Implications of sperm heat shock protein 70-2 in bull fertility

Harnessing the value of fertility biomarkers in bull sperm for buck sperm

Efficient and sustainable reproduction and production of cattle and goats are vitally important for ensuring global food security. There is a need for potent biomarkers to accurately evaluate semen quality and predict male fertility. Although there is a reasonable set of biomarkers identified in bull sperm, there is a significant lack of such information in buck sperm along with a lack of transfer of proven technologies in goat reproductive biotechnology. These gaps are important problems because they are preventing advances in fundamental andrology and applied science of goat production. Both cattle and goats are ruminants, and they share significant similarities in their genetics and physiology although subtle differences do exist. This review harnesses the power of utilizing the knowledge developed in bull sperm to generate information on buck sperm fertility markers. These include genomic, functional genomic, epigenomic fertility markers. Revealing molecular underpinnings of such similarity and diversity using systems biology is expected to advance both fundamental and applied andrology of livestock and endangered species.

Sperm protein profile and their correlation with frozen semen quality of indigenous Indonesian buffalo bulls

Objective

The study aimed to assess sperm motility characteristics, kinematic parameters, and sperm protein molecular weight (MW) in Indonesian buffalo to predict fertility.

Materials and Methods

Frozen semen from Silangit (4 bulls), Murrah (4 bulls), and Toraya (2 bulls)-aged 7-10 years, was analyzed. Sperm motility was assessed using Computer Assisted Semen Analysis, viability and abnormality were evaluated using eosin-nigrosin staining, plasma membrane integrity was evaluated using the hypoosmotic swelling test, acrosomal status was evaluated using lectin peanut agglutinin, protamine deficiency was evaluated using chromomycin A3, and deoxyribonucleic acid (DNA) integrity was evaluated using Halomax. Protein concentration was determined using the bicinchoninic acid method and characterized with sodium dodecyl sulfate-polyacrylamide gel electrophoresis.

Results

The study revealed breed-specific variations in semen quality. Silangit buffaloes exhibited lower DNA integrity, while Murrah buffaloes showed elevated motility and membrane integrity. Toraya buffaloes displayed higher normal morphology and protamine status, though they had lower viability. Notable differences in protein expression included the presence of SPAG9 and the absence of IZUMO1 in Toraya buffaloes. Protein MW analysis further showed correlations with sperm characteristics. In Murrah buffaloes, proteins within the 130-125 kilodalton (kDa) range were negatively correlated with acrosome integrity, whereas in Toraya buffaloes, proteins within the 55-50 kDa range were negatively correlated with sperm abnormalities. Silangit buffaloes showed a positive correlation between proteins at 32 kDa and sperm abnormalities.

Conclusion

Analyzing protein MW through SDS-PAGE provides a promising approach for assessing semen quality in indigenous Indonesian buffalo bulls. Although the semen quality of the buffaloes in this study was variable, all bulls met the established Indonesian standards for semen quality and exhibited adequate fertilization potential. These results provide valuable insights into the reproductive biology of Indonesian buffalo bulls and form the basis for predicting fertility capacity through a comprehensive analysis of sperm characteristics and molecular profiles of sperm proteins.

The frozen-thawed sperm protein of Indonesian Toraya buffaloes is significantly associated with sperm kinematics, acrosome integrity, and mitochondrial membrane potential

Objective

The study aimed to characterize frozen-thawed sperm proteins and their correlation with sperm kinematics, acrosome integrity, and mitochondrial membrane potential (MMP) in Indonesian Toraya buffalo bulls.

Materials and Methods

Semen was obtained from six Toraya buffaloes classified as Saleko and Bonga 4-10 years old. The frozen semen was analyzed for sperm motility, sperm kinematics, viability, abnormalities, membrane integrity, intact acrosome, MMP, DNA integrity, and sperm protamine (PRM) deficiency. Sperm protein concentration (Prot. Con) was determined by the bicinchoninic acid, and protein molecular weight (MW) was determined using 1D sodium dodecyl sulfate-polyacrylamide gel electrophoresis with 4%-20% gradient gel and 6.5-240 kDa protein marker.

Results

The results of this study showed that the quality of frozen semen from Toraya buffalo bulls is in a good category and suitable for use in artificial insemination programs. The sperm quality differed significantly (p < 0.05) between individuals, immunofluorescence examination of intact acrosome, PRM deficiency, intact MMP, and intact DNA showed no significant difference (p < 0.05). Pearson correlations in this study showed that sperm Prot. Con has a significant correlation (p < 0.05) with acrosome integrity. The sperm protein band (Prot. Band) correlated significantly (p < 0.05) with sperm kinematic parameters and intact MMP. The average sperm Prot. Con of Toraya buffalo was 77.29 ± 39.26 µg/ml and 4-13 Prot. Bands with 6-240 kDa of MW were detected, with Prot. Bands of 16, 50, 70, and 115 kDa having higher intensity.

