Non-Fibrillar Oligomeric Amyloid-β within Synapses

Area of Science:

• Neuroscience
• Biochemistry
• Pathology

Background:

• Alzheimer's disease (AD) involves cognitive decline, neurodegeneration, and hallmark amyloid-beta (Aβ) plaques and tau tangles.
• Synaptic loss and dysfunction are key drivers of cognitive impairment in AD.
• The precise location and toxic forms of Aβ within synapses remain unclear.

Purpose of the Study:

• To determine the sub-synaptic localization of amyloid-beta (Aβ) oligomers.
• To identify which specific Aβ oligomeric species are synaptotoxic.
• To evaluate array tomography for high-throughput screening of Aβ antibodies.

Main Methods:

• Utilized stochastic optical reconstruction microscopy (STORM), immunogold electron microscopy, and Förster resonance energy transfer (FRET).
• Employed a plaque-bearing mouse model of Alzheimer's disease (AD).
• Applied array tomography to test a panel of Aβ antibodies for synaptic Aβ species identification.

Main Results:

• Oligomeric Aβ was consistently observed inside synaptic terminals across all imaging techniques.
• Different oligomeric Aβ species were identified within synapses.
• Array tomography proved effective for rapid assessment of Aβ antibody efficacy against specific aggregation states.

Conclusions:

• Oligomeric Aβ is present within synaptic terminals, suggesting a direct role in synaptic dysfunction in Alzheimer's disease (AD).
• The study identifies potential targets for therapeutic intervention against synaptotoxic Aβ species.
• Array tomography offers a valuable tool for developing and testing targeted Aβ antibody therapies for AD.