Cell subtypes and immune dysfunction in peritoneal fluid of endometriosis revealed by single-cell RNA-sequencing

Abstract

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.

Drosophila, a powerful model to study virus-host interactions and pathogenicity in the fight against SARS-CoV-2

“…Notably, most signaling pathways are not only conserved from fly to human, but many have been first identified and studied in flies [ 22 ]. In fact, a remarkable 90% of human proteins in the SARS-CoV-2 human interactome [ 1 ] are conserved between flies and humans [ 23 ] (Fig. 1 B).…”

“…A recent publication from our group surveyed 12 SARS-CoV-2 proteins in flies, prioritized by their predicted likelihood to instigate pathogenic host interactions [ 23 ]. Similar to the study above, we studied the proteins in multiple tissues, in this case muscle and trachea (fly equivalent of the lung); both tissues are affected in COVID-19.…”

“…Similar to the study above, we studied the proteins in multiple tissues, in this case muscle and trachea (fly equivalent of the lung); both tissues are affected in COVID-19. Notably, the SARS-CoV-2 genes found to convey highest pathogenicity (i.e., Nsp6 , Orf6 and Orf7a ) in the in vitro human cell culture (HEK 293 T) model were also most pathogenic in our in vivo transgenic flies system [ 23 , 62 ]. In our hands, system-wide overexpression of protein SARS-CoV-2 Orf3a ( Tub-Gal4 ) reduced overall lifespan [ 23 ] but did not increase early lethality (death prior to eclosion) as observed when SARS-CoV-2 Orf3a was overexpressed in the fly central nervous system ( elav-Gal4 ) [ 61 ].…”

“…Notably, the SARS-CoV-2 genes found to convey highest pathogenicity (i.e., Nsp6 , Orf6 and Orf7a ) in the in vitro human cell culture (HEK 293 T) model were also most pathogenic in our in vivo transgenic flies system [ 23 , 62 ]. In our hands, system-wide overexpression of protein SARS-CoV-2 Orf3a ( Tub-Gal4 ) reduced overall lifespan [ 23 ] but did not increase early lethality (death prior to eclosion) as observed when SARS-CoV-2 Orf3a was overexpressed in the fly central nervous system ( elav-Gal4 ) [ 61 ]. In line with previous studies of human viruses in fly, orthology analysis revealed astounding levels (90%) of conservation for the SARS-CoV-2 virus-host interactome between humans and flies [ 23 ] (Fig.…”

“…In our hands, system-wide overexpression of protein SARS-CoV-2 Orf3a ( Tub-Gal4 ) reduced overall lifespan [ 23 ] but did not increase early lethality (death prior to eclosion) as observed when SARS-CoV-2 Orf3a was overexpressed in the fly central nervous system ( elav-Gal4 ) [ 61 ]. In line with previous studies of human viruses in fly, orthology analysis revealed astounding levels (90%) of conservation for the SARS-CoV-2 virus-host interactome between humans and flies [ 23 ] (Fig. 1 B).…”