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

• 批准号: 10443534
• 负责人: Keiichiro Susuki
• 金额: $ 34.16万
• 依托单位: WRIGHT STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-08-01 至 2024-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10443534
• 关键词: Action Potentials; Affect; Age; Alzheimer' 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' 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; 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

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 有髓鞘轴突的可兴奋结构域的改变，特别是轴突起始段（AIS）和 兰氏结是包括糖尿病在内的各种神经退行性疾病的关键病理生理学。 AIS长度的缩短已被证明降低神经元的兴奋性，并且还涉及认知功能。 2型糖尿病和阿尔茨海默病的损害。然而，细胞和分子机制， 这些结构域在疾病条件下如何改变仍然知之甚少。这种知识上的关键差距 限制了磁场操纵AIS和节点进行治疗的能力。目前的建议旨在阐明 神经系统病理生理学的重要方面。本申请的总体目标是确定 AIS和淋巴结破坏过程中的关键分子环节。先前的研究和初步数据 这里提供的已经确定了甲基乙二醛（MG）的升高，MG是葡萄糖的高活性副产物 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该过程。核心假设是， 丙酮醛通过钙蛋白酶激活破坏AIS和结蛋白复合物，并抑制神经系统 功能我们将通过三个具体目标来检验这一假设。目的1：检验MG减少的假设 新清除肽的水平将改善db/db小鼠中AIS缩短和认知障碍， 2型糖尿病的一个已建立的模型。目的2：检验MG升高导致AIS/淋巴结的假设 变化，降低神经网络活性（Aim 2A，体外;小鼠皮层神经元培养和多电极 阵列）和认知损害（Aim 2B，体内;全身施用MG或谷胱甘肽酶1抑制剂， 一种在野生型小鼠中使MG解毒的酶）。目的3：检验钙蛋白酶介导的效应的假设 MG对AIS/节点结构、神经网络活性（目的3A，体外;药理学钙蛋白酶抑制）的影响，以及 认知功能（目的3B，C，体内;钙蛋白酶抑制蛋白的遗传操作，钙蛋白酶抑制蛋白是一种特异性内源性抑制剂， 钙蛋白酶）。目的3B将评估钙蛋白酶抑制蛋白中MG增加和钙蛋白酶过度激活的联合作用 Aim 3C将评估过度表达MG和钙蛋白酶的小鼠中增加的MG和钙蛋白酶抑制 钙蛋白酶抑制素这种应用在概念上是创新的，因为我们提出，高架MG的关键目标是 活体神经元AIS和Ranvier结的结构。多电极阵列的创新使用将 确定MG增加和AIS缩短对神经网络功能的影响。拟议研究 是重要的，因为目标的完成将验证MG和钙蛋白酶作为翻译的潜在靶点。 针对共病认知障碍的治疗方法的研究-例如在目标1中测试的新型MG清除剂- 2型糖尿病的危害。这些结果也有可能影响各种神经退行性疾病。 条件，如阿尔茨海默氏症，从而最终提供了一个持续的和强大的影响力的领域。

项目成果

Distinct Changes in Calpain and Calpastatin during PNS Myelination and Demyelination in Rodent Models.

• DOI: 10.3390/ijms232315443
• 发表时间: 2022-12-06
• 期刊: INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
• 影响因子: 5.6
• 作者: Miller, John A. A.;Drouet, Domenica E. E.;Yermakov, Leonid M. M.;Elbasiouny, Mahmoud S. S.;Bensabeur, Fatima Z. Z.;Bottomley, Michael;Susuki, Keiichiro
• 通讯作者: Susuki, Keiichiro