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Abstract
Infertility is described as unexplained when pregnancy does not occur despite ovulation, patent Fallopian tubes, and normal semen parameters. Oocyte developmental competence (or quality) is rate-limiting for pregnancy success as oocytes provide virtually all the cellular building blocks including mitochondria required during embryogenesis. However, available tests estimate oocyte numbers (anti-Müllerian hormone, follicle-stimulating hormone and antral follicle count) and ovulation (luteal phase serum progesterone) but not the third, and most pivotal, oocyte-specific parameter, quality. Severe depletion of the follicular reserve manifests as premature ovarian insufficiency and is an obvious cause of anovulation with overt symptoms and clear diagnostic criteria. In contrast, there are no biomarkers of poor oocyte quality other than through in vitro fertilization when readouts of oocyte quality such as preimplantation embryo development can be assessed. The most common cause of poor oocyte quality is natural aging, which is strongly tied to reduced oocyte mitochondrial efficiency and increased oxidative stress. In younger women, quality may also be impaired due to accelerated aging or sporadic genetic mutations which cause severe defects during oocyte and embryo development. Thus, poor oocyte quality often provides an explanation for infertility, but because it cannot be measured using conventional tests, many cases of infertility are often incorrectly labeled "unexplained." Since female age remains the best predictor of oocyte quality, age over 37 years should be considered an independent diagnostic criterion.
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Affiliation(s)
- Hayden Anthony Homer
- Christopher Chen Oocyte Biology Research Laboratory, UQ Centre for Clinical Research, The University of Queensland, Brisbane, Herston 4029, Queensland, Australia
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52
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Saadeh K, Achercouk Z, Fazmin IT, Nantha Kumar N, Salvage SC, Edling CE, Huang CLH, Jeevaratnam K. Protein expression profiles in murine ventricles modeling catecholaminergic polymorphic ventricular tachycardia: effects of genotype and sex. Ann N Y Acad Sci 2020; 1478:63-74. [PMID: 32713021 DOI: 10.1111/nyas.14426] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 05/27/2020] [Accepted: 06/15/2020] [Indexed: 12/12/2022]
Abstract
Catecholaminergic polymorphic ventricular tachycardia (CPVT) is associated with mutations in the cardiac ryanodine receptor (RyR2). These result in stress-induced ventricular arrhythmic episodes, with clinical symptoms and prognosis reported more severe in male than female patients. Murine homozygotic RyR2-P2328S (RyR2S/S ) hearts replicate the proarrhythmic CPVT phenotype of abnormal sarcoplasmic reticular Ca2+ leak and disrupted Ca2+ homeostasis. In addition, RyR2S/S hearts show decreased myocardial action potential conduction velocities (CV), all features implicated in arrhythmic trigger and substrate. The present studies explored for independent and interacting effects of RyR2S/S genotype and sex on expression levels of molecular determinants of Ca2+ homeostasis (CASQ2, FKBP12, SERCA2a, NCX1, and CaV 1.2) and CV (NaV 1.5, Connexin (Cx)-43, phosphorylated-Cx43, and TGF-β1) in mice. Expression levels of Ca2+ homeostasis proteins were not altered, hence implicating abnormal RyR2 function alone in disrupted cytosolic Ca2+ homeostasis. Furthermore, altered NaV 1.5, phosphorylated Cx43, and TGF-β1 expression were not implicated in the development of slowed CV. By contrast, decreased Cx43 expression correlated with slowed CV, in female, but not male, RyR2S/S mice. The CV changes may reflect acute actions of the increased cytosolic Ca2+ on NaV 1.5 and Cx43 function.
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Affiliation(s)
- Khalil Saadeh
- Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom.,School of Clinical Medicine, Addenbrooke's Hospital, University of Cambridge, Cambridge, United Kingdom
| | - Zakaria Achercouk
- Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom
| | - Ibrahim T Fazmin
- Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom.,School of Clinical Medicine, Addenbrooke's Hospital, University of Cambridge, Cambridge, United Kingdom
| | - Nakulan Nantha Kumar
- Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom.,Bristol Medical School, University of Bristol, Bristol, United Kingdom
| | - Samantha C Salvage
- Physiological Laboratory, University of Cambridge, Cambridge, United Kingdom.,Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | - Charlotte E Edling
- Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom
| | - Christopher L-H Huang
- Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom.,Physiological Laboratory, University of Cambridge, Cambridge, United Kingdom.,Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | - Kamalan Jeevaratnam
- Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom.,Physiological Laboratory, University of Cambridge, Cambridge, United Kingdom
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53
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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: 126] [Impact Index Per Article: 31.5] [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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54
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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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55
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Abstract
We have previously presented a stereological analysis of organelle distribution in human prophase I oocytes. In the present study, using a similar stereological approach, we quantified the distribution of organelles in human metaphase I (MI) oocytes also retrieved after ovarian stimulation. Five MI oocytes were processed for transmission electron microscopy and a classical manual stereological technique based on point-counting with an adequate stereological grid was used. Kruskal-Wallis and Mann-Whitney U-tests with Bonferroni correction were used to compare the means of relative volumes (Vv) occupied by organelles. In all oocyte regions, the most abundant organelles were mitochondria and smooth endoplasmic reticulum (SER) elements. No significant differences were observed in Vv of mitochondria, dictyosomes, lysosomes, or SER small and medium vesicles, tubular aggregates and tubules. Significant differences were observed in other organelle distributions: cortical vesicles presented a higher Vv (P = 0.004) in the cortex than in the subcortex (0.96% vs 0.1%) or inner cytoplasm (0.96% vs 0.1%), vesicles with dense granular contents had a higher Vv (P = 0.005) in the cortex than in the subcortex (0.1% vs 0%), and SER large vesicles exhibited a higher Vv (P = 0.011) in the inner cytoplasm than in the subcortex (0.2% vs 0%). Future stereological analysis of metaphase II oocytes and a combined quantitative data of mature and immature oocytes, will enable a better understanding of oocyte organelle distribution during in vivo maturation. Combined with molecular approaches, this may help improve stimulation protocols and in vitro maturation methods.
