Abstract
Malonate, an inhibitor of mitochondrial complex II, is a widely used toxin to study neurodegeneration in Huntington's disease and ischemic stroke. We have shown previously that malonate increased reactive oxygen species (ROS) production in human SH-SY5Y neuroblastoma cells, leading to oxidative stress, cytochrome c release, and apoptotic cell death. Expression of a green fluorescent protein-Bax fusion protein in SH-SY5Y neuroblastoma cells demonstrated a Bax redistribution from the cytosol to mitochondria after 12 to 24 h of malonate treatment that coincided with mitochondrial potential collapse and chromatin condensation. Inhibition of Bax translocation using furosemide, as well as Bax gene deletion, afforded significant protection against malonate-induced apoptosis. Further experiments revealed that malonate induced a prominent increase in the level of activated p38 mitogen-activated protein (MAP) kinase and that treatment with the p38 MAP kinase inhibitor SKF86002 potently blocked malonate-induced Bax translocation and apoptosis. Treatment with vitamin E diminished ROS production, reduced the activation status of p38 MAP kinase, inhibited Bax translocation, and protected against malonate-induced apoptosis. Our data suggest that malonate-induced ROS production and subsequent p38 MAP kinase activation mediates the activation of the pro-apoptotic Bax protein to induce mitochondrial membrane permeabilization and neuronal apoptosis.
Footnotes
-
This study was supported by SAF2002-04721 and SAF2005-07919-C02-01 from Comisión Interministerial de Ciencia y Tecnologica and 04005-00 Consejería de Sanidad from Junta de Comunidades de Castilla La Mancha (to J.J.) Ministerio de Sanidad y Consumo, Fundació La Caixa and Generalitat de Catalunya (to J.X.C.) and Science Foundation Ireland grant 03/RP1/B344 (to J.H.M.P.). M.G.-L. and F.J.F.-G. are fellows from Junta de Comunidades de Castilla-La Mancha.
-
Article, publication date, and citation information can be found at http://molpharm.aspetjournals.org.
-
doi:10.1124/mol.106.030718.
-
ABBREVIATIONS: ΔΨm, mitochondrial transmembrane potential; GFP, green fluorescent protein; MDA, malondialdehyde; MEF, mouse embryonic fibroblasts; ROS, reactive oxygen species; TMRE, tetramethylrhodamine ethyl ester.
- Received September 8, 2006.
- Accepted December 15, 2006.
- The American Society for Pharmacology and Experimental Therapeutics
MolPharm articles become freely available 12 months after publication, and remain freely available for 5 years.Non-open access articles that fall outside this five year window are available only to institutional subscribers and current ASPET members, or through the article purchase feature at the bottom of the page.
|