A novel sphingosine 1-phosphate receptor agonist, 2-amino-2-propanediol hydrochloride (KRP-203), regulates chronic colitis in interleukin-10 gene-deficient mice.

Current treatments for patients with Crohn's disease (CD) are based on recent advances in elucidating the pathophysiology of the disease. A satisfactory therapeutic strategy has not been well established. A new sphingosine 1-phosphate (S1P) receptor agonist, 2-amino-2-propanediol hydrochloride (KRP-203), has been developed for immunomodulation in autoimmune diseases and organ transplantation. We aimed to evaluate the efficacy and potency of KRP-203 on the treatment of chronic colitis in an interleukin (IL)-10 gene-deficient (IL-10(-/-)) mouse model. KRP-203 agonistic activity on S1P receptor was assessed in vitro. KRP-203 was administered for 1 or 4 weeks to IL-10(-/-) mice with clinical signs of colitis. The histological appearance of the colon and the numbers, phenotype, and cytokine production of lymphocytes were compared with a control group. KRP-203 treatment was effective in preventing body weight loss in the IL-10(-/-) colitis model. One-week administration resulted in the sequestration of circulating lymphocytes within the secondary lymphoid tissues. After 4 weeks of treatment, highly significant reductions were observed in number of CD4(+) T cell and B220(+) B cell subpopulations in the lamina propria of the colon and peripheral blood. KRP-203 obviously inhibited the production of interferon-gamma, IL-12, and tumor necrosis factor-alpha by the colonic lymphocytes, but had no influence on IL-4 production. KRP-203 significantly inhibits ongoing IL-10(-/-) colitis in part through decreasing the infiltration of lymphocytes at inflammatory sites and by blocking T-helper 1 cytokine production in the colonic mucosa. Therefore, the possibility arises that KRP-203 plays a potential role in control of chronic colitis.