m6A-Related lncRNAs Predict Overall Survival of Patients and Regulate the Tumor Immune Microenvironment in Osteosarcoma.

Background: m6A-related lncRNAs have demonstrated great potential tumor diagnostic and therapeutic targets. The goal of this work was to find m6A-regulated lncRNAs in osteosarcoma patients. Method: The Cancer Genome Atlas (TCGA) database was used to retrieve RNA sequencing and medical information from osteosarcoma sufferers. The Pearson's correlation test was used to identify the m6A-related lncRNAs. A risk model was built using univariate and multivariable Cox regression analysis. Kaplan-Meier survival analysis and receiver functional requirements were used to assess the risk model's performance (ROC). By using the CIBERSORT method, the associations between the relative risks and different immune cell infiltration were investigated. Lastly, the bioactivities of high-risk and low-risk subgroups were investigated using Gene Set Enrichment Analysis (GSEA). Result: A total of 531 m6A-related lncRNAs were obtained from TCGA. Seven lncRNAs have demonstrated prognostic values. A total of 88 OS patients were separated into cluster 1, cluster 2, and cluster 3. The overall survival rate of OS patients in cluster 3 was more favorable than that of those in cluster 1 and cluster 2. The average Stromal score was much higher in cluster 1 than in cluster 2 and cluster 3 (P < 0.05). The expression levels of lncRNAs used in the construction of the risk prediction model in the high-risk group were generally lower than those in the low-risk group. Analysis of patient survival indicated that the survival of the low-risk group was higher than that of the high-risk group (P < 0.0001) and the area under the curve (AUC) of the ROC curve was 0.719. Using the CIBERSORT algorithm, the results revealed that Macrophages M0, Macrophages M2, and T cells CD4 memory resting accounted for a large proportion of immune cell infiltration. By GSEA analysis, our results implied that the high-risk group was mainly involved in unfolded protein response, DNA repair signaling, and epithelial-mesenchymal transition signaling pathway and glycolysis pathway; meanwhile, the low-risk group was mainly involved in estrogen response early and KRAS signaling pathway. Conclusion: Our investigation showed that m6A-related lncRNAs remained tightly connected to the immunological microenvironment of osteosarcoma tumors, potentially influencing carcinogenesis and development. The immune microenvironment and immune-related biochemical pathways can be changed by regulating the transcription of M6A modulators or lncRNAs. In addition, we looked for risk-related signaling of m6A-related lncRNAs in osteosarcomas and built and validated the risk prediction system. The findings of our current analysis will facilitate the assessment of outcomes and the development of immunotherapies for sufferers of osteosarcomas.

Monocyte miRNAs Are Associated With Type 2 Diabetes.

miRNAs are small noncoding RNAs that may contribute to common diseases through epigenetic regulation of gene expression. Little is known regarding the role of miRNAs in type 2 diabetes (T2D). We performed miRNA sequencing and transcriptomic profiling of peripheral monocytes from the longitudinal Multi-Ethnic Study of Atherosclerosis (MESA) (N = 1,154). We examined associations between miRNAs and prevalent impaired fasting glucose and T2D and evaluated the T2D-associated miRNA effect on incident T2D. Of 774 detected miRNAs, 6 (miR-22-3p, miR-33a-5p, miR-181c-5p, miR-92b-3p, miR-222-3p, and miR-944) were associated with prevalent T2D. For five of the six miRNAs (all but miR-222-3p), our findings suggest a dose-response relationship with impaired fasting glucose and T2D. Two of the six miRNAs were associated with incident T2D (miR-92b-3p: hazard ratio [HR] 1.64, P = 1.30E-03; miR-222-3p: HR 1.97, P = 9.10E-03) in the highest versus lowest tertile of expression. Most of the T2D-associated miRNAs were also associated with HDL cholesterol concentrations. The genes targeted by these miRNAs belong to key nodes of a cholesterol metabolism transcriptomic network. Higher levels of miRNA expression expected to increase intracellular cholesterol accumulation in monocytes are linked to an increase in T2D risk.

Association of hip fractures with cardiometabolic-renal risk factors in Southern Chinese patients with type 2 diabetes - the Hong Kong Diabetes Register.

