scholarly journals Epigenetic alteration of the donor cells does not recapitulate the reprogramming of DNA methylation in cloned embryos

Reproduction ◽  
2007 ◽  
Vol 134 (6) ◽  
pp. 781-787 ◽  
Author(s):  
Gabbine Wee ◽  
Jung-Jae Shim ◽  
Deog-Bon Koo ◽  
Jung-Il Chae ◽  
Kyung-Kwang Lee ◽  
...  

Epigenetic reprogramming is a prerequisite process during mammalian development that is aberrant in cloned embryos. However, mechanisms that evolve abnormal epigenetic reprogramming during preimplantation development are unclear. To trace the molecular event of an epigenetic mark such as DNA methylation, bovine fibroblasts were epigeneticallyaltered by treatment with trichostatin A (TSA) and then individually transferred into enucleated bovine oocytes. In the TSA-treated cells, expression levels of histone deacetylases and DNA methyltransferases were reduced, but the expression level of histone acetyltransferases such as Tip60 and histone acetyltransferase 1 (HAT1) did not change compared with normal cells. DNA methylation levels of non-treated (normal) and TSA-treated cells were 64.0 and 48.9% in the satellite I sequence (P < 0.05) respectively, and 71.6 and 61.9% in the α-satellite sequence respectively. DNA methylation levels of nuclear transfer (NT) and TSA-NT blastocysts in the satellite I sequence were 67.2 and 42.2% (P < 0.05) respectively, which was approximately similar to those of normal and TSA-treated cells. In the α-satellite sequence, NT and TSA-NT embryos were substantially demethylated at the blastocyst stage as IVF-derived embryos were demethylated. The in vitro developmental rate (46.6%) of TSA-NT embryos that were individually transferred with TSA-treated cells was higher than that (31.7%) of NT embryos with non-treated cells (P < 0.05). Our findings suggest that the chromatin of a donor cell is unyielding to the reprogramming of DNA methylation during preimplantation development, and that alteration of the epigenetic state of donor cells may improve in vitro developmental competence of cloned embryos.

2012 ◽  
Vol 24 (1) ◽  
pp. 119
Author(s):  
Z. Mei-Ling ◽  
Z. Yun-Hai ◽  
T. Yong ◽  
L. Ya ◽  
C. Hong-Guo ◽  
...  

The objective of present study was to investigate the effects of treatments to donor cells with fresh digestion (FD), cryopreservation/thawing (CT), trichostatin A (TSA) and durations of culture using TSA-CR1aa medium on in vitro development of dairy cow cloned embryos. In addition, some somatic cell cloned embryos were transferred to surrogates in heat to evaluate the in vivo developmental competence. The results (Table 1) showed that pretreatment of donor cells using TSA could significantly increase both cleavage and blastocyst rates of embryos (P < 0.05) compared with FD and CT group, whereas no significant difference was found between FD and CT group. When cloned embryos were subjected to TSA treatment in CR1aa for different times (0, 24, 48 and 60 h), the results showed that the blastocyst rate in the 60-h group was the highest (36.11 ± 1.78%) compared with the other groups (P < 0.05). Whereas the reconstructed embryos derived from donor cells treated with TSA for 24 h were continually cultured in TSA for different times (24, 48 and 60 h), the results showed that the blastocyst rate (37.39 ± 1.78%) in the 60-h group was significantly higher than that of the 24-h (25.48 ± 1.34%) group (P < 0.05). Finally, when the cloned embryos from different groups were respectively transferred to 40 natural oestrus recipients, no significant difference in terms of pregnancy rate among groups was found; however, a viable cloned calf was successfully obtained from TSA-treated donor cells and cloned embryo. Therefore, cloned embryos treated with optimized methods can develop to term. Table 1.Pregnancy results established from embryos of different origins


2020 ◽  
Vol 21 (14) ◽  
pp. 4836
Author(s):  
Pil-Soo Jeong ◽  
Bo-Woong Sim ◽  
Soo-Hyun Park ◽  
Min Ju Kim ◽  
Hyo-Gu Kang ◽  
...  

