Alzheimer's Genome Rewiring
Researchers Map How 3D Genome Architecture Changes in Alzheimer's Brains
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Key Points
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Hicformer is described by Xinyue Lu as a computational test bed for exploring how altered genome folding may change gene activity.
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Midrange- and long-range genomic contacts increase while contacts between genes and nearby enhancer elements weaken across multiple brain cell types, indicating a widespread regulatory rewiring in Alzheimer\'s disease.
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In aging brains, embryonically derived microglia decline and are replaced by blood-derived immune-like microglia with inflammatory signatures, with a notable decline in cell populations important for maintaining the blood-brain barrier.
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Alzheimer\'s 3D genome mapping used postmortem prefrontal cortex tissue from individuals with and without Alzheimer\'s who participated in a long-term dementia study and donated their brains after death.
Scientists have found that Alzheimer's disease reshapes the 3D structure of DNA inside brain cells, disrupting how genes are switched on and off. Researchers from Carnegie Mellon University, the University of Pittsburgh, and the University of Washington mapped these changes using single-cell technology and a new deep learning model called Hicformer, according to Medical Xpress.
The findings suggest Alzheimer's is not just about amyloid plaques and tau tangles. It also involves a large-scale rewiring of how chromosomes fold inside neurons and other brain cells, potentially opening new doors for treatment targets, Genetic Engineering News reported.
How Chromosome Folding Goes Wrong in Alzheimer's
Inside every cell, DNA is tightly coiled and folded into a 3D shape. That shape controls which genes are active. In Alzheimer's brains, this folding breaks down in a specific way. Midrange and long-range contacts between DNA regions increase, while short contacts between genes and nearby "enhancer" elements weaken. Enhancers are stretches of DNA that help turn genes on. When those links weaken, gene activity goes wrong, according to Medical Xpress.
This regulatory breakdown happens across multiple brain cell types, not just one. Researchers call it a "compartment mingling" problem — boundaries that normally keep DNA regions separate start to blur. The result is widespread disruption to gene programs tied to synaptic function, meaning brain cells lose their ability to communicate properly, Genetic Engineering News reported.
Hicformer Predicts Gene Activity From DNA Structure
The team built a deep learning model called Hicformer to study these changes. It combines three inputs: DNA sequence, genome-folding patterns, and local 3D contacts. Together, these inputs let the model predict which genes are active in specific cell types. Researcher Xinyue Lu described Hicformer as "a computational test bed for exploring how altered genome folding may change gene activity," according to Newsy Today.
The team analyzed postmortem prefrontal cortex tissue — the brain region tied to memory and decision-making. Donors had participated in a long-term dementia study and agreed to donate their brains after death. The researchers compared tissue from people with Alzheimer's to tissue from people without it, using a method called GAGE-seq combined with spatial transcriptomics, which maps gene activity by location in tissue, Medical Xpress reported.
Microglia and the Immune System Join the Picture
The study also found major changes in microglia — the brain's immune cells. In aging brains, microglia that develop before birth decline in number. They are replaced by blood-derived immune cells with inflammatory signatures. At the same time, cell populations that help maintain the blood-brain barrier also decline, according to Head Topics.
These immune shifts compound the structural DNA changes. Inflammatory microglia behave differently than their predecessors, and their altered gene programs may worsen neurodegeneration. Related research shows age-related genome regulation changes begin in midlife, well before Alzheimer's symptoms appear, Head Topics noted.
A New Layer of Alzheimer's Biology With Therapeutic Promise
Researchers now frame Alzheimer's as a disease of chromatin reorganization — not just protein buildup. Chromatin is the packaged form of DNA inside cells. When its structure changes, the gene activity of entire cell types shifts. This multi-scale view connects chromosome folding to visible brain pathology for the first time at single-cell resolution, Genetic Engineering News reported.
That connection matters for therapy. If specific folding changes drive harmful gene programs, those changes could become drug targets. Scientists say the 3D genome is now a "fundamental regulatory layer" in neurodegeneration, sitting alongside amyloid and tau as a core part of the disease, according to Medical Xpress.
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