Tendon TRAP: Targeted Therapeutic Delivery to Enhance Tendon Healing

项目摘要 损伤后，肌腱通过纤维性疤痕组织反应愈合，阻碍完全功能恢复。 促进肌腱愈合的药物疗法的转化受到了有限的 系统治疗的肌腱靶向性，以及对生物知情治疗的识别不足 目标。在这项高风险、高回报的研究中，我们将解决这两个关键的知识差距。我们有 最近发现S100a4的基因敲除是一种新的功能增强肌腱愈合模型， 从而确定S100a4为促进肌腱愈合的新的治疗靶点。此外，我们还使用了 空间转录图谱确定决定纤维性肌腱的空间不同的分子过程 治愈的过程。使用这种方法，我们定义了一个富含巨噬细胞的星团，位于 损伤部位的反应性肌腱残留物。这一簇是由Acp5基因的丰富表达定义的 编码抗酒石酸酸性磷酸酶(TRAP)。我们的初步数据进一步证明了 愈合中的肌腱有很强的陷阱活性。在这里，我们将利用这一令人兴奋的发现，利用我们的 使用陷阱结合多肽(TBP)结合纳米粒(NP)给药系统。我们有 显示TBP-NPs在包括骨骼在内的高TRAP活性部位的定位和保持能力增强 骨折骨痂和病理性骨重建过程中。在这里，我们将检验陷阱的中心假设 结合多肽纳米粒(TBP-NPs)有效地定位于愈合肌腱，被 巨噬细胞和TBP-NP释放S100a4抑制剂可促进肌腱再生 控制TBP-NPs。在目标1中，我们将跟踪系统性和肌腱特异性的定位和保留 系统注射荧光标记的TBP-NPs与混杂的对照多肽-NPs的比较。在……里面 此外，我们将使用细胞型特定荧光报告鼠模型的组合来定义 在肌腱愈合过程中摄取TBP-NPs的特定细胞群。在目标2中，我们将定义加载和 S100a4抑制剂在TBP-NPs上的释放情况与TBP-NP给药效果的比较 释放药物和控制NPs，抑制S100a4的表达，促进肌腱愈合过程。 这些研究的成功完成将建立一种新型的纳米颗粒介体递送系统，以靶向 高效、高效地愈合肌腱，从而大大提高了 在药理上促进肌腱愈合。

Project Summary Following injury, tendons heal via a fibrotic scar-tissue response that impedes full functional restoration. Translation of pharmacotherapies to enhance tendon healing has been hampered by a combination of limited tendon targeting of systemic treatments, and insufficient identification of biologically informed therapeutic targets. In this high-risk high-reward study we will address both of these critical knowledge gaps. We have recently identified genetic knockdown of S100a4 as a novel model of functionally-enhanced tendon healing, thereby identifying S100a4 as a novel therapeutic target to improve tendon healing. Moreover, we have used spatial transcriptomic profiling to define the spatially distinct molecular processes that dictate the fibrotic tendon healing process. Using this approach we defined a macrophage-rich cluster located between the highly reactive tendon stubs at the injury site. This cluster was defined by enriched expression of Acp5, the gene encoding for TRAP (Tartrate resistant acid phosphatase). Our preliminary data further demonstrate regions of robust TRAP activity in the healing tendon. Here, we will capitalize on this exciting finding by leveraging our work using a TRAP binding peptide (TBP) conjugated nanoparticle (NP) drug delivery system. We have demonstrated enhanced homing and retention of TBP-NPs at sites of high TRAP activity including the bone fracture callus and during pathologic bone remodeling. Here, we will test the central hypothesis that TRAP binding peptide loaded nanoparticles (TBP-NPs) efficiently home to the healing tendon, are taken up by macrophages and that TBP-NP delivery of an S100a4 inhibitor enhances tendon regeneration compared to control TBP-NPs. In Aim 1 we will track the systemic and tendon-specific localization and retention of systemically administered fluorescently labelled TBP-NPs compared to scrambled control peptide-NPs. In addition, we will use a combination of cell-type specific fluorescent reporter mouse models to define the specific cell populations that uptake TBP-NPs during tendon healing. In Aim 2 we will define the loading and release profile of an S100a4 inhibitor on TBP-NPs and define the efficacy of TBP-NP drug delivery, compared to free drug and control NPs, to inhibit S100a4 expression and enhance the tendon healing process. Successful completion of these studies will establish a novel nanoparticle-mediate delivery system to target the healing tendon with high efficiency and efficacy, thereby substantially enhancing the translational feasibility of pharmacologically mediating improved tendon healing.