The glial glutamate transporter 1 (GLT1) is expressed by pancreatic beta-cells and prevents glutamate-induced beta-cell death.
J Biol Chem
; 286(16): 14007-18, 2011 Apr 22.
Article
en En
| MEDLINE
| ID: mdl-21335552
ABSTRACT
Glutamate is the major excitatory neurotransmitter of the central nervous system (CNS) and may induce cytotoxicity through persistent activation of glutamate receptors and oxidative stress. Its extracellular concentration is maintained at physiological concentrations by high affinity glutamate transporters of the solute carrier 1 family (SLC1). Glutamate is also present in islet of Langerhans where it is secreted by the α-cells and acts as a signaling molecule to modulate hormone secretion. Whether glutamate plays a role in islet cell viability is presently unknown. We demonstrate that chronic exposure to glutamate exerts a cytotoxic effect in clonal ß-cell lines and human islet ß-cells but not in α-cells. In human islets, glutamate-induced ß-cell cytotoxicity was associated with increased oxidative stress and led to apoptosis and autophagy. We also provide evidence that the key regulator of extracellular islet glutamate concentration is the glial glutamate transporter 1 (GLT1). GLT1 localizes to the plasma membrane of ß-cells, modulates hormone secretion, and prevents glutamate-induced cytotoxicity as shown by the fact that its down-regulation induced ß-cell death, whereas GLT1 up-regulation promoted ß-cell survival. In conclusion, the present study identifies GLT1 as a new player in glutamate homeostasis and signaling in the islet of Langerhans and demonstrates that ß-cells critically depend on its activity to control extracellular glutamate levels and cellular integrity.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Regulación de la Expresión Génica
/
Transportador 2 de Aminoácidos Excitadores
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Células Secretoras de Insulina
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Proteínas de Transporte de Glutamato en la Membrana Plasmática
Límite:
Animals
/
Humans
Idioma:
En
Revista:
J Biol Chem
Año:
2011
Tipo del documento:
Article
País de afiliación:
Italia