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Expression and regulation of L‐cystine transporter, system x c − , in the newly developed rat retinal Müller cell line (TR‐MUL)
Author(s) -
Tomi Masatoshi,
Funaki Takeshi,
Abukawa Hayato,
Katayama Kazunori,
Kondo Tetsu,
Ohtsuki Sumio,
Ueda Masatsugu,
Obinata Masuo,
Terasaki Tetsuya,
Hosoya KenIchi
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.10253
Subject(s) - cystine , biology , glutamine , microbiology and biotechnology , cell culture , glutathione , biochemistry , amino acid transporter , in vitro , transporter , amino acid , cysteine , gene , enzyme , genetics
The purpose of the present study was to elucidate the expression and regulation of the L‐cystine transporter, system x c − , in Müller cells. In this study, newly developed conditionally immortalized rat Müller cell lines (TR‐MUL) from transgenic rats harboring the temperature‐sensitive SV 40 large T‐antigen gene were used as an in vitro model. TR‐MUL cells express large T‐antigen and grow well at 33°C with a doubling time of 30 h, but do not grow at 39°C. TR‐MUL cells express typical Müller cell markers such as S‐100, glutamine synthetase, and EAAT1/GLAST, whereas EAAT2/GLT‐1 and EAAT5 are not detected. TR‐MUL cells also exhibit little or no expression of glial fibrillary acidic protein. We found that TR‐MUL5 cells exhibited [ 14 C]L‐cystine uptake activity and expressed xCT and 4F2hc, which involve system x c − . The uptake of [ 14 C]L‐cystine was significantly inhibited by L‐glutamic acid and L‐aspartic acid, whereas L‐leucine had no effect. Following diethyl maleate (DEM) treatment, the glutathione concentration in TR‐MUL5 cells was reduced in the first 24 h, then gradually recovered for more than 24 h. The L‐cystine uptake rate and the xCT expression level in TR‐MUL5 cells were enhanced by DEM treatment. In contrast, the 4F2hc expression level was unchanged. In conclusion, TR‐MUL cells have the properties of Müller cells and exhibit system x c − ‐mediated L‐cystine uptake activity. The oxidative stress conditions following DEM treatment activate L‐cystine transport in TR‐MUL cells due to the enhanced transcription of the xCT gene. GLIA 9999:000–000, 2003. © 2003 Wiley‐Liss, Inc.