Sulfur mustard (SM) is a potent vesicant that targets epithelial cells and tissues. Most vesicant research has been performed using bona fide SM; however, some studies have used simulants, most notably half mustard (2-chloroethyl ethylsulfide; CEES) and nitrogen mustard (mechlorethamine; NM). Although CEES and NM have similarities to SM and can cause vesication, there are distinct differences in the chemical structures and physical properties of these compounds that may impact their toxic effects. Microarray analysis of cultured primary human epidermal keratinocytes (HEK) exposed to each of these vesicants was performed to directly compare the transcriptional responses induced by these vesicants. HEK were exposed in triplicate to concentrations ranging from 0-1000 M for SM and NM and 0-4000 M for CEES. Cells were harvested at 1, 2, 4, 8, 16, and 24 h and the RNA isolated for microarray analysis. Transcriptional responses were phenotypically anchored to cell morphology. The dataset was filtered by exposure and timepoint, and an analysis of variance was performed using dose as the factor. The top 500 genes ranked by p-value were analyzed using gene ontology algorithms to identify biological pathways significantly affected by each vesicant. At 2 h post-exposure, p53 signaling, Erk/MAPK signaling, and BMP signaling were significantly affected by all three vesicants. At 4 h post-exposure, p53 signaling , B cell activating factor, and glucocorticoid receptor signaling were significantly affected by all three vesicants. At 8 h post-exposure, there were no significant pathways commonly affected by all three vesicants. These results suggest that, although there are similarities in the transcriptional responses to each of these vesicants, the transcriptional responses appear to differ over time. Thus, extrapolation of results obtained with one vesicant to other vesicants may be complex and may have important implications for the development of vesicant therapeutics.
No associated publication
Specimen part
View SamplesOrganophosphorus nerve agents irreversibly inhibit acetylcholinesterase, causing a toxic buildup of acetylcholine at muscarinic and nicotinic receptors. Current medical countermeasures to nerve agent intoxication increase survival if administered within a short period of time following exposure but may not fully prevent neurological damage. Therefore, there is a need to discover drug treatments that are effective when administered after the onset of seizures and secondary responses that lead to brain injury. Methods To determine potential therapeutic targets for such treatments, we analyzed gene expression changes in the rat piriform cortex following sarin (O-isopropyl methylphosphonofluoridate) exposure. Male Sprague-Dawley rats were challenged with 1.0 x LD50 sarin and subsequently treated with atropine sulfate, 2-pyridine aldoxime methylchloride (2-PAM), and the anticonvulsant diazepam. Control animals received an equivalent volume of vehicle and drug treatments. The piriform cortex, a brain region particularly sensitive to neural damage from sarin-induced seizures, was extracted at 0.25, 1, 3, 6, and 24 h after seizure onset, and total RNA was processed for microarray analysis. Principal component analysis identified sarin-induced seizure occurrence and time point following seizure onset as major sources of variability within the dataset. Based on these variables, the dataset was filtered and analysis of variance was used to determine genes significantly changed in seizing animals at each time point. The calculated p-value and geometric fold change for each probeset identifier were subsequently used for gene ontology analysis to identify canonical pathways, biological functions, and networks of genes significantly affected by sarin-induced seizure over the 24-h time course. Results A multitude of biological functions and pathways were identified as being significantly altered following sarin-induced seizure. Inflammatory response and signaling pathways associated with inflammation were among the most significantly altered across the five time points examined. Conclusions This analysis of gene expression changes in the rat brain following sarin-induced seizure and the molecular pathways involved in sarin-induced neurodegeneration will allow a better identification of potential therapeutic targets for the development of effective neuroprotectants to treat nerve agent exposure.
No associated publication
Specimen part
View SamplesMale Sprague-dawley rats were exposed to saline, isopropyl alcohol, 1mg/kg, 3mg/kg or 6 mg/kg sulfur mustard for 30 min, 1 hr, 3 hr, 6 hr, or 24 hr before analysis of lung tissue by oligonucleotide array analysis.
Genomic analysis of rodent pulmonary tissue following bis-(2-chloroethyl) sulfide exposure.
