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Pathogenesis of Mouse Polyomavirus-associated CNS Demyelination

小鼠多瘤病毒相关中枢神经系统脱髓鞘的发病机制

基本信息

批准号：
9185385
负责人：
Aron Eliot Lukacher
金额：
$ 33.65万
依托单位：
PENNSYLVANIA STATE UNIV HERSHEY MED CTR
依托单位国家：
美国
项目类别：
财政年份：
2016
资助国家：
美国
起止时间：
2016-05-01 至 2021-03-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9185385
关键词：
Ablation Acquired Immunodeficiency Syndrome Acute Adrenal Cortex Hormones Affect Animal Model Antigens Antiviral Agents Astrocytes Autoimmune Diseases Autoimmune Process Axon Brain Brain Diseases Brain scan CD8B1 gene Cell Death Cell Maintenance Cells Central Nervous System Diseases Central Nervous System Infections Cerebral Edema Cessation of life Chronic Clinical Complement Complication Data Demyelinating Diseases Demyelinations Diagnosis Diffusion Magnetic Resonance Imaging Disease Dropout Equilibrium Evaluation Evolution Family Frequencies Fumarates Functional disorder Genes Goals Hematopoietic Highly Active Antiretroviral Therapy Histologic Human Immune Immunity Immunologic Deficiency Syndromes Immunologic Monitoring Immunotherapeutic agent In Situ In Vitro Individual Infection Infiltration Inflammation Inflammatory Infusion procedures Integrin alpha4 Integrin alpha4beta1 Interferon Type II Interruption Intervention JC Virus Life Link LoxP-flanked allele Lymphocytic Infiltrate Lytic Lytic Phase Magnetic Resonance Imaging Maintenance Mediating Modeling Mononuclear Multifocal Lesion Multiple Sclerosis Mus Myelin Neuroglia Nonlytic Oligodendroglia PDCD1LG1 gene Pathogenesis Pathway interactions Patients Phase Plasma Exchange Play Polyomavirus Polyomavirus Infections Population Production Progressive Multifocal Leukoencephalopathy Reaction Relapse Role Severities Signal Transduction Syndrome T cell differentiation T-Lymphocyte Testing Tissues Transgenic Mice Transgenic Organisms Tropism Viral Virus Virus Diseases Virus Replication cell type design drug withdrawal exhaustion humanized antibody in vivo insight mortality mouse model mouse polyomavirus multiple sclerosis patient mutant natalizumab neuroinflammation neuropathology novel pathogen prevent receptor recombinase reconstitution seropositive stem white matter

项目摘要

ABSTRACT Progressive Multifocal Leukoencephalopathy (PML) is a life-threatening demyelinating brain disease in immune-compromised individuals caused by the JC polyomavirus (JCV), a ubiquitous human-only pathogen. No anti-JCV agents are available. PML is a significant complication for patients receiving long-term natalizumab, a humanized antibody against α4 integrins that dramatically reduces relapses in multiple sclerosis (MS) patients. PML is being diagnosed with increasing frequency in patients treated with other immunomodulatory agents (e.g., Rituxamab, Efalixumab, Fingolimod, and dimethyl fumarate) as well. Drug withdrawal is often complicated by Immune Reconstitution Inflammatory Syndrome (IRIS), a severe inflammatory reaction with paradoxical worsening of demyelination that carries a high mortality rate. Lack of a tractable animal model for PML is a widely recognized hurdle to defining pathogenesis of demyelination in PML and PML-IRIS. Using mouse polyomavirus (MPyV), we developed a robust model of polyomavirus-associated demyelinating leukoencephalitis (brain white matter inflammation), with viral infection and T cell infiltration localized to subcortical white matter. For Specific Aim 1, we hypothesize that MPyV replicates predominantly in astrocytes early in infection, with neuroinflammation rather than viral infection causing oligodendrocyte loss; with α4 integrin blockade, however, oligodendrocyte dropout is delayed and results from MPyV replication extending to oligodendrocytes. To test this hypothesis, we developed a novel floxed MPyV mutant to conditionally restrict viral replication in Cre recombinase-expressing astrocytes or oligodendrocytes, and will use a mouse line with ablation of the α4 integrin gene in hematopoietic cells. Histologic and immunohistologic evaluation of MPyV-infected brains will be complemented by MRI diffusion tensor imaging to detect and quantify multifocal lesions and axon organizational integrity in whole brain scans. For Specific Aim 2 we hypothesize that IFN-γ, produced by MPyV-specific CD8 T cells, mediates a demyelinating leukoencephalitis in early infection, but confers protection in persistent infection. To test this hypothesis, we will use transgenic mice to conditionally ablate IFN-γ signaling in astrocytes and oligodendrocytes, and mice made chimeric with IFN-γ-sufficient/-deficient, MPyV-specific TCR transgenic CD8 T cells. For Specific Aim 3 we hypothesize that the PD-1:PD-L1 pathway balances MPyV-specific CD8 T cell-mediated control of CNS infection against their ability to promote neuroinflammation and demyelination. Anti-MPyV CD8 T cells infiltrating the brain are stably maintained and uniformly upregulate PD-1 inhibitory receptors. To test this hypothesis, we will study the in vivo function and fate of PD-1-/- T cells in brains of MPyV-infected mice, and apply chronic intracerebroventricular infusion of anti-PD-L1. This model of polyomavirus-associated CNS disease may provide insights for strategies to prevent or stem progression of this devastating demyelinating leukoencephalitis associated with immunomodulatory therapies for MS and other autoimmune/inflammatory diseases.

