Sperm ubiquitination in epididymal feline semen

Serine metabolism during differentiation of human iPSC-derived astrocytes

Astrocytes are essential players in development and functions, being particularly relevant as regulators of brain energy metabolism, ionic homeostasis and synaptic transmission. They are also the major source of l-serine in the brain, which is synthesized from the glycolytic intermediate 3-phosphoglycerate through the phosphorylated pathway. l-Serine is the precursor of the two main co-agonists of the N-methyl-d-aspartate receptor, glycine and d-serine. Strikingly, dysfunctions in both l- and d-serine metabolism are associated with neurological and psychiatric disorders. Here, we exploited a differentiation protocol, based on the generation of human mature astrocytes from neural stem cells, and investigated the modification of the proteomic and metabolomic profile during the differentiation process. We show that differentiated astrocytes are more similar to mature rather than to reactive ones, and that axogenesis and pyrimidine metabolism increase up to 30 days along with the folate cycle and sphingolipid metabolism. Consistent with the proliferation and cellular maturation processes that are taking place, also the intracellular levels of l-serine, glycine, threonine, l- and d-aspartate (which level is unexpectedly higher than that of d-serine) show the same biosynthetic time course. A significant utilization of l-serine from the medium is apparent while glycine is first consumed and then released with a peak at 30 days, parallel to its intracellular level. These results underline how metabolism changes during astrocyte differentiation, highlight that d-serine synthesis is restricted in differentiated astrocytes and provide a valuable model for developing potential novel therapeutic approaches to address brain diseases, especially the ones related to serine metabolism alterations.

Postmortem Collection of Gametes for the Conservation of Endangered Mammals: A Review of the Current State-of-the-Art

The collection of gametes from recently deceased domestic and wildlife mammals has been well documented in the literature. Through the utilization of gametes recovered postmortem, scientists have successfully produced embryos in 10 different wildlife species, while in 2 of those, offspring have also been born. Thus, the collection of gametes from recently deceased animals represents a valuable opportunity to increase genetic resource banks, obviating the requirement for invasive procedures. Despite the development of several protocols for gamete collection, the refinement of these techniques and the establishment of species-specific protocols are still required, taking into account both the limitations and the opportunities. In the case of wildlife, the optimization of such protocols is impeded by the scarcity of available animals, many of which have a high genetic value that must be protected rather than utilized for research purposes. Therefore, optimizing protocols for wildlife species by using domestic species as a model is crucial. In this review, we focused on the current advancements in the collection, preservation, and utilization of gametes, postmortem, in selected species belonging to Equidae, Bovidae, and Felidae, both domestic and wildlife.

Mass spectrometry-based proteomic strategy for ecchymotic skin examination in forensic pathology

Mass spectrometry (MS)-based proteomics has recently attracted the attention from forensic pathologists. This work is the first report of the development of a shotgun bottom-up proteomic approach based on rapid protein extraction and nano-liquid chromatography/high-resolution mass spectrometry applied to full-thickness human skin for the differential analysis of normal and ecchymotic tissues to identify new biomarkers for bruise characterization and dating. We identified around 2000 proteins from each pooled extract. The method showed excellent precision on independent replicates, with Pearson correlation coefficients always higher than 95%. Glycophorin A, a known biomarker of vital wounds from immunochemical studies, was identified only in ecchymotic tissues, as confirmed by Western blotting analysis. This finding suggests that this protein can be used as a MS-detectable biomarker of wound vitality. By focusing on skin samples from individuals with known wound dating, besides Glycophorin A, other proteins differentially expressed in ecchymotic samples and dependant on wound age were identified, although further analysis on larger datasets are needed to validate these findings. This study paves the way for an in-depth investigation of the potential of MS-based techniques for wound examination in forensic pathology, overcoming the limitations of immunochemical assays.

