Discovery of Novel Molecular Abnormalities Underlying Non-Lesional Focal Epilepsy

描述(由申请人提供)：本提案的目标是探索分子异常--体细胞突变、微生物核酸的存在或两者兼而有之--在非病变局灶性癫痫(NLFE)中的作用。癫痫影响着全球近1%的人口，三分之一的患者对目前可用的抗癫痫药物没有反应。对于这些患者来说，控制癫痫发作的最大希望来自癫痫手术，切除癫痫灶，当可以确定灶的时候。在MRI上明确显示致病病变的患者中，60%-80%的患者手术后癫痫发作消失。在明确的局灶性癫痫患者中，没有可识别的MRI病变，手术治愈较少，从30%到50%不等。我们认为NLFE的问题是一个解决的问题--在MRI上可能看不到异常，但在分子水平上以两种形式中的一种或两种形式存在：1)仅限于大脑的细胞中的体细胞突变；2)微生物的存在，如病毒核酸 酸，这可能会导致分子异常并影响癫痫的发病。有证据表明，体细胞突变在由发育性结构损害引起的癫痫中起作用，但尚未发现在非病变性癫痫中发生体细胞突变。根据在患有内侧颞叶硬化症的颞叶癫痫患者脑组织中检测到HHV6，以及最近在局灶性皮质发育不良区域发现人乳头瘤病毒，已提出病毒感染在癫痫和皮质发育性分子损害中的作用。病毒在NLFE中更广泛的作用尚未得到证明，其他病原体的作用也没有得到证明。我们将调查在接受手术的癫痫患者的癫痫灶中是否存在体细胞突变和微生物核酸，并使用下一代测序方法在切除的脑组织中识别这些分子异常。我们将使用系统生物学方法，整合最先进的术中皮质记录来识别癫痫灶，并与临床、组织病理学和分子序列数据共同登记，从而实现这一点。因此，我们将创建一个具有详细表型数据的NLFE脑组织存储库，这将是此类数据中的第一个。证明癫痫发作可以由躯体突变或感染引起，而不改变大脑的宏观结构，这将改变理解癫痫发生的范式，并可能导致识别新的生物标志物和治疗方法。

DESCRIPTION (provided by applicant): The goal of this proposal is to explore the role of molecular abnormalities-somatic mutation, the presence of microbial nucleic acids, or both--underlying non-lesion focal epilepsy (NLFE). Epilepsy affects nearly 1% of the world's population and 1/3 of patients do not respond to currently available anticonvulsant medications. For these patients the best hope for seizure control comes from epilepsy surgery with resection of the seizure focus, when a focus can be identified. In patients for whom a causative lesion is clearly demonstrable on MRI, 60-80% of patients are seizure-free after surgery. In patients with clear focal epilepsy with no identifiable MRI lesion, surgical cure is less common, ranging from 30-50%. We propose that the problem of NLFE is one of resolution-that the abnormalities may not be visible on MRI but are present at the molecular level, in one or both of two forms: 1) somatic mutation, in cells restricted to brain and 2) the presence of microbial, e.g. viral nucleic acids, which may cause molecular abnormalities and influence epilepsy onset. There is some evidence to suggest that somatic mutation plays a role in epilepsies resulting from developmental structural lesions such as hemimegalencephaly, but somatic mutation has not yet been shown to occur in non-lesion epilepsies. The role of viral infection in epilepsy and developmental molecular lesions of the cortex has been suggested based on the detection of HHV6 in brain tissue from temporal lobe epilepsy patients with mesial temporal sclerosis and with the recent discovery of human papilloma virus in areas of focal cortical dysplasia, a developmental malformation strongly associated with epilepsy. The broader role of viruses in NLFE has not been demonstrated, nor the role of other pathogens. We will investigate whether somatic mutations and microbial nucleic acids are present in the seizure foci of individuals with epilepsy who undergo surgery, using next generation sequencing approaches to identify these molecular abnormalities in resected brain tissue. We will accomplish this using a systems biology approach, integrating state-of-the-art cortical intraoperative recordings to identify the seizure focus, co-registered with clinical, histopathology, and molecular sequence data. We will thereby create a repository of NLFE brain tissue with detailed phenotypic data which will be the first of its kind. Proving that seizures can arise from somatic mutations or infection without altering brain macrostructure would shift the paradigm for understanding epileptogenesis, and could lead to identification of novel biomarkers and treatments.