Leukocytospermia and sperm preparation - a flow cytometric study

Background  

Leukocytes represent the predominant source of reactive oxygen species both in seminal plasma and in sperm suspensions and have been demonstrated to negatively influence sperm function and fertilization rate in assisted reproduction procedures. Peroxidase test is the standard method recommended by WHO to detect semen leukocytes but it may be inaccurate. The aims of this study were (i) to compare the efficiency of swim-up and density-gradient centrifugation techniques in removing seminal leukocytes, (ii) to examine the effect of leukocytes on sperm preparation, and (iii) to compare flow cytometry and peroxidase test in determining leukocyte concentration in semen using a multiparameter flow cytometric method.     

Identification of latexin by a proteomic analysis in rat normal articular cartilage

Background  

Osteoarthritis (OA) is characterized by degeneration of articular cartilage. Animal models of OA induced are a widely used tool in the study of the pathogenesis of disease. Several proteomic techniques for selective extraction of proteins have provided protein profiles of chondrocytes and secretory patterns in normal and osteoarthritic cartilage, including the discovery of new and promising biomarkers. In this proteomic analysis to study several proteins from rat normal articular cartilage, two-dimensional electrophoresis and mass spectrometry (MS) were used. Interestingly, latexin (LXN) was found. Using an immunohistochemical technique, it was possible to determine its localization within the chondrocytes from normal and osteoarthritic articular cartilage.     

Alpha6beta1 integrin expressed by sperm is determinant in mouse fertilization

Background  

Based on inhibition tests, the alpha6beta1 integrin was suggested to be a sperm receptor, but further experiments using gene deletion techniques have shown that neither oocyte alpha6, nor beta1 integrin subunits were essential for mouse fertilization.     

Detection of co-eluted peptides using database search methods

Background  

Current experimental techniques, especially those applying liquid chromatography mass spectrometry, have made high-throughput proteomic studies possible. The increase in throughput however also raises concerns on the accuracy of identification or quantification. Most experimental procedures select in a given MS scan only a few relatively most intense parent ions, each to be fragmented (MS²) separately, and most other minor co-eluted peptides that have similar chromatographic retention times are ignored and their information lost.     

Experimental evolution of sperm competitiveness in a mammal

Background  

When females mate with multiple partners, sperm from rival males compete to fertilise the ova. Studies of experimental evolution have proven the selective action of sperm competition on male reproductive traits. However, while reproductive traits may evolve in response to sperm competition, this does not necessarily provide evidence that sperm competitive ability responds to selection. Indeed, a study of Drosophila failed to observe divergence in sperm competitive ability of males in lines selected for enhanced sperm offence and defence.     

iTRAQ-based analysis of sperm proteome from normozoospermic men achieving the rescue-ICSI pregnancy after the IVF failure

Background

In the assisted reproduction, the infertile molecules of spermatozoa from normozoospermic men who underwent the unexplained failure of in vitro fertilization (IVF) due to the lack of sperm binding to the normal zona pellucida, and then achieved pregnancy with the rescue intracytoplasmic sperm injection (R-ICSI) remain unclear. More works are still necessary to explore this male infertile mechanism.

Methods

Normozoospermicmen with the IVF pregnancy and normozoospermic men with the R-ICSI pregnancy after the conventional IVF failure were collected. iTRAQ-based proteomic approach were performed to reveal the new infertile causes between the IVF pregnancy men and the R-ICSI pregnancy men. To validate the confidence of proteome data, the individual samples were analyzed by western blot and immunofluorescence. Further, the spontaneous acrosome reactions were measured to evaluate the sperm quality.

Results

Compared with IVF pregnancy group, 56 sperm proteins were differentially expressed in the R-ICSI pregnancy group. Bioinformatic analyses (PANTHER, DAVID, PubMed and STRING) indicated these altered sperm proteins were involved in various molecular functions: reproduction, chromosome organization, and sperm-oocyte interaction. Moreover, the confidence of proteome data was confirmed by western blot and immunofluorescence using the individual samples, which were consistent with our proteomic data. Additionally, an increased rate of the spontaneous acrosome reaction rate was found in the R-ICSI pregnancy group.

Conclusions

The sealtered sperm proteins and the increased spontaneous acrosome reaction rate might account for this unexplained male infertility in the R-ICSI pregnancy patients. The present proteomic results will throw light on the better understanding of the unexplained infertile mechanisms underlying these normozoospermic man who achieved R-ICSI pregnancy after IVF failure.

     

Sperm DNA fragmentation and oxidation are independent of malondialdheyde

Background  

There is clinical evidence to show that sperm DNA damage could be a marker of sperm quality and extensive data exist on the relationship between DNA damage and male fertility status. Detecting such damage in sperm could provide new elements besides semen parameters in diagnosing male infertility. We aimed to assess sperm DNA fragmentation and oxidation and to study the association between these two markers, routine semen parameters and malondialdehyde formation.     

Deficiency in mouse Y chromosome long arm gene complement is associated with sperm DNA damage

Background  

Mice with severe non-PAR Y chromosome long arm (NPYq) deficiencies are infertile in vivo and in vitro. We have previously shown that sperm from these males, although having grossly malformed heads, were able to fertilize oocytes via intracytoplasmic sperm injection (ICSI) and yield live offspring. However, in continuing ICSI trials we noted a reduced efficiency when cryopreserved sperm were used and with epididymal sperm as compared to testicular sperm. In the present study we tested if NPYq deficiency is associated with sperm DNA damage - a known cause of poor ICSI success.     

