Rspondin-Lgr Axis in Bone Regeneration

骨再生中的 Rspondin-Lgr 轴

• 批准号: 10469469
• 负责人: Kurt David Hankenson
• 金额: $ 37.94万
• 依托单位: UNIVERSITY OF CONNECTICUT SCH OF MED/DNT
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-09-10 至 2025-08-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10469469
• 关键词: Address; Adult; Attenuated; BMP2 gene; Binding; Bone Injury; Bone Regeneration; Bone callus; Calvaria; Cell Lineage; Cells; Chondrocytes; Clinical; Data; Defect; Development; Embryo; Family; Family member; Fracture; GPR4 gene; Genes; Goals; Hand; Histology; In Vitro; Incidence; Individual; Injury; Knockout Mice; Lead; Leucine-Rich Repeat; Ligands; Limb Development; Limb structure; LoxP-flanked allele; Mechanics; Mesenchymal; Mesenchymal Stem Cells; Mesenchyme; Minerals; Modeling; Molecular; Molecular Analysis; Mus; Osteoblasts; Osteogenesis; Pathway interactions; Periosteal Cell; Periosteum; Play; Positioning Attribute; Process; Property; Proteins; Public Health; Publishing; Receptor Signaling; Recombinants; Regulation; Reporter; Research; Role; Signal Transduction; Site; Skeletal Development; Testing; Therapeutic Uses; Time; WNT Signaling Pathway; base; bone; bone fracture repair; bone healing; bone repair; craniofacial; healing; in vivo; injured; long bone; mRNA Expression; microCT; mouse model; novel; novel strategies; novel therapeutics; osteoblast differentiation; osteochondral tissue; osteogenic; osteoprogenitor cell; prevent; progenitor; protein function; receptor; regenerative therapy; response; response to injury; skeletal; stem; stem cells; tissue regeneration

There is an urgent clinical need to develop new therapeutics to promote bone regeneration. A critical aspect of the bone healing process begins with the expansion of periosteal progenitors that occurs immediately after injury and then the differentiation of these progenitors to bone forming osteoblasts and chondrocytes, yet mechanisms that control skeletal progenitor/stem cell activation, expansion, and differentiation in response to injury are poorly described. Our project will study the role of the R-spondin (ligand) – Lgr (receptor) signaling axis in regulating these progenitors and bone regeneration. R-spondins (roof plate specific spondin) are a family of four secreted matricellular proteins (Rspo1-4) that bind to Leucine-rich repeat-containing G-protein coupled receptors 4/5/6 (Lgrs). Rspo-Lgr interaction potentiate canonical Wnt pathway by preventing the turnover of Wnt Frizzled receptors, and hence determines canonical Wnt signaling levels. While canonical Wnt signaling is known to play an important role in bone regeneration, very little research has explored positive modulators of Wnt signaling. In particular, the requirement of Rspo-Lgr in the context of fracture healing has never been examined due to lack of appropriate models. Our primary goal is to define the requirement of Rspo2/3 and Lgr6 in mesenchymal progenitors in response to bone injury. We have defined three specific aims to address this goal. In Aim1, we will use single and compound Rspo2 and Rspo3 floxed mice crossed with an alphaSMACreERT2 mouse to disrupt the Rspo2/3 genes in mesenchymal progenitors at the time of fracture. Bone healing will be assessed using microCT, histology, molecular analysis, and mechanical testing. Alterations in canonical Wnt signaling and osteogenic potential of Rspo2/3 deficient progenitors will be assessed. In Aim 2, Lgr6 knockout mice will be investigated for their bone healing properties using parameters similar to Aim 1. In Aim 3, Rspo2 will be delivered to bone injury sites and the impact on BMP and Wnt signaling, progenitor activation and differentiation, and bone healing assessed. Completion of this project will identify the requirement of Rspo2/3-Lgr6 interaction in fracture healing and will provide new therapeutic directions for enhancing bone healing.

紧急临床需要开发新的疗法以促进骨骼再生。一个 骨愈合过程的关键方面始于骨膜祖细胞的扩张 这是在受伤后立即发生的，然后将这些祖细胞分化为骨头 形成成骨细胞和软骨细胞，但控制骨骼祖细胞/干细胞的机制 响应损伤的激活，扩张和分化的描述很差。我们的项目 将研究R-Spondin（配体） - LGR（受体）信号轴的作用 祖和骨再生。 R-Spondins（车顶板特定的赞助商）是四口之家 与富含亮氨酸的重复G蛋白结合的分泌的母细胞蛋白（RSPO1-4） 耦合受体4/5/6（LGRS）。 RSPO-LGR相互作用潜在的规范WNT途径 防止Wnt卷曲受体的营业额，因此决定了规范的Wnt 信号水平。虽然已知典型的Wnt信号在骨骼中起重要作用 再生，很少的研究探索了WNT信号传导的正调节剂。在 特别是，RSPO-LGR在骨折愈合的背景下从未有过 由于缺乏适当的模型而被检查。我们的主要目标是定义 间充质祖细胞中的RSPO2/3和LGR6响应骨损伤。我们已经定义了 三个特定的目的是解决这一目标。在AIM1中，我们将使用单个和复合RSPO2和 Rspo3 floxed小鼠与αAmacreert2小鼠交叉，破坏RSPO2/3基因 骨折时的间充质祖细胞。将使用Microct评估骨骼愈合 组织学，分子分析和机械测试。规范Wnt信号的改变 RSPO2/3缺乏祖细胞的成骨潜力将被评估。在AIM 2中，lgr6 将使用类似于类似的参数研究敲除小鼠的骨骼愈合特性 AIM1。在AIM 3中，RSPO2将传递到骨损伤部位以及对BMP和WNT的影响 评估了信号传导，祖细胞激活和分化以及骨愈合。完成 该项目将确定骨折愈合中RSPO2/3-LGR6相互作用的需求，并将 提供新的治疗方向来增强骨骼愈合。