Role of the neurovascular molecule Wnt in regulating CNS inflammatory responses

项目总结/摘要 我们实验室的目标是研究先天细胞的免疫调节，以治疗和解决/修复 中枢神经系统（CNS）炎性疾病。在神经炎症过程中， CNS和免疫系统影响由浸润性和驻留免疫介导的病理反应， 细胞特别是，在多发性硬化症（MS），骨髓细胞中发现丰富的病变。这些 髓样抗原提呈细胞（APC）具有吞噬髓鞘碎片、释放神经毒性因子 并促进CNS中T细胞的扩增和极化。然而，它们也可以对抗 炎症和促进修复。CNS环境调节髓系细胞的确切机制 APC在神经炎症中的功能仍然不清楚。 实验性自身免疫性脑脊髓炎（EAE）中与MS样病变相关的转录本分析， MS的动物模型，揭示了与Wnt/β-连环蛋白途径相关的基因的显著富集 与非病变区相比。Wnt蛋白与细胞表面受体Frizzled（Fzd）的结合抑制了 糖原合成酶激酶3b（GSK 3b）和b-连环蛋白磷酸化，使b-连环蛋白易位到 细胞核并激活Wnt靶基因的转录。已经证明，树突状细胞中的Wnt信号转导 细胞（DC）在调节炎症反应与调节反应之间的平衡中起着核心作用。 直觉GSK 3b激酶的阻断显示单核细胞增加IL-10的产生，同时抑制单核细胞的增殖。 促炎细胞因子的释放。此外，我们的初步结果表明， 在Wnt/b-连环蛋白通路中，PD-L1和PD-L2在人和小鼠骨髓细胞上的表达增加， 而IL-1b、IL-6、IL-12和IL-23降低。显著地，在EAE中，Wnt激动剂治疗降低了 慢性和复发缓解型EAE的临床严重程度。 Wnt蛋白质在CNS中由脑内皮细胞（BBB-EC）和星形胶质细胞天然表达，并且在CNS中表达。 在神经炎症中上调。这些细胞形成神经血管单位（NVU），这是一种结构， 外周和CNS之间的界面，因此直接暴露于外周和 CNS驱动的炎症。我们推测，在神经血管水平的炎症信号诱导Wnt 由EC和星形胶质细胞产生，这将调节髓样APC的功能并促进抗- 支持修复和限制神经病理学的炎症反应。使用体外和体内 我们的目标是了解Wnt配体如何影响CNS中的免疫应答，并确定 操纵它以调节骨髓细胞功能从而减少CNS炎症反应的可能性 刺激修复机制

PROJECT SUMMARY/ABSTRACT The goal of our lab is to investigate immune regulation by innate cells for the treatment and resolution/repair of central nervous system (CNS) inflammatory diseases. During neuroinflammation the concerted actions of the CNS and the immune system affect the pathological responses mediated by infiltrating and resident immune cells. In particular, during multiple sclerosis (MS), myeloid cells are found in abundance within lesions. These myeloid antigen-presenting cells (APCs) have the ability to phagocytose myelin debris, release neurotoxic factors and promote the expansion and polarization of T cells in the CNS. However, they can also antagonize inflammation and promote repair. The exact mechanism(s) by which the CNS environment regulates myeloid APCs function during neuroinflammation remains ill defined. Analysis of the transcripts associated with MS-like lesions in experimental autoimmune encephalomyelitis (EAE), an animal model of MS, revealed a significant enrichment of genes associated with the Wnt/b-catenin pathway as compared to non-lesioned areas. Binding of Wnt proteins to the cell surface receptor Frizzled (Fzd) inhibits glycogen synthase kinase 3b (GSK3b) and b-catenin phosphorylation, allowing b-catenin translocation to the nucleus and activates transcription of Wnt target genes. It has been demonstrated that Wnt signaling in dendritic cells (DCs) plays a central role in regulating the balance between inflammatory vs. regulatory responses in the gut. Blockade of GSK3b kinase was shown to increase IL-10 production by monocytes while suppressing the release of pro-inflammatory cytokines. In addition, our preliminary results demonstrate that following activation of the Wnt/b-catenin pathway, PD-L1 and PD-L2 expression were increased on human and mouse myeloid cells, while IL-1b, IL-6, IL-12 and IL-23 were reduced. Significantly, in EAE, Wnt agonist treatment decreased the clinical severity of chronic and relapsing-remitting EAE. Wnt proteins are naturally expressed in the CNS by brain endothelial cells (BBB-ECs) and astrocytes, and are upregulated during neuroinflammation. These cells make the neurovascular unit (NVU), a structure serving as an interface between the periphery and the CNS and hence directly exposed to the effects of peripheral and CNS driven inflammation. We hypothesize that inflammatory signals at the neurovascular level induce Wnt production by ECs and astroglial cells, which will regulate myeloid APCs function and promote anti- inflammatory responses that support repair and limit neuropathology. Using in vitro and in vivo approaches, our goal is to understand how Wnt ligands affect the immune response in the CNS and to determine the possibility to manipulate it in order to regulate myeloid cell function to reduce CNS-inflammatory responses and stimulate the repair mechanism.