ACADL-YAP axis activity in non-small cell lung cancer carcinogenicity

BACKGROUND

The role of Acyl-CoA dehydrogenase long chain (ACADL) in different tumor types had different inhibiting or promoting effect. However, its role in non-small cell lung cancer (NSCLC) carcinogenicity is not clear.

METHOD

In this study, we utilized The Cancer Genome Atlas (TCGA) database to analyze ACADL expression in NSCLC and its correlation with overall survival. Furthermore, we investigated the function of ACADL on cellular proliferation, invasion, colony, apoptosis, cell cycle in vitro with NSCLC cells. Mechanistically, we evaluated the regulatory effect of ACADL expression on its downstream factor yes-associated protein (YAP) by assessing YAP phosphorylation levels and its cellular localization. Finally, we verified the tumorigenic effect of ACADL on NSCLC cells through xenograft experiments in vivo.

RESULTS

Compared to adjacent non-cancerous samples, ACADL significantly down-regulated in NSCLC. Overexpression of ACADL, effectively reduced the proliferative, colony, and invasive capabilities of NSCLC cells, while promoting apoptosis and inducing cell cycle arrest. Moreover, ACADL overexpression significantly enhanced YAP phosphorylation and hindered its nuclear translocation. However, the inhibitory effect of the overexpression of ACADL in NSCLC cells mentioned above can be partially counteracted by YAP activator XMU-MP-1 application both in vitro and in vivo.

CONCLUSION

The findings suggest that ACADL overexpression could suppress NSCLC development by modulating YAP phosphorylation and limiting its nuclear shift. This role of ACADL-YAP axis provided novel insights into NSCLC carcinogenicity and potential therapeutic strategies.

Human embryos derived from first polar body nuclear transfer exhibit comparatively abnormal morphokinetics during development

OBJECTIVE

Reconstructed oocytes after polar body genome transfer constitute a potential therapeutic option for patients with a history of embryo fragmentation and advanced maternal age. However, the rescue of genetic material from the first polar body (PB1) through introduction into the donor cytoplasm is not yet ready for clinical application.

METHODS

Eighty-five oocytes were obtained following in vitro maturation (IVM) and divided into two groups: PB1 nuclear transfer (PB1NT; n=54) and control (n=31). Following enucleation and PB1 genomic transfer, PB1 fusion was assessed. Subsequently, all fused oocytes underwent intracytoplasmic sperm injection (ICSI) and were cultured in an incubator under a time-lapse monitoring system to evaluate fertilization, embryonic morphokinetic parameters, and cleavage patterns.

RESULTS

Following enucleation and fusion, 77.14% of oocytes survived, and 92.59% of polar bodies (PBs) fused. However, the normal fertilization rate was lower in the PB1NT group than in the control group (56.41% vs. 92%, p=0.002). No significant differences were observed in embryo kinetics between the groups, but a significant difference was detected in embryo developmental arrest after the four-cell stage, along with abnormal cleavage division in the PB1NT group. This was followed by significant between-group differences in the implantation potential rate and euploidy status. Most embryos in the PB1NT group had at least one abnormal cleavage division (93.3%, p=0.001).

CONCLUSION

Fresh PB1NT oocytes successfully produced normal zygotes following PB fusion and ICSI in IVM oocytes. However, this was accompanied by low efficiency in developing into cleavage embryos, along with an increase in abnormal cleavage patterns.

Mouse Cloning Using Outbred Oocyte Donors and Nontoxic Reagents

Somatic cell nuclear transfer (SCNT) technology has become a useful tool for animal cloning, gene manipulation, and genomic reprogramming research. However, the standard mouse SCNT protocol remains expensive, labor-intensive, and requires hard work for many hours. Therefore, we have been trying to reduce the cost and simplify the mouse SCNT protocol. This chapter describes the methods to use low-cost mouse strains and steps from the mouse cloning procedure. Although this modified SCNT protocol will not improve the success rate of mouse cloning, it is a cheaper, simpler, and less tiring method that allows us to perform more experiments and obtain more offspring with the same working time as the standard SCNT protocol.

The mitochondrial challenge: Disorders and prevention strategies

This short review provides basic knowledge on mitochondrial inheritance, its disorders, and potential ways to overcome them in human reproductive medicine. The latter are currently mostly associated with the so-called mitochondrial replacement (nuclear transfer) procedures, performed at different stages and with slight technical differences. Being promising but obviously highly invasive, these procedures require detailed investigation of their delayed effects on embryogenesis, pregnancy and future health. A special attention is paid to the newest available data on these issues, as well as to their limitations and possible further research directions.

Production of Cloned Pigs by Handmade Cloning

Somatic cell nuclear transfer (SCNT) in pigs is a promising technology in biomedical research by association with transgenesis for xenotransplantation and disease modeling technologies. Handmade cloning (HMC) is a simplified SCNT method that does not require micromanipulators and facilitates the generation of cloned embryos in large quantities. As a result of HMC fine-tuning for porcine-specific requirements of both oocytes and embryos, HMC has become uniquely efficient (>40% blastocyst rate, 80-90% pregnancy rates, 6-7 healthy offspring per farrowing, and with negligible losses and malformations). Therefore, this chapter describes our HMC protocol to obtain cloned pigs.

Historical DNA Manipulation Overview

The history of DNA manipulation for the creation of genetically modified animals began in the 1970s, using viruses as the first DNA molecules microinjected into mouse embryos at different preimplantation stages. Subsequently, simple DNA plasmids were used to microinject into the pronuclei of fertilized mouse oocytes and that method became the reference for many years. The isolation of embryonic stem cells together with advances in genetics allowed the generation of gene-specific knockout mice, later on improved with conditional mutations. Cloning procedures expanded the gene inactivation to livestock and other non-model mammalian species. Lentiviruses, artificial chromosomes, and intracytoplasmic sperm injections expanded the toolbox for DNA manipulation. The last chapter of this short but intense history belongs to programmable nucleases, particularly CRISPR-Cas systems, triggering the development of genomic-editing techniques, the current revolution we are living in.

Pluripotent stem cells related to embryonic disc exhibit common self-renewal requirements in diverse livestock species

Despite four decades of effort, robust propagation of pluripotent stem cells from livestock animals remains challenging. The requirements for self-renewal are unclear and the relationship of cultured stem cells to pluripotent cells resident in the embryo uncertain. Here, we avoided using feeder cells or serum factors to provide a defined culture microenvironment. We show that the combination of activin A, fibroblast growth factor and the Wnt inhibitor XAV939 (AFX) supports establishment and continuous expansion of pluripotent stem cell lines from porcine, ovine and bovine embryos. Germ layer differentiation was evident in teratomas and readily induced in vitro. Global transcriptome analyses highlighted commonality in transcription factor expression across the three species, while global comparison with porcine embryo stages showed proximity to bilaminar disc epiblast. Clonal genetic manipulation and gene targeting were exemplified in porcine stem cells. We further demonstrated that genetically modified AFX stem cells gave rise to cloned porcine foetuses by nuclear transfer. In summary, for major livestock mammals, pluripotent stem cells related to the formative embryonic disc are reliably established using a common and defined signalling environment.

This article has an associated ‘The people behind the papers’ interview.

Summary: We report the derivation of similar, stable and continuously expandable pluripotent stem cells related to embryonic disc epiblast from embryos of pig, sheep and cow.

