Removal of KCNQ2 from parvalbumin-expressing interneurons improves anti-seizure efficacy of retigabine

Junzhan Jing, Corrinne Dunbar, Alina Sonesra, Ana Chavez, Suhyeorn Park, Ryan Yang, Heun Soh, Maxwell Lee, Anastasios V. Tzingounis, Edward C. Cooper, Xiaolong Jiang, Atul Maheshwari

Research output: Contribution to journalArticlepeer-review

6 Scopus citations

Abstract

Anti-seizure drug (ASD) targets are widely expressed in both excitatory and inhibitory neurons. It remains unknown if the action of an ASD upon inhibitory neurons could counteract its beneficial effects on excitatory neurons (or vice versa), thereby reducing the efficacy of the ASD. Here, we examine whether the efficacy of the ASD retigabine (RTG) is altered after removal of the Kv7 potassium channel subunit KCNQ2, one of its drug targets, from parvalbumin-expressing interneurons (PV-INs). Parvalbumin-Cre (PV-Cre) mice were crossed with Kcnq2-floxed (Kcnq2fl/fl) mice to conditionally delete Kcnq2 from PV-INs. In these conditional knockout mice (cKO, PV-Kcnq2fl/fl), RTG (10 mg/kg, i.p.) significantly delayed the onset of either picrotoxin (PTX, 10 mg/kg, i.p)- or kainic acid (KA, 30 mg/kg, i.p.)-induced convulsive seizures compared to vehicle, while RTG was not effective in wild-type littermates (WT). Immunostaining for KCNQ2 and KCNQ3 revealed that both subunits were enriched at axon initial segments (AISs) of hippocampal CA1 PV-INs, and their specific expression was selectively abolished in cKO mice. Accordingly, the M-currents recorded from CA1 PV-INs and their sensitivity to RTG were significantly reduced in cKO mice. While the ability of RTG to suppress CA1 excitatory neurons in hippocampal slices was unchanged in cKO mice, its suppressive effect on the spike activity of CA1 PV-INs was significantly reduced compared with WT mice. In addition, the RTG-induced suppression on intrinsic membrane excitability of PV-INs in WT mice was significantly reduced in cKO mice. These findings suggest that preventing RTG from suppressing PV-INs improves its anticonvulsant effect.

Original languageEnglish (US)
Article number114141
JournalExperimental Neurology
Volume355
DOIs
StatePublished - Sep 2022
Externally publishedYes

Keywords

  • hippocampus
  • Interneurons
  • Kv7 channel
  • Parvalbumin
  • Retigabine
  • Seizure

ASJC Scopus subject areas

  • Neurology
  • Developmental Neuroscience

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