Brain-derived neurotrophic factor (BDNF) enhances GABA transport by modulating the trafficking of GABA transporter-1 (GAT-1) from the plasma membrane of rat cortical astrocytes

Research output: Contribution to journalJournal articleResearchpeer-review

  • Sandra H Vaz
  • Trine Nygaard Jørgensen
  • Sofia Cristóvão-Ferreira
  • Sylvie Duflot
  • Joaquim A Ribeiro
  • Gether, Ulrik
  • Ana M Sebastião
The ¿-aminobutyric acid (GABA) transporters (GATs) are located in the plasma membrane of neurons and astrocytes and are responsible for termination of GABAergic transmission. It has previously been shown that brain derived neurotrophic factor (BDNF) modulates GAT-1-mediated GABA transport in nerve terminals and neuronal cultures. We now report that BDNF enhances GAT-1-mediated GABA transport in cultured astrocytes, an effect mostly due to an increase in the V(max) kinetic constant. This action involves the truncated form of the TrkB receptor (TrkB-t) coupled to a non-classic PLC-¿/PKC-d and ERK/MAPK pathway and requires active adenosine A(2A) receptors. Transport through GAT-3 is not affected by BDNF. To elucidate if BDNF affects trafficking of GAT-1 in astrocytes, we generated and infected astrocytes with a functional mutant of the rat GAT-1 (rGAT-1) in which the hemagglutinin (HA) epitope was incorporated into the second extracellular loop. An increase in plasma membrane of HA-rGAT-1 as well as of rGAT-1 was observed when both HA-GAT-1-transduced astrocytes and rGAT-1-overexpressing astrocytes were treated with BDNF. The effect of BDNF results from inhibition of dynamin/clathrin-dependent constitutive internalization of GAT-1 rather than from facilitation of the monensin-sensitive recycling of GAT-1 molecules back to the plasma membrane. We therefore conclude that BDNF enhances the time span of GAT-1 molecules at the plasma membrane of astrocytes. BDNF may thus play an active role in the clearance of GABA from synaptic and extrasynaptic sites and in this way influence neuronal excitability.
Original languageEnglish
JournalJournal of Biological Chemistry
Volume286
Issue number47
Pages (from-to)40464-76
Number of pages13
ISSN0021-9258
DOIs
Publication statusPublished - 2011

    Research areas

  • Adenosine, Animals, Astrocytes, Brain-Derived Neurotrophic Factor, Cell Membrane, Cerebral Cortex, Extracellular Space, GABA Plasma Membrane Transport Proteins, Gene Expression Regulation, HEK293 Cells, Humans, Protein Isoforms, Protein Transport, Rats, Receptor, trkB, gamma-Aminobutyric Acid

ID: 38503172