Non-enterotoxin-producing Bacteroides fragilis inhibits TNF-α-induced inflammatory response in colonic epithelial cells by down-regulating the NF-κB signaling pathway
10.3760/cma.j.cn112309-20240717-00263
- VernacularTitle:非产肠毒素型脆弱拟杆菌通过下调NF-κB通路抑制TNF-α诱导的结肠上皮细胞炎症反应
- Author:
Qiuyue HE
1
;
Qiuling HUANG
;
Jian MAO
;
Yongshi ZHAO
;
Yingxuan CHEN
;
Yan ZHANG
;
Yan DU
Author Information
1. 昆明医科大学第一附属医院医学检验科，云南省检验医学重点实验室，云南省医学检验临床医学研究中心，昆明 650032
- Keywords:
Non-enterotoxin-producing Bacteroides fragilis;
Colitis;
NF-κB signaling pathway;
Inflammatory response
- From:
Chinese Journal of Microbiology and Immunology
2024;44(10):829-837
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To investigate the mechanism by which non-enterotoxin-producing Bacteroides fragilis (NTBF) inhibits TNF-α-induced inflammatory responses in human normal colonic epithelial cells hcoEPIC, and explore new probiotic therapies for the prevention and treatment of colitis. Methods:The co-culture system of NTBF and hcoEPIC cells was established, and the adhesion and invasion ability of NTBF were detected, respectively. TNF-α was added to induce cellular inflammation after 4 h of co-culture of NTBF and hcoEPIC cells, and cell survival and apoptosis were detected by the CCK-8 assay and the AnnexinⅤ-FITC/PI assay respectively after 24 h. Key proteins of the NF-κB signalling pathway in hcoEPIC cells in different treatment groups were detected by Western blot and RT-qPCR, and the expression of downstream cytokines of this pathway incluing IL-1β, TNF-α and IL-10 were detected by ELISA. The effect of NTBF intervention on dextran sodium sulfate(DSS)-induced colitis mice was assessed by in vivo animal experiments. Results:NTBF adhered to hcoEPIC cells, and was non-toxic to the cells. Compared with control group, NTBF treatment alone did not affect cell survival and apoptosis of hcoEPIC cells ( P>0.05), but significantly reduced cell damage and apoptosis induced by TNF-α ( P<0.05); Compared with the TNF-α treatment alone group, the expression levels of p-NF-κB p65 and p-IκBα protein as well as NF-κB and IκBα mRNA were significantly reduced ( P<0.05); the production of IL-1β and TNF-α in the cell supernatant was reduced and the release of IL-10 was increased ( P<0.05). Animal experiments demonstrated that NTBF was indeed effective in alleviating DSS-induced colitis in ulcerative colitis model mice, which was mainly manifested by inhibiting weight loss, lowering DAI scores, improving colonic shortening, and attenuating colonic pathological damage in colitis-induced mice. Conclusions:NTBF may inhibit TNF-α-induced inflammatory responses in colonic epithelial cells by down-regulating the NF-κB pathway.