Dynamic reprogramming and function of RNA N6-methyladenosine modification during porcine early embryonic development

N6-Methyladenosine (m6A) regulates oocyte-to-embryo transition and the reprogramming of somatic cells into induced pluripotent stem cells. However, the role of m6A methylation in porcine early embryonic development and its reprogramming characteristics in somatic cell nuclear transfer (SCNT) embryos are yet to be known. Here, we showed that m6A methylation was essential for normal early embryonic development and its aberrant reprogramming in SCNT embryos. We identified a persistent occurrence of m6A methylation in embryos between 1-cell to blastocyst stages and m6A levels abruptly increased during the morula-to-blastocyst transition. Cycloleucine (methylation inhibitor, 20 mM) treatment efficiently reduced m6A levels, significantly decreased the rates of 4-cell embryos and blastocysts, and disrupted normal lineage allocation. Moreover, cycloleucine treatment also led to higher levels in both apoptosis and autophagy in blastocysts. Furthermore, m6A levels in SCNT embryos at the 4-cell and 8-cell stages were significantly lower than that in parthenogenetic activation (PA) embryos, suggesting an abnormal reprogramming of m6A methylation in SCNT embryos. Correspondingly, expression levels of m6A writers (METTL3 and METTL14) and eraser (FTO) were apparently higher in SCNT 8-cell embryos compared with their PA counterparts. Taken together, these results indicated that aberrant nuclear transfer-mediated reprogramming of m6A methylation was involved in regulating porcine early embryonic development.

Glucose in a maturation medium with reduced NaCl improves oocyte maturation and embryonic development after somatic cell nuclear transfer and in vitro fertilization in pigs

This study was conducted to examine whether glucose in maturation medium containing reduced NaCl could improve oocyte maturation and embryonic development in pigs. The base medium was bovine serum albumin-free porcine zygote medium (PZM)-3 containing 10% (v/v) pig follicular fluid (FPZM) or 0.1% (w/v) polyvinyl alcohol (PPZM). Using each medium, the effects of NaCl concentrations (108 and 61.6 mM) and 5.56 mM glucose supplementation (designated as PZM108N, PZM108G, PZM61N, and PZM61G, respectively) were examined using a 2 × 2 factorial arrangement. When oocytes were matured in FPZM, glucose supplementation improved nuclear maturation compared with no supplementation, regardless of the NaCl concentrations. FPZM61G showed a higher blastocyst formation compared with FPZM108N and FPZM108G after parthenogenesis (PA). Blastocyst formations of somatic cell nuclear transfer (SCNT) embryos derived from FPZM61N and FPZM61G were higher compared with those of oocytes from FPZM108N. When oocytes were matured in PPZM, glucose added to PPZM108 and PPZM61 increased nuclear maturation compared with no supplementation. However, glucose added to PPZM108 did not alter embryonic development after PA. Additionally, oocytes matured in PPZM61G showed a higher blastocyst formation compared with those from PPZM61N. In SCNT, blastocyst formation was not influenced by glucose supplementation of PPZM108, but was increased by maturation in glucose-supplemented PPZM61. In embryonic development of in vitro fertilization (IVF), oocytes matured in medium with reduced NaCl and glucose showed significantly higher blastocyst formation compared with those matured in PPZM108G. Our results demonstrated that glucose in maturation medium containing 61.6 mM NaCl increased oocyte maturation and embryonic development after PA, SCNT, and IVF.

Removal of remodeling/reprogramming factors from oocytes and the impact on the full-term development of cloned embryos

The reason for the poor development of cloned embryos is not yet clear. Several reports have suggested that some nuclear remodeling/reprogramming factors (RRFs) are removed from oocytes at the time of enucleation, which might cause the low success rate of animal cloning. However, there is currently no method to manipulate the amount of RRFs in oocytes. Here, we describe techniques we have developed to gradually reduce RRFs in mouse oocytes by injecting somatic cell nuclei into oocytes. These injected nuclei were remodeled and reprogrammed using RRFs, and then RRFs were removed by subsequent deletion of somatic nuclei from oocytes. The size of the metaphase II spindle reduced immediately, but did recover when transferred into fresh oocytes. Though affected, the full-term developmental potential of these RRF-reduced oocytes with MII-spindle shrinkage was not lost after fertilization. When somatic cell nuclear transfer was performed, the successful generation of cloned mice was somewhat improved and abnormalities were reduced when oocytes with slightly reduced RRF levels were used. These results suggest that a change in RRFs in oocytes, as achieved by the method described in this paper or by enucleation, is important but not the main reason for the incomplete reprogramming of somatic cell nuclei.

Generation of goats by nuclear transfer: a retrospective analysis of a commercial operation (1998-2010)

At LFB USA, Inc., the ultimate use for transgenic cloned goats is for the production of recombinant human protein therapeutics in their milk. This retrospective analysis of the Somatic Cell Nuclear Transfer (SCNT) program, spanning from 1998 to 2010, examined parameters potentially affecting the outcomes and efficiencies in this commercial operation. Over 37,000 + ova were utilized in the SCNT protocol producing a total of 203 cloned goats. Fifty one (51) clones were produced from non-transfected (transgenic and non-transgenic animal donor) cell lines and 152 clones were produced from transfected cell lines. Comparisons and summaries of (a) transfected versus non-transfected cell lines, (b) relationship of SCNT parameters to offspring produced, (c) skin versus fetal cells, (d) fresh versus cryopreserved cells, (e) parameters from all cell lines used versus those producing SCNT offspring, (f) variation among cell sources, (g) methods of SCNT parturition management and effects on live offspring, and lastly (h) SCNT variation by program are reported. Findings indicate that (a) non-transfected cell lines were more efficient versus transfected cell lines in generating viable cloned offspring on a per reconstructed embryo transferred basis, (b) transfected fetal fibroblasts had improved efficiency versus transfected skin fibroblasts, (c) the percentage of non-transfected cell lines that produced offspring was statistically higher than transfected cell lines, (d) and induction of parturition improved the percentage of viable offspring. In summary, this retrospective analysis on the SCNT process has identified certain parameters for improved efficiency in producing viable cloned goats in a commercial setting.

Effect of season on the in-vitro maturation and developmental competence of buffalo oocytes after somatic cell nuclear transfer

Somatic cell nuclear transfer (SCNT) is a valuable technology tool with various uses in transgenic animals, regenerative medicine, and stem cell research. However, the efficiency of SCNT embryos appears to have poor developmental competency. Environmental issues may adversely affect SCNT embryos in buffalo. Thereafter, the present study aimed to explore the effect of season on the maturation of buffalo oocytes and subsequent developmental capability after parthenogenetic activation and SCNT in buffalo. Buffalo oocytes (n = 6353) were collected from local slaughterhouse at various seasons; spring (March-April), summer (May-August), autumn (September-November), and winter (December-January). A significant increase (p < 0.05) was recorded in the maturation rate (57.07%) at autumn compared with spring, summer, and winter (50.46, 50.93, and 50.66%, respectively). No significant differences were recorded in the fusion and the cleavage rates among all seasons. Blastocyst development rate was higher (p < 0.05) in autumn and winter (16.52 ± 8.45% and 15.98 ± 7.17%, respectively) than in spring and summer (9.47 ± 6.71% and 10.84 ± 6.58%, respectively) seasons. It could be concluded that the season had a significant effect on oocyte development competence which can be used for SCNT in buffalo.

