Establishment of Trophectoderm Cell Lines from Buffalo (Bubalus bubalis) Embryos of Different Sources and Examination of In Vitro Developmental Competence, Quality, Epigenetic Status and Gene Expression in Cloned Embryos Derived from Them

Effects of epigenetic modifier on the developmental competence and quantitative expression of genes in male and female buffalo (Bubalus bubalis) cloned embryos

Adult male and female Murrah buffalo fibroblast cells were used as donors for the production of embryos using handmade cloning. Both donor cells and reconstructed embryos were treated with 50 nM trichostatin-A (TSA) and 7.5 nM 5-aza-2'-deoxycytidine (5-aza-dC). The blastocyst rate of both treated male (40.1% ± 2.05) and female (37.0% ± 0.83) embryos was significantly lower than in untreated control males (49.7% ± 3.80) and females (47.2% ± 2.44) but their apoptotic index was lower (male, control: 5.90 ± 0.48; treated: 4.96 ± 0.31): (female, control: 8.11 ± 0.67; treated: 6.65 ± 0.43) and epigenetic status in terms of global acetylation and methylation of histone was significantly improved. The expression level of hypoxanthine-guanine phosphoribosyltransferase (HPRT) was higher (P < 0.05) and that of PGK, G6PD, OCT 4, IFN-tau and CASPASE3 was significantly lower (P < 0.05) in treated male blastocyst than control and the expression levels of DNMT1, IGF1R and BCL-XL were not significantly different between the two groups. In the female embryos, the relative mRNA abundance of OCT4 was significantly higher (P < 0.05), and that of XIST and CASPASE3 was significantly lower (P < 0.05) in the epigenetic modifier-treated group compared with that of the control group, whereas the expression levels of HPRT, PGK, G6PD, DNMT1, IFN-tau, IGF1R and BCL-XL were not significantly different between the two groups. In both embryos, a similar effect of treatment was observed on genes related to growth and development, but the effect on the expression of X-linked genes varied. These results indicate that not all X-linked genes respond to TSA and 5-aza-dC treatment in the same manner.

Production of Water Buffalo SCNT Embryos by Handmade Cloning

Cloning by somatic cell nuclear transfer (SCNT) involves the transfer of a somatic nucleus into an enucleated oocyte followed by chemical activation and embryo culture. Further, handmade cloning (HMC) is a simple and efficient SCNT method for large-scale embryo production. HMC does not require micromanipulators for oocyte enucleation and reconstruction since these steps are carried out using a sharp blade controlled by hand under a stereomicroscope. In this chapter, we review the status of HMC in the water buffalo (Bubalus bubalis) and further describe a protocol for the production of buffalo-cloned embryos by HMC and assays to estimate their quality.

miR-1246 is implicated as a possible candidate for endometrium remodelling facilitating implantation in buffalo (Bubalus bubalis)

BACKGROUND

The microRNAs (miRs) secreted by the trophectoderm (TE) cells have recently been implicated in the conceptus-endometrial cross talk during implantation and placentation. These miRs modulate various cellular processes during conception and throughout the pregnancy by regulating the gene expression in the foetal and maternal tissues.

OBJECTIVES

This study was undertaken to elucidate the function of TE secreted miRNAs in the maternal-foetal cross-talk during implantation/placentation in buffalo.

METHODS

The in vitro produced blastocysts were cultured on a cumulus feeder layer for 21 days. The relative expression profiles of a selected panel of miRs was generated using the spent media collected on Days 0, 7, 12, 16, and 21. A custom-designed mirVana™ miRNA mimic was used to transfect the endometrial epithelial cells (EECs) in order to determine the role of miRNA exhibiting highest expression on Days 21 and 21.

RESULTS

The expression of miR-1246 (p < 0.001) and let-7b (p < 0.01) was found to be significantly higher on Day 21 of TE culture in comparison to the control (Day 0). This elevated expression indicated the involvement of these miRs in the maternal-foetal cross-talk. Interestingly, after the transfection of EECs with miRNA mimic for miR-1246 (a novel molecule vis-à-vis implantation), the expression of beta-catenin and mucin1 in these cells was found to be significantly (p < 0.05) downregulated vis-à-vis the control, that is, the IFN-τ primed EECs (before transfection).

CONCLUSIONS

The TE secreted miR-1246 appeared to lower the expression of the endometrial receptivity genes (mucin1 and beta-catenin) which apparently assists the endometrium in preparing for placentation.

