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Junyent S, Meglicki M, Vetter R, Mandelbaum R, King C, Patel EM, Iwamoto-Stohl L, Reynell C, Chen DY, Rubino P, Arrach N, Paulson RJ, Iber D, Zernicka-Goetz M. The first two blastomeres contribute unequally to the human embryo. Cell 2024; 187:2838-2854.e17. [PMID: 38744282 DOI: 10.1016/j.cell.2024.04.029] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Revised: 12/06/2023] [Accepted: 04/22/2024] [Indexed: 05/16/2024]
Abstract
Retrospective lineage reconstruction of humans predicts that dramatic clonal imbalances in the body can be traced to the 2-cell stage embryo. However, whether and how such clonal asymmetries arise in the embryo is unclear. Here, we performed prospective lineage tracing of human embryos using live imaging, non-invasive cell labeling, and computational predictions to determine the contribution of each 2-cell stage blastomere to the epiblast (body), hypoblast (yolk sac), and trophectoderm (placenta). We show that the majority of epiblast cells originate from only one blastomere of the 2-cell stage embryo. We observe that only one to three cells become internalized at the 8-to-16-cell stage transition. Moreover, these internalized cells are more frequently derived from the first cell to divide at the 2-cell stage. We propose that cell division dynamics and a cell internalization bottleneck in the early embryo establish asymmetry in the clonal composition of the future human body.
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Affiliation(s)
- Sergi Junyent
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Maciej Meglicki
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge CB2 3EG, UK
| | - Roman Vetter
- Department of Biosystems Science and Engineering (D-BSSE), ETH Zürich, Basel 4058, Switzerland; Swiss Institute of Bioinformatics (SIB), Mattenstrasse 26, 4058 Basel, Switzerland
| | - Rachel Mandelbaum
- Division of Reproductive Endocrinology and Infertility, Department of Obstetrics and Gynecology, University of Southern California, Los Angeles, CA 90033, USA
| | - Catherine King
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge CB2 3EG, UK
| | - Ekta M Patel
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Lisa Iwamoto-Stohl
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge CB2 3EG, UK
| | - Clare Reynell
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Dong-Yuan Chen
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Patrizia Rubino
- Division of Reproductive Endocrinology and Infertility, Department of Obstetrics and Gynecology, University of Southern California, Los Angeles, CA 90033, USA
| | | | - Richard J Paulson
- Division of Reproductive Endocrinology and Infertility, Department of Obstetrics and Gynecology, University of Southern California, Los Angeles, CA 90033, USA
| | - Dagmar Iber
- Department of Biosystems Science and Engineering (D-BSSE), ETH Zürich, Basel 4058, Switzerland; Swiss Institute of Bioinformatics (SIB), Mattenstrasse 26, 4058 Basel, Switzerland
| | - Magdalena Zernicka-Goetz
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA; Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge CB2 3EG, UK.
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2
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Pfeffer PL. The first lineage determination in mammals. Dev Biol 2024; 513:12-30. [PMID: 38761966 DOI: 10.1016/j.ydbio.2024.05.011] [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: 12/18/2023] [Revised: 03/15/2024] [Accepted: 05/16/2024] [Indexed: 05/20/2024]
Abstract
This review describes in detail the morphological, cytoskeletal and gene expression events leading to the gene regulatory network bifurcation point of trophoblast and inner cell mass cells in a variety of mammalian preimplantation embryos. The interrelated processes of compaction and polarity establishment are discussed in terms of how they affect YAP/WWTR activity and the location and fate of cells. Comparisons between mouse, human, cattle, pig and rabbit embryos suggest a conserved role for YAP/WWTR signalling in trophoblast induction in eutherian animals though the mechanisms for, and timing of, YAP/WWTR activation differs among species. Downstream targets show further differences, with the trophoblast marker GATA3 being a direct target in all examined mammals, while CDX2-positive and SOX2-negative regulation varies.
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Affiliation(s)
- Peter L Pfeffer
- School of Biological Sciences, Victoria University of Wellington, Wellington, New Zealand.
