Effects of temperature and relative humidity on DNA methylation.

Background: Previous studies have found relationships between DNA methylation and various environmental contaminant exposures. Associations with weather have not been examined. Because temperature and humidity are related to mortality even on non-extreme days, we hypothesized that temperature and relative humidity may affect methylation.

A novel genetic score approach using instruments to investigate interactions between pathways and environment: application to air pollution.

Air pollution has been associated with increased systemic inflammation markers. We developed a new pathway analysis approach to investigate whether gene variants within relevant pathways (oxidative stress, endothelial function, and metal processing) modified the association between particulate air pollution and fibrinogen, C-reactive protein (CRP), intercellular adhesion molecule-1 (ICAM-1), and vascular cell adhesion molecule-1 (VCAM-1). Our study population consisted of 822 elderly participants of the Normative Aging Study (1999-2011).

Extracellular histones mediate the effects of metal-rich air particles on blood coagulation.

Background: Epidemiological studies have shown associations of particulate matter (PM) exposure with hypercoagulability and thrombosis. Extracellular circulating histones have recently been identified as novel mediators of inflammatory and procoagulant responses. The potential roles of extracellular histones in PM-related hypercoagulability have yet not been investigated.

Maternal OGTT glucose levels at 26-30 gestational weeks with offspring growth and development in early infancy.

Aims: We aim to evaluate the association of maternal gestational oral glucose tolerance test (OGTT) glucose concentrations with anthropometry in the offspring from birth to 12 months in Tianjin, China.

Methods: A total of 27,157 pregnant women underwent OGTT during 26-30 weeks gestation, and their children had body weight/length measured from birth to 12 months old.

Results: Maternal OGTT glucose concentrations at 26-30 gestational weeks were positively associated with Z-scores for birth length-for-gestational age and birth weight-for-length.

Epigenome-wide DNA methylation changes with development of arsenic-induced skin lesions in Bangladesh: a case-control follow-up study.

Studies have found an association between aberrant DNA methylation and arsenic-induced skin lesions. However, little is known about DNA methylation changes over time in people who develop arsenic-induced skin lesions. We sought to investigate epigenome-wide changes of DNA methylation in people who developed arsenic-induced skin lesions in a 10-year period.

Cohort profile: project viva.

We established Project Viva to examine prenatal diet and other factors in relation to maternal and child health. We recruited pregnant women at their initial prenatal visit in eastern Massachusetts between 1999 and 2002. Exclusion criteria included multiple gestation, inability to answer questions in English, gestational age ≥22 weeks at recruitment and plans to move away before delivery.

Pessimistic orientation in relation to telomere length in older men: the VA normative aging study.

Background: Recent research suggests pessimistic orientation is associated with shorter leukocyte telomere length (LTL). However, this is the first study to look not only at effects of pessimistic orientation on average LTL at multiple time points, but also at effects on the rate of change in LTL over time.

Methods: Participants were older men from the VA Normative Aging Study (n=490).

Epigenetic influences on associations between air pollutants and lung function in elderly men: the normative aging study.

Background: Few studies have been performed on pulmonary effects of air pollution in the elderly--a vulnerable population with low reserve capacity--and mechanisms and susceptibility factors for potential effects are unclear.

Objectives: We evaluated the lag structure of air pollutant associations with lung function and potential effect modification by DNA methylation (< or ≥ median) at 26 individual CpG sites in nine candidate genes in a well-characterized cohort of elderly men.

Methods: We measured forced vital capacity (FVC), forced expiratory volume in 1 sec (FEV1), and blood DNA methylation one to four times between 1999 and 2009 in 776 men from the Normative Aging Study.

Effect of prenatal arsenic exposure on DNA methylation and leukocyte subpopulations in cord blood.

Prenatal arsenic exposure is associated with increased risk of disease in adulthood. This has led to considerable interest in arsenic's ability to disrupt fetal programming. Many studies report that arsenic exposure alters DNA methylation in whole blood but these studies did not adjust for cell mixture.

Microvesicle-associated microRNA expression is altered upon particulate matter exposure in healthy workers and in A549 cells.

Cardiovascular disease risk has been consistently linked with particulate matter (PM) exposure. Cell-derived microvesicles (MVs) are released into plasma and transfer microRNAs (miRNAs) between tissues. MVs can be produced by the respiratory system in response to proinflammatory triggers, enter the circulatory system and remotely modify gene expression in cardiovascular tissues.

Environmental exposure and mitochondrial epigenetics: study design and analytical challenges.

The environment can influence human health and disease in many harmful ways. Many epidemiological studies have been conducted with the aim of elucidating the association between environmental exposure and human disease at the molecular and pathological levels, and such associations can often be through induced epigenetic changes. One such mechanism for this is through environmental factors increasing oxidative stress in the cell, and this stress can subsequently lead to alterations in DNA molecules.

Air pollution and gene-specific methylation in the Normative Aging Study: association, effect modification, and mediation analysis.

