Genome editing tools such as the clustered regularly interspaced short palindromic repeat (CRISPR)-associated system (Cas) have been widely used to modify genes in model systems including animal zygotes and human cells, and hold tremendous promise for both basic research and clinical applications. To date, a serious knowledge gap remains in our understanding of DNA repair mechanisms in human early embryos, and in the efficiency and potential off-target effects of using technologies such as CRISPR/Cas9 in human pre-implantation embryos. In this report, we used tripronuclear (3PN) zygotes to further investigate CRISPR/Cas9-mediated gene editing in human cells. We found that CRISPR/Cas9 could effectively cleave the endogenous β-globin gene (HBB). However, the efficiency of homologous recombination directed repair (HDR) of HBB was low and the edited embryos were mosaic. Off-target cleavage was also apparent in these 3PN zygotes as revealed by the T7E1 assay and whole-exome sequencing. Furthermore, the endogenous delta-globin gene (HBD), which is homologous to HBB, competed with exogenous donor oligos to act as the repair template, leading to untoward mutations. Our data also indicated that repair of the HBB locus in these embryos occurred preferentially through the non-crossover HDR pathway. Taken together, our work highlights the pressing need to further improve the fidelity and specificity of the CRISPR/Cas9 platform, a prerequisite for any clinical applications of CRSIPR/Cas9-mediated editing.
Blastocyst ; CRISPR-Cas Systems ; Hemoglobins, Abnormal ; genetics ; metabolism ; Humans ; Zygote

OBJECTIVETo analyze sex chromosome mosaicisms in early cleavage-stage human embryos and blastocysts with poor embryo quality score based on the numbers of pronucleus(PN) zygotes using X,Y dual color fluorescence in situ hybridization (FISH), and to discuss the possible mechanisms.

METHODSFresh or frozen-thawed early cleavage-stage human embryos and blastocysts with poor embryo quality score not suitable for embryo transfer were studied with dual color FISH.

RESULTSDouble signal rate of 2PN among early cleavage-stage embryos was 66.67%, which was significantly higher than 1PN and 3PN embryos. Single signal rate of 1PN early cleavage-stage embryos was 90.41%, which was significantly higher than 2PN and 3PN ones. Three signal rate of 3PN early cleavage-stage embryos was 28.00%, which was significantly higher than 1PN and 2PN ones. Double signal rate of 3PN ones was 46.00%, which was significantly higher than 1PN ones. The polyploid rate of frozen-thawed early cleavage-stage embryos was 23.53%, which was slightly higher than that of fresh embryos, but with no statistical significance. The mosaicism rate of 24 blastocysts was 100.00% and the double signal dominant (≥ 50%) rate was 62.50%, which was significantly higher than the rate of early cleavage-stage embryos.

CONCLUSIONUsing 2PN as the criterion for embryo quality score cannot guarantee the selection of normal fertilized embryo for transplantation. Frozen-thawed embryos may harbor more polyploid cells. To avoid the selection of embryos with abnormal chromosomes, combinations of pre-implantation genetic diagnosis (PGD) and prenatal diagnosis are necessary. Meanwhile, blastocysts with poor quality scores may provide an important source for embryo stem cells.

Blastocyst ; metabolism ; Cleavage Stage, Ovum ; metabolism ; Fertilization in Vitro ; Humans ; In Situ Hybridization, Fluorescence ; Mosaicism ; embryology ; Sex Chromosomes

Human pluripotent stem cells provide an inexhaustible model to study human embryogenesis in vitro. Recent studies have provided diverse models to generate human blastoids by self-organization of different pluripotent stem cells or somatic reprogramming intermediates. However, whether blastoids can be generated from other cell types or whether they can recapitulate postimplantation development in vitro is unknown. Here, we develop a strategy to generate human blastoids from heterogeneous intermediates with epiblast, trophectoderm, and primitive endoderm signatures of the primed-to-naïve conversion process, which resemble natural blastocysts in morphological architecture, composition of cell lineages, transcriptome, and lineage differentiation potential. In addition, these blastoids reflect many features of human peri-implantation and pregastrulation development when further cultured in an in vitro 3D culture system. In summary, our study provides an alternative strategy to generate human blastoids and offers insights into human early embryogenesis by modeling peri- and postimplantation development in vitro.
Humans ; Pluripotent Stem Cells/metabolism* ; Embryo, Mammalian/metabolism* ; Cell Differentiation ; Blastocyst ; Cell Lineage ; Embryonic Development

