Transportable and non-transportable inhibitors of L-glutamate uptake produce astrocytic stellation and increase EAAT2 cell surface expression

Neurochem Res. 2010 May;35(5):735-42. doi: 10.1007/s11064-010-0130-6. Epub 2010 Feb 9.

Abstract

Astrocytic excitatory amino acid transporters (EAATs) regulate excitatory transmission and limit excitotoxicity. Evidence for a functional interface between EAATs and glial fibrillary acidic protein (GFAP) relevant to astrocytic morphology led to investigations of actions of transportable (D-Aspartate (D-Asp) and (2S,3S,4R)-2-(carboxycyclopropyl)glycine (L-CCG-III)) and non-transportable (DL-threo-beta-benzyloxyaspartate (DL-TBOA)) inhibitors of Glu uptake in murine astrocytes. D-Asp (1 mM), L-CCG-III (0.5 mM) and DL-TBOA (0.5 mM) produced time-dependent (24-72 h) reductions in (3)[H]D-Asp uptake (approximately 30-70%) with little or no gliotoxicity. All drugs induced a profound change in phenotype from cobblestone to stellate morphology and image analysis revealed increases in the intensity of GFAP immunolabelling for L-CCG-III and DL-TBOA. Cytochemistry indicated localized changes in F-actin distribution. Cell surface expression of EAAT2, but not EAAT1, was elevated at 72 h. Blockade of Glu uptake by both types of EAAT inhibitor exerts longer-term effects on astrocytic morphology and a compensatory homeostatic rise in EAAT2 abundance.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acids, Dicarboxylic / metabolism
  • Amino Acids, Dicarboxylic / pharmacology
  • Animals
  • Aspartic Acid / metabolism
  • Aspartic Acid / pharmacology
  • Astrocytes / cytology
  • Astrocytes / drug effects*
  • Cells, Cultured
  • Excitatory Amino Acid Antagonists
  • Excitatory Amino Acid Transporter 1 / biosynthesis
  • Excitatory Amino Acid Transporter 2 / biosynthesis
  • Excitatory Amino Acid Transporter 2 / genetics*
  • Glutamates / metabolism*
  • Mice

Substances

  • Amino Acids, Dicarboxylic
  • Excitatory Amino Acid Antagonists
  • Excitatory Amino Acid Transporter 1
  • Excitatory Amino Acid Transporter 2
  • Glutamates
  • Slc1a2 protein, mouse
  • Slc1a3 protein, mouse
  • benzyloxyaspartate
  • (alpha-carboxycyclopropyl)glycine
  • Aspartic Acid