The mechanisms by which air pollution has multiple systemic effects in humans are not fully elucidated, but appear to include inflammation and thrombosis. This study examines whether concentrations of ozone and components of fine particle mass are associated with changes in methylation on tissue factor (F3), interferon gamma (IFN-γ), interleukin 6 (IL-6), toll-like receptor 2 (TLR-2), and intercellular adhesion molecule 1 (ICAM-1). We investigated associations between air pollution exposure and gene-specific methylation in 777 elderly men participating in the Normative Aging Study (1999-2009).

Maternal prepregnancy body mass index and gestational weight gain on pregnancy outcomes.

Objective: The aim of the present study was to evaluate the single and joint associations of maternal prepregnancy body mass index (BMI) and gestational weight gain (GWG) with pregnancy outcomes in Tianjin, China.

Methods: Between June 2009 and May 2011, health care records of 33,973 pregnant women were collected and their children were measured for birth weight and birth length. The independent and joint associations of prepregnancy BMI and GWG based on the Institute of Medicine (IOM) guidelines with the risks of pregnancy and neonatal outcomes were examined by using Logistic Regression.

Blood methylomics in response to arsenic exposure in a low-exposed US population.

Exposure to arsenic (As) has been associated with a number of diseases such as cancers, cardiovascular diseases (CVD), and neurological disorders. To explore the possible underlying epigenetic mechanisms, a nested case-control study was conducted within the Coronary Artery Risk Development in Young Adults (CARDIA) study by randomly selecting 46 non-smoker and non-diabetic White participants with low (N=23) and high (N=23) As exposure based on toenail total As measures at examination year 2. We conducted methylomic profiling of white blood cell (WBC) DNA collected at examination year 15 using the Illumina HumanMethylation450 BeadChip, and performed association tests using multiple linear regression models adjusting for age, sex, and estimated WBC proportions.

Altered methylation in tandem repeat element and elemental component levels in inhalable air particles.

Exposure to particulate matter (PM) has been associated with lung cancer risk in epidemiology investigations. Elemental components of PM have been suggested to have critical roles in PM toxicity, but the molecular mechanisms underlying their association with cancer risks remain poorly understood. DNA methylation has emerged as a promising biomarker for environmental-related diseases, including lung cancer.

Ambient particulate air pollution and microRNAs in elderly men.

Background: Ambient particulate matter (PM) has been associated with mortality and morbidity for cardiovascular disease. MicroRNAs control gene expression at a posttranscriptional level. Altered microRNA expression has been reported in processes related to cardiovascular disease and PM exposure, such as systemic inflammation, endothelial dysfunction, and atherosclerosis.

Aberrant methylation of hypermethylated-in-cancer-1 and exocyclic DNA adducts in tobacco smokers.

Tobacco smoke has been shown to produce both DNA damage and epigenetic alterations. However, the potential role of DNA damage in generating epigenetic changes is largely underinvestigated in human studies. We examined the effects of smoking on the levels of DNA methylation in genes for tumor protein p53, cyclin-dependent kinase inhibitor2A, hypermethylated-in-cancer-1 (HIC1), interleukin-6, Long Interspersed Nuclear Element type1, and Alu retrotransposons in blood of 177 residents in Thailand using bisulfite-PCR andpyrosequencing.

β-2 adrenergic receptor gene methylation is associated with decreased asthma severity in inner-city schoolchildren: asthma and rhinitis.

Background: Genetic variation in the β-2 adrenergic receptor gene (ADRB2) has been implicated in asthma severity and control with conflicting results. Epigenetic variation in the ADRB2 may play an important role in asthma phenotype.

Objective: We aimed to evaluate whether DNA methylation of ADRB2 is associated with asthma phenotypes in inner-city school-aged children.

A-clustering: a novel method for the detection of co-regulated methylation regions, and regions associated with exposure.

Motivation: DNA methylation is a heritable modifiable chemical process that affects gene transcription and is associated with other molecular markers (e.g. gene expression) and biomarkers (e.

Mitochondrial DNA copy number and exposure to polycyclic aromatic hydrocarbons.

Background: Increased mitochondrial DNA copy number (mtDNAcn) is a biologic response to mtDNA damage and dysfunction, predictive of lung cancer risk. Polycyclic aromatic hydrocarbons (PAHs) are established lung carcinogens and may cause mitochondrial toxicity. Whether PAH exposure and PAH-related nuclear DNA (nDNA) genotoxic effects are linked with increased mtDNAcn has never been evaluated.

Evolutionary age of repetitive element subfamilies and sensitivity of DNA methylation to airborne pollutants.

Background: Repetitive elements take up >40% of the human genome and can change distribution through transposition, thus generating subfamilies. Repetitive element DNA methylation has associated with several diseases and environmental exposures, including exposure to airborne pollutants. No systematic analysis has yet been conducted to examine the effects of exposures across different repetitive element subfamilies.

Environmental epigenetics: from novelty to scientific discipline.

Epigenetic phenomena have sparked much interest resulting in an exponential increase in scientific investigation in the last two decades. While growing, the field of environmental epigenetics remains small when compared to other areas of epigenetic inquiry such as cancer research. In this paper, our objective is to describe the status of the field of environmental epigenetics and lay out our vision for its future.