Biomedical subjects

Dori R Germolec

Publications and source records attributed to Dori R Germolec.

At least 19 recordsLinked to original sources

PubMed2006

Spontaneous airway hyperresponsiveness in estrogen receptor-alpha-deficient mice.

RATIONALE: Airway hyperresponsiveness is a critical feature of asthma. Substantial epidemiologic evidence supports a role for female sex hormones in modulating lung function and airway hyperresponsiveness in humans. OBJECTIVES: To examine the role of estrogen receptors in modulating lung function and airway responsiveness using estrogen receptor-deficient mice. METHODS: Lung function was assessed by a combination of whole-body barometric plethysmography, invasive measurement of airway resistance, and isometric force measurements in isolated bronchial rings. M2 muscarinic receptor expression was assessed by Western blotting, and function was assessed by electrical field stimulation of tracheas in the presence/absence of gallamine. Allergic airway disease was examined after ovalbumin sensitization and exposure. MEASUREMENTS AND MAIN RESULTS: Estrogen receptor-alpha knockout mice exhibit a variety of lung function abnormalities and have enhanced airway responsiveness to inhaled methacholine and serotonin under basal conditions. This is associated with reduced M2 muscarinic receptor expression and function in the lungs. Absence of estrogen receptor-alpha also leads to increased airway responsiveness without increased inflammation after allergen sensitization and challenge. CONCLUSIONS: These data suggest that estrogen receptor-alpha is a critical regulator of airway hyperresponsiveness in mice.

Acetylcholine↗

PubMed2006

Immunotoxicogenomics: the potential of genomics technology in the immunotoxicity risk assessment process.

Evaluation of xenobiotic-induced changes in gene expression as a method to identify and classify potential toxicants is being pursued by industry and regulatory agencies worldwide. A workshop was held at the Research Triangle Park campus of the Environmental Protection Agency to discuss the current state-of-the-science of "immunotoxicogenomics" and to explore the potential role of genomics techniques for immunotoxicity testing. The genesis of the workshop was the current lack of widely accepted triggering criteria for Tier 1 immunotoxicity testing in the context of routine toxicity testing data, the realization that traditional screening methods would require an inordinate number of animals and are inadequate to handle the number of chemicals that may need to be screened (e.g., high production volume compounds) and the absence of an organized effort to address the state-of-the-science of toxicogenomics in the identification of immunotoxic compounds. The major focus of the meeting was on the theoretical and practical utility of genomics techniques to (1) replace or supplement current immunotoxicity screening procedures, (2) provide insight into potential modes or mechanisms of action, and (3) provide data suitable for immunotoxicity hazard identification or risk assessment. The latter goal is of considerable interest to a variety of stakeholders as a means to reduce animal use and to decrease the cost of conducting and interpreting standard toxicity tests. A number of data gaps were identified that included a lack of dose response and kinetic data for known immunotoxic compounds and a general lack of data correlating genomic alterations to functional changes observed in vivo. Participants concluded that a genomics approach to screen chemicals for immunotoxic potential or to generate data useful to risk assessors holds promise but that routine use of these methods is years in the future. However, recent progress in molecular immunology has made mode and mechanism of action studies much more practical. Furthermore, a variety of published immunotoxicity studies suggest that microarray analysis is already a practical means to explore pathway-level changes that lead to altered immune function. To help move the science of immunotoxicogenomics forward, a partnership of industry, academia, and government was suggested to address data gaps, validation, quality assurance, and protocol development.

Animals↗

PubMed2006

Gene expression alterations in immune system pathways following exposure to immunosuppressive chemicals.

Exposure to environmental agents can affect a number of adverse immunological outcomes, including changes in the incidence of infectious disease. Diethylstilbestrol (DES), dexamethasone (DEX), cyclophosphamide, and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) are immunosuppressive chemicals that can induce similar pathophysiological end points in the thymus; however, the mechanism of toxicity is different for each compound. We examined differential gene expression in the spleen and thymus following chemical exposure and correlated these changes with alterations in functional immune end points and our knowledge of the known mechanisms of action. RNA from the spleen and thymus has been analyzed using Illumina Sentrix arrays and BeadStudio software. Preliminary data suggest that DES induced the greatest number of gene changes in the spleen, while DEX induced the most changes in the thymus. In both spleen and thymus, genomic analysis revealed gene expression changes that were common to multiple chemicals and that may be associated with xenobiotic-induced immune system perturbations, including alterations in genes associated with apoptosis, antigen processing and presentation, and response to biotic stimulus. This was particularly evident in the thymus, where there were many similarities in the expression profiles, as well as gene alterations unique to a single compound. In contrast, expression profiles in spleen were more distinct. The category of genes most profoundly affected by all four chemicals was response to biotic stimulus: there were both clusters of genes modulated by multiple chemicals and genes altered by a single chemical. The distinct gene profiles may specifically relate to cellular targets and mechanism of action.

