A protocol for quantitative analysis of murine and human amyloid-β_1-40 and _1-42

Amyloid-β (Aβ), a hallmark of Alzheimer's disease (AD), has long been a focus of basic and translation research in AD. Quantification and dissociation of the Aβ fractions in their soluble and insoluble forms, is a key factor in numerous AD studies.

Here we provide a generalized sandwich-enzyme-linked-immuno-sorbent-assay (sELISA) protocol for quantification of human and murine Aβ_1-40 and Aβ_1-42 and dissociation of these peptides to their soluble-oligomeric and insoluble-fibrillar forms.

We have validated the levels of soluble and insoluble Aβ_1-40 and Aβ_1-42 in the 5XFAD AD and the Ts65Dn Down-Syndrome (DS) mouse models in both the cortex, hippocampus and blood as follows: (1) blood levels of Aβ_1-40 and Aβ_1-42 are elevated in both mouse strains. (2) 5XFAD mice exhibit elevated soluble and insoluble Aβ_1-40 in cortical and hippocampal tissues, soluble Aβ_1-42 in the hippocampus, and insoluble Aβ_1-42in both cortical and hippocampal tissues (3) Ts65Dn mice exhibit elevated levels of Aβ_1-40 in the cortex.

Several methodologies have been proposed for the high throughput measure of Aβ, including HPLC-mass-spectrometry, micro-immunoelectrodes, immunoprecipitation and ELISA. Although commercial sELISA kits are widely used, herein, we describe a more accessible and cost-effective in-house protocol enabling to measure either human or murine, soluble and insoluble Aβ_1-40 and Aβ_1-42 levels.

We provide a streamlined and accessible protocol for the assessment of soluble and insoluble Aβ_1-40 and Aβ_1-42 levels from mouse or human origins, enabling a higher accessibility for researchers in the field to generate reliable Aβ-related measurements.