Restoration of homeostatic microglia in CNS inflammation

项目摘要 多发性硬化（MS）是一种中枢神经系统（CNS）慢性炎症性疾病， 局部T细胞和骨髓细胞浸润导致脱髓鞘和神经功能丧失。激活 小胶质细胞和巨噬细胞是活动性或慢性MS斑块中的主要炎性细胞，它们 尽管我们对MS病理生理学的理解有所进步，但仍然存在 对先天性介导的继发性进展型MS进行最小限度的疾病修饰治疗或预防。 我们最近发现，在小胶质细胞中，TGFβ和APOE信号转导驱动的相互拮抗的通路， 指示稳态（M0）和神经变性（MGnD）表型之间的表型转换。使用 系统生物学方法，我们确定了M0-和MGnD-的主要转录和表观遗传调节因子， 小胶质细胞最后，我们揭示了TGFβ-IFNγ信号在外周血单核细胞重编程中的新作用 转化为具有M0分子特征的小胶质细胞样细胞。根据我们公布的初步数据，我们 假设调节APOE-TGFβ/IFNγ通路将恢复稳态耐受原性小胶质细胞 改善EAE。我们将在以下目标中阐述我们的假设： 目的1：通过APOE-TGFβ/IFNγ信号途径补充EAE中M0-稳态小胶质细胞 在这个目标中，我们将确定1）TGFβ/IFNγ信号转导对M0-小胶质细胞补充的影响， EAE; 2）APOE-TGFβ信号通路控制的小胶质细胞表型调控网络 3）EAE高峰期和恢复期小胶质细胞表型转换的命运图分析。 目的2：通过APOE-TGFβ/IFNγ途径重编程EAE和MS患者的单核细胞为MG样细胞 患者 在该目的中，我们将确定1）靶向Ly 6CHi单核细胞中的Apoe是否促进获得细胞因子。 M0-小胶质细胞转录程序; 2）TGFβ/IFN β介导的细胞凋亡的分子机制 Ly 6CHi单核细胞的重编程;以及3）在Ly 6CHi单核细胞中是否调节APOE-TGFβ/IFN β途径， 从MS受试者分离的CD 14 +/CD 16-单核细胞诱导M0-小胶质细胞转录程序， 作为治疗进展性MS的新方法。 成功完成将导致：1）鉴定APOE-TGFβ/IFNγ介导的分子机制 小胶质细胞和单核细胞表型调节中的信号传导，有助于发育、进展和 2）了解APOE-TGFβ/IFNγ信号转导在外周血淋巴细胞重编程中的作用， 在EAE和MS患者中，单核细胞转化为稳态小胶质细胞样细胞。

PROJECT SUMMARY Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system (CNS) characterized by focal T cell and myeloid cell infiltrates leading to demyelination and loss of neurologic function. Activated microglia and macrophages are the predominant inflammatory cells in active or chronic MS plaques, and they persist in secondary-progressive MS. Despite advances in our understanding of MS pathophysiology, there are minimal disease-modifying treatments or preventions for innate-mediated, secondary-progressive forms of MS. We recently found that mutually antagonistic pathways driven by TGFβ and APOE signaling in microglia, dictate a phenotypic switch between homeostatic (M0) and neurodegenerative (MGnD) phenotypes. Using a systems biology approach, we identified major transcriptional and epigenetic regulators of M0- and MGnD- microglia. Finally, we reveal a new role for TGFβ-IFNγ signaling in the reprogramming of peripheral monocytes into microglia-like cells with the M0-molecular signature. Based on our published and preliminary data, we hypothesize that modulating the APOE-TGFβ/IFNγ pathway will restore the homeostatic-tolerogenic microglia and ameliorate EAE. We will address our hypothesis in the following aims: Aim 1: Replenish M0-homeostatic microglia via APOE-TGFβ/IFNγ signaling in EAE In this Aim, we will determine 1) the impact of TGFβ/IFNγ signaling on the replenishment of M0-microglia in EAE; 2) the regulatory networks controlled by APOE-TGFβ signaling underlying microglia phenotype regulation in EAE; and 3) fate-map analysis of microglia phenotype switch during peak and recovery stage of EAE. Aim 2: Reprogram monocytes into MG-like cells via APOE-TGFβ/IFNγ pathway in EAE and from MS patients In this Aim, we will determine 1) whether targeting Apoe in Ly6CHi monocytes facilitates the acquisition of the M0-microglial transcriptional program; 2) the molecular mechanisms underlying TGFβ/IFN-mediated reprogramming of Ly6CHi monocytes; and 3) whether modulation of the APOE-TGFβ/IFN pathway in CD14+/CD16– monocytes isolated from MS subjects induces the M0-microglial transcriptional program to serve as a novel therapeutic approach for progressive MS. Successful completion will result in: 1) identification of molecular mechanisms mediated by APOE-TGFβ/IFNγ signaling in microglia and monocyte phenotype regulation that contribute to the development, progression and resolution of EAE, and 2) understanding the role of APOE-TGFβ/IFNγ signaling in reprogramming of peripheral monocytes into homeostatic microglia-like cells in EAE and from MS patients.