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Biochimica Et Biophysica Acta Dec 2012Oogenesis is a complex process regulated by a vast number of intra- and extra-ovarian factors. Oogonia, which originate from primordial germ cells, proliferate by... (Review)
Review
Oogenesis is a complex process regulated by a vast number of intra- and extra-ovarian factors. Oogonia, which originate from primordial germ cells, proliferate by mitosis and form primary oocytes that arrest at the prophase stage of the first meiotic division until they are fully-grown. Within primary oocytes, synthesis and accumulation of RNAs and proteins throughout oogenesis are essential for oocyte growth and maturation; and moreover, crucial for developing into a viable embryo after fertilization. Oocyte meiotic and developmental competence is gained in a gradual and sequential manner during folliculogenesis and is related to the fact that the oocyte grows in interaction with its companion somatic cells. Communication between oocyte and its surrounding granulosa cells is vital, both for oocyte development and for granulosa cells differentiation. Oocytes depend on differentiated cumulus cells, which provide them with nutrients and regulatory signals needed to promote oocyte nuclear and cytoplasmic maturation and consequently the acquisition of developmental competence.The purpose of this article is to summarize recent knowledge on the molecular aspects of oogenesis and oocyte maturation, and the crucial role of cumulus-cell interactions, highlighting the valuable contribution of experimental evidences obtained in animal models. This article is part of a Special Issue entitled: Molecular Genetics of Human Reproductive Failure.
Topics: Animals; Female; Humans; Oocytes; Oogenesis; Ovarian Follicle
PubMed: 22634430
DOI: 10.1016/j.bbadis.2012.05.013 -
Genes Oct 2022Various pathogenic factors can lead to oogenesis failure and seriously affect both female reproductive health and fertility. Genetic factors play an important role in... (Review)
Review
Various pathogenic factors can lead to oogenesis failure and seriously affect both female reproductive health and fertility. Genetic factors play an important role in folliculogenesis and oocyte maturation but still need to be clarified. Oocyte maturation is a well-organized complex process, regulated by a large number of genes. Pathogenic variants in these genes as well as aneuploidy, defects in mitochondrial genome, and other genetic and epigenetic factors can result in unexplained infertility, early pregnancy loss, and recurrent failures of IVF/ICSI programs due to poor ovarian response to stimulation, oocyte maturation arrest, poor gamete quality, fertilization failure, or early embryonic developmental arrest. In this paper, we review the main genes, as well as provide a description of the defects in the mitochondrial genome, associated with female infertility.
Topics: Pregnancy; Humans; Female; Fertilization in Vitro; Oogenesis; Oocytes; Infertility, Female; Embryonic Development
PubMed: 36360157
DOI: 10.3390/genes13111920 -
Physiological Reviews Oct 2023Mammalian eggs (oocytes) are formed during fetal life and establish associations with somatic cells to form primordial follicles that create a store of germ cells (the... (Review)
Review
Mammalian eggs (oocytes) are formed during fetal life and establish associations with somatic cells to form primordial follicles that create a store of germ cells (the primordial pool). The size of this pool is influenced by key events during the formation of germ cells and by factors that influence the subsequent activation of follicle growth. These regulatory pathways must ensure that the reserve of oocytes within primordial follicles in humans lasts for up to 50 years, yet only approximately 0.1% will ever be ovulated with the rest undergoing degeneration. This review outlines the mechanisms and regulatory pathways that govern the processes of oocyte and follicle formation and later growth, within the ovarian stroma, through to ovulation with particular reference to human oocytes/follicles. In addition, the effects of aging on female reproductive capacity through changes in oocyte number and quality are emphasized, with both the cellular mechanisms and clinical implications discussed. Finally, the details of current developments in culture systems that support all stages of follicle growth to generate mature oocytes in vitro and emerging prospects for making new oocytes from stem cells are outlined.
Topics: Animals; Humans; Female; Oocytes; Ovarian Follicle; Ovary; Oogenesis; Mammals; Aging
PubMed: 37171807
DOI: 10.1152/physrev.00032.2022 -
Fertility and Sterility May 2021Cryopreservation of ovarian tissue to preserve the fertility of girls and young women at high risk of sterility is now widely practiced. Pieces of cryopreserved ovarian... (Review)
Review
Cryopreservation of ovarian tissue to preserve the fertility of girls and young women at high risk of sterility is now widely practiced. Pieces of cryopreserved ovarian cortex can be thawed and autografted to restore fertility, but because of the risks of reintroduction of the cancer, transplantation may not be possible for girls and women with blood-borne leukemias or cancers with a high risk of ovarian metastasis. Cryopreserved ovarian tissue contains mainly primordial follicles but also provides access to immature oocytes from small antral follicles, which may be matured in vitro to provide an additional source of mature oocytes. So in cases in which transplantation is contraindicated, fertility restoration could be safely achieved in the laboratory either by in vitro maturation (IVM) of oocytes aspirated from growing follicles or by the complete in vitro growth (IVG) and maturation (IVM) of primordial follicles to produce fertile metaphase II (MII) oocytes. The development of IVM and IVG methods to support all stages of oocytes available within ovarian tissue will maximize the potential for all patients undergoing fertility preservation.
