TLR7 and TLR9-directed plasma cell formation: Dissecting the molecular basis for their differential dependence on IFN-induced signals

TLR7 和 TLR9 定向浆细胞形成：剖析它们对 IFN 诱导信号的差异依赖性的分子基础

• 批准号: 10214491
• 负责人: Frances E. Lund
• 金额: $ 71.33万
• 依托单位: UNIVERSITY OF ALABAMA AT BIRMINGHAM
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-07-10 至 2025-06-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10214491
• 关键词: Activated B-Lymphocyte; Address; Adjuvant; Affect; American; Antibodies; Antibody Response; Antigens; Autoantigens; Autoimmune; Autoimmune Diseases; Autoimmunity; Automobile Driving; B cell differentiation; B-Cell Activation; B-Lymphocyte Subsets; B-Lymphocytes; Binding; Biological Models; Cell Differentiation process; Cells; Chromatin; Clinical; Data; Dependence; Development; Disease; Effector Cell; FDA approved; Financial Hardship; Future; Genes; Genetic Transcription; Goals; Health; Human; IRF1 gene; Immune response; Immune system; Immunoglobulin-Secreting Cells; Individual; Inflammation Mediators; Inflammatory; Interferon Type II; Interferon-alpha; Interferons; Interleukin-2; Intervention; JAK1 gene; Knowledge; Learning; Licensing; Ligands; Maintenance; Mediating; Mediator of activation protein; Molecular; Molecular Probes; Nuclear Translocation; Nucleic Acid Regulatory Sequences; Organ; Pathogenicity; Pathway interactions; Patients; Pharmaceutical Preparations; Plasma Cells; Play; Process; Production; Refractory; Research; Rheumatoid Arthritis; Role; Severity of illness; Signal Pathway; Signal Transduction; Squalene; Study models; Systemic Lupus Erythematosus; Systemic Therapy; TLR7 gene; Testing; Therapeutic Intervention; Time; Tissues; Transcription Factor AP-1; Up-Regulation; Vaccine Antigen; Vaccines; base; cytokine; epigenome; experimental study; inhibitor/antagonist; interleukin-21; mouse model; novel therapeutics; pathogen; prevent; programs; response; support network; transcription factor; transcriptome

Autoimmune disease like Rheumatoid Arthritis (RA) or Systemic Lupus Erythematosus (SLE) cause significant suffering and represent a huge financial burden. Since many individuals are refractory to treatment with the available drugs, there is a large unmet need to develop new therapeutics for these patients. Although we know that B cells, antibody (Ab) secreting cells (ASCs), inflammatory cytokines and TLR ligands all play important roles in driving humoral immune responses to pathogens, vaccines and self-antigens, we still lack a fundamental understanding of how the signals provided by cytokines and TLR ligands are integrated by responding B cells to promote the development and expansion of ASCs, which in the case of autoimmunity may produce pathogenic autoAbs. We characterized an unusual subset of B cells (DN2 cells), which are found in healthy donors (HD) and expanded in some SLE and RA patients. We showed that DN2 cells, which correlate with disease severity in SLE, can rapidly differentiate into ASCs, suggesting that these cells are “poised” pre-ASCs. Our data suggest that early signals provided by IFNg control DN2 development in SLE patients and HD. Moreover, ex vivo experiments using SLE patient DN2 cells reveal that differentiation of these IFNg-“primed” pre-ASCs requires additional signals provided by TLR7 ligands and IL-21 and we observed that signals provided by IFNg and IFNa control TLR7-dependent but not TLR9-dependent differentiation of human B cells. We showed that IFNg but not IFNa induces expression of the transcription factor IRF1 in human B cells and that IRF1 promotes TLR7-driven human ASC formation. Therefore, we identified at least 2, and likely 3, independent B cell differentiation pathways that are differentially reliant on IFNs, IFN-induced transcription factors and TLR ligands. To date, no studies have focused on how IFNg regulates B cell differentiation and why B cell differentiation in response to TLR7 and TLR9 are differentially dependent on IFNg. In this proposal, we will test our central hypothesis that IFNg selectively induces IRF1-dependent reprogramming of B cells, thereby licensing these cells to differentiate in response to (auto)antigens that engage the TLR7 signaling network. The immediate objectives of this proposal are to (i) examine the overlapping and distinct roles that IFNg and IFNa play in promoting TLR7-dependent human ASC development; (ii) determine how IRF1 supports B cell differentiation and (iii) evaluate why TLR7- mediated B cell differentiation is reliant on IFN-derived signals. Our long-term goal is to use what we learn about the fundamental mechanisms controlling TLR and cytokine-induced B cell differentiation to identify interventions that can regulate the formation, maintenance or function of ASCs in health and disease. This research is significant because we will, for the first time, define the mechanistic basis for IFNg-dependent TLR7-driven human B cell differentiation. We believe that our studies are important as they will advance our fundamental understanding of the mechanisms controlling human B cell differentiation and may in the future allow selective targeting of TLR7-driven autoAb responses without affecting B cell responses to other types of antigens. !

