The Identification of Mouse Sperm-Surface-Associated Proteins and Characterization of Their Ability to Act as Decapacitation Factors 1 (original) (raw)
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The epididymis and its role on sperm quality and male fertility
The epididymis is a complex organ where spermatozoa acquire motility and ability to fertilize the egg. Epididymal maturation lasts 1 or 2 weeks and exposes the immature spermatozoa to a sequentially modified milieu, promoting intense interactions with secretions by the epididymal epithelium. Sperm surface modifications in response to interactions with epididymal secretions are key steps to achieve fertility ability. However, the precise molecular mechanisms that convert an immotile and infertile gamete into a highly motile cell capable of fusion with an oocyte are still unknown. Recent data on proteomics and transcriptomics of epididymal fluid and epididymosomes brought new ideas of the physiological roles of proteins and miRNAs in epididymal maturation in spermatozoa. This review focuses on the recent discoveries on epididymal fluid composition and its role on sperm maturation and preservation, linking to their survival and fertility potential.
Function of human epididymal proteins in sperm maturation
Andrologia, 2009
The epididymis is necessary for post-testicular sperm maturation as it provides the milieu required for spermatozoa to gain the ability for progressive movement and fertilization. In the epididymis the sperm protein, lipid and small RNA content are heavily modified due to interaction with luminal proteins secreted by the epididymal epithelium and extracellular vesicles, epididymosomes. This review focuses on epididymal proteins demonstrated to have an effect on sperm functions, such as motility, capacitation, acrosome reaction, sperm-zona pellucida binding and sperm-egg binding, as well as on embryonic development.
Signalling pathways involved in sperm capacitation
2007
After ejaculation, mammalian sperm have not yet acquired full fertilising capacity. They will require a finite period of residence in the female reproductive tract before they become fertilisation competent. The molecular, biochemical, and physiological changes that occur to sperm while in the female tract are collectively referred to as capacitation. During capacitation, changes in membrane properties, enzyme activities, and motility render spermatozoa responsive to stimuli that induce the acrosome reaction and prepare spermatozoa for penetration of the egg investments prior to fertilisation. These changes are facilitated by the activation of cell signalling cascades in the female reproductive tract in vivo or in defined media in vitro. The purposes of this review are to consider some recent contributions towards our understanding of capacitation, to summarise open questions in this field, and to discuss future avenues of research.
Biology of Reproduction, 1996
During epididymal transit, spermatozoa acquire new surface antigens that are involved in the acquisition of their fertilizing ability. We have previously described a 34-kDa (P34H) human epididymal sperm protein that shows antigenic and functional homologies with the hamster P26h. P34H is localized on the acrosomal cap of human spermatozoa and has been proposed to be involved in the interaction with the zona pellucida. The aim of this study was to document the expression of P34H on the sperm surface during transit along the male and female genital tracts. Immunohistochemical techniques were performed on human testes and epididymides by means of an antiserum specific for P34H. No labeling was detected on those spermatozoa found within the seminiferous tubules or in the vasa efferentia. P34H first appeared in the caput epididymidis and was restricted to the acrosomal cap. Signal intensity then increased considerably from the proximal corpus to the cauda region of the epididymis. After ejaculation, the same pattern of P34H distribution was observed, but the intensity was much lower than that characterizing the cauda epididymal spermatozoa. Strong labeling was restored after incubation in B2 medium and was maximal after 5 h of capacitation. After acrosomal exocytosis induced by a Ca 2+ ionophore, the percentage of P34Hlabeled spermatozoa decreased proportionally to the number of acrosome-reacted spermatozoa as determined by Pisum sativum-fluorescein isothiocyanate (FITC) labeling. P34H appeared to be strongly anchored to the sperm plasma membrane during epididymal transit as indicated by the requirement for detergent to extract this surface antigen from ejaculated spermatozoa. This confirms the importance of P34H binding to the sperm plasma membrane during epididymal maturation. We have previously proposed that P34H is involved in sperm-zona pellucida interaction. The appearance and accumulation of P34H on the sperm plasma membrane during epididymal maturation, followed by its inaccessibility associated with ejaculation, its unmasking during capacitation, and finally its elimination after the acrosome reaction, are in agreement with the proposed function of this sperm antigen.
Human epididymal proteins and sperm function during fertilization: un update
Biological Research, 2001
utilized as a new marker for semen abnormalities. In a recent report (Sutovsky et al, 2001b), a "sperm-ubiquitin tag immunoassay (SUTI)" was described as a valuable new tool for infertility diagnosis and prediction of IVF success in subfertile men diagnosed with idiopathic infertility. CONCLUSIONS This review has briefly shown some findings reported by several investigators on a set of human epididymal proteins identified and partially characterized in the recent years. The results suggest that the epididymis produces and secretes numerous proteins that would associate to the spermatozoa while they are transiting through the organ. These components would dramatically affect sperm functionality, allowing the male gamete to recognize the oocyte. However, much still is waiting to be done to comprehend this phenomenon. Implementation of genomics and proteomics will help, in the near future, to further characterize some already identified proteins, as well as to describe novel epididymal components, anticipating great advances in the elucidation of the sperm maturation process in humans.
Spermatozoa with Capacitation and
2015
The objective of this study was to determine the localization and distribution of oocyte plasma membrane binding sites on capacitated and acrosome-reacting live boar spermatozoa. Localization of oocyte plasma membrane binding sites on boar spermatozoa was determined with fluorescence microscopy and population distribution was examined with flow cytometry. The number of spermatozoa with oocyte plasma membrane bound to the equatorial segment and postacrosomal region of the sperm head significantly increased with capacitation. Equatorial segment labelling further increased with induced acrosome reactions. When the population distribution of oocyte plasma membrane binding sites on live boar spermatozoa was analysed, the percentage of spermatozoa with bound oocyte plasma membrane significantly increased after capacitation compared with that of washed spermatozoa. Binding of oocyte plasma membrane did not increase in control spermatozoa incubated under non-capacitating conditions and was not correlated with the percentage of dead spermatozoa. A change in localization of oocyte plasma membrane binding sites on the sperm head was demonstrated using fluorescence microscopy and an increase in oocyte plasma membrane binding sites after capacitation was shown using flow cytometry.