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* = Presenting author

P008 IL-34 antibody ameliorates experimental Colitis by alternating IL-12p40 expression in macrophages

T. Yoshino*, M. Matsuura, H. Nakase

Graduate School of Medicine, Kyoto University, Gastroenterology and Hepatology, Kyoto, Japan

Background

Previously, we reported the involvement of IL-34 in the pathophysiology of Crohn's disease. However, the effect of IL-34 antibody on colonic inflammation remains unclear.Therefore, the aim of this study is to examine the possibility of IL-34 as a therapeutic target cytokine using the murine colitis model.

Methods

1) Gene expression of IL-34 was evaluated in acute colitis of C57BL/6 mice with dextran sulfate sodium (DSS). To induce colitis in C57BL/6 mice, 3% DSS was provided ad libitum up to 5 days. On day 5, they were switched to normal drinking water. Mice were sacrificed on day 7. 2) To evaluate the possibility of IL-34 as a therapeutic target, the therapeutic effect of intraperitoneal administration of IL-34 antibody (R&D Systems, Inc., Minneapolis, MN) was studied using DSS-induced colitis model. Treatment with intraperitoneal administration of anti-IL-34 antibody (10 μ g/body) was performed from day 0 to day4, and mice were sacrificed at day 7. After sacrifice, colon length was evaluated and the severity of inflammation of colon was scored using a histological index. 3) To evaluate the effect of IL-34 on the function of macrophages, gene expressions of inflammatory cytokine were evaluated using peritoneal macrophages derived from C57BL/6 mice. Peritoneal macrophages were incubated with IL-34 (25ng/ml) for 24 hours followed by stimulation with LPS (1 μ g/ml) for 24 hours. After stimulation with LPS, gene expressions (TNF- α , IL-6, IL-12p40) were evaluated with real-time polymerase chain reaction (PCR).

Results

1) Gene expression of IL-34 in colonic tissue of mice with DSS-induced colitis was significantly higher than that in control mice. 2) In DSS-induced colitis model, colon length of IL-34 antibody group was significantly longer than that of control group. Histological score of IL-34 antibody group was significantly lower than that of control group. Moreover, gene expression of TNF- α and IL-12p40 in colon of IL-34 antibody group was lower than that of control group. 3) After stimulation with LPS, gene expression of IL-12p40 in IL-34 pretreated peritoneal macrophages was significantly higher than that without pretreatment of IL-34, despite there was no difference of gene expression of TNF- α and IL-6.

Conclusion

Our data suggested that IL-34 antibody ameliorated DSS-colitis by alternating IL-12p40 expression in macrophages.