THE ROLE OF REACTIVE OXYGEN AND NITROGEN SPECIES IN AIRWAY EPITHELIALGENE-EXPRESSION

The body first encounters deleterious inhaled substances, such as alle rgens, industrial particles, pollutants, and infectious agents, at the airway epithelium. When this occurs, the epithelium and its resident inflammatory cells respond defensively by increasing production of cyt okines, mucus, and reactive oxygen and nitrogen species (ROS/RNS). As inflammation in the airway increases, additional infiltrating cells in crease the level of these products. Recent interest has focused on ROS /RNS as potential modulators of the expression of inflammation-associa ted genes important to the pathogenesis of various respiratory disease s. ROS/RNS appear to play a variety of roles that lead to changes in e xpression of genes such as interleukin-6 and intercellular adhesion mo lecule 1. By controlling this regulation, the reactive species can ser ve as exogenous stimuli, as intercellular signaling molecules, and as modulators of the redox state in epithelial cells. Unraveling the mole cular mechanisms affected by ROS/RNS acting in these capacities should aid in the understanding of how stimulated defense mechanisms within the airway can lead to disease.