Innate immune regulation of stem cells in bone formation

干细胞在骨形成中的先天免疫调节

基本信息

批准号：
9134038
负责人：
EDWARD C HSIAO
金额：
$ 34.87万
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：
2015
资助国家：
美国
起止时间：
2015-09-01 至 2020-08-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9134038
关键词：
ACVR1 gene Acute Adopted Adult Affect Allografting Blast Cell Bone Morphogenetic Proteins Bone Regeneration Breathing Bypass CXCL12 gene Cell Count Cell Culture Techniques Cell Line Cells Child Chondrogenesis Chronic Cues Deposition Disease Endothelial Cells Flare Fracture Future Graft Survival Growth Health Hereditary Disease Heterotopic Ossification Homeostasis Hormones Human Immune Immune response Immune system Immunologics In Vitro Inflammation Inflammatory Injury Interleukin-12 Knowledge Lead Learning Lesion Link Macrophage Activation Mediating Mediator of activation protein Mesenchymal Stem Cells Minerals Modeling Mus Musculoskeletal Diseases Mutation Myelogenous Myeloid Cells Natural Immunity Neurologic Operative Surgical Procedures Osteogenesis Osteoporosis Pathway interactions Patients Production Property Public Health Publishing Recruitment Activity Regulation Reporter Role Serum Signal Pathway Site Skeleton Stem cells Stimulus System Techniques Testing Tissue Engineering Tissue Grafts Trauma bone bone loss cell type chemokine cytokine disability human disease improved in vivo induced pluripotent stem cell macrophage osteogenic osteoprogenitor cell pathogen prevent progenitor progressive myositis ossificans receptor sensitivity repaired research study response response to injury skeletal skeletal disorder tool

项目摘要

DESCRIPTION (provided by applicant): Musculoskeletal diseases including fractures and osteoporosis are the second-greatest cause of disability worldwide. Unfortunately, our ability to treat or repair damaged bone is extremely limited. This contrasts sharply with human diseases of heterotopic ossification which clearly show that adult humans can form large amounts of bone, particularly after acute trauma. The innate immune system is a key mediator of injury responses and has critical functions in regulating fracture repair and anabolic responses to hormones. Innate immune cells such as macrophages are also important for the formation of heterotopic bone. In this proposal we use a genetic disease of heterotopic ossification, fibrodysplasia ossificans progressiva (FOP), as a model to understand how the immune system affects post-natal bone formation. FOP is characterized by massive heterotopic ossification that can occur after injury. FOP is caused by a mutation in ACVR1 which increases receptor sensitivity to bone morphogenetic proteins (BMPs), but the mechanisms that link injury to ossification are unclear. Our central hypothesis is that activation of the innate immune system can enhance the recruitment and differentiation of skeletal precursors in FOP. We previously created human induced pluripotent stem cells (iPS cells) from patients with FOP. These iPS cells showed increased chondrogenesis and mineral deposition. Our cultures also showed increased numbers of endothelial cells (ECs), which can adopt MSC-like properties when transfected with the FOP ACVR1 mutation. We also found that FOP iPS cell-derived endothelial cell progenitors (iECPs) expressed high levels of OSTERIX, RUNX2, and SOX9, three master regulators of bone formation. We will pursue three aims to determine how the innate immune system is affected by ACVR1 activity in FOP. In Aim 1, we will create a new set of iPS cell lines marked with an OSX/SP7-mCherry reporter to detect osteoprogenitors. We will then test if FOP iECPs exposed to inflammatory cues form more osteogenic precursors than control lines. In Aim 2, we will test if FOP iECP cells are chemotactic to candidate cytokines we identified in our preliminary experiments, and if FOP iPS cell derived macrophages to respond abnormally to activation triggers. Finally, in Aim 3, we will test if macrophage-specific activation of ACVR1 by the Q207D mutation is sufficient to initiate heterotopic ossification after injury in vivo. Togethe, our studies use newly-developed techniques to understand how the BMP signaling pathway activated by ACVR1 leads to heterotopic ossification. The tools and findings are directly applicable to FOP and can also be used to study diseases in and out of the skeleton. Finally, understanding how the immune system can enhance skeletal growth will be useful for treating diseases of bone loss, preventing abnormal bone gain, and improving allograft survival and function.

描述（由适用提供）：包括骨折和骨质疏松症在内的肌肉骨骼疾病是全球残疾的第二大原因。不幸的是，我们治疗或修复受损骨骼的能力极为有限。这与异位骨化的人类疾病形成鲜明对比，这清楚地表明，成年人可以形成大量骨骼，尤其是在急性创伤之后。先天免疫系统是损伤反应的关键介体，在确定裂缝修复和对激素的合成代谢反应方面具有关键功能。先天免疫核管（例如巨噬细胞）对于形成异位骨也很重要。在此提案中，我们使用异位骨化遗传疾病，纤维肿瘤的骨化剂渗透症（FOP）作为一种模型，以了解免疫系统如何影响产后骨的形成。 FOP的特征是受伤后可能发生的大量异位骨化。 FOP是由ACVR1突变引起的，该突变增加了受体对骨形态发生蛋白（BMP）的敏感性，但是将损伤与骨化联系起来的机制尚不清楚。我们的中心假设是，先天免疫系统的激活可以增强FOP中骨骼前体的募集和分化。我们以前从FOP患者中创建了人类诱导的多能干细胞（IPS细胞）。这些IPS细胞显示软骨发生和矿物质沉积增加。我们的培养物还显示出增加的内皮细胞数量（EC），当用FOP ACVR1突变翻译时，可以采用类似MSC的特性。我们还发现，FOP IPS细胞衍生的内皮细胞祖细胞（IECP）表示高水平的Osterix，Runx2和Sox9，这是骨形成的三个主调节剂。我们将追求三个目标，以确定先天免疫系统如何受FOP中ACVR1活性的影响。在AIM 1中，我们将创建一组带有OSX/SP7-MCHERRY记者标记的IPS细胞系，以检测骨化剂。然后，我们将测试FOP IECP是否暴露于炎症提示中，比对照线更大的成骨前体。在AIM 2中，我们将测试FOP IECP细胞是否对我们在初步实验中鉴定的候选细胞因子进行趋化，以及是否使用FOP IPS细胞衍生的巨噬细胞，我们的研究使用新开发的技术来了解ACVR1激活的BMP信号通路如何导致ACVR1导致异型质量化。最后，在AIM 3中，我们将测试Q207D突变对ACVR1的巨噬细胞特异性激活足以在体内损伤后启动异位骨化。 Togeth，我们的研究使用新开发的技术来了解ACVR1激活的BMP信号通路如何导致异位骨化。这些工具和发现直接适用于FOP，也可用于研究骨骼内外疾病。最后，了解免疫系统如何增强骨骼生长将有助于治疗骨质流失，防止异常的骨骼增益以及改善同种氏菌生存和功能。