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Horakova A, Konecna M, Anger M. Chromosome Division in Early Embryos-Is Everything under Control? And Is the Cell Size Important? Int J Mol Sci 2024; 25:2101. [PMID: 38396778 PMCID: PMC10889803 DOI: 10.3390/ijms25042101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Revised: 02/02/2024] [Accepted: 02/06/2024] [Indexed: 02/25/2024] Open
Abstract
Chromosome segregation in female germ cells and early embryonic blastomeres is known to be highly prone to errors. The resulting aneuploidy is therefore the most frequent cause of termination of early development and embryo loss in mammals. And in specific cases, when the aneuploidy is actually compatible with embryonic and fetal development, it leads to severe developmental disorders. The main surveillance mechanism, which is essential for the fidelity of chromosome segregation, is the Spindle Assembly Checkpoint (SAC). And although all eukaryotic cells carry genes required for SAC, it is not clear whether this pathway is active in all cell types, including blastomeres of early embryos. In this review, we will summarize and discuss the recent progress in our understanding of the mechanisms controlling chromosome segregation and how they might work in embryos and mammalian embryos in particular. Our conclusion from the current literature is that the early mammalian embryos show limited capabilities to react to chromosome segregation defects, which might, at least partially, explain the widespread problem of aneuploidy during the early development in mammals.
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Affiliation(s)
- Adela Horakova
- Department of Genetics and Reproductive Biotechnologies, Veterinary Research Institute, 621 00 Brno, Czech Republic
- Institute of Animal Physiology and Genetics, Czech Academy of Science, 277 21 Libechov, Czech Republic
- Faculty of Science, Masaryk University, 602 00 Brno, Czech Republic
| | - Marketa Konecna
- Department of Genetics and Reproductive Biotechnologies, Veterinary Research Institute, 621 00 Brno, Czech Republic
- Institute of Animal Physiology and Genetics, Czech Academy of Science, 277 21 Libechov, Czech Republic
- Faculty of Science, Masaryk University, 602 00 Brno, Czech Republic
| | - Martin Anger
- Department of Genetics and Reproductive Biotechnologies, Veterinary Research Institute, 621 00 Brno, Czech Republic
- Institute of Animal Physiology and Genetics, Czech Academy of Science, 277 21 Libechov, Czech Republic
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2
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Hino T, Kusakabe H. A reliable technique for karyotyping mouse oocytes prepared by a gradual fixation/air-drying method followed by multicolour FISH. Biol Open 2023; 12:bio060188. [PMID: 38088190 PMCID: PMC10732245 DOI: 10.1242/bio.060188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Accepted: 11/15/2023] [Indexed: 12/18/2023] Open
Abstract
Chromosome segregation errors during oocyte meiosis increase with age and lead to aneuploidy; hence, the mechanism has been studied extensively. The mouse is the most widely used experimental animal for this purpose. However, the lack of a reliable and efficient technique for karyotyping mouse oocytes has limited comprehensive studies of chromosome-specific segregation errors in this animal model. Here, we developed a novel karyotyping technique for mouse oocytes by applying multicolour fluorescence in situ hybridisation (FISH) to chromosome slides prepared by a gradual fixation/air-drying method, which is best suited to avoid rupture of oocyte membrane and artificial loss of chromosomes. The success rate of karyotyping meiosis I and II oocytes was about 30%, which improved to over 90% when the oocytes were 'flattened' during fixation and the chromosome specimens were denatured at 4°C. When this technique was applied to the karyotyping of meiosis II oocytes from aged female mice and from young female mice injected with colchicine, more than 80% of the oocytes were successfully karyotyped and the number of chromosomes was identified on all aberrant chromosomes. In conclusion, our technique allows for the efficient and reliable karyotyping of mouse oocytes.
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Affiliation(s)
- Toshiaki Hino
- Department of Biological Sciences, Asahikawa Medical University, Midorigaoka-Higashi 2-1-1-1, Asahikawa 078–8510, Japan
| | - Hirokazu Kusakabe
- Department of Biological Sciences, Asahikawa Medical University, Midorigaoka-Higashi 2-1-1-1, Asahikawa 078–8510, Japan
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3
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Baumann C, Zhang X, Kandasamy MK, Mei X, Chen S, Tehrani KF, Mortensen LJ, Watford W, Lall A, De La Fuente R. Acute irradiation induces a senescence-like chromatin structure in mammalian oocytes. Commun Biol 2023; 6:1258. [PMID: 38086992 PMCID: PMC10716162 DOI: 10.1038/s42003-023-05641-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Accepted: 11/27/2023] [Indexed: 12/18/2023] Open
Abstract
The mechanisms leading to changes in mesoscale chromatin organization during cellular aging are unknown. Here, we used transcriptional activator-like effectors, RNA-seq and superresolution analysis to determine the effects of genotoxic stress on oocyte chromatin structure. Major satellites are organized into tightly packed globular structures that coalesce into chromocenters and dynamically associate with the nucleolus. Acute irradiation significantly enhanced chromocenter mobility in transcriptionally inactive oocytes. In transcriptionally active oocytes, irradiation induced a striking unfolding of satellite chromatin fibers and enhanced the expression of transcripts required for protection from oxidative stress (Fermt1, Smg1), recovery from DNA damage (Tlk2, Rad54l) and regulation of heterochromatin assembly (Zfp296, Ski-oncogene). Non-irradiated, senescent oocytes exhibit not only high chromocenter mobility and satellite distension but also a high frequency of extra chromosomal satellite DNA. Notably, analysis of biological aging using an oocyte-specific RNA clock revealed cellular communication, posttranslational protein modifications, chromatin and histone dynamics as the top cellular processes that are dysregulated in both senescent and irradiated oocytes. Our results indicate that unfolding of heterochromatin fibers following acute genotoxic stress or cellular aging induced the formation of distended satellites and that abnormal chromatin structure together with increased chromocenter mobility leads to chromosome instability in senescent oocytes.
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Affiliation(s)
- Claudia Baumann
- Department of Physiology and Pharmacology, College of Veterinary Medicine, University of Georgia, Athens, GA, USA
- Regenerative Biosciences Center (RBC), University of Georgia, Athens, GA, USA
| | - Xiangyu Zhang
- Department of Physiology and Pharmacology, College of Veterinary Medicine, University of Georgia, Athens, GA, USA
- Regenerative Biosciences Center (RBC), University of Georgia, Athens, GA, USA
| | | | - Xiaohan Mei
- Department of Physiology and Pharmacology, College of Veterinary Medicine, University of Georgia, Athens, GA, USA
- Division of Surgical Research, University of Missouri, School of Medicine, Columbia, MO, USA
- Weill Cornell Medical College, New York, NY, USA
| | - Shiyou Chen
- Department of Physiology and Pharmacology, College of Veterinary Medicine, University of Georgia, Athens, GA, USA
- Division of Surgical Research, University of Missouri, School of Medicine, Columbia, MO, USA
| | - Kayvan F Tehrani
- Regenerative Biosciences Center (RBC), University of Georgia, Athens, GA, USA
- School of Chemical, Materials and Biomedical Engineering, University of Georgia, Athens, GA, USA
- University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Luke J Mortensen
- Regenerative Biosciences Center (RBC), University of Georgia, Athens, GA, USA
- School of Chemical, Materials and Biomedical Engineering, University of Georgia, Athens, GA, USA
| | - Wendy Watford
- Department of Infectious Diseases, University of Georgia, Athens, GA, USA
| | - Ashley Lall
- Department of Physiology and Pharmacology, College of Veterinary Medicine, University of Georgia, Athens, GA, USA
- Regenerative Biosciences Center (RBC), University of Georgia, Athens, GA, USA
| | - Rabindranath De La Fuente
- Department of Physiology and Pharmacology, College of Veterinary Medicine, University of Georgia, Athens, GA, USA.
- Regenerative Biosciences Center (RBC), University of Georgia, Athens, GA, USA.
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4
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Okamoto R, Xiao W, Fukasawa H, Hirata S, Sankai T, Masuyama H, Otsuki J. Aggregated chromosomes/chromatin transfer: a novel approach for mitochondrial replacement with minimal mitochondrial carryover: the implications of mouse experiments for human aggregated chromosome transfer. Mol Hum Reprod 2023; 29:gaad043. [PMID: 38039159 DOI: 10.1093/molehr/gaad043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Revised: 11/01/2023] [Indexed: 12/03/2023] Open
Abstract
Nuclear transfer techniques, including spindle chromosome complex (SC) transfer and pronuclear transfer, have been employed to mitigate mitochondrial diseases. Nevertheless, the challenge of mitochondrial DNA (mtDNA) carryover remains unresolved. Previously, we introduced a method for aggregated chromosome (AC) transfer in human subjects, offering a potential solution. However, the subsequent rates of embryonic development have remained unexplored owing to legal limitations in Japan, and animal studies have been hindered by a lack of AC formation in other species. Building upon our success in generating ACs within mouse oocytes via utilization of the phosphodiesterase inhibitor 3-isobutyl 1-methylxanthine (IBMX), this study has established a mouse model for AC transfer. Subsequently, a comparative analysis of embryo development rates and mtDNA carryover between AC transfer and SC transfer was conducted. Additionally, the mitochondrial distribution around SC and AC structures was investigated, revealing that in oocytes at the metaphase II stage, the mitochondria exhibited a relatively concentrated arrangement around the spindle apparatus, while the distribution of mitochondria in AC-formed oocytes appeared to be independent of the AC position. The AC transfer approach produced a marked augmentation in rates of fertilization, embryo cleavage, and blastocyst formation, especially as compared to scenarios without AC transfer in IBMX-treated AC-formed oocytes. No significant disparities in fertilization and embryo development rates were observed between AC and SC transfers. However, relative real-time PCR analyses revealed that the mtDNA carryover for AC transfers was one-tenth and therefore significantly lower than that of SC transfers. This study successfully accomplished nuclear transfers with ACs in mouse oocytes, offering an insight into the potential of AC transfers as a solution to heteroplasmy-related challenges. These findings are promising in terms of future investigation with human oocytes, thus advancing AC transfer as an innovative approach in the field of human nuclear transfer methodology.
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Affiliation(s)
- R Okamoto
- Department of Obstetrics and Gynecology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Kita, Okayama, Japan
| | - W Xiao
- Department of Applied Animal Science, Graduate School of Environmental, Life, Natural Science and Technology, Okayama University, Kita, Okayama, Japan
| | - H Fukasawa
- Department of Obstetrics and Gynecology, Faculty of Medicine, University of Yamanashi, Chuo, Yamanashi, Japan
| | - S Hirata
- Department of Obstetrics and Gynecology, Faculty of Medicine, University of Yamanashi, Chuo, Yamanashi, Japan
| | - T Sankai
- Tsukuba Primate Research Center, National Institutes of Biomedical Innovation, Health and Nutrition, Tsukuba, Ibaraki, Japan
| | - H Masuyama
- Department of Obstetrics and Gynecology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Kita, Okayama, Japan
| | - J Otsuki
- Department of Applied Animal Science, Graduate School of Environmental, Life, Natural Science and Technology, Okayama University, Kita, Okayama, Japan
- Assisted Reproductive Technology Center, Okayama University, Kita, Okayama, Japan
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5
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Mihajlović AI, Byers C, Reinholdt L, FitzHarris G. Spindle assembly checkpoint insensitivity allows meiosis-II despite chromosomal defects in aged eggs. EMBO Rep 2023; 24:e57227. [PMID: 37795949 PMCID: PMC10626445 DOI: 10.15252/embr.202357227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Revised: 09/07/2023] [Accepted: 09/19/2023] [Indexed: 10/06/2023] Open
Abstract
Chromosome segregation errors in mammalian oocyte meiosis lead to developmentally compromised aneuploid embryos and become more common with advancing maternal age. Known contributors include age-related chromosome cohesion loss and spindle assembly checkpoint (SAC) fallibility in meiosis-I. But how effective the SAC is in meiosis-II and how this might contribute to age-related aneuploidy is unknown. Here, we developed genetic and pharmacological approaches to directly address the function of the SAC in meiosis-II. We show that the SAC is insensitive in meiosis-II oocytes and that as a result misaligned chromosomes are randomly segregated. Whilst SAC ineffectiveness in meiosis-II is not age-related, it becomes most prejudicial in oocytes from older females because chromosomes that prematurely separate by age-related cohesion loss become misaligned in meiosis-II. We show that in the absence of a robust SAC in meiosis-II these age-related misaligned chromatids are missegregated and lead to aneuploidy. Our data demonstrate that the SAC fails to prevent cell division in the presence of misaligned chromosomes in oocyte meiosis-II, which explains how age-related cohesion loss can give rise to aneuploid embryos.
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Affiliation(s)
| | - Candice Byers
- The Institute for Experiential AI, Roux InstituteNortheastern UniversityPortlandMEUSA
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Zhang FL, Li WD, Zhu KX, Zhou X, Li L, Lee TL, Shen W. Aging-related aneuploidy is associated with mitochondrial imbalance and failure of spindle assembly. Cell Death Discov 2023; 9:235. [PMID: 37422452 DOI: 10.1038/s41420-023-01539-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Revised: 06/17/2023] [Accepted: 06/29/2023] [Indexed: 07/10/2023] Open
Abstract
Despite aging is closely linked to increased aneuploidy in the oocytes, the mechanism of how aging affects aneuploidy remains largely elusive. Here, we applied single-cell parallel methylation and transcriptome sequencing (scM&T-seq) data from the aging mouse oocyte model to decode the genomic landscape of oocyte aging. We found a decline in oocyte quality in aging mice, as manifested by a significantly lower rate of first polar body exclusion (P < 0.05), and dramatically increasing aneuploidy rate (P < 0.01). Simultaneously, scM&T data suggested that a large number of differential expression genes (DEGs) and differential methylation regions (DMRs) were obtained. Next, we identified strong association of spindle assembly and mitochondrial transmembrane transport during oocyte aging. Moreover, we verified the DEGs related to spindle assembly (such as Naip1, Aspm, Racgap1, Zfp207) by real-time quantitative PCR (RT-qPCR) and checked the mitochondrial dysfunction by JC-1 staining. Pearson correlation analysis found that receptors for mitochondrial function were strongly positively correlated with abnormal spindle assembly (P < 0.05). In conclusion, these results suggested that the mitochondrial dysfunction and abnormal spindle assembly of aging oocytes ultimately may lead to increased oocyte aneuploidy.
