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: 9761343
• 负责人: Kevin Omar Rivera
• 金额: $ 4.12万
• 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 2021-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9761343
• 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 wound 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.

项目总结/文摘