Modelling neuronal dysfunction in early onset epilepsies; a patient-centric approach

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Many babies present with epilepsy in the first year of life, sadly resulting in severe disability and shortened lifespan. One form of epilepsy is known as "Epilepsy of Infancy with Migrating Focal Seizures (EIMFS)" in which affected babies have very frequent seizures, often up to sixty per day, which usually do not respond to currently available medications. Abnormalities in three genes, known as KCNT1, SLC12A5 and SCN2A can cause EIMFS. These genes make important proteins in the brain that, when abnormal, cause seizures in young babies.However, it is not clear how they lead to epilepsy. Using a new state-of-the art brain cell model made from skin cells taken from patients in the study, I will investigate how abnormalities in these genes lead to epilepsy and developmental problems in patients. Skin cells from each patient will be converted into stem cells. Stem cells have the potential to convert into any of the cell types in the body. Once the stem cells are formed, gene editing technology will be used to correct the mutation in some of the cells. This will allow me to verify that the effect we see in the abnormal neurones is just due to the abnormality in KCNT1, SLC12A5or SCN2A and not due to other genes. The stem cells will be converted into three dimensional structures or organoids which after maturation for several months will be made up of layers of neurons, effectively mini-brains. These min-brains contain mostly excitatory neutrons. Excitatory neutrons cause brain excitation, whereas inhibitory neurons slow down or prevent brain excitation. I will convert some of the stem cells into 3D collections of inhibitory neurons which will be fused together with the organoids. This is to ensure all the correct types of neurons are present and that they can form connections with each other. I will test the electrical properties of the brain cells and how they connect with other brain cells. If we can work out precisely how the abnormal genes cause seizures, this may help us identify better drugs for both this form of epilepsy and other epilepsies. As part of the project I will also test a form of gene therapy, where a normal copy of the gene is replaced in the brain cell where it is missing. In addition, I will also be testing a different treatment, "antisense oligonucleotides". An oligonucleotide is a short synthetic DNA strand which has the mirror image code (antisense) of the DNA it is trying to bind to. The antisense oligonucleotide is designed to block and inactivate the abnormal mutated DNA. My aim is to improve our understanding of how these abnormal genes lead to epilepsy and development problems which will help in the development of new treatments, with the ultimate aim of improving quality of life for my patients and their families.