Graduate School, Academy of Military Medical Sciences, Beijing, People's Republic of China.
Department of Operational Medical Protection, PLA Center for Disease Control and Prevention, Beijing, People's Republic of China.
Int J Nanomedicine. 2020 Apr 21;15:2669-2683. doi: 10.2147/IJN.S249912. eCollection 2020.
Zinc oxide nanoparticles (ZnO NPs) are one of the most widely used nanomaterials in a variety of fields such as industrial, pharmaceutical, and household applications. Increasing evidence suggests that ZnO NPs could elicit unignorable harmful effect to the cardiovascular system, but the potential deleterious effects to human cardiomyocytes remain to be elucidated. Human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) have been increasingly used as a promising in vitro model of cardiomyocyte in various fields such as drug cardiac safety evaluation. Herein, the present study was designed to elucidate the cardiac adverse effects of ZnO NPs and explore the possible underlying mechanism using hiPSC-CMs.
ZnO NPs were characterized by transmission electron microscopy and dynamic light scattering. The cytotoxicity induced by ZnO NPs in hiPSC-CMs was evaluated by determination of cell viability and lactate dehydrogenase release. Cellular reactive oxygen species (ROS) and mitochondrial membrane potential were measured by high-content analysis (HCA). Mitochondrial biogenesis was assayed by detection of mtDNA copy number and PGC-1α pathway. Moreover, microelectrode array techniques were used to investigate cardiac electrophysiological alterations.
We demonstrated that ZnO NPs concentration- and time-dependently elicited cytotoxicity in hiPSC-CMs. The results from HCA revealed that ZnO NPs exposure at low-cytotoxic concentrations significantly promoted ROS generation and induced mitochondrial dysfunction. We further demonstrated that ZnO NPs could impair mitochondrial biogenesis and inhibit PGC-1α pathway. In addition, ZnO NPs at insignificantly cytotoxic concentrations were found to trigger cardiac electrophysiological alterations as evidenced by decreases of beat rate and spike amplitude.
Our findings unveiled the potential harmful effects of ZnO NPs to human cardiomyocytes that involve mitochondrial biogenesis and the PGC-1α pathway that could affect cardiac electrophysiological function.
氧化锌纳米粒子（ZnO NPs）是一种在工业、制药和家庭应用等多种领域广泛应用的纳米材料。越来越多的证据表明，ZnO NPs 可能对心血管系统产生不可忽视的有害影响，但 ZnO NPs 对人类心肌细胞的潜在有害影响仍有待阐明。人诱导多能干细胞衍生的心肌细胞（hiPSC-CMs）已越来越多地被用作各种领域，如药物心脏安全性评估的心肌细胞的有前途的体外模型。在此，本研究旨在利用 hiPSC-CMs 阐明 ZnO NPs 的心脏不良影响，并探讨其潜在的机制。
通过透射电子显微镜和动态光散射对 ZnO NPs 进行了表征。通过测定细胞活力和乳酸脱氢酶释放来评估 ZnO NPs 在 hiPSC-CMs 中的细胞毒性。通过高内涵分析（HCA）测定细胞内活性氧（ROS）和线粒体膜电位。通过检测 mtDNA 拷贝数和 PGC-1α 通路来测定线粒体生物发生。此外，还使用微电极阵列技术研究心脏电生理变化。
我们证明了 ZnO NPs 浓度和时间依赖性地在 hiPSC-CMs 中产生细胞毒性。HCA 的结果表明，ZnO NPs 暴露在低细胞毒性浓度下会显著促进 ROS 生成并诱导线粒体功能障碍。我们进一步证明，ZnO NPs 可损害线粒体生物发生并抑制 PGC-1α 通路。此外，在无明显细胞毒性浓度下，ZnO NPs 被发现可触发心脏电生理变化，表现为心率和尖峰幅度降低。
我们的研究结果揭示了 ZnO NPs 对人类心肌细胞的潜在有害影响，涉及线粒体生物发生和 PGC-1α 通路，可能影响心脏电生理功能。
