Bovine oocyte maturation: acquisition of developmental competence

2020 ◽  
Vol 32 (2) ◽  
pp. 98
Author(s):  
Bernard A. J. Roelen
Keyword(s):  
Oocyte Maturation ◽  
Developmental Competence ◽  
Cell Contact ◽  
Intimate Contact ◽  
Homologous Chromosomes ◽  
Paracrine Signalling ◽  
Sister Chromatids ◽  
Direct Cell

Although millions of oocytes are formed during embryo and fetal development in the cow, only a small fraction of these will form a developmentally competent oocyte and be fertilised. Development to competence relies on an intimate contact between the oocyte and the surrounding somatic cells in ovarian follicles, via both direct cell–cell contact and paracrine signalling. An important aspect of oocyte maturation is the segregation of homologous chromosomes and subsequently sister chromatids to form a haploid oocyte. Furthermore, the cytoplasm needs to be prepared for the formation of pronuclei and nuclear reprogramming to form a totipotent zygote. Conditions such as high levels of fatty acids or oxidative stress constrain the developmental competence of oocytes, and a better insight into these processes may help improve in vitro and in vivo oocyte maturation success. In addition, identification of the developmentally competent oocyte is useful for the efficiency of (artificial) reproduction.

scholarly journals Maturation of human oocytes in vitro and their developmental competence

Reproduction ◽  
2001 ◽  
pp. 51-75 ◽  
Author(s):  
A Trounson ◽  
C Anderiesz ◽  
G Jones
Keyword(s):  
Embryo Development ◽  
Oocyte Maturation ◽  
Growth Phase ◽  
Developmental Competence ◽  
Minimum Size ◽  
Success Rates ◽  
Human Oocytes ◽  
Maturation In Vitro

Complete maturation of oocytes is essential for the developmental competence of embryos. Any interventions in the growth phase of the oocyte and the follicle in the ovary will affect oocyte maturation, fertilization and subsequent embryo development. Oocyte size is associated with maturation and embryo development in most species examined and this may indicate that a certain size is necessary to initiate the molecular cascade of normal nuclear and cytoplasmic maturation. The minimum size of follicle required for developmental competence in humans is 5-7 mm in diameter. Maturation in vitro can be accomplished in humans, but is associated with a loss of developmental competence unless the oocyte is near completion of its preovulatory growth phase. This loss of developmental competence is associated with the absence of specific proteins in oocytes cultured to metaphase II in vitro. The composition of culture medium used successfully for maturation of human oocytes is surprisingly similar to that originally developed for maturation of oocytes in follicle culture in vitro. The presence of follicle support cells in culture is necessary for the gonadotrophin-mediated response required to mature oocytes in vitro. Gonadotrophin concentration and the sequence of FSH and FSH-LH exposure may be important for human oocytes, particularly those not exposed to the gonadotrophin surge in vivo. More research is needed to describe the molecular and cellular events, the presence of checkpoints and the role of gene expression, translation and protein uptake on completing oocyte maturation in vitro and in vivo. In the meantime, there are very clear applications for maturing oocytes in human reproductive medicine and the success rates achieved in some of these special applications are clinically valuable.

scholarly journals Effects of in vitro maturation on gene expression in rhesus monkey oocytes

2008 ◽  
Vol 35 (2) ◽  
pp. 145-158 ◽  
Author(s):  
Young S. Lee ◽  
Keith E. Latham ◽  
Catherine A. VandeVoort
Keyword(s):  
Oocyte Maturation ◽  
Nonhuman Primates ◽  
Cdna Array ◽  
Cell Types ◽  
Cell Interactions ◽  
Developmental Competence ◽  
Great Promise ◽  
Success Rates

In vitro oocyte maturation (IVM) holds great promise as a tool for enhancing clinical treatment of infertility, enhancing availability of nonhuman primates for development of disease models, and facilitating endangered species preservation. However, IVM outcomes have remained significantly below the success rates obtained with in vivo matured (VVM) oocytes from humans and nonhuman primates. A cDNA array-based analysis is presented, comparing the transcriptomes of VVM oocytes with IVM oocytes. We observe a small set of just 59 mRNAs that are differentially expressed between the two cell types. These mRNAs are related to cellular homeostasis, cell-cell interactions including growth factor and hormone stimulation and cell adhesion, and other functions such as mRNA stability and translation. Additionally, we observe in IVM oocytes overexpression of PLAGL1 and MEST, two maternally imprinted genes, indicating a possible interruption or loss of correct epigenetic programming. These results indicate that, under certain IVM conditions, oocytes that are molecularly highly similar to VVM oocytes can be obtained; however, the interruption of normal oocyte-somatic cell interactions during the final hours of oocyte maturation may preclude the establishment of full developmental competence.