Topics: Cryopreservation; Female; Fertility Preservation; Humans; In Vitro Oocyte Maturation Techniques; Oocytes; Oogenesis; Ovarian Follicle
PubMed: 33823993
DOI: 10.1016/j.fertnstert.2021.03.004 -
International Journal of Molecular... May 2023The quality and maturation of an oocyte not only play decisive roles in fertilization and embryo success, but also have long-term impacts on the later growth and... (Review)
Review
The quality and maturation of an oocyte not only play decisive roles in fertilization and embryo success, but also have long-term impacts on the later growth and development of the fetus. Female fertility declines with age, reflecting a decline in oocyte quantity. However, the meiosis of oocytes involves a complex and orderly regulatory process whose mechanisms have not yet been fully elucidated. This review therefore mainly focuses on the regulation mechanism of oocyte maturation, including folliculogenesis, oogenesis, and the interactions between granulosa cells and oocytes, plus in vitro technology and nuclear/cytoplasm maturation in oocytes. Additionally, we have reviewed advances made in the single-cell mRNA sequencing technology related to oocyte maturation in order to improve our understanding of the mechanism of oocyte maturation and to provide a theoretical basis for subsequent research into oocyte maturation.
Topics: Animals; Female; Oogenesis; Oocytes; Mammals; Meiosis; Granulosa Cells
PubMed: 37240406
DOI: 10.3390/ijms24109059 -
Nature Communications Aug 2022The combined use of transcriptome and translatome as indicators of gene expression profiles is usually more accurate than the use of transcriptomes alone, especially in...
The combined use of transcriptome and translatome as indicators of gene expression profiles is usually more accurate than the use of transcriptomes alone, especially in cell types governed by translational regulation, such as mammalian oocytes. Here, we developed a dual-omics methodology that includes both transcriptome and translatome sequencing (T&T-seq) of single-cell oocyte samples, and we used it to characterize the transcriptomes and translatomes during mouse and human oocyte maturation. T&T-seq analysis revealed distinct translational expression patterns between mouse and human oocytes and delineated a sequential gene expression regulation from the cytoplasm to the nucleus during human oocyte maturation. By these means, we also identified a functional role of OOSP2 inducing factor in human oocyte maturation, as human recombinant OOSP2 induced in vitro maturation of human oocytes, which was blocked by anti-OOSP2. Single-oocyte T&T-seq analyses further elucidated that OOSP2 induces specific signaling pathways, including small GTPases, through translational regulation.
Topics: Animals; Gene Expression Profiling; Gene Expression Regulation; Humans; Mammals; Mice; Oocytes; Oogenesis; Transcriptome
PubMed: 36042231
DOI: 10.1038/s41467-022-32791-2 -
Nature Nov 2016The female germ line undergoes a unique sequence of differentiation processes that confers totipotency to the egg. The reconstitution of these events in vitro using...
The female germ line undergoes a unique sequence of differentiation processes that confers totipotency to the egg. The reconstitution of these events in vitro using pluripotent stem cells is a key achievement in reproductive biology and regenerative medicine. Here we report successful reconstitution in vitro of the entire process of oogenesis from mouse pluripotent stem cells. Fully potent mature oocytes were generated in culture from embryonic stem cells and from induced pluripotent stem cells derived from both embryonic fibroblasts and adult tail tip fibroblasts. Moreover, pluripotent stem cell lines were re-derived from the eggs that were generated in vitro, thereby reconstituting the full female germline cycle in a dish. This culture system will provide a platform for elucidating the molecular mechanisms underlying totipotency and the production of oocytes of other mammalian species in culture.
