Role of Toll-like Receptors in Transplant-Induced Reactivation of Cytomegalovirus

Toll 样受体在移植诱导的巨细胞病毒再激活中的作用

• 批准号: 7906627
• 负责人: Michael M Abecassis
• 金额: $ 18.87万
• 依托单位: NORTHWESTERN UNIVERSITY AT CHICAGO
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-08-15 至 2011-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7906627
• 关键词: Allogenic; Allografting; Animal Model; Antibodies; Binding; Bone Marrow Suppression; Bone Marrow Transplantation; Cells; Chromatin; Cytomegalovirus; Data; Development; Early Promoters; Enhancers; Functional disorder; Gene Expression; Genes; Genetic Transcription; Goals; Herpesviridae; Homologous Transplantation; Immediate-Early Genes; Immune response; Immune system; Immunocompromised Host; Infection; Inflammatory; Injury; Ischemia; Kidney; Kidney Transplantation; Latent Virus; Lead; Ligands; Mediating; Mediator of activation protein; Modeling; Molecular; Morbidity - disease rate; Mus; Natural Immunity; Newborn Infant; Organ; Organ Donor; Pathway interactions; Patients; Pattern recognition receptor; Proteins; Receptor Signaling; Regulation; Relative (related person); Reperfusion Therapy; Resistance; Role; Signal Pathway; Signal Transduction; Signaling Molecule; Small Interfering RNA; Solid; T-Lymphocyte; TLR2 gene; TLR4 gene; TNF gene; Technology; Testing; Therapeutic; Toll-like receptors; Toxic effect; Transcription Factor AP-1; Transcriptional Regulation; Transplant Recipients; Transplantation; Viral; Viral Genes; Virus; adaptive immunity; base; chemokine; chromatin remodeling; combat; cytokine; gene induction; histone modification; in vivo; latent infection; mortality; novel strategies; pathogen; prevent; public health relevance; reactivation from latency; response; transcription factor

DESCRIPTION (provided by applicant): Reactivation of latent cytomegalovirus (CMV) is frequently observed in recipients of solid organs and bone marrow transplants and is also a significant cause of morbidity and mortality in newborns and in immunocompromised hosts. Currently available anti-viral therapies which target viral replication are associated with narrow therapeutic margins resulting in significant toxicities, including bone marrow suppression, especially in patients with renal dysfunction. Also, the increasing rates of resistance to these agents necessitates the use of efficacious but more toxic agents. It is generally accepted that immediate early (IE) genes are transcriptionally silent in latent infection, and that reactivation of IE gene expression is a critical first step in reactivation of the virus. Treatment with agents which prevent reactivation of IE gene expression would be a novel approach which would avoid problems associated with attempting to combat viral replication. The mechanisms by which reactivation of IE gene expression occurs 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 previously utilized a mouse kidney transplant model to induce transcriptional reactivation of MCMV in vivo. Our preliminary studies indicate that genes induced by Toll like receptors are up-regulated in allogeneic kidney transplants. We hypothesize that transcriptional reactivation of MCMV immediate early (IE) gene expression in response to transplantation is initiated by an innate immune response through interaction of Toll-like receptors with cellular ligands damaged by ischemic injury, and this is further amplified by recognition of MHC-incompatible cells. We hypothesize that this leads to increased expression of inflammatory cytokines such as TNF which can themselves activate the enhancer, and that signaling pathways activated by these factors leads to chromatin remodeling and reactivation of IE gene expression. Our preliminary data suggests a major role for TLR2 in activation of the cellular immune response to allogeneic transplants, and thus, for reactivation of MCMV. Through the use of TLR2 deficient mice and the use of siRNA technology to block expression in vivo, we propose to test the requirement for TLR2 as well as signaling adapters MyD88 and Trif in reactivation of MCMV IE gene expression in this model. Treatment of the donor organ prior to transplantation with agents such as siRNA that target steps required for initiation of reactivation would be a novel approach which would significantly reduce the problem of toxicity to the recipient. These studies may therefore lead to the development of new strategies to prevent reactivation of CMV and its sequelae. PUBLIC HEALTH RELEVANCE: Reactivation of latent cytomegalovirus can cause significant morbidity or mortality in immunocompromised transplant patients. Currently available anti-viral therapies, which target viral replication, are associated with severe toxicities and increasing rates of resistance. The goal of this proposal is to understand the molecular pathways that trigger reactivation of latent virus and to develop new strategies to prevent reactivation of latent virus.

描述（由申请人提供）：在固体器官和骨髓移植物的受体中经常观察到潜在的巨细胞病毒（CMV）的重新活化，这也是新生儿以及免疫强化宿主中发病率和死亡率的重要原因。目前，靶向病毒复制的可用抗病毒疗法与狭窄的治疗缘有关，导致毒性显着，包括骨髓抑制，尤其是在肾功能不全的患者中。同样，对这些药物的抵抗力的提高需要使用有效但有毒的药物。人们普遍认为，立即（IE）基因在潜在感染中是转录沉默的，而IE基因表达的重新激活是病毒重新激活的关键第一步。用防止IE基因表达重新激活的药物的治疗将是一种新型方法，该方法将避免与试图对抗病毒复制有关的问题。 IE基因表达的重新激活的机制尚不清楚。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作为研究CMV潜伏期和重新激活的模型。我们以前已经利用小鼠肾脏移植模型来诱导MCMV在体内的转录重新激活。我们的初步研究表明，同种异体肾移植中，TOLL LIKE受体诱导的基因被上调。我们假设MCMV立即对移植的转录重新激活（IE）基因表达是通过与缺血性损伤受损的细胞配体的相互作用的先天免疫反应引发的，并且通过识别MHC不合别细胞而进一步扩大了这一点。我们假设这会导致炎症细胞因子（例如TNF）的表达增加，例如TNF本身可以激活增强子，而这些因素激活的信号传导途径会导致IE基因表达的染色质重塑和重新激活。我们的初步数据表明，TLR2在激活同种异体移植的细胞免疫反应中起着主要作用，因此，MCMV的重新激活。通过使用TLR2缺乏小鼠并使用siRNA技术阻止体内表达，我们建议测试TLR2的需求以及信号适配器MyD88和TRIF在此模型中重新激活MCMV IE基因表达的需求。在用诸如siRNA诸如siRNA启动重新激活的目标步骤移植之前对供体器官的处理将是一种新型方法，这将大大减少对受体的毒性问题。因此，这些研究可能导致开发新策略，以防止CMV及其后遗症重新激活。公共卫生相关性：潜在的巨细胞病毒的重新激活可能会导致免疫功能低下的移植患者的显着发病率或死亡率。目前可用的抗病毒疗法（靶向病毒复制）与严重毒性和耐药发生率增加有关。该提案的目的是了解引发潜在病毒重新激活的分子途径，并制定新的策略以防止潜在病毒重新激活。