Studies of Osteoclast Lineage in Health and Diseases

健康和疾病中破骨细胞谱系的研究

• 批准号: 10534681
• 负责人: Joseph A Lorenzo
• 金额: $ 43.59万
• 依托单位: UNIVERSITY OF CONNECTICUT SCH OF MED/DNT
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-06-23 至 2025-11-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10534681
• 关键词: Adoptive Transfer; Age; Blood; Bone Diseases; Bone Marrow; Bone Resorption; Bone callus; CX3CR1 gene; Calvaria; Cells; Circulation; Data; Development; Disease; Disease model; Drug Targeting; Engraftment; Femoral Fractures; Fracture; Gene Deletion; Goals; Health; Home; Homeostasis; Homing; Inflammation; Inflammatory; Kinetics; Label; Marrow; Modeling; Molecular; Monitor; Mus; Myelogenous; Osteitis; Osteoclasts; Osteolysis; Osteolytic; Parabiosis; Phenotype; Population; Process; Role; Signal Transduction; Site; Source; Spleen; TNF gene; Testing; Time; Vascular blood supply; bone; bone fracture repair; bone turnover; chemokine receptor; defined contribution; experimental study; in vivo; migration; osteoclast progenitor; 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 and mechanisms that OC use to develop from progenitors. The goal of this application is to better define OC progenitor (OCP) maturation 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, engraftment and maturation to OC: 1A) Perform time course studies in CX3CR1-CreERT2-Ai14 mice at various ages to examine labeled OC formation kinetics. We will also monitor the kinetics of labeled OCP in the bone marrow, blood and spleen. 1B) The chemokine receptor CX3CR1 is expressed on OCP and has previously been implicated to influence OCP homing, engraftment and maturation. We will determine its role in OCP lineage development and trafficking in vivo under homeostatic conditions (when marrow-derived cells predominate as the OCP source) using CX3CR1-CreERT2-Ai14 mice to generate Cx3cr1 gene deletions. 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. 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. 2C) Determine the phenotype and kinetics of circulating OCP that home, mature and engraft in bone with TNFa-induced inflammation or fracture repair by injecting selected populations of OCP from CX3CR1-EGFP; TRAP-tdTomato mice and monitoring the rates that labeled OC appear and disappear in bone. 2D) Determine the effect that deletion of Cx3cr1 has on the ability of circulating OCP to home, engraft and mature in bone with TNFa-induced inflammation or a fracture repair using parabiosis and adoptive transfer.

尽管我们对调节OC功能的分子信号了解很多，但我们对其知之甚少