Identification of an FGF-regulated signaling center in the Groove of Ranvier that controls longitudinal bone growth.

朗飞沟 (Groove of Ranvier) 中控制纵向骨生长的 FGF 调节信号中心的鉴定。

• 批准号: 10667798
• 负责人: David M Ornitz
• 金额: $ 20.55万
• 依托单位: WASHINGTON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-06-01 至 2025-05-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10667798
• 关键词: Affect; Alleles; Anatomy; Applications Grants; Bone Growth; Cell Lineage; Cell Separation; Cell physiology; Cell surface; Cells; Characteristics; Child; Childhood; Chondrocytes; Chondrogenesis; Clinical; Data; Development; Distal; Doxycycline; Dwarfism; Embryo; Embryonic Development; Engineering; Epiphysial cartilage; FGF9 gene; FGFR1 gene; FGFR3 gene; Feedback; Femur; Fibroblast Growth Factor; Fibroblast Growth Factor Receptors; Foundations; Fracture; Future; Genetic; Growth; Growth Factor; Health; Histologic; Impairment; In Situ Hybridization; Knowledge; Label; Ligands; Link; Location; Mus; Osteoblasts; Osteogenesis; Pathogenesis; Phenotype; Physiological; Population; Pregnancy; Proliferating; Property; Receptor Signaling; Regulation; Signal Transduction; Site; Skeletal Development; Sorting; Stromal Cells; Structure; Therapeutic; Tissues; Tomatoes; Transgenes; Vascular blood supply; biomarker identification; bone; capsule; embryo cell; genetic signature; insight; interest; postnatal; preservation; prevent; single cell mRNA sequencing; skeletal stem cell; tool; Affect; Alleles; Anatomy; Applications Grants; Bone Growth; Cell Lineage; Cell Separation; Cell physiology; Cell surface; Cells; Characteristics; Child; Childhood; Chondrocytes; Chondrogenesis; Clinical; Data; Development; Distal; Doxycycline; Dwarfism; Embryo; Embryonic Development; Engineering; Epiphysial cartilage; FGF9 gene; FGFR1 gene; FGFR3 gene; Feedback; Femur; Fibroblast Growth Factor; Fibroblast Growth Factor Receptors; Foundations; Fracture; Future; Genetic; Growth; Growth Factor; Health; Histologic; Impairment; In Situ Hybridization; Knowledge; Label; Ligands; Link; Location; Mus; Osteoblasts; Osteogenesis; Pathogenesis; Phenotype; Physiological; Population; Pregnancy; Proliferating; Property; Receptor Signaling; Regulation; Signal Transduction; Site; Skeletal Development; Sorting; Stromal Cells; Structure; Therapeutic; Tissues; Tomatoes; Transgenes; Vascular blood supply; biomarker identification; bone; capsule; embryo cell; genetic signature; insight; interest; postnatal; preservation; prevent; single cell mRNA sequencing; skeletal stem cell; tool

