FIGURE 8.

Oxidatively truncated phospholipids are required for TNFα-induced cytotoxicity. A, transient transfection increases PAFAH2. Jurkat cells were transfected by electroporation with PAFAH2 under control of a CMV promoter or an empty construct for 48 h before control lysates were resolved, and PAFAH2 and β-actin were analyzed by Western blotting. B, PAFAH2 overexpression does not reduce cellular phospholipid hydroperoxide content. HpODE-PC was determined as in Fig. 4. n = 3. C, overexpression of PAFAH2 abolishes TNFα-stimulated Az-PC accumulation. Jurkat cells transiently overexpressing PAFAH2 or not were stimulated with TNFα as above before Az-PC was quantitated by mass spectrometry. n = 3; *, p < 0.05. D, transient expression of PAFAH2 prevents apoptosis. Viability of Jurkat cells expressing ectopic PAFAH2 or not was determined by LDH release as in Fig. 1. n = 3; *, p < 0.05. E, schematic representation of TNFα stimulation of phospholipid oxidation and fragmentation to species that damage mitochondria, allowing caspase activation that promotes cell death. Error bars, S.E.