Pathogenic Astrocyte Populations in EAE and MS

项目总结 多发性硬化症(MS)是一种中枢神经系统(CNS)的自身免疫性疾病， 这是导致年轻人神经功能障碍的主要原因。星形胶质细胞、小胶质细胞和单核细胞发挥重要作用 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 人们对它们的活动知之甚少。对星形胶质细胞和小胶质细胞调节的研究可能确定脑出血的机制。 多发性硬化症的发病机制和治疗靶点，特别是疾病的进展期。 我们的长期目标是开发治疗方法，以限制多发性硬化症期间星形胶质细胞的致病活动。 在我们的研究中，我们做了以下初步观察：1)SigmaR1-IRE1a信号激活 转录因子XBP1在星形胶质细胞中的作用，促进小胶质细胞的激活，单核细胞募集到中枢和 EAE期间的疾病病理；2)星形胶质细胞特异性XBP1基因敲除改善EAE；3)XBP1在 EAE和MS中的一个星形胶质细胞亚群；4)星形胶质细胞中XBP1的激活与VEGF-B的增加有关 信号5)小胶质细胞和中枢神经系统募集的单核细胞在EAE过程中产生VEGF-B；以及6)由 小胶质细胞增强星形胶质细胞的促炎活性。我们假设活动的XBP1(XBP1)驱动一个 MS和EAE中致病星形胶质细胞亚群(XBP1s+星形胶质细胞)，受小胶质细胞和 单核细胞产生的血管内皮生长因子-B因此，我们建议研究SigmaR1-IRE1a-XBP1信号在 EAE和MS中的星形胶质细胞及其作为治疗靶点的潜力。我们的具体目标是： 特定目的1：XBP1激活是否定义了致病星形胶质细胞的一个子集？ 我们建议：1)利用核酸对细胞的聚焦询问来鉴定EAE中XBP1s+星形胶质细胞 检测和测序(Find-Seq)是我们开发的一种深入研究细胞亚集的方法，以及2) 生成XBP1s+星形胶质细胞的定位、调节和细胞相互作用的时空图 EAE和MS中的其他细胞亚群使用MERFISH(多重错误稳健荧光原位杂交)。 特定目的2：小胶质细胞和单核细胞如何控制XBP1s+星形胶质细胞？ 我们建议：1)明确小胶质细胞和单核细胞产生的血管内皮生长因子-B在XBP1s+调控中的作用 和其他星形胶质细胞亚群，以及2)通过NICE-SEQ识别参与控制的其他途径 在EAE期间，小胶质细胞和单核细胞对XBP1s+和其他星形胶质细胞亚群的表达。 特定目标3：SigmaR1是调节中枢神经系统炎症的治疗靶点吗？ 我们建议：1)评估临床级别中枢神经系统渗透剂SigmaR1拮抗剂S1RA的治疗价值 以及2)确定S1RA对EAE患者中枢神经系统XBP1s+星形胶质细胞和其他细胞亚群的影响。 综上所述，该项目研究了一种新的星形胶质细胞亚群，即 控制它，它在整个中枢神经系统的分布和细胞相互作用，以及它作为MS的治疗靶点的潜力。

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.