A new therapeutic approach for fibrodysplasia ossificans progressiva based on ACVR1 over-expression

基于ACVR1过表达的进行性骨化性纤维发育不良的新治疗方法

• 批准号: 9977124
• 负责人: DAVID J GOLDHAMER
• 金额: $ 17.71万
• 依托单位: UNIVERSITY OF CONNECTICUT STORRS
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-07-12 至 2022-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9977124
• 关键词: ACVR1 gene; Activins; Address; Adult; Age; Alleles; Amino Acid Substitution; Arginine; Attention; Attenuated; Behavior; Binding; Bone Morphogenetic Proteins; Cartilage; Cell Transplantation; Cell physiology; Cells; Data; Defect; Development; Dimerization; Direct Lytic Factors; Disease; Disease Progression; Dominant Genetic Conditions; Embryo; Environmental Risk Factor; Equilibrium; Expression Profiling; Fluorescence-Activated Cell Sorting; Functional disorder; Gene Expression; Genes; Genetic; Genetic Diseases; Genetic Models; Genetic Transcription; Genetic study; Genotype; Glycine; Grant; Health; Heterotopic Ossification; Histidine; Histologic; Human; Hypersensitivity; Image; Individual; Injections; Injury; Intrinsic factor; Knock-in Mouse; Lead; Lesion; Life; Life Expectancy; Ligands; Luciferases; Mesenchymal; Messenger RNA; Methods; Minerals; Modality; Modeling; Molecular; Morbidity - disease rate; Mus; Muscle; Muscular Atrophy; Neonatal; Neutralization Tests; Osteogenesis; Outcome; Pathogenicity; Pathologic; Pathway interactions; Patients; Perinatal mortality demographics; Phenotype; Phosphorylation; Physiologic Ossification; Platelet-Derived Growth Factor alpha Receptor; Population; Quality of life; Research; SCID Mice; Serine; Severities; Severity of illness; Signal Transduction; Skeletal Muscle; Skeleton; Specificity; Testing; Therapeutic; Time; Transplantation; Traumatic injury; animal imaging; barium chloride; base; bone; bone morphogenetic protein receptors; computerized tools; effectiveness testing; experimental study; inhibitor/antagonist; injured; insight; interest; mouse model; mutant; novel; novel therapeutic intervention; novel therapeutics; osteogenic; overexpression; procollagen C-endopeptidase; progenitor; progressive myositis ossificans; prospective test; receptor; receptor function; regenerative; response; safety testing; severe injury; skeletal; skeletogenesis; soft tissue; stem cells; stoichiometry; tibialis anterior muscle; transcriptome; transcriptome sequencing; transplant model

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, life expectancy and quality of life. We developed a new genetic mouse 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 of muscle tissue, as the offending cell population that gives rise to the heterotopic skeleton. Our genetic studies indicate that the wild type (WT) ACVR1 receptor functions as a direct or indirect competitive inhibitor of ACVR1(R206H) in heterozygous cells. Based on these findings, the overarching hypothesis that provides the conceptual framework and justification for this exploratory grant posits that WT and mutant ACVR1 compete for limiting osteogenic signaling components and that disease severity is dictated by the stoichiometric balance of these receptors. The primary experimental objective of the current proposal is to determine whether ACVR1 over-expression mitigates the deleterious effects of ACVR1 (R206H) in FOP mice, a result that would provide proof-of-concept for a novel and non-obvious therapeutic approach for FOP. Using a newly developed mouse knockin line that conditionally over-expresses WT human ACVR1 (R26ACVR1), Aim 1 proposes functional studies that utilize quantitative μCT imaging and histological analyses to determine whether ACVR1 over-expression in FAPs effectively inhibits HO. Cell transplantation studies will determine whether ACVR1 over-expression can function cell-non-autonomously, perhaps by binding key osteogenic ligands that drive ACVR1(R206H) signaling. As a sensitive test of the neutralizing effects of ACVR1 receptor over-expression on ACVR1(R206H) function, Aim 1 will also determine whether global embryonic over-expression of ACVR1 can rescue the neonatal-lethal phenotype of mice that broadly express Acvr1R206H. Since severe muscle loss can be a significant contributing factor to patient morbidity, Aim 1 will determine whether ACVR1 over-expression restores muscle regenerative capacity. Aim 2 will use RNA sequencing to define the FAP mRNA transcriptome at early times after injury to identify new direct or indirect transcriptional targets that are associated with entry of multipotent FAPs into the endochondral pathway, and to define the extent to which over-expression of ACVR1 “normalizes” the FAP transcriptome. Finally, transcriptome analysis of both normal and mutant FAPs derived from pathogenic FOP muscle will address the relative extent to which environmental and intrinsic genetic factors dictate FAP cell fates and transcriptional outcomes. The proposed research will contribute significantly to an understanding of molecular mechanisms of pathological FAP reprogramming and may lead to the development of novel therapeutic strategies for FOP based on ACVR1 over-expression.

项目摘要 异位骨化（HO），骨骼肌和相关软组织中的骨形成，可导致 创伤性损伤或疾病。HO的最极端形式表现为罕见的常染色体显性遗传， 遗传性疾病，进行性骨化性纤维发育不良（FOP），其中HO在整个过程中持续进行性 这对健康、预期寿命和生活质量造成了毁灭性影响。我们开发了一种新的基因 基于致病BMP受体ACVR 1（R206 H）的条件表达的FOP小鼠模型。 使用这个模型，我们鉴定了脂肪/脂肪生成祖细胞（FAP），一种多能间充质祖细胞， 肌肉组织，作为引起异位骨骼的有害细胞群。我们的基因研究 表明野生型（WT）ACVR 1受体作为直接或间接竞争性抑制剂发挥作用， 杂合细胞中的ACVR 1（R206 H）。基于这些发现，提供了 这个探索性资助的概念框架和理由假设WT和突变型ACVR 1竞争 限制成骨信号传导成分，疾病的严重程度取决于 这些受体。本提案的主要实验目标是确定ACVR 1是否 过表达减轻了ACVR 1（R206 H）在FOP小鼠中的有害作用，这一结果将提供 FOP的一种新的非显而易见的治疗方法的概念验证。使用一种新开发的老鼠 有条件过表达WT人ACVR 1（R26 ACVR 1）的敲入系，目的1提出功能研究 利用定量μCT成像和组织学分析来确定ACVR 1是否在 FAPs有效抑制HO。细胞移植研究将确定ACVR 1过表达是否可以 可能通过结合驱动ACVR 1（R206 H）信号传导的关键成骨配体来实现细胞非自主功能。 作为ACVR 1受体过表达对ACVR 1（R206 H）功能的中和作用的敏感试验， 目的1还将确定ACVR 1的整体胚胎过表达是否可以挽救胚胎致死性 广泛表达Acvr 1 R206 H的小鼠的表型。由于严重的肌肉损失可能是一个重大贡献 患者发病率的因素，目的1将确定ACVR 1过表达是否恢复肌肉再生 容量目的2将使用RNA测序来确定损伤后早期FAP mRNA转录组， 鉴定新的直接或间接转录靶点，所述靶点与多能FAP进入细胞内相关。 内软骨素途径，并确定ACVR 1的过度表达在多大程度上使FAP“正常化”。 转录组最后，对来源于致病性FOP的正常和突变型FAP的转录组进行分析。 肌肉将解决环境和内在遗传因素决定FAP细胞命运的相对程度 和转录结果。拟议的研究将大大有助于了解 病理性FAP重编程的分子机制，并可能导致新的 基于ACVR 1过表达的FOP治疗策略。