Association of Childhood Chronic Physical Aggression with a DNA Methylation Signature in Adult Human T Cells

Background

Chronic physical aggression (CPA) is characterized by frequent use of physical aggression from early childhood to adolescence. Observed in approximately 5% of males, CPA is associated with early childhood adverse environments and long-term negative consequences. Alterations in DNA methylation, a covalent modification of DNA that regulates genome function, have been associated with early childhood adversity.

Aims

To test the hypothesis that a trajectory of chronic physical aggression during childhood is associated with a distinct DNA methylation profile during adulthood.

Methods

We analyzed genome-wide promoter DNA methylation profiles of T cells from two groups of adult males assessed annually for frequency of physical aggression between 6 and 15 years of age: a group with CPA and a control group. Methylation profiles covering the promoter regions of 20 000 genes and 400 microRNAs were generated using MeDIP followed by hybridization to microarrays.

Results

In total, 448 distinct gene promoters were differentially methylated in CPA. Functionally, many of these genes have previously been shown to play a role in aggression and were enriched in biological pathways affected by behavior. Their locations in the genome tended to form clusters spanning millions of bases in the genome.

Conclusions

This study provides evidence of clustered and genome-wide variation in promoter DNA methylation in young adults that associates with a history of chronic physical aggression from 6 to 15 years of age. However, longitudinal studies of methylation during early childhood will be necessary to determine if and how this methylation variation in T cells DNA plays a role in early development of chronic physical aggression.     

Childhood Chronic Physical Aggression Associates with Adult Cytokine Levels in Plasma

Background

An increasing number of animal and human studies are indicating that inflammation is associated with behavioral disorders including aggression. This study investigates the association between chronic physical aggression during childhood and plasma cytokine levels in early adulthood.

Methodology/Principal Findings

Two longitudinal studies were used to select males on a chronic physical aggression trajectory from childhood to adolescence (n = 7) and a control group from the same background (n = 25). Physical aggression was assessed yearly by teachers from childhood to adolescence and plasma levels of 10 inflammatory cytokines were assessed at age 26 and 28 years. Compared to the control group, males on a chronic physical aggression trajectory from childhood to adolescence had consistently lower plasma levels of five cytokines: lower pro-inflammatory interleukins IL-1α (T(28.7) = 3.48, P = 0.002) and IL-6 (T(26.9) = 3.76, P = 0.001), lower anti-inflammatory interleukin IL-4 (T(27.1) = 4.91, P = 0.00004) and IL-10 (T(29.8) = 2.84, P = 0.008) and lower chemokine IL-8 (T(26) = 3.69, P = 0.001). The plasma levels of four cytokines accurately predicted aggressive and control group membership for all subjects.

Conclusions/Significance

Physical aggression of boys during childhood is a strong predictor of reduced plasma levels of cytokines in early adulthood. The causal and physiological relations underlying this association should be further investigated since animal data suggest that some cytokines such as IL-6 and IL-1β play a causal role in aggression.     

Ranch Women and Men on Both Sides of the Border

Hell on Horses and Women . Alice Marriott
Charrería Mexicana: An Equestrian Folk Tradition . Kathleen Mullen Sands     

Aberrant DNA Methylation in ES Cells

Both mouse and human embryonic stem cells can be differentiated in vitro to produce a variety of somatic cell types. Using a new developmental tracing approach, we show that these cells are subject to massive aberrant CpG island de novo methylation that is exacerbated by differentiation in vitro. Bioinformatics analysis indicates that there are two distinct forms of abnormal de novo methylation, global as opposed to targeted, and in each case the resulting pattern is determined by molecular rules correlated with local pre-existing histone modification profiles. Since much of the abnormal methylation generated in vitro appears to be stably maintained, this modification may inhibit normal differentiation and could predispose to cancer if cells are used for replacement therapy. Excess CpG island methylation is also observed in normal placenta, suggesting that this process may be governed by an inherent program.     