RNAi-mediated knockdown of Xist improves development of the female buffalo (Bubalus bubalis) nuclear transfer embryos

Xist plays a critical role in the X-chromosome inactivation (XCI), an important epigenetic reprogramming of somatic cell nuclear transfer (SCNT) embryos. Modulation of Xist expression enhanced the developmental ability of mouse cloned embryos. However, the roles of Xist in buffalo SCNT embryos remain unknown. In this study, we investigated the methylation and expression status of Xist in different genders of buffalo donor cells and various stages (two-cell, eight-cell, morula and blastocyst) of in vitro fertilization (IVF) and SCNT embryos. The methylation of Xist in SCNT-♀ and SCNT-♂ embryos was aberrant hypomethylation compared with the buffalo foetal fibroblast (♀-BFF and ♂-BFF), IVF-♀ and IVF-♂ embryos. At the eight-cell stage, Xist expression was significantly higher in SCNT-♀ embryos compared with those in SCNT-♂, IVF-♀ and IVF-♂ embryos (P < 0.05). Meanwhile, no significant difference was found between IVF-♀ and IVF-♂ embryos (P > 0.05). Accordingly, we suppressed Xist expression by RNAi-Xist in SCNT-♀ embryos. Results showed that injection of Xist-shRNA significantly improved the morula and blastocyst rates (P < 0.05). These results indicated that correcting the abnormal expression of the Xist gene contributed to the development of SCNT-♀ embryos.

Global DNA methylation profiles of buffalo (Bubalus bubalis) preimplantation embryos produced by handmade cloning and in vitro fertilization

Somatic cell nuclear transfer technique (SCNT) has proved to be an outstanding method of multiplication of elite animals but accompanied with low efficiency and live birth rate of cloned animals. Epigenetic alterations of DNA has been one of the culprits behind this issue. Cloned embryos are found to deviate slightly from regular pattern of demethylation and re-methylation at the time of nuclear reprogramming and embryonic development when compared with embryos produced by in vitro fertilization (IVF). Thus, the present study was aimed at evaluating global DNA methylation profiles of cloned embryos at 2-cell, 8-cell and blastocyst stages and compare it with corresponding stages of embryos produced by IVF by using MeDIP-Sequencing on Illumina-based platform. We found out that cloned embryos exhibited significantly different DNA methylation pattern as compared to IVF embryos with respect to distribution of differentially methylated regions in different components of genome, CpG islands distribution and methylation status, gene ontological profiles and pathways affected throughout the developmental stages. The data generated from MeDIP-Seq was validated at blastocyst stage cloned and IVF embryos by bisulfite-sequencing PCR on five randomly selected gene regions.

Current status of assisted reproductive technologies in buffaloes

Buffaloes are raised by small farm holders primarily as source of draft power owing to its resistance to hot climate, disease, and stress conditions. Over the years, transformation of these animals from draft to dairy was deliberately carried out through genetic improvement program leading to the development of buffalo-based enterprises. Buffalo production is now getting more attention and interest from buffalo raisers due to its socioeconomic impact as well as its contribution to propelling the livestock industry in many developing countries. Reproduction of buffaloes, however, is confronted with huge challenge and concern as being generally less efficient to reproduce compared with cattle due to both intrinsic and extrinsic factors such as poor estrus manifestation, silent heat, marked seasonal infertility, postpartum anestrus, long calving interval, delayed puberty, inherently low number of primordial follicles in their ovaries, high incidence of atresia, and apoptosis. Assisted reproductive technologies (ARTs) are major interventions for the efficient utilization of follicle reserve in buffaloes. The present review focuses on estrus and ovulation synchronization for fixed time artificial insemination, in vitro embryo production, intracytoplasmic sperm injection, cryopreservation of oocytes and embryos, somatic cell nuclear transfer, the factors affecting utilization in various ARTs, and future perspectives in buffaloes.

Effects of treatment with a microRNA mimic or inhibitor on the developmental competence, quality, epigenetic status and gene expression of buffalo (Bubalus bubalis) somatic cell nuclear transfer embryos

