Department of Environmental Science, Stockholm University, SE-106 91 Stockholm, Sweden.
Department of Materials and Environmental Chemistry, Stockholm University, SE-106 91 Stockholm, Sweden.
Environ Sci Technol. 2023 Jul 25;57(29):10591-10603. doi: 10.1021/acs.est.3c00499. Epub 2023 Jun 21.
Exposure to chemical pollution can induce genetic and epigenetic alterations, developmental changes, and reproductive disorders, leading to population declines in polluted environments. These effects are triggered by chemical modifications of DNA nucleobases (DNA adducts) and epigenetic dysregulation. However, linking DNA adducts to the pollution load remains challenging, and the lack of evidence-based DNA adductome response to pollution hampers the development and application of DNA adducts as biomarkers for environmental health assessment. Here, we provide the first evidence for pollution effects on the DNA modifications in wild populations of Baltic sentinel species, the amphipod . A workflow based on high-resolution mass spectrometry to screen and characterize genomic DNA modifications was developed, and its applicability was demonstrated by profiling DNA modifications in the amphipods collected in areas with varying pollution loads. Then, the correlations between adducts and the contaminants level (polycyclic aromatic hydrocarbons (PAHs), trace metals, and pollution indices) in the sediments at the collection sites were evaluated. A total of 119 putative adducts were detected, and some (5-me-dC, N-me-dA, 8-oxo-dG, and dI) were structurally characterized. The DNA adductome profiles, including epigenetic modifications, differed between the animals collected in areas with high and low contaminant levels. Furthermore, the correlations between the adducts and PAHs were similar across the congeners, indicating possible additive effects. Also, high-mass adducts had significantly more positive correlations with PAHs than low-mass adducts. By contrast, correlations between the DNA adducts and trace metals were stronger and more variable than for PAHs, indicating metal-specific effects. These associations between DNA adducts and environmental contaminants provide a new venue for characterizing genome-wide exposure effects in wild populations and apply DNA modifications in the effect-based assessment of chemical pollution.
暴露于化学污染物会引起遗传和表观遗传改变、发育变化和生殖障碍，导致污染环境中的种群减少。这些效应是由 DNA 碱基的化学修饰（DNA 加合物）和表观遗传失调引发的。然而，将 DNA 加合物与污染负荷联系起来仍然具有挑战性，并且缺乏基于证据的 DNA 加合物对污染的反应，这阻碍了 DNA 加合物作为环境健康评估生物标志物的开发和应用。在这里，我们提供了波罗的海指示物种（端足目桡足类）野生种群中 DNA 修饰受污染影响的第一个证据。开发了一种基于高分辨率质谱筛选和表征基因组 DNA 修饰的工作流程，并通过在具有不同污染负荷的区域收集的桡足类动物中对 DNA 修饰进行分析来证明其适用性。然后，评估了加合物与沉积物中污染物水平（多环芳烃（PAHs）、痕量金属和污染指数）之间的相关性。共检测到 119 种假定的加合物，其中一些（5-me-dC、N-me-dA、8-oxo-dG 和 dI）进行了结构表征。在高污染和低污染地区采集的动物的 DNA 加合物组图谱，包括表观遗传修饰，存在差异。此外，加合物与 PAHs 之间的相关性在同系物之间相似，表明可能存在加和效应。此外，高分子量加合物与 PAHs 的相关性比低分子量加合物更显著。相比之下，DNA 加合物与痕量金属之间的相关性比与 PAHs 的相关性更强且更具变异性，表明存在金属特异性效应。这些 DNA 加合物与环境污染物之间的关联为描述野生种群中全基因组暴露效应提供了新的途径，并将 DNA 修饰应用于化学污染的基于效应的评估。
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