ERK pathway is activated in bare-FeNPs-induced autophagy
ERK pathway is activated in bare-FeNPs-induced autophagy
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DOI：
10.1007/s00204-013-1134-1
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发表时间：
2013-09
影响因子：
6.1
通讯作者：
Eun-Jung Park;H. Umh;Sang-Wook Kim;M. Cho;Jae-Ho Kim;Younghun Kim
中科院分区：
文献类型：
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作者：
Eun-Jung Park;H. Umh;Sang-Wook Kim;M. Cho;Jae-Ho Kim;Younghun Kim
氧化铁纳米颗粒（FeNPs）是已知的最具生物相容性和安全性的纳米颗粒之一。然而，它们的长期持久性仍然是一个问题，由于纳米颗粒的生物持久性，巨噬细胞在持续刺激免疫系统中发挥着重要的中介作用。在本研究中，我们利用小鼠腹膜巨噬细胞系RAW264.7细胞确定了裸fenps摄取和毒性的机制。裸fenps通过静电相互作用与一般吞噬途径穿透细胞膜。暴露24 h后，它们在细胞质或自噬体样液泡内自由分布。裸fenps诱导细胞活力下降，细胞周期停滞在G1期。此外，它们还增加了ROS的产生、NO和TNF α的分泌以及抗氧化剂SOD-1和SOD-2蛋白的表达。虽然线粒体钙水平、标记线粒体强度和ATP产生降低，但自噬相关蛋白（如p62、beclin 1、ATG5和LC3B）的水平与ATF 3、p-EGFR和p-ERK蛋白的水平呈剂量依赖性增加。p-JNK蛋白水平明显降低。TEM图像还显示，受损细胞器存在于具有裸fenps的自噬体样液泡中。基于这些结果，我们认为裸fenps通过启动RAW264.7细胞的氧化应激诱导自噬。此外，在裸fenps诱导的自噬中，ERK通路被激活，而JNK通路未被激活。
Iron oxide nanoparticles (FeNPs) are known to be one of the most biocompatible and safe nanoparticles. However, their long-term persistence remains a problem, and macrophages play as an important mediator in continuous stimulation of the immune system due to biopersistence of nanoparticles. In the present study, we identified the mechanisms underlying the uptake and toxicity of bare-FeNPs using RAW264.7 cells, a mouse peritoneal macrophage cell line. The bare-FeNPs penetrated the cell membrane through electrostatic interactions together with the general phagocytic pathway. At 24 h after exposure, they distributed freely in the cytosol or within autophagosome-like vacuoles. Bare-FeNPs induced decrease in the cell viability along with the cell cycle arrest in G1 phase. In addition, they increased the generation of ROS and the secretion of NO and TNF alpha as well as the expression of SOD-1 and SOD-2 proteins, which are an antioxidant. While the mitochondrial calcium level, the intensity of labeled mitochondria, and ATP production decreased, the levels of autophagy-related proteins such as p62, beclin 1, ATG5, and LC3B increased in a dose-dependent manner together with the levels of ATF 3, p-EGFR, and p-ERK proteins. However, the level of p-JNK protein clearly decreased. TEM images also showed that damaged organelle exist within autophagosome-like vacuoles with bare-FeNPs. On the basis of these results, we suggest that bare-FeNPs induce autophagy by initiating oxidative stress in RAW264.7 cells. Furthermore, ERK, but not JNK, pathway is activated in bare-FeNPs-induced autophagy.