Scn2a severe hypomorphic mutation decreases excitatory synaptic input and causes autism-associated behaviors.

Journal Article (Journal Article)

SCN2A, encoding the neuronal voltage-gated Na+ channel NaV1.2, is one of the most commonly affected loci linked to autism spectrum disorders (ASDs). Most ASD-associated mutations in SCN2A are loss-of-function mutations, but studies examining how such mutations affect neuronal function and whether Scn2a mutant mice display ASD endophenotypes have been inconsistent. We generated a protein truncation variant Scn2a mouse model (Scn2aΔ1898/+) by CRISPR that eliminates the NaV1.2 channel's distal intracellular C-terminal domain, and we analyzed the molecular and cellular consequences of this variant in a heterologous expression system, in neuronal culture, in brain slices, and in vivo. We also analyzed multiple behaviors in WT and Scn2aΔ1898/+ mice and correlated behaviors with clinical data obtained in human subjects with SCN2A variants. Expression of the NaV1.2 mutant in a heterologous expression system revealed decreased NaV1.2 channel function, and cultured pyramidal neurons isolated from Scn2aΔ1898/+ forebrain showed correspondingly reduced voltage-gated Na+ channel currents without compensation from other CNS voltage-gated Na+ channels. Na+ currents in inhibitory neurons were unaffected. Consistent with loss of voltage-gated Na+ channel currents, Scn2aΔ1898/+ pyramidal neurons displayed reduced excitability in forebrain neuronal culture and reduced excitatory synaptic input onto the pyramidal neurons in brain slices. Scn2aΔ1898/+ mice displayed several behavioral abnormalities, including abnormal social interactions that reflect behavior observed in humans with ASD and with harboring loss-of-function SCN2A variants. This model and its cellular electrophysiological characterizations provide a framework for tracing how a SCN2A loss-of-function variant leads to cellular defects that result in ASD-associated behaviors.

Full Text

Duke Authors

Cited Authors

  • Wang, H-G; Bavley, CC; Li, A; Jones, RM; Hackett, J; Bayleyen, Y; Lee, FS; Rajadhyaksha, AM; Pitt, GS

Published Date

  • August 9, 2021

Published In

Volume / Issue

  • 6 / 15

PubMed ID

  • 34156984

Pubmed Central ID

  • PMC8410058

Electronic International Standard Serial Number (EISSN)

  • 2379-3708

Digital Object Identifier (DOI)

  • 10.1172/jci.insight.150698

Language

  • eng

Conference Location

  • United States