Mechanisms of HIV Tat neurotoxicity and CCL2 protection

HIV Tat神经毒性和CCL2保护机制

• 批准号: 7031511
• 负责人: Joan Weinberger Berman
• 金额: $ 5.6万
• 依托单位: ALBERT EINSTEIN COLLEGE OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-02-17 至 2009-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7031511
• 关键词: AIDS /HIV neuropathy; HIV infections; apoptosis; biological signal transduction; chemokine; clinical research; endocytosis; excitatory aminoacid; human fetus tissue; human immunodeficiency virus; inflammation; intermolecular interaction; intracellular; neurons; neuropathology; neuroprotectants; neurotoxicology; neurotoxins; nitric oxide synthase; protein protein interaction; tissue /cell culture; transcription factor; virus cytopathogenic effect; virus protein

DESCRIPTION (provided by applicant): HIV infection of the CNS can result in neurologic dysfunction that has devastating consequences in a significant number of individuals with AIDS, including motor impairment and cognitive deficits. NeuroAIDS is characterized by neuronal injury and loss, yet there is no evidence of HIV positive neurons. Therefore, the altered function and apoptosis seen in neurons must be due to indirect effects of HIV infection of other CNS cells, including the elaboration of neurotoxic viral proteins, such as tat. Others and we demonstrated that HIV tat is toxic to human neurons. The first goal of this proposal is to identify the signaling pathways that mediate tat-induced apoptosis. Our data suggest that the mechanisms that mediate tat induced apoptosis can be divided into early and late stages. Our hypothesis is that the early events leading to apoptosis involve LRP-mediated tat endocytosis and immediate activation of NMDA channels. These activities are not sufficient to induce cell death. These early events subsequently result in later activation of signaling pathways and additional NMDA channels, leading to the dysregulation of glutamate and NO production, resulting in neuronal apoptosis. Chemokines play an important role in CNS inflammation. While their function in chemotaxis is essential, we identified a novel role for one chemokine, CCL2 (MCP-1), demonstrating that it protects human mixed cultures of neurons and astrocytes from tat-induced apoptosis. Our second goal is to determine the mechanisms by which CCL2 mediates its protection. Our data indicate that CCL2 reduces tat internalization into neurons. While cotreatment of cultures with tat and CCL2 inhibits apoptosis, addition of CCL2 2h after tat treatment does not abrogate tat induced cell death. We propose that CCL2 acts on the early phase of tat-induced apoptosis by altering endocytosis of tat and the intracellular signaling pathways activated during tat internalization. We will: 1. Determine the mechanisms that mediate tat internalization into neurons and the immediate early consequences of this uptake, including changes in protein-protein interactions involved in tat internalization (LRP, PSD-95), and the activation of signaling molecules (PSD-95, Fyn, Pyk2) and effector proteins (NMDA channels, nNOS) that may be involved in regulation of tat induced neuronal apoptosis. 2.Determine the mechanisms by which CCL2 alters tat endocytosis and the signaling pathways responsible for tat-induced apoptosis. 3. Analyze the late pathways involved in tat-induced apoptosis, including expression and activity of NMDA channels, dysregulation of extracellular glutamate and production of NO.

描述（由申请人提供）：中枢神经系统的HIV感染会导致神经功能障碍，在包括运动障碍和认知缺陷在内的大量艾滋病患者中具有毁灭性后果。神经辅助的特征是神经元损伤和丧失，但没有艾滋病毒阳性神经元的证据。因此，在神经元中看到的功能和凋亡的改变必须是由于其他中枢神经系统细胞的HIV感染的间接作用，包括阐述神经毒性病毒蛋白，例如TAT。其他人，我们证明了艾滋病毒对人类神经元有毒。该提案的第一个目标是确定介导TAT诱导凋亡的信号传导途径。我们的数据表明，介导TAT诱导凋亡的机制可以分为早期和晚期。我们的假设是导致凋亡的早期事件涉及LRP介导的TAT内吞作用和NMDA通道的立即激活。这些活动不足以诱导细胞死亡。这些早期事件随后导致了以后的信号通路和其他NMDA通道的激活，导致谷氨酸的失调和无生产，导致神经元细胞凋亡。趋化因子在CNS炎症中起重要作用。尽管它们在趋化性中的功能至关重要，但我们确定了一种趋化因子CCL2（MCP-1）的新作用，表明它保护了神经元和星形胶质细胞的人类混合培养物免受TAT诱导的细胞凋亡的影响。我们的第二个目标是确定CCL2介导其保护的机制。我们的数据表明，CCL2将TAT内在化降低到神经元中。尽管TAT和CCL2的培养物的共进行抑制了凋亡，但在TAT处理后添加CCL2 2H并不能消除TAT诱导的细胞死亡。我们提出，CCL2通过改变TAT的内吞作用和在TAT内部化过程中激活的细胞内信号传导途径来作用于TAT诱导的凋亡的早期。 We will: 1. Determine the mechanisms that mediate tat internalization into neurons and the immediate early consequences of this uptake, including changes in protein-protein interactions involved in tat internalization (LRP, PSD-95), and the activation of signaling molecules (PSD-95, Fyn, Pyk2) and effector proteins (NMDA channels, nNOS) that may be involved in regulation of tat诱导神经元凋亡。 2.确定CCL2改变TAT内吞作用和负责TAT诱导凋亡的信号传导途径的机制。 3。分析参与TAT诱导的凋亡中涉及的后期途径，包括NMDA通道的表达和活性，细胞外谷氨酸的失调以及NO的产生。