Pivotal role of c-Fos in nitric oxide synthase 2 expression in airway epithelial cells.

The regulation of nitric oxide synthase 2 (NOS2) in airway epithelial cells plays a key role in the innate host response to a wide variety of microbial agents and also participates in the generation of pathologic airway inflammation. Among the important signalling cascades that direct NOS2 gene expression are nuclear factor kappaB (NFkappaB) and interferon-gamma (IFNgamma)/signal transducer and activator of transcription 1 (STAT-1). Previous studies suggest activator protein-1 (AP-1), in particular c-Fos component of AP-1, influences NOS2 expression.

Gene expression profile of human airway epithelium induced by hyperoxia in vivo.

Hyperoxia leads to oxidative modification and damage of macromolecules in the respiratory tract with loss of biological functions. Given the lack of antioxidant gene induction with acute exposure to 100% oxygen, we hypothesized that clearance pathways for oxidatively modified proteins may be induced and serve in the immediate cellular response to preserve the epithelial layer. To test this, airway epithelial cells were obtained from individuals under ambient oxygen conditions and after breathing 100% oxygen for 12 h.