Innate Immune Activation in Autoimmune Myopathy

项目摘要/摘要 特发性炎症性肌病(IIM)代表一组全身性自身免疫性疾病 肌肉和肌肉外器官是免疫中介破坏的目标。我们之前已经 建立组氨酰-tRNA合成酶(HRS)诱导的涉及MyD88依赖的肌炎模型 以Toll样受体2和4(TLR2、TLR4)为特征的先天免疫信号通路。考虑到突出的 这些TLRs在我们的HRS诱导的肌炎模型中的作用，我们假设 下游转录调节因子NF-κB也是各种炎症级联反应的最终责任者 作为非免疫途径促进该系统中的肌肉功能障碍-有效地连接HRS诱导的 肌炎/IIM合并其他疾病(包括肌营养不良和脓毒症-以及创伤/缺血- 诱导的肌病)，在这种情况下，核因子-κB的失调导致肌肉炎症、肌肉变性、 以及受损的再生潜能。通过一系列体外培养系统和体内免疫 涉及缺乏MyD88依赖的信号通路关键组件的基因敲除小鼠的策略，我们 将系统地研究HRS诱导的TLR信号和NF-κB激活对T细胞迁移的影响， T细胞激活，肌肉无力。而特定目标1将专注于HRS诱导的T细胞变化 血管内皮细胞的功能和TLR介导的激活(导致靶细胞的淋巴细胞渗透) 器官)，特异性目标2将定义高铁诱导的肌肉中NF-κB激活的直接和间接途径 组织通过体外成肌细胞刺激分析以及其他免疫研究，重点是 肌肉炎症、核因子-κB激活与肌肉体内外参数的相关性 软弱。补充体内评估工具，包括核磁共振和使用核转录因子-κB-荧光素酶转基因 小鼠将进一步确定HRS介导的NF-κB激活和肌肉功能障碍之间的关系， 为针对特定目标的比较核转录因子-κB抑制的实验试验提供基础。 这些研究将阐明先天免疫在IIM发病机制中的作用，补充更多 抗原特异性、适应性免疫识别和识别治疗靶点的传统范例 可能与一系列人类炎症性肌肉疾病有关。

PROJECT SUMMARY/ABSTRACT The idiopathic inflammatory myopathies (IIMs) represent a group of systemic autoimmune disorders in which muscle and extra-muscular organs are targeted for immune-mediated destruction. We have previously established a model of histidyl-tRNA synthetase (HRS)-induced myositis that involves MyD88-dependent innate immune signaling pathways featuring Toll-like receptors 2 and 4 (TLR2, TLR4). Given the prominent role of these TLRs in our model of HRS-induced myositis, we hypothesize that heightened activation of the downstream transcription regulator NF-κB is ultimately responsible for various inflammatory cascades as well as non-immune pathways promoting muscle dysfunction in this system—effectively linking HRS-induced myositis/IIM with other disorders (including muscular dystrophy as well as sepsis- and trauma/ischemia- induced myopathies) in which NF-κB dysregulation contributes to muscle inflammation, muscle degeneration, and impaired regenerative potential. Through a series of in vitro culture systems and in vivo immunization strategies involving knockout mice lacking critical components of MyD88-dependent signaling pathways, we will systematically examine the impact of HRS-induced TLR signaling and NF-κB activation on T cell migration, T cell activation, and muscle weakness. While Specific Aim 1 will focus on HRS-induced changes in T cell function and TLR-mediated activation of vascular endothelium (leading to lymphocytic infiltration of target organs), Specific Aim 2 will define direct and indirect pathways of HRS-induced NF-κB activation in muscle tissue through in vitro myoblast stimulation assays as well as additional immunization studies focusing on correlations between muscle inflammation, NF-κB activation, and in vivo/ex vivo parameters of muscle weakness. Complementary in vivo assessment tools including MRI and the use of NF-κB-luciferase transgenic mice will further define the relationship between HRS-mediated NF-κB activation and muscle dysfunction, providing the foundation for experimental trials of comparative NF-κB inhibition in Specific Aim 3. Collectively, these studies will elucidate the contribution of innate immunity to the pathogenesis of IIM, supplementing more traditional paradigms of antigen-specific, adaptive immune recognition and identifying therapeutic targets that are potentially relevant to a range of human inflammatory muscle diseases.