No sample metadata fields
View SamplesBis-2-chloroethyl sulfide (sulfur mustard, SM) is a potent alkylating agent and vesicant. Exposure to SM results in activation of numerous signaling cascades, including mitogen-activated protein kinase (MAPK) signaling pathways. These pathways include the Erk, p38, and JNK pathways, which are involved in cell growth, inflammation, and stress signaling. However, the precise roles of these pathways in SM toxicity have not been fully elucidated. We used Western blotting and microarray analysis to examine the activation and role of each pathway following SM exposure in primary human epidermal keratinocytes. Western blotting revealed increased phosphorylation of p38 and JNK following SM exposure; however, phosphorylation of Erk was equivocal, suggesting that growth conditions may impact activation of Erk by SM. We used pharmacologic inhibitors to target each MAPK and then compared the gene expression profiles to identify SM-induced gene networks regulated by each MAPK. Cells were pretreated with 10 M SB 203580 (p38 inhibitor), PD 98059 (Erk inhibitor), or SP 600125 (JNK inhibitor) 60 minutes before exposure to 200 M SM. Cells were harvested at 1h, 4h, and 8h post-exposure, and RNA was extracted for synthesis of microarray probes. Probes were hybridized to Affymetrix U133 Plus 2.0 arrays for gene expression profiling. Analysis of variance was performed to identify genes significantly modulated due to pharmacologic inhibition in SM-exposed cells. Pathway mapping confirmed alterations in SM-induced Erk, JNK, and p38 MAPK signaling due to pharmacologic inhibition. SM-induced expression of IL-8, IL-6, and TNF-alpha was decreased by p38 MAPK inhibition, but not by inhibition of other MAPKs. Based on the number of significant pathways mapped to each MAPK in the presence and absence of inhibitors, the p38 MAPK pathway appeared to be the MAPK pathway most responsive to SM exposure. Interestingly, pathway mapping of the microarray data identified potential cross-talk between MAPK signaling pathways and other pathways involved in SM-induced signaling. Mining of these results will increase our understanding of the role of MAPK pathways in SM-induced signal transduction and may identify potential therapeutic targets for medical countermeasure development.
No associated publication
Specimen part
View SamplesCarbonyl chloride (phosgene) is a toxic industrial compound (TIC) widely used in industry for the production of synthetic products, such as polyfoam rubber, plastics, and dyes. Exposure to phosgene results in a latent (1-24 hr), potentially life-threatening pulmonary edema and irreversible acute lung injury. A genomic approach was utilized to investigate the molecular mechanism of phosgene-induced lung injury. CD-1 male mice were exposed whole-body to either air or a concentration x time (c x t) amount of 32 mg/m3 (8 ppm) phosgene for 20 min (640 mg x min/m3). Lung tissue was collected from air- or phosgene-exposed mice at 0.5, 1, 4, 8, 12, 24, 48, and 72 hr post-exposure. RNA was extracted from the lung and used as starting material for the probing of oligonucleotide microarrays to determine changes in gene expression following phosgene exposure. The data were analyzed using principal component analysis (PCA) to determine the greatest sources of data variability. A three-way analysis of variance (ANOVA) based on exposure, time, and sample was performed to identify the genes most significantly changed as a result of phosgene exposure. These genes were rank ordered by p-values and categorized based on molecular function and biological process. Some of the most significant changes in gene expression reflect changes in glutathione synthesis and redox regulation of the cell, including upregulation of glutathione S-transferase alpha-2, glutathione peroxidase 2, and glutamate-cysteine ligase, catalytic subunit (also known as -glutamyl cysteine synthetase). This is in agreement with previous observations describing changes in redox enzyme activity after phosgene exposure. We are also investigating other pathways that are responsive to phosgene exposure to identify mechanisms of toxicity and potential therapeutic targets.
Genomic analysis of murine pulmonary tissue following carbonyl chloride inhalation.
No sample metadata fields
View SamplesSulfur mustard (HD) is a potent alkylating agent that induces cutaneous injury. The molecular mechanisms of cutaneous injury are not completely understood, and the molecular pathways involved in post-exposure wound healing are not well characterized. To elucidate these molecular pathways for the purpose of identifying potential therapeutic targets, we used oligonucleotide microarrays to identify gene expression profile changes induced by HD in porcine skin, an established animal model of HD injury and wound healing. Female Yorkshire crossbred pigs were exposed to neat HD to generate a superficial dermal (second degree) injury. Skin punch biopsies were collected at 1 h, 2 h, 4 h, 24 h, 48 h, 72 h, 7 d, 14 d or 21 d post-exposure. Biopsies were scored for histopathology, and RNA extracted from biopsies was used for microarray analysis. Gene expression profiles were analyzed for significant temporal response to HD by analysis of variance (false discovery corrected p<0.05). Gene expression profiles were also correlated (Pearson linear correlation |r|>0.7, false discovery corrected p<0.05) to histopathology scores to identify molecular pathways significantly correlated with specific clinical endpoints of injury and repair. Several pathways linked to aspects of inflammatory response and cell cycle checkpoint regulation were altered by HD exposure through 72 h. Several of these inflammatory pathways were highly correlated with clinical endpoints assessed through 72 h, including epidermal necrosis and vesicle formation. Pathways linked to inflammation were also highly correlated with 7-21 d total histopathology scores, suggesting that inflammation is continual through the course of injury and healing. Specific therapeutic targets were identified within these inflammatory pathways, and potential therapeutics were also identified for future drug screening efforts.
