Biology of Reproduction最新文献

One of the principal pathogens in recurrent implantation failure (RIF) is poor decidualization. Although various factors have been identified as involved in regulating decidualization, much remains unknown. Studies have shown that the decidualization process is accompanied by active glutamine/α-ketoglutarate (α-KG) metabolism, but the specific mechanisms warrant further investigation. Here, through RNA-Seq, we have discovered that α-KG may regulate decidualization via indoleamine 2,3-dioxygenase 1 (IDO1), one of the key enzymes involved in the conversion of tryptophan to kynurenine. Mechanistically, this process relies on the demethylation of H3K27me3 in the IDO1 promoter region, thereby regulating the IDO1-Kyn-Aryl hydrocarbon receptor (AhR) pathway. At the same time, RIF patients exhibit downregulated glutamine/α-KG/IDO1 metabolism in the endometrium compared with fertile women. In mouse models with disrupted glutamine/α- KG metabolism, supplementation with α-ketoglutarate or tryptophan promotes decidualization and enhances pregnancy rates. Consequently, this study underscores the pivotal role of the glutamine/α- KG /IDO1 metabolic axis in the prevention and treatment of implantation failure.

During oocyte growth, rRNAs are transcribed in nucleolus and participate in ribosome formation, but dynamic changes of rRNAs during oocyte maturation haven't yet been studied. Using RNA-FISH, we found rRNAs in germinal vesicle breakdown (GVBD) stage oocytes and a small number of oocytes at the pro-metaphase of the first meiosis stage still associate with chromosomes, and can be labeled with 5-Ethynyl Uridine (5-EU). In oocytes, rDNA transcription factor UBTF are present within nucleoli at germinal vesicle (GV) stage or near chromosomes at GVBD stage. However, RNA polymerase I can only be found at GV but not GVBD oocytes. In contrast, RNA helicase DDX3X doesn't colocalize with UBTF in GV oocytes but does colocalize with UBTF in GVBD oocytes. During oocyte maturation, the proportion of oocyte with DDX3X focus gradually decrease after GVBD. At GVBD stage, both UBTF and DDX3X are associated with rRNA condensates. When treating oocytes with DDX3X inhibitor RK-33, the decrease of 5-EU signals in oocytes will be delayed. Both treatment of RK-33 or microinjection of mutated human DDX3X cRNAs significantly reduce polar body extrusion rate and increase rate of spindle abnormalities in oocytes. Based on these findings, we hypothesize that rRNA accumulated during GV stage may entangle condensed chromosomes during GVBD and impairs chromosome segregation, and RNA helicases such as DDX3X are recruited to rRNA condensate to facilitate its clearance, thereby promoting proper chromosome segregation in oocytes. These data reveal a novel mechanism regulating chromosome segregation in oocytes.

Maternal effects on offspring development do not end at birth. Bioactive factors are transmitted from mothers to nursing offspring through colostrum, by a process known as lactocrine signaling. In pigs, naturally occurring lactocrine insufficiency, indicated by reduced serum immunoglobulin immunocrit (iCrit) ratios within 24-h of postnatal life, impaired uterine development and reduced adult fecundity. This effect was evaluated at postnatal day (PND) 14 with histology and transcriptomics on six pairs of littermates with high- vs. low-iCrit measured at PND 1. RNA-seq analysis identified 148 differentially expressed genes (DEGs) between groups (P<0.05) and eight DEGs were validated by qRT-PCR (P<0.05), including FOXA2, a gene with well-established expression in the uterine glandular epithelium (GE) across multiple mammalian species. Immunohistochemistry confirmed FOXA2 localization in the PND 14 pig uterus, and lactocrine deficiency reduced endometrial glandularity, supported by fewer GE cells/mm2 in low versus high iCrit gilts (P<0.05). Downregulated genes in uteri from low-iCrit gilts were associated with growth, differentiation, and secretion, whereas upregulated genes were enriched for immune processes, including complement activation and cytokine signaling. These findings suggest that inadequate colostrum-derived antibodies trigger uterine immune activation at PND 14, potentially impairing development and reducing adult uterine capacity. Highly expressed genes in PND 14 pig uterus were enriched for structural, developmental, and growth functions and included a subset of tissue-specific genes shared between pigs and humans. Integration of pig and human GTEx datasets identified conserved and species-specific uterine-biased genes, including DEG between high- and low-iCrit gilts, highlighting potential uterine biomarkers of early uterine development.

