In a significant breakthrough that pushes the boundaries of neurodegenerative research, a multi-institutional team of scientists has uncovered a previously underexplored feature of Alzheimer’s disease. The discovery, which sheds light on the complex physical organization of genetic material inside brain cells, could ultimately help researchers identify entirely new avenues for therapeutic intervention against a condition that currently affects millions of individuals worldwide.
The landmark study, published in the prestigious journal Science, reveals that the three-dimensional organization of the genome differs profoundly in certain brain cells taken from people with Alzheimer’s disease compared to healthy individuals. Researchers hailing from Carnegie Mellon University’s School of Computer Science, the University of Pittsburgh School of Medicine, and the University of Washington successfully connected these profound changes in genome folding directly with shifts in gene activity and the structural organization of brain tissue itself.
To build this remarkably detailed picture of molecular pathology, the collaborative team combined cutting-edge single-cell technology, advanced spatial mapping of brain tissue, and a newly engineered deep learning model. By fusing these diverse scientific methodologies, the researchers were able to view the diseased brain through an unprecedented lens, bridging the gap between microscopic genetic architecture and macroscopic tissue changes.
Looking Beyond Amyloid and Tau
For decades, the scientific community’s understanding of Alzheimer’s disease has been dominated by two primary biological hallmarks: the accumulation of amyloid-beta plaques and the formation of tau tangles. While these features remain central to the pathology of the disease, the new findings suggest that the medical field must look beyond these traditional markers to fully comprehend the complexity of the neurodegenerative process.
"Alzheimer’s disease cannot be understood one layer at a time," explained Jian Ma, the Ray and Stephanie Lane Professor of Computational Biology at Carnegie Mellon University, who led and supervised the ambitious study. "The genome’s 3D structure is a fundamental regulatory layer that helps to connect DNA sequence to gene activity. By integrating genome folding, cell state, and tissue context, we can move beyond cataloging disease-associated changes toward understanding how they fit together and which mechanisms to test next."
To understand the significance of this discovery, it helps to examine how genetic material is stored. DNA does not simply sit inside a human cell as a straightforward, linear strand. Instead, it folds into an intensely complex, highly organized three-dimensional structure. This physical arrangement plays a critical role in determining which specific genes are accessible and active at any given moment. Consequently, alterations in that physical organization can dramatically influence how cells function, survive, or degenerate.
To investigate these structural dynamics, the research team examined postmortem samples from the prefrontal cortex, a vital region situated at the front of the brain responsible for complex cognitive behavior, decision-making, and social interaction. The tissue samples were graciously provided by individuals with and without Alzheimer’s disease who had participated in long-term dementia studies and subsequently donated their brains for medical research to advance the scientific understanding of the condition.
A New Layer of Alzheimer’s Biology
To analyze these precious tissue samples, the investigators utilized GAGE-seq, an innovative laboratory technique capable of measuring both gene expression and three-dimensional genome contacts simultaneously within the exact same individual cell. These high-resolution molecular measurements were then meticulously combined with spatial transcriptomic maps, which preserve critical information about precisely where gene activity occurs within intact, undisturbed brain tissue.
By bringing these massive and complex datasets together, the researchers were able to directly connect the physical organization of the genome with gene regulation, while simultaneously observing where Alzheimer’s-related molecular and cellular changes manifested within the surrounding tissue architecture.
"Our study represents a major advance in understanding what goes wrong in Alzheimer’s disease," noted Hansruedi Mathys, assistant professor of neurobiology at the University of Pittsburgh’s Department of Neurobiology, who directed the Pitt arm of the collaborative study. "We know the classic hallmarks of Alzheimer’s disease — accumulation of amyloid-beta plaques and tau tangles — but our results establish higher-order chromatin alterations as a component of the molecular pathology associated with the disease, which currently affects seven million Americans, a number that continues to grow."
Amyloid-beta plaques and tau tangles have long stood at the forefront of Alzheimer’s research and drug development efforts. The new findings establish that changes in chromatin—the dense material made of DNA and associated proteins that packages the genome neatly inside cell nuclei—should now also be formally considered a core part of the disease’s intricate molecular landscape.
