School of Environment and Civil Engineering, Dongguan University of Technology, Dongguan 523808, Guangdong, PR China.
School of Environment and Civil Engineering, Dongguan University of Technology, Dongguan 523808, Guangdong, PR China; School of Environment and Energy, South China University of Technology, Guangzhou 510006, Guangdong, PR China.
Ecotoxicol Environ Saf. 2019 Mar;169:370-375. doi: 10.1016/j.ecoenv.2018.11.053. Epub 2018 Nov 19.
Modified nano-graphene quantum dots (M-GQDs) are widely used in bioimaging, drug delivery, and chemical engineering. Because M-GQDs could induce reactive oxygen species and DNA damage, we hypothesized that M-GQDs modulate DNA methylation. To test this hypothesis, zebrafish were exposed to reduced, hydroxylated, or aminated GQDs (graphene quantum dots) at different concentrations for 7 days; global DNA methylation in liver, gill, and intestine was then studied. M-GQDs induced global DNA hypermethylation in various tissues in a dose-dependent manner. The global DNA methylation of reduced and aminated GQDs exposure showed a significant increase in intestines even at low concentrations (2 mg/L), suggesting that intestines are the main target for these two M-GQDs. The effects of global DNA methylation were evaluated 14 days after exposure had ceased. DNA methylation in the livers of exposure groups was significantly higher than in control zebrafish. Global DNA methylation increased in livers of zebrafish even after exposure to aminated GQDs (2 mg/L) had ceased, indicating a more complex mechanism of DNA methylation deregulation. The present results showed that chemical groups in the surface of GQDs are a critical factor for modulating DNA methylation.
修饰后的纳米石墨烯量子点（M-GQDs）被广泛应用于生物成像、药物输送和化学工程领域。由于 M-GQDs 可以诱导活性氧和 DNA 损伤，我们假设 M-GQDs 可以调节 DNA 甲基化。为了验证这一假设，我们将斑马鱼暴露于不同浓度的还原、羟基化或氨基化 GQDs（石墨烯量子点）中 7 天；然后研究了肝脏、鳃和肠道中的全基因组 DNA 甲基化情况。M-GQDs 以剂量依赖的方式在各种组织中诱导全基因组 DNA 超甲基化。还原和氨基化 GQDs 暴露的全基因组 DNA 甲基化在低浓度（2mg/L）时，在肠道中呈现出显著增加，表明肠道是这两种 M-GQDs 的主要靶标。在暴露停止 14 天后，评估了全基因组 DNA 甲基化的影响。暴露组肝脏中的 DNA 甲基化明显高于对照组斑马鱼。即使在停止暴露氨基化 GQDs（2mg/L）后，斑马鱼肝脏中的全基因组 DNA 甲基化仍会增加，这表明 DNA 甲基化失调的机制更为复杂。本研究结果表明，GQDs 表面的化学基团是调节 DNA 甲基化的关键因素。
