Closed loop therapies for genetic epilepsies.

Developmental and epileptic encephalopathies (DEEs) are the source of major life-threatening symptoms. Epilepsy is characterized symptomatically by recurrent, spontaneous seizures that is intrinsically mirrored by network hyperexcitability and hypersynchrony.
Issues with DEEs lie due to frequent pharmaco-resistance to anti-epileptic treatment which fail in seizure suppression. This is highly damaging to individuals with epilepsy, influencing cognitive function and commonly leading to intellectual and physical disabilities. One fatal outcome of the seizure phenotype in epilepsy is sudden unexpected death in epilepsy (SUDEP) which results in nearby 600 people dying per year in the UK.

Due to the genetic basis of myriad DEEs, advanced gene therapies pose a plausible treatment in rescuing seizure phenotypes, preventing cognitive effects and disability. This tool is, hypothetically, able to treat across the different epilepsies due to instigating therapeutic effect by influencing gene expression and subsequent properties of circuits where seizure phenotypes originate. One therapy already engineered within the department uses an activity-dependent, cell autonomous mechanism based on the cFos promoter driving expression of Kv1.1, a voltage gated potassium channel. Increase in activity of circuits activates this therapy and has been shown to specifically reduce seizures in mesial temporal lobe epilepsy when treating the epileptic focus.
Albeit this therapy has been engineered, a gap to bridge is utilising these approaches in whole brain strategies that can be employed across other severe genetic-based epilepsies where the epileptic focus is unknown or difficult to define. Thus, providing a generalised closed loop system that can be implemented as a therapeutic tool for seizure suppression across myriad severe genetic-based epilepsies. Consequently, this forms the major aim and hypothesis of the project.

Initially, this hypothesis will be explored in wildtype cohorts to ensure there is no effect when implementing this therapy whole brain, not localised, on the normal behavioural of mice. For example, using behavioural paradigms such as fear conditioning. In parallel to utilising this previously established activity dependent, cell autonomous gene therapy, one other gene therapy, utilising overexpression of a novel engineered GluCl, a glutamate-gated Cl--channel able to activate by pathological increase in glutamate concentration and in turn inhibits synaptic transmission, can also be implemented in a comparative approach to further validate the use of generalised closed loop systems to rescue seizure phenotype.
Once this has been established, these therapies will be experimentally tested first in a model of severe genetic epilepsies such as Dravet syndrome and then in a second model, such as KCNT1 migrating multi-focal epilepsy. By employing both therapies in two severe genetic epilepsies it will provide insight on whether this gene therapies can be used as a generalised approach. Additionally, to determine the origins of hyperexcitability, methods of ex vivo electrophysiology recordings, light-sheet microscopy for 3D whole brain imaging and in vivo approaches of neuropixel recordings will be employed. Specifically, using immunohistochemical approaches targeting early gene products, such as cFOS. Subsequently providing insight into the pathophysiology of severe genetic epilepsies. As mentioned previously, once the gene therapy is employed, mirrored recordings exploiting these methods can be utilized to understand the impact of application of the gene therapies on seizure phenotype. Consequently, validating the use of a generalised closed loop systems to diminish seizure phenotypes across severe genetic epilepsies.

Overall, this approach will progress the understanding of pathophysiology of severe genetic epilepsies, with an aim to bridge the gap in treatments by providing a tool of a generalised closed loop system of