Comprehensive DNA Methylation Analysis Reveals a Common Ten-Gene Methylation Signature in Colorectal Adenomas and Carcinomas

Microarray analysis of promoter hypermethylation provides insight into the role and extent of DNA methylation in the development of colorectal cancer (CRC) and may be co-monitored with the appearance of driver mutations. Colonic biopsy samples were obtained endoscopically from 10 normal, 23 adenoma (17 low-grade (LGD) and 6 high-grade dysplasia (HGD)), and 8 ulcerative colitis (UC) patients (4 active and 4 inactive). CRC samples were obtained from 24 patients (17 primary, 7 metastatic (MCRC)), 7 of them with synchronous LGD. Field effects were analyzed in tissues 1 cm (n = 5) and 10 cm (n = 5) from the margin of CRC. Tissue materials were studied for DNA methylation status using a 96 gene panel and for KRAS and BRAF mutations. Expression levels were assayed using whole genomic mRNA arrays. SFRP1 was further examined by immunohistochemistry. HT29 cells were treated with 5-aza-2’ deoxycytidine to analyze the reversal possibility of DNA methylation. More than 85% of tumor samples showed hypermethylation in 10 genes (SFRP1, SST, BNC1, MAL, SLIT2, SFRP2, SLIT3, ALDH1A3, TMEFF2, WIF1), whereas the frequency of examined mutations were below 25%. These genes distinguished precancerous and cancerous lesions from inflamed and healthy tissue. The mRNA alterations that might be caused by systematic methylation could be partly reversed by demethylation treatment. Systematic changes in methylation patterns were observed early in CRC carcinogenesis, occuring in precursor lesions and CRC. Thus we conclude that DNA hypermethylation is an early and systematic event in colorectal carcinogenesis, and it could be potentially reversed by systematic demethylation therapy, but it would need more in vitro and in vivo experiments to support this theory.     

DNA甲基化修饰与干细胞分化

干细胞自我更新及分化潜能一方面是内源性转录因子相互协调控制的结果,另一方面表观遗传修饰也起着重要的作用。该文综述了DNA甲基化修饰的机理、哺乳动物DNA甲基化的特点以及干细胞分化的DNA甲基化修饰。     

Curcumin Modulates DNA Methylation in Colorectal Cancer Cells

Aim

Recent evidence suggests that several dietary polyphenols may exert their chemopreventive effect through epigenetic modifications. Curcumin is one of the most widely studied dietary chemopreventive agents for colon cancer prevention, however, its effects on epigenetic alterations, particularly DNA methylation, remain unclear. Using systematic genome-wide approaches, we aimed to elucidate the effect of curcumin on DNA methylation alterations in colorectal cancer cells.

Materials and Methods

To evaluate the effect of curcumin on DNA methylation, three CRC cell lines, HCT116, HT29 and RKO, were treated with curcumin. 5-aza-2′-deoxycytidine (5-aza-CdR) and trichostatin A treated cells were used as positive and negative controls for DNA methylation changes, respectively. Methylation status of LINE-1 repeat elements, DNA promoter methylation microarrays and gene expression arrays were used to assess global methylation and gene expression changes. Validation was performed using independent microarrays, quantitative bisulfite pyrosequencing, and qPCR.

Results

As expected, genome-wide methylation microarrays revealed significant DNA hypomethylation in 5-aza-CdR-treated cells (mean β-values of 0.12), however, non-significant changes in mean β-values were observed in curcumin-treated cells. In comparison to mock-treated cells, curcumin-induced DNA methylation alterations occurred in a time-dependent manner. In contrast to the generalized, non-specific global hypomethylation observed with 5-aza-CdR, curcumin treatment resulted in methylation changes at selected, partially-methylated loci, instead of fully-methylated CpG sites. DNA methylation alterations were supported by corresponding changes in gene expression at both up- and down-regulated genes in various CRC cell lines.

Conclusions

Our data provide previously unrecognized evidence for curcumin-mediated DNA methylation alterations as a potential mechanism of colon cancer chemoprevention. In contrast to non-specific global hypomethylation induced by 5-aza-CdR, curcumin-induced methylation changes occurred only in a subset of partially-methylated genes, which provides additional mechanistic insights into the potent chemopreventive effect of this dietary nutraceutical.     

