Identification of OLA1 as a Novel Protein Target of Vitexin to Ameliorate Dextran Sulfate Sodium-Induced Colitis with Tissue Thermal Proteome Profiling

Vitexin, which exists in various medicinal plants and food sources, has recently received increasing attention because of its anti-inflammatory properties. This study aims to identify the protein target of vitexin that ameliorates dextran sulfate sodium (DSS)-induced colitis. The results showed that vitexin not only alleviated the clinical symptoms and colonic damage in mice with DSS-induced colitis but also suppressed the colonic production of inflammatory cytokines (IL-1β, IL-6, ICAM, and VCAM) and enhanced the expression of barrier-associated proteins (ZO-1, Occludin, and E-cadherin). Based on tissue thermal proteome profiling (Tissue-TPP) and molecular docking, OLA1 was creatively identified as a potential protein target for vitexin. Further siRNA-mediated knockdown of the OLA1 gene in Caco-2 cells demonstrated the ability of OLA1 to increase Nrf2 protein expression and, thus, mediated the anti-inflammatory effects of vitexin. Interaction of the OLA1-vitexin complex with Keap1 protein to disrupt the Keap1-Nrf2 interaction may be required for activating Nrf2. Our findings revealed a novel role for OLA1 as a protein target of vitexin that contributes to its anti-inflammatory action by activating Nrf2, which may provide a promising molecular mechanism for novel therapeutic strategies to treat colitis and the associated systemic inflammation.