Quantum dots induced monocyte chemotactic protein-1 expression via MyD88-dependent Toll-like receptor signaling pathways in macrophages.

Chia-Chi Ho, Yueh-Hsia Luo, Tsung-Hsien Chuang, Chung-Shi Yang, Yong-Chien Ling, Pinpin Lin

Institute of NanoEngineering and Microsystems, National Tsing Hua University, Hsinchu, Taiwan, ROC.

Toxicology 2013 Jun 7

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Quantum dots (QDs) are nano-sized semiconductors. Previously, intratracheal instillation of QD705s induces persistent inflammation in mouse lungs. In our present study, QD705-COOH and QD705-PEG activated NF-κB and increased monocyte chemotactic protein-1 (MCP-1) expression in macrophages RAW264.7 via MyD88 dependent Toll-like receptor (TLR) signaling pathways. MyD88 is an adapter protein for most TLRs to activate NF-κB. Silencing expression of MyD88 or p65 with siRNA or co-treatment with a NF-κB inhibitor tremendously abolished QD705s-induced NF-κB activity and MCP-1 expression. The involved TLRs might locate either on the cell surface or inside of cells. Co-treatment with a TLR4 inhibitor completely prevented MCP-1 induction by QD705-PEG. Nevertheless, QD705-COOH readily entered cells, and co-treatment with either inhibitors of endocytosis or intracellular TLRs prevented MCP-1 induction. These findings indicate that, depending on their surface modification, OD705s activate MyD88 dependent-TLRs at the surface or inside of the cells, which is an important mechanism for nanoparticles-induced inflammatory responses. But other MyD88-independent pathways may also involve in these responses. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Citation

Chia-Chi Ho, Yueh-Hsia Luo, Tsung-Hsien Chuang, Chung-Shi Yang, Yong-Chien Ling, Pinpin Lin. Quantum dots induced monocyte chemotactic protein-1 expression via MyD88-dependent Toll-like receptor signaling pathways in macrophages. Toxicology. 2013 Jun 7;308:1-9