The role of secondary lymphoid organ fibroblastic cells in alloimmunity

项目摘要/摘要 异基因骨髓移植(allo-bmt)可以治疗血癌和其他疾病，但有限 由危及生命的移植物抗宿主病(GVHD)引起。在清髓处理和异基因骨髓移植后，供者- 衍生的T细胞遇到外来组织抗原和其他诱导病理性同种免疫的关键信号 和GVHD。到目前为止，我们对这些信号的理解仍然不完整。我们发现了并列的 Deltalike 1/4(Dll1/4)配体诱导的缺口信号是致死性GVHD的关键驱动因素。同种异体反应性T细胞 从脾和淋巴结中的非造血性成纤维细胞基质细胞收到Notch信号，但 而不是来自造血细胞抗原提呈细胞。Ccl19-Cre+成纤维细胞基质细胞中DLL1/4的失活 在清髓性异基因骨髓移植小鼠模型中保护受者免受致死性移植物抗宿主病。然而，它是未知的 成纤维细胞基质细胞是否仅在清髓处理后才是GVHD发病所必需的 如果它们除了提供Notch配体外，还可以作为同种异体抗原的细胞来源。整体而言 该建议的目的是研究成纤维细胞基质细胞在T细胞免疫中的作用和调节，以及 探索它们作为GVHD和其他免疫疾病治疗靶点的相关性。为了实现这一目标， 我们将在两个独立的目标中研究成纤维细胞免疫生物学的两个领域。目标1将评估如何 清髓性预适应在异基因骨髓移植中影响成纤维细胞基质细胞作为Notch配体的来源。我们 将研究不同强度的清髓调节如何调节Notch配体的表达和 成纤维细胞基质细胞亚群和其他与供者T细胞相互作用的细胞群的可及性。 我们将实时确定清髓性调节是否会改变同种异体抗原特异性T细胞的行为 以及它们与宿主成纤维细胞和造血细胞的早期相互作用。使用临床相关的小鼠同种异体- 骨髓移植模型，我们将测试成纤维细胞是否仍然是驱动移植物抗宿主病的Notch信号的关键病原源 即使在减少或没有条件反射的情况下，这也表明在更广泛的免疫方面具有关键作用。目标 2将测试成纤维细胞基质细胞在移植物抗宿主病中是否发挥同种异体抗原提呈细胞的功能。初步 有证据表明，成纤维细胞基质细胞在异基因移植后上调了其抗原提呈机制。 北京时间。我们将研究驱动这种上调的信号，并使用遗传功能丧失的方法来 检测成纤维细胞固有的MHC II类表达是否参与GVHD的发病。同时，我们将 应用活体成像研究同种异体抗原和Notch配体对早期相互作用的影响 移植物抗宿主病发病时的同种异体反应性T细胞、成纤维细胞基质细胞和其他抗原提呈细胞。我的作品 有可能发现成纤维细胞基质细胞在移植物抗宿主病中的新功能，并提示在 更广泛的免疫学背景。此外，它还将为我提供有组织的学习机会 实验免疫生物学，为我作为免疫学家和内科科学家的培训目标服务。

PROJECT SUMMARY/ABSTRACT Allogeneic bone marrow transplantation (allo-BMT) can cure blood cancers and other disorders, but is limited by life-threatening graft-versus-host-disease (GVHD). After myeloablative conditioning and allo-BMT, donor- derived T cells encounter foreign tissue antigens and other critical signals that induce pathogenic alloimmunity and GVHD. To date, our understanding of these signals remains incomplete. We discovered that juxtacrine Notch signals induced by Delta-like1/4 (Dll1/4) ligands are key drivers of lethal GVHD. Alloreactive T cells received Notch signals from non-hematopoietic fibroblastic stromal cells in the spleen and lymph nodes, but not from hematopoietic antigen-presenting cells. Dll1/4 inactivation in Ccl19-Cre+ fibroblastic stromal cells protected recipients from lethal GVHD in a mouse model of myeloablative allo-BMT. However, it is unknown whether fibroblastic stromal cells are essential for GVHD pathogenesis only after myeloablative conditioning and if they can function as a cellular source of alloantigens in addition to presenting Notch ligands. The overall goal of this proposal is to study the role and regulation of fibroblastic stromal cells in T cell immunity, as well as explore their relevance as therapeutic targets in GVHD and other immune disorders. To accomplish this goal, we will investigate two areas of fibroblastic cell immunobiology in two independent Aims. Aim 1 will assess how myeloablative conditioning affects fibroblastic stromal cells as sources of Notch ligands during allo-BMT. We will study how graded intensities of myeloablative conditioning regulate Notch ligand expression and accessibility in subsets of fibroblastic stromal cells and other cell populations that interact with donor T cells. We will determine in real-time if myeloablative conditioning changes the behavior of alloantigen-specific T cells and their early interactions with host fibroblastic and hematopoietic cells. Using clinically relevant mouse allo- BMT models, we will test if fibroblastic cells remain key pathogenic sources of Notch signals driving GVHD even with reduced or no conditioning, which would suggest key functions in broader aspects of immunity. Aim 2 will test if fibroblastic stromal cells function as alloantigen-presenting cells during GVHD. Preliminary evidence suggests that fibroblastic stromal cells upregulate their antigen presentation machinery after allo- BMT. We will investigate the signals that drive this upregulation and use genetic loss of function approaches to test if fibroblastic cell-intrinsic MHC Class II expression contributes to GVHD pathogenesis. In parallel, we will use intravital imaging to study the impact of alloantigens and Notch ligands on early interactions between alloreactive T cells, fibroblastic stromal cells and other antigen-presenting cells at the onset of GVHD. My work has the potential to uncover new functions of fibroblastic stromal cells in GVHD and to suggest a role in broader immunological contexts. In addition, it will provide me with structured learning opportunities in experimental immunobiology that serve my training goals as an immunologist and physician-scientist.