Carbonyl chloride (phosgene) is a toxic industrial compound 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 h), 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 × time amount of 32 mg/m3 (8 ppm) phosgene for 20 min (640 mg × min/m3). Lung tissue was collected from air- or phosgene-exposed mice at 0.5, 1, 4, 8, 12, 24, 48, and 72 h postexposure. 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 to determine the greatest sources of data variability. A three-way analysis of variance 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 α-2, glutathione peroxidase 2, and glutamate-cysteine ligase, catalytic subunit (also known as γ-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.

Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing this collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden to Department of Defense, Washington Headquarters Services, Directorate for Information Bis-(2-chloroethyl) sulfide (sulfur mustard, SM) is a carcinogenic alkylating agent that has been utilized as a chemical warfare agent. To understand the mechanism of SM-induced lung injury, we analyzed global changes in gene expression in a rat lung SM exposure model. Rats were injected in the femoral vein with liquid SM, which circulates directly to the pulmonary vein and then to the lung. Rats were exposed to 1, 3, or 6 mg/kg of SM, and lungs were harvested at 0.5, 1, 3, 6, and 24 h postinjection. Three biological replicates were used for each time point and dose tested. RNA was extracted from the lungs and used as the starting material for the probing of replicate oligonucleotide microarrays. The gene expression data were analyzed using principal component analysis and two-way analysis of variance to identify the genes most significantly changed across time and dose. These genes were ranked byp value and categorized based on molecular function and biological process. Computer-based data mining algorithms revealed several biological processes affected by SM exposure, including protein catabolism, apoptosis, and glycolysis. Several genes that are significantly upregulated in a dose-dependent fashion have been reported as p53 responsive genes, suggesting that cell cycle regulation and p53 activation are involved in the response to SM exposure in the lung. Thus, SM exposure induces transcriptional changes that reveal the cellular response to this potent alkylating agent. Introductionmodification of DNA by SM has been well-characterized Bis-(2-chloroethyl) sulfide (sulfur mustard, SM)1-3 is due to the use of SM and related molecules as anticancer a carcinogen and chemical warfare agent that was used therapies (1), and covalent modification of proteins by on the battlefield during World War I and has since been SM has also been demonstrated (2-5). A variety of used in several conflicts around the globe. SM exposure molecular targets and pathways have been implicated in usedin eveal cnflctsaroud te gobe.SM xpoure the mechanism of toxicity of SM exposure (1); however, results in cutaneous, pulmonary, and ocular injury. th e mechanism s of cexposuremain;undeDespite much research, an effective medical countermeathe precise mechanisms of cellular injury remain undesure for SM exposure has not been developed because lineated. the molecular mechanism of SM toxicity is not wellThe lung is a primary target of SM vapor. Inhalation understood. SM is a potent alkylating agent capable of exposure causes pulmonary...

Bis-(2-chloroethyl) sulfide (sulfur mustard; SM) is a potent alkylating agent. Three treatment compounds have been shown to limit SM damage in the mouse ear vesicant model: dimercaprol, octyl homovanillamide, and indomethacin. Microarrays were used to determine gene expression profiles of biopsies taken from mouse ears after exposure to SM in the presence or absence of treatment compounds. Mouse ears were topically exposed to SM alone or were pretreated for 15 min with a treatment compound and then exposed to SM. Ear tissue was harvested 24 h after exposure for ear weight determination, the endpoint used to evaluate treatment compound efficacy. RNA extracted from the tissues was used to generate microarray probes for gene expression profiling of therapeutic responses. Principal component analysis of the gene expression data revealed partitioning of the samples based on treatment compound and SM exposure. Patterns of gene responses to the treatment compounds were indicative of exposure condition and were phenotypically anchored to ear weight. Pretreatment with indomethacin, the least effective treatment compound, produced ear weights close to those treated with SM alone. Ear weights from animals pretreated with dimercaprol or octyl homovanillamide were more closely associated with exposure to vehicle alone. Correlation coefficients between gene expression level and ear weight revealed genes involved in mediating responses to both SM exposure and treatment compounds. These data provide a basis for elucidating the mechanisms of response to SM and drug treatment and also provide a basis for developing strategies to accelerate development of effective SM medical countermeasures.Bis-(2-chloroethyl) sulfide (sulfur mustard; SM) is a potent bifunctional alkylating agent capable of modifying and crosslinking cellular macromolecules such as DNA and protein by nucleophilic attack (Papirmeister et al., 1991). SM exposure can produce debilitating pulmonary, ocular, and cutaneous injuries. After cutaneous exposure to SM, there is a dosedependent latent phase of 8 to 24 h that precedes clinical expression of tissue damage. Erythema occurs initially and is followed by vesication because of separation at the epidermal-dermal junction. This results in large fluid-filled lesions that are long-lasting and slow to heal (Papirmeister et al., 1991;Petrali and Oglesby-Megee, 1997). The formation of blisters is accompanied by a potent inflammatory response, observed as increased production of inflammatory mediators and infiltration of the exposure area by activated immune cells (Rikimaru et al