L-aspartate signalling in the brain

课程概述：这个由MRC资助的博士培训伙伴关系(DTP)将尖端分子和分析科学与数据分析中的创新计算方法结合在一起，使学生能够与工业界合作开展重要的应用生物医学研究。这是一个为期4年的课程，第一年包括一系列的教学模块和两个基于实验室的研究项目，这些项目导致了跨学科生物医学研究的硕士学位。前两个学期包括精选的教学模块，使学生能够在多学科的科学中获得坚实的基础。学生们还参加了由学术和行业专家主持的一系列大师课程，这些专家涉及分子、细胞和组织动力学、微生物学和传染病、应用生物医学技术以及人工智能和数据科学等领域。在第三学期和暑期，学生们在他们选择的实验室里进行两个为期十一周的研究项目。项目：L-天冬氨酸被认为是一种兴奋性神经递质，但它作为一种兴奋性神经递质的贡献在很大程度上被认为是对谷氨酸的支持，谷氨酸是一种公认的兴奋性氨基酸神经递质。通过使用一种新型的L-天冬氨酸生物传感器，我们发现，将L-天冬氨酸转化为L-天冬氨酸的胞内酶天冬氨酸合成酶是胞外天冬氨酸的关键决定因素。阻断ASN可导致细胞外L-天冬氨酸在海马脑片内蓄积，并通过NMDA型受体依赖的过程发展成癫痫样活动。人类ASN的突变与小头畸形、认知障碍和慢性癫痫有关。我们的数据表明，这种表型可能是由于L-天冬氨酸的过度积累。本项目将继续我们的研究，包括海马和皮质脑片中L-天冬氨酸释放的机制和环境，ASN的阻断的影响，以及介导L-天冬氨酸从细胞外空间移除的转运体的身份。由于ASN功能缺陷与癫痫有关，因此将在对照组和癫痫小鼠的组织中检测L-天冬氨酸释放。细胞外L-天冬氨酸的积聚通过激活N-甲基-D-天冬氨酸受体而导致癫痫活动的发展。通过使用有效和特定的药理学工具，将确定所涉及的NMDA受体亚型。由于某些N-甲基-D-天冬氨酸受体亚型仅在海马区非常特殊的细胞类型上表达，这一重要步骤将有助于阐明参与L-天冬氨酸诱发癫痫活动的细胞回路。通过了解控制细胞外L-天冬氨酸的分子机制，该项目将为了解其生理作用以及门冬氨酸信号转导障碍如何导致癫痫提供新的见解。

Programme overview:This MRC-funded doctoral training partnership (DTP) brings together cutting-edge molecular and analytical sciences with innovative computational approaches in data analysis to enable students to undertake important applied biomedical research in partnership with industry. This is a 4-year programme whose first year involves a series of taught modules and two laboratory-based research projects that lead to an MSc in Interdisciplinary Biomedical Research. The first two terms consist of a selection of taught modules that allow students to gain a solid grounding in multidisciplinary science. Students also attend a series of masterclasses led by academic and industry experts in areas of molecular, cellular and tissue dynamics, microbiology and infection, applied biomedical technologies and artificial intelligence and data science. During the third and summer terms students conduct two eleven-week research projects in labs of their choice. Project:L-aspartate has been suggested as an excitatory neurotransmitter but, its contribution as an excitatory neurotransmitter has largely been discounted on favour of glutamate, the universally recognised excitatory amino acid neurotransmitter. By using a new biosensor for L-aspartate, we have discovered that the intracellular enzyme, asparagine synthetase (ASNS), which converts L-aspartate to L-asparagine, is a key determinant of extracellular aspartate. Blockade of ASNS leads to accumulation of extracellular L-aspartate and development of seizure-like activity in hippocampal brain slices via an NMDA-receptor dependent process. Human mutations of ASNS are linked to microcephaly, cognitive impairment and chronic epilepsy. Our data suggests that some of this phenotype could be due to excessive accumulation of L-aspartate.This project will continue our study of the mechanisms and circumstances of L-aspartate release in hippocampal and cortical brain slices, the effects of blockade of ASNS, and the identity of the transporters that mediate the removal of L-aspartate from the extracellular space. As defective function of ASNS is linked to epilepsy, L-aspartate release will be examined in tissue from both control and epileptic mice. Accumulation of extracellular L-aspartate results in the development of seizure activity via the NMDA receptor activation. By using potent and specific pharmacological tools, the NMDA receptor subtypes involved will be established. As certain NMDA receptor subtypes are expressed only on very specific cell types in the hippocampus, this important step will help to elucidate the cellular circuitry involved in L-aspartate induced seizure activity. By understanding the molecular mechanisms that control extracellular L-aspartate this project will provide new insight into its physiological actions and how disorders of asparate signalling can lead to epilepsy.