INTRODUCTION: Diabetes and bone health are closely related. We examined the incidence and risk factors of hip fractures in Chinese patients with type 2 diabetes (T2D). MATERIALS AND METHODS: In this prospective cohort, we consecutively enrolled 22,325 adults with T2D above the age of 40 years in the Hong Kong Diabetes Register between 1994 and 2015 with crude hip fracture incidence rate censored in 2017. RESULTS: At baseline, the mean age of this cohort was 60.9 ± 10.5 years (mean duration of diabetes 6 years, 52.4% male). During a mean ± standard deviation (SD) follow-up period of 8.7 ± 5.2 years with 193,553 person-years, 603 patients were hospitalized due to hip fractures with an incidence (95% confidence interval, CI) of 315.1 (290.4-341.3) per 100,000 person-years. On multivariable analysis with competing death risk adjusted, the independent hazard ratios (95% CI) for hip fractures in T2D were 2.01 (1.61-2.51) for female sex, 1.08 (1.07-1.09) for age, 0.93 (0.90-0.95) for body mass index, 1.52 (1.25-1.85) for albuminuria and 1.12 (1.02-1.23) for low density lipoprotein-cholesterol. In men, the 30-day, 1-year and 5-year post-hip fracture mortality rate (95% CI) were 5.8 (2.4-9.1) %, 29.2 (22.3-35.5) % and 65.9 (57.3-72.8) % respectively. The corresponding rates in women were 3.4 (1.6-5.1) %, 18.6 (14.7-22.4) %, and 46.8 (40.9-52.1) %. CONCLUSIONS: Southern Chinese patients with T2D have a high risk of hip fracture associated with suboptimal cardiometabolic-renal risk factors and a high post-fracture mortality rate. The effects of improving modifiable risk factors on bone health warrants further evaluation.

Single-cell analyses identify dysfunctional CD16+ CD8 T cells in smokers.

Tobacco smoke exposure contributes to the global burden of communicable and chronic diseases. To identify immune cells affected by smoking, we use single-cell RNA sequencing on peripheral blood from smokers and nonsmokers. Transcriptomes reveal a subpopulation of FCGR3A (CD16)-expressing Natural Killer (NK)-like CD8 T lymphocytes that increase in smokers. Mass cytometry confirms elevated CD16+ CD8 T cells in smokers. Inferred as highly differentiated by pseudotime analysis, NK-like CD8 T cells express markers characteristic of effector memory re-expressing CD45RA T (TEMRA) cells. Indicative of immune aging, smokers' CD8 T cells are biased toward differentiated cells and smokers have fewer naïve cells than nonsmokers. DNA methylation-based models show that smoking dose is associated with accelerated aging and decreased telomere length, a biomarker of T cell senescence. Immune aging accompanies T cell senescence, which can ultimately lead to impaired immune function. This suggests a role for smoking-induced, senescence-associated immune dysregulation in smoking-mediated pathologies.

Epidemiological characteristics and repeated infection analysis of scrub typhus in Anhui Province from 2008 to 2017 / 中华疾病控制杂志

@# Objective To understand the epidemiological characteristics of scrub typhus in Anhui Province from 2008 to 2017, so as to provide scientific evidence for the development of control strategies and control measures. Methods Descriptive epidemiological methods were used to describe and analyze the cases of scrub typhus in Anhui Province from 2008 to 2017. Results The overall incidence of scrub typhus in Anhui Province showed an upward trend from 2008 to 2017 ( χ2=3 522.49, P<0.001). The highest incidence rate in 2016 was 3.98/100 000. The cases were concentrated from September to November. It was a typical “autumn and winter type” and peaked in October. It had the phenomenon of “high incidence in October”; the cases were mainly concentrated in the age group of 40-79 years old, accounting for 76.64% of the total reported cases. The cumulative number of cases in the 60-69 age group was the largest, and the incidence was mainly farmers. Conclusions In recent years, the incidence of scrub typhus in Anhui Province has shown an upward trend. It is necessary to strengthen the routine monitoring of scrub typhus in key areas and the detection of scrub typhus pathogens, and actively carry out prevention and health education of scrub typhus.

Identification of Smoking-Associated Differentially Methylated Regions Using Reduced Representation Bisulfite Sequencing and Cell type-Specific Enhancer Activation and Gene Expression.

