Staufen1 (STAU1) and Lin28B are RNA-binding proteins that are involved in neuronal differentiation as a function of post-transcriptional regulation. STAU1 triggers post-transcriptional regulation, ...including mRNA export, mRNA relocation, translation and mRNA decay. Lin28B also has multiple functions in miRNA biogenesis and the regulation of translation. Here, we examined the connection between STAU1 and Lin28B and found that Lin28B regulates the abundance of STAU1 mRNA via miRNA maturation. Decreases in the expression of both STAU1 and Lin28B were observed during neuronal differentiation. Depletion of STAU1 or Lin28B inhibited neuronal differentiation, and overexpression of STAU1 or Lin28B enhanced neuronal differentiation. Interestingly, the stability of STAU1 mRNA was modulated by miR-142-3p, whose maturation was regulated by Lin28B. Thus, miR-142-3p expression increased as Lin28B expression decreased during differentiation, leading to the reduction of STAU1 expression. The transcriptome from Staufen-mediated mRNA decay (SMD) targets during differentiation was analyzed, confirming that STAU1 was a key factor in neuronal differentiation. In support of this finding, regulation of STAU1 expression in mouse neural precursor cells had the same effects on neuronal differentiation as it did in human neuroblastoma cells. These results revealed the collaboration of two RNA-binding proteins, STAU1 and Lin28B, as a regulatory mechanism in neuronal differentiation.
Background
Alcohol exposure has been shown to cause devastating effects on neurobehavioral development in numerous animal and human studies. The alteration of DNA methylation levels in gene‐specific ...promoter regions has been investigated in some studies of human alcoholics. This study was aimed to investigate whether social alcohol consumption during periconceptional period is associated with epigenetic alteration and its generational transmission in the blood cells.
Methods
We investigated patterns of alcohol intake in a prospective cohort of 355 pairs of pregnant women and their spouses who reported alcohol intake during the periconceptional period. A subpopulation of 164 families was established for the epigenetic study based on the availability of peripheral blood and cord blood DNA. The relative methylation changes of dopamine transporter (DAT), serotonin transporter (SERT), and methyl CpG binding protein 2 (MeCP2) gene promoters were analyzed using methylation‐specific endonuclease digestion followed by quantitative real‐time polymerase chain reaction.
Results
The relative methylation level of the DAT gene promoter was decreased in the group of mothers reporting above moderate drinking (p = 0.029) and binge drinking (p = 0.037) during pregnancy. The relative methylation level of the DAT promoter was decreased in the group of fathers reporting heavy binge drinking (p = 0.003). The relative methylation levels of the SERT gene promoter were decreased in the group of newborns of light drinking mothers before pregnancy (p = 0.012) and during pregnancy (p = 0.003). The methylation level in the MeCP2 promoter region of babies whose mothers reported above moderate drinking during pregnancy was increased (p = 0.02). In addition, methylation pattern in the DAT promoter region of babies whose fathers reported heavy binge drinking was decreased (p = 0.049).
Conclusions
These findings suggest that periconceptional alcohol intake may cause epigenetic changes in specific locus of parental and newborn genomes as follows: Alcohol consumption decreases the methylation level of the DAT promoter region of the parent themselves, maternal alcohol drinking during the periconceptional period decreases the methylation level of the SERT promoter region of newborns, and maternal alcohol consumption increases the methylation level of the MeCP2 promoter region of newborns.
Human embryonic stem (hES) cells can be guided to differentiate into ventral midbrain-type neural precursor (NP) cells that proliferate in vitro by specific mitogens. We investigated the potential of ...these NP cells derived from hES cells (hES-NP) for the large-scale generation of human dopamine (DA) neurons for functional analyses and therapeutic applications. To address this, hES-NP cells were expanded in vitro for 1.5 months with six passages, and their proliferation and differentiation properties determined over the NP passages. Interestingly, the total hES-NP cell number was increased by > 2 x 10⁴-folds over the in vitro period without alteration of phenotypic gene expression. They also sustained their differentiation capacity toward neuronal cells, exhibiting in vitro pre-synaptic DA neuronal functionality. Furthermore, the hES-NP cells can be cryopreserved without losing their proliferative and developmental potential. Upon transplantation into a Parkinson's disease rat model, the multi-passaged hES-NP cells survived, integrated into the host striatum, and differentiated toward the neuronal cells expressing DA phenotypes. A significant reduction in the amphetamine-induced rotation score of Parkinson's disease rats was observed by the cell transplantation. Taken together, these findings indicate that hES-NP cell expansion is exploitable for a large-scale generation of experimental and transplantable DA neurons of human-origin.
