Human umbilical cord mesenchymal stromal cell-derived exosomes alleviate antibiotic-induced intestinal barrier damage by regulating autophagy via the S100G/mTOR signaling pathway.

BACKGROUND

Antibiotics are a double-edged sword. Long-term, broad-spectrum, and high-dose antibiotic use can lead to the occurrence of related diseases, particularly attracting attention in the context of intestinal barrier damage. However, current clinical treatments remain suboptimal. Human umbilical cord mesenchymal stromal/stem cell-derived exosomes (HucMSCs-Exo) have demonstrated therapeutic efficacy in tissue repair and inflammatory bowel diseases. However, studies on their role in antibiotic-induced intestinal barrier damage remain limited.

OBJECTIVE

This study aims to investigate the therapeutic effects and underlying mechanisms of HucMSCs-Exo in treating antibiotic-induced intestinal mucosal barrier damage.

METHODS

A mouse model of antibiotic-induced intestinal barrier damage was established by administering clindamycin hydrochloride via gavage for 28 consecutive days in C57BL/6 male mice. The therapeutic effects of HucMSCs-Exo were evaluated through intraperitoneal injections at low and high concentrations every other day. Transcriptomic sequencing and other techniques were used to identify target genes and mechanistic pathways involved in HucMSCs-Exo mediated repair of intestinal mucosal barrier damage. Finally, the findings were validated in vitro using human colonic epithelial NCM460 cells.

RESULTS

The in vivo mouse experiments demonstrated that HucMSCs-Exo effectively alleviated antibiotic-induced intestinal barrier damage. Both low- and high-concentration exosome treatments improved the antibiotic-induced reduction in body weight gain, shortened colon length,disrupted intestinal epithelial continuity, increased permeability owing to microvilli structural damage, and decreased expression of tight junction proteins (ZO-1, Occludin, and Claudin-1). The in vitro cell experiments further showed that both low- and high-concentration exosome treatments restored antibiotic-induced reductions in cell proliferation and migration, as well as increased autophagy and apoptosis, with the high-concentration group showing significant differences (p < 0.05). Transcriptomic analysis of mouse colonic tissues revealed that differentially expressed genes were enriched in autophagy-related and apoptosis-related pathways, with S100G identified as a potential target gene of HucMSCs-Exo. Knockdown of the S100G gene in NCM460 cells yielded results consistent with the HucMSCs-Exo treatment group, indicating that HucMSCs-Exo exerts its effects by promoting mTOR phosphorylation, thereby inhibiting excessive autophagy.

CONCLUSIONS

HucMSCs-Exo alleviates antibiotic-induced intestinal mucosal barrier damage by inhibiting excessive autophagy-mediated apoptosis via the S100G/mTOR signaling pathway. Our findings elucidate the role and mechanism of exosomes in antibiotic-induced intestinal mucosal barrier damage, providing new insights for the therapeutic potential of exosomes in related fields.