Mechanism study of 6-sialyllactose alleviates immune checkpoint inhibitor-induced colitis in mouse
10.3760/cma.j.cn101480-20240219-00023
- VernacularTitle:6-唾液酸乳糖减轻小鼠免疫检查点抑制剂相关肠炎的机制研究
- Author:
Ke LI
1
;
Jiamin DONG
;
Xinyi YANG
;
Jinling MO
;
Wuming SHEN
;
Jingting JIANG
;
Wenting ZHANG
Author Information
1. 武进中医医院病理科，常州 213161
- Publication Type:Journal Article
- Keywords:
Immune checkpoint inhibitor-induced colitis;
6-sialyllactose;
16S rDNA sequencing;
Human milk oligosaccharide;
Intestinal inflammation
- From:
Chinese Journal of Inflammatory Bowel Diseases
2024;08(6):440-449
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To investigate the mechanism of 6-sialyllactose (6-SL) in interfering the immune checkpoint inhibitor-induced colitis (ICIC) through the bacterial 16S rDNA sequencing.Methods:BALB/c mice were randomly divided into the normal control (NC) group ( n = 7), dextran sulfate sodium (DSS) group ( n = 6), ICIC group ( n = 6), and ICIC+6-SL group ( n = 6). The DSS group was continuously fed with 3.5% DSS drinking water for 7 days to induce colonic inflammation; the ICIC group was administered cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4, 150 μg) intraperitoneally on days 0 and 4 in addition to 3.5% DSS drinking water to establish the ICIC mouse model; the ICIC+6-SL group was given 6-SL [150 mg/ (kg·d) ] by gavage simultaneously with the establishment of the ICIC model. Changes in mouse body weight and disease activity index (DAI) were statistically analyzed, and all mice were sacrificed on day 7 to observe gross and histopathological morphological changes in the colon and to tally histopathological scores; the fresh colonic feces were collected for 16S rDNA sequencing to statistically analyze the diversity and species differences in the microbiota of mice of each group. Results:The success rate of the ICIC model was 100%, with all mice surviving. At the endpoint of the study (day 7), compared with the NC and DSS groups, the ICIC group had lower mouse body weight ( P < 0.05), higher DAI ( P < 0.05), damaged integrity of colonic mucosal tissue, and typical ulcerative lesions; the ICIC+6-SL group showed significant alleviation of body weight loss, significantly lower DAI scores, and lower pathological scores compared to the ICIC group, with all differences being statistically significant (all P < 0.05). 16S rDNA sequencing of mouse intestinal feces indicated that the alpha diversity of colonic microbiota in the ICIC group was lower than that in the NC and DSS groups (both P < 0.05), while the ICIC+6-SL group had higher alpha diversity than the ICIC group ( P < 0.05). In beta diversity analysis, the ANOSIM statistical value R = 0.376, P = 0.001 for the PCoA analysis of colonic microbiota and a Stress value of 0.125, P = 0.001 for the NMDS analysis indicated differences in the composition of colonic microbiota among the groups, with the greatest difference between the NC and ICIC groups, and the ICIC+6-SL group's microbiota composition was closer to that of the NC group compared to the ICIC group. Lefse analysis and Kruskal-Wallis test-based differential microbiota analysis showed that at the phylum level, compared to the NC group, the abundance of Bacteroidetes was significantly reduced in the ICIC group, while Campilobacterota was increased, and 6-SL administration could increase the abundance of Bacteroidetes and Campilobacterota in the ICIC group. At the genus level, compared to other groups, the abundance of unclassified_f_Lachnospiraceae and norank_f_Muribaculaceae was the lowest in the ICIC group, while Helicobacter, Akkermansia, and Escherichia-Shigella were enriched. Compared to the ICIC group, the abundance of unclassified_f_Lachnospiraceae and norank_f_ Muribaculaceae was increased in the ICIC+6-SL group, while the abundance of Helicobacter and Escherichia-Shigella was significantly suppressed. Conclusions:6-SL, an oligosaccharide derived from human milk, alleviates intestinal inflammatory injury in ICIC mice, reducing disease activity. This beneficial effect may be related to its regulation of gut microbiota profiling, an increased diversity of microbiota, a restoration of Bacteroidetes, and an inhibition of the growth advantage of pathogenic bacteria such as Helicobacter and Escherichia-Shigella.
