Transcriptional profiling of dentate granule cells in 4 rat epilepsy models

Global expression profiling of epileptogenesis has been confounded by variability across laboratories, epilepsy models, tissue sampled and experimental platforms, with the result that very few genes demonstrate consistent expression changes. The present study minimizes these confounds by combining Affymetrix microarray datasets from seven laboratories, using three status epilepticus (SE) models of epilepsy in rats (pilocarpine, kainate, self-sustained SE or SSSE) and the rat kindling model. Total RNA was harvested from laser-captured dentate granule cells from 6 rats at three times during the early-to-mid latent phase that precedes epilepsy symptoms in the SE models (1, 3 and 10 days after SE), or 24 hr after the first stage 2, stage 4 and stage 5 seizure in the kindling model. Each epilepsy model was studied in two independent laboratories except SSSE. The initial goals of this study were to a) identify model-independent transcriptional changes in dentate granule cells that could point to novel intervention targets for epileptogenesis, b) characterize the basal transcriptional profile of dentate granule cells, and c) identify genes that have highly variable expression.癫痫发生的全基因表达谱分析常受实验室差异、癫痫模型选择、采样组织类型及实验平台异质性的干扰，导致仅有极少数基因可呈现一致的表达变化。本研究通过整合来自7家实验室的Affymetrix微阵列数据集，并采用3种大鼠癫痫持续状态（status epilepticus, SE）模型（毛果芸香碱、海人酸、自持续癫痫持续状态（self-sustained SE, SSSE））以及大鼠点燃模型，尽可能消除上述混杂因素的影响。本研究从6只大鼠的激光捕获齿状回颗粒细胞中采集总RNA：对于SE模型，采样时点为癫痫症状出现前的早中期潜伏期，即癫痫持续状态造模后1、3、10天；对于点燃模型，采样时点为首次出现2级、4级、5级癫痫发作后的24小时。除SSSE模型外，其余每种癫痫模型均在2家独立实验室中开展研究。本研究的初始目标包括：a）鉴定齿状回颗粒细胞中不依赖于模型的转录改变，以揭示癫痫发生的新型干预靶点；b）解析齿状回颗粒细胞的基础转录谱特征；c）鉴定表达水平存在高度异质性的基因。