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Transportable and Non-transportable Inhibitors of L-glutamate Uptake Produce Astrocytic Stellation and Increase EAAT2 Cell Surface Expression

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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-β-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.

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Acknowledgments

Supported by the NH&MRC Australia (#509319). CLL and PMB acknowledge receipt of Dora Lush Postgraduate Scholarship and Research Fellowship from the NH&MRC, respectively. Gifts of antibodies are gratefully acknowledged.

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Authors and Affiliations

  1. Molecular Neuropharmacology, Florey Neuroscience Institutes, Parkville, VIC, 3053, Australia

    Chew L. Lau, Philip M. Beart & Ross D. O’Shea

  2. Department of Pharmacology, Florey Neuroscience Institutes, University of Melbourne, Alan Gilbert Building NNF2, Grattan St, Parkville, VIC, 3010, Australia

    Philip M. Beart & Ross D. O’Shea

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  1. Chew L. Lau
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  2. Philip M. Beart
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  3. Ross D. O’Shea
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Correspondence to Philip M. Beart.

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Lau, C.L., Beart, P.M. & O’Shea, R.D. Transportable and Non-transportable Inhibitors of L-glutamate Uptake Produce Astrocytic Stellation and Increase EAAT2 Cell Surface Expression. Neurochem Res 35, 735–742 (2010). https://doi.org/10.1007/s11064-010-0130-6

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  • DOI: https://doi.org/10.1007/s11064-010-0130-6

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