scholarly journals IL-15Rα chaperones IL-15 to stable dendritic cell membrane complexes that activate NK cells via trans presentation

2008 ◽  
Vol 205 (5) ◽  
pp. 1213-1225 ◽  
Author(s):  
Erwan Mortier ◽  
Tammy Woo ◽  
Rommel Advincula ◽  
Sara Gozalo ◽  
Averil Ma
Keyword(s):  
Nk Cells ◽  
Biosynthetic Pathway ◽  
Cell Activation ◽  
Nk Cell ◽  
Cell Contact ◽  
Rapid Responses ◽  
Direct Cell ◽  
Membrane Bound

Natural killer (NK) cells are innate immune effectors that mediate rapid responses to viral antigens. Interleukin (IL)-15 and its high affinity IL-15 receptor, IL-15Rα, support NK cell homeostasis in resting animals via a novel trans presentation mechanism. To better understand how IL-15 and IL-15Rα support NK cell activation during immune responses, we have used sensitive assays for detecting native IL-15 and IL-15Rα proteins and developed an assay for detecting complexes of these proteins. We find that IL-15 and IL-15Rα are preassembled in complexes within the endoplasmic reticulum/Golgi of stimulated dendritic cells (DCs) before being released from cells. IL-15Rα is required for IL-15 production by DCs, and IL-15 that emerges onto the cell surface of matured DCs does not bind to neighboring cells expressing IL-15Rα. We also find that soluble IL-15–IL-15Rα complexes are induced during inflammation, but membrane-bound IL-15–IL-15Rα complexes, rather than soluble complexes, support NK cell activation in vitro and in vivo. Finally, we provide in vivo evidence that expression of IL-15Rα specifically on DCs is critical for trans presenting IL-15 and activating NK cells. These studies define an unprecedented cytokine–receptor biosynthetic pathway in which IL-15Rα serves as a chaperone for IL-15, after which membrane-bound IL-15Rα–IL-15 complexes activate NK cells via direct cell–cell contact.

scholarly journals Role for cumulus cell-produced EGF-like ligands during primate oocyte maturation in vitro

2009 ◽  
Vol 296 (5) ◽  
pp. E1049-E1058 ◽  
Author(s):  
Jenna K. Nyholt de Prada ◽  
Young S. Lee ◽  
Keith E. Latham ◽  
Charles L. Chaffin ◽  
Catherine A. VandeVoort
Keyword(s):  
Rhesus Macaque ◽  
Oocyte Maturation ◽  
Egf Receptor ◽  
Cumulus Cell ◽  
Cumulus Cells ◽  
Developmental Competence ◽  
Lower Percentage ◽  
Egfr Activation

The developmental competence of in vitro-matured (IVM) rhesus macaque cumulus oocyte complexes (COCs) is deficient compared with in vivo-matured (IVM) oocytes. To improve oocyte quality and subsequent embryo development following IVM, culture conditions must be optimized. A series of experiments was undertaken to determine the role of epidermal growth factor (EGF) during IVM of rhesus macaque COCs. The addition of Tyrphostin AG-1478 (a selective inhibitor of the EGF receptor EGFR) to the IVM medium yielded fewer oocytes maturing to metaphase II of meiosis II (MII), decreased cumulus expansion, and a lower percentage of embryos that developed to the blastocyst stage compared with untreated IVM controls, indicating that EGFR activation is important for IVM maturation in the rhesus macaque. However, the addition of recombinant human EGF (r-hEGF) to the IVM medium did not enhance outcome. The expression of mRNAs encoding the EGF-like factors amphiregulin, epiregulin, and betacellulin in cumulus cells indicates that these factors produced by cumulus cells may be responsible for maximal EGFR activation during oocyte maturation, precluding any further effect of exogenous r-hEGF. Additionally, these results illustrate the potential futility of exogenous supplementation of IVM medium without prior knowledge of pathway activity.