Animals↗

PubMed2006

Induction of asthma and the environment: what we know and need to know.

The prevalence of asthma has increased dramatically over the last 25 years in the United States and in other nations as a result of ill-defined changes in living conditions in modern society. On 18 and 19 October 2004 the U.S. Environmental Protection Agency and the National Institute of Environmental Health Sciences sponsored the workshop "Environmental Influences on the Induction and Incidence of Asthma" to review current scientific evidence with respect to factors that may contribute to the induction of asthma. Participants addressed two broad questions: a) What does the science suggest that regulatory and public health agencies could do now to reduce the incidence of asthma? and b) What research is needed to improve our understanding of the factors that contribute to the induction of asthma and our ability to manage this problem? In this article (one of four articles resulting from the workshop), we briefly characterize asthma and its public health and economic impacts, and intervention strategies that have been successfully used to prevent induction of asthma in the workplace. We conclude with the findings of seven working groups that focus on ambient air, indoor pollutants (biologics), occupational exposures, early life stages, older adults, intrinsic susceptibility, and lifestyle. These groups found strong scientific support for public health efforts to limit in utero and postnatal exposure to cigarette smoke. However, with respect to other potential types of interventions, participants noted many scientific questions, which are summarized in this article. Research to address these questions could have a significant public health and economic impact that would be well worth the investment.

Adolescent↗

PubMed2005

Thalidomide enhances both primary and secondary host resistances to Listeria monocytogenes infection by a neutrophil-related mechanism in female B6C3F1 mice.

Previously, we have reported that thalidomide can modulate the immune responses in female B6C3F1 mice. Furthermore, thalidomide immunomodulation increased primary host resistance to intravenously infected Listeria monocytogenes. The present study was intended to evaluate the mechanisms underlying the enhanced host resistance to L. monocytogenes by focusing on the neutrophils. Female B6C3F1 mice were treated intraperitoneally with thalidomide (100 mg/kg) for 15 days. Exposure to thalidomide increased the numbers of neutrophils in the spleens and livers of L. monocytogenes-infected mice when compared to the L. monocytogenes-infected control mice. Additionally, the percentage of neutrophils was also significantly increased after Thd treatment in L. monocytogenes-infected mice. Further studies using antibodies to deplete corresponding cells indicated that thalidomide-mediated increase in primary host resistance (both the moribundity and colony counts in the liver and spleen) to L. monocytogenes infection was due to its effect on neutrophils but not CD8+ T cells or NK cells. Finally, Thd exposure also increased host resistance to secondary host resistance to L. monocytogenes infection, and depletion of neutrophils abolished the protective effect. In conclusion, thalidomide enhanced host resistance to both primary and secondary L. monocytogenes infections by a neutrophil-related mechanism in female B6C3F1 mice.

Animals↗

PubMed2005

Contrasting effects of cyclooxygenase-1 (COX-1) and COX-2 deficiency on the host response to influenza A viral infection.

Influenza is a significant cause of morbidity and mortality worldwide despite extensive research and vaccine availability. The cyclooxygenase (COX) pathway is important in modulating immune responses and is also a major target of nonsteroidal anti-inflammatory drugs (NSAIDs) and the newer COX-2 inhibitors. The purpose of the present study was to examine the effect of deficiency of COX-1 or COX-2 on the host response to influenza. We used an influenza A viral infection model in wild type (WT), COX-1-/-, and COX-2-/- mice. Infection induced less severe illness in COX-2-/- mice in comparison to WT and COX-1-/- mice as evidenced by body weight and body temperature changes. Mortality was significantly reduced in COX-2-/- mice. COX-1-/- mice had enhanced inflammation and earlier appearance of proinflammatory cytokines in the BAL fluid, whereas the inflammatory and cytokine responses were blunted in COX-2-/- mice. However, lung viral titers were markedly elevated in COX-2-/- mice relative to WT and COX-1-/- mice on day 4 of infection. Levels of PGE2 were reduced in COX-1-/- airways whereas cysteinyl leukotrienes were elevated in COX-2-/- airways following infection. Thus, deficiency of COX-1 and COX-2 leads to contrasting effects in the host response to influenza infection, and these differences are associated with altered production of prostaglandins and leukotrienes following infection. COX-1 deficiency is detrimental whereas COX-2 deficiency is beneficial to the host during influenza viral infection.

