Targeting angiogenesis for fracture nonunion treatment under inflammatory diseases

靶向血管生成治疗炎症性疾病下的骨折不愈合

基本信息

批准号：
10437928
负责人：
Jianjun Guan
金额：
$ 55.96万
依托单位：
WASHINGTON UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2020
资助国家：
美国
起止时间：
2020-09-09 至 2026-06-30
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10437928
关键词：
Address Affect Biocompatible Materials Bone callus CXCL12 gene Cell physiology Cells Chondrocytes Chronic Clinical Clinical Research DNA Methylation DNA Modification Methylases DNMT3B gene Data Defect Diabetes Mellitus Disease Down-Regulation Elderly Endothelial Cells Enzymes Epigenetic Process Failure Fracture Gene Expression Health Care Costs Human Impairment In Vitro Inflammation Inflammatory Interleukin-1 beta K/BxN model Kinetics Knowledge Lead Ligands Mediating Methylation Molecular Mus Operative Surgical Procedures Pathway interactions Patients Pharmacology Population Procedures Process Rheumatoid Arthritis Role Serum Signal Transduction Smoking Therapeutic Therapeutic Effect Therapeutic Intervention Tube United States Work angiogenesis biodegradable scaffold bone fracture repair cell motility chemokine comorbidity cytokine diabetic disability efficacy evaluation epigenome experience gain of function healing improved in vivo loss of function novel novel therapeutic intervention older patient osteopontin protective effect restoration scaffold systemic inflammatory response therapeutically effective

项目摘要

ABSTRACT Fracture nonunion poses a significant clinical problem. In the United States, approximately 1.6 million bone fractures encounter prolonged healing or nonunion each year. Fracture nonunion treatment usually involves complicated and massive procedures in practice, and sometimes needs multiple surgeries, therefore increases the cost of health care and results in marked patient disability. The major population bearing with these clinical complications are patients with inflammatory conditions, e.g, elder patients, smoking, diabetic or rheumatoid arthritis (RA) patients, highlighting the potential deleterious role of chronic systemic inflammation in fracture r epair. The overarching hypothesis of this proposal is that chronic inflammation results in fracture nonunion through Dnmt3b downregulation mediated angiogenesis defect, and local delivery of OPN and CXCL12 restores angiogenesis and fracture repair under inflammatory conditions. This hypothesis is supported by our preliminary data wherein we show that Dnmt3b is highly expressed in fracture callus during fracture repair and Dnmt3b is the major DNA methyltransferase (Dnmt) responsive to cytokines in MPCs. Relevant to our proposal, we provide evidence that inflammatory signals inhibit Dnmt3b in an NF-κB-dependent manner. Consistently, mice with Dnmt3b loss-of-function (LOF) in chondrocytes display impaired angiogenesis and fracture repair; and Dnmt3b gain-of-function (GOF) in chondrocytes shows protective effect from inflammation in vitro and accelerates fracture repair in mice. Mechanistically, angiogenesis defect mediated by inflammation and Dnmt3b LOF coincide with downregulation of OPN (Osteopontin) and CXCL12 (C-X-C Motif Chemokine Ligand 12) and exogenous OPN and CXCL12 can restore angiogenesis capacity in vitro. To further examine the efficacy of local delivery of OPN and CXCL12 in vivo, we have developed an optimized biomaterial sheet loaded with OPN and CXCL12 and showed a robust angiogenesis process and a restoration of fracture union in RA mice. Three main Specific Aims are proposed. Specific Aim 1 will delineate the mechanism by which inflammation reduces angiogenesis via downregulating Dnmt3b during fracture repair. Specific Aim 2 will determine the optimal release kinetics of OPN and CXCL12 on angiogenesis. Specific Aim 3 will determine the therapeutic effect of sustained OPN and CXCL12 release on angiogenesis and fracture nonunion in mice. The proposed studies will enhance our understanding of mechanisms by which systemic inflammation (via the NF- κB pathway) affects the angiogenic process through Dnmt3b. This work will establish an important therapeutic option to improve the angiogenesis and fracture healing.

抽象的在美国，大约 160 万块骨头的骨折不愈合是一个严重的临床问题。骨折每年都会遇到长时间愈合或不愈合的情况骨折不愈合治疗通常涉及。实践中手术复杂、规模大，有时需要多次手术，因此增加医疗保健费用并导致患者明显残疾。并发症是患有炎症的患者，例如老年患者、吸烟、糖尿病或类风湿患者关节炎（RA）患者，强调慢性全身炎症对骨折的潜在有害作用维修。该提案的总体假设是慢性炎症导致骨折不愈合通过 Dnmt3b 下调介导的血管生成缺陷，以及 OPN 和 CXCL12 的局部递送恢复炎症条件下的血管生成和骨折修复这一假设得到了我们的初步支持。因此，我们的数据表明，Dnmt3b 在骨折修复过程中在骨折愈伤组织中高表达，并且 Dnmt3b 我们提供了与我们的提案相关的对 MPC 中细胞因子有反应的主要 DNA 甲基转移酶 (Dnmt)。有证据表明，炎症信号以 NF-κB 依赖性方式抑制 Dnmt3b。软骨细胞中的 Dnmt3b 功能丧失 (LOF) 显示血管生成和骨折修复受损；软骨细胞的功能获得（GOF）在体外显示出对炎症的保护作用并加速小鼠骨折修复，炎症和 Dnmt3b LOF 介导的血管生成缺陷。与 OPN（骨桥蛋白）和 CXCL12（C-X-C 基序趋化因子配体 12）的下调同时发生外源性OPN和CXCL12能否在体外恢复血管生成能力，进一步检验局部的疗效。为了在体内传递 OPN 和 CXCL12，我们开发了一种优化的生物材料片，负载有 OPN 和 CXCL12 CXCL12 并在 RA 小鼠中显示出强大的血管生成过程和骨折愈合的恢复。提出了三个主要具体目标，具体目标 1 将描述其机制。炎症通过在骨折修复过程中下调 Dnmt3b 来减少血管生成。确定 OPN 和 CXCL12 对血管生成的最佳释放动力学。具体目标 3 将确定持续释放 OPN 和 CXCL12 对小鼠血管生成和骨折不愈合的治疗作用。拟议的研究将增强我们对全身炎症（通过 NF- κB 通路）通过 Dnmt3b 影响血管生成过程，这项工作将建立一种重要的治疗方法。改善血管生成和骨折愈合的选择。