scholarly journals Activation of contact-dependent antibacterial tRNase toxins by translation elongation factors

2017 ◽  
Vol 114 (10) ◽  
pp. E1951-E1957 ◽  
Author(s):  
Allison M. Jones ◽  
Fernando Garza-Sánchez ◽  
Jaime So ◽  
Christopher S. Hayes ◽  
David A. Low
Keyword(s):  
Coiled Coil ◽  
Elongation Factor ◽  
Nuclease Activity ◽  
Ternary Complexes ◽  
Cell Contact ◽  
Translation Elongation ◽  
Direct Cell ◽  
Dependent Growth

Contact-dependent growth inhibition (CDI) is a mechanism by which bacteria exchange toxins via direct cell-to-cell contact. CDI systems are distributed widely among Gram-negative pathogens and are thought to mediate interstrain competition. Here, we describetsfmutations that alter the coiled-coil domain of elongation factor Ts (EF-Ts) and confer resistance to the CdiA-CTEC869tRNase toxin from enterohemorrhagicEscherichia coliEC869. Although EF-Ts is required for toxicity in vivo, our results indicate that it is dispensable for tRNase activity in vitro. We find that CdiA-CTEC869binds to elongation factor Tu (EF-Tu) with high affinity and this interaction is critical for nuclease activity. Moreover, in vitro tRNase activity is GTP-dependent, suggesting that CdiA-CTEC869only cleaves tRNA in the context of translationally active GTP·EF-Tu·tRNA ternary complexes. We propose that EF-Ts promotes the formation of GTP·EF-Tu·tRNA ternary complexes, thereby accelerating substrate turnover for rapid depletion of target-cell tRNA.

Gene transcription and regulation of oocyte maturation

2004 ◽  
Vol 16 (2) ◽  
pp. 55 ◽  
Author(s):  
Karina F. Rodriguez ◽  
Charlotte E. Farin
Keyword(s):  
Oocyte Maturation ◽  
In Vitro Maturation ◽  
Transcriptional Control ◽  
Molecular Mechanisms ◽  
Developmental Competence ◽  
Developmental Potential ◽  
Oocyte Developmental Competence ◽  
Specific Factors

The developmental potential of an embryo is dependent on the developmental potential of the oocyte from which it originates. The process of oocyte maturation is critical for the efficient application of biotechnologies such as in vitro embryo production and mammalian cloning. However, the overall efficiency of in vitro maturation remains low because oocytes matured in vitro have a lower developmental competence than oocytes matured in vivo. Furthermore, oocytes that have been exposed to gonadotropins have greater developmental competence than oocytes matured in the absence of gonadotropins. By understanding the molecular mechanisms underlying gonadotropin-induced maturation, improvement in oocyte maturation technologies may be expected as procedures to manipulate specific factors involved in signalling for resumption of meiosis are identified. The present review will focus on transcriptional mechanisms underlying the maturation of mammalian oocytes in vitro, as well as on the acquisition of oocyte developmental competence. In addition, a working model for the transcriptional control of mammalian oocyte maturation is proposed.

Recent insights into oocyte - follicle cell interactions provide opportunities for the development of new approaches to in vitro maturation

2011 ◽  
Vol 23 (1) ◽  
pp. 23 ◽  
Author(s):  
Robert B. Gilchrist
Keyword(s):  
Oocyte Maturation ◽  
In Vitro Maturation ◽  
Egf Receptor ◽  
Cumulus Cell ◽  
Follicle Cell ◽  
Cell Interactions ◽  
Developmental Competence ◽  
New Approaches