Conclusions

Frozen-thawed sperm protein is correlated with sperm kinematics, acrosome integrity, and MMP. The proteins were found to correlate with sperm quality and fertility in Toraya buffalo bulls.

A Comparison of White and Yellow Seminal Plasma Phosphoproteomes Obtained from Turkey (Meleagris gallopavo) Semen

Seminal plasma is rich in proteins originating from various male reproductive organs. The phosphorylation of these proteins can significantly impact sperm motility, capacitation, and acrosome reaction. Phosphoproteomics identifies, catalogues, and characterizes phosphorylated proteins. The phosphoproteomic profiling of seminal plasma offers valuable insights into the molecular mechanisms that influence semen quality and male fertility. Thus, the aim of this study was a phosphoproteomic analysis of white and yellow turkey seminal plasma. The experimental material consisted of 100 ejaculates from BIG-6 turkeys between 39 and 42 weeks of age. The collected white and yellow turkey seminal plasmas were analyzed for total protein content; the activity of selected enzymes, i.e., alkaline phosphatase (ALP), acid phosphatase (ACP), superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase (CAT); and the content of reduced glutathione (GSH) and malondialdehyde (MDA). Phosphoproteins were isolated from white and yellow seminal fluids, and the resulting protein fractions were separated by SDS-PAGE and Western blotting. Phosphorylated residues were immunodetected, and the isolated phosphoproteins were identified (nano LC-MS/MS). Yellow seminal plasmas were characterized by higher levels of total protein, GSH, and MDA, as well as higher levels of ALP, ACP, and GPx activity. There were no significant differences in the activity of SOD and CAT. A total of 113 phosphoproteins were identified in turkey seminal fluids. The functional analysis demonstrated that these phosphoproteins were mainly involved in oocyte fertilization, organization and metabolism of the actin cytoskeleton, amplification of the intracellular signal transduction pathway, general regulation of transport, vesicular transport, proteome composition of individual cellular compartments, and the organization and localization of selected cellular components and macromolecules. Increased phosphorylation of the fractions containing proteins encoded by SPARC, PPIB, TRFE, QSOX1, PRDX1, PRDX6, and FASN genes in white plasmas and the proteins encoded by CKB, ORM2, APOA1, SSC5D, RAP1B, CDC42, FTH, and TTH genes in yellow plasmas was observed based on differences in the optical density of selected bands. The obtained results indicate that the phosphorylation profiles of turkey seminal plasma proteins vary depending on the type of ejaculate.

High fat diet-induced obesity and gestational DMBA exposure alter folliculogenesis and the proteome of the maternal ovary†

Obesity and ovotoxicant exposures impair female reproductive health with greater ovotoxicity reported in obese relative to lean females. The mother and developing fetus are vulnerable to both during gestation. 7,12-dimethylbenz[a]anthracene (DMBA) is released during carbon combustion including from cigarettes, coal, fossil fuels, and forest fires. This study investigated the hypothesis that diet-induced obesity would increase sensitivity of the ovaries to DMBA-induced ovotoxicity and determined impacts of both obesity and DMBA exposure during gestation on the maternal ovary. Female C57BL/6 J mice were fed a control or a High Sugar High Fat (45% kcal from fat; 20% kcal from sucrose) diet until ~30% weight gain was attained before mating with unexposed males. From gestation Day 7, mice were exposed intraperitoneally to either vehicle control (corn oil) or DMBA (1 mg/kg diluted in corn oil) for 7 d. Thus, there were four groups: lean control (LC); lean DMBA exposed; obese control; obese DMBA exposed. Gestational obesity and DMBA exposure decreased (P < 0.05) ovarian and increased liver weights relative to LC dams, but there was no treatment impact (P > 0.05) on spleen weight or progesterone. Also, obesity exacerbated the DMBA reduction (P < 0.05) in the number of primordial, secondary follicles, and corpora lutea. In lean mice, DMBA exposure altered abundance of 21 proteins; in obese dams, DMBA exposure affected 134 proteins while obesity alone altered 81 proteins in the maternal ovary. Thus, the maternal ovary is impacted by DMBA exposure and metabolic status influences the outcome.

