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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：
9899915
负责人：
Neetu Gupta
金额：
$ 37.97万
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 2022-03-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9899915
关键词：
Affect Age American Anti-Inflammatory Agents 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 Measures Mediating Mediator of activation protein Membrane Microscopy Modeling Molecular Molecular Biology Molecular Target Monitor Mus Myeloid Cells Output Pain Pathogenesis Pathogenicity Pathologic Pathology Pathway interactions Patients 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 ds-DNA effective therapy experimental analysis experimental study ezrin genome wide association study human disease immunopathology in vivo innovation insight live cell imaging lymphoid organ migration mouse model new therapeutic target next generation sequencing novel novel strategies peripheral lymphoid organ 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.

项目概要系统性红斑狼疮 (SLE) 是一种以自身抗体为特征的免疫系统疾病产生、过度活跃的 B 细胞抗原受体 (BCR) 信号传导和 B 细胞高反应性；然而，调节异常 B 细胞功能的机制尚不清楚。蛋白质的研究和 SLE 中驱动 BCR 信号传导、B 细胞过度激活和自身抗体产生的过程应该提供机制见解并导致开发更有效的疗法。 B细胞活化得以保持受到有效抑制途径的控制，该途径的关键组成部分是 Src 家族激酶 Lyn。人类 GWAS 研究表明 Lyn 低表达与 SLE 发病率之间存在密切相关。小鼠 Lyn 基因缺失后，失去外周耐受性，并表现出与人类相关的所有症状 SLE，包括 BCR 信号传导加剧、B 细胞过度激活、血清自身抗体水平升高，以及肾小球肾炎。因此，Lyn-/- 小鼠代表了研究分子生物学的临床相关模型。 SLE 中 B 细胞自身免疫的调节。我们之前报道过膜-细胞骨架连接子 Ezrin 蛋白通过动态磷酸化调节 B 细胞功能的多个方面去磷酸化。有趣的是，我们观察到埃兹蛋白在 Lyn-/- B 细胞中过度磷酸化，并且 Lyn-/-小鼠B细胞中的ezrin条件性缺失导致B细胞活化显着降低，分化、自身抗体产生和免疫复合物在肾脏中的沉积。我们的数据表明在 Lyn 缺失的情况下，ezrin 是 B 细胞过度激活的重要介质，因此是一种潜在的分子目标。我们假设埃兹蛋白通过促进分子水平促进 Lyn-/- 小鼠的 B 细胞发病机制以及依赖膜细胞骨架重组的细胞过程。我们的具体目标是：(1) 研究ezrin缺失对体内免疫病理学的影响，(2)确定ezrin缺失的效果 (3)检测ezrin缺失对BCR组织和B细胞的影响体外激活。我们将利用遗传、免疫学、蛋白质组学、分子生物学和高分辨率活细胞成像技术来实现我们的目标。我们期望这些研究的结果将确定 Lyn-/- 小鼠在不同疾病阶段因埃兹蛋白缺失而改变的 SLE 病理特征确定 ezrin 是否通过增强生发中心 B 细胞来促进 Lyn-/- 小鼠的自身免疫反应，并揭示埃兹蛋白促进 B 细胞过度活跃的空间和分子机制在 Lyn 不在场的情况下做出反应。意义和影响：我们预计创新的小鼠模型和这里提出的实验分析将建立埃兹蛋白依赖性膜细胞骨架重塑作为 Lyn 缺陷引起的调节 B 细胞自身免疫的新模式。此外，我们的结果将为未来评估埃兹蛋白在其他小鼠模型疾病发病机制中的作用的研究设计提供信息 SLE 以及 SLE 患者。最终，我们的研究应该能够找到新的途径 SLE 的治疗进展。