Functional consequences of mitochondrial mismatch in reconstituted embryos and offspring

Animal cloning technology has been developed to produce progenies genetically identical to a given donor cell. However, in nuclear transfer protocols, the recipient oocytes contribute a heritable mitochondrial genomic (mtDNA) background to the progeny. Additionally, a small amount of donor cell-derived mitochondria accompanies the transferred nucleus in the process; hence, the mtDNAs of two origins are mixed in the cytoplasm (heteroplasmy) of the reconstituted oocyte. Herein, I would like to introduce some of our previous results concerning five key considerations associated with animal cloning, including: mtDNA heteroplasmy in somatic cell nuclear transferred (SCNT) animals, the variation in the transmission of mtDNA heteroplasmy to subsequent generations SCNT cows and pigs, the influence of mtDNA sequence differences on mitochondrial proteins in SCNT cows and pigs, the effects of the introduction of mitochondria derived from somatic cells into recipient oocytes on embryonic development, and alterations of mtDNA heteroplasmy in inter/intraspecies nuclear transfer embryos.

Reducing the cytoplasmic volume during hand-made cloning adversely affects the developmental competence and quality, and alters relative abundance of mRNA transcripts and epigenetic status of buffalo (Bubalus bubalis) embryos

Hand-made cloning (HMC) is a method of choice for somatic cell nuclear transfer (SCNT). There is 20% to 50% of cytoplasm lost during manual enucleation of oocytes with HMC. To compensate, two enucleated demicytoplasts, instead of one, are fused with each donor cell, which leads to cytoplasm pooling from two different demicytoplasts. In this study, effects of using one, instead of two demicytoplasts (controls) was examined, for production of embryos using HMC. Use of one demicytoplast decreased blastocyst development (12.7 ± 1.98% compared with 47.6 ± 3.49%, P < 0.001), total cell number (TCN, 167.6 ± 14.66 compared with 335.9 ± 58.96, P < 0.01), apoptotic index (2.11 ± 0.38 compared with 3.43±0.38, P < 0.05) but did not significantly alter inner cell mass:trophectoderm cell number ratio (0.17 ± 0.01 compared with 0.19 ± 0.02) and the global content of H3K9ac and H3K27me3 of blastocysts, compared to controls. There were gene expression alterations in pluripotency- (SOX2 and NANOG but not OCT4), epigenetic- (DNMT1 but not DNMT3a and HDAC1), apoptosis- (CASPASE3 but not BCL-2 and BAX), trophectoderm- (CDX2), development- (G6PD but not GLUT1) and cell cycle check point control-related related genes (P53) compared with controls. Transfer of cloned blastocysts from one demicytoplast (n = 8) to recipients resulted in a live calf birth that after 12 days died whereas, with transfer of control blastocysts (n = 14) there was birth of a healthy calf. In conclusion, use of one, instead of two demicytoplasts for HMC, compromises in vitro developmental competence, and alters expression of several important genes affecting embryo development.

Comparative analysis of buffalo (Bubalus bubalis) non-transgenic and transgenic embryos containing human insulin gene, produced by SCNT

Somatic cell nuclear transfer (SCNT), using transgenic donor cells, is a highly efficient method for producing transgenic embryos. We compared the developmental competence, quality and gene expression of transgenic embryos produced by Hand-made cloning from buffalo fetal fibroblasts (BFFs) containing human insulin gene, with non-transgenic embryos produced from BFFs (Controls). The expression vector (pAcISUBC), constructed by inserting human insulin gene between DNA fragments containing mammary gland-specific buffalo β-lactoglobulin (buBLG) promoter and terminator buBLG 3'UTR regions into pAcGFP-N1 vector, was used for obtaining the 11 kb insert for transfection of BFFs by nucleofection. Presence of the transgene in embryos was confirmed by examining GFP expression by RT-PCR and immunofluorescence. The blastocyst rate was lower (P < 0.05) for transgenic embryos than for controls (35.7 ± 1.8% vs 48.7 ± 2.4%). The apoptotic index was higher (P < 0.05) for transgenic than for control blastocysts which, in turn, was higher (P < 0.05) than for IVF counterparts (6.9 ± 0.9, 3.8 ± 0.5 and 1.8 ± 0.3, respectively). The total cell number was similar for transgenic and non-transgenic blastocysts (143.2 ± 17.0 and 137.2 ± 7.6, respectively). The expression level of pro-apoptotic genes BAX and BID but not that of CASP3 and CASP9, and cell cycle check point control-related gene P53 was higher (P < 0.05), and that of development- (IGF-1R and G6PD) and pluripotency-related gene NANOG was lower (P < 0.05) in transgenic than in control embryos. The expression level of epigenetic-related genes DNMT1, DNMT3a and HDAC1 and pluripotency-related gene OCT4 was similar in the two groups. The expression level of BAX, BID, CASP9, P53, DNMT1 and DNMT3a was higher (P < 0.05) and that of OCT4, NANOG IGF-1R and G6PD was lower (P < 0.05) in cloned transgenic than in IVF blastocysts whereas, that of CASP3 and HDAC1 was similar between the two groups. In conclusion, these results suggest that transgenic embryos produced by SCNT have lower developmental competence and quality, and altered gene expression compared to non-transgenic embryos.

Various nuclear reprogramming systems using egg and oocyte materials

Maternal factors stored in eggs and oocytes are necessary for reprogramming sperm for embryonic development. This reprogramming activity of maternal factors also works towards somatic cells, including terminally differentiated cells. Several different experimental systems utilizing egg and oocyte materials have been applied to study nuclear reprogramming by maternal factors. Among these systems, the most widely used is the transfer of a somatic cell nucleus to an oocyte arrested at the metaphase II stage, leading to the production of a cloned animal. Nuclear transfer to an unfertilized oocyte thus provides a unique opportunity to examine reprogramming processes involved in acquiring totipotency. Other experimental systems are also available to study maternal reprogramming, such as nuclear transfer to Xenopus laevis oocytes at the germinal vesicle stage, treatment with extracts obtained from eggs or oocytes, and induced pluripotency with overexpressed maternal factors. Each system can be used for answering different types of scientific questions. This review describes currently available reprogramming systems using egg and oocyte materials and discusses how we can deepen our understanding of reprogramming mechanisms by taking advantage of these various experimental systems.

Potential Clinical Applications of Stem Cells in Regenerative Medicine

The field of regenerative medicine is looking for a pluripotent/multipotent stem cell able to differentiate across germ layers and be safely employed in therapy. Unfortunately, with the exception of hematopoietic stem/progenitor cells (HSPCs) for hematological applications, the current clinical results with stem cells are somewhat disappointing. The potential clinical applications of the more primitive embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs) have so far been discouraging, as both have exhibited several problems, including genomic instability, a risk of teratoma formation, and the possibility of rejection. Therefore, the only safe stem cells that have so far been employed in regenerative medicine are monopotent stem cells, such as the abovementioned HSPCs or mesenchymal stem cells (MSCs) isolated from postnatal tissues. However, their monopotency, and therefore limited differentiation potential, is a barrier to their broader application in the clinic. Interestingly, results have accumulated indicating that adult tissues contain rare, early-development stem cells known as very small embryonic-like stem cells (VSELs), which can differentiate into cells from more than one germ layer. This chapter addresses different sources of stem cells for potential clinical application and their advantages and problems to be solved.

