Division of Biological and Life Sciences, School of Arts and Sciences and ‡School of Engineering and Applied Sciences, Ahmedabad University , Navrangpura, Ahmedabad-380009, Gujarat, India.
Department of Molecular Biology and Microbiology, Burnett School of Biomedical Science and ∥Advanced Materials Processing and Analysis Centre, Nanoscience Technology Centre (NSTC), Materials Science and Engineering and College of Medicine, University of Central Florida , Orlando, Florida 32816, United States.
Langmuir. 2016 Nov 22;32(46):12202-12211. doi: 10.1021/acs.langmuir.6b03022. Epub 2016 Nov 9.
Cerium oxide nanoparticles (CeNPs) have gathered much attention in the biomedical field due to its unique antioxidant property. It can protect cells and tissues from oxidative stress induced damage due to its autoregenerative redox cycle. Our study explores the antioxidant and antigenotoxic behavior of PEGylated CeNPs toward oxidative insult produced by buthionine sulfoximine (BSO) in human keratinocytes (HaCaT cells). BSO inhibits the γ-glutamylcysteinesynthetase (γ-GCS) enzyme and thus acts as a glutathione (GSH) depleting agent to modulate the cellular redox potential. GSH is a natural ROS scavenger present in the mammalian cells, and its depletion causes generation of reactive oxygen species (ROS). In this study, we challenged HaCaT cells (keratinocytes) with BSO to alter the redox potential within the cell and monitored toxicity, ROS generation, and nuclear fragmentation. We also followed changes in expressions of related proteins and genes. We found that PEGylated CeNPs can protect HaCaT cells from BSO-induced oxidative damage. BSO-exposed cells, preincubated with PEGylated CeNPs, showed better cell survival and significant decrease in the intracellular levels of ROS. We also observed decrease in lactate dehydrogenase (LDH) release and nuclear fragmentation in CeNP-treated cells that were challenged with BSO as compared to treatment with BSO alone. Exposure of HaCaT cells with BSO leads to altered expression of antioxidant genes and proteins, i.e., thioredoxin reductase (TrxR) and peroxiredoxin 6 (Prx6) whereas, in our study, pretreatment of PEGylated CeNPs reduces the need for induction of genes that produce enzymes involved in the defense against oxidative stress. Since, growing evidence argued the involvement of ROS in mediating death of mammalian cells in several ailments, our finding reinforces the use of PEGylated CeNPs as a potent pharmacological agent under the lower cellular GSH/GSSG ratios for the treatment of diseases mediated by free radicals.
氧化铈纳米粒子 (CeNPs) 因其独特的抗氧化特性而在生物医学领域引起了广泛关注。由于其自动再生的氧化还原循环，它可以保护细胞和组织免受氧化应激诱导的损伤。我们的研究探讨了聚乙二醇化 CeNPs 对人角质形成细胞 (HaCaT 细胞) 中由丁硫氨酸亚砜胺 (BSO) 产生的氧化应激的抗氧化和抗原毒性作用。BSO 抑制 γ-谷氨酰半胱氨酸合成酶 (γ-GCS) 酶，因此作为谷胱甘肽 (GSH) 耗竭剂来调节细胞内氧化还原电势。GSH 是哺乳动物细胞中存在的天然 ROS 清除剂，其耗竭会导致活性氧 (ROS) 的产生。在这项研究中，我们用 BSO 挑战 HaCaT 细胞 (角质形成细胞) 以改变细胞内的氧化还原电势，并监测毒性、ROS 生成和核片段化。我们还跟踪了相关蛋白质和基因表达的变化。我们发现聚乙二醇化 CeNPs 可以保护 HaCaT 细胞免受 BSO 诱导的氧化损伤。用聚乙二醇化 CeNPs 预处理的 BSO 暴露细胞显示出更好的细胞存活率和显著降低的细胞内 ROS 水平。我们还观察到在用 BSO 处理的细胞中 LDH 释放和核片段化减少，而在用 BSO 单独处理的细胞中则没有观察到这种情况。用 BSO 暴露 HaCaT 细胞会导致抗氧化基因和蛋白质的表达改变，即硫氧还蛋白还原酶 (TrxR) 和过氧化物酶 6 (Prx6)，而在我们的研究中，聚乙二醇化 CeNPs 的预处理减少了诱导产生参与抗氧化应激防御的酶的基因的需要。由于越来越多的证据表明 ROS 参与介导几种疾病中哺乳动物细胞的死亡，我们的发现加强了在较低的细胞 GSH/GSSG 比下使用聚乙二醇化 CeNPs 作为一种有效的药理学制剂来治疗由自由基介导的疾病。