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3
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Ya A, Deng C, Godek KM. Cell Competition Eliminates Aneuploid Human Pluripotent Stem Cells. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.08.593217. [PMID: 38766106 PMCID: PMC11100710 DOI: 10.1101/2024.05.08.593217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2024]
Abstract
Human pluripotent stem cells (hPSCs) maintain diploid populations for generations despite a persistently high rate of mitotic errors that cause aneuploidy, or chromosome imbalances. Consequently, to maintain genome stability, aneuploidy must inhibit hPSC proliferation, but the mechanisms are unknown. Here, we surprisingly find that homogeneous aneuploid populations of hPSCs proliferate unlike aneuploid non-transformed somatic cells. Instead, in mosaic populations, cell non-autonomous competition between neighboring diploid and aneuploid hPSCs eliminates less fit aneuploid cells. Aneuploid hPSCs with lower Myc or higher p53 levels relative to diploid neighbors are outcompeted but conversely gain a selective advantage when Myc and p53 relative abundance switches. Thus, although hPSCs frequently missegregate chromosomes and inherently tolerate aneuploidy, Myc- and p53-driven cell competition preserves their genome integrity. These findings have important implications for the use of hPSCs in regenerative medicine and for how diploid human embryos are established despite the prevalence of aneuploidy during early development.
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Affiliation(s)
- Amanda Ya
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, NH, USA
- Dartmouth Cancer Center, Geisel School of Medicine at Dartmouth, Lebanon, NH, USA
| | - Chenhui Deng
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, NH, USA
- Dartmouth Cancer Center, Geisel School of Medicine at Dartmouth, Lebanon, NH, USA
| | - Kristina M. Godek
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, NH, USA
- Dartmouth Cancer Center, Geisel School of Medicine at Dartmouth, Lebanon, NH, USA
- Lead contact
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4
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Ardestani G, Banti M, García-Pascual CM, Navarro-Sánchez L, Van Zyl E, Castellón JA, Simón C, Sakkas D, Rubio C. Culture time to optimize embryo cell-free DNA analysis for frozen-thawed blastocysts undergoing noninvasive preimplantation genetic testing for aneuploidy. Fertil Steril 2024:S0015-0282(24)00271-1. [PMID: 38718960 DOI: 10.1016/j.fertnstert.2024.04.037] [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: 01/17/2024] [Revised: 04/25/2024] [Accepted: 04/29/2024] [Indexed: 05/26/2024]
Abstract
OBJECTIVE To investigate the ideal time in culture to optimize embryo cell-free deoxyribonucleic acid (cfDNA) analysis in frozen-thawed blastocysts undergoing noninvasive preimplantation genetic testing for aneuploidy (PGT-A). Cell-free DNA is released into the spent blastocyst media (spent media) by the embryo. However, the optimal timing to determine maximal cfDNA in the case of frozen-thawed blastocysts undergoing noninvasive PGT-A remains to be elucidated. DESIGN In this prospective observational study, 135 spent media and corresponding whole blastocysts were collected from January 2021 through March 2022. SETTING Private fertility clinics. PATIENTS Day-5 frozen-thawed blastocysts were cultured for 8 hours (Day-5 Short) or 24 hours (Day-5 Long), whereas day-6 frozen-thawed blastocysts were cultured for 8 hours (Day-6 Short). The spent media and whole blastocysts were then collected for further analysis. Spent media and whole blastocysts were amplified using whole genome amplification and sequenced using next-generation sequencing. MAIN OUTCOME MEASURES Informativity and concordance rates between cfDNA in spent media and whole blastocyst DNA were compared according to the different times in culture. RESULTS When comparing time in culture, informativity rates for spent media were significantly higher for Day-5 Long and Day-6 Short (>91%) compared with the Day-5 Short group (<60%). A similar trend was observed for cases with and without a previous PGT-A. Regarding blastocyst expansion grade, informativity rates were lower on Day-5 Short compared with Day-5 Long and Day-6 Short, regardless of expansion degree. This decrease was significant for Gardner-grade expansion grades 3, 4, and 5-6. In addition, for a similar time in culture, the grade of expansion did not have an impact on the informativity rates. For concordance rates, no significant differences were observed among the 3 groups. In all cases, concordance rates were 90.5% for Day-5 Short, 93.6% for Day-5 Long, and 92.3% for Day-6 Short. No impact of the expansion grade was observed on concordance rates. CONCLUSION Noninvasive PGT-A in frozen-thawed blastocysts yields very high concordance rates with whole blastocysts, possibly limiting the need for invasive PGT-A and making it available for a wider range of patients.
