BF170 hydrochloride enhances the emergence of hematopoietic stem and progenitor cells.

Generation of hematopoietic stem and progenitor cells (HSPCs) ex vivo and in vivo, especially the generation of safe therapeutic HSPCs, still remains inefficient. In this study, we have identified compound BF170 hydrochloride as a previously unreported pro-hematopoiesis molecule, using the differentiation assays of primary zebrafish blastomere cell culture and mouse embryoid bodies (EBs), and we demonstrate that BF170 hydrochloride promoted definitive hematopoiesis in vivo. During zebrafish definitive hematopoiesis, BF170 hydrochloride increases blood flow, expands hemogenic endothelium (HE) cells and promotes HSPC emergence. Mechanistically, the primary cilia-Ca2+-Notch/NO signaling pathway, which is downstream of the blood flow, mediated the effects of BF170 hydrochloride on HSPC induction in vivo. Our findings, for the first time, reveal that BF170 hydrochloride is a compound that enhances HSPC induction and may be applied to the ex vivo expansion of HSPCs.

Effect of Triclosan Exposure on Developmental Competence in Parthenogenetic Porcine Embryo during Preimplantation.

Triclosan (TCS) is included in various healthcare products because of its antimicrobial activity; therefore, many humans are exposed to TCS daily. While detrimental effects of TCS exposure have been reported in various species and cell types, the effects of TCS exposure on early embryonic development are largely unknown. The aim of this study was to determine if TCS exerts toxic effects during early embryonic development using porcine parthenogenetic embryos in vitro. Porcine parthenogenetic embryos were cultured in in vitro culture medium with 50 or 100 µM TCS for 6 days. Developmental parameters including cleavage and blastocyst formation rates, developmental kinetics, and the number of blastomeres were assessed. To determine the toxic effects of TCS, apoptosis, oxidative stress, and mitochondrial dysfunction were assessed. TCS exposure resulted in a significant decrease in 2-cell rate and blastocyst formation rate, as well as number of blastomeres, but not in the cleavage rate. TCS also increased the number of apoptotic blastomeres and the production of reactive oxygen species. Finally, TCS treatment resulted in a diffuse distribution of mitochondria and decreased the mitochondrial membrane potential. Our results showed that TCS exposure impaired porcine early embryonic development by inducing DNA damage, oxidative stress, and mitochondrial dysfunction.

Taxol Improves Pre-Implantation Development Potential of Mouse Embryos.

AIM: The objective of the present study was to investigate the development of mouse embryos and the chromosomal status after the pre-implantation treatment with paclitaxel (Taxol) based on the reports that indicate Taxol improves the developmental potential of vitrified human and mouse oocytes. METHODS: Outbred female mice were superovulated and in vitro fertilization (IVF) was carried out using sperms from the same strain. Two-cell stage mouse embryos were cultured in the presence of Taxol for 24 h. After the determination of a non-toxic dose of Taxol, embryo development in control and Taxol-treated groups was compared during 3.5 days post-IVF. The aneuploidy rate of embryos was assessed by fluorescence in situ hybridization for chromosomes 2 and 11. RESULTS: Development to morula and blastocyst stages was considerably enhanced following the addition of Taxol 0.01 µM compared to a similar situation in controls (p < 0.0001). Moreover, the degeneration rate was decreased following treatment with this concentration of Taxol (p < 0.01). The rate of aneuploidy in embryos and individual blastomeres did not vary between groups (p = 0.518 and 0.810 respectively). CONCLUSION: Pre-implantation treatment with Taxol 0.01 µM had a positive effect on the development to morula/blastocyst stages and decreased the degeneration rate without affecting the aneuploidy rate of chromosomes 2 and 11.

Single blastomeres as a source of mouse embryonic stem cells: effect of genetic background, medium supplements, and signaling modulators on derivation efficiency.

