Finding ancestry-specific chromatin architecture in Alzheimer's disease

Area of Science:

• Genomics
• Epigenetics
• Neuroscience

Background:

• Genetic risk for Alzheimer's Disease (AD) differs significantly across diverse populations.
• Understanding the epigenetic mechanisms underlying ancestry-specific AD risk is crucial.

Purpose of the Study:

• To investigate if three-dimensional (3D) genome architecture variations contribute to ancestry-specific genetic risk for Alzheimer's Disease (AD).
• To explore novel epigenetic insights into population-specific AD risk factors.

Main Methods:

• Performed Hi-C analyses on frontal cortex tissue from individuals with African (AF) and European (EU) ancestry carrying the APOE ε4/ε4 genotype.
• Integrated single-nucleus ATAC-seq and RNA-seq data to correlate 3D genome structure with gene expression and chromatin accessibility.
• Utilized the DeepLoop pipeline for chromatin loop identification and HiC-QTL analysis.

Main Results:

• Identified significant ancestry-specific differences in 3D genome architecture at both compartment and chromatin loop levels.
• EU genomes exhibited more active compartments and larger, CTCF-enriched loops compared to AF genomes.
• Differentially expressed genes between AF and EU ancestries were significantly enriched at ancestry-specific loop loci (p<2.2×10^-16).

Conclusions:

• Variations in 3D genome structure exist between African and European ancestries.
• These structural genomic differences are associated with ancestry-specific gene expression patterns.
• The findings suggest that 3D genome architecture variations may play a role in the ancestry-specific genetic risk of Alzheimer's Disease.