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Project description:BackgroundPigs are important animals for agricultural and biomedical research, and improvement is needed for use of the assisted reproductive technologies. Determining underlying mechanisms of epigenetic reprogramming in the early stage of preimplantation embryos derived from in vitro fertilization (IVF), parthenogenesis, and androgenesis will not only contribute to assisted reproductive technologies of pigs but also will shed light into early human development. However, the reprogramming of three-dimensional architecture of chromatin in this process in pigs is poorly understood.ResultsWe generate three-dimensional chromatin profiles for pig somatic cells, IVF, parthenogenesis, and androgenesis preimplantation embryos. We find that the chromosomes in the pig preimplantation embryos are enriched for superdomains, which are more rare in mice. However, p(s) curves, compartments, and topologically associated domains (TADs) are largely conserved in somatic cells and are gradually established during preimplantation embryogenesis in both mammals. In the uniparental pig embryos, the establishment of chromatin architecture is highly asynchronized at all levels from IVF embryos, and a remarkably strong decompartmentalization is observed during zygotic genome activation (ZGA). Finally, chromosomes originating from oocytes always establish TADs faster than chromosomes originating from sperm, both before and during ZGA.ConclusionsOur data highlight a potential unique 3D chromatin pattern of enriched superdomains in pig preimplantation embryos, an unusual decompartmentalization process during ZGA in the uniparental embryos, and an asynchronized TAD reprogramming between maternal and paternal genomes, implying a severe dysregulation of ZGA in the uniparental embryos in pigs.
| S-EPMC7418210 | biostudies-literature
Project description:Pigs are important animals for agricultural and biomedical research, and its assisted reproductive technologies are urgently needed to be improved. Determining the underlying mechanism of epigenetic reprogramming in the early stage of preimplantation embryos derived from in vitro fertilization (IVF), parthenogenesis (PA) and androgenesis (AG), will not only contribute to assisted reproduction technologies of pigs but also will shed light into early human development. We generated 3D chromatin profiles for pig somatic cells, IVF, PA and AG preimplantation embryos. We found that the chromosomes in the pig preimplantation embryos are enriched for superdomains, i.e., the larger than 10M compartment domains, which are much rarer in mice. Wheras, p(s) curves, compartments and TADs, are largely conserved in somatic cells, and are gradually establishing during preimplantation embryogenesis. In the uniparental pig embryos, the establishment of chromatin architecture was highly asynchronized at all levels from IVF embryos, and a remarkably strong decompartmentalization was observed during zygotic genome activation (ZGA). Finally, chromosomes originating from oocytes always establish TADs faster than chromosomes originating from sperm, both before and during ZGA.
2020-07-02 | GSE153451 | GEO
Project description:Pigs are important animals for agricultural and biomedical research, and its assisted reproductive technologies are urgently needed to be improved. Determining the underlying mechanism of epigenetic reprogramming in the early stage of preimplantation embryos derived from in vitro fertilization (IVF), parthenogenesis (PA) and androgenesis (AG), will not only contribute to assisted reproduction technologies of pigs but also will shed light into early human development. We generated 3D chromatin profiles for pig somatic cells, IVF, PA and AG preimplantation embryos. We found that the chromosomes in the pig preimplantation embryos are enriched for superdomains, i.e., the larger than 10M compartment domains, which are much rarer in mice. Wheras, p(s) curves, compartments and TADs, are largely conserved in somatic cells, and are gradually establishing during preimplantation embryogenesis. In the uniparental pig embryos, the establishment of chromatin architecture was highly asynchronized at all levels from IVF embryos, and a remarkably strong decompartmentalization was observed during zygotic genome activation (ZGA). Finally, chromosomes originating from oocytes always establish TADs faster than chromosomes originating from sperm, both before and during ZGA.
