Pathogenic Astrocyte Populations in EAE and MS

项目摘要 多发性硬化症（MS）是中枢神经系统（CNS）的自身免疫性疾病， 是年轻人神经系统残疾的主要原因。星形胶质细胞、小胶质细胞和单核细胞起重要作用 在MS及其模型，实验性自身免疫性脑脊髓炎（EAE）中的作用，但调节机制， 人们对其活动了解甚少。对星形胶质细胞和小胶质细胞调节的研究可能会发现 在MS中的发病机制和治疗靶点，特别是对于疾病的进展阶段。 我们的长期目标是开发治疗方法来限制MS中星形胶质细胞的致病活动。 在我们的研究中，我们进行了以下初步观察：1）SigmaR 1-IRE 1a信号转导激活了 星形胶质细胞中的转录因子XBP 1，促进小胶质细胞活化，单核细胞募集到CNS， EAE期间的疾病病理学; 2）星形胶质细胞特异性XBP 1敲低改善EAE; 3）在EAE期间， EAE和MS中的星形胶质细胞亚群; 4）星形胶质细胞中的XBP 1活化与VEGF-B增加相关 5）小胶质细胞和CNS募集的单核细胞在EAE期间产生VEGF-B;和6）由EAE产生的VEGF-B。 小胶质细胞促进星形胶质细胞促炎活性。我们假设活跃的XBP 1（XBP 1 s）驱动一个 MS和EAE中的致病性星形胶质细胞亚群（XBP 1 s+星形胶质细胞），由小胶质细胞控制， 单核细胞产生的VEGF-B。因此，我们建议研究SigmaR 1-IRE 1a-XBP 1信号转导在 星形胶质细胞在EAE和MS中的作用及其作为治疗靶点的潜力。我们的具体目标是： 特定目的1：XBP 1激活是否定义了致病性星形胶质细胞的一个子集？ 我们提出：1）通过核酸聚焦询问细胞来表征EAE中的XBP 1 s+星形胶质细胞 检测和测序（FIND-seq）是我们开发的用于深入研究细胞亚群的方法，以及2） 生成XBP 1 s+星形胶质细胞的定位、调节和细胞相互作用的时空图， 使用MERFISH（多重误差稳健荧光原位杂交）检测EAE和MS中的其他细胞亚群。 具体目标2：小胶质细胞和单核细胞如何控制XBP 1 s+星形胶质细胞？ 我们的目的是：1）明确小胶质细胞和单核细胞产生的VEGF-B在调控XBP 1 s+表达中的作用。 和其他星形胶质细胞亚群，以及2）通过NICHE-seq鉴定参与对照的其他途径， EAE期间小胶质细胞和单核细胞对XBP 1 s+和其他星形胶质细胞亚群的影响。 特定目的3：SigmaR 1是调节CNS炎症的治疗靶点吗？ 本研究拟：1）评价临床级CNS渗透剂SigmaR 1拮抗剂S1 RA的治疗价值 2）确定S1 RA对EAE中CNS中的XBP 1 s+星形胶质细胞和其他细胞亚群的作用。 总之，该项目研究了一种新的星形胶质细胞亚群，即 控制它，它的分布和整个CNS的细胞相互作用，以及它作为MS治疗靶点的潜力。

PROJECT SUMMARY Multiple Sclerosis (MS) is an autoimmune disease of the central nervous system (CNS) that constitutes the leading cause of neurologic disability in young adults. Astrocytes, microglia and monocytes play important roles in MS and its model, experimental autoimmune encephalomyelitis (EAE), but the mechanisms that regulate their activity are poorly understood. The study of astrocyte and microglia regulation may identify mechanisms of pathogenesis and therapeutic targets in MS, particularly for the progressive phase of the disease. Our long-term goal is to develop therapies to limit astrocyte pathogenic activities in MS. During the course of our studies we made the following preliminary observations: 1) SigmaR1-IRE1a signaling activates the transcription factor XBP1 in astrocytes, promoting microglial activation, monocyte recruitment to the CNS and disease pathology during EAE; 2) Astrocyte-specific XBP1 knockdown ameliorates EAE; 3) XBP1 is activated in an astrocyte subset in EAE and MS; 4) XBP1 activation in astrocytes is associated to increased VEGF-B signaling 5) Microglia and CNS-recruited monocytes produce VEGF-B during EAE; and 6) VEGF-B produced by microglia boost astrocyte pro-inflammatory activities. We hypothesize that active XBP1 (XBP1s) drives a pathogenic astrocyte subset (XBP1s+ astrocytes) in MS and EAE, which is controlled by microglia- and monocyte-produced VEGF-B. Thus, we propose to study the role of SigmaR1-IRE1a-XBP1 signaling in astrocytes in EAE and MS, and its potential as a therapeutic target. Our specific aims are: SPECIFIC AIM 1: Does XBP1 activation define a subset of pathogenic astrocytes? We propose to: 1) Characterize XBP1s+ astrocytes in EAE using Focused Interrogation of cells by Nucleic acid Detection and Sequencing (FIND-seq) a method, which we developed to study cell subsets in-depth, and 2) Generate a spatiotemporal map of the localization, regulation and cell interactions of XBP1s+ astrocytes and other cell subsets in EAE and MS using MERFISH (Multiplexed error robust fluorescence in situ hybridization). SPECIFIC AIM 2: How do microglia and monocytes control XBP1s+ astrocytes? We propose to: 1) Define the role of VEGF-B produced by microglia and monocytes on the control of XBP1s+ and other astrocyte subsets during EAE, and 2) Identify by NICHE-seq additional pathways involved in the control of XBP1s+ and other astrocyte subsets by microglia and monocytes during EAE. SPECIFIC AIM 3: Is SigmaR1 a therapeutic target to modulate CNS inflammation? We propose to: 1) Evaluate the therapeutic value of the clinical-grade CNS penetrant SigmaR1 antagonist S1RA on EAE, and 2) Define the effects of S1RA on XBP1s+ astrocytes, and other cell subsets in the CNS in EAE. IN SUMMARY, this project studies a novel astrocyte subset, the molecular and cellular mechanisms that control it, its distribution and cell interactions throughout the CNS, and its potential as a therapeutic target in MS.