Molecular response of Sargassum vulgare to acidification at volcanic CO2 vents: Insights from proteomic and metabolite analyses

Ocean acidification is impacting marine life all over the world. Understanding how species can cope with the changes in seawater carbonate chemistry represents a challenging issue. We addressed this topic using underwater CO2 vents that naturally acidify some marine areas off the island of Ischia. In the most acidified area of the vents, having a mean pH value of 6.7, comparable to far-future predicted acidification scenarios (by 2300), the biomass is dominated by the brown alga Sargassum vulgare. The novelty of the present study is the characterization of the S. vulgare proteome together with metabolite analyses to identify the key proteins, metabolites, and pathways affected by ocean acidification. A total of 367 and 387 proteins were identified in populations grown at pH that approximates the current global average (8.1) and acidified sites, respectively. Analysis of their relative abundance revealed that 304 proteins are present in samples from both sites: 111 proteins are either higher or exclusively present under acidified conditions, whereas 120 proteins are either lower or present only under control conditions. Functionally, under acidification, a decrease in proteins related to translation and post-translational processes and an increase of proteins involved in photosynthesis, glycolysis, oxidation-reduction processes, and protein folding were observed. In addition, small-molecule metabolism was affected, leading to a decrease of some fatty acids and antioxidant compounds under acidification. Overall, the results obtained by proteins and metabolites analyses, integrated with previous transcriptomic, physiological, and biochemical studies, allowed us to delineate the molecular strategies adopted by S. vulgare to grow in future acidified environments, including an increase of proteins involved in energetic metabolism, oxidation-reduction processes, and protein folding at the expense of proteins involved in translation and post-translational processes.

Proteomic Analysis of Intracellular and Membrane-Associated Fractions of Canine (Canis lupus familiaris) Epididymal Spermatozoa and Sperm Structure Separation

Simple Summary

Epididymal spermatozoa have great potential in current dog reproductive technologies. In the case of azoospermia or when the male dies, the recovery of epididymal spermatozoa opens new possibilities for reproduction. It is of great importance to analyze the quality of the sperm in such cases. Proteomic studies contribute to explaining the role of proteins at various stages of epididymal sperm maturation and offer potential opportunities to use them as markers of sperm quality. The present study showed, for the first time, mass spectrometry and bioinformatic analysis of intracellular and membrane-associated proteins of canine epididymal spermatozoa. Additionally, sonication was used for the separation of dog epididymal sperm morphological elements (heads, tails and acrosomes). The results revealed the presence of differentially abundant proteins in both sperm protein fractions significant for sperm function and fertilizing ability. It was also shown that these proteins participate in important sperm metabolic pathways, which may suggest their potential as sperm quality biomarkers.

Abstract

This study was provided for proteomic analysis of intracellular and membrane-associated fractions of canine (Canis lupus familiaris) epididymal spermatozoa and additionally to find optimal sonication parameters for the epididymal sperm morphological structure separation and sperm protein isolation. Sperm samples were collected from 15 dogs. Sperm protein fractions: intracellular (SIPs) and membrane-associated (SMAPs) were isolated. After sonication, sperm morphology was evaluated using Spermac Stain™. The sperm protein fractions were analyzed using gel electrophoresis (SDS-PAGE) and nanoliquid chromatography coupled to quadrupole time-of-flight mass spectrometry (NanoLC-Q-TOF/MS). UniProt database-supported identification resulted in 42 proteins identified in the SIPs and 153 proteins in the SMAPs. Differentially abundant proteins (DAPs) were found in SIPs and SMAPs. Based on a gene ontology analysis, the dominant molecular functions of SIPs were catalytic activity (50%) and binding (28%). Hydrolase activity (33%) and transferase activity (21%) functions were dominant for SMAPs. Bioinformatic analysis of SIPs and SMAPs showed their participation in important metabolic pathways in epididymal sperm, which may suggest their potential as sperm quality biomarkers. The use of sonication 150 W, 10 min, may be recommended for the separation of dog epididymal sperm heads, tails, acrosomes and the protein isolation.