BACKGROUND: Cigarette smoke is a causal factor in cancers and cardiovascular disease. Smoking-associated differentially methylated regions (SM-DMRs) have been observed in disease studies, but the causal link between altered DNA methylation and transcriptional change is obscure. OBJECTIVE: Our objectives were to finely resolve SM-DMRs and to interrogate the mechanistic link between SM-DMRs and altered transcription of enhancer noncoding RNA (eRNA) and mRNA in human circulating monocytes. METHOD: We integrated SM-DMRs identified by reduced representation bisulfite sequencing (RRBS) of circulating CD14+ monocyte DNA collected from two independent human studies [n=38 from Clinical Research Unit (CRU) and n=55 from the Multi-Ethnic Study of Atherosclerosis (MESA), about half of whom were active smokers] with gene expression for protein-coding genes and noncoding RNAs measured by RT-PCR or RNA sequencing. Candidate SM-DMRs were compared with RRBS of purified CD4+ T cells, CD8+ T cells, CD15+ granulocytes, CD19+ B cells, and CD56+ NK cells (n=19 females, CRU). DMRs were validated using pyrosequencing or bisulfite amplicon sequencing in up to 85 CRU volunteers, who also provided saliva DNA. RESULTS: RRBS identified monocyte SM-DMRs frequently located in putative gene regulatory regions. The most significant monocyte DMR occurred at a poised enhancer in the aryl-hydrocarbon receptor repressor gene (AHRR) and it was also detected in both granulocytes and saliva DNA. To our knowledge, we identify for the first time that SM-DMRs in or near AHRR, C5orf55-EXOC-AS, and SASH1 were associated with increased noncoding eRNA as well as mRNA in monocytes. Functionally, the AHRR SM-DMR appeared to up-regulate AHRR mRNA through activating the AHRR enhancer, as suggested by increased eRNA in the monocytes, but not granulocytes, from smokers compared with nonsmokers. CONCLUSIONS: Our findings suggest that AHRR SM-DMR up-regulates AHRR mRNA in a monocyte-specific manner by activating the AHRR enhancer. Cell type-specific activation of enhancers at SM-DMRs may represent a mechanism driving smoking-related disease. https://doi.org/10.1289/EHP2395.

Tobacco exposure-related alterations in DNA methylation and gene expression in human monocytes: the Multi-Ethnic Study of Atherosclerosis (MESA).

Alterations in DNA methylation and gene expression in blood leukocytes are potential biomarkers of harm and mediators of the deleterious effects of tobacco exposure. However, methodological issues, including the use of self-reported smoking status and mixed cell types have made previously identified alterations in DNA methylation and gene expression difficult to interpret. In this study, we examined associations of tobacco exposure with DNA methylation and gene expression, utilizing a biomarker of tobacco exposure (urine cotinine) and CD14+ purified monocyte samples from 934 participants of the community-based Multi-Ethnic Study of Atherosclerosis (MESA). Urine cotinine levels were measured using an immunoassay. DNA methylation and gene expression were measured with microarrays. Multivariate linear regression was used to test for associations adjusting for age, sex, race/ethnicity, education, and study site. Urine cotinine levels were associated with methylation of 176 CpGs [false discovery rate (FDR)<0.01]. Four CpGs not previously identified by studies of non-purified blood samples nominally replicated (P value<0.05) with plasma cotinine-associated methylation in 128 independent monocyte samples. Urine cotinine levels associated with expression of 12 genes (FDR<0.01), including increased expression of P2RY6 (Beta ± standard error = 0.078 ± 0.008, P = 1.99 × 10-22), a gene previously identified to be involved in the release of pro-inflammatory cytokines. No cotinine-associated (FDR<0.01) methylation profiles significantly (FDR<0.01) correlated with cotinine-associated (FDR<0.01) gene expression profiles. In conclusion, our findings i) identify potential monocyte-specific smoking-associated methylation patterns and ii) suggest that alterations in methylation may not be a main mechanism regulating gene expression in monocytes in response to cigarette smoking.

Blood monocyte transcriptome and epigenome analyses reveal loci associated with human atherosclerosis.

