Enhanced generation of intracellular Abeta42 amyloid peptide by mutation of presenilins PS1 and PS2.

Abstract

The accumulation of amyloid beta-peptide (Abeta) in the brain is a critical pathological process in Alzheimer's disease (AD). Recent studies have implicated intracellular Abeta in neurodegeneration in AD. To investigate the generation of intracellular Abeta, we established human neuroblastoma SH-SY5Y cells stably expressing wild-type amyloid precursor protein (APP), Swedish mutant APP, APP plus presenilin 1 (PS1) and presenilin 2 (PS2; wild-type or familial AD-associated mutant), and quantified intracellular Abeta40 and Abeta42 in formic acid extracts by sensitive Western blotting. Levels of both intracellular Abeta40 and Abeta42 were 2-3-fold higher in cells expressing Swedish APP, compared with those expressing wild-type APP. Intracellular Abeta42/Abeta40 ratios were approximately 0.5 in these cells. These ratios were increased markedly in cells expressing mutant PS1 or PS2 compared with those expressing their wild-type counterparts, consistent with the observed changes in secreted Abeta42/Abeta40 ratios. High total levels of intracellular Abeta were observed in cells expressing mutant PS2 because of a marked elevation of Abeta42. Immunofluorescence staining additionally revealed more intense Abeta42 immunoreactivity in mutant PS2-expressing cells than in wild-type cells, which was partially colocalized with immunoreactivity for the trans-Golgi network and endosomes. The data collectively indicate that PS mutations promote the accumulation of intracellular Abeta42, which appears to be localized in multiple subcellular compartments.

• Authors: Kazuya Takeda, Wataru Araki, Takeshi Tabira
• Journal: The European journal of neuroscience (Eur J Neurosci) Vol. 19 Issue 2 Pg. 258-264 (Jan 2004) ISSN: 0953-816X [Print] France
• PMID: 14725619 (Publication Type: Comparative Study, Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Amyloid beta-Peptides
• Membrane Proteins
• PSEN1 protein, human
• PSEN2 protein, human
• Peptide Fragments
• Presenilin-1
• Presenilin-2
• amyloid beta-protein (1-42)

Topics

• Amyloid beta-Peptides (biosynthesis, genetics)
• Cell Line, Tumor
• Humans
• Intracellular Fluid (metabolism)
• Membrane Proteins (genetics)
• Mutation (genetics)
• Peptide Fragments (biosynthesis, genetics)
• Presenilin-1
• Presenilin-2