Biological and clinical significance of tTG and isopeptide in AD

tTG 和异肽在 AD 中的生物学和临床意义

• 批准号: 7530370
• 负责人: DENGSHUN WANG
• 金额: $ 18.93万
• 依托单位: UNIVERSITY OF WISCONSIN-MADISON
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-08-01 至 2010-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7530370
• 关键词: Age; Alzheimer' s Disease; Alzheimer' s disease risk; Amyloid; Amyloid beta-Protein; Applications Grants; Autopsy; Biological; Brain; Brain region; Cessation of life; Chronic; Clinic; Clinical; Cognition; Cognitive; Data; Development; Disease; Event; Extracellular Protein; Human; Impaired cognition; Inflammation; Injury; Ischemia; Lead; Measures; Messenger RNA; Methods; Molecular; Neurofibrillary Tangles; Neurons; Occipital lobe; Parkinson Disease; Pathogenesis; Patients; Peptides; Performance; Presenile Alzheimer Dementia; Prevention; Preventive; Process; Production; Proteins; Psyche structure; Public Health; Reagent; Religion and Spirituality; Risk Factors; Role; Sampling; Senile Plaques; Staging; Stress; Structure; Testing; Therapeutic; Tissues; Transglutaminases; Trauma; Traumatic Brain Injury; abstracting; alpha synuclein; base; brain tissue; clinically significant; crosslink; design; familial Alzheimer disease; genetic risk factor; gray matter; link protein; mild neurocognitive impairment; neurofilament; neuron loss; neuropsychological; normal aging; polymerization; prospective; synuclein; tau Proteins

DESCRIPTION (provided by applicant): Biological and clinical significance of tTG and isopeptide in AD Abstract: Extensive protein crosslinkings and aggregation is one of the most important molecular events associated with the pathogenesis of Alzheimer's disease (AD). During AD development, intra- and extracellular proteins are cross-linked, leading to neuronal loss and progressive decline in cognition. Identifing substrate(s) for declined cognition is important not only for eventually solving the mystery of pathogenic mechanism of AD, but also for designing effective therapeutic reagents for the prevention and treatment of AD. Because tissue transglutaminase (tTG) catalyzes the cross-linking of a spectrum of critical proteins including tau, beta-amyloid, neurofilament and alpha-synuclein that are major components of neurofibrillary tangles or neuritic plaques in AD brains, we hypothesize that increased tTG and/or tTG enzymatic activity may initiate protein cross- linking, and the accumulation of cross-linked protein measured by the level of iso-peptide may be closely correlated with the declining mental status of AD patients during the pathogenesis. To test this hypothesis, we propose three Specific Aims: 1. To study the temporal and regional levels of tTG as a function of the development of AD. The mRNA, protein and enzymatic activity of tTG will be measured in cortical gray matter from multiple brain regions including frontal, temporal, pariteal and occipital lobes of postmortem brains from AD, mild cognitive impairment (MCI) and age-matched normal controls (NCI). A group of young normal brains and a group of Parkinson's disease (PD) brains will also be included in this study as controls. AD, MCI, NCI and PD brain samples will be provided from the Brain Bank of prospective longitudinal Religious Order Study using quantitative immunochemical methods. Brain samples of non-aged normal controls (NANC) will be provided by UWHC/VAH and Mayo Clinic Jacksonville Brain Banks. 2. To study changes of isopeptide that is the major product of tTG activity during the AD pathogenesis. Levels of isopeptide from the same panel of samples used in Aim 1 will be quantified with immunochemical methods. 3. To characterize the status of isopeptide and its relationship to clinical neuropsychological performance with the emphasis on the "normal" aging cases and MCI cases. tTG protein, enzymatic activity, iso-peptide level and relevant clinical cognitive or neuropathological parameters will be correlated respectively to explore if accumulation of iso-peptide, presumably due to transglutaminase activity in human brains is an important contributing factor to progressive cognitive declining. If the data obtained from this R21 proposal support our major hypothesis, we will formulate a R01 application to characterize the major substrate(s) that harbor isopeptide. Because the major substrates with isopeptide may vary depending upon the pathogenic stages of AD, some major substrates in the early stage of the disease may be gradually replaced by others in the later stage. Identification of these substrates, especially in the early stages will provide important information regarding AD pathogenesis and help to design preventive and therapeutic reagents for this devastating disease. PUBLIC HEALTH RELEVANCE: This grant application intends to investigate the clinical and biological effects of tissue transglutaminase (tTG) and the accumulation of its product, isopeptides, on the decline of mental status during the pathogenesis of AD in a group of patients collected from Religious Order Study. This will be first systemic study to investigate the relationship of tTg and its product-isopeptides and the cognitive status during the development of AD. The positive data obtained from this R21 project will lead to a new R01 project that will characterize the major substrate(s) that harbor isopeptides in the postmortem human brains. Identification of these substrates, especially in the early stages will provide important information regarding AD pathogenesis and help to design preventive and therapeutic reagents for the disease.

