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A Primary Regulatory Role For Glutathione Transport In FasL‐Induced Apoptosis In Jurkat Cells.
Author(s) -
Franco Rodrigo,
Cidlowski John A
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.5.a257-c
Subject(s) - glutathione , intracellular , apoptosis , jurkat cells , microbiology and biotechnology , fas ligand , reactive oxygen species , chemistry , programmed cell death , efflux , extracellular , biochemistry , biology , immunology , t cell , enzyme , immune system
Changes in the intracellular environment of the cells have been demonstrated to regulate the activation of proapoptotic enzymes and thus, the progression of programmed cell death. Intracellular glutathione GSHi depletion is an early hallmark observed in apoptosis. Recently, we have shown that GSH efflux occurs during Fas ligand (FasL)‐induced apoptosis and is mediated by a GSH/organic anion (OA‐) exchanger with characteristics of an SLCO/OATP‐like transporter. However, the mechanisms involved in the regulation of apoptosis by GSH transport have not been defined. We now seek to evaluate the relationship between GSH transport, GSH depletion, and both the generation of reactive oxygen species (ROS) and changes in ionic homeostasis associated with apoptotic volume decrease (AVD) during FasL‐induced apoptosis in Jurkat cells. We observed that intracellular GSH depletion was paralleled by the generation of different ROS including H2O2, O2−, OH− as well lipid peroxides. However, specific inhibition of these ROS by several antioxidants shown that GSH loss was independent from the generation of ROS. In contrast, GSH efflux was shown to be necessary for ROS generation. Additionally, inhibition of ROS generation by antioxidants did not prevent apoptosis. Conversely, the reduction in intracellular GSH content was observed to be paralleled by cell shrinkage or AVD. Specifically, GSH/OA‐‐mediated efflux of GSH was shown to modulate [K+]i loss and AVD. Prevention of [K+]i loss by high extracellular K+ medium, did not affect the GSH efflux, but it inhibited AVD and the progression of the execution phase of apoptosis. These results clearly uncouple for the first time the role of GSH loss in apoptosis from the formation of ROS, and suggest that the modulation of apoptosis by GSH transport is tightly coupled to K+ loss.