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56
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Rémillard-Labrosse G, Dean NL, Allais A, Mihajlović AI, Jin SG, Son WY, Chung JT, Pansera M, Henderson S, Mahfoudh A, Steiner N, Agapitou K, Marangos P, Buckett W, Ligeti-Ruiter J, FitzHarris G. Human oocytes harboring damaged DNA can complete meiosis I. Fertil Steril 2020; 113:1080-1089.e2. [PMID: 32276763 DOI: 10.1016/j.fertnstert.2019.12.029] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Revised: 12/19/2019] [Accepted: 12/20/2019] [Indexed: 10/24/2022]
Abstract
OBJECTIVE To determine whether human oocytes possess a checkpoint to prevent completion of meiosis I when DNA is damaged. DESIGN DNA damage is considered a major threat to the establishment of healthy eggs and embryos. Recent studies found that mouse oocytes with damaged DNA can resume meiosis and undergo germinal vesicle breakdown (GVBD), but then arrest in metaphase of meiosis I in a process involving spindle assembly checkpoint (SAC) signaling. Such a mechanism could help prevent the generation of metaphase II (MII) eggs with damaged DNA. Here, we compared the impact of DNA-damaging agents with nondamaged control samples in mouse and human oocytes. SETTING University-affiliated clinic and research center. PATIENT(S) Patients undergoing ICSI cycles donated GV-stage oocytes after informed consent; 149 human oocytes were collected over 2 years (from 50 patients aged 27-44 years). INTERVENTIONS(S) Mice and human oocytes were treated with DNA-damaging drugs. MAIN OUTCOME MEASURE(S) Oocytes were monitored to evaluate GVBD and polar body extrusion (PBE), in addition to DNA damage assessment with the use of γH2AX antibodies and confocal microscopy. RESULT(S) Whereas DNA damage in mouse oocytes delays or prevents oocyte maturation, most human oocytes harboring experimentally induced DNA damage progress through meiosis I and subsequently form an MII egg, revealing the absence of a DNA damage-induced SAC response. Analysis of the resulting MII eggs revealed damaged DNA and chaotic spindle apparatus, despite the oocyte appearing morphologically normal. CONCLUSION(S) Our data indicate that experimentally induced DNA damage does not prevent PBE in human oocytes and can persist in morphologically normal looking MII eggs.
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Affiliation(s)
| | - Nicola L Dean
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal, Montreal, Quebec, Canada
| | - Adélaïde Allais
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal, Montreal, Quebec, Canada
| | - Aleksandar I Mihajlović
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal, Montreal, Quebec, Canada; Département d'Obstétrique-Gynécologie, Université de Montréal, Montreal, Quebec, Canada
| | - Shao Guang Jin
- Reproductive Centre, McGill University Health Centre, Montreal, Quebec, Canada
| | - Weon-Young Son
- Reproductive Centre, McGill University Health Centre, Montreal, Quebec, Canada
| | - Jin-Tae Chung
- Reproductive Centre, McGill University Health Centre, Montreal, Quebec, Canada
| | - Melissa Pansera
- Reproductive Centre, McGill University Health Centre, Montreal, Quebec, Canada
| | - Sara Henderson
- Reproductive Centre, McGill University Health Centre, Montreal, Quebec, Canada
| | - Alina Mahfoudh
- Reproductive Centre, McGill University Health Centre, Montreal, Quebec, Canada
| | - Naama Steiner
- Reproductive Centre, McGill University Health Centre, Montreal, Quebec, Canada
| | - Kristy Agapitou
- Department of Applications and Technology, University of Ioannina, Ioannina, Greece; Institute of Life Fertility Unit, IASO Maternity Hospital, Athens, Greece
| | - Petros Marangos
- Department of Applications and Technology, University of Ioannina, Ioannina, Greece; Department of Biomedical Research, Institute of Molecular Biology and Biotechnology-Foundation for Research and Technology, Ioannina, Greece
| | - William Buckett
- Reproductive Centre, McGill University Health Centre, Montreal, Quebec, Canada
| | - Jacob Ligeti-Ruiter
- Reproductive Centre, McGill University Health Centre, Montreal, Quebec, Canada
| | - Greg FitzHarris
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal, Montreal, Quebec, Canada; Département d'Obstétrique-Gynécologie, Université de Montréal, Montreal, Quebec, Canada.