Efficient epigenetic reprogramming is crucial for the in vitro development of mammalian somatic cell nuclear transfer (SCNT) embryos. The aberrant levels of histone H3 lysine 9 trimethylation (H3K9me3) is an epigenetic barrier. In this study, we evaluated the effects of chaetocin, an H3K9me3-specific methyltransferase inhibitor, on the epigenetic reprogramming and developmental competence of porcine SCNT embryos. The SCNT embryos showed abnormal levels of H3K9me3 at the pronuclear, two-cell, and four-cell stages compared to in vitro fertilized embryos. Moreover, the expression levels of H3K9me3-specific methyltransferases (suv39h1 and suv39h2) and DNA methyltransferases (DNMT1, DNMT3a, and DNMT3b) were higher in SCNT embryos. Treatment with 0.5 nM chaetocin for 24 h after activation significantly increased the developmental competence of SCNT embryos in terms of the cleavage rate, blastocyst formation rate, hatching rate, cell number, expression of pluripotency-related genes, and cell survival rate. In particular, chaetocin enhanced epigenetic reprogramming by reducing the H3K9me3 and 5-methylcytosine levels and restoring the abnormal expression of H3K9me3-specific methyltransferases and DNA methyltransferases. Chaetocin induced autophagic activity, leading to a significant reduction in maternal mRNA levels in embryos at the pronuclear and two-cell stages. These findings revealed that chaetocin enhanced the developmental competence of porcine SCNT embryos by regulating epigenetic reprogramming and autophagic activity and so could be used to enhance the production of transgenic pigs for biomedical research.


2016 ◽  
Vol 28 (6) ◽  
pp. 824 ◽  
Author(s):  
M. Saini ◽  
N. L. Selokar ◽  
H. Agrawal ◽  
S. K. Singla ◽  
M. S. Chauhan ◽  
...  

We examined the effects of treating buffalo skin fibroblast donor cells with trichostatin A (TSA), a histone deacetylase (HDAC) inhibitor, and 5-aza-2′-deoxycytidine (5azadC), a DNA methyltransferase (DNMT) inhibitor, on the cells and embryos produced by hand-made cloning. Treatment of donor cells with TSA or 5azadC resulted in altered expression levels of the HDAC1, DNMT1, DNMT3a, P53, CASPASE3 and CASPASE9 genes and global levels of acetylation of lysine at position 9 or 14 in histone 3 (H3K9/14ac), acetylation of lysine at position 5 in histone 4 (H4K5ac), acetylation of lysine at position 18 in histone 3 (H3K18ac) and tri-methylation of lysine at position 27 in histone 3 (H3K27me3). Moreover, global levels of DNA methylation and activity of DNMT1 and HDAC1 were decreased, while global acetylation of H3 and H3K9 was significantly increased in comparison to untreated cells. Simultaneous treatment of donor cells with TSA (50 nM) and 5azadC (7.5 nM) resulted in higher in vitro development to the blastocyst stage, reduction of the apoptotic index and the global level of H3K27 me3 and altered expression levels of HDAC1, P53, CASPASE3, CASPASE9 and DNMT3a in cloned blastocysts. Transfer of cloned embryos produced with donor cells treated with TSA led to the birth of a calf that survived for 21 days. These results show that treatment of buffalo donor cells with TSA and 5azadC improved developmental competence and quality of cloned embryos and altered their epigenetic status and gene expression, and that these beneficial effects were mediated by a reduction in DNA and histone methylation and an increase in histone acetylation in donor cells.


2018 ◽  
Vol 30 (10) ◽  
pp. 1342 ◽  
Author(s):  
Zhao-Bo Luo ◽  
Long Jin ◽  
Qing Guo ◽  
Jun-Xia Wang ◽  
Xiao-Xu Xing ◽  
...  

Accumulating evidence suggests that aberrant epigenetic reprogramming and low pluripotency of donor nuclei lead to abnormal development of cloned embryos and underlie the inefficiency of mammalian somatic cell nuclear transfer (SCNT). The present study demonstrates that treatment with the small molecule RepSox alone upregulates the expression of pluripotency-related genes in porcine SCNT embryos. Treatment with the histone deacetylase inhibitor LBH589 significantly increased the blastocyst formation rate, whereas treatment with RepSox did not. Cotreatment with 12.5 μM RepSox and 50 nM LBH589 (RepSox + LBH589) for 24 h significantly increased the blastocyst formation rate compared with that of untreated embryos (26.9% vs 8.5% respectively; P < 0.05). Furthermore, the expression of pluripotency-related genes octamer-binding transcription factor 4 (NANOG) and SRY (sex determining region Y)-box 2 (SOX2) were found to significantly increased in the RepSox + LBH589 compared with control group at both the 4-cell and blastocyst stages. In particular, the expression of NANOG was 135-fold higher at the blastocyst stage in the RepSox + LBH589 group. Moreover, RepSox + LBH589 improved epigenetic reprogramming. In summary, RepSox + LBH589 increases the expression of developmentally important genes, optimises epigenetic reprogramming and improves the in vitro development of porcine SCNT embryos.


