Lipid changes of goat sperm plasma membrane during epididymal maturation
TL;DR: The altered lipid profile of the mature sperm membrane leads to changes in its fluidity that play an important role in determining the structure and functions of the biomembrane.
About: This article is published in Biochimica et Biophysica Acta.The article was published on 1991-01-30. It has received 76 citations till now. The article focuses on the topics: Sperm plasma membrane & Membrane lipids.
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TL;DR: It is shown that mouse epididymal spermatozoa were distinguished by high percentages of SM and polyunsaturated membranous fatty acids (PUFAs), principally represented by arachidonic, docosapentanoic, and docosahexanoic acids.
Abstract: We have isolated vesicular structures from mouse epididymal fluid, referred to as epididymosomes. Epididymosomes have a roughly spherical aspect and a bilayer membrane, and they are heterogeneous in size and content. They originate from the epididymal epithelium, notably from the caput region, and are emitted in the epididymal lumen by way of apocrine secretion. We characterized their membranous lipid profiles in caput and cauda epididymidal fluid samples and found that epididymosomes were particularly rich in sphingomyelin (SM) and arachidonic acid. The proportion of SM increased markedly during epididymal transit and represented half the total phospholipids in cauda epididymidal epididymosomes. The cholesterol:phospholipid ratio increased from 0.26 in the caput to 0.48 in the cauda epididymidis. Measures of epididymosomal membrane anisotropy revealed that epididymosomes became more rigid during epididymal transit, in agreement with their lipid composition. In addition, we have characterized the membrane lipid pattern of murine epididymal spermatozoa during their maturation. Here, we have shown that mouse epididymal spermatozoa were distinguished by high percentages of SM and polyunsaturated membranous fatty acids (PUFAs), principally represented by arachidonic, docosapentanoic, and docosahexanoic acids. Both SM and PUFA increased throughout the epididymal tract. In particular, we observed a threefold rise in the ratio of docosapentanoic acid. Epididymal spermatozoa had a constant cholesterol:phospholipid ratio (average, 0.30) during epididymal transit. These data suggest that in contrast with epididymosomes, spermatozoal membranes seem to become more fluid during epididymal maturation.
179 citations
TL;DR: This review will focus on epididymal maturation events, with emphasis in recent advances in the understanding of the molecular basis of this process.
Abstract: After leaving the testis, spermatozoa have not yet acquired the ability to move progressively and are unable to fertilize oocytes. To become fertilization competent, they must go through an epididymal maturation process in the male, and capacitation in the female tract. Epididymal maturation can be defined as those changes occurring to spermatozoa in the epididymis that render the spermatozoa the ability to capacitate in the female tract. As part of this process, sperm cells undergo a series of biochemical and physiological changes that require incorporation of new molecules derived from the epididymal epithelium, as well as post-translational modifications of endogenous proteins synthesized during spermiogenesis in the testis. This review will focus on epididymal maturation events, with emphasis in recent advances in the understanding of the molecular basis of this process.
163 citations
Additional excerpts
...…(PS) ↓ ND = ↓ = b ↓ a ↓ a Sphyngomyelin (SM) ↑ ↓ ND ↓ ↑ a,b ND ↑ a Sterols Cholesterol ↓ ↑ ↓ ND ↓ b ↓ a ↓ a Desmosterol ↑ ↓ ↑ ND ND ↓ a ↑ b Membrane fluidity ND ND ↑ ↑ ↑ b ↑ b ↑ a References Nikolopoulou et al. (1985) Rana et al. (1991) Awano et al. (1993, 1989) Haidl & Opper…...
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TL;DR: This review summarizes current knowledge of how the membrane organization of the mammalian spermatozoon is determined by its complex mixture of lipids.
