The health of the brain is often linked to neurons, but neurons are only one part of a much bigger picture.
A complex team of blood vessels and immune cells works constantly to protect the brain.
These cells form what is known as the blood-brain barrier — a tightly controlled wall that decides what can and cannot enter the brain. It also helps clean up waste and defend against dangerous invaders.
A new study from Gladstone Institutes and UC San Francisco reveals that many of the genetic risks for brain diseases like Alzheimer’s and stroke actually influence this guardian system of the brain, not just the neurons.
For years, scientists have found many changes in DNA that can increase the risk of diseases such as Alzheimer’s, Parkinson’s, and multiple sclerosis.
But most of these changes aren’t in the genes themselves — they’re in the nearby parts of DNA that control how genes are turned on or off.
These controlling regions are sometimes called “dimmer switches.” Until recently, researchers didn’t know which cell types these switches worked in, making it hard to understand how genetic risks actually lead to disease.
To solve this mystery, the research team created a new technique called MultiVINE-seq. This method allowed them to gently collect blood vessel and immune cells from donated human brain tissue.
For the first time, scientists could look at both the genes that were turned on and the settings of the switches in these guardian cells.
The team analyzed brain samples from 30 people, some with neurological diseases and some without. This gave them a full picture of how genes and switches behaved in each major brain cell type.
They discovered something surprising. Many of the risky DNA changes that are linked to brain diseases do not act in neurons. Instead, they act in the cells that form the blood-brain barrier — the protective shield of blood vessels and immune cells.
These cells are at the border between the brain and the body, and this location may be exactly why they are so important.
The team also found that different diseases affect this brain barrier in different ways. In stroke, the risky genes tend to weaken the structure of blood vessels. In Alzheimer’s, the genes make immune cells more active, leading to too much inflammation.
In particular, they found one DNA variant that is linked to Alzheimer’s in a gene called PTK2B. This variant makes T cells — a type of immune cell — more likely to become active and enter the brain. These active T cells were found around the sticky protein clumps known as amyloid plaques that are a hallmark of Alzheimer’s disease.
This discovery is important because PTK2B is already a target for cancer drugs, which means scientists might be able to repurpose these drugs to help people with Alzheimer’s.
Because these guardian cells are located at the boundary between the brain and the rest of the body, they are more exposed to diet, infections, stress, and other outside factors. This makes them easier to reach with drugs, and their condition can also be influenced by lifestyle choices.
In conclusion, this study shifts the focus from neurons to the brain’s border cells. It shows that many of the genetic risks for brain diseases act through these important blood vessel and immune cells. This opens the door to new treatments that aim to protect the brain by supporting its outer defenses.
If you care about stroke, please read research about Research finds a better high blood pressure treatment for stroke patients and findings of Scientists find a better drug than statins for stroke patients.
For more about stroke, please read studies about Half of people with heart rhythm diseases dying of heart attack, stroke and findings of New method reduces heart attacks and strokes over five years.
The study is published in Neuron.
Copyright © 2025 Knowridge Science Report. All rights reserved.
