In birds, oviductal cells play a crucial role in the storage of sperm via cell-to-cell communication including extracellular vesicles (EV). We developed a culture of oviductal organoids enriched in sperm storage tubules (SSTorg) to demonstrate the release of EV. SSTorg were cultured for 24 h and added to live (LV), frozen (FZ) and lysed (LY) avian sperm, seminal plasma (SP), avian sperm conditioned medium (CM), or bovine sperm (BV). Western blot demonstrated that SSTorg contained EV protein markers, valosin-containing protein (VCP), heat shock proteins (HSP90AA1, HSPA8), and annexins (ANXA2, A4, A5). Co-culture with LV significantly decreased the intracellular level of all these proteins except HSPA8. Immunohistochemistry confirmed this result for VCP and ANXA4. LY, CM, SP and BV had no effect on the intracellular level of these proteins, whereas FZ induced a decrease in ANXA2, A4 and A5. In culture media, VCP and HSP90AA1 signals were detected in the presence of LV, FZ, BV, LY, CM and SP, but no ANXA4 signal was observed in the presence of FZ and SP. ANXA2 and A5 were only detected in the presence of LV. The most abundant EV were less than 150 nm in diameter. ANXA4 and A5 were more abundant in EV isolated from the SSTorg culture medium. This study provides a useful culture system for studying interactions between SST cells and sperm. We demonstrated the release of EV by SSTorg in vitro, and its regulation by sperm. This may be of crucial importance for sperm during storage in hens.
Luiz Cordeiro, Cindy Riou, Rustem Uzbekov, and Nadine Gérard
Julie Lamy, Emilie Corbin, Marie-Claire Blache, Anastasiia S Garanina, Rustem Uzbekov, Pascal Mermillod, and Marie Saint-Dizier
After insemination in the cow, a sperm reservoir is formed within the oviducts, allowing the storage and then progressive release of spermatozoa toward the ovulated oocyte. In order to investigate the hormonal regulation of these events in vitro, the ovarian steroids 17β-estradiol (E2) and progesterone (P4) were added at various concentrations to monolayers of bovine oviduct epithelial cells (BOEC) before or during co-incubation with spermatozoa. Main findings demonstrate that (1) a 18-h pretreatment of BOEC with 100 pg/mL and 100 ng/mL of E2 decreased by 25% the ability of BOEC to bind spermatozoa after 10 min, and for the highest dose of E2, 60 min of co-incubation; (2) P4 at concentrations of 10, 100 and 1000 ng/mL induced the release within 60 min of 32–47% of bound spermatozoa from BOEC; this sperm-releasing effect was maintained after a 18-h pretreatment of BOEC with 100 pg/mL of E2; (3) E2 in concentrations above 100 pg/mL inhibited the releasing effect of P4 on bound sperm in a dose-dependent manner; (4) spermatozoa bound to BOEC, then released from BOEC by the action of P4-induced higher cleavage and blastocyst rates after in vitro fertilization than the control group. These results support the hypothesis that the dynamic changes in steroid hormones around the time of ovulation regulate the formation of the sperm reservoir and the timed delivery of capacitated spermatozoa to the site of fertilization.
Luiz Cordeiro, Hsiu-Lien Herbie Lin, Anaïs Vitorino Carvalho, Isabelle Grasseau, Rustem Uzbekov, and Elisabeth Blesbois
Male subfertility causes are very varied and sometimes related to post-gonadic maturation disruption, involving seminal plasma constituents. Among them, extracellular vesicles are involved in key exchanges with sperm in mammals. However, in birds, the existence of seminal extracellular vesicles is still debated. The aim of the present work was first to clarify the putative presence of extracellular vesicles in the seminal plasma of chickens, secondly to characterize their size and protein markers in animals showing different fertility, and finally to make preliminary evaluations of their interactions with sperm. We successfully isolated extracellular vesicles from seminal plasma of males showing the highest differences in semen quality and fertility by using ultracentrifugation protocol (pool of 3 ejaculates/rooster, n =3/condition). Size characterization performed by electron microscopy revealed a high proportion of small extracellular vesicles (probably exosomes) in chicken seminal plasma. Smaller extracellular vesicles appeared more abundant in fertile than in subfertile roosters, with a mean diameter of 65.12 and 77.18 nm, respectively. Different protein markers of extracellular vesicles were found by western blotting (n = 6/condition). Among them, HSP90A was significantly more abundant in fertile than in subfertile males. In co-incubation experiments (n = 3/condition), extracellular vesicles enriched seminal fractions of fertile males showed a higher capacity to be incorporated into fertile than into subfertile sperm. Sperm viability and motility were impacted by the presence of extracellular vesicles from fertile males. In conclusion, we successfully demonstrated the presence of extracellular vesicles in chicken seminal plasma, with differential size, protein markers and putative incorporation capacity according to male fertility status.
Carmen Almiñana, Emilie Corbin, Guillaume Tsikis, Agostinho S Alcântara-Neto, Valérie Labas, Karine Reynaud, Laurent Galio, Rustem Uzbekov, Anastasiia S Garanina, Xavier Druart, and Pascal Mermillod
Successful pregnancy requires an appropriate communication between the mother and the embryo. Recently, exosomes and microvesicles, both membrane-bound extracellular vesicles (EVs) present in the oviduct fluid have been proposed as key modulators of this unique cross-talk. However, little is known about their content and their role during oviduct-embryo dialog. Given the known differences in secretions by in vivo and in vitro oviduct epithelial cells (OEC), we aimed at deciphering the oviduct EVs protein content from both sources. Moreover, we analyzed their functional effect on embryo development. Our study demonstrated for the first time the substantial differences between in vivo and in vitro oviduct EVs secretion/content. Mass spectrometry analysis identified 319 proteins in EVs, from which 186 were differentially expressed when in vivo and in vitro EVs were compared (P < 0.01). Interestingly, 97 were exclusively expressed in in vivo EVs, 47 were present only in in vitro and 175 were common. Functional analysis revealed key proteins involved in sperm–oocyte binding, fertilization and embryo development, some of them lacking in in vitro EVs. Moreover, we showed that in vitro-produced embryos were able to internalize in vivo EVs during culture with a functional effect in the embryo development. In vivo EVs increased blastocyst rate, extended embryo survival over time and improved embryo quality. Our study provides the first characterization of oviduct EVs, increasing our understanding of the role of oviduct EVs as modulators of gamete/embryo–oviduct interactions. Moreover, our results point them as promising tools to improve embryo development and survival under in vitro conditions.