Hormesis/Adaptive Stress Responses and Aging

毒物兴奋/适应性应激反应和衰老

• 批准号: 8335823
• 负责人: Mark Mattson
• 金额: $ 39.29万
• 依托单位: NATIONAL INSTITUTE ON AGING
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/8335823
• 关键词: Affect; Age; Age-Months; Aging; Alkaline Phosphatase; Amyloid; Animal Model; Antioxidants; Attenuated; Biological Assay; Body Weight decreased; Botanicals; Brain; Brain Injuries; Brain-Derived Neurotrophic Factor; Calmodulin; Capillary Electrophoresis; Cell membrane; Cell model; Cells; Cellular Stress; Cellular Stress Response; Cerebral cortex; Cerebrovascular Disorders; Cerebrum; Cessation of life; Characteristics; Chemical Agents; Chemicals; Chloride Ion; Chlorides; Cognitive; Corpus striatum structure; Cyclic AMP-Responsive DNA-Binding Protein; DNA Damage; DNA Repair; DNA lesion; DNA-(apurinic or apyrimidinic site) lyase; Diet; Disease; Dose; Elderly; Electroconvulsive Shock; Electroconvulsive Therapy; Electrons; Energy Intake; Energy Metabolism; Environment; Environmental Risk Factor; Enzymes; Evolution; Exhibits; Exposure to; Fasting; Fibroblast Growth Factor 2; Food; Functional disorder; GRP78 gene; Genes; Glutamate Receptor; Glutamates; Heat-Shock Proteins 70; Hippocampus (Brain); Human; Huntington Disease; Impairment; Inflammatory; Inherited; Injury; Insecta; Insecticides; Intervention; Ischemic Brain Injury; Ischemic Stroke; Learning; Measures; Mediating; Membrane; Memory; Messenger RNA; Metabolic; Metals; Middle Cerebral Artery Occlusion; Mitochondria; Molecular; Molecular Chaperones; Motor; Mus; Mutant Strains Mice; Mutation; NQO1 gene; Nerve Degeneration; Neurodegenerative Disorders; Neurologic; Neurons; Neurotransmitters; Nuclear; Organism; Outcome; Oxidation-Reduction; Oxidative Stress; Pathology; Pathway interactions; Permeability; Pesticides; Phosphorylation; Physiological; Phytochemical; Placebos; Plants; Prevalence; Process; Production; Protein Binding; Proteins; RNA Interference; Reactive Oxygen Species; Receptor Activation; Recycling; Reperfusion Therapy; Reporter; Resistance; Response Elements; Risk Factors; Rodent; Running; Signal Pathway; Stress; Symptoms; Synapses; System; Technology; Therapeutic; Tissue Sample; Toxic effect; Ubiquinone; Up-Regulation; Water; Work; age related; base; biological adaptation to stress; biological systems; brain cell; brain tissue; chelation; cytochrome b5 reductase; cytokine; dietary restriction; enzyme activity; fighting; functional disability; functional outcomes; hazard; heme oxygenase-1; human Huntingtin protein; human SOD2 protein; improved; improved functioning; intravenous administration; kinase inhibitor; male; microchip; middle age; mimetics; mortality; mouse model; mutant; neuroblastoma cell; neurotrophic factor; novel; novel strategies; obesity risk; overexpression; oxidative DNA damage; oxidative damage; peptide A; plumbagin; polyglutamine; post stroke; presenilin-1; prevent; promoter; receptor coupling; repaired; response; stressor; tau mutation

