Alzheimer's disease and brain development: common molecular pathways

Abstract

Research on the causes and treatments of Alzheimer's disease (AD) has led investigators down numerous avenues. Although many models have been proposed, no single model of AD satisfactorily accounts for all neuropathologic findings as well as the requirement of aging for disease onset. The mechanisms of disease progression are equally unclear. We hypothesize that alternative gene expression during AD plays a critical role in disease progression. Numerous developmentally regulated genes and cell cycle proteins have been shown to be re-expressed or activated during AD. These proteins include transcription factors, members of the cell cycle regulatory machinery, and programmed cell death genes. Such proteins play an important role during brain development and would likely exert powerful effects if re-expressed in the adult brain. We propose that the re-expression or activation of developmentally regulated genes define molecular mechanisms active both during brain development and in AD.

Figure 1

MAZi expression is increased in temporal cortex of Alzheimer's patients. Immunohistochemical staining of temporal cortex from A) control and B) Alzheimer's disease patients with the MAZi polyclonal antibody. The antibody was kindly provided by Dr. David J. Hall from Thomas Jefferson University, Philadelphia, PA. Magnification of both panels is 20×.

Figure 2

A model for the role of cell cycle proteins in Alzheimer's disease progression. See text for details.