Functional analyses of the polycomb‐group genes in sea lamprey embryos undergoing programmed DNA loss DOI Creative Commons

Cody Saraceno,

Vladimir A. Timoshevskiy, Jeramiah J. Smith

et al.

Journal of Experimental Zoology Part B Molecular and Developmental Evolution, Journal Year: 2023, Volume and Issue: 342(3), P. 260 - 270

Published: Oct. 30, 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 eventually becomes condensed into micronuclei, which are then physically degraded and permanently lost the cell. Previous studies indicated that many genes eliminated during PGR have mammalian homologs bound by polycomb repressive complex (PRC) embryonic stem cells. To test whether PRC components play role faithful germline‐specific sequences, we used combination CRISPR/Cas9 lightsheet microscopy to investigate impact gene knockouts on development progression through stages elimination. Analysis knockout for core PRC2 subunits EZH, SUZ12, EED show disruption all three results an increase micronucleus number, altered distribution micronuclei within embryos, volume mutant embryos. While upstream events not strongly impacted loss components, this study suggests plays later related condensation degradation. These findings also suggest other genes/epigenetic pathways may work parallel mediate chromatin structure, accessibility, ultimate DNA.

Language: Английский

Cytoplasmic strings in human blastocysts: hypotheses of their role and implications for embryo selection DOI

Anabella Marconetto,

Federica Innocenti,

G Saturno

et al.

Human Reproduction, Journal Year: 2024, Volume and Issue: 39(11), P. 2453 - 2465

Published: Oct. 2, 2024

Abstract STUDY QUESTION What are the implications of presence cytoplasmic strings (Cyt-S) and their quantity dynamics for pre-implantation development human blastocysts? SUMMARY ANSWER Cyt-S common in embryos associated with faster blastocyst development, larger expansion, better morphological quality. WHAT IS KNOWN ALREADY dynamic cellular projections connecting inner cell mass trophectoderm (TE) cells, that can be observed during expansion. Their prevalence has been estimated to between 44% 93%. Data relevant clinical role lacking, limited, or controversial. DESIGN, SIZE, DURATION Retrospective study conducted at a single IVF center May 2013 November 2014 involving 124 genetic testing aneuploidy cycles time-lapse incubator ≥1 biopsied vitrified (N = 370 assessed). These resulted 87 vitrified-warmed single-euploid transfers. PARTICIPANTS/MATERIALS, SETTING, METHODS ICSI, continuous culture (Days 5–7), TE biopsy fully expanded blastocysts without Day 3 zona pellucida drilling, qPCR assess uniform full-chromosome aneuploidies, vitrification were all performed. Only euploid single-embryo-transfers conducted. Blastocyst quality was defined according Gardner’s criteria. The AI-based software CHLOE™ (Fairtility) automatically registered timings from time starting blastulation (tSB) (t-biopsy, i.e. full-expansion) as hours-post-insemination (hpi), embryo area (including µm2), spontaneous collapses. One senior embryologist manually annotated presence, quantity, timings, type (thick cell-to-cell connections and/or threads). All significant associations confirmed through regression analyses. couples’, cycles’, embryos’ main features also tested dynamics. MAIN RESULTS AND THE ROLE OF CHANCE About 94.3% patients 117/124) had Cyt-S. Out total blastocysts, 55 degenerated full-expansion 55/370, 14.9%). degeneration rate among 10.8% 33/304), significantly lower than (33.3%, N 22/66, P < 0.01). Of remaining 315 viable analyzed, 86% 271/315; 0.01) Cyt-S, on average 3.5 ± 2.1 per ranging 1–13. first appeared 115.3 12.5 hpi (85.7–157.7), corresponding 10.5 5.8 h (0.5–31) after tSB. Overall, we analyzed 937 showing mean duration 3.8 2.7 (0.3–20.9). mostly threads 508/937, 54.2%) thick becoming 382/937, 40.8%) bridges 47/937, 5.0%). developmentally (on 6–12 faster) more 2700 µm2-larger blastocyst’s t-biopsy) embryos. Also, morphology. Lastly, while euploidy rates comparable transferred latter group failed implant 10). LIMITATIONS, REASONS FOR CAUTION assessed seven focal planes video frames recorded every 15 min. included advanced maternal age. could reported, but no causations/consequences. datasets required outcomes. WIDER IMPLICATIONS FINDINGS suggesting physiological implication this process. mirror viability, quality, yet is still unknown. Future basic science studies encouraged finally describe molecular nature biophysical properties, Artificial Intelligence tools should aid these by incorporating assessment. FUNDING/COMPETING INTEREST(S) None. TRIAL REGISTRATION NUMBER N/A.

