Abstracts

Rationale: Wnt signaling is an intracellular pathway well-studied in normal development and misregulated in cancers; it has recently been implicated in synaptic plasticity, but remains unexplored in the context of epilepsy. Our proposal investigates whether or not Wnt signaling is modulated following Status Epilepticus (SE). The overarching goal is modulating Wnt signaling as a novel treatment strategy for altering epileptogenesis at early time points immediately following SE. In the canonical Wnt signaling, alteration of ?-catenin protein is key. In absence of Wnt signals, Glycogen Synthase Kinase3?,(GSK3?), is a constitutively active kinase, which phosphoylates the N-terminal region of cytosolic ?-catenin, leading to its ubiquitination and proteosome-mediated degradation. However, when Wnt is activated,these proteolytic processes are suppressed due to inhibition of GSK3? activity. Stabilized ?-catenin is translocated into the nuclei where it associates with the transcription factor Tcf/Lef and activates gene transcription. Methods: We utilized adult male Sprague Dawley Rats and age matched controls for this study. Status Epilepticus (SE) was induced using kainic acid 10 mg/kg I.P. and seizures scored according to a modified Racine Scale. Animals were sacrificed at 3, 12, 24 hours, 3 and 7 days to establish a time course for Wnt alteration. Results: Our preliminary data suggested a modest increase in total ?-catenin at 1 hour following SE. We added to this finding by examining additional time points. Cytosol ?-catenin n = 3-6 animals. 3hr1.18 0.22 12hr0.98 0.13 24hr0.93 0.07 3d1.06 0.19 7d1.16 0.10 Nuclear?-Catenin 3hr0.82 0.23 12hr0.79 0.15 24hr0.93 0.13 3d1.19 0.37 7d1.08 0.10 Conclusions: 1) There is not a significant increase in nuclear ?-catenin following SE. 2) We are exploring explanations for this finding including the following possibilities: 2a) Changes in ?-catenin are spatially specific (eg: CA1 vs CA3 vs Dentate Gyrus). We will subsegment these hippocampal regions to explore alterations in beta catenin levels. 2b) GSK3? is upstream of ?-catenin and it's phosphorylation of ?-catenin renders ?-catenin inactive. We are exploring parallel changes in GSK3? in conjunction to changes in ?-catenin.