Is Alzheimer's disease linked to Herpes simplex virus type 1 infection? A mini-review of the molecular correlation and the possible disease connections

Abstract

Alzheimer's disease (AD) is the most common neurodegenerative disease in the world. Several pathological pathways and genetic alterations have been linked to AD; however, the definitive cause of the disease remains unknown. Recently, an increasing body of evidence suggests that neurodegenerative diseases, including AD, might be triggered by microbial infections. Herpes simplex virus type 1 (HSV1) has been found in brain samples from dead AD patients. At some point of in their lifetime, every person comes into contact with HSV1, but when this enters the brain, it remains latent. However, it was observed that when a person becomes old, and there is a decline in their immunity, the latent HSV1 virus becomes reactivated. The reactivated virus then causes damage to the neural cell DNA and disrupts the DNA repair system, leading to AD. The present review would provide a clear understanding of how HSV1 influences DNA damage, and causes plaque formation and phosphorylation of tau protein, which in turn leads to AD, by inducing the production of interferons that would facilitate the production of specific humoral immunity, which could lead to neurodegeneration.