Monash ‘Neuroscience in a Flash’ Competition 2020

Title of presentation: Development of personalized ‘disease-in-a-dish’ model of focal cortical dysplasia using induced pluripotent stem cells
Department: CCS, Alfred

Abstract: Focal cortical dysplasia (FCD) is a type of malformation of cerebral cortex and abnormal cytoarchitecture linked to disruption in the mTOR pathway, and is among the most common pathologies causing drug-resistant epilepsy. A range of somatic and germline mutations in mTOR pathway genes have been associated with FCD. Conventional animal-based models are unable to recapitulate the complex pathophysiological mechanisms of FCD. Here, we developed a ‘personalised’ human-based model using induced pluripotent stem cells (iPSCs) obtained from individual patients with FCD. Methods: A patients with loss-of-function mutation in the mTOR pathway gene, DEPDC5, was identified through whole genome sequencing. Peripheral blood mononuclear cells were prepared from the patients to generate iPSCs. Using these iPSCs, monolayer neurons and 3D brain organoids were generated. Their morphology, neuronal gene expression and electrical activity was studied using immunocytochemistry and microelectrode array (MEA) analysis.

Results: Monolayer neurons derived from patients’ iPSCs expressed pre-plate (TBR1), deep layer (CTIP2) and surface layer (Satb2) cortical neuronal markers, including general neuronal markers (Map2,Tau, β-III) and calcium binding protein (Calbindin). Action potential based neuronal activity measured by MEA showed higher spike frequency in monolayer neurons derived from patients compared to control neurons. 3D brain organoids have been generated; characterization is underway and will be presented. Discussion: We have developed ‘disease-in-a-dish’ models from patients with FCD. These models may provide novel insight into pathophysiological mechanisms that underpin FCD-related drug-resistant epilepsy involving mTOR pathway, and could be used as ‘personalised’ drug screening platform in individual patients with FCD.