The Use of Organoids in Epilepsy Research

Human brain organoids derived from human pluripotent stem cells are a powerful testing platform to model and study epilepsy. These organoids may be advantageous over traditional rodent models which do not always exhibit human pathology, possibly due to differences in size, complexity, and gene expression patterns between rodent and human brains. Due to their greater structural complexity and a diverse population of neurons, three-dimensional brain organoids are a useful tool to model epilepsy and test potential therapies.

Dr. Parent speaks about recent advances in techniques using brain organoids and their use in epilepsy research.

Download Full Transcript

This seminar is part of CURE Epilepsy’s Frontiers in Research Seminar Series. This program is generously supported by the Nussenbaum-Vogelstein Family and aims to help educate and expose researchers, clinicians, and students to exciting epilepsy research and also provide opportunities for young investigators to interact with leaders in the field.

About the Speaker
The seminar will be presented by former CURE Epilepsy grantee Jack Parent, MD, William J Herdman Professor of Neurology and Co-Director of the Epilepsy Program at the University of Michigan.

Q&A with Dr. Jack Parent

Did you see evidence of variable or incomplete X inactivation in the female organoids?

Dr. Parent: That’s a really good question. When we started the PCDH19 studies, we started with female patient-derived IPS cells. We were doing 2D cultures. And we saw evidence for X inactivation, which we wanted. But in any given culture, we didn’t know what percentage were expressing the mutant and what percentage of cells were expressing the wildtype, and it would be just too much work to try to figure that out for every experiment. I think one of the reasons they’re asking the question is with prolonged passaging, you can get erosion of X inactivation for some genes in human pluripotent stem cells. So because of that problem, we changed approaches and we took complete knockout and wildtype and mixed the two in order to make a mosaic model where we didn’t have to worry about escape from X inactivation. That’s an important point.

Have you used electrophysiology to assess abnormal activity in the STRADA organoids, and if so, did you use any mTOR inhibitor to rescue it?

Dr. Parent: Both very good questions. Louis has done some experiments using rapamycin to rescue of the morphological phenotype. It rescues the megalencaphaly in the budding phenotype. In terms of the physiology, we published some work with 2D cultures looking at the physiology of the STRADA organoids. We see some changes, but it’s minor. And those are with dual SMAD differentiation of excitatory cortical neurons. But we think the best approach is going to be combining excitatory and inhibitory fusion organoids. We have not done that yet in STRADA, and that’s one of the things we want to do, looking at MEA recordings, but also putting in the patch electrodes to record local field potentials like the UCLA group is doing. I actually went on sabbatical there to learn it.

In your PMSE organoid model, you talked about how you see these different phenotypes at different ages at different time points for the organoids. Do you have an idea of how that might correspond to the human brain development age?

Dr. Parent: That’s a good question. At the time points we’re looking, we probably never got later than mid-second trimester stages. To get to third trimester and even postnatal stages, you really have to go nine months a year. It really is like the time course of human development. So you really have to culture them very long. It makes for very long experiments and unhappy grad students and postdocs. People have cultured them for four years, even longer.

The information contained herein is provided for general information only and does not offer medical advice or recommendations. Individuals should not rely on this information as a substitute for consultations with qualified health care professionals who are familiar with individual medical conditions and needs. CURE strongly recommends that care and treatment decisions related to epilepsy and any other medical condition be made in consultation with a patient’s physician or other qualified health care professionals who are familiar with the individual’s specific health situation.