Figure 1.
Biosynthesis of ether and ester glycerophospholipids and the chemical structures of the precursors used.
(A) Schematic overview of the biosynthesis of ether and ester glycerophospholipids. Note that 1-alkylglycerols such as HG (red box) may enter the pathway through phosphorylation to 1-alkylglycerol 3-phosphate by an alkylglycerol kinase. For abbreviations of the compounds and enzymes, see below. (B) The chemical structure of the compounds used in this study, HG and palmitin. DHAP; dihydroxyacetone phosphate, G3P; glycerol 3-phoshpate, DHAPAT; dihydroxyacetone phosphate acyltransferase, GPAT; glycerol phosphate acyltransferase, ADHAPS; alkyldihydroxyacetone phosphate synthase, LPA; lysophosphatidic acid, LPAAT; lysophosphatidic acid acyltransferase, PAP; phosphatidic acid phosphatase, EPT; ethanolamine phosphotransferase, CEPT; choline/ethanolamine phosphotransferase.
Figure 2.
Overall changes in the lipidome of HEp-2 cells after treatment with HG or palmitin.
HEp-2 cells were treated for 24 hours with HG (20 µM), palmitin (20 µM) or ethanol (0.1%, as control) before analyzing the lipidome by MS. (A) The total amount of the different lipid classes are shown as absolute values (note the logarithmic scale) and (B) the difference between treated cells and control cells are expressed as relative values.
Figure 3.
Quantitative analysis of glycerophospholipids after HG or palmitin treatment.
The major species of (A) PC O, (B) PC P, (C) PE O, (D) PE P, (E) PC and (F) PE, in HEp-2 cells treated with HG (20 µM), palmitin (20 µM) or ethanol (0.1%, as control) for 24 hours. The species shown here are species comprising more than 1% of the total mass of the ether lipids and more than 2% of PC and PE for at least one of the samples.
Figure 4.
Quantitative analysis of ceramide and glycosphingolipids after HG or palmitin treatment.
The major species of (A) Cer, (B) GlcCer, (C) LacCer, and (D) Gb3 in HEp-2 cells treated with HG (20 µM), palmitin (20 µM) or ethanol (0.1%, as control) for 24 hours. The species shown here are species comprising more than 1% of the total mass of any of the classes.
Figure 5.
Quantitative analysis of phosphoinositide lipids and LPC after HG or palmitin treatment.
The major species of (A) PI, (B) LPI, and (C) LPC in HEp-2 cells treated with HG (20 µM), palmitin (20 µM) or ethanol (0.1%, as control) for 24 hours. The species shown here are species comprising more than 2% of the total mass of the lipid class for at least one of the samples.
Figure 6.
Quantitative lipid analysis of PS, PG, PA, DAG, CE and SM.
The major species of (A) PS, (B) PG, (C) PA, (D) DAG, (E) CE, and (F) SM in HEp-2 cells treated with HG (20 µM), palmitin (20 µM) or ethanol (0.1%, as control) for 24 hours. The SM species labeled d18:1/23:0 and d18:1/23:1 may alternatively be d18:1//22:0(OH) and d18:1/22:1(OH). The species shown here are species comprising more than 2% of the total mass of the lipid class for at least one of the samples.