A sphingosine 1-phosphate receptor agonist ameliorates animal model of vasculitis

Sphingosine 1-phosphate (S1P) is a bioactive lipid that binds to cell surface receptors (S1P_1-5). In this study, we examined the effect of S1P₁ agonist, ONO-W061, on murine Candida albicans water-soluble fraction (CAWS)-induced vasculitis.

Mice were administered ONO-W061, and the number of peripheral blood cells was counted. Vasculitis was induced by an intraperitoneal injection of CAWS. Expression of S1P receptors and CXCL1 was analyzed by quantitative RT-PCR. ONO-W061 was orally administered, and vasculitis was evaluated histologically. Number of neutrophils, macrophages and T cells in the vasculitis tissue was counted using flow cytometry. Production of chemokines from S1P-stimulated human umbilical vein endothelial cells (HUVECs) was measured by ELISA.

Number of peripheral blood lymphocytes was decreased by ONO-W061. Expression of CXCL1 and S1P₁ was enhanced in CAWS-induced vasculitis tissue. Vasculitis score, CXCL1 and number of neutrophils in the vasculitis tissue were lower in ONO-W061-treated mice. Treatment of HUVECs with S1P upregulated the production of CXCL1 and IL-8 in vitro, and this was inhibited by ONO-W061.

ONO-W061 significantly improved CAWS-induced vasculitis. This effect may be partly exerted through the inhibited production of chemokines by endothelial cells, which in turn could induce neutrophil recruitment into inflamed vessels.