Neuroimmune Molecules in Scleroderma Lung Fibrosis

 描述（由申请方提供）：硬皮病（系统性硬化症，SSc）是一种特发性自身免疫性疾病，其特征为皮肤和内脏纤维化，其中许多患者受到缺乏特异性高效治疗的间质性肺病（SSc-ILD）的影响。SSc-ILD对免疫调节剂的反应以及在某些情况下对骨髓移植的反应表明白细胞参与了疾病的发病机制。从SSc-ILD患者获得的肺组织的详细检查经常显示炎性细胞与正常和纤维化细胞外基质（ECM）并置。因此，值得注意的是，纤维细胞（一种表现出间充质特征的白细胞群体）在几项研究中已证明在SSc-ILD血液和/或肺中的蓄积增强。这些细胞的意义和调节其外观的因素在这种临床背景下仍然未知。我们实验室的已发表和初步工作表明，层粘连蛋白样神经免疫分子Netrin-1（NTN-1）在这种情况下很重要。NTN-1通过与其吸引性受体结合来刺激细胞吸引，结肠直肠癌-1（DCC-1），而细胞排斥和侵入是通过与其排斥性受体不协调-5a（UNC 5a）的相互作用来驱动的。我们使用基于脱细胞人肺的新型翻译平台探索了这些途径与SSc-ILD的相关性，以证明胶原生成白细胞的积累受人肺ECM的生物化学和机械方面的调节，并且当暴露于纤维化硬皮病肺的可消化组分时，SSc-ILD PBMC产生更多的纤维细胞。在SSc-ILD中，CD 14 lo单核细胞上NTN-1表达增加，其中其调节白细胞-基质相互作用和PBMC的TGF-β1分泌。最后，在肺纤维化博莱霉素模型中进行的研究表明，NTN-1的部分缺陷改善了纤维化的组织学和生物化学读数、TGF-β1的产生和CD 45 +ColIα1+细胞的积累，表明NTN-1中和可能是这种情况下的治疗靶点。探索这些领域有可能促进对SSc肺部受累的理解。因此，在目标1中，我们将使用标准免疫定位技术和多参数质谱细胞术来确定两个充分表征的SSc-ILD受试者纵向队列的肺和血液中先天性和适应性免疫细胞上NTN-1、DCC-1和UNC 5a的表达。在目的2中，我们使用中和抗体和病毒介导的过表达策略，结合通过与正常和SSc-ILD肺基质缀合而赋予生物活性的机械可调聚合物网络，以确定Netrin-1对纤维细胞积累的调节是否是由受体介导的与ECM组分的相互作用引起的，还是由蛋白质组成和底层底物刚度的组合影响引起的。在目标3中，我们使用具有UNC 5a和DCC-1无效突变的小鼠，以及具有NTN-1和TGF-β1细胞特异性缺失的小鼠，以确定它们对在两种不同的实验诱导的肺纤维化模型中观察到的纤维化和肺内纤维细胞积聚的贡献。

 DESCRIPTION (provided by applicant): Scleroderma (Systemic Sclerosis, SSc) is an idiopathic autoimmune disease characterized by cutaneous and visceral fibrosis in which many patients are affected by interstitial lung disease (SSc-ILD) which lacks specific, highly efficacious therapy. The response of SSc-ILD to immunomodulatory agents and in some cases bone marrow transplantation suggests involvement of leukocytes in disease pathogenesis. Detailed examination of lung tissue obtained from patients with SSc-ILD frequently reveals inflammatory cells juxtaposed with normal and fibrotic extracellular matrix (ECM). It is therefore notable that fibrocytes, a population of leukocytes displaying mesenchymal characteristics, have in several studies demonstrated enhanced accumulation in the SSc-ILD blood and/or lung. The significance of these cells and the factors regulating their appearance in this clinical context remains unknown. Published and preliminary work from our laboratory indicates the laminin-like neuroimmune molecule Netrin-1 (NTN-1) is important in this setting. NTN-1 stimulates cellular attraction via binding to its attractive receptor, Deleted in Colorectal Cancer-1 (DCC-1) while cellular repulsion and invasion is driven by interactions with its repulsive receptor, Uncoordinated-5a (UNC5a). We explored the relevance of these pathways to SSc-ILD using a novel translational platform based on decellularized human lungs to demonstrate that the accumulation of collagen-producing leukocytes is regulated by biochemical and mechanical aspects of the human lung ECM, and that SSc-ILD PBMCs produce more fibrocytes when exposed to the digestible components of the fibrotic Scleroderma lung. NTN-1 expression is increased on CD14lo monocytes in SSc-ILD where it regulates leukocyte-matrix interactions and TGF-β1 secretion by PBMCs. Last, studies performed in the bleomycin model of pulmonary fibrosis demonstrate that partial deficiency of NTN-1 ameliorates histologic and biochemical readouts of fibrosis, TGF-β1 production, and the accumulation of CD45+ColIα1+ cells, indicating that NTN-1 neutralization might be a therapeutic target in this context. Exploration of these areas has the potential to advance the understanding of lung involvement in SSc. Therefore, in Aim 1, we will use standard immunolocalization techniques and multiparametric mass cytometry to define the expression of NTN-1, DCC-1, and UNC5a on innate and adaptive immune cells in the lungs and blood of two well characterized longitudinal cohort of subjects with SSc-ILD. In Aim 2, we use neutralizing antibodies and virally mediated overexpression strategies combined with mechanically tunable polymer networks rendered bioactive through conjugation with normal and SSc-ILD lung matrix to determine whether Netrin-1's modulation of fibrocyte accumulation results from receptor mediated interactions with ECM components or from the combinatorial influence of the protein composition and stiffness of the underlying substrate. In Aim 3, we use mice with null mutations of UNC5a and DCC-1, as well as mice with cell specific deletion of NTN-1 and TGF-β1 to determine their contribution to fibrosis and intrapulmonary fibrocyte accumulation seen in two separate models of experimentally-induced lung fibrosis.