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Affiliation(s)
- Goli Ardestani
- Boston IVF - IVIRMA Global Research Alliance, Waltham, Massachusetts.
| | - Maria Banti
- Orchid Reproductive and Andrology Services, Dubai Healthcare, City, Dubai, United Arab Emirates
| | | | | | - Estee Van Zyl
- Orchid Reproductive and Andrology Services, Dubai Healthcare, City, Dubai, United Arab Emirates
| | | | - Carlos Simón
- Department of Obstetrics and Gynecology, University of Valencia, Spain; BIDMC Harvard University, Boston, Massachusetts; Carlos Simon Foundation, INCLIVA, Valencia, Spain
| | - Denny Sakkas
- Boston IVF - IVIRMA Global Research Alliance, Waltham, Massachusetts
| | - Carmen Rubio
- R&D Department, Igenomix, Paterna, Valencia, Spain
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5
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Saraceno C, Timoshevskiy VA, Smith JJ. Functional analyses of the polycomb-group genes in sea lamprey embryos undergoing programmed DNA loss. JOURNAL OF EXPERIMENTAL ZOOLOGY. PART B, MOLECULAR AND DEVELOPMENTAL EVOLUTION 2024; 342:260-270. [PMID: 37902302 DOI: 10.1002/jez.b.23225] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Revised: 09/22/2023] [Accepted: 10/03/2023] [Indexed: 10/31/2023]
Abstract
During early development, sea lamprey embryos undergo programmatic elimination of DNA from somatic progenitor cells in a process termed programmed genome rearrangement (PGR). Eliminated DNA eventually becomes condensed into micronuclei, which are then physically degraded and permanently lost from the cell. Previous studies indicated that many of the genes eliminated during PGR have mammalian homologs that are bound by polycomb repressive complex (PRC) in embryonic stem cells. To test whether PRC components play a role in the faithful elimination of germline-specific sequences, we used a combination of CRISPR/Cas9 and lightsheet microscopy to investigate the impact of gene knockouts on early development and the progression through stages of DNA elimination. Analysis of knockout embryos for the core PRC2 subunits EZH, SUZ12, and EED show that disruption of all three genes results in an increase in micronucleus number, altered distribution of micronuclei within embryos, and an increase in micronucleus volume in mutant embryos. While the upstream events of DNA elimination are not strongly impacted by loss of PRC2 components, this study suggests that PRC2 plays a role in the later stages of elimination related to micronucleus condensation and degradation. These findings also suggest that other genes/epigenetic pathways may work in parallel during DNA elimination to mediate chromatin structure, accessibility, and the ultimate loss of germline-specific DNA.
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Affiliation(s)
- Cody Saraceno
- Department of Biology, University of Kentucky, Lexington, Kentucky, USA
| | | | - Jeramiah J Smith
- Department of Biology, University of Kentucky, Lexington, Kentucky, USA
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6
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Zhang X, Zheng PS. Mechanism of chromosomal mosaicism in preimplantation embryos and its effect on embryo development. J Assist Reprod Genet 2024; 41:1127-1141. [PMID: 38386118 PMCID: PMC11143108 DOI: 10.1007/s10815-024-03048-2] [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: 09/11/2023] [Accepted: 01/30/2024] [Indexed: 02/23/2024] Open
Abstract
Aneuploidy is one of the main causes of miscarriage and in vitro fertilization failure. Mitotic abnormalities in preimplantation embryos are the main cause of mosaicism, which may be influenced by several endogenous factors such as relaxation of cell cycle control mechanisms, defects in chromosome cohesion, centrosome aberrations and abnormal spindle assembly, and DNA replication stress. In addition, incomplete trisomy rescue is a rare cause of mosaicism. However, there may be a self-correcting mechanism in mosaic embryos, which allows some mosaicisms to potentially develop into normal embryos. At present, it is difficult to accurately diagnose mosaicism using preimplantation genetic testing for aneuploidy. Therefore, in clinical practice, embryos diagnosed as mosaic should be considered comprehensively based on the specific situation of the patient.
