HIF-1α regulates factors involved in developmental and pathological angiogenesis. The steps of angiogenesis involve multiple gene products expressed by different cell types (e.g. endothelial cells and pericytes. A coordinated sequence of events is necessary with a tight balance of activators and inhibitors of angiogenesis. HIF-1α directly regulates genes involved in steps such as vasodilation, increased vascular permeability, extracellular matrix remodeling and proliferation. VEGF alone leads to hypervascularity with hyperpermeability whereas the vessels induced by HIF-1α are not leaky.
