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: 10055826
• 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 2022-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10055826
• 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.

项目摘要/摘要 牙周炎、骨质疏松症和类风湿性关节炎等疾病的特征是骨骼过多。 由于破骨细胞活动增加而导致的吸收。据估计，大约有1000万美国人患有骨质疏松症 另有1900万人处于危险之中。牙周炎影响了大约46%的30岁美国成年人。类风湿关节炎 影响约5440万美国成年人-相当于约25%的人口。这些疾病在以下方面的影响 对个人、社区和卫生服务造成巨大的社会、心理和经济负担。 尽管有这些担忧，导致这些患者破骨细胞功能失调的分子机制 病理情况仍不清楚，在开发有针对性的干预措施方面存在严重的知识差距 和治疗策略。我们的长期目标是找出并深入了解积极的 和破骨细胞分化的负调控因子，并利用所获得的知识开发新的 破骨细胞介导性疾病的介入和治疗方法。朝着实现我们的长期目标 目的：我们在干扰素调节因子8(IRF8)基因中发现了一种新的突变，它能促进 破骨细胞活性增强与一种名为“多发性颈椎病”的罕见牙周病的易感性 牙根吸收(MICRR)。目前的建议采取了一个新的方向，以获得对IRF8的深入了解 破骨细胞调节和牙周动态平衡的作用。到目前为止，IRF8的S在破骨细胞形成中的作用一直是 以IRF8 GKO小鼠为研究对象。然而，造血干细胞的数量和性质发生了严重的变化 IRF8 GKO小鼠中的细胞影响了对破骨细胞前体细胞中IRF8功能的详细分析 单核/巨噬细胞谱系。为了克服这一限制，我们产生了一个髓系细胞特异性的IRF8 条件淘汰赛(CKO)在这项应用中，我们将应用遗传方法和使用体外细胞培养 系统和IRF8 CKO小鼠模型研究：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细胞分化潜能及其受IRF8的影响，以及(3)特异性 单核细胞亚群参与牙周炎的组织破坏。我们将通过一个 IRF8 CKO小鼠模型与下一代测序、Flow等技术的创新结合 细胞学和显微CT。这项拟议的研究意义重大，因为它将提供关键的机制 对调控破骨细胞分化的复杂转录因子网络的洞察。 这项工作将开发基础资源，供其他研究人员用于研究各种骨骼 在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，结果将是 为各种破骨细胞介导的骨病开发更好的治疗方案的基础工作包括 牙周病。