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


METHODS
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.
Department of Dentistry, Hallym University, Kyounggi-do, Korea.
An-Sook
AS
Kim
Chang-Hoon
CH
Chae
Juliana
J
Kim
Je-Yong
JY
Choi
Seong-Gon
SG
Kim
Grigore
G
Băciut
D000906:Antibodies / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects*; D045744:Cell Line, Tumor; D002478:Cells, Cultured; D019902:Chondrocytes / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D006801:Humans; D053768:Metal Nanoparticles; D010513:Periodontal Ligament / Q000166:cytology / Q000187:drug effects; D010766:Phosphorylation; D016755:Proto-Oncogene Proteins c-jun / Q000378:metabolism; D034741:RNA, Small Interfering / Q000378:metabolism; D015398:Signal Transduction; D012834:Silver / Q000494:pharmacology*; D051195:Toll-Like Receptor 2 / Q000235:genetics / Q000378:metabolism*
D000906:Antibodies; D016755:Proto-Oncogene Proteins c-jun; D034741:RNA, Small Interfering; D051195:Toll-Like Receptor 2; D012834:Silver