Specific inhibitor for prolyl endopeptidase suppresses the generation of amyloid beta protein in NG108-15 cells.
A potent and specific prolyl endopeptidase inhibitor, JTP-4819, was used to investigate the role of prolyl endopeptidase in the generation of amyloid beta protein (A beta) from APP by NG108-15 cells. Synthetic substrates, 7-(succinyl-Ile-Ala)-4-methylcoumarinamide and Z(Val-Lys-Met)-4-methylcoumarinamide, respectively, corresponding to the C-terminal and N-terminal portions of A beta, were cleaved by NG108-15 cell lysates. Cleavage of the C-terminal portion, but not the N-terminal, was inhibited by JTP-4819 (IC50 = 0.6 nM). Western blot analysis showed that the A beta level in the culture medium of NG108-15 cells was increased by serum deprivation. JTP-4819 caused concentration (>10(-9) M)- and time-dependent inhibition of this serum deprivation-induced increase of A beta without having any effect on the level of the secretory form of APP. Using both specific anti-A beta (1-40) and anti-A beta (1-42) antisera, the A beta that increased with serum deprivation was confirmed to be A beta (1-40), suggesting that it might be produced by conversion of A beta (1-42) to A beta (1-40). These findings indicate that prolyl endopeptidase may be a key enzyme in the production of A beta by NG108-15 cells and that A beta secretion can be modulated by a prolyl endopeptidase inhibitor.
Shinoda
M
M
Department of Neurochemistry, National Institute of Neuroscience, Kodaira, Tokyo, Japan.
Toide
K
K
Ohsawa
I
I
Kohsaka
S
S
D016229:Amyloid beta-Peptides / Q000096:biosynthesis*; D000818:Animals; D005910:Glioma; D006822:Hybrid Cells; D007700:Kinetics; D051379:Mice; D009447:Neuroblastoma; D000085822:Prolyl Oligopeptidases; D011759:Pyrrolidines / Q000494:pharmacology*; D051381:Rats; D012697:Serine Endopeptidases / Q000378:metabolism*; D015842:Serine Proteinase Inhibitors / Q000494:pharmacology*; D013379:Substrate Specificity
D016229:Amyloid beta-Peptides; D011759:Pyrrolidines; D015842:Serine Proteinase Inhibitors; C094211:JTP 4819; D012697:Serine Endopeptidases; D000085822:Prolyl Oligopeptidases