Sonic Hedgehog improves in vitro development of porcine parthenotes and handmade cloned embryos

Anethole improves the developmental competence of porcine embryos by reducing oxidative stress via the sonic hedgehog signaling pathway

BACKGROUND

Anethole (AN) is an organic antioxidant compound with a benzene ring and is expected to have a positive impact on early embryogenesis in mammals. However, no study has examined the effect of AN on porcine embryonic development. Therefore, we investigated the effect of AN on the development of porcine embryos and the underlying mechanism.

RESULTS

We cultured porcine in vitro-fertilized embryos in medium with AN (0, 0.3, 0.5, and 1 mg/mL) for 6 d. AN at 0.5 mg/mL significantly increased the blastocyst formation rate, trophectoderm cell number, and cellular survival rate compared to the control. AN-supplemented embryos exhibited significantly lower reactive oxygen species levels and higher glutathione levels than the control. Moreover, AN significantly improved the quantity of mitochondria and mitochondrial membrane potential, and increased the lipid droplet, fatty acid, and ATP levels. Interestingly, the levels of proteins and genes related to the sonic hedgehog (SHH) signaling pathway were significantly increased by AN.

CONCLUSIONS

These results revealed that AN improved the developmental competence of porcine preimplantation embryos by activating SHH signaling against oxidative stress and could be used for large-scale production of high-quality porcine embryos.

Optimal Stage for Cryotop Vitrification of Porcine Embryos

Different development stages of porcine embryos have different tolerance to low temperature. Therefore, we took the porcine embryos after parthenogenetic activation (PA) as the model, to explore the optimal development stage for vitrification during morula (D4), early blastocyst (D5), and expanded blastocyst (D6) after PA (D0). Embryos were observed with microscope and analyzed by different staining after cryo-recovery for 24 hours. The quality of embryos was damaged after vitrification, including embryonic nuclei, DNA, cytoskeleton, and organelles. The re-expansion rate at 24 hours of D5 embryos was significantly higher than those of D4 and D6 embryos (D5 vs. D4 vs. D6, 27.620 ± 0.041 vs. 7.809 ± 0.027 vs. 13.970 ± 0.032, p < 0.05). Therefore, D5 embryos were selected as research objects to explore the effect of vitrification on lipid in vitrified embryos. The results showed that the expression levels of perilipin PLIN3 messenger RNA (mRNA) and triacylglycerol synthesis-related genes AGPAT1 and DGAT mRNA are significantly reduced (p < 0.05). Vitrification affected lipid synthesis, which might have an irreversible impact on embryonic development. In conclusion, our data demonstrated that the optimal stage of vitrification was D5 for early blastocysts.

Baicalin improves the in vitro developmental capacity of pig embryos by inhibiting apoptosis, regulating mitochondrial activity and activating sonic hedgehog signaling

Baicalin, a traditional Chinese medicinal monomer whose chemical structure is known, can be used to treat female infertility. However, the effect of baicalin on embryonic development is unknown. This study investigated the effects of baicalin on in vitro development of parthenogenetically activated (PA) and in vitro fertilized (IVF) pig embryos and the underlying mechanisms involved. Treatment with 0.1 μg/ml baicalin significantly improved (P < 0.05) the in vitro developmental capacity of PA pig embryos by reducing the reactive oxygen species (ROS) levels and apoptosis and increasing the mitochondrial membrane potential (ΔΨm) and ATP level. mRNA and protein expression of sonic hedgehog (SHH) and GLI1, which are related to the SHH signaling pathway, in PA pig embryos at the 2-cell stage, were significantly higher in the baicalin-treated group than in the control group. To confirm that the SHH signaling pathway is involved in the mechanism by which baicalin improves embryonic development, we treated embryos with baicalin in the absence or presence of cyclopamine (Cy), an inhibitor of this pathway. Cy abolished the effects of baicalin on in vitro embryonic development. In conclusion, baicalin improves the in vitro developmental capacity of PA and IVF pig embryos by inhibiting ROS production and apoptosis, regulating mitochondrial activity and activating SHH signaling.

