PUBLICATION

NaV1.1 and NaV1.6 selective compounds reduce the behavior phenotype and epileptiform activity in a novel zebrafish model for Dravet Syndrome

Authors
Weuring, W.J., Singh, S., Volkers, L., Rook, M.B., van 't Slot, R.H., Bosma, M., Inserra, M., Vetter, I., Verhoeven-Duif, N.M., Braun, K.P.J., Rivara, M., Koeleman, B.P.C.
ID
ZDB-PUB-200307-9
Date
2020
Source
PLoS One   15: e0219106 (Journal)
Registered Authors
Koeleman, B. P. C., van 't Slot, Ruben
Keywords
none
MeSH Terms
  • Animals
  • Anticonvulsants/pharmacology
  • Disease Models, Animal
  • Epilepsies, Myoclonic/metabolism
  • Epilepsies, Myoclonic/pathology*
  • Humans
  • Locomotion/drug effects
  • Morpholinos/metabolism
  • Mutagenesis
  • NAV1.1 Voltage-Gated Sodium Channel/chemistry
  • NAV1.1 Voltage-Gated Sodium Channel/genetics
  • NAV1.1 Voltage-Gated Sodium Channel/metabolism*
  • NAV1.6 Voltage-Gated Sodium Channel/chemistry
  • NAV1.6 Voltage-Gated Sodium Channel/genetics
  • NAV1.6 Voltage-Gated Sodium Channel/metabolism*
  • Neurons/drug effects
  • Neurons/metabolism
  • Pentylenetetrazole/pharmacology
  • Phenotype
  • RNA, Guide, Kinetoplastida/metabolism
  • RNA, Messenger/metabolism
  • Voltage-Gated Sodium Channel Agonists/pharmacology
  • Voltage-Gated Sodium Channel Blockers/pharmacology
  • Zebrafish
  • Zebrafish Proteins/chemistry
  • Zebrafish Proteins/genetics
  • Zebrafish Proteins/metabolism*
  • gamma-Aminobutyric Acid/metabolism
PubMed
32134913 Full text @ PLoS One
Abstract
Dravet syndrome is caused by dominant loss-of-function mutations in SCN1A which cause reduced activity of Nav1.1 leading to lack of neuronal inhibition. On the other hand, gain-of-function mutations in SCN8A can lead to a severe epileptic encephalopathy subtype by over activating NaV1.6 channels. These observations suggest that Nav1.1 and Nav1.6 represent two opposing sides of the neuronal balance between inhibition and activation. Here, we hypothesize that Dravet syndrome may be treated by either enhancing Nav1.1 or reducing Nav1.6 activity. To test this hypothesis we generated and characterized a novel DS zebrafish model and tested new compounds that selectively activate or inhibit the human NaV1.1 or NaV1.6 channel respectively. We used CRISPR/Cas9 to generate two separate Scn1Lab knockout lines as an alternative to previous zebrafish models generated by random mutagenesis or morpholino oligomers. Using an optimized locomotor assay, spontaneous burst movements were detected that were unique to Scn1Lab knockouts and disappear when introducing human SCN1A mRNA. Besides the behavioral phenotype, Scn1Lab knockouts show sudden, electrical discharges in the brain that indicate epileptic seizures in zebrafish. Scn1Lab knockouts showed increased sensitivity to the GABA antagonist pentylenetetrazole and a reduction in whole organism GABA levels. Drug screenings further validated a Dravet syndrome phenotype. We tested the NaV1.1 activator AA43279 and two novel NaV1.6 inhibitors MV1369 and MV1312 in the Scn1Lab knockouts. Both type of compounds significantly reduced the number of spontaneous burst movements and seizure activity. Our results show that selective inhibition of NaV1.6 could be just as efficient as selective activation of NaV1.1 and these approaches could prove to be novel potential treatment strategies for Dravet syndrome and other (genetic) epilepsies. Compounds tested in zebrafish however, should always be further validated in other model systems for efficacy in mammals and to screen for potential side effects.
Genes / Markers
Figures
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Expression
Phenotype
Mutations / Transgenics
Human Disease / Model
Sequence Targeting Reagents
Fish
Antibodies
Orthology
Engineered Foreign Genes
Mapping