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

Research output: Contribution to journalArticlepeer-review

36 Scopus citations

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.

Original languageEnglish
Pages (from-to)1-9
Number of pages9
JournalToxicology
Volume308
DOIs
StatePublished - 7 Jun 2013

Keywords

  • Inflammation
  • MCP-1
  • MyD88
  • NF-κB
  • QD705
  • TLRs

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