Herpes virus leads to Alzheimer's disease

ScienceDaily (Apr. 4, 2011) — Laboratories at the University of New Mexico (UNM), Brown University, and House Ear Institute (HEI) have developed a new technique to observe herpes simplex virus type 1 (HSV1) infections growing inside cells. HSV1, the cause of the common cold sore, persists in a latent form inside nerve cells. Re-activation and growth of HSV1 infections contribute to cognitive decline associated with Alzheimer's disease. Details are published in the March 31 issue of PLoS ONE. "Herpes infects mucous membranes, such as the lip or eye, and generates viral particles," submits study Principal Investigator Elaine Bearer, M.D., Ph.D., Harvey Family Professor and Vice Chair for Research, Department of Pathology, UNM School of Medicine. "These viral particles burst out of the cells of the mucous membrane and enter sensory nerve cells where they travel inside the nerve toward the brain. We now can see this cellular transportation system and watch how the newly formed virus engages cellular APP on its journey out of the cell." Tagging herpes virus inside cells with green fluorescent protein, scientists used live confocal imaging to watch HSV1 particles emerge from infected cells. Newly produced viral particles exit the cell nucleus and then bud into cellular membranes containing amyloid precursor protein (APP). Electron microscopy at HEI detailed the ultrastructural relationship between HSV1 particles and APP. This dance between viral particles and cellular APP results in changes in cellular architecture and the distribution of APP, the major component of senile plaques found in the brains of Alzheimer's disease patients. Results from this study indicate that most intracellular HSV1 particles undergo frequent, dynamic interplay with APP, which facilitates viral transport while interfering with normal APP transport and distribution. This dynamic interaction reveals a mechanism by which HSV1 infection leads to Alzheimer's disease. Read more>>