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57
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Chromosome Missegregation in Single Human Oocytes Is Related to the Age and Gene Expression Profile. Int J Mol Sci 2020; 21:ijms21061934. [PMID: 32178390 PMCID: PMC7139522 DOI: 10.3390/ijms21061934] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Revised: 03/09/2020] [Accepted: 03/10/2020] [Indexed: 12/16/2022] Open
Abstract
The growing trend for women to postpone childbearing has resulted in a dramatic increase in the incidence of aneuploid pregnancies. Despite the importance to human reproductive health, the events precipitating female age-related meiotic errors are poorly understood. To gain new insight into the molecular basis of age-related chromosome missegregation in human oocytes, we combined the transcriptome profiles of twenty single oocytes (derived from females divided into two groups according to age <35 and ≥35 years) with their chromosome status obtained by array comparative genomic hybridization (aCGH). Furthermore, we compared the transcription profile of the single oocyte with the surrounding cumulus cells (CCs). RNA-seq data showed differences in gene expression between young and old oocytes. Dysregulated genes play a role in important biological processes such as gene transcription regulation, cytoskeleton organization, pathways related to RNA maturation and translation. The comparison of the transcription profile of the oocyte and the corresponding CCs highlighted the differential expression of genes belonging to the G protein-coupled receptor superfamily. Finally, we detected the loss of a X chromosome in two oocytes derived from women belonging to the ≥35 years age group. These aneuploidies may be caused by the detriment of REEP4, an endoplasmic reticulum protein, in women aged ≥35 years. Here we gained new insight into the complex regulatory circuit between the oocyte and the surrounding CCs and uncovered a new putative molecular basis of age-related chromosome missegregation in human oocytes.
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58
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Chiaratti MR, Macabelli CH, Augusto Neto JD, Grejo MP, Pandey AK, Perecin F, Collado MD. Maternal transmission of mitochondrial diseases. Genet Mol Biol 2020; 43:e20190095. [PMID: 32141474 PMCID: PMC7197987 DOI: 10.1590/1678-4685-gmb-2019-0095] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Accepted: 11/01/2019] [Indexed: 12/19/2022] Open
Abstract
Given the major role of the mitochondrion in cellular homeostasis, dysfunctions of this organelle may lead to several common diseases in humans. Among these, maternal diseases linked to mitochondrial DNA (mtDNA) mutations are of special interest due to the unclear pattern of mitochondrial inheritance. Multiple copies of mtDNA are present in a cell, each encoding for 37 genes essential for mitochondrial function. In cases of mtDNA mutations, mitochondrial malfunctioning relies on mutation load, as mutant and wild-type molecules may co-exist within the cell. Since the mutation load associated with disease manifestation varies for different mutations and tissues, it is hard to predict the progeny phenotype based on mutation load in the progenitor. In addition, poorly understood mechanisms act in the female germline to prevent the accumulation of deleterious mtDNA in the following generations. In this review, we outline basic aspects of mitochondrial inheritance in mammals and how they may lead to maternally-inherited diseases. Furthermore, we discuss potential therapeutic strategies for these diseases, which may be used in the future to prevent their transmission.
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Affiliation(s)
- Marcos R Chiaratti
- Universidade Federal de São Carlos, Departamento de Genética e Evolução, Laboratório de Genética e Biotecnologia, São Carlos, SP, Brazil
| | - Carolina H Macabelli
- Universidade Federal de São Carlos, Departamento de Genética e Evolução, Laboratório de Genética e Biotecnologia, São Carlos, SP, Brazil
| | - José Djaci Augusto Neto
- Universidade Federal de São Carlos, Departamento de Genética e Evolução, Laboratório de Genética e Biotecnologia, São Carlos, SP, Brazil
| | - Mateus Priolo Grejo
- Universidade Federal de São Carlos, Departamento de Genética e Evolução, Laboratório de Genética e Biotecnologia, São Carlos, SP, Brazil
| | - Anand Kumar Pandey
- Lala Lajpat Rai University of Veterinary and Animal Sciences, Hisar, Haryana, India
| | - Felipe Perecin
- Universidade de São Paulo, Faculdade de Zootecnia e Engenharia de Alimentos, Departamento de Medicina Veterinária, Laboratório de Morfofisiologia Molecular e Desenvolvimento, Pirassununga, SP, Brazil
| | - Maite Del Collado
- Universidade de São Paulo, Faculdade de Zootecnia e Engenharia de Alimentos, Departamento de Medicina Veterinária, Laboratório de Morfofisiologia Molecular e Desenvolvimento, Pirassununga, SP, Brazil
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59
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Peng R, Wang L, Gao W, Zhu F, Hu F, Zeng W, Shi L, Chen X, Cai J, Zhang D, Xia Z, Yang Z. The 5.8S pre-rRNA maturation factor, M-phase phosphoprotein 6, is a female fertility factor required for oocyte quality and meiosis. Cell Prolif 2020; 53:e12769. [PMID: 32003502 PMCID: PMC7106954 DOI: 10.1111/cpr.12769] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2019] [Revised: 12/07/2019] [Accepted: 01/04/2020] [Indexed: 11/30/2022] Open
Abstract
OBJECTIVES M-phase phosphoprotein 6 (MPP6) is important for 5.8S pre-rRNA maturation in somatic cells and was screened as a female fertility factor. However, whether MPP6 functions in oocyte meiosis and fertility is not yet known. We aimed to address this. MATERIALS AND METHODS Mouse oocytes with surrounded nucleus (SN) or non-surrounded nucleus (NSN) were used for all experiments. Peptide nanoparticle-mediated antibody transfection was used to deplete MPP6. Immunofluorescence staining, immunohistochemistry and live tracker staining were used to examine MPP6 localization and characterize phenotypes after control or MPP6 depletion. High-fidelity PCR and fluorescence in situ hybridization (FISH) were used to examine the localization and level of 5.8S rRNAs. Western blot was used to examine the protein level. MPP6-EGFP mRNA microinjection was used to do the rescue. RESULTS MPP6 was enriched within ovaries and oocytes. MPP6 depletion significantly impeded oocyte meiosis. MPP6 depletion increased 5.8S pre-rRNA. The mRNA levels of MPP6 and 5.8S rRNA decreased within ageing oocytes, and MPP6 mRNA injection partially increased 5.8S rRNA maturation and improved oocyte quality. CONCLUSIONS MPP6 is required for 5.8S rRNA maturation, meiosis and quality control in mouse oocytes, and MPP6 level might be a marker for oocyte quality.
