Excitotoxicity mediated by Ca2+-permeable GluR4-containing AMPA receptors invol...

• Autor(es): Santos, A. E. ; Duarte, C. B. ; Iizuka, M. ; Barsoumian, E. L. ; Ham, J. ; Lopes, M. C. ; Carvalho, A. P. ; Carvalho, A. L.
• Data: 2006
• Identificador Persistente: http://hdl.handle.net/10316/12659
• Origem: Estudo Geral - Universidade de Coimbra
• Assunto(s): Excitotoxicity; Glutamate; Ca2+-permeable AMPA receptors; GluR4 subunit; Activator protein-1 (AP-1) transcription factor
• Tipo de Documento: Artigo
• Idioma: Inglês

Descrição

Cells preferentially expressing GluR4-containing alpha-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid (AMPA) receptors are particularly sensitive to excitotoxicity mediated through non-N-methyl-D-aspartate receptors. However, the excitotoxic signalling pathways associated with GluR4-containing AMPA receptors are not known. In this work, we investigated the downstream signals coupled to excitotoxicity mediated by Ca2+-permeable GluR4-containing AMPA receptors, using a HEK 293 cell line constitutively expressing the GluR4flip subunit of AMPA receptors (HEK-GluR4). Glutamate stimulation of GluR4-containing AMPA receptors decreased cell viability, in a calcium-dependent manner, when the receptor desensitisation was prevented with cyclothiazide. The excitotoxic stimulation mediated through GluR4-containing AMPA receptors increased activator protein-1 (AP-1) DNA-binding activity. Inhibition of the AP-1 activity by overexpression of a c-Jun dominant-negative form protected HEK-GluR4 cells against excitotoxic damage. Taken together, the results indicate that overactivation of Ca2+-permeable GluR4-containing AMPA receptors is coupled to a death pathway mediated, at least in part, by the AP-1 transcription factor