A Spermidine Derivative Ameliorates Dextran Sulfate Sodium-Induced Colitis in Mice by Inhibiting the MAPK4/AKT Signaling Pathway

Ulcerative colitis (UC) is a chronic inflammatory bowel disease characterized by recurrent episodes and an inability to achieve a complete cure. The spermidine derivative (di- p -coumaroyl-caffeoyl spermidine, SPDD), as a key alkaloid, exhibits unique health benefits. However, it has not yet been reported whether SPDD can improve dextran sulfate sodium (DSS)-induced colitis in mice. Herein, we investigated the effects and mechanisms of SPDD on DSS-induced colitis in mice. SPDD was successfully purified from rose bee pollen and was found to have a protective effect on colitis, evidenced by reduced disease activity index (DAI) scores and colonic inflammation, increased colonic length and upregulated the expression of tight junction proteins (TJs) in the model ( p < 0.05). Importantly, the IL-17 signaling pathway showed significant enrichment by RNA sequencing (RNA-seq) technology with SPDD treatment, which resulted in the downregulation of MAPK4 expression ( p < 0.05). Furthermore, SPDD weakened the interaction between MAPK4 and AKT, resulting in a decrease in the phosphorylation level of AKT, thereby reducing the expression of IL-6, IL-1β, iNOS, and COX-2, and alleviating colitis ( p < 0.05). In addition, SPDD treatment also ameliorated TNF-α-induced inflammation in Caco-2 cells. Overall, our study demonstrated that SPDD reversed colonic inflammation in colitis mice through the MAPK4/AKT pathway and might be a promising candidate for UC intervention.