Hormesis/Adaptive Stress Responses and Aging

毒物兴奋/适应性应激反应和衰老

• 批准号: 8931513
• 负责人: Mark Mattson
• 金额: $ 54.67万
• 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/8931513
• 关键词: 1-Phosphatidylinositol 3-Kinase; Adult; Affect; Aging; Alkaline Phosphatase; Alzheimer' s Disease; Antioxidants; Attenuated; Biological Assay; Botanicals; Brain; Brain Injuries; Brain region; Brain-Derived Neurotrophic Factor; Caloric Restriction; Cell Survival; Cell model; Cells; Cellular Stress Response; Cerebral cortex; Cerebrum; Cessation of life; Characteristics; Chemical Agents; Chemicals; Cognitive; Corpus striatum structure; Cyclic AMP-Responsive DNA-Binding Protein; DARPP 32; DNA; DNA Damage; DNA Repair; DNA Repair Enzymes; DNA Repair Pathway; Deacetylase; Deacetylation; Development; Disease; Disease model; Dose; Energy Metabolism; Environment; Environmental Risk Factor; Enzymes; Evolution; Excision; Exercise; Exhibits; Experimental Models; Exposure to; Food; Functional disorder; Genes; Glutamates; Growth; Hippocampus (Brain); Human; Huntington Disease; Injury; Insecta; Insecticides; Ischemic Stroke; Learning; Lesion; Mediating; Mediator of activation protein; Memory; Metabolic; Metals; Molecular; Mus; Naphthoquinones; Nerve Degeneration; Neurodegenerative Disorders; Neurologic; Neuronal Dysfunction; Neurons; Neurotrophic Tyrosine Kinase Receptor Type 2; Nuclear; Organism; Parkinson Disease; Pathway interactions; Pesticides; Phosphotransferases; Phytochemical; Plants; Prevalence; Process; RNA Interference; Reporter; Resistance; Response Elements; Rodent; Role; Running; Signal Pathway; Signal Transduction; Synaptic plasticity; Toxic effect; Water; Work; age related; base; biological adaptation to stress; biological systems; brain cell; cerebral atrophy; coping; endonuclease; excitotoxicity; fighting; hazard; heme oxygenase-1; human FOXO3A protein; improved functioning; inhibitor/antagonist; intravenous administration; motor function improvement; mouse model; mutant; neuroblastoma cell; neuroprotection; novel; novel strategies; overexpression; oxidative DNA damage; phosphoprotein 32; plumbagin; prevent; response; small hairpin RNA; stressor

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. We found that overexpression of sirtuin 1 (Sirt1), a mediator of the beneficial metabolic effects of calorie restriction, protects neurons against mutant HTT toxicity, whereas reduction of Sirt1 exacerbates mutant HTT toxicity. Overexpression of Sirt1 improves motor function, reduces brain atrophy and attenuates mutant-HTT-mediated metabolic abnormalities in Huntington's disease mice. Further mechanistic studies suggested that Sirt1 prevents the mutant-HTT-induced decline in brain-derived neurotrophic factor (BDNF) concentrations and the signaling of its receptor, TrkB, and restores dopamine- and cAMP-regulated phosphoprotein, 32 kDa (DARPP32) concentrations in the striatum. Sirt1 deacetylase