Berberine Protects Mice Against Dextran Sulfate Sodium-Induced Colitis by Activating mTORC1 Pathway.

Berberine is a plant alkaloid that can be extracted from many Chinese herbs. It has been reported that berberine could protect mice from ulcerative colitis, but the mechanism remains unclear. The current study's aim was to determine the potential mechanism by which berberine exhibits its anti-inflammatory function. Mice with colitis induced by dextran sulfate sodium (DSS) were administered with berberine at 50 mg/kg by gavage. Berberine significantly increased the proportion of regulatory T cells (Treg cells). The targeted metabolomics analysis was then performed to find that glutamine and glutamate metabolism played an important role in the process of regulating immune response. mTORC1 pathway was reported to closely relate with glutamine metabolism. As a result, the relative expression levels of downstream effector genes of mTORC were further determined, and data obtained showed that berberine could significantly increase the relative expression levels of S6K1 and 4EBP1. In addition, rapamycin was used to inhibit mTORC1 signaling, and it was found that colon length, disease associated index (DAI), and proportion of Treg cells of mice in the rapamycin-DSS group were not different from those of mice in the rapamycin/berberine-DSS group. Together, these results suggest that berberine exhibits significant protective effects against DSS colitis by activating the mTORC1 pathway to increase the proportion of Treg cells.