Abstracts

Rationale: Brain-derived neurotrophic factor (BDNF) is a neurotrophin that regulates a wide variety of cell signaling pathways including pro- survival and cell death machinery in a receptor-specific manner. Previous studies in rat have demonstrated an increase in BDNF expression after status epilelepticus (SE), that activates inducible cAMP early repressor (ICER) transcription via Signal Transducer and Activator of Transcription 3 (STAT3) activation. ICER activation mediates a downstream decrease in the expression of the alpha 1 subunit of the GABAA receptor in the hippocampal dentate gyrus of rat. Recent studies have shown that modulation of p75 neurotrophin receptor prevents BDNF-induced activation of the JAK/STAT pathway in rat cultured hippocampal neurons, suggesting that proBDNF may play a critical role. The goal of this project is to investigate the relative contribution of proBDNF signaling to the JAK/STAT pathway after SE through the use BDNF-tagged transgenic C57BL/6J mice.Methods: A repetitive low-dose pilocarpine regimen was compared to a single high-dose regimen on the basis of efficacy of SE induction and mortality. Using these criteria, the low-dose regimen proved to be more efficacious for C57BL/6J mice. The mice were sacrificed at one and three hours and levels of phospho-STAT3 protein were probed via Western blot.Results: The single high-dose regimen was ineffective in producing SE across a large dosing scheme. A repetitive low-dose regimen was able to induce SE in 80% of C57BL/6J mice in a pilot study of 10 mice. Phospho-STAT3 levels in hippocampus were markedly increased after induction of SE at one and three hours. Conclusions: The following studies demonstrate the ability to induce status epilepticus in the C57BL/6J mouse by using an adapted repetitive low-dose pilocarpine regimen that resulted in elevated levels of pSTAT3 protein at one and three hours after induction of SE as seen in previous rat studies. Studies are currently under way utilizing immunohistochemistry to determine the cell-specific expression of pSTAT3 in glia and neurons. These studies provide the foundation to further investigate the role of proBDNF signaling in epileptogenesis.