Rottlerin ameliorates DSS-induced colitis by improving intestinal barrier function via activation of the Epac-2/Rap-1 signaling pathway

OBJECTIVES Rottlerin, a pan PDE inhibitor, has a variety of pharmacological activities, including enhancing barrier function and mediating anti-inflammatory activity by changing the distribution of occludin and ZO-1. Nevertheless, the function of rottlerin on Crohn disease (CD) keep unknown. Our aim of the study is to investigate the role of rottlerin on CD-like colitis and its mechanism. METHODS Wild-type mice which were 8-10 weeks old were randomly divided into three treatment groups: (i) the normal feeding, no administration (control) group, (ii) the group administered 3% dextran sodium sulfate (DSS) alone, and (iii) the group administered rottlerin (100 mg/kg) and 3% DSS. In this study, the effect of rottlerin on the function and structure of the intestinal barrier was investigated, and the possible mechanism was discussed. We performed signaling pathway analysis and flow cytometry to identify the detailed mechanisms by which rottlerin (10 μg/mL) treatment inhibits cell growth arrest and the attenuation of TJ proteins in LPS-treated FHs 74 int cells. RESULTS Rottlerin treatment significantly ameliorated colitis induced by DSS in WT mice, which was manifested by a decrease in inflammation score, the attenuation of inflammatory factors and the inhibition of destruction on intestinal barrier structure. Rottlerin enhanced the levels of occludin and ZO-1, and improved the function of intestinal barrier, which may have been why rottlerin ameliorated colitis in WT mice. The anti-inflammatory effect of rottlerin may be partly due to the activation of Epac-2/Rap-1 signaling. CONCLUSIONS Rottlerin may treat CD in humans via enhancing TJ proteins expression and improving the function of intestinal barrier.