Background: Traumatic brain injury (TBI) remains a significant risk factor for post-traumatic epilepsy (PTE). The pathophysiological mechanisms underlying the injury-induced epileptogenesis are under investigation. The dentate gyrus—a structure that is highly susceptible to injury—has been implicated in the evolution of seizure development. Methods: Utilizing the murine unilateral focal control cortical impact (CCI) injury, we evaluated seizure onset using 24/7 EEG video analysis at 2–4 months post-injury. Cellular changes in the dentate gyrus and hilus of the hippocampus were quantified by unbiased stereology and Imaris image analysis to evaluate Prox1-positive cell migration, astrocyte branching, and morphology, as well as neuronal loss at four months post-injury. Isolation of region-specific astrocytes and RNA-Seq were performed to determine differential gene expression in animals that developed post-traumatic epilepsy (PTE+) vs. those animals that did not (PTE−), which may be associated with epileptogenesis. Results: CCI injury resulted in 37% PTE incidence, which increased with injury severity and hippocampal damage. Histological assessments uncovered a significant loss of hilar interneurons that coincided with aberrant migration of Prox1-positive granule cells and reduced astroglial branching in PTE+ compared to PTE- mice. We uniquely identified Cst3 as a PTE+-specific gene signature in astrocytes across all brain regions, which showed increased astroglial expression in the PTE+ hilus. Conclusions: These findings suggest that epileptogenesis may emerge following TBI due to distinct aberrant cellular remodeling events and key molecular changes in the dentate gyrus of the hippocampus.

Background: Traumatic brain injury (TBI) remains a significant risk factor for post-traumatic epilepsy (PTE). The pathophysiological mechanisms underlying the injury-induced epileptogenesis are under under investigation. The dentate gyrus, a structure highly susceptible to injury, and has been implicated in the evolution of seizure development. Methods: Utilizing the murine unilateral focal control cortical impact (CCI) injury, we evaluated seizure onset using 24/7 EEG video analysis at 2-4 months post-injury. Cellular changes in the dentate gyrus and hilus of the hippocampus were quantified by non-biased stereology and Imaris image analysis to evaluate Prox1-positive cell migration, astrocyte branching and morphology, as well as neuronal loss at four months post-injury. Isolation of region-specific astrocytes and RNA-seq was performed to determine differential gene expression in PTE+ vs. PTE- that may comport with the epileptogenic process. Results: CCI injury resulted in 37% PTE+-incidence, which increased with injury severity and hippocampal damage. Histological assessments uncovered a significant loss of hilar interneurons that coincided with aberrant migration of Prox1-positive granule cells and reduced astroglial branching in PTE+ compared to PTE- mice. We uniquely identified Cst3 as a PTE+-specific gene signature in astrocytes across all brain regions. Conclusions: These findings suggest that epileptogenesis may emerge following TBI due to distinct aberrant cellular remodeling events and key molecular changes in the dentate gyrus of the hippocampus.

ObjectivePost‐traumatic epilepsy (PTE) is an acquired epilepsy that develops in the months or years following a traumatic brain injury (TBI) and can lead to substantial personal, financial, and societal burden. To date, PTE is rarely curable; current treatments are partially effective and often accompanied by adverse side effects. While research on PTE has expanded significantly in the last several years, there remain numerous challenges to identifying effective prevention and treatment strategies. In this paper, we describe advances from the CURE Epilepsy PTE Initiative, including its implementation and the emphasis on team science.MethodsThe CURE Epilepsy PTE Initiative funded six research teams to link preclinical and clinical studies to engage in the validation of experimental models, characterization of pathophysiology and biological pathways, and identification of risk factors associated with PTE. Three teams had projects with both a preclinical and a clinical component; these teams focused on: targeting the epileptogenic effects of subarachnoid blood, exploring the neuropathological mechanisms of epileptogenesis, and defining the role of extracellular matrix injury. Two teams undertook entirely preclinical projects: exploring the role of vascular injury, gliosis, and neurogenesis as drivers for PTE, and identifying genetic, proteomic, metabolomic, and microRNA biosignatures to improve the prediction of PTE. One team's project was entirely clinical and investigated genetic and protein biomarkers to improve the prediction of PTE.ResultsIn addition to scientific discoveries including characterization of a variety of animal models and progress towards the understanding of biological underpinnings and biomarkers for PTE, significant programmatic and personnel‐related processes were incorporated, including standardized, rigorous policies and procedures to ensure quality and accountability between and within groups.SignificanceWe propose CURE Epilepsy's team science approach as an effective way to bring together a diverse set of investigators to explore biological mechanisms that may lead to cures for the epilepsies.