AUTHOR=Zheng Cihua , Zhong Yuchun , Xie Jian , Wang Zhuoya , Zhang Wenming , Pi Yiming , Zhang Wenjun , Liu Li , Luo Jun , Xu Wei 

TITLE=Bacteroides acidifaciens and its derived extracellular vesicles improve DSS-induced colitis

JOURNAL=Frontiers in Microbiology

VOLUME=14

YEAR=2023

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2023.1304232

DOI=10.3389/fmicb.2023.1304232

ISSN=1664-302X

ABSTRACT=<sec><title>Introduction</title><p>“Probiotic therapy” to regulate gut microbiota and intervene in intestinal diseases such as inflammatory bowel disease (IBD) has become a research hotspot. <italic>Bacteroides acidifaciens</italic>, as a new generation of probiotics, has shown beneficial effects on various diseases.</p></sec><sec><title>Methods</title><p>In this study, we utilized a mouse colitis model induced by dextran sodium sulfate (DSS) to investigate how B. acidifaciens positively affects IBD. We evaluated the effects of<italic>B. acidifaciens</italic>, fecal microbiota transplantation, and bacterial extracellular vesicles (EVs) on DSS-induced colitis in mice. We monitored the phenotype of mouse colitis, detected serum inflammatory factors using ELISA, evaluated intestinal mucosal barrier function using Western blotting and tissue staining, evaluated gut microbiota using 16S rRNA sequencing, and analyzed differences in EVs protein composition derived from <italic>B. acidifaciens</italic> using proteomics to explore how <italic>B. acidifaciens</italic> has a positive impact on mouse colitis.</p></sec><sec><title>Results</title><p>We confirmed that <italic>B. acidifaciens</italic> has a protective effect on colitis, including alleviating the colitis phenotype, reducing inflammatory response, and improving intestinal barrier function, accompanied by an increase in the relative abundance of <italic>B. acidifaciens</italic> and Ruminococcus callidus but a decrease in the relative abundance of <italic>B. fragilis</italic>. Further fecal bacterial transplantation or fecal filtrate transplantation confirmed the protective effect of eosinophil-regulated gut microbiota and metabolites on DSS-induced colitis. Finally, we validated that EVs derived from <italic>B. acidifaciens</italic> contain rich functional proteins that can contribute to the relief of colitis.</p></sec><sec><title>Conclusion</title><p>Therefore, <italic>B. acidifaciens</italic> and its derived EVs can alleviate DSS-induced colitis by reducing mucosal damage to colon tissue, reducing inflammatory response, promoting mucosal barrier repair, restoring gut microbiota diversity, and restoring gut microbiota balance in mice. The results of this study provide a theoretical basis for the preclinical application of the new generation of probiotics.</p></sec>