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P3‐271: Presenilin‐1 (PS1) and amyloid precursor protein (APP) mutations present in mouse models of Alzheimer's disease in their response to γ‐secretase inhibitors and modulators
Author(s) -
Lehmann Stefanie,
Bruening Tanja,
Ness Julia,
Czirr Eva,
Bulic Bruno,
Pietrzik Claus U.,
Weggen Sascha
Publication year - 2009
Publication title -
alzheimer's and dementia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.713
H-Index - 118
eISSN - 1552-5279
pISSN - 1552-5260
DOI - 10.1016/j.jalz.2009.04.942
Subject(s) - presenilin , genetically modified mouse , amyloid precursor protein , chinese hamster ovary cell , gamma secretase , transgene , mutation , phenotype , biology , microbiology and biotechnology , cancer research , alzheimer's disease , medicine , disease , genetics , gene , cell culture
peptides mainly generate two isoform, Aß40 and Aß42 by enzymatic proteolysis of amyloid precursor protein (APP). In particular, the Aß42 is believed to be the major etiologic agent in pathogenesis of AD due to its higher fibrillation or oligomerization properties than that of Aß40. Recently we have established conformation dependent human antibody, B6, which binds to Aß42 fibril, but not to soluble form of Aß42, inhibiting Aß42 fibril formation. Concurrently, we have identified a mimotope of B6, B6-C15, using the PhD.C7C phage library. We chemically synthesized TAT-conjugated B6-C15 peptide, TATB6-C15. This synthetic peptide has inhibitory activity on Aß42 fibrillation. Furthermore, TAT-B6-C15 specifically binds to the oligomer form of Aß42, but not to freshly prepared monomer Aß42 nor its fibril form. In this study, we investigated the effect of this TAT-B6-C15 peptide on Aß40 assembly. Methods: Aß42 or Aß40 was incubated at 37 C in the presence or absence of TAT-B6-C15 peptide. Aß fibrillation was monitored by amyloid specific fluorescence dye, Thioflavin T. To identify the Aß conformers which specifically bound to TAT-B6-C15 peptide, we performed dot blot analysis. Aß conformers were periodically sampled after the onset of Aß40 or 42 fibrillation assay and hand-spotted onto nitrocellulose membrane, followed by incubation with detection probes such as TAT-B6-C15 or anti-Aß antibody. Results: The TAT-B6-C15 peptide exhibited inhibitory effect on Aß42, but not Aß40 fibrillation. Furthermore, the TAT-B6-C15 showed binding activity to the Aß42 prefibrillar oligomer, but not any Aß40 conformers. Conclusions: The mimotope peptide which identified as conformation dependent antibody epitope, specifically binds to prefibrillar oligomers of Aß42, inhibiting Aß42 but not Aß40 fibril formation.