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Affiliation(s)
- Xue Zhang
- Department of Reproductive Medicine, The First Affiliated Hospital, Xi'an Jiaotong University of Medical School, Xi'an, 710061, Shanxi, P.R. China
| | - Peng-Sheng Zheng
- Department of Reproductive Medicine, The First Affiliated Hospital, Xi'an Jiaotong University of Medical School, Xi'an, 710061, Shanxi, P.R. China.
- Section of Cancer Stem Cell Research, Key Laboratory of Environment and Genes Related to Diseases, Ministry of Education of People's Republic of China, Xi'an, 710061, Shanxi, P.R. China.
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7
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Rossant J. Why study human embryo development? Dev Biol 2024; 509:43-50. [PMID: 38325560 DOI: 10.1016/j.ydbio.2024.02.001] [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: 08/21/2023] [Revised: 12/31/2023] [Accepted: 02/01/2024] [Indexed: 02/09/2024]
Abstract
Understanding the processes and mechanisms underlying early human embryo development has become an increasingly active and important area of research. It has potential for insights into important clinical issues such as early pregnancy loss, origins of congenital anomalies and developmental origins of adult disease, as well as fundamental insights into human biology. Improved culture systems for preimplantation embryos, combined with the new tools of single cell genomics and live imaging, are providing new insights into the similarities and differences between human and mouse development. However, access to human embryo material is still restricted and extended culture of early embryos has regulatory and ethical concerns. Stem cell-derived models of different phases of human development can potentially overcome these limitations and provide a scalable source of material to explore the early postimplantation stages of human development. To date, such models are clearly incomplete replicas of normal development but future technological improvements can be envisaged. The ethical and regulatory environment for such studies remains to be fully resolved.
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Affiliation(s)
- Janet Rossant
- The Gairdner Foundation and the Hospital for Sick Children, University of Toronto, MaRS Centre, Heritage Building, 101 College Street, Suite 335, Toronto, Ontario, M5G 1L7, Canada.
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8
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Budrewicz J, Chavez SL. Insights into embryonic chromosomal instability: mechanisms of DNA elimination during mammalian preimplantation development. Front Cell Dev Biol 2024; 12:1344092. [PMID: 38374891 PMCID: PMC10875028 DOI: 10.3389/fcell.2024.1344092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2023] [Accepted: 01/15/2024] [Indexed: 02/21/2024] Open
Abstract
Mammalian preimplantation embryos often contend with aneuploidy that arose either by the inheritance of meiotic errors from the gametes, or from mitotic mis-segregation events that occurred following fertilization. Regardless of the origin, mis-segregated chromosomes become encapsulated in micronuclei (MN) that are spatially isolated from the main nucleus. Much of our knowledge of MN formation comes from dividing somatic cells during tumorigenesis, but the error-prone cleavage-stage of early embryogenesis is fundamentally different. One unique aspect is that cellular fragmentation (CF), whereby small subcellular bodies pinch off embryonic blastomeres, is frequently observed. CF has been detected in both in vitro and in vivo-derived embryos and likely represents a response to chromosome mis-segregation since it only appears after MN formation. There are multiple fates for MN, including sequestration into CFs, but the molecular mechanism(s) by which this occurs remains unclear. Due to nuclear envelope rupture, the chromosomal material contained within MN and CFs becomes susceptible to double stranded-DNA breaks. Despite this damage, embryos may still progress to the blastocyst stage and exclude chromosome-containing CFs, as well as non-dividing aneuploid blastomeres, from participating in further development. Whether these are attempts to rectify MN formation or eliminate embryos with poor implantation potential is unknown and this review will discuss the potential implications of DNA removal by CF/blastomere exclusion. We will also extrapolate what is known about the intracellular pathways mediating MN formation and rupture in somatic cells to preimplantation embryogenesis and how nuclear budding and DNA release into the cytoplasm may impact overall development.
