The Toxicologist - Society of Toxicology

with immunocompetent cells is of special interest as these cells are present throughout
the body and are crucial for the efficient recognition and elimination of
pathogens and foreign materials. Here, we investigated the adverse effects of largescale
produced ZnO nanoparticles on a human T cell leukemia-derived cell line
(Jurkat) and the underlying mechanisms. Already low concentrations of ZnO
nanoparticles induced major cell death including apoptotic and late
apoptotic/necrotic cells. Using mutant cell lines deficient in various components of
apoptotic signaling pathways we found that ZnO nanoparticles activate none of the
classical apoptotic mechanisms, namely extrinsic or mitochondrial apoptosis pathways.
However, reactive oxygen species are involved as the antioxidant agent Nacetylcystein
significantly reduced ZnO-induced apoptosis. No ZnO nanoparticles
were observed in treated cells but instead rapid dissolution and high concentrations
of Zn-ions were found both extra- and intracellularly. Removal of these ions in the
medium and/or within the cells completely inhibited ZnO-induced apoptosis. To
conclude, our study indicates that ZnO nanoparticle toxicity in Jurkat T cells is
predominantly mediated by Zn-ions and involves oxidative stress signaling mechanisms
but not the classical apoptotic pathways. Sponsored by the Seventh
Framework Programme of the European Commission (FP7-NANOMMUNE,
grant no. 214281)
2061 MACROPHAGE ACTIVATION AND MIGRATION ON
TRANSPARENT TITANIUM NANOSTRUCTURE.
D. Khang2 , S. Lee1 and S. Kim1 . 1Pharmacology, Kyungpook National University,
Daegu, Republic of Korea and 2Center for Nano-Morphic Biological Energy and
School of Nano and Advanced Materials Science and Engineering, Gyeongsang
National University, Jinju, Republic of Korea.
The immunotoxicity of implanted nanostructured titanium is a paramount issue
for vascular, dental and orthopedic applications. Here we report a deactivation of
macrophage immune response on nanostructured titanium surfaces. Basically, NO
and iNOS were significantly reduced on nano featured surfaces as compared with
flat. For examining cytoskeleton variation of macrophage, both confocal microscopy
and live cell recording system were used. Importantly, results indicated
that nano-bump-surfaces features inhibit the migration activity, such as migration
distance and migration speed within 12 hours. In addition, through the live cell
recording analysis, we found that level of activated macrophage on nanomaterials
were recovered within 24 hours, compared to flat titanium surfaces, after the initial
adhesion of macrophage on biomaterials. In western blot experiment, focal adhesion
kinase (FAK) and p-FAK, showed significant difference of cytoskeleton morphology
of macrophage at 4 hours. In conclusion, this study demonstrated the migration
of macrophage on nanomaterials was determined by nano surface
topography which led to quite different behavior (immunological aspect) compared
to flat surfaces in identical chemistry.
2062 ADHESIVE PROPERTIES OF HUMAN ENDOTHELIAL
CELLS EXPOSED TO AMORPHOUS SILICA
NANOPARTICLES.
D. H. Napierska 1 , R. Quarck 2 , L. Thomassen 3 , L. Gonzalez 4 , V. Rabolli 5 , D.
Lison 5 , M. Kirsch-Volders 4 , J. Martens 3 , M. Delcroix 2 , B. Nemery 1 and P. H.
Hoet 1 . 1 Research Unit for Lung Toxicology, K.U. Leuven, Leuven, Belgium,
2 Pulmonary Circulation Unit, K.U. Leuven, Leuven, Belgium, 3 Center for Surface
Chemistry & Catalysis, K.U. Leuven, Leuven, Belgium, 4 Free University of Brussels,
Brussels, Belgium and 5 Catholic University of Louvain, Brussels, Belgium.
The present study was undertaken to examine the effect of amorphous (monodisperse)
silica nanoparticles (SNP) of different sizes on endothelial cell function, in
the absence or presence of a previously established in vitro human airway model
consisting of triple cell co-cultures. An immortalized human endothelial cell line
(EA.hy926) and primary human pulmonary artery endothelial cells (hPAEC) were
seeded in inserts (apical compartment) which were introduced or not above triple
cell co-cultures in the basolateral compartment (pneumocytes (A549),
macrophages (THP-1), and mast cells (HMC-1)). Endothelial cells (EC) were incubated
with silica nanoparticles (hydrodynamic diameter of 28, 59 and 174 nm).
The adhesion of monocyte cell line (U937) to EC was assessed, and endothelin-1
(ET-1) levels in culture media were measured. Additionally, the expression of intercellular
adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1
(VCAM-1) was investigated in SNP-exposed EC. Exposure of EA.hy926 cells to 28
and 59 nm particles at non-toxic concentrations induced a significant increase in
U937 cell adhesion and decrease in ET-1 secretion (up to 2-fold). Both adhesion
and ET-secretion were increased when EC exposure to SNP was performed in the
presence of triple cell co-cultures. Exposure to all three SNP induced expression of
ICAM-1 but no VCAM-1 in the EA.hy926 cells, and both ICAM-1 and VCAM-1
in hPAEC cultures. Our results suggest that exposure of human endothelial cells to
amorphous silica nanoparticles influences adhesive properties of the studied cells.
