Protein synthesis and acrosome reaction-inducing activity of human cumulus cells

Abstract

The acrosome reaction of human spermatozoa is a prerequisite to fertilization. It has been hypothesized that secretions of cumulus cells could be involved in the induction of this sperm reaction. A source of variation in the in-vitro fertilization of human oocytes could be the maturational differences in the cumulus cells which affect the acrosome reaction. In order to investigate this possibility, we have studied the capability of secretions obtained from cumulus cells of different maturational stages to induce the acrosome reaction. Capacitated spermatozoa were exposed to the culture medium containing cumulus cell secretions and their acrosomal status was evaluated using the triple stain technique. The maturational status of the cumulus or fertilization of the enclosed oocyte did not influence the percentage of acrosome-reacted live spermatozoa. In order to further document these observations, cumulus cells were submitted to [35S]methionine incorporation and total and secreted proteins were analysed by SDS-PAGE electrophoresis. Neither quantitative nor qualitative changes were detected in the electrophoretic patterns of the proteins obtained from cumulus cells of different maturational status. Thus, variation of the acrosome reaction-inducing activity of cumulus cells does not appear to be involved in the variable fertilization of oocytes obtained from follicles of differing maturity.

Cumulus Oophorus-associated Glycodelin-C Displaces Sperm-bound Glycodelin-A and -F and Stimulates Spermatozoa-Zona Pellucida Binding

“…Conditioned medium from cumulus cell culture induces acrosome reaction (40) and stimulates sperm motility (41). In this study, the acquisition of glycodelin immunoreactivity after penetration of the cumulus oophorus and Western blot analysis of the cumulus matrix demonstrate the presence of a small glycodelin-like molecule that interacts with the spermatozoa.…”

Cumulus cells and their extracellular matrix affect the quality of the spermatozoa penetrating the cumulus mass

“…Therefore, the cumulus oophorus is at an ideal position to modulate the fertilizing ability of spermatozoa passing through it. Indeed, the cumulus oophorus is known to affect human sperm functions (11)(12)(13)(14)(15)(16)(17)(18) and failure of its formation affects fertilization (8)(9)(10). The present study was designed to differentiate the roles of extracellular matrix and cumulus cells in affecting the functions of spermatozoa traversing the cumulus mass.…”

“…Earlier studies have reported that the cumulus cells affected sperm functions in vitro (11)(12)(13)(14)(15)(16)(17)(18). One report showed that coculture of human spermatozoa with cumulus cells significantly increased the fusion of spermatozoa with zona-free hamster oocyte (12).…”

“…The action of cumulus cells on sperm function may be mediated via the secretory products of the cells (11,13,18,20,21). Thus, spent medium from cumulus cell culture induced acrosome reaction (11) and stimulated sperm motility (13).…”

“…Thus, spent medium from cumulus cell culture induced acrosome reaction (11) and stimulated sperm motility (13). However, the physiologic significance of these observations remain to be demonstrated, because the conditioned medium used in these studies was collected after prolonged cumulus cell culture, which might have affected the normal physiology of the cells.…”