Tribbles homolog 3 and BMP-2 induced bone formation

Tribbles 同源物 3 和 BMP-2 诱导骨形成

• 批准号: 10165689
• 负责人: Min Lee
• 金额: $ 37.05万
• 依托单位: UNIVERSITY OF CALIFORNIA LOS ANGELES
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-06-08 至 2023-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10165689
• 关键词: Adverse effects; BMP2 gene; Binding; Bone Morphogenetic Proteins; Bone Regeneration; Cell Differentiation process; Clinical; Complement; Cyst; DNA; Data; Defect; Development; Dose; Employment; Feedback; GTP-Binding Protein alpha Subunits, Gs; Gene Transfer; Genes; Genetic Transcription; Goals; Health; Histologic; Homologous Gene; In Vitro; Liposomes; Mandible; Mechanics; Mediating; Mesenchymal; Mesenchymal Differentiation; Mesenchymal Stem Cells; Modality; Modeling; Molecular Target; Osteoblasts; Osteogenesis; PPAR gamma; Pathway interactions; Phospholipids; Play; Proteins; Proteolysis; Public Health; RNA Interference; Rattus; Research; Role; Safety; Signal Transduction; Small Interfering RNA; Structure; System; Testing; Therapeutic; Transfection; Treatment Efficacy; Ubiquitin; Viral Insertional Mutageneses; adverse outcome; base; bone; bone morphogenetic protein receptors; clinical application; clinical efficacy; clinical translation; improved; in vitro activity; knock-down; lipid biosynthesis; microCT; milligram; nanocarrier; nanocomplexes; novel; osteogenic; osteogenin; osteoinductive factor; overexpression; particle; response; skeletal; small molecule; therapeutic gene

Abstract Although bone morphogenetic protein-2 (BMP-2) is believed to be the most potent osteoinductive factor available for bone regeneration, its clinical application requires supraphysiological BMP doses that increase inappropriate adipogenesis and cyst-like bone formation. Therefore, recent promising alternative strategies are toward promoting pro-osteogenic activity of BMPs while simultaneously suppressing their adverse effects. Recent studies suggest important roles of tribbles homologs proteins in development and cellular differentiation. In response to BMP stimulation, in particular, tribbles homolog 3 (Trb3) is dissociated from BMP receptor and degrades Smad ubiquitin regulatory factor 1 (Smurf1), a negative regulator of BMP receptor-regulated Smads. Moreover, Trb3 has been shown to bind and suppress peroxisome proliferator-activated receptor-γ (PPARγ), a master regulator of adipogenesis. Thus, Trb3 may be a promising molecular target to enhance BMP-2 induced osteogenesis and reduce adverse adipogenesis. Upon BMP stimulation, however, BMP efficacy is greatly reduced due to the enhanced expression of natural BMP antagonists to auto-regulate endogenous BMP-2 levels. Thus, the potency of Trb3 in BMP treatments can be enhanced by inhibiting expression of BMP antagonists such as noggin. The objective of this study is to investigate whether overexpression of Trb3 and simultaneous abrogation of BMP antagonism can enhance BMP-induced osteogenesis and bone formation quality while lowering exogenous BMP requirement. The specific hypothesis is that the augmentation of Trb3 expression combined with the employment of noggin suppression can enhance bone formation by activation of Smad pathway and suppression of PPARγ, tested in the following aims. In Aim 1, we will evaluate whether Trb3 overexpression can synergistically enhance bone formation with BMP-2 in a rat critical size mandibular defect (MD). We will also apply high dose BMP-2 to induce adverse cyst-like bone formation in the MD model and test whether Trb3 overexpression can reduce the BMP-2 induced adverse outcomes and improve bone formation quality. In addition, we will determine whether the positive Trb3 effects are dependent on Smurf1 and PPARγ activities in vitro. Next in Aim 2, we will stimulate endogenous BMP signaling by downregulating noggin using an RNAi strategy and evaluate the synergistic effect of noggin suppression on Trb3-induced bone formation in the MD model. We will subsequently determine whether Trb3 expression + noggin suppression can lower total BMP-2 dose requirements or even eliminate use of exogenous BMP-2 without compromising osteogenic efficacy. Finally in Aim 3, we will further elaborate our complementary bone formation strategy (Trb3 expression + noggin suppression) toward clinical translations via use of appropriate carriers that deliver these therapeutic genes in much safer and efficient manners based on our novel non-phospholipid liposomal systems. Successful completion of these studies will identify a new strategy to improve clinical efficacy and safety of current BMP therapeutics by regulating expression of Trb3 and noggin for enhanced bone repair.

摘要 尽管骨形态发生蛋白-2(BMP-2)被认为是最有效的骨诱导因子 可用于骨再生，其临床应用需要增加超生理剂量的BMP 不适当的脂肪生成和囊状骨形成。因此，最近前景看好的替代战略是 促进BMPs的成骨活性，同时抑制其不良影响。 最近的研究表明，Tribble同源蛋白在发育和细胞分化中发挥着重要作用。 特别是，作为对BMP刺激的反应，Tribble Homolog 3(Trb3)与BMP受体解离，并且 降解BMP受体调节的Smads的负调控因子Smad泛素调节因子1(SMurf1)。 此外，trb3还被证明可以结合和抑制过氧化物酶体增殖物激活受体γ(PPARγ)。 脂肪生成的主要调节者。因此，Trb3可能是增强BMP-2诱导的分子靶点。 促进成骨，减少不利的脂肪生成。然而，在BMP刺激下，BMP的效果显著 减少是由于增强了天然BMP拮抗剂的表达，以自动调节内源性BMP-2 级别。因此，可以通过抑制BMP的表达来增强Trb3在BMP治疗中的效力 像诺金这样的对手。本研究的目的是研究Trb3和Trb3的过度表达是否 同时取消BMP拮抗剂可促进BMP诱导的成骨和骨形成 在降低外源性BMP要求的同时提高质量。具体的假设是Trb3的增强 表达结合使用noggin抑制可通过激活 Smad途径和抑制PPARγ，在以下目的进行了测试。在目标1中，我们将评估 Trb3过表达与BMP-2协同促进大鼠下颌骨临界大小的骨形成 缺陷(MD)。我们还将在MD模型中应用大剂量BMP-2来诱导不利的囊状骨形成 并测试Trb3过表达是否可以减少BMP-2诱导的不良结局，改善骨骼 阵型质量。此外，我们将确定Trb3的正效应是否依赖于S-f1和 PPARγ的体外活性。接下来，在目标2中，我们将通过下调noggin来刺激内源性BMP信号 使用RNAi策略和评价noggin抑制Trb3诱导的骨的协同作用 在MD模型中形成。我们随后将确定Trb3表达+noggin抑制 可以降低BMP-2的总剂量要求，甚至在不影响使用外源性BMP-2的情况下取消使用 成骨功效。最后，在目标3中，我们将进一步阐述我们的补充骨形成策略。 (Trb3表达+noggin抑制)通过使用适当的载体进行临床翻译 基于我们的新型非磷脂脂质体，这些治疗基因以更安全和有效的方式 系统。这些研究的成功完成将确定一种新的战略，以提高临床疗效和 通过调节trb3和noggin的表达来增强骨修复的现有骨形态发生蛋白疗法的安全性。