Basic Study
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World J Gastroenterol. Nov 21, 2022; 28(43): 6109-6130
Published online Nov 21, 2022. doi: 10.3748/wjg.v28.i43.6109
Differential analysis of intestinal microbiota and metabolites in mice with dextran sulfate sodium-induced colitis
Jia-Li Wang, Xiao Han, Jun-Xiang Li, Rui Shi, Lei-Lei Liu, Kai Wang, Yu-Ting Liao, Hui Jiang, Yang Zhang, Jun-Cong Hu, Li-Ming Zhang, Lei Shi
Jia-Li Wang, Xiao Han, Hui Jiang, Yang Zhang, Jun-Cong Hu, Li-Ming Zhang, Graduate School, Beijing University of Chinese Medicine, Beijing 100029, China
Jia-Li Wang, Xiao Han, Jun-Xiang Li, Rui Shi, Hui Jiang, Yang Zhang, Jun-Cong Hu, Li-Ming Zhang, Lei Shi, Department of Gastroenterology, Dongfang Hospital, Beijing University of Chinese Medicine, Beijing 100078, China
Lei-Lei Liu, College of Traditional Chinese Medicine, Beijing University of Chinese Medicine, Beijing 102488, China
Kai Wang, Department of Emergency, The First Teaching Hospital of Tianjin University of Traditional Chinese Medicine, Tianjin 300193, China
Yu-Ting Liao, Department of Geriatrics, Gulou Hospital of Traditional Chinese Medicine, Beijing 100009, China
Author contributions: Wang JL and Han X have contributed equally to this work, and they are co-first authors; Shi L and Li JX conceived and designed the study; Wang JL and Han X performed major experimental work; Wang JL and Shi R acquired and analyzed the results and edited the manuscript; Liu LL, Wang K, Liao YT, Jiang H, Zhang Y, Hu JC, and Zhang LM performed the experiments and statistical analyses; Shi L and Li JX revised the manuscript; All authors read and approved the final version of the manuscript.
Supported by the 13th Five-Year Plan for National Key R&D Program of China, No. 2018YFC1705405; Scientific Research Innovation Team Project of Beijing University of Chinese Medicine, No. 2019-JYB-TD004; New Faculty Startup Fund Program of BUCM, No. 2022-JYB-XJSJJ078; and National Natural Science Foundation of China, No. 82004113.
Institutional animal care and use committee statement: The animal study was reviewed and approved by the Animal Ethics Committee of Beijing University of Chinese Medicine. All animal experiments conformed to the internationally accepted principles for the care and use of laboratory animals (certificate No. SCXK-2019-0010, SPF Biotechnology Co., Ltd., Beijing, China; protocol No. BUCM-2020-01162, The Animal Ethics Committee of Beijing University of Chinese Medicine, Beijing, China).
Conflict-of-interest statement: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as potential conflict of interest.
Data sharing statement: All data are available upon reasonable request from LS, b01350@bucm.edu.cn.
ARRIVE guidelines statement: The authors have read the ARRIVE guidelines, and the manuscript was prepared and revised according to the ARRIVE guidelines.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: https://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: Lei Shi, MD, PhD, Research Associate, Department of Gastroenterology, Dongfang Hospital, Beijing University of Chinese Medicine, No. 6 Fangxingyuan Zone 1, Fangzhuang, Fengtai District, Beijing 100078, China. b01350@bucm.edu.cn
Received: July 12, 2022
Peer-review started: July 12, 2022
First decision: September 26, 2022
Revised: October 4, 2022
Accepted: November 2, 2022
Article in press: November 2, 2022
Published online: November 21, 2022
Processing time: 127 Days and 2.3 Hours
ARTICLE HIGHLIGHTS
Research background

The role of gut microbiota in ulcerative colitis (UC) cannot be ignored; however, most of current research is only based on the microbiota itself, ignoring microbiota metabolism. Microorganisms can reduce many biologically active substances, such as short-chain fatty acids, which have strong immuno-modulatory effects. Modern studies have reported that the destruction of the integrity of the mucus barrier is an early pathological change in UC. Different gut microbiota and their metabolites can influence the intestinal mucus barrier through different pathways, including altering epithelial structure, affecting mucin synthesis, secretion and degradation, and modulating immune responses.

Research motivation

At present, although many studies have confirmed the important role of gut microbiota in UC, the intricate relationship between microbiota and metabolites in UC has not been fully clarified. Association analysis of differential flora and their metabolites are required. It is worthwhile to conduct this study based on the intestinal mucus barrier to further reveal the potential differential biomarkers of UC.

Research objectives

The aim of the present study was to reveal the differential gut microbiota and metabolites that affect mucus in UC pathogenesis. The regulatory effect provides new evidence and new ideas for UC diagnosis.

Research methods

In the present study, based on the intestinal mucus barrier, taking the intestinal flora and metabolism as the breakthrough point, a combination of antibiotics was used to establish pseudo-aseptic mice, and the widely used dextran sodium sulfate was used to establish colitis mice. Disease severity, mucus-associated protein expression, bacterial 16s rDNA sequences, and non-targeted metabolomes of bacterial and bacterial colitis mice were examined. The tract microbiota and metabolites play potentially important roles in UC pathogenesis by affecting the mucus barrier.

Research results

This study found that: (1) The antibiotics combination can effectively remove the intestinal flora of mice, and reduce bacterial abundance, and α and β diversity, alter community structure, and successfully establish pseudo-aseptic mice; (2) Comparing the bacteria-bearing mice with the pseudo-aseptic mice, the bacteria-bearing mice had more severe colitis based on disease activity index, more severe intestinal mucosal damage, and more obvious intestinal mucus loss; (3) In the intestinal flora of colitis mice, Candidatus Stoquefichus, Anaerobiospirillum, Rikenellaceae RC9 gut group, Prevotellaceae Ga6A1 group, and Negativibacillus were significantly increased, while Candidatus Saccharimonas and Muribaculum were significantly decreased. The significantly up-regulated metabolites in the intestinal flora of colitis mice included 3-deoxyhexitol and ortho-phosphoserine, and the significantly down-regulated metabolites were galacturonic acid, etc.; and (4) Further enrichment analysis found that the above differential metabolites were mainly associated with amino acid and energy metabolism. Spearman correlation analysis found that 3-deoxyhexitol, o-phosphoserine, etc. were positively correlated with the occurrence and development of colitis, and galacturaldehyde was positively correlated with the occurrence and development of colitis. There was a significant positive correlation between galacturonic acid and lactulose and the reduction and colitis recovery.

Research conclusions

Candidatus Stoquefichus, Anaerobiospirillum, Rikenellaceae RC9 gut group, Prevotellaceae Ga6A1 group, and Negativibacillus are potentially emerging flora that induce or aggravate colitis, and Candidatus Saccharimonas and Muribaculum are potentially emerging flora that prevent or alleviate colitis. 3-Deoxyhexitol and o-phosphoserine may cause or aggravate colitis, while galacturonic acid may play a beneficial role in colitis alleviation and recovery. The differential metabolites of the flora are mainly enriched in the synthesis-related pathways of the rich-PTS sequence of the mucin MUC2 domain. They can affect the composition and function of mucus by regulating the expression of mucin, and finally act on the mucus barrier to induce aggravation or reduce colitis prevention.

Research perspectives

This study identified some less-reported differential gut microbiota and their metabolites in colitis, which could affect UC progression by modulating mucin synthesis, altering mucus status and the mucus barrier. In future studies, we will carry out in-depth transplantation experiments of fecal bacteria and metabolites to further verify the experimental conclusions of this study.