Sometimes inflammation can help the brain

To test the role of STING, the researchers conducted a series of experiments on mice. Some animals had this gene turned off, while others were left to work as usual. The results were surprising: in mice without STING, memory deteriorated faster, movements became less confident, and signs of senile weakness appeared much earlier. Their condition was similar to what happens with dementia in humans.

The main secret turned out to be in the work of brain cells called microglia. They are usually responsible for cleaning damaged neurons, clearing the brain of protein accumulations and supporting the work of other cells. But without STING, these cells became less effective. The brain was gradually overgrown with debris, which accelerated the aging process.

An equally important discovery concerned the blood-brain barrier, a protective system that separates the brain from toxins and microbes, but allows oxygen and nutrients to pass through. In animals without STING, the barrier became leaky, microbleeds appeared in the brain, and this directly affected coordination and movements.

Scientists note that such results change the approach to future drugs for Alzheimer’s disease. Previously, it was believed that blocking STING meant slowing down inflammation and protecting the brain. In fact, disabling this molecule can have the opposite effect and accelerate the destruction of the nervous system.

Of particular interest is the fact that about 40% of people are born with variants of the STING gene that make it less active. This means that millions of people around the world are already living with reduced brain protection, and it is especially important for them to understand which mechanisms compensate for this loss and whether they can be stimulated.

The authors of the study plan to continue their work and find out which other immune pathways are activated if STING does not work. Perhaps they will suggest new directions for therapy or even open the way to gene correction.