Conditional Deletion of Irf8 in Monocyte Macrophage Lineage Provides Novel Insight into Irf8s Important Function in Osteoclast Regulation and Bone Metabolism

单核巨噬细胞谱系中 Irf8 的条件性缺失为 Irf8 在破骨细胞调节和骨代谢中的重要功能提供了新的见解

• 批准号: 10213697
• 负责人: Vivek Thumbigere-Math
• 金额: $ 15.45万
• 依托单位: UNIVERSITY OF MARYLAND BALTIMORE
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-07-09 至 2023-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10213697
• 关键词: ATAC-seq; Address; Adult; Affect; American; Animals; Automobile Driving; Biological; Biological Assay; Biological Process; Bone Diseases; Bone Resorption; Cell Culture System; Cells; Cervical; ChIP-seq; Community Health Services; Complex; Data; Development; Disease; Economic Burden; Exhibits; Flow Cytometry; Fostering; Foundations; Future; Genes; Genetic Transcription; Goals; Health; Hematopoietic stem cells; Histology; Homeostasis; Human; IFN consensus sequence binding protein; Immunohistochemistry; In Vitro; Individual; Inflammatory; Intervention; Knockout Mice; Knowledge; Mediating; Mission; Molecular; Mus; Mutation; Myeloid Cells; Osteoclasts; Osteoporosis; Pathogenicity; Pathologic; Periodontal Diseases; Periodontitis; Physiological; Play; Population; Predisposition; Process; Property; Public Health; Receptor Gene; Regulation; Research; Research Personnel; Resources; Rheumatoid Arthritis; Risk; Role; Root Resorption; Shapes; Signal Transduction; Sorting - Cell Movement; Techniques; Testing; Therapeutic; Tissues; United States National Institutes of Health; Work; aged; base; bone metabolism; conditional knockout; effective intervention; epigenetic profiling; genetic approach; improved; innovation; insight; macrophage; microCT; monocyte; mouse model; next generation sequencing; novel; osteoclastogenesis; psychologic; public health relevance; risk variant; single-cell RNA sequencing; social; targeted treatment; transcription factor; transcriptomics; treatment strategy

PROJECT SUMMARY/ABSTRACT Diseases such as periodontitis, osteoporosis, and rheumatoid arthritis, are characterized by excessive bone resorption due to increased osteoclast activity. It is estimated that osteoporosis affects ~10 million Americans with another 19 million at risk. Periodontitis affects ~46% of the U.S. adults aged ³30 years. Rheumatoid arthritis affects ~54.4 million U.S. adults - equating to about 25% of the population. The impact of these diseases in terms of social, psychological, and economic burden on individuals, communities, and health services is enormous. Despite these concerns, the molecular mechanisms contributing to dysregulated osteoclast function in these pathological conditions remain unclear, creating a critical knowledge gap in developing targeted interventions and therapeutic strategies. Our long-term goal is to identify and gain an in-depth understanding of the positive and negative regulators of osteoclast differentiation and utilize the gained knowledge to develop new interventional and therapeutic approaches for osteoclast-mediated disorders. Towards achieving our long-term goal, we have identified a novel mutation in the Interferon Regulatory Factor 8 (IRF8) gene that promotes increased osteoclast activity and susceptibility to a rare periodontal disease termed “Multiple Idiopathic Cervical Root Resorption (MICRR). The current proposal takes a new direction to gain in-depth knowledge about IRF8 role in osteoclast regulation and periodontal homeostasis. To date, IRF8’s role in osteoclastogenesis has been studied using Irf8 gKO mice. However, the severely altered population and properties of hematopoietic stem cells in Irf8 gKO mice has affected the detailed analysis of IRF8 function in osteoclast precursors derived from a monocyte/macrophage lineage. To overcome this limitation, we have generated a myeloid cell-specific Irf8 conditional knockout (cKO). In this application, we will apply genetic approaches and use both in vitro cell culture systems and Irf8 cKO mouse model to investigate: 1) Importance of IRF8 in monocyte subset development (2) Osteoclastogenic potential of different monocyte subsets and how it is influenced by IRF8, and (3) Specific monocyte subsets contributing to tissue destruction in periodontitis. We will pursue these aims using an innovative combination of Irf8 cKO mouse model and techniques such next-generation sequencing, flow cytometry, and micro-CT. The proposed research is significant, because it will provide critical mechanistic insights into the regulation of complex networks of transcription factors that govern osteoclast differentiation. This work will develop foundational resources that will be used by other researchers for studying various bone disorders and inflammatory disorders that have known risk alleles in IRF8. Most importantly, the results will lay the groundwork to develop better treatment options for various osteoclast-mediated bone disorders, including periodontal disease.