Effects of fusion-activation interval and embryo aggregation on in vitro and in vivo development of bovine cloned embryos

Nuclear reprogramming in somatic cell cloning is one of the key factors for proper development, with variations in the protocol appearing to improve cloning efficiency. This study aimed to determine the effects of two fusion-activation intervals and the aggregation of bovine cloned embryos on subsequent in vitro and in vivo development. Zygotes produced by handmade cloning were exposed to two fusion-activation intervals (2 h or 4 h), and then cultured in microwells either individually (1 × 100%) or after aggregation of two structures (2 × 100%). Zona-intact oocytes and zona-free oocytes and hemi-oocytes were used as parthenote controls under the same fusion-activation intervals. Day-7 cloned blastocysts were transferred to synchronous recipients. Cleavage (Day 2), blastocyst (Day 7) and pregnancy (Day 30) rates were compared by the χ² test (P < .05). Extending fusion-activation interval from 2 to 4 h reduced cleavage (91.0 vs. 74.4%) but not blastocyst (34.8 vs. 42.0%) rates. On a microwell basis, cloned embryo aggregation (2 × 100%) increased cleavage (91.5% vs. 74.4%) and blastocyst (46.0% vs. 31.3%) rates compared to controls (1 × 100%), but did not improve the overall embryo production efficiency on Day 7 (23.0% vs. 31.3%), on a per reconstructed embryo basis, respectively. Treatments had no effects on in vitro developmental kinetics, embryo quality, and in vivo development. In summary, the fusion-activation interval and/or the aggregation of cloned bovine embryos did not affect cloning efficiency based on the in vitro development to the blastocyst stage and on pregnancy outcome.

Improvement of Mouse Cloning from Any Type of Cell by Nuclear Injection

Somatic cell nuclear transfer (SCNT) technology has become a useful tool for animal cloning, gene manipulation, and genomic reprograming research. The original SCNT was performed using cell fusion between the donor cell and oocyte. This method remains very popular, but we have recently developed an alternative method that relies on nuclear injection rather than cell fusion. The advantages of nuclear injection include a shortened experimental procedure and reduced contamination of donor cytoplasm in the oocyte. In particular, only this method allows us to perform SCNT using dead cells or naked nuclei such as those from cadavers or body wastes. This chapter describes a basic protocol for the production of cloned mice by the nuclear injection method using a piezo-actuated micromanipulator as well as our recent advances in SCNT using noninvasively collected donor cells such as urine-derived somatic cells. This technique will greatly help not only SCNT but also other forms of micromanipulation, including sperm microinjection into oocytes and embryonic stem cell injection into blastocysts.

Aberrant imprinting in mouse trophoblast stem cells established from somatic cell nuclear transfer-derived embryos

Although phenotypic abnormalities frequently appear in the placenta following somatic cell nuclear transfer (SCNT), mouse trophoblast stem cells (TSCs) established from SCNT embryos reportedly show no distinct abnormalities compared with those derived from normal fertilization. In this study, we reexamined SCNT-TSCs to identify their imprinting statuses. Placenta-specific maternally imprinted genes (Gab1, Slc38a4, and Sfmbt2) consistently showed biallelic expression in SCNT-TSCs, suggesting their loss of imprinting (LOI). The LOI of Gab1 was associated with decreased DNA methylation, and that of Sfmbt2 was associated with decreased DNA methylation and histone H3K27 trimethylation. The maternal allele of the intergenic differentially methylated region (IG-DMR) was aberrantly hypermethylated following SCNT, even though this region was prone to demethylation in TSCs when established in a serum-free chemically defined medium. These findings indicate that the development of cloned embryos is associated with imprinting abnormalities specifically in the trophoblast lineage from its initial stage, which may affect subsequent placental development.

An update: Reproductive handmade cloning of water buffalo (Bubalus bubalis)

The first birth of a cloned animal produced through the Handmade cloning (HMC) technique was reported more than 15 years ago in cattle. This method of somatic cell nuclear transfer (SCNT) has subsequently been evolving as a much simpler alternative to the classical micromanipulator-based SCNT. Several farm animal species such as cattle, buffalo, pigs, sheep, and goats have been successfully cloned using HMC. In buffalo, HMC technique is now well established, and several births of cloned calves have been reported by us. Several factors such as source of somatic cells, quality of recipient oocytes, cell cycle stage prior to SCNT, electrofusion and culture conditions, and epigenetic status of somatic cells, have been optimized leading to the production of good quality cloned embryos. The preservation through cloning of proven breeding bulls that have died by producing live offspring using somatic cells isolated from frozen semen as donor cells and birth of a cloned calf from urine-derived cells are impressive examples of the success of HMC in buffalo. In conclusion, HMC is a valued reproductive technique in buffalo that offers the opportunity to make multiple copies of highly valuable animals, particularly proven breeding bulls. In this review, there is a discussion of the advancement of the HMC technique in buffalo and factors responsible for the efficient production of cloned embryos.

Compensating human subjects providing oocytes for stem cell research: 9-year experience and outcomes

PURPOSE

Human oocytes are arguably one of the most important cell types in humans, yet they are one of the least investigated cells. Because oocytes are limited in number, the use of high-quality oocytes is almost entirely in reproduction. Furthermore, regulatory hurdles for research on gametes and regulations on funding related to research on gametes present significant obstacles to research and the advancement of reproductive treatments. Here we report the outcomes of the largest compensated oocyte donation program for research in the USA to date, and probably worldwide.

METHODS

Women who participated in oocyte donation for research between 2008 and 2017 were contacted in a phone interview and completed a standardized questionnaire.

RESULTS

Of 114 participants, 98 oocyte donors completed donation, donating 1787 mature MII oocytes and a total of 86 skin biopsies. Complication rate, including minor complications, of oocyte donation was 8/98, or 8.1%, for which two involved follow-up. Fifty-seven donors answered questions about their experience. Participants were incentivized primarily by money and a desire to help others and reported an overall favorable experience. Most, but not all, human subjects recalled that they had donated for research, and approximately half recalled that their oocytes were being used specifically for stem cell research.

CONCLUSIONS

Compensated oocyte donation provides a reliable path to obtaining high-quality oocytes for research and is reviewed favorably by oocyte donors. The continuation of programs that offer compensation for oocyte donation is invaluable to continued progress and advancements in stem cell research and human embryology, and for the advancement of novel reproductive treatments.

Depletion of nuclear import protein karyopherin alpha 7 (KPNA7) induces mitotic defects and deformation of nuclei in cancer cells

Background

Nucleocytoplasmic transport is a tightly regulated process carried out by specific transport machinery, the defects of which may lead to a number of diseases including cancer. Karyopherin alpha 7 (KPNA7), the newest member of the karyopherin alpha nuclear importer family, is expressed at a high level during embryogenesis, reduced to very low or absent levels in most adult tissues but re-expressed in cancer cells.

Methods

We used siRNA-based knock-down of KPNA7 in cancer cell lines, followed by functional assays (proliferation and cell cycle) and immunofluorescent stainings to determine the role of KPNA7 in regulation of cancer cell growth, proper mitosis and nuclear morphology.

Results

In the present study, we show that the silencing of KPNA7 results in a dramatic reduction in pancreatic and breast cancer cell growth, irrespective of the endogenous KPNA7 expression level. This growth inhibition is accompanied by a decrease in the fraction of S-phase cells as well as aberrant number of centrosomes and severe distortion of the mitotic spindles. In addition, KPNA7 depletion leads to reorganization of lamin A/C and B1, the main nuclear lamina proteins, and drastic alterations in nuclear morphology with lobulated and elongated nuclei.

Conclusions

Taken together, our data provide new important evidence on the contribution of KPNA7 to the regulation of cancer cell growth and the maintenance of nuclear envelope environment, and thus deepens our understanding on the impact of nuclear transfer proteins in cancer pathogenesis.

Electronic supplementary material

The online version of this article (10.1186/s12885-018-4261-5) contains supplementary material, which is available to authorized users.

