Dravet syndrome patient-derived neurons suggest a novel epilepsy mechanism
Article first published online: 2 JUL 2013
© 2013 American Neurological Association
Annals of Neurology
Volume 74, Issue 1, pages 128–139, July 2013
How to Cite
Liu, Y., Lopez-Santiago, L. F., Yuan, Y., Jones, J. M., Zhang, H., O'Malley, H. A., Patino, G. A., O'Brien, J. E., Rusconi, R., Gupta, A., Thompson, R. C., Natowicz, M. R., Meisler, M. H., Isom, L. L. and Parent, J. M. (2013), Dravet syndrome patient-derived neurons suggest a novel epilepsy mechanism. Ann Neurol., 74: 128–139. doi: 10.1002/ana.23897
- Issue published online: 27 AUG 2013
- Article first published online: 2 JUL 2013
- Accepted manuscript online: 21 MAR 2013 11:31AM EST
- Manuscript Accepted: 1 MAR 2013
- Manuscript Revised: 25 FEB 2013
- Manuscript Received: 16 OCT 2012
- M.H.M. Grant Number: RC1NS068684
- L.L.I.. Grant Numbers: NS064245, NS076752
- Y.L.. Grant Number: MH059980
- NIH. Grant Number: T32HL007853
Neuronal channelopathies cause brain disorders, including epilepsy, migraine, and ataxia. Despite the development of mouse models, pathophysiological mechanisms for these disorders remain uncertain. One particularly devastating channelopathy is Dravet syndrome (DS), a severe childhood epilepsy typically caused by de novo dominant mutations in the SCN1A gene encoding the voltage-gated sodium channel Nav1.1. Heterologous expression of mutant channels suggests loss of function, raising the quandary of how loss of sodium channels underlying action potentials produces hyperexcitability. Mouse model studies suggest that decreased Nav1.1 function in interneurons causes disinhibition. We aim to determine how mutant SCN1A affects human neurons using the induced pluripotent stem cell (iPSC) method to generate patient-specific neurons.
Here we derive forebrain-like pyramidal- and bipolar-shaped neurons from 2 DS subjects and 3 human controls by iPSC reprogramming of fibroblasts. DS and control iPSC-derived neurons are compared using whole-cell patch clamp recordings. Sodium current density and intrinsic neuronal excitability are examined.
Neural progenitors from DS and human control iPSCs display a forebrain identity and differentiate into bipolar- and pyramidal-shaped neurons. DS patient-derived neurons show increased sodium currents in both bipolar- and pyramidal-shaped neurons. Consistent with increased sodium currents, both types of patient-derived neurons show spontaneous bursting and other evidence of hyperexcitability. Sodium channel transcripts are not elevated, consistent with a post-translational mechanism.
These data demonstrate that epilepsy patient–specific iPSC-derived neurons are useful for modeling epileptic-like hyperactivity. Our findings reveal a previously unrecognized cell-autonomous epilepsy mechanism potentially underlying DS, and offer a platform for screening new antiepileptic therapies. Ann Neurol 2013;74:128–139