Hybridization is common among animals and plants, but often leads to sterility due to improper chromosome pairing. Some hybrids overcome sterility through modified gametogenesis, enabling clonal or hemiclonal reproduction. In water frog hybrids from the Pelophylax esculentus complex, hybridogenesis typically ensures hemiclonal reproduction. These hybrids inherit haploid chromosomal sets (n = 13) from both parental species, Pelophylax lessonae and Pelophylax ridibundus. During hybrid gametogenesis, one genome is eliminated while the other is clonally transmitted. We analyzed hybrid males and females from Central Europe, where hybrids coexist with P. lessonae and with both parental species, to assess gametogenic stability and whether the P. lessonae genome is consistently eliminated. Most hybrids followed canonical gametogenesis with premeiotic elimination of the P. lessonae genome and endoreplication of the P. ridibundus genome, yielding haploid P. ridibundus gametes. Nevertheless, gametogenesis was frequently altered in males but not in females. Some hybrid males had spermatocytes with 13 or 26 univalents, 26 bivalents, or tetravalents, indicating variability in genome elimination and endoreplication. Some males produced diploid or haploid spermatids with P. ridibundus and P. lessonae genomes. Comparative genome hybridization revealed that some males with altered gametogenesis carried unusual chromosomes with mixed R and L signals. Furthermore, rare triploid males showed substitutions of P. lessonae chromosomes to P. ridibundus chromosomes. Despite altered gametogenesis, they produced spermatocytes and haploid spermatids with P. lessonae chromosomes and two P. ridibundus chromosomes that escaped elimination. Overall, despite a generally consistent pattern of genome transmission, hybrid males exhibit frequent deviations from canonical hybridogenesis across populations.

Maestro (MRO) is a transcription factor that has a role in regulating gene expression. The MRO expression pattern was examined in a unique set of human granulosa cells (GCs) and follicles collected across the ovulatory period of a natural menstrual cycle. MRO mRNA was elevated (70-fold) in women during the early ovulatory phase (12h to ≤18h post hCG administration; LH analog) and remained elevated (35-fold) in the late ovulatory phase (>18h to ≤ 34h) when compared to the preovulatory state (before the LH surge). Immunohistochemistry of whole follicles from women demonstrated positive MRO signal in GCs during the early and late ovulatory phases. Employing a cultured human granulosa luteal cell (hGLCs) model, we further examined MRO regulation in human granulosa cells from IVF patients. Treating hGLCs in vitro with hCG elevated MRO expression by 22-fold at 6h, 48-fold at 12h, and then expression slightly decreased to 13-fold at 24h. Similarly, the strongest MRO protein expression was detected at 12h. Next, LH/hCG signaling pathways regulating MRO expression were investigated using inhibitors specific to each signaling pathway. Our data revealed that hCG regulated MRO expression through LH-dependent classical signaling pathways such as PKA, PKC, and PI3K, with MAPK partially regulating its expression. Moreover, the EGF and progesterone pathways, important in the periovulatory period, were found to be involved in MRO regulation. These data, taken together, demonstrate that MRO is poised to play a role in the coordination of periovulatory events through the EGF and progesterone signaling pathways.

The placenta plays a crucial role in transferring nutrients and oxygen between the dam and fetus during pregnancy. It is highly influenced by environmental conditions, especially stressors such as heat and nutritional deficiencies, which can significantly impact the fetus's long-term health and development. Cattle, especially dairy cows, commonly experience stress during late gestation, which can lead to changes in behavior and physiology, affecting both subsequent milk production and fetal development. Heat stress is one of the most common stressors experienced by mammals, and recent evidence suggests a role in the programming of the dam and fetus. This review explores different hypotheses of fetal programming, including the Barker hypothesis, which connects early-life malnutrition to metabolic diseases in adulthood, and the silver-spoon hypothesis, which highlights the long-term benefits of optimal prenatal conditions. Furthermore, we consider heat stress programming as it relates to the concept of developmental origins of health and diseases. The developmental origins of health and disease hypothesis suggests that epigenetic adaptations occur in fetal DNA as a response to environmental influences. The review also emphasizes the role of the mechanism associated with possible epigenetic effects in the placenta, mediating the effects of maternal stress on the fetus, impacting gene expression, placental structure, and nutrient transfer. Understanding these mechanisms is essential for enhancing dairy cattle management and minimizing the adverse effects of environmental stressors on animal health and productivity.