The most frequent chromosomal aneuploidy is trisomy 21 (T21) that is caused by an extra copy of chromosome 21. The imbalance of whole genome including genes and microRNAs contributes to the various ...phenotypes of T21. However, the integrative association between genes and microRNAs in the T21 placenta has yet to be determined.
We analyzed the expressions of genes and microRNAs in the whole genomes of chorionic villi cells from normal and T21 human fetal placentas based on our prior studies. The functional significances and interactions of the genes and microRNAs were predicted using bioinformatics tools.
Among 110 genes and 34 microRNAs showing significantly differential expression between the T21 and normal placentas, the expression levels of 17 genes were negatively correlated with those of eight microRNAs in the T21 group. Of these 17 genes, 10 with decreased expression were targeted by five up-regulated microRNAs, whereas seven genes with increased expression were targeted by three down-regulated microRNAs. These genes were significantly associated with hydrogen peroxide-mediated programmed cell death, cell chemotaxis, and protein self-association. They were also associated with T21 and its accompanying abnormalities. The constructed interactive signaling network showed that seven genes (three increased and four decreased expressions) were essential components of a dynamic signaling complex (P = 7.77e-16).
In this study, we have described the interplay of genes and microRNAs in the T21 placentas and their modulation in biological pathways related to T21 pathogenesis. These results may therefore contribute to further research about the interaction of genes and microRNAs in disease pathogenesis.
Metformin is the most widely used anti-diabetic drug in the world. Recent evidence indicates that metformin could potentially inhibit tumorigenesis. In the present study, we found that metformin ...inhibited cell migration and invasion of phorbol 12-myristate 13-acetate-induced MCF-7 and tamoxifen-resistant MCF-7 breast cancer cells. This inhibition was correlated with the modulation of matrix metalloproteinase-9 (MMP9) via the suppression of its expression and proteolytic activity. These results indicate that metformin leads to the suppression of migration and invasion through regulation of MMP9 and it may have potential as an anticancer drug for therapy in human breast cancer, especially of chemoresistant cancer cells.
Directed methods for differentiating human embryonic stem cells (hESCs) into dopaminergic (DA) precursor cells using stromal cells co-culture systems are already well established. However, not all of ...the hESCs differentiate into DA precursors using these methods. HSF6, H1, H7, and H9 cells differentiate well into DA precursors, but CHA13 and CHA15 cells hardly differentiate. To overcome this problem, we modified the differentiation system to include a co-culturing step that exposes the cells to noggin early in the differentiation process. This was done using γ-irradiated noggin-overexpressing CF1-mouse embryonic fibroblasts (MEF-noggin) and MS5 stromal cells (MS5-noggin and MS5-sonic hedgehog). After directed differentiation, RT-PCR analyses revealed that engrailed-1 (En-1), Lmx1b, and Nurr1, which are midbrain DA markers, were expressed regardless of differentiation stage. Moreover, tyrosine hydroxylase (Th) and an A9 midbrain-specific DA marker (Girk2) were expressed during differentiation, whereas levels of Oct3/4, an undifferentiated marker, decreased. Immunocytochemical analyses revealed that protein levels of the neuronal markers TH and TuJ1 increased during the final differentiation stage. These results demonstrate that early noggin exposure may play a specific role in the directed differentiation of DA cells from human embryonic stem cells.
Reticulocytes contain both RNA and micro-organelles and represent the last stage of erythropoiesis before full maturation to red blood cells (RBCs). Even though there is continuing synthesis of ...hemoglobin and membrane-bound proteins in reticulocytes, the small amount of RNA that they contain has been regarded as non-functional residual material. Here we show that this residual RNA is both functional and essential for further reticulocyte maturation. Reticulocytes from which the remnant RNA had been removed by exposure to RNase did not survive or mature into RBCs in either humans or mice. Conversely, reticulocytes treated with an RNase Inhibitor were able to form normal biconcave cells. Similarly, poor survival was also seen in reticulocytes in which protein synthesis had been blocked. To identify the signaling pathways involved we isolated RNAs in reticulocytes versus those present in fully matured erythroblasts cultured from hematopoietic stem cells. RNAs found in erythroblasts were related to exocytosis, metabolism, and signal transduction all of which are critical for maturation through reticulocyte and into a fully mature, biconcave erythrocyte. Our results suggest that the mRNA in reticulocytes has to be translated into novel proteins that act to preserve mitochondria and maintain cell membrane integrity as reticulocytes mature. These results enhance our understanding of the final stage of erythropoiesis and may clarify why in vitro-generated reticulocytes for transfusion purposes survive poorly.
