Protective effect of CACNA1A deficiency against seizure in the CACNA1A-CELSR2 digenic knockdown flies

Abstract

The vast majority of medically intractable epilepsy cases can be traced to polygenic backgrounds, and pathogenic variants contribute to genetic risk in the complex inheritance of this common disorder. We generated monogenic and digenic drosophila models by knock-down of two epilepsy-associated genes, CACNA1A and CELSR2, with impacts on intersynaptic calcium activities. Monogenic knockdown of CACNA1A or CELSR2 could induce seizure-like behavior in flies. Interestingly, seizure behavior tests showed that CACNA1A deficiency could attenuate the seizure-like activities of the CACNA1A-CELSR2 digenic knockdown flies. The protective effect of CACNA1A deficiency was quantitatively fitted with multiple linear regression equation based on the seizure rates. In calcium imaging results, CACNA1A monogenic knockdown flies showed higher frequency of large spikes calcium activity than that of wild-type flies. That would be the neural base of the seizure in CACNA1A deficiency flies. However, the area under curve of calcium activity showed no difference between CACNA1A monogenic knockdown flies and wild-type flies. The calcium imaging results could partially illustrate the mechanism of the protective effect of CACNA1A deficiency. Furthermore, our study could be an ideal strategy to study polygenic effect on epilepsy by using animal model.