Extracellular vesicles (EVs) isolated from epididymal segments of both normospermic and teratospermic domestic cats were analyzed via mass spectrometry. Both male types shared 3008 proteins, with 98 ...and 20 EV proteins unique to normospermic and teratospermic males, respectively. Expression levels of several proteins changed between epididymal segments in both male types, with seven cauda-derived proteins trending downward in teratospermic compared to normospermic males. Collectively, these differences may relate to the poor sperm quality observed in teratospermic individuals.
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Highlights•Several proteins were found to be unique to each male type.•Expression levels of seven proteins trended downward in teratospermic males.•Several proteins were related to sperm motility and subsequent oocyte binding.
Extracellular vesicles (EVs) secreted by the epididymal epithelium transfer to spermatozoa key proteins that are essential in promoting motility and subsequent fertilization success. Using the domestic cat model, the objectives were to (1) characterize and compare protein content of EVs between segments of the epididymis, and (2) compare EV protein compositions between normo- and teratospermic individuals (producing >60% of abnormal spermatozoa). Epididymal EVs from adult cats were isolated and assessed via liquid chromatography tandem MS. Both male types shared 3008 proteins in total, with 98 and 20 EV proteins unique to normospermic and teratospermic males, respectively. Expression levels of several proteins changed between epididymal segments in both male types. Several proteins in both groups were related to sperm motility (e.g. hexokinase 1, adenylate kinase isoenzyme) and zona pellucida or oolemma binding (e.g. disintegrin and metalloproteinase domain proteins, zona binding proteins 1 and 2). Interestingly, seven cauda-derived EV proteins trended downward in teratospermic compared with normospermic males, which may relate to poor sperm quality. Collective results revealed, for the first time, EV proteins related to sequential sperm maturation with differences observed between normospermic and teratospermic individuals.
Organization of existing and emerging toxicological knowledge into adverse outcome pathway (AOP) descriptions can facilitate greater application of mechanistic data, including those derived through ...high-throughput in vitro, high content omics and imaging, and biomarker approaches, in risk-based decision making. The previously ad hoc process of AOP development is being formalized through development of internationally harmonized guidance and principles. The goal of this article was to outline the information content desired for formal AOP description and some rules of thumb and best practices intended to facilitate reuse and connectivity of elements of an AOP description in a knowledgebase and network context. For example, key events (KEs) are measurements of change in biological state that are indicative of progression of a perturbation toward a specified adverse outcome. Best practices for KE description suggest that each KE should be defined as an independent measurement made at a particular level of biological organization. The concept of "functional equivalence" can help guide both decisions about how many KEs to include in an AOP and the specificity with which they are defined. Likewise, in describing both KEs and evidence that supports a causal linkage or statistical association between them (ie, a key event relationship; KER), best practice is to build from and contribute to existing KE or KER descriptions in the AOP knowledgebase rather than creating redundant descriptions. The best practices proposed address many of the challenges and uncertainties related to AOP development and help promote a consistent and reliable, yet flexible approach.
Purpose
Extracellular vesicles (EVs) secreted by the epididymal epithelium transfer key factors to maturing spermatozoa. Using an in vitro system previously developed in our laboratory, the objective ...was to (1) characterize the impact of EV exposure on the fertilizing ability and developmental potential of immature sperm cells from the caput epididymidis and (2) examine the benefit of EV exposure to restore vitality of mature spermatozoa from the cauda epididymidis after freezing-thawing.
Methods
EVs were isolated from entire epididymides and collected into pellets via ultracentrifugation. Immature spermatozoa from adult cats were isolated from the caput epididymis and incubated with EVs prior to in vitro fertilization. Similarly, mature spermatozoa were isolated from the cauda segment and cryopreserved prior to EV exposure and subsequent analysis of motility and developmental potential after fertilization.
Results
EV exposure did not affect the percentage of caput sperm penetration; however, it improved the fertilizing ability (faster pronuclear apposition) and the developmental potential (higher proportions of morula-blastocysts) of those immature sperm cells. While EV exposure was beneficial to the frozen-thawed sperm motility, it did not significantly improve the fertilizing ability and the developmental potential.
Conclusions
Epididymal EVs contain multiple factors contributing to immature sperm function, specifically enhancing the ability to complete a faster pronuclear apposition with subsequently improved early embryonic development. Supplementation was also beneficial to the motility of spermatozoa that had undergone cryopreservation. Those new findings could lead to new options for male fertility treatment in animal models and humans.
