Biology of Reproduction最新文献

Granulosa and thecal layer cells play important roles in the post-hatching follicular growth in laying birds. To examine the biochemical processes of granulosa and thecal layers associated with follicular growth, the technique of data independent acquisition was used in this study to explore protein profiling in granulosa and thecal layers from growing follicles in laying ducks. We identified and quantitatively analyzed 8032 proteins in granulosa cells and 9552 proteins in thecal layer cells. Hierarchical clustering of the resulting profiles revealed differential changes of expression of proteins linked to cell metabolism, signaling, cell junction, especially in steroid synthesis, peroxisome proliferator-activated receptor, and gap junction signaling pathway at different stages of follicles. The highest expression of proteins related to gap junction and peroxisome proliferator-activated receptor signaling pathway occurred in granulosa cells of 3-6 mm or 6-8 mm follicles. In granulosa cells, decreases in the enzymes that catalyze the transformation of estrone into estradiol and proteins related to calcium transport and apoptosis occurred during follicular growth. As follicles grew, proteins related to androgens biosynthesis and involved in gap junction and peroxisome proliferator-activated receptor signaling pathway decreased in the thecal layer cells. Three main group functional clusters extracted from the protein-protein interaction network, were mainly responsible for apoptosis, steroid hormone biosynthesis, and the peroxisome proliferator-activated receptor signaling pathway. These proteomic data provide a holistic framework for understanding how diverse biochemical processes in granulosa cells and thecal layer cells are coordinated at the cellular level during follicular growth in laying birds.

Relationships between anti-Müllerian hormone (AMH) concentrations and subsequent ovarian stimulation outcomes have been demonstrated in several mammalian species, but comprehensive reports are lacking in felids. The objective of this study was to characterize relationships between AMH concentrations and responses to exogenous gonadotropin stimulation in cheetahs and domestic cats. Blood samples collected before stimulation were used to measure serum AMH concentrations, which were compared to post-stimulation outcomes, including counts of retrievable oocytes or ovulation sites, oocyte quality, embryonic cleavage after in vitro fertilization, and progestogen concentrations. Comparisons were also made between AMH concentrations and outcomes in domestic cats induced to ovulate by mechanical stimulation of the vagina and cervix (simulated coitus). Greater AMH concentrations were associated with greater ovulatory response, progestogen production, and embryonic cleavage success among gonadotropin-treated cheetahs, and with greater ovulatory response among gonadotropin-treated domestic cats. Associations were moderated by age, with AMH concentration generally a greater determinant of these outcomes in older animals. Using only AMH concentrations, domestic cats with high and low ovulatory responses to exogenous hormones could be distinguished. However, this marker was unrelated to ovulatory response in domestic cats after simulated coitus. These results demonstrate the potential for AMH concentrations to predict responses of cheetahs and domestic cats to ovarian stimulation treatment commonly used in assisted reproductive technologies. Associations between AMH concentrations and ovarian stimulation outcomes in these species might derive from relationships between AMH concentration and antral follicle count or oocyte/embryo cellular function, as reported in other mammals; however, this remains to be tested.

The number and distribution of follicles in each growth stage provides a reliable readout of ovarian health and function. Leveraging techniques for three-dimensional imaging of ovaries in toto has the potential to uncover total, accurate ovarian follicle counts. Due to the size and holistic nature of these images, counting oocytes is time consuming and difficult. The advent of machine-learning algorithms has allowed for the development of ultra-fast, automated methods to analyze microscopy images. In recent years, these pipelines have become more accessible to non-specialists. We used these tools to create OoCount, a high-throughput, open-source method for automatic oocyte segmentation and classification from fluorescent 3D microscopy images of whole mouse ovaries using a deep-learning convolutional neural network (CNN) based approach. We developed a fast tissue-clearing and imaging protocol to obtain 3D images of whole mount mouse ovaries. Fluorescently labeled oocytes from 3D images were manually annotated in Napari to develop a training dataset. This dataset was used to retrain StarDist using a CNN within DL4MicEverywhere to automatically label all oocytes in the ovary. In a second phase, we utilize Accelerated Pixel and Object Classification, a Napari plugin, to sort oocytes into growth stages. Here, we provide an end-to-end pipeline for producing high-quality 3D images of mouse ovaries and obtaining follicle counts and staging. We demonstrate how to customize OoCount to fit images produced in any lab. Using OoCount, we obtain accurate oocyte counts from each growth stage in the perinatal and adult ovary, improving our ability to study ovarian function and fertility.

Spermatogenesis is a complex process that can be disrupted by genetic and epigenetic changes, potentially leading to male infertility. Recent research has rapidly increased the number of protein coding mutations causally linked to impaired spermatogenesis in humans and mice. However, the role of non-coding mutations remains largely unexplored. As a case study to evaluate the effects of non-coding mutations on spermatogenesis, we first identified an evolutionarily conserved topologically associated domain (TAD) boundary near two genes with important roles in mammalian testis function: Dmrtb1 and Lrp8. We then used CRISPR-Cas9 to generate a mouse line where 26 kb of the boundary was removed including a strong and evolutionarily conserved CTCF binding site. ChIP-seq and Hi-C experiments confirmed the removal of the CTCF site and a resulting mild increase in the DNA-DNA interactions across the domain boundary. Mutant mice displayed significant changes in testis gene expression, higher frequency of histological abnormalities, a drop of 47-52% in efficiency of meiosis, a 15-18% reduction in efficiency of spermatogenesis, and consistently, a 12-28% decrease in daily sperm production compared to littermate controls. Despite these quantitative changes in testis function, mutant mice show no significant changes in fertility. This suggests that non-coding deletions affecting testis gene regulation may have smaller effects on fertility compared to coding mutations of the same genes. Our results demonstrate that disruption of a TAD boundary can have a negative impact on sperm production and highlight the importance of considering non-coding mutations in the analysis of patients with male infertility.

