Department of Biology & CESAM - Centre for Environmental and Marine Studies, University of Aveiro, Portugal.
Department of Biology & CESAM - Centre for Environmental and Marine Studies, University of Aveiro, Portugal; CICECO - Aveiro Institute of Materials & Department of Chemistry, University of Aveiro, Portugal.
Chemosphere. 2022 Dec;308(Pt 1):136231. doi: 10.1016/j.chemosphere.2022.136231. Epub 2022 Aug 30.
Epigenetic mechanisms are moving to the forefront of environmental sciences, as environmentally induced epigenetic changes shape biological responses to chemical contamination. This work focused on Daphnia as a representative of potentially threatened freshwater biota, aiming to gain an insight into the involvement of epigenetic mechanisms in their response and eventual adaptation to metal contamination. Copper-induced DNA methylation changes, their potential transgenerational inheritance, and life-history traits were assessed. Organisms with different histories of past exposure to copper were exposed to toxic levels of the element for one generation (F0) and then monitored for three subsequent unexposed generations (F1, F2, and F3). Overall, methylation changes targeted important genes for counteracting the effects of metals and oxidative stress, including dynein light chain, ribosomal kinase and nuclear fragile X mental retardation-interacting protein. Also, contrasting overall and gene-specific methylation responses were observed in organisms differing in their history of exposure to copper, with different transgenerational methylation responses being also identified among the two groups, without apparent life-history costs. Taken together, these results demonstrate the capacity of copper to promote epigenetic transgenerational inheritance in a manner related explicitly to history of exposure, thereby supporting the development and incorporation of epigenetic biomarkers in risk assessment frameworks.
表观遗传机制正在成为环境科学的前沿领域，因为环境诱导的表观遗传变化塑造了生物对化学污染的反应。本研究以水蚤为潜在受威胁的淡水生物群的代表，旨在深入了解表观遗传机制在其对金属污染的反应和最终适应中的作用。评估了铜诱导的 DNA 甲基化变化、其潜在的跨代遗传以及生活史特征。具有不同过去铜暴露史的生物体在一代（F0）中暴露于有毒水平的金属元素下，然后监测三个后续未暴露的世代（F1、F2 和 F3）。总的来说，甲基化变化针对重要的基因，以对抗金属和氧化应激的影响，包括动力蛋白轻链、核糖体激酶和核脆性 X 智力迟钝相互作用蛋白。此外，在暴露于铜的历史不同的生物体中观察到了整体和基因特异性甲基化反应的对比，并且在这两个组中也鉴定出了不同的跨代甲基化反应，而没有明显的生活史成本。总之，这些结果表明铜具有促进与暴露史明确相关的表观遗传跨代遗传的能力，从而支持在风险评估框架中开发和纳入表观遗传生物标志物。
