ABSTRACT
Allergen-induced recruitment of T lymphocytes and eosinophils to the airways is associated with increased expression of the transcription factor GATA-3. In this study, the relationship between airway inflammation and GATA-3 expression in the lungs was investigated using ragweed-sensitized C57BL/6J mice. Intratracheal ragweed challenge increased both the number of GATA-3-expressing cells in the perivascular and peribronchial regions and the amount of expression per cell. Interleukin (IL)-4 and IL-5 levels in bronchoalveolar lavage fluid were upregulated in parallel with GATA-3 expression. GATA-3 mRNA and protein colocalized to eosinophils. Eosinophils isolated from the lungs and stimulated with phorbol 12-myristate 13-acetate and/or A-23187 released IL-5. The release was inhibited by actinomycin D, which indicates that de novo synthesis of the cytokine was involved. Western blot analysis of proteins from isolated eosinophils demonstrated expression of the p50 subunit of nuclear factor-kappaB, a transcription factor that is implicated in control of GATA-3 expression. These data provide evidence that allergen challenge increases GATA-3 and proinflammatory cytokine expression by pulmonary eosinophils, which could provide positive feedback for the inflammatory response.
Subject(s)
DNA-Binding Proteins/genetics , Eosinophils/immunology , Interleukin-4/analysis , Interleukin-5/analysis , Respiratory Hypersensitivity/immunology , Ribonucleases , Trans-Activators/genetics , Allergens/immunology , Animals , Asthma/immunology , Blood Proteins/analysis , Bronchoalveolar Lavage Fluid/chemistry , Bronchoalveolar Lavage Fluid/immunology , Chemotaxis, Leukocyte/immunology , DNA-Binding Proteins/analysis , Eosinophil Granule Proteins , Eosinophils/chemistry , Eosinophils/cytology , GATA3 Transcription Factor , Gene Expression/immunology , In Situ Hybridization , In Vitro Techniques , Interleukin-4/biosynthesis , Interleukin-5/biosynthesis , Male , Mice , Mice, Inbred C57BL , Plant Proteins/immunology , RNA, Messenger/analysis , Th2 Cells/immunology , Trans-Activators/analysis , Transcription, Genetic/immunologyABSTRACT
Excess nitric oxide (NO) generation in the presence of superoxide anion (O2-) leads to the formation of peroxynitrite which may result in lung injury. Oxidant-mediated lung injury has a critical role in pulmonary diseases. We therefore determined whether peroxynitrite causes lung fluid accumulation, lipid peroxidation, and formation of nitrotyrosine using an isolated perfused rat lung model. The lung weight gain during bolus peroxynitrite infusion increased in a dose-dependent manner over a range of 3 to 30 mumole. Concomitantly, bronchoalveolar lavage Ficoll also increased, indicative of increased endothelial permeability. Peroxynitrite increased the production of thiobarbituric acid reactive substances, an index of lipid peroxidation. Furthermore, nitrotyrosine levels in lung tissue rose with increased concentration of peroxynitrite, as determined by Western blot using antinitrotyrosine antibodies. These results suggest that peroxynitrite, formed from NO and O2-, leads to increased pulmonary fluid accumulation, possibly through lipid peroxidation and/or nitration of cell membrane proteins.
