A TLR3-STAT3-miR-155 axis and astrocyte-myeloid crosstalk in viral encephalitis

病毒性脑炎中的 TLR3-STAT3-miR-155 轴和星形胶质细胞-骨髓串扰

基本信息

批准号：
10066377
负责人：
SONIA NAVAS-MARTIN
金额：
$ 34.01万
依托单位：
DREXEL UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2018
资助国家：
美国
起止时间：
2018-01-01 至 2022-12-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10066377
关键词：
Ablation Acute Adaptor Signaling Protein Affect Agonist Antiviral Response Astrocytes Autoimmunity Automobile Driving Binding Sites Blood - brain barrier anatomy Brain CCL2 gene Cells Central Nervous System Infections Chemotactic Factors Clinical Coronavirus Coronavirus Infections Double Stranded RNA Virus Double-Stranded RNA Encephalitis Exhibits Functional disorder Genetic Glial Fibrillary Acidic Protein Growth Factor Homeostasis ITGAM gene Immune Immune response Immunotherapy In Vitro Infection Infiltration Inflammation Inflammatory Interferon-beta Interferons Interleukin-1 Receptors Lead Leukocytes MHV-JHM Maintenance Matrix Metalloproteinases Mediating MicroRNAs Modeling Molecular Morbidity - disease rate Murine hepatitis virus Mus Myelogenous Myeloid Cells Necrosis Neuraxis Neuroglia Neuropathogenesis Neutrophil Infiltration Pathogenesis Pattern recognition receptor Pharmacology Play Poly I-C Poly(A)+ RNA Protein Tyrosine Kinase Proteins RNA Virus Infections RNA Viruses Regulation Resistance Role STAT protein STAT3 gene Signal Pathway Signal Transduction Source Suppressor of Cytokine Signaling Family Protein TLR3 gene Up-Regulation Viral Encephalitis Viral Load result Virus Diseases Wild Type Mouse base blood-brain barrier disruption brain endothelial cell cell type cerebral microvasculature chemokine cytokine exosome improved in vivo macrophage monocyte mortality neuroinflammation neurotropic neurotropic virus novel novel therapeutic intervention overexpression pathogen promoter receptor recruit response sensor transcription factor

项目摘要

ABSTRACT The maintenance of homeostasis in the central nervous system (CNS) during neurotropic viral infections is critical for host survival. Inflammation of the CNS is characterized by the recruitment of leukocytes to the brain and the activation of resident CNS cells, including astrocytes. The pivotal in vivo function of astrocytes during viral encephalitis is poorly defined. Toll like receptor 3 (TLR3) is an interferon-inducing double stranded RNA sensor that senses viral infections. Although it is well known that astrocytes express functional TLR3, its role in response to viral RNA infections of the CNS remains poorly understood. The interplay between transcription factors and microRNAs, and their upstream pattern recognition receptors during viral encephalitis has not been extensively studied. MicroRNA-155 (miR-155) has a key role of in the fine-tuning of TLR responses, and exerts both positive and negative regulation during inflammation. We and others have identified miR-155 as one of the most over- expressed miRNAs after stimulation of TLR3 with the synthetic dsRNA agonist Poly (I:C) in macrophages. In the CNS, miR-155 is also expressed in glial cells. However, a CNS-intrinsic role of miR-155 has yet to be defined in vivo. Signal transducers and activators of transcription (STAT) proteins and their negative regulators, the suppressors of cytokine signaling (SOCS) protein family play central roles in regulating many cytokines and growth factors. Recently, two STAT3 binding sites have been identified in the promoter of miR-155. Furthermore, miR-155 targets SOCS1 and SOCS3 suppressing their negative regulatory effect on JAK/STAT signaling pathway. Coronaviruses (CoVs) are enveloped, positive-sense, single-stranded, polyadenylated RNA viruses. Mouse hepatitis virus JHM (MHV-JHM) is a CNS-tropic strain that induces fatal encephalitis, associated with non-protective, enhanced macrophage and neutrophil infiltration that correlates with exacerbated chemokine and Th1 response and no Th17 involvement. We have identified a TLR3-dependent, miR-155 /STAT3 regulatory loop that promotes exacerbated, detrimental neuroinflammation and blood brain barrier (BBB) disruption in response to MHV-JHM fatal infection. Intriguingly, TRIF, the only TLR3 adaptor known, is not required for TLR3- dependent activation of STAT3 and induction of miR-155 both in vitro and in vivo. We have identified astrocytes and inflammatory monocytes infiltrating the brain as the cell sources driving exacerbated STAT3 activation. Our findings prompted us to investigate the following hypotheses: AIM 1 MHV-JHM infection in astrocytes and macrophages induces STAT3 activation through a TRIF-independent, TLR3-dependent non-canonical axis that is negatively regulated by its adaptor TRIF; AIM 2 Cell type specific genetic ablation of STAT3 and miR-155 expression in astrocytes or myeloid cells will reduce detrimental neuroinflammation and increase host survival after fatal MHV-JHM infection; and AIM 3 TLR3 contributes to BBB disruption through early and sustained upregulation of miR-155 expression in astrocytes, which deliver exosome-miR155 to brain endothelial cells affecting the expression of (to be identified in AIM 3) AJPs, TJPs, and/or MMPs.