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Affiliation(s)
- Fa-Li Zhang
- College of Life Sciences, Key Laboratory of Animal Reproduction and Biotechnology in Universities of Shandong, Qingdao Agricultural University, 266109, Qingdao, China
- College of Animal Science and Veterinary Medicine, Shandong Agricultural University, 271018, Tai'an, China
| | - Wei-Dong Li
- Advanced Medical Research Institute, Shandong University, Jinan, China
- Center for Reproductive Medicine, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Ke-Xin Zhu
- College of Life Sciences, Key Laboratory of Animal Reproduction and Biotechnology in Universities of Shandong, Qingdao Agricultural University, 266109, Qingdao, China
| | - Xu Zhou
- Advanced Medical Research Institute, Shandong University, Jinan, China
- Center for Reproductive Medicine, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Lan Li
- College of Life Sciences, Key Laboratory of Animal Reproduction and Biotechnology in Universities of Shandong, Qingdao Agricultural University, 266109, Qingdao, China
| | - Tin-Lap Lee
- Developmental and Regenerative Biology Program, School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong, China.
- EggLoigcs Limited. Hong Kong Science and Technology Park, Shatin, Hong Kong, China.
| | - Wei Shen
- College of Life Sciences, Key Laboratory of Animal Reproduction and Biotechnology in Universities of Shandong, Qingdao Agricultural University, 266109, Qingdao, China.
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7
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Gu Y, Xu J, Sun F, Cheng J. Elevated intracellular pH of zygotes during mouse aging causes mitochondrial dysfunction associated with poor embryo development. Mol Cell Endocrinol 2023:111991. [PMID: 37336488 DOI: 10.1016/j.mce.2023.111991] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Revised: 06/02/2023] [Accepted: 06/13/2023] [Indexed: 06/21/2023]
Abstract
The mortality of preimplantation embryos is positively correlated with maternal age. However, the underlying mechanism for the poor quality of embryos remains unclear. Here, we found that aging caused elevated intracellular pH (pHi) in zygotes, which could trigger aberrant mitochondrial membrane potential, increased reactive oxygen species (ROS) levels, and poor embryo development. Moreover, single-cell transcriptome sequencing of mouse zygotes identified 120 genes that were significantly differentially expressed (DE) between young and older zygotes. These include genes such as Slc14a1, Fxyd5, CD74, and Bst, which are related to cell division, ion transporter, and cell differentiation. Further analysis indicated that these DE genes were enriched in apoptosis, the NF-kappa B signaling pathway, and the chemokine signaling pathway, which might be the key regulatory pathway affecting the quality of zygotes and subsequent embryo development. Taken together, our study helps elucidate the poor quality and development of older preimplantation embryos.
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Affiliation(s)
- Yimin Gu
- Institute of Reproductive Medicine, School of Medicine, Nantong University, Nantong, 226001, China
| | - Junjie Xu
- Institute of Reproductive Medicine, School of Medicine, Nantong University, Nantong, 226001, China; Department of Obstetrics and Gynecology, The Second Hospital of Shanxi Medical University, 7, Taiyuan, 030001, China
| | - Fei Sun
- Institute of Reproductive Medicine, School of Medicine, Nantong University, Nantong, 226001, China.
| | - Jinmei Cheng
- Institute of Reproductive Medicine, School of Medicine, Nantong University, Nantong, 226001, China.
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8
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Wang X, Wang L, Xiang W. Mechanisms of ovarian aging in women: a review. J Ovarian Res 2023; 16:67. [PMID: 37024976 PMCID: PMC10080932 DOI: 10.1186/s13048-023-01151-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2022] [Accepted: 03/29/2023] [Indexed: 04/08/2023] Open
Abstract
Ovarian aging is a natural and physiological aging process characterized by loss of quantity and quality of oocyte or follicular pool. As it is generally accepted that women are born with a finite follicle pool that will go through constant decline without renewing, which, together with decreased oocyte quality, makes a severe situation for women who is of advanced age but desperate for a healthy baby. The aim of our review was to investigate mechanisms leading to ovarian aging by discussing both extra- and intra- ovarian factors and to identify genetic characteristics of ovarian aging. The mechanisms were identified as both extra-ovarian alternation of hypothalamic-pituitary-ovarian axis and intra-ovarian alternation of ovary itself, including telomere, mitochondria, oxidative stress, DNA damage, protein homeostasis, aneuploidy, apoptosis and autophagy. Moreover, here we reviewed related Genome-wide association studies (GWAS studies) from 2009 to 2021 and next generation sequencing (NGS) studies of primary ovarian insufficiency (POI) in order to describe genetic characteristics of ovarian aging. It is reasonable to wish more reliable anti-aging interventions for ovarian aging as the exploration of mechanisms and genetics being progressing.
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Affiliation(s)
- Xiangfei Wang
- Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Lingjuan Wang
- Department of Obstetrics and Gynecology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Wenpei Xiang
- Institute of Reproductive Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China.
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9
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KYOGOKU H, KITAJIMA TS. The large cytoplasmic volume of oocyte. J Reprod Dev 2023; 69:1-9. [PMID: 36436912 PMCID: PMC9939283 DOI: 10.1262/jrd.2022-101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
The study of the size of cells and organelles has a long history, dating back to the 1600s when cells were defined. In particular, various methods have elucidated the size of the nucleus and the mitotic spindle in several species. However, little research has been conducted on oocyte size and organelles in mammals, and many questions remain to be answered. The appropriate size is essential to cell function properly. Oocytes have a very large cytoplasm, which is more than 100 times larger than that of general somatic cells in mammals. In this review, we discuss how oocytes acquire an enormous cytoplasmic size and the adverse effects of a large cytoplasmic size on cellular functions.
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Affiliation(s)
- Hirohisa KYOGOKU
- Graduate School of Agricultural Science, Kobe University, Kobe 657-8501, Japan,Laboratory for Chromosome Segregation, RIKEN Center for Biosystems Dynamics Research, Kobe 650-0047, Japan
| | - Tomoya S KITAJIMA
- Laboratory for Chromosome Segregation, RIKEN Center for Biosystems Dynamics Research, Kobe 650-0047, Japan
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Satouh Y, Sato K. Reorganization, specialization, and degradation of oocyte maternal components for early development. Reprod Med Biol 2023; 22:e12505. [PMID: 36726596 PMCID: PMC9884333 DOI: 10.1002/rmb2.12505] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 01/07/2023] [Accepted: 01/12/2023] [Indexed: 01/30/2023] Open
Abstract
Background Oocyte components are maternally provided, solely determine oocyte quality, and coordinately determine embryo quality with zygotic gene expression. During oocyte maturation, maternal organelles are drastically reorganized and specialized to support oocyte characteristics. A large number of maternal components are actively degraded after fertilization and gradually replaced by zygotic gene products. The molecular basis and the significance of these processes on oocyte/embryo quality are not fully understood. Methods Firstly, recent findings in organelle characteristics of other cells or oocytes from model organisms are introduced for further understanding of oocyte organelle reorganization/specialization. Secondly, recent progress in studies on maternal components degradation and their molecular mechanisms are introduced. Finally, future applications of these advancements for predicting mammalian oocyte/embryo quality are discussed. Main findings The significance of cellular surface protein degradation via endocytosis for embryonic development, and involvement of biogenesis of lipid droplets in embryonic quality, were recently reported using mammalian model organisms. Conclusion Identifying key oocyte component characteristics and understanding their dynamics may lead to new applications in oocyte/embryo quality prediction and improvement. To implement these multidimensional concepts, development of new technical approaches that allow us to address the complexity and efficient studies using model organisms are required.
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Affiliation(s)
- Yuhkoh Satouh
- Laboratory of Molecular Traffic, Institute for Molecular and Cellular RegulationGunma UniversityMaebashiJapan
| | - Ken Sato
- Laboratory of Molecular Traffic, Institute for Molecular and Cellular RegulationGunma UniversityMaebashiJapan
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11
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Charalambous C, Webster A, Schuh M. Aneuploidy in mammalian oocytes and the impact of maternal ageing. Nat Rev Mol Cell Biol 2023; 24:27-44. [PMID: 36068367 DOI: 10.1038/s41580-022-00517-3] [Citation(s) in RCA: 27] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/05/2022] [Indexed: 11/09/2022]
Abstract
During fertilization, the egg and the sperm are supposed to contribute precisely one copy of each chromosome to the embryo. However, human eggs frequently contain an incorrect number of chromosomes - a condition termed aneuploidy, which is much more prevalent in eggs than in either sperm or in most somatic cells. In turn, aneuploidy in eggs is a leading cause of infertility, miscarriage and congenital syndromes. Aneuploidy arises as a consequence of aberrant meiosis during egg development from its progenitor cell, the oocyte. In human oocytes, chromosomes often segregate incorrectly. Chromosome segregation errors increase in women from their mid-thirties, leading to even higher levels of aneuploidy in eggs from women of advanced maternal age, ultimately causing age-related infertility. Here, we cover the two main areas that contribute to aneuploidy: (1) factors that influence the fidelity of chromosome segregation in eggs of women from all ages and (2) factors that change in response to reproductive ageing. Recent discoveries reveal new error-causing pathways and present a framework for therapeutic strategies to extend the span of female fertility.
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Affiliation(s)
- Chloe Charalambous
- Department of Meiosis, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Alexandre Webster
- Department of Meiosis, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Melina Schuh
- Department of Meiosis, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany.
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12
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Hashimoto S, Morimoto Y. Mitochondrial function of human embryo: Decline in their quality with maternal aging. Reprod Med Biol 2022; 21:e12491. [PMID: 36570768 PMCID: PMC9769491 DOI: 10.1002/rmb2.12491] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 11/15/2022] [Accepted: 11/23/2022] [Indexed: 12/24/2022] Open
Abstract
Background Female fertility declines with age, due to increased chromosomal aneuploidy and possible reduced mitochondrial function in the embryo. Methods This review outlines how mitochondrial function in human embryos, as predicted from oxygen consumption rate (OCR) measurements, changes in preimplantation stage, and what factors, particularly maternal age, affect mitochondrial function in embryos. Main findings The structure of the mitochondrial inner membrane and its respiratory function developed with embryo development, while the copy number of mitochondrial DNA per specimen was transiently reduced compared with that of the oocyte. The undifferentiated state of the inner cell mass cells appears to be associated with a low OCR. In contrast, the copy number of mitochondrial DNA increased in trophoblast cells and mitochondrial aerobic metabolism increased.The OCRs at morulae stage decreased with maternal age, but there was no relationship between maternal age and the copy number of mitochondrial DNA at any stages. The higher oxygen spent at the morula stage; the shorter time was needed for development to the mid-stage blastocyst. Conclusions The mitochondrial respiratory function of human embryos developed along with embryonic growth. Mitochondrial function at morula stage declined with their maternal age and reduced mitochondrial function decreased the rate of development from morula to blastocyst.
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Affiliation(s)
- Shu Hashimoto
- Graduate School of MedicineOsaka Metropolitan UniversityOsakaJapan
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13
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Chromosome Inequality: Causes and Consequences of Non-Random Segregation Errors in Mitosis and Meiosis. Cells 2022; 11:cells11223564. [PMID: 36428993 PMCID: PMC9688425 DOI: 10.3390/cells11223564] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 11/01/2022] [Accepted: 11/08/2022] [Indexed: 11/16/2022] Open
Abstract
Aneuploidy is a hallmark of cancer and a major cause of miscarriages in humans. It is caused by chromosome segregation errors during cell divisions. Evidence is mounting that the probability of specific chromosomes undergoing a segregation error is non-random. In other words, some chromosomes have a higher chance of contributing to aneuploid karyotypes than others. This could have important implications for the origins of recurrent aneuploidy patterns in cancer and developing embryos. Here, we review recent progress in understanding the prevalence and causes of non-random chromosome segregation errors in mammalian mitosis and meiosis. We evaluate its potential impact on cancer and human reproduction and discuss possible research avenues.
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14
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Currie CE, Ford E, Benham Whyte L, Taylor DM, Mihalas BP, Erent M, Marston AL, Hartshorne GM, McAinsh AD. The first mitotic division of human embryos is highly error prone. Nat Commun 2022; 13:6755. [PMID: 36347869 PMCID: PMC9643329 DOI: 10.1038/s41467-022-34294-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Accepted: 10/20/2022] [Indexed: 11/09/2022] Open
Abstract
Human beings are made of ~50 trillion cells which arise from serial mitotic divisions of a single cell - the fertilised egg. Remarkably, the early human embryo is often chromosomally abnormal, and many are mosaic, with the karyotype differing from one cell to another. Mosaicism presumably arises from chromosome segregation errors during the early mitotic divisions, although these events have never been visualised in living human embryos. Here, we establish live cell imaging of chromosome segregation using normally fertilised embryos from an egg-share-to-research programme, as well as embryos deselected during fertility treatment. We reveal that the first mitotic division has an extended prometaphase/metaphase and exhibits phenotypes that can cause nondisjunction. These included multipolar chromosome segregations and lagging chromosomes that lead to formation of micronuclei. Analysis of nuclear number and size provides evidence of equivalent phenotypes in 2-cell human embryos that gave rise to live births. Together this shows that errors in the first mitotic division can be tolerated in human embryos and uncovers cell biological events that contribute to preimplantation mosaicism.
