Lipid structural specificity of OxPL-stimulated induction of UPR genes. HUVECs were stimulated with lipids in medium 199 containing 2% FCS. All data obtained by RT-qPCR are normalized to the levels of β2-microglobulin mRNA. (A) HUVECs were incubated with 130 μM OxPLs containing palmitic and arachidonic acid residues: phosphatidylcholine (PC), phosphatidylglycerol (PG), phosphatidic acid (PA), or phosphatidylserine (PS). Control cells were incubated with the medium containing no lipids. After 4 hours, the cells were scraped into Laemmli buffer and analyzed by Western blotting for ATF4. (B) HUVECs were treated with oxidized or unoxidized phospholipids for 6 hours and then processed for quantification of ATF3 mRNA by RT-qPCR. (C) HUVECs were incubated with individual OxPLs (130 μM each) for 6 hours. (D) HUVECs were incubated for 6 hours with increasing concentrations of OxPAPC or lysoPC. (E) HUVECs were treated with the indicated concentrations of oxidized arachidonic acid (OxAA). (Inset) Data obtained after treatment of HUVECs for 6 hours with 130 μM OxPAPC or oxidized (OxAA) and unoxidized (AA) arachidonic acid. Error bars represent SD.