抽象的在嗜神经病毒感染期间维持中枢神经系统（CNS）的稳态至关重要为了宿主的生存。中枢神经系统炎症的特点是白细胞募集到大脑和激活常驻中枢神经系统细胞，包括星形胶质细胞。星形胶质细胞在病毒感染过程中的关键体内功能脑炎的定义不明确。 Toll 样受体 3 (TLR3) 是一种干扰素诱导双链 RNA 传感器感知病毒感染。尽管众所周知星形胶质细胞表达功能性 TLR3，但其在反应中的作用中枢神经系统病毒 RNA 感染的机制仍知之甚少。转录因子与转录因子之间的相互作用病毒性脑炎期间的 microRNA 及其上游模式识别受体尚未得到广泛研究研究过。 MicroRNA-155 (miR-155) 在 TLR 反应的微调中发挥关键作用，并发挥积极作用以及炎症期间的负调节。我们和其他人已经确定 miR-155 是最过度研究的之一。用合成的 dsRNA 激动剂 Poly (I:C) 刺激巨噬细胞中的 TLR3 后表达 miRNA。在 CNS中，miR-155也在神经胶质细胞中表达。然而，miR-155 的中枢神经系统内在作用尚未确定。体内。信号转导子和转录激活子 (STAT) 蛋白及其负调节子细胞因子信号传导抑制蛋白 (SOCS) 蛋白家族在调节许多细胞因子和生长因子。最近，在 miR-155 的启动子中发现了两个 STAT3 结合位点。此外， miR-155 靶向 SOCS1 和 SOCS3，抑制它们对 JAK/STAT 信号传导的负调节作用途径。冠状病毒 (CoV) 是有包膜、正义、单链、聚腺苷酸化 RNA 病毒。小鼠肝炎病毒 JHM (MHV-JHM) 是一种嗜中枢神经系统菌株，可诱发致命性脑炎，与非保护性巨噬细胞和中性粒细胞浸润增强，与趋化因子加剧相关和 Th1 反应，没有 Th17 参与。我们已经确定了 TLR3 依赖的 miR-155 /STAT3 调节循环会促进恶化、有害的神经炎症和血脑屏障 (BBB) 破坏对 MHV-JHM 致命感染的反应。有趣的是，TRIF，唯一已知的 TLR3 适配器，对于 TLR3 来说并不是必需的。体外和体内 STAT3 的依赖性激活和 miR-155 的诱导。我们已经鉴定出星形胶质细胞浸润大脑的炎症单核细胞是驱动 STAT3 加剧激活的细胞来源。我们的研究结果促使我们研究以下假设：星形胶质细胞中的 AIM 1 MHV-JHM 感染和巨噬细胞通过 TRIF 独立、TLR3 依赖的非规范轴诱导 STAT3 激活，受到其接头 TRIF 的负向调节； AIM 2 STAT3 和 miR-155 的细胞类型特异性基因消除在星形胶质细胞或骨髓细胞中表达将减少有害的神经炎症并增加宿主的存活率致命的 MHV-JHM 感染后； AIM 3 TLR3 通过早期和持续的方式导致 BBB 破坏星形胶质细胞中 miR-155 表达上调，将外泌体-miR155 传递至脑内皮细胞影响（将在 AIM 3 中确定的）AJP、TJP 和/或 MMP 的表达。