Cell membrane phospholipids and lipid radicals

Cell membrane phospholipids, particularly those containing polyunsaturated fatty acids (PUFAs), are essential for maintaining the structural integrity and fluidity of cellular and organelle membranes (Stockwell et al., 2017, Cell). These lipids are highly susceptible to oxidative attack by reactive oxygen species or iron-dependent enzymes like lipoxygenases, leading to the formation of lipid hydroperoxides and highly reactive lipid radicals (Conrad & Pratt, 2019, Nature Chemical Biology). Lipid peroxyl and alkoxyl radicals are key intermediates in a self-amplifying chain reaction known as lipid peroxidation, which causes catastrophic damage to the lipid bilayer. This biochemical process is the defining feature of ferroptosis, a non-apoptotic form of regulated cell death implicated in neurodegeneration, stroke, and myocardial infarction (Dixon et al., 2012, Cell). Therapeutic intervention often involves the use of radical-trapping antioxidants (RTAs) that specifically neutralize these lipid radicals to terminate the peroxidation chain. Drugs such as ferrostatin-1 and liproxstatin-1 have been developed to target this pathway, showing promise in protecting against ischemia-reperfusion injury and organ damage. Conversely, in oncology, inducing the formation of these radicals is being explored as a method to trigger ferroptosis in therapy-resistant cancer cells. Understanding the dynamics of lipid radicals is therefore crucial for developing treatments that either preserve or destroy cell membranes depending on the clinical context.

Other names

Membrane lipidsPolyunsaturated fatty acidsPUFAsLipid peroxyl radicalsLipid hydroperoxidesLipid alkoxyl radicalsOxidized phospholipids

Radical trapping antioxidants (RTAs) act by scavenging lipid peroxyl radicals to terminate the self-propagating chain reaction of lipid peroxidation, thereby preventing the catastrophic loss of membrane integrity and subsequent ferroptotic cell death (Zilka et al., 2017, ACS Central Science).