Protein profile of capacitated versus ejaculated human sperm.

Freshly ejaculated sperm acquire the fertilizing potential by a continuing process that occurs during sperm transport through the female genital tract, and it is physiologically not complete until the spermatozoon reaches the oocyte. The process termed capacitation can be mimicked in vitro by using appropriate capacitation media. Despite its importance, the molecular mechanisms underlying capacitation are poorly understood. This work deals with a proteomic approach to the analysis of protein profile variations in human normospermic samples as a consequence of three hours in vitro capacitation. 2DE gels were produced per freshly ejaculated sperm and per capacitated sperm and several quantitative and qualitative significant variations were found. Among the MS obtained identifications, proteins with a significant decrease after capacitation were found to be involved in protein fate, metabolism, and flagellar organization; on the contrary, increasing proteins were found to be related to cellular stress. Interestingly, the detected flagellar organization proteins decreased during capacitation whereas their corresponding fragments increased. A swim-up selected and three-hour capacitated sperm subpopulation has also been resolved by 2DE, and its synthetic gel has been analyzed for the variations observed in the entire sperm population. An immunofluorescence analysis of this sperm typology was carried out with antiactin and antitubulin antibodies.

Menstrual cycle-related sialidase activity of the female cervical mucus is associated with exosome-like vesicles.

OBJECTIVE: To study endogenous sialidase activity in genital tract secretions of pregnant and nonpregnant women. DESIGN: Laboratory study. SETTING: Department of Evolutionary Biology and Department of Obstetrics and Reproductive Medicine, University of Siena, Siena, Italy. INTERVENTION(S): Vaginal and cervical mucus samples were obtained from pregnant and nonpregnant women in different phases of the menstrual cycle and in different weeks of pregnancy. MAIN OUTCOME MEASURE(S): Sialidase activity was assessed by fluorimetric assay and localized by transmission electron microscopy and differential centrifugation. RESULT(S): Sialidase activity in cervical mucus of healthy women reaches a maximum in the ovulatory phase. Cervical mucus from pregnant and nonpregnant women had significant sialidase activity that was associated with membranous vesicles having an exosome-like structure. CONCLUSION(S): Female cervical mucus contains an endogenous menstrual cycle-related sialidase that could be involved in modifying the rheologic properties of mucus to favor sperm progression at fertilization. Its association with exosome-like vesicles also suggests a role in intercellular communication before and after fertilization.