Generation and validation of a zebrafish model of EAST (epilepsy, ataxia, sensorineural deafness and tubulopathy) syndrome.

Abstract

Recessive mutations in KCNJ10, which encodes an inwardly rectifying potassium channel, were recently identified as the cause of EAST syndrome, a severe and disabling multi-organ disorder consisting of epilepsy, ataxia, sensorineural deafness and tubulopathy that becomes clinically apparent with seizures in infancy. A Kcnj10 knockout mouse shows postnatal mortality and is therefore not suitable for drug discovery. Because zebrafish are ideal for in vivo screening for potential therapeutics, we tested whether kcnj10 knockdown in zebrafish would fill this need. We cloned zebrafish kcnj10 and demonstrated that its function is equivalent to that of human KCNJ10. We next injected splice- and translation-blocking kcnj10 antisense morpholino oligonucleotides and reproduced the cardinal symptoms of EAST syndrome - ataxia, epilepsy and renal tubular defects. Several of these phenotypes could be assayed in an automated manner. We could rescue the morphant phenotype with complementary RNA (cRNA) encoding human wild-type KCNJ10, but not with cRNA encoding a KCNJ10 mutation identified in individuals with EAST syndrome. Our results suggest that zebrafish will be a valuable tool to screen for compounds that are potentially therapeutic for EAST syndrome or its individual symptoms. Knockdown of kcnj10 represents the first zebrafish model of a salt-losing tubulopathy, which has relevance for blood pressure control.

• Authors: Fahad Mahmood, Monika Mozere, Anselm A Zdebik, Horia C Stanescu, Jonathan Tobin, Philip L Beales, Robert Kleta, Detlef Bockenhauer, Claire Russell
• Journal: Disease models & mechanisms (Dis Model Mech) Vol. 6 Issue 3 Pg. 652-60 (May 2013) ISSN: 1754-8411 [Electronic] England
• PMID: 23471908 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Kcnj10 (channel)
• Morpholinos
• Potassium Channels, Inwardly Rectifying

Topics

• Amino Acid Sequence
• Animals
• Base Sequence
• Cloning, Molecular
• Disease Models, Animal
• Gene Expression Profiling
• Gene Knockdown Techniques
• Hearing Loss, Sensorineural (genetics, pathology)
• Humans
• Intellectual Disability (genetics, pathology)
• Kidney (drug effects, pathology)
• Mice
• Molecular Sequence Data
• Morpholinos (pharmacology)
• Movement (drug effects)
• Phenotype
• Potassium Channels, Inwardly Rectifying (chemistry, genetics, metabolism)
• Reproducibility of Results
• Seizures (genetics, pathology)
• Xenopus
• Zebrafish (metabolism)