PURPOSE: To assess the role of the genetic background, the culture medium supplements, and the presence of modulators of signaling pathways on mouse embryonic stem cell derivation from single blastomeres from 8-cell embryos. METHODS: Mice from permissive and non-permissive genetic backgrounds, different culture media supplements, knockout serum replacement (KSR) and N2B27, and the presence or absence of 2i treatment were used to derive mouse embryonic stem cells (mESC) from single blastomeres isolated from 8-cell embryos and from control embryos at the blastocyst stage. After the sixth passage, the putative mESC were analyzed by immunofluorescence to assess their pluripotency and, after in vitro differentiation induction, their ability to differentiate into derivatives of the three primary germ layers. Selected mESC lines derived from single blastomeres in the most efficient culture conditions were further characterized to validate their stemness. RESULTS: In control embryos, high mESC derivation efficiencies (70-96.9%) were obtained from permissive backgrounds or when embryos were cultured in medium complemented with 2i regardless of their genetic background. By contrast, only blastomeres isolated from embryos from permissive background cultured in KSR-containing medium complemented with 2i were moderately successful in the derivation of mESC lines (22.9-24.5%). Moreover, we report for the first time that B6CBAF2 embryos behave as permissive in terms of mESC derivation. CONCLUSIONS: Single blastomeres have higher requirements than whole blastocysts for pluripotency maintenance and mESC derivation. The need for 2i suggests that modulation of signaling pathways to recreate a commitment towards inner cell mass could be essential to efficiently derive mESC from single blastomeres.

Resveratrol enhances the clearance of mitochondrial damage by vitrification and improves the development of vitrified-warmed bovine embryos.

The present study investigated the vitrification-induced deterioration of mitochondrial functions that may reduce the developmental ability of post-warming bovine embryos. In addition, the effect of supplementation of the culture medium with resveratrol on the mitochondrial functions and post-warming embryonic development was examined. Two days after in vitro fertilization, embryos with 8-12 cells (referred to hereafter as 8-cell embryos) were vitrified and warmed, followed by in vitro incubation for 5 days in a culture medium containing either the vehicle or 0.5 µM resveratrol. Vitrification reduced embryonic development until the blastocyst stage, reduced the ATP content of embryos, and impaired the mitochondrial genome integrity, as determined by real-time polymerase chain reaction. Although the total cell number and mitochondrial DNA copy number (Mt-number) of blastocysts were low in the vitrified embryos, the Mt-number per blastomere was similar among the blastocysts derived from fresh (non-vitrified) and vitrified-warmed embryos. Supplementation of the culture medium with resveratrol enhanced the post-warming embryonic development and reduced the Mt-number and reactive oxygen species level in blastocysts and blastomeres without affecting the ATP content. An increase in the content of cell-free mitochondrial DNA in the spent culture medium was observed following cultivation of embryos with resveratrol. These results suggested that vitrification induces mitochondrial damages and that resveratrol may enhance the development of post-warming embryos and activates the degeneration of damaged mitochondria, as indicated by the increase in the cell-free mitochondrial DNA content in the spent culture medium and the decrease in the Mt-number of blastocysts and blastomeres.

Dedifferentiation into blastomere-like cancer stem cells via formation of polyploid giant cancer cells.

Our recent perplexing findings that polyploid giant cancer cells (PGCCs) acquired embryonic-like stemness and were capable of tumor initiation raised two important unanswered questions: how do PGCCs acquire such stemness, and to which stage of normal development do PGCCs correspond. Intriguingly, formation of giant cells due to failed mitosis/cytokinesis is common in the blastomere stage of the preimplantation embryo. However, the relationship between PGCCs and giant blastomeres has never been studied. Here, we tracked the fate of single PGCCs following paclitaxel-induced mitotic failure. Morphologically, early spheroids derived from PGCCs were indistinguishable from human embryos at the blastomere, polyploid blastomere, compaction, morula and blastocyst-like stages by light, scanning electron or three-dimensional confocal scanning microscopy. Formation of PGCCs was associated with activation of senescence, while budding of daughter cells was associated with senescence escape. PGCCs showed time- and space-dependent activation of expression of the embryonic stem cell markers OCT4, NANOG, SOX2 and SSEA1 and lacked expression of Xist. PGCCs acquired mesenchymal phenotype and were capable of differentiation into all three germ layers in vitro. The embryonic-like stemness of PGCCs was associated with nuclear accumulation of YAP, a key mediator of the Hippo pathway. Spheroids derived from single PGCCs grew into a wide spectrum of human neoplasms, including germ cell tumors, high-grade and low-grade carcinomas and benign tissues. Daughter cells derived from PGCCs showed attenuated capacity for invasion and increased resistance to paclitaxel. We also observed formation of PGCCs and dedifferentiation in ovarian cancer specimens from patients treated with chemotherapy. Taken together, our findings demonstrate that PGCCs represent somatic equivalents of blastomeres, the most primitive cancer stem cells reported to date. Thus, our studies reveal an evolutionarily conserved archaic embryonic program in somatic cells that can be de-repressed for oncogenesis. Our work offers a new paradigm for cancer origin and disease relapse.

