Authors :
Presenting Author: Olivia Hoffman, BS – University of Wisconsin-Madison
Anna Patterson, BS – University of Wisconsin-Madison; Emily Gohar, BS – University of Wisconsin-Madison; Emanuel Coleman, BS – Tufts University; Barry Schoenike, MS – University of Wisconsin-Madison; Claudia Espinosa-Garcia, PhD – Emory University; Felipe Paredes, PhD – Emory University; Raymond Dingledine, PhD – Professor, Department of Pharmacology & Chemical Biolog, Emory University; Jamie Maguire, PhD – Professor, Department of Neuroscience, Tufts University; Avtar Roopra, PhD – Professor, Department of Neuroscience, University of Wisconsin-Madison
Rationale: Epilepsy is a highly prevalent neurological disorder defined by the emergence of recurring, spontaneous seizures. Current anticonvulsant medications are not disease modifying and do not prevent epileptogenesis. We previously identified the histone methylase EZH2 as a protective factor and principal regulator of transcriptional changes in rodent dentate granule cells after status epilepticus (SE).
We wished to discern the mechanism by which EZH2 upregulation confers protection in epilepsy in an effort to identify novel therapeutic targets.
Methods: We utilized novel bioinformatic approaches to mine RNAseq profiles of hippocampi from naïve or epileptic EZH2 conditional knockout (EZH2nKO) mice. We also mined bulk and single cell transcriptomic data from human temporal lobectomies as well as 2 rodent epilepsy models. MAGIC analysis was integrated with single cell transcriptomic data to discern the master regulators that drive large scale gene changes in epilepsy across all major neuronal and non-neuronal cell types.
Ontological analysis was performed across cell types to obtain heuristics describing global gene changes in epilepsy.
Predictions were tested in vivo using biochemical and molecular biological techniques to assess gene changes and alterations in protein levels in mouse models of status epilepticus. Flurothyl seizure threshold testing and video EEG were performed to assess seizure threshold and burden, respectively.
Results: We report here that EZH2 protein is potently induced in neurons after seizures induced by pilocarpine or kainate.
Upon conditional knockout of EZH2 in neurons, we observe a robust reduction in flurothyl seizure threshold acutely post-SE in the absence of threshold changes in naïve mice; this is followed by exacerbated epileptic phenotypes in the chronic period. Network and systems-based approaches highlight increased EZH2 activity in almost every brain cell type.
The suppression of epileptogenesis and slowed disease progression caused by EZH2 are associated with repression of the JAK1 gene and subsequent suppression of STAT3 in hippocampal neurons. Pharmacological inhibition of JAK1 with the orally available, FDA-approved drug CP690550 (Tofacitinib) virtually eliminates behavioral and electrographic seizures after the onset of epilepsy in a preclinical rodent model of acquired epilepsy.
Conclusions: After seizures EZH2 induction attempts to thwart the activation of a pro-epileptogenic gene network centered around STAT3. Identification of this endogenous protective response to status epilepticus
highlights a critical role for the JAK1 kinase in epilepsy. Testing JAK1 inhibitors in other epilepsy models would be worthwhile. Targeting JAK1 with CP690550 has a profound therapeutic effect on spontaneous, recurrent seizures.
Funding: Supported by CURE (AR), Lily’s Fund (AR), NIH grant 1R01NS108756 (AR, RD) and R01NS105628, R01NS102937, and R21NS120868 (JM).