Hydrogel delivery of DBM and exosome mimetics for bone repair

水凝胶递送 DBM 和外泌体模拟物用于骨修复

• 批准号: 10412361
• 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: 2022
• 资助国家: 美国
• 起止时间: 2022-08-10 至 2027-05-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10412361
• 关键词: Adverse effects; Autologous; Autologous Transplantation; BMP2 gene; Blood; Bone Matrix; Bone Morphogenetic Proteins; Bone Regeneration; Bone Transplantation; Calvaria; Catechols; Cells; Characteristics; Chemistry; Chitosan; Craniofacial Abnormalities; Crosslinker; Defect; Dose; Engineering; Environment; Excipients; Feedback; Goals; Gold; Harvest; Health; Histologic; Hydrogels; Implant; In Situ; In Vitro; Injectable; Irrigation; Kinetics; Mandible; Mediating; Mesenchymal Stem Cells; Minerals; Modeling; Nature; Orthopedics; Osteogenesis; Particulate; Persons; Physiological; Phytochemical; Polymers; Process; Property; Public Health; RNA Interference; Rattus; Reaction; Recombinants; Regenerative capacity; Repair Material; Research; Safety; Signaling Protein; Silicon Dioxide; Site; Small Interfering RNA; Suspensions; System; Therapeutic; Work; antagonist; base; biomechanical test; bone; bone healing; bone repair; clinical application; clinical efficacy; cortical bone; crosslink; delivery vehicle; demineralization; design; exosome; extracellular vesicles; healing; implantation; improved; intercellular communication; intermolecular interaction; microCT; mimetics; nanocarrier; nanocomposite; nanosheet; osteogenic; osteoinductive factor; particle; reconstruction; repaired; self assembly; skeletal; treatment site; vector

Abstract Congenital and acquired craniofacial defects are not uncommon. Demineralized bone matrix (DBM) has been widely used for the orthopedic repair. However, more extensive use of DBM is limited due to its particulate nature after demineralization and rapid particle dispersion following irrigation, resulting in unpredictable osteoinductivity. Viscous excipients are often employed to produce stable suspension of DBM particles, but such carriers are rapidly dissolved in a body and the localized effect of osteogenic components present in DBM such as bone morphogenetic proteins (BMPs) may not expect at the defect site. Although exogenous BMPs can be combined to enhance DBM capacity, its clinical application requires supraphysiological doses and has revealed significant adverse effects. Thus, there is a need to develop alternative strategies that can enhance the osteogenic potency of DBM. This study seeks to enhance bone regeneration capacity by incorporating DBM into a self-healing dynamic polymer network that combines physiological stability and pro-osteogenic properties. Upon BMP stimulation, BMP efficacy is greatly reduced due to the enhanced expression of natural BMP antagonists such as noggin. Thus, this study will further enhance the potency of BMPs present in DBM by abrogation of BMP antagonism through RNA interference for noggin. Cell-derived exosome mimetics (EM) will be applied as a bio- vector to deliver RNA interference molecules in a localized and efficient manner. The overall objective of this proposal is to devise a robust bone graft composite that can effectively repair bone defects by integrating DBM and noggin-silencing EM into polymeric carrier systems. To achieve this goal, we propose three aims. In Aim 1, we will develop a malleable and self-healing hydrogel based on the self-assembly of phytochemical-grafted chitosan with silica-rich nanoclays, where the decorated phytochemical drives dynamic intermolecular interactions for gelation and nanoclay works as physical crosslinker with osteoinductive property. By varying the ratio of phytochemical to nanoclay and the content of DBM particles, hydrogel/DBM composites will be designed and prepared by evaluating gelation kinetics, injectability and self-healing characteristics. The osteoinductive activity of the developed composite will be determined in vitro and in a rat calvarial defect. Next in Aim 2, we will harvest EM from MSCs transfected with noggin-directed siRNA and evaluate the synergistic effect of EM on DBM-induced bone formation. We will also conjugate EM to hydrogels via a click crosslinking reaction for more localized and prolonged noggin silencing effects. Finally in Aim 3, we will integrate DBM and EM loaded with noggin siRNA into self-healing hydrogels of phytochemical and nanoclay developed from Aim 1 and evaluate the ability of the bone graft composite to promote bone regeneration in more challenging environments using a mandibular defect model. Successful bone formation will be evaluated compared with commercial DBM products and recombinant BMP-2. Successful completion of these studies will identify a new strategy to improve clinical efficacy of current bone grafting by maximizing activity of BMP signaling in DBM-mediated bone regeneration.

抽象的 先天性和后天性颅面缺陷并不罕见。脱矿骨基质（DBM） 广泛用于骨科修复。然而，由于 DBM 的颗粒性质，其更广泛的使用受到限制 经过脱盐和冲洗后颗粒快速分散，导致不可预测的骨诱导性。 粘性赋形剂通常用于产生稳定的 DBM 颗粒悬浮液，但此类载体 快速溶解在体内以及 DBM 中存在的成骨成分（例如骨）的局部效应 形态发生蛋白 (BMP) 可能不会出现在缺陷部位。虽然外源性 BMP 可以联合使用 为了增强 DBM 能力，其临床应用需要超生理剂量，并且已经揭示了显着的 不良影响。因此，需要开发可以增强成骨效力的替代策略 DBM 的。这项研究旨在通过将 DBM 纳入自愈系统中来增强骨再生能力 动态聚合物网络结合了生理稳定性和促成骨特性。基于BMP 刺激后，由于天然 BMP 拮抗剂的表达增强，BMP 功效大大降低，例如 作为头。因此，本研究将通过废除 BMP 进一步增强 DBM 中 BMP 的效力 通过RNA干扰对noggin产生拮抗作用。细胞衍生的外泌体模拟物（EM）将作为生物 载体以局部且有效的方式递送RNA干扰分子。本次活动的总体目标 建议设计一种坚固的骨移植复合材料，通过整合 DBM 来有效修复骨缺损 和头沉默电磁进入聚合物载体系统。为了实现这一目标，我们提出三个目标。在目标 1 中， 我们将开发一种基于植物化学接枝物自组装的可塑性和自修复水凝胶 壳聚糖与富含二氧化硅的纳米粘土，其中修饰的植物化学物质驱动动态分子间 凝胶化和纳米粘土的相互作用作为具有骨诱导特性的物理交联剂。通过改变 将设计植物化学物质与纳米粘土的比例以及DBM颗粒、水凝胶/DBM复合材料的含量 并通过评估凝胶动力学、可注射性和自修复特性来制备。骨诱导 所开发的复合材料的活性将在体外和大鼠颅骨缺损中进行测定。接下来的目标 2，我们将 从转染 noggin 的 siRNA 的 MSC 中收获 EM，并评估 EM 对 DBM 诱导骨形成。我们还将通过点击交联反应将 EM 与水凝胶结合，以获得更多信息 局部和长期的头蛋白沉默效应。最后在目标 3 中，我们将集成 DBM 和 EM 并加载 将 noggin siRNA 植入从 Aim 1 开发的植物化学物质和纳米粘土的自愈水凝胶中并进行评估 骨移植复合材料在更具挑战性的环境中促进骨再生的能力 下颌骨缺损模型。将与商业 DBM 产品进行比较来评估成功的骨形成 和重组BMP-2。这些研究的成功完成将确定改善临床的新策略 通过最大化 DBM 介导的骨再生中 BMP 信号的活性来提高当前骨移植的功效。