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Affiliation(s)
- Rui‐Rui Peng
- Center for Reproductive MedicineShandong Provincial Hospital Affiliated to Shandong UniversityJinanChina
- State Key Lab of Reproductive MedicineNanjing Medical UniversityNanjingChina
| | - Li‐Li Wang
- State Key Lab of Reproductive MedicineNanjing Medical UniversityNanjingChina
| | - Wen‐Yi Gao
- State Key Lab of Reproductive MedicineNanjing Medical UniversityNanjingChina
| | - Feng‐Yu Zhu
- State Key Lab of Reproductive MedicineNanjing Medical UniversityNanjingChina
| | - Fan Hu
- State Key Lab of Reproductive MedicineNanjing Medical UniversityNanjingChina
| | - Wen‐Tao Zeng
- Animal Core FacilityNanjing Medical UniversityNanjingChina
| | - Li‐Ya Shi
- The Second Affiliated HospitalNanjing Medical UniversityNanjingChina
| | - Xi‐Chen Chen
- Analysis and Test CenterNanjing Medical UniversityNanjingChina
| | - Jing‐Yang Cai
- State Key Lab of Reproductive MedicineNanjing Medical UniversityNanjingChina
| | - Dong Zhang
- State Key Lab of Reproductive MedicineNanjing Medical UniversityNanjingChina
- Animal Core FacilityNanjing Medical UniversityNanjingChina
| | - Zheng‐Rong Xia
- Analysis and Test CenterNanjing Medical UniversityNanjingChina
| | - Zhi‐Xia Yang
- State Key Lab of Reproductive MedicineNanjing Medical UniversityNanjingChina
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60
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Astbury P, Subramanian GN, Greaney J, Roling C, Irving J, Homer HA. The Presence of Immature GV- Stage Oocytes during IVF/ICSI Is a Marker of Poor Oocyte Quality: A Pilot Study. Med Sci (Basel) 2020; 8:medsci8010004. [PMID: 31963146 PMCID: PMC7151566 DOI: 10.3390/medsci8010004] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Revised: 01/06/2020] [Accepted: 01/13/2020] [Indexed: 12/13/2022] Open
Abstract
Here we investigate whether the presence of germinal vesicle-stage oocytes (GV- oocytes) reflects poor oocyte developmental competence (or quality). This was a prospective, non-randomised, cohort pilot-study involving 60 patients undergoing in vitro fertilization/ intracytoplasmic sperm injection for whom complete pregnancy outcome data were available. Patients in whom GV- oocytes were retrieved (GV+) at transvaginal oocyte retrieval (TVOR) were compared with those from whom no GVs were retrieved (GV-). We found that GV+ (n = 29) and GV- (n = 31) patients were similarly aged (35.4 vs. 36.4 years; p = 0.446). GV+ patients had a mean of 2.41 ± 2.03 GVs and comparable yields of MII oocytes to GV- patients (11 ± 6.88 vs. 8.26 ± 4.84; p = 0.077). Compared with GV- patients, GV+ patients had markedly lower implantation rates (11.8% vs. 30.2%; p = 0.022) as well as oocyte utilisation rates for clinical pregnancy (2.3% vs. 6.8%; p = 0.018) and live-birth (1.9% vs. 5.7%; p = 0.029). DNA damage levels measured using γH2AX immunostaining were not different in oocytes from women <36 years versus those ≥36 years (p = 0.606). Thus, patients who have GV- stage oocytes at TVOR exhibit poor oocyte quality reflected in reduced per-oocyte pregnancy success rates and uniformly high levels of oocyte DNA damage.
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Affiliation(s)
- Pia Astbury
- Christopher Chen Oocyte Biology Research Laboratory, UQ Centre for Clinical Research, The University of Queensland, Herston 4029, Queensland, Australia
- Queensland Fertility Group, Brisbane 4000, Queensland, Australia
| | - Goutham N. Subramanian
- Christopher Chen Oocyte Biology Research Laboratory, UQ Centre for Clinical Research, The University of Queensland, Herston 4029, Queensland, Australia
| | - Jessica Greaney
- Christopher Chen Oocyte Biology Research Laboratory, UQ Centre for Clinical Research, The University of Queensland, Herston 4029, Queensland, Australia
| | - Chris Roling
- Queensland Fertility Group, Brisbane 4000, Queensland, Australia
| | - Jacqui Irving
- Queensland Fertility Group, Brisbane 4000, Queensland, Australia
| | - Hayden A. Homer
- Christopher Chen Oocyte Biology Research Laboratory, UQ Centre for Clinical Research, The University of Queensland, Herston 4029, Queensland, Australia
- Queensland Fertility Group, Brisbane 4000, Queensland, Australia
- Reproductive Endocrinology & Infertility Clinic, Royal Brisbane & Women’s Hospital, Brisbane 4029, Queensland, Australia
- Correspondence:
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61
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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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62
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Design of Warship Simulation Using Variable-Chromosome Genetic Algorithm. APPLIED SCIENCES-BASEL 2019. [DOI: 10.3390/app9194131] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
A genetic algorithm (GA) is a global search algorithm based on biological genetics. GAs are generally used for industrial applications, artificial neural networks, web applications, the defense industry, and so on. However, it is difficult to apply GAs to more complex situations because of the fixed number of chromosomes. In this research, in order to overcome this limitation, we propose a variable-chromosome GA with a chromosome attachment feature. Verification of the algorithm is carried out through anti-submarine high value unit (HVU) escort mission simulations. Ultimately, it is confirmed that the GA using the variable chromosome is more effective in dealing with highly complex missions, whereby the number of chromosomes gradually increases.
