Rspondin-Lgr Axis in Bone Regeneration

骨再生中的 Rspondin-Lgr 轴

基本信息

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
项目类别：
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

项目摘要

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.

临床迫切需要开发新的疗法来促进骨再生。骨愈合过程的关键部分始于骨膜祖细胞的扩张损伤后立即发生，然后这些祖细胞分化为骨形成成骨细胞和软骨细胞，以及控制骨骼祖细胞/干细胞的机制我们的项目对针对损伤的激活、扩展和分化的描述很少。将研究 R-spondin（配体）-Lgr（受体）信号轴在调节这些信号中的作用祖细胞和骨再生 R-spondins（屋顶板特异性 spondin）是一个由四个成员组成的家族。分泌的基质细胞蛋白 (Rspo1-4)，与富含亮氨酸重复序列的 G 蛋白结合偶联受体 4/5/6 (Lgrs) 通过 Rspo-Lgr 相互作用增强经典 Wnt 通路。阻止 Wnt 卷曲受体的更新，从而确定典型的 Wnt 众所周知，经典 Wnt 信号传导水平在骨骼中发挥着重要作用。再生方面，很少有研究探索 Wnt 信号传导的正调节剂。特别是，骨折愈合中 Rspo-Lgr 的要求从未得到满足由于缺乏适当的模型而进行了检查，我们的主要目标是定义以下要求：我们已经定义了间充质祖细胞中对骨损伤的反应的 Rspo2/3 和 Lgr6。实现这一目标的三个具体目标在 Aim1 中，我们将使用单一和复合 Rspo2 和。 Rspo3 floxed 小鼠与 alphaSMACreERT2 小鼠杂交以破坏 Rspo2/3 基因将使用 microCT 评估骨折时的间充质祖细胞。典型 Wnt 信号传导的组织学、分子分析和机械测试。在目标 2 中，将评估 Rspo2/3 缺陷祖细胞的成骨潜力。将使用类似于以下参数的参数来研究基因敲除小鼠的骨愈合特性：目标1.目标3中，Rspo2将被递送到骨损伤部位以及对BMP和Wnt的影响信号传导、祖细胞激活和分化以及骨愈合的完成情况进行评估。该项目将确定骨折愈合中 Rspo2/3-Lgr6 相互作用的要求，并将为增强骨愈合提供新的治疗方向。