Growth Factor Based on Enhancement of Bone Repair

基于增强骨修复的生长因子

• 批准号: 9440342
• 负责人: IVO Kalajzic
• 金额: $ 35.09万
• 依托单位: UNIVERSITY OF CONNECTICUT SCH OF MED/DNT
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-04-01 至 2022-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9440342
• 关键词: Adverse effects; BMP2 gene; Bone Regeneration; Cell Count; Cell Lineage; Chondrocytes; Clinical; Combined Modality Therapy; Complex; Data; Defect; Development; Dose; Evaluation; Fracture; Fracture Healing; Future; Gene Expression; Genetic; Growth Factor; Histologic; Human; In Vitro; Luciferases; Mechanics; Mediating; Mesenchymal Stem Cells; Mitogens; Modeling; Molecular; Orthopedics; Osteoblasts; Osteocytes; Osteogenesis; Outcome; Pathway interactions; Periodontium; Periosteal Cell; Phosphorylation; Phosphotransferases; Platelet-Derived Growth Factor; Platelet-Derived Growth Factor alpha Receptor; Prevalence; Process; Recombinants; Reporter; Role; Signal Pathway; Signal Transduction; Stem cells; Testing; Tissues; Transgenic Model; Transgenic Organisms; Treatment Protocols; base; blocking factor; bone; bone healing; cell growth; cell motility; cell type; clinical application; cost; cytokine; dentin matrix protein 1; design; dosage; effective therapy; healing; improved; in vivo; in vivo Model; in vivo evaluation; inhibitor/antagonist; long bone; microCT; mouse model; novel; osteogenic; platelet-derived growth factor BB; prevent; receptor; repaired; research clinical testing; targeted treatment

The healing of fractures and bone defects involves complex interactions between cells and growth factors. Currently, recombinant BMP2, a potent inducer of bone formation, is approved for use in a number of orthopedic applications, however it can generate serious side effects likely associated with the high doses used. Combining BMP2 with other modulators of bone formation could improve its efficacy and potency in orthopedic applications. Our preliminary data indicate that PDGF blocks the effects of BMP2 in periosteal progenitor cells and prevents BMP2 induced osteogenesis. PDGF and its receptors are abundant during fracture healing, however the in vivo role of PDGF during healing, and how it interacts with BMP2 signaling, is not well defined. Our hypothesis is that PDGF is a critical regulator of BMP2 signaling during bone healing. We propose three aims: In aim 1 we will define the mechanisms by which PDGF regulates BMP2 signaling. The effects of PDGF on BMP2-induced Smad signaling will be evaluated at the level of Smad phosphorylation, luciferase reporter activity and downstream gene expression in periosteal progenitor cells in vitro. We will evaluate which downstream signaling pathways are involved in the inhibition of BMP signaling by PDGF. In vivo studies will be conducted in Aim 2 and Aim 3. We will utilize models of bone fracture and bone defects. In Aim 2 we will evaluate the effects of disrupting endogenous PDGFRβ signaling using an in vivo conditional deletion approach. We propose to target deletion to mesenchymal progenitor cells, chondrocytes and osteoblast lineages during fracture healing using lineage specific inducible Cre transgenic models. Effects of conditional activation of PDGFRβ signaling on fracture healing will be achieved by tissue specific expression of a constitutively active form of the PDGFRβ kinase domain. In Aim 3 we will evaluate the efficacy of BMP2/PDGF combination treatment delivered locally. In addition, we will evaluate the effects of a PDGFR inhibitor delivered systemically at different stages of healing allowing for precise control of dosage and timing. Combination treatments will be tested with a dose of BMP2 that alone does not induce bridging of the defect. Our project will provide better understanding on the interactions of the PDGF and BMP2 during osteogenesis and bone healing. The potential for an increase in osteogenic repair by modulating PDGF and BMP2 signaling during bone defect healing in vivo will outline the possibility of future clinical evaluation of this treatment.

裂缝和骨缺损的愈合涉及细胞与生长因子之间的复杂相互作用。 当前，重组BMP2是骨形成的潜在诱导剂，被批准用于多个 但是，骨科应用可能会产生与高剂量有关的严重副作用 用过的。将BMP2与骨形成的其他调节剂相结合可以提高其效率和效力 骨科应用。我们的初步数据表明PDGF阻止了BMP2在骨膜中的影响 祖细胞并防止BMP2诱导成骨。 PDGF及其接收器在 骨折愈合，但是PDGF在愈合过程中的体内作用及其与BMP2信号的相互作用是 定义不当。 我们的假设是，PDGF是骨愈合过程中BMP2信号传导的关键调节剂。我们提出了三个 目的：在AIM 1中，我们将定义PDGF调节BMP2信号传导的机制。 PDGF的影响 在BMP2诱导的SMAD信号上将在SMAD磷酸化水平上评估荧光素酶报告基因 体外骨膜祖细胞中的活性和下游基因表达。我们将评估哪个 下游信号通路参与PDGF对BMP信号的抑制。体内研究将是 在AIM 2和AIM 3中进行。我们将利用骨断裂和骨缺损模型。在目标2中，我们将 评估使用体内条件缺失破坏内源性PDGFRβ信号传导的影响 方法。我们建议将缺失靶向间充质祖细胞，软骨细胞和成骨细胞 使用谱系特定诱导的CRE转基因模型在断裂愈合过程中谱系。条件的影响 PDGFRβ信号在断裂愈合上的激活将通过组织特异性表达来实现 PDGFRβ激酶结构域的组成性活性形式。在AIM 3中，我们将评估BMP2/PDGF的效率 联合处理在本地提供。此外，我们将评估pDGFR抑制剂的影响 在康复的不同阶段系统地，可以精确控制剂量和时机。组合 治疗将通过一定剂量的BMP2进行测试，仅凭BMP2不会引起缺陷的桥接。 我们的项目将在成骨过程中更好地了解PDGF和BMP2的相互作用 和骨骼康复。通过调节PDGF和BMP2信号传导增加成骨修复的潜力 在骨缺损期间，体内将概述对这种治疗的未来临床评估的可能性。