Endocrine-disrupting chemicals are natural and synthetic compounds found ubiquitously in the environment that interfere with the hormonal-immune axis, potentially impacting human health and reproduction. Exposure to endocrine-disrupting chemicals has been associated with numerous health risks, such as neurodevelopmental disorders, metabolic syndrome, thyroid dysfunction, infertility, and cancers. Nevertheless, the current approach to establishing causality between these substances and disease outcomes has limitations. Epidemiological and experimental research on endocrine-disrupting chemicals faces challenges in accurately assessing chemical exposure and interpreting non-monotonic dose response curves. In addition, most studies have focused on single chemicals or simple mixtures, overlooking complex real-life exposures and mechanistic insights, in particular regarding endocrine-disrupting chemicals' impact on the immune system. The ENDOMIX project, funded by the EU's Horizon Health Program, addresses these challenges by integrating epidemiological, risk assessment, and immunotoxicology methodologies. This systemic approach comprises the triangulation of human cohort, in vitro, and in vivo data to determine the combined effects of chemical mixtures. The present review presents and discusses current literature regarding human reproduction in the context of immunotolerance and chemical disruption mode of action. It further underscores the ENDOMIX perspective to elucidate the impact of endocrine-disrupting chemicals on immune-reproductive health.

Summary Sentence

ENDOMIX integrates epidemiological, in vitro, and in vivo data to address life expanse exposure to chemical mixtures and their underlying mechanisms.

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In cattle, oviductal function is controlled by the ovarian sex-steroids estradiol and progesterone. Here, we tested the hypothesis that the exposure to contrasting sex-steroid milieus differentially impacts the oviductal fluid composition. Estrous cycles of non-lactating, multiparous Nelore cows were pre-synchronized and then synchronized with a protocol designed two induce ovulation of large or small follciles. Larger preovulatory follicle (day 0) and corpora lutea (day 4) and greater estradiol (day 0) and progesterone (day 4) concentrations were observed in the large follciles group. Four days after induced ovulation, oviductal fluid was collected post-mortem. Quantitative mass spectrometry was used to determine the concentration of amino acids, biogenic amines, acylcarnitines, phosphatidylcholines, lysophosphatidylcholines, sphingomyelins, hexoses, prostaglandins, and related compounds. Multivariate analyses (orthogonal projections to latent structures discriminant analysis) were conducted to compare the metabolomic signatures of oviductal fluids. Correlation network analysis was conducted to measure the strength and hierarchy of associations among metabolites. Of the 205 metabolites quantified, 171 were detected in at least 50% of the samples and were included in further data analysis. After orthogonal projections to latent structures discriminant analysis analysis, samples of the large follciles and small follciles were divided clearly into two non-overlapping clusters. Twenty metabolites had different or tended to have different concentrations in the oviductal fluid when comparing groups. Seven of these 20 analytes had greater concentrations in large follciles cows. Moreover, total sum of biogenic amines, phosphatidylcholines, and prostaglandins were higher in the small follciles group. The correlation network showed that the large follciles group metabolites' concentrations were highly intercorrelated, which was not observed in the small follciles group. We concluded that the periovulatory endocrine milieu regulates the composition of the oviductal fluid.

Summary Sentence

Size of the ovulatory follicle is associated with the composition of the oviductal fluid in beef cows.