Little is known regarding the epigenetic basis of atherosclerosis. Here we present the CD14+ blood monocyte transcriptome and epigenome signatures associated with human atherosclerosis. The transcriptome signature includes transcription coactivator, ARID5B, which is known to form a chromatin derepressor complex with a histone H3K9Me2-specific demethylase and promote adipogenesis and smooth muscle development. ARID5B CpG (cg25953130) methylation is inversely associated with both ARID5B expression and atherosclerosis, consistent with this CpG residing in an ARID5B enhancer region, based on chromatin capture and histone marks data. Mediation analysis supports assumptions that ARID5B expression mediates effects of cg25953130 methylation and several cardiovascular disease risk factors on atherosclerotic burden. In lipopolysaccharide-stimulated human THP1 monocytes, ARID5B knockdown reduced expression of genes involved in atherosclerosis-related inflammatory and lipid metabolism pathways, and inhibited cell migration and phagocytosis. These data suggest that ARID5B expression, possibly regulated by an epigenetically controlled enhancer, promotes atherosclerosis by dysregulating immunometabolism towards a chronic inflammatory phenotype.The molecular mechanisms mediating the impact of environmental factors in atherosclerosis are unclear. Here, the authors examine CD14+ blood monocyte's transcriptome and epigenome signatures to find differential methylation and expression of ARID5B to be associated with human atherosclerosis.

Correction: Distinct Epigenetic Effects of Tobacco Smoking in Whole Blood and among Leukocyte Subtypes.

[This corrects the article DOI: 10.1371/journal.pone.0166486.].

Sequential parenteral and enteral nutrition decreased the the risk of pulmonary infection and upper gastrointestinal bleeding in critical patients with acute ischemic stroke / 肠外与肠内营养

Objective:To study the optimal nutritional support strategy in critical patients with acute ischemic stroke.Methods:50 critical patients with acute ischemic stroke were divided into two groups.One group were started with enteral nutrition alone within 24h after admission,while the other group received sequential parenteral and enteral nutrition.The incidence of pulmonary infection,gastric retention,upper gastrointestinal bleeding,hypoglycemia and hyperglycemia were compared between the two groups.Another endpoint was discharge from ICU at day 20,and it was compared between the two groups using Kaplan-Meier methods.Results:There was no difference between the two groups in the rate of hypoglycemia or hyperglycemia (P ＞ 0.05).The incidences of pulmonary infection,gastric retention,upper gastrointestinal bleeding and diarrhea were lower in the PN+EN group than EN group (P ＜ 0.01).The length of ICU stay was also shorter in the PN+EN group.Conclusion:The strategy of sequential parenteral and enteral nutrition decreased the complication rate related to nutrition support,such as pulmonary infection,gastric retention,upper gastrointestinal bleeding.Also,it shortened the ICU stay in critical patients with acute ischemic stroke.

Distinct Epigenetic Effects of Tobacco Smoking in Whole Blood and among Leukocyte Subtypes.

Tobacco smoke exposure dramatically alters DNA methylation in blood cells and may mediate smoking-associated complex diseases through effects on immune cell function. However, knowledge of smoking effects in specific leukocyte subtypes is limited. To better characterize smoking-associated methylation changes in whole blood and leukocyte subtypes, we used Illumina 450K arrays and Reduced Representation Bisulfite Sequencing (RRBS) to assess genome-wide DNA methylation. Differential methylation analysis in whole blood DNA from 172 smokers and 81 nonsmokers revealed 738 CpGs, including 616 previously unreported CpGs, genome-wide significantly associated with current smoking (p <1.2x10-7, Bonferroni correction). Several CpGs (MTSS1, NKX6-2, BTG2) were associated with smoking duration among heavy smokers (>22 cigarettes/day, n = 86) which might relate to long-term heavy-smoking pathology. In purified leukocyte subtypes from an independent group of 20 smokers and 14 nonsmokers we further examined methylation and gene expression for selected genes among CD14+ monocytes, CD15+ granulocytes, CD19+ B cells, and CD2+ T cells. In 10 smokers and 10 nonsmokers we used RRBS to fine map differential methylation in CD4+ T cells, CD8+ T cells, CD14+, CD15+, CD19+, and CD56+ natural killer cells. Distinct cell-type differences in smoking-associated methylation and gene expression were identified. AHRR (cg05575921), ALPPL2 (cg21566642), GFI1 (cg09935388), IER3 (cg06126421) and F2RL3 (cg03636183) showed a distinct pattern of significant smoking-associated methylation differences across cell types: granulocytes> monocytes>> B cells. In contrast GPR15 (cg19859270) was highly significant in T and B cells and ITGAL (cg09099830) significant only in T cells. Numerous other CpGs displayed distinctive cell-type responses to tobacco smoke exposure that were not apparent in whole blood DNA. Assessing the overlap between these CpG sites and differential methylated regions (DMRs) with RRBS in 6 cell types, we confirmed cell-type specificity in the context of DMRs. We identified new CpGs associated with current smoking, pack-years, duration, and revealed unique profiles of smoking-associated DNA methylation and gene expression among immune cell types, providing potential clues to hematopoietic lineage-specific effects in disease etiology.

