Pre-plaque conformational changes in Alzheimer's disease-linked Aβ and APP

Area of Science:

• Neuroscience
• Biochemistry
• Molecular Biology

Background:

• Alzheimer's disease (AD) is characterized by the accumulation of amyloid-beta (Aβ) peptides in the brain.
• Current therapeutic strategies primarily focus on reducing Aβ levels.
• Understanding the physiological conformation of Aβ is crucial for developing alternative therapeutic approaches, such as stabilizing its native state.

Purpose of the Study:

• To investigate the physiological conformations of Aβ and amyloid precursor protein (APP) in the brain.
• To determine if alterations in Aβ and APP conformations precede amyloid plaque formation.
• To identify novel therapeutic targets for Alzheimer's disease based on early conformational changes.

Main Methods:

• Synchrotron-based Fourier transform infrared micro-spectroscopy.
• Non-denaturing gel electrophoresis.
• Conformation-specific antibodies.

Main Results:

• The physiological conformations of Aβ and APP are altered in the brains of transgenic AD mouse models before the formation of amyloid plaques.
• Focal Aβ aggregates, preceding plaque formation, are localized to synaptic terminals.
• These early changes in Aβ and APP conformations suggest a potential role in AD pathogenesis.

Conclusions:

• The study reveals that alterations in Aβ and APP conformations occur early in the disease process, prior to plaque aggregation.
• Synaptic localization of early Aβ aggregates highlights the importance of synaptic dysfunction in AD.
• These pre-plaque conformational changes represent potential novel therapeutic targets for Alzheimer's disease.