Basic Science and Pathogenesis

Area of Science:

• Neuroscience
• Genomics
• Pathology

Background:

• Cerebral amyloid angiopathy (CAA), prevalent in Alzheimer's disease (AD), involves Aβ40 deposition and blood-brain barrier (BBB) leakage.
• CAA is linked to increased risk of stroke, hemorrhage, and cognitive decline.
• Cell-type-specific mechanisms driving CAA and BBB integrity remain unclear.

Purpose of the Study:

• To investigate cell type-specific gene expression and intercellular communication in Alzheimer's disease (AD) brains with varying cerebral amyloid angiopathy (CAA) severity.
• To identify molecular mechanisms underlying CAA pathology and blood-brain barrier (BBB) integrity.

Main Methods:

• Single-nucleus RNA sequencing (snRNAseq) of temporal cortex from 79 AD donors.
• Correlation analysis of gene expression with Aβ40 levels and tight junction proteins (claudin-5, occludin).
• Intercellular communication and gene regulatory network analyses.

Main Results:

• Identified 25 cell clusters, including neuronal, glial, and vascular types.
• Higher CAA and Aβ40 levels correlated with altered cell proportions (reduced neurons, increased glia/vasculature).
• Discovered glia-to-pericyte communication pathways and pericytic gene networks associated with CAA and BBB integrity.

Conclusions:

• Glia-to-pericyte interactions and pericytic gene networks are implicated in CAA and BBB dysfunction in AD.
• Identified potential therapeutic targets within these regulatory networks.
• Further validation using external datasets and functional studies is warranted.