From Drugs to Gene Editing for Developmental Epileptic Encephalopathies

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.