Molecular and cellular mechanisms of heterotopic ossification

项目摘要/摘要 异位骨化(HO)，骨骼肌和软组织中异位软骨内骨的形成 组织，是关节不能活动和疼痛的一个重要原因。精确的机械装置 HO的责任尚不清楚；然而，它与创伤、炎症和 生物力学应力暗示了一个无序的损伤修复和动态平衡的过程。我们有 探讨HO的单基因致病因素骨化纤维发育不良的潜在机制 由骨形态发生蛋白(BMP)I型激活突变引起的进展性(FOP) ALK2受体，而创伤诱导的HO似乎受ALK2、ALK3和潜在的 ALK6.FOP和获得的HO形式共享不适当的BMP信号的共同机制， 但BMP信号被解释为调节骨化而不是组织的方式 再生仍然没有被完全理解。在BMP/TGFb如何组合方面存在显著差距 信号转导在多能谱系中规定了不同的功能和细胞命运。致信地址 这些机械缺口，一个创新的化学生物平台已经被设计出来，利用人类- 经CRISPR/Cas9技术编辑的衍生MSC，与新的BMP/转化生长因子-b结合 从活跃的NCATS-TRND合作中确定的药理探针。这个平台将允许 单个配体和受体信号的明确映射，以及下游对 在非过表达的人类细胞系统中的MSC可塑性。这个测试提供了一个高水平的平台 与NCATS-TRND的合作者一起进行吞吐量筛查，以机械方式识别 ALK2、ALK3和ALK6的新型调节剂。最后，从以下方面确定的见解和候选分子 这些研究将在FOP的条件敲入小鼠模型中得到验证，并在真实的 创伤和炎症诱导的HO小鼠模型。这些研究将提供关键的工具和 骨形态发生蛋白信号通路在大鼠脑内病理组织重塑中的作用 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、炎症和代谢压力有关。新的检测技术、工具 化合物，并将产生可翻译的见解，作为这项工作的结果，将与 许多其他以疾病为导向的研究领域。

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.