ABSTRACT Growing bones contain a circumferential anatomical structure called the groove of Ranvier (GOR) that may contain skeletal stem cells and signaling cells critical to skeletal development. Clinically, the GOR is important as pediatric fractures involving the GOR (Salter-Harris type II) often affect longitudinal bone growth. However, the identity and functional properties of cells within the GOR that regulate longitudinal bone growth are not known. Our preliminary data suggest that Fibroblast Growth Factor Receptors (FGFRs) within the GOR contribute to a “signaling center” that regulates adjacent growth plate chondrocytes and longitudinal bone growth. This observation establishes a functional link between cells in the GOR and the growth plate and has implications for the pathogenesis of pediatric physeal fractures. We refer to these poorly defined cells as the “GOR signaling center”. Conditional inactivation of Fgfr1 and Fgfr2 with the Osx-Cre transgene (Osx-Cre, DCKO mice) results in decreased longitudinal bone growth in postnatal mice. Through an unknown feedback mechanism, this inactivation also results in increased Fgf9 expression in the fibrous capsule and perichondrium, which is in close proximity to the GOR. Experimentally, we showed that expression of FGF9 in the perichondrium can activate FGFR3 in adjacent proliferating chondrocytes to suppress chondrogenesis. By regulating the expression of Osx-Cre, we show that Cre must be active during embryonic development to elicit this postnatal growth phenotype. Significantly, embryonic, but not postnatal, expression of Osx-Cre specifically targets the GOR. These data functionally define the region encompassing the GOR as the location of a critical FGFR1/2 signaling center by showing that inactivation of Fgfr1/2 in an embryonic cell lineage that gives rise to the GOR, rather than in definitive osteoblasts, is responsible for the dramatic reduction in bone growth observed in Osx-Cre, DCKO mice. In specific aim 1, we will use lineage tracing to differentially label the GOR and single cell mRNA sequencing to identify cell sub-populations within the GOR that have signaling center and/or skeletal stem cell properties. Identification of selective markers for these cell sub-populations will be used to reveal their location relative to the anatomical GOR. In specific aim 2, we will characterize the signaling properties of GOR cells for their ability to regulate osteogenesis and chondrogenesis. The studies proposed here will identify unique features of GOR cells as a potential cell signaling center with the unique ability to regulate adjacent growth plate tissue. These studies will provide mechanistic insight into why a large percentage of pediatric physeal fractures result in growth arrest despite theoretically preserving the proliferating chondrocytes and their intact blood supply. These studies will provide new genetic tools to study the GOR in future grant proposals and potential therapeutic insight that could be used to prevent growth arrest associated with physeal fractures.

抽象的 生长的骨头包含一个圆周的解剖结构，称为Ranvier（GOR）的凹槽 包含对骨骼发育至关重要的骨骼干细胞和信号细胞。临床上，GOR很重要 由于涉及GOR（Salter-Harris II型）的小儿骨折通常会影响纵向骨生长。然而， 调节纵向骨生长的GOR内细胞的身份和功能特性不是 已知。我们的初步数据表明，GOR中的成纤维细胞生长因子受体（FGFR） 有助于调节邻近生长板软骨细胞和纵向骨生长的“信号传导中心”。 该观察结果建立了GOR中细胞与生长板之间的功能联系，并具有含义 用于小儿骨折的发病机理。我们将这些定义不当的单元称为“ GOR信号传导 中心”。 与OSX-CRE转换（OSX-CRE，DCKO小鼠）的FGFR1和FGFR2的条件失活导致 产后小鼠的纵向骨生长减少。通过未知的反馈机制， 灭活还导致纤维囊和perichondrium中的FGF9表达增加，这是接近的 靠近Gor。在实验上，我们表明FGF9在perichondrium中的表达可以激活 邻近增殖软骨细胞中的FGFR3抑制软骨生成。 通过调节OSX-CRE的表达，我们表明CRE必须在胚胎发育过程中活跃 引起这种产后生长表型。值得注意的是，胚胎，但不是产后，OSX-CRE的表达 这些数据在功能上定义了包含GOR的区域 临界FGFR1/2信号传导中心的含量，表明在胚胎细胞谱系中FGFR1/2灭活 产生GOR，而不是确定的成骨细胞，是造成骨骼的急剧减少的原因 在OSX-CRE，DCKO小鼠中观察到的生长。 在特定的目标1中，我们将使用谱系跟踪来不同地标记GOR和单细胞mRNA测序 鉴定具有信号中心和/或骨骼干细胞特性的GOR内的细胞亚群。 这些细胞亚种群的选择性标记的识别将用于揭示其位置相对于 解剖学gor。在特定的目标2中，我们将表征GOR细胞的信号传导特性 调节成骨和软骨发生。这里提出的研究将确定GOR的独特特征 细胞作为具有独特调节相邻生长板组织的独特能力的潜在细胞信号转导中心。这些 研究将提供机械洞察，了解为什么很大一部分小儿物理学会导致生长 逮捕更喜欢理论上保存增殖的软骨细胞及其完整的血液供应。这些研究 将提供新的遗传工具来研究未来的赠款建议和潜在的治疗见解中的GOR 可以用来防止与物理骨折有关的生长停滞。