Roles of mouse sperm‐associated alpha‐L‐fucosidases in fertilization

Abstract

Sperm-associated α-L-fucosidases have been implicated in fertilization in many species. Previously, we documented the existence of α-L-fucosidase in mouse cauda epididymal contents, and showed that sperm-associated α-L-fucosidase is cryptically stored within the acrosome and reappears within the sperm equatorial segment after the acrosome reaction. The enrichment of sperm membrane-associated α-L-fucosidase within the equatorial segment of acrosome-reacted cells implicates its roles during fertilization. Here, we document the absence of α-L-fucosidase in mouse oocytes and early embryos, and define roles of sperm associated α-L-fucosidase in fertilization using specific inhibitors and competitors. Mouse sperm were pretreated with deoxyfuconojirimycin (DFJ, an inhibitor of α-L-fucosidase) or with anti-fucosidase antibody; alternatively, mouse oocytes were pretreated with purified human liver α-L-fucosidase. Five-millimolar DFJ did not inhibit sperm-zona pellucida (ZP) binding, membrane binding, or fusion and penetration, but anti-fucosidase antibody and purified human liver α-L-fucosidase significantly decreased the frequency of these events. To evaluate sperm-associated α-L-fucosidase enzyme activity in post-fusion events, DFJ-pretreated sperm were microinjected into oocytes, and 2-pronuclear (2-PN) embryos were treated with 5 mM DFJ with no significant effects, suggesting that α-L-fucosidase enzyme activity does not play a role in post-fusion events and/or early embryo development in mice. The recognition and binding of mouse sperm to the ZP and oolemma involves the glycoprotein structure of α-L-fucosidase, but not its catalytic action. These observations suggest that deficits in fucosidase protein and/or the presence of anti-fucosidase antibody may be responsible for some types of infertility.

Drosophila sperm surface alpha-l-fucosidase interacts with the egg coats through its core fucose residues

“…In addition, during the past 20 years, sperm-associated a-L-fucosidases have been identified in a wide variety of organisms, suggesting that this glycosidase is likely to have a role in gamete interactions. In fact, several studies have provided direct evidence supporting roles for fucose or glycans containing fucose and/or fucosidases in spermeegg binding in a variety of species, including molluscs (Focarelli et al, 1997), ascidians (Hoshi et al, 1983(Hoshi et al, , 1985Matsumoto et al, 2002), amphibians (Martinez et al, 2000), fish (Venditti et al, 2009), mammals (Srivestava et al, 1986;Abascal et al, 1998;Alhadeff et al, 1999;Khunsook et al, 2003;Venditti et al, 2010;Phopin et al, 2013), and flies (Intra et al, , 2009Pasini et al, 2008;Xu et al, 2011). Initially, we purified sperm a-L-fucosidase from D. ananassae, due to the low stability showed by the enzyme in other species .…”

“…In particular, experimental evidence suggest that sperm surface glycosidases could act in a non-catalytic or lectinlike manner, recognizing complementary sugar moieties in the egg envelope (Miranda et al, 2000;Martinez et al, 2000;Perotti et al, 2001;Miller et al, 2002;Intra et al, 2006;Zitta et al, 2006;Hedrick, 2008;Honegger and Koyanagi, 2008;Intra et al, 2011). Examples of glycosidases on the sperm plasma membrane include mannosidases and fucosidases in mammalian sperm (Tulsiani et al, 1989(Tulsiani et al, , 1990Venditti et al, 2010;Phopin et al, 2012Phopin et al, , 2013, fucosidases and N-acetylglucosaminidases in tunicates (Hoshi et al, 1983(Hoshi et al, , 1985(Hoshi et al, , 1994Hoshi, 1986;Godknecht and Honegger, 1991;Matsumoto et al, 2002;Downey and Lambert, 1994), and mannosidases, fucosidases and N-acetylglucosaminidases in flies (Cattaneo et al, 1997(Cattaneo et al, , 2002Pasini et al, 1999;Perotti et al, 2001;Intra et al, 2006Intra et al, , 2009Intra et al, , 2011. In insects, the mechanisms of spermeegg interactions are poorly understood, and spermeegg interactions have been studied in only two Dipteran species.…”

“…Sperm-associated a-L-fucosidases which have been suggested to be potentially involved in fertilization have been found in many species beyond Drosophila, including ascidians (Hoshi et al, 1983(Hoshi et al, , 1994Matsumoto et al, 2002), molluscs, such as Unio elongatulus (Focarelli et al, 1997), toads (Martinez et al, 2000), fish (Venditti et al, 2009), rodents (Hancock et al, 1993;Aviles et al, 1996;Abascal et al, 1998;Venditti et al, 2010;Phopin et al, 2012Phopin et al, , 2013, and mammals, such as bulls (Jauhiainen and Vanhaperttula, 1986), and humans (Alhadeff et al, 1999;Khunsook et al, 2003).…”

Acrosome Reaction as a Preparation for Gamete Fusion

“…In hamster, blocking α-L-fucosidase activity of capacitated spermatozoa does not inhibit ZP binding or penetration, but did inhibit sperm-oocyte membrane interactions and/or some early stages of embryogenesis (Venditti et al 2010). Pretreatment of mouse spermatozoa with anti-fucosidase antibody or exposure of oocytes to purified human liver α-L-fucosidase inhibits sperm-oolemma binding and gamete fusion but not post-fusion events (Phopin et al 2013). Accordingly, addition of L-fucose to the fertilization media results in a significant decrease in the penetration of zona-free eggs in mice (Boldt et al 1989) supporting the involvement of α-L-fucosidase in gamete fusion.…”

Characterization of a Dipeptidyl Peptidase and its Role in Motility of Rat Epididymal Maturing Spermatozoa

“…Sperm surface glycoproteins are thought to play an important role in epididymal sperm maturation process. [2][3][4][5][6] This level of alteration in surface glycoproteins varies from species to species and differs in each epididymal region. 7 Several studies have provided evidence to suggest that the sperm plasma membrane undergoes extensive biochemical changes, including organization and modification of surface glycoprotein, as spermatozoa transit from the proximal to the distal part of the epididymis.…”