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

基本信息

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
项目类别：
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

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, 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.

项目概要异位骨化（HO），即骨骼肌和相关软组织中骨的形成，可导致 HO 最极端的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进展我们开发了一种新的基因，对健康、预期寿命和生活质量造成毁灭性影响。 FOP 小鼠模型基于致病 BMP 受体 ACVR1(R206H) 的条件表达。使用该模型，我们鉴定了纤维/脂肪祖细胞（FAP），这是一种多能间充质祖细胞肌肉组织，作为产生异位骨骼的违规细胞群。表明野生型 (WT) ACVR1 受体可作为直接或间接竞争性抑制剂基于这些发现，杂合细胞中的 ACVR1(R206H) 提供了总体假设。 WT 和突变 ACVR1 竞争的探索性资助职位的概念框架和理由限制成骨信号成分，并且疾病严重程度由化学计量平衡决定当前提案的主要实验目标是确定 ACVR1 是否存在。过度表达可减轻 FOP 小鼠中 ACVR1 (R206H) 的有害影响，这一结果将提供使用新开发的小鼠对一种新颖且非显而易见的 FOP 治疗方法进行概念验证。条件性过度表达 WT 人类 ACVR1 (R26ACVR1) 的敲入线，目标 1 提出功能研究利用定量 μCT 成像和组织学分析来确定 ACVR1 是否在 FAPs 有效抑制 HO 的细胞移植研究将确定 ACVR1 过度表达是否可以。细胞非自主地发挥功能，可能是通过结合驱动 ACVR1(R206H) 信号传导的关键成骨配体。作为 ACVR1 受体过度表达对 ACVR1(R206H) 功能的中和作用的敏感测试，目标 1 还将确定 ACVR1 的整体胚胎过度表达是否可以挽救新生儿致命的疾病。广泛表达 Acvr1R206H 的小鼠的表型，因为严重的肌肉损失可能是一个重要的原因。影响患者发病率的因素，目标 1 将确定 ACVR1 过度表达是否可以恢复肌肉再生目标 2 将在损伤后的早期使用 RNA 测序来定义 FAP mRNA 转录组。识别与多能 FAP 进入相关的新的直接或间接转录靶标软骨内途径，并确定 ACVR1 过度表达使 FAP“正常化”的程度最后，对源自致病性 FOP 的正常和突变 FAP 进行转录组分析。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拟议的研究将有助于显着理解病理性 FAP 重编程的分子机制，并可能导致新的开发基于 ACVR1 过表达的 FOP 治疗策略。