RSV causes HIF-1α stabilization via NO release in primary bronchial epithelial cells

RSV infection is characterized by airway edema. Stabilization of hypoxia inducible factor-1α (HIF-1α) is important in both inflammation and edema formation. In this study we evaluated whether RSV induced release of nitric oxide (NO) by bronchial airway epithelial cells leading to the stabilization of HIF-1α and subsequent transcription of VEGF165. Primary human bronchial epithelial cells (HBEpC) were used; cell supernatants were analyzed. Western blot analysis was used for the detection of HIF-1α. Bronchial airway epithelial monolayer permeability was assessed using electric cell-substrate impedance sensing (ECIS) in real time. There was increased stabilization of HIF-1α in RSV infected cells. Addition of an NO inhibitor blocked RSV mediated HIF-1α expression. Antagonism of NO also inhibited VEGF production and HBEpC monolayer permeability. Our results demonstrate that in HBEpC, RSV induced NO causes stabilization of HIF-1α in vitro.