Molecular and cellular mechanisms of heterotopic ossification

项目概要/摘要 异位骨化（HO），即骨骼肌和软组织中异位软骨内骨的形成。 组织，是关节不动和疼痛的发病率的重要原因。精确的机制 负责HO是未知的;然而，它与创伤，炎症和 生物力学应力提示了损伤修复和内稳态紊乱的过程。我们有 探讨了HO的单基因病因骨化性纤维发育不良的潜在机制 进行性（FOP），由骨形态发生蛋白（BMP）I型激活突变引起 受体ALK 2，而创伤诱导的HO似乎受ALK 2，ALK 3调节， ALK 6。FOP和获得性HO形式共享不适当的BMP信号传导的共同机制， 但是BMP信号被解释为调节骨化与组织的方式 再生仍然不完全理解。在BMP/TGF β组合如何 信号转导在多能谱系中指定不同的功能和细胞命运。解决 这些机制的差距，一个创新的化学生物学平台已经设计出使用人类- 已经通过CRISPR/Cas9技术编辑的衍生MSC，与新的BMP/TGF-β结合， 药理学探针从活跃的NCATS-TRND合作中鉴定。该平台将允许 单个配体和受体信号传导的明确映射，以及对 非过表达人类细胞系统中的MSC可塑性。该测定提供了一个平台， 在NCATS-TRND与合作者一起进行通量筛选， ALK 2、ALK 3和ALK 6的新调节剂。最后，我们将从 这些研究将在FOP的条件性基因敲入小鼠模型中得到验证， 创伤和炎症诱导的HO小鼠模型。这些研究将提供关键工具， 深入了解BMP信号通路如何促进病理组织重塑， 肌肉骨骼和退行性疾病，以及在更广泛的条件下，HO是 与衰老、炎症和代谢应激有关。新的分析技术、工具 化合物，和可翻译的见解将产生作为这项工作的结果，这将是相关的， 许多其他疾病导向的研究领域。

PROJECT SUMMARY/ABSTRACT Heterotopic ossification (HO), the formation of ectopic endochondral bone in skeletal muscle and soft tissues, is a significant cause of morbidity from joint immobility and pain. The precise mechanisms responsible for HO are not known; however, its association with trauma, inflammation and biomechanical stress suggests a process of disordered injury repair and homeostasis. We have explored the underlying mechanisms of a monogenic cause of HO, fibrodysplasia ossificans progressiva (FOP), caused by activating mutations of the bone morphogenetic protein (BMP) type I receptor ALK2, whereas trauma-induced HO appears to be regulated by ALK2, ALK3 and potentially ALK6. FOP and acquired forms of HO share a common mechanism of inappropriate BMP signaling, but the manner by which BMP signals are interpreted to regulate ossification versus tissue regeneration remain incompletely understood. Significant gaps exist in how combinatorial BMP/TGFb signal transduction specifies diverse functions and cell fates in multipotent lineages. To address these mechanistic gaps, an innovative chemical biology platform has been devised using human- derived MSC that have been edited by CRISPR/Cas9 techniques, combined with a novel BMP/TGF-b pharmacologic probe identified from an active NCATS-TRND collaboration. This platform will permit the unequivocal mapping of individual ligand and receptor signaling, and the downstream impact on MSC plasticity in a non-overexpressed human cell system. This assay provides a platform for a high throughput screen to be performed with collaborators at NCATS-TRND to identify mechanistically novel modulators of ALK2, ALK3 and ALK6. Finally, insights and candidate molecules identified from these studies will be validated in a conditional knock-in mouse model of FOP, and in an authentic mouse model of trauma- and inflammation-induced HO. These studies will provide critical tools and insights into how the BMP signaling pathway contributes to pathologic tissue remodeling in musculoskeletal and degenerative disease, as well as in a broader set of conditions in which HO is associated with senescence, inflammation, and metabolic stress. New assay technologies, tool compounds, and translatable insights will be produced as a result of this work that will be relevant to many other disease-oriented fields of study.