2020-07-02 | GSE153450 | GEO
Project description:The asynchronous establishment of chromatin 3D architecture between in vitro fertilized and uniparental preimplantation pig embryos
| PRJNA642737 | ENA
Project description:The asynchronous establishment of chromatin 3D architecture between in vitro fertilized and uniparental preimplantation pig embryos [Hi-C]
| PRJNA642743 | ENA
Project description:The asynchronous establishment of chromatin 3D architecture between in vitro fertilized and uniparental preimplantation pig embryos [ChIP-seq]
| PRJNA642744 | ENA
Project description:In the present study quantitative real-time PCR was used to determine the expression status of eight imprinted genes (GRB10, H19, IGF2R, XIST, IGF2, NNAT, PEG1 and PEG10) during preimplantation development, in normal fertilized and uniparental porcine embryos. The results demonstrated that, in all observed embryo samples, a non imprinted gene expression pattern up to the 16-cell stage of development was common for most genes. This was true for all classes of embryo, regardless of parental-origins and the direction of imprint. However, several differentially expressed genes (H19, IGF2, XIST and PEG10) were detected amongst the classes at the blastocyst stage of development. Most interestingly and despite the fact that maternally and paternally expressed genes should not be expressed in androgenones and parthenogenones, respectively, both uniparental embryos expressed these genes when tested for in this study. In order to account for this phenomenon, we compared the expression patterns of eight imprinted genes along with the methylation status of the IGF2/H19 DMR3 in haploid and diploid parthenogenetic embryos. Our findings revealed that IGF2, NNAT and PEG10 were silenced in haploid but not diploid parthenogenetic blastocysts and differential methylation of the IGF2/H19 DMR3 was consistently observed between haploid and diploid parthenogenetic blastocysts. These results appear to suggest that there exists a process to adjust the expression status of imprinted genes in diploid parthenogenetic embryos and that this phenomenon may be associated with altered methylation at an imprinting control region. In addition we believe that imprinted expression occurs in at least four genes, namely H19, IGF2, XIST and PEG10 in porcine blastocyst stage embryos.
| S-EPMC3137617 | biostudies-literature
Project description:BackgroundThe high incidence of aneuploidy in early human development, arising either from errors in meiosis or postzygotic mitosis, is the primary cause of pregnancy loss, miscarriage, and stillbirth following natural conception as well as in vitro fertilization (IVF). Preimplantation genetic testing for aneuploidy (PGT-A) has confirmed the prevalence of meiotic and mitotic aneuploidies among blastocyst-stage IVF embryos that are candidates for transfer. However, only about half of normally fertilized embryos develop to the blastocyst stage in vitro, while the others arrest at cleavage to late morula or early blastocyst stages.MethodsTo achieve a more complete view of the impacts of aneuploidy, we applied low-coverage sequencing-based PGT-A to a large series (n = 909) of arrested embryos and trophectoderm biopsies. We then correlated observed aneuploidies with abnormalities of the first two cleavage divisions using time-lapse imaging (n = 843).ResultsThe combined incidence of meiotic and mitotic aneuploidies was strongly associated with blastocyst morphological grading, with the proportion ranging from 20 to 90% for the highest to lowest grades, respectively. In contrast, the incidence of aneuploidy among arrested embryos was exceptionally high (94%), dominated by mitotic aneuploidies affecting multiple chromosomes. In turn, these mitotic aneuploidies were strongly associated with abnormal cleavage divisions, such that 51% of abnormally dividing embryos possessed mitotic aneuploidies compared to only 23% of normally dividing embryos.ConclusionsWe conclude that the combination of meiotic and mitotic aneuploidies drives arrest of human embryos in vitro, as development increasingly relies on embryonic gene expression at the blastocyst stage.