Effect of TET inhibitor on bovine parthenogenetic embryo development

DNA demethylation catalysed by the ten-eleven translocation (TET) protein is an important step during extensive global epigenetic reprogramming in mammals. However, whether TET proteins play a key role in DNA demethylation during the development of bovine pre-implanted embryos is still unclear. In this study, we utilized dimethyloxallyl glycine (DMOG), a small-molecule inhibitor of the TET protein, to impede the enzymatic activity of TET and explore subsequent effects on bovine parthenogenetic embryo development. We first detected the expression of the TET family, consisting of TET1, TET2 and TET3, in bovine MII stage oocytes and found that TET3 is more highly expressed than TET1 and TET2. Treatment with 1 mM DMOG increased 5mC levels (30.4% vs 79.8% at the 8-cell stage for satellite I, 25.3% vs 40.6% at the 8-cell stage for α-satellite, 20.5% vs 73.5% at the blastocyst stage for satellite I and 16.6% vs 30.0% at the blastocyst stage for α-satellite) at every bovine parthenogenetic embryo developmental stage. At the same time, DNA methylation level of satellite DNA and pluripotency gene promoters increased significantly. Real-time PCR analysis results indicated that the transcription levels of NANOG and OCT-4 decreased in the DMOG-treated group. Furthermore, TET inhibition negatively affected blastocyst formation, resulting in a decline in the blastocyst rate (17.1 ± 1.3% vs 24.1 ± 0.6%); however, the percentage of apoptotic cells was significantly increased according to the results of a TUNEL assay. Additionally, expression levels of the apoptosis-related gene BAX were up-regulated, while the expression of BCL-2 was down-regulated. In conclusion, these results support that TET plays important roles in bovine parthenogenetic embryo development by influencing DNA methylation reprogramming, gene expression and apoptosis.

A whole genome sequence association study for puberty in a large Duroc × Erhualian F2 population

A large proportion of gilts and sows are culled from reproduction populations because of anestrus and pubertal reproductive failure. Selecting early onset of puberty gilts has a favorable effect on sows' reproductivity. However, age at puberty is hard to be routinely measured in commercial herds. With molecular genetic predictors, identifying individuals that have a propensity for early onset of puberty can be simplified. We previously performed genome scanning and a genome-wide association study for puberty in an F2 resource population using 183 microsatellites and 62 125 SNPs respectively. The detection power and resolution of identified quantitative trait loci were very low. Herein, we re-sequenced 19 founders of the F2 resource population in high coverage, and whole genome sequences of F2 individuals were imputed to perform an association study for reproductive traits. A total of 2339 SNPs associated with pubertal reproductive failure were identified in the region of 30.94-40.74 Mb on SSC7, with the top one, positioned at 33.36 Mb, explaining 16% of the phenotypic variances. We improved the magnitude of the P-value by 10E+5 to 10E+7 using the whole genome sequence rather than using low/middle density markers as in previous studies, and we narrowed down the QTL confidence interval to 5.25 Mb. Combining the annotation of gene function, RAB23 and BAK1 were perceived as the most compelling candidate genes. The identified loci may be useful in culling sows failing to show estrus by marker-assisted selection to increase reproductive efficiency of swine herds.

Effect of purmorphamine on the mRNA expression of Sonic Hedgehog signaling downstream molecules in ovine embryo