Reprogramming of Aged Cells into Pluripotent Stem Cells by Nuclear Transfer

Stem cells have the potential to differentiate into specialized cell types under specific conditions in vivo or in vitro, which are used to cure many diseases related to aging. Somatic cell nuclear transfer (SCNT) can reprogram differential somatic cells into cloned embryos and embryonic stem cells can be derived from these cloned embryos. Recipient oocytes have healthier mitochondria and can improve the metabolism competence, lessen the ROS damage, and rejuvenate mitochondrial function of aged cells during reprogramming. Here, we describe a protocol to isolate aged somatic cells and reprogram them into embryonic stem cells by SCNT. These stem cells can be used to differentiate into regenerative somatic cells and replace the aged cells.

Live birth derived from oocyte spindle transfer to prevent mitochondrial disease

Mutations in mitochondrial DNA (mtDNA) are maternally inherited and can cause fatal or debilitating mitochondrial disorders. The severity of clinical symptoms is often associated with the level of mtDNA mutation load or degree of heteroplasmy. Current clinical options to prevent transmission of mtDNA mutations to offspring are limited. Experimental spindle transfer in metaphase II oocytes, also called mitochondrial replacement therapy, is a novel technology for preventing mtDNA transmission from oocytes to pre-implantation embryos. Here, we report a female carrier of Leigh syndrome (mtDNA mutation 8993T > G), with a long history of multiple undiagnosed pregnancy losses and deaths of offspring as a result of this disease, who underwent IVF after reconstitution of her oocytes by spindle transfer into the cytoplasm of enucleated donor oocytes. A male euploid blastocyst wasobtained from the reconstituted oocytes, which had only a 5.7% mtDNA mutation load. Transfer of the embryo resulted in a pregnancy with delivery of a boy with neonatal mtDNA mutation load of 2.36-9.23% in his tested tissues. The boy is currently healthy at 7 months of age, although long-term follow-up of the child's longitudinal development remains crucial.

Reconstruction of mammalian oocytes by germinal vesicle transfer: A systematic review

Nuclear transfer procedures have been recently applied for clinical and research targets as a novel assisted reproductive technique and were used for increasing the oocyte activity during its growth and maturation. In this review, we summarized the nuclear transfer technique for germinal vesicle stage oocytes to reconstruct the maturation of them. Our study covered publications between 1966 and August 2017. In result utilized germinal vesicle transfer techniques, fusion, and fertilization survival rate on five different mammalian species are discussed, regarding their potential clinical application. It seems that with a study on this method, there is real hope for effective treatments of old oocytes or oocytes containing mitochondrial problems in the near future.

Reprogramming towards totipotency is greatly facilitated by synergistic effects of small molecules

Animal cloning has been achieved in many species by transplanting differentiated cell nuclei to unfertilized oocytes. However, the low efficiencies of cloning have remained an unresolved issue. Here we find that the combination of two small molecules, trichostatin A (TSA) and vitamin C (VC), under culture condition with bovine serum albumin deionized by ion-exchange resins, dramatically improves the cloning efficiency in mice and 15% of cloned embryos develop to term by means of somatic cell nuclear transfer (SCNT). The improvement was not observed by adding the non-treated, rather than deionized, bovine serum. RNA-seq analyses of SCNT embryos at the two-cell stage revealed that the treatment with TSA and VC resulted in the upregulated expression of previously identified reprogramming-resistant genes. Moreover, the expression of early-embryo-specific retroelements was upregulated by the TSA and VC treatment. The enhanced gene expression was relevant to the VC-mediated reduction of histone H3 lysine 9 methylation in SCNT embryos. Our study thus shows a simply applicable method to greatly improve mouse cloning efficiency, and furthers our understanding of how somatic nuclei acquire totipotency.

Summary: The optimized culture condition with small molecules is sufficient to allow highly efficient mouse cloning by removing epigenetic barriers to reprogramming.

Search for KPNA7 cargo proteins in human cells reveals MVP and ZNF414 as novel regulators of cancer cell growth

Karyopherin alpha 7 (KPNA7) belongs to a family of nuclear import proteins that recognize and bind nuclear localization signals (NLSs) in proteins to be transported to the nucleus. Previously we found that KPNA7 is overexpressed in a subset of pancreatic cancer cell lines and acts as a critical regulator of growth in these cells. This characteristic of KPNA7 is likely to be mediated by its cargo proteins that are still mainly unknown. Here, we used protein affinity chromatography in Hs700T and MIA PaCa-2 pancreatic cancer cell lines and identified 377 putative KPNA7 cargo proteins, most of which were known or predicted to localize to the nucleus. The interaction was confirmed for two of the candidates, MVP and ZNF414, using co-immunoprecipitation, and their transport to the nucleus was hindered by siRNA based KPNA7 silencing. Most importantly, silencing of MVP and ZNF414 resulted in marked reduction in Hs700T cell growth. In conclusion, these data uncover two previously unknown human KPNA7 cargo proteins with distinct roles as novel regulators of pancreatic cancer cell growth, thus deepening our understanding on the contribution of nuclear transport in cancer pathogenesis.

Barriers for Deriving Transgene-Free Pig iPS Cells with Episomal Vectors

To date no authentic embryonic stem cell (ESC) line or germline-competent-induced pluripotent stem cell (iPSC) line has been established for large animals. Despite this fact, there is an impression in the field that large animal ESCs or iPSCs are as good as mouse counterparts. Clarification of this issue is important for a healthy advancement of the stem cell field. Elucidation of the causes of this failure in obtaining high quality iPSCs/ESCs may offer essential clues for eventual establishment of authentic ESCs for large animals including humans. To this end, we first generated porcine iPSCs using nonintegrating replicating episomal plasmids. Although these porcine iPSCs met most pluripotency criteria, they could neither generate cloned piglets through nuclear transfer, nor contribute to later stage chimeras through morula injections or aggregations. We found that the reprogramming genes in iPSCs could not be removed even under negative selection, indicating they are required to maintain self-renewal. The persistent expression of these genes in porcine iPSCs in turn caused differentiation defects in vivo. Therefore, incomplete reprogramming manifested by a reliance on sustained expression of exogenous-reprogramming factors appears to be the main reason for the inability of porcine iPSCs to form iPSC-derived piglets.

Efficient TALEN-mediated myostatin gene editing in goats

Background

Myostatin (MSTN) encodes a negative regulator of skeletal muscle mass that might have applications for promoting muscle growth in livestock. In this study, we aimed to test whether targeted MSTN editing, mediated by transcription activator-like effector nucleases (TALENs), is a viable approach to create myostatin-modified goats (Capra hircus).

Results

We obtained a pair of TALENs (MTAL-2) that could recognize and cut the targeted MSTN site in the goat genome. Fibroblasts from pedigreed goats were co-transfected with MTAL-2, and 272 monoclonal cell strains were confirmed to have mono- or bi-allelic mutations in MSTN. Ten cell strains with different genotypes were used as donor cells for somatic cell nuclear transfer, which produced three cloned kids (K179/MSTN^−/−, K52-2/MSTN^+/−, and K52-1/MSTN^+/+).

Conclusions

The results suggested that the MTAL-2 could disrupt MSTN efficiently in the goat genome. The mutated somatic cells could be used to produce MSTN-site mutated goats without developmental disruption. Thus, TALENs is an effective method for accurate genome editing to produce site-modified goats.

Electronic supplementary material

The online version of this article (doi:10.1186/s12861-016-0126-9) contains supplementary material, which is available to authorized users.

A journey through people, places, and projects in equine assisted reproduction

A research study is a product of not only a question and its pursuit but also the people, places, and facilities available at the time. My work in equine assisted reproduction has progressed from embryo transfer to oocyte maturation, oocyte transfer, intracytoplasmic sperm injection, embryo biopsy, embryo vitrification, and cloning, as a result of collaborations with an array of remarkable people. This is a summary of some of the stories behind the studies.