activity is required for Sirt1-mediated neuroprotection in Huntington's disease cell models. Notably, we show that mutant HTT interacts with Sirt1 and inhibitsSirt1 deacetylase activity, which results in hyperacetylation of Sirt1 substrates such as forkhead box O3A (Foxo3a), thereby inhibiting its pro-survival function. Overexpression of Sirt1 counteracts the mutant-HTT-induced deacetylase deficit, enhances the deacetylation of Foxo3a and facilitates cell survival. These findings show a neuroprotective role for Sirt1 in mammalian Huntington's disease models and open new avenues for the development of neuroprotective strategies in Huntington's disease. Nuclear factor E2-related factor 2 (Nrf2)/antioxidant response element (ARE) pathway is an important cellular stress response pathway involved in neuroprotection. We previously screened several natural phytochemicals and identified plumbagin as a novel activator of the Nrf2/ARE pathway that can protect neurons against ischemic injury. Here we extended our studies to natural and synthetic derivatives of plumbagin. We found that 5,8-dimethoxy-1,4-naphthoquinone (naphthazarin) is a potent activator of the Nrf2/ARE pathway, up-regulates the expression of Nrf2-driven genes in primary neuronal and glial cultures, and protects neurons against glutamate-induced excitotoxicity. Brain-derived neurotrophic factor (BDNF) promotes the survival and growth of neurons during brain development and mediates activity-dependent synaptic plasticity and associated learning and memory in the adult. BDNF levels are reduced in brain regions affected in Alzheimer's, Parkinson's, and Huntington's diseases, and elevation of BDNF levels can ameliorate neuronal dysfunction and degeneration in experimental models of these diseases. Because neurons accumulate oxidative lesions in their DNA during normal activity and in neurodegenerative disorders, we determined whether and how BDNF affects the ability of neurons to cope with oxidative DNA damage. We found that BDNF protects cerebral cortical neurons against oxidative DNA damage-induced death by a mechanism involving enhanced DNA repair. BDNF stimulates DNA repair by activating cyclic AMP response element-binding protein (CREB), which, in turn, induces the expression of apurinic/apyrimidinic endonuclease 1 (APE1), a key enzyme in the base excision DNA repair pathway. Suppression of either APE1 or TrkB by RNA interference abolishes the ability of BDNF to protect neurons against oxidized DNA damage-induced death. The ability of BDNF to activate CREB and upregulate APE1 expression is abolished by shRNA of TrkB as well as inhibitors of TrkB, PI3 kinase, and Akt kinase. Voluntary running wheel exercise significantly increases levels of BDNF, activates CREB, and upregulates APE1 in the cerebral cortex and hippocampus of mice, suggesting a novel mechanism whereby exercise may protect neurons from oxidative