Animals↗

PubMed2005

Maternal treatment with a high dose of CpG ODN during gestation alters fetal craniofacial and distal limb development in C57BL/6 mice.

Synthetic oligodeoxynucleotides (ODN) containing CpG motifs, characteristic of bacterial DNA, are currently being evaluated as vaccine adjuvants for inducing protective immunity. Recently, there is increasing pressure to vaccinate pregnant women against maternally transmitted diseases including AIDS and tetanus, as well as against potential bio-weapons such as anthrax. CpG vaccines are effective because they trigger transient increases in T(H)1 cytokine production. Recent literature suggests, however, that a shift toward a T(H)1 cytokine profile during pregnancy may increase the risk of fetal morphologic defects. On this basis, we hypothesized that exposure to CpG motifs during pregnancy could result in T(H)1 inflammation leading to adverse effects on fetal development. To address this hypothesis, pregnant C57BL/6 mice were injected with CpG ODN (0-300 microg/dam) and maternal and fetal outcomes were determined. Injection of dams with the highest dose of CpG ODN resulted in markedly increased fetal resorptions and craniofacial/limb defects, while lower doses had little, if any effects. Histological examination of placentas revealed cellular necrosis with mixed inflammation and calcification in the spongiotrophoblast layer and dysregulation of labyrinthine vascular development. Concomitant elevations in maternal serum cytokine levels were observed including interleukin (IL)-2, IL-10 and IL-12. Treatment with 300 microg of non-CpG ODN did not cause any adverse effects. The 300 microg dose of CpG ODN used in the present study is 30-fold higher than the highest dose that has been administered to humans during clinical trials. These results suggest that the induction of T(H)1 cytokines during pregnancy by CpG motifs may potentially increase the risk of fetal loss and morphologic defects in mice, at least at high doses, and support the need for further investigation of teratogenesis that may result from exposure to vaccine adjuvants designed to produce T(H)1 cytokine profile shifts.

Animals↗

PubMed2005

Stimulation of the immune response in B6C3F1 mice by genistein is affected by exposure duration, gender, and litter order.

The objective of this study was to determine whether immune responses could be differentially modulated by the phytoestrogen genistein (GEN) in mice from the 1st and 2nd litters, and whether the effects were persistent or reversible. B6C3F1 mice were exposed to a control or GEN-containing diet at 25, 250, and 1250 microg/g for the 1st litters, and 500 microg/g for the 2nd litters from d 0 of gestation to postnatal day (PND) 22, and through feeding after weaning. At PND42, anti-CD3 antibody-stimulated splenic T-cell proliferation and the percentages of T cells were increased in mice from the 1st litters at 250 and 1250 microg/g GEN but not from the 2nd litters. At PND84, the activity of IL-2-treated NK cells was significantly increased by GEN in mice from the 2nd litters but not from the 1st litters. The activity of cytotoxic T cells (CTLs) was also significantly increased by GEN in male mice from the 2nd litters. However, the increases in the CTL activity were not significant when the male mice were shifted from GEN-containing food to control food at PND22. Additionally, the increases in T-cell activities in female mice from the 1st litters and male mice from the 2nd litters were associated with a decrease in the percentage of CD4+CD25+ T regulatory cells. Overall, the results demonstrated that GEN could enhance the immune responses in mice from the 1st and 2nd litters; however, the effects varied depending on the exposure duration, gender, and litter order.

Animal Feed↗

PubMed2004

Associations between plasma DDE levels and immunologic measures in African-American farmers in North Carolina.

