UTEROSOME-LIKE VESICLES PROMPT HUMAN SPERM FERTILIZING CAPACITY

CUBILLA, M.A.; GIOJALAS, L.C.; FRANCHI, N.A.; BRAVO, A.A.; GUIDOBALDI, H.A.

Córdoba

Congreso; LII Reunión Anual Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2016

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular

It is known that the uterine environment affects sperm function, but the underlying cellular mechanisms still remain unknown. Extracellular vesicles have been recently identified along the female reproductive tract, including the uterus, where they were called uterosomes. Previous data showed that conditioned medium from endometrial cells stimulate sperm capacitation. Thus, we hypothesize that extracellular vesicles may be mediating this sperm fertilizing capacity induction. In this study, we characterized uterosome-like vesicles (ULV) obtained from the conditioned medium of an endometrial epithelial cell line, and analyzed their interaction with human spermatozoa. We found that the isolated ULV were ~50-200 nm in size, with characteristic cup-shape morphology. In addition, the ULV were positive for CD63 and MFGE8 protein markers, as shown by Western blot and immunogold labelling. Furthermore, after only 15 minutes of in vitro co-incubation, ULV seem to be able to fuse with spermatozoa stimulating capacitation, as determined by the induced acrosome reaction and the protein tyrosine phosphorylation. The present results suggest that the brief transit of human spermatozoa through the uterine environment might be enough to enhance sperm fertilizing capacity through a novel extracellular vesicles mediated mechanism.