Evoked expression of the glutamate transporter GLT-1C in retinal ganglion cells in human glaucoma and in a rat model

Sullivan, Robert K. P., WoldeMussie, Elizabeth, Macnab, Lauren, Ruiz, Guadalupe and Pow, David V. (2006) Evoked expression of the glutamate transporter GLT-1C in retinal ganglion cells in human glaucoma and in a rat model. Investigative Ophthalmology and Visual Science, 47 9: 3853-3859. doi:10.1167/iovs.06-0231


Author Sullivan, Robert K. P.
WoldeMussie, Elizabeth
Macnab, Lauren
Ruiz, Guadalupe
Pow, David V.
Title Evoked expression of the glutamate transporter GLT-1C in retinal ganglion cells in human glaucoma and in a rat model
Journal name Investigative Ophthalmology and Visual Science   Check publisher's open access policy
ISSN 0146-0404
1552-5783
Publication date 2006-09
Sub-type Article (original research)
DOI 10.1167/iovs.06-0231
Volume 47
Issue 9
Start page 3853
End page 3859
Total pages 7
Place of publication Rockville, MD, U.S.A.
Publisher Association for Research in Vision and Ophthalmology
Language eng
Subject 1113 Ophthalmology and Optometry
Formatted abstract
Purpose
Glaucoma is a common disease of the eye, a key characteristic consequence of which is the death of retinal ganglion cells. The cause of this loss is unknown, though glutamate-mediated toxicity has been implicated. Glutamate transporters are key regulators of glutamate; therefore, the purpose of the study was to determine whether unusual excitation is associated with unusual expression of one or more transporters.

Methods
The expression of a splice variant of the glutamate transporter GLT-1 (EAAT2) was examined in normal and glaucomatous retinas from humans and rats.

Results
In normal eyes of humans and rats, GLT-1c was expressed only in photoreceptors. In glaucoma, there was additional robust expression of GLT-1c in retinal ganglion cells, including occasional displaced ganglion cells. Conversely, cells such as displaced amacrine cells and amacrine cells were unlabeled.

Conclusions
The induction of GLT-1c expression by retinal ganglion cells supports the notion that an anomaly or anomalies in glutamate homeostasis may be evident in glaucoma and that such anomalies selectively influence retinal ganglion cells. By analogy to in vitro experiments in which elevated glutamate levels induce expression of glutamate transporters, the authors hypothesize that expression of GLT-1c may represent an attempt by retinal ganglion cells to protect themselves against elevated levels of glutamate. Such anomalies in glutamate levels cannot be restricted to the ganglion cell layer, as this would not have affected displaced ganglion cells. GLT-1c may be a useful indicator of the extent of stress of the retinal ganglion cells and thus a tool for examining outcomes of potential therapeutic and experimental interventions.
Copyright © Association for Research in Vision and Ophthalmology
Keyword Glutamate transporter
Glutamate transporter 1c
Unclassified drug
Apoptosis regulatory protein
Excitatory amino acid transporter 2
Glutamic acid
MOAP1 protein
Mouse
Signal transducing adaptor protein
Glaucoma
Retinal ganglion cells
Q-Index Code C1

Document type: Journal Article
Sub-type: Article (original research)
Collections: Excellence in Research Australia (ERA) - Collection
Queensland Brain Institute Publications
 
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Created: Mon, 18 Jan 2010, 12:48:49 EST by Jon Swabey on behalf of Queensland Brain Institute