Aldose Reductase B1 in Pig Seminal Plasma: Identification, Localization in Reproductive Tissues, and Relationship With Quality and Sperm Preservation

Proteomic analysis of high and low-motility frozen-thawed spermatozoa in yak provides important insights into the molecular mechanisms underlying sperm cryodamage

Sperm cryodamage caused by cryopreservation limits the use of frozen yak spermatozoa in artificial insemination (AI). However, the proteomic changes involved in the cryodamage of yak spermatozoa have not been investigated to date. Therefore, this study aimed to identify proteins related to freezing tolerance. Tandem mass tag (TMT) were used in combination with liquid chromatography-tandem mass spectrometry (LC-MS/MS) for identifying differentially expressed proteins (DEPs) between high-motility (HM) and low-motility (LM) frozen-thawed yak spermatozoa. A total of 116 DEPs were identified (>1.5-fold, P < 0.05); of which, 104 proteins were upregulated in HM spermatozoa and 12 proteins were upregulated in LM spermatozoa. The results of functional annotation analysis revealed that the DEPs were mainly involved in metabolic processes. A total of 20 DEPs that were abundantly expressed in HM spermatozoa were strongly associated with carbohydrate metabolism. The results of KEGG analysis revealed that the DEPs were enriched in glycolysis/gluconeogenesis, PPAR signaling pathway, and Ras signaling pathway. In addition, many antioxidant enzymes such as superoxide dismutase (SOD1), peroxiredoxin-6 (PRDX6), and Parkinson disease protein 7 (PARK7) were upregulated in HM spermatozoa, suggesting that these enzymes affect the motility of spermatozoa by regulating the levels of reactive oxygen species (ROS) in frozen-thawed spermatozoa. Altogether, the findings of this study elucidate the mechanisms through which cryopreservation affects the movement of yak spermatozoa and offer a novel basis for refining freezing techniques and modifying cryopreservation extender components.

High throughput deep proteomic analysis of seminal plasma from stallions with contrasting semen quality

Seminal plasma proteins and pathways associated with sperm motility have not been elucidated in stallions. Therefore, in the current study, using the high throughput LC/MS-MS approach, we profiled stallion seminal plasma proteins and identified the proteins and pathways associated with sperm motility. Seminal plasma from six stallions producing semen with contrasting sperm motility (n = 3 each high-and low-motile group) was utilized for proteomic analysis. We identified a total of 1687 proteins in stallion seminal plasma, of which 1627 and 1496 proteins were expressed in high- (HM) and low- motile (LM) sperm of stallions, respectively. A total number of 1436 proteins were co-expressed in both the groups; 191 (11%) and 60 (3.5%) proteins were exclusively detected in HM and LM groups, respectively. A total of 220 proteins were upregulated (>1-fold change) and 386 proteins were downregulated in SP from LM group stallions as compared to HM group stallions, while 830 proteins were neutrally expressed in both the groups. Gene ontology and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis revealed dysregulation of the important proteins related to mitochondrial function, acrosome, and sperm cytoskeleton in the seminal plasma of stallions producing ejaculates with low sperm motility. High abundance of peroxiredoxins and low abundance of seminal Chaperonin Containing TCP1 Complex (CCT) complex and Annexins indicate dysregulated oxidative metabolism, which might be the underlying etiology for poor sperm motility in LM group stallions. In conclusion, the current study identified the seminal plasma proteomic alterations associated with poor sperm motility in stallions; the results indicate that poor sperm motility in stallions could be associated with altered expression of seminal plasma proteins involved in oxidative metabolism.

Aldose Reductase B1 in Pig Sperm Is Related to Their Function and Fertilizing Ability

Aldose reductase B1 (AKR1B1) has been reported to participate in the modulation of male and female reproductive physiology in several mammalian species. In spite of this, whether or not AKR1B1 could be related to sperm quality, functionality and fertilizing ability is yet to be elucidated. The present study, therefore, aimed to investigate: i) the presence of AKR1B1 in epididymal and ejaculated sperm; ii) the relationship between the AKR1B1 present in sperm and the physiology of the male gamete; iii) the liaison between the relative content of AKR1B1 in sperm and their ability to withstand preservation for 72 h; and iv) the potential link between sperm AKR1B1 and in vitro fertility outcomes. Immunoblotting revealed that AKR1B1 is present in both epididymal and ejaculated sperm with a similar relative content. Moreover, the relative levels of AKR1B1 in sperm (36 kDa band) were found to be negatively related to several kinematic parameters and intracellular calcium levels, and positively to the percentage of sperm with distal cytoplasmic droplets after storage. Finally, AKR1B1 amounts in sperm (36 kDa band) were negatively associated to fertilization rate at two days post-fertilization and embryo development at six days post-fertilization. The results of the present work suggest that AKR1B1 in sperm is probably acquired during maturation rather than at ejaculation and could play a role in that process. Moreover, AKR1B1 seems to be related to the sperm resilience to preservation and to their fertilizing capacity, as lower levels of the 36 kDa band (putative inactive form of this protein) result in better reproductive outcomes.