Titanium dioxide nanoparticles promote oxidative stress, autophagy and reduce NLRP3 in primary rat astrocytes
Titanium dioxide nanoparticles promote oxidative stress, autophagy and reduce NLRP3 in primary rat astrocytes
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DOI：
10.1016/j.cbi.2020.108966
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发表时间：
2020-02-01
影响因子：
5.1
通讯作者：
Lopez-Marure, Rebeca
中科院分区：
文献类型：
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作者：
Antonio Perez-Arizti, Jose;Luis Ventura-Gallegos, Jose;Lopez-Marure, Rebeca
二氧化钛纳米粒子（TiO2-NPs）广泛应用于食品工业、化妆品、个人护理和油漆等领域。通过职业接触和日常摄入，TiO2-NPs因其体积小，可通过口腔、皮肤、吸入等不同途径进入体内，并在包括大脑在内的多个器官中积累。 TiO2-NPs 对许多细胞类型造成严重损害，但它们对中枢神经系统的影响在很大程度上仍未被探索。因此，在本研究中，我们确定了 TiO2-NPs 对大鼠星形胶质细胞的细胞毒性作用。我们通过 DTT 消耗测试了 TiO2-NP 的氧化特性，并通过 2,7-二氯二氢荧光素二乙酸酯 (H(2)DCFDA) 的氧化和 Mitotracker Green FM 线粒体膜电位 (Delta Psi m) 的损失测量了氧化应激引起的线粒体损伤。我们进一步检查了氧化应激衍生的反应，例如通过蛋白质印迹检测 I kappa B-α 降解，通过 EMSA 检测 NF-kappa B 易位，通过 LC3-II 水平诱导自噬，以及炎症体蛋白 NLRP3 的表达。 TiO2-NPs 显示出高氧化特性，并在星形胶质细胞内化后诱导强烈的氧化应激，导致通过 Delta Psi m 损失检测到的线粒体损伤。针对氧化损伤（如 NF-κB 易位和自噬）的反应被诱导，并且 NLRP3 蛋白表达下调，表明星形胶质细胞中炎症体介导的反应较低。这些结果支持 TiO2-NPs 对星形胶质细胞的细胞毒性，星形胶质细胞在神经元稳态中发挥关键作用，其功能障碍可导致神经系统疾病，包括认知障碍和记忆丧失。
Titanium dioxide nanoparticles (TiO2-NPs) are widely used in the food industry, cosmetics, personal care and paints among others. Through occupational exposure and daily consumption, and because of their small size, TiO2-NPs can enter the body through different routes such as oral, dermal and inhalation, and accumulate in multiple organs including the brain. TiO2-NPs cause severe damage to many cell types, however their effects in the central nervous system remain largely unexplored. Therefore, in the present study we determined the cytotoxic effect of TiO2-NPs on rat astrocytes. We tested the oxidant properties of TiO2-NPs through DTT depletion, and measured oxidative stress-induced damage in mitochondria, through oxidation of 2,7-dichlorodihydrofluorescein diacetate (H(2)DCFDA) and loss of mitochondrial membrane potential (Delta Psi m) with Mitotracker Green FM. We further examined oxidative stress-derived responses such as I kappa B-alpha degradation by Western Blot, NF-kappa B translocation by EMSA, autophagy induction by LC3-II levels, and expression of the inflammasome protein NLRP3. TiO2-NPs showed high oxidant properties and induced strong oxidative stress in astrocytes following their internalization, causing mitochondrial damage detected by Delta Psi m loss. Responses against oxidative damage such as NF-kappa B translocation and autophagy were induced and NLRP3 protein expression was downregulated, indicating lower inflammasome-mediated responses in astrocytes. These results support TiO2-NPs cytotoxicity in astrocytes, cells that play key roles in neuronal homeostasis and their dysfunction can lead to neurological disorders including cognitive impairment and memory loss.