Studies of Osteoclast Lineage in Health and Disease

健康和疾病中破骨细胞谱系的研究

• 批准号: 10005546
• 负责人: Joseph A Lorenzo
• 金额: $ 41.17万
• 依托单位: UNIVERSITY OF CONNECTICUT SCH OF MED/DNT
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-09-12 至 2021-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10005546
• 关键词: Age; Blood; Blood Circulation; Bone Diseases; Bone Marrow; Bone callus; CXCR4 gene; Calvaria; Cells; Development; Disease; Disease model; Drug Targeting; Engraftment; Femoral Fractures; Fracture; Gene Deletion; Goals; Health; Home environment; Homeostasis; Homing; Inflammation; Inflammatory; Kinetics; Label; Marrow; Measures; Modeling; Molecular; Monitor; Mus; Myelogenous; Osteitis; Osteoclasts; Osteolysis; Osteolytic; Parabiosis; Phenotype; Population; Process; Receptor Cell; Role; Signal Transduction; Site; Source; Spleen; TNF gene; Testing; Time; Vascular blood supply; bone; bone turnover; chemokine receptor; defined contribution; experimental study; in vivo; migration; progenitor; recruit; repaired; therapy design; therapy development; trafficking

Although, we know much about the molecular signals that regulate OC function, we know relatively little about the lineage development and mechanisms that OC use to develop from progenitors. The goal of this application is to better define OC progenitor (OCP) development and trafficking and the mechanisms regulating this process in health and disease so that we can identify potential drug targets to develop superior therapies for bone diseases. The central hypotheses are: 1) During homeostasis marrow-resident cells are the principal OCP source, while during inflammation or fracture repair, circulating cells become a significant source of OCP. 2) The mechanisms regulating OCP migration, engraftment and maturation to OC in bone differ between healthy and disease states. To test these hypotheses, we propose the following aims: 1. Define the role that CX3CR1+ OCP have in OC development during homeostasis and identify mechanisms regulating their homing and engraftment. 1A) Perform time course studies in CX3CR1-CreERT2-Ai14 mice at various ages to examine the kinetics of labeled OC. We will also monitor the kinetics of labeled OCP in the bone marrow, blood and spleen. 1B) The cell receptors EBI2 and CX3CR1 are expressed on OCP and have previously been implicated to influence OCP homing, engraftment and maturation. We will determine their role in OCP lineage development and trafficking in vivo under homeostatic conditions using CX3CR1-CreERT2-Ai14 mice and gene deletion. 2. Examine OCP homing from the circulation during bone inflammation and fracture repair. These studies will examine two disease models in which we previously demonstrated that circulating OCP are recruited to engraft in bone: TNFa-induced bone inflammation and a repairing fracture. 2A) Study a TNFa-induced inflammatory bone model (a WT parabiont has TNFα injected over its calvaria; the other parabiont is a CX3CR1-EGFP; TRAP-tdTomato mouse) and determine the rate that circulating labeled cells home to the inflammatory site, form OC and disappear. OCP kinetics will be measured as in 1A. 2B) Study a parabiosis fracture model (a WT parabiont receives a femur fracture; the other parabiont is a CX3CR1-EGFP; TRAP-tdTomato mouse) and determine the rate that circulating labeled cells home to the repairing callus, form OC and disappear. OCP kinetics will be measured as in 1A. 2C) Determine the phenotype and kinetics of circulating OCP that home to bone with TNFa-induced inflammation or fracture repair by injecting various populations of OCP from CX3CR1-EGFP; TRAP-tdTomato mice and monitoring the rates that labeled OC appear and disappear in bone. 2D) Determine if gene deletion of EBI2 or CX3CR1 CXCR4 alters the ability of circulating OCP to home and mature into OC in the models of TNFa-induced bone inflammation and fracture repair studied in aim 2C.

虽然我们对调节OC功能的分子信号了解很多，但对OC的分子信号却知之甚少。 OC用于从祖细胞发育的谱系发育和机制。这个应用程序的目标是 更好地定义原始组织的发展和贩运，以及管理这一过程的机制 这样我们就可以确定潜在的药物靶点来开发上级骨治疗方法 疾病主要假设是：1）在稳态过程中，骨髓细胞是主要的OCP 来源，而在炎症或骨折修复期间，循环细胞成为炎症的重要来源 OCP。2)OCP在骨中迁移、植入和成熟为OC的调节机制不同 健康和疾病之间的关系。为了验证这些假设，我们提出了以下目标： 1.定义CX 3CR 1 + OCP在体内平衡过程中OC发育中的作用， 调节其归巢和植入的机制。 1A）在不同年龄的CX 3CR 1-CreERT 2-Ai 14小鼠中进行时程研究，以检查CX 3CR 1-CreERT 2-Ai 14的动力学。 标记为OC。我们还将监测标记OCP在骨髓、血液和脾脏中的动力学。 1B）细胞受体EBI 2和CX 3CR 1在OCP上表达，并且先前已经暗示其与OCP相关。 影响OCP归巢、植入和成熟。我们将确定它们在OCP谱系发展中的作用 以及在稳态条件下使用CX 3CR 1-CreERT 2-Ai 14小鼠和基因缺失的体内运输。 2.检查骨炎症和骨折修复过程中OCP从循环中的归巢。 这些研究将检查两种疾病模型，在这两种模型中，我们先前证明了循环OCP是 招募来植入骨中：TNF α诱导的骨炎症和修复性骨折。 2A）研究TNF α诱导的炎性骨模型（WT副生物在其颅骨上注射TNFα; 另一种寄生虫是CX 3CR 1-EGFP; TRAP-tdTomato小鼠），并测定循环标记细胞 回到炎症部位形成OC然后消失OCP动力学将如1A中所述进行测量。 2B）研究联体共生骨折模型（WT联体生物接受股骨骨折;另一个联体生物是股骨骨折;另一个联体生物接受股骨骨折。 CX 3CR 1-EGFP; TRAP-tdTomato小鼠），并测定循环标记细胞归巢至靶细胞的速率。 修复骨痂，形成OC并消失。OCP动力学将如1A中所述进行测量。 2C）确定循环OCP的表型和动力学，其通过TNF α诱导的炎症返回骨 或通过注射来自CX 3CR 1-EGFP; TRAP-tdTomato小鼠的各种OCP群体进行骨折修复， 监测标记OC在骨中出现和消失的速率。 2D）确定EBI 2或CX 3CR 1 CXCR 4的基因缺失是否改变循环OCP归巢和转运的能力。 在目的2C中研究的TNF α诱导的骨炎症和骨折修复模型中成熟为OC。