• The low maturation rate of oocytes is an important reason for female infertility and failure of assisted pregnancy. (cambridge.org)
  • The oocyte must maintain arrest at the diplotene stage until meiotic resumption occurs. (biomedcentral.com)
  • In addition, we determined that oocytes surrounded by their follicular cells expressing EGFR-Grb7 exhibit normal meiotic resumption. (bvsalud.org)
  • This study may be an important supplement for the mechanism of oocyte meiotic resumption and provide new diagnostic targets and treatment clues for infertility patients with oocyte maturation disorder. (cambridge.org)
  • Germinal vesicle breakdown (GVBD) occurs during oocyte meiotic maturation, a period when transcriptional processes are virtually inactive. (biomedcentral.com)
  • To characterize the effect of artificially increasing MIR21 on oocyte competence without inhibiting GVBD, a MIR21 mimic, scrambled microRNA negative control, or nuclease free water was micro-injected into denuded oocytes at 21 h of IVM. (biomedcentral.com)
  • Following germinal vesicle break down (GVBD) the oocyte is transcriptionally quiescent until fertilization and activation of the embryonic genome, occurring at the four-cell stage of development in the pig [ 9 ]. (biomedcentral.com)
  • The germinal vesicle breakdown (GVBD) is a landmark event of oocyte maturation. (cambridge.org)
  • In our previous studies, we found that zona pellucida 3 (ZP3) was strongly concentrated in the nuclear region of germinal vesicle (GV) oocytes and interacted with aryl hydrocarbon receptor-interacting protein-like 1 (AIPL1) and lamin A to promote GVBD. (cambridge.org)
  • cRNA microinjection of full-length or truncated MAD2L1BP uncovered their discordant roles in driving the extrusion of polar body 1 (PB1) in mouse oocytes. (bvsalud.org)
  • It was found that FIGNL1, a member of MTSPs, was predominantly expressed in mouse oocytes and distributed at the spindle poles during meiosis in the present study. (cambridge.org)
  • Although assisted reproductive techniques (ART) have helped to solve many infertility problems, they cause changes in the expression of miRNA and genes in oocytes and preimplantation embryos, and the effect of these changes on the future of offspring is unknown, and has caused concerns. (bvsalud.org)
  • This unusual maturation unravels atypical spindle formation but is rescued by inhibiting integrin ß1 or Grb7 binding to the EGFR. (bvsalud.org)
  • These oocytes are protected from abnormal meiotic spindle formation through the recruitment of O-GlcNAcylated Grb7, and OGT (O-GlcNAc transferase), the enzyme responsible for O-GlcNAcylation processes, in the integrin ß1-EGFR complex. (bvsalud.org)
  • Furthermore, an O-GlcNAcylation increase (by inhibition of O-GlcNAcase), the glycosidase that removes O-GlcNAc moieties, or decrease (by inhibition of OGT) amplifies oocyte spindle defects when follicular cells are absent highlighting a control of the meiotic spindle by the OGT-O-GlcNAcase duo. (bvsalud.org)
  • The spindle assembly checkpoint (SAC) is an intricate surveillance mechanism that ensures accurate segregation of chromosomes throughout cell cycles. (bvsalud.org)
  • Inhibition of nuclear meiotic maturation via IBMX significantly increased MIR21 and decreased its target, PDCD4. (biomedcentral.com)
  • SECM technique may be a valuable tool for accurately assessing the quality of embryos and thereby contribute to improving outcomes associated with assisted reproduction, including human in vitro fertilization. (bioone.org)
  • These protease-induced decreases in IGFBP-4 and -5 likely cause increased levels of bioavailable (or free) IGFs that stimulate steroidogenesis and mitogenesis in developing dominant follicles, which ultimately prepare the follicle(s) and oocyte(s) for successful ovulation and fertilization. (bioone.org)
  • Oocyte arrest at the diplotene stage is maintained in part through the activity of phosphodiesterase enzymes that catalyze the hydrolysis of cyclic adenosine monophosphate (cAMP) into AMP [ 1 , 2 ]. (biomedcentral.com)
  • Human oocyte maturation arrest represents one of the severe conditions for female patients with primary infertility. (bvsalud.org)