Age and excessive energy intake/obesity are risk factors for cerebrovascular disease, but it is not known if and how these factors affect the extent of brain damage and outcome in ischemic stroke. We therefore determined the interactions of age and energy intake on the outcome of ischemic brain injury, and elucidated the underlying mechanisms. We utilized a novel microchip-based immunoaffinity capillary electrophoresis technology to measure a panel of neurotrophic factors, cytokines and cellular stress resistance proteins in brain tissue samples from young, middle age and old mice that had been maintained on control or energy restricted diets prior to middle cerebral artery occlusion and reperfusion (I/R). Mortality from focal ischemic stroke was increased with advancing age and reduced by an intermittent fasting (IF) diet. Brain damage and functional impairment were reduced by IF in young and middle age mice, but not in old mice. The basal and post-stroke levels of neurotrophic factors (BDNF and bFGF), protein chaperones (HSP70 and GRP78) and the antioxidant enzyme HO-1 were decreased, while levels of inflammatory cytokines were increased in the cerebral cortex and striatum of old mice compared to younger mice. IF coordinately increased levels of protective proteins and decreases inflammatory cytokines in young, but not in old mice. Reduction in dietary energy intake differentially modulates neurotrophic and inflammatory pathways to protect neurons against ischemic injury, and these beneficial effects of IF are compromised during aging resulting in increased brain damage and poorer functional outcome. In another study we developed a bioassay to screen a panel of botanical insecticides to identify those that activate adaptive stress responses in neurons at subtoxic doses. Many phytochemicals function as noxious agents that protect plants against insects and other damaging organisms. However, at subtoxic doses the same phytochemicals may activate adaptive cellular stress response pathways that can protect cells against a variety of adverse conditions. We screened a panel of botanical pesticides using cultured human and rodent neural cell models, and identified plumbagin as a potent activator of the nuclear factor E2-related factor 2 (Nrf2)/ antioxidant response element (ARE) pathway. Subtoxic concentrations of plumbagin increase nuclear localization and transcriptional activity of Nrf2 and induce the expression of the Nrf2/ARE-dependent gene heme oxygenase 1 (HO-1) in human neuroblastoma cells. Plumbagin specifically activates the Nrf2/ARE pathway in primary cortical neurons from ARE-human placental alkaline phosphatase (hPAP) reporter mice. The activation of the ARE and the induction of HO-1 are abolished by RNA interference-mediated knockdown of Nrf2 expression. Exposure of neuroblastoma cells and primary cortical neurons to plumbagin provides protection against subsequent oxidative and metabolic insults. The induction of HO-1 and the neuroprotective effects of plumbagin involve the PI3K/Akt signaling pathway upstream of Nrf2 activation. Intravenous administration of plumbagin significantly reduces the amount of brain damage and ameliorates associated neurological deficits in a mouse model of focal ischemic stroke. Our findings establish precedence for the identification and characterization of neuroprotective phytochemicals based upon their ability to activate adaptive cellular stress response pathways. Glutamate, the major excitatory neurotransmitter in the brain, activates receptors coupled to membrane depolarization and Ca(2+) influx that mediates functional responses of neurons including processes such as learning and memory. Here