Peroxynitrite-driven toxicity pathway

The **peroxynitrite-driven toxicity pathway** is not a single molecular target but rather a pathological process involving the formation and action of the reactive nitrogen species *peroxynitrite* (ONOO⁻). Peroxynitrite is generated in vivo by the rapid reaction between nitric oxide (NO) and superoxide anion (O₂•−), both produced during inflammation or cellular stress. It is a potent oxidant capable of damaging proteins, lipids, and DNA through direct oxidation or nitration reactions. This leads to disruption of enzyme activities, mitochondrial dysfunction, membrane channel inhibition, lipid peroxidation, DNA strand breaks with activation of poly(ADP-ribose) polymerase (PARP), energetic collapse in cells, apoptosis or necrosis[3][5]. \n\nPeroxynitrite-mediated cytotoxicity has been implicated in various diseases including neurodegeneration (e.g., white matter injury via microglial activation), cardiovascular disorders such as circulatory shock where it contributes to vascular failure and barrier dysfunctions[1][3], drug-induced toxicities from agents like doxorubicin and paraquat that increase its production[5], as well as general inflammatory conditions.\n\nTherapeutic strategies have focused on neutralizing peroxynitrite using decomposition catalysts like FeTMPyP or MnTMPyP—these have shown protective effects in preclinical models—or reducing its precursors via NOS inhibitors or SOD mimetics. However, because NO itself has essential physiological roles—including vasodilation and immune regulation—broad suppression can lead to adverse effects; thus selective targeting remains challenging[8].\n\n**Note:** "Peroxynitrite-driven toxicity pathway" refers to a mechanism/pathway rather than a discrete molecular entity such as an enzyme or receptor. Therefore it should not be considered a canonical therapeutic target but rather describes the downstream consequences of excessive reactive nitrogen species generation. For structured data purposes this entry would be flagged for review due to being mechanistic/pathway-based instead of representing an individual molecule/protein/receptor suitable for direct pharmacological targeting.

Other names

Peroxynitrite toxicityPeroxynitrite-mediated cytotoxicityONOO⁻-driven cell deathPeroxynitrite pathway

Scavenging or decomposing peroxynitrite to prevent oxidative damage\n- Inhibiting precursor radical formation (NO synthase inhibitors; SOD mimetics)\n- Enhancing endogenous antioxidant defenses