Synergistic depletion of astrocytic glutathione by glucose deprivation and peroxynitrite : Correlation with mitochondrial dysfunction and subsequent cell death

• Published in: Journal of neurochemistry 2000-05, Vol.74 (5), p.1989-1998
• Main Authors: JU, C, YOON, K.-N, OH, Y.-K, KIM, H.-C, SHIN, C. Y, JAE RYUN RYU, KWANG HO KO, KIM, W.-K
• Format: Article
• Language: English
• Subjects: 3-morpholinosydnonimine; Animals; Astrocytes - metabolism; Astrocytes - physiology; Biological and medical sciences; Cell Survival - drug effects; Drug Synergism; Fundamental and applied biological sciences. Psychology; Glucose - deficiency; Glutathione - analogs & derivatives; Glutathione - deficiency; Glutathione - pharmacology; Isolated neuron and nerve. Neuroglia; Membrane Potentials - drug effects; Mitochondria - physiology; Molsidomine - analogs & derivatives; Molsidomine - pharmacology; Nitrates - pharmacology; Nitric Oxide Donors - pharmacology; Nitroso Compounds - pharmacology; Penicillamine - analogs & derivatives; Penicillamine - pharmacology; Rats; Rats, Sprague-Dawley; S-Nitroso-N-Acetylpenicillamine; S-Nitrosoglutathione; Vertebrates: nervous system and sense organs
• ISSN: 0022-3042; 1471-4159
• DOI: 10.1046/j.1471-4159.2000.0741989.x

Previously we reported that immunostimulated astrocytes were highly vulnerable to glucose deprivation. The augmented death was mimicked by the peroxynitrite (ONOO )-producing reagent 3-morpholinosydnonimine (SIN-1). Here we show that glucose deprivation and ONOO- synergistically deplete intracellular reduced glutathione (GSH) and augment the death of astrocytes via formation of cyclosporin A-sensitive mitochondrial permeability transition (MPT) pore. Astrocytic GSH levels were only slightly decreased by glucose deprivation or SIN-1 (200 microM) alone. In contrast, a rapid and large depletion of GSH was observed in glucose-deprived/ SIN-1-treated astrocytes. The depletion of GSH occurred before a significant release of lactate dehydrogenase (a marker of cell death). Superoxide dismutase and ONOO-scavengers completely blocked the augmented death, indicating that the reaction of nitric oxide with superoxide to form ONOO was implicated. Furthermore, nitrotyrosine immunoreactivity (a marker of ONOO-) was markedly enhanced in glucose-deprived/SIN-1 -treated astrocytes. Mitochondrial transmembrane potential (MTP) was synergistically decreased in glucose-deprived/SIN-1-treated astrocytes. The glutathione synthase inhibitor L-buthionine-(S,R)-sulfoximine markedly decreased the MTP and increased lactate dehydrogenase (LDH) releases in SIN-1-treated astrocytes. Cyclosporin A, an MPT pore blocker, completely prevented the MTP depolarization as well as the enhanced LDH releases in glucose-deprived/SIN-1-treated astrocytes.