STK-001 Surrogate Restores the Excitability of Parvalbumin-positive Fast-spiking Interneurons in a Mouse Model of Dravet Syndrome
Abstract number :
3.05
Submission category :
1. Basic Mechanisms / 1D. Mechanisms of Therapeutic Interventions
Year :
2022
Submission ID :
2204673
Source :
www.aesnet.org
Presentation date :
12/5/2022 12:00:00 PM
Published date :
Nov 22, 2022, 05:26 AM
Authors :
Luis Lopez-santiago, PhD – University of Michigan Medical School; Yukun Yuan, PhD – Associate Research Scientist, Pharmacology, University of Michigan Medical School; Nicholas Denomme, Graduate Student – Pharmacology – University of Michigan Medical School; Chunling Chen, MD – Pharmacology – University of Michigan Medical School; Anne Christiansen, PhD – Stoke Therapeutics; Gene Liau, PhD – Stoke Therapeutics; Lori Isom, PhD – Professor, Pharmacology, University of Michigan Medical School
This abstract has been invited to present during the Basic Science Poster Highlights poster session
Rationale: Dravet syndrome (DS) is a severe developmental and epileptic encephalopathy characterized by high seizure frequency and severity, intellectual disability, and a high risk of sudden unexpected death in epilepsy (SUDEP). The majority of patients with DS carry de novo variants in SCN1A leading to haploinsufficiency of the voltage-gated sodium channel a subunit Nav1.1. Scn1a+/- DS mouse models recapitulate many patient phenotypes, including severe seizures and SUDEP. It has been shown previously that DS mice have reduced excitability of parvalbumin-positive (PV+) fast-spiking (FS) interneurons leading to disinhibition. We showed that treatment of DS mice with the antisense oligonucleotide (ASO) STK-001 increased the endogenous expression of Scn1a mRNA and protein, reduced the incidence of electrographic seizures, and decreased the SUDEP rate of Scn1a+/- DS mice. Here, we investigated the effects of STK-001 surrogate ASO or vehicle treatment on the excitability of cortical PV+ FS interneurons in DS mice.
Methods: F1:129 x C57Bl/6J Scn1a+/- x PV dt-tomato (DS) and F1:129 x C57Bl/6J Scn1a+/+ x PV dt-tomato (WT) mice were treated with a single intracerebroventricular (ICV) injection of STK-001 surrogate or vehicle at postnatal day (P)2. Coronal brain slices (~200 µm) were prepared from the somatosensory cortices at P21-P25 (both sexes). The whole cell current-clamp recording technique was used to record action potentials (APs) and firing patterns of individual PV+ interneurons in slices under epifluorescence.
Results: PV+ interneurons in cortical slices prepared from untreated or vehicle-treated Scn1a+/- DS mice had a lower threshold for AP firing, but fired less, and their firing was highly sensitive to depolarization block compared to WT. While there were no significant differences in AP amplitude or threshold for AP initiation between genotypes, APs of Scn1a+/- DS PV+ interneurons had significantly slower rising and decay rates and increased half-amplitude durations compared to WT. Treatment with STK-001 surrogate ASO restored Scn1a+/- DS PV+ interneuron firing patterns to WT values. Scn1a+/- DS and WT PV+ interneurons showed similar spontaneous inhibitory post-synaptic current (sIPSC) amplitudes, but the sIPSC frequency of Scn1a+/- DS PV+ interneurons was significantly lower, suggesting reduced presynaptic GABA release. Treatment with STK-001 surrogate ASO restored Scn1a+/- DS PV+ interneuron sIPSC frequency to WT values.
Conclusions: STK-001 surrogate ASO treatment restores Scn1a+/- DS PV+ interneuron excitability and GABA release in a DS mouse model.
Funding: Funded by NIH NS088571 to LLI, a grant from Stoke Therapeutics to LLI, and a University of Michigan Department of Pharmacology Centennial Graduate Fellowship to ND.
Basic Mechanisms