Ginsenoside Rb1 protects porcine oocytes against methylglyoxal damage thus it improves the quality of parthenogenetic activation and in vitro fertilization embryos

Panax ginseng, a functional food, has been widely used as an edible nourishment and medicinal supplement. Ginsenoside Rb1 is a major bioactive ingredient of ginseng, which shows very specific anti-apoptosis and anti-oxidant activities. Methylglyoxal (MGO) is one of intermediate products of glucose metabolism, which is absorbed easily from high sugar foods or carbonated beverages. It may involve in a variety of detrimental processes in vivo. However, it has not been fully explored the effects of ginsenoside Rb1 on MGO-induced oocytes damage. This study found that MGO-induced DNA damage and mitochondrial dysfunction result in the failure of porcine oocytes maturation and low in vitro development capacity of parthenogenetic activation (PA) and in vitro fertilization (IVF) embryos. Conversely, Rb1 supplementation recovered the rate of maturation, and improved in vitro development capacity of PA and IVF embryos. Rb1 also provided porcine oocytes a lower level of reactive oxygen species production, higher level of ATP content and mitochondrial membrane potential, and stimulated pluripotency gene expression in blastocysts. The findings of this study reveal ginsenoside Rb1 protects porcine oocyte from the cytotoxicity effects of methylglyoxal and provides novel perspectives for the protection of reproduction system by functional food of ginseng.

Shift from slow- to fast-twitch muscle fibres in skeletal muscle of newborn heterozygous and homozygous myostatin-knockout piglets

Myostatin (MSTN) is a member of the transforming growth factor-β superfamily that negatively regulates skeletal muscle development. A lack of MSTN induces muscle hypertrophy and increases formation of fast-twitch (Type II) muscle fibres. This study investigated muscle development in newborn heterozygous (MSTN+/-) and homozygous (MSTN-/-) MSTN-knockout piglets. Detailed morphological and gene and protein expression analyses were performed of the biceps femoris, semitendinosus and diaphragm of MSTN+/-, MSTN-/- and wild-type (WT) piglets. Haematoxylin-eosin staining revealed that the cross-sectional area of muscle fibres was significantly larger in MSTN-knockout than WT piglets. ATPase staining demonstrated that the percentage of Type IIb and IIa muscle fibres was significantly higher in MSTN-/- and MSTN+/- piglets respectively than in WT piglets. Western blotting showed that protein expression of myosin heavy chain-I was reduced in muscles of MSTN-knockout piglets. Quantitative reverse transcription-polymerase chain reaction revealed that, compared with WT piglets, myogenic differentiation factor (MyoD) mRNA expression in muscles was 1.3- to 2-fold higher in MSTN+/- piglets and 1.8- to 3.5-fold higher MSTN-/- piglets (P<0.05 and P<0.01 respectively). However, expression of myocyte enhancer factor 2C (MEF2C) mRNA in muscles was significantly lower in MSTN+/- than WT piglets (P<0.05). MSTN plays an important role in skeletal muscle development and regulates muscle fibre type by modulating the gene expression of MyoD and MEF2C in newborn piglets.

The protective role of ginsenoside compound K in porcine oocyte meiotic maturation failed caused by benzo(a)pyrene during in vitro maturation

Benzo(a)pyrene (BaP) is a pollutant and carcinogen derived from air pollution. It causes serious damage to reproductive system, especially ovary. Ginseng is always used in food and traditional medicine as a nutraceuticals or herbal medicine. Ginsenoside compound K (CK) is a major bioactive ingredient of ginseng, that shows very specific anti-apoptosis, anti-oxidant, and anti-inflammatory activities and thus, it protects cells from damage. The aim of this study was to investigate the effects of CK on the BaP-induced inhibition of the in vitro maturation of porcine oocytes and their subsequent embryonic development capacity. We found that supplementation with 10 μg mL^-1 CK during in vitro maturation significantly increased maturation rate (P < 0.05) and the expression level of related genes after damage induced by 40 μM BaP treatment. In addition, reactive oxygen species (ROS) levels significantly decreased and ATP content and mitochondrial membrane potential (MMP) increased after CK supplementation (P < 0.05). The competence for embryonic development was improved by the induction of pluripotency gene expression and the inhibition of apoptosis after CK supplementation of BaP-treated oocytes. Supplementation with 10 μg mL^-1 CK improved porcine oocyte maturation and subsequent embryonic development of parthenogenetic activation (33.01 vs. 20.92, P < 0.05) and in vitro fertilization (24.01 vs. 16.52, P < 0.05) by increasing antioxidant activity and improving mitochondrial function after BaP-induced damage.

