Disruption of Excitable Axonal Domains by Glucose Metabolite Methylglyoxal

葡萄糖代谢物甲基乙二醛对可兴奋轴突结构域的破坏

基本信息

批准号：
10247444
负责人：
Keiichiro Susuki
金额：
$ 33.05万
依托单位：
WRIGHT STATE UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2019
资助国家：
美国
起止时间：
2019-08-01 至 2023-07-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10247444
关键词：
Action Potentials Affect Age Alzheimer&apos s Disease Axon Behavior Brain Brain Injuries Brain region Calcium Calpain Caspase Characteristics Chronic Corpus Callosum Data Diabetes Mellitus Disease Electron Microscopy Enzymes Functional disorder Glucose Hippocampus (Brain)Immunofluorescence Immunologic Immunofluorescence Microscopy Impaired cognition Impairment In Vitro Injections Knockout Mice Knowledge Lactoylglutathione Lyase Learning Length Link Measures Mediating Mediator of activation protein Metabolic Modeling Molecular Mus Mutant Strains Mice Natural regeneration Nerve Nerve Degeneration Nervous System Physiology Nervous system structure Neural Conduction Neurologic Neurologic Symptoms Neurons Nodal Non-Insulin-Dependent Diabetes Mellitus Optic Nerve Optics Patients Peptides Pharmacology Prefrontal Cortex Process Public Health Pyruvaldehyde Ranvier&apos s Nodes Reporting Research Role Short-Term Memory Signal Transduction Structure Testing Time Transgenic Mice Translational Research Wild Type Mouse calpain inhibitor calpastatin cognitive function comorbidity db/db mouse diabetic genetic manipulation glucose metabolism in vivo inhibitor/antagonist innovation morris water maze multi-electrode arrays nerve conduction study neural network neuronal excitability nodal protein non-diabetic novel prevent protein complex sciatic nerve therapeutic target

项目摘要

Project summary/abstract Alterations in the excitable domains of myelinated axons, specifically the axon initial segment (AIS) and the nodes of Ranvier, are key pathophysiologies in various neurodegenerative conditions, including diabetes. Shortening of AIS length has been shown to lower neuronal excitability, and is also implicated in cognitive impairment in type 2 diabetes and Alzheimer’s disease. However, the cellular and molecular mechanisms of how these domains are altered in disease conditions remain poorly understood. This critical gap in knowledge limits the field’s ability to manipulate the AIS and nodes for treatment. The current proposal seeks to elucidate this important aspect of nervous system pathophysiology. The overall objective of this application is to identify a critical molecular link in the process of AIS and nodal disruption. The prior studies and preliminary data provided here have identified elevations in methylglyoxal (MG), a highly reactive byproduct of glucose metabolism, as a potential mediator for AIS and nodal disruption. These data also support that calpains, calcium-dependent intracellular cysteine proteases, are involved in this process. The central hypothesis is that methylglyoxal disrupts AIS and nodal protein complexes via calpain activation and inhibits nervous system function. We will test this hypothesis via three Specific Aims. Aim 1: Test the hypothesis that reduction of MG levels with novel scavenging peptides will ameliorate AIS shortening and cognitive impairment in db/db mice, an established model for type 2 diabetes. Aim 2: Test the hypothesis that elevated MG causes AIS/node changes, reduced neural network activity (Aim 2A, in vitro; mouse cortical neuron culture and multi-electrode arrays), and cognitive impairment (Aim 2B, in vivo; systemic administration of MG or inhibitor of glyoxalase 1, an enzyme that detoxifies MG, in wild-type mice). Aim 3: Test the hypothesis that calpains mediate the effects of MG on AIS/node structures, neural network activity (Aim 3A, in vitro; pharmacological calpain inhibition), and cognitive function (Aim 3B, C, in vivo; genetic manipulation of calpastatin, a specific endogenous inhibitor of calpains). Aim 3B will assess combined effects of increased MG and calpain over-activation in calpastatin knockout mice; and Aim 3C will assess increased MG and calpain inhibition in mice over-expressing calpastatin. This application is conceptually innovative, as we propose that the key targets of elevated MG are the structures of the AIS and nodes of Ranvier in live neurons. Innovative use of multi-electrode arrays will determine the effects of increased MG and AIS shortening on neural network function. The proposed research is significant, because completion of the aims will validate MG and calpains as potential targets for translational research aimed at treatments – such as the novel MG scavengers tested in Aim 1 – for comorbid cognitive impairment in type 2 diabetes. These results also have potential to impact a wide variety of neurodegenerative conditions, such as Alzheimer’s, thus ultimately providing a sustained and powerful influence on the field.

项目概要/摘要有髓轴突兴奋域的改变，特别是轴突初始段（AIS）和朗飞结是各种神经退行性疾病（包括糖尿病）的关键病理生理学。 AIS 长度的缩短已被证明会降低神经兴奋性，并且还与认知能力有关然而，2 型糖尿病和阿尔茨海默病的细胞和分子机制受到损害。对于这些领域在疾病条件下如何改变仍然知之甚少。限制了该领域操纵 AIS 和节点进行治疗的能力。当前的提案旨在阐明。神经系统病理生理学的这一重要方面本应用的总体目标是确定。 AIS 和节点破坏过程中的关键分子环节。此处提供的内容已确定甲基乙二醛 (MG) 升高，这是一种葡萄糖的高反应性副产品新陈代谢，作为 AIS 和淋巴结破坏的潜在介质，这些数据也支持钙蛋白酶，钙依赖性细胞内半胱氨酸蛋白酶参与了这一过程。核心假设是。甲基乙二醛通过钙蛋白酶激活破坏 AIS 和节点蛋白复合物并抑制神经系统我们将通过三个具体目标来检验这个假设：检验 MG 减少的假设。新型清除肽水平将改善 db/db 小鼠的 AIS 缩短和认知障碍，目标 2：检验 MG 升高导致 AIS/结节的假设。变化，神经网络活动减少（目标 2A，体外；小鼠皮质神经培养和多电极阵列）和认知障碍（目标 2B，体内；全身施用 MG 或乙二醛酶 1 抑制剂，目标 3：检验钙蛋白酶介导作用的假设。 MG 对 AIS/节点结构、神经网络活动（目标 3A，体外；药理钙蛋白酶抑制）以及认知功能（目标 3B、C，体内；钙蛋白酶抑制剂（一种特定的内源性抑制剂）的基因操作目标 3B 将评估 MG 增加和钙蛋白酶过度激活对钙蛋白酶抑制素的综合影响。基因敲除小鼠；Aim 3C 将评估过度表达小鼠中 MG 和钙蛋白酶抑制的增加该应用在概念上是创新的，因为我们提出 MG 升高的关键目标是活体神经元中 AIS 和 Ranvier 节点的结构将创新性地使用多电极阵列。确定增加 MG 和 AIS 缩短对神经网络功能的影响。意义重大，因为目标的完成将验证 MG 和钙蛋白酶作为转化的潜在目标旨在治疗共病认知的研究——例如目标 1 中测试的新型 MG 清除剂这些结果也有可能影响多种神经退行性疾病。阿尔茨海默氏症等疾病，从而最终对该领域产生持续而强大的影响。