Long amyloid beta-protein secreted from wild-type human neuroblastoma IMR-32 cells.
The 39- to 43-amino acid amyloid beta-protein (A beta) is deposited as amyloid in Alzheimer's disease. Recent studies have suggested that short A beta (A beta 39 or A beta 40) and long A beta (A beta 42 or A beta 43) play different roles in Alzheimer-type pathology. However, little attempt has been made to investigate the cellular mechanisms underlying the generation of short and long A beta individually. In the present report, we first measured the amount of short and long A beta that are secreted from wild-type human and rodent cells with neuron- or glia-like properties using highly sensitive sandwich-ELISAs that discriminate long A beta from short A beta. The results showed that long A beta secreted by all cells constitutes approximately 10% of the total A beta. To identify the molecular species of long A beta, we next isolated the A beta species secreted from human neuroblastoma IMR-32 cells by affinity chromatography, gel-filtration HPLC, and reverse-phase HPLC. Mass spectrometric analysis demonstrated unequivocally that IMR-32 cells produce A beta 1-42 together with A beta 1-37, A beta 1-38, A beta 1-39, and most predominantly, A beta 1-40. Finally, to investigate the cellular mechanisms that generate A beta 1-42, we studied the effects of brefeldin A and monensin on the production of A beta 1-40 and A beta 1-42 in IMR-32 cells. These reagents reduced the production of both A beta 1-40 and A beta 1-42 simultaneously in a concentration-dependent manner.(ABSTRACT TRUNCATED AT 250 WORDS)
Asami-Odaka
A
A
Discovery Research Laboratories I, Takeda Chemical Industries, Ltd., Ibaraki, Japan.
Ishibashi
Y
Y
Kikuchi
T
T
Kitada
C
C
Suzuki
N
N
D016229:Amyloid beta-Peptides / Q000302:isolation & purification / Q000378:metabolism*; D016564:Amyloid beta-Protein Precursor / Q000378:metabolism; D000818:Animals; D002851:Chromatography, High Pressure Liquid; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D051379:Mice; D009447:Neuroblastoma; D011499:Protein Processing, Post-Translational; D014407:Tumor Cells, Cultured
D016229:Amyloid beta-Peptides; D016564:Amyloid beta-Protein Precursor