GPR75: a new CCL5 receptor that mediates neuroprotection against HIV

GPR75：一种新的 CCL5 受体，介导针对 HIV 的神经保护

基本信息

批准号：
8845810
负责人：
Italo Mocchetti
金额：
$ 19.44万
依托单位：
GEORGETOWN UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2014
资助国家：
美国
起止时间：
2014-09-30 至 2016-08-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8845810
关键词：
1-Phosphatidylinositol 3-Kinase Affect Affinity Agonist Alzheimer&apos s Disease Amino Acids Amyloid Apoptotic Astrocytes Binding Brain CC chemokine receptor 1 CCL3 gene CCL4 gene CCL7 gene CCR1 gene CCR5 gene CXCR4 gene Cells Chemokine (C-C Motif) Receptor 5 Coupled Data Development Drug Design Excitatory Amino Acids Family Fostering G alpha q Protein G-Protein-Coupled Receptors Glutamates HIV HIV Envelope Protein gp120 HIV-1 Human Immune Immune response Immune system In Vitro Infection Inositol Lead Leukocytes Ligands Link Mass Spectrum Analysis Mediating Microglia Mitogen-Activated Protein Kinases Molecular Models Nerve Degeneration Neuraxis Neurons Neuropeptides Organ Orphan Pathway interactions Pharmaceutical Preparations Play Property Protein Engineering Proteins Proto-Oncogene Proteins c-akt RANTES Research Rodent Role Signal Transduction Signal Transduction Pathway Signaling Molecule Spleen Surface Plasmon Resonance Synapses T-Lymphocyte Testing Thymus Gland Time Viral Proteins Virus Diseases beta-Chemokines chemokine chemokine receptor computational chemistry crosslink design env Gene Products innovation interest knock-down macrophage model design molecular modeling neuron loss neuronal survival neuroprotection neurotoxic neurotoxicity novel prevent public health relevance receptor receptor internalization research study small hairpin RNA small molecule tripolyphosphate virus envelope

项目摘要

DESCRIPTION (provided by applicant): One challenge in Human Immunodeficiency Virus (HIV) research involves the discovery and characterization of compounds that prevent or limit the neurodegeneration that follows HIV infection of the brain. The chemokine CCL5 inhibits entry of M-tropic HIV strains into macrophages/microglia by affecting the binding of the envelop protein gp120 to the co-receptor CCR5. Interestingly, CCL5 also prevents neuronal cell death mediated by the T-tropic gp120 and the viral protein Tat, which have no affinity for CCR5. Therefore, the mechanism of action of this chemokine remains to be fully characterized. Recent studies and our preliminary data have shown that CCL5 activates a G protein coupled-receptor 75 (GPR75) which encodes for a 540 amino-acid orphan receptor of the Gq¿ family. This receptor is more abundant in the brain than in the immune organs. Moreover, CCL5 activates various pro-survival signaling molecules, including inositol triphosphate, phosphatidylinositol 3-kinase and its downstream targets protein kinase B and extracellular signal-regulated kinases, in SH-SY5Y cells. These cells do not express CCR5, CCR3 and CCR1, receptors known to bind to CCL5. Moreover, CCL4, CCL7 and CCL3, other chemokines that bind to CCR5, CCR3 and CCR1, failed to activate these signaling molecules in these cells. Therefore, GPR75 could be the missing link to explain the neuroprotective activity of CCL5. In this exploratory proposal we will test the innovative hypothesis that GPR75 activation by CCL5 promotes neuroprotection against viral proteins (e.g. gp120 and Tat). To test this hypothesis, we propose to identify and characterize CCL5 binding activity and affinity for GPR75 by Scatchard analysis, cross-linking, receptor internalization, mass spectrometry and surface plasmon resonance (Biacore) studies (AIM 1) in both human as well as rodent neurons. These experiments will be accompanied by studies examining the role of GPR75 in CCL5-mediated neuroprotection against T-tropic gp120 and Tat in neurons in vitro (AIM 2). We expect to provide new significant data on the ability of CCL5 to bind to GPR75 and its role in preventing the neurotoxicity of HIV proteins. These data will help in the design of small molecule GPR75 agonists as an adjunct therapy against synaptic simplification caused by HIV.

描述（由申请人提供）：人类免疫缺陷病毒（HIV）研究中的一项挑战涉及预防或限制 HIV 感染大脑后神经变性的化合物的发现和表征。趋化因子 CCL5 抑制 M 向性 HIV 病毒株进入大脑。通过影响巨噬细胞/小胶质细胞的包膜蛋白 gp120 与辅助受体 CCR5 的结合，CCL5 还可以防止由 CCR5 介导的神经元细胞死亡。 T-tropic gp120 和病毒蛋白 Tat 对 CCR5 没有亲和力，因此，该趋化因子的作用机制仍有待充分表征。最近的研究和我们的初步数据表明，CCL5 激活 G 蛋白偶联受体 75。 (GPR75)，编码 Gq¿ 的 540 个氨基酸孤儿受体该受体在大脑中比在免疫器官中更丰富，此外，CCL5 还能激活各种促生存信号分子，包括肌醇三磷酸、磷脂酰肌醇 3-激酶及其下游靶标蛋白激酶 B 和细胞外信号调节激酶。 SH-SY5Y 细胞不表达已知与 CCL5 结合的 CCR5、CCR3 和 CCR1 受体。 CCL3 以及与 CCR5、CCR3 和 CCR1 结合的其他趋化因子未能激活这些细胞中的这些信号分子，因此，GPR75 可能是解释 CCL5 神经保护活性的缺失环节。 CCL5 激活 GPR75 促进针对病毒蛋白（例如 gp120 和 Tat）的神经保护。为了检验这一假设，我们建议鉴定和表征 CCL5 结合活性。通过 Scatchard 分析、交联、受体内化、质谱和表面等离振子共振 (Biacore) 研究 (AIM 1) 在人类和啮齿动物神经元中对 GPR75 进行亲和力研究。这些实验将同时进行检查 GPR75 作用的研究。在体外 CCL5 介导的针对 T 向性 gp120 和 Tat 的神经保护中（AIM 2），我们期望提供有关 CCL5 结合能力的新的重要数据。 GPR75 及其在预防 HIV 蛋白神经毒性中的作用这些数据将有助于设计小分子 GPR75 激动剂作为针对 HIV 引起的突触简化的辅助疗法。