The Effect of Senolytic Therapy in a Mouse Model of Post-Traumatic Epilepsy

Abstract ID 101688 Poster Board 135 While there are dozens of anti-seizure medications available for patients with epilepsy, up to one third of patients experience seizures refractory to treatment. Identifying treatments that prevent epileptogenesis is an unmet need. Epileptogenesis involves DNA damage, apoptosis, and inflammation, features also relevant to the cellular senescence program. Senescent cells (SCs) arise in response to extreme stress or injury, leading to a decline in normal functioning and increased inflammation. Ongoing studies from our group show that both genetic and pharmacologic ablation of SCs normalizes spatial memory and reduces seizure burden in the status epilepticus mouse model. However, no studies have looked at the contribution of SCs in the development of post-traumatic epilepsy (PTE), where recurrent seizures develop following a traumatic brain injury. (TBI) This model is translationally compelling because the inciting epileptogenic event (a TBI) is often brought to clinical attention, making prophylactic anti-epileptogenic drugs a clinically viable strategy to prevent PTE. Here, we investigate the effects of dasatinib and quercetin (DQ) combination therapy on seizure burden and behavioral comorbidities in the PTE mouse model. 3-4mo old p16-TdTomato reporter mice on a C57Bl/6 background were given a controlled cortical impact (CCI) or sham surgery with the following parameters: 5.25m/s velocity, 2mm depth, 0.1sec dwell time, 3.5mm diameter impounder tip. Mice were then randomly assigned to receive either DQ or a vehicle injection IP once per week for the duration of the study. 2 months after injury, mice were tested in a battery of behavioral tests in order to assay object and spatial memory and anxiety, common behavioral phenotypes associated with PTE. After behavioral testing, at 3.5 months after injury, telemeters were implanted in the mice, and EEGs were recorded continuously for 2 weeks with synchronous video. Following EEG recording, mice were tested with a chemoconvulsant challenge (pentylenetetrazole-PTZ, a GABA-a antagonist) as a secondary measure of seizure-protective effects. Mice were then euthanized, and their brains were fixed for histology to confirm SC ablation and assess neurodegeneration. A similar number of animals were used from each sex. Analysis of behavior, EEGs, and histology were all performed blinded. Mice given a CCI displayed a robust seizure phenotype, with a majority of animals exhibiting electrographic seizures. DQ-treated CCI mice have significantly fewer SCs compared to their vehicle-treated counterparts. SC ablation appears to reduce behavioral deficits in the open field test, elevated plus maze, and novel location test, although at the time of writing we lack the power to claim so conclusively. Finally, DQ-treated mice have a significantly longer latency to reach motor seizures and tonic-clonic seizures when challenged with PTZ. This study assesses the use of senolytic therapy in a translationally-compelling context, PTE. While DQ does reduce SC burden in the PTE mouse model, more work is needed to understand the mechanisms of epileptogenesis in PTE and the role SCs play therein. Therefore, further work will explore the effect of DQ on rescuing CCI-mediated deficits in long-term potentiation and the effect of DQ on the transcriptome of CCI-injured mice. R21NS125552-01, NIH NIGMS T32 GM142520