Untargeted
lipidomics reveals GCH1 overexpression
cells protect from ferroptotic degradation of specific lipids. Heat
map (one-way ANOVA; FDR-corrected p-value <0.05)
showing changes in phospholipid profile (A), and glycerolipid, sphingolipid,
and free fatty acid profiles (B) of DMSO or 10 μM IKE treated GCH1-overexpressing (GCH1 OE) and parental
HT-1080 cells. Each row represents Z-scored-normalized
intensities of the differentiated lipid species. Each column represents
the mean of n = 2 technical replicates of n = 5 independent biological replicates. The relative abundance
of lipid is color-coded from red indicating high signal intensity
to dark blue indicating low intensity and clustered using Pearson
correlations. Abbreviations: PC, phosphatidylcholine; PE, phosphatidyl-ethanolamine;
PI, phosphatidylinositol; PG, phosphatidylglycerol; LPC, lysoPC; LPE,
LysoPE; PE P-, plasmalogen PE; PC/PE -O, ether-linked PE/PC; TAG,
triacylglycerol; DAG, diacylglycerol; FA, fatty acid; CE, cholesterylester;
CoQ10, coenzyme Q10; Cer, ceramide; HexCer,
monohexosyl-Cer. (C) Line structure of representative phospholipids
PC 18:0_20:4 with one saturated acyl chain and one polyunsaturated
fatty acyl (PUFA) chain, as well as PC 20:4_20:4 with two PUFA chains.
(D) Treatment of parental and GCH1 OE HT-1080 cells
with 4-nitrobenzoate in the absence of CoQ10 with ferroptosis
induction by 8 μM IKE. Viability is plotted as biological replicates
± SEM n = 3. (E) Treatment of parental and GCH1 OE HT-1080 cells with exogenous PC 20:4_20:4, 18:0_20:4,
18:0_22:6, and PG 22:6_22:6 (concentrations 0–50 μM).
Viability is plotted as mean ± SEM of n = 4
replicates.