| S-EPMC10544495 | biostudies-literature
Project description:Study questionDoes the oxygen concentration in the culture medium [either physiologic (5%) or atmospheric (20%)] affect mitochondrial ultrastructure and function in preimplantation mouse embryos generated by IVF?Summary answerEmbryos cultured in 20% oxygen show increased mitochondrial abnormalities compared to embryos cultured in 5% oxygen.What is known alreadyART are widely used and have resulted in the birth of more than 8 million children. A variety of media and oxygen concentrations are used to culture embryos. Embryos cultured under physiological O2 tension (5%) reach the blastocyst stage faster and have fewer alterations in gene expression when compared with embryos cultured under atmospheric oxygen conditions (20%). The mechanisms by which oxygen tension affects preimplantation development remain unclear, but mitochondria are believed to play an important role. The aim of this study was to evaluate how mitochondrial ultrastructure and function in IVF embryos were affected by culture under physiologic (5%) or atmospheric (20%) oxygen concentrations.Study design, size, durationZygotes, 2-cell, 4-cell, morula and blastocyst were flushed out of the uterus after natural fertilization and used as controls. IVF was performed in CF1 x B6D2F1 mice and embryos were cultured in Potassium simplex optimized medium (KSOM) with amino acids (KAA) under 5% and 20% O2 until the blastocyst stage. Embryo development with the addition of antioxidants was also tested.Participants/materials, setting, methodsMitochondrial function was assessed by measuring mitochondrial membrane potential, reactive oxygen species (ROS) production, ATP levels, and the expression of selected genes involved in mitochondrial function. Mitochondria ultrastructure was evaluated by transmission electron microscopy (TEM).Main results and the role of chanceEmbryos cultured under 20% O2 had fewer mitochondria and more vacuoles and hooded (abnormal) mitochondria compared to the other groups (P < 0.05). At the blastocyst stage the mitochondria of IVF embryos cultured in 20% O2 had lower mtDNA copy number, a denser matrix and more lamellar cristae than controls. Overall IVF-generated blastocysts had lower mitochondrial membrane potential, higher ROS levels, together with changes in the expression of selected mitochondrial genes (P < 0.05). ATP levels were significantly lower than controls only under 5% O2, with the 20% O2 IVF group having intermediate levels. Unexpectedly, adding antioxidant to the culture medium did not improve development.Large scale dataN/A.Limitations, reasons for cautionFindings in mice embryos might be different from human embryos.Wider implications of the findingsThis study suggests that changes in the mitochondria may be part of the mechanism by which lower oxygen concentration leads to better embryo development and further emphasize the importance of mitochondria as a locus of reprogramming.Study funding/competing interest(s)This study was funded by R01 HD 082039 to PFR, the Department of Life, Health and Environmental Sciences, University of L'Aquila, Italy (RIA 2016-2018) and the Department of Anatomy, Histology, Forensic Medicine and Orthopaedics, La Sapienza University of Rome, Italy (University grants 2016-2017). The authors declare no competing interests.
| S-EPMC7967792 | biostudies-literature
Project description:Sirtuins are a phylogenetically conserved NAD+-dependent protein deacetylase/ADP-ribosyltransferase family implicated in diverse biological processes. Several family members localize to mitochondria, the function of which is thought to determine the developmental potential of preimplantation embryos. We have therefore characterized the role of sirtuins in mouse preimplantation development under in vitro culture conditions. All sirtuin members were expressed in eggs, and their expression gradually decreased until the blastocyst stage. Treatment with sirtuin inhibitors resulted in increased intracellular ROS levels and decreased blastocyst formation. These effects were recapitulated by siRNA-induced knockdown of Sirt3, which is involved in mitochondrial energy metabolism, and in Sirt3-/- embryos. The antioxidant N-acetyl-L-cysteine and low-oxygen conditions rescued these adverse effects. When Sirt3-knockdown embryos were transferred to pseudopregnant mice after long-term culture, implantation and fetal growth rates were decreased, indicating that Sirt3-knockdown embryos were sensitive to in vitro conditions and that the effect was long lasting. Further experiments revealed that maternally derived Sirt3 was critical. Sirt3 inactivation increased mitochondrial ROS production, leading to p53 upregulation and changes in downstream gene expression. The inactivation of p53 improved the developmental outcome of Sirt3-knockdown embryos, indicating that the ROS-p53 pathway was responsible for the developmental defects. These results indicate that Sirt3 plays a protective role in preimplantation embryos against stress conditions during in vitro fertilization and culture.
| S-EPMC2912189 | biostudies-literature