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Affiliation(s)
- Cerys E. Currie
- grid.7372.10000 0000 8809 1613Division of Biomedical Sciences, Warwick Medical School, University of Warwick, Coventry, CV4 7AL UK ,grid.7372.10000 0000 8809 1613Centre for Mechanochemical Cell Biology, University of Warwick, Coventry, CV4 7AL UK
| | - Emma Ford
- grid.7372.10000 0000 8809 1613Division of Biomedical Sciences, Warwick Medical School, University of Warwick, Coventry, CV4 7AL UK ,grid.7372.10000 0000 8809 1613Centre for Mechanochemical Cell Biology, University of Warwick, Coventry, CV4 7AL UK
| | - Lucy Benham Whyte
- grid.15628.380000 0004 0393 1193University Hospitals Coventry and Warwickshire NHS Trust, Coventry, CV2 2DX UK ,Present Address: Kings Fertility Ltd, Fetal Medicine Research Institute, 16-20 Windsor Walk, SE5 8SS London, UK
| | - Deborah M. Taylor
- grid.15628.380000 0004 0393 1193University Hospitals Coventry and Warwickshire NHS Trust, Coventry, CV2 2DX UK
| | - Bettina P. Mihalas
- grid.4305.20000 0004 1936 7988Wellcome Centre for Cell Biology, University of Edinburgh, Edinburgh, UK
| | - Muriel Erent
- grid.7372.10000 0000 8809 1613Division of Biomedical Sciences, Warwick Medical School, University of Warwick, Coventry, CV4 7AL UK ,grid.7372.10000 0000 8809 1613Centre for Mechanochemical Cell Biology, University of Warwick, Coventry, CV4 7AL UK
| | - Adele L. Marston
- grid.4305.20000 0004 1936 7988Wellcome Centre for Cell Biology, University of Edinburgh, Edinburgh, UK
| | - Geraldine M. Hartshorne
- grid.7372.10000 0000 8809 1613Division of Biomedical Sciences, Warwick Medical School, University of Warwick, Coventry, CV4 7AL UK ,grid.15628.380000 0004 0393 1193University Hospitals Coventry and Warwickshire NHS Trust, Coventry, CV2 2DX UK ,grid.7372.10000 0000 8809 1613Centre for Early Life, University of Warwick, Coventry, CV4 7AL UK
| | - Andrew D. McAinsh
- grid.7372.10000 0000 8809 1613Division of Biomedical Sciences, Warwick Medical School, University of Warwick, Coventry, CV4 7AL UK ,grid.7372.10000 0000 8809 1613Centre for Mechanochemical Cell Biology, University of Warwick, Coventry, CV4 7AL UK ,grid.7372.10000 0000 8809 1613Centre for Early Life, University of Warwick, Coventry, CV4 7AL UK
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15
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Yun Y, Lee S, So C, Manhas R, Kim C, Wibowo T, Hori M, Hunter N. Oocyte Development and Quality in Young and Old Mice following Exposure to Atrazine. ENVIRONMENTAL HEALTH PERSPECTIVES 2022; 130:117007. [PMID: 36367780 PMCID: PMC9651182 DOI: 10.1289/ehp11343] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2022] [Revised: 10/10/2022] [Accepted: 10/17/2022] [Indexed: 06/01/2023]
Abstract
BACKGROUND Egg development has unique features that render it vulnerable to environmental perturbation. The herbicide atrazine is an endocrine disruptor shown to have detrimental effects on reproduction across several vertebrate species. OBJECTIVES This study was designed to determine whether exposure to low levels of atrazine impairs meiosis in female mammals, using a mouse model; in particular, the study's researchers sought to determine whether and how the fidelity of oocyte chromosome segregation may be affected and whether aging-related aneuploidy is exacerbated. METHODS Female C57BL/6J mice were exposed to two levels of atrazine in drinking water: The higher level equaled aqueous saturation, and the lower level corresponded to detected environmental contamination. To model developmental exposure, atrazine was ingested by pregnant females at 0.5 d post coitum and continued until pups were weaned at 21 d postpartum. For adult exposure, 2-month-old females ingested atrazine for 3 months. Following exposure, various indicators of oocyte development and quality were determined, including: a) chromosome synapsis and crossing over in fetal oocytes using immunofluorescence staining of prophase-I chromosome preparations; b) sizes of follicle pools in sectioned ovaries; c) efficiencies of in vitro fertilization and early embryogenesis; d) chromosome alignment and segregation in cultured oocytes; e) chromosomal errors in metaphase-I and -II (MI and MII) preparations; and f) sister-chromatid cohesion via immunofluorescence intensity of cohesin subunit REC8 on MI-chromosome preparations, and measurement of interkinetochore distances in MII preparations. RESULTS Mice exposed to atrazine during development showed slightly higher levels of defects in chromosome synapsis, but sizes of initial follicle pools were indistinguishable from controls. However, although more eggs were ovulated, oocyte quality was lower. At the chromosome level, frequencies of spindle misalignment and numerical and structural abnormalities were greater at both meiotic divisions. In vitro fertilization was less efficient, and there were more apoptotic cells in blastocysts derived from eggs of atrazine-exposed females. Similar levels of chromosomal defects were seen in oocytes following both developmental and adult exposure regimens, suggesting quiescent primordial follicles may be a consequential target of atrazine. An important finding was that defects were observed long after exposure was terminated. Moreover, chromosomally abnormal eggs were very frequent in older mice, implying that atrazine exposure during development exacerbates effects of maternal aging on oocyte quality. Indeed, analogous to the effects of maternal age, weaker cohesion between sister chromatids was observed in oocytes from atrazine-exposed animals. CONCLUSION Low-level atrazine exposure caused persistent changes to the female mammalian germline in mice, with potential consequences for reproductive lifespan and congenital disease. https://doi.org/10.1289/EHP11343.
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Affiliation(s)
- Yan Yun
- Department of Microbiology and Molecular Genetics, University of California, Davis, Davis, California, USA
- Howard Hughes Medical Institute, University of California, Davis, Davis, California, USA
| | - Sunkyung Lee
- Department of Microbiology and Molecular Genetics, University of California, Davis, Davis, California, USA
| | - Christina So
- Department of Microbiology and Molecular Genetics, University of California, Davis, Davis, California, USA
| | - Rushali Manhas
- Department of Microbiology and Molecular Genetics, University of California, Davis, Davis, California, USA
| | - Carol Kim
- Department of Microbiology and Molecular Genetics, University of California, Davis, Davis, California, USA
| | - Tabitha Wibowo
- Department of Microbiology and Molecular Genetics, University of California, Davis, Davis, California, USA
| | - Michael Hori
- Department of Microbiology and Molecular Genetics, University of California, Davis, Davis, California, USA
| | - Neil Hunter
- Department of Microbiology and Molecular Genetics, University of California, Davis, Davis, California, USA
- Howard Hughes Medical Institute, University of California, Davis, Davis, California, USA
- Department of Molecular and Cellular Biology, University of California, Davis, Davis, California, USA
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16
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Wu T, Gu H, Luo Y, Wang L, Sang Q. Meiotic defects in human oocytes: Potential causes and clinical implications. Bioessays 2022; 44:e2200135. [PMID: 36207289 DOI: 10.1002/bies.202200135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 09/14/2022] [Accepted: 09/16/2022] [Indexed: 11/09/2022]
Abstract
Meiotic defects cause abnormal chromosome segregation leading to aneuploidy in mammalian oocytes. Chromosome segregation is particularly error-prone in human oocytes, but the mechanisms behind such errors remain unclear. To explain the frequent chromosome segregation errors, recent investigations have identified multiple meiotic defects and explained how these defects occur in female meiosis. In particular, we review the causes of cohesin exhaustion, leaky spindle assembly checkpoint (SAC), inherently unstable meiotic spindle, fragmented kinetochores or centromeres, abnormal aurora kinases (AURK), and clinical genetic variants in human oocytes. We mainly focus on meiotic defects in human oocytes, but also refer to the potential defects of female meiosis in mouse models.
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Affiliation(s)
- Tianyu Wu
- Institute of Pediatrics, Children's Hospital of Fudan University and Institutes of Biomedical Sciences, the State Key Laboratory of Genetic Engineering, Fudan University, Shanghai, China
| | - Hao Gu
- Institute of Pediatrics, Children's Hospital of Fudan University and Institutes of Biomedical Sciences, the State Key Laboratory of Genetic Engineering, Fudan University, Shanghai, China
| | - Yuxi Luo
- Institute of Pediatrics, Children's Hospital of Fudan University and Institutes of Biomedical Sciences, the State Key Laboratory of Genetic Engineering, Fudan University, Shanghai, China
| | - Lei Wang
- Institute of Pediatrics, Children's Hospital of Fudan University and Institutes of Biomedical Sciences, the State Key Laboratory of Genetic Engineering, Fudan University, Shanghai, China
| | - Qing Sang
- Institute of Pediatrics, Children's Hospital of Fudan University and Institutes of Biomedical Sciences, the State Key Laboratory of Genetic Engineering, Fudan University, Shanghai, China
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17
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Mouse oocytes carrying metacentric Robertsonian chromosomes have fewer crossover sites and higher aneuploidy rates than oocytes carrying acrocentric chromosomes alone. Sci Rep 2022; 12:12028. [PMID: 35835815 PMCID: PMC9283534 DOI: 10.1038/s41598-022-16175-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2021] [Accepted: 07/06/2022] [Indexed: 12/03/2022] Open
Abstract
Meiotic homologous recombination during fetal development dictates proper chromosome segregation in adult mammalian oocytes. Successful homologous synapsis and recombination during Meiotic Prophase I (MPI) depends on telomere-led chromosome movement along the nuclear envelope. In mice, all chromosomes are acrocentric, while other mammalian species carry a mixture of acrocentric and metacentric chromosomes. Such differences in telomeric structures may explain the exceptionally low aneuploidy rates in mice. Here, we tested whether the presence of metacentric chromosomes carrying Robertsonian translocations (RbT) affects the rate of homologous recombination or aneuploidy. We found a delay in MPI progression in RbT-carrier vs. wild-type (WT) fetal ovaries. Furthermore, resolution of distal telomere clusters, associated with synapsis initiation, was delayed and centromeric telomere clusters persisted until later MPI substages in RbT-carrier oocytes compared to WT oocytes. When chromosomes fully synapsed, higher percentages of RbT-carrier oocytes harbored at least one chromosome pair lacking MLH1 foci, which indicate crossover sites, compared to WT oocytes. Aneuploidy rates in ovulated eggs were also higher in RbT-carrier females than in WT females. In conclusion, the presence of metacentric chromosomes among acrocentric chromosomes in mouse oocytes delays MPI progression and reduces the efficiency of homologous crossover, resulting in a higher frequency of aneuploidy.
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18
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Ogonuki N, Kyogoku H, Hino T, Osawa Y, Fujiwara Y, Inoue K, Kunieda T, Mizuno S, Tateno H, Sugiyama F, Kitajima TS, Ogura A. Birth of mice from meiotically arrested spermatocytes following biparental meiosis in halved oocytes. EMBO Rep 2022; 23:e54992. [DOI: 10.15252/embr.202254992] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Revised: 04/01/2022] [Accepted: 04/19/2022] [Indexed: 01/05/2023] Open
Affiliation(s)
- Narumi Ogonuki
- Bioresource Engineering Division RIKEN BioResource Research Center Ibaraki Japan
| | - Hirohisa Kyogoku
- Laboratory for Chromosome Segregation RIKEN Center for Biosystems Dynamics Research Kobe Japan
- Graduate School of Agricultural Science Kobe University Kobe Japan
| | - Toshiaki Hino
- Department of Biological Sciences Asahikawa Medical University Asahikawa Japan
| | - Yuki Osawa
- Graduate School of Comprehensive Human Sciences University of Tsukuba Tsukuba Japan
| | - Yasuhiro Fujiwara
- Laboratory of Pathology and Development Institute for Quantitative Biosciences The University of Tokyo Tokyo Japan
| | - Kimiko Inoue
- Bioresource Engineering Division RIKEN BioResource Research Center Ibaraki Japan
- Graduate School of Life and Environmental Sciences University of Tsukuba Tsukuba Japan
| | - Tetsuo Kunieda
- Faculty of Veterinary Medicine Okayama University of Science Imabari Japan
| | - Seiya Mizuno
- Laboratory Animal Resource Center and Trans‐border Medical Research Center Faculty of Medicine University of Tsukuba Tsukuba Japan
| | - Hiroyuki Tateno
- Department of Biological Sciences Asahikawa Medical University Asahikawa Japan
| | - Fumihiro Sugiyama
- Laboratory Animal Resource Center and Trans‐border Medical Research Center Faculty of Medicine University of Tsukuba Tsukuba Japan
| | - Tomoya S Kitajima
- Laboratory for Chromosome Segregation RIKEN Center for Biosystems Dynamics Research Kobe Japan
| | - Atsuo Ogura
- Bioresource Engineering Division RIKEN BioResource Research Center Ibaraki Japan
- Graduate School of Life and Environmental Sciences University of Tsukuba Tsukuba Japan
- RIKEN Cluster for Pioneering Research Wako Japan
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19
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Kouznetsova A, Liu JG, Valentiniene S, Brismar H, Höög C. Age-dependent aneuploidy in mammalian oocytes instigated at the second meiotic division. Aging Cell 2022; 21:e13649. [PMID: 35665589 PMCID: PMC9282850 DOI: 10.1111/acel.13649] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Revised: 02/07/2022] [Accepted: 05/18/2022] [Indexed: 11/08/2022] Open
Abstract
Ageing severely affects the chromosome segregation process in human oocytes resulting in aneuploidy, infertility and developmental disorders. A considerable amount of segregation errors in humans are introduced at the second meiotic division. We have here compared the chromosome segregation process in young adult and aged female mice during the second meiotic division. More than half of the oocytes in aged mice displayed chromosome segregation irregularities at anaphase II, resulting in dramatically increased level of aneuploidy in haploid gametes, from 4% in young adult mice to 30% in aged mice. We find that the post‐metaphase II process that efficiently corrects aberrant kinetochore‐microtubule attachments in oocytes in young adult mice is approximately 10‐fold less efficient in aged mice, in particular affecting chromosomes that show small inter‐centromere distances at the metaphase II stage in aged mice. Our results reveal that post‐metaphase II processes have critical impact on age‐dependent aneuploidy in mammalian eggs.