OBJECTIVE: Under estrogen deficiency, blastocysts cannot initiate implantation and enter dormancy. Dormant blastocysts live longer in utero than normal blastocysts, and autophagy has been suggested as a mechanism underlying the sustained survival of dormant blastocysts during delayed implantation. Autophagy is a cellular degradation pathway and a central component of the integrated stress response. Reactive oxygen species (ROS) are produced within cells during normal metabolism, but their levels increase dramatically under stressful conditions. We investigated whether heightened autophagy in dormant blastocysts is associated with the increased oxidative stress under the unfavorable condition of delayed implantation. METHODS: To visualize ROS production, day 8 (short-term dormancy) and day 20 (long-term dormancy) dormant blastocysts were loaded with 1-microM 5-(and-6)-chloromethyl-2', 7'-dichlorodihydrofluorescein diacetate, acetyl ester (CM-H2DCFDA). To block autophagic activation, 3-methyladenine (3-MA) and wortmannin were used in vivo and in vitro, respectively. RESULTS: We observed that ROS production was not significantly affected by the status of dormancy; in other words, both dormant and activated blastocysts showed high levels of ROS. However, ROS production was higher in the dormant blastocysts of the long-term dormancy group than in those of the short-term group. The addition of wortmannin to dormant blastocysts in vitro and 3-MA injection in vivo significantly increased ROS production in the short-term dormant blastocysts. In the long-term dormant blastocysts, ROS levels were not significantly affected by the treatment of the autophagy inhibitor. CONCLUSION: During delayed implantation, heightened autophagy in dormant blastocysts may be operative as a potential mechanism to reduce oxidative stress. Further, ROS may be one of the potential causes of compromised developmental competence of long-term dormant blastocysts after implantation.
Animals ; Autophagy* ; Blastocyst* ; Estrogens ; Mental Competency ; Metabolism ; Mice* ; Oxidative Stress ; Reactive Oxygen Species*

We developed a detailed electroporation method to deliver efficiently siRNA into mouse preimplantation embryos. By introducing Cy3 labeled negative control small interfering RNA (siRNA) into mouse preimplantation embryos, we optimized conditions for the electroporation, including the voltage, pulse duration, pulse number, electroporation buffer and an important step to weaken the zona pellucida. Embryonic survival rate, transfection rate and blastocyst development rate were evaluated under the converted fluorescence microscope, by embryos counting and statistical analysis. The best transfection was achieved in opti-MEM under the conditions of 30 V, 1 ms, 3 pulses, and the duration of digestion in tyrode's solution was 10 s. In conclusion, the proposed electroporation approach here is a simple and efficient tool to deliver siRNA for RNA interference (RNAi) into mouse preimplantation embryos.
Animals ; Blastocyst ; metabolism ; Electroporation ; Female ; Male ; Mice ; RNA Interference ; RNA, Small Interfering ; genetics ; Transfection ; methods

Animals ; Blastocyst ; Embryo Loss ; HeLa Cells ; Humans ; Mice ; Nuclear Proteins ; deficiency ; genetics ; metabolism

OBJECTIVETo study the expression of gene associated with retinoid-interferon-induced mortality-19(GRIM-19) in preimplantation embryo of mice and explore its role in embryonic development.

METHODSThe protein and mRNA expressions of GRIM-19 in 2-cell, 4-cell, 8-cell, morula, and blastocyst phases of mice preimplantation embryo were detected by Western blot analysis and Real-time polymerase chain reaction (PCR).

RESULTSGRIM-19 was continuously expressed in every stage of preimplantation embryo of mice. Western blot analysis and Real-time PCR demonstrated a gradual increase of GRIM-19 expression from 2-cell, which reached a peak in 8-cell phase and then decreased progressively.

CONCLUSIONSThe expression of GRIM-19 in mouse preimplantation embryos changes as at different developmental phases. GRIM-19 may play an important role during embryonic development.