A Polymorphic Antioxidant Response Element Links NRF2/sMAF Binding to Enhanced MAPT Expression and Reduced Risk of Parkinsonian Disorders.

The NRF2/sMAF protein complex regulates the oxidative stress response by occupying cis-acting enhancers containing an antioxidant response element (ARE). Integrating genome-wide maps of NRF2/sMAF occupancy with disease-susceptibility loci, we discovered eight polymorphic AREs linked to 14 highly ranked disease-risk SNPs in individuals of European ancestry. Among these SNPs was rs242561, located within a regulatory region of the MAPT gene (encoding microtubule-associated protein Tau). It was consistently occupied by NRF2/sMAF in multiple experiments and its strong-binding allele associated with higher mRNA levels in cell lines and human brain tissue. Induction of MAPT transcription by NRF2 was confirmed using a human neuroblastoma cell line and a Nrf2-deficient mouse model. Most importantly, rs242561 displayed complete linkage disequilibrium with a highly protective allele identified in multiple GWASs of progressive supranuclear palsy, Parkinson's disease, and corticobasal degeneration. These observations suggest a potential role for NRF2/sMAF in tauopathies and a possible role for NRF2 pathway activators in disease prevention.

DNA Methylation of the Aryl Hydrocarbon Receptor Repressor Associations With Cigarette Smoking and Subclinical Atherosclerosis.

BACKGROUND: Tobacco smoke contains numerous agonists of the aryl hydrocarbon receptor (AhR) pathway, and activation of the AhR pathway was shown to promote atherosclerosis in mice. Intriguingly, cigarette smoking is most strongly and robustly associated with DNA modifications to an AhR pathway gene, the AhR repressor (AHRR). We hypothesized that altered AHRR methylation in monocytes, a cell type sensitive to cigarette smoking and involved in atherogenesis, may be a part of the biological link between cigarette smoking and atherosclerosis. METHODS AND RESULTS: DNA methylation profiles of AHRR in monocytes (542 CpG sites ± 150 kb of AHRR, using Illumina 450K array) were integrated with smoking habits and ultrasound-measured carotid plaque scores from 1256 participants of the Multi-Ethnic Study of Atherosclerosis (MESA). Methylation of cg05575921 significantly associated (P=6.1 × 10(-134)) with smoking status (current versus never). Novel associations between cg05575921 methylation and carotid plaque scores (P=3.1 × 10(-10)) were identified, which remained significant in current and former smokers even after adjusting for self-reported smoking habits, urinary cotinine, and well-known cardiovascular disease risk factors. This association replicated in an independent cohort using hepatic DNA (n=141). Functionally, cg05575921 was located in a predicted gene expression regulatory element (enhancer) and had methylation correlated with AHRR mRNA profiles (P=1.4 × 10(-17)) obtained from RNA sequencing conducted on a subset (n=373) of the samples. CONCLUSIONS: These findings suggest that AHRR methylation may be functionally related to AHRR expression in monocytes and represents a potential biomarker of subclinical atherosclerosis in smokers.

Actl6a protects embryonic stem cells from differentiating into primitive endoderm.

Actl6a (actin-like protein 6A, also known as Baf53a or Arp4) is a subunit shared by multiple complexes including esBAF, INO80, and Tip60-p400, whose main components (Brg1, Ino80, and p400, respectively) are crucial for the maintenance of embryonic stem cells (ESCs). However, whether and how Actl6a functions in ESCs has not been investigated. ESCs originate from the epiblast (EPI) that is derived from the inner cell mass (ICM) in blastocysts, which also give rise to primitive endoderm (PrE). The molecular mechanisms for EPI/PrE specification remain unclear. In this study, we provide the first evidence that Actl6a can protect mouse ESCs (mESCs) from differentiating into PrE. While RNAi knockdown of Actl6a, which appeared highly expressed in mESCs and downregulated during differentiation, induced mESCs to differentiate towards the PrE lineage, ectopic expression of Actl6a was able to repress PrE differentiation. Our work also revealed that Actl6a could interact with Nanog and Sox2 and promote Nanog binding to pluripotency genes such as Oct4 and Sox2. Interestingly, cells depleted of p400, but not of Brg1 or Ino80, displayed similar PrE differentiation patterns. Mutant Actl6a with impaired ability to bind Tip60 and p400 failed to block PrE differentiation induced by Actl6a dysfunction. Finally, we showed that Actl6a could target to the promoters of key PrE regulators (e.g., Sall4 and Fgf4), repressing their expression and inhibiting PrE differentiation. Our findings uncover a novel function of Actl6a in mESCs, where it acts as a gatekeeper to prevent mESCs from entering into the PrE lineage through a Yin/Yang regulating pattern.