Recombinant fetuin-B protein maintains high fertilization rate in cumulus cell-free mouse oocytes.

STUDY QUESTION: Does fetuin-B inhibit premature zona pellucida (ZP) hardening in mouse oocytes in vitro and thus increase IVF rate? SUMMARY ANSWER: Supplementation of oocyte in vitro maturation (IVM) media with recombinant mouse fetuin-B (rmFetuB) increased fertilization rate without affecting mouse embryo development into blastocysts. WHAT IS KNOWN ALREADY: Mice deficient in fetuin-B are infertile owing to premature ZP hardening. Premature ZP hardening also occurs during oocyte IVM leading to decreased fertilization rate. STUDY DESIGN, SIZE, DURATION: We fertilized batches of 20-30 mouse metaphase II (Mll) stage oocytes from C57BL/6 mice with fresh sperm, and studied early embryo development until blastocyst hatching. PARTICIPANTS/MATERIALS, SETTING, METHODS: Oocytes were maintained with or without rmFetuB during IVM and IVF. Exogenous rmFetuB was added to media prior to oocyte isolation. ZP hardening was quantified by chymotrypsin digestion timing and by counting attached sperm. MAIN RESULTS AND THE ROLE OF CHANCE: In the absence of cumulus cells, rmFetuB dose-dependently inhibited ZP hardening and increased IVF rate (P = 0.039). Fetuin-B at ≥0.03 mg/ml also inhibited physiological, fertilization-triggered ZP hardening (indicated by increased sperm binding, P = 0.0002), without increasing embryo death. Exogenous rmFetuB increased IVF rate for up to 5 hours of IVM (P = 0.02 at 1 hour, P = 0.01 at 5 hours of IVM). LIMITATIONS, REASONS FOR CAUTION: Mll stage oocytes in this study were isolated from the ampullae of fetuin-B expressing mice. Thus, oocytes were protected against premature ZP hardening by endogenous fetuin-B. In humans and livestock, oocytes are usually isolated by follicle puncture before ovulation. In this situation, the deprivation of endogenous fetuin-B would occur earlier and the effect of exogenous fetuin-B in the IVF medium may be even more pronounced. Fertilization-triggered ZP hardening is essential for embryo development but in this study the effect of fetuin-B supplementation was only studied to blastocyst stage. Any influence of added fetuin-B on later embryo development after transplantation remains to be determined. WIDER IMPLICATIONS OF THE FINDINGS: The astacin-type protease ovastacin triggers definitive ZP hardening by cleaving the zona pellucida protein 2. Animal sera are known to inhibit premature ZP hardening. The addition of rFetuB to the culture medium of oocytes could increase IVF rates by the inhibition of premature ZP hardening. In this regard, the results could be useful for clinical activity. LARGE SCALE DATA: None. STUDY FUNDING/COMPETING INTERESTS: The research was supported by a grant from Deutsche Forschungsgemeinschaft and by the START program of the Medical Faculty of RWTH Aachen University. The authors ED, JF and WJD are named inventors on a patent application of RWTH Aachen University covering the use of fetuin-B in ovary and oocyte culture.

T-2 mycotoxin slows down the development of mouse blastocysts, decreases their blastomere number and increases chromatin damage.