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Affiliation(s)
- Anna Kouznetsova
- Department of Cell and Molecular Biology Karolinska Institutet Stockholm Sweden
| | - Jian Guo Liu
- Department of Cell and Molecular Biology Karolinska Institutet Stockholm Sweden
| | - Sonata Valentiniene
- Department of Cell and Molecular Biology Karolinska Institutet Stockholm Sweden
| | - Hjalmar Brismar
- Science for Life Laboratory, Department of Applied Physics Royal Institute of Technology Solna Sweden
| | - Christer Höög
- Department of Cell and Molecular Biology Karolinska Institutet Stockholm Sweden
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20
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Ishiguro KI. Sexually Dimorphic Properties in Meiotic Chromosome. Sex Dev 2022; 16:423-434. [PMID: 35130542 DOI: 10.1159/000520682] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Accepted: 10/22/2021] [Indexed: 07/20/2023] Open
Abstract
BACKGROUND Meiosis is a crucial process for germ cell development. It consists of 1 round of DNA replication followed by 2 rounds of chromosome segregation, producing haploid gametes from diploid cells. During meiotic prophase, chromosomes are organized into axis-loop structures, which underlie meiosis-specific events such as meiotic recombination and homolog synapsis. Meiosis-specific cohesin plays a pivotal role in establishing higher-order chromosome architecture and regulating chromosome dynamics. SUMMARY Notably, sexually dimorphic properties of chromosome architecture are prominent during meiotic prophase, despite the same axial proteins being conserved between male and female. The difference in chromosome structure between the sexes gives sexual differences in the regulation of meiotic recombination and crossover distribution. KEY MESSAGES This review mainly focuses on the sexual differences of meiosis from the viewpoint of chromosome structure in mammals, elucidating the differences in meiotic recombination and homolog synapsis between the sexes.
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Affiliation(s)
- Kei-Ichiro Ishiguro
- Department of Chromosome Biology, Institute of Molecular Embryology and Genetics (IMEG), Kumamoto University, Kumamoto, Japan
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21
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Nambu M, Kishikawa A, Yamada T, Ichikawa K, Kira Y, Itabashi Y, Honda A, Yamada K, Murakami H, Yamamoto A. Direct evaluation of cohesin-mediated sister kinetochore associations at meiosis I in fission yeast. J Cell Sci 2022; 135:jcs259102. [PMID: 34851403 DOI: 10.1242/jcs.259102] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Accepted: 11/16/2021] [Indexed: 11/20/2022] Open
Abstract
Kinetochores drive chromosome segregation by mediating chromosome interactions with the spindle. In higher eukaryotes, sister kinetochores are separately positioned on opposite sides of sister centromeres during mitosis, but associate with each other during meiosis I. Kinetochore association facilitates the attachment of sister chromatids to the same pole, enabling the segregation of homologous chromosomes toward opposite poles. In the fission yeast, Schizosaccharomyces pombe, Rec8-containing meiotic cohesin is suggested to establish kinetochore associations by mediating cohesion of the centromere cores. However, cohesin-mediated kinetochore associations on intact chromosomes have never been demonstrated directly. In the present study, we describe a novel method for the direct evaluation of kinetochore associations on intact chromosomes in live S. pombe cells, and demonstrate that sister kinetochores and the centromere cores are positioned separately on mitotic chromosomes but associate with each other on meiosis I chromosomes. Furthermore, we demonstrate that kinetochore association depends on meiotic cohesin and the cohesin regulators Moa1 and Mrc1, and requires mating-pheromone signaling for its establishment. These results confirm cohesin-mediated kinetochore association and its regulatory mechanisms, along with the usefulness of the developed method for its analysis. This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Masashi Nambu
- Graduate School of Integrated Science and Technology, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529, Japan
| | - Atsuki Kishikawa
- Graduate School of Integrated Science and Technology, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529, Japan
| | - Takatomi Yamada
- Department of Biological Sciences, Faculty of Science and Engineering, Chuo University, 1-13-27 Kasuga, Bunkyo-ku, Tokyo 112-8551, Japan
| | - Kento Ichikawa
- Graduate School of Integrated Science and Technology, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529, Japan
| | - Yunosuke Kira
- Faculty of Science, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529, Japan
| | - Yuta Itabashi
- Graduate School of Integrated Science and Technology, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529, Japan
| | - Akira Honda
- Graduate School of Integrated Science and Technology, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529, Japan
| | - Kohei Yamada
- Graduate School of Integrated Science and Technology, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529, Japan
| | - Hiroshi Murakami
- Department of Biological Sciences, Faculty of Science and Engineering, Chuo University, 1-13-27 Kasuga, Bunkyo-ku, Tokyo 112-8551, Japan
| | - Ayumu Yamamoto
- Graduate School of Integrated Science and Technology, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529, Japan
- Faculty of Science, Shizuoka University, 836 Ohya, Suruga-ku, Shizuoka 422-8529, Japan
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22
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Li L, Xia Y, Yang Y, Zhang W, Yan H, Yin P, Li K, Chen Y, Lu L, Tong G. CDC26 is a key factor in human oocyte aging. Hum Reprod 2021; 36:3095-3107. [PMID: 34590680 DOI: 10.1093/humrep/deab217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Revised: 08/01/2021] [Indexed: 11/13/2022] Open
Abstract
STUDY QUESTION Is CDC26 a key factor in human oocyte aging? SUMMARY ANSWER The lack of CDC26 disrupts the oocytes maturation process, leading to oocyte aging, but these defects could be partially rescued by overexpression of the CDC26 protein. WHAT IS KNOWN ALREADY Age-related oocyte aging is the main cause of female fertility decline. In mammalian oocytes, aberrant meiosis can cause chromosomal abnormalities that might lead to infertility and developmental disorders. CDC26 participates in the meiosis process. STUDY DESIGN, SIZE, DURATION Differential gene expression in young and old women oocytes were screened by single-cell RNA-seq technology, and the functions of differentially genes were verified on mouse oocytes. Finally, transfection technology was used to evaluate the effect of a differentially expressed gene in rescuing human oocyte from aging. PARTICIPANTS/MATERIALS, SETTING, METHODS Discarded human oocytes were collected for single-cell RNA-seq, q-PCR and immunocytochemical analyses to screen for and identify differential gene expression. Female KM mice oocytes were collected for IVM of oocytes, q-PCR and immunocytochemical analyses to delineate the relationships between oocyte aging and differential gene expression. Additionally, recombinant lentiviral vectors encoding CDC26 were transfected into the germinal vesicle oocytes of older women, to investigate the effects of the CDC26 gene expression on oocyte development. MAIN RESULTS AND THE ROLE OF CHANCE Many genes were found to be differentially expressed in the oocytes of young versus old patients via RNA-seq technology. CDC26 mRNA and protein levels in aged oocytes were severely decreased, when compared with the levels observed in young oocytes. Moreover, aged oocytes lacking CDC26 were more prone to aneuploidy. These defects in aged oocytes could be partially rescued by overexpression of the CDC26 protein. LARGE SCALE DATA N/A. LIMITATIONS, REASONS FOR CAUTION Our study delineated key steps in the oocyte aging process by identifying the key role of CDC26 in the progression of oocyte maturation. Future studies are required to address whether other signaling pathways play a role in regulating oocyte maturation via CDC26 and which genes are the direct molecular targets of CDC26. WIDER IMPLICATIONS OF THE FINDINGS Our results using in vitro systems for both mouse and human oocyte maturation provide a proof of principle that CDC26 may represent a novel therapeutic approach against maternal aging-related spindle and chromosomal abnormalities. STUDY FUNDING/COMPETING INTEREST(S) This work was supported by grants from the National Natural Science Foundation of China (81571442 and 81170571), the outstanding Talent Project of Shanghai Municipal Commission of Health (XBR2011067) and Clinical Research and Cultivation Project in Shanghai Municipal Hospitals (SHDC12019X32). The authors declare no conflict of interest.
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Affiliation(s)
- Li Li
- Reproductive Medicine Center, Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Ye Xia
- Reproductive Medicine Center, Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Yang Yang
- Reproductive Medicine Center, Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Wuwen Zhang
- Reproductive Medicine Center, Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Hua Yan
- Reproductive Medicine Center, Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Ping Yin
- Reproductive Medicine Center, Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Kai Li
- Reproductive Medicine Center, Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Yuanyuan Chen
- Reproductive Medicine Center, Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Lu Lu
- Reproductive Medicine Center, Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Guoqing Tong
- Reproductive Medicine Center, Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine, Shanghai, China
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23
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Distinct classes of lagging chromosome underpin age-related oocyte aneuploidy in mouse. Dev Cell 2021; 56:2273-2283.e3. [PMID: 34428397 DOI: 10.1016/j.devcel.2021.07.022] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 06/07/2021] [Accepted: 07/29/2021] [Indexed: 12/18/2022]
Abstract
Chromosome segregation errors that cause oocyte aneuploidy increase in frequency with maternal age and are considered a major contributing factor of age-related fertility decline in females. Lagging anaphase chromosomes are a common age-associated phenomenon in oocytes, but whether anaphase laggards actually missegregate and cause aneuploidy is unclear. Here, we show that lagging chromosomes in mouse oocytes comprise two mechanistically distinct classes of chromosome motion that we refer to as "class-I" and "class-II" laggards. We use imaging approaches and mechanistic interventions to dissociate the two classes and find that whereas class-II laggards are largely benign, class-I laggards frequently directly lead to aneuploidy. Most notably, a controlled prolongation of meiosis I specifically lessens class-I lagging to prevent aneuploidy. Our data thus reveal lagging chromosomes to be a cause of age-related aneuploidy in mouse oocytes and suggest that manipulating the cell cycle could increase the yield of useful oocytes in some contexts.
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24
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Mishina T, Tabata N, Hayashi T, Yoshimura M, Umeda M, Mori M, Ikawa Y, Hamada H, Nikaido I, Kitajima TS. Single-oocyte transcriptome analysis reveals aging-associated effects influenced by life stage and calorie restriction. Aging Cell 2021; 20:e13428. [PMID: 34245092 PMCID: PMC8373347 DOI: 10.1111/acel.13428] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 06/11/2021] [Accepted: 06/17/2021] [Indexed: 12/13/2022] Open
Abstract
Chromosome segregation errors in oocytes lead to the production of aneuploid eggs, which are the leading cause of pregnancy loss and of several congenital diseases such as Down syndrome. The frequency of chromosome segregation errors in oocytes increases with maternal age, especially at a late stage of reproductive life. How aging at various life stages affects oocytes differently remains poorly understood. In this study, we describe aging‐associated changes in the transcriptome profile of mouse oocytes throughout reproductive life. Our single‐oocyte comprehensive RNA sequencing using RamDA‐seq revealed that oocytes undergo transcriptome changes at a late reproductive stage, whereas their surrounding cumulus cells exhibit transcriptome changes at an earlier stage. Calorie restriction, a paradigm that reportedly prevents aging‐associated egg aneuploidy, promotes a transcriptome shift in oocytes with the up‐regulation of genes involved in chromosome segregation. This shift is accompanied by the improved maintenance of chromosomal cohesin, the loss of which is a hallmark of oocyte aging and causes chromosome segregation errors. These findings have implications for understanding how oocytes undergo aging‐associated functional decline throughout their reproductive life in a context‐dependent manner.
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Affiliation(s)
- Tappei Mishina
- Laboratory for Chromosome Segregation RIKEN Center for Biosystems Dynamics Research (BDR) Kobe Japan
| | - Namine Tabata
- Laboratory for Chromosome Segregation RIKEN Center for Biosystems Dynamics Research (BDR) Kobe Japan
- Graduate School of Biostudies Kyoto University Kyoto Japan
| | - Tetsutaro Hayashi
- Laboratory for Bioinformatics Research RIKEN Center for Biosystems Dynamics Research (BDR) Kobe Japan
| | - Mika Yoshimura
- Laboratory for Bioinformatics Research RIKEN Center for Biosystems Dynamics Research (BDR) Kobe Japan
| | - Mana Umeda
- Laboratory for Bioinformatics Research RIKEN Center for Biosystems Dynamics Research (BDR) Kobe Japan
| | - Masashi Mori
- Laboratory for Chromosome Segregation RIKEN Center for Biosystems Dynamics Research (BDR) Kobe Japan
| | - Yayoi Ikawa
- Laboratory for Organismal Patterning RIKEN Center for Biosystems Dynamics Research (BDR) Kobe Japan
| | - Hiroshi Hamada
- Laboratory for Organismal Patterning RIKEN Center for Biosystems Dynamics Research (BDR) Kobe Japan
| | - Itoshi Nikaido
- Laboratory for Bioinformatics Research RIKEN Center for Biosystems Dynamics Research (BDR) Kobe Japan
- Department of Functional Genome Informatics, Division of Medical Genomics, Medical Research Institute Tokyo Medical and Dental University (TMDU) Bunkyo Japan
- Master's/Doctoral Program in Life Science Innovation (Bioinformatics), Degree Programs in Systems and Information Engineering, Graduate School of Science and Technology University of Tsukuba Tsukuba Japan
| | - Tomoya S. Kitajima
- Laboratory for Chromosome Segregation RIKEN Center for Biosystems Dynamics Research (BDR) Kobe Japan
- Graduate School of Biostudies Kyoto University Kyoto Japan
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25
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Chatzidaki EE, Powell S, Dequeker BJH, Gassler J, Silva MCC, Tachibana K. Ovulation suppression protects against chromosomal abnormalities in mouse eggs at advanced maternal age. Curr Biol 2021; 31:4038-4051.e7. [PMID: 34314679 DOI: 10.1016/j.cub.2021.06.076] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Revised: 04/01/2021] [Accepted: 06/25/2021] [Indexed: 01/09/2023]
Abstract
The frequency of egg aneuploidy and trisomic pregnancies increases with maternal age. To what extent individual approaches can delay the "maternal age effect" is unclear because multiple causes contribute to chromosomal abnormalities in mammalian eggs. We propose that ovulation frequency determines the physiological aging of oocytes, a key aspect of which is the ability to accurately segregate chromosomes and produce euploid eggs. To test this hypothesis, ovulations were reduced using successive pregnancies, hormonal contraception, and a pre-pubertal knockout mouse model, and the effects on chromosome segregation and egg ploidy were examined. We show that each intervention reduces chromosomal abnormalities in eggs of aged mice, suggesting that ovulation reduction delays oocyte aging. The protective effect can be partly explained by retention of chromosomal Rec8-cohesin that maintains sister chromatid cohesion in meiosis. In addition, single-nucleus Hi-C (snHi-C) revealed deterioration in the 3D chromatin structure including an increase in extruded loop sizes in long-lived oocytes. Artificial cleavage of Rec8 is sufficient to increase extruded loop sizes, suggesting that cohesin complexes maintaining cohesion restrict loop extrusion. These findings suggest that ovulation suppression protects against Rec8 loss, thereby maintaining both sister chromatid cohesion and 3D chromatin structure and promoting production of euploid eggs. We conclude that the maternal age effect can be delayed in mice. An implication of this work is that long-term ovulation-suppressing conditions can potentially reduce the risk of aneuploid pregnancies at advanced maternal age.