Canine and Feline Epididymal Semen-A Plentiful Source of Gametes

Simple Summary

The epididymis is a source of fertile spermatozoa. For some males, preserving spermatozoa that are stored in the epididymis might be an ultimate attempt for gamete preservation. The quality of epididymal semen is different from ejaculated semen in various animal species. Although assisted reproductive technologies (ART) have been introduced in cats as a tool to preserve valuable genetics of endangered wild felids, epididymal semen cryopreservation is still suboptimal in dogs. Therefore, in this paper, we carried out a review to list the morphological changes of spermatozoa during epididymal transit alongside with the potential that holds in the epididymal semen in dogs and cats. We believe that better comprehension of epididymal semen collection method, quality and freezability may aid in optimizing cryopreservation and enhance different applications of ART.

Abstract

Canine and feline epididymal semen provide an additional source of gametes to preserve the genetics of valuable breeding dogs and tomcats, especially for those that fail to ejaculate, need castration as a therapy or die unexpectedly. Moreover, since it is quite common to perform castration of non-breeding dogs and cats, the development of a gene bank of epididymal semen collected after castration would greatly contribute to increase the genetic diversity in dogs and cats. Collection and cryopreservation of epididymal semen necessitates a full understanding of the function of the epididymis and of the characteristics of epididymal spermatozoa as opposed to ejaculated semen. During collection of epididymal semen, specific factors may have a negative effect on epididymal semen quality and freezability. Accordingly, the elimination of these triggers could enhance epididymal semen freezability and consequently positively influence post-thaw semen quality and outcome for different ARTs.

Multi-omic analyses in Abyssinian cats with primary renal amyloid deposits

The amyloidoses constitute a group of diseases occurring in humans and animals that are characterized by abnormal deposits of aggregated proteins in organs, affecting their structure and function. In the Abyssinian cat breed, a familial form of renal amyloidosis has been described. In this study, multi-omics analyses were applied and integrated to explore some aspects of the unknown pathogenetic processes in cats. Whole-genome sequences of two affected Abyssinians and 195 controls of other breeds (part of the 99 Lives initiative) were screened to prioritize potential disease-associated variants. Proteome and miRNAome from formalin-fixed paraffin-embedded kidney specimens of fully necropsied Abyssinian cats, three affected and three non-amyloidosis-affected were characterized. While the trigger of the disorder remains unclear, overall, (i) 35,960 genomic variants were detected; (ii) 215 and 56 proteins were identified as exclusive or overexpressed in the affected and control kidneys, respectively; (iii) 60 miRNAs were differentially expressed, 20 of which are newly described. With omics data integration, the general conclusions are: (i) the familial amyloid renal form in Abyssinians is not a simple monogenic trait; (ii) amyloid deposition is not triggered by mutated amyloidogenic proteins but is a mix of proteins codified by wild-type genes; (iii) the form is biochemically classifiable as AA amyloidosis.

Acute environmental temperature variation affects brain protein expression, anxiety and explorative behaviour in adult zebrafish

This study investigated the effect of 4-d acute thermal treatments at 18 °C, 26 °C (control) and 34 °C on the nervous system of adult zebrafish (Danio rerio) using a multidisciplinary approach based on behavioural tests and brain proteomic analysis. The behavioural variations induced by thermal treatment were investigated using five different tests, the novel tank diving, light and dark preference, social preference, mirror biting, and Y-Maze tests, which are standard paradigms specifically tailored for zebrafish to assess their anxiety-like behaviour, boldness, social preference, aggressiveness, and explorative behaviour, respectively. Proteomic data revealed that several proteins involved in energy metabolism, messenger RNA translation, protein synthesis, folding and degradation, cytoskeleton organisation and synaptic vesiculation are regulated differently at extreme temperatures. The results showed that anxiety-like behaviours increase in zebrafish at 18 °C compared to those at 26 °C or 34 °C, whereas anxiety-related protein signalling pathways are downregulated. Moreover, treatments at both 18 °C and 34 °C affect the exploratory behaviour that appears not to be modulated by past experiences, suggesting the impairment of fish cognitive abilities. This study is the continuation of our previous work on the effect of 21-d chronic treatment at the same constant temperature level and will enable the comparison of acute and chronic treatment effects on the nervous system function in adult zebrafish.

