Fig. 7: Oleic and palmitic acid supplementation in HepG2 increases PG-PUFA2 leading to ferroptosis susceptibility.

To study the effect of lipid accumulation on ferroptosis sensitivity, HepG2 cells were exposed to glucose, insulin, three cytokines and different species of fatty acids, i.e., oleic and palmitic acid (OA/PA), arachidonic acid (AA 20:4, ω-6 PUFA) or docosahexaenoic acid (DHA 22:6, ω-3 PUFA). A Experimental design of fatty acid incubation and ferroptosis induction with GPX4 inhibitor ML162. B Neutral lipids measured with AdipoRed. C Percentage of cell death (with SytoxGreen) at increasing ML162 concentrations. After fitting non-linear regressions per condition, best-fit half maximal effective concentration (EC50) values were compared using Aikake Information Coefficient and one-way ANOVA with post-hoc testing. D Representative images of C11-BODIPY (581/591) dye in HepG2. Oxidized dye (green) indicates lipid radical oxygen species 2 h after ML162, as opposed to the normal reduced form (red). E Gene set enrichment analysis (GSEA) plots for gene sets “ferroptosis defenses” and “GSH” in HepG2 treated with OA/PA compared to solvent control (Control), with normalized enrichment score (NES) (n = 6). F Percentage of phosphatidylglycerol (PG) esterified with one or two polyunsaturated fatty acids, i.e., PG-PUFA and PG-PUFA2. Percentage of phosphatidylcholine and phosphatidylethanolamine with two PUFA, i.e., PC-PUFA2 and PE-PUFA2, respectively (n = 3). Data pooled from three independent experiments, performed in triplicate, except for C11-BODIPY (581/591). *p < 0.05; **p < 0.01; ***p < 0.001. One-way ANOVA with post-hoc test.