HIFs, hypoxia, and vascular development.

Cellular oxygen (O2) concentrations are tightly regulated to maintain ATP levels required for metabolic reactions in the human body. Responses to changes in O2 concentrations are primarily regulated by the transcription factor hypoxia inducible factor (HIF). HIF activates transcription of genes that increase systemic O2 delivery or provide cellular metabolic adaptation under conditions of hypoxia. HIF activity is essential for embryogenesis and various processes in postnatal life, and therefore, HIF levels need to be precisely controlled. Abnormal HIF expression is related to numerous diseases of the vascular system, including heart disease, cancer, and chronic obstructive pulmonary disease.