Rspondin-Lgr Axis in Bone Regeneration

骨再生中的 Rspondin-Lgr 轴

• 批准号: 10261766
• 负责人: Kurt David Hankenson
• 金额: $ 40.01万
• 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: 2020-09-18 至 2022-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10261766
• 关键词: Address; Adult; Attenuated; Binding; Bone Injury; Bone Regeneration; Bone callus; Calvaria; Cell Compartmentation; Cell Lineage; Cells; Chondrocytes; Clinical; Data; Development; Embryo; Family; Family member; Femoral Fractures; Fracture; Fracture Healing; Funding; GPR4 gene; Genes; Goals; Grant; Hand; Histology; In Vitro; Incidence; Injury; Knockout Mice; Lead; Leucine-Rich Repeat; Ligands; Limb Development; Limb structure; LoxP-flanked allele; Marrow; Mechanics; Mesenchymal; Mesenchymal Stem Cells; Mesenchyme; Minerals; Modeling; Molecular; Mus; Natural regeneration; Osteoblasts; Osteogenesis; Pathway interactions; Periosteal Cell; Periosteum; Play; Positioning Attribute; Process; Property; Proteins; Public Health; Publishing; Receptor Signaling; Regulation; Research; Role; Signal Transduction; Skeletal bone; Source; Testing; Therapeutic Uses; Time; WNT Signaling Pathway; base; bone; bone healing; cranium; experimental study; healing; in vivo; injured; insight; long bone; mRNA Expression; mouse model; novel; novel strategies; osteoblast differentiation; osteochondral tissue; osteogenic; osteoprogenitor cell; parent grant; prevent; progenitor; receptor; regenerative therapy; repaired; response; response to injury; skeletal; stem cell proliferation; stem cells; tissue regeneration

Our funded grant, R01DE030716, ”Rspondin-Lgr Axis in Bone Regeneration”, is focused on examining the role of Rspo2-Lgr6 signaling in calvarial regeneration. While there are some similarities in healing processes that exist between long bones and bones of the skull, there are also important differences. As an example, the calvaria heals exclusively through an intramembranous process while long bones heal through both intramembranous and endochondral bone formation. An additional important difference that exists between calvarial and long bone healing is the source and type of progenitor cell that contributes to bone healing. In long bones, a critical aspect of the bone healing process begins with the expansion of mesenchymal progenitors from the marrow and periosteum, which occurs immediately after injury. These cells then become bone forming osteoblasts and chondrocytes. However, mechanisms that control long-bone skeletal progenitor/stem cell activation, expansion, and differentiation in response to injury are poorly described. This supplement will study the role of the R-spondin (ligand) – Lgr (receptor) signaling axis in regulating long bone 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 long-bone fracture healing has never been examined, due to the lack of appropriate models. Our primary goal is to define the requirement of Rspo2/3 and Lgr6 in mesenchymal progenitors in response to femoral fracture. We have defined two 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 long-bone mesenchymal progenitors at the time of fracture. We will assess in vivo proliferation, Wnt signaling, and osteogenesis of progenitors, and analyze healing by using µCT, histology, and mechanical testing. In Aim 2, Lgr6 knockout mice will be investigated for their bone healing properties using parameters similarly to Aim 1. Completion of this project will identify the requirement of Rspo2/3-Lgr6 interaction in long-bone fracture healing and will provide new mechanistic insights into the action of cWnt signaling in bone healing that can be directly compared to similar experiments conducted with calvarial healing in the parent grant.

我们资助的赠款R01DE030716，“骨再生中的Rspondin-Lgr轴”，重点是检查角色 RSPO2-LGR6信号传导在钙​​调查中。虽然康复过程中有一些相似之处 存在于长骨头和头骨的骨头之间，也存在重要差异。例如， 瓦尔瓦里亚完全通过膜内过程愈合 膜内和软骨内骨形成。之间存在的另一个重要区别 颅骨和长骨愈合是有助于骨骼愈合的祖细胞的来源和类型。在 长骨头，骨骼愈合过程的关键方面始于间充质的膨胀 受伤后立即发生的骨髓和骨膜的祖细胞。然后这些细胞成为 骨形成骨细胞和软骨细胞。但是，控制长骨骨骼的机制 祖/干细胞激活，膨胀和响应损伤的分化的描述很差。这 补充剂将研究R-Spondin（配体） - LGR（受体）信号轴在调节长骨中的作用 祖和骨再生。 R-Spondins（特定于车顶板的赞助商）是一个四人一的家族 与富含亮氨酸重复的G蛋白偶联受体结合的基质蛋白（RSPO1-4）4/5/6 （lgrs）。 RSPO-LGR相互作用潜在的规范WNT途径通过防止Wnt毛躁的营业额 受体，因此决定了规范的Wnt信号传导水平。众所周知，众所周知 在骨骼再生中起重要作用，很少的研究探索了Wnt的正调节剂 信号。特别是，在长骨骨折愈合的背景下，RSPO-LGR的需求从来没有 由于缺乏适当的模型，我们对我们进行了检查。我们的主要目标是定义 间充质祖细胞中的RSPO2/3和LGR6响应股骨骨折。我们定义了两个特定的 旨在解决这个目标。在AIM1中，我们将使用单个和复合RSPO2和RSPO3 Floxed小鼠交叉 用AlphasmAcreert2小鼠在长骨间充质祖细胞中破坏RSPO2/3的基因 断裂时间。我们将评估祖细胞的体内增殖，Wnt信号传导和成骨，以及 通过使用µCT，组织学和机械测试来分析愈合。在AIM 2中，LGR6淘汰小鼠将是 使用参数与目标1相似的参数研究了其骨骼愈合的特性。该项目的完成将 确定在长骨断裂愈合中RSPO2/3-LGR6相互作用的需求，并将提供新的 对CWNT信号在骨愈合中的作用的机理洞察力可以直接与类似 在父母赠款中进行了钙治疗进行的实验。