The mycotoxin T-2 has many harmful effects on mammalian cells and reproductive functions. In the present study, the in vitro effect of T-2 toxin on mouse blastocysts was examined. Embryos were cultured in media supplemented with 0.5, 0.75 and 1 ng/ml T-2. Different exposure times were applied [96 h (treatment I) or 24 h following 72 h in toxin-free media (treatment II)]. Blastomere number, nuclear chromatin status and blastocoel formation were investigated in blastocysts. Our data show that the effect of T-2 toxin may vary depending on the stage of the embryo at the start of exposure. At 96 h of exposure, the blastocysts had blastomeres with normal chromatin quality but their developmental potential was decreased. After 24 h of exposure applied following a 72-h culture, blastomeres had a higher level of chromatin damage, although their developmental potential was the same as in the control embryos. In both cases, decreased mitotic rate was found, which resulted in decreased blastomere number even at low toxin concentration.

Inhibition of Rho­associated protein kinase increases the ratio of formation of blastocysts from single human blastomeres.

Y­27632 is a specific inhibitor of Rho­associated protein kinases (ROCKs), which are downstream effectors of Rho GTPase. The present study aimed to determine the effect of the specific ROCK inhibitor, Y­27632, on fresh human embryos and on single blastomeres obtained from discarded human embryos. A total of 784 poor­quality embryos were included, of which 526 were allocated to blastocyst culture directly and the remaining 258 were allocated to blastomere isolation. Embryos and single blastomeres were cultured either with, or without, Y­27632. Embryonic development was observed and recorded daily from day 5 onwards. Y­27632 did not affect the ratio of blastocyst formation or the quality of the human embryos. The duration of blastocyst formation was compared between the two groups in the embryo culture. On day 5, the blastocyst formation ratio in the experimental group was 11.4% (26/228), which was significantly (P=0.015) lower than the corresponding rate (19.7%; 44/223) in the control group. Survival analysis of the blastocyst formation duration showed that the median formation duration in the experimental group was significantly higher than that of the control group. The present study also obtained 1,192 blastomeres from 258 discarded day 3 embryos, and sibling blastomeres of similar sizes were equally allocated to experimental and control groups (n=596 in each). Treatment with Y­27632 increased the blastocyst formation ratio of human individual blastomeres, with 82 blastocysts of 596 blastomeres (13.8%), and 51 blastocysts of 596 blastomeres (8.6%) formed in the presence and absence of Y­27632, respectively (P=0.004). Compared with the control group, the mRNA and protein expression levels of E­cadherin in the blastocysts from blastomeres were enhanced by Y­27632 (P=0.022). In conclusion, the present study demonstrated that Y­27632 has different effects on the cleavage­stage of embryos and single blastomeres. Y­27632 increases the ratio of formation of blastocysts from single human blastomeres, but inhibits the direct formation of blastocysts from discarded human embryos.

System for evaluation of oxidative stress on in-vitro-produced bovine embryos.

This study proposed a quantitative evaluation of oxidative status (OS) in bovine embryos. Sixteen-cell stage embryos, cultured under 5% O2, were treated with oxidative stress inducer menadione (0, 1, 2.5 and 5 µmol/l) for 24 h. Blastocyst rate (BLR) was recorded and expanded blastocysts were stained with CellROX®Green (CRG; OS evaluation) and evaluated under epifluorescence microscopy (ratio of pixel/blastomere). A significant effect of menadione was observed for BLR (P = 0.0039), number of blastomeres/embryo (P < 0.0001) and OS (P < 0.001). Strong negative correlations were found between BLR and the number of blastomeres with OS evaluation, demonstrating the efficacy of this analysis to evaluate OS levels of IVF bovine embryos.

Tyrosine glycosylation of Rho by Yersinia toxin impairs blastomere cell behaviour in zebrafish embryos.