2018 ◽  
Vol 24 (1) ◽  
pp. 29-37 ◽  
Author(s):  
Shuang Liang ◽  
Zheng-Wen Nie ◽  
Jing Guo ◽  
Ying-Jie Niu ◽  
Kyung-Tae Shin ◽  
...  

AbstractMicroRNA (miR)-29b plays a crucial role during somatic cell reprogramming. The aim of the current study was to explore the effects of miR-29b on the developmental competence of bovine somatic cell nuclear transfer (SCNT) embryos, as well as the underlying mechanisms of action. The expression level of miR-29b was lower in bovine SCNT embryos at the pronuclear, 8-cell, and blastocyst stages compared within vitrofertilized embryos. In addition, miR-29b regulates the expression of DNA methyltransferases (Dnmt3a/3bandDnmt1) in bovine SCNT embryos. We further investigated SCNT embryo developmental competence and found that miR-29b overexpression during bovine SCNT embryonic development does not improve developmental potency and downregulation inhibits developmental potency. Nevertheless, the quality of bovine SCNT embryos at the blastocyst stage improved significantly. The expression of pluripotency factors and cellular proliferation were significantly higher in blastocysts from the miR-29b overexpression group than the control and downregulation groups. In addition, outgrowth potential in blastocysts after miR-29b overexpression was also significantly greater in the miR-29b overexpression group than in the control and downregulation groups. Taken together, these results demonstrated that miR-29b plays an important role in bovine SCNT embryo development.


2007 ◽  
Vol 19 (1) ◽  
pp. 168
Author(s):  
V. Zakhartchenko ◽  
F. Yang ◽  
R. Hao ◽  
E. Wolf

Epigenetic status of the genome of a donor nucleus is likely to be associated with the developmental potential of cloned embryos produced by somatic cell nuclear transfer (SCNT). Prevention of epigenetic errors by manipulation of the epigenetic status of donor cells is expected to result in improvement of cloning efficiency. In this study, we transferred cultured rabbit cumulus cells (RCC) and fetal fibroblasts (RFF) from genetically marked rabbits (Ali/Bas) into metaphase II (MII) oocytes and analyzed the levels of histone H3K9 acetylation in donor cells and cloned embryos. We also assessed the correlation between the histone acetylation status of donor cells and cloned embryos and their developmental potential. To test whether alteration of the histone acetylation status affects development of cloned embryos, we treated donor cells with sodium butyrate (NaBu), a histone deacetylase inhibitor. Further, we tried to improve cloning efficiency by chimeric complementation of cloned embryos with one or two blastomeres from in vitro-fertilized or parthenogenetic embryos. Histone acetylation in donor cells and cloned embryos was detected by anti-acH3K9 antibody using Western immunoblot analysis or immunochemistry, respectively. Data were analyzed by chi-square (developmental rates) or Student-Newman-Keuls (histone acetylation) test. The levels of acetylated histone H3K9 were higher in RCCs than in RFFs (P &lt; 0.05). Although the type of donor cells did not affect development to blastocyst, after transfer into recipients, RCC-cloned embryos induced a higher initial pregnancy rate as compared to RFF-cloned embryos (40% vs. 20%; P &lt; 0.05). However, almost all pregnancies with either type of cloned embryos were lost by the middle of gestation and only one fully developed; a live RCC-derived rabbit was obtained. Treatment of RFFs with NaBu significantly (P &lt; 0.05) increased the level of histone H3K9/14 acetylation and the proportion of nuclear transfer embryos developing to blastocyst (49% vs. 33% with non-treated RFF; P &lt; 0.05). The distribution of signals for acH3K9 in either group of cloned embryos did not resemble that in in vivo-fertilized embryos, suggesting that reprogramming of this epigenetic mark is aberrant in cloned rabbit embryos and cannot be corrected by treatment of donor cells with NaBu. Aggregation of embryos cloned from NaBu-treated RFFs with blastomeres from in vivo-derived embryos improved development to blastocyst, but no cloned offspring were obtained. Two live cloned rabbits were produced from this donor cell type only after aggregation of cloned embryos with a parthenogenetic blastomere. Our study demonstrates that the levels of histone acetylation in donor cells and cloned embryos correlate with their developmental potential and can be a useful epigenetic mark to predict efficiency of SCNT rabbits. This work was supported by the Bayerische Forschungsstiftung and by Therapeutic Human Polyclonals, Inc.


