Novel Knock-in Mouse Model of Genetic Atp1a3 Dysfunction (S52.006)

Abstract

Objective: To establish a knock-in mouse model containing the E815K mutation, which causes the most severe phenotype of Alternating Hemiplegia of Childhood (AHC). Background: De novo mutations causing dysfunction of the ATP1α3 subunit of Na+/K+ pump in neurons cause AHC, that manifests as paroxysmal episodes of hemiplegia, dystonia, behavior abnormalities and seizures. Methods: E815K heterozygous mice were generated in collaboration with the Duke Transgenic Mouse Facility. We compared E815K mice to Wild-type (WT) littermates using behavioral and neurophysiological tests to evaluate behavior, memory and motor dysfunction. Mutant and WT mice were implanted with bipolar electrodes and monitored with video EEG and kindling to evaluate predisposition to seizures. Frozen sections were obtained through the hippocampus and immunoreactivity to GABAergic cell markers was quantified using Stereo Investigator. Data were analyzed by One-way ANOVA, student T-test or Fisher’s exact test. P-values < 0.05 were significant. Results: 5 of 8 E815K mice had dystonia and 6 of 8 had hemiplegia versus 0 WT mice (p< 0.01) after forced swim. E815K mice took longer than WT to traverse the balance beam (p< 0.01) and had more hindlimb slips (p< 0.001); had shorter stride lengths and wider hind limb stance (p< 0.01) than WT; and E815K mice fell earlier than WT, and at lower speeds (p 40[percnt] reduction in GAD67+ and Parvalbumin+ neurons in E815K mice hippocampi compared to WT (p< 0.001). Conclusions: Our mouse model containing the E815K mutation of the Atp1a3 gene manifests clinical and neurophysiological features of AHC with histological evidence of GABAergic dysfunction in disease.Study supported by: the Cure AHC Foundation and the Duke Institute for Brain Sciences Research Incubator Award

Disclosure: Dr. Helseth has nothing to disclose. Dr. Adil has nothing to disclose. Dr. Linabarger has nothing to disclose. Dr. Arehart has nothing to disclose. Dr. Fainberg has nothing to disclose. Dr. Singh has nothing to disclose. Dr. Wetsel has nothing to disclose. Dr. Hochgeschwender has nothing to disclose. Dr. Hunanyan has nothing to disclose. Dr. Mikati has nothing to disclose.