A New Rip2 Kinase Inhibitor for the Treatment of Intestinal Inflammation (169.5)

Abstract

Abstract AIM: RIP2 is a critical mediator of NLRs signaling for innate immune activation. GEF-H1 interacts with NLRs and is responsible for initiating tyrosine phosphorylation of RIP2 required for the activation of NF-κB. We identified DCAM-253, 2-dialkylamino-9-indazolyl-purine, as a potent small molecule tyrosine kinase inhibitor of Rip2. Results: Gene specific siRNA mediated knockdown and expression of signaling intermediates in macrophages, and HEK293 cells was used to determine the mechanisms by which DCAM-253 inhibits Rip2 mediated induction of cytokine expression. DCAM-253 prevented the recruitment of GEF-H1 to the Rip2/NLR signaling complexes and subsequent tyrosine phosphorylation of Rip2. DCAM-253 inhibited TNFα production induced by GEF-H1 dependent NLR activation. DCAM-253 was able to protect mice from intestinal inflammation induced by epithelial barrier disruption and microbial defense activation in the DSS-induced colitis model. Contol group Mice presented with transmural leukocyte infiltration and crypt damage with tissue destruction indicating severe persistent colitis. In contrast, low cellular infiltration and intact intestinal epithelium were observed in the colon sections of mice treated with 2 oral doses of DCAM-253. Conclusion: We have identified a new small molecule inhibitor, which protects mice from colitis and promotes mucosal recovery by preventing Rip2 tyrosine phosphorylation upon intestinal barrier disruption and subsequent innate immune activation.