Environmentally Induced Epigenetic Plasticity in Development: Epigenetic Toxicity and Epigenetic Adaptation

Abstract

Purpose of Review Epigenetic processes represent important mechanisms underlying developmental plasticity in response to environmental exposures. The current review discusses three classes of environmentally-induced epigenetic changes reflecting two aspects of that plasticity, toxicity effects as well as adaptation in the process of development. Recent findings Due to innate resilience, epigenetic changes caused by environmental exposures may not always lead impairments but may allow the organisms to achieve positive developmental outcomes through appropriate adaptation and a buffering response. Thus, some epigenetic adaptive responses to an immediate stimulus or exposure early in life would be expected to have a survival advantage but these same responses may also result in adverse developmental outcomes as they persists into later life stage. Although accumulating literature has identified environmentally induced epigenetic changes and linked them to health outcomes, we currently face challenges in the interpretation of the functional impact of their epigenetic plasticity. Summary Current environmental epigenetic research suggest that epigenetic processes may serve as a mechanism for resilience, and that they can be considered in terms of their impact on toxicity as a negative outcome, but also on adaptation for improved survival or health. This review encourages epigenetic environmental studies to move deeper inside into the functional meaning of epigenetic plasticity in the development.

A pilot reverse virtual screening study suggests toxic exposures caused long-term epigenetic changes in Gulf War Illness

“…Subsequent analysis looking specifically at gene expression and protein expression/function are warranted to confirm the potential effects of the DNA methylation changes in GWI noted herein. Furthermore, even if overall gene and protein expression/function are affected by the epigenetic changes caused by GWI related toxic exposures this alone may not lead to health impairments but may confer positive adaptive responses expected to have a survival advantage [79] . Again, this suggests investigating correlation between individual methylation status and GWI phenotype.…”

Canada’s Colonial Genocide of Indigenous Peoples: A Review of the Psychosocial and Neurobiological Processes Linking Trauma and Intergenerational Outcomes

“…Natural selection involves advantageous gene mutations being passed on across generations, thereby enhancing resilience and increasing the fitness of successive generations. In a similar fashion, certain epigenetic effects may persist across generations because they promote resilience, enhancing adaptations that facilitate health and survival [ 174 ]. As we know, certain phenotypes linked to mutations are selected because they have survival advantages so that preferred genes can be passed on across generations.…”

Phenotypic plasticity as a facilitator of microbial evolution

“…For example, multistable gene expression states can easily be formed on purely non-genetic grounds when there is positive feedback and sufficient non-linearity among the system components; with each gene expression state being optimal for a different environment, multistability can constitute a passive strategy to protect cellular populations from extinction [ 12 ]. As another example, when activated by environmental cues, epigenetic mechanisms not only increase expression plasticity for the environments to select on, but they can also guide the gene expression profiles to more optimal regimes dictated by the current environment [ 13 ].…”