Glucocorticoid receptor interaction with TrkB promotes BDNF-triggered PLC-gamma signaling for glutamate release via a glutamate transporter.
Proc Natl Acad Sci U S A
; 106(2): 647-52, 2009 Jan 13.
Article
en En
| MEDLINE
| ID: mdl-19126684
ABSTRACT
An increase in glucocorticoid levels and down-regulation of BDNF (brain-derived neurotrophic factor) are supposed to be involved in the pathophysiology of depressive disorders. However, possible crosstalk between glucocorticoid- and BDNF-mediated neuronal functions in the CNS has not been elucidated. Here, we examined whether chronic glucocorticoid exposure influences BDNF-triggered intracellular signaling for glutamate release via a glutamate transporter. We found that chronic exposure to dexamethasone (DEX, a synthetic glucocorticoid) suppressed BDNF-induced glutamate release via weakening the activation of the PLC-gamma (phospholipase C-gamma)/Ca(2+) system in cultured cortical neurons. We demonstrated that the GR (glucocorticoid receptor) interacts with receptor tyrosine kinase for BDNF (TrkB). Following DEX treatment, TrkB-GR interaction was reduced due to the decline in GR expression. Corticosterone, a natural glucocorticoid, also reduced TrkB-GR interaction, BDNF-stimulated PLC-gamma, and BDNF-triggered glutamate release. Interestingly, BDNF-dependent binding of PLC-gamma to TrkB was diminished by DEX. SiRNA transfection to induce a decrease in endogenous GR mimicked the inhibitory action of DEX. Conversely, DEX-inhibited BDNF-activated PLC-gamma signaling for glutamate release was recovered by GR overexpression. We propose that TrkB-GR interaction plays a critical role in the BDNF-stimulated PLC-gamma pathway, which is required for glutamate release, and the decrease in TrkB-GR interaction caused by chronic exposure to glucocorticoids results in the suppression of BDNF-mediated neurotransmitter release via a glutamate transporter.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Receptores de Glucocorticoides
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Ácido Glutámico
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Factor Neurotrófico Derivado del Encéfalo
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Receptor trkB
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Sistema de Transporte de Aminoácidos X-AG
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Fosfolipasa C gamma
Límite:
Animals
Idioma:
En
Revista:
Proc Natl Acad Sci U S A
Año:
2009
Tipo del documento:
Article
País de afiliación:
Japón