Microarray analysis of bovine oocyte from distinct follicle sizes reveals gradual transcripts accumulation
Ontology highlight
ABSTRACT:
ORGANISM(S): Bos taurus
PROVIDER: GSE48283 | GEO | 2015/11/15
SECONDARY ACCESSION(S): PRJNA209868
REPOSITORIES: GEO
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Project description:Despite great improvements in assisted reproductive technology (ARTs), the success of in vitro embryo production remains relatively low. Most of the oocytes used to produce in vitro embryos are recovered from smaller follicles, forming a heterogeneous population that must be matured in vitro. Since the original in vitro maturation (IVM ) experiments (Heilbrunn et al. , 1939) the process by which the most competent oocytes are selected to produce blastocysts remains similar and is still based on morphological aspects of the oocyte cytoplasm and the number of layers and compaction of cumulus cells attached to the oocyte surface (Armstrong, 2001, Coticchio et al. , 2004, Krisher, 2003, Lonergan et al. , 2003). Ovaries from crossbred cows (Bos indicus x Bos taurus) were collected immediately after slaughter and transported to the laboratory in saline solution (0.9% NaCl) supplemented with penicillin G (100 IU/mL) and streptomycin sulfate (100 mg/mL) at 35-37C. The follicles were dissected from the ovarian cortex using scissors, scalpels and tweezers in TCM-199 medium supplemented with Hank’s salts and 10% fetal calf serum (FCS; GIBCO BRL) at 36C. Follicles were measured using a graduated eyepiece (OSM-4; Olympus) and then classified morphologically into two groups according to their diameter: 1.0-3.0 mm or ≥8.0 mm. The criteria used for follicle selection included the presence of extensive and fine vascularization and a shiny and translucent appearance. After follicular rupture, the presence of granulosa cells with a regular and healthy appearance and no free-floating particles in the follicular fluid were also used as selection criteria. Only COCs with a homogeneous granulated cytoplasm and at least three layers of compact of cumulus cells were used in the present study. The selected COCs were transferred to a 50 μL droplet of phosphate-buffered saline (PBS), and the cumulus cells were mechanically removed by repeated pipetting. After cumulus collection, they were transferred to a 0.2-mL tube and centrifuged twice for 2 min at 700 g. The supernatant was removed, and 2μL of RNAlater (Applied Biosystems, Foster City, CA, USA) was added to the pellet, which was then stored at -20C until RNA extraction. For each follicle size group, three replicas of pooled cumulus cells corresponding to 30 oocytes were stored for RNA extraction and subsequent microarray assays, and four independent replicates corresponding to 20 oocytes were stored for RNA extraction for subsequent qPCR assays. During oogenesis, the somatic cells that surround the oocyte proliferate and differentiate into cumulus cells (CCs), which are metabolically coupled to the oocyte, forming the cumulus-oocyte complexes (COCs) (van den Hurk and Zhao, 2005). The CCs remain in strong contact with the oocyte, maintained by cytoplasmic bridges called gap-junctions, as well as through justacrine and paracrine signaling networks (Albertini et al. , 2001, Gilchrist et al. , 2004, Tanghe et al. , 2002, Vozzi et al. , 2001, Webb et al. , 2002). This intense bidirectional communication between the CCs and the oocyte is maintained during all phases of folliculogenesis and is essential for the acquisition of oocyte competence that is required for blastocyst development (Assidi et al., 2008, Fair, 2003, Gilchrist et al., 2004). An informative model to access the level of oocyte competence that has been used by many research groups is follicle size (Donnison and Pfeffer, 2004, Franco et al. , 2013, Lequarre et al. , 2005, Mourot et al., 2006). In a previous study, we showed that oocytes obtained from follicles 1-3 mm in diameter are significantly less competent in producing blastocysts than oocytes obtained from follicles ≥8 mm in diameter (Franco et al., 2013). In the present study, we use the same model to compare the gene expression profile of more than 23,000 bovine transcripts between the CCs obtained from incompetent COCs (1-3 mm) and competent COCs (≥8 mm). We have found substantial differences in the expression of several gene clusters representing distinct metabolic pathways such as energy metabolism, cell signaling, cell cycle, DNA repair, meiosis, and inflammation.
