Lithium inhibits amyloid secretion in COS7 cells transfected with amyloid precursor protein C100

To examine the regulation of amyloid secretion in more detail, Abeta sandwich ELISAs with high sensitivity and specificity were developed. Using this technique, we measured Abeta secreted from COS7 cells transiently transfected with APP C100 in the presence of LiCl, a potent glycogen synthase kinase (GSK)-3beta inhibitor. We found that both Abetax-40 and Abetax-42 secretion were reduced by LiCl treatment in a dose-dependent manner. Diminished amyloid secretion was associated with GSK-3beta activity. These results suggest that GSK-3beta might function as a possible mediator for regulating both amyloid deposition and tau pathology in Alzheimer's disease (AD), and that lithium should be re-evaluated as a candidate reagent for preventing AD pathology.