Abstract
Hyperoxia contributes to lung injury in experimental animals and diseases such as acute respiratory distress syndrome in humans. Cytochrome P450 (CYP)1A enzymes are protective against hyperoxic lung injury (HLI). The molecular pathways and differences in gene expression that modulate these protective effects remain largely unknown. Our objective was to characterize genotype specific differences in the transcriptome and proteome of acute hyperoxic lung injury using the omics platforms: microarray and Reverse Phase Proteomic Array. Wild type (WT), Cyp1a1-/- and Cyp1a2-/- (8-10 wk, C57BL/6J background) mice were exposed to hyperoxia (FiO2 > 0.95) for 48 hours. Comparison of transcriptome changes in hyperoxia-exposed animals (WT versus knock-out) identified 171 genes unique to Cyp1a1-/- and 119 unique to Cyp1a2-/- mice. Gene Set Enrichment Analysis revealed pathways including apoptosis, DNA repair and early estrogen response that were differentially regulated between WT, Cyp1a1-/- and Cyp1a2-/- mice. Candidate genes from these pathways were validated at the mRNA and protein level. Quantification of oxidative DNA adducts with 32P-postlabeling also revealed genotype specific differences. These findings provide novel insights into mechanisms behind the differences in susceptibility of Cyp1a1-/- and Cyp1a2-/- mice to HLI and suggest novel pathways that need to be investigated as possible therapeutic targets for acute lung injury.