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.

Baicalin improves IVM of pig oocytes and subsequent preimplantation embryo development by inhibiting apoptosis

Baicalin, a monomer of flavonoids extracted from dried roots of Scutellaria baicalensis, is used to treat female infertility. However, the effect of baicalin on oocyte maturation is unknown. In this study we investigated the effects of baicalin on the IVM of pig oocytes and subsequent embryo development following parthenogenetic activation (PA). We found that 0.1µgmL-1 baicalin significantly (P<0.05) increased the IVM rate of oocytes compared with the non-treatment (control) group by reducing levels of reactive oxygen species (ROS). In addition, the mRNA expression of genes related to nuclear maturation and cumulus cell expansion, mitochondrial membrane potential and ATP content was significantly (P<0.05) higher in baicalin-treated than control oocytes. To determine whether baicalin treatment during IVM of pig oocytes improves subsequent development of PA embryos, we measured the cleavage and blastocyst formation rates, as well as the number of cells per blastocyst. All these parameters were significantly (P<0.05) higher in the baicalin-treated than control group. In conclusion, this study demonstrates that baicalin improves pig oocyte maturation and subsequent embryo development invitro by inhibiting production of ROS and reducing apoptosis in oocytes.

Comparison of internal organs between myostatin mutant and wild-type piglets

BACKGROUND

Myostatin (MSTN) negatively regulates skeletal muscle development; however, its functions in internal organs have not been thoroughly investigated. Here, we compared the morphological, molecular, and biological characteristics of the heart, liver, spleen, lungs, kidneys, and tongue of homozygous MSTN mutant (MSTN^-/- ), heterozygous MSTN mutant (MSTN^+/- ), and wild-type (WT) piglets.

RESULTS

The heart and liver were lighter in MSTN^-/- piglets than in MSTN^+/- piglets, while the tongue was heavier in MSTN^-/- piglets than in WT piglets (P < 0.05). Furthermore, the tongue was longer in MSTN^-/- piglets than in WT piglets, and myofibers of the tongue were significantly larger in the former piglets than in the latter ones (P < 0.01). mRNA expression of MSTN in all organs was significantly lower in MSTN^-/- and MSTN^+/- piglets than in WT piglets (P < 0.05). Meanwhile, mRNA expression of follistatin, which is closely related to MSTN, in the heart and liver was significantly higher in MSTN^-/- piglets than in MSTN^+/- and WT piglets (P < 0.05). In addition, protein expression of MSTN in the heart, kidneys, and tongue was significantly lower in MSTN^-/- piglets than in WT piglets (P < 0.01).

CONCLUSION

These results suggest that MSTN is widely expressed and has marked effects in multiple internal organs. Myostatin has crucial functions in regulating internal organ size, especially the tongue. © 2019 Society of Chemical Industry.

Hairless-knockout piglets generated using the clustered regularly interspaced short palindromic repeat/CRISPR-associated-9 exhibit abnormalities in the skin and thymus

The nuclear receptor corepressor Hairless (HR) interacts with nuclear receptors and controls expression of specific target genes involved in hair morphogenesis and hair follicle cycling. Patients with HR gene mutations exhibit atrichia, and in rare cases, immunodeficiency. Pigs with HR gene mutations may provide a useful model for developing therapeutic strategies because pigs are highly similar to humans in terms of anatomy, genetics, and physiology. The present study aimed to knockout the HR gene in pigs using the clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR-associated-9 (Cas9) system and to investigate the molecular and structural alterations in the skin and thymus. We introduced a biallelic mutation into the HR gene in porcine fetal fibroblasts and generated nine piglets via somatic cell nuclear transfer. These piglets exhibited a lack of hair on the eyelids, abnormalities in the thymus and peripheral blood, and altered expression of several signaling factors regulated by HR. Our results indicate that introduction of the biallelic mutation successfully knocked out the HR gene, resulting in several molecular and structural changes in the skin and thymus. These pigs will provide a useful model for studying human hair disorders associated with HR gene mutations and the underlying molecular mechanisms.

