Neuroprotective microRNA pathways

神经保护性 microRNA 通路

• 批准号: 8292793
• 负责人: Scott E Counts
• 金额: $ 19.13万
• 依托单位: RUSH UNIVERSITY MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-07-01 至 2013-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8292793
• 关键词: Address; Affect; Alzheimer' s Disease; Amyloid; Area; Autopsy; Behavior; Biochemical; Biological Markers; Brain; Brodmann' s area; Cell physiology; Cells; Cellular Stress; Cerebellum; Cognitive; Complex; Consultations; Data; Databases; Deacetylase; Dementia; Development; Disease; Disease Progression; Down-Regulation; Energy Metabolism; Enzymes; Family; Family member; Fluorescent in Situ Hybridization; Functional RNA; Gene Expression Regulation; Generations; Genes; Harvest; Human; Immunoblotting; Immunohistochemistry; Immunoprecipitation; Impaired cognition; In Vitro; Inferior; Knowledge; Mediating; Messenger RNA; MicroRNAs; Modeling; Modification; Molecular; Neurodegenerative Disorders; Neurologic; Neurons; Onset of illness; Pathogenesis; Pathway interactions; Physiological; Physiology; Pilot Projects; Process; Proteins; RNA; Regulation; Role; Sampling; Senile Plaques; Small Interfering RNA; Specificity; Staging; Synaptic plasticity; Temporal Lobe; Testing; Therapeutic; Tissue Harvesting; Tissues; Toxic effect; Transcript; Up-Regulation; amyloid pathology; base; beta-site APP cleaving enzyme 1; biological adaptation to stress; clinical Diagnosis; drug discovery; forkhead protein; frontal lobe; human tissue; in vitro Assay; infancy; inhibitor/antagonist; innovation; insight; internal control; knock-down; mRNA Stability; mild neurocognitive impairment; neurogenesis; neuroprotection; new therapeutic target; novel; protein expression; research study; response; secretase

DESCRIPTION (provided by applicant): The presence of small non-coding microRNAs (miRNAs) which regulate mRNA stability has become increasingly appreciated as a critical factor in fine-tuning specific neuronal protein levels to mediate diverse brain functions. This widespread influence of miRNA regulation on neuronal physiology suggests that perturbations in miRNA function are involved in the pathogenesis of complex neurodegenerative disorders such as Alzheimer's disease (AD). However, despite initial insights that miRNAs contribute to amyloid pathology during disease progression, the field remains in its infancy and must expand to focus on identifying key multifarious miRNA network changes occurring during the onset of AD which will drive novel therapeutic targets. In particular, whether miRNA networks are dysregulated in the brains of people in the prodromal stages of AD such as amnestic mild cognitive impairment (aMCI) and the extent to which these changes have physiologic consequences for AD progression remain underexplored. To this end, our preliminary microarray and quantitative PCR (qPCR) studies discovered two families of miRNAs, miR-212/132 and miR-23a/b, that were down-regulated in the frontal cortex of aMCI subjects compared to controls. Human miRNA databases revealed that the down-regulation of either miR-212/132 or miR-23a/b was predicted to up-regulate two targets that interact to mediate neuroprotective cell stress responses, the deacetylase sirtuin 1 (sirt1) and the forkhead transcription factor foxo3a; pilot qPCR studies using the same frontal cortex samples revealed that both sirt1 and foxo3a mRNA levels were higher in aMCI compared to controls. Given the relatively delayed involvement of frontal cortex in AD pathogenesis and the ability of this region to respond to the onset of dementia by neuronal reorganization, these data suggest that miRNA-mediated up-regulation of the sirt1/foxo3a pathway represents a compensatory neuroprotective response to mounting disease. In fact, qPCR analysis performed on temporal cortex, an area affected early in the progression of AD, showed no changes in miR-212, miR-23a, sirt1, or foxo3a transcripts in the aMCI subjects. Moreover, pilot in vitro mechanistic studies showed that the coordinated down-regulation of miR-212 and miR-23a increased Sirt1 and Foxo3a protein expression and provided neuroprotection from ¿-amyloid toxicity in human neuronal cells. Hence, our preliminary data suggest that we have uncovered a novel miRNA-mediated neuroprotective pathway activated during prodromal AD. This proposal will test this hypothesis using human tissue molecular, biochemical, and histochemical approaches as well as mechanistic pathway modeling in human neurons. These studies may reveal new insights into gene regulation pathways leading to innovative therapeutic avenues for modifying AD progression. PUBLIC HEALTH RELEVANCE: MicroRNA (miRNA) regulation of neuronal gene networks affects a wide variety of complex cellular processes; hence, multifarious miRNA function could influence the progression of neurodegenerative disorders such as Alzheimer's disease (AD). Based on our exciting pilot studies, this proposal will test the extent to which coordinated down-regulation of two related miRNA families activates a neuroprotective pathway during the prodromal stages of AD. Our findings will validate the novel proposition that innate compensatory miRNA-mediated pathways are activated early in AD progression. A greater understanding of these miRNA pathways during the onset of AD will reveal innovative targets for drug discovery, biomarker development, and disease modification.

