Antibodies Raised Against an Aβ Oligomer Mimic Recognize Pathological Features in Alzheimer’s Disease and Associated Amyloid-Disease Brain Tissue

Abstract

Antibodies that target the β-amyloid peptide (Aβ) and its associated assemblies are important tools in Alzheimer's disease research and have emerged as promising Alzheimer's disease therapies. This paper reports the creation and characterization of a triangular Aβ trimer mimic composed of Aβ17–36 β-hairpins, and the generation and study of polyclonal antibodies raised against the Aβ trimer mimic. The Aβ trimer mimic is covalently stabilized by three disulfide bonds at the corners of the triangular trimer to create a homogeneous oligomer. Structural, biophysical, and cell-based studies demonstrate that the Aβ trimer mimic shares characteristics with oligomers of full-length Aβ: X-ray crystallography elucidates the high-resolution structure of the trimer and reveals that four copies of the trimer assemble to form a dodecamer; SDS-PAGE, size exclusion chromatography, and dynamic light scattering reveal that the trimer also forms higher-order assemblies in solution; cell-based toxicity assays show that the trimer elicits LDH release, decreases ATP levels, and activates caspase-3/7 mediated apoptosis. Immunostaining studies on brain slices from people who lived with Alzheimer's disease as well as people who lived with Down syndrome reveal that the polyclonal antibodies raised against the Aβ trimer mimic recognize pathological features including different types of Aβ plaques and cerebral amyloid angiopathy. These findings suggest that the triangular trimer structural motif is important in Alzheimer's disease and may thus constitute a new structurally defined molecular target for diagnostic and therapy development.

Generation and study of antibodies against two triangular trimers derived from Aβ

“…RBKLT_20, RBKLT_16, reported the generation and study of polyclonal antibodies raised against an analogue of 2AT that contains the Aβ 24-29 loops. [33] Unlike the 2AT and KLT mAbs reported in the current article, these polyclonal antibodies strongly recognize pathological Aβ in brain slices from individuals who lived with Alzheimer's disease as well as brain slices from 5xFAD mice. These findings taken together with the findings in this article, suggest that the β-hairpin loop may be an important structure for generating antibodies against Aβ oligomer mimics that bind biogenic Aβ assemblies.…”

A β-barrel-like tetramer formed by a β-hairpin derived from Aβ

“…1,2 Synthetic trimers of peptides derived from Ab have been used to raise antibodies that recognize pathological features in tissues isolated from Alzheimer's brains. 3 Tetramers and octamers of Ab have demonstrated pore-forming activity against lipid-bilayers. 4 Photo-induced crosslinking studies of Ab 42 have revealed the formation of pentamers and hexamers, while ion mobility-mass spectrometry studies have shown that Ab 42 forms b-barrel shaped hexamers in the presence of membrane mimetic micelles.…”