The effects of metformin on glucolipid metabolic disorders and liver lipid deposition caused by clozapine in rats / 预防医学

Objective To study the effect of metformin on glucolipid metabolic disorders and liver lipid deposition caused by clozapine in rats.Methods From 1 d to 4 d,Clozapine 5 mg·kg -1 ·d -1 was gavaged,and the dose increased to 25 mg·kg -1 ·d -1 from the 5th day.Metformin 100 mg·kg -1 ·d -1 or 400 mg·kg -1 ·d -1 or simvastatin 1 mg· kg -1 ·d -1 was gavaged from the 15th day.The total period of dosing was 8 weeks.Body mass,fasting blood sugar (FBS) and postprandial 2 hours blood glucose (2hPBG)were measured at baseline,3 d,1 week,2 weeks,4 weeks,6 weeks and 8 weeks.At the end of the 8th week,serum cholesterol (TC),triglyceride (TG),low density lipoprotein (LDL -C), high density lipoprotein (HDL -C),fructosamine (FA)and insulin (IRS)were measured and liver HE staining was done.Results There were no significant differences of the measured indexes between control group and metformin group at the all test points.By the end of the 6th and 8th week,compared with control group,the body mass,FBS,2hPBG,IRS, FA,TC,TG and LDL -C were significantly increased in clozapine group (P <0.05 ),while HDL -C decreased in clozapine group (P <0.05).Compared with clozapine group,body mass,FBS,2hPBG,IRS,FA,TC,TG and LDL -C were significantly decreased by metformin or simvastatin administration (P <0.05),while HDL -C increased(P <0.05).Rat liver cells in clozapine group were not neat around the small blood vessels;there were more white fat cells and hepatocellular lipid calm far away from the blood vessels.However,in other groups,there were moderate white fat cells, and there were not much hepatocellular lipid calm far away from the blood vessels.Conclusion Metformin could effectively prevent and treat weight gain,glucolipid metabolic disorder and liver lipid deposition caused by clozapine.

Comparison of Piroxicam Pharmacokinetics and Anti-Inflammatory Effect in Rats after Intra-Articular and Intramuscular Administration

This study evaluated the pharmacokinetic profile and therapeutic efficacy of piroxicam (PX), a long acting non-steroidal anti-inflammatory drug for the treatment of arthritis, following intra-articular (IA) injection in comparison to the pharmacokinetic profile and therapeutic efficacy of PX after intramuscular (IM) injection. In the pharmacokinetic study in rats, systemic exposure and pharmacokinetic parameters of PX after a single IA dose were compared with systemic exposure and pharmacokinetic parameters of PX after administration of the same dose IM (0.6 mg/kg). The anti-inflammatory and analgesic effects of IA PX were evaluated simultaneously in a monoiodoacetate-induced osteoarthritis rat model. The plasma PX concentration rapidly rose following IA injection, and it was comparable to the plasma PX concentration following IM injection, suggesting the rapid efflux of the drug molecule from the joint cavity. However, in the efficacy study, the IA PX administration significantly reduced the knee swelling by reducing the level of prostaglandin E2 in the joint, compared to that following administration of IA vehicle and after administration of the IM PX dose. In addition, we found that the anti-inflammatory and anti-nociceptive efficacies of IA PX were synergistically increased upon co-treatment with hyaluronic acid (HA), a potent agent for the treatment of osteoarthritis, at the weight ratio of 1:1 or 1:2, and these effects were more pronounced than those following administration of HA or PX alone. In conclusion, this study demonstrated the efficacy of the IA use of PX alone and/or in combination with HA in osteoarthritis.

Ten-eleven translocation 1 (Tet1) is regulated by O-linked N-acetylglucosamine transferase (Ogt) for target gene repression in mouse embryonic stem cells.

