PUBLICATION

Phenotypic Characterization of Larval Zebrafish (Danio rerio) with Partial Knockdown of the cacna1a Gene

Authors
Gawel, K., Turski, W.A., van der Ent, W., Mathai, B.J., Kirstein-Smardzewska, K.J., Simonsen, A., Esguerra, C.V.
ID
ZDB-PUB-191227-1
Date
2019
Source
Molecular neurobiology   57(4): 1904-1916 (Journal)
Registered Authors
Esguerra, Camila V., Gawel, Kinga Aurelia, Kirstein-Smardzewska, Karolina Joanna, Mathai, Benan John, Simonsen, Anne, van der Ent, Wietske
Keywords
Antiseizure drugs, CACNA1A gene, Epilepsy, Loss of function, Touch response, Zebrafish
MeSH Terms
  • Animals
  • Behavior, Animal/drug effects
  • Brain/metabolism
  • Electroencephalography
  • Gene Expression Regulation, Developmental/drug effects
  • Gene Knockdown Techniques*
  • Humans
  • Larva/genetics
  • Morpholinos/pharmacology
  • Motor Activity/drug effects
  • Phenotype
  • Touch
  • Zebrafish/genetics*
  • Zebrafish Proteins/genetics*
  • Zebrafish Proteins/metabolism
PubMed
31875924 Full text @ Mol. Neurobiol.
Abstract
The CACNA1A gene encodes the pore-forming α1 subunit of voltage-gated P/Q type Ca2+ channels (Cav2.1). Mutations in this gene, among others, have been described in patients and rodents suffering from absence seizures and episodic ataxia type 2 with/without concomitant seizures. In this study, we aimed for the first time to assess phenotypic and behavioral alterations in larval zebrafish with partial cacna1aa knockdown, placing special emphasis on changes in epileptiform-like electrographic discharges in larval brains. Whole-mount in situ hybridization analysis revealed expression of cacna1aa in the optic tectum and medulla oblongata of larval zebrafish at 4 and 5 days post-fertilization. Next, microinjection of two antisense morpholino oligomers (individually or in combination) targeting all splice variants of cacna1aa into fertilized zebrafish eggs resulted in dose-dependent mortality and decreased or absent touch response. Over 90% knockdown of cacna1aa on protein level induced epileptiform-like discharges in the optic tectum of larval zebrafish brains. Incubation of morphants with antiseizure drugs (sodium valproate, ethosuximide, lamotrigine, topiramate) significantly decreased the number and, in some cases, cumulative duration of epileptiform-like discharges. In this context, sodium valproate seemed to be the least effective. Carbamazepine did not affect the number and duration of epileptiform-like discharges. Altogether, our data indicate that cacna1aa loss-of-function zebrafish may be considered a new model of absence epilepsy and may prove useful both for the investigation of Cacna1a-mediated epileptogenesis and for in vivo drug screening.
Genes / Markers
Figures
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Expression
Phenotype
Mutations / Transgenics
Human Disease / Model
Sequence Targeting Reagents
Fish
Antibodies
Orthology
Engineered Foreign Genes
Mapping