描述（由申请人提供）：tTG和异肽在AD中的生物学和临床意义摘要：广泛的蛋白质交联和聚集是与阿尔茨海默病（AD）发病机制相关的最重要的分子事件之一。在AD发展过程中，细胞内和细胞外蛋白质交联，导致神经元损失和认知进行性下降。识别认知功能下降的底物不仅对最终解决AD的致病机制之谜，而且对设计有效的治疗药物预防和治疗AD具有重要意义。因为组织转氨酶（tTG）催化一系列关键蛋白质的交联，包括tau、β-淀粉样蛋白、神经丝和α-突触核蛋白，它们是AD脑中神经元缠结或神经炎斑块的主要组分，我们假设增加的tTG和/或tTG酶活性可以引发蛋白质交联，以异肽水平衡量的交联蛋白的积累可能与AD患者发病过程中精神状态的下降密切相关。为了验证这一假设，我们提出了三个具体目标：1。研究tTG的时间和区域水平作为AD发展的函数。将在来自AD、轻度认知障碍（MCI）和年龄匹配的正常对照（NCI）的死后脑的多个脑区域（包括额叶、颞叶、顶叶和枕叶）的皮质灰质中测量tTG的mRNA、蛋白质和酶活性。一组年轻的正常大脑和一组帕金森病（PD）大脑也将作为对照纳入本研究。AD、MCI、NCI和PD脑样本将使用定量免疫化学方法从前瞻性纵向宗教秩序研究的脑库中提供。未老化正常对照（NANC）的脑样本将由UWHC/VAH和马约诊所杰克逊维尔脑库提供。2.目的：研究阿尔茨海默病发病过程中tTG活性的主要产物--异肽的变化。将采用免疫化学方法定量目标1中使用的同一组样品的异肽水平。3.目的：探讨异肽的状态及其与临床神经心理学表现的关系，重点是“正常”衰老病例和MCI病例。将分别将tTG蛋白、酶活性、异肽水平和相关临床认知或神经病理学参数相关联，以探索可能由于人脑中转氨酶活性引起的异肽积累是否是进行性认知下降的重要促成因素。如果从R21提案中获得的数据支持我们的主要假设，我们将制定R 01应用程序来表征含有异肽的主要底物。由于异肽的主要底物可根据AD的致病阶段而变化，因此疾病早期的一些主要底物可在后期逐渐被其他底物取代。这些底物的鉴定，特别是在早期阶段，将提供有关AD发病机制的重要信息，并有助于设计这种毁灭性疾病的预防和治疗试剂。公共卫生相关性：本基金申请旨在研究从宗教秩序研究中收集的一组患者中，组织转氨酶（tTG）及其产物异肽的积累对AD发病过程中精神状态下降的临床和生物学影响。这将是首次系统研究tTg及其产物--异肽与AD发生发展过程中认知功能状态的关系。从该R21项目中获得的阳性数据将导致新的R 01项目，该项目将表征死后人脑中含有异肽的主要底物。这些底物的鉴定，特别是在早期阶段，将提供关于AD发病机制的重要信息，并有助于设计预防和治疗该疾病的试剂。