The HIV-Osteopontin-HAND Triad: Inflammation and Neuronal Injury in the Brain

HIV-骨桥蛋白-HAND 三联征：大脑炎症和神经元损伤

• 批准号: 9271454
• 负责人: AMANDA MARIA BROWN
• 金额: $ 39.81万
• 依托单位: JOHNS HOPKINS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-09-30 至 2021-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9271454
• 关键词: 1-Phosphatidylinositol 3-Kinase; Aftercare; Anti-Retroviral Agents; Antibodies; Antiviral Agents; Astrocytes; Autopsy; Behavior; Blocking Antibodies; Brain; CD44 gene; Cells; Chronic; Cognitive; DNA; Data; Event; Feedback; Functional disorder; Future; Gene Expression; Genetic Transcription; Goals; HIV; HIV Envelope Protein gp120; HIV Infections; HIV tat Protein; HIV-associated neurocognitive disorder; Harvest; Human; Immune; Immunochemistry; Impairment; In Vitro; Incidence; Individual; Infection; Inflammation; Inflammatory; Inflammatory Response; Injury; Integrins; Knowledge; Life; Measures; Mediating; Memory; Messenger RNA; Microglia; Mitogen-Activated Protein Kinase Kinases; Mitogens; Modeling; Molecular; Motor; Mus; Nerve Degeneration; Neuraxis; Neurocognition; Neurodegenerative Disorders; Neuroglia; Neuronal Dysfunction; Neuronal Injury; Neurons; Pathway interactions; Positron-Emission Tomography; Prevalence; Process; Production; Proteins; RNA; Recombinants; Rodent; Signal Transduction; Site; Systemic infection; Testing; Time; Tissues; Triad Acrylic Resin; Viral Genes; Viral Load result; Virus Replication; aptamer; axon injury; behavior test; brain tissue; central nervous system injury; cognitive function; cost effective; cytokine; executive function; in vivo; inflammatory marker; inhibitor/antagonist; knock-down; macrophage; monocyte; neurocognitive test; neuroinflammation; neurotoxic; novel therapeutic intervention; osteopontin; radiotracer; receptor; response; translational study

Even in HIV-infected individuals on active anti-retroviral therapy (ART), low-level viral replication and inflammation persists in both the periphery and in the central nervous system (CNS). HIV enters the brain early and there is compelling evidence that the brain is a putative reservoir for HIV that is responsible for the neuropathogenic sequelae. Indeed, even with ART, the prevalence and incidence of HAND remains high. While progress has been made in understanding the pathophysiology of HAND under conditions of high viral load, the hosts’ inflammatory responses to low-level chronic systemic infection and how this exacerbates neuronal injury and dysfunction in the brain are incompletely understood. Osteopontin (OPN), an early marker of inflammation is elevated in HAND. OPN may be a key intercellular signaling linker between neurons, macrophages/microglia and astrocytes in the CNS. We, and other groups, found that OPN is increased in HAND, even in those on therapy. OPN is significantly expressed in astrocytes, microglia and neurons in HAND. Thus, OPN increases in response to HIV infection. These findings suggest that OPN is a putative contributor to neuropathogenic processes in HAND. A feedback loop exists between OPN and HIV. Indeed, we showed a strong relationship between viral gene expression and the induction of OPN. Knockdown of OPN in macrophages led to a 50% reduction in HIV production, suggesting that this cytokine stimulates viral replication. Indeed inhibition of OPN blocks HIV transcription and replication in macrophages. Our findings show that OPN enhances HIV replication through NF-B and via activation of OPN receptors, integrins and CD44. In macrophages, OPN is required for the downstream activation of mitogen-activated kinases (MAPKs), innate and inflammatory pathways, implicated in HAND. Together, our data suggests that OPN is an important regulator of both HIV replication and proinflammatory signaling in cells of the CNS. Hence, it is critical that we understand OPN signaling and downstream inflammatory cascades in order to develop new therapeutic interventions. Our central hypothesis is that in the context of systemic HIV infection, OPN expression in activated macrophages/microglia, astrocytes and neurons promotes integrin and CD44 signaling cascades resulting in chronic inflammation and subsequent injury of neurons. A three-pronged approach will be used to explore our hypothesis: 1) in vivo, using HIV-infected NOD-scid IL-2R mouse engrafted with human hCD34+. In this model, several key neuropathological hallmarks seen in HAND are observed, it allows persistent HIV replication, and mice can be treated with antivirals, 2) in vitro, using primary macrophage, neuronal, and astrocytic cultures to deconstruct the molecular mechanisms, and 3) ex vivo, using human brain postmortem tissue to validate experimental findings. We expect that the new knowledge gained will allow for future translational studies aimed at alleviating neuronal and cognitive damage in HAND. This is especially important as to date, no viable adjunctive therapy has yet been identified.

即使在接受积极抗逆转录病毒治疗（ART）的艾滋病毒感染者中， 炎症持续存在于外周和中枢神经系统（CNS）中。艾滋病毒早期进入大脑 有令人信服的证据表明，大脑是艾滋病毒的假定储存库， 神经病后遗症事实上，即使有ART，HAND的患病率和发病率仍然很高。 虽然在理解HAND在高病毒感染条件下的病理生理学方面取得了进展， 负荷，宿主对低水平慢性全身性感染的炎症反应以及这种反应如何加剧 脑中的神经元损伤和功能障碍尚未完全了解。骨桥蛋白（OPN），一种早期标志物 炎症的程度在手部升高。OPN可能是神经元之间的关键细胞间信号连接体， 巨噬细胞/小胶质细胞和星形胶质细胞。我们和其他研究小组发现， 手，即使在那些治疗。OPN在星形胶质细胞、小胶质细胞和神经元中显著表达， 手因此，OPN在对HIV感染的反应中增加。这些发现表明OPN是一种假定的 HAND中的神经致病过程的贡献者。OPN和HIV之间存在反馈回路。我确 显示病毒基因表达与OPN诱导之间存在强相关性。OPN的敲除 巨噬细胞导致HIV产生减少50%，这表明这种细胞因子刺激病毒 复制的事实上，OPN的抑制阻断了HIV在巨噬细胞中的转录和复制。我们的研究结果 显示OPN通过NF-κ B B和通过激活OPN受体、整合素和 CD44。在巨噬细胞中，OPN是促分裂原活化激酶（MAPK）下游活化所必需的， 先天性和炎症途径，涉及手。总之，我们的数据表明，OPN是一种 是CNS细胞中HIV复制和促炎信号传导的重要调节剂。因此 我们了解OPN信号传导和下游炎症级联反应， 开发新的治疗干预措施。我们的中心假设是，在系统性艾滋病毒感染的情况下， 感染后，活化的巨噬细胞/小胶质细胞、星形胶质细胞和神经元中的OPN表达促进整合素和 CD 44信号级联导致慢性炎症和随后的神经元损伤。三管齐下 我们将采用以下方法来探讨我们的假设：1）在体内，使用HIV感染的NOD-scid IL-2 R， 移植人hCD 34+的小鼠。在该模型中，在HAND中观察到的几个关键神经病理学标志 观察到，它允许持续的HIV复制，并且小鼠可以用抗病毒药物治疗，2）在体外，使用 原代巨噬细胞、神经元和星形胶质细胞培养物，以解构分子机制，以及3） 体内，使用人脑死后组织来验证实验结果。我们希望新的 所获得的知识将允许未来旨在减轻神经元和认知损伤的转化研究 手里这一点尤其重要，因为到目前为止，还没有确定可行的治疗方法。