System x(c)- and thioredoxin reductase 1 cooperatively rescue glutathione deficiency

• Published in: The Journal of biological chemistry 2010-07, Vol.285 (29), p.22244
• Main Authors: Mandal, Pankaj Kumar, Seiler, Alexander, Perisic, Tamara, Kölle, Pirkko, Banjac Canak, Ana, Förster, Heidi, Weiss, Norbert, Kremmer, Elisabeth, Lieberman, Michael W, Bannai, Shiro, Kuhlencordt, Peter, Sato, Hideyo, Bornkamm, Georg W, Conrad, Marcus
• Format: Article
• Language: English
• Subjects: Amino Acid Transport System y+ - metabolism; Animals; Buthionine Sulfoximine - pharmacology; Cell Death - drug effects; Coculture Techniques; Cysteine - metabolism; Extracellular Space - drug effects; Extracellular Space - metabolism; Glutamate-Cysteine Ligase - deficiency; Glutamate-Cysteine Ligase - metabolism; Glutathione - deficiency; Glutathione - metabolism; Green Fluorescent Proteins - metabolism; Intracellular Space - drug effects; Intracellular Space - metabolism; Mice; Thioredoxin Reductase 1 - deficiency; Thioredoxin Reductase 1 - metabolism; Thioredoxin Reductase 2 - deficiency; Thioredoxin Reductase 2 - metabolism
• ISSN: 1083-351X
• DOI: 10.1074/jbc.M110.121327

GSH is the major antioxidant and detoxifier of xenobiotics in mammalian cells. A strong decrease of intracellular GSH has been frequently linked to pathological conditions like ischemia/reperfusion injury and degenerative diseases including diabetes, atherosclerosis, and neurodegeneration. Although GSH is essential for survival, the deleterious effects of GSH deficiency can often be compensated by thiol-containing antioxidants. Using three genetically defined cellular systems, we show here that forced expression of xCT, the substrate-specific subunit of the cystine/glutamate antiporter, in gamma-glutamylcysteine synthetase knock-out cells rescues GSH deficiency by increasing cellular cystine uptake, leading to augmented intracellular and surprisingly high extracellular cysteine levels. Moreover, we provide evidence that under GSH deprivation, the cytosolic thioredoxin/thioredoxin reductase system plays an essential role for the cells to deal with the excess amount of intracellular cystine. Our studies provide first evidence that GSH deficiency can be rescued by an intrinsic genetic mechanism to be considered when designing therapeutic rationales targeting specific redox enzymes to combat diseases linked to GSH deprivation.