The University of Pittsburgh researchers uncovered a surprising link between Alzheimer’s disease and herpes simplex virus-1 (HSV-1) which suggests that viral infections may play a role in the disease.
The study has been published in Cell Reports. It revealed how tau protein, often viewed as harmful in Alzheimer’s, might initially protect the brain from the virus but contribute to brain damage later.
“Our study challenges the conventional view of tau as solely harmful, showing that it may initially act as part of the brain’s immune defense,” said senior author Or Shemesh, PhD, assistant professor in the Department of Ophthalmology at Pitt.
These findings could lead to new treatments targeting infections and the brain’s immune response.
“These findings emphasize the complex interplay between infections, immune responses and neurodegeneration, offering a fresh perspective and potential new targets for therapeutic development,” added Shemesh.
The scientists identified forms of HSV-1-related proteins in Alzheimer’s brain samples, with greater amounts of viral proteins co-localized with tangles of phosphorylated tau. It is one of the hallmarks of Alzheimer’s disease pathology in the brain regions which are especially vulnerable to Alzheimer’s across disease stages.
Further studies on miniature models of human brains in a Petri dish suggested that HSV-1 infection could modulate levels of brain tau protein and regulate its function, a protective mechanism that seemed to decrease post-infection death of human neurons.
While the precise mechanisms by which HSV-1 influences tau protein and contributes to Alzheimer’s disease are still unknown, Shemesh and his colleagues plan to explore those questions in future research.