Use of peripheral blood for production of buffalo (Bubalus bubalis) embryos by handmade cloning

Buffalo embryos were produced by handmade cloning using peripheral blood-derived lymphocytes as donor cells. Although the blastocyst rate was lower (P < 0.01) for lymphocyte- than control skin fibroblast-derived embryos (6.6 ± 0.84% vs. 31.15 ± 2.97%), the total cell number (152.6 ± 23.06 vs. 160.1 ± 13.25) and apoptotic index (6.54 ± 0.95 vs. 8.45 ± 1.32) were similar. The global level of H3K9ac was higher (P < 0.05) in lymphocyte- than that in skin-derived blastocysts; whereas in IVF blastocysts, the level was not significantly different from the two cloned groups. The level of H3K27me3 was similar among the three groups. The expression level of DNMT1, DNMT3a, HDAC1, and IGF-1R was higher (P < 0.01) in lymphocytes than that in skin fibroblasts. The expression level of CDX2 was higher (P < 0.05) than that of DNMT3a, IGF-1R, OCT4, and NANOG was lower (P < 0.05) in lymphocyte-derived than in IVF blastocysts; that of DNMT1 and HDAC1 was similar in the two groups. The expression level of all these genes, except that of NANOG, was lower (P < 0.05) in lymphocyte- than in skin fibroblast-derived blastocysts. It is concluded that, peripheral blood-derived lymphocytes can be used for producing handmade cloning embryos in bubaline buffaloes.

Cilostamide and forskolin treatment during pre-IVM improves preimplantation development of cloned embryos by influencing meiotic progression and gap junction communication in pigs

This study was conducted to evaluate the effects of treatment with the cAMP modulators cilostamide and/or forskolin during pre-IVM culture on meiotic progression, gap junction communication, intraoocyte cAMP level and glutathione content, embryonic development after parthenogenesis, and somatic cell nuclear transfer in pigs. Cumulus-oocyte complexes were cultured for 24 hours in unsupplemented medium or media containing 20 μM cilostamide and/or 50 μM forskolin. After pre-IVM, oocytes were cultured for 41 to 44 hours in a standard IVM medium to induce oocyte maturation. When the nuclear status of oocytes was examined after pre-IVM for 24 hours, a higher (P < 0.01) proportion of oocytes treated with forskolin (85.5%) and cilostamide + forskolin (92.6%) remained at the germinal vesicle stage compared with untreated (20.6%) and cilostamide-treated oocytes (54.7%). cAMP level in pre-IVM oocytes was significantly increased by combined treatment with cilostamide + forskolin (21.38 fmol/oocyte) relative to the no pre-IVM control, no treatment, cilostamide, and forskolin groups (2.85, 1.88, 1.74, and 8.95 fmol/oocyte, respectively). Forskolin with or without cilostamide significantly maintained open-gap junction communication relative to no treatment. Blastocyst formation in parthenogenesis was significantly (P < 0.01) improved by forskolin (65.3%) relative to other treatments (28.3% to 48.1%). Supplementation of pre-IVM with dibutyryl cAMP showed similar blastocyst formation as forskolin treatment (61.1% and 61.0%, respectively). In somatic cell nuclear transfer, simultaneous treatment with cilostamide + forskolin significantly (P < 0.05) increased embryonic development to the blastocyst stage (42.9%) relative to the no pre-IVM, control, and cilostamide groups (32.3, 28.6, and 32.8%, respectively). The glutathione contents in pre-IVM oocytes were increased by no treatment, forskolin, and cilostamide + forskolin (1.38, 1.39, and 1.27 pixels/oocyte, respectively) compared with no pre-IVM and cilostamide (1.00 and 0.99 pixels/oocyte, respectively; P < 0.05). Our results reported that the meiotic progression of immature pig oocytes could be reversibly attenuated by cAMP, whereas treatment with cilostamide and forskolin during pre-IVM had positive effects on developmental competence of oocytes in pigs, probably by improving cytoplasmic maturation.

Differential developmental competence and gene expression patterns in buffalo (Bubalus bubalis) nuclear transfer embryos reconstructed with fetal fibroblasts and amnion mesenchymal stem cells

The developmental ability and gene expression pattern at 8- to 16-cell and blastocyst stages of buffalo (Bubalus bubalis) nuclear transfer (NT) embryos from fetal fibroblasts (FFs), amnion mesenchymal stem cells (AMSCs) and in vitro fertilized (IVF) embryos were compared in the present studies. The in vitro expanded buffalo FFs showed a typical "S" shape growth curve with a doubling time of 41.4 h and stained positive for vimentin. The in vitro cultured undifferentiated AMSCs showed a doubling time of 39.5 h and stained positive for alkaline phosphatase, and these cells also showed expression of pluripotency markers (OCT 4, SOX 2, NANOG), and mesenchymal stem cell markers (CD29, CD44) and were negative for haematopoietic marker (CD34) genes at different passages. Further, when AMSCs were exposed to corresponding induction conditions, these cells differentiated into adipogenic, chondrogenic and osteogenic lineages which were confirmed through oil red O, alcian blue and alizarin staining, respectively. Donor cells at 3-4 passage were employed for NT. The cleavage rate was significantly (P < 0.05) higher in IVF than in FF-NT and AMSC-NT embryos (82.6 ± 8.2 vs. 64.6 ± 1.3 and 72.3 ± 2.2 %, respectively). However, blastocyst rates in IVF and AMSC-NT embryos (30.6 ± 2.7 and 28.9 ± 3.1 %) did not differ and were significantly (P < 0.05) higher than FF-NT (19.5 ± 1.8 %). Total cell number did not show significant (P > 0.05) differences between IVF and AMSC-NT embryos (186.7 ± 4.2, 171.2 ± 3.8, respectively) but were significantly (P < 0.05) higher than that from FF-NT (151.3 ± 4.1). Alterations in the expression pattern of genes implicated in transcription and pluripotency (OCT4, STAT3, NANOG), DNA methylation (DNMT1, DNMT3A), histone deacetylation (HDAC2), growth factor signaling and imprinting (IGF2, IGF2R), apoptosis (BAX, BCL2), metabolism (GLUT1) and oxidative stress (MnSOD) regulation were observed in cloned embryos. The transcripts or expression patterns in AMSC-NT embryos more closely followed that of the in vitro derived embryos compared with FF-NT embryos. The results demonstrate that multipotent amnion MSCs have a greater potential as donor cells than FFs in achieving enhanced production of cloned buffalo embryos.

Chromatin condensation of Xist genomic loci during oogenesis in mice

Repression of maternal Xist (Xm-Xist) during preimplantation in mouse embryos is essential for establishing imprinted X chromosome inactivation. Nuclear transplantation (NT) studies using nuclei derived from non-growing (ng) and full-grown (fg) oocytes have indicated that maternal-specific repressive modifications are imposed on Xm-Xist during oogenesis, as well as on autosomal imprinted genes. Recent studies have revealed that histone H3 lysine 9 trimethylation (H3K9me3) enrichments on Xm-Xist promoter regions are involved in silencing at the preimplantation stages. However, whether H3K9me3 is imposed on Xm-Xist during oogenesis is not known. Here, we dissected the chromatin states in ng and fg oocytes and early preimplantation stage embryos. Chromatin immunoprecipitation experiments against H3K9me3 revealed that there was no significant enrichment within the Xm-Xist region during oogenesis. However, NT embryos with ng nuclei (ngNT) showed extensive Xm-Xist derepression and H3K9me3 hypomethylation of the promoter region at the 4-cell stage, which corresponds to the onset of paternal Xist expression. We also found that the chromatin state at the Xist genomic locus became markedly condensed as oocyte growth proceeded. Although the condensed Xm-Xist genomic locus relaxed during early preimplantation phases, the extent of the relaxation across Xm-Xist loci derived from normally developed oocytes was significantly smaller than those of paternal-Xist and ngNT-Xist genomic loci. Furthermore, Xm-Xist from 2-cell metaphase nuclei became derepressed following NT. We propose that chromatin condensation is associated with imprinted Xist repression and that skipping of the condensation step by NT leads to Xist activation during the early preimplantation phase.

