Preventive and Therapeutic Effects of Bone Marrow Stem Cell-Derived Exosomes on Spine Dural Fibrosis

项目摘要/摘要 背部手术失败综合征(FBSS)是指背部手术后脊髓和神经根出现的一系列症状 脊柱手术，特别是椎板切除术和椎间盘切除术，高达40%的患者经历过慢性 神经根性疼痛和下肢无力。其主要原因是硬脑膜受压和硬脑膜压迫 脊髓硬膜外纤维化所致的神经根，包括硬膜外纤维化和硬膜外粘连。多因素主导 硬脑膜纤维化是手术创伤后的炎症反应和过度的基质沉积。 激活的肌成纤维细胞。硬脊膜纤维化，如果保守治疗不当，一般可以 病情恶化，可能需要手术治疗。然而，这些手术干预的成功率只有30%-35%， 高达20%的患者病情更严重。因此，迫切需要防止和 治疗硬脊膜纤维化。外切体由于其作为硬脑膜抑制剂的巨大潜力而引起了人们的注意。 纤维化症。受损的组织是通过外体的旁分泌信号修复的，而不是直接增殖 和分化，这种旁分泌效应暗示外体治疗比干细胞具有临床优势。 移植在免疫反应和肿瘤发生方面的作用。间充质干细胞(MSCs)是 前景看好的外切体来源，以及MSC衍生的外切体显示出明显的减轻肝纤维化 还有肺。 长期目标是开发一种治疗脊柱硬膜纤维化的微创抗纤维化疗法。要实现 为了达到这一目标，我们建议评估外切体对α-平滑肌肌动蛋白(α-SMA)还原的影响。 人肌成纤维细胞的I型胶原和收缩活性及其体内预防作用 椎板切除模型。我们的中心假设是：外切体具有减轻肌成纤维细胞的潜力 活性，水凝胶将允许外切体的持续释放，并限制成纤维细胞的物理迁移 硬脑膜和后方组织之间的屏障。这些假设是基于我们的假设而设计的 初步数据显示，骨髓间充质干细胞衍生的外切体具有预防和治疗潜力 转化生长因子-β1(转化生长因子-β-1)诱导的牛肌成纤维细胞。减少了 α-β-SMA作为肌成纤维细胞的标志物，在外切体治疗前后的表达显著。 在拟议的R21项目完成后，我们的预期结果是确定治疗潜力 外切体预防硬膜外纤维化和鉴定可能调节抗纤维化的microRNAs(MiRNA) 效果。这些结果将为我们未来的R01提供初步数据，从而产生非常重要的积极影响 GRANT应用，这将是在体内评估MSC来源的外切体在治疗后的疗效 诱导硬脑膜纤维化并合成靶向miRNAs以避免干细胞培养作为外体的一种手段 制作。人工合成的miRNAs将被装载到工程外体中，用于体内传递，从而取代MSC 培养作为一种潜在的外显体生产手段。

PROJECT SUMMARY/ABSTRACT Failed back surgery syndrome (FBSS) refers to a cluster of symptoms in spinal cord and nerve roots after spinal surgery, especially laminectomy and discectomy, and up to 40% of patients have experienced chronic nerve radicular pain and lower extremity weakness. The main cause of FBSS is the compression of dura and nerve roots due to spinal dural fibrosis, including epidural fibrosis and peridural adhesion. Multiple factors leading to dural fibrosis are the inflammatory response post-surgical trauma and excessive matrix deposition by highly activated myofibroblasts. Spinal dural fibrosis, if not properly treated by conservative management, can generally worsen, which may require surgical treatments. However, success of these surgical interventions is only 30-35%, and up to 20% of patients have more serious condition. Thus, there is a critical and urgent need to prevent and treat spinal dural fibrosis. Exosomes have attracted attention due to their great potential as an inhibitor of dural fibrosis. Damaged tissues are repaired by the paracrine signaling of exosomes rather than direct proliferation and differentiation and this paracrine effect implies that exosome therapy has a clinical advantage over stem cell transplantation in terms of immune response and tumorigenesis. Mesenchymal stromal/stem cells (MSCs) are promising sources of exosomes, and MSC-derived exosomes showed an evident reduction of fibrosis in liver and lung. The long-term goal is to develop a minimally invasive anti-fibrosis therapy for spine dural fibrosis. To achieve that goal, we propose to evaluate the effects of exosomes on reduction of alpha smooth muscle actin (α-SMA), type I collagen, and contractile activities in human myofibroblasts and the in vivo preventive effects in a rat laminectomy model. Our central hypotheses are that: exosomes have the potential to alleviate myofibroblast activities, and hydrogel will allow sustained release of exosomes and restrict fibroblast migration as a physical barrier between the dura mater and posterior tissue. The hypotheses have been devised on the basis of our preliminary data, which revealed that MSC-derived exosomes showed both preventive and therapeutic potential in exogenously induced bovine myofibroblasts by transforming growth factor beta 1 (TGF-β1). The reduction of α-SMA expression as a myofibroblast marker was notable in pre- and post-TGF-β1 treatment with exosomes. At the completion of the proposed R21 project, our expected outcomes are to define the therapeutic potential of exosomes for prevention of peridural fibrosis and to identify microRNAs (miRNA) that may regulate anti-fibrotic effects. These results will have a very important positive impact by providing preliminary data for our future R01 grant application, which will be to evaluate in vivo therapeutic effects of MSC-derived exosomes treated after induction of dural fibrosis and to synthesize target miRNAs to avoid stem cell culture as a means of exosome production. Synthetic miRNAs will be loaded in engineered exosomes for in vivo delivery, thereby replacing MSC culture as a potential means of exosome production.