• Asian-Australasian Journal of Animal Sciences
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• v.30 no.7
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• pp.944-949
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• 2017

Objective: Investigated the effect and mechanism of ascorbic acid on the development of porcine embryos produced by somatic cell nuclear transfer (SCNT). Methods: Porcine embryos were produced by SCNT and cultured in the presence or absence of ascorbic acid. Ten-eleven translocation 3 (TET3) in oocytes was knocked down by siRNA injection. After ascorbic acid treatment, reprogramming genes were analyzed by realtime reverse transcription-polymerase chain reaction (RT-PCR). Furthermore, relative 5-methylcytosine and 5-hydroxymethylcytosine content in pronucleus were detected by realtime PCR. Results: Ascorbic acid significantly increased the development of porcine embryos produced by SCNT. After SCNT, transcript levels of reprogramming genes, Pou5f1, Sox2, and Klf were significantly increased in blastocysts. Furthermore, ascorbic acid reduced 5-methylcytosine content in pronuclear embryos compared with the control group. Knock down of TET3 in porcine oocytes significantly prevents the demethylation of somatic cell nucleus after SCNT, even if in the presence of ascorbic acid. Conclusion: Ascorbic acid enhanced the development of porcine SCNT embryos via the increased TET3 mediated demethylation of somatic nucleus.

• Journal of Animal Reproduction and Biotechnology
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• v.35 no.1
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• pp.86-93
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• 2020

The establishment of porcine embryonic stem cells (ESCs) from porcine somatic cell nuclear transfer (SCNT) blastocysts is influenced by in vitro culture day of porcine reconstructed embryo and feeder cell type. Therefore, the objective of the present study was to determine the optimal in vitro culture period for reconstructed porcine SCNT embryos and mouse embryonic fibroblast (MEF) feeder cell type for enhancing colony formation efficiency from the inner cell mass (ICM) of porcine SCNT blastocysts and their outgrowth. As the results, porcine SCNT blastocysts produced through in vitro culture of the reconstructed embryos for 8 days showed significantly increased efficiency in the formation of colonies, compared to those for 7 days. Moreover, MEF feeder cells derived from outbred ICR mice showed numerically the highest efficiency of colony formation in blastocysts produced through in vitro culture of porcine SCNT embryos for 8 days and porcine ESCs with typical ESC morphology were maintained more successfully over Passage 2 on outbred ICR mice-derived MEF feeder cells than on MEF feeder cells derived from inbred C57BL/6 and hybrid B6CBAF1 mice. Overall, the harmonization of porcine SCNT blastocysts produced through in vitro culture of the reconstructed embryos for 8 days and MEF feeder cells derived from outbred ICR mice will greatly contribute to the successful establishment of ESCs derived from porcine SCNT blastocysts.

• Reproductive and Developmental Biology
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• v.33 no.1
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• pp.13-18
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• 2009

The aim of this study was to examine the microtubule distributions of somatic cell nuclear transfer (SCNT) and parthenogenetic porcine embryos. Porcine SCNT embryos were produced by fusion of serum-starved fetal fibroblast cells with enucleated oocytes. Reconstituted and mature oocytes were activated by electric pulses combined with 6-dimethlyaminopurine treatment. SCNT and parthenogenetic embryos were cultured in vitro for 6 days. Microtubule assembly of embryos was examined by confocal microscopy 1 hr and 20 hr after fusion or activation, respectively. The proportions of embryos developed to the blastocyst stage were 25.7% and 30.4% in SCNT and parthenogenetic embryos, respectively. The frequency of embryos showing $\beta$-tubulins was 81.8% in parthenogenetic embryos, whereas 31.3% in SCNT embryos 1 hr after activation or fusion. The frequency of the embryos underwent normal mitotic phase was low in SCNT embryos (40.6%) compared to that of parthenogenetic ones (59.7%) 20 hr after fusion or activation (p<0.05). The rate of SCNT embryos with an abnormal mitosis pattern is about twice compared to that of parthenogenetic ones. The spindle assembly and its distribution of SCNT embryos in the first mitotic phase were not different from those of parthenogenetic ones. The result shows that although microtubule distribution of porcine SCNT embryos shortly after fusion is different from parthenogenetic embryos, and the frequency of abnormal mitosis 20 hr after fusion or activation is slightly increased in SCNT embryos, microtubule distributions at the first mitotic phase are similar in both SCNT and parthenogenetic embryos.

