title: Methionine sulfoximine, an inhibitor of glutamine synthetase, lowers brain glutamine and glutamate in a mouse model of ALS.
abstract: In an effort to alter the levels of neurochemicals involved in excitotoxicity, we treated mice with methionine sulfoximine (MSO), an inhibitor of glutamine synthetase. Since glutamate toxicity has been proposed as a mechanism for the degeneration of motor neurons in a variety of neurodegenerative diseases, we tested the effects of MSO on the transgenic mouse that overexpresses the mutant human SOD1(G93A) gene, an animal model for the primary inherited form of the human neurodegenerative disease amyotrophic lateral sclerosis (ALS). This treatment in vivo reduced glutamine synthetase activity measured in vitro by 85%. Proton magnetic resonance spectroscopy, with magic angle spinning of intact samples of brain tissue, showed that MSO treatment reduced brain levels of glutamine by 60% and of glutamate by 30% in both the motor cortex and the anterior striatum, while also affecting levels of GABA and glutathione. Kaplan-Meyer survival analysis revealed that MSO treatment significantly extended the lifespan of these mice by 8% (p<0.01). These results show that in the SOD1(G93A) model of neurodegenerative diseases, the concentration of brain glutamate (determined with (1)H-MRS) can be lowered by inhibiting in vivo the synthesis of glutamine with non-toxic doses of MSO.
authors.affiliation: Department of Psychiatry & Behavioral Neurosciences, Wayne State University School of Medicine, Detroit, MI 48201, USA.
authors.forename: Farhad
authors.initials: F
authors.lastname: Ghoddoussi
authors.forename: Matthew P
authors.initials: MP
authors.lastname: Galloway
authors.forename: Amruta
authors.initials: A
authors.lastname: Jambekar
authors.forename: Monica
authors.initials: M
authors.lastname: Bame
authors.forename: Richard
authors.initials: R
authors.lastname: Needleman
authors.forename: William S A
authors.initials: WS
authors.lastname: Brusilow
mesh_terms: D000690:Amyotrophic Lateral Sclerosis / Q000188:drug therapy* / Q000378:metabolism* / Q000503:physiopathology; D000818:Animals; D015415:Biomarkers / Q000032:analysis / Q000097:blood; D003342:Corpus Striatum / Q000187:drug effects / Q000378:metabolism; D004195:Disease Models, Animal; D015536:Down-Regulation / Q000187:drug effects / Q000502:physiology; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology* / Q000627:therapeutic use; D005974:Glutamate-Ammonia Ligase / Q000037:antagonists & inhibitors / Q000378:metabolism; D018698:Glutamic Acid / Q000378:metabolism; D005973:Glutamine / Q000037:antagonists & inhibitors / Q000378:metabolism; D005978:Glutathione / Q000378:metabolism; D006801:Humans; D053208:Kaplan-Meier Estimate; D009682:Magnetic Resonance Spectroscopy; D008717:Methionine Sulfoximine / Q000494:pharmacology* / Q000627:therapeutic use; D051379:Mice; D008822:Mice, Transgenic; D009044:Motor Cortex / Q000187:drug effects / Q000378:metabolism; D018696:Neuroprotective Agents / Q000494:pharmacology / Q000627:therapeutic use; D009498:Neurotoxins / Q000037:antagonists & inhibitors / Q000378:metabolism; D018384:Oxidative Stress / Q000187:drug effects / Q000502:physiology; D013482:Superoxide Dismutase / Q000235:genetics; D000072105:Superoxide Dismutase-1; D016896:Treatment Outcome; D005680:gamma-Aminobutyric Acid / Q000378:metabolism
chemical_list: D015415:Biomarkers; D018691:Excitatory Amino Acid Antagonists; D018696:Neuroprotective Agents; D009498:Neurotoxins; C000606290:SOD1 protein, human; D005973:Glutamine; D008717:Methionine Sulfoximine; D018698:Glutamic Acid; D005680:gamma-Aminobutyric Acid; C000606291:Sod1 protein, mouse; D013482:Superoxide Dismutase; D000072105:Superoxide Dismutase-1; D005974:Glutamate-Ammonia Ligase; D005978:Glutathione