描述（由申请人提供）：调节 mRNA 稳定性的小非编码 microRNA (miRNA) 的存在已越来越被认为是微调特定神经元蛋白质水平以介导不同大脑功能的关键因素。 miRNA 调节对神经元生理学的广泛影响表明 miRNA 功能的扰动与阿尔茨海默病 (AD) 等复杂的神经退行性疾病的发病机制有关。 然而，尽管初步认识到 miRNA 在疾病进展过程中会导致淀粉样蛋白病理学，但该领域仍处于起步阶段，必须扩展以专注于识别 AD 发病期间发生的关键的多种 miRNA 网络变化，这将推动新的治疗靶点。特别是，处于 AD 前驱阶段（例如遗忘性轻度认知障碍 (aMCI)）的人大脑中 miRNA 网络是否失调，以及这些变化对 AD 进展产生生理影响的程度仍有待探索。为此，我们的初步微阵列和定量 PCR (qPCR) 研究发现了两个 miRNA 家族：miR-212/132 和 miR-23a/b，与对照组相比，它们在 aMCI 受试者的额叶皮层中表达下调。人类 miRNA 数据库显示，miR-212/132 或 miR-23a/b 的下调预计会上调两个相互作用介导神经保护性细胞应激反应的靶标，即脱乙酰酶 Sirtuin 1 (sirt1) 和叉头转录因子 Foxo3a；使用相同额叶皮层样本的初步 qPCR 研究表明，与对照组相比，aMCI 中的 Sirt1 和 Foxo3a mRNA 水平较高。鉴于额叶皮层在 AD 发病机制中相对延迟的参与以及该区域通过神经元重组对痴呆症发作作出反应的能力，这些数据表明 miRNA 介导的 Sirt1/foxo3a 通路的上调代表了对日益严重的疾病的补偿性神经保护反应。事实上，对颞叶皮层（AD 进展早期受影响的区域）进行的 qPCR 分析显示，aMCI 受试者中 miR-212、miR-23a、sirt1 或 Foxo3a 转录本没有变化。 此外，初步体外机制研究表明，miR-212 和 miR-23a 的协调下调可增加 Sirt1 和 Foxo3a 蛋白的表达，并提供神经保护，防止人类神经元细胞中的 β-淀粉样蛋白毒性。 因此，我们的初步数据表明，我们发现了一种新的 miRNA 介导的 AD 前驱期激活的神经保护途径。该提案将使用人体组织分子、生物化学和组织化学方法以及人类神经元的机械通路模型来测试这一假设。这些研究可能揭示基因调控途径的新见解，从而为改变 AD 进展提供创新的治疗途径。 公共健康相关性：神经元基因网络的 MicroRNA (miRNA) 调节影响多种复杂的细胞过程；因此，多种 miRNA 功能可能影响阿尔茨海默病 (AD) 等神经退行性疾病的进展。基于我们令人兴奋的试点研究，该提案将测试两个相关 miRNA 家族的协调下调在 AD 前驱阶段激活神经保护途径的程度。 我们的研究结果将验证先天补偿性 miRNA 介导的通路在 AD 进展早期被激活的新主张。 更好地了解 AD 发病期间的这些 miRNA 通路将揭示药物发现、生物标志物开发和疾病修饰的创新靶点。