Incorporation of an Epigenetic Evaluation into Safety Assessment: What we First Need to Know

Toxicoepigenetics for Risk Assessment: Bridging the Gap Between Basic and Regulatory Science

Toxicoepigenetics examines the health effects of environmental exposure associated with, or mediated by, changes in the epigenome. Despite high expectations, toxicoepigenomic data and methods have yet to become significantly utilized in chemical risk assessment. This article draws on a social science framework to highlight hitherto overlooked structural barriers to the incorporation of toxicoepigenetics in risk assessment and to propose ways forward. The present barriers stem not only from the lack of maturity of the field but also from differences in constraints and standards between the data produced by toxicoepigenetics and the regulatory science data that risk assessment processes require. Criteria and strategies that frame the validation of knowledge used for regulatory purposes limit the application of basic research in toxicoepigenetics toward risk assessment. First, the need in regulatory toxicology for standardized methods that form a consensus between regulatory agencies, basic research, and the industry conflicts with the wealth of heterogeneous data in toxicoepigenetics. Second, molecular epigenetic data do not readily translate into typical toxicological endpoints. Third, toxicoepigenetics investigates new forms of toxicity, in particular low-dose and long-term effects, that do not align well with the traditional framework of regulatory toxicology. We propose that increasing the usefulness of epigenetic data for risk assessment will require deliberate efforts on the part of the toxicoepigenetics community in 4 areas: fostering the understanding of epigenetics among risk assessors, developing knowledge infrastructure to demonstrate applicability, facilitating the normalization and exchange of data, and opening the field to other stakeholders.

Epigenetic profiling to environmental stressors in model and non-model organisms: Ecotoxicology perspective

Epigenetics, potentially heritable changes in genome function that occur without alterations to DNA sequence, is an important but understudied component of ecotoxicology studies. A wide spectrum of environmental challenge, such as temperature, stress, diet, toxic chemicals, are known to impact on epigenetic regulatory mechanisms. Although the role of epigenetic factors in certain biological processes, such as tumourigenesis, has been heavily investigated, in ecotoxicology field, epigenetics still have attracted little attention. In ecotoxicology, potential role of epigenetics in multi- and transgenerational phenomenon to environmental stressors needs to be unrevealed. Natural variation in the epigenetic profiles of species in responses to environmental stressors, nature of dose-response relationships for epigenetic effects, and how to incorporate this information into ecological risk assessment should also require attentions. In this review, we presented the available information on epigenetics in ecotoxicological context. For this, we have conducted a systemic review on epigenetic profiling in response to environmental stressors, mostly chemical exposure, in model organisms, as well as, in ecotoxicologically relevant wildlife species.