The Histone Deacetylase Inhibitor, CI994, Improves Nuclear Reprogramming and In Vitro Developmental Potential of Cloned Pig Embryos

Epigenetic reprogramming and somatic cell nuclear transfer (SCNT) cloning efficiency were recently enhanced using histone deacetylase inhibitors (HDACis). In this study, we investigated the time effect of CI994, an HDACi, on the blastocyst formation rate, acetylation levels of H3K9 and H4K12, DNA methylation levels of anti-5-methylcytosine (5mC), and some mRNA expression of pluripotency-related genes in pig SCNT embryos. Treatment with 10 μM CI994 for 24 hours significantly improved the blastocyst formation rate of SCNT embryos in comparison with the untreated group (p < 0.05). Moreover, average fluorescence intensities of H3K9 and H4K12 in CI994-treated embryos were remarkably increased at the pseudo-pronuclear stage, but not at the blastocyst stage. The intensity of POU5F1 was higher in CI994-treated blastocysts than in control blastocysts, whereas that of 5mC did not differ between the two groups. The percentage of apoptotic cells in blastocysts was significantly higher in the untreated group than in the CI994-treated group. mRNA levels of POU5F1 and SOX2 were significantly increased in the CI994-treated group. These observations suggest that optimum exposure (10 μM for 24 hours) to CI994 after activation elevates the level of histone acetylation and subsequently improves the in vitro development of pig SCNT embryos.

Cotreatment with RepSox and LBH589 improves the in vitro developmental competence of porcine somatic cell nuclear transfer embryos

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

The cyclin-dependent kinase inhibitor, JNJ-7706621, improves in vitro developmental competence of porcine parthenogenetic activation and somatic cell nuclear transfer embryos

In this study we examined the effects of JNJ-7706621, a cyclin-dependent kinase inhibitor, on the in vitro growth of pig embryos that had been produced either by parthenogenetic activation (PA) or somatic cell nuclear transfer (SCNT). A significantly higher percentage of PA embryos reached the blastocyst stage by Day 7 after exposure to 10 µM JNJ-7706621 for 4 h compared with embryos exposed to 5 µg mL−1 cytochalasin B for 4 h (P < 0.05). Similarly, the rate of Tyr15 phosphorylation of the complex of cyclin and p34cdc2 (CDK1) was significantly elevated in the JNJ-7706621-treated embryos compared with embryos exposed to cytochalasin B or non-treated controls (P < 0.05). In contrast, Thr161 phosphorylation of CDK1 was significantly lower in the JNJ-7706621-treated group compared with the cytochalasin B-treated as well as the non-treated group (P < 0.05). Similarly, the level of M-phase-promoting factor (MPF) in embryos was significantly lower in the JNJ-7706621-treated group compared with the cytochalasin B-treated and non-treated groups (P < 0.05). In addition, more SCNT embryos reached the blastocyst stage after treatment with JNJ-7706621 than following exposure to cytochalasin B (P < 0.05). In conclusion, these results reveal that exposure to 10 µM JNJ-7706621 for 4 h improves early development of PA and SCNT porcine embryos by suppressing the activity of CDK1 and a concomitant reduction in the level of MPF.

Quisinostat treatment improves histone acetylation and developmental competence of porcine somatic cell nuclear transfer embryos

Abnormal epigenetic modifications are considered a main contributing factor to low cloning efficiency. In the present study, we explored the effects of quisinostat, a novel histone deacetylase inhibitor, on blastocyst formation rate in porcine somatic-cell nuclear transfer (SCNT) embryos, on acetylation of histone H3 lysine 9 (AcH3K9), and on expression of POU5F1 protein and apoptosis-related genes BAX and BCL2. Our results showed that treatment with 10 nM quisinostat for 24 hr significantly improved the development of reconstructed embryos compared to the untreated group (19.0 ± 1.6% vs. 10.2 ± 0.9%; p < 0.05). Quisinostat-treated SCNT embryos also possessed significantly increased AcH3K9 at the pseudo-pronuclear stage (p < 0.05), as well as improved immunostaining intensity for POU5F1 at the blastocyst stage (p < 0.05). While no statistical difference in BAX expression was observed, BCL2 transcript abundance was significantly different in the quisinostat-treated compared to the untreated control group. Of the 457 quisinostat-treated cloned embryos transferred into three surrogates, six fetuses developed from the one sow that became pregnant. These findings suggested that quisinostat can regulate gene expression and epigenetic modification, facilitating nuclear reprogramming, and subsequently improving the developmental competence of pig SCNT embryos and blastocyst quality.

Generation of cloned adult muscular pigs with myostatin gene mutation by genetic engineering

Skeletal muscle is the most economically valuable tissue in meat-producing animals and enhancing muscle growth in these species may enhance the efficiency of meat production.