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Isthmus is the region of the oviduct considered a reservoir for spermatozoa, where they are retained and released synchronously with ovulation. Integrins mediate this interaction, and it is suggested that they regulate the viability and capacitation of spermatozoa. Spermatozoa retained in the oviductal epithelial cells show specific characteristics: normal morphology, intact acrosome and plasma membrane, no DNA fragmentation, and low levels of intracellular Ca²⁺, and protein phosphorylation at Tyr. This work aimed to define spermatozoa's ability to adhere to an immobilized fibronectin matrix and its effects on their viability and capacitation. We found that guinea pig spermatozoa showed a high affinity for adhering to an immobilized fibronectin matrix but not to those made up of type 1 collagen or laminin. This interaction was mediated by integrins that recognize the RGD domain. Spermatozoa adhered to an immobilized fibronectin matrix were maintained in a state of low capacitation: low levels of intracellular concentration of Ca²⁺, protein phosphorylation in Tyr, and F-actin. Also, spermatozoa kept their plasma membrane and acrosome intact, flagellum beating and showed low activation of caspases 3/7. The spermatozoa adhered to the immobilized fibronectin matrix, gradually detached, forming rosettes and did not undergo a spontaneous acrosomal reaction but were capable of experiencing a progesterone-induced acrosomal reaction. In conclusion, the adhesion of spermatozoa to an immobilized fibronectin matrix alters the physiology of the spermatozoa, keeping them in a steady state of capacitation, increasing their viability in a similar way to what was reported for spermatozoa adhered to oviductal epithelial cells.

Summary Sentence

Guinea pig sperm can adhere to a matrix made of immobilized fibronectin. This interaction changes sperm physiology, keeping them in a steady state of capacitation, preventing the spontaneous acrosomal reaction and increasing their viability.

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Environmental hypoxia adversely impacts the reproduction of humans and animals. Previously, we showed that fetal hypoxia exposure led to granulosa cell (GC) autophagic cell death via the Foxo1/Pi3k/Akt pathway. However, the upstream regulatory mechanisms underlying GC dysfunction remain largely unexplored. Here, we tested the hypothesis that fetal hypoxia exposure altered gene expression programs in adult GCs and impaired ovarian function. We established a fetal hypoxia model in which pregnant mice were maintained in a high-plateau hypoxic environment from gestation day (E) 0–16.5 to study the impact of hypoxia exposure on the ovarian development and subsequent fertility of offspring. Compared with the unexposed control, fetal hypoxia impaired fertility by disordering ovarian function. Specifically, fetal hypoxia caused mitochondrial dysfunction, oxidant stress, and autophagy in GCs in the adult ovary. RNA sequencing analysis revealed that 437 genes were differentially expressed in the adult GCs of exposed animals. Western blotting results also revealed that fetal exposure induced high levels of hypoxia-inducible factor 1-alpha (Hif1a) expression in adult GCs. We then treated granulosa cells isolated from exposed mice with PX-478, a specific pharmacological inhibitor of Hif1a, and found that autophagy and apoptosis were effectively alleviated. Finally, by using a human ovarian granulosa-like tumor cell line (KGN) to simulate hypoxia in vitro, we showed that Hif1a regulated autophagic cell death in GCs through the Pi3k/Akt pathway. Together, these findings suggest that fetal hypoxia exposure induced persistent Hif1a expression, which impaired mitochondrial function and led to autophagic cell death in the GCs of the adult ovary.

Summary Sentence

Autophagy induced ovarian GC death in fetal hypoxic female offspring through the Hif1a pathway.

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Background: Recurrent spontaneous miscarriage is one of the complications during pregnancy. However, the pathogenesis of recurrent spontaneous miscarriage is far from fully elucidated.

Objective: Since the endocytic pathway is crucial for cellular homeostasis, our study aimed to explore the roles of endocytic recycling, especially EH domain containing 1, a member of the endocytic recycling compartment, in recurrent spontaneous miscarriage.

Study Design: We first investigated the expression of the endocytic pathway member EH domain containing 1 in villi from the normal and recurrent spontaneous miscarriage groups. Then, we performed ribonucleic acid sequencing and experiments in villi, HTR8 cells and BeWo cells to determine the mechanisms by which EH domain containing 1–induced recurrent spontaneous miscarriage. Finally, placenta–specific EH domain containing 1–overexpressing mice were generated to investigate the recurrent spontaneous miscarriage phenotype in vivo.

