Molecular Mechanism of Immune Therapy for Bone Marrow Failures

骨髓衰竭免疫治疗的分子机制

• 批准号: 7797799
• 负责人: Pearlie K Burnette
• 金额: --
• 依托单位: JAMES A. HALEY VA MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-10-01 至 2013-09-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7797799
• 关键词: Acute; Address; Adhesions; Adoptive Transfer; Aftercare; Age; Aging; Animal Model; Animals; Antigens; Antithymoglobulin; Aplastic Anemia; Applications Grants; Autoimmune Diseases; Autoimmune Process; Autoimmunity; Binding; Blood; Bone Marrow; Bone Marrow Cells; Bone Marrow Suppression; CD8B1 gene; Caring; Cell Adhesion Molecules; Cells; Cleaved cell; Clinical; Clinical Data; Clinical Research; Complex; Cyclophosphamide; Cyclosporine; Cytolysis; Data; Defect; Development; Diagnosis; Diagnostic; Disease; Disease Progression; Disease model; Dose; Dysmyelopoietic Syndromes; Effectiveness; Endothelial Cells; Equilibrium; Etiology; Event; Failure; Foundations; Funding; Future; Genetic Transcription; Goals; Hematopoiesis; Home environment; Homing; Immune; Immune response; Immune system; Immunosuppressive Agents; Immunotherapy; In Vitro; Incidence; Individual; Inflammatory; Integrin alpha4beta1; Integrins; L-Selectin; Laboratories; Large granular lymphocyte; Lead; Life Expectancy; Ligands; Link; Lymphocyte; Lymphocyte Homing Receptors; Lymphocytosis; Lymphoid; Manuscripts; Matrix Metalloproteinases; Mediating; Membrane; Metalloproteases; Methotrexate; Modeling; Molecular; Monitor; Mus; Myelogenous; Myelopoiesis; Pancytopenia; Pathogenesis; Pathology; Patients; Peripheral; Pharmaceutical Preparations; Pharmacotherapy; Population; Process; Production; Progress Reports; Publishing; Quality of life; Regulation; Rheumatoid Arthritis; Role; SELL gene; Spleen; Surface; Syndrome; System; T-Cell Activation; T-Cell Depletion; T-Lymphocyte; TNF-alpha converting enzyme; Testing; Theophylline; Therapeutic; Therapeutic immunosuppression; Time; Transgenic Mice; Tumor Necrosis Factor-alpha; Vascular Cell Adhesion Molecule-1; Vasculitis; Veterans; Work; abstracting; alpha secretase; base; bone; chronic T-cell leukemia; cytokine; cytopenia; design; effective therapy; improved; in vivo; inhibitor/antagonist; lymph nodes; meetings; migration; mouse model; novel therapeutics; pre-clinical; preclinical study; progenitor; public health relevance; receptor; research study; trafficking; treatment strategy

DESCRIPTION (provided by applicant): Abstract: Clonal diseases of large granular lymphocytes (LGL) are characterized by lymphocytosis and T cell-mediated cytopenias of the myeloid compartment. Several syndromes of T cell-mediated bone marrow failure have similar pathology including aplastic anemia (AA), paroxysmal nocturnal hemaglobinuria (PNH), and a subset of patients with Myelodysplastic Syndrome (MDS). All of these syndromes are characterized by clinical improvement with immunosuppressive therapy (IST) such as low-dose methotrexate (MTX), low- dose cyclophosphamide (CY) or cyclosporine A (CyA) and, in the case of aplastic anemia and MDS, T cell depletion with anti-thymocyte globulin (ATG). The broad long-term goal of this proposal is to improve the diagnosis and treatment of patients with LGL leukemia and these other bone marrow failure diseases. In patients with these T-cell mediated bone marrow failure syndromes, it is not clear whether the T lymphocytes become activated locally in the bone marrow against specific bone marrow antigens, or within the peripheral lymphoid system and then home to the bone marrow. The prevailing idea during the last funding period was that an antigen, presumably a common antigen on myeloid progenitors was responsible for suppression of myelopoiesis. This was thought to be due to