1. Increased glutamine synthetase but normal EAAT2 expression in platelets of ALS patients.
- Author
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Bos IW, Hoogland G, Meine Jansen CF, Willigen Gv, Spierenburg HA, van den Berg LH, and de Graan PN
- Subjects
- Adult, Amyotrophic Lateral Sclerosis blood, Amyotrophic Lateral Sclerosis enzymology, Blood Platelets enzymology, Blotting, Western, Case-Control Studies, Female, Humans, Male, Middle Aged, Amyotrophic Lateral Sclerosis metabolism, Blood Platelets metabolism, Excitatory Amino Acid Transporter 2 blood, Glutamate-Ammonia Ligase blood
- Abstract
Amyotrophic lateral sclerosis is a fatal neurodegenerative disease and glutamate excitotoxicity has been implicated in its pathogenesis. Platelets contain a glutamate uptake system and express components of the glutamate-glutamine cycle, such as the predominant glial excitatory amino acid transporter 2 (EAAT2). In several neurological diseases platelets have proven to be systemic markers for the disease. We compared properties of key components of the glutamate-glutamine cycle in blood platelets of ALS patients and healthy controls. Platelets were analyzed for (3)H-glutamate uptake in the presence or absence of thrombin and for EAAT2 and glutamine synthetase protein expression by Western blotting. Platelets of ALS patients showed a 37% increase in expression of glutamine synthetase, but normal expression of glutamate transporter EAAT2. Glutamate uptake in resting or thrombin-stimulated platelets did not differ significantly between platelets from ALS patients and controls. Thrombin-stimulation resulted in about a seven-fold increase in glutamate uptake. Our data suggest that glutamine synthetase may be a peripheral marker of ALS and encourage further investigation into the role of this enzyme in ALS. more...
- Published
- 2006
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