Viral vector–mediated expression of NaV1.1, after seizure onset, reduces epilepsy in mice with Dravet syndrome
Saja Fadila, … , Eric J. Kremer, Moran Rubinstein
Saja Fadila, … , Eric J. Kremer, Moran Rubinstein
Published May 16, 2023
Citation Information: J Clin Invest. 2023;133(12):e159316. https://doi.org/10.1172/JCI159316.
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Research Article Neuroscience

Viral vector–mediated expression of NaV1.1, after seizure onset, reduces epilepsy in mice with Dravet syndrome

Abstract

Dravet syndrome (DS), an intractable childhood epileptic encephalopathy with a high fatality rate, is typically caused by loss-of-function mutations in one allele of SCN1A, which encodes NaV1.1, a 250-kDa voltage-gated sodium channel. In contrast to other epilepsies, pharmaceutical treatment for DS is limited. Here, we demonstrate that viral vector–mediated delivery of a codon-modified SCN1A open reading frame into the brain improves DS comorbidities in juvenile and adolescent DS mice (Scn1aA1783V/WT). Notably, bilateral vector injections into the hippocampus and/or the thalamus of DS mice increased survival, reduced the occurrence of epileptic spikes, provided protection from thermally induced seizures, corrected background electrocorticographic activity and behavioral deficits, and restored hippocampal inhibition. Together, our results provide a proof of concept for the potential of SCN1A delivery as a therapeutic approach for infants and adolescents with DS-associated comorbidities.

Authors

Saja Fadila, Bertrand Beucher, Iria González Dopeso-Reyes, Anat Mavashov, Marina Brusel, Karen Anderson, Caroline Ismeurt, Ethan M. Goldberg, Ana Ricobaraza, Ruben Hernandez-Alcoceba, Eric J. Kremer, Moran Rubinstein

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Figure 4

CAV-2–mediated NaV1.1 activity and in vivo location.

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CAV-2–mediated NaV1.1 activity and in vivo location. (A and B) Voltage-c...
(A and B) Voltage-current relationship (A) and the biophysical properties (B) of sodium currents following expression of CAV-SCN1A in DK cells. The half voltage of activation/inactivation was –30.4 ± 0.7 mV, and –65.73 ± 0.9 mV, respectively. (C and D) Sodium currents following expression of CAV-HA-SCN1A in DK cells. The half voltage of activation/inactivation was –30.6 ± 1.2 mV and –67.8 ± 1.8 mV, respectively. Insets in A and C show representative sodium currents (calibrators: 500 pA, 2 ms). The empty symbols depict the currents from DK cells infected with CAV-GFP (n = 10, presented in A and D), and closed symbols depict CAV-SCN1A (n = 9) or CAV-HA-SCN1A (n = 7). (E–I) CAV-HA-SCN1A was injected bilaterally into the hippocampus of adult mice. HA immunoreactivity is shown in brown; all sections were counterstained using cresyl violet. (E) Low-magnification micrographs showing the presence of HA-immunoreactive cells in different layers of the CA1 region, 2 weeks after injection. (F–I) High magnification of the red boxes in E showing HA-immunoreactive cells in the layers of the CA1 region. The immunoreactivity is present in the somata and in the fibers (arrow heads). (J–L) Confocal images showing mCitrine (green) in NeuN+ cells, but not in GFAP+ cells (magenta) in the CA1 of an adult mouse. (M–O) High magnification of the CA1 showing the presence of mCitrine (green) in GABAergic cells (magenta, yellow arrows). (P–R) Z-stack of confocal images showing mCitrine+ (green) in parvalbumin (PV) immunoreactive cells (magenta, yellow arrows). Scale bars: 1 mm (E), 10 μm (F–I), 25 μm (J–L), 50 μm (M–O), and 25 μm (P–R). PL, pyramidal cell layer; SO, stratum oriens; SR, stratum radiatum. (S and T) Ten days after hippocampal injection of CAV-GFP (n = 2 mice) or CAV-HA-SCN1A (n = 2 mice), the hippocampi (S) and neocortex (T) were isolated and membrane bound proteins were extracted. Western blot analyses using anti-HA and anti-NaV1.1 are shown. ATPase was used as an internal control.