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63
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Wang S, Liu Y, Shang Y, Zhai B, Yang X, Kleckner N, Zhang L. Crossover Interference, Crossover Maturation, and Human Aneuploidy. Bioessays 2019; 41:e1800221. [PMID: 31424607 PMCID: PMC6756933 DOI: 10.1002/bies.201800221] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Revised: 07/23/2019] [Indexed: 12/12/2022]
Abstract
A striking feature of human female sexual reproduction is the high level of gametes that exhibit an aberrant number of chromosomes (aneuploidy). A high baseline observed in women of prime reproductive age is followed by a dramatic increase in older women. Proper chromosome segregation requires one or more DNA crossovers (COs) between homologous maternal and paternal chromosomes, in combination with cohesion between sister chromatid arms. In human females, CO designations occur normally, according to the dictates of CO interference, giving early CO-fated intermediates. However, ≈25% of these intermediates fail to mature to final CO products. This effect explains the high baseline of aneuploidy and is predicted to synergize with age-dependent cohesion loss to explain the maternal age effect. Here, modern advances in the understanding of crossing over and CO interference are reviewed, the implications of human female CO maturation inefficiency are further discussed, and areas of interest for future studies are suggested.
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Affiliation(s)
- Shunxin Wang
- Center for Reproductive Medicine, Shandong University, National Research Center for Assisted Reproductive Technology and Reproductive Genetics, Key Laboratory of Reproductive Endocrinology of Ministry of Education, Jinan, Shandong 250001, China
| | - Yanlei Liu
- Center for Reproductive Medicine, Shandong University, National Research Center for Assisted Reproductive Technology and Reproductive Genetics, Key Laboratory of Reproductive Endocrinology of Ministry of Education, Jinan, Shandong 250001, China
| | - Yongliang Shang
- Center for Reproductive Medicine, Shandong University, National Research Center for Assisted Reproductive Technology and Reproductive Genetics, Key Laboratory of Reproductive Endocrinology of Ministry of Education, Jinan, Shandong 250001, China
| | - Binyuan Zhai
- Center for Reproductive Medicine, Shandong University, National Research Center for Assisted Reproductive Technology and Reproductive Genetics, Key Laboratory of Reproductive Endocrinology of Ministry of Education, Jinan, Shandong 250001, China
| | - Xiao Yang
- Center for Reproductive Medicine, Shandong University, National Research Center for Assisted Reproductive Technology and Reproductive Genetics, Key Laboratory of Reproductive Endocrinology of Ministry of Education, Jinan, Shandong 250001, China
| | - Nancy Kleckner
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, USA
| | - Liangran Zhang
- Center for Reproductive Medicine, Shandong University, National Research Center for Assisted Reproductive Technology and Reproductive Genetics, Key Laboratory of Reproductive Endocrinology of Ministry of Education, Jinan, Shandong 250001, China
- Advanced Medical Research Institute, Shandong University, Jinan, China
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China
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Zhou C, Hancock JL, Khanna KK, Homer HA. First meiotic anaphase requires Cep55-dependent inhibitory cyclin-dependent kinase 1 phosphorylation. J Cell Sci 2019; 132:jcs.233379. [PMID: 31427428 DOI: 10.1242/jcs.233379] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Accepted: 08/09/2019] [Indexed: 12/28/2022] Open
Abstract
During mitosis, anaphase is triggered by anaphase-promoting complex (APC)-mediated destruction of securin and cyclin B1, which leads to inactivation of cyclin-dependent kinase 1 (Cdk1). By regulating APC activity, the mitotic spindle assembly checkpoint (SAC) therefore has robust control over anaphase timing to prevent chromosome mis-segregation. Mammalian oocytes are prone to aneuploidy, the reasons for which remain obscure. In mitosis, Cep55 is required post-anaphase for the final steps of cytokinesis. We found that Cep55-depleted mouse oocytes progress normally through early meiosis I, but that anaphase I fails as a result of persistent Cdk1 activity. Unexpectedly, Cdk1 inactivation was compromised following Cep55 depletion, despite on-time SAC silencing and intact APC-mediated proteolysis. We found that impaired Cdk1 inactivation was caused by inadequate inhibitory Cdk1 phosphorylation consequent upon failure to suppress Cdc25 phosphatase, identifying a proteolysis-independent step necessary for anaphase I. Thus, the SAC in oocytes does not exert exclusive control over anaphase I initiation, providing new insight into vulnerability to error.