Animals ; Blastocyst ; drug effects ; metabolism ; Female ; Interferons ; pharmacology ; Mice ; NADH, NADPH Oxidoreductases ; genetics ; metabolism ; Pregnancy ; RNA, Messenger ; genetics ; Tretinoin ; pharmacology

OBJECTIVETo investigate the significance of trophinin expression in human oocytes and preimplantation embryos.

METHODSThe expression of trophinin in 9 human oocytes, 16 blastomeres and 12 blastocysts were detected by indirect immunofluorescence assay and observed under laser scanning confocal microscope.

RESULTSHuman oocytes, blastomeres and blastocysts were all positive for trophinin expression, and the positivity intensified significantly in the course of the embryonic development (P<0.05).

CONCLUSIONTrophinin may play an important role in human embryo implantation by mediating homophilic adhesion between the embryo and the endometrium during the implantation window.

Blastocyst ; metabolism ; Cell Adhesion Molecules ; biosynthesis ; Female ; Fluorescent Antibody Technique, Indirect ; Humans ; Microscopy, Confocal ; Oocytes ; metabolism ; Pregnancy

Mouse blastocysts were exposed to doses of 0, 1 and 10 mumol/L retinoic acid (RA) for 24 h and the cytotoxic effect of RA on the mouse blastocysts in vitro was observed. FITC-labeled terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL-FITC) assay was employed to stain apoptotic cells and immunohistochemical S-P staining method was used to detect the expression of Fas protein in mouse blastocysts in vitro. The results showed that RA could induce apoptosis and increase the expression of Fas proteins of trophectoderm (TE) and inner cell mass (ICM) cells in blastocysts. Compared with the findings for the control blastocysts, exposure to RA (10 mumol/L) resulted in a more significant apoptosis and higher expression level of Fas proteins (P<0.01). It was concluded that RA could induce apoptosis, which may result in a significant reduction in the average number of total cells and the trophectoderm/inner cell mass in blastocysts and an increased expression of Fas protein, suggesting that RA had a cytotoxic effect on the growth and development of early embryos in mice.
Antigens, CD95/*biosynthesis ; Apoptosis/*drug effects ; Blastocyst/cytology ; Blastocyst/*metabolism ; Cell Culture Techniques/methods ; Cells, Cultured ; Gene Expression Regulation/*drug effects ; In Situ Nick-End Labeling ; RNA, Messenger/metabolism ; Tretinoin/*pharmacology

OBJECTIVETo correlate sperm nucleoprotein transition (SNT) with sperm morphology, DNA damage and embryo development, and assess its value for assisted reproductive technology (ART).

METHODSThe SNT of 437 infertile men underwent ART were assayed, and its correlation with sperm morphology, DNA damage, fertilization rate, normal fertilization rate, cleavage rate, available embryo rate, D3 high quality embryo rate, blastocyst formation rate and high quality blastocyst rate were analyzed.

RESULTSThe normal morphology rate of sperms, DNA damage, fertilization rate, normal fertilization rate, cleavage rate, embryo transfer rate (ETR), D3 high quality embryo rate, blastocyst formation rate (BFR) and high quality blastocyst in normal males (Group A, abnormal rate≤30%, 135 subjects) did not significantly differ from those with an abnormal rate between 30% and 60% (Group B, 170 subjects) (P>0.05). For those with an abnormal rate of above 60% (Group C, 132 subjects), the sperm normal morphology rate, DNA damage, normal fertilization rate, ETR, D3 high quality embryo rate, high quality blastocyst rate were significantly lower compared with Group A (P<0.01), while no significant difference was found in fertilization rate, cleavage rate and BFR between groups A and C (P>0.05).

CONCLUSIONSNT is related with sperm morphology rate, DNA damage and embryo development, and should be assessed before ART.

Adult ; Blastocyst ; metabolism ; DNA Damage ; Embryo Transfer ; Embryonic Development ; Female ; Fertilization in Vitro ; Humans ; Infertility, Male ; genetics ; metabolism ; Male ; Nucleoproteins ; genetics ; metabolism ; Spermatozoa ; metabolism