Differential proteins associated with plasma membrane in X- and/or Y-chromosome bearing spermatozoa in indicus cattle

Comparative Bioinformatic Analysis of the Proteomes of Rabbit and Human Sex Chromosomes

Studying proteins associated with sex chromosomes can provide insights into sex-specific proteins. Membrane proteins accessible through the cell surface may serve as excellent targets for diagnostic, therapeutic, or even technological purposes, such as sperm sexing technologies. In this context, proteins encoded by sex chromosomes have the potential to become targets for X- or Y-chromosome-bearing spermatozoa. Due to the limited availability of proteomic studies on rabbit spermatozoa and poorly annotated databases for rabbits compared to humans, a bioinformatic analysis of the available rabbit X chromosome proteome (RX), as well as the human X (HX) and Y (HY) chromosomes proteome, was conducted to identify potential targets that could be accessible from the cell surface and predict which of the potential targets identified in humans might also exist in rabbits. We identified 100, 211, and 3 proteins associated with the plasma membrane or cell surface for RX, HX, and HY, respectively, of which 61, 132, and 3 proteins exhibit potential as targets as they were predicted to be accessible from the cell surface. Cross-referencing the potential HX targets with the rabbit proteome revealed an additional 60 proteins with the potential to be RX targets, resulting in a total of 121 potential RX targets. In addition, at least 53 possible common HX and RX targets have been previously identified in human spermatozoa, emphasizing their potential as targets of X-chromosome-bearing spermatozoa. Further proteomic studies on rabbit sperm will be essential to identify and validate the usefulness of these proteins for application in rabbit sperm sorting techniques as targets of X-chromosome-bearing spermatozoa.

Biochemical Features of X or Y Chromosome-Bearing Spermatozoa for Sperm Sexing

This review presents information on biochemical features of spermatozoa bearing X or Y chromosome, enabling production of a sperm fraction with pre-defined sex chromosome. The almost only technology currently used for such separation (called sexing) is based on the fluorescence-activated cell sorting of sperm depending on DNA content. In addition to the applied aspects, this technology made it possible to analyze properties of the isolated populations of spermatozoa bearing X or Y chromosome. In recent years, existence of the differences between these populations at the transcriptome and proteome level have been reported in a number of studies. It is noteworthy that these differences are primarily related to the energy metabolism and flagellar structural proteins. New methods of sperm enrichment with X or Y chromosome cells are based on the differences in motility between the spermatozoa with different sex chromosomes. Sperm sexing is a part of the widespread protocol of artificial insemination of cows with cryopreserved semen, it allows to increase proportion of the offspring with the required sex. In addition, advances in the separation of X and Y spermatozoa may allow this approach to be applied in clinical practice to avoid sex-linked diseases.

Quantitative proteomics profiling of spermatozoa and seminal plasma reveals proteins associated with semen quality in Bos indicus bulls

Cattle breeding approaches are an evolving field of research in veterinary science. Certain factors such as Ejaculate Rejection Rate (ERR) pose a limitation to such approaches. In this regard, we sought to investigate the spermatozoa and seminal plasma proteome of Hallikar bulls with low (n = 3) and high (n = 3) ERR. Through the Tandem mass spectrometry approach, we identified a total of 2409 proteins, in which 828 proteins were common in both the semen components, whereas 375 and 378 proteins were unique to spermatozoa and seminal plasma respectively. Tandem mass tags (TMT) based protein quantification resulted in 75 spermatozoal, and 42 seminal plasma proteins being differentially regulated between high and low ERR bulls. Proteins such as SPADH2, TIMP-2, and PLA2G7 which are negative regulators of motility were upregulated in the seminal plasma of high ERR bulls. Proteins such as OAZ3, GPx4, and GSTM3 whose upregulation leads to reduced motility were upregulated in the spermatozoa of high ERR bulls. Caltrin and ADM proteins that enhance sperm motility were downregulated in the seminal plasma of high ERR bulls. The regulation of ACE, a negative regulator of sperm motility was upregulated in both the spermatozoa and seminal plasma of high ERR bulls. SIGNIFICANCE: The saying "Bull is more than half of the herd" signifies the importance of bull in the genetic improvement of the herd. Traditionally used semen quality tests will provide limited information about the potential fertility of bulls. The proteomics approach is a promising omics technology to understand the factors involved in male fertility. The present study identified the spermatozoal and seminal plasma proteins that are differentially regulated between high and low ERR bulls. Sperm motility-associated proteins are differentially regulated. This study if improved further, can be used to develop markers associated with semen quality which is useful for the selection of bulls.

Identification of biomarkers for bull fertility using functional genomics

Prediction of bull fertility is critical for the sustainability of both dairy and beef cattle production. Even though bulls produce ample amounts of sperm with normal parameters, some bulls may still suffer from subpar fertility. This causes major economic losses in the cattle industry because using artificial insemination, semen from one single bull can be used to inseminate hundreds of thousands of cows. Although there are several traditional methods to estimate bull fertility, such methods are not sufficient to explain and accurately predict the subfertility of individual bulls. Since fertility is a complex trait influenced by a number of factors including genetics, epigenetics, and environment, there is an urgent need for a comprehensive methodological approach to clarify uncertainty in male subfertility. The present review focuses on molecular and functional signatures of bull sperm associated with fertility. Potential roles of functional genomics (proteome, small noncoding RNAs, lipidome, metabolome) on determining male fertility and its potential as a fertility biomarker are discussed. This review provides a better understanding of the molecular signatures of viable and fertile sperm cells and their potential to be used as fertility biomarkers. This information will help uncover the underlying reasons for idiopathic subfertility.