P-797 Single-cell analysis sheds light on investigation of epithelial stem/progenitor cells in human endometrial organoid

Abstract Study question How to find endometrial epithelial stem cell (eeSC) in the human gland? Summary answer Endometrial organoid culture model combined with omics techniques can be a promising platform for investigating eeSC functions and gland development. What is known already stem/progenitor cells are thought involved regeneration, stromal having been extensively studied. On other hand, study of challenging due lack specific markers isolate examine their functional properties. In addition, vivo phenotype primary cannot maintained long duration two-dimensional culture. The development three-dimensional provides suitable alternatives studying eeSC, as they tailored biomimetic accurately recapitulate native scenario glandular cells. design, size, This basic science organoids. biopsies were performed on day 2 after injection chorionic gonadotrophin women undergoing vitro fertilization treatment (IVF) but no fresh embryo transfer Queen Mary Hospital, University Hong Kong. organoids derived from fragments. established digested into single droplet-based single-cell sequencing investigate cellular population component. Participants/materials, setting, methods filtered high-quality analysis data clustered assigned types according expressions classical markers. Potential cluster was identified by trajectory analysis, RNA velocity, CytoTRACE literature search. existence validated immunofluorescence staining flow cytometric tissues/endometrial clonogenicity isolated eeSCs determined clonogenic assay. Main results role chance exhibit morphology marker expression pattern glands. They also expanded long-term resemblance between generated further supported RNA-seq analysis. Seurat clustering identifies 8 clusters velocity revealed potential at starting point differentiation immature toward most mature one. Besides, had relatively high stem-cell including Tumor-Associated Calcium Signal Transducer (TACSTD2) Aldehyde Dehydrogenase 1 Family Member A3 (ALDH1A3). Five genes Intercellular Adhesion Molecule (ICAM1), L1 Cell (L1CAM), Annexin A2 (ANXA2), Mesothelin (MSLN), Integrin Subunit Alpha 3 (IGTA3) subsequently cluster. Further immunostaining demonstrated CD54 ANXA2 ∼1% ∼30% whole suspensions, respectively. tissue endometrium. Limitations, reasons caution With basal out/apical phenotype, not exactly similar endometrium vivo, hampering exploration surface interaction experiments. Like systems, it inevitable have heterogeneity inconsistency expansion biological performance. Wider implications findings Gene manipulation technology like CRISPR-Cas9 could utilized genetically alter eeSc construction biobank will offer an opportunity personalized regenerative medicine diagnosis, preventive intervention, approaches gynecological diseases. Trial registration number Not applicableNot applicable