摘要进行性多灶性白质脑病（PML）是一种危及生命的脱髓鞘性脑病， JC多瘤病毒（JCV）是一种普遍存在的人类病原体，无抗JCV药物可用。PML是接受长期化疗的患者的重要并发症。那他珠单抗，一种针对α4整合素的人源化抗体，可显著降低多发性硬化症的复发率 (MS)患者在接受其他治疗的患者中，PML的诊断频率越来越高。免疫调节剂（例如，利妥昔单抗、依法昔单抗、芬戈莫德和富马酸二甲酯）。药物戒断通常并发免疫重建炎症综合征（IRIS），一种严重的炎性反应伴随着脱髓鞘的反常恶化，具有高死亡率。缺乏一个易于处理的PML动物模型是一个公认的障碍，以确定在PML脱髓鞘的发病机制 PML-IRIS。使用小鼠多瘤病毒（MPyV），我们开发了一个强大的多瘤病毒相关模型脱髓鞘性白质脑炎（脑白色物质炎症），伴病毒感染和T细胞浸润局限于皮质下白色物质。对于特异性目的1，我们假设MPyV主要复制在感染早期的星形胶质细胞中，神经炎症而不是病毒感染导致少突胶质细胞损失; 然而，在α4整合素阻断的情况下，少突胶质细胞的脱落被延迟，并由MPyV复制引起延伸到少突胶质细胞。为了验证这一假设，我们开发了一种新的floxed MPyV突变体，在表达Cre重组酶的星形胶质细胞或少突胶质细胞中有条件地限制病毒复制，使用造血细胞中α4整联蛋白基因缺失的小鼠系。组织学和免疫组织学将通过MRI扩散张量成像来补充对MPyV感染大脑的评估，在全脑扫描中量化多灶性病变和轴突组织完整性。对于特定目标2，我们假设由MPyV特异性CD 8 T细胞产生的IFN-γ介导了MPyV中的脱髓鞘性白质脑炎，早期感染，但在持续感染中提供保护。为了验证这一假设，我们将使用转基因小鼠，以条件性地消除星形胶质细胞和少突胶质细胞中的IFN-γ信号传导，以及与 IFN-γ-充足/-缺陷的MPyV特异性TCR转基因CD 8 T细胞。对于具体目标3，我们假设， PD-1：PD-L1途径平衡了MPyV特异性CD 8 T细胞介导的CNS感染控制与其促进神经炎症和脱髓鞘的能力。浸润脑的抗-MPyV CD 8 T细胞稳定表达。维持并均匀上调PD-1抑制性受体。为了验证这一假设，我们将研究体内 PD-1-/- T细胞在MPyV感染小鼠脑中的功能和命运，并将慢性脑室内输注抗PD-L1抗体。这种多瘤病毒相关CNS疾病的模型可能为制定策略提供见解以预防或阻止这种破坏性脱髓鞘性白质脑炎的进展， MS和其他自身免疫/炎性疾病的免疫调节疗法。