New protease inhibitors prevent gamma-secretase-mediated production of A beta 40/42 without affecting Notch cleavage

We have designed new non-peptidic potential inhibitors of gamma -secretase and examined their ability to prevent production of amyloid-beta 40 (A beta 40) and A beta 42 by human cells expressing wild-type and Swedish-mutant b eta -amyloid precursor protein (beta APP). Here we identify three such agen ts that markedly reduce recovery of both A beta 40 and A beta 42 produced b y both cell lines, and increase that of C99 and C83, the carboxy-terminal f ragments of beta APP that are derived from beta -and alpha -secretase, resp ectively, Furthermore, we show that these inhibitors do not affect endoprot eolysis of endogenous or overexpressed presenilins. These inhibitors are to tally unable to affect the m Delta Enotch-1 cleavage that leads to generati on of the Notch intracellular domain (NICD). These represent the first non- peptidic inhibitors that are able to prevent gamma -secretase cleavage of b eta APP without affecting processing of m Delta Enotch-1 or endoproteolysis of presenilins. The distinction between these two proteolytic events, whic h are both prevented by disruption of presenilin genes, indicates that alth ough they are intimately linked with beta APP and Notch maturation, preseni lins are probably involved in the control of maturation processes upstream of enzymes that cleave gamma -secretase and Notch.