Work

Pathogenesis of sporadic Alzheimer's disease by deficiency of NMDA receptor subunit GluN3A

Year: 2021

Type: article

Abstract: The Ca2+ hypothesis for Alzheimer's disease (AD) conceives Ca2+ dyshomeostasis as a common mechanism of AD; the cause of Ca2+ dysregulation, however, is obscure. Meanwhile, hyperactivities of N‐Methyl‐D‐aspartate receptors (NMDARs), the primary mediator of Ca2+ influx, are reported in AD. GluN3A (NR3A) is an NMDAR inhibitory subunit. We hypothesize that GluN3A is critical for sustained Ca2+ homeostasis and its deficiency is pathogenic for AD. Cellular, molecular, and functional changes were examined in adult/aging GluN3A knockout (KO) mice. The GluN3A KO mouse brain displayed age‐dependent moderate but persistent neuronal hyperactivity, elevated intracellular Ca2+, neuroinflammation, impaired synaptic integrity/plasticity, and neuronal loss. GluN3A KO mice developed olfactory dysfunction followed by psychological/cognitive deficits prior to amyloid‐β/tau pathology. Memantine at preclinical stage prevented/attenuated AD syndromes. AD patients’ brains show reduced GluN3A expression. We propose that chronic “degenerative excitotoxicity” leads to sporadic AD, while GluN3A represents a primary pathogenic factor, an early biomarker, and an amyloid‐independent therapeutic target.

Source: Alzheimer s & Dementia

DOI: 10.1002/alz.12398