Low efficiency of somatic cell nuclear transfer (SCNT) is attributed to incomplete reprogramming of transferred nuclei into oocytes. Trichostatin A (TSA), a histone deacetylase inhibitor, has been used to enhance nuclear reprogramming following SCNT. However, the molecular mechanism of TSA for the improvement of the preimplantation embryo and fetal development following SCNT is not known. The present study investigates embryo viability and gene expression of cloned bovine preimplantation embryos in the presence and absence of TSA compared to embryos produced by in vitro fertilization or parthenogenetic activation. Our results indicated that TSA treatment significantly improved total and inner cell mass (ICM) cell number and ratio of ICM:trophectoderm (TE) and also decreased the apoptotic index including total, ICM, and ratio of ICM:TE. Four apoptotic-related genes, Bcl-xL, survivin, Bcl2-associated X protein (Bax), and caspase 3 (Casp3), and four pluripotency/differentiation related genes, Oct4, SRY (sex determining region Y)-box 2 (Sox2), Cdx2, and colony-stimulating factor 1 receptor (Csf1r), were measured by real-time RT-PCR. TSA treatment resulted in the high expression of antiapoptotic gene Bcl-xL and low expression of pro-apoptotic gene Bax compared to untreated NT embryos, fertilized embryos, or parthenotes. Furthermore, mRNA expression of Cdx2 was higher in NT-TSA embryos than in NT and in vitro fertilization (IVF) counterparts. Additionally, low expression of microRNA (mir)-21 in NT embryos was enhanced following TSA treatment. These results suggest that TSA positively regulates nuclear reprogramming, and TSA may increased resistance or reduced signal for induction of apoptosis.

Bisphenol A (BPA) is an environmental contaminant widely used in the plastic industry. BPA has been demonstrated to be an endocrine disruptor and has an adverse effect on the embryonic development of mammals. However, the mechanism of action of BPA is limited. In this study, we investigated the role and mechanism of BPA in porcine embryonic development. First, the parthenotes were treated with different concentrations of BPA. We found that blastocyst formation was impaired and the parthenotes were arrested at the 4-cell stage after treatment with 100 μm BPA. Second, ROS increased following the addition of BPA, which further caused mitochondrial damage, and cytochrome c was released from the mitochondria to induce apoptosis. The adaptive response was demonstrated through LC3 immunofluorescence staining and by assessing autophagy-related gene expression. In addition, BPA caused DNA damage through the p53-p21 signaling pathway. Thus, our results indicate that BPA displays an adverse effect on porcine early embryonic development through mitochondrial and DNA damage.

The quality of milk is inseparable from its milk components, and fatty acid content is a key factor affecting the quality of milk. In this study, the miRNA and mRNA profiles of the bovine mammary gland tissue during the dry period and the peak lactation period were determined through high-throughput sequencing. In total, 72 miRNA−mRNA regulatory pathways were screened, including miR-128/PPARGC1A regulatory pathways. miR-128 can directly target PPARGC1A and inhibit its expression. In addition, the study also observed that there was a miR-128 binding site in the sequence of the circular RNA circ11103, and circ11103 significantly reduced the expression of miR-128. circ11103 upregulated the triglyceride levels in bovine mammary epithelial cells (BMECs) and increased the contents of unsaturated fatty acids. However, miR-128 decreased triglyceride and cholesterol levels in BMECs. This study aims to analyze the mechanism governing the regulatory effect of circ11103 on milk fat metabolism, which provides new insights into improving milk quality.

Abnormal epigenetic reprogramming of donor nuclei after somatic cell nuclear transfer (SCNT) is thought to be the main cause of low cloning efficiencies. A growing body of evidence has demonstrated a positive role of Scriptaid, a histone deacetylase inhibitor (HDACi) that belongs to an existing class of hydroxamic acid-containing HDACis, on the development competence of cloned embryos in many species. The present study investigated the effects of Scriptaid on the development of porcine SCNT embryos in vitro and its mechanism. Treatment with 300 or 500 nM Scriptaid for 20 h after activation significantly increased the percentage of SCNT embryos that developed to the blastocyst stage and the total number of cells per blastocyst and significantly decreased the percentage of apoptotic cells in blastocysts. Scriptaid treatment significantly increased the level of histone H3 acetylated at K9 and the conversion of 5-methylcytosine into 5-hydroxymethylcytosine and significantly decreased the level of histone H3 trimethylated at K9 at the pronuclear stage. As a potential mechanism for the DNA methylation changes, our results showed that the expression of DNA methyltransferase 1 was frequently down-regulated in Scriptaid-treated embryos in comparison with untreated embryos and was inversely correlated to endogenous microRNA-152 (miR-152). Taken together, these findings illustrated a crucial functional crosstalk between miR-152 and DNMT1. Meanwhile, mRNA and protein levels of POU5F1 and CDX2 were increased in Scriptaid-treated embryos. mRNA levels of Caspase3, and Bax were significantly decreased and that of Bcl-xL was significantly increased in Scriptaid-treated embryos. In conclusion, these observations would contribute to uncover the nuclear reprogramming mechanisms underlying the effects of Scriptaid on the improvement of porcine SCNT embryos.

MicroRNAs (miRNAs) repress target genes at the post-transcriptional level and play important roles in development and cell lineage decisions. In vertebrates, however, both the targets of miRNAs and their expression profiles during development are poorly understood. Thus far, 326 human miRNAs, 249 mouse miRNAs, and 195 rat miRNAs have been identified. Even though the pig is a promising animal model in regenerative biology, as well as in livestock production, only 54 pig miRNAs have been identified. Here, we report the identification of 58 new pig miRNAs. We conducted a homology search using either human or mouse miRNAs genes queried against the pig genome. The new pig miRNAs consist of 23 miRNAs showing homology to mouse, 21 showing homology to human, and 16 showing homology to both human and mouse. The expression profile of 6 miRNAs were analyzed by Northern blot analysis isolated from porcine tissues: ovary, heart, kidney, liver, and pancreas.