-associated inflammation. Collectively, our findings identify CD11c-expressing P2RY 6 + cells as critical regulators of ARDS pathogenesis and highlight P2RY 6 as a potential therapeutic target for controlling inflammatory lung injury.