Abstract. Sonic Hedgehog (SHH) is a signaling pathway mediated through a receptor system which seems to have effects on oocyte maturation and embryonic development. Purmorphamine is an SHH agonist that performs a crucial role in the regulation of the activity of SHH receptors and downstream transcription factors. The aim of this study was to analyze the effect of purmorphamine on the mRNA expression of SHH signaling downstream molecules (Patched1, Glioma-Associated Oncogene1, Smoothened, Histone Deacetylase1, Histone Deacetylase2 and Histone Deacetylase3) in ovine two-cell embryo. Ovaries were obtained from a slaughterhouse, and cumulus–oocyte complexes were aspirated and cultured in maturation media containing 0, 250 or 500 ng mL−1 purmorphamine. Then, oocytes were fertilized and cultured in a CR1 culture medium and after 24 h, two-cell embryos were collected for RNA extraction. Gene expression was evaluated by real-time polymerase chain reaction (PCR). Results indicated that in 250 ng mL−1 purmorphamine, Smo, Ptch1 and Hdac3 expression reduced, Hdac1 expression increased, and Gli1 and Hdac2 expression levels did not change. In 500 ng mL−1 purmorphamine, Gli1 and Smo transcripts increased, while Ptch1, Hdac2 and Hdac3 transcripts decreased. Regarding to the presence of SHH signaling molecules in two-cell embryos and their response to purmorphamine, it can be suggested that SHH signaling is probably active before embryonic genome activation in ovine embryos.

Effect of in vitro and in vivo conditions on development of parthenogenetic rabbit embryos after vitrification

Parthenote embryos offer multiple opportunities in biotechnological research, so it is important to analyse the possibilities for their cryopreservation in order to establish a biobank. The aim of this experiment was to determine the effect of culture conditions and vitrification on rabbit parthenogenetic embryos. Parthenotes were cultured under in vivo and in vitro conditions until day 3 (late morula/early blastocyst), when they were vitrified. Immediately after warming, they were newly cultured under in vivo and in vitro conditions till day 6 (blastocyst stage). Both culture conditions showed similar late morula/early blastocyst (0.39±0.056 vs. 0.46±0.043, for in vivo and in vitro, respectively) and blastocyst rates (0.12±0.068 vs. 0.13±0.070, for in vivo and in vitro, respectively). However, no parthenote was recovered when a combination of culture conditions was performed. To our best knowledge, this is the first demonstration of the ability of rabbit parthenogenetic embryos to develop after vitrification, with similar embryo development after in vivo or in vitro culture. Nevertheless, our results highlight the importance of culture conditions on the morphology of parthenote embryos. Therefore, we have described that special attention should be paid on culture conditions to generate parthenote embryos, with a view to their subsequent use, for example in embryonic stem cell production.

Cyclopamine did not affect mouse oocyte maturation in vitro but decreased early embryonic development

Hedgehog (Hh) pathway has been studied in various animal body life procedures and is suggested to be important for the development of multiple organs. The genes involved in the Hh signaling pathway were expressed in the ovary of mice, pigs and cattle. However, the function of Hh signaling pathway on oocyte maturation and early embryonic development is still controversial. We detected the effect of sonic hedgehog (Shh) and cyclopamine on the in vitro maturation of mouse oocytes and embryo development. The results showed that the presence of Shh or cyclopamine resulted in similar oocyte maturation to control groups. Shh did not improve early embryonic development. However, the supplement of cyclopamine depressed early embryo development. The mRNA of shh, ptch1, smo and gli1 were less detected in the denuded oocytes. The expression levels of ptch1 ascended from the uncleaved zygote to blastocyst stage. Smo or gli1 were expressed on a higher level at the two-cell or four-cell stage in early embryonic development separately. Therefore, Shh did not affect mouse oocyte maturation and early embryo development, but cyclopamine led to inhibited development of mouse early embryo. The effects of Hh signaling on the oocyte maturation and early embryo development might be species-specific.

Ascorbic acid improves the developmental competence of porcine oocytes after parthenogenetic activation and somatic cell nuclear transplantation

