A stuck protein keeps Alzheimer inflammation running
In Alzheimer’s disease, the brain’s immune system stays permanently switched on. Researchers at Scripps Research have now identified the protein responsible and, for the first time, explained exactly why it gets stuck in the active position.
Chronic brain inflammation is a defining feature of Alzheimer’s disease. The brain’s immune cells, which normally detect and clear damage, become persistently activated. That sustained activation gradually damages the connections between nerve cells, worsening cognitive decline.
The protein at the centre of this process is called STING, which stands for Stimulator of Interferon Genes. Under normal conditions, STING activates temporarily in response to a threat, then switches off. In Alzheimer’s disease, STING undergoes a specific chemical modification that keeps it permanently active. The researchers at Scripps Research identified precisely which chemical change causes this lock-in.
What STING normally does
STING is part of the innate immune system, the body’s fast, non-specific defence response. It detects DNA that has leaked outside the cell nucleus, a signal associated with cell damage or infection. Once activated, STING triggers an inflammatory response. Normally, this response is temporary and self-limiting.
In Alzheimer’s, that self-limiting mechanism fails. The chemical modification alters the molecular structure of STING in a way that prevents the immune system from returning to baseline. The result is a continuous inflammatory state that damages synaptic connections between neurons.
A concrete target for new drugs
The discovery offers a specific molecular target for therapeutic development. If the chemical modification of STING can be blocked or reversed, it may be possible to reduce chronic inflammation in Alzheimer’s patients. That would not cure the disease, but it could slow one of its most damaging processes. Clinical applications remain distant, but the mechanism is now well-defined enough to warrant serious drug development efforts.