Progesterone induces sperm release from oviductal epithelial cells by modifying sperm proteomics, lipidomics and membrane fluidity. (15th March 2020) - Ramal-Sanchez, Marina
Abstract: The sperm reservoir is formed after insemination in mammals, allowing sperm storage in the oviduct until their release. We previously showed that physiological concentrations of progesterone (P4) trigger in vitro the sperm release from bovine oviductal epithelial cells (BOECs), selecting a subpopulation of spermatozoa with a higher fertilizing competence. Here, by using Western-Blot, confocal microscopy and Intact Cell MALDI-TOF-Mass Spectrometry strategies, we elucidated the changes derived by the P4-induced release on sperm cells (BOEC-P4 spz). Our findings show that, compared to controls, BOEC-P4 spz presented a decrease in the abundance of Binder of Sperm Proteins (BSP) −3 and −5, suggesting one mechanism by which spermatozoa may detach from BOECs, and thus triggering the membrane remodeling with an increase of the sperm membrane fluidity. Furthermore, an interesting number of membrane lipids and proteins were differentially abundant in BOEC-P4 spz compared with controls. Highlights: Spermatozoa released by P4 showed a decreased abundance of Binder of Sperm Proteins (BSP)-3 and −5. Spermatozoa released by P4 from oviductal cells displayed an increased membrane fluidity. P4-induced release from oviductal cells modified the sperm lipidomic and proteomic profiles. A number of interesting proteins and lipids are found as potential sperm fertility biomarkers.