Ach1 Build Fertility Centre; 2CReATE Fertility Centre, Division of Obstetrics and Gynaecology, Department of Physiology, Institute of Medical Sciences, University of Toronto, Department of Gynecology, Women’s College HospitalPF08.Embryo-endometrium cross-talk: characterisation of extracellular vesicles from in vitro cultured human embryos Giacomini Elisa1, Riccardo Vago2, Ana Maria Sanchez1, Paola Podini3, Natasa Zarovni4, Valentina Murdica2, Roberta Rizzo5, Daria Bortolotti5, Jennifer Ovalle1 and Paola Vigan Reproductive Serpin B6 Proteins supplier Sciences Laboratory, Division of Genetics and Cell Biology, IRCCS San Raffaele Hospital, Milano, Italy; 2Urological Research Institute, IRCCS San Raffaele Hospital, Milano, Italy; 3Department of Neuroscience, Institute of Experimental Neurology, IRCCS San Raffaele Hospital, Milano, Italy; 4Exosomics Siena SpA; 5Department of Healthcare Sciences, Section of MicroENPP-5 Proteins Molecular Weight Biology and Healthcare Genetics, University of Ferrara, ItalyIntroduction: Productive embryo implantation and consequent pregnancy is critically dependent on a two-way communication amongst the maternal uterus plus the blastocyst. Having said that, offered the ethical restrictions as well as the lack of mechanistic research, the identification of key embryonic signals remains so far elusive. You will discover plenty proof on that extracellular vesicles (EVs) shuttled biomolecules can profoundly affect the phenotype and activity of their target cell and proofs of EV secretion have been reported in most cell sorts like embryonic stem cells and in vitro made embryos derived from some mammalian species. Techniques: We collectedspent medium from embryo culture at day 3 and day 5 after fertilisation, upon ethical committee approval and informed consent. EVs were isolated and characterised by nanoparticle tracking evaluation and transmission electron microscopy. The presence of precise EVs proteins and RNAs have been investigated by western blot and RT-PCR. The uptake of EVs derived from embryos and labelled having a fluorescent dye by primary endometrial cell was monitored by immunofluorescence. Benefits: Conditioned media from non-manipulated human embryos cultured in vitro for 3 days or up to the blastocyst stage contain EVs with a diameter of 3000 nm and show traditional EV marker proteins CD63, CD9 and Alix. The embryonic origin of those EVs was confirmed by the presence of stemness gene transcripts (NANOG and POU5F1) and their enrichment within the non-classical HLA-G protein at suitable stages of development, accordingly to their relative pattern in blastocysts. We also show the preferential uptake of dye-labelled embryo-derived EVs by major endometrial cells. Conclusion: Summary/conclusion: Our findings suggest EV exchange as an emerging way of communication at the maternal oetal interface and raise some thrilling possibilities relating to their potential therapeutic use as a co-factor for promoting the establishment of a thriving pregnancy. Funding: The project was funded by Merck Serono Grant For Innovation.Introduction: The ovarian follicle could be the basic female reproductive unit containing the oocyte, somatic cells and follicular fluid (FF). Suitable intercellular signalling involving these compartments is required for optimal folliculogenesis, ovulation, and hormonal secretion. Current studies have explored human FF exosomes, also called folliculosomes (FFEs). FFE miRNAs have already been implicated as possible biomarkers for Polycystic Ovarian Syndrome (PCOS), blastocyst development, and pregna.