Antisense oligonucleotide therapy forKCNT1encephalopathy

Abstract

Developmental and epileptic encephalopathies (DEE) are characterized by pharmacoresistant seizures with concomitant intellectual disability. Epilepsy of infancy with migrating focal seizures (EIMFS) is one of the most severe of these syndromes. De novo mutations in ion channels, including gain-of-function variants in KCNT1, have been found to play a major role in the etiology of EIMFS. Here, we test a potential precision therapeutic approach in KCNT1-associated DEE using a gene silencing antisense oligonucleotide (ASO) approach. The homozygous p.P924L (L/L) mouse model recapitulates the frequent, debilitating seizures and developmental compromise that are seen in patients. After a single intracerebroventricular bolus injection of a Kcnt1 gapmer ASO in symptomatic mice at postnatal day 40, seizure frequency was significantly reduced, behavioral abnormalities improved, and overall survival was extended compared to mice treated with a control ASO (non-hybridizing sequence). ASO administration at neonatal age was also well-tolerated and effective in controlling seizures and extending the lifespan of treated animals. The data presented here provides a proof of concept for ASO-based gene silencing as a promising therapeutic approach in KCNT1-associated epilepsies.

Discovery of the First Orally Available, Selective KNa1.1 Inhibitor: In Vitro and In Vivo Activity of an Oxadiazole Series

“…Compound 31 was assessed in vivo in the Kcnt1 L/L mouse model . Kcnt1 L/L mice (P32–40) were implanted with EEG electrodes to allow monitoring of electrographic seizure and interictal spike frequency.…”

“…Previous work has also linked activation of K Na 1.1 to the presence of subthreshold I Na (persistent I Na ) and enhancements in I Na are well-known to cause neuronal hyperexcitability . How variants in K Na 1.1 disrupt this regulation to produce a GoF phenotype is currently not well understood. , However, newly reported mouse models of KCNT1 GoF will invariably provide new insights. ,, …”

“…The effects of compound 31 on neuronal firing were evaluated in brain slices from WT mice and mice homozygous for mKcnt1-P905L (Kcnt1 L/L ). The Kcnt1 L/L mouse line recapitulates many key features of the human disease, including spontaneous seizures, high interictal spike frequency, and reduced survival . In brain slices prepared from p16–30 day old WT or Kcnt1 L/L mice, a current injection protocol was used to determine action potential firing at baseline and in the presence of 1 μM or 10 μM of compound 31 .…”

“…7,8 However, newly reported mouse models of KCNT1 GoF will invariably provide new insights. 7,9,10 KCNT1 channel mutants are located around three functional areas: the NAD + binding region situated in the C-terminus, the pore-forming region (between the S5 and S6 loops), and the RCK domains. All disease-causing variants are thought to be GoF and are associated with drug-resistant forms of infantile epilepsy such as the devastating epilepsy of infancy with migrating focal seizures (EIMFS) 3,11−13 or the less severe autosomal dominant nocturnal frontal lobe epilepsy (ADN-FLE).…”

“…The Kcnt1 L/L mouse line recapitulates many key features of the human disease, including spontaneous seizures, high interictal spike frequency, and reduced survival. 10 In brain slices prepared from p16−30 day old WT or Kcnt1 L/L mice, a current injection protocol was used to determine action potential firing at baseline and in the presence of 1 μM or 10 μM of compound 31. In neurons from WT mice, there was a nonsignificant trend toward a decrease in the total number of action potentials fired in the presence of 1 μM (p = 0.054, baseline 213.…”