Polyunsaturated phospholipids and membrane-localized lipid radicals (PUFA-PL/Lipid ROS)

Polyunsaturated phospholipids (PUFA-PLs) and their oxidized derivatives, known as lipid radicals or lipid reactive oxygen species (ROS), are the central executioners of ferroptosis, a form of regulated, iron-dependent cell death (Dixon et al., 2012, Cell). These molecules are primarily located within biological membranes, where the bis-allylic hydrogens of polyunsaturated fatty acids are highly susceptible to abstraction by radicals, initiating a self-propagating chain reaction of lipid peroxidation (Stockwell et al., 2017, Cell). This process is enzymatically regulated by ACSL4 and LPCAT3, which incorporate PUFAs into phospholipids, and is normally suppressed by Glutathione Peroxidase 4 (GPX4), which reduces lipid hydroperoxides to stable alcohols (Doll et al., 2017, Nature Chemical Biology; Yang et al., 2014, Cell). In pathological contexts, the uncontrolled accumulation of these lipid radicals leads to catastrophic membrane damage and cell lysis, contributing to neurodegenerative diseases like Alzheimer's and Parkinson's, as well as ischemia-reperfusion injuries (Friedmann Angeli et al., 2014, Nature Cell Biology). Conversely, in oncology, inducing the accumulation of lipid ROS is a promising strategy to eliminate therapy-resistant cancer cells that have acquired a dependency on GPX4 for survival (Viswanathan et al., 2017, Nature). Therapeutic interventions include radical-trapping antioxidants (RTAs) like Ferrostatin-1 that quench lipid peroxy radicals and iron chelators that prevent the catalytic generation of these species, thereby protecting cells from ferroptotic damage.

Other names

Polyunsaturated fatty acid-containing phospholipidsLipid peroxidesLipid reactive oxygen speciesMembrane lipid hydroperoxidesLipid radicalsPUFA-PLs

Drugs targeting this system typically act as radical-trapping antioxidants (RTAs) to scavenge lipid peroxy radicals, iron chelators to prevent Fenton-mediated radical generation, or modulators of the GPX4 pathway to enhance the enzymatic reduction of lipid hydroperoxides to non-toxic lipid alcohols.