Environmental epigenetics: from novelty to scientific discipline

Abstract

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. While environmental epigenetic studies represent fewer than 5% of all epigenetic publications, the National Institute of Environmental Health Sciences ranks second in proportion of dollars spent on epigenetics of all NIH Institutes. Such investment highlights the hypothesis that epigenetic marks are modified by environmental exposures and the hope that interventions targeted at epigenetic mechanisms may ultimately lead to improved health outcomes. The road to achieve this vision will require: (1) attention to tissue specificity; (2) focused interventional studies; (3) collaboration among cohorts; (4) inclusion of environmental exposures in new large-scale epigenomic studies; and (5) understanding of multiple mechanisms beyond DNA methylation and histone modifications. The investment in environmental epigenetic inquiry will lead to great rewards if we can understand the biology of how phenotype results from environmental stimuli and genetic code. Understanding the epigenetic implications of our actions and exposures may benefit generations to come.

Keywords: DNA methylation; Epigenetics; environmental health; histone modifications; microRNA.

Figure 1. Number of epigenetica and environmental epigeneticb publications since 1990

^aPubmed Search terms: Epigenesis, Genetic"[Mesh] or "DNA methylation"[mesh] or "microRNAs"[mesh] or "histone modification" or epigenetic;^b "Air Pollutants"[Mesh] OR "Water Pollutants, Radioactive"[Mesh] OR "Soil Pollutants, Radioactive"[Mesh] OR "Air Pollutants, Radioactive"[Mesh] OR "Water Pollutants, Chemical"[Mesh] OR "Water Pollutants"[Mesh] OR "Soil Pollutants"[Mesh] OR "Radioactive Pollutants"[Mesh] OR "Environmental Pollutants"[Mesh] OR "Particulate Matter"[Mesh] OR "Water Pollution, Chemical"[Mesh]) OR "Radon"[Mesh] OR "Polychlorinated Biphenyls"[Mesh] OR "Polybrominated Biphenyls"[Mesh] OR "Toxic Actions"[Mesh] OR "Environmental Exposure"[Mesh] OR "Air Pollution"[Mesh] OR "Enviroment"[Mesh] and prior search

Figure 2. Percentage of Institute/Center Total Costs for FY 2012 Used for Epigenetic Studiesa Overall, and by Mechanism (limited to I/Cs spending >3% of their budgets on epigenetics)

^aData from NIH RePORTER accessed 10/26/12, search terms: “DNA methylation” or “histone modification” or “microRNA”, Epigenetic Studies” is not the sum of the others because more than one mechanism are included in some projects.