we show that reversible nuclear oxidative DNA damage occurs in cerebral cortical neurons in response to transient glutamate receptor activation using non-toxic physiological levels of glutamate. This DNA damage was prevented by intracellular Ca(2+) chelation, the mitochondrial superoxide dismutase mimetic MnTMPyP (Mn-5,10,15,20-tetra(4-pyridyl)-21H,23H-porphine chloride tetrakis(methochloride)), and blockade of the permeability transition pore. The repair of glutamate-induced DNA damage was associated with increased DNA repair activity and increased mRNA and protein levels of apurinic endonuclease 1 (APE1). APE1 knockdown induced accumulation of oxidative DNA damage after glutamate treatment, suggesting that APE1 is a key repair protein for glutamate-induced DNA damage. A cAMP-response element-binding protein (CREB) binding sequence is present in the Ape1 gene (encodes APE1 protein) promoter and treatment of neurons with a Ca(2+)/calmodulin-dependent kinase inhibitor (KN-93) blocked the ability of glutamate to induce CREB phosphorylation and APE1 expression. Selective depletion of CREB using RNA interference prevented glutamate-induced up-regulation of APE1. Thus, glutamate receptor stimulation triggers Ca(2+)- and mitochondrial reactive oxygen species-mediated DNA damage that is then rapidly repaired by a mechanism involving Ca(2+)-induced, CREB-mediated APE1 expression. Our findings reveal a previously unknown ability of neurons to efficiently repair oxidative DNA lesions after transient activation of glutamate receptors. Membrane-associated oxidative stress has been implicated in the synaptic dysfunction and neuronal degeneration that occurs in AD, but the underlying mechanisms are unknown. Enzymes of the plasma membrane redox system (PMRS) provide electrons for energy metabolism and recycling of antioxidants. Here, we show that activities of several PMRS enzymes are selectively decreased in plasma membranes from the hippocampus and cerebral cortex of 3xTgAD mice, an animal model of AD. Our results that indicate the decreased PMRS enzyme activities are associated with decreased levels of coenzyme Q(10) and increased levels of oxidative stress markers. Neurons overexpressing the PMRS enzymes (NQO1 or cytochrome b5 reductase) exhibit increased resistance to amyloid β-peptide (Aβ). If and to what extent Aβ is the cause of the impaired PMRS enzymes in the 3xTgAD mice is unknown. Because these mice also express mutant tau and presenilin-1, it is possible that one or more of the PMRS could be adversely affected by these mutations. The impairment of the PMRS in an animal model of AD, and the ability of PMRS enzyme activities to protect neurons against Aβ-toxicity, suggest enhancement PMRS function as a novel approach for protecting neurons against oxidative damage in AD and related disorders. Huntington's disease (HD) is an inherited neurodegenerative disorder caused by expanded polyglutamine repeats in the huntingtin (Htt) protein. Because electroconvulsive shock (ECS) can stimulate the production of brain-derived neurotrophic factor (BDNF) and protect neurons against stress, we determined whether ECS treatment would modify the disease process and provide a therapeutic benefit in a mouse model of HD. ECS (50 mA for 0.2 s) or sham treatment was administered once weekly to male N171-82Q