From Drugs to Gene Editing for Developmental Epileptic Encephalopathies

Abstract

Since the rise of DNA sequencing technologies, it became apparent that the majority of diseases in humankind have – at least partly – a genetic origin.Many types of Epilepsy are also caused by DNA mutations. A DNA mutation in turn, is transcribed in messenger RNA (mRNA), which is translated to a malfunctioning protein. In the case of epilepsy, the malfunctioning protein can be a channel in the cell membrane of neurons, which would normally regulate how neurons communicate with each other. When malfunctioning, the neuronal excitability is changed with epileptic seizures as a result. Current treatment of epilepsy – antiseizure medication - is aimed at the consequence of a DNA mutation; the malfunctioning protein. In this thesis we set out to improve epilepsy treatment by targeting three levels of treatment; the protein, the mRNA, and the DNA. As an improvement to current channel-blocking protein-based drugs, we set out to improve selectivity by testing novel compounds in a zebrafish model of genetic epilepsy. Two types of compounds successfully improved the seizure phenotype; one that reduces activity of an ‘overactive’ channel-protein, and one that increases the activity of a channel-protein that is working less efficiently. Next, we tested three different technologies to enhance the expression of epilepsy genes, with the aim of altering mRNA levels to compensate for the malfunctioning protein. We found that, while some of them work, there was toxicity that should be further studied before next steps towards possible implementation can be considered. Finally, we tested if two known DNA mutations that lead to epilepsy can be repaired using geneediting technologies. In patient-derived stem cells, we successfully removed the DNA mutation, highlighting that in theory this would be a potential and powerful treatment option of genetic epilepsies in the future.