Regulation of B cell activation in lupus

狼疮中 B 细胞活化的调节

基本信息

批准号：
9242562
负责人：
Neetu Gupta
金额：
$ 38.05万
依托单位：
CLEVELAND CLINIC LERNER COM-CWRU
依托单位国家：
美国
项目类别：
财政年份：
2016
资助国家：
美国
起止时间：
2016-04-01 至 2021-03-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9242562
关键词：
Affect Age American Anti-Inflammatory Agents Anti-inflammatory Antibody Formation Antigen-Antibody Complex Autoantibodies Autoimmune Diseases Autoimmune Process Autoimmunity B cell differentiation B-Cell Activation B-Lymphocytes Biological Assay Body part Bone Marrow Bone Marrow Cells Cell membrane Cell physiology Cellular Infiltration Cellular biology Chimera organism Clonality Complement Cytoskeletal Modeling Cytoskeleton Data Deposition Development Disease Disease Progression Enzyme-Linked Immunosorbent Assay Exhibits Flow Cytometry Frequencies Functional disorder Future Generations Genetic Glomerulonephritis Homing Human Hyperactive behavior Image Imaging Techniques Immune System Diseases Immunoglobulin Class Switching Immunoglobulin Somatic Hypermutation Immunohistochemistry Immunologics In Vitro Incidence Inflammation Investigation Kidney Kidney Glomerulus Knock-out Lead Life Ligands Lupus Lymphoid Measures Mediating Mediator of activation protein Membrane Microscopy Modeling Molecular Molecular Biology Molecular Target Monitor Mus Myeloid Cells Organ Output Pain Pathogenesis Pathogenicity Pathologic Pathology Pathway interactions Patients Peripheral Phosphorylation Plasma Cells Population Process Production Property Protein Dephosphorylation Proteins Proteomics Reaction Receptor Signaling Receptors, Antigen, B-Cell Regulation Reporting Research Resolution Role Serum Signal Pathway Signal Transduction Structure of germinal center of lymph node Syndrome Systemic Lupus Erythematosus T-Lymphocyte Testing Western Blotting associated symptom cell motility clinically relevant crosslink cytokine design differentiated B cell ds-DNA effective therapy experimental analysis experimental study ezrin genome wide association study human disease immunopathology in vivo innovation insight live cell imaging migration mouse model new therapeutic target next generation sequencing novel novel strategies peripheral tolerance response small molecule inhibitor src-Family Kinases therapeutic development treatment strategy

项目摘要

PROJECT SUMMARY Systemic lupus erythematosus (SLE) is a disorder of the immune system that is characterized by autoantibody production, hyperactive B cell antigen receptor (BCR) signaling and B cell hyperresponsiveness; however, the mechanisms that regulate aberrant B cell function are poorly understood. Investigation of proteins and processes that drive BCR signaling, B cell hyperactivation and autoantibody production in SLE should offer mechanistic insights and lead to development of more effective therapies. B cell activation is kept under check by a potent inhibitory pathway, a key component of which is the Src family kinase Lyn. Human GWAS studies have shown a strong association between lower expression of Lyn and incidence of SLE. Mice with genetic deletion of Lyn lose peripheral tolerance and display all the symptoms associated with human SLE, including exacerbated BCR signaling, B cell hyperactivation, high levels of serum autoantibodies, and glomerulonephritis. Therefore, Lyn-/- mice represent a clinically relevant model to investigate the molecular regulation of B cell autoimmunity in SLE. We have previously reported that the membrane-cytoskeleton linker protein Ezrin regulates multiple facets of B cell function by undergoing dynamic phosphorylation- dephosphorylation. Interestingly, we observed that ezrin is hyperphosphorylated in Lyn-/- B cells, and that conditional deletion of ezrin in B cells of Lyn-/- mice leads to a significant decrease in B cell activation, differentiation, autoantibody production and immune complex deposition in the kidneys. Our data suggest that ezrin is an important mediator of B cell hyperactivation in the absence of Lyn, and thus a potential molecular target. We hypothesize that ezrin facilitates B cell pathogenesis in Lyn-/- mice by promoting molecular and cellular processes that rely on membrane-cytoskeletal reorganization. Our specific aims are, (1) to investigate the impact of ezrin deletion on immunopathology in vivo, (2) to determine the effect of ezrin deletion on B cell differentiation in vivo, and (3) to examine the effect of ezrin deletion on BCR organization and B cell activation in vitro. We will employ genetic, immunological, proteomic, molecular biology, and high-resolution live-cell imaging techniques to accomplish our aims. We expect that the results of these studies will identify the pathological features of SLE that are altered by loss of ezrin in Lyn-/- mice at different stages of disease progression, ascertain if ezrin promotes autoimmunity in Lyn-/- mice by enhancing germinal center B cell response, and reveal the spatial and molecular mechanisms employed by ezrin to facilitate hyperactive B cell responses in the absence of Lyn. Significance & Impact: We anticipate that the innovative mouse models and experimental analyses proposed here will establish ezrin-dependent membrane-cytoskeletal remodeling as a novel mode of regulating B cell autoimmunity arising from the deficiency of Lyn. Moreover, our results will inform the design of future studies assessing the role of ezrin in disease pathogenesis in other mouse models of SLE, as well as in SLE patients. Ultimately, our studies should lead to identification of new avenues for therapeutic development in SLE.

