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Metallothioneins Attenuate Methylmercury‐Induced Neurotoxicity in Cultured Astrocytes and Astrocytoma Cells
Author(s) -
YAO CHANG PING,
ALLEN JEFFREY W.,
ASCHNER MICHAEL
Publication year - 1999
Publication title -
annals of the new york academy of sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.712
H-Index - 248
eISSN - 1749-6632
pISSN - 0077-8923
DOI - 10.1111/j.1749-6632.1999.tb07997.x
Subject(s) - astrocyte , transfection , glial fibrillary acidic protein , microbiology and biotechnology , western blot , cell culture , metallothionein , astrocytoma , chemistry , neuroglia , microglia , neurotoxicity , cytotoxicity , biology , glioma , biochemistry , immunology , cancer research , immunohistochemistry , in vitro , toxicity , endocrinology , central nervous system , gene , organic chemistry , inflammation , genetics
Metallothionein‐I (MT‐I) was expressed in neonatal rat primary astrocyte cultures and an astrocytoma cell line by pGFAP‐MT‐I plasmid transfection under the control of the astrocyte‐specific glial fibrillary acidic protein (GFAP) promoter. Following transient transfection of the pGFAP‐MT‐I plasmid, MT‐I mRNA and MT‐I protein levels were determined by Northern blot and immunoprecipitation analyses, respectively. The ability of cells overexpressing MT‐I to withstand acute methylmercury (MeHg) treatment was measured by the release of preloaded Na 2 51 CrO 4 , an indicator of membrane integrity. Transfection with the pGFAP‐MT‐I plasmid led to increased mRNA (2.5‐fold in astrocytes and 7.4‐fold in astrocytomas) and MT‐I protein (2.4‐fold in astrocytes and 4.0‐fold in astrocytomas) levels compared with their respective controls. Increased expression of MT‐I was associated with attenuated release of Na 2 51 CrO 4 upon MeHg (5 μM) treatment. These results demonstrate that MT‐I can be highly expressed both in primary astrocyte cultures and astrocytomas by pGFAP‐MT‐I plasmid transfection, and lend credence to the hypothesis that increased expression of MT‐I affords protection against the cytotoxic effects of MeHg. Taken together, the data suggest that MTs offer effective cellular adaptation to MeHg cytotoxicity.