Dynamics of the formation of a hydrogel by a pathogenic amyloid peptide: islet amyloid polypeptide

Sci Rep. 2016 Aug 18:6:32124. doi: 10.1038/srep32124.

Abstract

Many chronic degenerative diseases result from aggregation of misfolded polypeptides to form amyloids. Many amyloidogenic polypeptides are surfactants and their assembly can be catalysed by hydrophobic-hydrophilic interfaces (an air-water interface in-vitro or membranes in-vivo). We recently demonstrated the specificity of surface-induced amyloidogenesis but the mechanisms of amyloidogenesis and more specifically of adsorption at hydrophobic-hydrophilic interfaces remain poorly understood. Thus, it is critical to determine how amyloidogenic polypeptides behave at interfaces. Here we used surface tensiometry, rheology and electron microscopy to demonstrate the complex dynamics of gelation by full-length human islet amyloid polypeptide (involved in type II diabetes) both in the bulk solution and at hydrophobic-hydrophilic interfaces (air-water interface and phospholipids). We show that the hydrogel consists of a 3D supramolecular network of fibrils. We also assessed the role of solvation and dissected the evolution over time of the assembly processes. Amyloid gelation could have important pathological consequences for membrane integrity and cellular functions.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Amyloid beta-Peptides / chemistry*
  • Amyloid beta-Peptides / metabolism
  • Deuterium Oxide / chemistry
  • Hydrogels / chemistry*
  • Hydrophobic and Hydrophilic Interactions
  • Islet Amyloid Polypeptide / chemistry*
  • Islet Amyloid Polypeptide / metabolism
  • Liposomes / chemistry
  • Liposomes / metabolism
  • Microscopy, Electron
  • Rheology
  • Surface Tension
  • Water / chemistry

Substances

  • Amyloid beta-Peptides
  • Hydrogels
  • Islet Amyloid Polypeptide
  • Liposomes
  • Water
  • Deuterium Oxide