the direct interaction between this "putative myeloid-specific antigen" and the expanded antigen-specific T cell clone. In the Progress Report, our data strongly suggests that a multi-step model of autoimmunity for this disease process based on work during the last funding period. We show in preliminary results that the lymph node homing receptor L-selectin (CD62L) is dramatically lost from CD8+ T cells in LGL leukemia patients (manuscript published in Blood 2009). The main hypothesis to be addressed in this proposal is that altered bone marrow homing is critical for LGL leukemia pathogenesis. We hypothesize that acute activation in the primary lymphoid system leads to cleavage and shedding of CD62L by the Tumor Necrosis Factor-1 Converting Enzyme (TACE), which also known as ADAM-17. This matrix metalloproteinase (MMP) cleaves not only CD62L to control the egress of T cells from the lymph node but it is also necessary for the activity of several inflammatory cytokines with known importance in LGL leukemia and other autoimmune diseases. In Specific Aim 1, we will confirm our hypothesis that loss of CD62L expression is mediated primarily by ectodomain shedding by the ADAM-17 matrix metalloproteinase. Because CD62L is a lymphoid homing receptor, we hypothesize that loss of this receptor then allows these activated T cells to exit the lymph node but loss of CD62L alone is not expected to trigger migration and colonization in the bone marrow where these cells suppress hematopoiesis. The focus of Specific Aim 2 is to determine the mechanism of bone marrow homing by T cells in LGL leukemia using an in vitro system. Homing and migration are complex events that are optimally monitored in vivo and there is no mouse model of LGL leukemia or bone marrow failure disease currently available. Moreover, the regulation of homing to the bone marrow even under normal conditions is incompletely understood. Since the antigen that activates T cells in LGL leukemia is unknown, we will use a well defined transgenic mouse model to study important aspects of bone marrow homing and hemosuppression by antigen-specific T cells. This will allow us to test the importance of CD62L, VLA-4, and ADAM-17 in vivo. Additionally, the efficacy of pharmacological inhibitors to block homing to the bone marrow will be tested to provide critical pre-clinical data for application to clinical studies in patients in the future. PUBLIC HEALTH RELEVANCE: Large granular lymphocyte (LGL) leukemia occurs primarily in older individuals and is associated with poor blood formation. Blood counts have been shown to recover in some patients after treatment with therapies that block an over active immune response. Despite the fact that patients may benefit from this form of treatment, a basic understanding of the abnormalities in the immune system is needed to understand why this form of treatment works in some patients and not others so that new and more effective therapies can be discovered. In our study, we show several important findings that possibly explain the problem in the immune system of some patients with LGL leukemia based on work from the last funding period. Our results show for the first time a model for this disease that is similar to other autoimmune diseases and lays out the foundation for a better understanding of immune defects that may lead to new therapies. We will expand on our early findings and perform experiments in the laboratory to uncover new target drug therapies based on blocking activated T cells from entering the bone marrow where they block blood formation. These studies will greatly impact the care of veterans with LGL leukemia and may also impact millions of patients with autoimmune diseases.