Physical Frailty and Body Composition in Obese Elderly Men and Women

Objective: To evaluate the prevalence of frailty and interrelationships among body composition, physical function, and quality of life in community‐dwelling obese elderly (OE) persons. Research Methods and Procedures: Fifty‐two OE, 52 nonobese frail, and 52 nonobese nonfrail subjects, matched for age and sex, were studied. Subjective and objective measures of functional status were evaluated by using the physical performance test, exercise stress test, lower extremity (LE) strength, gait speed, static and dynamic balance, functional status questionnaires, and health‐related quality‐of‐life questionnaire (Medical Outcomes Short Form). Body composition was evaluated by using DXA, and muscle quality was evaluated by determining the ratio of LE strength to LE lean mass. Results: Among OE subjects, 96% met our standard criteria for mild to moderate frailty. Compared with the nonobese nonfrail group, the OE and nonobese frail groups had lower and similar scores in physical performance test, peak aerobic power, and functional status questionnaire, and exhibited similar impairments in strength, walking speed, balance, and health‐related quality of life. Although absolute fat‐free mass (FFM) was greater, the percentage body weight as FFM and muscle quality was lower in the OE group than in the other two groups. Discussion: Physical frailty, which predisposes to loss of independence, is common in community‐living OE men and women. Physical frailty in OE subjects was associated with low percentage FFM, poor muscle quality, and decreased quality of life. These findings suggest that weight loss therapy may be particularly important in OE persons to improve physical function, in addition to improving the medical complications associated with obesity.     

A Mouse Strain Defective in Both T Cells and NK Cells Has Enhanced Sensitivity to Tumor Induction by Plasmid DNA Expressing Both Activated H-Ras and c-Myc

As part of safety studies to evaluate the risk of residual cellular DNA in vaccines manufactured in tumorigenic cells, we have been developing in vivo assays to detect and quantify the oncogenic activity of DNA. We generated a plasmid expressing both an activated human H-ras gene and murine c-myc gene and showed that 1 µg of this plasmid, pMSV-T24-H-ras/MSV-c-myc, was capable of inducing tumors in newborn NIH Swiss mice. However, to be able to detect the oncogenicity of dominant activated oncogenes in cellular DNA, a more sensitive system was needed. In this paper, we demonstrate that the newborn CD3 epsilon transgenic mouse, which is defective in both T-cell and NK-cell functions, can detect the oncogenic activity of 25 ng of the circular form of pMSV-T24-H-ras/MSV-c-myc. When this plasmid was inoculated as linear DNA, amounts of DNA as low as 800 pg were capable of inducing tumors. Animals were found that had multiple tumors, and these tumors were independent and likely clonal. These results demonstrate that the newborn CD3 epsilon mouse is highly sensitive for the detection of oncogenic activity of DNA. To determine whether it can detect the oncogenic activity of cellular DNA derived from four human tumor-cell lines (HeLa, A549, HT-1080, and CEM), DNA (100 µg) was inoculated into newborn CD3 epsilon mice both in the presence of 1 µg of linear pMSV-T24-H-ras/MSV-c-myc as positive control and in its absence. While tumors were induced in 100% of mice with the positive-control plasmid, no tumors were induced in mice receiving any of the tumor DNAs alone. These results demonstrate that detection of oncogenes in cellular DNA derived from four human tumor-derived cell lines in this mouse system was not possible; the results also show the importance of including a positive-control plasmid to detect inhibitory effects of the cellular DNA.     

The Influence of DNA Methylation on Bone Cells

DNA methylation in eukaryotes invokes heritable alterations of the of the cytosine base in DNA without changing the underlying genomic DNA sequence. DNA methylation may be modified by environmental exposures as well as gene polymorphisms and may be a mechanistic link between environmental risk factors and the development of disease. In this review, we consider the role of DNA methylation in bone cells (osteoclasts/osteoblasts/osteocytes) and their progenitors with special focus on in vitro and ex vivo analyses. The number of studies on DNA methylation in bone cells is still somewhat limited, nevertheless it is getting increasingly clear that this type of the epigenetic changes is a critical regulator of gene expression. DNA methylation is necessary for proper development and function of bone cells and is accompanied by disease characteristic functional alterations as presently reviewed including postmenopausal osteoporosis and mechanical strain.     

Association of Physical Activity and Visceral Adipose Tissue in Older Women and Men

