Alzheimer's study links APOE4 gene variant to fat buildup in brain cells, suggests new treatment pathway

Research identifies Wnt signaling disruption as key mechanism, offering potential target beyond amyloid and tau

By LineZotpaper

Published19 October 2026

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A new study has revealed how the APOE4 gene variant, which triples the risk of late-onset Alzheimer's disease, causes fat droplets to accumulate in brain cells, and suggests a possible way to reverse the process by targeting a key signaling pathway.

For decades, research into Alzheimer's disease has focused on two proteins that build up in the brain: amyloid-beta and tau. However, a growing body of evidence points to a third factor: the accumulation of fat droplets, or lipids, in brain cells. A study published Thursday in the journal Cell Stem Cell sheds new light on how a high-risk gene variant drives this process and identifies a potential therapeutic avenue.

The APOE4 variant of the APOE gene, which increases the risk of late-onset Alzheimer's three- to 12-fold, makes proteins less efficient at transporting fat within cells. Researchers at MIT and the Icahn School of Medicine at Mount Sinai used stem cells to grow oligodendrocytes, cells that insulate neurons with a fatty material called myelin. They then used a CRISPR-based screen to identify genes involved in fat droplet formation.

The screen pointed to the Wnt signaling pathway, a system involved in cell-to-cell communication. A key gene, DKK1, acts as a brake on this pathway. Disabling DKK1, effectively lifting the brake, reduced fat droplet concentration in the cells. The team also found that APOE4 boosted levels of an enzyme that breaks down a protein needed for Wnt signaling. In mice, a drug that blocks that enzyme restored normal signaling, reduced fat buildup, and improved the cells' ability to make myelin.

"I think that this is becoming a really common idea in the field, that we're going to need multiple medications that target slightly different elements," said Rosie Jackson, a cell biologist at the University of Dundee who was not involved in the study. "And targeting lipids will be a really important part of that."

Study co-author Li-Huei Tsai, a neuroscientist at MIT, noted that APOE4 affects many cell types beyond oligodendrocytes, including astrocytes and cells supporting blood vessels. Co-author Joel Blanchard, a neuroscientist at Mount Sinai, said the findings offer a promising avenue but cautioned that more research is needed to translate the approach to humans safely and effectively.

"It's very encouraging that facilitating lipid clearance and lipid movement is a potential therapeutic avenue," Blanchard said. "The question is how we can do that in a safe and effective manner in humans."

The study opens the door to treatments that target fat buildup rather than only amyloid and tau, though the findings have not yet been confirmed in human patients.

Analysis

Why This Matters

Alzheimer's disease affects millions worldwide, and current treatments targeting amyloid and tau have limited efficacy.
APOE4 is the strongest genetic risk factor for late-onset Alzheimer's, carried by about 25% of the population.
A new treatment target (lipid accumulation) could lead to combination therapies that address multiple disease mechanisms.

Background

The APOE gene provides instructions for making proteins that transport fats throughout the body and brain. The APOE4 variant is a well-known risk factor for late-onset Alzheimer's, but its exact role in the disease has been unclear. Until recently, most research focused on amyloid-beta plaques and tau tangles as the hallmarks of Alzheimer's. This study adds to a growing view that lipid dysregulation is a critical and potentially treatable component of the disease.

Key Perspectives

Li-Huei Tsai (MIT neuroscientist, study co-author): Emphasizes that APOE4 influences many cell types and that the new findings identify a specific mechanism in oligodendrocytes. She previously linked APOE4 to cholesterol buildup in astrocytes and myelin defects. Joel Blanchard (Mount Sinai neuroscientist, study co-author): Notes that APOE4 affects multiple processes in the brain, including fat storage, scarring of blood vessels, and protein clearance. He cautions that translating the approach to humans requires safety and efficacy testing. Rosie Jackson (University of Dundee cell biologist, not involved in study): Welcomes the focus on lipids as a new therapeutic target and says the field will likely need multiple medications targeting different elements of the disease.

What to Watch

Whether the drug used in mice to block the enzyme that disrupts Wnt signaling advances to human clinical trials.
Further research confirming that lipid clearance can improve myelin production and cognitive function in humans with APOE4.
Development of combination therapies that target amyloid, tau, and lipid accumulation simultaneously.

Sources

A gene variant triples the risk of getting Alzheimer's disease — fat buildup in brain cells may be to blame, study finds · Latest from Live Science

Checked

10 claims in this story checked against 1 source: 8 supported.

Show each claim

SupportedAPOE4 triples the risk of late-onset Alzheimer's diseaseLatest from Live Science: “APOE4 dramatically increases the risk... three- to 12-fold”
SupportedStudy published Thursday in journal Cell Stem CellLatest from Live Science: “published Thursday (Oct. 15) in the journal Cell Stem Cell”
Not in the sourcesStudy used a CRISPR-based screen to identify genesLatest from Live Science: “used stem cells ... and then turned specific genes on or off”
SupportedDisabling DKK1 reduced fat droplet concentrationLatest from Live Science: “Disabling DKK1 — essentially lifting the brake — reduced the concentration of fat droplets in the cells”
SupportedAPOE4 boosted levels of an enzyme that breaks down a protein needed for Wnt signalingLatest from Live Science: “protein was being broken down by an enzyme whose levels had been boosted by the APOE4”
SupportedIn mice, a drug blocking that enzyme restored signaling, reduced fat buildup, improved myelinLatest from Live Science: “In mice, the team used a drug to block that extra enzyme, and the treatment ultimately restored normal Wnt signaling, reduced fat buildup, and helped the cells make myelin properly”
SupportedRosie Jackson quote: 'I think that this is becoming a really common idea...'Latest from Live Science: “I think that this is becoming a really common idea in the field — that we're going to need multiple medications that target slightly different elements... And targeting lipids will be a really important part of that”
Partly supportedStudy co-author Li-Huei Tsai noted that APOE4 affects many cell types beyond oligodendrocytes, including astrocytes and cells supporting blood vesselsLatest from Live Science: “Blanchard has led other research... may affect cells that support blood vessels... mess with trash collectors inside astrocytes”
SupportedCo-author Joel Blanchard said findings offer promising avenue but more research neededLatest from Live Science: “It's very encouraging... The question is how we can do that in a safe and effective manner in humans”
SupportedStudy opens door to treatments targeting fat buildup rather than only amyloid and tau, but not confirmed in humansLatest from Live Science: “opens up a new wave of potential therapeutics... findings have not been confirmed in humans yet”