Language: Английский

Citations

1
Complex aneuploidy triggers autophagy and p53-mediated apoptosis and impairs the second lineage segregation in human preimplantation embryos DOI Creative Commons
Marius Regin,

Yingnan Lei,

Edouard Couvreu de Deckersberg

et al.

eLife, Journal Year: 2024, Volume and Issue: 12

Published: Dec. 9, 2024

About 70% of human cleavage stage embryos show chromosomal mosaicism, falling to 20% in blastocysts. Chromosomally mosaic blastocysts can implant and lead healthy new-borns with normal karyotypes. Studies mouse gastruloids showed that aneuploid cells are eliminated from the epiblast by p53-mediated apoptosis while being tolerated trophectoderm. These observations suggest a selective loss embryos, but underlying mechanisms not yet fully understood. Here, we investigated cellular consequences aneuploidy total 125 RNA-sequencing trophectoderm activated p53 pathway proportionate level imbalance. Immunostaining corroborated triggers proteotoxic stress, autophagy, p53-signaling, independent DNA damage. Total cell numbers were lower due decline both epiblast/primitive endoderm numbers. While may be attributed apoptosis, impaired second lineage segregation, particularly primitive formation. This might reinforced retention NANOG. Our findings explain why fail further develop hypothesize same removal embryos.

Language: Английский

Citations

1
Complex aneuploidy triggers autophagy and p53-mediated apoptosis and impairs the second lineage segregation in human preimplantation embryos DOI Creative Commons
Marius Regin,

Yingnan Lei,

Edouard Couvreu de Deckersberg

et al.

eLife, Journal Year: 2023, Volume and Issue: 12

Published: Sept. 8, 2023

About 70% of human cleavage stage embryos show chromosomal mosaicism, falling to 20% in blastocysts. Chromosomally mosaic blastocysts can implant and lead healthy new-borns with normal karyotypes. Studies mouse gastruloids showed that aneuploid cells are eliminated from the epiblast by p53-mediated apoptosis while being tolerated trophectoderm. These observations suggest a selective loss embryos, but underlying mechanisms not yet fully understood. Here, we investigated cellular consequences aneuploidy total 125 RNA-sequencing trophectoderm activated p53 pathway proportionate level imbalance. Immunostaining corroborated triggers proteotoxic stress, autophagy, p53-signaling, independent DNA damage. Total cell numbers were lower due decline both epiblast/primitive endoderm numbers. While may be attributed apoptosis, impaired second lineage segregation, particularly primitive formation. This might reinforced retention NANOG. Our findings explain why fail further develop hypothesize same removal embryos.

Language: Английский

Citations

3
Post-zygotic brain mosaicism as a result of partial reversion of pre-zygotic aneuploidy DOI
Changuk Chung, Xiaoxu Yang,

Joseph G. Gleeson

et al.

Nature Genetics, Journal Year: 2023, Volume and Issue: 55(11), P. 1784 - 1785

Published: Oct. 23, 2023

Language: Английский

Citations

3
Functional analyses of the polycomb‐group genes in sea lamprey embryos undergoing programmed DNA loss DOI Creative Commons

Cody Saraceno,

Vladimir A. Timoshevskiy, Jeramiah J. Smith

et al.

Journal of Experimental Zoology Part B Molecular and Developmental Evolution, Journal Year: 2023, Volume and Issue: 342(3), P. 260 - 270

Published: Oct. 30, 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 eventually becomes condensed into micronuclei, which are then physically degraded and permanently lost the cell. Previous studies indicated that many genes eliminated during PGR have mammalian homologs bound by polycomb repressive complex (PRC) embryonic stem cells. To test whether PRC components play role faithful germline‐specific sequences, we used combination CRISPR/Cas9 lightsheet microscopy to investigate impact gene knockouts on development progression through stages elimination. Analysis knockout for core PRC2 subunits EZH, SUZ12, EED show disruption all three results an increase micronucleus number, altered distribution micronuclei within embryos, volume mutant embryos. While upstream events not strongly impacted loss components, this study suggests plays later related condensation degradation. These findings also suggest other genes/epigenetic pathways may work parallel mediate chromatin structure, accessibility, ultimate DNA.

Language: Английский

Citations

2