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Affiliation(s)
- Emmanouella E Chatzidaki
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences, Vienna BioCenter, Dr. Bohr-Gasse 3, 1030 Vienna, Austria
| | - Sean Powell
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences, Vienna BioCenter, Dr. Bohr-Gasse 3, 1030 Vienna, Austria
| | - Bart J H Dequeker
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences, Vienna BioCenter, Dr. Bohr-Gasse 3, 1030 Vienna, Austria
| | - Johanna Gassler
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences, Vienna BioCenter, Dr. Bohr-Gasse 3, 1030 Vienna, Austria
| | - Mariana C C Silva
- Research Institute of Molecular Pathology, Campus Vienna BioCenter 1, 1030 Vienna, Austria
| | - Kikuë Tachibana
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences, Vienna BioCenter, Dr. Bohr-Gasse 3, 1030 Vienna, Austria; Department of Totipotency, Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Munich, Germany.
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26
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Chico-Sordo L, Córdova-Oriz I, Polonio AM, S-Mellado LS, Medrano M, García-Velasco JA, Varela E. Reproductive aging and telomeres: Are women and men equally affected? Mech Ageing Dev 2021; 198:111541. [PMID: 34245740 DOI: 10.1016/j.mad.2021.111541] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 07/01/2021] [Accepted: 07/05/2021] [Indexed: 02/06/2023]
Abstract
Successful reproduction is very important for individuals and for society. Currently, the human health span and lifespan are the object of intense and productive investigation with great achievements, compared to the last century. However, reproduction span does not progress concomitantly with lifespan. Reproductive organs age, decreasing the levels of sexual hormones, which are protectors of health through their action on several organs of the body. Thus, this is the starting point of the organismal decay and infertility. This starting point is easily detected in women. In men, it goes under the surface, undetected, but it goes, nevertheless. Regarding fertility, aging alters the hormonal equilibrium, decreases the potential of reproductive organs, diminishes the quality of the gametes and worsen the reproductive outcomes. All these events happen at a different pace and affecting different organs in women and men. The question is what molecular pathways are involved in reproductive aging and if there is a possible halting or even reversion of the aging events. Answers to all these points will be explained in the present review.
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Affiliation(s)
- Lucía Chico-Sordo
- IVI Foundation, Instituto de Investigación Sanitaria La Fe (IISLAFE), Valencia, Spain; Instituto de Investigación Sanitaria La Fe, Valencia, Spain.
| | - Isabel Córdova-Oriz
- IVI Foundation, Instituto de Investigación Sanitaria La Fe (IISLAFE), Valencia, Spain; Instituto de Investigación Sanitaria La Fe, Valencia, Spain.
| | - Alba María Polonio
- IVI Foundation, Instituto de Investigación Sanitaria La Fe (IISLAFE), Valencia, Spain; Instituto de Investigación Sanitaria La Fe, Valencia, Spain.
| | - Lucía Sánchez S-Mellado
- IVI Foundation, Instituto de Investigación Sanitaria La Fe (IISLAFE), Valencia, Spain; Instituto de Investigación Sanitaria La Fe, Valencia, Spain.
| | - Marta Medrano
- IVI Foundation, Instituto de Investigación Sanitaria La Fe (IISLAFE), Valencia, Spain; IVIRMA Madrid, Spain.
| | - Juan Antonio García-Velasco
- IVI Foundation, Instituto de Investigación Sanitaria La Fe (IISLAFE), Valencia, Spain; Instituto de Investigación Sanitaria La Fe, Valencia, Spain; IVIRMA Madrid, Spain; Rey Juan Carlos University, Madrid, Spain.
| | - Elisa Varela
- IVI Foundation, Instituto de Investigación Sanitaria La Fe (IISLAFE), Valencia, Spain; Instituto de Investigación Sanitaria La Fe, Valencia, Spain; Rey Juan Carlos University, Madrid, Spain.
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27
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Kawano H, Yamashita N, Ito J, Kashiwazaki N. Chromosomal analyses of human giant diploid oocytes by next-generation sequencing. Reprod Med Biol 2021; 20:260-266. [PMID: 34262393 PMCID: PMC8254173 DOI: 10.1002/rmb2.12378] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2020] [Revised: 02/12/2021] [Accepted: 03/04/2021] [Indexed: 11/08/2022] Open
Abstract
PURPOSE Although giant oocytes (GOs) having about twice cytoplasmic volume compared with general oocytes in mammals including the human are rarely recovered, it is thought that GOs have potentially chromosomal abnormalities. The aim of the present study was to assess chromosome numbers in chromosome-spindle complexes (CSCs) and polar bodies of human GOs by using micromanipulation for sampling and next-generation sequencing (NGS) for analyses of the chromosome numbers. METHODS When recovered oocytes whose cytoplasm has lager than 140 µm or above, the oocytes were defined as GOs, and recovered GOs were vitrified. After warming, the CSCs, polar bodies, and enucleated cytoplasm were collected by micromanipulation from 3 GOs. The collected samples were analyzed by NGS. RESULTS Chromosomal aneuploidy in the GOs was confirmed in all the three GOs. Comparing the CSCs with the chromosomes from polar bodies, the deletion and overlapping chromosome numbers were complementary in each GO. CONCLUSIONS The authors could collect the CSCs and the polar bodies from human GOs by micromanipulation, and then could analyze the chromosome numbers of the GOs by NGS method. As our data suggest that human GOs have chromosomal abnormalities, GOs should be excluded from clinical purpose as gamete sources for embryo transfer in the human.
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Affiliation(s)
- Hiroomi Kawano
- Laboratory of Animal ReproductionGraduate School of Veterinary ScienceAzabu UniversitySagamiharaJapan
- Yamashita Shonan Yume ClinicFujisawaJapan
| | | | - Junya Ito
- Laboratory of Animal ReproductionGraduate School of Veterinary ScienceAzabu UniversitySagamiharaJapan
| | - Naomi Kashiwazaki
- Laboratory of Animal ReproductionGraduate School of Veterinary ScienceAzabu UniversitySagamiharaJapan
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28
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Ma W, Zhou J, Chen J, Carr AM, Watanabe Y. Meikin synergizes with shugoshin to protect cohesin Rec8 during meiosis I. Genes Dev 2021; 35:692-697. [PMID: 33888556 PMCID: PMC8091969 DOI: 10.1101/gad.348052.120] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Accepted: 03/03/2021] [Indexed: 12/03/2022]
Abstract
The conserved meiosis-specific kinetochore regulator, meikin (Moa1 in fission yeast) plays a central role in establishing meiosis-specific kinetochore function. However, the underlying molecular mechanisms remain elusive. Here, we show how Moa1 regulates centromeric cohesion protection, a function that has been previously attributed to shugoshin (Sgo1). Moa1 is known to associate with Plo1 kinase. We explore Plo1-dependent Rec8 phosphorylation and identify a key phosphorylation site required for cohesion protection. The phosphorylation of Rec8 by Moa1-Plo1 potentiates the activity of PP2A associated with Sgo1. This leads to dephosphorylation of Rec8 at another site, which thereby prevents cleavage of Rec8 by separase.
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Affiliation(s)
- Wei Ma
- Science Center for Future Foods, Jiangnan University, Wuxi, Jiangsu 214122, China
| | - Jingwen Zhou
- Science Center for Future Foods, Jiangnan University, Wuxi, Jiangsu 214122, China
| | - Jian Chen
- Science Center for Future Foods, Jiangnan University, Wuxi, Jiangsu 214122, China
| | - Antony M Carr
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Brighton BN1 9RQ, United Kingdom
| | - Yoshinori Watanabe
- Science Center for Future Foods, Jiangnan University, Wuxi, Jiangsu 214122, China
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Brighton BN1 9RQ, United Kingdom
- Cell Cycle Laboratory, The Francis Crick Institute, London NW1 1AT, United Kingdom
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29
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Wartosch L, Schindler K, Schuh M, Gruhn JR, Hoffmann ER, McCoy RC, Xing J. Origins and mechanisms leading to aneuploidy in human eggs. Prenat Diagn 2021; 41:620-630. [PMID: 33860956 PMCID: PMC8237340 DOI: 10.1002/pd.5927] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 01/02/2021] [Accepted: 02/21/2021] [Indexed: 11/18/2022]
Abstract
The gain or loss of a chromosome-or aneuploidy-acts as one of the major triggers for infertility and pregnancy loss in humans. These chromosomal abnormalities affect more than 40% of eggs in women at both ends of the age spectrum, that is, young girls as well as women of advancing maternal age. Recent studies in human oocytes and embryos using genomics, cytogenetics, and in silico modeling all provide new insight into the rates and potential genetic and cellular factors associated with aneuploidy at varying stages of development. Here, we review recent studies that are shedding light on potential molecular mechanisms of chromosome missegregation in oocytes and embryos across the entire female reproductive life span.
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Affiliation(s)
- Lena Wartosch
- Department of MeiosisMax Planck Institute for Biophysical ChemistryGöttingenGermany
| | - Karen Schindler
- Department of GeneticsRutgers, The State University of New JerseyPiscatawayNew JerseyUSA
- Human Genetics Institute of New JerseyRutgers, The State University of New JerseyPiscatawayNew JerseyUSA
| | - Melina Schuh
- Department of MeiosisMax Planck Institute for Biophysical ChemistryGöttingenGermany
| | - Jennifer R. Gruhn
- DNRF Center for Chromosome StabilityDepartment of Cellular and Molecular MedicineFaculty of Health and Medical SciencesUniversity of CopenhagenDenmark
| | - Eva R. Hoffmann
- DNRF Center for Chromosome StabilityDepartment of Cellular and Molecular MedicineFaculty of Health and Medical SciencesUniversity of CopenhagenDenmark
| | - Rajiv C. McCoy
- Department of BiologyJohns Hopkins UniversityBaltimoreMarylandUSA
| | - Jinchuan Xing
- Department of GeneticsRutgers, The State University of New JerseyPiscatawayNew JerseyUSA
- Human Genetics Institute of New JerseyRutgers, The State University of New JerseyPiscatawayNew JerseyUSA
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30
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Courtois A, Yoshida S, Takenouchi O, Asai K, Kitajima TS. Stable kinetochore-microtubule attachments restrict MTOC position and spindle elongation in oocytes. EMBO Rep 2021; 22:e51400. [PMID: 33655692 PMCID: PMC8024892 DOI: 10.15252/embr.202051400] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 01/14/2021] [Accepted: 01/28/2021] [Indexed: 01/13/2023] Open
Abstract
In mouse oocytes, acentriolar MTOCs functionally replace centrosomes and act as microtubule nucleation sites. Microtubules nucleated from MTOCs initially assemble into an unorganized ball‐like structure, which then transforms into a bipolar spindle carrying MTOCs at its poles, a process called spindle bipolarization. In mouse oocytes, spindle bipolarization is promoted by kinetochores but the mechanism by which kinetochore–microtubule attachments contribute to spindle bipolarity remains unclear. This study demonstrates that the stability of kinetochore–microtubule attachment is essential for confining MTOC positions at the spindle poles and for limiting spindle elongation. MTOC sorting is gradual and continues even in the metaphase spindle. When stable kinetochore–microtubule attachments are disrupted, the spindle is unable to restrict MTOCs at its poles and fails to terminate its elongation. Stable kinetochore fibers are directly connected to MTOCs and to the spindle poles. These findings suggest a role for stable kinetochore–microtubule attachments in fine‐tuning acentrosomal spindle bipolarity.
