Erythropoietin (EPO) pathway (EPO pathway)

The Erythropoietin (EPO) pathway is the primary physiological system responsible for maintaining red blood cell mass and oxygen-carrying capacity in the blood [1]. This pathway is regulated by the Hypoxia-Inducible Factor (HIF) system, where HIF-2 alpha proteins bind to the hypoxia response element in the EPO promoter to drive gene expression in the kidneys and liver during low oxygen states [2]. Under normoxic conditions, HIF-prolyl hydroxylase (HIF-PH) enzymes hydroxylate HIF subunits, leading to their degradation by the von Hippel-Lindau (VHL) complex [3]. Pharmacological modulation of this pathway is a cornerstone in treating anemia, particularly in chronic kidney disease (CKD), where endogenous EPO production is impaired [4]. Therapeutic strategies include Erythropoiesis-Stimulating Agents (ESAs) that act as agonists for the Erythropoietin Receptor (EPOR) and newer HIF-PH inhibitors that stabilize HIF to activate the endogenous EPO promoter [5]. While effective at raising hemoglobin levels, over-activation of the pathway is associated with risks of hypertension and thromboembolic events [2, 5].

Other names

EPO promoterHIF-EPO axisHypoxia-inducible factor pathwayErythropoiesis-stimulating pathwayEPO-EPOR signaling

HIF-prolyl hydroxylase inhibition to stabilize HIF and activate the EPO promoter; Erythropoietin receptor agonism to stimulate erythroid progenitor cells.