2008 ◽  
Vol 20 (1) ◽  
pp. 101 ◽  
Author(s):  
J. Li ◽  
Y. Du ◽  
P. M. Kragh ◽  
S. Purup ◽  
K. Villemoes ◽  
...  

Development to the blastocyst stage following nuclear transfer is dependent on the donor cell's ability to reprogram its genome to a totipotent state. Reprogramming of the transferred somatic nuclei must be completed by the time normal activation of the embryonic genome occurs (Solter 2000 Nat. Rev. Genet. 1, 199–207). Recently, Enright et al. (2003 Biol. Reprod. 69, 896–901) reported that in vitro development of cloned cow embryos was improved by treatment of donor cells with a histone deacetylase inhibitor, TrichostatinA (TSA). So far, there are no reports available for adult pig fibroblast cells treated with TSA. The objective of this study was to investigate whether the development of handmade cloned embryos in pig could be improved by using TSA-treated donor cells. Adult pig fibroblast cells were treated with 100, 150, or 200 nm TSA for 24 h, compared to untreated controls, and were then used as donor cells. The cells were electrofused with handmade enucleated pig oocytes separately and were activated with calcium ionophore and cycloheximide. They were subsequently cultured in porcine zygote medium 3 (PZM-3; Yoshioka et al. 2002 Biol. Reprod. 66, 112–119) using the well of the well system (WOW; Vajta et al. 2000 Mol. Reprod. Dev. 55, 256–264). Experiments were repeated 4 times and the data were analyzed with AVEDEV and t-test in Excel (Microsoft Excel 2007). The cleavage rates and the total cell numbers per blastocyst were similar between groups (P > 0.05), as shown in Table 1. However, the cloned blastocyst rate using donor cells treated with 100 nm TSA was higher than in the other groups (69.9 ± 4.7% v. 43.6 ± 4.3%, 43.1 ± 5.8%, or 46.6 ± 3.6%; P < 0.05), as shown in Table 1. These data suggest that proper TSA treatment for donor cells before somatic cloning improves the rate of development of porcine handmade cloned embryos to the blastocyst stage. Further research is needed to examine the in vivo development of embryos reconstructed with TSA-treated donor cells. Table 1. Developmental ability of cloned pig embryos derived fromTSA-treated donor cells


2016 ◽  
Vol 28 (2) ◽  
pp. 162
Author(s):  
M. Saini ◽  
N. L. Selokar ◽  
H. Agrawal ◽  
S. K. Singla ◽  
M. S. Chauhan ◽  
...  

