Adult Subventricular Zone Gliogenesis in Limbic Epilepsy

描述（申请人提供）：人颞叶癫痫（TLE）在神经元丢失和突触重组的程度上各不相同，但总是以海马“反应性”胶质增生为特征。星形胶质细胞增生长期以来与局灶性癫痫有关，但迄今为止的研究未能确定胶质细胞如何影响TLE的癫痫发作。从癫痫大鼠匹罗卡品处理和从切除的癫痫人颞叶记录的海马星形胶质细胞具有未成熟星形胶质细胞的电生理特征。这一提议将检验癫痫发作诱导异常胶质细胞生成的假设，最终结果是随后癫痫发作的风险增加。 理论上，响应于癫痫发作产生的海马神经胶质细胞可能来自室管膜下区（SVZ）或颗粒下区（SGZ）祖细胞的迁移和分化，来自局部内源性前体细胞或来自重新进入成熟星形胶质细胞的细胞周期。基于申请人先前对对照和癫痫海马中神经胶质细胞特性的研究，本提案将使用逆转录病毒介导的基因转移、电生理学和免疫组织化学技术的组合来研究癫痫诱导的SVZ和SGZ神经胶质细胞生成。我们将在大鼠匹罗卡品边缘癫痫模型中比较SVZ和SGZ衍生的海马胶质细胞生成的时间过程、细胞命运和生理后果。此外，我们将确定在诱导癫痫发作之前局灶性消融SVZ和/或海马祖细胞池的后果。 具体目标1：确定癫痫发作是否诱导祖细胞迁移到海马和随后的胶质细胞分化。 具体目标二：通过电生理学和分子标准确定癫痫发作后产生的胶质细胞是否仍然不成熟。 具体目标3：确定选择性破坏SVZ和海马中的细胞增殖是否影响胶质细胞发育和癫痫发生。

DESCRIPTION (provided by applicant): Human temporal lobe epilepsy (TLE) varies in the degree of neuronal loss and synaptic reorganization, but is always characterized by hippocampal "reactive" gliosis. Astrogliosis has long been associated with focal epilepsy, yet studies to date have failed to establish how glial cells may influence seizures in TLE. Hippocampal astrocytes recorded from epileptic rats treated with the convulsant pilocarpine and from resected epileptic human temporal lobe have electrophysiological features of immature astrocytes. This proposal will test the hypothesis that seizures induce abnormal gliogenesis and the ultimate consequence is that the risk of subsequent seizures increases. Hippocampal glial cells generated in response to seizures could theoretically arise from migration and differentiation of sub-ventricular zone (SVZ) or sub-granular zone (SGZ) progenitor cells, from local endogenous precursor cells or from re-entry into the cell cycle of mature astrocytes. Building on the applicant's previous investigation of glial cell properties in the control and epileptic hippocampus, this proposal will use a combination of retroviral mediated gene transfer, electrophysiological and immunohistochemical techniques to investigate seizure induced SVZ and SGZ gliogenesis. We will compare the time course, cell fate and physiological consequences of SVZ and SGZ derived hippocampal gliogenesis in the rat pilocarpine limbic epilepsy model. In addition, we will determine the consequences of focally ablating the SVZ and/or hippocampus progenitor pool prior to the induction of seizures. Specific Aim 1: To determine whether seizures induce migration of progenitor cells to and subsequent gliogenic differentiation within the hippocampus. Specific Aim 2: To determine whether the glial cells that are generated in response to seizures remain immature, by electrophysiological and molecular criteria. Specific Aim 3: To determine whether selective disruption of cellular proliferation in the SVZ and the hippocampus influences glial development and epileptogenesis.