Large-scale and high-confidence proteomic analysis of human seminal plasma

Background  

The development of mass spectrometric (MS) techniques now allows the investigation of very complex protein mixtures ranging from subcellular structures to tissues. Body fluids are also popular targets of proteomic analysis because of their potential for biomarker discovery. Seminal plasma has not yet received much attention from the proteomics community but its characterization could provide a future reference for virtually all studies involving human sperm. The fluid is essential for the survival of spermatozoa and their successful journey through the female reproductive tract.     

Reduced levels of intracellular calcium releasing in spermatozoa from asthenozoospermic patients

Background  

Asthenozoospermia is one of the most common findings present in infertile males characterized by reduced or absent sperm motility, but its aetiology remains unknown in most cases. In addition, calcium is one of the most important ions regulating sperm motility. In this study we have investigated the progesterone-evoked intracellular calcium signal in ejaculated spermatozoa from men with normospermia or asthenozoospermia.     

An improved machine learning protocol for the identification of correct Sequest search results

Background  

Mass spectrometry has become a standard method by which the proteomic profile of cell or tissue samples is characterized. To fully take advantage of tandem mass spectrometry (MS/MS) techniques in large scale protein characterization studies robust and consistent data analysis procedures are crucial. In this work we present a machine learning based protocol for the identification of correct peptide-spectrum matches from Sequest database search results, improving on previously published protocols.     

A new picture of cell wall protein dynamics in elongating cells of <Emphasis Type="Italic">Arabidopsis thaliana</Emphasis>: Confirmed actors and newcomers

Background  

Cell elongation in plants requires addition and re-arrangements of cell wall components. Even if some protein families have been shown to play roles in these events, a global picture of proteins present in cell walls of elongating cells is still missing. A proteomic study was performed on etiolated hypocotyls of Arabidopsis used as model of cells undergoing elongation followed by growth arrest within a short time.     

Assessment of sperm quality traits in relation to fertility in boar semen

Background  

Several studies have been published where sperm plasma membrane integrity correlated to fertility. In this study we describe a simple fluorometer-based assay where we monitored the fluorescence intensity of artificially membrane-ruptured spermatozoa with a fixed time staining with fluorescent DNA dyes.     

Feature selection and nearest centroid classification for protein mass spectrometry

Background  

The use of mass spectrometry as a proteomics tool is poised to revolutionize early disease diagnosis and biomarker identification. Unfortunately, before standard supervised classification algorithms can be employed, the "curse of dimensionality" needs to be solved. Due to the sheer amount of information contained within the mass spectra, most standard machine learning techniques cannot be directly applied. Instead, feature selection techniques are used to first reduce the dimensionality of the input space and thus enable the subsequent use of classification algorithms. This paper examines feature selection techniques for proteomic mass spectrometry.     

Delta opioid receptor on equine sperm cells: subcellular localization and involvement in sperm motility analyzed by computer assisted sperm analyzer (CASA)

Background  

Opioid receptors and endogenous opioid peptides act not only in the control of nociceptive pathways, indeed several reports demonstrate the effects of opiates on sperm cell motility and morphology suggesting the importance of these receptors in the modulation of reproduction in mammals. In this study we investigated the expression of delta opioid receptors on equine spermatozoa by western blot/indirect immunofluorescence and its relationship with sperm cell physiology.     

Genes2Networks: connecting lists of gene symbols using mammalian protein interactions databases

Background  

In recent years, mammalian protein-protein interaction network databases have been developed. The interactions in these databases are either extracted manually from low-throughput experimental biomedical research literature, extracted automatically from literature using techniques such as natural language processing (NLP), generated experimentally using high-throughput methods such as yeast-2-hybrid screens, or interactions are predicted using an assortment of computational approaches. Genes or proteins identified as significantly changing in proteomic experiments, or identified as susceptibility disease genes in genomic studies, can be placed in the context of protein interaction networks in order to assign these genes and proteins to pathways and protein complexes.     

Downregulation of both gene expression and activity of Hsp27 improved maturation of mouse oocyte in vitro

Background  

Heat shock protein 27 (Hsp27), a member of the small heat shock protein family, is an apoptosis regulator. Our previous proteomic study showed that Hsp27 mainly expressed in human oocyte, and that Hsp27 expression was downregulated in the ovaries derived from women with the polycystic ovary syndrome (PCOS), a well known endocrinal disorder with abnormal apoptotic activity and folliculogenesis. However, the exact effects of Hsp27 downregulation on oocyte development have not yet been clarified.     

Molecular and functional characterization of voltage-gated sodium channels in human sperm

Background  

We have investigated the expression of voltage-gated sodium channels in human spermatozoa and characterized their role in sperm motility.     

Spatiotemporal association of DNAJB13 with the annulus during mouse sperm flagellum development

Background  

The sperm annulus is a septin-based fibrous ring structure connecting the midpiece and the principal piece of the mammalian sperm flagellum. Although ultrastructural abnormalities and functional importance of the annulus have been addressed in Sept4-null mutant mice and a subset of human patients with asthenospermia syndrome, little is known about how the structure is assembled and positioned to the midpiece-principal piece junction during mammalian sperm flagellum development.