The interaction of insoluble Amyloid‐β with soluble Amyloid‐β dimers decreases Amyloid‐β plaque numbers
Author(s) -
Gerresheim Else F.,
Herring Arne,
Gremer Lothar,
MüllerSchiffmann Andreas,
Keyvani Kathy,
Korth Carsten
Publication year - 2021
Publication title -
neuropathology and applied neurobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.538
H-Index - 95
eISSN - 1365-2990
pISSN - 0305-1846
DOI - 10.1111/nan.12685
Subject(s) - thioflavin , in vivo , fibril , amyloid (mycology) , genetically modified mouse , in vitro , chemistry , neuropathology , biophysics , transgene , alzheimer's disease , senile plaques , amyloidosis , cognitive decline , protein aggregation , biochemistry , pathology , biology , medicine , disease , dementia , inorganic chemistry , microbiology and biotechnology , gene
Abstract Objectives The heterogeneity of Amyloid‐beta (Aβ) plaque load in patients with Alzheimer's disease (AD) has puzzled neuropathology. Since brain Aβ plaque load does not correlate with cognitive decline, neurotoxic soluble Aβ oligomers have been championed as disease‐causing agents in early AD. So far, investigating molecular interactions between soluble oligomeric Aβ and insoluble Aβ in vivo has been difficult because of the abundance of Aβ oligomer species and the kinetic equilibrium in which they coexist. Here, we investigated whether Aβ plaque heterogeneity relates to interactions of different Aβ conformers. Materials and Methods We took advantage of transgenic mice that generate exclusively Aβ dimers (tgDimer mice) but do not develop Aβ plaques or neuroinflammation during their lifetime, crossed them to the transgenic CRND8 mice that develop plaques after 90 days and measured Aβ plaque load using immunohistochemical and biochemical assays. Furthermore, we performed in vitro thioflavin T (ThT) aggregation assays titrating synthetic Aβ 42 ‐S8C dimers into fibril‐forming synthetic Aβ 42 . Results We observed a lower number of Aβ plaques in the brain of double transgenic mice compared to tgCRND8 mice alone while the average plaque size remained unaltered. Corroborating these in vivo findings, synthetic Aβ‐S8C dimers inhibited fibril formation of wild‐type Aβ also in vitro , seen by an increased half‐time in the ThT assay. Conclusions Our study indicates that Aβ dimers directly interfere with Aβ fibril formation in vivo and in vitro . The variable interaction of Aβ dimers with insoluble Aβ seeds could thus contribute to the heterogeneity of Aβ plaque load in AD patients.