Experimental studies in rodents demonstrate evidence of immunosuppressive effects of dietary exposure to DDT [2,2-bis((italic)p(/italic)-chlorophenyl)-1,1,1-trichloroethane], but human data pertaining to immunomodulating effects of DDT exposure are limited. In this study we examined the association between the persistent organochlorine breakdown product 1,1-dichloro-2,2,bis(p-chlorophenyl)ethylene p,p'-DDE) and immunologic measures using blood samples in a relatively highly exposed population of farmers in the United States. Levels of serum immunoglobulin A (IgA) and IgG and the prevalence of antinuclear antibodies in relation to plasma p,p'-DDE levels were evaluated in samples from 137 African-American male farmers (30-88 years of age; median, 64 years). Participants were recruited through black churches in four rural counties in eastern North Carolina. Data collection included a telephone interview pertaining to farming practices and health history, and one blood sample was collected from each participant. Linear and logistic regression, adjusting for age, cholesterol, triglycerides, smoking status, and years of any kind of pesticide use, was used to assess the association between immunologic parameters and plasma levels of p,p'-DDE. The median plasma p,p'-DDE concentration was 7.7 microg/L (range, 0.6-77.4 microg/L). There was no association between p,p'-DDE and IgA in any of the models. IgG levels decreased with increasing p,p'-DDE levels, with a statistically significant decrease of approximately 50% in the highest two categories of exposure (greater than or equal to 6.0 microg/L) compared with values of < 3.0 microg/L. Sixteen (12%) were positive for antinuclear antibodies. The prevalence of antinuclear antibodies was somewhat elevated in the highest category of p,p'-DDE exposure (odds ratio, 1.9; 95% confidence interval, 0.32-11.3; for > or = 12.0 microg/L compared with < 3.0 microg/L p,p'-DDE), but this difference was not statistically significant. These analyses provide evidence that p,p'-DDE modulates immune responses in humans.

Adult↗

PubMed2004

Biokinetics and subchronic toxic effects of oral arsenite, arsenate, monomethylarsonic acid, and dimethylarsinic acid in v-Ha-ras transgenic (Tg.AC) mice.

Previous research demonstrated that 12-O-tetradecanoylphorbol-13-acetate (TPA) treatment increased the number of skin papillomas in v-Ha-ras transgenic (Tg.AC) mice that had received sodium arsenite [(As(III)] in drinking water, indicating that this model is useful for studying the toxic effects of arsenic in vivo. Because the liver is a known target of arsenic, we examined the pathophysiologic and molecular effects of inorganic and organic arsenical exposure on Tg.AC mouse liver in this study. Tg.AC mice were provided drinking water containing As(III), sodium arsenate [As(V)], monomethylarsonic acid [(MMA(V)], and 1,000 ppm dimethylarsinic acid [DMA(V)] at dosages of 150, 200, 1,500, or 1,000 ppm as arsenic, respectively, for 17 weeks. Control mice received unaltered water. Four weeks after initiation of arsenic treatment, TPA at a dose of 1.25 microg/200 microL acetone was applied twice a week for 2 weeks to the shaved dorsal skin of all mice, including the controls not receiving arsenic. In some cases arsenic exposure reduced body weight gain and caused mortality (including moribundity). Arsenical exposure resulted in a dose-dependent accumulation of arsenic in the liver that was unexpectedly independent of chemical species and produced hepatic global DNA hypomethylation. cDNA microarray and reverse transcriptase-polymerase chain reaction analysis revealed that all arsenicals altered the expression of numerous genes associated with toxicity and cancer. However, organic arsenicals [MMA(V) and DMA(V)] induced a pattern of gene expression dissimilar to that of inorganic arsenicals. In summary, subchronic exposure of Tg.AC mice to inorganic or organic arsenicals resulted in toxic manifestations, hepatic arsenic accumulation, global DNA hypomethylation, and numerous gene expression changes. These effects may play a role in arsenic-induced hepatotoxicity and carcinogenesis and may be of particular toxicologic relevance.

Administration, Oral↗

PubMed2003

Octamethylcyclotetrasiloxane exhibits estrogenic activity in mice via ERalpha.