The objective was to quantify the effect of in vitro procedures on the epigenome and transcriptome of the embryonic disc (ED) and extra-embryonic membranes (EEM) of day 15 in vitro produced (IVP) conceptuses compared to their in vivo (IVV) counterparts. IVP embryos (n = 7) were cultured serum-free until transfer at day 7, while IVV embryos (n = 9) were conceived through artificial insemination. Animals were flushed at day 15 of gestation, and sections of the ED and EEM underwent DNA and RNA extraction for whole-genome bisulfite or RNA sequencing. Raw fastq files were aligned to the ARS-UCD1.3 bovine genome. Processed data were integrated through a multi-omics approach based on machine learning to determine the key ontological terms that characterize each embryonic tissue lineage according to their methylome and transcriptome, followed by overrepresentation analyses (adjusted P-value < 0.05) of differentially methylated genes (DMG), differentially expressed genes (DEG), or genes that were both differentially methylated and differentially expressed in the ED or EEM of IVP compared to IVV conceptuses. Results demonstrated that identified critical ontological terms for the ED, such as somitogenesis, mesoderm formation, and gastrulation, were enriched among hypermethylated DMG, down-regulated DEG, and genes hypermethylated in the promoter and inhibited in expression in the ED of IVP embryos. Genes hypermethylated in the promoter and inhibited in expression in the EEM of IVP conceptuses were involved in epigenetic regulation. In conclusion, in vitro procedures alter the development of main lineage tissues in the pre-implantation embryo, even after interaction with the maternal environment.

Infertility and post-partum reproductive diseases are significant challenges in cattle farming, with the maternal immune system's ability to recognize and tolerate the embryo being crucial for successful gestation. DNA methylation in hematopoietic cells may influence susceptibility to post-partum fertility issues, making the identification of epigenetic changes vital for sustainable animal production. This study aimed to characterize the methylome of immune cells in relation to fertility, potentially enabling early detection of subfertility. Using whole epigenome sequencing and enzymatic methyl-seq, we analyzed DNA methylation patterns in blood from twelve Holstein cows before the onset of any disease. Our findings revealed 216 990 differentially methylated cytosines (DMCs) between fertile and subfertile cows. Notably, three genes-Interferon tau-3 (IFNT3), KIAA0825, and RAS-Related Protein 2A-showed high significance in their differential methylation between fertile and subfertile cows. IFNT3, crucial for early embryonic development, had seven DMCs in its transcription start site (TSS) shores in subfertile cows. Additionally, the KLRA1 gene (Ly49), was identified as containing DMCs across all five genomic regions analyzed (TSS shores, exons, introns, downstream, and distal intergenic). Its widespread differential methylation highlights its potential impact on fertility. Key interleukin genes, including IL6, IL15, IL22, and IL36G, also showed multiple DMCs, reinforcing the role of the immune system in bovine fertility. These findings illustrate the potential control that immune cell epigenetics exert on cattle post-partum fertility. Additionally, this study suggests that the risk of developing subfertility could potentially be estimated with as few as 220 biomarkers, paving the way for enhanced animal health management and improved fertility treatments.

Mitochondrial function is fundamental to female reproductive physiology, supporting follicular development, oocyte maturation, and endometrial remodeling. Ferroptosis, an iron-dependent form of regulated cell death driven by lipid peroxidation, has recently emerged as a potential contributor to reproductive dysfunction under conditions of mitochondrial impairment and oxidative stress. This review examines how mitochondrial quality-control (MQC) mechanisms-including biogenesis, dynamics, iron handling, and redox regulation-modulate ferroptotic sensitivity across female reproductive tissues. We highlight cell-type-specific differences, ranging from ferroptosis-associated granulosa cell loss during follicular atresia to sublethal ferroptotic stress affecting oocyte competence and tightly restrained ferroptosis during decidualization and implantation. By integrating experimental and clinical evidence, we propose that mitochondrial regulation of ferroptosis acts as a context-dependent modulator of reproductive function rather than a uniform cell death pathway. Understanding this interplay provides new insight into ovarian aging, infertility, and uterine receptivity, with implications for reproductive medicine.

Developmental programming in dogs, although less studied than in other species, encompasses both nutritional and behavioural influences during gestation and early life. The most critical window corresponds to the first 120 days (pregnancy followed but the first two months of dog's life), considered the canine equivalent of the human "first 1000 days of life." Low birth weight, result from the intra-uterine growth, is one of the most documented examples of developmental programming in this species. Its consequences extend long beyond the neonatal period: while early effects include disproportionate head development and increased mortality during the first three weeks, long-term effects include a greater predisposition to overweight in adulthood. Gestational programming is modulated by the dam's diet, which can affect birth weight, neonatal and paediatric health, and particularly inflammatory status. However, the postnatal period provides opportunities to counteract prenatal influences: the risk of neonatal mortality in low-birth-weight puppies that achieve adequate early growth during the first two days of life becomes similar to that of normal-birth-weight littermates. Conversely, excessive growth during the first weeks of life is suspected to increase the likelihood of adult overweight, highlighting the need for precise management of neonatal and paediatric growth to ensure healthy adult trajectories. Early-life behavioural programming, through maternal behaviour and environmental exposures, is also essential in shaping dogs for their future societal roles. Overall, developmental programming appears to be a key determinant of lifelong physical and mental health in dogs.