Inhibition of Nwd1 activity attenuates neuronal hyperexcitability and GluN2B phosphorylation in the hippocampus

Background: NACHT and WD repeat domain-containing protein 1 (Nwd1) is a member of the innate immune protein subfamily. Nwd1 contributes to the androgen receptor signaling pathway and is involved in axonal growth. However, the mechanisms that underlie pathophysiological dysfunction in seizures remain unclear.

Methods: Biochemical methods were used to assess Nwd1 expression and localization in a mouse model of kainic acid (KA)-induced acute seizures and temporal lobe epilepsy (TLE) patients. Electrophysiological recordings were used to measure the role of Nwd1 in regulating synaptic transmission and neuronal hyperexcitability in a model of magnesium-free-induced seizure in vitro. Behavioral experiments were performed, and seizure-induced pathological changes were evaluated in a KA-induced seizure model in vivo. GluN2B expression was measured and its correlation with Tyr1472-GluN2B phosphorylation was analyzed in primary hippocampal neurons.

Findings: We demonstrated high protein levels of Nwd1 in brain tissues obtained from mice with acute seizures and TLE patients. Silencing Nwd1 in mice using an adeno-associated virus (AAV) profoundly suppressed neuronal hyperexcitability and the occurrence of acute seizures, which may have been caused by reducing GluN2B-containing NMDA receptor-dependent glutamatergic synaptic transmission. Moreover, the decreased activation of Nwd1 reduced GluN2B expression and the phosphorylation of the GluN2B subunit at Tyr1472.

Interpretation: Here, we report a previously unrecognized but important role of Nwd1 in seizure models in vitro and in vivo, i.e., modulating the phosphorylation of the GluN2B subunit at Tyr1472 and regulating neuronal hyperexcitability. Meanwhile, our findings may provide a therapeutic strategy for the treatment of epilepsy or other hyperexcitability-related neurological disorders. FUND: The funders have not participated in the study design, data collection, data analysis, interpretation, or writing of the report.