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 and Aβ and dissociation of these peptides to their soluble-oligomeric and insoluble-fibrillar forms. We have validated the levels of soluble and insoluble Aβ and Aβ 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 and Aβ are elevated in both mouse strains. (2) 5XFAD mice exhibit elevated soluble and insoluble Aβ in cortical and hippocampal tissues, soluble Aβ in the hippocampus, and insoluble Aβ n both cortical and hippocampal tissues (3) Ts65Dn mice exhibit elevated levels of Aβ 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 and Aβ levels. We provide a streamlined and accessible protocol for the assessment of soluble and insoluble Aβ and Aβ levels from mouse or human origins, enabling a higher accessibility for researchers in the field to generate reliable Aβ-related measurements.