Results: EH domain containing 1 was expressed in extravillous trophoblasts and syncytiotrophoblast in the villi. Compared with the control group, recurrent spontaneous miscarriage patients expressed higher EH domain containing 1. A high level of EH domain containing 1 decreased proliferation, promoted apoptosis, and reduced the migration and invasion of HTR8 cells by activating the TGFβ receptor 1-SMAD2/3 signaling pathway. The TGFβ receptor 1 antagonist LY3200882 partially reversed the EH domain containing 1 overexpression-induced changes in the cell phenotype. Besides, a high level of EH domain containing 1 also induced abnormal syncytialization, which disturbed maternal–fetal material exchanges. In a mouse model, placenta-specific overexpression of EH domain containing 1 led to the failure of spiral artery remodeling, excessive syncytialization, and miscarriage.

Conclusions: Increased expression of EH domain containing 1 impaired the invasion of extravillous trophoblasts mediated by the TGFβ receptor 1-SMAD2/3 signaling pathway and induced abnormal syncytialization of syncytiotrophoblast, which is at least partially responsible for recurrent spontaneous miscarriage.

Summary Sentence: Increased EH domain containing 1 activates the TGFβ receptor 1-SMAD2/3 signaling pathway and impairs the invasion of extravillous trophoblasts, demonstrating endocytic cycling is important during placentation and may be a potential target in the treatment of recurrent spontaneous miscarriage.

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Gestation period in captive Yangtze finless porpoise (YFP) is a well-coordinated and dynamic process, involving both systemic and local alterations. The gut microbiota and its connection to fecal metabolites are crucial in supporting fetal development and ensuring maternal health during reproductive stages. This study evaluates changes in the gut microbiota and their correlation with fecal metabolites in captive YFPs during different reproductive stages. The results reveal that microbial community structure changed significantly during reproductive stages, while gut microbial diversity remained stable. The genus unclassified Peptostrptococcaceae, Corynebacterium, and norank KD4–96 were significantly greater in non-pregnancy (NP), Terrisporobacter was significantly greater in lactating (LL), and Clostridium was significantly higher in early-pregnancy (EP) compared to the other groups. The host fecal metabolome exhibited significant alterations during the reproductive stages. Indoxyl sulfate, octadecatrienoic acid, and methionyl-methionine were significantly higher in the NP; galactosylglycerol, chondroitin 6-sulfate, and lumichrome were significantly higher in the EP and mid-pregnancy (MP); and valylleucine and butyryl-l-carnitine were significantly higher in the LL. The altered metabolites were mostly concentrated in pathways associated with arachidonic acid metabolism (significantly altered in NP), leucine, valine, and isoleucine biosynthesis (significantly altered in EP and MP), and glycerophospholipid metabolism (significantly altered in LL compared to others stages). Additionally, we found a strong link between variations in the host metabolism and alterations in the fecal bacteria of captive YFP. In conclusion, this study provides detailed insights into host metabolic and fecal bacterial changes in captive YFP during reproduction stages, providing important knowledge for improving the reproductive management in the captive YFP.

Summary Sentence

The current study aims to evaluate changes in the gut microbiota and their correlation with fecal metabolites in captive YFPs during different reproductive stages by providing important knowledge for improving the reproductive management of captive YFPs.

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Trophoblast stem cells, derived from the trophectoderm of the blastocyst, are used as an in vitro model to reveal the mechanisms underlying placentation in mammals. In humans, suitable culture conditions for trophoblast stem cell derivation have recently been established. The established human trophoblast stem cells differentiate efficiently toward two trophoblast subtypes: syncytiotrophoblasts and extravillous trophoblasts. However, the efficiency of differentiation is lower in macaque trophoblast stem cells than in human trophoblast stem cells. Here, we demonstrate that the activation of Wnt signaling downregulated the expression of inhibitory G protein and induced trophoblastic lineage switching to the syncytiotrophoblast progenitor state. The treatment of macaque trophoblast stem cells with a GSK-3 inhibitor, CHIR99021, upregulated syncytiotrophoblast progenitor markers and enhanced proliferation. Under the Wnt signaling–activated conditions, macaque trophoblast stem cells effectively differentiated to syncytiotrophoblasts upon dibutyryl cyclic AMP (dbcAMP) and forskolin treatment. RNA-seq analyses revealed the downregulation of inhibitory G protein, which may make macaque trophoblast stem cells responsive to forskolin. Interestingly, this lineage switching appeared to be reversible as the macaque trophoblast stem cells lost responsiveness to forskolin upon the removal of CHIR99021. The ability to regulate the direction of macaque trophoblast stem cell differentiation would be advantageous in elucidating the mechanisms underlying placentation in non-human primates.

