The contributions of unscheduled neuronal cell cycle events to the death of neurons in Alzheimer's disease.

Alzheimer's disease is a neurodegenerative disorder that accounts for the majority of the dementia in individuals over the age of 65. While much has been learned about the biology and biochemistry of the tau tangles and beta-amyloid plaques, less is known about the cell biology of the neuronal cell death process. This review examines one feature of this process, the unexpected occurrence of unscheduled cell cycle events in mature and normally non-mitotic neurons in the at-risk neuronal populations. The correlation of neuronal cell cycling and cell death is not unique to Alzheimer's, but the evidence in both human Alzheimer's disease and its mouse models suggests that these events are early disease related processes, that they are driving forces of the disease rather than indirect symptoms. Defining the biochemistry behind cell cycle initiation holds promise as a fresh therapeutic approach in the battle against this devastating disease.