AUTHOR=Liu Liyun , Xu Mingchao , Lan Ruiting , Hu Dalong , Li Xianping , Qiao Lei , Zhang Suping , Lin Xiaoying , Yang Jing , Ren Zhihong , Xu Jianguo 

TITLE=Bacteroides vulgatus attenuates experimental mice colitis through modulating gut microbiota and immune responses

JOURNAL=Frontiers in Immunology

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2022.1036196

DOI=10.3389/fimmu.2022.1036196

ISSN=1664-3224

ABSTRACT=<sec><title>Introduction</title><p><italic>Bacteroides vulgatus</italic> is one of the predominant <italic>Bacteroides</italic> species in the human gut and exerts a series of beneficial effects. The aim of this study was to investigate the protective role of <italic>B. vulgatus</italic> Bv46 in a dextran sodium sulfate (DSS) induced colitis mouse model.</p></sec><sec><title>Methods</title><p>Female C57BL/6J mice were given 3% DSS in drinking water to induce colitis and simultaneously treated with <italic>B. vulgatus</italic> Bv46 by gavage for 7 days. Daily weight and disease activity index (DAI) of mice were recorded, and the colon length and histological changes were evaluated. The effects of <italic>B. vulgatus</italic> Bv46 on gut microbiota composition, fecal short chain fatty acids (SCFAs) concentration, transcriptome of colon, colonic cytokine level and cytokine secretion of RAW 264<sub>·</sub>7 macrophage cell line activated by the lipopolysaccharide (LPS) were assessed.</p></sec><sec><title>Results and Discussion</title><p><italic>B. vulgatus</italic> Bv46 significantly attenuated symptoms of DSS-induced colitis in mice, including reduced DAI, prevented colon shortening, and alleviated colon histopathological damage. <italic>B. vulgatus</italic> Bv46 modified the gut microbiota community of colitis mice and observably increased the abundance of <italic>Parabacteroides</italic>, <italic>Bacteroides</italic>, <italic>Anaerotignum</italic> and <italic>Alistipes</italic> at the genus level. In addition, <italic>B. vulgatus</italic> Bv46 treatment decreased the expression of colonic TNF-α, IL-1β and IL-6 in DSS-induced mouse colitis <italic>in vivo</italic>, reduced the secretion of TNF-α, IL-1β and IL-6 in macrophages stimulated by LPS <italic>in vitro</italic>, and downregulated the expression of <italic>Ccl19, Cd19, Cd22, Cd40</italic> and <italic>Cxcr5</italic> genes in mice colon, which mainly participate in the regulation of B cell responses. Furthermore, oral administration of <italic>B. vulgatus</italic> Bv46 notably increased the contents of fecal SCFAs, especially butyric acid and propionic acid, which may contribute to the anti-inflammatory effect of <italic>B. vulgatus</italic> Bv46. Supplementation with <italic>B. vulgatus</italic> Bv46 serves as a promising strategy for the prevention of colitis.</p></sec>