Local Delivery of Neurogenic Factors via Polymeric Microparticles for Enhanced Endochondral Bone Repair in the Mandible

通过聚合物微粒局部递送神经源性因子以增强下颌骨软骨内骨修复

• 批准号: 9895427
• 负责人: Kevin Omar Rivera
• 金额: $ 4.01万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-03-01 至 2021-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9895427
• 关键词: Accelerated Phase; Accounting; Acute; Address; Adopted; Affinity; Applications Grants; Biocompatible Materials; Biological; Biological Assay; Biological Availability; Biomechanics; Bone Density; Bone Development; Bone Regeneration; Bone callus; Cartilage; Chondrocytes; Clinical; Clinical Trials; Communication; Coupled; Data; Dependence; Development; Drug Delivery Systems; Engineering; Erinaceidae; Esthetics; Fellowship; Food; Fracture; Fracture Healing; Goals; Grant; Harvest; Histology; Image; Impaired healing; In Vitro; Injectable; Injury; Invaded; Kinetics; Life; Ligands; Link; Mandible; Mandibular Fractures; Mastication; Measures; Mediator of activation protein; Methods; Molecular; Mus; NGFR Protein; Natural regeneration; Nerve Growth Factors; Neurotrophic Tyrosine Kinase Receptor Type 1; Operative Surgical Procedures; Osteoblasts; Osteogenesis; Outcome Measure; Painless; Pathway interactions; Patients; Peripheral Nerves; Phenotype; Physiologic Ossification; Polyethylene Glycols; Polymers; Prevalence; Process; Proteins; Publishing; Regulation; Role; Signal Transduction; System; Technology; Testing; Therapeutic; Tissues; Transgenic Mice; Translating; United States; Vascular Endothelial Cell; Western Blotting; Work; aggrecan; angiogenesis; base; beta catenin; bicinchoninic acid; bone; bone strength; cartilaginous; cell type; chondrocyte stimulating factor; clinically relevant; controlled release; cost effective; craniofacial bone; crosslink; density; effective therapy; experimental study; facial disfigurement; functional outcomes; healing; in vivo; maxillofacial; microCT; mineralization; mutant; neurotransmission; neurovascular; new therapeutic target; novel therapeutic intervention; oral communication; premature; prevent; repaired; sample fixation; transdifferentiation; treatment response

Project Summary/Abstract There are approx. 15 million bone fractures annually and the mandible sustains the vast majority of craniofacial bone fractures. Currently clinical approaches, such as maxillofacial fixation, are exceedingly invasive and the prevalence of impaired healing remains. Therefore, the objective of this grant is to address the clinical need for a translational and clinically relevant approach to mandibular fractures. Accomplishing this goal requires cross- disciplinary methods that harness expertise in biomaterials and drug delivery coupled with an understanding of the mechanisms that drive functional bone repair. The mandible primarily heals through endochondral ossification, in which a cartilage intermediate forms and is later replaced by bone. In recent years, many groups, including ours, have published significant evidence to show that chondrocytes transdifferentiate into osteoblasts during bone development and fracture healing. The mechanisms underlying chondrocyte transdifferentiation have thus far not been thoroughly explored. However, my preliminary data, along with previously published work, indicate that β-catenin signaling is a critical mediator of chondrocyte-derived osteoblastogenesis. Activation of β-catenin by NGF/TrkA signaling has been observed in various cell types and interestingly; our preliminary data show an increase in NGF and TrkA expression in fracture calluses. Finally, our preliminary data show that NGF administration onto fractures during the cartilaginous phase accelerates bone repair. During this fellowship I aim to understand the role of NGF in chondrocyte transdifferentiation, and develop a therapeutic delivery system for local and sustained release of a “painless” NGF, NGFR100W. The central hypothesis for this project is that sustained release of NGFR100W via PEGDMA microparticles will accelerate endochondral fracture healing by activating β-catenin signaling in hypertrophic chondrocytes. In the first Aim I will build on our preliminary data of enhanced bone repair in NGF-treated mice by engineering NGFR100W-eluting PEGDMA microparticles to accelerate healing. NGFR100W-loaded PEGDMA microparticles will be injected percutaneously onto fracture calli followed by assessment of tissue composition, biomechanical strength, and rate of healing by using histology, microCT imaging, three-point bending tests, and stereology. In the second Aim, I will determine the mechanism by which NGF stimulates osteogenesis. I will use an ex vivo system of fracture callus-derived cartilage cultured with NGF to measure downstream markers of osteogenesis, angiogenesis, and candidate pathways including β-Catenin, Sox2, and hedgehog by RT-qPCR and western blot. In vivo I will conditionally delete TrkA from chondrocytes by crossing the TrkAfl/fl and aggrecan-CreER transgenic mice to test if NGF is required for chondrocyte transdifferentiation during fracture healing using the same functional outcome measures described in Aim 1.

项目摘要/摘要 大约有。每年有1500万骨骨折，下颌骨可维持绝大多数颅面 骨断裂。目前 尚无医治的患病率仍然存在。因此，这笔赠款的目的是满足临床需求 翻译和临床相关的下颌骨折方法。实现这一目标需要交叉 利用生物材料和药物输送方面的专业知识的纪律方法以及对 驱动功能骨修复的机制。下颌骨通过内软骨治愈 骨化，其中一种软骨中间形式，后来被骨骼代替。近年来，许多 包括我们在内的群体已经发表了大量证据，表明软骨细胞转变为 成骨细胞在骨骼发育和断裂愈合过程中。软骨细胞的基础机制 到目前为止，尚未彻底探索转变。但是，我的初步数据以及 先前发表的工作，表明β-catenin信号传导是软骨细胞衍生的关键介体 成骨细胞生成。在各种细胞类型中，已经观察到通过NGF/TRKA信号激活β-catenin的激活 有趣的是;我们的初步数据表明，断裂库库中NGF和TRKA表达的增加。最后， 我们的初步数据表明，在软骨相期间，NGF给予裂缝加速 骨修复。在此奖学金期间 开发一种治疗性输送系统，用于局部和持续释放“无痛” NGF，NGFR100W。这 该项目的中心假设是通过PEGDMA微粒持续释放NGFR100W 通过激活肥厚软骨细胞中的β-catenin信号传导来加速内软骨骨折的愈合。 在第一个目标中，我将建立在通过工程的NGF治疗小鼠中增强骨修复的初步数据的基础上 NGFR100W洗脱PEGDMA微粒以加速愈合。 NGFR100W负载的PEGDMA微粒将 将经习惯注射到骨折卡利上，然后评估组织组成，生物力学 通过使用组织学，MicroCT成像，三分弯曲测试和立体学的强度和愈合率。 在第二个目标中，我将确定NGF刺激成骨的机制。我将使用ex vivo 用NGF培养的断裂愈伤组织的软骨系统，以测量下游标记 成骨，血管生成和候选途径，包括β-catenin，Sox2和刺猬，RT-QPCR 和Western印迹。在体内，我将通过越过trkafl/fl和 Aggrecan-creer转基因小鼠测试裂缝期间软骨细胞转分节的NGF是否需要NGF 使用AIM 1中描述的相同功能结果度量的愈合。