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 先天性和获得的颅面缺陷并不少见。脱矿质骨基质（DBM）已经 广泛用于骨科修复。但是，由于其颗粒性质，更广泛的DBM使用受到限制 灌溉后脱矿化和快速颗粒分散后，导致不可预测的骨诱导率。 粘性赋形剂通常被用来产生稳定的DBM颗粒悬浮液，但此类载体是 快速溶解在体内和成骨成分的局部作用中，例如骨骼 形态发生蛋白（BMP）可能在缺陷部位不期望。尽管外源性BMP可以组合 为了提高DBM的能力，其临床应用需要超生理剂量，并显示出明显的 不利影响。因此，有必要制定替代策略来增强成骨的效力 DBM。这项研究旨在通过将DBM纳入自我修复来增强骨骼再生能力 结合生理稳定性和促稳态特性的动态聚合物网络。在BMP上 刺激，由于天然BMP拮抗剂的表达增强，BMP疗效大大降低了 作为Noggin。因此，这项研究将通过废除BMP进一步提高DBM中存在的BMP的效力 通过RNA干扰Noggin的拮抗作用。细胞来源的外泌体模拟物（EM）将被用作生物 以局部有效的方式传递RNA干扰分子的载体。总体目标 提案是设计一种健壮的骨移植复合材料，该复合材料可以通过整合DBM有效地修复骨缺损 并将其沉默化为聚合物载体系统。为了实现这一目标，我们提出了三个目标。在AIM 1中， 我们将根据植物化学疗法的自组装开发一种可延展的自我修复水凝胶 带有二氧化硅富含二氧化硅的壳聚糖，装饰的植物化学驱动器动态分子 凝胶化和纳米粘土的相互作用与骨诱导特性充当物理交联。通过改变 将设计植物化学与纳米粘土的比例和DBM颗粒的含量，水凝胶/DBM复合材料的含量 并通过评估凝胶化动力学，注射性和自我修复特征来制备。骨诱导 开发的复合材料的活性将在体外和大鼠钙颅缺陷中确定。接下来在AIM 2中，我们将 从Noggin定向的siRNA转染的MSC收集EM，并评估EM的协同作用 DBM诱导的骨形成。我们还将通过点击交联反应将EM与水凝胶结合到水凝胶中，以获取更多 局部和延长的Noggin沉默效应。最后，在AIM 3中，我们将集成DBM并加载 Noggin siRNA进入植物化学和纳米粘土的自我修复水凝胶，并从AIM 1开发并评估 使用A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 下颌缺陷模型。与商业DBM产品相比，将评估成功的骨形成 和重组BMP-2。这些研究的成功完成将确定一种新的策略来改善临床 通过最大化BMP信号传导在DBM介导的骨再生中的活性，通过最大化骨移植的功效。