We previously reported that moderate calorie restriction (CR) has minimal impact on testicular gene expression in young adult rhesus macaques, and no obvious negative impact on semen quality or ...plasma testosterone levels. We now extend these findings by examining the influence of CR on various aspects of the reproductive axis of older males, including 24-h circulating testosterone levels, testicular gene expression, and testicular morphology. Young adult and old adult male rhesus macaques were subjected to either 30 % CR for 5–7 years, or were fed a standard control diet. Analysis of the 24-h plasma testosterone profiles revealed a significant age-associated decline, but no evidence for CR-induced suppression in either the young or old males. Similarly, expression profiling of key genes associated with testosterone biosynthesis and Leydig cell maintenance showed no significant CR-induced changes in either the young or old animals. The only evidence for CR-associated negative effects on the testis was detected in the old animals at the histological level; when old CR animals were compared with their age-matched controls, there was a modest decrease in seminiferous tubule diameter and epithelium height, with a concomitant increase in the number of depleted germ cell lines. Reassuringly, data from this study and our previous study suggest that moderate CR does not negatively impact 24-h plasma testosterone profiles or testicular gene expression. Although there appear to be some minor CR-induced effects on testicular morphology in old animals, it is unclear if these would significantly compromise fertility.
A murine monoclonal antibody (mAb, IgG2a) was produced for the detection of smallmouth bass (Micropterus dolomieu) immunoglobulin (IgM). The antibody is specific for IgM heavy chain and was shown to ...also recognize the Ig heavy chain of largemouth bass (Micropterus salmoides) and bluegill (Lepomis macrochirus) using Western Blot analysis of plasma from 9 teleost taxa. When applied to the analysis of smallmouth bass total plasma IgM using ELISA, the mAb was found to be effective when used in an inhibition kinetic assay.
•Mouse IgG2a Monoclonal antibody produced against smallmouth bass IgM.•Antibody reacts with IgM from smallmouth and largemouth bass as well as bluegill.•Application of antibody in Western Blot and ELISA demonstrated.
The neuropeptide hormone oxytocin (OT) is released peripherally and centrally and has been implicated in both physiology and behavior, especially sociosexual behaviors. Knowledge of OT levels in ...blood or other sources would be useful but these are rarely reported. Radioimmunoassay following extraction is the most commonly used method for measuring OT but is not ideal for use in small mammals in which blood volumes and concentrations of OT are low. Here we report a chemical and biological validation for a commercially available enzyme immunoassay for OT in unextracted plasma. In addition, comparisons of OT were made across species to allow comparison of the monogamous prairie vole (Microtus ochrogaster (Wagner, 1842)) to the polygynous Sprague Dawley rat. These species were chosen because OT plays a role in the formation of social bonds and we predicted that the highly social prairie vole would have higher plasma OT than the less social rat. Results of this comparison confirmed our hypothesis. Further, OT was significantly higher in females than in males in both species. Our results indicate that this enzyme immunoassay can be used to assay plasma OT in rodents and that the predicted correlations exist between plasma OT and gender as well as species-typical social behavior.
In June 2020, the National Academies of Sciences, Engineering, and Medicine hosted a virtual workshop focused on integrating the science of aging and environmental health research. The concurrent ...COVID-19 pandemic and national attention on racism exposed shortcomings in the environmental research field's conceptualization and methodological use of race, which have subsequently hindered the ability of research to address racial health disparities. By the workshop's conclusion, the authors deduced that the utility of environmental aging biomarkers-aging biomarkers shown to be specifically influenced by environmental exposures-would be greatly diminished if these biomarkers are developed absent of considerations of broader societal factors-like structural racism-that impinge on racial health equity.
The authors reached a post-workshop consensus recommendation: To advance racial health equity, a "compound" exposome approach should be widely adopted in environmental aging biomarker research. We present this recommendation here.
The authors believe that without explicit considerations of racial health equity, people in most need of the benefits afforded by a better understanding of the relationships between exposures and aging will be the least likely to receive them because biomarkers may not encompass cumulative impacts from their unique social and environmental stressors. Employing an exposome approach that allows for more comprehensive exposure-disease pathway characterization across broad domains, including the social exposome and neighborhood factors, is the first step. Exposome-centered study designs must then be supported with efforts aimed at increasing the recruitment and retention of racially diverse study populations and researchers and further "compounded" with strategies directed at improving the use and interpretation of race throughout the publication and dissemination process. This compound exposome approach maximizes the ability of our science to identify environmental aging biomarkers that explicate racial disparities in health and best positions the environmental research community to contribute to the elimination of racial health disparities. https://doi.org/10.1289/EHP8392.
