Inhibition of the GSK3β/Nav1.6 complex suppresses early-stage Alzheimer's hyperexcitability.

INTRODUCTION

Network hyperexcitability (NH) is observed in patients with early-stage Alzheimer's disease (AD), emerging decades before cognitive decline. A key molecular determinant of NH is voltage-gated Na+ channel 1.6 (Nav1.6), which mediates action potential firing in CA1 hippocampal neurons. Ameliorating NH through inhibition of the glycogen-synthase kinase 3β (GSK3β/Nav1.6 complex may provide immediate benefits to cognition and memory and slow AD progression.

METHODS

Hight-throughput virtual screening and multiple in vitro biological assays were utilized to identify compound 1063. Patch-clamp electrophysiology and electroencephalogram recordings were utilized to functionally assess 1063 in models of AD neuropathology.

RESULTS

Building on previous studies identifying GSK3β as a modulatory protein binding to the Nav1.6 C-terminal domain (CTD), we identified 1063, a brain-penetrant small molecule that inhibits GSK3β/Nav1.6 complex assembly and reduces NH in AD rodent models.

DISCUSSION: These results demonstrate the potential of the GSK3β/Nav1.6 complex as a therapeutic target for NH in early-stage AD.

HIGHLIGHTS: The glycogen synthase kinase 3-β (GSK3β)/Nav1.6 complex is a potential target for hyperexcitability in early Alzheimer's disease (AD). Compound 1063 dose-dependently decreases GSK3β/Nav1.6 complex assembly. Compound 1063 is functionally specific for Nav1.6 over other central nervous system (CNS) Nav isoforms. Ex vivo functional studies provide evidence for target engagement. 1063 dose-dependently reduces epileptiform activity in AD rodent model.