2015-01-27 | E-GEOD-65269 | biostudies-arrayexpress
Project description:oocytes were collected from ovarys of 6 day old female mice. Targets from four biological replicates of each were generated and the expression profiles were determined using Affymetrix MOE430 A & B. Experiment Overall Design: 4 oocyte at primary follicle stage biological replicates were analyzed
2008-06-12 | E-GEOD-3291 | biostudies-arrayexpress
Project description:Posttranslational modification of proteins by N-linked glycosylation is crucial for many life processes. However, the exact contribution of N-glycosylation to mammalian female reproduction remains largely undefined. Here, DPAGT1, the enzyme that catalyzes the first step of protein N-glycosyation, is identified to be indispensable for oocyte development in mice. A recessive missense mutation (c. 497A>G; p. Asp166Gly) of Dpagt1 causes female subfertility without grossly affecting other functions. Mutant females ovulate fewer eggs owing to defects of follicular development beyond the late secondary stage. Oocytes ovulated by mutants carry a thin and fragile zona pellucida, and display poor developmental competence after fertilization in vitro. Moreover, completion of the first meiosis is accelerated in mutant oocytes, which is coincident with the elevation of aneuploidy. Mechanistically, transcriptomic analysis reveals the downregulation of a number of transcripts essential for oocyte meiotic progression and preimplantation development (e.g., Pttgt1, Esco2, Orc6, and Npm2) in mutant oocytes, which could account for the defects observed. Furthermore, conditional knockout (CKO) of Dpagt1 in oocytes recapitulates the phenotypes observed in Dpagt1 mutant females, and causes complete infertility. Taken together, these data indicate that protein N-glycosylation in oocytes is essential for female fertility in mammals by specific control of oocyte development.
2021-09-09 | PXD018531 | Pride
Project description:So far, the characteristics of a good quality egg have been elusive, similar to the nature of the physiological, cellular, and molecular cues leading to its production both in vivo and in vitro. Current understanding highlights a strong and complex interdependence between the follicular cells and the gamete. Secreted factors induce cellular responses in the follicular cells, and direct exchange of small molecules from the cumulus cells to the oocyte through gap junctions controls meiotic arrest. Studying the interconnection between the cumulus cells and the oocyte, we previously demonstrated that the somatic cells also contribute transcripts to the gamete. Here, we show that these transcripts can be visualized moving down the transzonal projections (TZPs) to the oocyte, and that a time course analysis revealed progressive RNA accumulation in the TZPs, indicating that RNA transfer occurs before the initiation of meiosis resumption under a timetable fitting with the acquisition of developmental competence. A comparison of the identity of the nascent transcripts trafficking in the TZPs, with those in the oocyte increasing in abundance during maturation, and that are present on the oocyte's polyribosomes, revealed transcripts common to all three fractions, suggesting the use of transferred transcripts for translation. Furthermore, the removal of potential RNA trafficking by stripping the cumulus cells caused a significant reduction in maturation rates, indicating the need for the cumulus cell RNA transfer to the oocyte. These results offer a new perspective to the determinants of oocyte quality and female fertility, as well as provide insight that may eventually be used to improve in vitro maturation conditions.
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Project description:The palmitoyl-proteome of bovine cumulus-oocyte complexes (COCs) cells was investigated by combining acyl-biotin exchange chemistry and quantitative mass spectrometry analysis.
2022-02-15 | PXD020540 | Pride
Project description:Thecal tissue forms a layer around the follicle just prior to antral stage and grows with the follicle (containing an oocyte) as it matures. The innermost component (theca interna) supplies hormones and other factors necessary to the growth and development of the granulosa and oocyte. Most follicles regress and die (become atretic) at the antral stage, and this process as well as development of the follicle are undoubtedly influenced by the theca. Transcriptional changes in ovarian theca interna at the global level were examined by microarray during atresia and development to improve our understanding of the mechanisms involved.
2014-05-20 | GSE49505 | GEO
Project description:MicroRNAs (miRNA) are important regulators of oocyte maturation, playing a key role in modulating gene expression both in a temporal- and spatial-specific manner. These small non-coding RNAs are involved in important processes during oocyte maturation, acting as messengers between the oocyte and its surrounding cumulus cells. Despite its significance, the bidirectional communication mechanism is still unknown. To test miRNA communication between oocyte and surrounding cumulus cells through the gap junctions the gap junctions were either blocked with carbenoxolone or not. MiRNA sequencing of oocytes at 1, 6, and 22 hours of in vitro maturation was then performed. Among the differentially expressed miRNAs, bta-miR-21-5p, a regulator of cumulus cell viability and oocyte maturation, was the only previously known miRNA. Furthermore, by labeling a bta-miR-21-5p mimic with FAM, crossing of this miRNA through the gap junctions within the cumulus-oocyte complex could be visualized and internalization in the oocyte was confirmed by RT-qPCR. In conclusion, this study provides, for the first time, evidence that miRNA communication within the bovine cumulus-oocyte complex is enabled through the gap junctional network.
