Investigation of glial and neuronal regenerative mechanisms in epilepsy utilising a surgical and post mortem tissue collection

癫痫是一种常见的疾病，影响着英国50多万人。在大约三分之一的患者中，发作性癫痫不能单靠药物控制。在这些患者中，手术治疗是成功的。多年来，从这些患者身上切除的脑组织已经被研究过，并发现了各种各样的异常或病变。正是通过这些研究，我们才能够了解可能促进癫痫的常见脑细胞异常（包括神经元和神经胶质细胞）以及如何预防这种异常。一种常见的病变被称为皮质发育不良，在接受手术的儿童和成人以及死于癫痫并将其大脑捐献给研究的患者的脑组织中都可以看到。“皮质发育不良”指的是灰质（或皮层）的一个区域组织异常，由神经元和神经胶质细胞组成，这些细胞具有不成熟的特性。皮层发育不良有几种亚型，其中一些可能是在出生前（在大脑发育期间）获得的，而另一些则与大脑的第二种异常“相关”，如海马硬化症（海马体瘢痕）和低级别肿瘤，通常是在生命的头几年获得的。越来越清楚的是，这些“相关的”发育不良是出生和发育后成熟大脑中持续的局部重组的结果。与15年前的科学观点相反，现在已经完全确定，大脑中含有大量被称为祖细胞的细胞，能够在出生后形成新的神经元和神经胶质。这个过程受到严格控制，我们开始了解是什么在调节它，以及这些祖细胞在修复和记忆形成方面的正常功能。从癫痫动物模型中我们知道，癫痫发作对祖细胞的数量及其增殖方式有直接影响。从我们和其他人迄今为止所做的工作来看，似乎很有可能是祖细胞的异常活动导致了一些（如果不是全部的话）发育不良。我们的目标是研究接受过癫痫手术治疗的患者以及有长期癫痫病史的患者死后组织中的这些细胞。我们将比较这些细胞在不同类型的发育不良、大脑的不同区域（所谓的窝藏这些细胞的“壁龛”）和不同年龄组之间的特性。通过用祖细胞的特定标记标记这些细胞，我们可以收集到这些细胞的数量与没有癫痫的人的脑组织相比是如何变化的信息，它们分裂的频率，以及它们是否成熟为神经元或神经胶质细胞。我们还将比较死前多次癫痫发作的患者和控制良好的癫痫患者之间的祖细胞数量，以便直接评估癫痫发作如何影响这些细胞类型。通过观察引起癫痫发作的大脑区域和不引起癫痫发作的大脑区域，我们将能够在手术中（而不是死后）获得的组织中做同样的事情。同样，将在癫痫患者中研究祖细胞，这些患者在疾病过程中出现记忆和智力障碍，以调查它们对这一过程的贡献。最后，我们已经开始在癫痫组织样本上使用一种叫做蛋白质组学的技术，这种技术可以在一次实验中从一个样本中识别出数千种蛋白质。我们已经开始识别异常存在的新蛋白质，这些蛋白质可能通过影响祖细胞功能障碍和癫痫而导致发育不良。我们的发现将对祖细胞如何导致发育不良，以及重要的是如何操纵这一过程从而导致治疗，甚至可能预防癫痫提供新的见解。

Epilepsy is a common disorder affecting more than half a million people in the UK. In about a third of patients, the episodic seizures cannot be controlled by drugs alone. In a proportion of these patients, surgical treatment is successful. The brain tissues removed from these patients over the years have been studied and a wide variety of abnormalities or lesions noted. It is through such studies that we have been able to understand common abnormalities of brain cells (including neurones and glia) that could promote epilepsy and how this could be prevented. One common lesion is called cortical dysplasia which can be seen in both children and adults undergoing surgery as well as in brain tissue from patients who have died from epilepsy and donated their brain for research. 'Cortical dysplasia' refers to a region of grey matter (or cortex) which is abnormally organised and composed of neurones and glial cells which have immature properties. There are several subtypes of cortical dysplasia, some of which are likely to have been acquired before birth (during brain development) and others which are 'associated' with a second abnormality in the brain, such as hippocampal sclerosis (scarring of the hippocampus) and low grade tumours that are often acquired during the first years of life. It is becoming clear that these 'associated' dysplasia are a result ongoing local re-organisation in the mature brain, after birth and development. It is now well established, contrary to the scientific belief held only 15 years ago, that the brain contains pools of cells called progenitor cells, capable of forming new neurons and glia well after birth. This process is tightly controlled and we are beginning to understand what regulates it, as well as the normal functions of these progenitor cells, in aspects of repair and memory formation. From animal models in epilepsy we know that seizures have a direct effect on the number of progenitor cells and how they proliferate. From the work we and others have carried out to date, it seems highly likely that abnormal activity of progenitor cells underlies some, if not all, dysplasias. Our goal is to study these cells in patients who have undergone surgical treatment for their epilepsy as well as in post mortem tissues from patients with a long history of epilepsy. We will compare the properties of these cells between different types of dysplasia, in different regions of the brain (so called 'niches' known to harbor these cells) and in different age groups. By labeling these cells with specific markers for progenitor cells, we can gather information on how the numbers of these cells are changed in comparison to brain tissue from people who did not have epilepsy, how frequently they are dividing and if they are maturing into neurones or glial cells. We will also compare progenitor cell numbers between patients known to have many seizures before they died, and patients with well-controlled epilepsy in order to directly assess how seizures could influence these cell types. We will be able to do the same in tissue taken at operation (rather than after death), by looking at areas of brain that cause seizures to those areas that do not cause seizures. Similarly, progenitor cells will be studied in patients with epilepsy who have developed memory and impairment of intellect during the course of their disease, to investigate their contribution to this process. Lastly, we have started a using a technique called proteomics on epilepsy tissues samples which allows potentially thousands of proteins to be identified from one specimen in one experiment. We have already started to identify novel proteins which are abnormally present and that could be causing dysplasia, by influencing progenitor cell dysfunction and epilepsy.Our findings will give new insights into how progenitor cells lead to dysplasias and importantly how this process might be manipulated leading to treatment, and perhaps prevention of epilepsy.