Estrogens are neuroprotective and, thus, potentially useful for the therapy of Alzheimer's disease; however, clinical use of hormone therapy remains controversial due to adverse peripheral effects. ...The goal of this study was to investigate the benefits of treatment with 10β,17β-dihydroxyestra-1,4-dien-3-one (DHED), a brain-selective prodrug of 17β-estradiol, in comparison with the parent hormone using APPswe/PS1dE9 double transgenic mice to model the pathology of the disease. Ovariectomized and intact females were continuously treated with vehicle, 17β-estradiol, or DHED via subcutaneous osmotic pumps from 6 to 8months of age. We confirmed that this prolonged treatment with DHED did not stimulate uterine tissue, whereas 17β-estradiol treatment increased uterine weight. Amyloid precursor protein decreased in both treatment groups of intact, but not in ovariectomized double transgenic females in which ovariectomy already decreased the expression of this protein significantly. However, reduced brain amyloid-β peptide levels could be observed for both treatments. Consequently, double-transgenic ovariectomized and intact mice had higher cognitive performance compared to untreated control animals in response to both estradiol and DHED administrations. Overall, the tested brain-selective 17β-estradiol prodrug proved to be an effective early-stage intervention in an Alzheimer's disease-relevant mouse model without showing systemic impact and, thus, warrants further evaluation as a potential therapeutic candidate.
•.Treatment of AD-dtg mice with a brain-selective 17β-estradiol (DHED) decreased APP•DHED treatment reduced brain amyloid-β peptide levels•DHED-treated AD-dtg mice had improved cognitive performance•DHED treatment faithfully replicated positive effects observed for 17β-estradiol•DHED did not stimulate uterine tissue, whereas 17β-estradiol treatment did.
Microbiomes have emerged as a key component essential for maintaining the health of an organism. Additionally, the roles of microbiomes are multifaceted, some unique to specific body areas and organs ...while others, particularly the gut microbiome, having broader effects on the entire organism. Comparative literature is emerging that compares microbiomes across mammals and birds. Domestic poultry have been the most extensively studied relative to their role in production agriculture. These data have provided a great deal of information about the effects of diet and nutritional requirements relative to the gut microbiome, productivity, and resilience to diseases. Conversely, limited research has been conducted on wild birds, despite them inhabiting a broad array of ecological niches and environments, providing a rich diversity in their adaptations to different habitats. Migratory birds and raptors are of particular interest. Migratory birds encounter a range of ecosystems and provide a link between allopatric populations. Raptors occupy high positions in the food chain, with potential exposure to biomagnification of environmental contaminants and pathogens. This review overviews our current understanding of the structure and function of avian microbiomes as related to avian health and reproduction in domestic and wild birds, highlighting knowledge gaps in need of further investigation for more effective conservation of rapidly declining avian populations. Lay summary Birds are among the most endangered organisms on the planet, vulnerable to many environmental challenges, including disease, loss of habitat, shortage of food resources, and climate-related change. They need to adapt to these challenges to survive and flourish. While the links between the gut microbiome, diet, resistance to infection, and behavior have been well studied in humans, laboratory animals, and domestic or captive birds, comparatively little is known about these associations in wildlife, where diet is expected to be more varied and seasonal. This is especially true for wild bird species. We review the information that is available on the microbiomes of both domestic and wild birds, highlighting knowledge gaps in our understanding of the health and reproduction of wild birds, toward furthering their conservation.
We recently reported that air cell administration of penta-brominated diphenyl ether (penta-BDE; DE-71) evokes biochemical and immunologic effects in chicken (
Gallus gallus) embryos at very low ...doses, and impairs pipping (i.e., stage immediately prior to hatching) and hatching success at 1.8
μg
g
−1 egg (actual dose absorbed) in American kestrels (
Falco sparverius). In the present study, absorption of polybrominated diphenyl ether (PBDE) congeners was measured following air cell administration of a penta-BDE mixture (11.1
μg DE-71
g
−1 egg) or an octa-brominated diphenyl ether mixture (octa-BDE; DE-79; 15.4
μg DE-79
g
−1 egg). Uptake of PBDE congeners was measured at 24
h post-injection, midway through incubation, and at pipping in chicken, mallard (
Anas platyrhynchos), and American kestrel egg contents, and at the end of incubation in black-crowned night-heron (
Nycticorax nycticorax) egg contents. Absorption of penta-BDE and octa-BDE from the air cell into egg contents occurred throughout incubation; at pipping, up to 29.6% of penta-BDE was absorbed, but only 1.40–6.48% of octa-BDE was absorbed. Higher brominated congeners appeared to be absorbed more slowly than lower brominated congeners, and uptake rate was inversely proportional to the log
K
ow of predominant BDE congeners. Six congeners or co-eluting pairs of congeners were detected in penta-BDE-treated eggs that were not found in the dosing solution suggesting debromination in the developing embryo, extraembryonic membranes, and possibly even in the air cell membrane. This study demonstrates the importance of determining the fraction of xenobiotic absorbed into the egg following air cell administration for estimation of the lowest-observed-effect level.
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