A Systems Approach Delivers A Functional Microrna Catalog And Expanded Targets For Seizure Suppression In Temporal Lobe Epilepsy

Temporal lobe epilepsy is the most common drug-resistant form of epilepsy in adults. The reorganization of neural networks and the gene expression landscape underlying pathophysiologic network behavior in brain structures such as the hippocampus has been suggested to be controlled, in part, by microRNAs. To systemati-cally assess their significance, we sequenced Argonaute-loaded microRNAs to define functionally engaged microRNAs in the hip-pocampus of three different animal models in two species and at six time points between the initial precipitating insult through to the establishment of chronic epilepsy. We then selected commonly up-regulated microRNAs for a functional in vivo therapeutic screen using oligonucleotide inhibitors. Argonaute sequencing generated 1.44 billion small RNA reads of which up to 82% were microRNAs, with over 400 unique microRNAs detected per model. Approximately half of the detected microRNAs were dysregulated in each epilepsy model. We prioritized commonly up-regulated microRNAs that were fully conserved in humans and designed custom antisense oligonu-cleotides for these candidate targets. Antiseizure phenotypes were observed upon knockdown of miR-10a-5p, miR-21a-5p, and miR-142a-5p and electrophysiological analyses indicated broad safety of this approach. Combined inhibition of these three microRNAs reduced spontaneous seizures in epileptic mice. Proteomic data, RNA sequenc-ing, and pathway analysis on predicted and validated targets of these microRNAs implicated derepressed TGF-beta signaling as a shared seizure-modifying mechanism. Correspondingly, inhibition of TGF-beta signaling occluded the antiseizure effects of the antagomirs. To-gether, these results identify shared, dysregulated, and functionally active microRNAs during the pathogenesis of epilepsy which repre-sent therapeutic antiseizure targets.