Figure 5
Characterization of the effect of amylin on amyloid precursor protein (APP) processing and BACE1. (a) Detection of full-length APP (fAPP) and APP processed products by 6E10 antibody in western blotting in brain homogenates from Tg2576 mice treated with phosphate-buffered saline (PBS) or amylin (n=6 per group), and (b) quantitation of the results (mean±s.e.) are shown. Although there were no differences in the levels fAPP and secreted APP cleaved by α secretase (sAPPα) between PBS control and the amylin treatment, there was an increase in C99 fragment from APP cleaved by BACE1 in the brains treated with amylin compared with PBS treatment (*P=0.004). (c) In vitro assay using purified BACE1 showed that amylin significantly inhibited BACE1 activity, but pramlintide had little inhibition for BACE1. The concentration of amylin necessary to inhibit 50% BACE1 activity (IC50) in this assay is 6.9 μM (d).