AI Connects Genome Folding to Gene Activity
A vital technological pillar of the research was the creation of Hicformer, a sophisticated artificial intelligence model specifically developed to investigate how genome structure may influence cellular behavior. The model was designed to ingest and analyze complex inputs, combining DNA sequence information with broad patterns of genome folding and detailed maps showing where different sections of DNA physically contact one another.
Using these multifaceted inputs, Hicformer is capable of predicting gene activity across a diverse array of cell types. Xinyue Lu, a doctoral student in Computational Biology who co-led the research, described the newly developed system as a powerful computational test bed. This digital environment can be freely utilized by researchers to explore how hypothetical or observed changes in genome folding might alter downstream gene activity.
"Measuring gene activity and genome folding in the same cell allows us to directly connect chromosome structure with disease-related gene programs," said Yang Zhang, a project scientist in the Computational Biology Department who also co-led the research. "Across several kinds of brain cells, this paired view revealed a consistent signature of 3D genome reorganization in Alzheimer’s disease and helped us prioritize regulatory regions for future mechanistic and therapeutic investigation."
DNA Organization Becomes Less Distinct
Through their rigorous data analysis, the researchers identified several consistent, striking differences in the genome architecture of cells derived from people who suffered from Alzheimer’s disease.
In a healthy cell, large sections of the genome are normally organized into relatively distinct active and inactive regions known as compartments. However, in the brain cells affected by Alzheimer’s disease, those vital boundaries appeared significantly less sharply defined. The research team aptly describes this pathological pattern as "increased compartment mingling."
Furthermore, several distinct kinds of brain cells exhibited fewer interactions between nearby sections of the genome, coupled with a notable increase in contacts between regions located much farther apart from one another. The data revealed that cells displaying a higher degree of compartment mingling also tended to exhibit lower overall levels of gene activity, signaling a generalized dampening of normal cellular functions.
The team also observed weaker interactions between specific genes and the nearby regulatory elements that normally act as switches to help control whether those genes are turned on or off. Concurrently, some contacts spanning intermediate distances grew stronger, painting a picture of widespread structural disorganization.
These profound structural differences were closely associated with reduced activity in biological programs essential for neurons and synapses, alongside notable disruptions in cellular metabolism and stress responses. Moreover, the researchers uncovered direct links to senescence-related programs operating within microglia—specialized immune cells residing in the central nervous system that play critical roles in maintaining brain health, clearing cellular debris, and responding to injury or infection.
Potential Clues for Future Alzheimer’s Treatments
When the investigators mapped these complex molecular changes across intact brain tissue, they discovered that the large-scale reorganization of the genome was connected not only to altered gene activity, but also to distinct differences in how various brain cells were physically arranged and distributed within the tissue microenvironment.
The results firmly establish three-dimensional genome organization as another critical layer of Alzheimer’s disease biology that can no longer be ignored. Beyond expanding fundamental scientific knowledge, the findings provide the academic and medical research communities with a robust conceptual framework for testing which specific changes in genome architecture might directly contribute to the onset and progression of the disease.
Looking ahead, future studies can now investigate whether particular structural modifications actively drive Alzheimer’s progression or whether any of the newly identified regulatory regions could eventually be harnessed as viable targets for entirely novel classes of therapeutics.
The research was supported by generous grants provided by the National Institutes of Health. Additional Carnegie Mellon University authors who contributed to the study include doctoral students Shahul Alam and Shike Wang, along with postdoctoral research associate Junjie Tang. Other University of Pittsburgh contributors include doctoral students Alexander K. Kunisky and Jude Baroudi, post-baccalaureate research fellows Sahar and Sahel Ghorbanikalateh, and visiting scholar Shihan Wang. The broad-based collaborative team also included researchers representing the Broad Institute of MIT and Harvard, the University of California, Los Angeles, the University of Washington, and the Rush Alzheimer’s Disease Center.