HIV modulation of BAG3 impacting quality control of Tau in neuronal cells

HIV 对 BAG3 的调节影响神经元细胞中 Tau 的质量控制

• 批准号: 10170194
• 负责人: Kamel Khalili
• 金额: $ 39.63万
• 依托单位: TEMPLE UNIV OF THE COMMONWEALTH
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-09-30 至 2023-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10170194
• 关键词: Affect; Alzheimer' s Disease; Alzheimer' s disease brain; Animal Model; Animals; Apoptosis; Attention; Autophagocytosis; BAG3 gene; Biochemical; Bioenergetics; Brain; CRISPR/Cas technology; Calcium Signaling; Cause of Death; Cell Culture Techniques; Cell physiology; Cells; Clinical Research; Clustered Regularly Interspaced Short Palindromic Repeats; Data; Deposition; Development; Disease; Down-Regulation; Energy Metabolism; Ensure; Environment; Equilibrium; Event; Excision; Generations; Genome; HIV; HIV Infections; HIV Seronegativity; HIV Seropositivity; HIV tat Protein; HIV-1; HIV-associated neurocognitive disorder; Heat-Shock Proteins 70; Homeostasis; In Vitro; Infection; Interruption; Investigation; Laboratories; Life; Light; Mediating; Membrane Potentials; Memory; Microelectrodes; Microtubule-Associated Proteins; Microtubules; Mitochondria; Modeling; Molecular; Molecular Chaperones; Neurodegenerative Disorders; Neurofibrillary Tangles; Neurons; Organelles; Outcome; Outcome Study; Pathogenesis; Pathogenicity; Pathway interactions; Patients; Physiological; Process; Production; Proteins; Quality Control; Risk; Risk Factors; Role; Signal Transduction; Stress; Stress-Induced Protein; System; Thinking; Toxic effect; Transgenic Animals; United States; Up-Regulation; Viral Proteins; Virus; aging brain; antiretroviral therapy; brain tissue; endoplasmic reticulum stress; experimental study; human old age (65+); in vivo; interest; misfolded protein; mitochondrial membrane; mutant; neuron loss; neuronal circuitry; neurotoxic; parkin gene/protein; premature; protein aggregation; proteostasis; small hairpin RNA; tat Protein; tau Proteins; tau aggregation; tau phosphorylation; tau-1; transmission process; treatment effect

PROJECT SUMMARY It is estimated that more than 10% of the 1.1 million HIV positive patients in United States will be over 65 years old in less than ten years, a critical stage in life where the the risk for developing Alzheimer’s disease (AD) increases. Earlier results from clinical studies showed several abnormalities including difficulties with memory, thinking, and reasoning become more common in older HIV positive patients, implying that their risk factors may be elevated when compared with their HIV negative counterparts. This notion brings up the concept that HIV infection, even in patients whose virus is well controlled by antiretroviral therapy (ART), may be more prone to developing neurodegenerative disorders including AD. Considering the inability of ART to effectively suppress expression of viral proteins, including HIV Tat, which is a profoundly neurotoxic protein, we envision a scenario in which, by dysregulating the protein quality control (PQC) pathway, Tat may perturb homeostasis of key proteins associated with the pathogenesis of AD and set the stage for the development of disease. Several data from our and other laboratories support this concept. First, we demonstrated that Tat inhibits expression of BAG3, a co-chaperone/partner of HSP70 that is involved in the removal of dysfunctional and obsolete organelles including mitochondria through a process called mitophagy, and participates in autophagy and clearance of damaged and misfolded proteins by the protein quality control (PQC) pathway. Second, activation of BAG3 is concurrent with a decrease in the level of phosph-tau and an increase in the clearance of tau in neuronal cells. Third, soon after destabilization of microtubules, tau associates with Hsp70/Hsc70, a key partner of BAG3. Fourth, induction of Tat in the brains of transgenic animals increases accumulation of phospho-tau. Thus, Tat- mediated reduction in the level of BAG3 may have a damaging effect on neuronal cells by interrupting the process that ensures intracellular removal of the toxic from of tau, yet maintains the healthy species of tau that is critical for neuronal cell function. Hyper-phosphorylation of tau, which contributes to its misfolding and toxicity, may be attributed to Tat via induction of ROS, ER stress, and mitochondrial dysfunctionality. The latter is of particular interest as truncated tau has been implicated in dysregulation of mitochondrial dynamics and healty energy metabolism. These observations prompted us to hypothesize that, on one hand, Tat impacts the quality and concentration of proper levels of functional tau and the clearance of its toxic form by suppressing expression of BAG3, and on the other hand, Tat contributes to the generation of the toxic tau and dysfunctionality of bioenergetic pathways and mitochondria by inducing stress conditions in cells. To examine this model, we will employ in vitro primary neuronal cultures, ex vivo animal brain tissue, and an in vivo animal model to unravel the underlying molecular basis of HIV-1/Tat-induced perturbation of PQC and homeostasis of tau in neuronal cell function.

项目摘要 据估计，在美国110万艾滋病毒阳性患者中，超过10％将超过65年 在不到十年的时间内，老年人是生活中的关键阶段 增加。临床研究的早期结果表明，多种异常，包括记忆难度， 思考，推理在老年艾滋病毒阳性患者中变得越来越普遍，这意味着他们的危险因素可能 与艾滋病毒负面对应物相比，要升高。这个概念提出了艾滋病毒的概念 即使在病毒受抗逆转录病毒疗法（ART）良好控制的患者中，感染也可能更容易 开发包括AD在内的神经退行性疾病。考虑艺术无法有效抑制 病毒蛋白的表达，包括HIV TAT，这是一种深刻的神经毒性蛋白，我们设想了一种情况 其中，通过失调蛋白质质量控​​制（PQC）途径，TAT可能会扰动钥匙的稳态 蛋白质与AD的发病机理相关，并为疾病的发展奠定了基础。几个数据 来自我们和其他实验室支持这个概念。首先，我们证明tat抑制了bag3的表达， HSP70的共伴侣/合作伙伴，参与去除功能失调和过时的细胞器 通过称为线粒体的过程包括线粒体，并参与自噬和清除 通过蛋白质质量控​​制（PQC）途径受损和折叠的蛋白质。第二，Bag3的激活是 同时发生的磷-TAU水平降低以及神经元细胞中TAU清除的增加。 第三，在微管破坏稳定后不久，tau与Bag3的主要合作伙伴HSP70/HSC70合作。 第四，转基因动物大脑中TAT的诱导增加了磷酸-TAU的积累。那，tat- BAG3水平介导的降低可能会通过中断神经元细胞具有破坏作用 确保细胞内去除毒物的过程，但保持健康的tau物种 对于神经元细胞功能至关重要。 Tau的高磷酸化，这有助于其错误折叠和毒性， 可以通过诱导ROS，ER应激和线粒体功能障碍来归因于TAT。后者是 在线粒体动力学和健康方面的失调中，特别感兴趣的tau已被忽略 能量代谢。这些观察结果促使我们假设一方面，TAT会影响质量 以及适当水平的功能性tau及其有毒形式的清除，通过抑制表达 Bag3的of，另一方面，Tat有助于产生有毒的tau和功能障碍 生物能途径和线粒体通过诱导细胞中的应力条件。要检查这个模型，我们将 采用体外原发性神经元培养物，离体动物脑组织和体内动物模型来揭示 HIV-1/TAT诱导的PQC和Tau稳态的扰动的基本分子基础在神经元细胞中 功能。