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XB-ART-59846
Front Cell Neurosci 2023 Jan 01;17:1175895. doi: 10.3389/fncel.2023.1175895.
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Epilepsy in a mouse model of GNB1 encephalopathy arises from altered potassium (GIRK) channel signaling and is alleviated by a GIRK inhibitor.

Colombo S , Reddy HP , Petri S , Williams DJ , Shalomov B , Dhindsa RS , Gelfman S , Krizay D , Bera AK , Yang M , Peng Y , Makinson CD , Boland MJ , Frankel WN , Goldstein DB , Dascal N .


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De novo mutations in GNB1, encoding the Gβ1 subunit of G proteins, cause a neurodevelopmental disorder with global developmental delay and epilepsy, GNB1 encephalopathy. Here, we show that mice carrying a pathogenic mutation, K78R, recapitulate aspects of the disorder, including developmental delay and generalized seizures. Cultured mutant cortical neurons also display aberrant bursting activity on multi-electrode arrays. Strikingly, the antiepileptic drug ethosuximide (ETX) restores normal neuronal network behavior in vitro and suppresses spike-and-wave discharges (SWD) in vivo. ETX is a known blocker of T-type voltage-gated Ca2+ channels and G protein-coupled potassium (GIRK) channels. Accordingly, we present evidence that K78R results in a gain-of-function (GoF) effect by increasing the activation of GIRK channels in cultured neurons and a heterologous model (Xenopus oocytes)-an effect we show can be potently inhibited by ETX. This work implicates a GoF mechanism for GIRK channels in epilepsy, identifies a new mechanism of action for ETX in preventing seizures, and establishes this mouse model as a pre-clinical tool for translational research with predicative value for GNB1 encephalopathy.

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Genes referenced: kcnj3

References [+] :
Asinof, Dynamin 1 isoform roles in a mouse model of severe childhood epileptic encephalopathy. 2016, Pubmed