Therapeutic Intervention of the JAK/STAT Pathway for Neuroinflammation

描述(申请人提供)：多发性硬化(MS)的特点是中枢神经系统局灶性炎症浸润性病变，脱髓鞘病变和轴突损伤，导致神经功能障碍。先天性免疫系统和获得性免疫系统的细胞参与了MS的发病。MS的特征还包括产生激活免疫细胞的细胞因子，包括干扰素-γ、IL-6、GM-CSF、IL-12和IL-23。JAK/STAT通路被细胞因子用于信号传递，对免疫反应的发展、调节和终止至关重要。在之前的资助阶段，我们建立了实验性自身免疫性脑脊髓炎(EAE)模型，在该模型中，JAK/STAT通路在髓系细胞中异常激活，对Th1和Th17细胞的分化具有功能影响。该模型表现为非典型EAE的非分辨形式。在这个JAK/STAT通路高度激活的非典型模型中，我们证明了JAK/STAT通路的抑制剂AZD1480抑制了疾病的严重性，阻止了免疫细胞进入中枢神经系统，抑制了Th1和Th17细胞的分化，减少了STAT的激活，并减少了细胞因子/趋化因子的表达。此外，我们还在其他四种EAE模型(经典、复发缓解(RR)、过继转移Th1或Th17细胞)上测试了AZD1480，并观察到了显著的临床疗效。另一种JAK/STAT抑制剂AZD5776也可以抑制EAE的临床症状。我们假设JAK/STAT通路的不适当激活促进了先天性和获得性免疫系统细胞的异常反应，导致了MS中看到的神经炎症，并且对该通路的治疗干预将改变MS的进展。在这一修订的、竞争性的更新中，我们将在五个EAE模型中评估两种不同的JAK抑制剂AZD1480和AZD5776。AZD1480是JAK1和JAK2的抑制剂，AZD5776抑制JAK1。在目标1中，将检测靶向JAK/STAT通路在活动期EAE(经典的、非典型的、RR)中的治疗效果。我们将评估1)哪些JAK/STAT参与了疾病的发病机制；2)在哪些细胞类型(S)(CD_4+T细胞、巨噬细胞、小胶质细胞、DC)中JAK/STAT通路的激活是有害的；以及3)JAK抑制剂治疗益处的分子基础。在目标2中，将测试JAK/STAT通路在调节Th1和Th17细胞致病潜力中的作用。Th1和Th17细胞均具有诱导中枢神经系统自身免疫的能力，但致病机制不同。我们的初步结果表明，AZD1480对Th1诱导的和Th17诱导的EAE都有有效的抑制作用。我们将评估在MOG免疫的背景下，AZD1480/AZD5776的体内治疗如何调节Th1和Th17细胞的发育程序和/或致病性。在目标3中，将研究JAK抑制剂AZD1480和AZD5776调节免疫细胞功能的机制。从JAK抑制剂处理过的幼小鼠获得的巨噬细胞和DC将被评估其抗原提呈能力、分化为促炎或抗炎表型以及潜在的神经保护特性。来自JAK抑制剂治疗的小鼠的CD4+T细胞将被检测其随后分化为致病和/或保护性T细胞亚群的能力。这些研究将为最终在人类MS中测试JAK/STAT通路的抑制剂奠定必要的临床前基础。

DESCRIPTION (provided by applicant): Multiple Sclerosis (MS) is characterized by focal inflammatory infiltrates of the CNS, demyelinating lesions and axonal damage, leading to neurologic dysfunction. Cells of the innate and adaptive immune system are involved in MS pathogenesis. MS is also characterized by production of cytokines that activate immune cells, including IFN-γ, IL-6, GM-CSF, IL-12 and IL-23. The JAK/STAT pathway is used by cytokines for signaling, and is critical for the development, regulation and termination of immune responses. In the previous funding period, we developed a model of Experimental Autoimmune Encephalomyelitis (EAE) in which the JAK/STAT pathway is aberrantly activated in myeloid cells, with functional consequences for Th1 and Th17 cell differentiation. This model presents as a non-resolving form of atypical EAE. In this atypical model with heightened activation of the JAK/STAT pathway, we demonstrate that AZD1480, an inhibitor of the JAK/STAT pathway, suppresses disease severity, prevents entry of immune cells into the CNS, suppresses differentiation of Th1 and Th17 cells, decreases STAT activation, and reduces expression of cytokines/chemokines. Furthermore, we have tested AZD1480 in four other EAE models (Classical, Relapsing-Remitting (RR), Adoptive Transfer of Th1 or Th17 cells) and observed striking clinical efficacy. Another JAK/STAT inhibitor, AZD5776, also inhibits EAE clinical symptoms. We hypothesize that inappropriate activation of the JAK/STAT pathway promotes aberrant responses of cells of the innate and adaptive immune systems, leading to the neuroinflammation seen in MS, and that therapeutic intervention of this pathway will alter the progression of MS. In this revised, competing renewal, we will evaluate two distinct JAK inhibitors, AZD1480 and AZD5776, in five EAE models. AZD1480 is a JAK1 and JAK2 inhibitor, and AZD5776 inhibits JAK1. In Aim 1, the therapeutic efficacy of targeting the JAK/STAT pathway in active EAE (classical, atypical, RR) will be examined. We will evaluate 1) which JAKs/STATs are involved in disease pathogenesis; 2) in which cell type(s) (CD4+ T-cells, macrophages, microglia, DCs) activation of the JAK/STAT pathway is detrimental; and 3) the molecular basis for the therapeutic benefit of the JAK inhibitors. In Aim 2, the role of the JAK/STAT pathway in regulating the pathogenic potential of Th1 and Th17 cells will be tested. Both Th1 and Th17 cells have the capacity to induce CNS autoimmunity, but have differential pathogenic mechanisms. Our preliminary results indicate that AZD1480 is effective in inhibiting both Th1-induced and Th17-induced EAE. We will assess how in vivo treatment with AZD1480/AZD5776 in the context of MOG-immunization regulates the developmental program and/or pathogenicity of Th1 and Th17 cells. In Aim 3, the mechanism by which the JAK inhibitors AZD1480 and AZD5776 regulate immune cell function will be examined. Macrophages and DCs obtained from naive mice treated with JAK inhibitors will be evaluated for their antigen presentation capability, polarization into proinflammatory or anti-inflammatory phenotypes, and potential neuroprotective properties. CD4+ T-cells derived from JAK inhibitor treated mice will be examined for their subsequent ability to differentiate into pathogenic and/or protective T-cell subsets. These studies will establish the pre-clinical foundation necessary to ultimately test inhibitors of the JAK/STAT pathway in human MS.