Yersinia species cause zoonotic infections, including enterocolitis and plague. Here we studied Yersinia ruckeri antifeeding prophage 18 (Afp18), the toxin component of the phage tail-derived protein translocation system Afp, which causes enteric redmouth disease in salmonid fish species. Here we show that microinjection of the glycosyltransferase domain Afp18(G) into zebrafish embryos blocks cytokinesis, actin-dependent motility and cell blebbing, eventually abrogating gastrulation. In zebrafish ZF4 cells, Afp18(G) depolymerizes actin stress fibres by mono-O-GlcNAcylation of RhoA at tyrosine-34; thereby Afp18(G) inhibits RhoA activation by guanine nucleotide exchange factors, and blocks RhoA, but not Rac and Cdc42 downstream signalling. The crystal structure of tyrosine-GlcNAcylated RhoA reveals an open conformation of the effector loop distinct from recently described structures of GDP- or GTP-bound RhoA. Unravelling of the molecular mechanism of the toxin component Afp18 as glycosyltransferase opens new perspectives in studies of phage tail-derived protein translocation systems, which are preserved from archaea to human pathogenic prokaryotes.

Tauroursodeoxycholic acid improves the implantation and live-birth rates of mouse embryos.

We previously demonstrated that tauroursodeoxycholic acid (TUDCA) improved the developmental competence of mouse embryos by attenuating endoplasmic reticulum (ER) stress-induced apoptosis during preimplantation development. Here, we present a follow-up study examining whether TUDCA enhances the implantation and live-birth rate of mouse embryos. Mouse 2-cell embryos were collected by oviduct flushing and cultured in the presence or absence of 50 µM TUDCA. After culture (52 h), blastocysts were transferred to 2.5-day pseudopregnant foster mothers. It was found that the rates of pregnancy and implantation as well as the number of live pups per surrogate mouse were significantly higher in the TUDCA-treated group compared to the control group, but there was no significant difference in the mean weights of the pups or placentae. Thus, we report for the first time that TUDCA supplementation of the embryo culture medium increased the implantation and livebirth rates of transferred mouse embryos.

Embryonic early-cleavage rate is decreased with aging in GnRH agonist but not inantagonist protocols.

PURPOSE: The aim of this study was to evaluate the correlation between embryonic early-cleavage status and the age of patients receiving either a GnRH agonist long protocol or a GnRH antagonist protocol. METHODS: This retrospective study included 534 patients undergoing a fresh cycle of oocyte retrieval and day-3 embryo transfer. Of the 534 patients treated, 331 received a GnRH agonist long stimulation protocol (GnRH agonist group) for ovarian stimulation and 203 patients received a GnRH antagonist protocol (GnRH antagonist group). RESULTS: By logistic regression analysis, the rate of embryonic early-cleavage was significantly decreased with increasing age of women in the agonist (P < 0.001) but not in antagonist groups (P = 0.61). Based on the results of this study, maternal age is a critical factor for embryonic early-cleavage in agonist protocol but not in antagonist protocol. The results also showed that early-cleavage embryos were of better quality and resulted in a higher pregnancy rate than late-cleavage embryos in the GnRH agonist group. However, embryo quality and pregnancy rate was not significantly different between early and late cleavage embryos in the GnRH antagonist group. CONCLUSIONS: We conclude that embryonic early-cleavage status is negatively correlated with aging in women receiving GnRH agonist long down-regulation but not in GnRH antagonist protocols. We also conclude that early cleavage of the zygote is not a reliable predictor for pregnancy potential using the GnRH antagonist protocol.

Pre-implantation developmental potential from in vivo and in vitro matured mouse oocytes: a cytoskeletal perspective on oocyte quality.

