Microbiota-derived genotoxin tilimycin generates colonic stem cell mutations

Area of Science:

• Microbiology
• Genetics
• Gastroenterology

Background:

• The gut microbiome plays a crucial role in intestinal health.
• Certain bacteria produce genotoxins that can harm host cells.
• Intestinal stem cells are vital for tissue repair and regeneration.

Purpose of the Study:

• To investigate the effects of the DNA-alkylating genotoxin tilimycin on intestinal stem cells.
• To understand the link between tilimycin-producing Klebsiella and colorectal stem cell mutations.
• To assess the impact of genotoxic bacteria on somatic genetic changes in the colon.

Main Methods:

• Spatial distribution and quantification of tilimycin metabolites in colonized mice.
• Analysis of genetic aberrations in colorectal stem cells using marker gene G6pd.
• Comparison of mutation frequencies in mice colonized with tilimycin-producing versus non-producing Klebsiella.

Main Results:

• Tilimycin accumulation was observed in Klebsiella-colonized mice.
• Loss of G6pd function indicated genetic damage in colorectal stem cells, forming monoclonal mutant crypts.
• Mice with tilimycin-producing Klebsiella showed significantly higher frequencies and burdens of somatic mutations.

Conclusions:

• Genotoxic Klebsiella species can induce somatic genetic alterations in the colon.
• Tilimycin-induced DNA damage to stem cells may contribute to disease susceptibility.
• Understanding these microbial genotoxic effects is crucial for human gut health.