title: Oxidized LDL triggers phosphatidylserine exposure in human monocyte cell lines by both caspase-dependent and -independent mechanisms.
abstract: Monocytic cell lines have been extensively used to characterize and model various features of the atherogenic process. We found striking differences in the apoptotic pathways of U937 cells and THP-1 cells exposed to copper-oxidized LDL. While phosphatidylserine exposure occurred in both lines, caspase activation was only apparent in the THP-1 cells. OxLDL caused caspase activity to decrease below that seen in untreated U937 cells, and this corresponded with a loss in intracellular thiols. In conclusion, exposure of U937 cells to oxLDL did not trigger a conventional apoptosis response, but still resulted in phosphatidylserine externalization.
authors.affiliation: Free Radical Biochemistry Laboratory, School of Biological Sciences, University of Canterbury, Private Bag 4800, Christchurch, New Zealand.
authors.forename: Sarah K
authors.initials: SK
authors.lastname: Baird
authors.forename: Mark B
authors.initials: MB
authors.lastname: Hampton
authors.forename: Steven P
authors.initials: SP
authors.lastname: Gieseg
mesh_terms: D017209:Apoptosis / Q000502:physiology; D020169:Caspases / Q000378:metabolism*; D002460:Cell Line; D048430:Cell Shape; D002470:Cell Survival; D004789:Enzyme Activation; D006801:Humans; D008077:Lipoproteins, LDL / Q000494:pharmacology*; D009000:Monocytes / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D010718:Phosphatidylserines / Q000378:metabolism*; D013438:Sulfhydryl Compounds / Q000378:metabolism
chemical_list: D008077:Lipoproteins, LDL; D010718:Phosphatidylserines; D013438:Sulfhydryl Compounds; C099252:oxidized low density lipoprotein; D020169:Caspases