No associated publication
Specimen part, Treatment
View SamplesRDX (Hexahydro-1,3,5-trinitro-1,3,5-triazine) is a synthetic, high-impact, relatively stable explosive that has been in use since WWII. Exposure to RDX can occur either occupationally or through ordnance that lays unexploded on training ranges. The toxicology of RDX is dominated by acute tonic-clonic seizures at high doses, which remit when exposure is removed and internal RDX levels decrease. Sub-chronic studies have revealed few other toxic effects. The objective of this study was to examine the effect of a single oral dose of RDX on global gene expression in the mammalian brain and liver, using a rodent model.
Global gene expression in rat brain and liver after oral exposure to the explosive hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX).
No sample metadata fields
View SamplesSoman (O-Pinacolyl methylphosphonofluoridate) is a potent neurotoxicant. Acute exposure to soman causes profound inhibition of the critical enzyme acetylcholinesterase, resulting in excessive levels of the neurotransmitter acetylcholine. Excessive acetylcholine levels cause convulsions, seizures, and respiratory distress. The initial cholinergic crisis can be overcome by rapid anti-cholinergic therapeutic intervention, resulting in increased survival. However, conventional treatments do not protect the brain from seizure-related damage, and thus neurodegeneration of soman-sensitive areas of the brain is a potential post-exposure outcome. We performed gene expression profiling of rat hippocampus following soman exposure to gain greater insight into the molecular pathogenesis of soman-induced neurodegeneration.
Gene expression profiling of rat hippocampus following exposure to the acetylcholinesterase inhibitor soman.
Sex
View SamplesNormal human epidermal keratinocytes (NHEKs) and HaCaTs have been widely used as cell culture models to study the effects of cutaneous sulfur mustard (HD) exposure. While these cell lines are similar, one key difference is that NHEKs are primary cells, whereas HaCaT cells are a transformed line with a mutation in the p53 gene. However, the impact of this mutation on the response of HaCaT cells to HD is unclear. Thus, gene expression profiling was performed to compare the transcriptional responses of NHEKs and HaCaTs after HD exposure. Cells were exposed to 0, 25, and 200 M HD, harvested at 1 h and 8 h post-exposure, and processed for microarray analysis. Principal component analysis of the microarray data suggested profile differences based on cell type, but both cell types respond similarly to HD with regard to dose and time. To further analyze the expression profiles at various doses, the dataset was filtered by dose, and an analysis of variance was performed using cell type as the factor; the pathways most significantly different between these cell types were identified. At all three doses, the p53 and N-glycan degradation pathways were significantly different between NHEKs and HaCaTs. Interestingly, p53 responsive genes showed differences and similarities across cell types, which may provide insight into the role of p53 in HD toxicity. The inflammatory pathways expected to respond to HD exposure were not significantly different between cell types, suggesting that both NHEKs and HaCaTs are appropriate models to study the inflammatory effects of HD.
No associated publication
Specimen part, Time
View SamplesGene expression profiling is an important tool in the development of medical countermeasures against chemical warfare agents (CWAs). Non-human primates (NHPs), specifically the rhesus macaque (Macaca mulatta), the cynomologus macaque (Macaca fascicularis) and the African green monkey (Chlorocebus aethiops), are vital models in the development of CWA prophylactics, therapeutics, and diagnostics. However, gene expression profiling of these NHPs is complicated by the fact their genomes are not completely sequenced, and that no commercially available oligonucleotide microarrays (genechips) exist. We, therefore, sought to determine whether gene expression profiling of NHPs could be performed using human genechips. Whole blood RNA was isolated from each species and used to generate genechip probes. Hybridization of the NHP samples to human genechips (Affymetrix Human U133 Plus 2.0) resulted in comparable numbers of transcripts detected compared with human samples. Statistical analysis revealed intraspecies reproducibility of genechip quality control metrics; interspecies comparison between NHPs and humans showed little significant difference in the quality and reproducibility of data generated using human genechips. Expression profiles of each species were compared using principal component analysis (PCA) and hierarchical clustering to determine the similarity of the expression profiles within and across the species. The cynomologus group showed the least intraspecies variability, while the human group showed the greatest intraspecies variability. Intraspecies comparison of the expression profiles identified probesets that were reproducibly detected within each species. Each NHP species was found to be dissimilar to humans; the cynomologus group was the most dissimilar. Interspecies comparison of the expression profiles revealed probesets that were reproducibly detected in all species examined. These results show that human genechips can be used for expression profiling of NHP samples and provide a foundation for the development of tools for comparing human and NHP gene expression profiles.
Comparison of non-human primate and human whole blood tissue gene expression profiles.
No sample metadata fields
View Samples