Summary Sentence

The activation of Wnt signaling in macaque trophoblast stem cell lines potentiated differentiation toward syncytiotrophoblast cell fate.

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This study aimed to understand the physiological mechanisms regulating parturition and to identify potential biomarkers to predict onset of birth. Additionally, we compared hormone profiles between cows with shorter and longer gestation lengths. Twenty-eight days before due date until 3d postpartum, cows (n = 18) were blood-sampled daily. Circulating concentrations were measured for progesterone and estradiol by RIA, testosterone, prostaglandin F2α metabolite, cortisol, pregnancy-specific protein B by enzyme-linked immunosorbent assay, and lactate concentrations by colorimetric assay. At end of gestation, progesterone decreased from d-14 to d-4 (from 3.6 to 1.4 ng/mL), most likely from rapid loss of placental progesterone production (64% of decline in 24 h). A second rapid decrease in progesterone to undetectable concentrations was observed from d-2 to parturition (from 1.4 to 0.1 ng/ml; most likely luteal origin) corresponding to increase in prostaglandin F2α metabolite from d-2 to parturition (249.7 to 2868.4 pg/mL). E2 and pregnancy-specific protein B increased ∼8-fold from ∼13d before parturition with acute rise in E2 but not pregnancy-specific protein B (45% vs. 13% in first 24 h). Testosterone decreased slightly during the same period. Cortisol and lactate increased only at calving. Comparison of cows with shorter vs. longer gestation, when data were normalized to parturition day, a difference was detected in circulating E2 and prostaglandin F2α metabolite patterns, but not progesterone and pregnancy-specific protein B. Thus, the first significant hormonal changes associated with parturition begin at d-14 with E2 and pregnancy-specific protein B as two clear biomarkers of impending parturition. Cows with shorter and longer gestation had hormonal differences indicative of identifiable earlier placental maturation.

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The accurate diagnosis of non-obstructive azoospermia and obstructive azoospermia is crucial for selecting appropriate clinical treatments. This study aimed to investigate the pivotal role of microRNAs in circulating plasma extracellular vesicles in distinguishing between nonobstructive azoospermia and obstructive azoospermia, as well as uncovering the signaling pathways involved in azoospermia pathogenesis. In this study, differential expression of extracellular vesicle miR-513c-5p and miR-202-5p was observed between non-obstructive azoospermia and obstructive azoospermia patients, while the selenocompound metabolism pathway could be affected in azoospermia through Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analysis. The predictive power of these microRNAs was evaluated using receiver characteristic operator–area under the curve analysis, demonstrating promising sensitivity, specificity, and area under the curve values. A binomial regression equation incorporating circulating plasma levels of extracellular vesicles miR-202-5p and miR-513c-5p along with follicle-stimulating hormone was calculated to provide a clinically applicable method for diagnosing non-obstructive azoospermia and obstructive azoospermia. This study presents a potentially non-invasive testing approach for distinguishing between non-obstructive azoospermia and obstructive azoospermia, offering a possibly valuable tool for clinical practice.

