Research

Expression of SOD1 G93A or wild-type SOD1 in primary cultures of astrocytes down-regulates the glutamate transporter GLT-1 : lack of involvement of oxidative stress


Reference:

Tortarolo, M., Crossthwaite, A. J., Conforti, L., Spencer, J. P., Williams, R. J., Bendotti, C. and Rattray, M., 2004. Expression of SOD1 G93A or wild-type SOD1 in primary cultures of astrocytes down-regulates the glutamate transporter GLT-1 : lack of involvement of oxidative stress. Journal of Neurochemistry, 88 (2), pp. 481-93.

Related documents:

This repository does not currently have the full-text of this item.
You may be able to access a copy if URLs are provided below.

Official URL:

http://dx.doi.org/10.1046/j.1471-4159.2003.02208.x

Abstract

Glutamate excitotoxicity is implicated in the aetiology of amyotrophic lateral sclerosis (ALS) with impairment of glutamate transport into astrocytes a possible cause of glutamate-induced injury to motor neurons. It is possible that mutations of Cu/Zn superoxide dismutase (SOD1), responsible for about 20% of familial ALS, down-regulates glutamate transporters via oxidative stress. We transfected primary mouse astrocytes to investigate the effect of the FALS-linked mutant hSOD1(G93A) and wild-type SOD1 (hSOD1wt) on the glutamate uptake system. Using western blotting, immunocytochemistry and RT-PCR it was shown that expression of either hSOD1(G93A) or hSOD1wt in astrocytes produced down-regulation of the levels of a glutamate transporter GLT-1, without alterations in its mRNA level. hSOD1(G93A) or hSOD1wt expression caused a decrease of the monomeric form of GLT-1 without increasing oxidative multimers of GLT-1. The effects were selective to GLT-1, since another glutamate transporter GLAST protein and mRNA levels were not altered. Reflecting the decrease in GLT-1 protein, [3H]d-aspartate uptake was reduced in cultures expressing hSOD1(G93A) or hSOD1wt. The hSOD1-induced decline in GLT-1 protein and [3H]d-aspartate uptake was not blocked by the antioxidant Trolox nor potentiated by antioxidant depletion using catalase and glutathione peroxidase inhibitors. Measurement of 2',7'-dichlorofluorescein (DCF)-induced fluorescence revealed that expression of hSOD1(G93A) or hSOD1wt in astrocytes does not lead to detectable increase of intracellular reactive oxygen species. This study suggests that levels of GLT-1 protein in astrocytes are reduced rapidly by overexpression of hSOD1, and is due to a property shared between the wild-type and G93A mutant form, but does not involve the production of intracellular oxidative stress.

Details

Item Type Articles
CreatorsTortarolo, M., Crossthwaite, A. J., Conforti, L., Spencer, J. P., Williams, R. J., Bendotti, C. and Rattray, M.
DOI10.1046/j.1471-4159.2003.02208.x
DepartmentsFaculty of Science > Biology & Biochemistry
RefereedYes
StatusPublished
ID Code30546

Export

Actions (login required)

View Item