Fate and Regulation of Fracture-induced Prx1 Cells

骨折诱导的 Prx1 细胞的命运和调控

• 批准号: 10436259
• 负责人: Anna Spagnoli
• 金额: $ 33.94万
• 依托单位: RUSH UNIVERSITY MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-03-25 至 2024-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10436259
• 关键词: AMD3100; Achievement; Adult; Affect; Alternative Therapies; Animal Model; Attention; Autologous Transplantation; Automobile Driving; CXC Chemokines; CXCR4 gene; Cell Therapy; Cell Transplantation; Cells; Clinical; Clinical Trials; Complement; Development; Disease; Ensure; Forearm Fracture; Foundations; Fracture; Gene Silencing; Generations; Genes; Genetically Engineered Mouse; Goals; Gold; Hip Fractures; Impairment; In Vitro; Knockout Mice; Knowledge; Lead; Life; Ligands; Limb structure; Molecular; Mus; Natural regeneration; Nature; Operative Surgical Procedures; Patients; Pattern; Pericytes; Persons; Pharmacology; Pharmacology Study; Pharmacotherapy; Phenotype; Population; Process; Regulation; Reporting; Research; Research Personnel; Role; Signal Transduction; Spinal Fractures; Testing; Time; Transplantation; United States; antagonist; base; bone; bone fracture repair; bone morphogenic protein; cardiovascular disorder risk; clinically relevant; clinically significant; conditional knockout; cost; cytokine; design; genetic approach; healing; in vivo; lifetime risk; new therapeutic target; novel; novel therapeutics; osteoprogenitor cell; postnatal; progenitor; public health relevance; receptor; regenerative; repaired; reparative process; skeletal; standard care; stem cells; therapeutic target; transcription factor; transcriptome

PROJECT SUMMARY Fracture healing is a well-orchestrated regenerative process that remains largely unknown. Revealing the cellular and molecular mechanisms governing fracture repair will help identify novel therapeutic targets to treat patients that suffer of non-unions, a clinically relevant problem that affects annually 600,000 people in the United States. Bone autografts, the gold-standard treatment for non-unions, have multiple drawbacks: they are invasive, costly, risky, and sometime ineffective. Therefore, there is an urgent and unmet need for alternative and novel therapies to treat non-unions. The ultimate goal of this proposal is to gain new knowledge on pivotal mechanisms driving fracture repair and to devise them to promote healing. The highly regenerative ability of bones after fracture implies the existence of adult progenitors that contribute to the reparative process. However, the nature and the expression pattern of these progenitors is still elusive. We have discovered a discrete population of perivascular cells expressing Prx1 (Prx1+) that reside in recognized regenerative niches. By investigating functionality, we have found that facture elicits Prx1expression and Prx1+ expressing cells that contribute to the fracture repair process, but cells lose Prx1 expression with differentiation. We have also found that during fracture repair, Prx1+ cells co-express BMP2 and CXCL12. On the way to further explore this crosstalk, we discovered that the impaired fracture healing found in mice lacking a full complement of BMP2 in Prx1 osteochondroprogenitors, was characterized by an abnormally persistent increase of Prx1 and the cytokine CXCL12. These abnormalities were corrected by AMD3100, a CXCL12 receptor antagonist that restored healing. Lastly, by using in vivo and in vitro approaches, we have indicated that BMP2 through CXCL12 signaling regulates Prx1 expression. Current knowledge and these exciting novel observations set the scientific premise to the central hypothesis of this proposal, namely that Prx1 expressing cells are a crossroad in fracture repair and their commitment to regeneration and their Prx1 expression pattern is regulated by a well-timed interplay between BMP2 and CXCL12. Two specific aims are proposed to test this novel hypothesis. Aim 1 is designed to determine the requirement of Prx1 and Prx1 expressing cells and their fate and nature during fracture repair. Aim 2 is designed to determine the mechanisms by which the expression of Prx1 and the fate of Prx1+ cells is regulated by the interplay between BMP2 and CXCL12 during fracture repair. A comprehensive approach will be applied to accomplish the proposed aims, by combining generation of ad hoc genetically engineered mice; cell-tracing; educated use of animal models; pharmacological and cell transplant studies; and in vitro studies. A team of expert research investigators has been assembled to ensure successful achievement of the project. It is expected that the novel findings generated from this research will have major biomedical relevance and implications for: a) understanding the cellular and molecular mechanisms governing fracture healing; and b) laying the groundwork for the development of pharmacological and cell-based clinical trials to treat non-unions.

项目摘要 骨折愈合是一个经过精心修整的再生过程，在很大程度上未知。揭示细胞 和骨折修复的分子机制将有助于确定治疗患者的新型治疗靶标 遭受非工会的困扰，这是一个与临床相关的问题，每年影响美国60万人。 骨自体移植是非工会的金标准处理，具有多种缺点：它们是侵入性的，昂贵的， 冒险，有时无效。因此，对替代和新颖的疗法有紧急且未满足的需求 治疗非工会。该提案的最终目标是获得有关驾驶关键机制的新知识 断裂修复并设计它们以促进康复。骨折后骨骼的高度再生能力 意味着有助于修复过程的成年祖细胞的存在。但是，自然和 这些祖细胞的表达模式仍然难以捉摸。我们发现了离散的周围血管群 表达prx1（PRX1+）的细胞位于公认的再生生态位。通过调查功能，我们 已经发现，构成引起有助于裂缝修复的PRX1表达和PRX1+表达细胞 过程，但是细胞通过分化失去PRX1表达。我们还发现，在断裂修复期间，PRX1+ 细胞共表达BMP2和CXCL12。在进一步探索这个串扰的路上，我们发现 在prx1骨软化剂中缺乏完全补充BMP2的小鼠中发现的骨折愈合受损， 其特征是PRX1和细胞因子CXCL12异常持续增加。这些异常 通过恢复愈合的CXCL12受体拮抗剂AMD3100校正。最后，使用体内和 在体外方法中，我们表明BMP2通过CXCL12信号传导调节PRX1表达。当前的 知识和这些令人兴奋的新颖观察结果为科学前提奠定了核心假设 该建议，即Prx1表达细胞是断裂修复的十字路口及其承诺 再生及其PRX1表达模式受BMP2之间的良好相互作用调节 和CXCL12。提出了两个具体的目的来检验这一新假设。 AIM 1旨在确定 在断裂修复过程中，PRX1和PRX1表达细胞及其命运和性质的需求。 AIM 2是设计的 确定PRX1和PRX1+细胞命运的表达的机制 断裂修复过程中BMP2和CXCL12之间的相互作用。全面的方法将应用于 通过结合临时基因工程小鼠的生成来实现拟议的目标；细胞追踪； 受过动物模型的教育使用；药理和细胞移植研究；和体外研究。一个团队 专家研究调查人员已被组装，以确保成功实现该项目。这是 预计这项研究产生的新发现将具有主要的生物医学相关性和 对：a）了解骨折愈合的细胞和分子机制；和b） 为开发基于药理和细胞的临床试验的基础，以治疗非工会。