In Kyoung Kim

Analysis for the potential of polystyrene and TiO2 nanoparticles to induce skin irritation, phototoxicity, and sensitization.

The human skin equivalent model (HSEM) is well known as an attractive alternative model for evaluation of dermal toxicity. However, only limited data are available on the usefulness of a HSEM for nanotoxicity testing. This study was designed to investigate cutaneous toxicity of polystyrene and TiO2 nanoparticles using cultured keratinocytes, a HSEM, and an animal model. In addition, we also evaluated the skin sensitization potential of nanoparticles using a local lymph node assay with incorporation of BrdU. Findings from the present study indicate that polystyrene and TiO2 nanoparticles do not induce phototoxicity, acute cutaneous irritation, or skin sensitization. Results from evaluation of the HSEMs correspond well with those from animal models. Our findings suggest that the HSEM might be a useful alternative model for evaluation of dermal nanotoxicity.

Effects of tobacco compounds on gene expression in fetal lung fibroblasts

The goal of this study was to determine the effects of tobacco compounds on gene expression in a human fetal lung cell line (WI38). In the present study, we investigated the effects of tobacco compounds (nicotine, benzo(a)pyrene (B(a)P), and 2‐Naphthylamine) on gene expression profiles in human fetal fibroblasts using cDNA microarray and real‐time PCR. WI38 cells were cultured in Eagles minimum essential medium (MEM) supplemented with 10% fetal bovine serum, 2% 200 mM L‐glutamine, and a 2% penicillin and streptomycin solution. Tissue culture flasks (T‐25 cm2) containing confluent lung fibroblasts were incubated at 37°C for 24 h with 5 mL of medium supplemented with 10 μM of a tobacco compound (nicotine, B(a)P, or 2‐Naphthylamine). The gene expression profiles for the W138 cells varied depending on the tobacco compound. The cDNA microarray analysis revealed that apoptosis‐related genes such as DNASE2, MADD, MST1, NME3, RARG, TNFRSF1A, BAD, and DFFB genes were down‐regulated in tobacco compound‐treated WI38 cells. We also observed significant increases in Arnt gene expression by real‐time PCR in tobacco compound‐treated WI38 cells. Tobacco compounds can affect apoptosis, immunity, and growth in WI38 cells. A microarray‐based genomic survey is a high‐throughput approach for the evaluation of gene expression in cell lines treated with tobacco compounds.

Correlation between nutrition intake and gene expression profiles in children with asthma

Asthma is a complex inflammatory disease and its prevalence has increased worldwide, especially in young children. In this study, we used a ‘24-hour recall method’ to identify differences between children with and without asthma in energy intake and energy-adjusted nutrition intake. We also performed reverse transcription-polymerase chain reaction (RTPCR) with pathway-targeted arrays (RT2 Profiler™ PCR Array) to investigate the expression profiles of chemokines and cytokines in children with asthma. The intake of vitamin C in mild and moderate asthma was significantly higher than that in healthy controls. Vitamin E intake in the mild asthma group was also significantly higher. Twenty-three genes were expressed at higher levels in severe asthma compared with healthy controls. Using the human Th1-Th2-Th3 PCR Array, we found 17 genes were upregulated in severe asthma, including the Th2-related genes CCL7, IL13, and CCL-11 (eotaxin). These PCR Array results revealed that the genes that were most profoundly increased in asthma encoded for key proinflammatory and chemotactic molecules. Our observations lead us to speculate that the interaction between gene expression and dietary intake is important for the development of asthma.

Effect of tobacco compounds on gene expression profiles in human epithelial cells

This study was carried out to investigate the effects of the tobacco compounds (TC), nicotine, B(a)P, and 2-naphthylamine, on gene expression profiles in a human epithelial cells (A549). We treated A549 with the TC and analyzed gene expression using microarray and real-time PCR (RTP). Gene expression varied according to the TC used. By microarray, we found that apoptosis-related genes such as apoptosis-associated tyrosine kinase, interleukin 10 receptor beta, caspase 1 and DNA fragmentation factor beta subunit (40kDa) were down-regulated in TC-treated A549 cells. RTP showed significant increases in the expression of Ahr, Arnt, CYP1A1, and CYP1B1 in TC-treated A549 cells. From these results, we suggest that tobacco compounds can influence apoptosis, inflammation, immunity, and the cell cycle in A549 cells. Also, our study demonstrates that a microarray-based genomic survey is a suitable high-throughput approach for the evaluation of gene expression and for the characterization of TC-induced toxicity.

