Profiling NMDA receptor subcellular localization across different brain regions and disease stages in male and female 3xTg-AD mouse model

Alzheimer’s disease (AD) is a progressive neurodegenerative disorder characterized by synaptic dysfunction, memory loss, and cognitive decline. N-methyl-D-aspartate receptors (NMDARs) play a critical role in neuronal health, synaptic plasticity, and learning, with distinct functions at synaptic and extrasynaptic sites that respectively promote cell survival or trigger cell death pathways. Their mislocalization could underlie neuronal dysfunction in AD. The subcellular localization of NMDARs in AD remains poorly understood due to technical limitations. This study investigated the subcellular localization of GluN2A and GluN2B subunits using Airyscan super-resolution microscopy and 3D nearest-neighbor analysis in the CA1 region of the hippocampus and dorsal striatum of 3xTg-AD mice at two ages (2–3 and 9–12 months) and in both sexes. Our results revealed region-, age-, and sex-dependent NMDAR mislocalization. Compared to controls, early-stage 3xTg-AD mice exhibited greater synaptic GluN2B volume and less synaptic GluN2A localization. In contrast, aged female 3xTg-AD mice showed a higher synaptic GluN2A, whereas aged male 3xTg-AD mice showed increased mislocalization of GluN2A from synaptic to extrasynaptic sites, reflecting disrupted receptor anchoring and trafficking. The dorsal striatum remained relatively stable. These findings uncover changes in NMDAR localization during AD progression and provide insight into potential therapeutic strategies for neurodegenerative diseases.