In this study, a dose-response assessment was performed to understand the relation between supplementation of media with L-ascorbic acid or vitamin C and porcine oocyte maturation and the in vitro development of parthenotes (PA) and handmade cloned (HMC) embryos. Various concentrations (0, 25, 50 and 100 µg/ml) of vitamin C supplemented in in vitro maturation (IVM) and culture (IVC) media were tested. None of these vitamin C additions affected nuclear maturation of oocytes, yet supplementation at 50 µg/ml led to significantly increased intracellular glutathione (GSH) levels and reduced reactive oxygen species (ROS). When cultured in IVM- and/or IVC-supplemented media, the group supplemented with 50 µg/ml of vitamin C showed improved cleavage rates, blastocyst rates and total cell numbers per blastocyst (P<0.05) compared with other groups (control, 25 µg/ml and 100 µg/ml). In contrast, supplementation with 50 µg/ml vitamin C decreased (P<0.05) the apoptosis index as compared with the groups supplemented with 100 µg/ml. In addition, even with a lower blastocyst rate to start with (37.6 vs. 50.3%, P<0.05), supplementation of HMC embryos with vitamin C ameliorated their blastocyst quality to the extent of PA embryos as indicated by their total cell numbers (61.2 vs. 59.1). Taken together, an optimized concentration of vitamin C supplementation in the medium not only improves blastocyst rates and total cell numbers but also reduces apoptotic indices, whereas overdosages compromise various aspects of the development of parthenotes and cloned porcine embryos.

Selection of the in vitro culture media influences mRNA expression of Hedgehog genes, Il-6, and important genes regarding reactive oxygen species in single murine preimplantation embryos

Background. The aim of this paper was to determine the influence of different in vitro culture media on mRNA expression of Hedgehog genes, il-6, and important genes regarding reactive oxygen species in single mouse embryos. Methods. Reverse transcription of single embryos either cultured in vitro from day 0.5 until 3.5 (COOK's Cleavage medium or Vitrolife's G-1 PLUS medium) or in vivo until day 3.5 post coitum. PCR was carried out for β-actin followed by nested-PCR for shh, ihh, il-6, nox, gpx4, gpx1, and prdx2. Results. The number of murine blastocysts cultured in COOK medium which expressed il-6, gpx4, gpx1, and prdx2 mRNA differed significantly compared to the in vivo group. Except for nox, the mRNA profile of the Vitrolife media group embryos varied significantly from the in vivo ones regarding the number of blastocysts expressing the mRNA of shh, ihh, il-6, gpx4, gpx1 and prdx2. Conclusions. The present study shows that different in vitro culture media lead to different mRNA expression profiles during early development. Even the newly developed in vitro culture media are not able to mimic the female reproductive tract. The question of long-term consequences for children due to assisted reproduction techniques needs to be addressed in larger studies.

Sonic hedgehog supplementation of oocyte and embryo culture media enhances development of IVF porcine embryos

We investigated the expression of sonic hedgehog (SHH) receptor PTCH1 and its co-receptor smoothened (SMO) in fertilized porcine embryos. Effects of exogenous SHH on embryonic development and expressions of survival- and pluripotency-related genes were also determined. We found that PTCH1 and SMO are expressed from two-cell to blastocyst embryos. When oocytes or fertilized embryos were respectively cultured in the maturation or embryo culture medium supplemented with SHH (0.5 μg/ml), their blastocyst rates and total cell numbers increased (P<0.05) compared with the untreated control. When cultured simultaneously in thein vitromaturation (IVM) andin vitroculture (IVC) media supplemented with SHH, the oocytes gained increased blastocyst rates and total cell numbers in an additive manner, with reduced apoptotic indices (P<0.05). Interestingly, SHH treatment did not affect the expression of theBCL2L1(BCL-XL) gene, yet reducedBAXexpression. Blastocysts cultured with various SHH regimes had similar pluripotency-related gene (POU5F1(OCT-4) andCDX2) expression levels, but blastocysts derived from SHH treatment during IVM had higherZPF42(REX01) expression (P<0.05). The highestZPF42expression was observed in the blastocysts derived from SHH-supplemented IVC and from dual IVM and IVC treatments. The levels of acetylated histone 3 (AcH3K9/K14) increased in the two-cell and the four-cell embryos when IVM and/or IVC media were supplemented with SHH (P<0.05). Our findings indicate that SHH conferred a beneficial effect on preimplantation development of porcine embryos, particularly when both IVM and IVC media were supplemented with SHH, and the effects may be further carried over from IVM to the subsequent embryonic development.