Gene expression profiles of human lung epithelial cells exposed to toluene

Allergic inflammatory diseases, such as asthma and allergic rhinitis, are caused by a complex interaction between genetic and environmental factors. Although several relevant candidate genes that are associated with environmental pollutants and allergic diseases have been identified in previous studies, the mechanisms underlying the induction of cytokines and chemokines by environmental pollutants and their role in human diseases are still unclear. This study examines the correlation between exposure to toluene, which is a common environmental pollutant, and the expression of immune-related genes, using reverse transcription-polymerase chain reaction (RT-PCR) with pathway-targeted arrays (RT2 Profiler™ PCR Arrays). Our PCR array analyses suggested the p38 MAPK and JNK pathways are activated upon toluene treatment in BEAS-2B cells, based on the expression profiles of MAPK8 (JNK1), MAPK9 (JNK2), MAPK10 (JNK3), MAPK11 (P38BETA2), CCL5 (RAN TES), CCL11 (eotaxin), and genes encoding proinflammatory cytokines, including tumor necrosis factor (TNF), TOLLIP, IL1A, and IL1B. This study aims to show that toluene exposure induces the expression of RANTES and eotaxin in cultured human bronchial epithelial cell lines through two distinct MAPKs, p38 and JNK.

Use of PCR-array to profile expressed genes in human keratinocyte hacat cells after exposure to Quantum Dots

Quantum dots (QDs) nanoparticles have potential applications in biomedical research, as imaging and diagnostic agents, because of their fluorescent property. Despite the widespread use of nanoparticles, there are many unknowns in understanding on their nanotoxicities and mechanisms. This study evaluated the effects of Quantum Dots (QDs) on gene expression profiles of human keratinocyte HaCaT cells. Total RNA was prepared from the exposure groups to QDs with diverse physicochemical properties (565-PEG-amine, 565-carboxylic acid, 655-carboxylic acid) in various concentrations, and real-time RT-PCR analysis was performed using human oxidative stress and antioxidant defense array. Our study indicated that antioxidant defense and oxidative stress category, such as nitric oxide synthase 2A (NOS2A), dual specificity phosphatase 1 (DUSP1), dual oxidase (DUOX), 24-dehydrocholesterol reductase (DHCR24), peroxidase in homolog (Drosophila)-like (PXDNL), scavenger receptor class A (SCARA3) and thyroid peroxidase (TPO), were represented by all three QDs exposure groups. Therefore, the up-regulation of these enzymes by QDs could increase the production of reactive oxygen species (ROS). The results of our study showed that QDs contained a potential to produce ROS via metabolic pathways, inducing oxidative stress. The results supported that the mechanism of nanotoxicity could be correlated with active oxygen production, oxidative stress, apoptosis, and antioxidant defense mechanisms.

Effect of toluene on RANTES and eotaxin expression through the p38 and JNK pathways in human lung epithelial cells

The increasing prevalence and severity of environmental diseases have been attributed the rise in environmental pollutants occurring as a consequence of industrial development. In this study, we examined that underlying mechanisms of toluene in human lung epithelial cells. We selected two genes known to be involved in environmental disease such as RANTES and eotaxin for the present study based on published reports and prior observation. We observed that toluene increased the mRNA and protein levels of RANTES and eotaxin in a dose-dependent manner, together with the activation of p38 MAPK and JNK. Moreover, the inhibition of p38 MAPK and JNK activation prevented the release of RANTES and eotaxin induced by toluene. The present study is the first to show that toluene exposure induces the expression of RANTES and eotaxin in human bronchial epithelial cells through two distinct MAPKs such as p38 and JNK. Our observations suggest that modulation of the expression of immunerelated chemokines and cytokines may be important factors in development of environmental diseases induced by air pollutants.

Assessment of phototoxicity, skin irritation, and sensitization potential of polystyrene and TiO2 nanoparticles

The human skin equivalent model (HSEM) is well known as an attractive alternative model for evaluation of dermal toxicity. However, only limited data are available on the usefulness of an HSEM for nanotoxicity testing. This study was designed to investigate cutaneous toxicity of polystyrene and TiO2 nanoparticles using cultured keratinocytes, an HSEM, and an animal model. In addition, we also evaluated the skin sensitization potential of nanoparticles using a local lymph node assay with incorporation of BrdU. Findings from the present study indicate that polystyrene and TiO2 nanoparticles do not induce phototoxicity, acute cutaneous irritation, or skin sensitization. Results from evaluation of the HSEMs correspond well with those from animal models. Our findings suggest that the HSEM might be a useful alternative model for evaluation of dermal nanotoxicity.