Identifying the superior ossification pathway for tissue engineered approaches to long bone repair

确定组织工程方法修复长骨的最佳骨化途径

• 批准号: 10591573
• 负责人: J. Kent Leach
• 金额: $ 37.99万
• 依托单位: UNIVERSITY OF CALIFORNIA AT DAVIS
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-04-01 至 2026-02-28
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10591573
• 关键词: 3-Dimensional; Acceleration; Address; Adhesives; Adsorption; Affect; Age; Allogenic; Angiogenic Factor; Apoptosis; Autologous; BMP2 gene; Binding; Biological Assay; Biomimetics; Bone Regeneration; Bone Transplantation; Cartilage; Cell Adhesion; Cell Differentiation process; Cell Survival; Cell Therapy; Cell Transplantation; Cell physiology; Cell secretion; Cells; Chondrogenesis; Clinical; Cues; Data; Defect; Development; Disease; Excision; Exhibits; Extracellular Matrix; Fracture; Growth Factor; Growth Factor Receptors; Health; Histology; Immune; Impairment; Implant; In Situ; In Vitro; Individual; Integrins; Intervention; Longevity; Methods; Mitogens; Musculoskeletal; Natural regeneration; Osteogenesis; Outcome; Pathway interactions; Patients; Phenotype; Physiologic Ossification; Publishing; Quality of life; Recombinant Growth Factor; Research; Role; Safety; Signal Transduction; Testing; Therapeutic; Tissue Engineering; Tissues; Transplantation; Trauma; bone; bone healing; bone repair; cartilage implant; cartilage transplantation; cell growth; disease transmission; dosage; healing; implantation; innovation; intramembranous bone formation; long bone; mesenchymal stromal cell; morphogens; non-invasive imaging; novel; novel strategies; osteogenic; repair function; repaired; response; side effect; skeletal; stem cells; synergism; tumor

PROJECT SUMMARY Musculoskeletal health is a key determinant of mobility and quality of life which affects every individual, regardless of age. Up to 20% of the 6 million fractures occurring annually in the US will result in nonunion or slow healing and require intervention for bone regeneration. Mesenchymal stromal cells (MSCs) are one alternative to bone grafts because of their osteogenic, chondrogenic, and proangiogenic potential. Compared to monodisperse cells, MSC spheroids better resist apoptosis and secrete 100-fold higher levels of angiogenic factors while retaining their multipotency. However, MSC spheroids are not yet sufficient to bridge large bone defects, suggesting the need for effective programming methods to enhance their bone-forming potential. Furthermore, it is unclear whether bone healing is more effective by jumpstarting cartilage formation or attempting to induce osteogenic differentiation of resident or transplanted cells. Local delivery of inductive growth factors such as BMP-2 and TGF-b1 accelerates tissue formation, but the necessary supraphysiological concentrations and associated complications impair their widespread clinical use. Our data demonstrate that MSC spheroids loaded with cell-secreted extracellular matrix (ECM) are more responsive to potent mitogens and exhibit enhanced osteogenic and chondrogenic differentiation while using markedly reduced dosages and reducing contraindications. Thus, our central hypothesis is that MSC spheroids can be differentiated in situ toward the osteogenic or chondrogenic lineage by presenting inductive cues adsorbed to incorporated ECM, which will yield potent cellular building blocks to regenerate large lost bone volumes. Aim 1. Adapt cell- secreted ECM to locally present inductive factors to MSCs within spheroids to enhance osteogenic or chondrogenic differentiation. We will test the role of ECM quantity and BMP-2 and TGF-b1 dosage on growth factor retention and presentation of loaded morphogens and correlating their resulting effect on osteogenesis and chondrogenesis in vitro. Aim 2. Potentiate MSC osteogenic or chondrogenic differentiation by manipulating ECM-driven morphogen presentation. We will identify and quantify changes in integrin expression and growth factor receptor activity in MSC spheroids containing ECM-adsorbed BMP-2 or TGF-b1. We will then assess changes in MSC differentiation when decoupling the synergy of cell adhesion and growth factor availability. Aim 3. Establish the therapeutic potential of ECM-adsorbed exogenous morphogens to instruct MSC spheroids in situ for bone formation. We will determine the capacity of MSC spheroids containing ECM- adsorbed BMP-2 or TGF-b1 to persist, undergo osteogenic or chondrogenic differentiation in situ, and repair large bone defects. We will use noninvasive imaging and histology to describe the superior pathway to promote robust bone formation in long bone defects. The proposed research is innovative because it provides a novel strategy to reduce the quantity of recombinant growth factors needed to guide cell function, while establishing whether MSCs directed toward cartilage or bone achieve faster bone repair in long bones.

项目总结 肌肉骨骼健康是影响每个人行动能力和生活质量的关键决定因素， 无论年龄大小。在美国每年发生的600万例骨折中，高达20%将导致骨不连或 愈合缓慢，需要干预以促进骨骼再生。间充质基质细胞(MSCs)是 可替代骨移植，因为它们具有成骨、成软骨和促血管生成的潜能。相比较 对于单分散的细胞，MSC球体更好地抵抗凋亡，并分泌100倍以上的血管生成 因素，同时保持其多功能性。然而，间充质干细胞球体还不足以桥接大块骨。 缺陷，提示需要有效的编程方法来增强其成骨潜力。 此外，目前还不清楚骨愈合是通过启动软骨形成还是通过启动软骨形成更有效。 试图诱导常驻细胞或移植细胞的成骨分化。感应性的本地交付 骨形态发生蛋白-2和转化生长因子-β1等生长因子可加速组织形成，但必要的超生理学 浓度和相关的并发症阻碍了它们的广泛临床应用。我们的数据表明 装载有细胞分泌的细胞外基质(ECM)的MSC球体对强有力的有丝分裂原更敏感 表现出增强的成骨和软骨分化，同时使用显著减少的剂量和 减少禁忌症。因此，我们的中心假设是MSC球体可以在原位分化。 通过提供吸附到被结合的ECM的诱导线索来朝向成骨或成软骨谱系， 这将产生强有力的细胞构建块来再生大量丢失的骨体积。目标1.调整细胞- 分泌ECM在球体内局部向MSCs递送诱导因子，促进成骨或 软骨细胞分化。检测细胞外基质用量和BMP-2、TGF-β1用量对生长的影响。 负载形态因子的保留和呈递及其对成骨的影响 和体外软骨形成。目的2.通过以下方式促进MSC成骨或成软骨分化 操纵ECM驱动的形态生成物呈现。我们将识别和量化整合素表达的变化 以及含有ECM吸附的BMP-2或转化生长因子-β1的MSC球体中的生长因子受体活性。我们会 然后评估去偶联细胞黏附和生长因子协同作用时间充质干细胞分化的变化 可用性。目的3.建立细胞外基质吸附外源形态因子的治疗潜力 MSC球体原位成骨。我们将测定含有ECM-的MSC球体的容量- 吸附BMP-2或转化生长因子-β1持续存在，在原位进行成骨或软骨分化，并修复 大块的骨缺损处。我们将使用非侵入性成像和组织学来描述 促进长骨缺损处强健的骨形成。拟议的研究具有创新性，因为它提供了 一种新的策略，以减少引导细胞功能所需的重组生长因子的数量，同时 确定骨髓间充质干细胞是向软骨还是骨定向，可以更快地修复长骨。