Molecular imaging reveals epileptogenic Ca2+-channel promoter activation in hippocampi of living mice
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Focal epilepsies often originate in the hippocampal formation of the temporal lobe (temporal lobe epilepsy) and are generally acquired after transient brain insults. Such insults induce cellular and structural reorganization processes of the hippocampus, referred to as epileptogenesis that finally convert the brain spontaneous epileptic. Here, we developed a new molecular imaging strategy in a state-of-the-art animal model to provide insights into key epileptogenic mechanisms. Our new approach combines recombinant adeno-associated virus (rAAV) gene delivery with in vivo bioluminescence imaging. rAAV particles harboring the luciferase reporter gene under control of the minimal T type Ca2+-channel subunit Ca V 3.2-promoter were generated and injected stereotaxically in the hippocampal region of mice. Bioluminescent signals, corresponding to Ca V 3.2 promoter activation, were imaged in vivo in the pilocarpine model of status epilepticus (SE). We detected activation of key Ca V 3.2 promoter motifs at 3 and 10 days after SE but not after the onset of chronic seizures. These data suggest Ca V 3.2 promoter activation as novel anti-epileptogenic target. In more general terms, we have established an experimental approach that allows to follow cerebral gene promoter dynamics longitudinally and to correlate this activity to behavioral parameters in the same mice.
KeywordsMolecular neuroimaging Epilepsy Pilocarpine animal model Transcriptional channelopathies T type calcium channel CaV3.2 In vivo bioluminescence imaging
Our work is supported by the Deutsche Forschungsgemeinschaft (SFB 1089 (KvL, SS, AJB), KFO 177 (AJB)), “Unabhängige Forschergruppen in den Neurowissenschaften” (SS), European Science Foundation (EuroEpinomics Consortium (KvL, AJB)), the European Union’s Seventh Framework Program (FP7/2007-2013) under grant agreement no 602102 (EPITARGET; SS, AJB), the Else Kröner-Fresenius Foundation (AJB), German Israeli Foundation (AJB), BONFOR (KvL, AJB, SS), German Center for Neurodegenerative Diseases (DZNE; YW, EMM) and MPG (YW, EMM).
Conflict of interest
The authors declare that they have no conflict of interest.
- Klerk CP, Overmeer RM, Niers TM, Versteeg HH, Richel DJ, Buckle T, Van Noorden CJ, van Tellingen O (2007) Validity of bioluminescence measurements for noninvasive in vivo imaging of tumor load in small animals. Biotechniques 43(7–13):30Google Scholar
- van Loo KM, Schaub C, Pernhorst K, Yaari Y, Beck H, Schoch S, Becker AJ (2012) Transcriptional regulation of T-type calcium channel CaV3.2: bi-directionality by early growth response 1 (Egr1) and repressor element 1 (RE-1) protein-silencing transcription factor (REST). J Biol Chem 287:15489–15501PubMedCentralCrossRefPubMedGoogle Scholar