Octamethylcyclotetrasiloxane (D4) is a low molecular weight cyclic silicone used in the synthesis of larger silicone polymers and in the formulation of a variety of personal care products. The effects of oral D4 exposure in mice on serum estradiol levels, uterine wet weight, and uterine peroxidase activity were investigated. Additionally, in vitro estrogen receptor binding activity was evaluated. Serum estradiol levels decreased in a dose-dependent manner after exposure to 100 mg/kg to 1000 mg/kg D4. Studies with adrenalectomized animals demonstrated that the decreased serum estradiol levels were not due to elevated serum corticosterone levels. Uterine wet weights in ovariectomized mice were significantly increased in a dose-dependent manner by exposure to 250-1000 mg of D4/kg, but not by exposure to other silicone compounds tested (hexamethylcyclotrisiloxane, decamethylcyclopentasiloxane, decamethyltetrasiloxane, and octaphenylcyclotetrasiloxane). Uterine peroxidase activity, a marker for estrogenic activity, was also significantly increased in D4-exposed mice, but not in mice exposed to the other siloxanes. Pretreating mice with the estrogen receptor antagonist ICI 182,780 completely blocked the D4-induced increase in uterine weight, and ovariectomized estrogen receptor-alpha knockout mice showed no increases in uterine weights when orally exposed to D4 or estradiol. In an in vitro estrogen receptor binding assay, D4 showed significant competition with (3)H-estradiol for binding to estrogen receptor-alpha, but not estrogen receptor-beta. The data presented here indicate that D4 has weak estrogenic activity, and that these effects are mediated through estrogen receptor-alpha.

Adjuvants, Immunologic↗

PubMed2003

Accentuated T helper type 2 airway response after allergen challenge in cyclooxygenase-1-/- but not cyclooxygenase-2-/- mice.

Acute pharmacologic inhibition of cyclooxygenase (COX)-1 or -2 during allergen sensitization and exposure leads to enhanced T helper type 2 (Th2) airway responses. COX-1 and -2 play functionally distinct roles in lymphocyte development, and consequently, genetic deficiency of either enzyme, as opposed to acute pharmacologic inhibition, may modulate Th2-mediated allergic airway disease differently. An ovalbumin-induced mouse model of allergic airway disease was used. The immunophenotype of bronchoalveolar lavage lymphocytes was assessed by flow cytometry, bronchoalveolar lavage cytokines, and chemokines were measured by enzyme-linked immunosorbent assay, adhesion molecule expression was assessed by immunoblotting in combination with immunohistochemistry, and bronchoconstriction was assessed by whole body plethysmography. The airways of COX-1-/- mice contained increased numbers of CD4+ and CD8+ T cells, exaggerated levels of the Th2 cytokines interleukin-4, -5, and -13, and increased levels of eotaxin and thymus- and activation-regulated chemokine. Allergen-induced bronchoconstriction was also increased in COX-1-/- mice. Vascular cell adhesion molecule-1 and intercellular adhesion molecule-1 levels were increased in lungs of both COX-1-/- and COX-2-/- mice relative to wild type. These data suggest that genetic deficiency of COX-1 but not COX-2 modulates T cell recruitment, Th2 cytokine secretion, and lung function in the allergic airway.

Allergens↗

PubMed2003

Key issues for the assessment of the allergenic potential of genetically modified foods: breakout group reports.

On the final afternoon of the workshop "Assessment of the Allergenic Potential of Genetically Modified Foods," held 10-12 December 2001 in Chapel Hill, North Carolina, USA, speakers and participants met in breakout groups to discuss specific questions in the areas of use of human clinical data, animal models to assess food allergy, biomarkers of exposure and effect, sensitive populations, dose-response assessment, and postmarket surveillance. Each group addressed general questions regarding allergenicity of genetically modified foods and specific questions for each subject area. This article is a brief summary of the discussions of each of the six breakout groups regarding our current state of knowledge and what information is needed to advance the field.

Biomarkers↗

PubMed2003

Assessment of allergenic potential of genetically modified foods: an agenda for future research.

Speakers and participants in the workshop "Assessment of the Allergenic Potential of Genetically Modified Foods" met in breakout groups to discuss a number of issues including needs for future research. These groups agreed that research should progress quickly in the area of hazard identification and that a need exists for more basic research to understand the mechanisms underlying food allergy. A list of research needs was developed.

Animals↗

PubMed2003

Consensus workshop on methods to evaluate developmental immunotoxicity.

A workshop cosponsored by the National Institute of Environmental Health Sciences and the National Institute for Occupational Safety and Health was convened in Washington, DC, on 17-18 October 2001 with the goal of developing a consensus document on the most appropriate experimental approaches and assays available to assess developmental immunotoxicity. The work group was composed of scientists from academia, the chemical and pharmaceutical industries, and federal agencies with expertise in developmental immunology, developmental toxicology, immunotoxicology, and risk evaluation. This consensus document presents an overview of the major summations made by the work group. A summary of early work in the field is provided, which includes potential immunotoxic agents, followed by brief discussions of our current understanding of developmental immunology. This report concludes with the work group's consensus of the most appropriate experimental design and tests to screen for potential developmental immunotoxic agents in experimental models, including potential limitations and data gaps.