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Affiliation(s)
- Jacqueline Budrewicz
- Department of Molecular and Medical Genetics, Oregon Health and Science University, Portland, OR, United States
- Division of Reproductive and Developmental Sciences, Oregon National Primate Research Center, Beaverton, OR, United States
| | - Shawn L. Chavez
- Department of Molecular and Medical Genetics, Oregon Health and Science University, Portland, OR, United States
- Division of Reproductive and Developmental Sciences, Oregon National Primate Research Center, Beaverton, OR, United States
- Department of Obstetrics and Gynecology, Oregon Health and Science University, Portland, OR, United States
- Department of Biomedical Engineering, Oregon Health and Science University, Portland, OR, United States
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9
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Phillips TA, Marcotti S, Cox S, Parsons M. Imaging actin organisation and dynamics in 3D. J Cell Sci 2024; 137:jcs261389. [PMID: 38236161 PMCID: PMC10906668 DOI: 10.1242/jcs.261389] [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] [Indexed: 01/19/2024] Open
Abstract
The actin cytoskeleton plays a critical role in cell architecture and the control of fundamental processes including cell division, migration and survival. The dynamics and organisation of F-actin have been widely studied in a breadth of cell types on classical two-dimensional (2D) surfaces. Recent advances in optical microscopy have enabled interrogation of these cytoskeletal networks in cells within three-dimensional (3D) scaffolds, tissues and in vivo. Emerging studies indicate that the dimensionality experienced by cells has a profound impact on the structure and function of the cytoskeleton, with cells in 3D environments exhibiting cytoskeletal arrangements that differ to cells in 2D environments. However, the addition of a third (and fourth, with time) dimension leads to challenges in sample preparation, imaging and analysis, necessitating additional considerations to achieve the required signal-to-noise ratio and spatial and temporal resolution. Here, we summarise the current tools for imaging actin in a 3D context and highlight examples of the importance of this in understanding cytoskeletal biology and the challenges and opportunities in this domain.
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Affiliation(s)
- Thomas A. Phillips
- Randall Centre for Cell and Molecular Biophysics, King's College London, New Hunts House, Guys Campus, London SE1 1UL, UK
| | - Stefania Marcotti
- Randall Centre for Cell and Molecular Biophysics, King's College London, New Hunts House, Guys Campus, London SE1 1UL, UK
- Microscopy Innovation Centre, King's College London, Guys Campus, London SE1 1UL, UK
| | - Susan Cox
- Randall Centre for Cell and Molecular Biophysics, King's College London, New Hunts House, Guys Campus, London SE1 1UL, UK
| | - Maddy Parsons
- Randall Centre for Cell and Molecular Biophysics, King's College London, New Hunts House, Guys Campus, London SE1 1UL, UK
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Rhon-Calderon EA, Hemphill CN, Vrooman LA, Rosier CL, Lan Y, Ord T, Coutifaris C, Mainigi M, Schultz RM, Bartolomei MS. Trophectoderm biopsy of blastocysts following IVF and embryo culture increases epigenetic dysregulation in a mouse model. Hum Reprod 2024; 39:154-176. [PMID: 37994669 PMCID: PMC11032714 DOI: 10.1093/humrep/dead238] [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: 03/05/2023] [Revised: 10/29/2023] [Indexed: 11/24/2023] Open
Abstract