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Affiliation(s)
- Chenxi Zhou
- The Christopher Chen Oocyte Biology Research Laboratory, UQ Centre for Clinical Research, The University of Queensland, Herston 4029, QLD, Australia
| | - Janelle L Hancock
- Signal Transduction Laboratory, QIMR Berghofer Medical Research Institute, Herston, QLD, Australia
| | - Kum Kum Khanna
- Signal Transduction Laboratory, QIMR Berghofer Medical Research Institute, Herston, QLD, Australia
| | - Hayden A Homer
- The Christopher Chen Oocyte Biology Research Laboratory, UQ Centre for Clinical Research, The University of Queensland, Herston 4029, QLD, Australia
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Gatinois V, Bigi N, Mousty E, Chiesa J, Musizzano Y, Schneider A, Lefort G, Pinson L, Gaillard JB, Ragon C, Perez MJ, Tournaire M, Blanchet P, Corsini C, Haquet E, Callier P, Geneviève D, Pellestor F, Puechberty J. Mosaic complete tetrasomy 21 in a fetus with complete atrioventricular septal defect and minor morphological variations. Mol Genet Genomic Med 2019; 7:e00895. [PMID: 31493343 PMCID: PMC6825868 DOI: 10.1002/mgg3.895] [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: 01/21/2019] [Revised: 05/02/2019] [Accepted: 07/17/2019] [Indexed: 11/22/2022] Open
Abstract
Background Tetrasomy 21 is a very rare aneuploidy which could clinically resemble a Down syndrome. It was most often described in its partial form than complete. We report the prenatal, pathological and genetic characteristics of a fetus with mosaic complete tetrasomy 21. This is the second well‐documented description of a complete tetrasomy 21 in the literature. Methods Prenatal and fetal pathological examinations, cytogenetic and molecular analyses were performed to characterize fetal features with tetrasomy 21. Results Prenatal ultrasound examination revealed an isolated complete atrioventricular septal defect with normal karyotype on amniotic fluid. After termination of pregnancy, clinical examination of the fetus evoked trisomy 21 or Down syndrome. Chromosomal microarray analysis and FISH on lung tissue showed a mosaicism with four copies of chromosome 21 (tetrasomy 21). Conclusion Our observation and the review of the literature reported the possibility of very weak mosaicism and disease‐causing confined tissue‐specific mosaicism in fetus or alive patients with chromosome 21 aneuploidy, mainly Down syndrome. In case of clinical diagnosis suggestive of Down syndrome, attention must be paid to the risk of false‐negative test due to chromosomal mosaicism (very weak percentage, different tissue distribution). To overcome this risk, it is necessary to privilege the diagnostic techniques without culture step and to increase the number of cells and tissues analyzed, if possible. This study highlights the limits of microarray as the unique diagnostic approach in case of weak mosaic and French cytogenetics guidelines recommend to check anomalies seen in microarray by another technique on the same tissue.
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Affiliation(s)
- Vincent Gatinois
- Laboratoire de Génétique Chromosomique, Hôpital Arnaud de Villeneuve, CHU de Montpellier, Montpellier, France
| | - Nicole Bigi
- Service de Génétique Clinique, Département de Génétique Médicale, Maladies Rares et Médecine Personnalisée, Hôpital Arnaud de Villeneuve, CHU de Montpellier, Montpellier, France
| | - Eve Mousty
- Département de Gynécologie-Obstétrique, Hôpital Carémeau, CHU de Nîmes, Nîmes, France
| | - Jean Chiesa
- Laboratoire de Cytologie Clinique et Cytogénétique, Hôpital Carémeau, CHU de Nîmes, Nîmes, France
| | - Yuri Musizzano
- Laboratoire d'Anatomie et Cytologie Pathologique, Hôpital Gui-de-Chauliac, CHU de Montpellier, Montpellier, France
| | - Anouck Schneider
- Laboratoire de Génétique Chromosomique, Hôpital Arnaud de Villeneuve, CHU de Montpellier, Montpellier, France
| | - Geneviève Lefort
- Laboratoire de Génétique Chromosomique, Hôpital Arnaud de Villeneuve, CHU de Montpellier, Montpellier, France
| | - Lucile Pinson
- Service de Génétique Clinique, Département de Génétique Médicale, Maladies Rares et Médecine Personnalisée, Hôpital Arnaud de Villeneuve, CHU de Montpellier, Montpellier, France
| | - Jean-Baptiste Gaillard
- Laboratoire de Génétique Chromosomique, Hôpital Arnaud de Villeneuve, CHU de Montpellier, Montpellier, France.,Laboratoire de Cytologie Clinique et Cytogénétique, Hôpital Carémeau, CHU de Nîmes, Nîmes, France
| | - Clémence Ragon
- Laboratoire de Génétique Moléculaire et Cytogénétique, Hôpital du Bocage, CHU de Dijon, Dijon, France
| | - Marie-Josée Perez
- Service de Génétique Clinique, Département de Génétique Médicale, Maladies Rares et Médecine Personnalisée, Hôpital Arnaud de Villeneuve, CHU de Montpellier, Montpellier, France
| | - Magali Tournaire
- Laboratoire de Génétique Chromosomique, Hôpital Arnaud de Villeneuve, CHU de Montpellier, Montpellier, France
| | - Patricia Blanchet
- Service de Génétique Clinique, Département de Génétique Médicale, Maladies Rares et Médecine Personnalisée, Hôpital Arnaud de Villeneuve, CHU de Montpellier, Montpellier, France
| | - Carole Corsini
- Service de Génétique Clinique, Département de Génétique Médicale, Maladies Rares et Médecine Personnalisée, Hôpital Arnaud de Villeneuve, CHU de Montpellier, Montpellier, France
| | - Emmanuelle Haquet
- Service de Génétique Clinique, Département de Génétique Médicale, Maladies Rares et Médecine Personnalisée, Hôpital Arnaud de Villeneuve, CHU de Montpellier, Montpellier, France
| | - Patrick Callier
- Laboratoire de Génétique Moléculaire et Cytogénétique, Hôpital du Bocage, CHU de Dijon, Dijon, France
| | - David Geneviève
- Service de Génétique Clinique, Département de Génétique Médicale, Maladies Rares et Médecine Personnalisée, Hôpital Arnaud de Villeneuve, CHU de Montpellier, Montpellier, France
| | - Franck Pellestor
