Implications of peptide assemblies in amyloid diseases

Area of Science:

• Biochemistry
• Molecular Biology
• Cell Biology

Background:

• Neurodegenerative disorders and type 2 diabetes are global epidemics with significant social and economic impacts.
• Both diseases share characteristics like cross-β amyloid fibril formation and cell loss (neuronal or pancreatic β-cells).
• The underlying pathologies are complex and not fully understood.

Purpose of the Study:

• To review research on the self-assembly of amyloid proteins linked to Alzheimer's, Parkinson's, type 2 diabetes, and prion diseases.
• To discuss the toxicity mechanisms of these amyloid proteins, including interactions with cellular components and external agents.
• To highlight similarities and differences in amyloid protein structural transitions and their pathological consequences.

Main Methods:

• Review of scientific literature on amyloid protein self-assembly (amyloid-beta, alpha synuclein, human islet amyloid polypeptide, prions).
• Analysis of research on protein interactions with membranes, metal ions, small molecules, and nanoparticles.
• Examination of studies on protein structural transitions (monomer to alpha-helix to β-sheet) and oligomer formation.

Main Results:

• Amyloid proteins exhibit common self-assembly pathways, transitioning from monomers to alpha-helices and then β-sheets upon membrane interaction.
• Off-pathway oligomers are generally considered the toxic species, irrespective of protein sequence or properties, rather than mature amyloid fibrils.
• Molecular self-assembly plays a critical role in the biological and pathological effects of these proteins, including intercellular spreading.

Conclusions:

• Understanding the structure-function-toxicity relationship of amyloid proteins is key to developing diagnostics and therapeutics.
• Targeting off-pathway oligomers presents a promising strategy for mitigating amyloid-related diseases.
• Further research into the molecular self-assembly processes can unlock new avenues for disease intervention.