Navβ2 knockdown improves cognition in APP/PS1 mice by partially inhibiting seizures and APP amyloid processing

Voltage-gated sodium channels beta 2 (Nav beta 2, encoded by SCN2B) is a substrate of beta-site amyloid precursor protein cleaving enzyme 1 (BACE1) and regulates cell surface expression of channels in neurons. Previous studies reported enhanced Nav beta 2 processing by BACE1 in Alzheimer's disease (AD) model and patients. We investigated whether changes in Nav beta 2 expression affect neuronal seizure and amyloid precursor protein (APP) processing in an AD mouse model. Our study used eight-month-old APP/presenilin 1 (PS1) mice and transgenic Nav beta 2 knockdown [by 61% vs. wild type (WT)] APP/PS1 mice (APP/PS1/Nav beta 2-kd), with age-matched WT and Nav beta 2 knockdown (Nav beta 2-kd) mice as controls. We found that Nav beta 2 knockdown in APP/PS1 mice partially reversed the abnormal Nav beta 2 cleavage and the changes in intracellular and total Nav1.1 alpha expression. It also restored sodium currents density in hippocampal neurons and neuronal activity, as indicated by EEG tracing; improved Morris water maze performance; and shifted APP amyloidogenic metabolism towards non-amyloidogenic processing. There were no differences in these indicators between WT and Nav beta 2-kd mice. These results suggest Nav beta 2 knockdown may be a promising strategy for treating AD.