Cross-Seeding Interaction between β-Amyloid and Human Islet Amyloid Polypeptide

Area of Science:

• Biochemistry
• Molecular Biology
• Neuroscience

Background:

• Alzheimer's disease (AD) and type 2 diabetes (T2D) are protein misfolding diseases.
• Cross-sequence interactions between β-amyloid peptide (Aβ) in AD and human islet amyloid polypeptide (hIAPP) in T2D suggest a link.
• Mechanisms of Aβ and hIAPP interaction and their role in amyloidogenesis are not fully understood.

Purpose of the Study:

• Investigate the impact of cross-sequence interactions between Aβ and hIAPP on hybrid amyloid structures.
• Analyze conformational changes and aggregation kinetics influenced by Aβ-hIAPP interactions.
• Elucidate the molecular basis of cross-seeding between AD and T2D peptides.

Main Methods:

• Combined experimental and simulation approaches.
• Analysis of hybrid amyloid fibril formation and structure.
• Molecular dynamics simulations to study oligomer association and conformational changes.

Main Results:

• Aβ and hIAPP form hybrid amyloid fibrils with β-sheet-rich structures.
• Cross-seeding alters aggregation kinetics, retarding nucleation and accelerating fibrillization.
• Conformational transition from random coil to α-helix to β-sheet observed.
• Molecular dynamics revealed efficient cross-seeding via compatible U-shaped β-sheet structures in oligomers.

Conclusions:

• Conformational compatibility between Aβ and hIAPP aggregates is crucial for cross-seeding.
• Cross-seeding mechanisms may offer insights into the molecular interplay between Alzheimer's disease and type 2 diabetes.
• Understanding these interactions could inform therapeutic strategies for both diseases.