Dissecting the phenotypes of Dravet syndrome by gene deletion

Moran Rubinstein, Sung Han, Chao Tai, Ruth E. Westenbroek, Avery Hunker, Todd Scheuer, William A. Catterall*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Neurological and psychiatric syndromes often have multiple disease traits, yet it is unknown how such multi-faceted deficits arise from single mutations. Haploinsufficiency of the voltage-gated sodium channel Nav1.1 causes Dravet syndrome, an intractable childhood-onset epilepsy with hyperactivity, cognitive deficit, autistic-like behaviours, and premature death. Deletion of Nav1.1 channels selectively impairs excitability of GABAergic interneurons. We studied mice having selective deletion of Nav1.1 in parvalbumin- or somatostatin-expressing interneurons. In brain slices, these deletions cause increased threshold for action potential generation, impaired action potential firing in trains, and reduced amplification of postsynaptic potentials in those interneurons. Selective deletion of Nav1.1 in parvalbumin- or somatostatin-expressing interneurons increases susceptibility to thermally-induced seizures, which are strikingly prolonged when Nav1.1 is deleted in both interneuron types. Mice with global haploinsufficiency of Nav1.1 display autistic-like behaviours, hyperactivity and cognitive impairment. Haploinsufficiency of Nav1.1 in parvalbumin-expressing interneurons causes autistic-like behaviours, but not hyperactivity, whereas haploinsufficiency in somatostatin-expressing interneurons causes hyperactivity without autistic-like behaviours. Heterozygous deletion in both interneuron types is required to impair long-term spatial memory in context-dependent fear conditioning, without affecting short-term spatial learning or memory. Thus, the multi-faceted phenotypes of Dravet syndrome can be genetically dissected, revealing synergy in causing epilepsy, premature death and deficits in long-term spatial memory, but interneuron-specific effects on hyperactivity and autistic-like behaviours. These results show that multiple disease traits can arise from similar functional deficits in specific interneuron types.

Original languageEnglish
Pages (from-to)2219-2233
Number of pages15
JournalBrain
Volume138
Issue number8
DOIs
StatePublished - 1 Aug 2015
Externally publishedYes

Funding

FundersFunder number
National Institute of Neurological Disorders and Stroke
National Institutes of HealthR01 NS25704
National Institute of Neurological Disorders and StrokeR01NS025704

    Keywords

    • Dravet syndrome
    • Na1.1
    • interneurons
    • parvalbumin
    • sodium channel
    • somatostatin

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