Expression levels of 13 microRNAs (miRNAs) were compared between buffalo blastocysts produced by somatic cell nuclear transfer through hand-made cloning and IVF to improve cloning efficiency. Expression of miR-22, miR-145, miR-374a and miR-30c was higher, whereas that of miR-29b, miR-101, miR-302b, miR-34a, miR-21 and miR-25 was lower, in nuclear transferred (NT) than IVF embryos; the expression of miR-200b, miR-26a and miR-128 was similar between the two groups. Based on these, miR-145, which is involved in the regulation of pluripotency, was selected for further investigation of NT embryos. miR-145 expression was lowest at the 2-cell stage, increased through the 4-cell stage and was highest at the 8-cell or morula stage in a pattern that was similar between NT and IVF embryos. miR-145 expression was higher in NT than IVF embryos at all stages examined. Treatment of reconstructed embryos 1h after electrofusion with an inhibitor of miR-145 for 1h decreased the apoptotic index and increased the blastocyst rate, total cell number, ratio of cells in the inner cell mass to trophectoderm, global levels of acetylation of histone 3 at lysine 18 and expression of Krueppel-like factor 4 (KLF4), octamer-binding transcription factor 4 (OCT4) and SRY (sex determining region Y)-box 2 (SOX2) in blastocysts. Treatment with an miR-145 mimic had the opposite effects. In conclusion, treatment of NT embryos with an miR-145 inhibitor improves the developmental competence and quality, and increases histone acetylation and expression of pluripotency-related genes.

Parthenogenetic activation of buffalo (Bubalus bubalis) oocytes: comparison of different activation reagents and different media on their developmental competence and quantitative expression of developmentally regulated genes

This study was carried out to compare the efficacy of different methods to activate buffalo A + B and C + D quality oocytes parthenogenetically and to study the in vitro developmental competence of oocytes and expression of some important genes at the different developmental stages of parthenotes. The percentage of A + B oocytes (62.16 ± 5.06%, range 53.8-71.3%) was significantly higher (P < 0.001) compared with that of C + D oocytes (37.8 ± 5.00%, range 28.6-46.1%) retrieved from slaughterhouse buffalo ovaries. Among all combinations, ethanol activation followed by culture in research vitro cleave medium gave the highest cleavage and blastocyst yields for both A + B and C + D grade oocytes. Total cell numbers, inner cell mass/trophectoderm ratio and apoptotic index of A + B group blastocysts were significantly different (P < 0.05) from their C + D counterpart. To determine the status of expression patterns of developmentally regulated genes, the expression of cumulus-oocyte complexes, fertilization, developmental competence and apoptotic-related genes were also studied in parthenogenetically produced buffalo embryos at different stages, and indicated that the differential expression patterns of the above genes had a role in early embryonic development.

Approaches used to improve epigenetic reprogramming in buffalo cloned embryos

The reproductive cloning in buffalo in India has been started using a simplified somatic cell nuclear transfer technique named handmade cloning. Since the birth of first cloned female buffalo in 2009, a number of buffalo clones have been produced in India by utilizing different types of donor cells such as ear cells, embryonic stem cells, semen somatic cells and urine somatic cells. The use of buffalo cloning on a large scale is restricted due to low pregnancy rates and poor calf survival. Considerable attempts have been made to improve the overall buffalo cloning efficiency, particularly by modifying epigenetic reprogramming of cloned embryos. Previous studies have demonstrated that chemical epigenetic modifiers such as trichostatin A and 5-aza-2’-deoxycytidine, m-carboxycinnamic acid bishydroxamide can be used to treat donor somatic cells and reconstructed fused embryos to correct the epigenetic reprogramming to enhance the overall cloning efficiency in terms of live birth rates.

Synergistic effect of basic fibroblast growth factor (bFGF) and epidermal growth factor on derivation of camel (Camelus dromedarius) trophoblast stem cells

This study aimed to optimize the derivation of trophectoderm from in vitro-produced camel embryos under feeder-free culture conditions using the basement membrane matrix Matrigel. Trophoblastic vesicles were obtained through mechanical microdissection of in vitro-produced camel (Camelus dromedarius) embryos. Supplementing the culture medium with 10 ng/ml of epidermal growth factor and 10 ng/ml fibroblast growth factor improved the attachment and subsequent outgrowths of cultured trophoblastic vesicles when compared with the control group and the groups supplemented individually with each growth factor. The expression levels of pluripotency genes octamer-binding transcription factor 4 (Oct4), sex determining region Y-box 2 (Sox2), myelocytomatosis proto-oncogene (c-Myc) and anti-apoptotic gene B-cell lymphoma 2 (Bcl2) were increased in trophoblastic vesicles supplemented with both growth factors when compared with the control group. Conversely, both growth factors decreased the expression of apoptotic genes tumour protein p53 (p53) and Bcl-2-associated X protein (Bax). To the best of our knowledge, this may be the first report describing the derivation of trophoblast stem cells from in vitro-produced camel embryos.

