ERK pathway is activated in bare-FeNPs-induced autophagy
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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.
KeywordsIron oxide nanoparticles Macrophage Autophagy ERK Mitochondria
We are very thankful to Bengt Fadeel, Karolinska Institute for helpful discussions. This work was supported by the Basic Science Research Program through the National Research Foundation of Korea funded by the Ministry of Education, Science, and Technology (2011-35B-E00011). Part of this work was also supported by National Research Foundation grant (2011-0019175) funded by the Korea government (MEST). In addition, M.H.C acknowledges the support of the Veterinary Research Institute of Seoul National University in Korea.
Conflict of interest
The authors report no conflicts of interest.
- Fan F, Jin S, Amundson SA, Tong T, Fan W, Zhao H, Zhu X, Mazzacurati L, Li X, Petrik KL, Fomace AJ Jr, Rajasekaran B, Zhan Z (2002) ATF3 induction following DNA damage is regulated by distinct signaling pathways and over-expression of ATF3 protein suppresses cells growth. Oncogene 21:7488–7496PubMedCrossRefGoogle Scholar
- Lavicoli I, Leso V, Fontana L, Bergamaschi A (2011) Toxicological effects of titanium dioxide nanoparticles: a review of in vitro mammalian studies. Eur Rev Med Pharmacol Sci 15:481–508Google Scholar
- Ling D, Hyeon T (2013) Chemical design of biocompatible iron oxide nanoparticles for medical applications. Small 9(9–10):1450–1466Google Scholar
- Matsumoto A, Naito M, Itakura H, Ikemoto S, Asaoka H, Hayakawa I, Kanamori H, Aburatani H, Takaku F, Suzuki H, Kobari Y, Miyai T, Takahashi K, Cohenii EH, Wydroii R, Housman DE, Kodama T (1990) Human macrophage scavenger receptors: primary structure, expression, and localization in atherosclerotic lesions. Proc Natl Acad Sci USA 87:9133–9137PubMedCrossRefGoogle Scholar
- Roitt IM, Brostoff J, Male DK (1985) Immunology. Gower Medical Pub.; C.V. Mosby, London; New York St. LouisGoogle Scholar
- Suzuki H, Kurihara Y, Takeya M, Kamada N, Kataoka M, Jishage K, Ueda O, Sakaguchi H, Higashi T, Suzuki T, Takashima Y, Kawabe Y, Cynshi O, Wada Y, Honda M, Kurihara H, Aburatani H, Doi T, Matsumoto A, Azuma S, Noda T, Toyoda Y, Itakura H, Yazaki Y, Horiuchi S, Takahashi K, Kruijt JK, Van Berker T, Steinbrecher UP, Ishibashi S, Maeda N, Gordon S, Kodama T (1997b) A role for macrophage scavenger receptors in atherosclerosis and susceptibility to infection. Nature 386:292–296Google Scholar
- Yin N, Liu Q, Liu J, He B, Cui L, Li Z, Yun Z, Qu G, Liu S, Zhou Q, Jiang G (2013) Silver nanoparticle exposure attenuates the viability of rat cerebellum granule cells through apoptosis coupled to oxidative stress. Small 9(9–10):1831–1841Google Scholar