Work was partially financed by the Belgian Ministry of Scientific Policy in the
frame of S2NANO project (contract number SD/HE/02A).
442 SOT 2011 ANNUAL MEETING
2063 CYTOTOXICITY OF SILVER NANOPARTICLES ON
JURKAT T CELLS.
H. Eom and J. Choi. University of Seoul, Seoul, Republic of Korea. Sponsor: D. Ryu.
In this study, to identify potential harmful effect of silver nanoparticles (AgNPs) on
human health, toxicity assay was conducted using human cells derived from various
organs, such as, Jurkat T, NCI-H460, HeLa, HepG2, MCF-7, and Beas-2B.
Among tested cell lines, Jurkat T cell shows a dramatically high sensitivity to
AgNPs exposure than to Ag ion. Therefore, mRNA and microRNA (miRNA) microarray
analysis was conducted on Jurkat T cells. Microarray results indicate that
more differentially expressed genes and miRNAs were induced by AgNPs than by
Ag ion and AgNPs induced gene expression were not clustered with control and Ag
ion induced ones. This may explain higher sensitivity of Jurkat T cell to AgNPs
than to Ag ion and also suggest toxicity of AgNPs took a distinct pathway from that
of Ag ion. Based on the results on microarrays and our previous study, oxidative
stress was thoroughly analyzed as mechanism of toxicity of AgNPs. Taken overall
results on oxidative stress parameters together, AgNPs exposure produce reactive
oxygen species (ROS) in Jurkat T cells, which activates p38 mitogen-activated protein
kinase (MAPK) through nuclear factor-E2-related factor-2 (Nrf-2) and nuclear
factor-kappaB (NF-κB) signaling pathway and further induce DNA damage, cell
cycle arrest and apoptosis. In conclusion, our result suggests AgNPs may induce significant
and selective toxicity on AgNPs on Jurkat T cell, including genotoxicity,
therefore rigorous toxicity evaluation and risk assessment should be conducted
using various different cell types and biological systems, prior to widespread use of
AgNPs. Acknowledgments : This work was supported and by the Mid-career
Researcher Program through National Research Foundation of Korea (NRF)
funded by the Ministry of Education, Science and Technology (2010-0027722)
and by the Basic Science Research Program through the National Research
Foundation of Korea(NRF) funded by the Ministry of Education, Science and
Technology (2010-0016195)
2064 TOXICOLOGICAL INVESTIGATION OF SILVER
NANOPARTICLES ON MAPK PATHWAYS AND
RELATED TRANSCRIPTION FACTORS IN
CAENOHABDITIS ELEGANS.
J. Roh, D. Lim, H. Eom, J. An and J. Choi. University of Seoul, Seoul, Republic
of Korea. Sponsor: D. Ryu.
In our previous study, the functional genomics analysis was conducted for investigation
of toxicity of silver nanoparticles in the nematode, Caenohabditis elegans; the
results suggests that oxidative stress seems to be an important mechanism of AgNPs
toxicity in C. elegans and pmk-1, p38 MAPK plays an important role in defense
process towards oxidative stress induced by AgNPs in C. elegans. In this study, to
identify pmk-1 dependant transcription factors and downstream genes, the response
of stress-response transcription factors (i.e. daf-16, cep, skn-1, hif-1) and that
of potentially stress response genes (i.e. gst-4, cyp35a2, sod-3 and mtl-2) was investigated
in presence of AgNPs in wildtype and pmk-1(km25) mutants using gene expression,
ROS formation and reproduction, as endpoints. Among tested transcription
factors, hif-1 seems to show pmk-1 dependant response. An increase in the
expression of gst-4 genes was observed in wildtype exposed to AgNPs, but which
was not observed in the pmk-1(km25) mutant, similar tendency was observed in
mtl-2 gene expression, which suggests that gst-4 and mtl-2 genes expression appears
to be dependent on p38 activation. The high expressions of the sod-3 gene in
AgNPs exposed pmk-1 (km25) mutant can be interpreted as compensatory mechanisms
in the absence of important stress response genes.
Keywords: Caenorhabditis elegans; silver nanoparticles; pmk-1, p38 mitogen activated
protein kinase; hif-1; gst-2; mtl-2
Acknowledgments : This work was supported by the Basic Science Research
Program through the National Research Foundation of Korea(NRF) funded by the
Ministry of Education, Science and Technology (2010-0016195) and by the “ The
Eco-technopia 21 project” of Korean Ministry of Environment.
2065 BIODISTRIBUTION AND PERSISTENCE OF FOUR
SIZES OF CERIA ENGINEERED NANOMATERIALS
AFTER INTRAVENOUS ADMINISTRATION.
M. Dan 1 , P. Wu 2 , M. T. Tseng 3 , U. M. Graham 2 , R. L. Florence 2 , J. M.
Unrine 2 , E. A. Grulke 2 and R. A. Yokel 1 . 1 Pharmaceutical Sciences, University of
Kentucky, Lexington, KY, 2 University of Kentucky, Lexington, KY and 3 University of
Louisville, Louisville, KY.
Objectives: To test the hypothesis that the size of engineered nanomaterials
(ENMs) affects their biodistribution and persistence. Methods: Aqueous dispersions
of ~ 5-, 15-, 30- and 65-nm ceria ENMs, synthesized and characterized in-