Buffalo SCNT embryos exhibit abnormal gene expression of ERK/MAPK pathway and DNA methylation

Inhibition of ERK/MAPK pathway has been shown to decrease DNA methylation via down-regulation of DNA methyltransferases (DNMTs) in several studies suggesting that this pathway plays an important role in regulation of DNA methylation. We examined the relative expression level of seven important genes related to ERK/MAPK pathway and DNMTs (DNMT1, DNMT3a and DNMT3b) by quantitative real-time PCR in buffalo blastocysts produced by Hand-made cloning and compared it with that in blastocyst-stage embryos produced by in vitro fertilization (IVF). The expression level of six of seven genes related to ERK/MAPK pathway examined i.e., p21RAS, RAF1, AKT1, ERK2, PIK3R2 and c-Myc was significantly higher (p < 0.05) in cloned than in IVF embryos. However, the expression level of FOS was lower (p < 0.005) in cloned than in IVF embryos. The relative expression level of DNMT3a and DNMT3b but not that of DNMT1 was significantly higher (p < 0.05) in cloned than in IVF embryos. These results indicate that the cloned embryos exhibit an abnormal expression of several important genes related to ERK/MAPK pathway and DNMTs. Although a direct link between ERK/MAPK pathway and DNMTs was not examined in the present study, it can be speculated that ERK/MAPK pathway may have a role in regulating the expression of DNMTs in embryos, as also observed in other tissues.

Effect of Sex of Embryo on Developmental Competence, Epigenetic Status, and Gene Expression in Buffalo (Bubalus bubalis) Embryos Produced by Hand-Made Cloning

Buffalo embryos were produced by hand-made cloning using skin fibroblasts from male and female buffaloes (n = 4 each) as donor cells for examining the effect of sex. Although the rate of blastocyst formation (43.8% ± 1.31% vs. 42.2% ± 1.22%) was similar, the total cell number (333 ± 10.4 vs. 270 ± 10.9) was higher (p < 0.05) whereas the apoptotic index (6.39 ± 0.25 vs. 8.52 ± 0.38) was lower (p < 0.05) for male than for female blastocysts. In the blastocysts, the global level of H3K18ac was found to be in the following order: male>female>IVF (in vitro fertilization) blastocysts (p < 0.05). The global level of H3K9me2 was not significantly different between male and female blastocysts and was higher (p < 0.05) compared with that in their IVF counterparts. The relative mRNA abundance of X-chromosome-linked (XIST, HPRT, PGK, and G6PD), apoptosis- (CASPASE3) and pregnancy-related genes (IFN-τ) was significantly higher (p < 0.05) whereas that of DNMT1 was significantly lower (p < 0.05) in female than in male blastocysts; however, in the case of apoptosis- (BCL-XL) and developmental competence-related genes (IGF1R and OCT4), the expression level was similar between the two groups. The gene expression level of OCT4 and IFN-τ but not of IGF1R was significantly lower (p < 0.05) in cloned than in IVF blastocysts. This study demonstrates that the epigenetic status, quality, and expression level of several genes but not the developmental competence are affected by the sex of cloned embryos.

Recent developments in d-α-tocopheryl polyethylene glycol-succinate-based nanomedicine for cancer therapy

Cancer remains an obstacle to be surmounted by humans. As an FDA-approved biocompatible drug excipient, d-α-tocopheryl polyethylene glycol succinate (TPGS) has been widely applied in drug delivery system (DDS). Along with in-depth analyses of TPGS-based DDS, increasingly attractive results have revealed that TPGS is able to act not only as a simple drug carrier but also as an assistant molecule with various bio-functions to improve anticancer efficacy. In this review, recent advances in TPGS-based DDS are summarized. TPGS can inhibit P-glycoprotein, enhance drug absorption, induce mitochondrial-associated apoptosis or other apoptotic pathways, promote drug penetration and tumor accumulation, and even inhibit tumor metastasis. As a result, many formulations, by using original TPGS, TPGS-drug conjugates or TPGS copolymers, were prepared, and as expected, an enhanced therapeutic effect was achieved in different tumor models, especially in multidrug resistant and metastatic tumors. Although the mechanisms by which TPGS participates in such functions are not yet very clear, considering its effectiveness in tumor treatment, TPGS-based DDS appears to be one of the best candidates for future clinical applications.

