(647d) Analysis of Lipid Peroxidation As a Function of Membrane Curvature and Lipid Composition

An imbalance of reactive oxygen species and antioxidants leads to oxidative stress, which causes lipid peroxidation within the cellular membrane. For example, ferroptosis is iron-dependent cell death characterized by the accumulation of lipid oxidation products. Diverse lipid composition and morphology of cellular membranes complicate the understanding of lipid peroxidation kinetics. Therefore, we analyzed how lipid chemistry and physical properties of the membrane, such as packing and curvature, impact lipid peroxidation. Herein, we prepared reconstituted lipid models that included a lipid peroxidation sensor, C11-BODIPY, and were exposed to hydroxyl radicals generated by Fenton’s reagent to induce lipid peroxidation. The oxidation rate and the extent were measured using fluorescence spectroscopy and microscopy. We adopted a tethered vesicle assay to analyze lipid peroxidation as a function of membrane curvature. Furthermore, membrane properties such as packing, fluidity, and diffusivity were measured using various probes and through fluorescence recovery after photobleaching. Our results confirmed that the rate limiting step of lipid peroxidation is the propagation step and showed greater lipid oxidation occurring with increasing curvature. While membrane curvature affects the packing defects of lipid membranes, the physical properties of the membrane tied with the curvature play a more critical role in lipid peroxidation.