STUDY QUESTION Does trophectoderm biopsy (TEBx) of blastocysts for preimplantation genetic testing in the clinic affect normal placental and embryo development and offspring metabolic outcomes in a mouse model? SUMMARY ANSWER TEBx impacts placental and embryonic health during early development, with some alterations resolving and others worsening later in development and triggering metabolic changes in adult offspring. WHAT IS KNOWN ALREADY Previous studies have not assessed the epigenetic and morphological impacts of TEBx either in human populations or in animal models. STUDY DESIGN, SIZE, DURATION We employed a mouse model to identify the effects of TEBx during IVF. Three groups were assessed: naturally conceived (Naturals), IVF, and IVF + TEBx, at two developmental timepoints: embryonic day (E)12.5 (n = 40/Naturals, n = 36/IVF, and n = 36/IVF + TEBx) and E18.5 (n = 42/Naturals, n = 30/IVF, and n = 35/IVF + TEBx). Additionally, to mimic clinical practice, we assessed a fourth group: IVF + TEBx + Vitrification (Vit) at E12.5 (n = 29) that combines TEBx and vitrification. To assess the effect of TEBx in offspring health, we characterized a 12-week-old cohort (n = 24/Naturals, n = 25/IVF and n = 25/IVF + TEBx). PARTICIPANTS/MATERIALS, SETTING, METHODS Our mouse model used CF-1 females as egg donors and SJL/B6 males as sperm donors. IVF, TEBx, and vitrification were performed using standardized methods. Placenta morphology was evaluated by hematoxylin-eosin staining, in situ hybridization using Tpbpa as a junctional zone marker and immunohistochemistry using CD34 fetal endothelial cell markers. For molecular analysis of placentas and embryos, DNA methylation was analyzed using pyrosequencing, luminometric methylation assay, and chip array technology. Expression patterns were ascertained by RNA sequencing. Triglycerides, total cholesterol, high-, low-, and very low-density lipoprotein, insulin, and glucose were determined in the 12-week-old cohort using commercially available kits. MAIN RESULTS AND THE ROLE OF CHANCE We observed that at E12.5, IVF + TEBx had a worse outcome in terms of changes in DNA methylation and differential gene expression in placentas and whole embryos compared with IVF alone and compared with Naturals. These changes were reflected in alterations in placental morphology and blood vessel density. At E18.5, early molecular changes in fetuses were maintained or exacerbated. With respect to placentas, the molecular and morphological changes, although different compared to Naturals, were equivalent to the IVF group, except for changes in blood vessel density, which persisted. Of note is that most differences were sex specific. We conclude that TEBx has more detrimental effects in mid-gestation placental and embryonic tissues, with alterations in embryonic tissues persisting or worsening in later developmental stages compared to IVF alone, and the addition of vitrification after TEBx results in more pronounced and potentially detrimental epigenetic effects: these changes are significantly different compared to Naturals. Finally, we observed that 12-week IVF + TEBx offspring, regardless of sex, showed higher glucose, insulin, triglycerides, lower total cholesterol, and lower high-density lipoprotein compared to IVF and Naturals, with only males having higher body weight compared to IVF and Naturals. Our findings in a mouse model additionally support the need for more studies to assess the impact of new procedures in ART to ensure healthy pregnancies and offspring outcomes. LARGE SCALE DATA Data reported in this work have been deposited in the NCBI Gene Expression Omnibus under accession number GSE225318. LIMITATIONS, REASONS FOR CAUTION This study was performed using a mouse model that mimics many clinical IVF procedures and outcomes observed in humans, where studies on early embryos are not possible. WIDER IMPLICATIONS OF THE FINDINGS This study highlights the importance of assaying new procedures used in ART to assess their impact on placenta and embryo development, and offspring metabolic outcomes. STUDY FUNDING/COMPETING INTEREST(S) This work was funded by a National Centers for Translational Research in Reproduction and Infertility grant P50 HD068157-06A1 (M.S.B., C.C., M.M.), Ruth L. Kirschstein National Service Award Individual Postdoctoral Fellowship F32 HD107914 (E.A.R.-C.) and F32 HD089623 (L.A.V.), and National Institutes of Health Training program in Cell and Molecular Biology T32 GM007229 (C.N.H.). No conflict of interest.
