Global transgenic upregulation of KCC2 confers enhanced diazepam efficacy in treating sustained seizures.

Abstract

Reduced anticonvulsant efficacy of benzodiazepines is a problem in the treatment of status epilepticus, with up to 50% of patients failing to respond to their first dose. KCC2 is a neuronal K+ -Cl- co-transporter that helps set and maintain intracellular Cl- concentrations. KCC2 functional downregulation is a potential contributor to benzodiazepine resistance. We tested this idea using male and female doxycycline-inducible, conditional transgenic mice to increase the functional expression of KCC2 in pyramidal neurons. We administered mice with two doses of the chemoconvulsant kainic acid (5 mg/kg, i.p.) 60 min apart and quantified the resultant seizures with electroencephalography (EEG) recordings. Overexpression of KCC2 prior to the chemoconvulsant challenge did not affect seizure latency or other measures of seizure severity, but it did increase diazepam's efficacy in stopping EEG seizures. Spike rate, time in seizure, and EEG spectral power following diazepam (5 mg/kg, i.p) were all significantly lower in KCC2 overexpression mice as compared to control mice. Our results indicate that, in the context of benzodiazepine resistance during sustained seizures, addressing impaired Cl- homeostasis alone appreciably improves the efficacy of γ-aminobutyric acid (GABA)ergic inhibition. We therefore suggest the simultaneous targeting of KCC2 and GABAA receptors as a pathway for improving current anticonvulsant therapeutic strategies.

• Authors: Dennis L Cheung, Matthew J Cooke, Chelsea S Goulton, Chanchanok Chaichim, Louis F Cheung, Ashor Khoshaba, Junichi Nabekura, Andrew J Moorhouse
• Journal: Epilepsia (Epilepsia) Vol. 63 Issue 1 Pg. e15-e22 (01 2022) ISSN: 1528-1167 [Electronic] United States
• PMID: 34791657 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: © 2021 International League Against Epilepsy.

Chemical References

• Anticonvulsants
• Symporters
• Benzodiazepines
• gamma-Aminobutyric Acid
• Diazepam

Topics

• Animals
• Anticonvulsants (pharmacology, therapeutic use)
• Benzodiazepines (therapeutic use)
• Diazepam (pharmacology, therapeutic use)
• Female
• Humans
• Male
• Mice
• Seizures (drug therapy, metabolism)
• Symporters (genetics)
• Up-Regulation
• gamma-Aminobutyric Acid (metabolism)