Nitrative stress in respiratory inflammation caused by influenza virus infection

Respiratory inflammation and hyperresponsiveness caused by various pathological stimulants and microbial infections are associated with excessive production of nitric oxide (NO) in airway epithelial and phagocytic cells. For example, in viral pneumonia caused by influenza and Sendai virus, NO contributes critically to inflammatory processes and pathological exacerbation in the airway. NO-mediated respiratory complications may be dependent on the complex reactions of NO, with simultaneously produced superoxide forming several reactive nitrogen species, most notably ONOO^-. These reactive nitrogen oxides can react with biologically important proteins, enzymes, lipids, and nucleic acids via oxidation, nitration, or nitrosylation reactions, producing nitrative stress. Recent studies indicate that nitrative stress is involved in inflammation by a number of mechanisms including modulation of host immune response, destruction of tissue architecture, activation or inactivation of enzymes and transcription factors, and so on. There is accumulating evidence for the involvement of NO and nitrative stress in respiratory diseases. In this review, we focus on the molecular mechanisms of NO-induced and nitrative stress-mediated respiratory inflammation and pathogenesis during respiratory viral infections.