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Affiliation(s)
- Aurélien Courtois
- Laboratory for Chromosome Segregation, RIKEN Center for Biosystems Dynamics Research (BDR), Kobe, Japan
| | - Shuhei Yoshida
- Laboratory for Chromosome Segregation, RIKEN Center for Biosystems Dynamics Research (BDR), Kobe, Japan
| | - Osamu Takenouchi
- Laboratory for Chromosome Segregation, RIKEN Center for Biosystems Dynamics Research (BDR), Kobe, Japan
| | - Kohei Asai
- Laboratory for Chromosome Segregation, RIKEN Center for Biosystems Dynamics Research (BDR), Kobe, Japan.,Graduate School of Biostudies, Kyoto University, Kyoto, Japan
| | - Tomoya S Kitajima
- Laboratory for Chromosome Segregation, RIKEN Center for Biosystems Dynamics Research (BDR), Kobe, Japan.,Graduate School of Biostudies, Kyoto University, Kyoto, Japan
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31
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Aneuploidy in human eggs: contributions of the meiotic spindle. Biochem Soc Trans 2021; 49:107-118. [PMID: 33449109 PMCID: PMC7925012 DOI: 10.1042/bst20200043] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Revised: 12/03/2020] [Accepted: 12/11/2020] [Indexed: 12/12/2022]
Abstract
Human eggs frequently contain an incorrect number of chromosomes, a condition termed aneuploidy. Aneuploidy affects ∼10-25% of eggs in women in their early 30s, and more than 50% of eggs from women over 40. Most aneuploid eggs cannot develop to term upon fertilization, making aneuploidy in eggs a leading cause of miscarriages and infertility. The cellular origins of aneuploidy in human eggs are incompletely understood. Aneuploidy arises from chromosome segregation errors during the two meiotic divisions of the oocyte, the progenitor cell of the egg. Chromosome segregation is driven by a microtubule spindle, which captures and separates the paired chromosomes during meiosis I, and sister chromatids during meiosis II. Recent studies reveal that defects in the organization of the acentrosomal meiotic spindle contribute to human egg aneuploidy. The microtubules of the human oocyte spindle are very frequently incorrectly attached to meiotic kinetochores, the multi-protein complexes on chromosomes to which microtubules bind. Multiple features of human oocyte spindles favour incorrect attachments. These include spindle instability and many age-related changes in chromosome and kinetochore architecture. Here, we review how the unusual spindle assembly mechanism in human oocytes contributes to the remarkably high levels of aneuploidy in young human eggs, and how age-related changes in chromosome and kinetochore architecture cause aneuploidy levels to rise even higher as women approach their forties.
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32
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Chuang TH, Chang YP, Lee MJ, Wang HL, Lai HH, Chen SU. The Incidence of Mosaicism for Individual Chromosome in Human Blastocysts Is Correlated With Chromosome Length. Front Genet 2021; 11:565348. [PMID: 33488666 PMCID: PMC7815765 DOI: 10.3389/fgene.2020.565348] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Accepted: 11/30/2020] [Indexed: 12/18/2022] Open
Abstract
Mosaicism, known as partial aneuploidies, mostly originates from mitotic errors during the post-zygotic stage; it consists of different cell lineages within a human embryo. The incidence of mosaicism has not been shown to correlate with maternal age, and its correlation with individual chromosome characteristics has not been well investigated. In this study, the results of preimplantation genetic testing for aneuploidy (PGT-A) derived from 4,036 blastocysts (930 IVF couples) were collected from 2015 to 2017. Via next-generation sequencing for comprehensive chromosome screening, embryo ploidy was identified as aneuploid, mosaic, and euploid. Total mosaicism was classified into two categories: "mosaic euploid/aneuploidy" (with mosaic aneuploidy between 20 and 80%) and "mosaic and aneuploidy" (a uniformly abnormal embryo superimposed with mosaic aneuploidies). Frequency of mosaicism was analyzed according to the function of chromosomal lengths, which divides involved chromosomes into three groups: group A (156-249 Mb), group B (102-145 Mb), and group C (51-90 Mb). The results show that the aneuploidy was more frequent in group C than in group A and group B (A: 23.7%, B: 35.1, 41.2%, p < 0.0001), while the mosaicism was more frequent in group A and group B than in group C [(Mosaic euploid/aneuploid) A: 14.6%, B: 12.4%, C: 9.9%, p < 0.0001; (mosaic and aneuploid) A: 21.3%, B: 22.9%, C: 18.9%, p < 0.0001; (Total mosaicism) A: 35.9%, B: 35.3%, C: 28.8%, p < 0.0001]. The significantly higher frequency of aneuploidy was on the shorter chromosome (< 90 Mb), and that of mosaicism was on the longer chromosomes (> 100 Mb). The length association did not reach significance in the patients with advanced age (≥ 36 years), and of the chromosome-specific mosaicism rate, the highest prevalence was on chromosome 14 (5.8%), 1 (5.7%), and 9 (5.6%). Although the length association was observed via group comparison, there may be affecting mechanisms other than chromosomes length. Eventually, twenty patients with mosaic embryo cryotransfers resulted in six live births. No significant correlation was observed between the transfer outcomes and chromosome length; however, the analysis was limited by small sample size.
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Affiliation(s)
- Tzu-Hsuan Chuang
- Stork Fertility Center, Stork Ladies Clinic, Hsinchu City, Taiwan
| | - Ya-Ping Chang
- Stork Fertility Center, Stork Ladies Clinic, Hsinchu City, Taiwan
| | - Meng-Ju Lee
- Stork Fertility Center, Stork Ladies Clinic, Hsinchu City, Taiwan
| | - Huai-Ling Wang
- Stork Fertility Center, Stork Ladies Clinic, Hsinchu City, Taiwan
| | - Hsing-Hua Lai
- Stork Fertility Center, Stork Ladies Clinic, Hsinchu City, Taiwan
| | - Shee-Uan Chen
- Department of Obstetrics and Gynecology, National Taiwan University Hospital and College of Medicine, Taipei City, Taiwan
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33
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Morimoto N, Hashimoto S, Yamanaka M, Satoh M, Nakaoka Y, Fukui A, Morimoto Y, Shibahara H. Treatment with Laevo (L)-carnitine reverses the mitochondrial function of human embryos. J Assist Reprod Genet 2020; 38:71-78. [PMID: 33070223 DOI: 10.1007/s10815-020-01973-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Accepted: 10/07/2020] [Indexed: 11/27/2022] Open
Abstract
PURPOSE Laevo (l)-carnitine plays important roles in reducing the cytotoxic effects of free fatty acids by forming acyl-carnitine and promoting beta-oxidation, leading to alleviation of cell damage. Recently, the mitochondrial functions in morula has been shown to decrease with the maternal age. Here, we assessed the effect of l-carnitine on mitochondrial function in human embryos and embryo development. METHODS To examine the effect of L-carnitine on mitochondrial function in morulae, 38 vitrified-thawed embryos at the 6-11-cell stage on day 3 after ICSI were donated from 19 couples. Each couple donated two embryos. Two siblings from each couple were divided randomly into two groups and were cultured in medium with or without 1 mM L-carnitine. The oxygen consumption rates (OCRs) were measured at morula stage. The development of 1029 zygotes cultured in medium with or without L-carnitine was prospectively analyzed. RESULTS Addition of L-carnitine to the culture medium significantly increased the OCRs of morulae and improved the morphologically-good blastocyst formation rate per zygote compared with sibling embryos. Twenty healthy babies were born from embryos cultured in L-carnitine-supplemented medium after single embryo transfers. CONCLUSION(S) L-carnitine is a promising culture medium supplement that might be able to counteract the decreased mitochondrial function in human morula stage embryos.
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Affiliation(s)
- Naoharu Morimoto
- IVF Namba Clinic, Osaka, 550-0015, Japan
- Graduate School of Medicine, Osaka City University, Osaka, 545-8585, Japan
- Department of Obstetrics and Gynecology, Hyogo College of Medicine, Nishinomiya, Hyogo, 663-8501, Japan
| | - Shu Hashimoto
- Graduate School of Medicine, Osaka City University, Osaka, 545-8585, Japan.
| | | | | | | | - Atsushi Fukui
- Department of Obstetrics and Gynecology, Hyogo College of Medicine, Nishinomiya, Hyogo, 663-8501, Japan
| | | | - Hiroaki Shibahara
- Department of Obstetrics and Gynecology, Hyogo College of Medicine, Nishinomiya, Hyogo, 663-8501, Japan
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34
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Trebichalská Z, Kyjovská D, Kloudová S, Otevřel P, Hampl A, Holubcová Z. Cytoplasmic maturation in human oocytes: an ultrastructural study †. Biol Reprod 2020; 104:106-116. [PMID: 33404651 PMCID: PMC7786262 DOI: 10.1093/biolre/ioaa174] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Revised: 09/07/2020] [Accepted: 09/15/2020] [Indexed: 12/24/2022] Open
Abstract
Female fertility relies on successful egg development. Besides chromosome segregation, complex structural and biochemical changes in the cytoplasmic compartment are necessary to confer the female gamete the capacity to undergo normal fertilization and sustain embryonic development. Despite the profound impact on egg quality, morphological bases of cytoplasmic maturation remain largely unknown. Here, we report our findings from the ultrastructural analysis of 69 unfertilized human oocytes from 34 young and healthy egg donors. By comparison of samples fixed at three consecutive developmental stages, we explored how ooplasmic architecture changes during meiotic maturation in vitro. The morphometric image analysis supported observation that the major reorganization of cytoplasm occurs before polar body extrusion. The organelles initially concentrated around prophase nucleus were repositioned toward the periphery and evenly distributed throughout the ooplasm. As maturation progressed, distinct secretory apparatus appeared to transform into cortical granules that clustered underneath the oocyte's surface. The most prominent feature was the gradual formation of heterologous complexes composed of variable elements of endoplasmic reticulum and multiple mitochondria with primitive morphology. Based on the generated image dataset, we proposed a morphological map of cytoplasmic maturation, which may serve as a reference for future comparative studies. In conclusion, this work improves our understanding of human oocyte morphology, cytoplasmic maturation, and intracellular factors defining human egg quality. Although this analysis involved spare oocytes completing development in vitro, it provides essential insight into the enigmatic process by which human egg progenitors prepare for fertilization.
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Affiliation(s)
- Z Trebichalská
- Department of Histology and Embryology, Faculty of Medicine, Masaryk University, Brno, Czech Republic
| | - D Kyjovská
- Reprofit International, Clinic of Reproductive Medicine, Brno, Czech Republic
| | - S Kloudová
- Reprofit International, Clinic of Reproductive Medicine, Brno, Czech Republic
| | - P Otevřel
- Reprofit International, Clinic of Reproductive Medicine, Brno, Czech Republic
| | - A Hampl
- Department of Histology and Embryology, Faculty of Medicine, Masaryk University, Brno, Czech Republic
| | - Z Holubcová
- Department of Histology and Embryology, Faculty of Medicine, Masaryk University, Brno, Czech Republic.,Reprofit International, Clinic of Reproductive Medicine, Brno, Czech Republic
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35
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Mitochondrial oxygen consumption rate of human embryos declines with maternal age. J Assist Reprod Genet 2020; 37:1815-1821. [PMID: 32740687 DOI: 10.1007/s10815-020-01869-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Accepted: 06/23/2020] [Indexed: 10/23/2022] Open
Abstract
PURPOSE The fertility of women decreases with age because of factors such as an increased incidence of aneuploidies and-possibly-decreased mitochondrial activity in oocytes. However, the relationship between maternal aging and mitochondrial function of their embryos remains unknown. Here, we assessed the relationship between maternal age and mitochondrial functions in their oocytes and embryos METHODS: The relationships between maternal age and oxygen consumption rates (OCRs), mitochondrial DNA (mtDNA) copy numbers, or blastocyst development was investigated using 81 embryos donated from 63 infertility couples. The developmental rates from morulae to blastocysts were retrospectively analyzed using data of 105 patients. RESULTS The OCRs of morulae decreased with maternal age (r2 = 0.48, P < 0.05) although there were no relationships between maternal age and mtDNA copy number in any stages. The more oxygen consumed at the morula stage, the shorter time was required for embryo development to the mid-stage blastocyst (r2 = 0.236, P < 0.05). According to the clinical data analysis, the developmental rate from morulae to blastocysts decreased with maternal age (P < 0.05, < 37 years, 81.1%, vs. ≥ 37 years, 64.1%). CONCLUSIONS The data of the present study revealed that mitochondrial function at the morula stage of human embryos decreased with their maternal age and a decrease of mitochondrial function led to slow-paced development and impaired developmental rate from morulae to blastocysts.
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36
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Mikwar M, MacFarlane AJ, Marchetti F. Mechanisms of oocyte aneuploidy associated with advanced maternal age. MUTATION RESEARCH. REVIEWS IN MUTATION RESEARCH 2020; 785:108320. [PMID: 32800274 DOI: 10.1016/j.mrrev.2020.108320] [Citation(s) in RCA: 119] [Impact Index Per Article: 29.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Revised: 06/24/2020] [Accepted: 06/29/2020] [Indexed: 12/30/2022]
Abstract
It is well established that maternal age is associated with a rapid decline in the production of healthy and high-quality oocytes resulting in reduced fertility in women older than 35 years of age. In particular, chromosome segregation errors during meiotic divisions are increasingly common and lead to the production of oocytes with an incorrect number of chromosomes, a condition known as aneuploidy. When an aneuploid oocyte is fertilized by a sperm it gives rise to an aneuploid embryo that, except in rare situations, will result in a spontaneous abortion. As females advance in age, they are at higher risk of infertility, miscarriage, or having a pregnancy affected by congenital birth defects such as Down syndrome (trisomy 21), Edwards syndrome (trisomy 18), and Turner syndrome (monosomy X). Here, we review the potential molecular mechanisms associated with increased chromosome segregation errors during meiosis as a function of maternal age. Our review shows that multiple exogenous and endogenous factors contribute to the age-related increase in oocyte aneuploidy. Specifically, the weight of evidence indicates that recombination failure, cohesin deterioration, spindle assembly checkpoint (SAC) disregulation, abnormalities in post-translational modification of histones and tubulin, and mitochondrial dysfunction are the leading causes of oocyte aneuploidy associated with maternal aging. There is also growing evidence that dietary and other bioactive interventions may mitigate the effect of maternal aging on oocyte quality and oocyte aneuploidy, thereby improving fertility outcomes. Maternal age is a major concern for aneuploidy and genetic disorders in the offspring in the context of an increasing proportion of mothers having children at increasingly older ages. A better understanding of the mechanisms associated with maternal aging leading to aneuploidy and of intervention strategies that may mitigate these detrimental effects and reduce its occurrence are essential for preventing abnormal reproductive outcomes in the human population.
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Affiliation(s)
- Myy Mikwar
- Department of Biology, Carleton University, Ottawa, Ontario, Canada; Nutrition Research Division, Health Canada, Ottawa, Ontario, Canada
| | - Amanda J MacFarlane
- Department of Biology, Carleton University, Ottawa, Ontario, Canada; Nutrition Research Division, Health Canada, Ottawa, Ontario, Canada
| | - Francesco Marchetti
- Department of Biology, Carleton University, Ottawa, Ontario, Canada; Mechanistic Studies Division, Health Canada, Ottawa, Ontario, Canada.
