Background
Endometriosis is a refractory and recurrent disease and it affects nearly 10% of reproductive-aged women and 40% of infertile patients. The commonly accepted theory for endometriosis is retrograde menstruation where endometrial tissues invade into peritoneal cavity and fail to be cleared due to immune dysfunction. Therefore, the comprehensive understanding of immunologic microenvironment of peritoneal cavity deserves further investigation for the previous studies mainly focus on one or several immune cells.
Results
High-quality transcriptomes were from peritoneal fluid samples of patients with endometriosis and control, and firstly subjected to 10 × genomics single-cell RNA-sequencing. We acquired the single-cell transcriptomes of 10,280 cells from endometriosis sample and 7250 cells from control sample with an average of approximately 63,000 reads per cell. A comprehensive map of overall cells in peritoneal fluid was first exhibited. We unveiled the heterogeneity of immune cells and discovered new cell subtypes including T cell receptor positive (TCR+) macrophages, proliferating macrophages and natural killer dendritic cells in peritoneal fluid, which was further verified by double immunofluorescence staining and flow cytometry. Pseudo-time analysis showed that the response of macrophages to the menstrual debris might follow the certain differentiation trajectory after endometrial tissues invaded into the peritoneal cavity, that is, from antigen presentation to pro-inflammation, then to chemotaxis and phagocytosis. Our analyses also mirrored the dysfunctions of immune cells including decreased phagocytosis and cytotoxic activity and elevated pro-inflammatory and chemotactic effects in endometriosis.
Conclusion
TCR+ macrophages, proliferating macrophages and natural killer dendritic cells are firstly reported in human peritoneal fluid. Our results also revealed that immune dysfunction happens in peritoneal fluid of endometriosis, which may be responsible for the residues of invaded menstrual debris. It provided a large-scale and high-dimensional characterization of peritoneal microenvironment and offered a useful resource for future development of immunotherapy.
Indian hedgehog (Ihh) signaling regulates endometrial receptivity and is an indispensable mediator of embryonic implantation. Hedgehog signaling is known to regulate autophagy, and aberrant regulation of autophagy is critically implicated in the pathogenesis of endometriosis and adenomyosis. However, potential dysregulation of Ihh signaling and its role in autophagy modulation in these diseases remain obscure. In this study, we found that components of Ihh signaling were significantly decreased, whereas the autophagy marker protein, LC3BII, was significantly increased in endometrial tissues of women with endometriosis or adenomyosis. Inhibition of Ihh signaling with the small molecule inhibitor, GANT61, or Gli1 silencing in primary endometrial stromal cells increased autophagic activity, as measured by the LC3 turnover assay and tandem mCherry-eGFP-LC3B fluorescence microscopy. Furthermore, we observed that GANT61 treatment significantly attenuated hydrogen peroxide-induced cell death, whereas disruption of autophagy with chloroquine diminished this effect. Collectively, these findings reveal that Ihh signaling is suppressed in endometrial tissues of patients with endometriosis or adenomyosis. This abnormal decrease may contribute to endometrial autophagy activation, which may promote aberrant survival of endometrial cells in ectopic sites in these two gynecological diseases.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.