• Reproductive and Developmental Biology
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• v.38 no.4
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• pp.147-158
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• 2014

Differentiated nuclei can experimentally be returned to an undifferentiated embryonic status after nuclear transfer (NT) to unfertilized metaphase II (MII) oocytes. Nuclear reprogramming is triggered immediately after somatic cell nucleus transfer (SCNT) into recipient cytoplasm and this period is regarded as a key stage for optimizing reprogramming. In a recent study (Dai et al., 2010), use of m-carboxycinnamic acid bishydroxamide (CBHA) as a histone deacetylase inhibitor during the in vitro early culture of murine cloned embryos modifies the acetylation status of somatic nuclei and increases the developmental competence of SCNT embryos. Thus, we examined the effects of CBHA treatment on the in vitro preimplantation development of porcine SCNT embryos and on the acetylated status of histone H3K9 on cloned embryos at the zygote stage. We performed the three groups SCNT: SCNT (NT), CBHA treatment at the porcine fetus fibroblast cells (PFFs) used as donor cells prior to SCNT (CBHA-C) and CBHA treatment at the porcine SCNT embryos during the in vitro early culture after oocyte activation (CBHA-Z). The PFFs were treated with a $15{\mu}M$ of CBHA (8 h) for the early culture and the porcine cloned embryos were treated with a $100{\mu}M$ concentration of CBHA during the in vitro early culture (10 h). Cleavage rates and development to the blastocyst stage were assessed. No significant difference was observed the cleavage rate among the groups (82.6%, 76.4% and 82.2%, respectively). However, the development competence to the blastocyst stage was significantly increased in CBHA-Z embryos (22.7%) as compared to SCNT and CBHA-C embryos (8.6% and 4.1%)(p<0.05). Total cell numbers and viable cell numbers at the blastocyst stage of porcine SCNT embryos were increased in CBHA-Z embryos as compared to those in CBHA-C embryos (p<0.05). Signal level of histone acetylation (H3K9ac) at the zygote stage of SCNT was increased in CBHA-Z embryos as compared to SCNT and CBHA-C embryos. The results of the present study suggested that treatment with CBHA during the in vitro early culture (10 h) had significantly increased the developmental competence and histone acetylation level at the zygote stage.

• Journal of Animal Reproduction and Biotechnology
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• v.34 no.2
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• pp.130-138
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• 2019

Although somatic cell nuclear transfer (SCNT)-derived embryonic stem cells (ESCs) in pigs have great potential, their use is limited because the establishment efficiency of ESCs is extremely low. Accordingly, we tried to develop in-vitro culture system stimulating production of SCNT blastocysts with high performance in the colony formation and formation of colonies derived from SCNT blastocysts for enhancing production efficiency of porcine ESCs. For these, SCNT blastocysts produced in various types of embryo culture medium were cultured in different ESC culture medium and optimal culture medium was determined by comparing colony formation efficiency. As the results, ICM of porcine SCNT blastocysts produced through sequential culture of porcine SCNT embryos in the modified porcine zygote medium (PZM)-5 and the PZM-5F showed the best formation efficiency of colonies in α-MEM-based medium. In conclusion, appropriate combination of the embryo culture medium and ESC culture medium will greatly contribute to successful establishment of ESCs derived from SCNT embryos.

• Development and Reproduction
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• v.22 no.1
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• pp.73-83
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• 2018

This study investigates the endoplasmic reticulum (ER) stress and subsequent apoptosis in duced during somatic cell nuclear transfer (SCNT) process of porcine SCNT embryos. Porcine SCNT and in vitro fertilization (IVF) embryos were sampled at 3 h and 20 h after SCNT or IVF and at the blastocyst stage for mRNA extraction. The x-box binding protein 1 (Xbp1) mRNA and the expressions of ER stress-associated genes were confirmed by RT-PCR or RT-qPCR. Apoptotic gene expression was analyzed by RT-PCR. Before commencing SCNT, somatic cells treated with tunicamycin (TM), an ER stress inducer, confirmed the splicing of Xbp1 mRNA and increased expressions of ER stress-associated genes. In all the embryonic stages, the SCNT embryos, when compared with the IVF embryos, showed slightly increased expression of spliced Xbp1 (Xbp1s) mRNA and significantly increased expression of ER stress-associated genes (p<0.05). In all stages, apoptotic gene expression was slightly higher in the SCNT embryos, but not significantly different from that of the IVF embryos except for the Bax/Bcl2L1 ratio in the 1-cell stage (p<0.05). The result of this study indicates that excessive ER stress can be induced by the SCNT process, which induce apoptosis of SCNT embryos.

• Journal of Animal Science and Technology
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• v.66 no.4
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• pp.726-739
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• 2024

This study was conducted to investigate whether lysophosphatidic acid (LPA) could improve the development of porcine somatic cell nuclear transfer (SCNT) embryos. Porcine SCNT-derived embryos were cultured in chemically defined polyvinyl alcohol (PVA)-based porcine zygote medium (PZM)-4 without or with LPA, and the development, cell proliferation potential, apoptosis, and expression levels of pluripotent markers were evaluated. LPA significantly increased the rates of cleavage and blastocyst formation compared to those seen in the LPA un-treatment (control) group. The expression levels of embryonic development-related genes (IGF2R, PCNA and CDH1) were higher (p < 0.05) in the LPA treatment group than in the control group. LPA significantly increased the numbers of total, inner cell mass and EdU (5-ethynyl-2'-deoxyuridine)-positive cells in porcine SCNT blastocysts compared to those seen in the control group. TUNEL assay showed that LPA significantly reduced the apoptosis rate in porcine SCNT-derived embryos; this was confirmed by decreases (p < 0.05) in the expression levels of pro-apoptotic genes, BAX and CASP3, and an increase (p < 0.05) in the expression level of the anti-apoptotic gene, BCL2L1. In addition, LPA significantly increased Oct4 expression at the gene and protein levels. Together, our data suggest that LPA improves the quality and development of porcine SCNT-derived embryos by reducing apoptosis and enhancing cell proliferation and pluripotency.

