Ulcerative colitis is an
inflammatory bowel disease characterized by
inflammation in the mucosal and submucosal layers of the colon.
Obesity is closely related to the occurrence and progression of
colitis. The most plausible mechanism linking
obesity and
colitis is an excessive adipogenesis-related inflammatory response, which causes mucosal dysfunction.
Obesity and
colitis are linked by several etiologic mechanisms, including excessive adipogenesis, lipotoxicity, pro-inflammatory
adipokines/
cytokines, macrophage polarization, oxidative stress, endoplasmic reticulum (ER) stress, and gut microbiota. These low-grade enteric
inflammations cause mucosal layer damage, especially goblet cell dysfunction through
mucin 2 (MUC2) misfolding, ultimately leading to
colitis. Inhibiting the inflammatory response can be the most effective approach for treating
obesity-related
colitis. We focused on the anti-inflammatory effects of
polyphenols in Protaectia brevitas larvae. The P. brevitas was prepared as a low molecular
protein hydrolysate (PHPB) to increase the concentration of anti-inflammatory molecules. In the current study, we investigated the anti-inflammatory effect of PHPB in an
obesity-induced
colitis mouse model. Compared with the high-fat diet (HFD) group, the group treated with PHPB exhibited reduced body/organ/fat weight, appetite/food intake inhibition, hypolipidemic effect on ectopic fat, and anti-adipogenic mechanism through the AMPK signaling pathway. Furthermore, we observed attenuated expression of PPARγ and C/EBPα, inhibition of pro-inflammatory molecules, stimulation of anti-inflammatory molecules, probiotic-like effect against obesogenic gut microbiota, inhibition of macrophage polarization into M1, suppression of oxidative/ER stress, and reduction of Muc2
protein misfolding in colon. These diverse anti-inflammatory responses caused histological and functional recovery of goblet cells, eventually improving
colitis. Therefore, our findings suggest that the
protein hydrolysate of Protaetia brevitarsis can improve
obesity-related
colitis through its anti-inflammatory activities.