Uterosome-like vesicles prompt human sperm fertilizing capacity.

FRANCHI, A; CUBILLA, MC; GUIDOBALDI, HA; BRAVO, AA; GIOJALAS, LC

Córdoba

Congreso; LII Reunion Anual SAIB; 2016

SAIB

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 calleduterosomes. Previous data showed that conditioned medium from endometrial cells stimulate sperm capacitation. Thus, wehypothesize that extracellular vesicles may be mediating this sperm fertilizing capacity induction. In this study, we characterizeduterosome-like vesicles (ULV) obtained from the conditioned medium of an endometrial epithelial cell line, and analyzed theirinteraction with human spermatozoa. We found that the isolated ULV were ~50-200 nm in size, with characteristic cup-shapemorphology. In addition, the ULV were positive for CD63 and MFGE8 protein markers, as shown by Western blot and immunogoldlabelling. Furthermore, after only 15 minutes of in vitro co-incubation, ULV seem to be able to fuse with spermatozoa stimulatingcapacitation, as determined by the induced acrosome reaction and the protein tyrosine phosphorylation. The present results suggest thatthe brief transit of human spermatozoa through the uterine environment might be enough to enhance sperm fertilizing capacity througha novel extracellular vesicles mediated mechanism.