Environmental epigenetics: a mechanistic approach to describing persistent effects of PAHs in birds

科学家们越来越意识到，生命早期暴露于环境压力可能对以后的健康产生持久影响。其中一些持续的影响可能是由于胚胎发育中表观遗传标记的化学修饰，如DNA甲基化。这一概念近年来一直是生物医学领域大量研究的焦点，并将对生态科学产生同样重要的（但尚未实现的）影响。 迄今为止，只有少数研究将表观遗传学原理应用于生态毒理学领域。这一领域的研究潜力令人兴奋。表观遗传学可能提供一个新的视角，早期生活暴露于环境化学品对野生动物种群的健康的影响。通过表观遗传学，个体在胚胎时期经历的环境条件有可能影响对未来暴露的反应，一生的健康，甚至后代的健康。这一想法对生态毒理学的许多领域都有重要意义，包括风险评估、生物监测和阐明作用机制。 我的研究计划的长期目标是调查是否出生前暴露于环境化学物质通过表观遗传机制导致鸟类野生动物的持续和跨代影响。首先，我将对这个问题采取一种机械的方法，重点关注一类称为多环芳烃（PAH）的化学物质。这些有毒化学品在环境中广泛存在，对野生鸟类的健康构成威胁。 我的研究项目的近期目标是确定DNA甲基化在介导鸟类对多环芳烃的持续反应中的作用。将评估DNA甲基化与PAH介导的基因表达变化在个体一生中、再次暴露时和多代之间的持续性的关系。这项工作最初将通过鸡的发育研究和日本鹌鹑的多代研究来完成。这些发现将通过观察在自然条件下暴露于多环芳烃的鸟类的类似终点来转化为生态环境。 总的来说，这项工作将提供高质量的数据，这将有助于对鸟类中的多环芳烃进行风险评估，并将建立一个框架，用于研究环境污染物的持久性和表观遗传效应。

There is a growing awareness among scientists that exposure to environmental stress early in life can have lasting impacts on health later in life. Some of these persistent effects may be due to chemical modifications to epigenetic marks, such as DNA methylation, in developing embryos. This concept has been the focus of a tremendous amount of research in the biomedical field in recent years, and will have an equally important (and as of yet unrealized) impact on the ecological sciences. To date, only a handful of studies have applied epigenetic principles to the field of ecotoxicology. The potential for research in this area is exciting. Epigenetics may provide a new perspective on the impact that early-life exposures to environmental chemicals have on the health of populations of wildlife. With epigenetics, environmental conditions that an individual experiences as an embryo have the potential to influence responses to future exposures, health throughout life, and even the health of descendants. This idea has important implications for many areas of ecotoxicology, including risk assessment, biomonitoring, and the elucidation of mechanisms of action. The long-term goal of my research program is to investigate whether pre-natal exposure to environmental chemicals causes persistent and transgenerational effects in avian wildlife through epigenetic mechanisms. I will initially take a mechanistic approach to this question, focusing on a class of chemicals called polycyclic aromatic hydrocarbons (PAHs). These toxic chemicals are widespread in the environment and pose a risk to the health of wild populations of birds. The near-term goal of my research program is to determine the role of DNA methylation in mediating persistent responses to PAHs in birds. DNA methylation will be assessed in relation to the persistence of PAH-mediated changes in gene expression throughout the life of the individual, upon re-exposure, and across multiple generations. This work will initially be accomplished through developmental studies with chicken, and multi-generational studies with Japanese quail. The findings will be translated to an ecological setting by looking at similar endpoints in birds that have been exposed to PAHs under natural conditions. Overall, this work will provide high quality data that will facilitate risk assessment for PAHs in birds, and will establish a framework for studying the persistent and epigenetic effects of environmental contaminants.