Activation of Purinergic P2Y2 Receptor Protects the Kidney Against Renal Ischemia and Reperfusion Injury in Mice.

Extracellular ATP plays an important role in renal physiology as well as the pathogenesis of acute kidney injury induced by renal ischemia and reperfusion (IR). Expression of the purinergic P2Y2 receptor has been shown on inflammatory and structural cells of the kidney, and P2Y2R is preferably activated by ATP (or UTP). Here, we investigated the molecular mechanism of P2Y2R during IR injury by using P2Y2R knockout (KO) mice and a selective P2Y2R agonist, MRS2768. After renal IR, P2Y2R KO mice showed greater increases in plasma creatinine, tubular damage and neutrophil infiltration, and significant induction of proinflammatory cytokines and apoptotic markers than wild-type (WT) mice. In contrast, treatment with MRS2768 reduced plasma creatinine levels, tubular damage and inflammation, and renal apoptosis in mice subjected to renal IR. In cultured human proximal tubular HK-2 cells, MRS2768 upregulated P2Y2R mRNA levels and decreased TNF-α/cycloheximide-induced apoptosis and inflammation. Importantly, P2Y2R activation by MRS2768 increased the phosphorylation of protein kinase C (PKC), Src, and phosphatidylinositol 3-kinase (PI3K)/Akt. In addition, the inhibition of PI3K/Akt abolished the protective effects of MRS2768 against TNF-α/cycloheximide-induced apoptosis and inflammation in HK-2 cells. In conclusion, activation of P2Y2R protects against tubular apoptosis and inflammation during renal IR via the PKC/Src/Akt pathway, suggesting P2Y2R is a promising therapeutic target for acute kidney injury.