The decidual endometrial stromal cells play a critical role in the establishment of uterine receptivity and pregnancy in human. Our previous studies demonstrate that protein tyrosine phosphatase 2 SHP2 is highly expressed in decidualized cells and governs the decidualization progress. However, the role and mechanism of SHP2 in the function of decidual cells remain unclear. Here, we screened proteins interacting with SHP2 in decidual hTERT-immortalized human endometrial stromal cells (T-HESCs) and identified Hypoxia-inducible factor-1 (HIF-1) signaling pathway as a potential SHP2-mediated signaling pathway through proximity-dependent biotinylation (BioID) analysis. Immunoprecipitation (Co-IP) revealed an interaction between SHP2 and HIF-1α, which colocalized to the nucleus in decidual cells. Furthermore, the SHP2 expression correlated with the transcriptional activation of HIF-1α and its downstream genes Beta-enolase (Eno3), Pyruvate kinase 2 (Pkm2), Aldolase C (Aldoc), and Facilitative glucose transporter 1 (Glut1). Knockdown or inhibition of SHP2 significantly reduced the mRNA and protein levels of HIF-1α and its downstream genes, as well as lactate production in decidual cells. We also established a hypoxia model of T-HESCs and 293T cells and found that hypoxic treatment induced the expression of SHP2 and HIF-1α, which colocalized in the nucleus. SHP2 forced-expression rescued the inhibitory effects of SHP2 deficiency on HIF-1α expression and lactate production. Finally, SHP2 binds to the promoter regions of HIF-1α and its target genes (Eno3, Pkm2, Aldoc, and Glut1). Collectively, our results suggest that SHP2 influences the function of decidual cells by HIF-1α signaling and provide a novel function mechanism of decidual stromal cells.

Periodic increases in cytosolic calcium concentration (Ca2+ oscillations) during mammalian fertilization induce all the events collectively known as egg activation. The sperm-specific phospholipase C, PLC zeta 1 (PLCZ1) represents the "sperm factor" vital for initiating the persistent Ca2+ oscillations in mammals. Despite sequence conservation, the Ca2+ oscillation-inducing properties of the enzyme differ vastly among species, and this is particularly salient between mouse and rat PLCZ1, where the activities vary at least one order of magnitude in favor of the former. As previously shown, injecting wild-type (WT) rat Plcz1 mRNA into metaphase II (MII) mouse eggs induced delayed Ca2+ oscillations with low specific activity compared to the homologous mouse Plcz1 mRNA. We, therefore, sought to uncover the factor(s) diversifying these enzymes by swapping functional domains between species, creating chimeric PLCZ1s. When injected into mouse MII eggs, mouse Plcz1 mRNA with the whole- or part of the EF-hand domains swapped with the rat showed a substantial reduction in activity compared to WT. Consistently, the opposite exchange enhanced the rat's enzyme activity. EF-hand domains 1 and 2 seemed to underlie most differences, and mutations of the divergent amino acids within these domains, substitutions for Glu(m-30; r-29) and Gln(m-58; r-57), changed the activity of both species' PLCZ1s in opposite directions. Collectively, our findings support the view that differences in the sequences of EF-hand domains, especially in several of its charged residues, underpin the distinct PLCZ1 activities between these species, revealing the gametes and species' adaptability to optimize the fertilization signal and early development.

In vitro fertilization (IVF) is a widely used assisted reproductive technology to achieve a successful pregnancy. However, the acquisition of oxidative stress in embryo in vitro culture impairs its competence. Here, we demonstrated that a nuclear coding gene, methyltransferase-like protein 7A (METTL7A), improves the developmental potential of bovine embryos. We found that exogenous METTL7A modulates expression of genes involved in embryonic cell mitochondrial pathways and promotes trophectoderm development. Surprisingly, we discovered that METTL7A alleviates mitochondrial stress and DNA damage and promotes cell cycle progression during embryo cleavage. In summary, we have identified a novel mitochondria stress eliminating mechanism regulated by METTL7A that occurs during the acquisition of oxidative stress in embryo in vitro culture. This discovery lays the groundwork for the development of METTL7A as a promising therapeutic target for IVF embryo competence.

Optimal embryonic development depends upon cell-signaling molecules released by the maternal reproductive tract called embryokines. Identity of specific embryokines that enhance competence of the embryo for sustained survival is largely lacking. The current objective was to evaluate effects of three putative embryokines in cattle on embryonic development to the blastocyst stage. The molecules tested were vascular endothelial growth factor A (VEGFA), C-X-C motif chemokine ligand 12 (CXCL12), and interleukin-6 (IL6). Molecules were added from day 4 to 7.5 of culture at 50 ng/mL (VEGFA and CXCL12) or 100 ng/mL (IL6). Endpoints were development to the blastocyst stage, and transcript abundance for 94 specific genes involved in lineage commitment, epigenetic regulation, and other functions. Among the genes examined were eight whose transcript abundance have been related to embryo competence for survival after embryo transfer. None of the molecules increased the proportion of putative zygotes or cleaved embryos becoming blastocyst at day 7.5 of development. An embryo competence index based on a Bayesian multiple regression formula to weigh transcript abundance of the eight biomarker genes was not affected by treatment with VEGFA but was increased by both CXCL12 and IL6. Transcript abundance of five genes were modified by VEGFA, 19 by CXCL12 and 19 by IL6. A total of 11 genes were modified in a similar manner by CXCL12 and IL6. Most differentially-expressed genes for CXCL12 and IL6 were downregulated, suggesting that the embryokines may promote a less energetically-demanding metabolic state than would be the case in their absence.