Determination of the environmental factors involved in neurodegenerative diseases has been elusive. Methylmercury and β-N-methylamino-L-alanine (BMAA) have both been implicated in this role. Exposure of primary cortical cultures to these compounds independently induced concentration-dependent neurotoxicity. Importantly, concentrations of BMAA (10–100 μM) that caused no toxicity alone potentiated methylmercury (3 μM) toxicity. In addition, concentrations of BMAA and methylmercury that had no effect by themselves on the main cellular antioxidant glutathione together decreased glutathione levels. Furthermore, the combined toxicity of methylmercury and BMAA was attenuated by the cell permeant form of glutathione, glutathione monoethyl ester. The results indicate a synergistic toxic effect of the environmental neurotoxins BMAA and methylmercury, and that the interaction is at the level of glutathione depletion.
Department of Biomedical Sciences, Marquette University, Milwaukee, Wisconsin, USA
Correspondence to Dr Doug Lobner, Department of Biomedical Sciences, Marquette University, 561N. 15th Street, Rm 426, Milwaukee, WI 53233, USA Tel: +1 414 288 6569; fax: +1 414 288 6564; e-mail: Doug.Lobner@marquette.edu
Received November 26, 2011
Accepted November 30, 2011