Somatic cell nuclear transfer (SCNT) is a promising technology in buffalo for multiplication of elite animals, species conservation, and production of transgenic embryos for therapeutic applications. However, the cloning efficiency obtained in this species is very low, which might be due to improper reprogramming of donor cells after SCNT. Treatment of donor cells or fused embryos or both with epigenetic modifiers might be a suitable approach to improve the ability of donor cells to be reprogrammed. The present study was aimed at examining the effects of treatment of donor cells (24 h before SCNT) or fused embryos (10 h post-electrofusion) or both with 50 nM TSA + 7.5 nM 5-aza-dC on the developmental competence, quality, and epigenetic status of buffalo embryos produced by hand-made cloning (HMC) as described earlier (Saini et al. 2014 Reprod. Fertil. Dev. doi: 10.1071/RD14176). The percentage data were analysed using SYSTAT 12.0 (SPSS Inc., Chicago, IL, USA) after arcsine transformation. Differences between means were analysed by one-way ANOVA followed by Fisher’s least significant difference test. The blastocyst rate was significantly higher (P < 0.05) and the apoptotic index was significantly lower (P < 0.05) in embryos produced from donor cells or fused embryos or both treated with TSA + 5-aza-dC than that of controls (Table 1). However, the cleavage rate and the total cell number were not significantly different among all the groups. The global level of H3K18ac, examined by immunofluorescence staining, was higher (P < 0.05) and that of H3K27me3 was lower (P < 0.01) in blastocysts produced from donor cells or fused embryos or both treated with TSA + 5-aza-dC than that of controls. These results show that treatment of donor cells, fused embryos, or both with TSA + 5-aza-dC improves the developmental competence and quality, and alters the epigenetic status of buffalo embryos produced by HMC. However, the effects of treatment with these epigenetic modifiers on the pregnancy rate require further studies. Table 1.Effect of treatment of donor cells, fused embryos, or both with 50 nM TSA + 7.5 nM 5-aza-dC on the developmental competence and level of apoptosis in cloned embryos


2020 ◽  
Vol 98 (2) ◽  
pp. 145-153 ◽  
Author(s):  
Jing Zhang ◽  
Liam J. Hawkins ◽  
Kenneth B. Storey

The wood frog is one of the few freeze-tolerance vertebrates. This is accomplished in part by the accumulation of cryoprotectant glucose, metabolic rate depression, and stress response activation. These may be achieved by mechanisms such as DNA methylation, which is typically associated with transcriptional repression. Hyperglycemia is also associated with modifications to epigenetic profiles, indicating an additional role that the high levels of glucose play in freeze tolerance. We sought to determine whether DNA methylation is affected during freezing exposure, and whether this is due to the wood frog’s response to hyperglycemia. We examined global DNA methylation and DNA methyltransferases (DNMTs) in the liver and muscle of frozen and glucose-loaded wood frogs. The results showed that levels of 5-methylcytosine (5mC) increased in the muscle, suggesting elevated DNA methylation during freezing. DNMT activities also decreased in muscle during thawing, glucose loading, and in vitro glucose experiments. Liver DNMT activities were similar to muscle; however, a varied response to DNMT levels and a decrease in 5mC highlight the metabolic role the liver plays during freezing. Glucose was also shown to decrease DNMT activity levels in the wood frog, in vitro, elucidating a potentially novel regulatory mechanism. Together these results suggest an interplay between freeze tolerance and hyperglycemic regulation of DNA methylation.


2010 ◽  
Vol 22 (6) ◽  
pp. 1041 ◽  
Author(s):  
Clara S. Oliveira ◽  
Naiara Z. Saraiva ◽  
Marcela M. de Souza ◽  
Tatiane A. D. Tetzner ◽  
Marina R. de Lima ◽  
...  

Trichostatin A (TSA) induces histone hyperacetylation by inhibiting histone deacetylases and consequently increasing gene expression. The hypothesis was that TSA supplementation during the in vitro culture (IVC) of bovine embryos would increase the blastocyst rate, particularly in low-quality and female embryos. Oocytes were fertilised separately with X and Y spermatozoa and, 70 h after IVF, the IVC medium was supplemented with 5 nM and 15 nM TSA for 48 or 144 h. Incubation of female embryos with 5 nM and 15 nM TSA resulted in similar increases in acetylated histone H3K9 levels. However, to see comparable effects on acetylated histone H3K9 levels in male embryos, the culture medium needed to be supplemented with 15 nM TSA (as opposed to 5 nM TSA for female embryos). Treatment of male and female embryos with 5 nM TSA for 48 h or female embryos with 5 nM for 144 h had no effect on blastocyst rates, although 15 nM TSA compromised embryonic development. The terminal deoxyribonucleotidyl transferase-mediated dUTP–digoxigenin nick end-labelling (TUNEL) assay revealed increased apoptosis in female embryos treated with 5 nM TSA for 144 h, as well as in male and female embryos treated with 15 nM TSA for 48 h, but this increase in apoptosis was not observed in low-quality embryos. The results of the present study suggest that TSA treatment promotes histone hyperacetylation, but has no beneficial effects on the in vitro production of male and female bovine embryos during preimplantation development.


Sign in / Sign up

Export Citation Format

Share Document