Faculty Collaboration Database

Antioxidants and ocular cell type differences in cytoprotection from formic acid toxicity in vitro. Toxicol Sci 2004 Nov;82(1):183-92

Date

08/21/2004

Pubmed ID

15319487

DOI

10.1093/toxsci/kfh256

Scopus ID

2-s2.0-8444235011 (requires institutional sign-in at Scopus site)   30 Citations

Abstract

Retinal photoreceptors and retinal pigment epithelial (RPE) cells are among the cell types that are sensitive to poisoning with methanol and its toxic metabolite formic acid. When exposed to formic acid in vitro, cultured cell lines from photoreceptors (661W) and the RPE (ARPE-19) were previously shown to accumulate similar levels of formate, but cytotoxic effects are greater in 661W cells. Here catalase and glutathione were analyzed in the two retinal cell lines to determine whether differences in these antioxidant systems contributed to cell-type-specific differences in cytotoxicity. Cells were exposed to formic acid (pH 6.8) in the culture medium in the presence or absence of a catalase activity inhibitor, 3-amino-1,2,4-triazole (AT), or a glutathione synthesis inhibitor, buthionine L-sulfoximine (BSO). Catalase protein, catalase enzyme activity, glutathione, glutathione peroxidase activity, cellular ATP, and cytotoxicity were analyzed. Compared to ARPE-19, 661W cells show lower antioxidant levels: 50% less glutathione, glutathione peroxidase and catalase protein, and 90% less catalase enzyme activity. In both cell types, formic acid treatment produced decreases in glutathione and glutathione peroxidase, and glutathione synthesis inhibition with BSO produced greater ATP depletion and cytotoxicity than formic acid treatment alone. In contrast, formate exposure produced decreases in catalase protein and activity in 661W cells, but increases in activity in ARPE-19. Treatment with the catalase inhibitor AT increased the formate sensitivity only of the ARPE-19 cells. ARPE-19 cells, therefore, may be less susceptible to formate toxicity due to higher levels of antioxidants, especially catalase, which increases on formate treatment and which has a significant cytoprotective effect for the RPE cell line.

Author List

Treichel JL, Henry MM, Skumatz CM, Eells JT, Burke JM

Author

Janis Eells PhD Professor in the Biomedical Sciences department at University of Wisconsin - Milwaukee

MESH terms used to index this publication - Major topics in bold

Amitrole
Antioxidants
Buthionine Sulfoximine
Catalase
Cells, Cultured
Cytoprotection
Drug Combinations
Enzyme Inhibitors
Formates
Glutathione
Glutathione Peroxidase
Humans
Photoreceptor Cells
Pigment Epithelium of Eye