PURPOSE: In the present study, fertilization and developmental potential of mouse oocytes matured in different conditions were tested. The efficiency of in vitro fertilization (IVF), pre-implantation development and some important aspects of cytokinesis during early cleavages are discussed. METHODS: In vivo matured (IVO), in vitro matured (IVM) and roscovitine-treated (IVM-Rosco) mouse oocytes were subjected to IVF under identical conditions. Three replicates per group were analyzed. Fertilization was identified by the presence of two pronuclei at 6-8 h post-fertilization. Evaluation of pre-implantation embryonic development was done daily from day 2 to day 5 and embryos were processed for analyses of chromatin, nuclear lamina, microtubules and centrosomal proteins by conventional and confocal fluorescence microscopy. RESULTS: Both IVM groups displayed lower fertilization rates when compared to in vivo controls. While IVO-derived embryos exhibit efficient and synchronous progression to the blastocyst stage, both IVM-derived embryos exhibit a delay in embryonic progression, and a lower blastocyst rate. Interestingly, IVM-Rosco M-II oocytes exhibited more blastomere symmetries and higher number of cells at the blastocyst stage than the IVM group with the most notable influence being on the centrosome-microtubule complex of blastomeres. CONCLUSION: Our study strongly indicates that when compared to spontaneously in vitro matured oocytes, treatment with roscovitine may partially enhance developmental competence by maintaining coordination between nuclear and cytoplasmic events. Further evidence is given of cytoskeletal biomarkers that can be identified during in vitro oocyte maturation conditions.

Benzo(a)pyrene disrupts mouse preimplantation embryo development.

OBJECTIVE: To determine the effects of Benzo(a)pyrene (BaP) on the development of early preimplantation embryo by exposure to physiologic concentrations of BaP based on a previous report in human ovarian follicular fluid and serum. DESIGN: Zygotes were cultured in 5 nM or 50 nM BaP and then examined for development efficiency, embryo quality, and DNA damage. In addition, embryonic stem cells (ESCs) were used as a model to test the toxic effects of BaP on inner cell mass (ICM) of blastocysts. SETTING: Laboratory. ANIMAL(S): CD1 mice. INTERVENTION(S): Mouse zygotes and ESCs were cultured in medium with 5 nM or 50 nM BaP. MAIN OUTCOME MEASURE(S): The percentage (rate) of blastocyst development, reactive oxygen species level, and quality of embryos assessed by total cell number, cell apoptosis, Oct4- and Nanog-positive cell ratio, and DNA damage on genomic and telomeric DNA were compared between dimethyl sulfoxide control and BaP treatments. RESULT(S): The BaP-treated zygotes exhibited significantly higher reactive oxygen species activity, which might lead to more cell apoptosis, low ratio of Nanog- or Oct4-positive ICM cells, and increasing DNA damage in both genomic and telomeric DNA in blastocysts. By using mouse ESCs derived from ICM cells as a model, we showed that pluripotent cells might also show serious DNA damage after a brief exposure to BaP. CONCLUSION(S): Our data show that BaP could seriously disrupt cell growth and genomic DNA stability and increase cell apoptosis in mouse preimplantation embryo development.

Natrium fluoride influences methylation modifications and induces apoptosis in mouse early embryos.

This study epigenetically examined the effect of fluoride on early embryos of Kunming mice administered with 0, 20 (low), 60 (medium), and 120 mg/L (high) sodium fluoride (NaF). The results showed that NaF repressed oocyte maturation, fertilization and blastocyst formation in all NaF-treated groups. Meanwhile, TUNEL assay showed that embryo apoptosis was induced dramatically in blastocyst stage at either low or medium doses, and in 8-cell stage at high dose, compared to the control, suggesting a dose-dependent effect. Furthermore, the immunostaining displayed global increases of DNA methylation, H3K9m2 and H3K4m2 with increasing dose, which were consistent with gene expression results, exhibiting general increases of DNMT1, DNMT3a, G9a, LSD1, and MLL1 and a reduction of JHDM2a in transcription and protein levels. More closely, the differential methylation domain in parentally imprinted gene H19 showed low methylation, while materanlly imprinted gene IGF2 showed high methylaiton in NaF-treated groups compared to the control group, which corresponded with high expression of H19 and low expression of IGF2 confirmed by qPCR. Collectively, we demonstrated that fluoride epigenetically impaired mouse oocyte maturation and embryonic development, supplying a better knowledge of fluoride in toxicology and a deeper evaluation of its potential influence in physiological and clinical implications.

Evidence supporting a functional requirement of SMAD4 for bovine preimplantation embryonic development: a potential link to embryotrophic actions of follistatin.

