Babele Piyoosh Kumar, Singh Ashwani Kumar, Srivastava Amit
Department of Biological Sciences, Indian Institute of Science Education and Research Bhopal, Bhopal, India.
School of Physical Sciences, Jawaharlal Nehru University, New Delhi, India.
Front Pharmacol. 2019 Sep 12;10:1016. doi: 10.3389/fphar.2019.01016. eCollection 2019.
Silver nanoparticles (AgNPs) have many applications in various fields, including biomedical applications. Due to the broad range of applications, they are considered as the leading fraction of manufactured nanoparticles. AgNPs are synthesized by different types of chemical and biological (green) methods. Previously, biologically synthesized AgNPs were considered safe for the environment and humans. However, new toxicity evidence have initiated a more careful assessment to delineate the toxicity mechanisms associated with these nanoparticles. This study demonstrates the use of aqueous gooseberry extract for AgNP preparation in a time- and cost-effective way. Ultraviolet-visible spectroscopy, X-ray diffraction, transmission electron microscopy, and dynamic light scattering confirm the formation of AgNPs, with an average size between 50 and 100 nm. Untargeted H-nuclear magnetic resonance-based metabolomics revealed manyfold up- and down-regulation in the concentration of 55 different classes of annotated metabolites in AgNP-exposed yeast cells. Based on their chemical nature and cellular functions, these metabolites are classified into amino acids, glycolysis and the tricarboxylic acid (TCA) cycle, organic acids, nucleotide metabolism, urea cycle, and lipid metabolism. Transcriptome analysis revealed that the genes involved in oxidative stress mitigation maintain their expression levels, whereas the genes of the TCA cycle and lipid metabolism show drastic down-regulation upon AgNP exposure. Moreover, they can induce alteration in histone epigenetic marks by altering the methylation and acetylation of selected histone H3 and H4 proteins. Altogether, we conclude that the selected dose of biologically synthesized AgNPs impose toxicity by modulating the transcriptome, epigenome, and metabolome of eukaryotic cells, which eventually cause disequilibrium in cellular metabolism leading to toxicity.
银纳米颗粒(AgNPs)在包括生物医学应用在内的各个领域都有许多应用。由于其广泛的应用范围,它们被认为是人造纳米颗粒的主要部分。AgNPs通过不同类型的化学和生物(绿色)方法合成。以前,生物合成的AgNPs被认为对环境和人类是安全的。然而,新的毒性证据引发了更仔细的评估,以阐明与这些纳米颗粒相关的毒性机制。本研究展示了以具有时间和成本效益的方式使用醋栗水提取物制备AgNPs。紫外可见光谱、X射线衍射、透射电子显微镜和动态光散射证实了AgNPs的形成,其平均尺寸在50至100纳米之间。基于非靶向氢核磁共振的代谢组学揭示了在暴露于AgNP的酵母细胞中55种不同类别的注释代谢物浓度有许多倍的上调和下调。根据它们的化学性质和细胞功能,这些代谢物被分类为氨基酸、糖酵解和三羧酸(TCA)循环、有机酸、核苷酸代谢、尿素循环和脂质代谢。转录组分析表明,参与减轻氧化应激的基因保持其表达水平,而TCA循环和脂质代谢的基因在暴露于AgNP后显示出急剧下调。此外,它们可以通过改变选定的组蛋白H3和H4蛋白的甲基化和乙酰化来诱导组蛋白表观遗传标记的改变。总之,我们得出结论,选定剂量的生物合成AgNPs通过调节真核细胞的转录组、表观基因组和代谢组来施加毒性,最终导致细胞代谢失衡从而产生毒性。