Disrupted Tuzzerella abundance and impaired L-glutamine levels induce Treg accumulation in ovarian endometriosis: a comprehensive multi-omics analysis.

Introduction: The microbial community plays a crucial role in the pathological microenvironment. However, the structure of the microbial community within endometriotic lesions and its impact on the microenvironment is still limited.

Methods: All 55 tissue samples, including ovarian ectopic (OEMs) and normal (NE) endometrium, were subjected to 16S rRNA sequencing, metabolomic and proteomic analysis.

Results: We found the abundance of Tuzzerella is significantly lower in OEMs compared to NE tissue (p < 0.01). We selected samples from these two groups that exhibited the most pronounced difference in Tuzzerella abundance for further metabolomic and proteomic analysis. Our findings indicated that endometriotic lesions were associated with a decrease in L-Glutamine levels. However, proteomic analysis revealed a significant upregulation of proteins related to the complement pathway, including C3, C7, C1S, CLU, and A2M. Subsequent metabolic and protein correlation predictions demonstrated a negative regulation between L-Glutamine and C7. In vitro experiments further confirmed that high concentrations of Glutamine significantly inhibit C7 protein expression. Additionally, immune cell infiltration analysis, multiplex immunofluorescence, and multifactorial testing demonstrated a positive correlation between C7 expression and the infiltration of regulatory T cells (Tregs) in ectopic lesions, while L-Glutamine was found to negatively regulate the expression of chemotactic factors for Tregs.

Conclusion: In this study, we found a clear multi-omics pathway alteration, "Tuzzerella (microbe)-L-Glutamine (metabolite)-C7 (protein)," which affects the infiltration of Tregs in endometriotic lesions. Our findings provide insights into endometriosis classification and personalized treatment strategies based on microbial structures.