自身免疫性疾病，例如类风湿关节炎（RA）或全身性红斑狼疮（SLE）引起明显的 痛苦并代表了一个巨大的金融伯恩。由于许多人对使用 可用的药物，为这些患者开发新疗法有很大的未满足。虽然我们知道 B细胞，抗体（AB）分泌细胞（ASC），炎症细胞因子和TLR配体都起着重要作用 在驱动病原体，疫苗和自我抗原的体液免疫调查中的作用，我们仍然缺乏基本 了解细胞因子和TLR配体提供的信号是如何通过响应B细胞整合的 促进ASC的发展和扩展，在自身免疫的情况下可能会产生致病性 自动。我们表征了在健康供体（HD）中发现的一个异常的B细胞（DN2细胞）的子集（DN2细胞） 并在一些SLE和RA患者中扩展。我们表明DN2细胞与疾病严重程度相关 在SLE中，可以迅速将其分化为ASC，表明这些细胞是“固执”的预审长。我们的数据暗示 IFNG控制DN2发育在SLE患者和HD中提供的早期信号。此外，Ex Vivo 使用SLE患者DN2细胞进行的实验表明，这些IFNG“ Primed”预审核的分化需要 TLR7配体和IL-21提供的其他信号，我们观察到IFNG和IFNA提供的信号 控制TLR7依赖性但不依赖于人类B细胞的TLR9依赖性分化。我们证明了IFNG，但没有 IFNA影响人B细胞中转录因子IRF1的表达，而IRF1促进了TLR7驱动 人类ASC形成。因此，我们至少确定了2个，可能3个独立的B细胞分化 在IFN，IFN诱导的转录因子和TLR配体上不同的途径。迄今为止，没有 研究的重点是IFNG如何调节B细胞分化以及为什么B细胞分化响应于 TLR7和TLR9取决于IFNG。在此提案中，我们将检验我们的中心假设 IFNG选择性诱导B细胞的IRF1依赖性重编程，从而许可这些细胞以区分 响应于参与TLR7信号网络的（自动）抗原。该提议的直接目标 （i）检查IFNG和IFNA在促进TLR7依赖性方面起着重叠和独特的作用 人类ASC的发展； （ii）确定IRF1如何支持B细胞分化，并评估为什么TLR7-- 介导的B细胞分化依赖于IFN衍生的信号。我们的长期目标是使用我们所学的知识 控制TLR和细胞因子诱导的B细胞分化的基本机制以识别干预措施 这可以调节ASC在健康和疾病中的形成，维护或功能。这项研究是 意义重大，因为我们将第一次定义IFNG依赖性TLR7驱动的机械基础 人B细胞分化。我们认为我们的研究很重要，因为它们将推动我们的基本 了解控制人B细胞分化的机制，并可能将来允许选择性 靶向TLR7驱动的自动启动反应，而不会影响B细胞对其他类型抗原的反应。 呢