TRIP6 promotes inflammatory damage via the activation of TRAF6 signaling in a murine model of DSS-induced colitis.

ABSTRACT

BACKGROUND: TRIP6 is a zyxin family member that serves as an adaptor protein to regulate diverse biological processes. In prior reports, TRIP6 was shown to play a role in regulating inflammation. However, its in vivo roles and mechanistic importance in colitis remain largely elusive. Herein, we therefore employed TRIP6-deficient (TRIP6-/-) mice in order to explore the mechanistic importance of TRIP6 in a dextran sodium sulfate (DSS)-induced model of murine colitis. FINDINGS: Wild-type (TRIP6+/+) mice developed more severe colitis following DSS-mediated disease induction relative to TRIP6-/- mice, as evidenced by more severe colonic inflammation and associated crypt damage. TRIP6 expression in wild-type mice was significantly elevated following DSS treatment. Mechanistically, TRIP6 binds to TRAF6 and enhances oligomerization and autoubiquitination of TRAF6. This leads to the activation of NF-κB signaling and the expression of pro-inflammatory cytokines such as TNFα and IL-6, in the in vivo mouse model of colitis. CONCLUSIONS: These in vivo data demonstrate that TRIP6 serves as a positive regulator of DSS-induced colitis through interactions with TRAF6 resulting in the activation of inflammatory TRAF6 signaling, highlighting its therapeutic promise as a protein that theoretically can be targeted to prevent or treat colitis.