Integrated analysis of phosphoproteome and ubiquitylome in epididymal sperm of buffalo (Bubalus bubalis)

In mammals, sperm need to mature in the epididymis to gain fertilization competency. However, the molecular mechanism underlying buffalo sperm maturation remains elusive. Exploring sperm physiology at the posttranslational modification (PTM) level could help to develop our understanding of these mechanisms. Protein phosphorylation and ubiquitination are major PTMs in the regulation of many biological processes. In the present study, to our knowledge, we report the first phosphoproteome and ubiquitylome of sperm collected from the caput, corpus, and cauda segments of the epididymis using liquid chromatography-mass spectrometry combined with affinity purification. In total, 647 phosphorylation sites in 294 proteins and 1063 ubiquitination sites in 446 proteins were characterized. Some of these proteins were associated with cellular developmental processes and energy metabolic pathways. Interestingly, 84 proteins were both phosphorylated and ubiquitinated, simultaneously. Some of these proteins were involved in, for example, spermatogenesis, reproduction, and spermatid development. Taken together, these data provide a theoretical basis for further functional analysis of phosphorylation and ubiquitination in epididymal sperm of buffalo and other mammals, and serve as an important resource for exploring the physiological mechanism underlying sperm maturation.

Methionine Supplementation Affects Metabolism and Reduces Tumor Aggressiveness in Liver Cancer Cells

Liver cancer is one of the most common cancer worldwide with a high mortality. Methionine is an essential amino acid required for normal development and cell growth, is mainly metabolized in the liver, and its role as an anti-cancer supplement is still controversial. Here, we evaluate the effects of methionine supplementation in liver cancer cells. An integrative proteomic and metabolomic analysis indicates a rewiring of the central carbon metabolism, with an upregulation of the tricarboxylic acid (TCA) cycle and mitochondrial adenosine triphosphate (ATP) production in the presence of high methionine and AMP-activated protein kinase (AMPK) inhibition. Methionine supplementation also reduces growth rate in liver cancer cells and induces the activation of both the AMPK and mTOR pathways. Interestingly, in high methionine concentration, inhibition of AMPK strongly impairs cell growth, cell migration, and colony formation, indicating the main role of AMPK in the control of liver cancer phenotypes. Therefore, regulation of methionine in the diet combined with AMPK inhibition could reduce liver cancer progression.

High-Resolution Mass Spectrometry-Based Approaches for the Detection and Quantification of Peptidase Activity in Plasma

Proteomic technologies have identified 234 peptidases in plasma but little quantitative information about the proteolytic activity has been uncovered. In this study, the substrate profile of plasma proteases was evaluated using two nano-LC-ESI-MS/MS methods. Multiplex substrate profiling by mass spectrometry (MSP-MS) quantifies plasma protease activity in vitro using a global and unbiased library of synthetic peptide reporter substrates, and shotgun peptidomics quantifies protein degradation products that have been generated in vivo by proteases. The two approaches gave complementary results since they both highlight key peptidase activities in plasma including amino- and carboxypeptidases with different substrate specificity profiles. These assays provide a significant advantage over traditional approaches, such as fluorogenic peptide reporter substrates, because they can detect active plasma proteases in a global and unbiased manner, in comparison to detecting select proteases using specific reporter substrates. We discovered that plasma proteins are cleaved by endoproteases and these peptide products are subsequently degraded by amino- and carboxypeptidases. The exopeptidases are more active and stable in plasma and therefore were found to be the most active proteases in the in vitro assay. The protocols presented here set the groundwork for studies to evaluate changes in plasma proteolytic activity in shock.

Proteomic Analysis Reveals a Mitochondrial Remodeling of βTC3 Cells in Response to Nanotopography

Recently, using cluster-assembled zirconia substrates with tailored roughness produced by supersonic cluster beam deposition, we demonstrated that β cells can sense nanoscale features of the substrate and can translate these stimuli into a mechanotransductive pathway capable of preserveing β-cell differentiation and function in vitro in long-term cultures of human islets. Using the same proteomic approach, we now focused on the mitochondrial fraction of βTC3 cells grown on the same zirconia substrates and characterized the morphological and proteomic modifications induced by the nanostructure. The results suggest that, in βTC3 cells, mitochondria are perturbed by the nanotopography and activate a program involving metabolism modification and modulation of their interplay with other organelles. Data were confirmed in INS1E, a different β-cell model. The change induced by the nanostructure can be pro-survival and prime mitochondria for a metabolic switch to match the new cell needs.