A proteomic approach to identifying spermatozoa proteins in Indonesian native Madura bulls

Proteins assist sperm mature, transit the female reproductive tract, and recognise sperm oocytes. Indigenous Indonesian bulls, Madura bulls, have not been studied for reproductive proteomics. As local Indonesian beef livestock, Madura cattle assist in achieving food security; hence, their number must be improved. Thus, the identification of molecular proteomics-based bull fertility biomarkers is needed. This study aimed to characterise the sperm fertility function of the superior Madura bull (Bos indicus × Bos Javanicus) spermatozoa proteome. Frozen semen from eight Madura superior bulls (Bos indicus × Bos javanicus) aged 4-8 years was obtained from the artificial insemination centre (AIC) in Singosari and Lembang. Madura superior bulls are those that have passed the bull breeding soundness evaluation. Frozen sperm were thawed and centrifuged at 3000 × g for 30 min. Proteins in sperm were characterised through proteomic analysis using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The resulting gene symbols for each protein were then subjected to bioinformatics tools, including UniProt, DAVID, and STRING databases. Regarding sperm fertility, the analysis revealed that 15 proteins were identified in the sperm of Madura bulls. Amongst the identified proteins, the superior Madura bull sperm contained several motilities, energy-related proteins, and chaperone proteins. A substantial portion of characterised proteins are linked to metabolic pathways and the tricarboxylic acid (TCA) cycle, contributing to sperm energy production. In conclusion, the first in-depth proteome identification of sperm related to sperm quality and bull fertility of a unique indigenous Madura breed of Indonesia was performed using the LC-MS/MS proteomic method. These findings may serve as a reference point for further studies related to the functions of bovine sperm and biomarkers of fertility and sperm quality.

Identification of heat shock protein70-2 and protamine-1 mRNA, proteins, and analyses of their association with fertility using frozen-thawed sperm in Madura bulls

OBJECTIVE

This study aims to identify heat shock protein70-2 (HSP70-2) and protamine-1 (PRM1) mRNA and protein in Madura bull sperm and demonstrate their relation as bull fertility biomarkers.

METHODS

The Madura bull fertility rates were grouped based on the percentage of first service conception rate (%FSCR) as high fertility (HF) (79.04%; n = 4), and low fertility (LF) (65.84%; n = 4). mRNA of HSP70-2 and PRM1 with peptidylprolyl isomerase A (PPIA) as a housekeeping gene were determined by quantitative real-time polymerase chain reaction, while enzyme-linked immunoassay was used to measure protein abundance. In the post-thawed semen samples, sperm motility, viability, acrosome integrity, and sperm DNA fragmentation index were analyzed. Data analysis was performed on the measured parameters of semen quality, relative mRNA expression, and protein abundance of HSP70-2 and PRM1, among the bulls with various fertility levels (HF and LF) in a one-way analysis of variance analysis. The Pearson correlation was used to analyze the relationship between semen quality, mRNA, proteins, and fertility rate.

RESULTS

Relative mRNA expression and protein abundance of HSP70-2 and PRM1 were detected and were found to be highly expressed in bulls with HF (p<0.05) and were associated with several parameters of semen quality.

CONCLUSION

HSP70-2 and PRM1 mRNA and protein molecules have great potential to serve as molecular markers for determining bull fertility.

Seasonal influence on expression of heat shock proteins (HSP70 and HSP90) vis-à-vis functional competence of Gir bull semen

The success of assisted reproduction relies on functional competence of frozen-thawed semen. Heat stress affects protein folding leading to aggregation of mis-folded proteins. Hence, a total of 384 (32 ejaculates/bull/season) ejaculates from six matured Gir bulls were used to evaluate physico-morphological parameters, the expression of HSPs (70 and 90) and fertility of frozen-thawed semen. The mean percent individual motility, viability and membrane integrity were significantly (p < 0.01) higher in winter compared to summer. Out of 1200 Gir cows inseminated, 626 confirmed pregnant and the mean conception rate of winter (55.04 ± 0.35) was significantly (p < 0.001) higher than summer (49.33 ± 0.32). A significant (p < 0.01) difference in concentration of HSP70 (ng/mg of protein) but not HSP90was observed between the two seasons. The HSP70 expression in pre-freeze semen of Gir bulls had significant positive correlation with motility (p < 0.01, r = 0.463), viability (p < 0.01, r = 0.565), acrosome integrity (p < 0.05, r = 0.330) and conception rate (p < 0.01, r = 0.431). In conclusion, the season influences physico-morphological parameters and expression of HSP70 but not HSP90 in Gir bull semen. The HSP70 expression is positively correlated with motility, viability, acrosome integrity and fertility of semen. The semen expression of HSP70 may be utilized as biomarker for thermo-tolerance, semen quality and fertilizing capacity of Gir bull semen.