- Laboratoire de Génétique Chromosomique, Hôpital Arnaud de Villeneuve, CHU de Montpellier, Montpellier, France
| | - Jacques Puechberty
- Service de Génétique Clinique, Département de Génétique Médicale, Maladies Rares et Médecine Personnalisée, Hôpital Arnaud de Villeneuve, CHU de Montpellier, Montpellier, France
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Homer HA. Preimplantation genetic testing for aneuploidy (PGT-A): The biology, the technology and the clinical outcomes. Aust N Z J Obstet Gynaecol 2019; 59:317-324. [PMID: 30811595 DOI: 10.1111/ajo.12960] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Accepted: 01/02/2019] [Indexed: 11/29/2022]
Abstract
Preimplantation genetic testing for aneuploidy (PGT-A) seeks to identify preimplantation embryos with a normal chromosome complement (euploid) during in vitro fertilisation (IVF). By sifting out embryos with abnormal chromosome numbers (aneuploid), PGT-A should theoretically improve pregnancy success. However, earlier versions of PGT-A were ineffective, and in some cases, detrimental, due to biopsy-induced trauma and because the technology at the time could analyse only a fraction of all chromosomes. More recently, the emergence of technologies enabling all chromosomes to be analysed and a switch to less traumatic blastocyst-stage biopsy have seen widespread uptake of PGT-A. Assessing the full impact of blastocyst biopsy PGT-A requires consideration of multiple factors, including embryonic mosaicism, sensitivity of the technological platform used, embryo loss during long-term in vitro culture, embryo cryopreservation and inter-clinic variability in expertise. Significantly, there hasnt yet been an appropriately designed randomised controlled trial (RCT) of blastocyst biopsy PGT-A analysed by intention-to-treat that accounts for all these parameters on a per-cycle basis. The three RCTs reporting benefits studied outcomes on a per-embryo transfer basis were small and underpowered and demonstrated benefits for a very select sub-group of good prognosis patients. The liberal use of this very expensive IVF add-on for other patient populations has not yet been shown to be effective, or indeed, without harm.
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Affiliation(s)
- Hayden Anthony Homer
- Christopher Chen Oocyte Biology Research Laboratory, UQ Centre for Clinical Research, The University of Queensland, Brisbane, Queensland, Australia.,Reproductive Endocrinology and Infertility Clinic, Royal Brisbane & Women's Hospital, Brisbane, Queensland, Australia.,Queensland Fertility Group, Brisbane, Queensland, Australia
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67
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Lin Y, Yang P, Chen Y, Zhu J, Zhang X, Ma C. Factors inducing decreased oocyte maturation rate: a retrospective analysis of 20,939 ICSI cycles. Arch Gynecol Obstet 2019; 299:559-564. [DOI: 10.1007/s00404-018-4958-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2018] [Accepted: 10/26/2018] [Indexed: 01/24/2023]
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Kirsch-Volders M, Pacchierotti F, Parry EM, Russo A, Eichenlaub-Ritter U, Adler ID. Risks of aneuploidy induction from chemical exposure: Twenty years of collaborative research in Europe from basic science to regulatory implications. MUTATION RESEARCH-REVIEWS IN MUTATION RESEARCH 2018; 779:126-147. [PMID: 31097149 DOI: 10.1016/j.mrrev.2018.11.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 11/26/2018] [Indexed: 12/13/2022]
Abstract
Although Theodor Boveri linked abnormal chromosome numbers and disease more than a century ago, an in-depth understanding of the impact of mitotic and meiotic chromosome segregation errors on cell proliferation and diseases is still lacking. This review reflects on the efforts and results of a large European research network that, from the 1980's until 2004, focused on protection against aneuploidy-inducing factors and tackled the following problems: 1) the origin and consequences of chromosome imbalance in somatic and germ cells; 2) aneuploidy as a result of environmental factors; 3) dose-effect relationships; 4) the need for validated assays to identify aneugenic factors and classify them according to their modes of action; 5) the need for reliable, quantitative data suitable for regulating exposure and preventing aneuploidy induction; 6) the need for mechanistic insight into the consequences of aneuploidy for human health. This activity brought together a consortium of experts from basic science and applied genetic toxicology to prepare the basis for defining guidelines and to encourage regulatory activities for the prevention of induced aneuploidy. Major strengths of the EU research programmes on aneuploidy were having a valuable scientific approach based on well-selected compounds and accurate methods that allow the determination of precise dose-effect relationships, reproducibility and inter-laboratory comparisons. The work was conducted by experienced scientists stimulated by a fascination with the complex scientific issues surrounding aneuploidy; a key strength was asking the right questions at the right time. The strength of the data permitted evaluation at the regulatory level. Finally, the entire enterprise benefited from a solid partnership under the lead of an inspired and stimulating coordinator. The research programme elucidated the major modes of action of aneugens, developed scientifically sound assays to assess aneugens in different tissues, and achieved the international validation of relevant assays with the goal of protecting human populations from aneugenic chemicals. The role of aneuploidy in tumorigenesis will require additional research, and the study of effects of exposure to multiple agents should become a priority. It is hoped that these reflections will stimulate the implementation of aneuploidy testing in national and OECD guidelines.