Selection for bull fertility: a review

Fertility is a critically important factor in cattle production because it directly relates to the ability to produce the offspring necessary to offset costs in production systems. Female fertility has received much attention and has been enhanced through assisted reproductive technologies, as well as genetic selection; however, improving bull fertility has been largely ignored. Improvements in bull reproductive performance are necessary to optimize the efficiency of cattle production. Selection and management to improve bull fertility not only have the potential to increase conception rates but also have the capacity to improve other economically relevant production traits. Bull fertility has reportedly been genetically correlated with traits such as average daily gain, heifer pregnancy, and calving interval. Published studies show that bull fertility traits are low to moderately heritable, indicating that improvements in bull fertility can be realized through selection. Although female fertility has continued to progress according to increasing conception rates, the reported correlation between male and female fertility is low, indicating that male fertility cannot be improved by selection for female fertility. Correlations between several bull fertility traits, such as concentration, number of spermatozoa, motility, and number of spermatozoa abnormalities, vary among studies. Using male fertility traits in selection indices would provide producers with more advanced selection tools. The objective of this review was to discuss current beef bull fertility measurements and to discuss the future of genetic evaluation of beef bull fertility and potential genetic improvement strategies.

Seminal plasma and sperm proteome of ring-tailed coatis (Nasua nasua, Linnaeus, 1766)

Ring-tailed coati is listed as a species of least concern in the International Union for Conservation of Nature (IUCN) Red List, however, there has been a sharp decline in their population. The present study was conducted to evaluate the major proteins of both seminal plasma and sperm in ring-tailed coatis. Semen sample was collected from three adult coatis and evaluated for their morphological characteristics. Further, the sample was centrifuged to separate spermatozoa from seminal plasma, and then stored in liquid nitrogen. The seminal plasma and sperm proteins were subjected to one-dimensional (1-D) sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and identified by mass spectrometry. Gene ontology and protein networks were analyzed using bioinformatics tools. Based on sperm concentration and average protein content of the semen, the concentration of protein/spermatozoon was found to be 104.69 ± 44.43 μg. The analysis of SDS-PAGE gels showed 20.3 ± 3.1 and 17 ± 2 protein bands/lane for seminal plasma and sperm, respectively. In-gel protein digestion and peptide analysis by mass spectrometry revealed 238 and 246 proteins in the seminal plasma and sperm, respectively. The gene ontology analysis revealed that the proteins of seminal plasma mainly participated in cellular (35%) and regulatory (21%) processes. According to their cellular localization, seminal plasma proteins were categorized as structural (18%), extracellular (17%), and nuclear (14%) proteins with molecular functions, such as catalytic activity (43%) and binding (43%). The sperm proteins were also involved in cellular (38%) and regulatory (23%) processes, and mainly categorized as extracellular (17%), nuclear (13%), and cytoplasmic (10%) proteins. The major molecular functions of the sperm proteins were catalytic activity (44%) and binding (42%). These results indicated that the seminal plasma of ring-tailed coati has an array of proteins that can potentially modulate several sperm functions, from sperm protection to oocyte binding. However, further studies are necessary to interpret the roles of these major seminal plasma proteins in coatis.

Genome-wide mapping and estimation of inbreeding depression of semen quality traits in a cattle population

Inbreeding depression is known to affect quantitative traits such as male fertility and sperm quality, but the genetic basis for these associations is poorly understood. Most studies have been limited to examining how pedigree- or marker-derived genome-wide autozygosity is associated with quantitative phenotypes. In this study, we analyzed possible associations of genetic features of inbreeding depression with percentage of live spermatozoa and total number of spermatozoa in 19,720 ejaculates obtained from 554 Austrian Fleckvieh bulls during routine artificial insemination programs. Genome-wide inbreeding depression was estimated and genomic regions contributing to inbreeding depression were mapped. Inbreeding depression did affect total number of spermatozoa, and such depression was predicted by pedigree-based inbreeding levels and genome-wide inbreeding levels based on runs of homozygosity (ROH). Genome-wide inbreeding depression did not seem to affect percentage of live spermatozoa. A model incorporating genetic effects of the bull, environmental factors, and additive genetic and ROH status effects of individual single-nucleotide polymorphisms revealed genomic regions significantly associated with ROH status for total number of spermatozoa (4 regions) or percentage of live spermatozoa (5 regions). All but one region contains genes related to spermatogenesis and sperm morphology. These genomic regions contain genes affecting sperm morphogenesis and efficacy. The results highlight that next-generation sequencing may help explain some of the genetic factors contributing to inbreeding depression of sperm quality traits in Fleckvieh bulls.