2024-08-02 | GSE252748 | GEO
Project description:Thecal tissue forms a layer around the follicle just prior to antral stage and grows with the follicle (containing an oocyte) as it matures. The innermost component (theca interna) supplies hormones and other factors necessary to the growth and development of the granulosa and oocyte. Most follicles regress and die (become atretic) at the antral stage, and this process as well as development of the follicle are undoubtedly influenced by the theca. Transcriptional changes in ovarian theca interna at the global level were examined by microarray during atresia and development to improve our understanding of the mechanisms involved. Four groups of bovine ovarian follicles were selected for analysis . Follicle size, type and array number for each group are, small (3-5 mm) healthy rounded (n=5), healthy columnar (n=5), atretic(n=5) and large healthy (>9mm), (n=4). For each group, the RNA from the theca interna of a single follicle was used to hybridise an array.
2014-05-20 | E-GEOD-49505 | biostudies-arrayexpress
Project description:Mammalian follicle development is characterised by extensive changes in morphology, endocrine responsiveness, and function, providing the optimum environment for oocyte growth, development, and resumption of meiosis. In cattle, the first signs of transcription activation in the oocyte are observed in the secondary follicle, later than during mouse and human oogenesis. While many studies have generated extensive datasets characterising gene expression in bovine oocytes, they are mostly limited to the analysis of fully grown and matured oocytes. The aim of the present study was to apply single-cell RNA sequencing to interrogate the transcriptome of the growing bovine oocyte from the secondary follicle stage through to the mid-antral follicle stage. Single-cell RNA-seq libraries were generated from oocytes of known diameters (<60 to >120 um), and datasets were binned into non-overlapping size groups for downstream analysis. Combining the results of weighted gene co-expression network and Trendy analyses, and differently expressed genes (DEGs) between size groups, we identified a decrease in oxidative phosphorylation and an increase in maternal -genes and transcription regulators across the bovine oocyte growth phase. In addition, around 5,000 genes did not change in expression, revealing a cohort of stable genes. An interesting switch in gene expression profile was noted in oocytes greater than 100 um in diameter, when the expression of genes related to cytoplasmic activities was replaced by genes related to nuclear activities (e.g., chromosome segregation). The highest number of DEGs were detected in the comparison of oocytes 100-109 versus 110-119 um in diameter, revealing a profound change in the molecular profile of oocytes at the end of their growth phase. The current study provides a unique dataset of the key genes and pathways characteristic of each stage of oocyte development, contributing an important resource for a greater understanding of bovine oogenesis.
2024-04-11 | GSE249434 | GEO
Project description:Differences in follicle-stimulating hormone (FSH) ß-subunit N-glycosylation results in distinct FSH glycoforms. Hypoglycosylated FSH21 is more bioactive and abundant in reproductively young women, whereas fully glycosylated FSH24 shows lower bioactivity and a relative increase with age. To investigate if the coinciding shift in FSH glycoform abundance contributes to the age-dependent decline in oocyte quality, an encapsulated in vitro follicle growth system was utilized to examine the direct effects of FSH glycoforms on folliculogenesis and resulting oocyte quality. Long-term culture (10-12 days) with FSH21 (10 ng/ml) enhanced follicle growth, estradiol secretion, and oocyte quality compared to equivalent FSH24 treatment. FSH21 exhibited enhanced capacity to establish transzonal projections, gap junctions, and cell-to-cell communication within 24 hrs in culture. Transient inhibition of FSH21-mediated bidirectional communication abrogated the positive effects of FSH21 on follicle growth, estradiol secretion and oocyte quality. These findings indicate FSH21 promotes folliculogenesis and oocyte quality in vitro through increasing cell-to-cell communication early in folliculogenesis and that the shift in abundance from FSH21 to FSH24 with reproductive aging could contribute to the age-dependent decline in oocyte quality.
2023-07-15 | GSE236967 | GEO