Stallion Epididymal Fluid Proteome: Qualitative and Quantitative Characterization; Secretion and Dynamic Changes of Major Proteins1

Abstract

Proteins present in and secreted into the lumen of various regions of the stallion epididymis were characterized qualitatively and quantitatively by two-dimensional electrophoresis. Using this proteomic approach, 201 proteins were found in the lumen and 117 were found that were secreted by the epithelium in various parts of the organ. Eighteen proteins made up 92.6% of the total epididymal secretory activity, lactoferrin (41.2%) and clusterin (24.8%) being the most abundant. Procathepsin D, HE1/CTP (cholesterol transfer protein), GPX (glutathione peroxidase), beta-N-acetyl-hexosaminidase, and PGDS (prostaglandin D2 synthase) were the other major compounds secreted. The most abundant proteins found in the luminal fluid were albumin and the secreted proteins: lactoferrin, PGDS, GPX, HE1/CTP, and hexosaminidase. Three main secretory epididymal regions were identified from the protein pattern, i.e., regions E0-E2, E3-E5, and E6-E9. Region E0-E2 was characterized by the secretion of clusterin (53%), PGDS (44%), and GPX (6%). Region E3-E5 had the highest number of secreted proteins, the highest protein concentrations (60-80 mg/ml), and the highest spermatocrit value (85%). Lactoferrin (60% in E4), clusterin (29% in E3), hexosaminidase (10% in E3), and procathepsin D (6.9% in E4) were the most abundant proteins in this region. Region E6-E9, in which few region-specific secreted compounds were found, was characterized by a high quantity of lactoferrin in the luminal fluid (2-14 mg/ml). Comparison between the secretion of the major proteins and their concentrations in the lumen throughout the organ showed that the behavior of each protein is specific, in particular for the three isoforms of clusterin.

Seminal Plasma Proteins as Potential Markers of Relative Fertility in Boars

“…The analysis of seminal plasma proteins using proteomics techniques provides important preliminary data on the abundance of specific proteins in seminal plasma without having to rely on existing antibodies for detection (Fouchécourt et al, 2000;Moura et al, 2007;Martínez-Heredia et al, 2008). This approach has also been successfully used to identify proteins that were associated with fertility in the stallion (Brandon et al, 1999), and the bull (Killian et al, 1993).…”

“…Specific proteins in seminal plasma have been identified as potential markers of male fertility or infertility in the human (Yamakawa et al, 2007;Martínez-Heredia et al, 2008). Comprehensive proteomic analyses have been conducted in the bull (Moura et al, 2007) and stallion (Fouchécourt et al, 2000) to identify proteins in the male accessory gland fluids. In the pig, initial characterization of proteins in boar seminal plasma has begun (Strzezek et al, 2005); however, to date, no seminal plasma proteins identified in boar seminal plasma have been associated with fertility in vivo.…”

Sperm surface changes and physiological consequences induced by sperm handling and storage

“…The sperm surface is then further modified in the epididymis by sequential exposure to a highly dynamic protein environment created by regionalised secretion and absorption of proteins across the epididymal epithelium. The varying complement of molecules found in the specialised regions of the epididymal tract has been described in numerous species (pig (Dacheux et al 1989, Syntin et al 1996, Guyonnet et al 2009), bull (Belleannee et al 2011, stallion (Fouchecourt et al 2000), rat (Vreeburg et al 1992, Suryawanshi et al 2011 and human (Baker et al 2005, Li et al 2010) including details of all the proteins present (proteome), secreted (secretome) or transcribed (transcriptome), and this information has greatly expanded knowledge of the role of epididymal proteins in sperm maturation (reviewed by Gatti et al (2004) and Dacheux et al (2005Dacheux et al ( , 2009). …”

Spermatogenic and sperm quality differences in an experimental model of metabolic syndrome and hypogonadal hypogonadism

“…Associated with decreased embryo quality and lower implantation rates (Morris et al 2002, Henkel et al 2003, sperm nDNA damage is currently thought to result from the attack by reactive oxygen species (ROS) encountered in the testis and during transit through, and storage in, the epididymis (Fouchecourt et al 2000, Vernet et al 2004). The precise mechanism that investigates the oxidative stress that causes the generation of ROS and subsequently leads to sperm DNA damage remains unknown.…”