Increased expression and function of glutamate transporters in multiple sclerosis.
Recent studies have shown that glutamate excitotoxicity may be a component in the etiology of multiple sclerosis (MS). Glutamate transporters determine the levels of extracellular glutamate and are essential to prevent excitotoxicity. We have analyzed here the expression of the glutamate transporters EAAT1, EAAT2 and EAAT3 in control and in MS optic nerve samples. We observed an overall increase in the level of the glutamate transporters EAAT1 and EAAT2 mRNA and protein. In turn, functional assays showed that glutamate uptake was also increased in MS samples. Furthermore, glutamate transporter increases were mimicked in rat optic nerves treated with excitotoxic levels of glutamate. Together, these results indicate that enhanced expression of glutamate transporters in MS constitutes a regulatory response of glial cells to toxic levels of glutamate in the CNS during inflammation and neurodegeneration.
Vallejo-Illarramendi
Ainara
A
Departamento de Neurociencias, Universidad del País Vasco, E-48940, Leioa, Vizcaya, Spain.
Domercq
María
M
Pérez-Cerdá
Fernando
F
Ravid
Rivka
R
Matute
Carlos
C
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001253:Astrocytes / Q000502:physiology; D027341:Excitatory Amino Acid Transporter 1 / Q000235:genetics* / Q000378:metabolism; D027342:Excitatory Amino Acid Transporter 2; D050580:Excitatory Amino Acid Transporter 3 / Q000235:genetics* / Q000378:metabolism; D005260:Female; D050491:Glutamate Plasma Membrane Transport Proteins / Q000235:genetics* / Q000378:metabolism; D018698:Glutamic Acid / Q000378:metabolism; D006801:Humans; D008297:Male; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000378:metabolism* / Q000503:physiopathology*; D009410:Nerve Degeneration / Q000378:metabolism / Q000503:physiopathology; D009498:Neurotoxins / Q000378:metabolism; D009836:Oligodendroglia / Q000502:physiology; D020411:Oligonucleotide Array Sequence Analysis; D009900:Optic Nerve / Q000378:metabolism / Q000503:physiopathology; D012333:RNA, Messenger / Q000032:analysis
D027341:Excitatory Amino Acid Transporter 1; D027342:Excitatory Amino Acid Transporter 2; D050580:Excitatory Amino Acid Transporter 3; D050491:Glutamate Plasma Membrane Transport Proteins; D009498:Neurotoxins; D012333:RNA, Messenger; C493400:SLC1A1 protein, human; C493397:SLC1A2 protein, human; C493394:SLC1A3 protein, human; D018698:Glutamic Acid