Working with patient-derived stem cell lines and matched healthy control lines, the project grew TSC and control organoids and recorded their electrical activity repeatedly over several months of development. A custom open-source software pipeline was built to detect and characterise high-frequency oscillations - a specific electrical pattern that clinicians use to locate epilepsy-causing tissue in patients. The same analysis was applied both to the organoid recordings and to clinical recordings from patients, allowing a direct comparison between model and human disease.
To identify the cells responsible, the project labelled and recorded from a particular class of inhibitory nerve cell that arises during a defined stage of development, combining electrical recordings, single-cell measurements of cell properties, and detailed imaging of cell structure. Finally, the project tested several clinically relevant compounds, applied over the long term during the critical developmental window, to see whether they could prevent the disease signature from appearing.
The project successfully built a human organoid model that reproduces, in the laboratory, the same electrical biomarker used clinically to identify epilepsy-causing tissue in TSC patients. The electrical signatures that emerge in the TSC organoids closely match key features of those recorded from patients, establishing the model as a faithful and tractable system for studying the earliest stages of human epileptogenesis.
The project identified a specific developmental subtype of inhibitory nerve cell as a driver of the abnormal network synchronisation that underlies the epileptic signature. It further showed that this cell population is over-produced in TSC organoids and that reducing it lessens the abnormal activity.
Most importantly, the project demonstrated that long-term inhibition of a particular cell-signalling pathway, applied during the critical developmental window, prevents the epileptic phenotype from emerging - both in terms of electrical activity and of the underlying changes in cell structure and number. To the project's knowledge, this is the first demonstration of pharmacological prevention of epileptogenesis in a human laboratory model.
