Hypoxia-inducible factor signaling pathway (HIF signaling pathway)

The Hypoxia-inducible factor (HIF) signaling pathway is a critical cellular mechanism that senses and responds to low oxygen levels (hypoxia). It is primarily mediated by HIF transcription factors, which consist of an oxygen-sensitive alpha subunit (HIF-1α, HIF-2α, or HIF-3α) and a constitutively expressed beta subunit (HIF-1β). Under normoxic conditions, prolyl hydroxylase domain (PHD) enzymes hydroxylate the alpha subunit, leading to its recognition by the von Hippel-Lindau (VHL) protein and subsequent proteasomal degradation. In hypoxia, this degradation is inhibited, allowing HIF-alpha to translocate to the nucleus, dimerize with HIF-beta, and activate the transcription of genes involved in erythropoiesis, angiogenesis, and glucose metabolism. This pathway is a major therapeutic target; PHD inhibitors are used to treat anemia in chronic kidney disease by stimulating endogenous erythropoietin, while HIF inhibitors (specifically HIF-2α antagonists) are utilized in the treatment of certain cancers, such as renal cell carcinoma associated with VHL disease.

Other names

HIF pathwayHypoxia-inducible factor pathwayCellular response to hypoxia

Drugs targeting this pathway typically act as Prolyl Hydroxylase (PHD) inhibitors to stabilize HIF-alpha subunits for treating anemia, or as HIF-2 alpha inhibitors to prevent transcription of oncogenic genes in cancer.