School of Freshwater Sciences, University of Wisconsin-Milwaukee, 600 E Greenfield Ave., Milwaukee, Wisconsin 53204, United States.
Department of Chemistry, University of Wisconsin-Madison, 1101 University Ave., Madison, Wisconsin 53706, United States.
Chem Res Toxicol. 2021 Nov 15;34(11):2287-2297. doi: 10.1021/acs.chemrestox.1c00189. Epub 2021 Nov 1.
Growing evidence across organisms points to altered energy metabolism as an adverse outcome of metal oxide nanomaterial toxicity, with a mechanism of toxicity potentially related to the redox chemistry of processes involved in energy production. Despite this evidence, the significance of this mechanism has gone unrecognized in nanotoxicology due to the field's focus on oxidative stress as a universal─but nonspecific─nanotoxicity mechanism. To further explore metabolic impacts, we determined lithium cobalt oxide's (LCO's) effects on these pathways in the model organism through global gene-expression analysis using RNA-Seq and untargeted metabolomics by direct-injection mass spectrometry. Our results show that a sublethal 1 mg/L 48 h exposure of to LCO nanosheets causes significant impacts on metabolic pathways versus untreated controls, while exposure to ions released over 48 h does not. Specifically, transcriptomic analysis using DAVID indicated significant enrichment (Benjamini-adjusted ≤0.0.5) in LCO-exposed animals for changes in pathways involved in the cellular response to starvation (25 genes), mitochondrial function (70 genes), ATP-binding (70 genes), oxidative phosphorylation (53 genes), NADH dehydrogenase activity (12 genes), and protein biosynthesis (40 genes). Metabolomic analysis using MetaboAnalyst indicated significant enrichment (γ-adjusted <0.1) for changes in amino acid metabolism (19 metabolites) and starch, sucrose, and galactose metabolism (7 metabolites). Overlap of significantly impacted pathways by RNA-Seq and metabolomics suggests amino acid breakdown and increased sugar import for energy production. Results indicate that LCO-exposed respond to energy starvation by altering metabolic pathways, both at the gene expression and metabolite levels. These results support altered energy production as a sensitive nanotoxicity adverse outcome for LCO exposure and suggest negative impacts on energy metabolism as an important avenue for future studies of nanotoxicity, including for other biological systems and for metal oxide nanomaterials more broadly.
越来越多的证据表明，改变能量代谢是金属氧化物纳米材料毒性的不良后果，其毒性机制可能与涉及能量产生的过程的氧化还原化学有关。尽管有这些证据，但由于该领域专注于氧化应激作为普遍（但非特异性）的纳米毒性机制，纳米毒理学领域尚未认识到这一机制的重要性。为了进一步探索代谢影响，我们通过 RNA-Seq 进行了全局基因表达分析，并通过直接注射质谱进行了非靶向代谢组学分析，确定了模型生物中钴酸锂（LCO）对这些途径的影响。我们的结果表明，亚致死浓度 1mg/L 的 LCO 纳米片在 48 小时暴露下，与未处理对照组相比，对代谢途径有显著影响，而在 48 小时内释放的离子暴露则没有。具体来说，使用 DAVID 的转录组分析表明，在暴露于 LCO 的动物中，参与细胞对饥饿反应的途径（25 个基因）、线粒体功能（70 个基因）、ATP 结合（70 个基因）、氧化磷酸化（53 个基因）、NADH 脱氢酶活性（12 个基因）和蛋白质生物合成（40 个基因）发生了显著富集（Benjamini 调整 ≤0.05）。使用 MetaboAnalyst 的代谢组学分析表明，在氨基酸代谢（19 种代谢物）和淀粉、蔗糖和半乳糖代谢（7 种代谢物）方面发生了显著富集（γ 调整 <0.1）。RNA-Seq 和代谢组学显著影响的途径重叠表明，LCO 暴露的 通过氨基酸分解和增加糖的摄取来产生能量。结果表明，暴露于 LCO 的 通过改变基因表达和代谢物水平的代谢途径来应对能量饥饿。这些结果支持改变能量产生作为 LCO 暴露的敏感纳米毒性不良后果，并表明能量代谢的负面影响是未来纳米毒性研究的一个重要途径，包括其他生物系统和更广泛的金属氧化物纳米材料。