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Holton RA, Harris AM, Mukerji B, Singh T, Dia F, Berkowitz KM. CHTF18 ensures the quantity and quality of the ovarian reserve†. Biol Reprod 2020; 103:24-35. [PMID: 32219340 DOI: 10.1093/biolre/ioaa036] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Revised: 10/29/2019] [Accepted: 03/24/2020] [Indexed: 11/13/2022] Open
Abstract
The number and quality of oocytes, as well as the decline in both of these parameters with age, determines reproductive potential in women. However, the underlying mechanisms of this diminution are incompletely understood. Previously, we identified novel roles for CHTF18 (Chromosome Transmission Fidelity Factor 18), a component of the conserved Replication Factor C-like complex, in male fertility and gametogenesis. Currently, we reveal crucial roles for CHTF18 in female meiosis and oocyte development. Chtf18-/- female mice are subfertile and have fewer offspring beginning at 6 months of age. Consistent with age-dependent subfertility, Chtf18-/- ovaries contain fewer follicles at all stages of folliculogenesis than wild type ovaries, but the decreases are more significant at 3 and 6 months of age. By 6 months of age, both primordial and growing ovarian follicle pools are markedly reduced to near depletion. Chromosomal synapsis in Chtf18-/- oocytes is complete, but meiotic recombination is impaired resulting in persistent DNA double-strand breaks, fewer crossovers, and early homolog disjunction during meiosis I. Consistent with poor oocyte quality, the majority of Chtf18-/- oocytes fail to progress to metaphase II following meiotic resumption and a significant percentage of those that do progress are aneuploid. Collectively, our findings indicate critical functions for CHTF18 in ensuring both the quantity and quality of the mammalian oocyte pool.
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Affiliation(s)
| | | | | | - Tanu Singh
- Department of Biochemistry and Molecular Biology
| | - Ferdusy Dia
- Department of Biochemistry and Molecular Biology
| | - Karen M Berkowitz
- Department of Biochemistry and Molecular Biology.,Department of Obstetrics and Gynecology, Drexel University College of Medicine, Philadelphia, PA, USA
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38
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Lodge C, Herbert M. Oocyte aneuploidy-more tools to tackle an old problem. Proc Natl Acad Sci U S A 2020; 117:11850-11852. [PMID: 32430318 PMCID: PMC7275742 DOI: 10.1073/pnas.2005739117] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Chris Lodge
- Newcastle Fertility Centre, Biosciences Institute, Newcastle University, Newcastle upon Tyne NE1 4EP, United Kingdom
| | - Mary Herbert
- Newcastle Fertility Centre, Biosciences Institute, Newcastle University, Newcastle upon Tyne NE1 4EP, United Kingdom
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39
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Reichmann J, Dobie K, Lister LM, Crichton JH, Best D, MacLennan M, Read D, Raymond ES, Hung CC, Boyle S, Shirahige K, Cooke HJ, Herbert M, Adams IR. Tex19.1 inhibits the N-end rule pathway and maintains acetylated SMC3 cohesin and sister chromatid cohesion in oocytes. J Cell Biol 2020; 219:e201702123. [PMID: 32232464 PMCID: PMC7199850 DOI: 10.1083/jcb.201702123] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2017] [Revised: 12/31/2019] [Accepted: 02/11/2020] [Indexed: 12/14/2022] Open
Abstract
Age-dependent oocyte aneuploidy, a major cause of Down syndrome, is associated with declining sister chromatid cohesion in postnatal oocytes. Here we show that cohesion in postnatal mouse oocytes is regulated by Tex19.1. We show Tex19.1-/- oocytes have defects maintaining chiasmata, missegregate their chromosomes during meiosis, and transmit aneuploidies to the next generation. Furthermore, we show that mouse Tex19.1 inhibits N-end rule protein degradation mediated by its interacting partner UBR2, and that Ubr2 itself has a previously undescribed role in negatively regulating the acetylated SMC3 subpopulation of cohesin in mitotic somatic cells. Lastly, we show that acetylated SMC3 is associated with meiotic chromosome axes in mouse oocytes, and that this population of cohesin is specifically depleted in the absence of Tex19.1. These findings indicate that Tex19.1 regulates UBR protein activity to maintain acetylated SMC3 and sister chromatid cohesion in postnatal oocytes and prevent aneuploidy from arising in the female germline.
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Affiliation(s)
- Judith Reichmann
- Medical Research Council Human Genetics Unit, Medical Research Council Institute of Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Crewe Road, Edinburgh, UK
| | - Karen Dobie
- Medical Research Council Human Genetics Unit, Medical Research Council Institute of Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Crewe Road, Edinburgh, UK
| | - Lisa M. Lister
- Institute for Genetic Medicine, Newcastle University, Biomedicine West Wing, Centre for Life, Newcastle upon Tyne, UK
| | - James H. Crichton
- Medical Research Council Human Genetics Unit, Medical Research Council Institute of Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Crewe Road, Edinburgh, UK
| | - Diana Best
- Medical Research Council Human Genetics Unit, Medical Research Council Institute of Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Crewe Road, Edinburgh, UK
| | - Marie MacLennan
- Medical Research Council Human Genetics Unit, Medical Research Council Institute of Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Crewe Road, Edinburgh, UK
| | - David Read
- Medical Research Council Human Genetics Unit, Medical Research Council Institute of Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Crewe Road, Edinburgh, UK
| | - Eleanor S. Raymond
- Medical Research Council Human Genetics Unit, Medical Research Council Institute of Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Crewe Road, Edinburgh, UK
| | - Chao-Chun Hung
- Medical Research Council Human Genetics Unit, Medical Research Council Institute of Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Crewe Road, Edinburgh, UK
| | - Shelagh Boyle
- Medical Research Council Human Genetics Unit, Medical Research Council Institute of Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Crewe Road, Edinburgh, UK
| | - Katsuhiko Shirahige
- Institute for Quantitative Biosciences, The University of Tokyo, Tokyo, Japan
| | - Howard J. Cooke
- Medical Research Council Human Genetics Unit, Medical Research Council Institute of Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Crewe Road, Edinburgh, UK
| | - Mary Herbert
- Institute for Genetic Medicine, Newcastle University, Biomedicine West Wing, Centre for Life, Newcastle upon Tyne, UK
- Newcastle Fertility Centre, Biomedicine West Wing, Centre for Life, Newcastle upon Tyne, UK
| | - Ian R. Adams
- Medical Research Council Human Genetics Unit, Medical Research Council Institute of Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Crewe Road, Edinburgh, UK
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Zielinska AP, Bellou E, Sharma N, Frombach AS, Seres KB, Gruhn JR, Blayney M, Eckel H, Moltrecht R, Elder K, Hoffmann ER, Schuh M. Meiotic Kinetochores Fragment into Multiple Lobes upon Cohesin Loss in Aging Eggs. Curr Biol 2019; 29:3749-3765.e7. [PMID: 31679939 PMCID: PMC6868511 DOI: 10.1016/j.cub.2019.09.006] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Revised: 07/23/2019] [Accepted: 09/04/2019] [Indexed: 01/02/2023]
Abstract
Chromosome segregation errors during female meiosis are a leading cause of pregnancy loss and human infertility. The segregation of chromosomes is driven by interactions between spindle microtubules and kinetochores. Kinetochores in mammalian oocytes are subjected to special challenges: they need to withstand microtubule pulling forces over multiple hours and are built on centromeric chromatin that in humans is decades old. In meiosis I, sister kinetochores are paired and oriented toward the same spindle pole. It is well established that they progressively separate from each other with advancing female age. However, whether aging also affects the internal architecture of centromeres and kinetochores is currently unclear. Here, we used super-resolution microscopy to study meiotic centromere and kinetochore organization in metaphase-II-arrested eggs from three mammalian species, including humans. We found that centromeric chromatin decompacts with advancing maternal age. Kinetochores built on decompacted centromeres frequently lost their integrity and fragmented into multiple lobes. Fragmentation extended across inner and outer kinetochore regions and affected over 30% of metaphase-II-arrested (MII) kinetochores in aged women and mice, making the lobular architecture a prominent feature of the female meiotic kinetochore. We demonstrate that a partial cohesin loss, as is known to occur in oocytes with advancing maternal age, is sufficient to trigger centromere decompaction and kinetochore fragmentation. Microtubule pulling forces further enhanced the fragmentation and shaped the arrangement of kinetochore lobes. Fragmented kinetochores were frequently abnormally attached to spindle microtubules, suggesting that kinetochore fragmentation could contribute to the maternal age effect in mammalian eggs.
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Affiliation(s)
- Agata P Zielinska
- Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, Göttingen 37077, Germany
| | - Eirini Bellou
- Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, Göttingen 37077, Germany
| | - Ninadini Sharma
- Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, Göttingen 37077, Germany
| | - Ann-Sophie Frombach
- Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, Göttingen 37077, Germany
| | - K Bianka Seres
- Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, Göttingen 37077, Germany; Bourn Hall Clinic, High Street, Cambridge CB23 2TN, UK
| | - Jennifer R Gruhn
- DNRF Center for Chromosome Stability, Department of Cellular and Molecular Medicine, University of Copenhagen, Blegdamsvej 3, Copenhagen DK-2200, Denmark
| | | | - Heike Eckel
- Kinderwunschzentrum, Kasseler Landstraße 25A, Göttingen 37081, Germany
| | - Rüdiger Moltrecht
- Kinderwunschzentrum, Kasseler Landstraße 25A, Göttingen 37081, Germany
| | - Kay Elder
- Bourn Hall Clinic, High Street, Cambridge CB23 2TN, UK
| | - Eva R Hoffmann
- DNRF Center for Chromosome Stability, Department of Cellular and Molecular Medicine, University of Copenhagen, Blegdamsvej 3, Copenhagen DK-2200, Denmark
| | - Melina Schuh
- Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, Göttingen 37077, Germany.
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Abstract
Chromosome segregation errors in human oocytes lead to aneuploid embryos that cause infertility and birth defects. Here we provide an overview of the chromosome-segregation process in the mammalian oocyte, highlighting mechanistic differences between oocytes and somatic cells that render oocytes so prone to segregation error. These differences include the extremely large size of the oocyte cytoplasm, the unique geometry of meiosis-I chromosomes, idiosyncratic function of the spindle assembly checkpoint, and dramatically altered oocyte cell-cycle control and spindle assembly, as compared to typical somatic cells. We summarise recent work suggesting that aging leads to a further deterioration in fidelity of chromosome segregation by impacting multiple components of the chromosome-segregation machinery. In addition, we compare and contrast recent results from mouse and human oocytes, which exhibit overlapping defects to differing extents. We conclude that the striking propensity of the oocyte to mis-segregate chromosomes reflects the unique challenges faced by the spindle in a highly unusual cellular environment.
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Affiliation(s)
- Aleksandar I Mihajlović
- Centre Recherche CHUM and Department OBGYN, Université de Montreal, Montreal, Quebec, Canada
| | - Greg FitzHarris
- Centre Recherche CHUM and Department OBGYN, Université de Montreal, Montreal, Quebec, Canada.
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42
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Kouznetsova A, Kitajima TS, Brismar H, Höög C. Post-metaphase correction of aberrant kinetochore-microtubule attachments in mammalian eggs. EMBO Rep 2019; 20:e47905. [PMID: 31290587 PMCID: PMC6680117 DOI: 10.15252/embr.201947905] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Revised: 05/24/2019] [Accepted: 06/07/2019] [Indexed: 12/29/2022] Open
Abstract
The accuracy of the two sequential meiotic divisions in oocytes is essential for creating a haploid gamete with a normal chromosomal content. Here, we have analysed the 3D dynamics of chromosomes during the second meiotic division in live mouse oocytes. We find that chromosomes form stable kinetochore-microtubule attachments at the end of prometaphase II stage that are retained until anaphase II onset. Remarkably, we observe that more than 20% of the kinetochore-microtubule attachments at the metaphase II stage are merotelic or lateral. However, < 1% of all chromosomes at onset of anaphase II are found to lag at the spindle equator and < 10% of the laggards missegregate and give rise to aneuploid gametes. Our results demonstrate that aberrant kinetochore-microtubule attachments are not corrected at the metaphase stage of the second meiotic division. Thus, the accuracy of the chromosome segregation process in mouse oocytes during meiosis II is ensured by an efficient correction process acting at the anaphase stage.
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Affiliation(s)
- Anna Kouznetsova
- Department of Cell and Molecular BiologyKarolinska InstitutetStockholmSweden
| | - Tomoya S Kitajima
- Laboratory for Chromosome SegregationRIKEN Center for Biosystems Dynamics ResearchKobeJapan
| | - Hjalmar Brismar
- Science for Life LaboratoryDepartment of Applied PhysicsRoyal Institute of TechnologySolnaSweden
| | - Christer Höög
- Department of Cell and Molecular BiologyKarolinska InstitutetStockholmSweden
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43
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Yun Y, Wei Z, Hunter N. Maternal obesity enhances oocyte chromosome abnormalities associated with aging. Chromosoma 2019; 128:413-421. [PMID: 31286204 DOI: 10.1007/s00412-019-00716-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2018] [Revised: 05/22/2019] [Accepted: 06/17/2019] [Indexed: 12/18/2022]
Abstract
Obesity is increasing globally, and maternal obesity has adverse effects on pregnancy outcomes and the long-term health of offspring. Maternal obesity has been associated with pregnancy failure through impaired oogenesis and embryogenesis. However, whether maternal obesity causes chromosome abnormalities in oocytes has remained unclear. Here we show that chromosome abnormalities are increased in the oocytes of obese mice fed a high-fat diet and identify weakened sister-chromatid cohesion as the likely cause. Numbers of full-grown follicles retrieved from obese mice were the same as controls and the efficiency of in vitro oocyte maturation remained high. However, chromosome abnormalities presenting in both metaphase-I and metaphase-II were elevated, most prominently the premature separation of sister chromatids. Weakened sister-chromatid cohesion in oocytes from obese mice was manifested both as the terminalization of chiasmata in metaphase-I and as increased separation of sister centromeres in metaphase II. Obesity-associated abnormalities were elevated in older mice implying that maternal obesity exacerbates the deterioration of cohesion seen with advancing age.
