Inducible nitric oxide synthase and Cyclooxygenase-2 (iNOS/COX-2)

Inducible nitric oxide synthase (iNOS) and Cyclooxygenase-2 (COX-2) are key pro-inflammatory enzymes that are typically co-expressed in response to inflammatory stimuli such as cytokines and bacterial lipopolysaccharides (Nathan, 1997, J Clin Invest). iNOS is responsible for the high-output production of nitric oxide, a potent signaling molecule and free radical, while COX-2 catalyzes the rate-limiting step in the synthesis of prostaglandins, particularly PGE2, which mediates pain and fever (Vane et al., 1998, Annu Rev Pharmacol Toxicol). The simultaneous induction of these two enzymes is a hallmark of the inflammatory response and is primarily regulated by the transcription factor NF-kappaB (Surh et al., 2001, Nat Rev Cancer). Overexpression of iNOS and COX-2 is linked to various chronic inflammatory conditions, including rheumatoid arthritis, inflammatory bowel disease, and certain types of cancer where they promote angiogenesis and cell survival (Coussens & Werb, 2002, Nature). Therapeutic strategies often focus on dual inhibition of their expression or activity to achieve synergistic anti-inflammatory effects while potentially reducing the side effects associated with high-dose monotherapy. However, selective inhibition of COX-2 has been associated with increased cardiovascular risks, necessitating careful drug design and patient monitoring (Bresalier et al., 2005, NEJM).

Other names

NOS2PTGS2Nitric oxide synthase 2Prostaglandin-endoperoxide synthase 2iNOS/COX-2 pathway

Drugs targeting this system act by either directly inhibiting the catalytic activity of the iNOS and COX-2 enzymes or by suppressing their gene expression through the inhibition of upstream signaling pathways, most notably the NF-kappaB and MAPK pathways (Gupta et al., 2010, Herb Med).