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Updated: Aug 30, 2026

A11-positive β-amyloid Oligomer Preparation and Assessment Using Dot Blotting Analysis
Published on: May 22, 2018
Enhancement of proteolytic processing of the beta-amyloid precursor protein by hyperforin
Bettina Froestl1, Barbara Steiner, Walter E Müller
1Department of Pharmacology, Biocenter, University of Frankfurt, Marie-Curie-Str. 9, D-60439 Frankfurt, Germany.
Abstract:
We studied the effect of hyperforin, a component of St. John's wort (Hypericum perforatum) extracts, on the processing of the amyloid precursor protein (APP) in rat pheochromocytoma PC12 cells, stably transfected with human wildtype APP. We observed transiently increased release of secretory APP fragments upon hyperforin treatment. Unique features, like a strong reduction of intracellular APP and the time course of soluble APP release, distinguished the effects of hyperforin from those of alkalizing agents and phorbol esters, well known activators of secretory processing of APP. Carbonyl cyanide 4-(trifluoromethoxy)phenylhydrazone (FCCP), a protonophore, induced an almost identical decrease in intracellular pH in PC12 cells as does hyperforin. Despite this, FCCP induced a less pronounced release of soluble APP fragments and only slightly reduced intracellular APP levels. These results suggest that hyperforin is an activator of secretory processing of APP with a novel mechanism of action not solely dependent on its effects on intracellular pH.
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