Basic Science and Pathogenesis

Area of Science:

• Neuroscience
• Genetics
• Pathology

Background:

• Alzheimer's Disease (AD) neurodegeneration critically impacts CA1 neurons.
• Understanding cell-type specific vulnerability in CA1 is crucial for targeted AD therapies.
• The 5xFAD mouse model exhibits significant CA1 degeneration by 4-6 months of age.

Purpose of the Study:

• To identify specific CA1 cell types susceptible to AD neurodegeneration.
• To utilize cell-type specific gene markers for quantifying CA1 cell populations.
• To determine CA1 cell type susceptibility across different disease timepoints in the 5xFAD model.

Main Methods:

• Employed RNAscope single molecule fluorescent in situ hybridization (smFISH) to quantify RNA transcript levels in CA1 cell types.
• Utilized 5xFAD and wildtype (WT) mice at 6, 12, and 14 months of age.
• Performed cell segmentation and analysis using QuPath and SCAMPR software on high-resolution confocal microscopy images.

Main Results:

• Generated robust datasets quantifying over 100,000 RNA transcripts across 1000+ CA1 cells.
• Identified significant changes in specific CA1 cell types in 5xFAD mice compared to WT controls at mid-to-late disease stages.
• Revealed both primarily susceptible and neuroprotective cell types within the CA1 region in the context of AD.

Conclusions:

• Discrete neurons within the CA1 are primarily susceptible to AD neurodegeneration in the 5xFAD mouse model.
• This study provides a foundation for understanding CA1 cell-type specific pathology in Alzheimer's Disease.
• Future research will focus on transcriptomic alterations in vulnerable CA1 neurons preceding cell death.