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Affiliation(s)
- Yan Yun
- Howard Hughes Medical Institute, University of California, Davis, Davis, CA, USA.,Department of Microbiology & Molecular Genetics, University of California, Davis, Davis, CA, USA
| | - Zijie Wei
- Department of Microbiology & Molecular Genetics, University of California, Davis, Davis, CA, USA
| | - Neil Hunter
- Howard Hughes Medical Institute, University of California, Davis, Davis, CA, USA. .,Department of Microbiology & Molecular Genetics, University of California, Davis, Davis, CA, USA. .,Department of Molecular & Cellular Biology, University of California, Davis, Davis, CA, USA. .,Department of Cell Biology & Human Anatomy, University of California, Davis, Davis, CA, USA.
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44
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Lee J. The Regulation and Function of Cohesin and Condensin in Mammalian Oocytes and Spermatocytes. Results Probl Cell Differ 2019; 63:355-372. [PMID: 28779325 DOI: 10.1007/978-3-319-60855-6_15] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Germ cells, such as oocytes and spermatocytes, produce haploid gametes by a special type of cell division called meiosis. The reduction of chromosome number is achieved in meiosis I, in which homologous chromosomes (homologs) are paired and recombined with their counterparts and finally segregated from each other. How meiotic chromosomes behave in a different manner from mitotic chromosomes has been a fascinating problem for cellular and developmental biology. Cohesin and condensin are multi-subunit protein complexes that play central roles in sister chromatid cohesion and chromosome condensation (also segregation), respectively. Recent studies investigating the expression and function of cohesin and condensin in mammalian germ cells greatly advance our understanding of the molecular mechanism underlying the meiotic chromosomal events. Furthermore, accumulating evidence suggests that reduction of cohesin during prophase I arrest in mammalian oocytes is one of the major causes for age-related chromosome segregation error. This review focuses on the regulation and functions of cohesins and condensins during mammalian meiosis.
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Affiliation(s)
- Jibak Lee
- Laboratory of Developmental Biotechnology, Graduate School of Agricultural Science, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe, 657-8501, Japan.
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45
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Shirasawa H, Ono N, Kumazawa Y, Sato W, Sato N, Ihara M, Yaegashi N, Terada Y. Oocyte collection and in vitro maturation after train transportation of human follicular fluid aspirated from resected non-stimulated ovaries of patients with endometrial adenocarcinoma. Reprod Med Biol 2019; 18:180-189. [PMID: 30996682 PMCID: PMC6452027 DOI: 10.1002/rmb2.12265] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Revised: 12/20/2018] [Accepted: 12/23/2018] [Indexed: 12/14/2022] Open
Abstract
PURPOSE Immature human oocytes from resected ovaries can be used for research and fertility preservation, though it is unknown whether it is feasible to transport oocytes for these purposes. This study examined in vitro maturation (IVM) outcomes after the transportation of human follicular fluid (HFF) containing oocytes. METHODS Fourteen patients with endometrial adenocarcinoma were enrolled. Oocytes obtained from the resected ovaries of seven patients were transported with HFF by railway (transportation group). Samples of HFF from the other seven patients were not transported, and IVM was performed promptly (non-transportation group). The results of oocyte retrieval and IVM were compared. RESULTS The average ages in the transportation and non-transportation groups were 40.1 ± 2.0 and 39.6 ± 1.8 years, respectively, and the average numbers of collected oocytes were 8.1 ± 8.4 and 5.1 ± 5.1, respectively. There was a significant negative correlation between the number of collected oocytes and age. The proportions of oocytes that reached meiosis II (maturation rate) after IVM were 38.6% and 69.2% in the transportation and non-transportation groups, respectively (P = 0.013). CONCLUSION In this preliminary study, the usefulness of the transportation of HFF was limited. Further studies on maintaining oocyte normality during transportation are necessary for becoming the effective method for research and clinical use.
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Affiliation(s)
- Hiromitsu Shirasawa
- Department of Obstetrics and GynecologyAkita University Graduate School of MedicineAkitaJapan
| | - Natsuki Ono
- Department of Obstetrics and GynecologyAkita University Graduate School of MedicineAkitaJapan
| | - Yukiyo Kumazawa
- Department of Obstetrics and GynecologyAkita University Graduate School of MedicineAkitaJapan
| | - Wataru Sato
- Department of Obstetrics and GynecologyAkita University Graduate School of MedicineAkitaJapan
| | - Naoki Sato
- Department of Obstetrics and GynecologyAkita University Graduate School of MedicineAkitaJapan
| | - Motomasa Ihara
- Department of Obstetrics and GynecologyTohoku University Graduate School of MedicineSendaiJapan
| | - Nobuo Yaegashi
- Department of Obstetrics and GynecologyTohoku University Graduate School of MedicineSendaiJapan
| | - Yukihiro Terada
- Department of Obstetrics and GynecologyAkita University Graduate School of MedicineAkitaJapan
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Pacchierotti F, Masumura K, Eastmond DA, Elhajouji A, Froetschl R, Kirsch-Volders M, Lynch A, Schuler M, Tweats D, Marchetti F. Chemically induced aneuploidy in germ cells. Part II of the report of the 2017 IWGT workgroup on assessing the risk of aneugens for carcinogenesis and hereditary diseases. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2019; 848:403023. [PMID: 31708072 DOI: 10.1016/j.mrgentox.2019.02.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Revised: 02/01/2019] [Accepted: 02/20/2019] [Indexed: 12/18/2022]
Abstract
As part of the 7th International Workshops on Genotoxicity Testing held in Tokyo, Japan in November 2017, a workgroup of experts reviewed and assessed the risk of aneugens for human health. The present manuscript is one of three manuscripts from the workgroup and reports on the unanimous consensus reached on the evidence for aneugens affecting germ cells, their mechanisms of action and role in hereditary diseases. There are 24 chemicals with strong or sufficient evidence for germ cell aneugenicity providing robust support for the ability of chemicals to induce germ cell aneuploidy. Interference with microtubule dynamics or inhibition of topoisomerase II function are clear characteristics of germ cell aneugens. Although there are mechanisms of chromosome segregation that are unique to germ cells, there is currently no evidence for germ cell-specific aneugens. However, the available data are heavily skewed toward chemicals that are aneugenic in somatic cells. Development of high-throughput screening assays in suitable animal models for exploring additional targets for aneuploidy induction, such as meiosis-specific proteins, and to prioritize chemicals for the potential to be germ cell aneugens is encouraged. Evidence in animal models support that: oocytes are more sensitive than spermatocytes and somatic cells to aneugens; exposure to aneugens leads to aneuploid conceptuses; and, the frequencies of aneuploidy are similar in germ cells and zygotes. Although aneuploidy in germ cells is a significant cause of infertility and pregnancy loss in humans, there is currently limited evidence that aneugens induce hereditary diseases in human populations because the great majority of aneuploid conceptuses die in utero. Overall, the present work underscores the importance of protecting the human population from exposure to chemicals that can induce aneuploidy in germ cells that, in contrast to carcinogenicity, is directly linked to an adverse outcome.
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Affiliation(s)
- Francesca Pacchierotti
- Health Protection Technology Division, Laboratory of Biosafety and Risk Assessment, ENEA, CR Casaccia, Rome, Italy
| | - Kenichi Masumura
- Division of Genetics and Mutagenesis, National Institute of Health Sciences, Kanagawa, Japan
| | - David A Eastmond
- Department of Molecular, Cell and System Biology, University of California, Riverside, CA, USA
| | - Azeddine Elhajouji
- Novartis Institutes for Biomedical Research, Preclinical Safety, Basel, Switzerland
| | | | - Micheline Kirsch-Volders
- Laboratory for Cell Genetics, Faculty of Sciences and Bio-Engineering, Vrije Universiteit Brussel, Brussels, Belgium
| | | | | | | | - Francesco Marchetti
- Environmental Health Science and Research Bureau, Health Canada, Ottawa, ON K1A 0K9, Canada.
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47
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Schneider I, Ellenberg J. Mysteries in embryonic development: How can errors arise so frequently at the beginning of mammalian life? PLoS Biol 2019; 17:e3000173. [PMID: 30840627 PMCID: PMC6422315 DOI: 10.1371/journal.pbio.3000173] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Revised: 03/18/2019] [Indexed: 12/21/2022] Open
Abstract
Chromosome segregation errors occur frequently during female meiosis but also in the first mitoses of mammalian preimplantation development. Such errors can lead to aneuploidy, spontaneous abortions, and birth defects. Some of the mechanisms underlying these errors in meiosis have been deciphered but which mechanisms could cause chromosome missegregation in the first embryonic cleavage divisions is mostly a “mystery”. In this article, we describe the starting conditions and challenges of these preimplantation divisions, which might impair faithful chromosome segregation. We also highlight the pending research to provide detailed insight into the mechanisms and regulation of preimplantation mitoses. Starting a new life is a challenging business. This Essay explores the changes at the oocyte-to-embryo transition to highlight the circumstances under which the very first and decisive — but ‘mysteriously’ error-prone — mitotic divisions occur.
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Affiliation(s)
- Isabell Schneider
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
- Candidate for joint PhD degree between EMBL and Heidelberg University, Faculty of Biosciences, Heidelberg, Germany
| | - Jan Ellenberg
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
- * E-mail:
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48
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Lane S, Kauppi L. Meiotic spindle assembly checkpoint and aneuploidy in males versus females. Cell Mol Life Sci 2019; 76:1135-1150. [PMID: 30564841 PMCID: PMC6513798 DOI: 10.1007/s00018-018-2986-6] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Revised: 11/12/2018] [Accepted: 12/03/2018] [Indexed: 12/13/2022]
Abstract
The production of gametes (sperm and eggs in mammals) involves two sequential cell divisions, meiosis I and meiosis II. In meiosis I, homologous chromosomes segregate to different daughter cells, and meiosis II resembles mitotic divisions in that sister chromatids separate. While in principle the process is identical in males and females, the time frame and susceptibility to chromosomal defects, including achiasmy and cohesion weakening, and the response to mis-segregating chromosomes are not. In this review, we compare and contrast meiotic spindle assembly checkpoint function and aneuploidy in the two sexes.
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Affiliation(s)
- Simon Lane
- Department of Chemistry and the Institute for Life Sciences, University of Southampton, Building 85, Highfield Campus, Southampton, SO171BJ, UK
| | - Liisa Kauppi
- Faculty of Medicine, University of Helsinki, Haartmaninkatu 8, 00014, Helsinki, Finland.
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Ishiguro K. The cohesin complex in mammalian meiosis. Genes Cells 2019; 24:6-30. [PMID: 30479058 PMCID: PMC7379579 DOI: 10.1111/gtc.12652] [Citation(s) in RCA: 76] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Revised: 10/29/2018] [Accepted: 10/29/2018] [Indexed: 12/13/2022]
Abstract
Cohesin is an evolutionary conserved multi-protein complex that plays a pivotal role in chromosome dynamics. It plays a role both in sister chromatid cohesion and in establishing higher order chromosome architecture, in somatic and germ cells. Notably, the cohesin complex in meiosis differs from that in mitosis. In mammalian meiosis, distinct types of cohesin complexes are produced by altering the combination of meiosis-specific subunits. The meiosis-specific subunits endow the cohesin complex with specific functions for numerous meiosis-associated chromosomal events, such as chromosome axis formation, homologue association, meiotic recombination and centromeric cohesion for sister kinetochore geometry. This review mainly focuses on the cohesin complex in mammalian meiosis, pointing out the differences in its roles from those in mitosis. Further, common and divergent aspects of the meiosis-specific cohesin complex between mammals and other organisms are discussed.
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Affiliation(s)
- Kei‐ichiro Ishiguro
- Institute of Molecular Embryology and GeneticsKumamoto UniversityKumamotoJapan
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Can peri-ovulatory putrescine supplementation improve egg quality in older infertile women? J Assist Reprod Genet 2018; 36:395-402. [PMID: 30467617 DOI: 10.1007/s10815-018-1327-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Accepted: 09/28/2018] [Indexed: 10/27/2022] Open
Abstract
The aging-related decline in fertility is an increasingly pressing medical and economic issue in modern society where women are delaying family building. Increasingly sophisticated, costly, and often increasingly invasive, assisted reproductive clinical protocols and laboratory technologies (ART) have helped many older women achieve their reproductive goals. Current ART procedures have not been able to address the fundamental problem of oocyte aging, the increased rate of egg aneuploidy, and the decline of developmental potential of the eggs. Oocyte maturation, which is triggered by luteinizing hormone (LH) in vivo or by injection of human chorionic gonadotropin (hCG) in an in vitro fertilization (IVF) clinic, is the critical stage at which the majority of egg aneuploidies arise and when much of an egg's developmental potential is established. Our proposed strategy focuses on improving egg quality in older women by restoring a robust oocyte maturation process. We have identified putrescine deficiency as one of the causes of poor egg quality in an aged mouse model. Putrescine is a biogenic polyamine naturally produced in peri-ovulatory ovaries. Peri-ovulatory putrescine supplementation has reduced egg aneuploidy, improved embryo quality, and reduced miscarriage rates in aged mice. In this paper, we review the literature on putrescine, its occurrence and physiology in living organisms, and its unique role in oocyte maturation. Preliminary human data demonstrates that there is a maternal aging-related deficiency in ovarian ornithine decarboxylase (ODC), the enzyme responsible for putrescine production. We argue that peri-ovulatory putrescine supplementation holds great promise as a natural and effective therapy for infertility in women of advanced maternal age, applicable in natural conception and in combination with current ART therapies.
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