  • Once the kinetochores of chromosomes are correctly attached to bipolar spindles and the SAC is satisfied, the MAD2L1BP, best known as p31comet, binds mitosis arrest deficient 2 (MAD2) and recruits the AAA+-ATPase TRIP13 to disassemble the mitotic checkpoint complex (MCC), leading to the cell-cycle progression. (bvsalud.org)
  • In this study, by whole-exome sequencing (WES), we identified homozygous and compound heterozygous MAD2L1BP variants in three families with female patients diagnosed with primary infertility owing to oocyte metaphase I (MI) arrest. (bvsalud.org)
  • Together, our studies identified and characterized novel biallelic variants in MAD2L1BP responsible for human oocyte maturation arrest at MI, and thus prompted new therapeutic avenues for curing female primary infertility. (bvsalud.org)
  • Xenopus oocytes are encompassed by a layer of follicular cells that contribute to oocyte growth and meiosis in relation to oocyte maturation. (bvsalud.org)
  • We found that oocytes deprotected from their surrounding layer of follicular cells and expressing the epidermal growth factor (EGF) receptor (EGFR) and the Grb7 adaptor undergo accelerated prophase I to metaphase II meiosis progression upon stimulation by EGF. (bvsalud.org)
  • In summary, our study provides further insight into the role of the follicular cell layer in oocyte meiosis progression. (bvsalud.org)
  • AIPL1 was also proved to accumulate in the GV region of oocytes, and ZP3 deletion can significantly inhibit the aggregation of AIPL1 in the nuclear region. (cambridge.org)
  • Oocytes were collected from aspirated porcine tertiary follicles. (biomedcentral.com)
  • However, the effects of the interaction between follicular cells and the oocyte surface on meiotic processes are unclear. (bvsalud.org)
  • MicroRNAs (miRNAs) are small non-encoding RNAs that actively regulate biological and physiological processes, and play an important role in regulating gene expression in all cells, especially in most animal cells, including oocytes and embryos. (bvsalud.org)
  • Maturation of the mammalian oocyte is a complex process involving internal checkpoints and bidirectional communication with the surrounding cumulus cells. (biomedcentral.com)
  • The inability to transcribe mRNA during this stage of development and the probable necessity for post-transcriptional gene regulation (PTGR) suggests an important role for non-coding RNA in the maturing oocyte. (biomedcentral.com)
  • This study was conducted to evaluate in vivo and in vitro development of in vitro-matured equine oocytes fertilized by intracytoplasmic sperm injection. (bioone.org)
  • In vivo development was assessed after transfer of injected oocytes to the oviducts of recipient mares. (bioone.org)
  • The expression of miRNAs at the right time and place is crucial for the oocyte's maturation and the embryo's subsequent development. (bvsalud.org)
  • Understanding the biological functions of miRNAs in frozen maturated oocytes may provide a better understanding of embryonic development and a comparison of fertility conservation in female mammals. (bvsalud.org)
  • Relative abundance of mature MIR21 was quantified at 0, 8, 16, 24, 32, and 42 h of in vitro (IVM) with or without treatment with 3-isobutyl-1-methylxanthine (IBMX). (biomedcentral.com)
  • Of particular interest is understanding the role of non-coding RNA in regulating meiotic checkpoints in the oocyte, particularly that of microRNA-21 (MIR21). (biomedcentral.com)
  • Our results indicate MIR21 is active and important during meiotic maturation of the oocyte. (biomedcentral.com)
  • This RFA, Genetics and Physiology of Human Oocytes, is related to the priority area of family planning. (nih.gov)
  • BACKGROUND The overall goal of this RFA is to stimulate and support research on the gain of knowledge of genetic and physiological regulatory mechanisms in human oocytes. (nih.gov)
  • and there are dramatic new technological advances that can be applied to human oocytes. (nih.gov)
  • Beneficiaries of this initiative will be those who are interested in the various problems represented by the needs given above, such as infertility, contraception, environmental, aging and disease effects upon female germ cells, birth defects, as well as the fundamental developmental biology of human oocytes. (nih.gov)
