O-189 Extracellular vesicles derived from human myometrial cells support endometrial mesenchymal stromal/stem cells

Abstract Study question Whether other forms of intercellular communication such as extracellular vesicles (EVs) participate in stem cell maintenance the human endometrium. Summary answer The present study revealed involvement EVs a novel method between endometrial mesenchymal cells (eMSC) and their surrounding niche. What is known already In endometrium, many studies have demonstrated importance mediating various physiological well pathological processes. Our group has that myometrial are candidate niche eMSC modulating biological function. We also demonstrate Notch signaling pathway involved regulation. Although classical relies on direct contact dependent interactions, this can be activated at distance by containing ligands. Therefore, we hypothesized certain ligand(s) packaged into to mediate functions. design, size, duration Sequential beading with magnetic beads coated anti-CD140b anti-CD146 antibodies was used isolate (CD140b+CD146+ cells) from tissues proliferative (n = 15) secretory 10) phase. Myometrial derived 17) were isolated ultracentrifugation. characterized transmission electron microscopy western blotting. Participants/materials, setting, methods Endometrial samples obtained women aged 41 – 52 years undergoing total abdominal hysterectomy. EMSC cocultured percentage analysed flow cytometry. Blockage secretion performed transfection Rab27a siRNA. Western blot analysis gene silencing approach validated role eMSC. therapeutic features transplanted eMSC/myometrial determined using mouse injured model. Main results chance released internalized eMSC, leading significant effect stemness Pharmacological inhibition DAPT or 1 nullified these stimulatory effects. contains high amount notch ligand JAG1, thus inducing strong activity When JAG1 silenced EVs, self-renewal clonogenic reduced. Combined transplantation improves regeneration vivo. observed feature potentially achieved elevating proliferation suppressing apoptosis Limitations, reasons for caution activities remains unknown. Also, types i.e. epithelial may regulate Wider implications findings stimulated function via signaling. near future, it would important explore whether plays endometrium EVs. Trial registration number Not applicable