Authors :
Presenting Author: Nicole Hawkins, PhD – Northwestern University Feinberg School of Medicine
Jean-Marc DeKeyser, MS – Northwestern University Feinberg School of Medicine
Jennifer Kearney, PhD – Northwestern University Feinberg School of Medicine
Alfred George, MD – Northwestern University Feinberg School of Medicine
Rationale:
Pathogenic variants in ATP1A3 are associated with a spectrum of rare, neurological disorders, including alternating hemiplegia of childhood (AHC). AHC presents early in life with recurrent episodes of hemiplegia or dystonia, and 40-50% of cases exhibit comorbid epilepsy. We generated Atp1a3G947R mice to model the recurrent ATP1A3-p.G947R variant, and assessed spontaneous and induced seizures, EEG abnormalities and survival.
Methods:
Heterozygous Atp1a3G947R mice (designated R/+) were generated using CRISPR/Cas9 in C57BL/6J (B6) embryos. N1 mice confirmed for G947R were bred to B6 (Jackson Labs, #000064) to establish the line. Each experiment used a separate cohort of mice, balanced by sex. Susceptibility to seizures and lethality induced by kainic acid (KA; 25 mg/kg, IP) was assessed using a modified Racine scale (n=16-22/genotype). Latency to seizures induced by flurothyl (20 μL/min) was determined (n=19-20/genotype). Maximal electroshock (MES) test was conducted at 60 Hz, 0.5 pulse width, 0.2 sec duration and 38 mA current (n=9-10/genotype). Handling-induced seizures were assessed by continuous video monitoring of mice implanted with prefabricated headmounts (~168 hours/mouse, n=13/genotype). Survival was compared by Kaplan Meier analysis (n=161-178/genotype).
Results:
In addition to motor impairments that recapitulate features of AHC, heterozygous R/+ mice exhibited elevated sensitivity to induced seizures, handling-induced seizures and premature lethality. Following exposure to KA, R/+ mice progressed faster than WT mice to stage 3 (p< 0.009