Summary: The analysis of chromatin state and H3K9me3 levels in mouse oocytes and early embryos provides insights into the dynamics of Xist repression and activation during early development and reprogramming.

Discovery of porcine maternal factors related to nuclear reprogramming and early embryo development by proteomic analysis

Background

Differentiated cell nuclei can be reprogrammed to a pluripotent state in several ways, including incubation with oocyte extracts, transfer into enucleated oocytes, and induced pluripotent stem cell technology. Nuclear transfer-mediated reprogramming has been proven to be the most efficient method. Maternal factors stored in oocytes have critical roles on nuclear reprogramming and early embryo development, but remain elusive.

Results

In this study, we showed most of porcine oocytes became nuclear matured at 33 h of IVM and the rate had no significant difference with oocytes at 42 h of IVM (p > 0.05). Moreover, the cleavage and blastocyst rates of SCNT and PA embryos derived from 42O were significantly higher than that of 33O (p < 0.05). But 33O could sustain IVF embryo development with higher cleavage and blastocyst rates comparing to 42O (p < 0.05). To clarify the development potential difference between 33O and 42O, 18 differentially expressed proteins were identified by proteomic analysis, and randomly selected proteins were confirmed by Western blot. Bioinformatic analysis of these proteins revealed that 33O highly synthesized proteins related to fertilization, and 42O was rich in nuclear reprogramming factors.

Conclusions

These results present a unique insight into maternal factors related to nuclear reprogramming and early embryo development.

Electronic supplementary material

The online version of this article (doi:10.1186/s12953-015-0074-5) contains supplementary material, which is available to authorized users.

Neonatal Care and Management of Foals Derived by Somatic Cell Nuclear Transfer

There are few reports on the birth of foals resulting from equine adult somatic cell nuclear transfer (NT). On evaluation of reports of 28 live-born adult somatic-cell NT (clone) foals, 3 died within 2 weeks of birth of complications. Approximately 50 % of all reported cloned foals had complications, some requiring aggressive supportive care. The most common abnormalities reported were neonatal maladjustment syndrome, enlarged umbilical remnant, and angular deformity of the forelimbs, similar to problems described in cloned cattle. In contrast, large offspring syndrome and gross abnormalities of the fetal membranes which are described in cloned cattle are not reported in cloned foals. Reports of the health of foals produced by nuclear transfer suggest that NT foals should be treated aggressively as at-risk foals until all parameters are normal.

Procedure used for denuding pig oocytes influences oocyte damage, and development of in vitro and nuclear transfer embryos

The effects of different denuding procedures used during the in vitro culture of porcine embryos on oocyte damage and aspects of porcine embryo development were investigated in a series of studies. Oocytes were denuded by vortexing or pipetting after 44h in vitro maturation (IVM) or pre-denuded after 22h IVM. The total oocyte death rate was significantly (P<0.05) higher for pre-denuded (27.3±1.4%) than for vortexed (20.3±1.2%) or pipetted (16.2±2.2%) oocytes. There was no significant difference between the treatments in the percentage of oocytes that extruded the first polar body. The type I cortical granule distribution (reflecting complete maturity) and normal spindle formation rates were significantly lower in the pre-denuding than in the vortexing and pipetting treatments. Blastocyst formation rates were significantly lower for the pre-denuding treatment in PA (25.7±4.5%) and IVF (6.1±1.5%) culture than in the vortexing (PA 42.0±4.5%; IVF 11.2±0.5%) and pipetting (PA 43.4±3.1%; IVF 9.4±1.6%) treatments. The proportion of oocytes developing to blastocysts in SCNT culture was not significantly different between treatments ranging from 9.9±1.8% for pre-denuding to 12.3±2.7% for vortexing. No significant differences in apoptosis or embryonic fragmentation were observed. This study shows that the denuding procedure used for porcine oocytes during the in vitro production of embryos can significantly affect oocyte damage, spindle patterns, oocyte maturation, embryo development but not embryonic apoptosis or the frequency of fragmentation.

Ultrasonographic fetal parameters and neonatal survival in somatic cell nuclear transfer-derived beef calves

The objectives of this study were to identify prognostic indicators of calf survival in SCNT-derived beef calves. Ultrasonographic parameters of fetal well-being and development, maternal clinical parameters, and neonatal parameters were evaluated as predictors of calf survival in cows carrying SCNT-derived beef fetuses (n = 38). Calf survival was 61.5% (88.2% female and 40.9% male calves; P = 0.0026). Cow respiratory rate and cow temperature were significantly greater in the nonsurviving (NS) group 1 week prepartum. In surviving (S) calves, fetal heart rate (FHR) decreased during the last 2 weeks of gestation (P < 0.01). However, this final deceleration was not observed in NS calves, resulting in higher FHRs in this group (P < 0.0001). Fetal movement and fluid scores did not differ with calf classification. Mean amniotic fluid depth was smaller in S (5.5 ± 0.7 cm) than NS (8.7 ± 1.4 cm) calves (P = 0.0398). However, mean allantoic fluid depth did not differ (P = 0.6120). There was a significant association between the body weight of calf and the diameter of the fetal aorta (P = 0.0115; r(2) = 0.3762). Surviving calves were lighter at birth (P = 0.0028) and were born later (P = 0.007) than NS calves. Calves born vaginally had a smaller fetal aorta (2.1 ± 0.1 cm vaginal and 2.4 ± 0.1 cm Cesarean) (P = 0.0487) and a lighter birth weight (41.4 ± 4.2 kg vaginal and 60.4 ± 2.1 kg Cesarean) (P = 0.0001) than calves born by Cesarean. Also, calves that underwent spontaneous labor (52.2% S and 0% NS; P = 0.0029) had a lighter birth weight (44.9 ± 3.8 kg) than calves that did not initiate labor (61.6 ± 2.2 kg) (P = 0.0004). Frequent ultrasonographic fetal monitoring allowed identification of differences between S and NS calves. Calves without a final decrease in FHR or with a large aortic diameter were more likely to require a Cesarean because of failure to initiate labor or fetomaternal disproportion. Parameters of fetal well-being and development during the last 3 weeks of gestation were first described in SCNT-derived beef calves.

Ovum pick up, intracytoplasmic sperm injection and somatic cell nuclear transfer in cattle, buffalo and horses: from the research laboratory to clinical practice

Assisted reproductive techniques developed for cattle in the last 25 years, like ovum pick up (OPU), intracytoplasmic sperm injection (ICSI), and somatic cell nuclear transfer, have been transferred and adapted to buffalo and horses. The successful clinical applications of these techniques require both the clinical skills specific to each animal species and an experienced laboratory team to support the in vitro phase of the work. In cattle, OPU can be considered a consolidated technology that is rapidly outpacing conventional superovulation for embryo transfer. In buffalo, OPU represents the only possibility for embryo production to advance the implementation of embryo-based biotechnologies in that industry, although it is still mainly in the developmental phase. In the horse, OPU is now an established procedure for breeding from infertile and sporting mares throughout the year. It requires ICSI that in the horse, contrary to what happens in cattle and buffalo, is very efficient and the only option because conventional IVF does not work. Somatic cell nuclear transfer is destined to fill a very small niche for generating animals of extremely high commercial value. The efficiency is low, but because normal animals can be generated it is likely that advancing our knowledge in that field might improve the technology and reduce its cost.

