title: Quantum dots induced monocyte chemotactic protein-1 expression via MyD88-dependent Toll-like receptor signaling pathways in macrophages.
abstract: 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.
authors.affiliation: Institute of NanoEngineering and Microsystems, National Tsing Hua University, Hsinchu, Taiwan, ROC.
authors.forename: Chia-Chi
authors.initials: CC
authors.lastname: Ho
authors.forename: Yueh-Hsia
authors.initials: YH
authors.lastname: Luo
authors.forename: Tsung-Hsien
authors.initials: TH
authors.lastname: Chuang
authors.forename: Chung-Shi
authors.initials: CS
authors.lastname: Yang
authors.forename: Yong-Chien
authors.initials: YC
authors.lastname: Ling
authors.forename: Pinpin
authors.initials: P
authors.lastname: Lin
mesh_terms: D000818:Animals; D002460:Cell Line; D018932:Chemokine CCL2 / Q000096:biosynthesis* / Q000235:genetics; D002863:Chromogenic Compounds / Q000494:pharmacology*; D005786:Gene Expression Regulation / Q000187:drug effects; D008264:Macrophages / Q000378:metabolism*; D051379:Mice; D053594:Myeloid Differentiation Factor 88 / Q000096:biosynthesis / Q000502:physiology*; D010316:Particle Size; D045663:Quantum Dots; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D051193:Toll-Like Receptors / Q000502:physiology*
chemical_list: C491768:Ccl2 protein, mouse; D018932:Chemokine CCL2; D002863:Chromogenic Compounds; C507780:Myd88 protein, mouse; D053594:Myeloid Differentiation Factor 88; D051193:Toll-Like Receptors