  • There is much evidence that substantial differences exist among the species for a number of experimental and observational parameters, such that increased knowledge about human oocytes must be obtained directly through experiments and observations on human oocytes. (nih.gov)
  • The breakdown of the germinal vesicle indicates a resumption of meiosis and the extrusion of the first polar body (1 PB) indicates completion of the first meiotic division in human oocytes. (edu.au)
  • 2023. Circulatory extracellular vesicle derived miR-195-5p promotes cellular apoptosis and suppresses cell proliferation in the buffalo endometrial primary cell culture. (tkdlabndri.in)
  • The released oocyte is surrounded by a thick specialised extracellular matrix, the zona pellucida , that in turn is covered in layers of cells, the granulosa layer . (edu.au)
  • An emerging approach for cancer treatment employs the use of extracellular vesicles (EVs), specifically exosomes and microvesicles, as delivery vehicles. (regenerativemedicine.net)
  • In this study, by whole-exome sequencing (WES), we identified homozygous and compound heterozygous MAD2L1BP variants in three families with female patients diagnosed with primary infertility owing to oocyte metaphase I (MI) arrest. (bvsalud.org)
  • Early oocytes are also classified as immature (germinal vesicle (GV) or metaphase I (MI) stage). (edu.au)
  • Complete in vitro oogenesis: retrospects and prospects [3] "In reality the vast majority of oocytes formed from primordial germ cells (PGCs) will undergo apoptosis, or other forms of cell death. (edu.au)
  • However, to recapitulate mammalian oogenesis and produce fertilizable oocytes in vitro is a complex process involving several different cell types, precise follicular cell-oocyte reciprocal interactions, a variety of nutrients and combinations of cytokines, and precise growth factors and hormones depending on the developmental stage. (edu.au)
  • The oocyte (eggs, ova, ovum) is arrested at an early stage of the first {{meiosis))(first meiotic) division as a primary oocyte (primordial follicle) within the ovary . (edu.au)
  • In the reproductive system, despite Gsα being associated with oocyte meiotic arrest in vitro, the exact role of Gsα in female fertility in vivo remains largely unknown. (edu.au)
  • meiosis in Gsα-deficient oocytes precociously resumed in only 43% of antral follicles from mutant mice, indicating that alteration of meiotic pause was not the key factor in infertility. (edu.au)
  • Hormone treatment successfully induced spermiation and ovulation in P. corroboree , but refinement of gamete induction and IVF techniques will be required before ART protocols can be used to routinely propagate this species. (biomedcentral.com)
  • Among anurans (frogs and toads), it has been known for several decades that exogenous gonadotropins, and gonadotropin-releasing hormones, can be used to induce both sperm release (spermiation) and oocyte release (ovulation) [ 9 - 12 ]. (biomedcentral.com)
  • Although poor oocyte quality accounts for most female fertility problems, little is known about how oocytes maintain cellular fitness, or why their quality eventually declines with age2. (bvsalud.org)
  • Human oocyte maturation arrest represents one of the severe conditions for female patients with primary infertility. (bvsalud.org)
  • Together, our studies identified and characterized novel biallelic variants in MAD2L1BP responsible for human oocyte maturation arrest at MI, and thus prompted new therapeutic avenues for curing female primary infertility. (bvsalud.org)
  • Here we show that conditional knockout (cKO) of Mtor in either primordial or growing oocytes caused infertility but differentially affected oocyte quality, granulosa cell fate, and follicular development. (edu.au)
  • The results of studies generated by this RFA are expected to substantially advance our knowledge base of the genetic and physiological mechanisms that regulate the developmental program of human oocyte maturation. (nih.gov)
  • Meanwhile, the Gsα knockout-induced decline in oocyte quality and low developmental potential was partially rescued by antioxidant supplementation. (edu.au)
