Epigenetic control of cytomegalovirus latency and reactivation

巨细胞病毒潜伏期和再激活的表观遗传控制

• 批准号: 7472839
• 负责人: MARY A HUMMEL
• 金额: $ 22.65万
• 依托单位: NORTHWESTERN UNIVERSITY AT CHICAGO
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-04-01 至 2010-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7472839
• 关键词: Acute; Animal Model; Binding; Biological Assay; Bone Marrow Transplantation; Cause of Death; Cells; Characteristics; Chromatin; Complex; Cytomegalovirus; Development; Disease; EP300 gene; Early Promoters; Enhancers; Epigenetic Process; Fetus; Future; Gene Expression; Genes; Goals; Herpesviridae; Histones; Homologous Transplantation; Immune response; Immune system; Immunocompromised Host; Infection; Inflammatory; Kidney; Kidney Transplantation; Latent Virus; Lead; Modeling; Modification; Molecular; Morbidity - disease rate; Mus; NF-kappa B; Neurologic; Newborn Infant; Organ; Pathway interactions; Pregnancy; Proteins; Public Health; Recruitment Activity; Signal Pathway; Simplexvirus; Site; Solid; Staging; Stimulus; TNF gene; Testing; Transcription Coactivator; Transcription Repressor/Corepressor; Transplantation; Virus; base; chromatin immunoprecipitation; chromatin remodeling; in vivo; latent infection; mortality; prevent; reactivation from latency; transcription factor; viral DNA

DESCRIPTION (provided by applicant): HCMV is a ubiquitous herpesvirus which has the ability to establish a lifelong latent infection. Reactivation of latent virus is frequently observed in recipients of solid organs and bone marrow transplants and is a significant cause of morbidity and mortality in newborns and in immunocompromised hosts. Latency is operationally defined as the inability to detect infectious virus despite the presence of viral DNA. However, the molecular mechanisms by which CMV establishes a latent infection and reactivates from latency are not well understood. Because of the lack of animal models to study HCMV infection in vivo, we and others have used MCMV as a model to study CMV latency and reactivation. We have developed a transplant model for transcriptional reactivation of IE gene expression. On the basis of these studies, we have hypothesized that CMV establishes a true latent infection in which genes associated with productive infection, including the IE genes, are not expressed, and that transcriptional reactivation is due to activation of signaling pathways which lead to binding of transcription factors to their cognate sites in the enhancer. Here we hypothesize that transcriptional silencing in latent infection is due to interaction of the major immediate early promoter (MIEP) with proteins which maintain the chromatin in a condensed and transcriptionally inactive state. The virus would be able to persist in this state because latently infected cells would be invisible to the host immune response. We further hypothesize that transcriptional reactivation is induced by inflammatory stimuli which result in changes in the histones associated with the MIEP such that they acquire modifications associated with transcriptionally active chromatin. These modifications lead to opening of the chromatin which allows transcription factors such as NFkB access to the MIEP. We hypothesize that transcriptional reactivation of IE gene expression is accompanied both by chromatin remodeling and by binding of NFkB to the MIEP. We propose to test this hypothesis by using chromatin immunoprecipitation assays to characterize coactivators, transcription factors, transcriptional repressors and modification of histones associated with the MIEP during acute and latent infection and after reactivation induced by transplantation. These studies will form the basis for a future R01 investigating mechanisms by which chromatin remodeling proteins are recruited to the MIEP. These studies will advance our understanding of the mechanisms of CMV latency and reactivation and may lead to development of new therapies to prevent CMV disease. PUBLIC HEALTH RELEVANCE: Cytomegalovirus (CMV) is a ubiquitous herpesvirus which establishes a lifelong latent infection in which the viral DNA is present, but no virus is produced. Primary infection with CMV during pregnancy can cause death or serious neurological complications in the fetus. Reactivation of latent virus can cause significant morbidity or mortality in immunocompromised patients. The goal of this proposal is to understand the molecular mechanisms by which the virus establishes latent infection and the molecular pathways that trigger reactivation of latent virus. These studies will advance our understanding of the mechanisms of CMV latency and reactivation and may lead to development of new therapies to prevent CMV disease.

描述（由申请方提供）：HCMV是一种普遍存在的疱疹病毒，具有建立终身潜伏感染的能力。在实体器官和骨髓移植的接受者中经常观察到潜伏病毒的再活化，并且是新生儿和免疫受损宿主中发病和死亡的重要原因。潜伏期在操作上被定义为尽管存在病毒DNA但不能检测到感染性病毒。然而，CMV建立潜伏感染并从潜伏期重新激活的分子机制还不清楚。由于缺乏研究体内HCMV感染的动物模型，我们和其他人使用MCMV作为模型来研究CMV潜伏期和再激活。我们已经建立了一个移植模型，转录激活IE基因表达。在这些研究的基础上，我们假设CMV建立了一个真正的潜伏感染，其中与生产性感染相关的基因，包括IE基因，不表达，转录再激活是由于激活的信号传导途径，导致转录因子结合到其同源位点的增强子。在这里，我们假设，在潜伏感染的转录沉默是由于主要立即早期启动子（MIEP）与蛋白质的相互作用，保持染色质在一个浓缩和转录失活状态。病毒能够在这种状态下持续存在，因为潜伏感染的细胞对宿主免疫反应是不可见的。我们进一步假设转录再激活是由炎症刺激诱导的，炎症刺激导致与MIEP相关的组蛋白发生变化，从而获得与转录活性染色质相关的修饰。这些修饰导致染色质开放，从而允许NFkB等转录因子进入MIEP。我们推测，转录激活IE基因表达是伴随着染色质重塑和NFkB的结合MIEP。我们建议使用染色质免疫沉淀试验来测试这一假设，以表征辅激活因子，转录因子，转录抑制因子和修改组蛋白与MIEP在急性和潜伏感染和移植诱导的再激活后。这些研究将成为未来R01研究染色质重塑蛋白被募集到MIEP的机制的基础。这些研究将促进我们对CMV潜伏期和再激活机制的理解，并可能导致开发新的治疗方法来预防CMV疾病。 公共卫生关系：巨细胞病毒（CMV）是一种普遍存在的疱疹病毒，其建立终身潜伏感染，其中存在病毒DNA，但不产生病毒。妊娠期间CMV的原发性感染可导致胎儿死亡或严重的神经系统并发症。潜伏病毒的再活化可导致免疫功能低下患者的显著发病率或死亡率。该提案的目标是了解病毒建立潜伏感染的分子机制和触发潜伏病毒再激活的分子途径。这些研究将促进我们对CMV潜伏期和再激活机制的理解，并可能导致开发新的治疗方法来预防CMV疾病。