TY - JOUR T1 - Chaperone Hsp90 Mobilization and Hydralazine Cytoprotection against Acrolein-Induced Carbonyl Stress JF - Molecular Pharmacology JO - Mol Pharmacol DO - 10.1124/mol.112.078956 SP - mol.112.078956 AU - Philip Cyril Burcham AU - Albert Raso AU - Lisa M Kaminskas Y1 - 2012/01/01 UR - http://molpharm.aspetjournals.org/content/early/2012/08/06/mol.112.078956.abstract N2 - Toxic carbonyls such as acrolein participate in many degenerative diseases. While the nucleophilic vasodilatory drug hydralazine readily traps such species under "test tube" conditions, whether these reactions adequately explain its efficacy in animal models of carbonyl-mediated disease is uncertain. We have previously shown that hydralazine attacks carbonyl-adducted proteins in an "adduct-trapping" reaction which appears to take precedence over direct "carbonyl-sequestering" reactions, but how this reaction conferred cytoprotection was unclear. This study explored the possibility that by increasing the bulkiness of acrolein-adducted proteins, adduct-trapping might alter the redistribution of chaperones to damaged cytoskeletal proteins that are known targets for acrolein. Using A549 lung adenocarcinoma cells, the levels of chaperones Hsp-40, -70, -90 and -110 were measured in intermediate filament extracts prepared following a 3 h exposure to acrolein. Exposure to acrolein alone modestly increased the levels of all four chaperones. Co-exposure to hydralazine (10 to 100 μM) strongly suppressed cell ATP loss while producing strong adduct-trapping in intermediate filaments. Most strikingly, hydralazine selectively boosted the levels of cytoskeletal-associated Hsp90, including a high-mass species which was sensitive to the Hsp90 inhibitor 17-AAG. Biochemical fractionation of acrolein- and hydralazine-treated cells revealed that hydralazine likely promoted Hsp90 migration from cytosol into other subcellular compartments. A role for Hsp90 mobilization in cytoprotection was confirmed by the finding that brief heat shock treatment suppressed acute acrolein toxicity in A549 cells. Collectively, these findings suggest that by increasing the steric bulk of carbonyl-adducted proteins, adduct-trapping drugs trigger the intracellular mobilization of the key molecular chaperone Hsp90. ER -