Htt mutant mice beginning at 2 months of age. Endpoints measured included motor function, striatal and cortical pathology, and levels of protein chaperones and BDNF. ECS treatment delayed the onset of motor symptoms and body weight loss and extended the survival of HD mice. Striatal neurodegeneration was attenuated and levels of protein chaperones (Hsp70 and Hsp40) and BDNF were elevated in striatal neurons of ECS-treated compared with sham-treated HD mice. Our findings demonstrate that ECS can increase the resistance of neurons to mutant Htt resulting in improved functional outcome and extended survival. The potential of ECS as an intervention in subjects that inherit the mutant Htt gene merits further consideration.

年龄和能量摄入过多/肥胖是脑血管疾病的危险因素，但尚不清楚这些因素是否以及如何影响缺血性中风的脑损伤程度和结果。 因此，我们确定了年龄和能量摄入对缺血性脑损伤结果的相互作用，并阐明了潜在的机制。 我们利用一种新型的基于微芯片的免疫亲和毛细管电泳技术来测量年轻、中年和老年小鼠脑组织样本中的一组神经营养因子、细胞因子和细胞应激蛋白，这些小鼠在大脑中动脉闭塞和再灌注（I/R）之前一直保持控制或能量限制饮食。局灶性缺血性中风的死亡率随着年龄的增长而增加，而间歇性禁食（IF）饮食则可降低死亡率。 IF 可以减少年轻和中年小鼠的脑损伤和功能障碍，但不能减少老年小鼠的脑损伤和功能障碍。与年轻小鼠相比，老年小鼠大脑皮层和纹状体神经营养因子（BDNF和bFGF）、蛋白伴侣（HSP70和GRP78）和抗氧化酶HO-1的基础和中风后水平降低，而炎症细胞因子水平升高。 IF 可以协调地增加年轻小鼠的保护蛋白水平并减少炎症细胞因子，但在年老小鼠中则不然。 膳食能量摄入的减少会差异性地调节神经营养和炎症途径，以保护神经元免受缺血性损伤，而间歇性间歇性的这些有益作用在衰老过程中会受到损害，导致脑损伤增加和功能结果较差。 在另一项研究中，我们开发了一种生物测定法来筛选一组植物杀虫剂，以确定那些在亚毒剂量下激活神经元适应性应激反应的杀虫剂。许多植物化学物质充当有毒物质，保护植物免受昆虫和其他有害生物的侵害。 然而，在亚毒性剂量下，相同的植物化学物质可能会激活适应性细胞应激反应途径，从而保护细胞免受各种不利条件的影响。 我们使用培养的人类和啮齿动物神经细胞模型筛选了一组植物农药，并确定白花丹素是核因子 E2 相关因子 2 (Nrf2)/抗氧化反应元件 (ARE) 途径的有效激活剂。 亚毒性浓度的白花丹素可增加 Nrf2 的核定位和转录活性，并诱导人神经母细胞瘤细胞中 Nrf2/ARE 依赖性基因血红素加氧酶 1 (HO-1) 的表达。 白花丹素特异性激活 ARE-人胎盘碱性磷酸酶 (hPAP) 报告小鼠原代皮质神经元中的 Nrf2/ARE 通路。 RNA 干扰介导的 Nrf2 表达敲低可消除 ARE 的激活和 HO-1 的诱导。 将神经母细胞瘤细胞和初级皮质神经元暴露于白花丹素中可以防止随后的氧化和代谢损伤。 HO-1 的诱导和白花丹素的神经保护作用涉及 Nrf2 激活上游的 PI3K/Akt 信号通路。 静脉注射白花丹素可显着减少局灶性缺血性中风小鼠模型的脑损伤量并改善相关的神经功能缺损。 我们的研究结果根据神经保护性植物化学物质激活适应性细胞应激反应途径的能力，为神经保护性植物化学物质的识别和表征奠定了优先地位。 谷氨酸是大脑中主要的兴奋性神经递质，激活与膜去极化和 Ca(2+) 流入相关的受体，介导神经元的功能反应，包括学习和记忆等过程。在这里，我们展示了大脑皮层神经元中发生可逆的核氧化 DNA 损伤，以响应使用无毒生理水平的谷氨酸的短暂谷氨酸受体激活。这种 DNA 损伤可通过细胞内 Ca(2+) 螯合、线粒体超氧化物歧化酶模拟物 MnTMPyP（Mn-5,10,15,20-四（4-吡啶基）-21H,23H-氯化卟吩四（甲氯））以及堵塞通透性转换孔来防止。谷氨酸诱导的 DNA 损伤的修复与 DNA 修复活性的增加以及脱嘌呤核酸内切酶 1 (APE1) 的 mRNA 和蛋白质水平的增加有关。谷氨酸处理后，APE1 敲除诱导氧化 DNA 损伤的积累，这表明 APE1 是谷氨酸诱导的 DNA 损伤的关键修复蛋白。 cAMP 反应元件结合蛋白 (CREB) 结合序列存在于 Ape1 基因（编码 APE1 蛋白）启动子中，用 Ca(2+)/钙调蛋白依赖性激酶抑制剂 (KN-93) 处理神经元可阻断谷氨酸诱导 CREB ​​磷酸化和 APE1 表达的能力。使用 RNA 干扰选择性耗尽 CREB ​​可阻止谷氨酸诱导的 APE1 上调。因此，谷氨酸受体刺激会触发 Ca(2+) 和线粒体活性氧介导的 DNA 损伤，然后通过涉及 Ca(2+) 诱导、CREB ​​介导的 APE1 表达的机制快速修复。我们的研究结果揭示了神经元在谷氨酸受体短暂激活后有效修复氧化 DNA 损伤的先前未知的能力。 膜相关的氧化应激与 AD 中发生的突触功能障碍和神经元变性有关，但其潜在机制尚不清楚。质膜氧化还原系统（PMRS）的酶为能量代谢和抗氧化剂的回收提供电子。在这里，我们发现 3xTgAD 小鼠（一种 AD 动物模型）的海马和大脑皮层质膜中的几种 PMRS 酶的活性选择性降低。我们的结果表明 PMRS 酶活性降低与辅酶 Q(10) 水平降低和氧化应激标记物水平升高相关。过度表达 PMRS 酶（NQO1 或细胞色素 b5 还原酶）的神经元表现出对淀粉样蛋白 β-肽 (Aβ) 的抵抗力增强。 Aβ 是否以及在多大程度上是 3xTgAD 小鼠 PMRS 酶受损的原因尚不清楚。由于这些小鼠也表达突变 tau 和早老素-1，因此一种或多种 PMRS 可能会受到这些突变的不利影响。 AD 动物模型中 PMRS 的损伤，以及 PMRS 酶活性保护神经元免受 Aβ 毒性的能力，表明增强 PMRS 功能是保护神经元免受 AD 和相关疾病氧化损伤的新方法。 亨廷顿病 (HD) 是一种遗传性神经退行性疾病，由亨廷顿 (Htt) 蛋白中的聚谷氨酰胺重复序列扩展引起。 由于电休克 (ECS) 可以刺激脑源性神经营养因子 (BDNF) 的产生并保护神经元免受应激，因此我们确定 ECS 治疗是否会改变疾病进程并在 HD 小鼠模型中提供治疗益处。从 2 个月大开始，对雄性 N171-82Q Htt 突变小鼠每周进行一次 ECS（50 mA，0.2 秒）或假治疗。测量的终点包括运动功能、纹状体和皮质病理学以及蛋白伴侣和 BDNF 的水平。 ECS 治疗延迟了运动症状和体重减轻的发生，并延长了 HD 小鼠的生存期。与假处理的 HD 小鼠相比，ECS 处理的纹状体神经元中纹状体神经变性减弱，蛋白伴侣（Hsp70 和 Hsp40）和 BDNF 水平升高。我们的研究结果表明，ECS 可以增加神经元对突变 Htt 的抵抗力，从而改善功能结果并延长生存期。 ECS 作为对遗传突变 Htt 基因的受试者进行干预的潜力值得进一步考虑。