DNA damage. Our findings reveal a previously unknown ability of BDNF to enhance DNA repair by inducing the expression of the DNA repair enzyme APE1. Nuclear factor E2-related factor 2 (Nrf2)/antioxidant response element (ARE) pathway is an important cellular stress response pathway involved in neuroprotection. We previously screened several natural phytochemicals and identified plumbagin as a novel activator of the Nrf2/ARE pathway that can protect neurons against ischemic injury. Here we extended our studies to natural and synthetic derivatives of plumbagin. We found that 5,8-dimethoxy-1,4-naphthoquinone (naphthazarin) is a potent activator of the Nrf2/ARE pathway, up-regulates the expression of Nrf2-driven genes in primary neuronal and glial cultures, and protects neurons against glutamate-induced excitotoxicity.

我们开发了一个生物测定法，以筛选一组植物杀虫剂，以鉴定那些激活下毒性剂量神经元中适应性应激反应的人。许多植物化学物质是保护植物免受昆虫和其他破坏生物的有害剂的作用。 然而，在无毒剂量下，相同的植物化学物质可能会激活适应性的细胞应激反应途径，该途径可以保护细胞免受各种不良条件的影响。 我们使用培养的人类和啮齿动物神经细胞模型筛选了植物农药板，并将铅铅制鉴定为核因子E2相关因子2（NRF2）/抗氧化剂反应元件（AS）途径的有效激活剂。 铅pin的下毒性浓度增加了NRF2的核定位和转录活性，并诱导NRF2/依赖性基因血红素氧酶1（HO-1）在人神经母细胞瘤细胞中的表达。 Plumbagin特异性地激活来自人类胎盘碱性碱性磷酸酶（HPAP）记者小鼠的原代皮质神经元中的NRF2/途径。 通过RNA干扰介导的NRF2表达敲低，将其激活和HO-1的诱导消除。 神经母细胞瘤细胞和原发性皮质神经元暴露于铅垂蛋白可保护，以防止随后的氧化和代谢损伤。 HO-1的诱导和铅笔的神经保护作用涉及NRF2激活上游的PI3K/AKT信号通路。 静脉注射铅铅蛋白的静脉内施用可显着减少脑部缺血性中风的小鼠模型中脑损伤的量，并改善相关的神经缺陷。 我们的发现基于激活适应性细胞应激反应途径的能力来鉴定和表征神经保护性植物化学物质的优先级。 我们发现，Sirtuin 1（SIRT1）的过表达是卡路里限制的有益代谢作用的介体，可保护神经元免受突变的HTT HTT毒性，而SIRT1降低SIRT1加剧突变体HTT HTT毒性。 SIRT1的过表达可改善运动功能，减少脑萎缩，并减轻亨廷顿病小鼠中突变体HTT介导的代谢异常。进一步的机械研究表明，SIRT1可防止突变体HTT诱导的脑衍生神经营养因子（BDNF）浓度下降及其受体TRKB的信号传导，并恢复了谱图中32 kDa（darpp32）浓度的多巴胺和cAMP调节磷酸蛋白。 SIRT1脱乙酰基酶活性是SIRT1介导的亨廷顿病细胞模型中的神经保护需要的。值得注意的是，我们表明突变型HTT与SIRT1相互作用并抑制SIRT1脱乙酰基酶活性，从而导致SIRT1底物（例如Forkhead Box O3a（FoxO3A））的过度乙酰化，从而抑制其促卵巢功能。 SIRT1的过表达抵消了突变-HTT诱导的脱乙酰基酶缺损，增强了FOXO3A的脱乙酰基化并促进细胞存活。这些发现显示了SIRT1在哺乳动物亨廷顿氏病模型中的神经保护作用，并开放了开发亨廷顿氏病神经保护策略的新途径。 核因子E2相关因子2（NRF2）/抗氧化剂响应元件（AS）途径是参与神经保护的重要细胞应力反应途径。我们先前筛选了几种天然植物化学物质，并确定了铅铅制是NRF2/是可以保护神经元免受缺血性损伤的途径的新型激活剂。在这里，我们将研究扩展到了铅垂的天然和合成衍生物。我们发现5,8-二甲氧基-1,4-萘醌（萘氮蛋白）是NRF2/是途径的有效激活剂，在原发性神经元和神经胶质培养物中上调了NRF2驱动的基因的表达，可在神经元中保护神经元免受粘液氨酸酯诱导的兴奋性兴奋性。 脑衍生的神经营养因子（BDNF）促进了脑发育过程中神经元的存活和生长，并介导了成人活动依赖性突触可塑性以及相关的学习和记忆。在阿尔茨海默氏症，帕金森氏症和亨廷顿疾病中影响的大脑区域的BDNF水平降低，而BDNF水平的升高可以改善这些疾病实验模型的神经元功能障碍和变性。由于神经元在正常活性期间和神经退行性疾病中会在其DNA中积累氧化病变，因此我们确定BDNF是否以及如何影响神经元应对氧化DNA损伤的能力。我们发现BDNF通过涉及增强的DNA修复的机制来保护脑皮质神经元免受氧化性DNA损伤诱导的死亡。 BDNF通过激活环状AMP响应元件结合蛋白（CREB）刺激DNA修复，从而诱导源自磷灰膜/apyrimidinic核酸内核酸酶1（APE1）的表达，这是碱基切除DNA修复途径中的关键酶。通过RNA干扰抑制APE1或TRKB可以废除BDNF保护神经元免受氧化DNA损伤诱导的死亡的能力。 BDNF激活CREB和上调APE1表达的能力被TR​​KB的shRNA以及TRKB，PI3激酶和Akt激酶的抑制剂所取消。自愿跑步轮运动可显着增加BDNF的水平，激活CREB并上调小鼠的大脑皮层和海马中的APE1，这表明一种新型的机制可以保护神经元免受氧化DNA损伤。我们的发现表明，通过诱导DNA修复酶APE1的表达，BDNF以前未知的能力增强了DNA修复。 核因子E2相关因子2（NRF2）/抗氧化剂响应元件（AS）途径是参与神经保护的重要细胞应力反应途径。我们先前筛选了几种天然植物化学物质，并确定了铅铅制是NRF2/是可以保护神经元免受缺血性损伤的途径的新型激活剂。在这里，我们将研究扩展到了铅垂的天然和合成衍生物。我们发现5,8-二甲氧基-1,4-萘醌（萘氮蛋白）是NRF2/是途径的有效激活剂，在原发性神经元和神经胶质培养物中上调了NRF2驱动的基因的表达，可在神经元中保护神经元免受粘液氨酸酯诱导的兴奋性兴奋性。