Basic Study
Copyright ©The Author(s) 2022. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Feb 7, 2022; 28(5): 532-546
Published online Feb 7, 2022. doi: 10.3748/wjg.v28.i5.532
Effect of Bacillus subtilis, Enterococcus faecium, and Enterococcus faecalis supernatants on serotonin transporter expression in cells and tissues
Yi-Ming Chen, Ying Li, Xin Wang, Ze-Lan Wang, Jun-Jie Hou, Shuai Su, Wei-Long Zhong, Xin Xu, Jie Zhang, Bang-Mao Wang, Yu-Ming Wang
Yi-Ming Chen, Ying Li, Xin Wang, Ze-Lan Wang, Jun-Jie Hou, Shuai Su, Wei-Long Zhong, Xin Xu, Jie Zhang, Bang-Mao Wang, Yu-Ming Wang, Department of Gastroenterology and Hepatology, Tianjin Medical University General Hospital, Tianjin 300052, China
Author contributions: Wang YM, Wang BM and Zhang J conceived and designed the study; Chen YM and Wang ZL conducted the experiments; Li Y and Wang X rote the manuscript; Su S, Hou JJ, Zhong WL and Xu X analyzed data; Chen YM and Li Y contributed equally to this work; all authors read and approved the manuscript.
Supported by the National Natural Science Foundation of China, No. 81570489; and the Youth Project of National Natural Science Foundation of China, No. 81900487.
Institutional review board statement: This study was reviewed and approved by the Ethics Committee of Tianjin Medical University General Hospital (IRB2021-WZ-100).
Institutional animal care and use committee statement: All procedures involving animals were reviewed and approved by the Institutional Animal Care and Use Committee of the Institute of Radiation Medicine, Chinese Academy of Medical Sciences (Tianjin, China) (IACUC Protocol No. IRM-DWLL-2021142).
Conflict-of-interest statement: The authors have no conflicts of interest to declare.
Data sharing statement: No additional data are available.
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: http://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: Yu-Ming Wang, MD, Chief Doctor, Department of Gastroenterology and Hepatology, Tianjin Medical University General Hospital, No. 154 Anshan Road, Heping District, Tianjin 300052, China. yumingwangbest@163.com
Received: July 21, 2021
Peer-review started: July 21, 2021
First decision: October 3, 2021
Revised: October 16, 2021
Accepted: January 6, 2022
Article in press: January 6, 2022
Published online: February 7, 2022
Processing time: 187 Days and 18.8 Hours
ARTICLE HIGHLIGHTS
Research background

It is worthwhile to explore which effective ingredients in the supernatants of Bacillus subtilis, Enterococcus faecium, and Enterococcus faecalis and which signaling pathways are regulating serotonin transporter (SERT) expression further.

Research motivation

The supernatants of B. subtilis, E. faecium, and E. faecalis can upregulate SERT expression in intestinal epithelial cells and the intestinal tissues in the rat model of PI-IBS. And combined supernatants of B. subtilis and E. faecalis was more efficacious than single supernatant.

Research objectives

The levels of SERT (at post-treatment 12 and 24 h) were significantly elevated in Caco-2 cells treated with B. subtilis supernatant compared with those in the control group (aP < 0.05). Those levels were markedly upregulated in Caco-2 cells stimulated with E. faecium and E. faecalis supernatants at 24 h (aP < 0.05). In addition, the SERT expression in groups B, C and D was significantly higher than that in group A in the 2nd wk (aP < 0.05). Increased SERT expression was found only in group D in the 3rd wk (aP < 0.05). However, there was no significant difference in the SERT expression between the groups in the last week (P > 0.05).

Research methods

Caco-2 and HT-29 cells were stimulated with probiotic culture supernatants for 12 and 24 h, respectively. A rat (male Sprague-Dawley rat) model of post-infectious irritable bowel syndrome (PI-IBS) was constructed and the rats were treated with PBS (group A) and three probiotics culture supernatants (groups B, C, and D) for 4 wk. The levels of SERT were detected by quantitative PCR and western blotting.

Research results

The present study aimed to explore whether B. subtilis, E. faecium, and E. faecalis supernatants could upregulate SERT expression in vitro and in vivo.

Research conclusions

5-HT and SERT contribute significantly to the development of IBS. Whether the supernatants of B. subtilis, E. faecium, and E. faecalis can improve gastrointestinal sensation and movement by regulating SERT expression needs to be clarified. The research is significant to the treatment of IBS patients with lower expression level of SERT or with symptoms of diarrhea.

Research perspectives

IBS is a functional gastrointestinal disorder, of which the onset and development are associated with serotonin and SERT. Recent studies have shown that B. subtilis, E. faecium, and E. faecalis play important roles in the clinical treatment of IBS. However, the underlying mechanism of therapeutic effects on IBS remains elusive and requires additional research.