CNS Mechanisms of MCP-1 Transcription

MCP-1转录的中枢神经系统机制

• 批准号: 6841479
• 负责人: Sheila A. Barber
• 金额: $ 35.76万
• 依托单位: JOHNS HOPKINS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-07-15 至 2009-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6841479
• 关键词: AIDS dementia complex; AP1 protein; DNA footprinting; Macaca nemestrina; acetylation; astrocytes; chromatin immunoprecipitation; clinical research; enzyme activity; genetic polymorphism; genetic promoter element; genetic regulation; genetic transcription; helper T lymphocyte; histones; human subject; human tissue; immunogenetics; leukocyte count; longitudinal animal study; macrophage; messenger RNA; mitogen activated protein kinase; monocyte chemoattractant protein 1; neuroimmunomodulation; nuclear factor kappa beta; postmortem; simian immunodeficiency virus

DESCRIPTION (provided by applicant): Monocyte chemoattractant protein-1 (MCP-1), a pivotal chemokine mediating the infiltration and activation of monocyte/macrophages in the brain is consistently observed in HIV and SIV CNS disease. Recently, a dinucleotide polymorphism in the human MCP-1 promoter was linked to increased susceptibility to HAD, strengthening the role of MCP-1 in HIV neuropathogenesis. Intriguingly, these polymorphisms result in increased expression of MCP-1 but decreased binding of transcriptional activators. Since the mechanisms regulating MCP-1 expression in the CNS of HIV-infected individuals are not known, it is difficult to understand how these and potentially other genetic variations in the MCP-1 promoter influence MCP-1 expression in vivo. The goal of this application is to elucidate the mechanisms that regulate MCP-1 transcription in the CNS. These mechanisms are important for the design of immunomodulatory therapeutics to supplement antiviral drugs, particularly in the CNS where antiviral drugs are least effective. Using an accelerated consistent SIV macaque model, we have demonstrated that activation of ERK/MAPK correlates with transient expression of MCP-1 during acute infection. Sustained activation of p38/MAPK correlates with escalating ratios of CSF:plasma MCP-1 that correlate with severity of CNS lesions. Further, treatment of SIV-infected macaques with minocycline, a potent neuroprotective, anti-inflammatory drug significantly reduced activation of p38, reduced ratios of CSF:plasma MCP-1 and reduced severity of CNS lesions. These results suggest a mechanistic link between p38 activation and MCP-1 expression. Sustained activation of p38/MAPK results in nucleosomal remodeling, via phosphoacetylation of histone H3, that enhances the accessibility of cryptic, high-affinity binding sites for NF-kappa B in the MCP-1 promoter. We hypothesize that distinct sites in the MCP-1 promoter regulate early vs. late expression of MCP-1 during SIV infection of the CNS and that p38-mediated phosphoacetylation of histone H3 is integral to the mechanism regulating late MCP-1 transcription in vivo. Aim 1 will identify specific binding sites and transcription factors regulating MCP-1 transcription in macaque (longitudinally) and human brain (end stage disease) and determine if histone H3 phosphoacetylation is involved in chromatin remodeling of the MCP-1 promoter in vivo. Aim 2 will determine if decreased phosphoacetylation of histone H3 at the MCP-1 promoter correlates with the decreased activation of p38 and decreased expression of MCP-1 mRNA observed in SIV-infected macaques treated with minocycline. Aim 3 will determine if and how genetic variations in the macaque and human MCP-1 promoter impact binding of regulatory factors to the MCP-1 promoter in the CNS.

描述（由申请人提供）：在HIV和SIV CNS疾病中始终观察到单核细胞趋化蛋白-1（MCP-1），一种介导大脑中单核细胞/巨噬细胞浸润和激活的关键趋化因子。最近，人MCP-1启动子中的二核苷酸多态性与增加的易感性有关，从而增强了MCP-1在HIV神经病发生中的作用。有趣的是，这些多态性导致MCP-1表达增加，但转录激活剂的结合减少。由于未知HIV感染个体中CNS中MCP-1表达的机制尚不清楚，因此很难理解MCP-1启动子中这些和可能其他遗传变异如何影响体内MCP-1的表达。该应用的目的是阐明调节CNS中MCP-1转录的机制。这些机制对于设计免疫调节治疗剂来补充抗病毒药药很重要，尤其是在抗病毒药最有效的中枢神经系统中。使用加速一致的SIV猕猴模型，我们证明了ERK/MAPK的激活与急性感染过程中MCP-1的瞬时表达相关。 p38/MAPK的持续激活与CSF：等离子体MCP-1的升级比率与CNS病变严重程度相关的CSF：等离子MCP-1。此外，用米诺环素治疗SIV感染的猕猴，一种有效的神经保护性，抗炎药可显着降低p38的激活，CSF的比率降低：血浆MCP-1和CNS病变的严重程度降低。这些结果表明p38激活与MCP-1表达之间存在机理联系。 p38/MAPK的持续激活通过组蛋白H3的磷酸乙酰化导致核小体重塑，从而增强了MCP-1启动子中NF-KAPPA B的隐性，高亲和力结合位点的可及性。我们假设MCP-1启动子中的不同位点调节了CNS SIV感染期间MCP-1的早期表达，并且P38介导的组蛋白H3的磷酸乙酰化是调节VIVO中MCP-1转录晚期的机制的组成部分。 AIM 1将确定调节猕猴（纵向）和人脑中MCP-1转录的特定结合位点和转录因子（末期疾病），并确定组蛋白H3磷酸乙酰化是否参与体内MCP-1启动子的染色质重塑。 AIM 2将确定在MCP-1启动子处组蛋白H3的磷酸乙酰化是否与p38的激活降低以及在用米诺环素处理的SIV感染的猕猴中观察到的MCP-1 mRNA表达降低相关。 AIM 3将确定猕猴和人MCP-1启动子的遗传变异是否影响调节因子与CNS中MCP-1启动子的结合。