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。 我们发现 Sirtuin 1 (Sirt1) 的过度表达（热量限制的有益代谢作用的调节剂）可以保护神经元免受突变 HTT 毒性，而 Sirt1 的减少会加剧突变 HTT 毒性。 Sirt1 的过度表达可改善亨廷顿病小鼠的运动功能、减少脑萎缩并减轻突变 HTT 介导的代谢异常。进一步的机制研究表明，Sirt1 可防止突变体 HTT 诱导的脑源性神经营养因子 (BDNF) 浓度及其受体 TrkB 信号传导的下降，并恢复多巴胺和 cAMP 调节的磷蛋白 32 kDa (DARPP32) 浓度。纹状体。在亨廷顿病细胞模型中，Sirt1 脱乙酰酶活性是 Sirt1 介导的神经保护所必需的。值得注意的是，我们发现突变型 HTT 与 Sirt1 相互作用并抑制 Sirt1 脱乙酰酶活性，从而导致 Sirt1 底物（例如叉头盒 O3A (Foxo3a)）过度乙酰化，从而抑制其促生存功能。 Sirt1 的过度表达可以抵消突变体 HTT 诱导的脱乙酰酶缺陷，增强 Foxo3a 的脱乙酰化并促进细胞存活。这些发现表明 Sirt1 在哺乳动物亨廷顿病模型中具有神经保护作用，并为亨廷顿病神经保护策略的开发开辟了新途径。 核因子E2相关因子2（Nrf2）/抗氧化反应元件（ARE）途径是参与神经保护的重要细胞应激反应途径。我们之前筛选了几种天然植物化学物质，并确定白花丹素是 Nrf2/ARE 通路的新型激活剂，可以保护神经元免受缺血性损伤。在这里，我们将研究扩展到白花丹素的天然和合成衍生物。我们发现 5,8-dimethoxy-1,4-naphthoquinone (naphthazarin) 是 Nrf2/ARE 通路的有效激活剂，上调原代神经元和胶质细胞培养物中 Nrf2 驱动基因的表达，并保护神经元免受谷氨酸的影响引起的兴奋性毒性。 脑源性神经营养因子（BDNF）在大脑发育过程中促进神经元的存活和生长，并介导成人活动依赖性突触可塑性以及相关的学习和记忆。受阿尔茨海默病、帕金森病和亨廷顿病影响的大脑区域的 BDNF 水平降低，而 BDNF 水平的升高可以改善这些疾病的实验模型中的神经元功能障碍和退化。由于神经元在正常活动期间和神经退行性疾病中会在其 DNA 中积累氧化损伤，因此我们确定了 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 通过增强 DNA 修复的机制保护大脑皮层神经元免受氧化 DNA 损伤引起的死亡。 BDNF 通过激活环 AMP 反应元件结合蛋白 (CREB) 刺激 DNA 修复，进而诱导脱嘌呤/脱嘧啶核酸内切酶 1 (APE1) 的表达，APE1 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 会消除 BDNF 保护神​​经元免受氧化 DNA 损伤诱导死亡的能力。 BDNF 激活 CREB ​​和上调 APE1 表达的能力被 TrkB 的 shRNA 以及 TrkB、PI3 激酶和 Akt 激酶的抑制剂消除。自愿跑轮运动显着增加小鼠大脑皮层和海马体中 BDNF 的水平，激活 CREB ​​并上调 APE1，这表明运动可以保护神经元免受氧化 DNA 损伤的新机制。我们的研究结果揭示了 BDNF 通过诱导 DNA 修复酶 APE1 的表达来增强 DNA 修复的先前未知的能力。 核因子E2相关因子2（Nrf2）/抗氧化反应元件（ARE）途径是参与神经保护的重要细胞应激反应途径。我们之前筛选了几种天然植物化学物质，并确定白花丹素是 Nrf2/ARE 通路的新型激活剂，可以保护神经元免受缺血性损伤。在这里，我们将研究扩展到白花丹素的天然和合成衍生物。我们发现 5,8-dimethoxy-1,4-naphthoquinone (naphthazarin) 是 Nrf2/ARE 通路的有效激活剂，上调原代神经元和胶质细胞培养物中 Nrf2 驱动基因的表达，并保护神经元免受谷氨酸的影响引起的兴奋性毒性。