The carp-goldfish nucleocytoplasmic hybrid has mitochondria from the carp as the nuclear donor species

It is widely accepted that mitochondria and its DNA (mtDNA) exhibit strict maternal inheritance, with sperm contributing no or non-detectable mitochondria to the next generation. In fish, nuclear transfer (NT) through the combination of a donor nucleus and an enucleated oocyte can produce fertile nucleocytoplasmic hybrids (NCHs) even between different genera and subfamilies. One of the best studied fish NCHs is CyCa produced by transplanting the nuclei plus cytoplasm from the common carp (Cyprinus carpio var. wuyuanensis) into the oocytes of the wild goldfish (Carassius auratus), which has been propagated by self-mating for three generations. These NCH fish thus provide a unique model to study the origin of mitochondria. Here we report the complete mtDNA sequence of the CyCa hybrid and its parental species carp and goldfish as nuclear donor and cytoplasm host, respectively. Interestingly, the mtDNA of NCH fish CyCa is 99.69% identical to the nuclear donor species carp, and 89.25% identical to the oocyte host species goldfish. Furthermore, an amino acid sequence comparison of 13 mitochondrial proteins reveals that CyCa is 99.68% identical to the carp and 87.68% identical to the goldfish. On an mtDNA-based phylogenetic tree, CyCa is clustered with the carp but separated from the goldfish. A real-time PCR analysis revealed the presence of carp mtDNA but the absence of goldfish mtDNA. These results demonstrate--for the first time to our knowledge--that the mtDNA of a NCH such as CyCa fish may originate from its nuclear donor rather than its oocyte host.

Validation of a recombinant human bactericidal/permeability-increasing protein (hBPI) expression vector using murine mammary gland tumor cells and the early development of hBPI transgenic goat embryos

Human bactericidal/permeability-increasing protein (hBPI) is the only antibacterial peptide which acts against both gram-negative bacteria and neutralizes endotoxins in human polymorphonuclear neutrophils; therefore, hBPI is of great value in clinical applications. In the study, we constructed a hBPI expression vector (pBC1-Loxp-Neo-Loxp-hBPI) containing the full-length hBPI coding sequence which could be specifically expressed in the mammary gland. To validate the function of the vector, in vitro cultured C127 (mouse mammary Carcinoma Cells) were transfected with the vector, and the transgenic cell clones were selected to express hBPI by hormone induction. The mRNA and protein expression of hBPI showed that the constructed vector was effective and suitable for future application in producing mammary gland bioreactor. Then, female and male goat fibroblasts were transfected with the vector, and two male and two female transgenic clonal cell lines were obtained. Using the transgenic cell lines as nuclear donors for somatic cell nuclear transfer, the reconstructed goat embryos produced from all four clones could develop to blastocysts in vitro. In conclusion, we constructed and validated an efficient mammary gland-specific hBPI expression vector, pBC1-Loxp-Neo-Loxp-hBPI, and transgenic hBPI goat embryos were successfully produced, laying foundations for future production of recombinant hBPI in goat mammary gland.

The effect of the number of transferred embryos, the interval between nuclear transfer and embryo transfer, and the transfer pattern on pig cloning efficiency

To improve the efficiency of producing cloned pigs, we investigated the influence of the number of transferred embryos, the culturing interval between nuclear transfer (NT) and embryo transfer, and the transfer pattern (single oviduct or double oviduct) on cloning efficiency. The results demonstrated that transfer of either 150-200 or more than 200NT embryos compared to transfer of 100-150 embryos resulted in a significantly higher pregnancy rate (48 ± 16, 50 ± 16 vs. 29 ± 5%, p<0.05) and average litter size (4.1 ± 2.3, 7 ± 3.6 vs. 2.5 ± 0.5). In vitro culture of reconstructed embryos for a longer time (40 h vs. 20 h) resulted in higher (p<0.05) pregnancy rate (44 ± 9 vs. 31 ± 3%) and delivery rate (44 ± 9 vs. 25 ± 9%). Furthermore, double oviductal transfer dramatically increased pregnancy rate (83 ± 6 vs. 27+8%, p<0.05), delivery rate (75 ± 2 vs. 27+8%, p<0.05) and average litter size (6.5 ± 2.8 vs. 2.6 ± 1.2) compared to single oviductal transfer. Our study demonstrated that an improvement in pig cloning efficiency is achieved by adjusting the number and in vitro culture time of reconstructed embryos as well as the embryo transfer pattern.

Nuclear reprogramming

There is currently particular interest in the field of nuclear reprogramming, a process by which the identity of specialised cells may be changed, typically to an embryonic-like state. Reprogramming procedures provide insight into many mechanisms of fundamental cell biology and have several promising applications, most notably in healthcare through the development of human disease models and patient-specific tissue-replacement therapies. Here, we introduce the field of nuclear reprogramming and briefly discuss six of the procedures by which reprogramming may be experimentally performed: nuclear transfer to eggs or oocytes, cell fusion, extract treatment, direct reprogramming to pluripotency and transdifferentiation.

Nuclear reprogramming of sperm and somatic nuclei in eggs and oocytes

Eggs and oocytes have a prominent ability to reprogram sperm nuclei for ensuring embryonic development. The reprogramming activity that eggs/oocytes intrinsically have towards sperm is utilised to reprogram somatic nuclei injected into eggs/oocytes in nuclear transfer (NT) embryos. NT embryos of various species can give rise to cloned animals, demonstrating that eggs/oocytes can confer totipotency even to somatic nuclei. However, many studies indicate that reprogramming of somatic nuclei is not as efficient as that of sperm nuclei. In this review, we explain how and why sperm and somatic nuclei are differentially reprogrammed in eggs/oocytes. Recent studies have shown that sperm chromatin is epigenetically modified to be adequate for early embryonic development, while somatic nuclei do not have such modifications. Moreover, epigenetic memories encoded in sperm chromatin are transgenerationally inherited, implying unique roles of sperm. We also discuss whether somatic nuclei can be artificially modified to acquire sperm-like chromatin states in order to increase the efficiency of nuclear reprogramming.

Mitochondrial DNA transmission and confounding mitochondrial influences in cloned cattle and pigs

Although somatic cell nuclear transfer (SCNT) is a powerful tool for production of cloned animals, SCNT embryos generally have low developmental competency and many abnormalities. The interaction between the donor nucleus and the enucleated ooplasm plays an important role in early embryonic development, but the underlying mechanisms that negatively impact developmental competency remain unclear. Mitochondria have a broad range of critical functions in cellular energy supply, cell signaling, and programmed cell death; thus, affect embryonic and fetal development. This review focuses on mitochondrial considerations influencing SCNT techniques in farm animals. Donor somatic cell mitochondrial DNA (mtDNA) can be transmitted through what has been considered a "bottleneck" in mitochondrial genetics via the SCNT maternal lineage. This indicates that donor somatic cell mitochondria have a role in the reconstructed cytoplasm. However, foreign somatic cell mitochondria may affect the early development of SCNT embryos. Nuclear-mitochondrial interactions in interspecies/intergeneric SCNT (iSCNT) result in severe problems. A major biological selective pressure exists against survival of exogenous mtDNA in iSCNT. Yet, mtDNA differences in SCNT animals did not reflect transfer of proteomic components following proteomic analysis. Further study of nuclear-cytoplasmic interactions is needed to illuminate key developmental characteristics of SCNT animals associated with mitochondrial biology.