Antisense oligonucleotides increase Scn1a expression and reduce seizures and SUDEP incidence in a mouse model of Dravet syndrome

Abstract

Dravet syndrome (DS) is an intractable developmental and epileptic encephalopathy caused largely by de novo variants in the SCN1A gene, resulting in haploinsufficiency of the voltage-gated sodium channel α subunit NaV1.1. Here, we used Targeted Augmentation of Nuclear Gene Output (TANGO) technology, which modulates naturally occurring, nonproductive splicing events to increase target gene and protein expression and ameliorate disease phenotype in a mouse model. We identified antisense oligonucleotides (ASOs) that specifically increase the expression of productive Scn1a transcript in human cell lines, as well as in mouse brain. We show that a single intracerebroventricular dose of a lead ASO at postnatal day 2 or 14 reduced the incidence of electrographic seizures and sudden unexpected death in epilepsy (SUDEP) in the F1:129S-Scn1a+/− × C57BL/6J mouse model of DS. Increased expression of productive Scn1a transcript and NaV1.1 protein was confirmed in brains of treated mice. Our results suggest that TANGO may provide a unique, gene-specific approach for the treatment of DS.

Nucleic Acid–Based Therapeutics in Orphan Neurological Disorders: Recent Developments

“…Stoke Therapeutics is using splice-switching NBTs that can prevent the inclusion of toxic exons and as a consequence increase transcription of productive mRNAs. This approach is termed Targeted Augmentation of Nuclear Gene Output platform (TANGO) ( Han et al, 2020 ). Stoke Therapeutics is currently conducting a phase 1/2a study of STK-001, an 2MOE PS ASO designed to skip a nonproductive exon in SCN1A gene, in Dravet syndrome ( Table 2 ; Stoke, 2020 ).…”

The dose makes the poison—Novel insights into Dravet syndrome and SCN1A regulation through nonproductive splicing

“…Haploinsufficiency is the generally accepted disease mechanism in Dravet nonproductive splicing events that could subsequently be reduced through specifically designed antisense oligonucleotides (ASO) [7]. This mechanism can be exploited therapeutically, and this strategy is currently implemented through a novel therapeutic method that targets these nonproductive splicing events.…”

“…This mechanism can be exploited therapeutically, and this strategy is currently implemented through a novel therapeutic method that targets these nonproductive splicing events. This method, referred to as Targeted Augmentation of Nuclear Gene Output (TANGO), resulted in restoration of SCN1A expression in a Dravet mouse model with a reduction of seizures and Sudden Unexpected Death in Epilepsy (SUDEP) [7]. This novel technology is currently moving to clinical trials.…”

Relative Quantification of NaV1.1 Protein in Mouse Brains Using a Meso Scale Discovery-Electrochemiluminescence (MSD-ECL) Method

“…This protocol was originally used in the research paper "Antisense oligonucleotides increase Scn1a expression and reduce seizures and SUDEP incidence in a mouse model of Dravet syndrome" (Han et al, 2020).…”