  • Therefore, MTOR-dependent pathways in primordial or growing oocytes differentially affected downstream processes including follicular development, sex-specific identity of early granulosa cells, maintenance of oocyte genome integrity, oocyte gene expression, meiosis, and preimplantation developmental competence. (edu.au)
  • RESULTS: Oocytes from reproductively old mice were smaller than young counterparts in terms of GV area (446.42 ± 4.15 vs. 416.79 ± 5.24 µm2, p (bvsalud.org)
  • There were no differences in the morphokinetic parameters of oocyte maturation between oocytes from reproductively young and old mice with respect to time to germinal vesicle breakdown (GVBD) (1.03 ± 0.03 vs. 1.01 ± 0.04 h), polar body extrusion (PBE) (8.56 ± 0.11 vs. 8.52 ± 0.15 h), duration of meiosis I (7.58 ± 0.10 vs. 7.48 ± 0.11 h), and kinetics of cumulus expansion (0.093 ± 0.002 vs. 0.089 ± 0.003 µm/min). (bvsalud.org)
  • Oocyte-specific deletion of Gsα induces oxidative stress and deteriorates oocyte quality in mice [1] "The stimulatory heterotrimeric Gs protein alpha subunit (Gsα) is a ubiquitous guanine nucleotide-binding protein that regulates the intracellular cAMP signaling pathway and consequently participates in a wide range of biological events. (edu.au)
  • Here, we generated oocyte-specific Gsα knockout mice by using the Cre/LoxP system. (edu.au)
  • GV oocytes from mutant mice showed early-stage apoptosis. (edu.au)
  • Oocyte stage-specific effects of MTOR determine granulosa cell fate and oocyte quality in mice [2] "MTOR (mechanistic target of rapamycin) is a widely recognized integrator of signals and pathways key for cellular metabolism, proliferation, and differentiation. (edu.au)
  • cRNA microinjection of full-length or truncated MAD2L1BP uncovered their discordant roles in driving the extrusion of polar body 1 (PB1) in mouse oocytes. (bvsalud.org)
  • Furthermore, the patient's oocytes carrying the mutated MAD2L1BP resumed polar body extrusion (PBE) when rescued by microinjection of full-length MAD2L1BP cRNAs. (bvsalud.org)
  • The goal of this study was to use a physiologic aging mouse model, in which egg aneuploidy levels increase, to determine whether there are age-dependent differences in morphokinetic parameters of oocyte maturation. (bvsalud.org)
  • All morphokinetic parameters of oocyte maturation were similar between euploid and aneuploid eggs irrespective of age. (bvsalud.org)
  • Specifically, males and females are administered hormones to stimulate the production and release of gametes (spermatozoa and oocytes), which are then used to generate embryos via in vitro fertilisation (IVF), also referred to as artificial fertilisation (AF) [ 5 ]. (biomedcentral.com)
  • Yet, how healthy oocytes balance essential mitochondrial activity with the production of ROS is unknown. (bvsalud.org)
  • Here we show that oocytes evade ROS by remodelling the mitochondrial electron transport chain through elimination of complex I. Combining live-cell imaging and proteomics in human and Xenopus oocytes, we find that early oocytes exhibit greatly reduced levels of complex I. This is accompanied by a highly active mitochondrial unfolded protein response, which is indicative of an imbalanced electron transport chain. (bvsalud.org)
  • Furthermore, the level of ROS (reactive oxygen species) and the mitochondrial aggregation increased, and antioxidant glutathione (GSH) content, ATP level, mtDNA copy number, and mitochondrial membrane potential decreased in Gsα-deficient oocytes. (edu.au)
  • In response, there has been an increasing focus on the use of Assisted Reproductive Technologies (ART), including the administration of reproductive hormones to induce gamete release followed by in vitro fertilisation. (biomedcentral.com)
  • Elvan Böke investigates the mechanisms that preserve the viability of dormant oocytes. (bvsalud.org)
  • CONCLUSION: There is no association between age or ploidy and the morphokinetics of mouse oocyte in vitro maturation (IVM). (bvsalud.org)
  • reported in vitro procedures that appear to reproduce efficiently these conditions allowing for the production, completely in a dish, of a relatively large number of oocytes that are fertilizable and capable of giving rise to viable offspring in the mouse. (edu.au)