Proteomic profile of maternal-aged blastocoel fluid suggests a novel role for ubiquitin system in blastocyst quality

PURPOSE

The etiology of maternal aging, a common cause of female factor infertility and a rate-limiting step in vitro fertilization (IVF) success, remains still unclear. Proteomic changes responsible for the impaired successful pregnancy outcome after IVF with aged blastocysts have not been yet evaluated. The objective of this prospective study was to employ proteomic techniques and bioinformatic tools to enlight differences at the protein level in blastocoel fluid of aged and younger woman.

METHODS

Protein composition of human blastocoel fluid isolated by micromanipulation from 46 blastocysts of women aged <37 years (group A) and 29 of women aged ≥37 years (group B) have been identified by a shotgun proteomic approach based on high-resolution nano-liquid chromatography electrospray-ionization-tandem mass spectrometry (nLC-ESI-MS/MS) using label free for the relative quantification of their expression levels.

RESULTS

The proteomic analysis leads to the identification and quantification of 148 proteins; 132 and 116 proteins were identified in groups A and B, respectively. Interestingly, the identified proteins are mainly involved in processes aimed at fine tuning embryo implantation and development. Among the 100 proteins commonly expressed in both groups, 17 proteins are upregulated and 44 downregulated in group B compared to group A. Overall, the analysis identified 33 proteins, which were increased or present only in B while 76 were decreased in B or present only in A.

CONCLUSIONS

Data revealed that maternal aging mainly affects blastocyst survival and implantation through unbalancing the equilibrium of the ubiquitin system known to play a crucial role in fine-tuning several aspects required to ensure successful pregnancy outcome.

Negative biomarker based male fertility evaluation: Sperm phenotypes associated with molecular-level anomalies

Biomarker-based sperm analysis elevates the treatment of human infertility and ameliorates reproductive performance in livestock. The negative biomarker-based approach focuses on proteins and ligands unique to defective spermatozoa, regardless of their morphological phenotype, lending itself to analysis by flow cytometry (FC). A prime example is the spermatid specific thioredoxin SPTRX3/TXNDC8, retained in the nuclear vacuoles and superfluous cytoplasm of defective human spermatozoa. Infertile couples with high semen SPTRX3 are less likely to conceive by assisted reproductive therapies (ART) and more prone to recurrent miscarriage while low SPTRX3 has been associated with multiple ART births. Ubiquitin, a small, proteolysis-promoting covalent posttranslational protein modifier is found on the surface of defective posttesticular spermatozoa and in the damaged protein aggregates, the aggresomes of spermiogenic origin. Semen ubiquitin content correlates negatively with fertility and conventional semen parameters, and with sperm binding of lectins LCA (Lens culinaris agglutinin; reveals altered sperm surface) and PNA (Arachis hypogaea/peanut agglutinin; reveals acrosomal malformation or damage). The Postacrosomal Sheath WWI Domain Binding Protein (PAWP), implicated in oocyte activation during fertilization, is ectopic or absent from defective human and animal spermatozoa. Consequently, FC-parameters of PAWP correlate with ART outcomes in infertile couples and with fertility in bulls. Assays based on the above biomarkers have been combined into multiplex FC semen screening protocols, and the surface expression of lectins and ubiquitin has been utilized to develop nanoparticle-based bull semen purification method validated by field artificial insemination trials. These advances go hand-in-hand with the innovation of FC-technology and genomics/proteomics-based biomarker discovery.