Structural change and degradation of cytoskeleton due to the acrolein conjugation with vimentin and actin during brain infarction

We have found recently that dendritic spine extension is inhibited through acrolein conjugation with alpha- and beta-tubulin proteins during brain infarction. In this current study, we looked for other acrolein-conjugated proteins in the 100,000g precipitate fraction, to clarify how cytoskeleton structure is modified by acrolein. Acrolein-conjugated proteins were sought from acrolein-treated mouse FM3A and Neuro2a cells and from tissues isolated from mouse brain infarction. It was found that vimentin was conjugated with acrolein, and the conjugated amino acid residue was Cys328, which is the only Cys residue in vimentin. It was also found that Cys207, 257, 285, and Lys118 in actin, another cytoskeleton protein, were conjugated with acrolein. The structure and localization of vimentin and actin filaments were changed greatly in infarct brain in photochemically induced thrombosis model mice and in acrolein-treated Neuro2a cells. In addition, degradation of cytoskeleton proteins was accelerated in the order vimentin > tubulin > actin in mouse brain infarction. These findings indicate that a dysfunction of the cytoskeleton by acrolein is strongly involved in the tissue damage during brain infarction, together with the apoptosis caused by glyceraldehyde-3-phosphate dehydrogenase and protein degradation by matrix metalloproteinase-9.