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Affiliation(s)
- Eric A Rhon-Calderon
- Department of Cell and Developmental Biology, Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Cassidy N Hemphill
- Department of Cell and Developmental Biology, Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Lisa A Vrooman
- Department of Cell and Developmental Biology, Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Casey L Rosier
- Department of Cell and Developmental Biology, Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Yemin Lan
- Department of Cell and Developmental Biology, Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Teri Ord
- Center for Research on Reproduction and Women’s Health, University of Pennsylvania, Philadelphia, PA, USA
| | - Christos Coutifaris
- Center for Research on Reproduction and Women’s Health, University of Pennsylvania, Philadelphia, PA, USA
- Division of Reproductive Endocrinology and Infertility, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Monica Mainigi
- Center for Research on Reproduction and Women’s Health, University of Pennsylvania, Philadelphia, PA, USA
- Division of Reproductive Endocrinology and Infertility, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Richard M Schultz
- Department of Biology, School of Arts and Sciences, University of Pennsylvania, Philadelphia, PA, USA
- Department of Anatomy, Physiology, and Cell Biology, School of Veterinary Medicine, UC Davis, Davis, CA, USA
| | - Marisa S Bartolomei
- Department of Cell and Developmental Biology, Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Center for Research on Reproduction and Women’s Health, University of Pennsylvania, Philadelphia, PA, USA
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11
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Chavli EA, Klaasen SJ, Van Opstal D, Laven JS, Kops GJ, Baart EB. Single-cell DNA sequencing reveals a high incidence of chromosomal abnormalities in human blastocysts. J Clin Invest 2024; 134:e174483. [PMID: 38175717 PMCID: PMC10940095 DOI: 10.1172/jci174483] [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: 08/04/2023] [Accepted: 01/02/2024] [Indexed: 01/05/2024] Open
Abstract
Aneuploidy, a deviation from the normal chromosome copy number, is common in human embryos and is considered a primary cause of implantation failure and early pregnancy loss. Meiotic errors lead to uniformly abnormal karyotypes, while mitotic errors lead to chromosomal mosaicism: the presence of cells with at least 2 different karyotypes within an embryo. Knowledge about mosaicism in blastocysts mainly derives from bulk DNA sequencing (DNA-Seq) of multicellular trophectoderm (TE) and/or inner cell mass (ICM) samples. However, this can only detect an average net gain or loss of DNA above a detection threshold of 20%-30%. To accurately assess mosaicism, we separated the TE and ICM of 55 good-quality surplus blastocysts and successfully applied single-cell whole-genome sequencing (scKaryo-Seq) on 1,057 cells. Mosaicism involving numerical and structural chromosome abnormalities was detected in 82% of the embryos, in which most abnormalities affected less than 20% of the cells. Structural abnormalities, potentially caused by replication stress and DNA damage, were observed in 69% of the embryos. In conclusion, our findings indicated that mosaicism was prevalent in good-quality blastocysts, whereas these blastocysts would likely be identified as normal with current bulk DNA-Seq techniques used for preimplantation genetic testing for aneuploidy.
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Affiliation(s)
- Effrosyni A. Chavli
- Division of Reproductive Endocrinology and Infertility, Department of Obstetrics and Gynecology, Erasmus MC, University Medical Center Rotterdam, Rotterdam, Netherlands
| | - Sjoerd J. Klaasen
- Hubrecht Institute-KNAW (Royal Academy of Arts and Sciences) and University Medical Center Utrecht, Utrecht, Netherlands
- Oncode Institute, Utrecht, Netherlands
| | | | - Joop S.E. Laven
- Division of Reproductive Endocrinology and Infertility, Department of Obstetrics and Gynecology, Erasmus MC, University Medical Center Rotterdam, Rotterdam, Netherlands
| | - Geert J.P.L. Kops
- Hubrecht Institute-KNAW (Royal Academy of Arts and Sciences) and University Medical Center Utrecht, Utrecht, Netherlands
- Oncode Institute, Utrecht, Netherlands
| | - Esther B. Baart
- Division of Reproductive Endocrinology and Infertility, Department of Obstetrics and Gynecology, Erasmus MC, University Medical Center Rotterdam, Rotterdam, Netherlands
- Department of Developmental Biology, Erasmus MC, University Medical Center Rotterdam, Rotterdam, Netherlands
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12
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Chung C, Yang X, Gleeson JG. Post-zygotic brain mosaicism as a result of partial reversion of pre-zygotic aneuploidy. Nat Genet 2023; 55:1784-1785. [PMID: 37872451 PMCID: PMC10842191 DOI: 10.1038/s41588-023-01552-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2023]
Affiliation(s)
- Changuk Chung
- Rady Children's Institute of Genomic Medicine, Department of Neurosciences, University of California, San Diego, La Jolla, CA, USA
| | - Xiaoxu Yang
- Rady Children's Institute of Genomic Medicine, Department of Neurosciences, University of California, San Diego, La Jolla, CA, USA
| | - Joseph G Gleeson
- Rady Children's Institute of Genomic Medicine, Department of Neurosciences, University of California, San Diego, La Jolla, CA, USA.