As a member of the Tet (Ten-eleven translocation) family proteins that can convert 5-methylcytosine (5mC) to 5-hydroxylmethylcytosine (5hmC), Tet1 has been implicated in regulating global DNA demethylation and gene expression. Tet1 is highly expressed in embryonic stem (ES) cells and appears primarily to repress developmental genes for maintaining pluripotency. To understand how Tet1 may regulate gene expression, we conducted large scale immunoprecipitation followed by mass spectrometry of endogenous Tet1 in mouse ES cells. We found that Tet1 could interact with multiple chromatin regulators, including Sin3A and NuRD complexes. In addition, we showed that Tet1 could also interact with the O-GlcNAc transferase (Ogt) and be O-GlcNAcylated. Depletion of Ogt led to reduced Tet1 and 5hmC levels on Tet1-target genes, whereas ectopic expression of wild-type but not enzymatically inactive Ogt increased Tet1 levels. Mutation of the putative O-GlcNAcylation site on Tet1 led to decreased O-GlcNAcylation and level of the Tet1 protein. Our results suggest that O-GlcNAcylation can positively regulate Tet1 protein concentration and indicate that Tet1-mediated 5hmC modification and target repression is controlled by Ogt.

Kdm2b maintains murine embryonic stem cell status by recruiting PRC1 complex to CpG islands of developmental genes.

Polycomb group (PcG) proteins play important roles in repressing lineage-specific genes and maintaining the undifferentiated state of mouse embryonic stem cells (mESCs). However, how PcG proteins are recruited to their target genes is largely unknown. Here, we show that the H3K36-specific histone demethylase Kdm2b is highly expressed in mESCs and regulated by the pluripotent factors Oct4 and Sox2 directly. Depletion of Kdm2b in mESCs causes de-repression of lineage-specific genes and induces early differentiation. The function of Kdm2b depends on its CxxC-ZF domain, which mediates its genome-wide binding to CpG islands (CGIs). Kdm2b interacts with the core components of polycomb repressive complex 1 (PRC1) and recruits the complex to the CGIs of early lineage-specific genes. Thus, our study not only reveals an Oct4-Sox2-Kdm2b-PRC1-CGI regulatory axis and its function in maintaining the undifferentiated state of mESCs, but also demonstrates a critical function of Kdm2b in recruiting PRC1 to the CGIs of lineage-specific genes to repress their expression.

Telomeres-structure, function, and regulation.

In mammals, maintenance of the linear chromosome ends (or telomeres) involves faithful replication of genetic materials and protection against DNA damage signals, to ensure genome stability and integrity. These tasks are carried out by the telomerase holoenzyme and a unique nucleoprotein structure in which an array of telomere-associated proteins bind to telomeric DNA to form special protein/DNA complexes. The telomerase complex, which is comprised of telomeric reverse transcriptase (TERT), telomeric RNA component (TERC), and other assistant factors, is responsible for adding telomeric repeats to the ends of chromosomes. Without proper telomere maintenance, telomere length will shorten with successive round of DNA replication due to the so-called end replication problem. Aberrant regulation of telomeric proteins and/or telomerase may lead to abnormalities that can result in diseases such as dyskeratosis congenita (DC) and cancers. Understanding the mechanisms that regulate telomere homeostasis and the factors that contribute to telomere dysfunction should aid us in developing diagnostic and therapeutic tools for these diseases.

The trithorax group protein Ash2l is essential for pluripotency and maintaining open chromatin in embryonic stem cells.

Embryonic stem (ES) cells exhibit general characteristics of open chromatin, a state that may be necessary for ES cells to efficiently self-renew while remaining poised for differentiation. Histone H3K4 and H3K9 trimethylation associate as a general rule, with open and silenced chromatin, respectively, for ES cell pluripotency maintenance. However, how histone modifications are regulated to maintain open chromatin in ES cells remains largely unknown. Here, we demonstrate that trithorax protein Ash2l, homologue of the Drosophila Ash2 (absent, small, homeotic-2) protein, is a key regulator of open chromatin in ES cells. Consistent with Ash2l being a core subunit of mixed lineage leukemia methyltransferase complex, RNAi knockdown of Ash2l was sufficient to reduce H3K4 methylation levels and drive ES cells to a silenced chromatin state with high H3K9 trimethylation. Genome-wide ChIP-seq analysis indicated that Ash2l is recruited to target loci through two distinct modes and enriched at a family of genes implicated in open chromatin regulation, including chromatin remodeler Cdh7, transcription factor c-Myc, and H3K9 demethylase Kdm4c. Our results underscore the importance of Ash2l in open chromatin regulation and provide insight into how the open chromatin landscape is maintained in ES cells.