Epigenetic status of H19/IGF2 and SNRPN imprinted genes in aborted and successfully derived embryonic stem cell lines in non-human primates

Analysis of developmental imprinting dynamics in primates using SNP-free methods to identify imprinting defects in cloned placenta

Our knowledge of genomic imprinting in primates is lagging behind that of mice largely because of the difficulties of allelic analyses in outbred animals. To understand imprinting dynamics in primates, we profiled transcriptomes, DNA methylomes, and H3K27me3 in uniparental monkey embryos. We further developed single-nucleotide-polymorphism (SNP)-free methods, TARSII and CARSII, to identify germline differentially methylated regions (DMRs) in somatic tissues. Our comprehensive analyses showed that allelic DNA methylation, but not H3K27me3, is a major mark that correlates with paternal-biasedly expressed genes (PEGs) in uniparental monkey embryos. Interestingly, primate germline DMRs are different from PEG-associated DMRs in early embryos and are enriched in placenta. Strikingly, most placenta-specific germline DMRs are lost in placenta of cloned monkeys. Collectively, our study establishes SNP-free germline DMR identification methods, defines developmental imprinting dynamics in primates, and demonstrates imprinting defects in cloned monkey placenta, which provides important clues for improving primate cloning.

The genetic script of metastasis

Metastasis is a pivotal event that changes the course of cancers from benign and treatable to malignant and difficult to treat, resulting in the demise of patients. Understanding the genetic control of metastasis is thus crucial to develop efficient and sustainable targeted therapies. Here we discuss the alterations in epigenetic mechanisms, transcription, chromosomal instability, chromosome imprinting, non-coding RNAs, coding RNAs, mutant RNAs, enhancers, G-quadruplexes, and copy number variation to dissect the genetic control of metastasis. We conclude that the genetic control of metastasis is predominantly executed through epithelial to mesenchymal transition and evasion of cell death. We discuss how genetic regulatory mechanisms can be harnessed for therapeutic purposes to achieve sustainable control over cancer metastasis.

c-Myc-mediated SNRPB upregulation functions as an oncogene in hepatocellular carcinoma

Dysregulation of genes involved in alternative splicing contributes to hepatocarcinogenesis. SNRPB, a component of spliceosome, is implicated in human cancers, yet its clinical significance and biological function in hepatocellular carcinoma (HCC) remains unknown. Here, we show that SNRPB expression is increased in HCC tissues, compared with the nontumorous tissues, at both messenger RNA and protein levels in two independent cohorts. High expression of SNRPB is significantly associated with higher pathological grade, vascular invasion, serum alpha-fetoprotein level, tumor metastasis, and poor disease-free and overall survivals. Luciferase reporter and chromatin immunoprecipitation assays demonstrate that SNRPB upregulation in HCC is mediated by c-Myc. Positive correlation is found between SNRPB and c-Myc expression in clinical samples. In vitro studies show that ectopic expression of SNRPB promotes HCC cell proliferation and migration, whereas knockdown of SNRPB results in the opposite phenotypes. Collectively, our data suggest SNRPB function as an oncogene and serve as a potential prognostic factor in HCC.

Long Noncoding RNA: Function and Mechanism on Differentiation of Mesenchymal Stem Cells and Embryonic Stem Cells

Background:

Long suspected as transcriptional noise, recently recognized, long non-coding RNAs (lncRNAs) are emerging as an indicator, biomarker and therapy target in the physiologic and pathologic process. Mesenchymal stem cells and embryonic stem cells are important source for normal and therapeutic tissue repair. However, the mechanism of stem cell differentiation is not completely understood. Research on lncRNAs may provide novel insights into the mechanism of differentiation process of the stem cell which is important for the application of stem cell therapy. The lncRNAs field is still very young, new insights into lncRNAs function are emerging to a greater understanding of biological processes.

Objective:

In this review, we summarize the recent researches studying lncRNAs and illustrate how they act in the differentiation of the mesenchymal stem cells and embryonic stem cells, and discuss some future directions in this field.

Results:

Numerous lncRNAs were differentially expressed during differentiation of mesenchymal stem cells and embryonic stem cells. LncRNAs were able to regulate the differentiation processes through epigenetic regulation, transcription regulation and post-transcription regulation.

Conclusion:

LncRNAs are involved in the differentiation process of mesenchymal stem cells and embryonic stem cells, and they could become promising indicator, biomarker and therapeutic targets in the physiologic and pathologic process. However, the mechanisms of the role of lncRNAs still require further investigation.

Effect of abnormal GpG methylation in the second trimester of pregnancy on adverse health risk of offspring

Effect of abnormal GpG methylation in amniotic fluid cells during the second trimester of pregnancy on adverse health risk of offspring was investigated. In total, 237 sets of amniotic fluid cells were collected from patients who received prenatal diagnosis in the Third Affiliated Hospital of Guangzhou Medical University (Guangzhou, China) from April 2010 to October 2011. Among them, 156 sets were from singleton and 81 sets were from twins. H19 gene was amplified by PCR, and the product was purified and pyrosequencing was used to detect the DNA methylation level of GapG. Follow-up records of the birth outcomes of pregnant women's offspring were collected. Positive rate of DNA amplification in 200 cases of amniotic fluid cells was 84.4% (200/237). Average age of singleton pregnancies was higher than that of twins (P<0.05), and no significant differences were found in gestational age and PCR amplification rate (P>0.05). There was no difference in the methylation level of GapG between singleton and twins (P>0.05), but the abnormal methylation rate of GapG1 in twin fetuses was significantly higher than that of singleton (20.3 vs. 3.6%, χ²=8.364, P=0.004). Offspring sex, singleton or twins, mode of delivery, time of pregnancy, and low birth weight showed no significant effect on GapG methylation level of H19 in the second trimester of pregnancy. No offspring deformities were found regardless of the increased or decreased degree of methylation (P>0.05). The number of fetuses born may cause abnormal GapG1 methylation, but no effect of GapG methylation on the adverse health risk of offspring was found.