• Journal of Embryo Transfer
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• v.23 no.4
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• pp.245-250
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• 2008

This study was designed to investigate the effect of essential amino acids (EAA) and/or non-essential amino acids (NEAA) on the development of parthenogenetic and somatic cell nuclear transfer (SCNT) porcine embryos in vitro. To evaluate the timing of amino acids supplementation, activated oocytes were cultured in NCSU23-PVA with EAA, NEAA or NEAA+EAA (AAs) during specific periods as below: EAA, NEAA or AAs were supplemented during Day 0 to 6 (whole culture period: ALL), Day 2 to Day 6 (post-maternal embryonic transition period: POST-MET), Day 5 to Day 6 (post-compaction period: POST-CMP), Day 0 to Day 2 (pre-maternal embryonic transition period: PRE-MET), or Day 0 to Day 4 (post-compaction period: PRE-CMP). Supplementation of NEAA decreased cleavage rates in PRE-MET and PRE-CMP and also decreased blastocyst rates in POST-CMP. On the other hand, EAA significantly enhanced blastocyst formation rate in POST-MET and no detrimental effect on embryonic development in other groups. Interestingly, NEAA and EAA had synergistic effect when they were supplemented to the medium during whole culture period. Supplementation of AAs also enhanced SCNT porcine embryo development whereas BSA-free medium without AAs could not supported blastocyst formation of SCNT embryos. In conclusion, existence of EAA and NEAA in defined culture medium variously influences the development of parthenogenetic and SCNT porcine embryos, and their positive effect are only occurred when both EAA and NEAA are supplemented to the medium during whole culture period. Additionally, AAs supplementation enhances the blastocyst formation of SCNT porcine embryos when they are cultured in the defined condition.

• Reproductive and Developmental Biology
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• v.34 no.2
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• pp.73-79
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• 2010

We investigated the microtubule dynamics, including the inheritance of donor centrosomes and the mitotic spindle assembly occurring during the first mitosis of somatic cell nuclear transfer (SCNT) embryos in pigs. SCNT embryos were fixed 15 min and 1 h after fusion in order to assess the inheritance pattern of the donor centrosome. The distribution and dynamic of the centrosome and microtubule during the first mitotic phase of SCNT embryos were also evaluated. The frequency of embryos evidencing $\gamma$-tubulin spots (centrosome) was 93.2% in the SCNT embryos 15 min after fusion. In the majority of the SCNT embryos (61.5%), however, no centrosome was observed 1 h after fusion. The frequency of the embryos with no or abnormal mitotic spindles 20 h after fusion was 19.6%. The $\gamma$-tubulin spots were detected near the nuclei of somatic cells regardless of cell cycle phase, whereas $\gamma$-tubulin spots in the SCNT embryos were observed only during the inter-anaphase transition. These results showed that the donor centrosome is inherited into the SCNT embryos, but failed to assemble the normal mitotic spindles during first mitotic phase in some SCNT embryos.

• Reproductive and Developmental Biology
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• v.31 no.2
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• pp.83-90
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• 2007

Insulin-like growth factor II (IGF2) and H19 genes are mutually imprinted genes which may be responsible for abnormalities in the cloned fetuses and offspring. This study was performed to identify putative differentially methylated regions (DMRs) of porcine H19 locus and to explore its genomic imprinting in in vitro fertilized (IVF) and somatic cell nuclear transferred (SCNT) embryos. Based on mice genomic data, we identified DMRs on H19 and found porcine H19 DMRs that included three CTCF binding sites. Methylation patterns in IVF and SCNT embryos at the 2-, 4-, $8{\sim}16$-cells and blastocyst stages were analyzed by BS (Bisulfite Sequencing)-PCR. The CpGs in CTCF1 was significantly unmethylated in the 2-cell stage IVF embryos. However, the 4- (29.1%) and $8{\sim}16$-cell (68.2%) and blastocyst (48.2%) stages showed higher methylation levels (p<0.01). On the other hand, SCNT embryos were unmethylayted ($0{\sim}2%$) at all stages of development. The CpGs in CTCF2 showed almost unmethylation levels at the 2-,4- and $8{\sim}16$-cell and blastocyst stages of development in both IVF ($0{\sim}14.1%$) and SCNT ($0{\sim}6.4%$) embryos. At all stages of development, CTCF3 was unmethylated in IVF ($0{\sim}17.3%$) and SCNT ($0{\sim}1.2%$) embryos except at the blastocyst stage (54.5%) of IVF embryos. In conclusion, porcine SCNT embryos showed an aberrant methylation pattern comprised to IVF embryos. Therefore, we suggest that the aberrant methylation pattern of H19 loci may be a reason for increased abnormal fetus after embryo transfer of porcine SCNT embryos.