Vitamin E Inhibits Anti-Fas-Induced Phosphatidylserine Oxidation but Does Not Affect Its Externalization During Apoptosis in Jurkat T Cells and Their Phagocytosis by J774A.1 Macrophages

Apoptosis and phagocytosis of apoptotic cells provide for effective and harmless clearance of unwanted or damaged cells in the body. Preferential oxidation of one particular class of phospholipids, phosphatidylserine (PS), is a typical trait of both oxidant- and nonoxidant-induced apoptosis. PS oxidation is likely to play an important role in phagocytosis either by affecting PS externalization acting as an "eat me" signal or by more effective recognition of apoptotic cells by macrophage receptors. This implies that antioxidants effective in inhibiting PS oxidation may affect PS externalization and/or effective removal of apoptotic cells. Therefore, it is essential to determine whether vitamin E, the major lipid-soluble antioxidant of membranes, inhibits PS oxidation, and hence blocks apoptosis/phagocytosis. To test this, we studied the effects of vitamin E on PS oxidation and signaling using a model of anti-Fas-triggered apoptosis in Jurkat T cells. We found that incubation of cells with vitamin E (0.25-5...