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Glutamate‐modulated production of GABA in immortalized astrocytes transduced by a glutamic acid decarboxylase‐expressing retrovirus
Author(s) -
Sacchettoni S.A.,
Benchaibi M.,
Sindou M.,
Belin M.F.,
Jacquemont B.
Publication year - 1998
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/(sici)1098-1136(199801)22:1<86::aid-glia8>3.0.co;2-6
Subject(s) - glutamate decarboxylase , biology , glutamate receptor , astrocyte , immortalised cell line , glutaminase , cell culture , glutamine synthetase , glutamine , microbiology and biotechnology , neuroglia , glutamic acid , biochemistry , cell , enzyme , amino acid , central nervous system , neuroscience , genetics , receptor
Replication‐defective Moloney murine leukemia virus expressing the GAD67 gene under the control of the GFAP promoter was produced using selected clones of a fibroblast‐packaging cell line. A spontaneously immortalized astrocyte cell line was infected with this virus and cellular clones expressing GAD67 selected. Astrocyte and fibroblast clones expressed functional GAD (detected by glutamic acid decarboxylation), but only fibroblasts were able to also produce GABA in the extracellular medium. When exposed to 200 μM glutamate, despite an observed difference in the rates of glutamate accumulation in control and GAD67‐expressing astrocytes, similar proportions of glutamate taken up were detected. In GAD67‐expressing astrocytes, the glutamate was mainly converted into GABA, suggesting GAD transgene activity to be dominant over other glutamate metabolic pathways, such as glutamine synthetase and glutamate dehydrogenase. Moreover, rapid GABA release into the cell medium was also observed, suggesting the involvement of reverse GABA transporters. The use of the GFAP promoter might be able to take advantage of its activation in response to factors inducing reactive gliosis observed in pathological insults. GAD67‐expressing astrocytes might therefore be used for future grafting in pathological situations in which an excess of glutamate results in neuronal dysfunction or cell death. GLIA 22:86–93, 1998. © 1998 Wiley‐Liss, Inc.