Microbiota-derived I3A protects the intestine against radiation injury by activating AhR/IL-10/Wnt signaling and enhancing the abundance of probiotics

ABSTRACT

The intestine is prone to radiation damage in patients undergoing radiotherapy for pelvic tumors. However, there are currently no effective drugs available for the prevention or treatment of radiation-induced enteropathy (RIE). In this study, we aimed at investigating the impact of indole-3-carboxaldehyde (I3A) derived from the intestinal microbiota on RIE. Intestinal organoids were isolated and cultivated for screening radioprotective tryptophan metabolites. A RIE model was established using 13 Gy whole-abdominal irradiation in male C57BL/6J mice. After oral administration of I3A, its radioprotective ability was assessed through the observation of survival rates, clinical scores, and pathological analysis. Intestinal stem cell survival and changes in the intestinal barrier were observed through immunofluorescence and immunohistochemistry. Subsequently, the radioprotective mechanisms of I3A was investigated through 16S rRNA and transcriptome sequencing, respectively. Finally, human colon cancer cells and organoids were cultured to assess the influence of I3A on tumor radiotherapy. I3A exhibited the most potent radioprotective effect on intestinal organoids. Oral administration of I3A treatment significantly increased the survival rate in irradiated mice, improved clinical and histological scores, mitigated mucosal damage, enhanced the proliferation and differentiation of Lgr5⁺ intestinal stem cells, and maintained intestinal barrier integrity. Furthermore, I3A enhanced the abundance of probiotics, and activated the AhR/IL-10/Wnt signaling pathway to promote intestinal epithelial proliferation. As a crucial tryptophan metabolite, I3A promotes intestinal epithelial cell proliferation through the AhR/IL-10/Wnt signaling pathway and upregulates the abundance of probiotics to treat RIE. Microbiota-derived I3A demonstrates potential clinical application value for the treatment of RIE.

KEYWORDS:

• Radiotherapy
• gastrointestinal tract toxicity
• gut microbiota
• tryptophan metabolites
• indole-3-carboxaldehyde
• intestinal stem cells

Acknowledgments

We would like to extend our gratitude to the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD) and Jiangsu Provincial Key Laboratory of Radiation Medicine and Protection for their support during this study.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Author contributions statement

YT and ML conceived and designed the study. LWX and SC coordinated and performed most experimental work. HYL and FLT performed histopathological examination. RQZ performed statistical analyses. ML and LWX wrote the manuscript, and YT provided critical review.

Data availability statement

Research data are available at https://www.ncbi.nlm.nih.gov/bioproject/PRJNA1020984/ and https://www.ncbi.nlm.nih.gov/bioproject/PRJNA1020982/.

Supplementary material

Supplemental data for this article can be accessed online at https://doi.org/10.1080/19490976.2024.2347722

Additional information

Funding

This work was supported by the National Natural Science Foundation of China (82192884), the Suzhou Radiotherapy Clinical Medical Center (Szlcyxzx202103), the Suzhou Administration of Science and Technology (SKY2023121), Key Medical Discipline Construction Unit of Jiangsu Province for the 14th Five-year plan (JSDW202236), Young Talent Support Project of the 2th Affiliated Hospital of Soochow University (XKTJ-RC202007), Science Foundation of Jiangsu Health Commission (M2021081), Research project of medical talent of Suzhou (GSWS2021025), Extracurricular scientific research projects for students at Suzhou Medical College of Soochow University (2022YXYKWKY064), Jiangsu Province College Student Innovation and Entrepreneurship Training Program Project (202310285167Y) and Postgraduate Research & Practice Innovation Program of Jiangsu Province (KYCX22_3221).