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

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.