Huntington disease is a rare inherited brain disorder that destroys nerve cells and leads to progressive movement, cognitive, and psychiatric symptoms. Researchers from Florida Atlantic University and collaborators announced on June 8 that they have identified a key immune pathway that may drive damaging inflammation in the disease, suggesting a new direction for future therapies.
The study, published in the Proceedings of the National Academy of Sciences, found that blocking the cGAS-STING molecular pathway significantly reduced brain inflammation, protected neurons, and improved movement in a humanized mouse model of Huntington disease. The cGAS-STING pathway is part of the body's immune defense system responsible for detecting abnormal DNA inside cells and triggering inflammation. While this response helps fight infections, excessive activation can cause chronic inflammation and cellular damage.
Previous research had shown high levels of cGAS activity in Huntington disease brains but did not clarify its role in progression. In this study, researchers genetically removed cGAS from mice with Huntington disease mutations. These mice showed improvements in motor coordination and balance tests as well as less body-weight loss over time. Examination of their brain tissue revealed lower levels of inflammation and greater preservation of neurons compared to controls.
Further analysis indicated healthier gene activity patterns linked to brain signaling and increases in protective bioactive lipids associated with regulating inflammation. In another phase of the study, scientists tested H-151—a drug inhibiting STING—and observed similar benefits including improved motor performance and reduced inflammatory activity.
"Current Huntington disease therapies largely focus on lowering huntingtin protein levels, but many of these approaches are complex, expensive, and difficult to scale because they also risk reducing the healthy version of the protein needed for normal brain function," said Srinivasa Subramaniam, Ph.D., senior author at Florida Atlantic University. "Our findings point to a potentially simpler and more accessible strategy: targeting the cGAS-STING inflammatory pathway with small-molecule drugs." Anuradha Kesharwani, Ph.D., postdoctoral associate at FAU's Subramaniam lab, said, "Small-molecule drugs targeting the cGAS-STING pathway could offer a more scalable and accessible therapeutic strategy for Huntington disease and potentially other neurodegenerative disorders as well."
Researchers believe chronic DNA damage may overstimulate this immune pathway in Huntington disease patients. They note it has also been implicated in other neurodegenerative disorders such as Alzheimer's disease, Parkinson's disease, and ALS.
While further studies are needed before clinical use can be considered, researchers say new oral inhibitors already under development could help translate these findings into future treatments aimed at slowing rather than just managing symptoms.