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13
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Al Jord A, Verlhac MH. Dyes illuminate live human embryogenesis. Cell 2023; 186:3143-3145. [PMID: 37478818 DOI: 10.1016/j.cell.2023.06.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Revised: 06/15/2023] [Accepted: 06/15/2023] [Indexed: 07/23/2023]
Abstract
Assisted reproduction is on the rise globally. Cell morphology is commonly used for embryo selection, but the cell biology of early preimplantation development remains poorly understood. In this issue of Cell, Domingo-Muelas et al. reveal novel features of human embryos with critical implications for preimplantation genetic testing.
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Affiliation(s)
- Adel Al Jord
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS, INSERM, Université PSL, Paris, France.
| | - Marie-Hélène Verlhac
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS, INSERM, Université PSL, Paris, France.
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14
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Okabe M, Shirasawa H, Ono Y, Goto M, Iwasawa T, Sakaguchi T, Fujishima A, Onodera Y, Makino K, Miura H, Kumazawa Y, Takahashi K, Terada Y. An approach for live imaging of first cleavage in mouse embryos using fluorescent chemical probes for DNA, microtubules, and microfilaments. Reprod Med Biol 2023; 22:e12551. [PMID: 38023339 PMCID: PMC10680128 DOI: 10.1002/rmb2.12551] [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: 08/09/2023] [Revised: 10/27/2023] [Accepted: 11/10/2023] [Indexed: 12/01/2023] Open
Abstract
Purpose Dynamic morphological changes in the chromosome and cytoskeleton occur in mammals and humans during early embryonic development, and abnormalities such as embryonic chromosomal aneuploidy occur when development does not proceed normally. Visualization of the intracellular organelles and cytoskeleton allows elucidation of the development of early mammalian embryos. The behavior of the DNA and cytoskeleton in early mammalian embryos has conventionally been observed by injecting target molecule mRNAs, incorporating a fluorescent substance-expressing gene, into embryos. In this study, we visualized the chronological behavior of male and female chromosome condensation in mouse embryos, beginning in the two-pronuclear zygote, through the first division to the two-cell stage, using fluorescent chemical probes to visualize the behavior of DNA, microtubules, and microfilaments. Method Mouse two-pronuclear stage embryo were immersed in medium containing fluorescent chemical probes to visualize DNA, microtubules, and microfilaments. Observation was performed with a confocal microscope. Results This method allowed us to observe how chromosome segregation errors in first somatic cell divisions in mouse embryos and enabled dynamic analysis of a phenomenon called lagging chromosomes. Conclusions By applying this method, we can observe any stage of embryonic development, which may provide new insights into embryonic development in other mammals.
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Affiliation(s)
- Motonari Okabe
- Department of Obstetrics and GynecologyAkita University Graduate School of MedicineAkitaJapan
| | - Hiromitsu Shirasawa
- Department of Obstetrics and GynecologyAkita University Graduate School of MedicineAkitaJapan
| | - Yuki Ono
- Department of Obstetrics and GynecologyAkita University Graduate School of MedicineAkitaJapan
| | - Mayumi Goto
- Department of Obstetrics and GynecologyAkita University Graduate School of MedicineAkitaJapan
| | - Takuya Iwasawa
- Department of Obstetrics and GynecologyAkita University Graduate School of MedicineAkitaJapan
| | - Taichi Sakaguchi
- Department of Obstetrics and GynecologyAkita University Graduate School of MedicineAkitaJapan
| | - Akiko Fujishima
- Department of Obstetrics and GynecologyAkita University Graduate School of MedicineAkitaJapan
| | - Yohei Onodera
- Department of Obstetrics and GynecologyAkita University Graduate School of MedicineAkitaJapan
| | - Kenichi Makino
- Department of Obstetrics and GynecologyAkita University Graduate School of MedicineAkitaJapan
| | - Hiroshi Miura
- Department of Obstetrics and GynecologyAkita University Graduate School of MedicineAkitaJapan
| | - Yukiyo Kumazawa
- Department of Obstetrics and GynecologyAkita University Graduate School of MedicineAkitaJapan
| | - Kazumasa Takahashi
- Department of Obstetrics and GynecologyAkita University Graduate School of MedicineAkitaJapan
| | - Yukihiro Terada
- Department of Obstetrics and GynecologyAkita University Graduate School of MedicineAkitaJapan
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