Development of Osteogenic Oxysterols for Local Bone Formation

用于局部骨形成的成骨氧甾醇的开发

基本信息

批准号：
8501384
负责人：
FARHAD PARHAMI
金额：
$ 32.92万
依托单位：
UNIVERSITY OF CALIFORNIA LOS ANGELES
依托单位国家：
美国
项目类别：
财政年份：
2011
资助国家：
美国
起止时间：
2011-07-11 至 2016-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8501384
关键词：
Address Adverse effects Animal Model Animals BMP2 gene Blood Circulation Bone Marrow Bone Matrix Bone Morphogenetic Proteins Bone Transplantation Calvaria Cholesterol Homeostasis Collagen Defect Development Effectiveness Embryo Erinaceidae Family Fibroblasts Fracture Future Gene Targeting Goals Healed Human In Vitro Investigation Ligands Liver Mediating Mediator of activation protein Mesenchymal Mesenchymal Stem Cells Modeling Molecular Molecular Mechanisms of Action Mus Neonatal Nuclear Organ Culture Techniques Osteogenesis Parents Pathway interactions Play Property Proteins Rat-1 Rattus Receptor Activation Receptor Signaling Recombinants Relative (related person)Reporting Role Signal Pathway Signal Transduction Speed Spinal Fusion Stromal Cells Structure-Activity Relationship Testing Tissues analog bone bone cell bone healing clinically relevant comparative efficacy cost healing immunogenic improved in vitro activity in vivo in vivo Model lipid biosynthesis notch protein novel osteogenic osteoprogenitor cell receptor response scaffold small molecule smoothened signaling pathway transcription factor

项目摘要

DESCRIPTION (provided by applicant): We have previously reported that specific endogenously produced small molecule oxysterols, formed in vivo as intermediaries of cholesterol metabolism, have potent osteogenic effects on multipotent mesenchymal stem cells (MSC) in vitro. We have shown that these effects are mediated through activation of the Hedgehog (Hh) signaling pathway, independent of Hh proteins. In addition, we have demonstrated that these oxysterols induce bone formation in neonatal mouse calvaria organ cultures, and bone healing in both a rat calvarial critical-sized defect model and a rat spinal fusion model in vivo. Thus, these oxysterols could potentially replace currently used expensive recombinant bone morphogenetic proteins (BMPs) and autogenous bone grafts for stimulation of local bone formation in non-healing fractures and critical bone defects. In addition, we have shown that when used in combination with BMPs, osteogenic oxysterols greatly reduce the concentration of BMPs required to induce effective osteogenesis in vitro. Accordingly, we have recently performed oxysterol structure activity relationship (SAR) studies that have resulted in the synthesis of a novel family of potent oxysterol analogues that possess osteogenic and anti-adipogenic activity equal or superior to the parent oxysterols. However, in addition to activating the Hh pathway, osteogenic oxysterols also activate liver X receptor (LXR) signaling whose role in osteogenesis is unclear and may promote oxysterol-induced osteogenesis by regulating targets of Notch signaling. Therefore, we hypothesize that osteogenic oxysterol analogues activate Hh and LXR signaling in osteoprogenitor cells and that both signaling pathways play an important role in osteogenic responses to oxysterols. To examine this hypothesis, we will pursue the following specific aims: 1) Elucidate the molecular signaling profile of osteogenic oxysterol analogues to determine the role and relative activation levels of Hh and LXR signaling in oxysterol-induced osteogenesis in vitro; 2) Examine the osteogenic activity of oxysterols and their mechanism of action in vivo for local administration using the rat spinal fusion and femoral defect models, while defining the optimal scaffold for local delivery and elucidating the role of Hh signaling in oxysterol effects in vivo; and 3) Examine the role of baseline and oxysterol-induced Hh pathway activity in BMP2-induced osteogenesis by determining whether Hh signaling through Gli transcription factors mediates the synergy between oxysterols and BMPs in stimulating osteogenesis in vitro and in vivo, and whether oxysterols may potentially improve the quality of the newly formed bone by inhibiting BMP2 stimulation of adipogenesis. These studies will provide important new information regarding the basic mechanisms regulating osteogenesis and the effects of oxysterols, as well as guidance for future investigations of oxysterols as a potential new class of osteoinductive agents for localized and perhaps systemic osteoregeneration.

描述（由申请人提供）：我们以前已经报道过，特定的内源性分子氧蛋白酶在体内形成，作为胆固醇代谢的中间体，对多能间充质干细胞（MSC）具有有效的成骨作用。我们已经表明，这些效应是通过刺猬（HH）信号通路（与HH蛋白无关的激活）介导的。此外，我们已经证明了这些氧蛋白酶在新生小鼠钙钙器官培养物中诱导骨骼形成，并在大鼠钙质症临界大小的缺陷模型和体内大鼠脊柱融合模型中诱导骨骼愈合。因此，这些氧蛋白酶可能有可能替代当前使用的昂贵的重组骨形态发生蛋白（BMP）和自动骨移植物，以刺激非治疗裂缝和临界骨缺损的局部骨形成。此外，我们已经表明，当与BMP结合使用时，成骨氧甲醇大大降低了在体外诱导有效的成骨所需的BMP浓度。因此，我们最近进行了氧蛋白酶结构活性关系（SAR）研究，这些研究导致了具有成骨和抗磷酸活性的新型有效的氧甲甲醇类似物的合成。但是，除了激活HH途径外，成骨氧甲醇还激活肝X受体（LXR）信号传导，其在成骨中的作用尚不清楚，并且可能通过调节NotCH信号的靶标而促进氧蛋白酶诱导的成骨。因此，我们假设成骨氧蛋白酶类似物激活了骨基源细胞中的HH和LXR信号传导，并且这两种信号通路在对氧蛋白酶的成骨反应中起重要作用。为了审查这一假设，我们将追求以下特定目的：1）阐明成骨氧蛋白酶类似物的分子信号传导谱，以确定HH和LXR信号在氧甲醇诱导的骨化中的作用和相对激活水平； 2）检查使用大鼠脊柱融合和股骨缺损模型的氧甲醇的成骨活性及其在局部给药中的作用机理，同时确定了局部递送的最佳支架，并阐明了HH信号在体内氧化酚效应中的作用； 3）检查基线和氧甲醇诱导的HH途径在BMP2诱导的骨生成中的作用，通过确定通过GLI转录因子确定HH信号是否介导了氧蛋白酶和BMP之间的Synergy在刺激中刺激氧气和BMP之间在体内和氧气中的刺激质量的刺激效果是否可以改善氧气中的质量，以及是否可以构成了Oxysterol的质量，是否构成了质量的质量。脂肪形成。这些研究将提供有关调节成骨的基本机制和氧化酚的作用的重要新信息，以及未来研究氧甲醇作为对局部且可能是全身性骨变化的潜在新骨诱导剂的指导。