HIF-1α inhibition reduces nasal inflammation in a murine allergic rhinitis model.

BACKGROUND: Hypoxia-inducible factor 1α (HIF-1α) is an important regulator of immune and inflammatory responses. We hypothesized that nasal allergic inflammation is attenuated by HIF-1α inhibition and strengthened by HIF-1α stabilization. OBJECTIVE: To elucidate the role of HIF-1α in a murine model of allergic rhinitis (AR). METHODS: Mice were pretreated with the HIF-1α inhibitor 2-methoxyestradiol (2ME2) or the HIF-1α inducer cobalt chloride (CoCl(2)) in an established AR murine model using ovalbumin (OVA)-sensitized BALB/c mice. HIF-1α and vascular endothelial growth factor (VEGF) expression in nasal mucosa was measured and multiple parameters of allergic responses were evaluated. RESULTS: HIF-1α and VEGF levels were locally up-regulated in nasal mucosa during AR. Inflammatory responses to OVA challenge, including nasal symptoms, inflammatory cell infiltration, eosinophil recruitment, up-regulation of T-helper type 2 cytokines in nasal lavage fluid, and serum OVA-specific IgE levels were present in the OVA-challenged mice. 2ME2 effectively inhibited HIF-1α and VEGF expression and attenuated the inflammatory responses. Stabilization of HIF-1α by CoCl(2) facilitated nasal allergic inflammation. HIF-1α protein levels in nasal airways correlated with the severity of AR in mice. CONCLUSIONS: HIF-1α is intimately involved in the pathogenesis of nasal allergies, and the inhibition of HIF-1α may be useful as a novel therapeutic approach for AR.