Nitric oxide synthase, inducible (NOS2) (iNOS)

Nitric oxide synthase, inducible (NOS2) is a calcium-independent enzyme that produces high levels of nitric oxide (NO) from L-arginine in response to inflammatory stimuli such as cytokines and bacterial lipopolysaccharides [1, 7]. Unlike its constitutive counterparts, NOS1 and NOS3, NOS2 expression is primarily controlled at the transcriptional and post-transcriptional levels, where the stability of the NOS2 messenger RNA (mRNA) transcript serves as a key regulatory checkpoint [6, 10, 15]. In chronic inflammatory conditions, sepsis, and various malignancies, the excessive production of NO leads to the generation of reactive nitrogen species like peroxynitrite, which mediate oxidative stress, DNA damage, and tissue injury [4, 14, 16]. Therapeutic strategies targeting this molecule include small-molecule inhibitors that block the enzyme's catalytic activity and experimental RNA-based therapies, such as antisense oligonucleotides and small interfering RNA (siRNA), designed to promote the degradation of the NOS2 mRNA transcript [7, 12, 17]. A significant clinical challenge remains the development of agents with sufficient selectivity for the inducible isoform to avoid inhibiting the essential physiological roles of endothelial and neuronal nitric oxide synthases [7, 16].

Other names

iNOSNOS2NOS-IIHepatocyte nitric oxide synthaseNOS2AInducible nitric oxide synthase mRNA

Competitive or non-competitive inhibition of the enzyme's catalytic site (e.g., heme or tetrahydrobiopterin binding sites), and post-transcriptional silencing via RNA interference (siRNA) or antisense-mediated mRNA degradation.