Targeting Molecular and Cellular Mediators of Inflammation to Prevent Pathologic Cell Differentiation and Heterotopic Ossification

项目总结 由过度异位成骨或创伤诱导的异位骨化引起的病理学 (HO)，在接受髋关节置换、肌肉骨骼手术的患者中，20%的患者存在实质性的康复障碍 创伤、脊髓损伤、截肢和烧伤。HO患者经历慢性疼痛，受限 关节功能和开放性伤口；他们经常接受外科手术切除病变的骨骼，但 这些手术不能逆转关节痉挛和受限的活动范围。即使在一次成功的 切除手术后，复发是常见的。鉴于目前我们对Ho和我们的 无法阻止它的发展，我们开始澄清负责的细胞和主要的信号通路 牵涉其中。此外，我们计划验证一种新的细胞特异性药物传递系统，以阻断a的分泌。 初级细胞(巨噬细胞)的初级配体(骨形态发生蛋白-2)，负责诱导HO。 对HO高危患者和我们的烧伤/肌腱切开术HO模型的分析表明， 缺氧诱导因子1α(HIF-1)和骨形态发生蛋白2(BMP2)信号转导增加。 然而，BMP2配体的来源以及如何在不引起靶外效应的情况下阻断其作用是 未知。此外，我们的数据显示巨噬细胞在HO中发挥核心作用，进一步的研究是 需要澄清它们是如何被招募的，以及它们在运输到受伤地点时分泌哪些配体。 以下目的是验证我们的假设，即抑制间充质细胞缺氧诱导因子-1介导 巨噬细胞募集或抑制巨噬细胞BMP2的表达将阻止创伤诱导的HO。 目的1：证实HIF1a基因缺失可减少间充质细胞分泌SDF1。 损伤后巨噬细胞浸润。这一目的将证明HIF-1α介导的SDF-1通过 损伤部位的间充质细胞负责在损伤后立即招募巨噬细胞。 目的2：明确巨噬细胞募集和巨噬细胞特异性产生骨形态发生蛋白2的作用。 呵呵。这一目的将证明巨噬细胞迁移到损伤部位并产生巨噬细胞。 BMP2在异位间充质细胞软骨形成和异位成骨中起关键作用。 目的3：证明新的微粒可以用来沉默基因 巨噬细胞。这一目标将优化巨噬细胞特异性摄取和药物输送的微粒，以 给予BMP2 siRNA。

PROJECT SUMMARY Pathology stemming from excess ectopic bone formation, or trauma-induced heterotopic ossification (HO), presents a substantial barrier to recovery in 20% of patients with hip replacements, musculoskeletal trauma, spinal cord injury, amputations and burn injuries. Patients with HO experience chronic pain, restricted joint function, and open wounds; they often undergo surgical procedures to excise the offending bone, but these procedures fail to reverse the joint contractures and restricted range of motion. Even after a successful excision procedure, recurrence is common. With these current limitations in our understanding of HO and our inability to prevent its development, we set out to clarify the cells responsible and primary signaling pathways involved. Furthermore, we plan to validate a novel cell specific drug delivery system to block secretion of a primary ligand (Bone Morphogenetic Protein-2) from a primary cell (macrophage) responsible for inducing HO. Analysis of patients at high risk for HO and of our burn/tenotomy HO model have demonstrated an increase in Hypoxia Inducible Factor 1alpha (HIF-1) and Bone Morphogenetic Protein 2 (BMP2) signaling. However, where the BMP2 ligand originates and how to block its effect without causing off-target effects is unknown. Additionally, our data show that macrophages play a central role in HO and further studies are needed to elucidate how they are recruited and what ligands they secrete when they traffic to the injury site. The following aims are to test our hypothesis that that inhibition of mesenchymal cell HIF-1 mediated macrophage recruitment or inhibition of macrophage Bmp2 expression will prevent trauma-induced HO. Aim 1: To demonstrate that genetic loss of Hif1a reduces SDF1 production by mesenchymal cells and macrophage infiltration after injury. This aim will demonstrate that Hif-1α-mediated production of SDF-1 by mesenchymal cells at the injury site is responsible for macrophage recruitment immediately following injury. Aim 2: To define the role of macrophage recruitment and macrophage-specific production of BMP2 on HO. This aim will demonstrate that macrophage migration to the injury site and macrophage production of BMP2 is critical for ectopic mesenchymal cell chondrogenesis and heterotopic ossification. Aim 3: To demonstrate that novel microparticles can be used to silence genes specifically in macrophages. This aim will optimize microparticles for macrophage-specific uptake and drug delivery to administer Bmp2 siRNA.