From Cold Sores to Memory Loss: The Herpes-Alzheimer’s Connection Unveiled

A new study has uncovered a surprising link between Alzheimer’s disease and Herpes Simplex Virus-1 (HSV-1).

Researchers found HSV-1 proteins embedded in Alzheimer’s brains, revealing how the virus is inhibited by tau protein — a key player in the disease. These insights could pave the way for innovative treatments targeting viral activity and the brain’s immune response to slow or even stop Alzheimer’s progression.

Intriguing Link Between Herpes Virus and Alzheimer’s

A groundbreaking study led by Dr. Or Shemesh from the School of Pharmacy at the Hebrew University of Jerusalem has revealed a surprising link between Alzheimer’s disease and the Herpes Simplex Virus-1 (HSV-1). Using advanced techniques, researchers identified 19 HSV-1-related proteins in the brains of individuals with Alzheimer’s at various stages of the disease. This discovery adds to the growing evidence that infections like HSV-1 could influence the development and progression of Alzheimer’s.

One notable finding was the increased activity of a herpesvirus protein called ICP27, which became more prominent as Alzheimer’s progressed. The study found that ICP27 occupied the same regions of the brain as tau, a protein known to become toxic in Alzheimer’s disease. Interestingly, ICP27 was not associated with amyloid plaques, another major feature of the illness. These findings suggest that HSV-1 might directly interact with tau, potentially driving the harmful changes linked to Alzheimer’s.

Insights from Human Brain Organoids

The team’s experiments with human brain organoids derived from stem cells revealed that HSV-1 infection can increase tau modifications at specific sites linked to Alzheimer’s disease. Remarkably, these modifications seem to help protect brain cells early on by reducing the amount of virus and preventing cell death. However, as the disease progresses, these same processes may contribute to the brain damage associated with Alzheimer’s. The study also highlighted the role of Alzheimer’s pathologies as part of the brain’s natural immune system in this process, focusing on a pathway called cGAS-STING, which influences tau changes.

Dr. Shemesh explained, “Our research shows how HSV-1 interacts with the brain and influences the pathologies of Alzheimer’s disease. Early on, the changes in tau may protect brain cells by limiting the virus, but as the disease advances, these same changes could lead to more harm and accelerate neurodegeneration.”

Potential Therapeutic Implications

This study provides new insights into how infections and the brain’s immune response may be involved in Alzheimer’s disease. It suggests that targeting viral activity or modifying the immune system’s response could offer new treatment possibilities. While more research is needed to fully understand these processes, these findings open the door to innovative ways to slow or stop the progression of this devastating disease.

For more on this research, see How a Common Virus Could Trigger Alzheimer’s Disease.

Reference: “Anti-herpetic tau preserves neurons via the cGAS-STING-TBK1 pathway in Alzheimer’s disease” by Vanesa R. Hyde, Chaoming Zhou, Juan R. Fernandez, Krishnashis Chatterjee, Pururav Ramakrishna, Amanda Lin, Gregory W. Fisher, Orhan Tunç Çeliker, Jill Caldwell, Omer Bender, Peter Joseph Sauer, Jose Lugo-Martinez, Daniel Z. Bar, Leonardo D’Aiuto and Or A. Shemesh, 2 January 2025, Cell Reports.