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Toxicogenomic identification of biomarkers of acute respiratory expsoure to sensitizing agents
Citation:
PUCHEU-HASTON, C. M., L. B. COPELAND, E. BOYKIN, AND M. D. WARD. Toxicogenomic identification of biomarkers of acute respiratory expsoure to sensitizing agents. Presented at Society of Toxicology 49th annual meeting , Salt Lake City, UT, March 07 - 11, 2010.
Impact/Purpose:
This abstract describes a research effort to identify biomarkers that differentiate the responses to allergens vs. non-allergens following an acute exposure. Biomarker genes obtained from this analysis will facilitate improvements in methods of screening for respiratory sensitizers.
Description:
Allergy induction requires multiple exposures to an agent. Therefore the development of high-throughput or in vitro assays for effective screening of potential sensitizers will require the identification of biomarkers. The goal of this preliminary study was to identify potential biomarkers that differentiate the response to allergen vs non-allergen agents following an acute exposure in natve individuals. Female BALB/c mice received a single intratracheal aspiration exposure to Metarhizium anisopliae crude antigen (MACA) or bovine serum albumin (BSA) in Hank's Balanced Salt Solution (HBSS) or HBSS alone. Mice were sacrificed after 1, 3, 6, 12, 18 and 24h. Bronchoalveolar lavage fluid (BALF) was evaluated to determine total and differential cellularity, total protein concentration and LDH activity. RNA was isolated from lung tissue for microarray . analysis and RT-PCR. MACA administration induced a rapid increase in BALF neutrophils, lymphocytes, eosinophils and total protein levels as compared to BSA or HBSS. Microarray analysis demonstrated differential expression of genes involved in cytokine production, signaling, inflammatory cell recruitment, adhesion and activation in 3h and 12h MACA-treated samples as compared to BSA or HBSS. Further statistical and pathway analyses allowed identification of -100 candidate biomarker genes. Eleven genes were selected for further assessment by qRT-PCR. Of these, 6 demonstrated persistently increased expression (Ccl17, Ccl22, Cc17, Cxc110, Cxcl2, Saa1), while C3ar1 increased from 6-24h. In conclusion, a single respiratory exposure of mice to an allergenic mold extract induces an inflammatory response which is distinct in phenotype and gene expression from the response to a control protein. Validation of these biomarker genes with additional allergens and irritants is in progress. Biomarkers identified in these analyses will facilitate improvements in screening methods. (Supported by UNC/EPA Cooperative Training Agreement CR83323701. This abstract does not reflect EPA policy).