描述（由申请人提供）： 摘要：大颗粒淋巴细胞 (LGL) 克隆性疾病的特点是淋巴细胞增多和 T 细胞介导的髓系细胞减少。 T 细胞介导的骨髓衰竭的几种综合征具有相似的病理学，包括再生障碍性贫血 (AA)、阵发性睡眠性血红蛋白尿 (PNH) 和部分骨髓增生异常综合征 (MDS) 患者。所有这些综合征的特征都是通过免疫抑制治疗 (IST)（例如低剂量甲氨蝶呤 (MTX)、低剂量环磷酰胺 (CY) 或环孢素 A (CyA)）临床改善，对于再生障碍性贫血和 MDS，T使用抗胸腺细胞球蛋白 (ATG) 消除细胞。该提案的长期目标是改善 LGL 白血病和其他骨髓衰竭疾病患者的诊断和治疗。 在患有这些 T 细胞介导的骨髓衰竭综合征的患者中，尚不清楚 T 淋巴细胞是在骨髓中针对特定骨髓抗原局部激活，还是在外周淋巴系统内激活，然后返回骨髓。上一个资助期间的流行观点是，一种抗原（可能是骨髓祖细胞上的常见抗原）负责抑制骨髓生成。这被认为是由于这种“推定的骨髓特异性抗原”与扩展的抗原特异性 T 细胞克隆之间的直接相互作用。在进展报告中，我们的数据强烈表明，这种疾病过程的多步骤自身免疫模型基于上一个资助期间的工作。我们的初步结果表明，LGL 白血病患者的 CD8+ T 细胞中的淋巴结归巢受体 L-选择素 (CD62L) 显着丢失（手稿发表于 Blood 2009）。该提案要解决的主要假设是改变骨髓归巢对于 LGL 白血病发病机制至关重要。我们假设初级淋巴系统的急性激活导致肿瘤坏死因子-1 转换酶 (TACE)（也称为 ADAM-17）裂解和脱落 CD62L。这种基质金属蛋白酶 (MMP) 不仅可以裂解 CD62L 以控制 T 细胞从淋巴结的流出，而且对于几种在 LGL 白血病和其他自身免疫性疾病中具有重要意义的炎症细胞因子的活性也是必需的。在具体目标 1 中，我们将证实我们的假设，即 CD62L 表达的丧失主要是由 ADAM-17 基质金属蛋白酶的胞外域脱落介导的。由于 CD62L 是一种淋巴归巢受体，我们假设该受体的丢失会使这些活化的 T 细胞离开淋巴结，但单独丢失 CD62L 预计不会引发骨髓中的迁移和定植，在骨髓中这些细胞会抑制造血功能。具体目标 2 的重点是使用体外系统确定 LGL 白血病中 T 细胞归巢的机制。归巢和迁移是复杂的事件，需要在体内进行最佳监测，目前还没有 LGL 白血病或骨髓衰竭疾病的小鼠模型。此外，即使在正常条件下，归巢到骨髓的调节也不完全清楚。由于 LGL 白血病中激活 T 细胞的抗原未知，我们将使用明确的转基因小鼠模型来研究抗原特异性 T 细胞的骨髓归巢和血液抑制的重要方面。这将使我们能够在体内测试 CD62L、VLA-4 和 ADAM-17 的重要性。此外，还将测试药物抑制剂阻止归巢到骨髓的功效，以提供关键的临床前数据，以便将来应用于患者的临床研究。 公共卫生相关性： 大颗粒淋巴细胞 (LGL) 白血病主要发生在老年人中，并且与血液形成不良有关。一些患者在接受阻止过度活跃的免疫反应的治疗后，血细胞计数已被证明可以恢复。尽管患者可能受益于这种治疗形式，但仍需要对免疫系统异常有基本的了解，以了解为什么这种治疗形式对某些患者有效，而对其他患者无效，以便发现新的更有效的疗法。在我们的研究中，我们根据上一个资助期的工作，展示了一些重要的发现，这些发现可能解释了一些 LGL 白血病患者的免疫系统问题。我们的研究结果首次展示了这种疾病的模型，该模型与其他自身免疫性疾病相似，并为更好地了解可能导致新疗法的免疫缺陷奠定了基础。我们将扩展我们的早期发现，并在实验室进行实验，以发现新的靶向药物疗法，其基础是阻止活化的 T 细胞进入骨髓，从而阻止血液形成。这些研究将极大地影响患有 LGL 白血病的退伍军人的护理，也可能影响数百万患有自身免疫性疾病的患者。