TNFR1 mediates increased neuronal membrane EAAT3 expression after in vivo cerebral ischemic preconditioning.
A short ischemic event (ischemic preconditioning) can result in subsequent resistance to severe ischemic injury (ischemic tolerance). Glutamate is released after ischemia and produces cell death. It has been described that after ischemic preconditioning, the release of glutamate is reduced. We have shown that an in vitro model of ischemic preconditioning produces upregulation of glutamate transporters which mediates brain tolerance. We have now decided to investigate whether ischemic preconditioning-induced glutamate transporter upregulation takes also place in vivo, its cellular localization and the mechanisms by which this upregulation is controlled. A period of 10 min of temporary middle cerebral artery occlusion was used as a model of ischemic preconditioning in rat. EAAT1, EAAT2 and EAAT3 glutamate transporters were found in brain from control animals. Ischemic preconditioning produced an up-regulation of EAAT2 and EAAT3 but not of EAAT1 expression. Ischemic preconditioning-induced increase in EAAT3 expression was reduced by the TNF-alpha converting enzyme inhibitor BB1101. Intracerebral administration of either anti-TNF-alpha antibody or of a TNFR1 antisense oligodeoxynucleotide also inhibited ischemic preconditioning-induced EAAT3 up-regulation. Immunohistochemical studies suggest that, whereas the expression of EAAT3 is located in both neuronal cytoplasm and plasma membrane, ischemic preconditioning-induced up-regulation of EAAT3 is mainly localized at the plasma membrane level. In summary, these results demonstrate that in vivo ischemic preconditioning increases the expression of EAAT2 and EAAT3 glutamate transporters the upregulation of the latter being at least partly mediated by TNF-alpha converting enzyme/TNF-alpha/TNFR1 pathway.
Pradillo
J M
JM
Departamento de Farmacología, Facultad de Medicina, Universidad Complutense de Madrid, 28040 Madrid, Spain.
Hurtado
O
O
Romera
C
C
Cárdenas
A
A
Fernández-Tomé
P
P
Alonso-Escolano
D
D
Lorenzo
P
P
Moro
M A
MA
Lizasoain
I
I
D051722:ADAM Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism; D000072198:ADAM17 Protein; D000818:Animals; D000906:Antibodies / Q000494:pharmacology; D002545:Brain Ischemia / Q000378:metabolism* / Q000503:physiopathology; D002462:Cell Membrane / Q000378:metabolism; D002540:Cerebral Cortex / Q000098:blood supply / Q000378:metabolism* / Q000503:physiopathology; D004195:Disease Models, Animal; D004791:Enzyme Inhibitors / Q000494:pharmacology; D027342:Excitatory Amino Acid Transporter 2 / Q000378:metabolism; D050580:Excitatory Amino Acid Transporter 3 / Q000378:metabolism*; D018698:Glutamic Acid / Q000378:metabolism; D020244:Infarction, Middle Cerebral Artery / Q000378:metabolism / Q000503:physiopathology; D019194:Ischemic Preconditioning; D008297:Male; D009474:Neurons / Q000378:metabolism*; D020319:Oligodeoxyribonucleotides, Antisense / Q000494:pharmacology; D051381:Rats; D011916:Rats, Inbred F344; D018124:Receptors, Tumor Necrosis Factor / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D047888:Receptors, Tumor Necrosis Factor, Type I; D053319:Tumor Necrosis Factor Decoy Receptors; D014409:Tumor Necrosis Factor-alpha / Q000037:antagonists & inhibitors / Q000378:metabolism; D015854:Up-Regulation / Q000502:physiology
D000906:Antibodies; D004791:Enzyme Inhibitors; D027342:Excitatory Amino Acid Transporter 2; D050580:Excitatory Amino Acid Transporter 3; D020319:Oligodeoxyribonucleotides, Antisense; D018124:Receptors, Tumor Necrosis Factor; D047888:Receptors, Tumor Necrosis Factor, Type I; C493398:Slc1a1 protein, rat; C493395:Slc1a2 protein, rat; D053319:Tumor Necrosis Factor Decoy Receptors; D014409:Tumor Necrosis Factor-alpha; C069521:recombinant human tumor necrosis factor-binding protein-1; D018698:Glutamic Acid; D051722:ADAM Proteins; D000072198:ADAM17 Protein