Epigenetic Shifts Reveal Alzheimer's Origins after Sustained Picomolar Aβ Exposure
Recent advances in sequencing have identified genetic risk factors for Alzheimer's disease (AD), but the molecular mechanisms triggering disease onset remain unclear. While high brain levels of amyloid-beta (A{beta}) impair synaptic function and memory, exposure to low picomolar (pM) A{beta} ; concentrations - typical of healthy brains - enhances these functions, while sustained exposure results in impairment. To investigate this transition from physiological to pathological A{beta} ; activity, we profiled DNA methylation and gene expression in C57B16 mice subjected to prolonged pM A{beta}42 exposure. We identified differentially methylated and expressed genes, including those involved in synaptic function, associated with three phases: memory enhancement (brief exposure), a transitional state with intact memory (intermediate), and memory decline (prolonged). These gene sets may represent early molecular drivers of AD pathogenesis.