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: 10642784
• 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/10642784
• 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; Gene Expression Regulation; 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; 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 Induction; 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; cytokine; directed differentiation; epigenome; experimental study; inhibitor; 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. !

类风湿性关节炎 (RA) 或系统性红斑狼疮 (SLE) 等自身免疫性疾病会导致严重的 由于许多人难以接受这种治疗，因此造成巨大的经济负担。 尽管我们知道，但为这些患者开发新疗法的药物仍有大量未满足的需求。 B 细胞、抗体 (Ab) 分泌细胞 (ASC)、炎症细胞因子和 TLR 配体都发挥着重要作用 尽管我们仍然缺乏对病原体、疫苗和自身抗原的体液免疫反应的驱动作用 了解细胞因子和 TLR 配体提供的信号如何通过响应 B 细胞来整合 促进 ASC 的发育和扩张，在自身免疫的情况下可能产生致病性 我们对健康供体 (HD) 中发现的一个不寻常的 B 细胞亚群（DN2 细胞）进行了表征。 并在一些 SLE 和 RA 患者中进行了扩展，我们发现 DN2 细胞与疾病严重程度相关。 在 SLE 中，可以快速分化为 ASC，这表明这些细胞处于“准备就绪”的前 ASC 状态。 IFNg 提供的早期信号控制 SLE 患者和 HD 中的 DN2 发育。 使用 SLE 患者 DN2 细胞进行的实验表明，这些 IFNg“引发”的预 ASC 的分化需要 TLR7 配体和 IL-21 提供的附加信号，我们观察到 IFNg 和 IFNa 提供的信号 我们发现 IFNg 可以控制人类 B 细胞的 TLR7 依赖性分化，但不能控制 TLR9 依赖性分化。 IFNa 诱导人 B 细胞中转录因子 IRF1 的表达，并且 IRF1 促进 TLR7 驱动 因此，我们鉴定出至少 2 种（可能是 3 种）独立的 B 细胞分化。 迄今为止，尚无差异依赖 IFN、IFN 诱导的转录因子和 TLR 配体的途径。 研究重点是 IFNg 如何调节 B 细胞分化以及为什么 B 细胞分化会响应 TLR7 和 TLR9 对 IFNg 的依赖程度不同 在本提案中，我们将检验我们的中心假设： IFNg 选择性诱导 B 细胞依赖 IRF1 的重编程，从而允许这些细胞分化 响应参与 TLR7 信号网络的（自身）抗原 该提案的直接目标。 (i) 检查 IFNg 和 IFNa 在促进 TLR7 依赖性方面所发挥的重叠和不同作用 人类 ASC 发育；(ii) 确定 IRF1 如何支持 B 细胞分化以及 (iii) 评估为什么 TLR7- 介导的 B 细胞分化依赖于 IFN 衍生的信号。我们的长期目标是利用我们所学到的知识。 控制 TLR 和细胞因子诱导的 B 细胞分化的基本机制以确定干预措施 可以调节健康和疾病中 ASC 的形成、维持或功能。 意义重大，因为我们将首次定义 IFNg 依赖性 TLR7 驱动的机制基础 我们相信我们的研究很重要，因为它们将推进我们的基础研究。 了解控制人类 B 细胞分化的机制，并可能在未来允许选择性 靶向 TLR7 驱动的 autoAb 反应，而不影响 B 细胞对其他类型抗原的反应。 ！