Modulating nuclear factor erythroid 2-related factor 2 and heme oxygenase-1 in liver-brain axis disorders

Figure 2 Enzymatic reaction and function of heme oxygenase-1. Heme oxygenase-1 (HO-1) is a multifaceted enzyme critical for cellular homeostasis, integrating antioxidant defense, immune regulation, vascular protection, and stress adaptation through its degradation products (bilirubin, carbon monoxide, and free iron). HO-1 Leads to the generation of biliverdin, release of carbon monoxide and ferrous iron (Fe²⁺). Biliverdin is transformed into bilirubin by the biliverdin reductase enzyme. Fe²⁺ can be bound by the iron storage protein ferritin. HO-1: Heme oxygenase-1; O₂: Oxygen; NADPH: Nicotinamide adenine dinucleotide phosphate; CO: Carbon monoxide; Fe²⁺: Ferrous iron.