Proteomics: A valuable approach to elucidate spermatozoa post –testicular maturation in the endangered Acipenseridae family

Proteomic Insights into Seminal Plasma and Spermatozoa Proteins of Small-Spotted Catsharks, Scyliorhinus canicula: Implications for Reproductive Conservation in Aquariums

In the ex situ conservation of chondrichthyan species, successful reproduction in aquaria is essential. However, these species often exhibit reduced reproductive success under human care. A key aspect is that conventional sperm analyses do not provide insights into the functional competence of sperm. However, proteomics analysis enables a better understanding of male physiology, gaining relevance as a powerful tool for discovering protein biomarkers related to fertility. The present work aims to build the first proteome database for shark semen and to investigate the proteomic profiles of seminal plasma and spermatozoa from small-spotted catsharks (Scyliorhinus canicula) related to the underlying adaptations to both natural and aquarium environments, thereby identifying the reproductive impact in aquarium specimens. A total of 305 seminal plasma and 535 spermatozoa proteins were identified. Among these, 89 proteins (29.2% of the seminal plasma set) were common to both spermatozoa and seminal plasma. In the seminal plasma, only adenosylhomocysteinase protein showed differential abundance (DAP) between wild and aquarium animals. With respect to the spermatozoa proteins, a total of 107 DAPs were found between groups. Gene Ontology enrichment analysis highlighted the primary functional roles of these DAPs involved in oxidoreductase activity. Additionally, KEGG analysis indicated that these DAPs were primarily associated with metabolic pathways and carbon metabolism. In conclusion, we have successfully generated an initial proteome database for S. canicula seminal plasma and spermatozoa. Furthermore, we have identified protein variations, predominantly within spermatozoa, between aquarium and wild populations of S. canicula. These findings provide a foundation for future biomarker discovery in shark reproduction studies. However, additional research is required to determine whether these protein variations correlate with reproductive declines in captive sharks.

Sperm acrosomal released proteome reveals MDH and VDAC3 from mitochondria are involved in acrosome formation during spermatogenesis in Eriocheir sinensis

Acrosome is inextricably related to membranous organelles. The origin of acrosome is still controversial, one reason is that limited articles were reported about the proteomic analysis of the acrosome. Mitochondrial proteins were found exist in the acrosome, nevertheless, only limited attention has been paid to the function of mitochondrial proteins in the acrosome formation. Eriocheir sinensis sperm has a large acrosome, which makes it an ideal model to study acrosome formation. Here, we firstly compared the rate of acrosome reaction induced by the calcium ionophore A23187 and ionomycin. The rate of acrosome reaction induced by ionomycin is higher (95.8%) than A23187 (58.7%). Morphological changes were observed using light, confocal and transmission electron microscopy. Further more, proteins released during the acrosome reaction as induced by ionomycin were collected for LC-MS/MS analysis. A total of 945 proteins, including malate dehydrogenase (MDH) and voltage-dependent anion channel 3 (VDAC3), were identified in the acrosomal released proteome. The number of proteins from mitochondria (17.57%) was higher compared with endoplasmic reituculum (1.59%) and lysosomes (1.8%). To investigate the functions of target mitochondrial proteins during spermatogenesis, poly-antibodies of MDH in E. sinensis were prepared. The characteristics, further analyzed using immunofluorescence, of two mitochondrial proteins during acrosome formation showed that MDH and VDAC3 were independently involved in the formation of acrosomal membrane. These findings illustrate the acrosomal released proteome and provide important data resource for understanding the relationship between mitochondria and the acrosome in Decapoda crustacean.

Protein Identification of Seminal Plasma in Bali Bull (Bos javanicus)

The purpose of this study was to identify seminal plasma proteins in Bali bull and their potential as biomarkers of fertility. Semen was collected from 10 bulls aged 5-10 years using an artificial vagina. Fresh semen was then centrifuged (3000× g for 30 min). The supernatant was put into straws and stored in liquid nitrogen. The semen plasma protein concentration was determined using the Bradford method, and the protein was characterized using 1D-SDS-PAGE. Coomassie Brilliant Blue (CBB) was used to color the gel, and the molecular weight of the protein was determined using PM2700. A total of 94 proteins were identified in the seminal plasma of Bali bulls analyzed using LC-MS/MS (liquid chromatography-mass spectrometry). Proteins spermadhesin 1 (SPADH1), C-type natriuretic peptide (NPPC), clusterin (CLU), apoliprotein A-II (APOA2), inositol-3-phosphate synthase 1 (ISYNA1), and sulfhydryl oxidase 1 (QSOX1) were identified as important for fertility in Bos javanicus. These proteins may prove to be important biomarkers of fertility in Bali bulls. These proteins are important for reproductive function, which includes spermatozoa motility, capacitation, and acrosome reactions. This study provides new information about the protein content in seminal plasma in Bali bulls. The LC-MS/MS-based proteome approach that we applied in this study obtained 94 proteins. The identification of these seminal plasma proteins of Bali bulls and their potential as fertility biomarkers may have an impact on the success of future artificial insemination (AI).