Cryo-EM Analysis of the Effect of Seeding with Brain-derived Aβ Amyloid Fibrils

J Mol Biol. 2024 Feb 15;436(4):168422. doi: 10.1016/j.jmb.2023.168422. Epub 2023 Dec 28.

Abstract

Aβ amyloid fibrils from Alzheimer's brain tissue are polymorphic and structurally different from typical in vitro formed Aβ fibrils. Here, we show that brain-derived (ex vivo) fibril structures can be proliferated by seeding in vitro. The proliferation reaction is only efficient for one of the three abundant ex vivo Aβ fibril morphologies, which consists of two peptide stacks, while the inefficiently proliferated fibril morphologies contain four or six peptide stacks. In addition to the seeded fibril structures, we find that de novo nucleated fibril structures can emerge in seeded samples if the seeding reaction is continued over multiple generations. These data imply a competition between de novo nucleation and seed extension and suggest further that seeding favours the outgrowth of fibril morphologies that contain fewer peptide stacks.

Keywords: aggregation; amyloid beta; cryo-electron microscopy; prion; protein misfolding.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alzheimer Disease / metabolism
  • Alzheimer Disease / pathology
  • Amyloid beta-Peptides* / chemistry
  • Amyloid* / chemistry
  • Brain* / metabolism
  • Brain* / pathology
  • Cryoelectron Microscopy
  • Humans
  • Peptide Fragments* / chemistry

Substances

  • Amyloid
  • Amyloid beta-Peptides
  • Peptide Fragments
  • amyloid beta-protein (1-40)