Methylation and demethylation of DNA are the complementary processes of epigenetic regulation. These two types of regulation influence a diverse array of cellular activities, including the maintenance of pluripotency and self-renewal in embryonic stem cells. It was generally believed that DNA demethylation occurs passively over several cycles of DNA replication and that active DNA demethylation is rare. Recently, evidence for active DNA demethylation has been obtained in several cancer, neuronal, and embryonic stem cell lines. Studies in embryonic stem cell models, however, suggested that active DNA demethylation might be restricted to the early development of progenitor cells. Whether active demethylation is involved in terminal differentiation of adult stem cells is poorly understood. We provide evidence that active DNA demethylation does occur during terminal specification of stem cells in an adipose-derived mesenchymal stem cell-derived osteogenic differentiation model. The medium CpG regions in promoters of the Dlx5, Runx2, Bglap, and Osterix osteogenic lineage-specific genes were demethylated during the increase in gene expression associated with osteogenic differentiation. The growth arrest and DNA damageinducible protein GADD45A was up-regulated in these processes. Knockdown of GADD45A led to hypermethylation of Dlx5, Runx2, Bglap, and Osterix promoters, followed by suppression of the expression of these genes and interruption of osteogenic differentiation. These results reveal that GADD45A plays an essential role in gene-specific active DNA demethylation during adult stem cell differentiation. They enhance the current knowledge of osteogenic specification and may also lead to a better understanding of the common mechanisms underlying epigenetic regulation in adult stem cell differentiation.Methylation of genomic DNA is one of the most important epigenetic mechanisms for gene regulation and is critical for a variety of cellular activities, including X chromosome inactivation, genomic imprinting, chromatin modification, and the silencing of endogenous genes (1). Alterations in DNA methylation are linked to many diseases, including imprinting disorders, autoimmune syndromes, and some cancers (2, 3). In humans and mammals, DNA methylation predominantly occurs at CpG dinucleotides that are largely depleted from the genome except at short genomic regions called CpG islands.Methylation is mediated by a number of DNA methyltransferases (DNMT), 3 including maintenance enzyme DNMT1 and de novo methyltransferases DNMT3A/3B (4, 5).In contrast to DNA methylation, less is known about DNA demethylation. It was generally believed that DNA demethylation occurred mainly by passive processes during DNA replication (6), although the occurrence of active DNA demethylation has long been elusive (7). Recently, active DNA demethylation was demonstrated in several cells, such as human embryonic kidney cells, breast cancer cells, T cells, and neurons (8 -12), and several functions of active demethylation have been described (8 -...

Although epigenetic modulation is critical for a variety of cellular activities, its role in erythropoiesis remains poorly understood. Teneleven translocation (TET) molecules participate in methylcytosine (5mC) hydroxylation, which results in DNA demethylation in several biological processes. In this research, the role of TETs in erythropoiesis was investigated by using the zebrafish model, where three TET homologs were identified. These homologs share conserved structural domains with their mammalian counterparts. Zebrafish TETs mediate the conversion of 5mC to hydroxymethylcytosine (5hmC) in zebrafish embryos, and the deletion of TET2 inhibits erythropoiesis by suppressing the expression of the scl, gata-1, and cmyb genes. TET2-upregulated lineage-specific genes and erythropoiesis are closely associated with the occurrence of 5hmC and demethylation in the intermediate CpG promoters (ICPs) of scl, gata-1, cmyb, which frequently occur at specific regions or CpG sites of these ICPs. Moreover, TET2 regulates the formation and differentiation of erythroid progenitors, and deletion of TET2 leads to erythrocyte dysplasia and anemia. Here, we preliminarily proved that TET2 plays an essential role in erythrocyte development by regulating lineage-specific genes via DNA oxidative demethylation. This report is anticipated to broaden current information on hematopoiesis and pathogenesis of hematopoiesis-related diseases.

MicroRNA-25 (miR-25) has recently been found to be involved in many critical processes in human malignancies. We aimed to investigate the expression pattern and prognostic role of miR-25 in colorectal cancer. Colorectal cancer and adjacent normal specimens from 186 patients who had not received neoadjuvant chemotherapy were collected. The expression of miR-25 was detected with a quantitative real-time PCR assay, and the association of miR-25 with overall patient survival was analyzed via statistical analysis. The results indicated that the level of miR-25 expression was significantly elevated in colorectal cancer compared with the level observed in the adjacent normal tissue. It was also demonstrated that miR-25 expression is associated with tumor invasion, lymph node metastasis, distant metastasis and the TNM stage of colorectal cancer. In addition, a Kaplan-Meier analysis revealed that an increased level of miR-25 expression is associated with a poor overall survival of patients. A multivariate survival analysis also indicated that miR-25 is an independent prognostic marker after adjusting for known prognostic factors. These results prove that miR-25 expression is increased in colorectal cancer and is associated with tumor progression. This study also provides the first evidence that miR-25 is an independent prognostic factor for patients with colorectal cancer, indicating the potential role of miR-25 as a highly specific and sensitive biomarker.

Background This study aims to provide an updated assessment of the efficacy of optimized enteral nutrition (EN) delivery by implementing the volume-based feeding (VBF) protocol in critically ill patients. Methods We updated our previous literature retrieval with no language restrictions. The inclusion criteria were:1) Participants: Critically ill patients (Patients who was admitted in ICU; 2) Intervention: The VBF protocol was adopted for EN administration; 3) Comparison: The rate-based feeding (RBF) protocol was adopted for EN administration; 4) Major outcomes: EN nutrition delivery. The exclusion criteria included participants aged < 18 years, duplicated literature, animal and cellular experiments, and studies lacking any of the outcomes mentioned in the inclusion criteria. The databases included MEDLINE (through PubMed), Web of Science, Cochrane Library, Chinese Biomedical Literature Service System (SinoMed), Wanfang Data Knowledge Service Platform, and China National Knowledge Infrastructure. Result Sixteen studies involving a total of 2896 critically ill patients are included in the updated meta-analysis. Compared with the previous meta-analysis, nine new studies were added that included 2205 more patients. The VBF protocol significantly improved energy (MD = 15.41%, 95% CI: [10.68, 20.14], p < 0.00001) and protein (MD = 22.05%, 95% CI: [10.89, 33.22], p = 0.0001) delivery. The patients in the VBF group stayed in the ICU for a shorter time (MD = 0.78, 95% CI: [0.01, 1.56], p = 0.05). The VBF protocol did not increase the risk of death (RR = 1.03, 95% CI: [0.85, 1.24], p = 0.76) or prolong the mechanical ventilation duration (MD = 0.81, 95% CI: [-0.30,1.92], p = 0.15). In addition, the VBF protocol did not affect EN complications, such as diarrhea (RR = 0.91, 95% CI: [0.73, 1.15], p = 0.43), emesis (RR = 1.23, 95% CI: [0.76, 1.99], p = 0.41), feeding intolerance (RR = 1.14, 95% CI: [0.63, 2.09], p = 0.66), and gastric retention (RR = 0.45, 95% CI: [0.16, 1.30], p = 0.14). Conclusion Our study revealed that the VBF protocol significantly improved calorie and protein delivery in critically ill patients with no additional risk.