Glutamate transporter expression and function in human glial progenitors
Article first published online: 5 NOV 2003
Copyright © 2003 Wiley-Liss, Inc.
Volume 45, Issue 2, pages 133–143, 15 January 2004
How to Cite
Maragakis, N. J., Dietrich, J., Wong, V., Xue, H., Mayer-Proschel, M., Rao, M. S. and Rothstein, J. D. (2004), Glutamate transporter expression and function in human glial progenitors. Glia, 45: 133–143. doi: 10.1002/glia.10310
- Issue published online: 3 JAN 2004
- Article first published online: 5 NOV 2003
- Manuscript Accepted: 21 JUL 2003
- Manuscript Received: 5 MAY 2003
- National Institutes of Neurologic Disorders and Stroke. Grant Number: NS02131
- Muscular Dystrophy Association
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.