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Affiliation(s)
- Micheline Kirsch-Volders
- Laboratory for Cell Genetics, Faculty of Sciences and Bioengineering, Vrije Universiteit Brussel, Brussels, Belgium.
| | | | | | - Antonella Russo
- Department of Molecular Medicine, University of Padova, Padova, Italy
| | - Ursula Eichenlaub-Ritter
- Institute of Gene Technology/Microbiology, Faculty of Biology, University of Bielefeld, Bielefeld, Germany
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Homer HA. Modern management of recurrent miscarriage. Aust N Z J Obstet Gynaecol 2018; 59:36-44. [DOI: 10.1111/ajo.12920] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Accepted: 09/23/2018] [Indexed: 02/06/2023]
Affiliation(s)
- Hayden Anthony Homer
- Christopher Chen Oocyte Biology Research Laboratory, UQ Centre for Clinical Research; The University of Queensland; Brisbane Queensland Australia
- Reproductive Endocrinology & Infertility Clinic; Royal Brisbane & Women's Hospital; Brisbane Queensland Australia
- Queensland Fertility Group and Eve Health; Brisbane Queensland Australia
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70
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Eichenlaub-Ritter U. Weibliche Keimzellentwicklung. GYNAKOLOGISCHE ENDOKRINOLOGIE 2018. [DOI: 10.1007/s10304-018-0210-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Pontremoli C, Forni D, Cagliani R, Pozzoli U, Clerici M, Sironi M. Evolutionary rates of mammalian telomere-stability genes correlate with karyotype features and female germline expression. Nucleic Acids Res 2018; 46:7153-7168. [PMID: 29893967 PMCID: PMC6101625 DOI: 10.1093/nar/gky494] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Revised: 05/17/2018] [Accepted: 05/22/2018] [Indexed: 12/26/2022] Open
Abstract
Telomeres protect the ends of eukaryotic chromosomes and are essential for cell viability. In mammals, telomere dynamics vary with life history traits (e.g. body mass and longevity), suggesting differential selection depending on physiological characteristics. Telomeres, in analogy to centromeric regions, also represent candidate meiotic drivers and subtelomeric DNA evolves rapidly. We analyzed the evolutionary history of mammalian genes implicated in telomere homeostasis (TEL genes). We detected widespread positive selection and we tested two alternative hypotheses: (i) fast evolution is driven by changes in life history traits; (ii) a conflict with selfish DNA elements at the female meiosis represents the underlying selective pressure. By accounting for the phylogenetic relationships among mammalian species, we show that life history traits do not contribute to shape diversity of TEL genes. Conversely, the evolutionary rate of TEL genes correlates with expression levels during meiosis and episodes of positive selection across mammalian species are associated with karyotype features (number of chromosome arms). We thus propose a telomere drive hypothesis, whereby (sub)telomeres and telomere-binding proteins are engaged in an intra-genomic conflict similar to the one described for centromeres.
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Affiliation(s)
- Chiara Pontremoli
- Bioinformatics, Scientific Institute IRCCS E. MEDEA, 23842 Bosisio Parini, Italy
| | - Diego Forni
- Bioinformatics, Scientific Institute IRCCS E. MEDEA, 23842 Bosisio Parini, Italy
| | - Rachele Cagliani
- Bioinformatics, Scientific Institute IRCCS E. MEDEA, 23842 Bosisio Parini, Italy
| | - Uberto Pozzoli
- Bioinformatics, Scientific Institute IRCCS E. MEDEA, 23842 Bosisio Parini, Italy
| | - Mario Clerici
- Department of Physiopathology and Transplantation, University of Milan, 20090 Milan, Italy
- Don C. Gnocchi Foundation ONLUS, IRCCS, 20148 Milan, Italy
| | - Manuela Sironi
- Bioinformatics, Scientific Institute IRCCS E. MEDEA, 23842 Bosisio Parini, Italy
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Animal Female Meiosis: The Challenges of Eliminating Centrosomes. Cells 2018; 7:cells7070073. [PMID: 29996518 PMCID: PMC6071224 DOI: 10.3390/cells7070073] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Revised: 07/03/2018] [Accepted: 07/03/2018] [Indexed: 01/02/2023] Open
Abstract
Sexual reproduction requires the generation of gametes, which are highly specialised for fertilisation. Female reproductive cells, oocytes, grow up to large sizes when they accumulate energy stocks and store proteins as well as mRNAs to enable rapid cell divisions after fertilisation. At the same time, metazoan oocytes eliminate their centrosomes, i.e., major microtubule-organizing centres (MTOCs), during or right after the long growth phases. Centrosome elimination poses two key questions: first, how can the centrosome be re-established after fertilisation? In general, metazoan oocytes exploit sperm components, i.e., the basal body of the sperm flagellum, as a platform to reinitiate centrosome production. Second, how do most metazoan oocytes manage to build up meiotic spindles without centrosomes? Oocytes have evolved mechanisms to assemble bipolar spindles solely around their chromosomes without the guidance of pre-formed MTOCs. Female animal meiosis involves microtubule nucleation and organisation into bipolar microtubule arrays in regulated self-assembly under the control of the Ran system and nuclear transport receptors. This review summarises our current understanding of the molecular mechanism underlying self-assembly of meiotic spindles, its spatio-temporal regulation, and the key players governing this process in animal oocytes.
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