Abstracts

Rationale: Identifying treatments that prevent epileptogenesis is an unmet need. Epileptogenesis involves DNA damage, apoptosis, and inflammation, features also relevant to the cellular senescence program and present following a traumatic brain injury (TBI). 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 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) therapy on seizure burden and behavioral comorbidities in a PTE mouse model.


Methods: 3-4m 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 to assay object and spatial memory and anxiety, common behavioral phenotypes associated with PTE. After behavioral testing, at 3.5m after injury, telemeters were implanted, and EEGs were recorded continuously for 2 weeks. Following EEG recording, mice were tested with a chemoconvulsant challenge (pentylenetetrazole-PTZ) 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 was performed blinded.


Results: Mice given a CCI displayed a robust seizure phenotype, with 65% exhibiting electrographic seizures. Interestingly, 88% of female mice and only 42% of male mice displayed a seizure over the monitoring period. DQ-treated CCI mice have significantly fewer SCs and more PV+ interneurons compared to their vehicle-treated counterparts. Analysis of the elevated plus maze, novel location test, and Barnes Maze is ongoing. Finally, DQ-treated mice have a significantly longer latency to reach motor seizures and tonic-clonic seizures when challenged with PTZ.


Conclusions: This study assesses the use of senolytic therapy in a translationally-compelling context, PTE. Our study, in agreement with others, finds a robust seizure phenotype 4-6months after injury, which may be mediated by sex (1). While DQ does reduce SC burden and ameliorate PV interneuron loss in the PTE mouse mode, more work is needed to understand the mechanisms of epileptogenesis in PTE and the role SCs play therein.


1. Golub and Reddy. Experimental neurology vol. 348 (2022): 113946.




Funding: HT94252410139, R21NS125552-01, NIH NIGMS T32 GM142520