Objective: Physical inactivity, abdominal fat, and age are known risk factors for diabetes, cardiovascular disease, and certain cancers. Previous evidence supports an inverse relationship between physical activity (PA) and abdominal fat estimated by waist circumference. However, few investigations used computed tomography (CAT) scanning for precise measures of abdominal fat. Research Methods and Procedures: Sixty-five female and 106 male (age, 64.5 ± 5.2 years) participants in the Prostate, Lung, Colon and Ovarian Cancer Screening Trial underwent a cross-sectional L4–L5 CAT scan to differentiate visceral adipose tissue (VAT). Subjects were also interviewed by phone to determine PA and physical difficulties (PD). Results: Women had lower VAT (170 ± 84 vs. 205 ± 95 cm², p = 0.014), lower VAT/total fat (29.9 ± 7.2% vs. 42.6 ± 10.2%, p < 0.001), and higher total fat (596 ± 385 vs. 482 ± 183 cm², p = 0.010) than men. PA was inversely correlated to VAT (r = −0.164, p = 0.034) and total fat (r = −0.231, p = 0.003) in men and women. Those who reported a PD had higher VAT (249 vs. 180 cm², p < 0.001) and total fat (652 vs. 500 cm², p = 0.008). Multiple regression analysis indicated total PA and PD were independently associated to VAT and total fat. Discussion: This investigation suggests a beneficial effect of PA and a negative influence of PD on abdominal fat accumulation. Although the cross-sectional design limits cause-effect designations, these results are consistent with other studies showing PA/abdominal fat relation.     

Pre-Diagnostic Leukocyte Genomic DNA Methylation and the Risk of Colorectal Cancer in Women

Background

Abnormal one-carbon metabolism may lead to general genomic (global) hypomethylation, which may predispose an individual to the development of colorectal neoplasia.

Methods

We evaluated the association between pre-diagnostic leukocyte genomic DNA methylation level and the risk of colorectal cancer in a nested case-control study of 358 colorectal cancer cases and 661 matched controls within the all-female cohort of the Nurses’ Health Study (NHS). Among control subjects, we further examined major plasma components in the one-carbon metabolism pathway in relation to genomic DNA methylation level. Liquid chromatography/tandem mass spectrometry was used to examine leukocyte genomic DNA methylation level. We calculated odds ratios (ORs) and 95% confidence intervals (95% CIs) using logistic regression.

Results

Overall genomic DNA methylation level was not associated with the risk of colorectal cancer (p for trend, 0.45). Compared with women in the lowest quintile of methylation, the multivariate OR of colorectal cancer risk was 1.32 (95% CI, 0.82–2.13) for those in the highest quintile. We did not find significant associations between major plasma components of one-carbon metabolism or risk factors for colorectal cancer and genomic DNA methylation level (all p for trend >0.05). Also, neither one-carbon metabolism-related plasma components nor well-known risk factors for colorectal cancer modified the association between genomic DNA methylation level and the risk of colorectal cancer (all p for interaction >0.05).

Conclusions

We found no evidence that hypomethylation of leukocyte genomic DNA increases risk of colorectal cancer among women. Additional studies are needed to investigate the association between pre-diagnostic genomic DNA methylation level and colorectal cancer risk among diverse populations.     

DNA甲基化作用与鼠肝细胞的老化

本文比较了不同年龄的鼠肝ＤＮＡ甲基化酶活力及ＤＮＡ甲基化水平,发现它们均与鼠龄呈反相关。又以不同年龄的鼠肝ＤＮＡ为模板,检验了其体外转录活力,发现其与鼠龄呈正相关。     

Identification of Global DNA Methylation Signatures in Glioblastoma-Derived Cancer Stem Cells

Glioblastoma(GBM)is the most common and most aggressive primary brain tumor in adults.The existence of a small population of stem-like tumor cells that efficiently propagate tumors and resist cytotoxic therapy is one proposed mechanism leading to the resilient behavior of tumor cells and poor prognosis.In this study,we performed an in-depth analysis of the DNA methylation landscape in GBMderived cancer stem cells(GSCs).Parallel comparisons of primary tumors and GSC lines derived from these tumors with normal controls(a neural stem cell(NSC)line and normal brain tissue)identified groups of hyper- and hypomethylated genes that display a trend of either increasing or decreasing methylation levels in the order of controls,primary GBMs,and their counterpart GSC lines,respectively.Interestingly,concurrent promoter hypermethylation and gene body hypomethylation were observed in a subset of genes including MGMT,AJAP1 and PTPRN2.These unique DNA methylation signatures were also found in primary GBM-derived xenograft tumors indicating that they are not tissue culture-related epigenetic changes.Integration of GSC-specific epigenetic signatures with gene expression analysis further identified candidate tumor suppressor genes that are frequently down-regulated in GBMs such as SPINT2,NEFM and PENK.Forced re-expression of SPINT2 reduced glioma cell proliferative capacity,anchorage independent growth,cell motility,and tumor sphere formation in vitro.The results from this study demonstrate that GSCs possess unique epigenetic signatures that may play important roles in the pathogenesis of GBM.