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Function of Fibro-Adipogenic Progenitors in Heterotopic Ossification of Skeletal Muscle

纤维脂肪祖细胞在骨骼肌异位骨化中的功能

基本信息

批准号：
9366782
负责人：
DAVID J GOLDHAMER
金额：
$ 34.4万
依托单位：
UNIVERSITY OF CONNECTICUT STORRS
依托单位国家：
美国
项目类别：
财政年份：
2017
资助国家：
美国
起止时间：
2017-08-01 至 2022-07-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9366782
关键词：
ACVR1 gene Ablation Activins Address Affect Alleles Amino Acids Apoptosis Area BMP2 gene Blocking Antibodies Bone Formation Inhibition Bone Growth Candidate Disease Gene Cartilage Cell Communication Cell Proliferation Cell Therapy Cells Coculture Techniques Development Diphtheria Toxin Disease Dominant Genetic Conditions Enhancers Environment Exhibits Fiber Fibrosis Functional disorder Gene Expression Gene Targeting General Population Genetic Models Genetic Transcription Glycine Goals Health Hereditary Disease Heterotopic Ossification Hypersensitivity Immunofluorescence Immunologic Impairment Individual Infiltration Injection of therapeutic agent Injury Intramuscular Injections Kinetics Lead Life Life Expectancy Mesenchymal Messenger RNA Modeling Molecular Morbidity - disease rate Mus Muscle Muscle satellite cell Muscular Atrophy Natural regeneration Osteogenesis Pathogenesis Pathologic Pathway interactions Patients Physiologic Ossification Physiological Polymerase Population Research Running Serine Signal Transduction Skeletal Muscle Source Specificity Therapeutic Time Traumatic injury Wild Type Mouse activin A alpha Toxin base bone bone morphogenetic protein receptors experimental study genome-wide global run on sequencing muscle regeneration mutant osteogenic prevent progenitor progressive myositis ossificans promoter regenerative response satellite cell soft tissue tibialis anterior muscle transcriptome transcriptome sequencing

项目摘要

Project Summary Heterotopic ossification (HO), the formation of bone in skeletal muscle and associated soft tissues, can result from traumatic injury or disease. The most extreme form of HO is manifested in the rare, autosomal- dominant genetic disorder, Fibrodysplasia ossificans progressiva (FOP), in which HO continues progressively throughout life, resulting in devastating effects on health and life expectancy. We developed a new genetic model of FOP based on conditional expression of the disease-causing BMP receptor, Acvr1(R206H). Using this model, we identified fibro-adipogenic progenitors (FAPs), a multipotent mesenchymal progenitor in muscle tissue, as the disease-causing cell population. Notably, we have shown that intramuscular injection of BMP2 into wild type mice also leads to FAP-derived HO, suggesting mechanistic similarities of HO pathogenesis in FOP patients and the general population. Studies of HO have focused almost entirely on mechanisms of bone growth, yet severe muscle loss can be a significant contributing factor to patient morbidity. The overarching objectives of this research are to 1) understand how FAP programming becomes subverted for pathological bone formation; 2) understand how regeneration is inhibited in skeletal muscle susceptible to HO; 3) determine whether HO of skeletal muscle is entirely dependent on FAPs. By targeting Acvr1R206H expression to FAPs using PdgrfaCreER and Tie2-Cre drivers, Aim 1 will quantify regeneration impairment, and will determine whether muscle stem cell (satellite cell; SC) dysfunction is responsible for regeneration deficits. These studies will quantify SC proliferation and apoptosis after muscle injury and will define the SC mRNA transcriptome. Aim 1 will also determine whether Acvr1(R206H) expression in FAPs disrupts FAP-SC interactions. Aim 2 will use RNA-Seq to define the FAP transcriptome at early, critical, times after injury to identify gene targets of Acvr1(R206H) signaling. Gro-Seq (Genome-wide Run-On) analyses will quantify changes in active gene transcription, will identify candidate genes regulated by promoter-proximal polymerase pausing, and will identify potential enhancer targets of Acvr1(R206H) signaling. Lineage tracing will determine whether the abnormal muscle environment differentially affects the fate of normal and mutant FAPs. In Aim 3, DTA ablation approaches will determine whether FAPs are the sole source of osteogenic cells in muscle, information that is essential for evaluating the possible efficacy of cell-specific therapies. Activin inhibition has recently emerged as a powerful potential therapy for FOP. Aim 4 will use lineage tracing to address how Activin blockade affects proliferation, survival and developmental capacity of FAPs and SCs. RNA-Seq will define the extent to which Activin inhibition “normalizes” FAP and SC transcriptomes. The proposed research will contribute significantly to an understanding of the cells and cellular interactions responsible for HO and associated inhibition of muscle regeneration, and may lead to the development of strategies for cell-based therapies.

项目总结