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

基本信息

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
项目类别：
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

项目摘要

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.

项目概要/摘要每年约有 1500 万起骨折，下颌骨支撑着绝大多数颅面骨目前的临床方法，例如颌面固定，是极具侵入性的，并且因此，这项拨款的目的是解决愈合受损的临床需求。实现下颌骨折的转化和临床相关方法需要跨领域的研究。利用生物材料和药物输送方面的专业知识以及对以下方面的理解的学科方法驱动功能性骨修复的机制主要通过软骨内愈合。骨化，其中软骨中间体形成，然后被骨取代。近年来，许多这种现象发生。包括我们在内的研究小组已经发表了重要证据，表明软骨细胞转分化为骨发育和骨折愈合过程中的成骨细胞。软骨细胞的机制。迄今为止，转分化尚未得到彻底探索，但我的初步数据以及先前发表的工作表明β-连环蛋白信号传导是软骨细胞衍生的关键介质已在多种细胞类型中观察到 NGF/TrkA 信号传导对成骨细胞的激活作用。有趣的是，我们的初步数据显示骨折愈伤组织中 NGF 和 TrkA 的表达有所增加。我们的初步数据表明，在软骨期对骨折施用 NGF 会加速在这次研究期间，我的目标是了解 NGF 在软骨细胞转分化中的作用，以及开发一种治疗递送系统，用于局部持续释放“无痛”NGF NGFR100W。该项目的中心假设是，通过 PEGDMA 微粒持续释放 NGFR100W 将通过激活肥大软骨细胞中的β-连环蛋白信号加速软骨内骨折愈合。在第一个目标中，我将基于我们通过工程增强 NGF 治疗小鼠骨修复的初步数据 NGFR100W 洗脱 PEGDMA 微粒可加速愈合。经皮注射到骨折愈伤组织上，然后评估组织成分、生物力学通过使用组织学、显微 CT 成像、三点弯曲测试和体视学来评估强度和愈合率。在第二个目标中，我将确定 NGF 刺激成骨的机制，我将使用离体。用 NGF 培养的骨折愈伤组织衍生软骨系统，用于测量下游标记物通过 RT-qPCR 检测骨生成、血管生成和候选途径（包括 β-Catenin、Sox2 和 Hedgehog）体内 I 将通过穿过 TrkAfl/fl 和有条件地从软骨细胞中删除 TrkA。聚集蛋白聚糖-CreER 转基因小鼠测试骨折期间软骨细胞转分化是否需要 NGF 使用目标 1 中描述的相同功能结果测量进行治疗。