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O3‐05–03: Therapeutic effects of passive immunization with an Aβ‐oligomer‐ specific antibody in APP transgenic mice
Author(s) -
Ebert Ulrich,
Auwera Ingrid,
Nolte Marc,
Meyer Axel,
Müller Reinhold,
Mueller Bernhard K.,
Labkovsky Boris,
Leuven Fred,
Gross Gerhard,
Schoemaker Hans,
Sullivan James P.,
Hillen Heinz
Publication year - 2008
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.2008.05.443
Subject(s) - oligomer , immunization , antibody , genetically modified mouse , monoclonal antibody , monomer , transgene , chemistry , medicine , immunology , microbiology and biotechnology , biochemistry , biology , organic chemistry , gene , polymer
pounds that can prevent amyloid oligomer/fibril formation. The targeted amyloids include amyloid-beta of Alzheimer’s, prion, alpha-synuclein of Parkinson’s, transthyretin, insulin, and Ig light chains. Screening techniques for assessing the effectiveness of small molecule inhibitors include a variety of physical-chemical and toxicity assays (e.g., turbidity and Congo red or thioflavin binding), morphological imaging (EM; AFM), spectroscopy (CD; NMR), and cytotoxicity and biochemistry (cell cultures; protease-resistance; immunoblotting). Methods: X-ray fiber diffraction from amyloids shows that their two key structural features are the 4.7 Å-distance between H-bonded beta-strands and the side chain-dependent 5-15 Å-distance between beta-pleated sheets. The widths of these reflections are related reciprocally to the extent of H-bonding and intersheet stacking. Thus, by measuring the integral widths and integrated intensities of these signature reflections, we used -ray fiber diffraction to test the inhibitory effect of a number of small aromatic molecules and N-methylated Abeta16-22 on the aggregation of different Abeta analogues (sequences 1-40, 11-25, 12-28, 17-28, and 16-22). Results: X-ray diffraction assessment showed that Cat’s claw, tannic acid, and quinine were more effective than curcumin, morin, and melatonin in impeding amyloid fiber formation, based on the criterion of crystallite volume. As their concentration increased, tetracycline and cotinine decreased the coherent length of the 4.7 Å-reflection, and Cat’s claw abolished this reflection. For the N-methylated and control peptides, there were no substantial differences in spacings and coherent lengths; however, the relative volumes of the beta-crystallites, which was calculated from the magnitude of the intensities, decreased with increase in the concentration of the methylated peptide, which may be accounted for by the its binding to the monomer or preamyloid oligomer of the non-methylated peptide. Conclusions: Fiber diffraction can help specify in an in vitro screen whether an amyloidophilic compound inhibits fibril formation, and if so, whether by impeding H-bonding or by altering intersheet interactions. Developing and implementing a high-throughput screen should be straightforward using robotic sample preparation, sample movement through a high-intensity -ray beam, automated data collection with fast electronic detectors, and automated analysis of the -ray data.