Environmental chemical exposures and human epigenetics

Abstract

Every year more than 13 million deaths worldwide are due to environmental pollutants, and approximately 24% of diseases are caused by environmental exposures that might be averted through preventive measures. Rapidly growing evidence has linked environmental pollutants with epigenetic variations, including changes in DNA methylation, histone modifications and microRNAs. Environ mental chemicals and epigenetic changes All of these mechanisms are likely to play important roles in disease aetiology, and their modifications due to environmental pollutants might provide further understanding of disease aetiology, as well as biomarkers reflecting exposures to environmental pollutants and/or predicting the risk of future disease. We summarize the findings on epigenetic alterations related to environmental chemical exposures, and propose mechanisms of action by means of which the exposures may cause such epigenetic changes. We discuss opportunities, challenges and future directions for future epidemiology research in environmental epigenomics. Future investigations are needed to solve methodological and practical challenges, including uncertainties about stability over time of epigenomic changes induced by the environment, tissue specificity of epigenetic alterations, validation of laboratory methods, and adaptation of bioinformatic and biostatistical methods to high-throughput epigenomics. In addition, there are numerous reports of epigenetic modifications arising following exposure to environmental toxicants, but most have not been directly linked to disease endpoints. To complete our discussion, we also briefly summarize the diseases that have been linked to environmental chemicals-related epigenetic changes.

In silico docking of methyl isocyanate (MIC) and its hydrolytic product (1, 3-dimethylurea) shows significant interaction with DNA Methyltransferase 1 suggests cancer risk in Bhopal-Gas-Tragedy survivors

“…In agreement to our results, several studies proved that the global hypomethylation is due to many environmental and agricultural chemicals (Hou et al, 2011) have plausible role in cancer etiology. Interestingly, recent docking studies conducted by Shrivastava et al (2010;2013) and Tripathi et al (2015) also demonstrated a comprehensive understanding of MIC with different immunoproteins against Tuberculosis.…”

“…There is increasing evidence that exposure to toxic chemicals primarily affect the epigenome leading to the alteration of normal epigenetic process (Hou et al, 2011), In humans, chemically-induced epigenetic alterations has been reported to play an important role in cancer development and progression (Fraga et al, 2005;Baccarelli and Bollati, 2009;Shrivastava et al, 2013). Methyl isocyanate (MIC) is a toxic chemical used as an intermediate in the production of carbamate pesticides (HSFS, 2002;Senthilkumar et al, 2011;2012;2013).…”

Promoter Hypermethylation Profile of Tumour Suppressor Genes in Oral Leukoplakia and Oral Squamous Cell Carcinoma

“…The significance of environmental contaminants such as heavy metals have known to be related with multiple diseases, such as cancer, cardiovascular diseases, neurological disorders and autoimmune diseases [13]. Metal ions induce reactive oxygen species (ROS), and thus, lead to the generation of free radicals [14,15].…”

Emerging Roles of Cadmium and Heme Oxygenase in Type-2 Diabetes and Cancer Susceptibility

“…Evidence is accumulating to link epigenetic alterations (DNA methylation, histone modification and micro RNA) with carcinogenicity of a large group of toxicants, including cadmium, that lack an ability to cause gene mutation (Huang et al 2008;Hou et al 2012;Stein 2012). Abnormal methylation or one-carbon metabolism has emerged as one of the potential mechanism that could underlie cadmium epigenetic effects.…”

“…Environmental exposure constitutes 70 to 90% of the risks of developing chronic diseases such as adult-onset type-2 diabetes and cancer (Rappaport and Smith 2010;Hou et al 2012;Stein 2012). Suspected causes of the current epidemic of type-2 diabetes include a wide range of chemicals of environmental origin (Patel et al 2010;Thayer et al 2012).…”