N-methyl-D-aspartate receptor-mediated calcium influx connects amyloid-β oligomers to ectopic neuronal cell cycle reentry in Alzheimer's disease

Abstract

Introduction: Alzheimer's disease (AD) symptoms reflect synaptic dysfunction and neuron death. Amyloid-β oligomers (AβOs) induce excess calcium entry into neurons via N-methyl-D-aspartate receptors (NMDARs), contributing to synaptic dysfunction. The study described here tested the hypothesis that AβO-stimulated calcium entry also drives neuronal cell cycle reentry (CCR), a prelude to neuron death in AD.

Methods: Pharmacologic modulators of calcium entry and gene expression knockdown were used in cultured neurons and AD model mice.

Results: In cultured neurons, AβO-stimulated CCR was blocked by NMDAR antagonists, total calcium chelation with 1,2-Bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid tetrakis(acetoxymethyl ester) (BAPTA-AM), or knockdown of the NMDAR subunit, NR1. NMDAR antagonists also blocked the activation of calcium-calmodulin-dependent protein kinase II and treatment of Tg2576 AD model mice with the NMDAR antagonist, memantine, prevented CCR.

Discussion: This study demonstrates a role for AβO-stimulated calcium influx via NMDAR and CCR in AD and suggests the use of memantine as a disease-modifying therapy for presymptomatic AD.

Keywords: Alzheimer's disease; Amyloid-β oligomers; Calcium; NMDA receptor; Neuronal cell cycle reentry; Tau.