title: Formaldehyde induces rapid glutathione export from viable oligodendroglial OLN-93 cells.
abstract: Formaldehyde is a neurotoxic environmental pollutant that can also be produced in the body by certain enzymatic reactions. To test for the potential consequences of an exposure of oligodendrocytes to formaldehyde, we used OLN-93 cells as a model system. Treatment with formaldehyde altered the cellular glutathione (GSH) content of these cells by inducing a rapid time- and concentration-dependent export of GSH. Half-maximal effects were observed for a formaldehyde concentration of about 0.2 mM. While the basal GSH efflux from OLN-93 cells was negligible even when the cellular GSH content was doubled by pre-incubation of the cells with cadmium chloride, the formaldehyde-stimulated export increased almost proportionally to the cellular GSH content. In addition, the stimulated GSH export required the presence of formaldehyde and was almost completely abolished after removal of the aldehyde. Analysis of kinetic parameters of the formaldehyde-induced GSH export revealed similar K(m) and V(max) values of around 100 nmol/mg and 40 nmol/(hmg), respectively, for both OLN-93 cells and cultured astrocytes. The transporter responsible for the formaldehyde-induced GSH export from OLN-93 cells is most likely the multidrug resistance protein 1 (Mrp1), since this transporter is expressed in these cells and since the inhibitor MK571 completely prevented the formaldehyde-induced GSH export. The rapid export of GSH from formaldehyde-treated viable oligodendroglial cells is likely to compromise the cellular antioxidative and detoxification potential which may contribute to the known neurotoxicity of formaldehyde.
authors.affiliation: Centre for Biomolecular Interactions Bremen, University of Bremen, P.O. Box 330440, D-28334 Bremen, Germany.
authors.forename: Ketki
authors.initials: K
authors.lastname: Tulpule
authors.forename: Maike M
authors.initials: MM
authors.lastname: Schmidt
authors.forename: Karolin
authors.initials: K
authors.lastname: Boecker
authors.forename: Olaf
authors.initials: O
authors.lastname: Goldbaum
authors.forename: Christiane
authors.initials: C
authors.lastname: Richter-Landsberg
authors.forename: Ralf
authors.initials: R
authors.lastname: Dringen
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000037:antagonists & inhibitors / Q000378:metabolism; D000818:Animals; D001253:Astrocytes / Q000187:drug effects / Q000378:metabolism; D001693:Biological Transport, Active / Q000187:drug effects; D002461:Cell Line, Transformed / Q000187:drug effects / Q000378:metabolism; D002478:Cells, Cultured / Q000187:drug effects / Q000378:metabolism; D005557:Formaldehyde / Q000494:pharmacology*; D005978:Glutathione / Q000378:metabolism*; D009419:Nerve Tissue Proteins / Q000378:metabolism; D009836:Oligodendroglia / Q000187:drug effects* / Q000378:metabolism; D061251:Primary Cell Culture; D011422:Propionates / Q000494:pharmacology; D011804:Quinolines / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D009419:Nerve Tissue Proteins; D011422:Propionates; D011804:Quinolines; D005557:Formaldehyde; C059141:verlukast; D005978:Glutathione