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Glutamate transporter expression and function in human glial progenitors
Author(s) -
Maragakis Nicholas J.,
Dietrich Joerg,
Wong Victor,
Xue Haipeng,
MayerProschel Margot,
Rao Mahendra S.,
Rothstein Jeffrey D.
Publication year - 2003
Publication title -
glia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.954
H-Index - 164
eISSN - 1098-1136
pISSN - 0894-1491
DOI - 10.1002/glia.10310
Subject(s) - astrocyte , glutamate receptor , biology , neuroglia , microbiology and biotechnology , glutamate aspartate transporter , transporter , progenitor cell , neurotransmitter , downregulation and upregulation , neuroscience , biochemistry , central nervous system , stem cell , excitatory amino acid transporter , gene , receptor
Glutamate is the major neurotransmitter of the brain, whose extracellular levels are tightly controlled by glutamate transporters. Five glutamate transporters in the human brain (EAAT1–5) are present on both astroglia and neurons. We characterize the profile of three different human astroglial progenitors in vitro: human glial restricted precursors (HGRP), human astrocyte precursors (HAPC), and early‐differentiated astrocytes. EAAT 1, EAAT3, and EAAT4 are all expressed in GRPs with a subsequent upregulation of EAAT1 following differentiation of GRPs into GRP‐derived astrocytes in the presence of bone morphogenic protein (BMP‐4). This corresponds to a significant increase in the glutamate transport capacity of these cells. EAAT2, the transporter responsible for the bulk of glutamate transport in the adult brain, is not expressed as a full‐length protein, nor does it appear to have functional significance (as determined by the EAAT2 inhibitor dihydrokainate) in these precursors. A splice variant of EAAT2, termed EAAT2b, does appear to be present in low levels, however. EAAT3 and EAAT4 expression is reduced as glial maturation progresses both in astrocyte precursors and early‐differentiated astrocytes and is consistent with their role in adult tissues as primarily neuronal glutamate transporters. These human glial precursors offer several advantages as tools for understanding glial biology because they can be passaged extensively in the presence of mitogens, afford the potential to study the temporal changes in glutamate transporter expression in a tightly controlled fashion, and are cultured in the absence of neuronal coculture, allowing for the independent study of astroglial biology. © 2003 Wiley‐Liss, Inc.