Summary
Pure subtelomeric deletion of the long arm of chromosome 6 is rare. The frequency of this deletion accounts for approximately 0.05% of subjects with intellectual disability and developmental ...delay with or without dysmorphic features. Common phenotypes associated with this deletion include intellectual disability, developmental delay, dysmorphic features, seizure, hypotonia, microcephaly and hypoplasia of the corpus callosum. The smallest overlapped region is approximately 0.4 Mb, and contains three known genes. Of these genes, TBP has been considered as a plausible candidate gene for the phenotype in patients with a subtelomeric 6q deletion. Analysis of the breakpoints in 14 cases revealed a potential common breakpoint interval 8.0–9.0 Mb from the chromosome 6q terminus where the FRA6E fragile site exists and the PARK2 gene is located. This suggests that breakage at the FRA6E fragile site may be the mechanism behind chromosome 6q subtelomeric deletion in some of the cases.
Fanconi anemia (FA) is a recessively inherited multigene disease characterized by congenital defects, progressive bone marrow failure, and heightened cancer susceptibility. Monoubiquitination of the ...FA pathway member FANCD2 contributes to the repair of replication stalling DNA lesions. However, cellular regulation of FANCD2 monoubiquitination remains poorly understood. In the present study, we identified the miR-302 cluster as a potential regulator of FANCD2 by bioinformatics analysis. MicroRNAs (miRNAs) are the major posttranscriptional regulators of a wide variety of biological processes, and have been implicated in a number of diseases. Expression of the exogenous miR-302 cluster (without miR-367) reduced FANCD2 monoubiquitination and nuclear foci formation. Furthermore, miR-302 cells showed extensive chromosomal breakage upon MMC treatment when compared to mock control cells. Taken together, our results suggest that overexpression of miR-302 plays a critical role in the regulation of FANCD2 monoubiquitination, resulting in characteristic defects in DNA repair within cells.
•miR-302 binds to the 3′UTR promoter of the FANCD2 gene to regulate gene expression.•miR-302 cluster down-regulates FANCD2 protein expression.•miR-302 cluster reduces FANCD2 monoubiquitination and nuclear foci formation.•miR-302 exhibits the characteristic defects in DNA repair in cells.
Epigenetic mechanisms provide an interface between environmental factors and the genome and are influential in various diseases. These mechanisms, including DNA methylation, influence the regulation ...of development, differentiation, and establishment of cellular identity. Here, we performed high-throughput methylome profiling to determine whether differential patterns of DNA methylation correlate with Down syndrome (DS).
We extracted DNA from the chorionic villi cells of five normal and five DS fetuses at the early developmental stage (12-13 weeks of gestation). Methyl-capture sequencing (MC-Seq) was used to investigate the methylation levels of CpG sites distributed across the whole genome to identify differentially methylated CpG sites (DMCs) and regions (DMRs) in DS. New functional annotations of DMR genes using bioinformatics tools were predicted.
DNA hypermethylation was observed in DS fetal chorionic villi cells. Significant differences were evident for 4,439 DMCs, including hypermethylation (n = 4,261) and hypomethylation (n = 178). Among them, 140 hypermethylated DMRs and only 1 hypomethylated DMR were located on 121 genes and 1 gene, respectively. One hundred twenty-two genes, including 141 DMRs, were associated with heart morphogenesis and development of the ear, thyroid gland, and nervous systems. The genes were significantly associated with DS and various diseases, including hepatopulmonary syndrome, conductive hearing loss, holoprosencephaly, heart diseases, glaucoma, and musculoskeletal abnormalities.
This is the first study to compare the whole-epigenome DNA methylation pattern of the chorionic villi cells from normal and DS fetuses at the early developmental-stage using MC-seq. Overall, our results indicate that the chorionic villi cells of DS fetuses are hypermethylated in all autosomes and suggested that altered DNA methylation may be a recurrent and functionally relevant downstream response to DS in human cells. This study provides basic information for future research focused on the pathophysiology of the DS and its potential effects, as well as the role DNA methylation plays in the early developmental stage of DS fetuses.
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