Topics: Animals; Cell Line; Embryo, Mammalian; Female; Fertilization; In Vitro Techniques; Male; Meiosis; Mice; Mouse Embryonic Stem Cells; Oocytes; Oogenesis; Pluripotent Stem Cells; Transcriptome
PubMed: 27750280
DOI: 10.1038/nature20104 -
The Journal of Reproduction and... Feb 2020Oocyte quality is affected by many factors, among which the environment of growth and maturation seems to be crucial. Studies show that well balanced oocyte energy... (Review)
Review
Oocyte quality is affected by many factors, among which the environment of growth and maturation seems to be crucial. Studies show that well balanced oocyte energy metabolism has a significant impact on several elements of cytoplasmic and nuclear maturation as well as further embryo developmental competence. Therefore homeostasis between metabolism of glucose and fatty acids in the oocyte is being widely described nowadays. This review aims to discuss the follicular (in vivo) or maturation media (in vitro) environments with regard to glucose and fatty acid metabolism, as the main sources of the energy for the oocyte. A great emphasis is given on the balance between those two metabolic pathways and its further impact on female fertility.
Topics: Animals; Energy Metabolism; Fatty Acids; Female; Humans; In Vitro Oocyte Maturation Techniques; Lipid Metabolism; Oocytes; Oogenesis; Ovarian Follicle
PubMed: 31787727
DOI: 10.1262/jrd.2019-102 -
Molecular Cell Nov 2020Well-balanced and timed metabolism is essential for making a high-quality egg. However, the metabolic framework that supports oocyte development remains poorly...
Well-balanced and timed metabolism is essential for making a high-quality egg. However, the metabolic framework that supports oocyte development remains poorly understood. Here, we obtained the temporal metabolome profiles of mouse oocytes during in vivo maturation by isolating large number of cells at key stages. In parallel, quantitative proteomic analyses were conducted to bolster the metabolomic data, synergistically depicting the global metabolic patterns in oocytes. In particular, we discovered the metabolic features during meiotic maturation, such as the fall in polyunsaturated fatty acids (PUFAs) level and the active serine-glycine-one-carbon (SGOC) pathway. Using functional approaches, we further identified the key targets mediating the action of PUFA arachidonic acid (ARA) on meiotic maturation and demonstrated the control of epigenetic marks in maturing oocytes by SGOC network. Our data serve as a broad resource on the dynamics occurring in metabolome and proteome during oocyte maturation.
Topics: Animals; Epigenesis, Genetic; Fatty Acids, Unsaturated; Female; Meiosis; Metabolome; Mice; Mice, Inbred C57BL; Oocytes; Oogenesis; Proteome; Proteomics
PubMed: 33068521
DOI: 10.1016/j.molcel.2020.09.022 -
Reproductive Biology and Endocrinology... Feb 2022In vitro fertilization (IVF) is currently one of the most effective methods of infertility treatment. An alternative to commonly used ovarian hyperstimulation can become... (Review)
Review
In vitro fertilization (IVF) is currently one of the most effective methods of infertility treatment. An alternative to commonly used ovarian hyperstimulation can become extracorporeal maturation of oocytes (in vitro maturation; IVM). Fertilization and normal development of the embryo depends on the cytoplasmic, nuclear and genomic maturity of the oocyte. The microenvironment of the ovarian follicle and maternal signals, which mediate bidirectional communication between granulosa, cumulus and oocyte cells, influence the growth, maturation and acquisition of oocyte development capability. During oogenesis in mammals, the meiosis is inhibited in the oocyte at the prophase I of the meiotic division due to the high cAMP level. This level is maintained by the activity of C-type natriuretic peptide (CNP, NPPC) produced by granulosa cells. The CNP binds to the NPR2 receptor in cumulus cells and is responsible for the production of cyclic guanosine monophosphate (cGMP). The cGMP penetrating into the oocyte through gap junctions inhibits phosphodiesterase 3A (PDE3A), preventing cAMP hydrolysis responsible for low MPF activity. The LH surge during the reproductive cycle reduces the activity of the CNP/NPR2 complex, which results in a decrease in cGMP levels in cumulus cells and consequently in the oocyte. Reduced cGMP concentration unblocks the hydrolytic activity of PDE3A, which decreases cAMP level inside the oocyte. This leads to the activation of MPF and resumption of meiosis. The latest IVM methods called SPOM, NFSOM or CAPA IVM consist of two steps: prematuration and maturation itself. Taking into account the role of cAMP in inhibiting and then unblocking the maturation of oocytes, they have led to a significant progress in terms of the percentage of mature oocytes in vitro and the proportion of properly developed embryos in both animals and humans.
Topics: Animals; Cells, Cultured; Female; Humans; In Vitro Oocyte Maturation Techniques; Mammals; Meiosis; Oocytes; Oogenesis; Signal Transduction
PubMed: 35209923
DOI: 10.1186/s12958-022-00906-5