Abstract: The mammalian spermatozoon is a highly polarized cell consisting of two main sections, the head and the tail. These sections are enclosed by a differentiated plasma membrane to give five specialized regions: acrosome (AC), equatorial region (EQ), postacrosome (PA), midpiece (MP) and the principle piece (PP) (Fig. 1) (Bedford & Hoskins, 1990). Each region has a specialized function; its associated membrane has a lipid and protein composition that is tailored to provide a suitable environment for that function (Holt, 1984; Peterson & Russell, 1985). The membrane lipid infrastructure and fluidity develops during maturation to ensure that the genetic material carried by the sperm cell is joined with that of the ovum for fertilization. Mammalian spermatozoa, upon leaving the testis, pass through the epididymis, where they undergo a process of maturation. The sperm transits from the caput to the cauda via the corpus, during which it undergoes various morphological, physiological and biochemical changes (Bedford & Hoskins, 1990). The plasma membrane especially undergoes considerable reorganization to provide the potential for capacitation (Cooper, 1986; Fraser, 1995; Harrison & Gadella, 1995). The process of capacitation prepares the plasma membrane for the acrosome reaction, and is essential if the spermatozoon is to fertilize an egg (Fraser, 1995). The acrosome is a membrane limited vesicle that is located in the anterior head region, between the nuclear envelope and the plasma membrane. It consists of an inner and outer membrane, which in the equatorial region, form a stable parallel arrangement. During the acrosome reaction enzymes are released from this vesicle. The outer acrosomal membane fuses with the overlaying plasma membrane of the anterior head region. The hybrid membrane is shed, before the spermatozoon can penetrate the egg. The inner membrane and the equatorial region of the acrosome remain intact after completion of the reaction (Bedford & Hoskins, 1990). Energy for the cell is provided by mitochondria that are located in the midpiece region. The highest concentration of membranous structures is therefore located in the anterior head (AC) and the midpiece regions. The literature regarding lipid composition and fluidity of mammalian spermatozoan membranes is fragmentary and often species-specific. However, this review summarizes current knowledge of how the membrane organization of the mammalian spermatozoon is determined by its complex mixture of lipids. Where necessary aspects such as the role of the lipids in cryopreservation (Parks & Graham, 1992), peroxidation (Aitken, 1995; Lenzi et al., 1996) and protein regionalization (Cowan & Myles, 1993; Cowan et al., 1997) will be mentioned but have been adequately dealt with by the reviews cited.
120 citations
Cites background from "Lipid changes of goat sperm plasma ..."
...The second major lipid component of sperm membranes is sterol of which cholesterol is the most abundant found in a variety of species (Parks & Lynch, 1992; boar, Nikolopoulos et al., 1985; goat, Rana et al., 1991; rat, Agrawal et al., 1988)....
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...In both ram (Parks & Hammerstedt, 1985) and goat (Rana et al., 1991) the sterol and phospholipid remodeling results in an increase in the sterol-to-phospholipid molar ratio....
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...…spermatozoa decreases markedly and in most species there are specific changes in fatty acids, (bull, Poulos, Voglmayr & White, 1973; boar, Nikolopoulou et al., 1985; ram, Poulos et al., 1975; Hammerstedt et al., 1979; Parks & Hammerstedt, 1985; goat, Rana et al., 1991; rat, Aveldano et al., 1992)....
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..., 1993), goat (Rana et al., 1991), and boar (Nikolopoulou et al....
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...Sphingomyelin from rhesus monkey (Lin et al., 1993), goat (Rana et al., 1991), and boar (Nikolopoulou et al., 1985, 1986; Evans et al., 1980) spermatozoa has a low polyunsaturated fatty acid content....
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TL;DR: Strikerol dynamics in sperm maturation is discussed and recent methodological advances that will help to illuminate the complexity of sperm formation and function are described.
100 citations
TL;DR: The removal of coating proteins, cholesterol efflux, domain organization, relocalization of lipids and proteins and the role of fusogenic lipids during capacitation are discussed.
Abstract: Sperm membranes have an unusual lipidic composition which is distinct from those of mammalian somatic cells. They have high levels of plasmalogens, a kind of ether-linked lipids, and a high content of polyunsaturated fatty acyl groups. Plasmalogens may form non-diffusible membrane regions or domains, whereas polyunsaturated ethanolamine plasmalogens are known to destabilize the lipidic bilayer. During transit of sperm through the female reproductive tract, sperm-coating proteins bind to heparin-like glycosaminoglycans. An essential feature of capacitation is the removal of cholesterol from the acrosomal membrane of sperm. Albumin and high-density lipoproteins present in the uterine and follicular fluid act as cholesterol acceptors. Plasma membrane of sperm organize in large non-diffusible lipid domains. This regionalization affects the distribution of both lipids and proteins. A barrier to lateral diffusion of lipids and proteins in the equatorial segment has been reported and contributes to the formation of macrodomains. Lateral separation into cholesterol-rich and cholesterol-depleted microdomains could also be created. Cone-shaped phospholipids induce the formation of non-bilayer phases and might facilitate membrane fusion. This review will discuss the removal of coating proteins, cholesterol efflux, domain organization, relocalization of lipids and proteins and the role of fusogenic lipids during capacitation.
95 citations
Cites background from "Lipid changes of goat sperm plasma ..."
...One of the important components of the plasma membrane of sperm is sphingomyelin, which shows maximal level of saturated fatty acids (80-97%) in goat and boar sperm (26, 27)....
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...During epididymal maturation, a decrease in the amount of sperm lipid has been reported in the sperm of boar, rat, bull and ram (26-28)....
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References
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Journal Article•
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