Transforming growth factor beta (TGFbeta) superfamily signaling controls various aspects of female fertility. However, the functional roles of the TGFbeta-superfamily cognate signal transduction pathway components (e.g., SMAD2/3, SMAD4, SMAD1/5/8) in early embryonic development are not completely understood. We have previously demonstrated pronounced embryotrophic actions of the TGFbeta superfamily member-binding protein, follistatin, on oocyte competence in cattle. Given that SMAD4 is a common SMAD required for both SMAD2/3- and SMAD1/5/8-signaling pathways, the objectives of the present studies were to determine the temporal expression and functional role of SMAD4 in bovine early embryogenesis and whether embryotrophic actions of follistatin are SMAD4 dependent. SMAD4 mRNA is increased in bovine oocytes during meiotic maturation, is maximal in 2-cell stage embryos, remains elevated through the 8-cell stage, and is decreased and remains low through the blastocyst stage. Ablation of SMAD4 via small interfering RNA microinjection of zygotes reduced proportions of embryos cleaving early and development to the 8- to 16-cell and blastocyst stages. Stimulatory effects of follistatin on early cleavage, but not on development to 8- to 16-cell and blastocyst stages, were observed in SMAD4-depleted embryos. Therefore, results suggest SMAD4 is obligatory for early embryonic development in cattle, and embryotrophic actions of follistatin on development to 8- to 16-cell and blastocyst stages are SMAD4 dependent.

Suppression of transforming growth factor ß signaling promotes ground state pluripotency from single blastomeres.

STUDY QUESTION: Can transforming growth factor ß (TGFß) inhibition promote ground state pluripotency of embryonic stem cells (ESCs) from single blastomeres (SBs) of cleavage embryos in different mouse stains? SUMMARY ANSWER: Small molecule suppression of extracellular signal-regulated protein kinases 1 and 2 (ERK1/2) and TGFß signaling (designated as R2i) can enhance the generation of mouse ESCs from SBs of different cleavage stage embryos compared with the dual suppression of ERK1/2 and glycogen synthase kinase 3 (GSK3), designated as 2i, regardless of the strain of mouce. WHAT IS KNOWN ALREADY: It is known that chemical inhibition of TGFß promotes ground state pluripotency in the generation and sustenance of naïve ES cells from mouse blastocysts compared with the well-known 2i condition. However, the positive effect of this inhibition on mouse ESCs from early embryonic SBs remains obscure. STUDY DESIGN, SIZE, DURATION: We used 155 cleavage-stage mouse embryos to optimize the culture conditions for blastocyst development. Then, to assess the effects of R2i and 2i on ESC generation from SBs, we cultured isolated SBs in 2i and R2i for 10 days. SBs were replated under the same conditions to produce ESCs. In total, 46 embryos and 321 SBs from two- to eight-cell stages were recovered from NMRI and BALB/c mouse strains and used in this study. PARTICIPANTS/MATERIALS, SETTING, METHODS: Blastomeres from 2- to 8-cell stage mouse embryos were dispersed and individually seeded into a 96-well plates that included mitotically inactivated feeder cells. ESCs were generated in B27N2 defined medium supplemented with R2i or 2i. Randomly selected ESC lines, generated from SBs of each stage, were assessed for pluripotency and germ-line transmission. MAIN RESULTS AND THE ROLE OF CHANCE: We demonstrated that dual inhibition of ERK1/2 and TGFß (R2i) enhanced efficient blastocyst development and efficient establishment of ESCs from SB of 2- to 8-cell stage mouse embryos compared with the dual inhibition of ERK1/2 and GSK3 (2i) regardless of the embryonic stage and strain of mice. The proportions of SBs that produced ESC were 50-60 versus 20-30%. LIMITATIONS, REASONS FOR CAUTION: This study was done with mouse embryos, it is not known whether these findings are transferable to humans. WIDER IMPLICATIONS OF THE FINDINGS: These findings resulted in an increased efficiency of ESC generation from one biopsied blastomere for autogeneic or allogeneic matched pluripotent cells without the need to destroy viable embryos. The results also provided information about the developmental capacity of early embryonic blastomeres. STUDY FUNDING/COMPETING INTERESTS: This study was funded by grants provided from Royan Institute, the Iranian Council of Stem Cell Research and Technology and the Iran National Science Foundation. The authors have no conflict of interest to declare.

