Differential role of hypoxia-inducible factor 1 alpha in toll-like receptor-mediated and allergic inflammatory reactions.

Hypoxia-inducible factor 1 (HIF-1) is a transcription complex that plays a pivotal role in cellular adaptation to hypoxic conditions. The role of this factor in inflammatory reactions associated with infections and allergies has recently become evident. In this review we summarize our current knowledge concerning the accumulation and role of HIF-1 in Toll-like receptor-mediated and allergic inflammation. The differential molecular mechanisms used to stabilize this protein in various settings and its ability to support both proinflammatory and angiogenic responses suggest important functional roles in both innate immune responses and allergies. Importantly, the HIF-1 transcription complex is activated in human basophils during IgE-mediated inflammatory responses. It is involved in VEGF expression and subsequent promotion of angiogenesis and in controlling energy metabolism.