In vitro effects of eslicarbazepine (S-licarbazepine) as a potential precision therapy on SCN8A variants causing neuropsychiatric disorders

Bayraktar E., Liu Y., Sonnenberg L., Hedrich U. B. S., Sara Y., Eltokhi A., ...More

British Journal of Pharmacology, vol.180, no.8, pp.1038-1055, 2023 (SCI-Expanded) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 180 Issue: 8
  • Publication Date: 2023
  • Doi Number: 10.1111/bph.15981
  • Journal Name: British Journal of Pharmacology
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, BIOSIS, CAB Abstracts, Chemical Abstracts Core, Chimica, CINAHL, EMBASE, MEDLINE, Veterinary Science Database
  • Page Numbers: pp.1038-1055
  • Keywords: developmental and epileptic encephalopathy, eslicarbazepine, epilepsy, Na(V)1, 6, precision medicine, SCN8A, S-licarbazepine, sodium channel blocker
  • Hacettepe University Affiliated: Yes


© 2022 The Authors. British Journal of Pharmacology published by John Wiley & Sons Ltd on behalf of British Pharmacological Society.Background and Purpose: Variants in SCN8A, the NaV1.6 channel's coding gene, are characterized by a variety of symptoms, including intractable epileptic seizures, psychomotor delay, progressive cognitive decline, autistic features, ataxia or dystonia. Standard anticonvulsant treatment has a limited impact on the course of disease. Experimental Approach: We investigated the therapeutic potential of eslicarbazepine (S-licarbazepine; S-lic), an enhancer of slow inactivation of voltage gated sodium channels, on two variants with biophysical and neuronal gain-of-function (G1475R and M1760I) and one variant with biophysical gain-of-function but neuronal loss-of-function (A1622D) in neuroblastoma cells and in murine primary hippocampal neuron cultures. These three variants cover the broad spectrum of NaV1.6-associated disease and are linked to representative phenotypes of mild to moderate epilepsy (G1475R), developmental and epileptic encephalopathy (M1760I) and intellectual disability without epilepsy (A1622D). Key Results: Similar to known effects on NaV1.6 wildtype channels, S-lic predominantly enhances slow inactivation on all tested variants, irrespective of their particular biophysical mechanisms. Beyond that, S-lic exhibits variant-specific effects including a partial reversal of pathologically slowed fast inactivation dynamics (A1622D and M1760I) and a trend to reduce enhanced persistent Na+ current by A1622D variant channels. Furthermore, our data in primary transfected neurons reveal that not only variant-associated hyperexcitability (M1760I and G1475R) but also hypoexcitability (A1622D) can be modulated by S-lic. Conclusions and Implications: S-lic has not only substance-specific effects but also variant-specific effects. Personalized treatment regimens optimized to achieve such variant-specific pharmacological modulation may help to reduce adverse side effects and improve the overall therapeutic outcome of SCN8A-related disease.