Cyclosporine A improves adhesion and invasion of mouse preimplantation embryos via upregulating integrin ß3 and matrix metalloproteinase-9.

Our previous study has demonstrated cyclosporin A (CsA) promotes the migration and invasiveness of human first-trimester trophoblast cells in vitro. Here, we further investigated the effect of CsA on the early implantation in vitro of mouse embryo. Female C57 mice were superovulated and mated, and then two-cell embryos were harvested from the oviducts and sequentially cultured in vitro in G1 and G2 media with 0, 0.1, 1.0 or 10 µM of CsA. Blastocyte formation, blastocyte cell number and apoptosis, embryo hatching were assessed in 4-6 dpc. The adhesion and stretching growth of hatched embryos in laminin coated dishes were evaluated from 5 dpc to 8 dpc, and the expressions of implantation serine proteinase 1 (ISP1), integrin (itg) ß3 and matrix metalloproteinase (MMP)-9 were determined by real time PCR and immunofluorescence, respectively. We showed there was no significant difference in blastocyst formation rates, hatching rates, number of whole embryonic cells, apoptotic cells, and distribution of inner cell masses (ICMs) and trophoblasts (TB) between the CsA- and control-treated groups. Expression of ISP1 mRNA was unaffected on 5 dpc. After hatching, adhesion rate of 7 dpc significantly increased in 0.1 and 1.0 µM of CsA treatment, and embryo area of 8 dpc stretch growing on laminin were increased in 1.0 µM of CsA. The mRNA and protein expression of itgß3 and MMP-9 on 7 dpc blastocyst were up-regulated. In conclusion, CsA in low dosage up-regulates itgß3 and MMP-9 expression, and enhances embryonic adhesion and invasion, which is beneficial to the embryo implantation.

Treating cloned embryos, but not donor cells, with 5-aza-2'-deoxycytidine enhances the developmental competence of porcine cloned embryos.

The efficiency of cloning by somatic cell nuclear transfer (SCNT) has remained low. In most cloned embryos, epigenetic reprogramming is incomplete, and usually the genome is hypermethylated. The DNA methylation inhibitor 5-aza-2'-deoxycytidine (5-aza-dC) could improve the developmental competence of cow, pig, cat and human SCNT embryos in previous studies. However, the parameters of 5-aza-dC treatment among species are different, and whether 5-aza-dC could enhance the developmental competence of porcine cloned embryos has still not been well studied. Therefore, in this study, we treated porcine fetal fibroblasts (PFF) that then were used as donor nuclei for nuclear transfer or fibroblast-derived reconstructed embryos with 5-aza-dC, and the concentration- and time-dependent effects of 5-aza-dC on porcine cloned embryos were investigated by assessing pseudo-pronucleus formation, developmental potential and pluripotent gene expression of these reconstructed embryos. Our results showed that 5-aza-dC significantly reduced the DNA methylation level in PFF (0 nM vs. 10 nM vs. 25 nM vs. 50 nM, 58.70% vs. 37.37% vs. 45.43% vs. 39.53%, P<0.05), but did not improve the blastocyst rate of cloned embryos derived from these cells. Treating cloned embryos with 25 nM 5-aza-dC for 24 h significantly enhanced the blastocyst rate compared with that of the untreated group. Furthermore, treating cloned embryos, but not donor cells, significantly promoted pseudo-pronucleus formation at 4 h post activation (51% for cloned embryos treated, 34% for donor cells treated and 36% for control, respectively, P<0.05) and enhanced the expression levels of pluripotent genes (Oct4, Nanog and Sox2) up to those of in vitro fertilized embryos during embryo development. In conclusion, treating cloned embryos, but not donor cells, with 5-aza-dC enhanced the developmental competence of porcine cloned embryos by promotion of pseudo-pronucleus formation and improvement of pluripotent gene expression.