Heme oxygenase 1 (HO-1) (HO-1)

Heme oxygenase 1 (HO-1) is an inducible enzyme that serves as the rate-limiting step in the catabolism of heme into biliverdin, carbon monoxide (CO), and free iron [1]. It is a critical component of the cellular antioxidant defense system and is primarily regulated by the transcription factor Nrf2, which can be activated through upstream signaling pathways including PI3K, Akt, and mTORC1 [2, 3]. The products of HO-1 activity—biliverdin (subsequently converted to bilirubin) and CO—exert potent anti-inflammatory, anti-apoptotic, and antioxidant effects, providing cytoprotection against various forms of cellular stress [4]. While HO-1 induction is therapeutically beneficial in conditions like cardiovascular disease, organ transplantation, and neurodegeneration, its overexpression in many cancers promotes tumor growth, angiogenesis, and resistance to chemotherapy [5]. Pharmacological strategies include the use of Nrf2 activators like dimethyl fumarate to induce HO-1 for inflammatory diseases, or HO-1 inhibitors like metalloporphyrins to sensitize tumors to treatment [4, 5].

Other names

HMOX1HO1HSP32Heme oxygenase (decycling) 1

Induction of Heme oxygenase 1 expression through Nrf2 activation or direct enzymatic modulation to catalyze the breakdown of heme into biliverdin, carbon monoxide, and iron, which collectively exert antioxidant and anti-inflammatory effects [1, 2].