Silver nanoparticles induce apoptosis through the toll-like receptor 2 pathway

Oral Surg Oral Med Oral Pathol Oral Radiol. 2012 Jun;113(6):789-98. doi: 10.1016/j.oooo.2012.01.019.

Abstract

Objective: The objective of this study was to evaluate the effects of silver nanoparticles (AgNPs) on the Toll-like receptor 2 (TLR-2) pathway in cultured cells.

Study design: Human chondrocytes, periodontal ligament (PDL) cells, and SCC-9 cells (squamous cell carcinoma from the tongue) were cultured and subjected to cytotoxicity assays. To evaluate the effects of AgNPs on the TLR-2 pathway, TLR-2 small interfering (si) RNA or TLR-2 antibodies were applied to the chondrocytes, followed by the application of AgNPs.

Results: AgNPs induced dose-dependent effects on the examined cell types in terms of both cytotoxicity and TLR-2 expression levels. AgNP-mediated apoptosis was reduced after treatment with TLR-2 siRNA in both PDL cells and chondrocytes. Furthermore, functional blocking of TLR-2 with anti-TLR2 antibodies inhibited AgNP-mediated cytotoxicity. AgNPs increased c-Jun phosphorylation, an effect that was reversed after treatment with TLR-2 siRNA.

Conclusions: The results indicate that AgNP-mediated apoptosis most likely occurs via the TLR-2 pathway.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antibodies / pharmacology
  • Apoptosis / drug effects*
  • Cell Line, Tumor
  • Cells, Cultured
  • Chondrocytes / drug effects*
  • Dose-Response Relationship, Drug
  • Humans
  • Metal Nanoparticles*
  • Periodontal Ligament / cytology
  • Periodontal Ligament / drug effects
  • Phosphorylation
  • Proto-Oncogene Proteins c-jun / metabolism
  • RNA, Small Interfering / metabolism
  • Signal Transduction
  • Silver / pharmacology*
  • Toll-Like Receptor 2 / genetics
  • Toll-Like Receptor 2 / metabolism*

Substances

  • Antibodies
  • Proto-Oncogene Proteins c-jun
  • RNA, Small Interfering
  • Toll-Like Receptor 2
  • Silver