Osteogenic and angiogenic tissue regeneration to accelerate secondary bone healing during aging

成骨和血管生成组织再生可加速衰老过程中的二次骨愈合

• 批准号: 9980268
• 负责人: HICHAM M DRISSI
• 金额: $ 26.28万
• 依托单位: EMORY UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-08-01 至 2024-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9980268
• 关键词: Acute Myelocytic Leukemia; Adolescent; Age-Months; Aging; Animals; Antibodies; Binding; Biomechanics; Blood Vessels; Bone Regeneration; Bone Resorption; Bone callus; Cells; Charge; Chondrocytes; Clinical; Complex; Control Animal; Data; Dependence; Diabetes Mellitus; Distal; Economics; Emotional; Endothelial Cells; Endothelium; Family; Femoral Fractures; Femur; Fracture; Fracture Healing; Frequencies; Gene Expression; Genotype; Goals; Harvest; Hematopoiesis; Histologic; Histology; Homeostasis; Human; Hydrogels; Image; Impaired healing; Impairment; In Vitro; Interleukin-17; Lead; Mechanics; Mediating; Mesenchymal; Mesenchymal Differentiation; Mesenchymal Stem Cells; Metabolic Diseases; Metabolic dysfunction; Modeling; Molecular; Molecular Target; Mus; Nail plate; Neck; Osteoblasts; Osteogenesis; Osteoporosis; Osteoporotic; Patients; Periosteal Cell; Periosteum; Pharmaceutical Preparations; Physiologic Ossification; Population; Process; Productivity; Proteins; RUNX3 gene; Radial; Radius Fractures; Regulation; Regulatory Pathway; Reporting; Repression; Risk; Roentgen Rays; Role; Safety; Signal Transduction; Site; Skeletal Development; Small Interfering RNA; T cell differentiation; T-Lymphocyte; Testing; Therapeutic; Time; Tissue Engineering; Tissues; Torsion; Translational Research; Tube; age related; aged; aging population; angiogenesis; bone; bone healing; bone mass; cartilaginous; comorbidity; design; experimental study; fragility fracture; healing; humerus; in vivo; ineffective therapies; laser capture microdissection; limb fracture; loss of function; microCT; mortality; nanoparticle; novel; older patient; osteogenic; phenotypic biomarker; progenitor; promoter; receptor; regenerative; repaired; siRNA delivery; spine bone structure; stem cells; success; tissue regeneration; transcription factor

Clinical premise: Aging is associated with increased frequency of fragility fractures, which often result in significant economic and emotional burden. Ineffective treatment of these fractures leads to lost productivity and often increased expenses of fracture-associated complications, including increased mortality. Moreover, the risk of impaired or delayed bony union is further enhanced by patient co-morbidities and metabolic diseases such as diabetes or osteoporosis. The vast majority of these fractures target the vertebrae, proximal femur, distal femur, proximal humerus and distal radius. Whether they are treated operatively (i.e. nailing a femur fracture or plating a distal radius fracture) or non-operatively (i.e. cast or sling), these fractures heal via endochondral ossification in a process called secondary fracture healing. Various bone anabolic drugs, which were initially designed to treat osteoporotic patients, have been tested to enhance fracture repair. However, despite their established efficacy in increasing homeostatic bone mass, limited success was achieved in their clinical use to accelerate fracture repair. Therefore, identifying novel molecular targets to enhance secondary bone repair remains of paramount importance. The objective of this translational research application is to accelerate secondary bone repair in vivo by targeting novel regulatory pathways in aging mice that enhance periosteal cell-induced osteogenesis and angiogenesis during fracture callus formation. Scientific premise: We provide compelling preliminary evidence of the following: 1. Runx3 is expressed in mesenchymal cells of both human and murine fractures. 2. Runx3 expression in the callus decreases as the fracture heals. 3. Conditional deletion of Runx3 in periosteal cells (cKO) results in enhanced secondary bone healing through increased osteogenesis and angiogenesis. 4. Runx3 deletion in the periosteum resulted in increased expression of IL-17a receptor (IL-17ra) in fractured femurs of cKO mice compared to controls animals. 5. Runx3 directly binds to the proximal promoter of IL-17ra. Finally, 6. Runx3 protein levels remain elevated in mesenchymal cells in fracture calluses of aged compared to juvenile mice. Our central hypothesis is that repression of Runx3 in periosteal cells will accelerate secondary fracture healing in aging mice through activation of IL-17 signaling in mesenchymal cell populations. Specific objectives: We will establish that Runx3 deletion in periosteal cells accelerates bone regeneration and secondary bone healing in aging mice through enhanced bone formation and angiogenesis at the fracture site. (Aim 1). We will then demonstrate that Runx3 delays callus bone formation and vascular invasion by age- dependently inhibiting IL-17ra signaling in mesenchymal cells. (Aim 2A). Finally, we will use hydrogels to locally deliver Runx3 siRNA-complexed nanoparticles and examine the efficacy and safety of this therapeutic approach in accelerating senile fracture healing (Aim 2B).

临床前提：衰老与脆性骨折的频率增加有关，这通常会导致 沉重的经济和情感负担。对这些裂缝的无效处理导致生产力损失， 通常会增加与糖尿病相关的并发症的费用，包括增加死亡率。此外，风险 骨愈合受损或延迟的可能性会因患者的合并症和代谢性疾病而进一步增强， 糖尿病或骨质疏松症。绝大多数骨折都是针对椎骨股骨近端股骨远端， 肱骨近端和桡骨远端。是否接受手术治疗（即，股骨骨折钉固定或钢板固定 桡骨远端骨折）或非手术（即石膏或吊带），这些骨折通过软骨内骨化愈合 这一过程被称为继发性骨折愈合。各种骨合成代谢药物，最初设计用于 治疗骨质疏松症患者，已被测试，以加强骨折修复。然而，尽管他们建立了 虽然它们在增加稳态骨量方面的功效有限，但在其临床应用中取得的成功有限， 骨折修复因此，鉴定新的分子靶点以增强继发性骨修复仍然是骨修复的关键。 至关重要这项转化研究应用的目的是加速再生骨 通过靶向衰老小鼠中的新调控途径进行体内修复， 骨折骨痂形成过程中的骨生成和血管生成。 科学前提：我们提供了以下令人信服的初步证据：1。Runx 3表示为 人和鼠骨折处的间充质细胞。2. Runx 3在愈伤组织中的表达随着 骨折愈合。3.骨膜细胞中Runx 3的条件性缺失（cKO）导致增强的继发性骨 通过增加骨生成和血管生成来愈合。4.骨膜中Runx 3的缺失导致 与对照动物相比，cKO小鼠骨折股骨中IL-17 a受体（IL-17 ra）的表达增加。 5. Runx 3直接结合IL-17 ra的近端启动子。最后，6。Runx 3蛋白水平仍然升高， 间充质细胞在骨折骨痂中的作用。 我们的中心假设是，骨膜细胞中Runx 3的抑制将加速二次骨折愈合 通过激活间充质细胞群中的IL-17信号传导在衰老小鼠中的作用。 具体目标：我们将确定骨膜细胞中Runx 3缺失加速骨再生， 通过增强骨折部位的骨形成和血管生成，在衰老小鼠中实现继发性骨愈合。 (Aim 1）。然后，我们将证明Runx 3通过年龄延迟骨痂骨形成和血管侵袭- 依赖性抑制间充质细胞中的IL-17 ra信号传导。(Aim 2A）。最后，我们将使用水凝胶局部 递送Runx 3 siRNA复合纳米颗粒，并检查这种治疗方法的有效性和安全性 加速老年性骨折愈合（目标2B）。