Abstract |
Urea-based beta-amyloid (Abeta) SDS- polyacrylamide gel electrophoresis and immunoblots were used to analyze the generation of Abeta peptides in conditioned medium from primary mouse neurons and a neuroglioma cell line, as well as in human cerebrospinal fluid. A comparable and highly conserved pattern of Abeta peptides, namely, 1-40/42 and carboxyl-terminal-truncated 1-37, 1-38, and 1-39, was found. Besides Abeta1-42, we also observed a consistent elevation of amino-terminal-truncated Abeta2-42 in a detergent-soluble pool in brains of subjects with Alzheimer's disease. Abeta2-42 was also specifically elevated in cerebrospinal fluid samples of Alzheimer's disease patients. To decipher the contribution of potential different gamma- secretases ( presenilins (PSs)) in generating the amino-terminal- and carboxyl-terminal-truncated Abeta peptides, we overexpressed beta-amyloid precursor protein (APP)-trafficking mutants in PS1+/+ and PS1-/- neurons. As compared with APP-WT (primary neurons from control or PS1-deficient mice infected with Semliki Forest virus), PS1-/- neurons and PS1+/+ neurons overexpressing APP-Deltact (a slow-internalizing mutant) show a decrease of all secreted Abeta peptide species, as expected, because this mutant is processed mainly by alpha-secretase. This drop is even more pronounced for the APP-KK construct (APP mutant carrying an endoplasmic reticulum retention motif). Surprisingly, Abeta2-42 is significantly less affected in PS1-/- neurons and in neurons transfected with the endocytosis-deficient APP-Deltact construct. Our data confirm that PS1 is closely involved in the production of Abeta1-40/42 and the carboxyl-terminal-truncated Abeta1-37, Abeta1-38, and Abeta1-39, but the amino-terminal-truncated and carboxyl-terminal-elongated Abeta2-42 seems to be less affected by PS1 deficiency. Moreover, our results indicate that the latter Abeta peptide species could be generated by a beta(Asp/Ala)- secretase activity.
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Authors | J Wiltfang, H Esselmann, P Cupers, M Neumann, H Kretzschmar, M Beyermann, D Schleuder, H Jahn, E Rüther, J Kornhuber, W Annaert, B De Strooper, P Saftig |
Journal | The Journal of biological chemistry
(J Biol Chem)
Vol. 276
Issue 46
Pg. 42645-57
(Nov 16 2001)
ISSN: 0021-9258 [Print] United States |
PMID | 11526104
(Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
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Chemical References |
- Amyloid beta-Peptides
- DNA, Complementary
- Peptide Fragments
- Peptides
- amyloid beta-protein (1-42)
- amyloid beta-protein (2-42)
- Amyloid Precursor Protein Secretases
- Endopeptidases
- Aspartic Acid Endopeptidases
- BACE1 protein, human
- Bace1 protein, mouse
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Topics |
- Aged
- Aged, 80 and over
- Alzheimer Disease
(cerebrospinal fluid, metabolism)
- Amino Acid Sequence
- Amyloid Precursor Protein Secretases
- Amyloid beta-Peptides
(biosynthesis, cerebrospinal fluid, chemistry)
- Animals
- Aspartic Acid Endopeptidases
(metabolism)
- Brain
(metabolism)
- Cell Line
- Cells, Cultured
- DNA, Complementary
(metabolism)
- Electrophoresis, Gel, Two-Dimensional
- Electrophoresis, Polyacrylamide Gel
- Endopeptidases
- Endoplasmic Reticulum
(metabolism)
- Humans
- Immunoblotting
- Mice
- Mice, Knockout
- Middle Aged
- Molecular Sequence Data
- Mutation
- Neurons
(metabolism)
- Peptide Fragments
(biosynthesis, cerebrospinal fluid, chemistry)
- Peptides
(chemistry)
- Precipitin Tests
- Protein Binding
- Protein Structure, Tertiary
- Semliki forest virus
(genetics)
- Sequence Homology, Amino Acid
- Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
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