项目概要/摘要 牙周炎、骨质疏松症和类风湿性关节炎等疾病的特点是骨量过多 由于破骨细胞活性增加而发生吸收。据估计，骨质疏松症影响约 1000 万美国人 另有 1900 万人面临风险。约 46% 的 30 岁美国成年人患有牙周炎。类风湿关节炎 影响约 5440 万美国成年人，约占总人口的 25%。这些疾病的影响 对个人、社区和卫生服务造成的社会、心理和经济负担是巨大的。 尽管存在这些担忧，导致这些疾病中破骨细胞功能失调的分子机制 病理状况仍不清楚，在制定有针对性的干预措施方面造成了关键的知识差距 和治疗策略。我们的长期目标是识别并深入了解积极的一面 和破骨细胞分化的负调节剂，并利用所获得的知识开发新的 破骨细胞介导的疾病的介入和治疗方法。为了实现我们的长期目标 为了实现这一目标，我们在干扰素调节因子 8 (IRF8) 基因中发现了一种新的突变，该突变可促进 破骨细胞活性增加，对一种罕见的牙周病（称为“多发性特发性颈椎病”）的易感性增加 根吸收（MICRR）。当前的提案采取了新的方向来深入了解 IRF8 在破骨细胞调节和牙周稳态中的作用。迄今为止，IRF8在破骨细胞生成中的作用已被证实 使用 Irf8 gKO 小鼠进行研究。然而，造血干细胞的数量和特性发生了严重改变 Irf8 gKO 小鼠中的细胞影响了破骨细胞前体中 IRF8 功能的详细分析 单核细胞/巨噬细胞谱系。为了克服这一限制，我们生成了骨髓细胞特异性 Irf8 条件性敲除（cKO）。在此应用中，我们将应用遗传方法并使用体外细胞培养 系统和 Irf8 cKO 小鼠模型来研究：1) IRF8 在单核细胞亚群发育中的重要性 (2) 不同单核细胞亚群的破骨潜能及其受 IRF8 的影响，以及 (3) 特异性 单核细胞亚群有助于牙周炎中的组织破坏。我们将通过以下方式实现这些目标： Irf8 cKO小鼠模型与新一代测序、流式细胞术等技术的创新组合 细胞计数和显微 CT。拟议的研究意义重大，因为它将提供关键的机制 深入了解控制破骨细胞分化的复杂转录因子网络的调节。 这项工作将开发基础资源，其他研究人员将使用这些资源来研究各种骨骼 IRF8 中具有已知风险等位基因的疾病和炎症性疾病。最重要的是，结果将揭晓 为各种破骨细胞介导的骨疾病开发更好的治疗方案奠定了基础，包括 牙周病。

项目成果

Monocyte Subsets With High Osteoclastogenic Potential and Their Epigenetic Regulation Orchestrated by IRF8.

• DOI: 10.1002/jbmr.4165
• 发表时间: 2021-01
• 期刊: Journal of bone and mineral research : the official journal of the American Society for Bone and Mineral Research
• 作者: Das A;Wang X;Kang J;Coulter A;Shetty AC;Bachu M;Brooks SR;Dell'Orso S;Foster BL;Fan X;Ozato K;Somerman MJ;Thumbigere-Math V
• 通讯作者: Thumbigere-Math V