Scientists Identify STING Switch Driving Inflammation in Alzheimer’s Disease

Scientists have identified a molecular switch that drives chronic inflammation in Alzheimer’s disease, offering a potential new target for therapeutic intervention. The discovery centers on a specific chemical modification of the STING protein, which normally functions as part of the brain’s immune surveillance system but becomes pathologically overactive in Alzheimer’s.

Researchers at Scripps Research found that aging, toxins, and protein clumps such as amyloid-beta trigger a process called S-nitrosylation, where nitric oxide binds to the STING protein. This modification, specifically at the cysteine 148 amino acid building block, causes STING to cluster into inflammatory complexes that lead to sustained neuroinflammation and synapse loss.

The STING protein typically acts as an early-warning system for infections, but in Alzheimer’s brains, this protective mechanism becomes dysregulated. By modifying STING through S-nitrosylation at cysteine 148, the protein shifts from its normal immune surveillance role to driving the chronic inflammatory state that damages neural connections essential for memory, and learning.

In preclinical studies using human Alzheimer’s brain cells and mouse models, scientists demonstrated that blocking this specific S-nitrosylation modification at cysteine 148 effectively reduced inflammation. Importantly, this targeted approach did not compromise the body’s overall ability to fight infections, distinguishing it from broader immunosuppressive strategies.

Beyond reducing inflammation, preventing the S-nitrosylation of STING showed additional benefits in preclinical models. The intervention actively protected synapses — the junctions between nerve cells that are critical for cognitive function — from the degeneration typically seen in Alzheimer’s disease. This dual effect on both inflammation and synaptic preservation addresses two core pathological features of the condition.

The research highlights the potential of precision targeting in neuroinflammatory diseases. Rather than suppressing the entire immune response, focusing on the specific pathological modification of STING at cysteine 148 may allow for therapeutic intervention that preserves beneficial immune functions while mitigating harmful inflammation in the brain.

While the findings are based on preclinical models, they provide a clear mechanistic link between molecular aging processes, immune dysregulation, and neurodegeneration in Alzheimer’s disease. The identification of this specific druggable site on STING opens avenues for further investigation into disease-modifying treatments that could potentially slow or prevent cognitive decline by addressing the root inflammatory processes.