The last 5–10 years of research in ovarian and oocyte biology has delivered some major new advances in knowledge of the molecular and cellular processes regulating oocyte maturation and oocyte developmental competence. These new insights include, among others: (1) the knowledge that oocytes regulate granulosa and cumulus cell differentiation, ovulation rate and fertility via the secretion of soluble paracrine growth factors; (2) new perspectives on the participation of cyclic nucleotides, phosphodiesterases and gap junctions in the regulation of oocyte meiotic arrest and resumption; and (3) the new appreciation of the mechanisms of LH-induced oocyte maturation and ovulation mediated by the follicular cascade of epidermal growth factor (EGF)-like peptides, the EGF receptor and their intracellular second messengers. These recent insights into oocyte–follicle cell interactions provide opportunities for the development of new approaches to oocyte in vitro maturation (IVM). Laboratory IVM methodologies have changed little over the past 20–30 years and IVM remains notably less efficient than hormone-stimulated IVF, limiting its wider application in reproductive medicine and animal breeding. The challenge for oocyte biologists and clinicians practicing IVM is to modernise clinical IVM systems to benefit from these new insights into oocyte–follicle cell interactions in vivo.

scholarly journals The pivotal role of glucose metabolism in determining oocyte developmental competence

Reproduction ◽  
2010 ◽  
Vol 139 (4) ◽  
pp. 685-695 ◽  
Author(s):  
Melanie L Sutton-McDowall ◽  
Robert B Gilchrist ◽  
Jeremy G Thompson
Keyword(s):  
Glucose Metabolism ◽  
Oocyte Maturation ◽  
Cell Signalling ◽  
Polyol Pathway ◽  
Pentose Phosphate ◽  
Developmental Competence ◽  
Nuclear Maturation ◽  
Relative Contribution

The environment that the cumulus oocyte complex (COC) is exposed to during eitherin vivoorin vitromaturation (IVM) can have profound effects on the success of fertilisation and subsequent embryo development. Glucose is a pivotal metabolite for the COC and is metabolised by glycolysis, the pentose phosphate pathway (PPP), the hexosamine biosynthesis pathway (HBP) and the polyol pathway. Over the course of oocyte maturation, a large proportion of total glucose is metabolised via the glycolytic pathway to provide substrates such as pyruvate for energy production. Glucose is also the substrate for many cellular functions during oocyte maturation, including regulation of nuclear maturation and redox state via the PPP and for the synthesis of substrates of extracellular matrices (cumulus expansion) andO-linked glycosylation (cell signalling) via the HBP. However, the oocyte is susceptible to glucose concentration-dependent perturbations in nuclear and cytoplasmic maturation, leading to poor embryonic development post-fertilisation. For example, glucose concentrations either too high or too low result in precocious resumption of nuclear maturation. This review will discuss the relevant pathways of glucose metabolism by COCs duringin vivomaturation and IVM, including the relative contribution of the somatic and gamete compartments of the COC to glucose metabolism. The consequences of exposing COCs to abnormal glucose concentrations will also be examined, either during IVM or by altered maternal environments, such as during hyperglycaemia induced by diabetes and obesity.

scholarly journals Jagged1-Notch1-deployed tumor perivascular niche promotes breast cancer stem cell phenotype through Zeb1

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Huimin Jiang ◽  
Chen Zhou ◽  
Zhen Zhang ◽  
Qiong Wang ◽  
Huimin Wei ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Antiangiogenic Therapy ◽  
Cell Phenotype ◽  
Cell Contact ◽  
Perivascular Niche ◽  
Cancer Aggressiveness ◽  
E Box ◽  
Direct Cell

Abstract Zinc finger E-box binding homeobox 1 (Zeb1) has been demonstrated to participate in the acquisition of the properties of cancer stem cells (CSCs). However, it is largely unknown how signals from the tumor microenvironment (TME) contribute to aberrant Zeb1 expression. Here, we show that Zeb1 depletion suppresses stemness, colonization and the phenotypic plasticity of breast cancer. Moreover, we demonstrate that, with direct cell-cell contact, TME-derived endothelial cells provide the Notch ligand Jagged1 (Jag1) to neighboring breast CSCs, leading to Notch1-dependent upregulation of Zeb1. In turn, ectopic Zeb1 in tumor cells increases VEGFA production and reciprocally induces endothelial Jag1 in a paracrine manner. Depletion of Zeb1 disrupts this positive feedback loop in the tumor perivascular niche, which eventually lessens tumor initiation and progression in vivo and in vitro. In this work, we highlight that targeting the angiocrine Jag1-Notch1-Zeb1-VEGFA loop decreases breast cancer aggressiveness and thus enhances the efficacy of antiangiogenic therapy.

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