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Although meiosis plays an essential role for the survival of species in natural selection, the genetic diversity resulting from sexual reproduction impedes human-driven strategies to transmit the most suitable genomes for genetic improvement, forcing breeders to select diploid genomes generated after fertilization, that is, after the encounter of sperm and oocytes carrying unknown genomes. To determine whether genomic assessment could be used before fertilization, some androgenetic haploid morula-stage bovine embryos derived from individual sperm were biopsied for genomic evaluation and others used to reconstruct “semi-cloned” (SC) diploid zygotes by the intracytoplasmic injection into parthenogenetically activated oocytes, and the resulting embryos were transferred to surrogate females to obtain gestations. Compared to controls, in vitro development to the blastocyst stage was lower and fewer surrogates became pregnant from the transfer of SC embryos. However, fetometric measurements of organs and placental membranes of all SC conceptuses were similar to controls, suggesting a normal post-implantation development. Moreover, transcript amounts of imprinted genes IGF2, IGF2R, PHLDA2, SNRPN, and KCNQ1OT1 and methylation pattern of the KCNQ1 DMR were unaltered in SC conceptuses. Overall, this study shows that sperm can be replaced by genotyped haploid embryonic-derived cells to produce bovine embryos carrying a predetermined paternal genome and viable first trimester fetuses after transfer to female recipients.

Summary Sentence

Haploid morula-stage embryonic cells derived from a single sperm can be genotyped and injected into activated oocytes to reconstruct diploid zygotes that develop both in vitro into blastocysts and in vivo into viable post-implantation bovine conceptuses with predetermined paternal genomes.

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Dcaf17, also known as DDB1- and CUL4-associated factor 17, is a member of the DCAF family and acts as the receptor for the CRL4 ubiquitin E3 ligase complex. Several previous studies have reported that mutations in Dcaf17 cause Woodhouse–Sakati syndrome, which results in oligoasthenoteratozoospermia and male infertility. As a model to explore the role of Dcaf17 in the male reproductive system, we created Dcaf17-deficient male golden hamsters using CRISPR-Cas9 technology; the results of which demonstrate that deletion of Dcaf17 led to abnormal spermatogenesis and infertility. To uncover the underlying molecular mechanisms involved, we conducted single cell Ribonucleic Acid sequencing analysis to evaluate the effect of Dcaf17 deficiency on transcriptional levels in spermatogenic cells during various stages of spermatogenesis. These data emphasize the significant regulatory role played by Dcaf17 in early spermatogenic cells, with many biological processes being affected, including spermatogenesis and protein degradation. Dysregulation of genes associated with these functions ultimately leads to abnormalities. In summary, our findings highlight the critical function of Dcaf17 in spermatogenesis and clarify the specific stage at which Dcaf17 exerts its effects, while simultaneously providing a novel animal model for the study of Dcaf17.

Summary Sentence

Dcaf17, a gene conserved across mammalian species, is crucial for the progression of spermatogenesis. Insights from single cell Ribonucleic Acid sequencing reveal a primary role for Dcaf17 during the early stages of germ cell development.

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An increase in global infertility has coincided with the accumulation of microplastics (MPs) in the environment. This trend is particularly troubling because only 10% of male infertility cases can be attributed to identifiable causes, leaving a knowledge gap in our understanding of their underlying factors. To bridge this, it is important to explore the connection between the accumulation of MPs and the observed decline in male fertility. We assessed the presence of microplastics in epididymal sperm from bulls and used it as baseline concentrations for sperm exposure. MPs were detected in all epidydimal sperm (ES) samples, with a mean concentration of 0.37 µg mL^–1. Next, to investigate the effects of MPs on fertility, bovine sperm was exposed to three different concentrations of a mixture of 1.1, 0.5, and 0.3 µm polystyrene (PS) beads: (1) 0.7 µg mL^–1, blood concentration of PS in cows (bPS); (2) 0.37 µg mL^–1, based on the concentration of total MPs found in ES (esMP); and (3) 0.026 µg mL^–1, based on the concentration of PS found in ES (esPS). All sperm samples incubated with PS exhibited reduced motility compared with the control at 0.5 h. However, PS exposure did not affect acrosome integrity or induced oxidative stress. Embryos produced from sperm exposed to PS had reduced blastocyst rates, in addition to increased ROS formation and apoptosis. By employing physiological exposure, this research provided evidence of MPs in bovine epididymal sperm and demonstrated the detrimental effect of PS on sperm functionality.

Summary Sentence

Microplastics are found in bull epidydimal sperm and true-to-life exposure of sperm to Polystyrene microplastics affects sperm function, inducing embryonic oxidative stress and apoptosis.

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