Fig. 2

Increased sAPPα levels in meprin β ko mice. a-c Soluble and membrane fractions of brain lysates from meprin β ko (Mep1b ^−/−) (n = 6) and wt (n = 6) mice were probed with antibodies specific for sAPPα (7A6), sAPPβ (192wt) (Additional file 1), full-length APP (22C11) and actin or tubulin as loading controls (note that only representative n = 3 for each is shown). b Note that endogenous sAPPα levels were increased in the absence of meprin β, indicating a changed APP processing profile in Mep1b ^−/− compared to wt mice. d Aβ40 levels of supernatants of primary cortical neurons of wt (n = 3) and meprin ko mice (n = 6) were detected via Meso Scale ELISA using sulfo-tagged 4G8 antibody. Meprin β ko mice showed approximately 13 % less Aβ40 (normalized to total protein of lysates). e Urea gel of immunoprecipitated Aβ (using IC16 antibody) of supernatants of primary cortical neurons of wt and meprin β ko mice infected with a recombinant adenovirus expressing APP695. Lysates showed a decrease in mature APP for meprin β ko (CT15 antibody). f Quantification of Aβ2-40 levels (normalized to tubulin of lysates) of (e) showed a decrease of approximately 50 % in meprin β ko neurons (n = 2)