G-protein coupled receptor EBI2 regulation of bone mass

G蛋白偶联受体EBI2对骨量的调节

• 批准号: 8596248
• 负责人: ERIN NEVIUS
• 金额: $ 5.22万
• 依托单位: YALE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-08-01 至 2015-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8596248
• 关键词: 3-Dimensional; Address; Adoptive Transfer; Antibody Formation; B-Lymphocytes; Biology; Bone Density; Bone Diseases; Bone Marrow; Bone Resorption; Bone Surface; CSF1R gene; Cell Communication; Cell fusion; Cells; Enzymes; Event; Exhibits; Exons; G-Protein-Coupled Receptors; Genetic; Grant; Health Care Costs; Histology; Human; Immigration; In Vitro; Ligands; Lymphoid; Macrophage Colony-Stimulating Factor; Microscopy; Molecular; Mus; Organ; Osteoblasts; Osteoclasts; Osteocytes; Osteoporosis; Ovariectomy; Pertussis Toxin; Photons; Play; Positioning Attribute; Probability; Process; Proteins; Regulation; Reporter; Role; Signal Transduction; Site; TNFSF11 gene; Techniques; Therapeutic Intervention; Time; Tissues; United States; aged; bone; bone mass; cell motility; cellular imaging; cellular transduction; cytokine; in vivo; intravital microscopy; long bone; migration; monocyte; novel; novel therapeutic intervention; osteoclastogenesis; overexpression; precursor cell; public health relevance; receptor coupling; research study; skeletal disorder; substantia spongiosa; two-photon

DESCRIPTION (provided by applicant): Osteoclasts differentiate from recirculating monocytes in niches adjacent to bone and require two critical signals, M-CSF and RANKL. How monocytes and osteoclast precursors migrate to the bone to interact with cells expressing the appropriate signals is unknown. Upon receiving these signals, osteoclast precursors undergo a differentiation process that requires cell-cell interaction and multiple cell fusion events. As cel-cell interaction and fusion is a dynamic process it predicts that osteoclast precursors continue to be motile after receiving differentiation signals. However, the mechanism(s) regulating monocyte/osteoclast precursor motility and migration to bone surfaces remain unresolved. Cell motility is largely controlled by G¿i-protein coupled receptors (G¿iPCR). We have recently uncovered that osteoclast precursors and osteoclasts robustly express EBI2 (Gpr183, a G¿iPCR) and EBI2 ligand is produced by cells located within osteoclastogenic bone marrow niches. Interestingly, osteoclasts derived from EBI2 -deficient mice in vitro are defective in size and EBI2 deficiency results in increased bone density and protects mice from ovariectomy- induced osteoporosis. Previous studies demonstrated that EBI2 and its ligands direct B cell migration to outer and interfollicular niches in secondary lymphoid organs during primary T-dependent antibody response. Therefore, we considered the possibility that EBI2 promotes BMDM and osteoclast precursor motility thereby increasing the probability of cell-cell interaction and cell-cell fusion essential for differentiation of large multinucleated osteoclasts. In preliminry experiments we found that EBI2-deficient cells moved with slower velocity and exhibited reduced displacement over time in vitro. Finally, our preliminary studies show that osteoblasts secrete substantial amounts of EBI2-ligand, which may promote directional migration of EBI2-expressing osteoclast precursors to bone niches. Indeed, retroviral overexpression of EBI2 in osteoclast precursors preferentially positions these cells in closer proximity to the bone surface than in control cells. A major focus of this proposal is to uncover the molecular mechanisms underlying EBI2 regulation of monocyte/osteoclast precursor motility and migration to sites of osteoclastogenesis. We will use a combination of 2-photon and cellular imaging approaches to characterize the role played specifically by EBI2 (Gpr183, a G¿iPCR) in osteoclast differentiation, motility, and migration to the bone surface. Given that GPCRs are prime targets for therapeutic interventions, the proposed studies have the potential to elucidate new aspects of osteoclast biology that should have a translational impact in bone disease.

描述（由申请方提供）：破骨细胞从骨附近壁龛中的再循环单核细胞分化，需要两个关键信号，M-CSF和RANKL。单核细胞和破骨细胞前体如何迁移到骨中与表达适当信号的细胞相互作用尚不清楚。在接收到这些信号后，破骨细胞前体经历需要细胞-细胞相互作用和多细胞融合事件的分化过程。由于细胞-细胞相互作用和融合是一个动态过程，它预测破骨细胞前体继续 在接收到分化信号后是能动的。然而，调节单核细胞/破骨细胞前体运动和迁移到骨表面的机制仍然没有得到解决。细胞运动主要由G蛋白偶联受体（G iPCR）控制。我们最近发现破骨细胞前体和破骨细胞强烈表达EBI 2（Gpr 183，一种G？iPCR），EBI 2配体由位于破骨细胞生成骨髓龛内的细胞产生。有趣的是，来自EBI 2缺陷小鼠的破骨细胞在体外的大小是有缺陷的， EBI 2缺乏导致骨密度增加，并保护小鼠免受卵巢切除术诱导的骨质疏松症。先前的研究表明，EBI 2及其配体指导B细胞迁移到初级T依赖性抗体应答期间次级淋巴器官的外部和滤泡间龛。因此，我们认为EBI 2促进BMDM和破骨细胞前体运动的可能性，从而增加了细胞间相互作用和细胞间融合的可能性，这对大型多核破骨细胞的分化至关重要。在体外实验中，我们发现EBI 2缺陷细胞以较慢的速度移动，并随着时间的推移表现出减少的位移。最后，我们的初步研究表明，成骨细胞分泌大量的EBI 2配体，这可能会促进定向迁移的EBI 2表达破骨细胞前体骨龛。事实上，破骨细胞前体中EBI 2的逆转录病毒过表达优先将这些细胞定位在比对照细胞更接近骨表面的位置。该建议的一个主要重点是揭示EBI 2调节单核细胞/破骨细胞前体运动和迁移到破骨细胞生成位点的分子机制。我们将使用双光子和细胞成像方法的组合来表征EBI 2（Gpr 183，一种G？iPCR）在破骨细胞分化、运动和迁移到骨表面中所起的作用。鉴于GPCR是治疗干预的主要靶点，拟议的研究有可能阐明破骨细胞生物学的新方面，这些生物学方面应该对骨疾病产生转化影响。