项目摘要全身性红斑狼疮（SLE）是免疫系统的疾病，其特征是自身抗体生产，多动B细胞抗原受体（BCR）信号传导和B细胞高反应性；但是，调节异常B细胞功能的机制知之甚少。蛋白质和驱动BCR信号传导，B细胞过度激活和自身抗体产生的过程应应提供机械洞察力并导致开发更有效的疗法。保留B细胞激活在有效的抑制途径检查下，其关键成分是SRC家族激酶Lyn。人类 GWAS研究表明，LYN的较低表达与SLE的发病率之间存在密切的关联。老鼠 lyn的遗传缺失失去外周耐受性，并显示与人有关的所有症状 SLE，包括恶化的BCR信号，B细胞过度激活，高水平的血清自身抗体和肾小球肾炎。因此，lyn - / - 小鼠代表了研究分子的临床相关模型 SLE中B细胞自身免疫的调节。我们以前已经报道了膜细胞骨架接头蛋白Ezrin通过进行动态磷酸化 - 调节B细胞功能的多个方面 - 去磷酸化。有趣的是，我们观察到Ezrin在Lyn - / - B细胞中被过度磷酸化，并且 lyn - / - 小鼠B细胞中埃兹林的条件缺失导致B细胞激活显着降低，肾脏中的分化，自身抗体产生和免疫复合物沉积。我们的数据表明在没有Lyn的情况下，Ezrin是B细胞过度激活的重要介质，因此有潜在的分子目标。我们假设Ezrin通过促进分子来促进Lyn - / - 小鼠中B细胞发病机理以及依赖膜细胞骨架重组的细胞过程。我们的具体目的是（1）研究Ezrin缺失对体内免疫病理学的影响，（2）确定Ezrin缺失的影响在体内B细胞分化以及（3）检查Ezrin缺失对BCR组织和B细胞的影响体外激活。我们将采用遗传，免疫学，蛋白质组学，分子生物学和高分辨率实现我们的目标的活电池成像技术。我们希望这些研究的结果将确定 SLE的病理特征因疾病不同阶段的lyn - / - 小鼠的埃兹林丧失而改变进展，确定Ezrin是否通过增强生发中心B细胞来促进Lyn - / - 小鼠中的自身免疫性响应，并揭示ezrin使用的空间和分子机制来促进过度活跃B细胞在没有林恩的情况下的反应。意义与影响：我们预计创新的鼠标模型和此处提出的实验分析将建立Ezrin依赖性膜 - 骨骼骨骼重塑作为一种调节B细胞自身免疫性的新型模式是由Lyn的缺乏引起的。而且，我们的结果将会告知评估Ezrin在其他小鼠模型中疾病发病机理中作用的未来研究的设计 SLE和SLE患者。最终，我们的研究应导致对新途径的识别 SLE的治疗发育。