Environmental Pollutants↗

PubMed2002

Occupational exposures and autoimmune diseases.

Autoimmune diseases are pathologic conditions defined by abnormal autoimmune responses and characterized by immune system reactivity in the form of autoantibodies and T cell responses to self-structures. Here we review the limited but growing epidemiologic and experimental literature pertaining to the association between autoimmune diseases and occupational exposure to silica, solvents, pesticides, and ultraviolet radiation. The strongest associations (i.e., relative risks of 3.0 and higher) have been documented in investigations of silica dust and rheumatoid arthritis, lupus, scleroderma and glomerulonephritis. Weaker associations are seen, however, for solvent exposures (in scleroderma, undifferentiated connective tissue disease, and multiple sclerosis) and for farming or pesticide exposures (in rheumatoid arthritis). Experimental studies suggest two different effects of these exposures: an enhanced proinflammatory (TH1) response (e.g., TNF-alpha and IL-1 cytokine production with T cell activation), and increased apoptosis of lymphocytes leading to exposure to or modification of endogenous proteins and subsequent autoantibody formation. The former is a general mechanism that may be relevant across a spectrum of autoimmune diseases, whereas the latter may be a mechanism more specific to particular diseases (e.g., ultraviolet radiation, Ro autoantibodies, and lupus). Occupational exposures are important risk factors for some autoimmune diseases, but improved exposure assessment methods and better coordination between experimental/animal models and epidemiologic studies are needed to define these risks more precisely.

Animals↗

PubMed2002

Oxidative stress and its role in skin disease.

Skin is a major target of oxidative stress due to reactive oxygen species (ROS) that originate in the environment and in the skin itself. ROS are generated during normal metabolism, are an integral part of normal cellular function, and are usually of little harm because of intracellular mechanisms that reduce their damaging effects. Antioxidants attenuate the damaging effects of ROS and can impair and/or reverse many of the events that contribute to epidermal toxicity and disease. However, increased or prolonged free radical action can overwhelm ROS defense mechanisms, contributing to the development of cutaneous diseases and disorders. Although ROS play a role in diseases such as skin cancer, their biological targets and pathogenic mode of action are still not fully understood. In addition, strategies useful in the therapeutic management of ROS action in human skin are still lacking. This review is intended to give investigators an introduction to ROS, antioxidants, two skin disorders influenced by ROS action (skin cancer and psoriasis), and relevant model systems used to study ROS action.

Animals↗

PubMed2002

Sodium arsenite-induced stress-related gene expression in normal human epidermal, HaCaT, and HEL30 keratinocytes.

Arsenic is a carcinogen that poses a significant health risk in humans. Based on evidence that arsenic has differential effects on human, rodent, normal, and transformed cells, these studies addressed the relative merits of using normal human epidermal keratinocytes (NHEK) and immortalized human (HaCaT) and mouse (HEL30) keratinocytes when examining stress-induced gene expression that may contribute to carcinogenesis. We hypothesize that redox-related gene expression is differentially modulated by arsenic in normal versus immortalized keratinocytes. To test the hypothesis, we exposed keratinocytes to sodium arsenite for 4 or 24 hr, at which time serine threonine kinase-25 (stk25) and nicotine adenine dinucleotide phosphate [nad(p)h] quinone oxidoreductase gene expression were measured. The effect of glutathione reduction on arsenite-induced cytotoxicity and gene expression in NHEK also was evaluated by addition of l-buthionine-[S,R]-sulfoximine (BSO) to culture media. Results indicate the term LC(50) for arsenite is approximately 10-15 microM in NHEK and HEL30 keratinocytes and 30 microM in HaCaT keratinocytes. Compared with HaCaT and HEL30 keratinocytes, a nontoxic concentration of arsenite (2.5 microM) increases stk25 and nad(p)h quinone oxidoreductase gene expression in NHEK, an effect partially attenuated by BSO. These data indicate that NHEK and HaCaT/HEL30 keratinocytes have similar sensitivities toward arsenite-induced cytotoxicity but unique gene expression responses. They also suggest that arsenite modulates gene expression in NHEK involved in cellular signaling and other aspects of intermediary metabolism that may contribute to the carcinogenic process.

Animals↗