Isolation and characterization of the trophectoderm from the Arabian camel (Camelus dromedarius)

We isolated and characterized trophoblast from in vivo-derived camel embryos and compared with embryonic stem-like cells. Camel embryos were flushed on day 8 post-insemination and used to derive trophectoderm and embryonic stem-like cells under feeder-free culture conditions using a basement membrane matrix. Embryos were evaluated for the expression of POU5F1, MYC, KLF4, SOX2, CDX2, and KRT8 mRNA transcripts by relative quantitative polymerase chain reaction. Camel embryos grew and expanded to ∼4.5 mm and maintained their vesicular shape in vitro for 21 days post-insemination. Trophoblast and embryonic stem-like cell lines grew under feeder-free culture conditions and showed distinct morphological criteria and normal chromosomal counts. Embryonic stem-like cells showed positive staining in the alkaline phosphatase reaction. Trophoblast cells showed a significant increase in CDX2, KRT8, KLF4, and SOX2 expression compared with embryonic stem-like cells and whole embryos. Embryonic stem-like cells showed a significant decrease in CDX2 expression and increase in SOX2 and KRT8 expression compared to embryonic expression. POU5F1 and MYC expression showed no difference between embryos and both cell lines. We characterized embryo survival in vitro, particularly the derivation of trophectoderm and embryonic stem-like cells, providing a foundation for further analysis of early embryonic development and placentation in camels.

Treatment of Donor Cells and Reconstructed Embryos with a Combination of Trichostatin-A and 5-aza-2'-Deoxycytidine Improves the Developmental Competence and Quality of Buffalo Embryos Produced by Handmade Cloning and Alters Their Epigenetic Status and Gene Expression

The application of cloning technology on a large scale is limited by very low offspring rate primarily due to aberrant or incomplete epigenetic reprogramming. Trichostatin A (TSA), a histone deacetylase inhibitor, and 5-aza-2'-deoxycytidine (5-aza-dC), an inhibitor of DNA methyltransferases, are widely used for altering the epigenetic status of cloned embryos. We optimized the doses of these epigenetic modifiers for production of buffalo embryos by handmade cloning and examined whether combined treatment with these epigenetic modifiers offered any advantage over treatment with the individual epigenetic modifier. Irrespective of whether donor cells or reconstructed embryos or both were treated with 50 nM TSA +7.5 nM 5-aza-dC, (1) the blastocyst rate was significantly higher (71.6 ± 3.5, 68.3 ± 2.6, and 71.8 ± 2.4, respectively, vs. 43.1 ± 3.4 for controls, p < 0.05); (2) the apoptotic index was lower (5.4 ± 1.1, 9.5 ± 1.0, and 7.4 ± 1.3, respectively, vs. 19.5 ± 2.1 for controls, p < 0.05) and was similar to that of in vitro fertilization blastocysts (6.0 ± 0.8); (3) the global level of H3K18ac was higher (p < 0.01) and that of H3K27me3 lower (p < 0.05) than in controls and was similar among all treatment groups; and (4) the expression level of epigenetic-(HDAC1, DNMT1, and DNMT3a), pluripotency-(OCT4 and NANOG), and development-related (FGF4) genes, but not that of SOX2 and CDX2, was similar among all treatment groups. These results demonstrate that similar levels of beneficial effects can be obtained following treatment of either donor cells or reconstructed embryos or both with the combination of TSA +5-aza-dC. Therefore, there is no advantage in treating both donor cells and reconstructed embryos when the combination of TSA and 5-aza-dC is used.

Proteomic Profile of Mabuya sp. (Squamata: Scincidae) Ovary and Placenta During Gestation

Reptiles are one of the most diverse groups of vertebrates, providing an integrated system for comparative studies on metabolic, animal physiology, and developmental biology. However, the molecular data available are limited and only recently have started to call attention in the "omics" sciences. Mabuya sp. is a viviparous placentrotrophic skink with particular reproductive features, including microlecithal eggs, early luteolysis, prolonged gestation, and development of a highly specialized placenta. This placenta is responsible for respiratory exchange and the transference of all nutrients necessary for embryonic development. Our aim was to identify differentially expressed proteins in the ovary and placenta of Mabuya sp. during early, mid, and late gestation; their possible metabolic pathways; and biological processes. We carried out a comparative proteomic analysis during gestation in both tissues by sodium dodecyl sulfate polyacrylamide gel electrophoresis, two-dimensional gel electrophoresis, and matrix-assisted laser desorption/ionization. Differential protein expression in both tissues (Student's t-test P < 0.05) was related to several processes such as cell structure, cell movement, and energy. Proteins found in ovary are mainly associated with follicular development and its regulation. In the placenta, particularly during mid and late gestation, protein expression is involved in nutrient metabolism, transport, protein synthesis, and embryonic development. This work provides new insights about the proteins expressed and their physiological mechanisms in Mabuya sp. placenta and ovary during gestation.