Engineering scarless repair of flexor tendon injuries

屈肌腱损伤的工程无疤修复

• 批准号: 9040516
• 负责人: Hani A Awad
• 金额: $ 38.88万
• 依托单位: UNIVERSITY OF ROCHESTER
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-07-01 至 2020-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9040516
• 关键词: Abate; Address; Adhesions; Affect; Alternative Therapies; Biological Availability; Cell Proliferation; Cells; Cicatrix; Collagen; Complex; Data; Development; Dose; Drug Kinetics; Engineering; Etiology; Extracellular Matrix; Fibroblasts; Fibrosis; Flexor; Funding; Gel; Gene Deletion; Gene Expression; Hand; Hand functions; Healed; Human; Injury; Knock-out; Knockout Mice; Knowledge; Laceration; Lead; Maps; Matrix Metalloproteinases; Mediating; Mediator of activation protein; Metalloproteinase Gene; Methodology; Modeling; Molecular; Molecular Target; Mus; Operative Surgical Procedures; Organ; Peptide Hydrolases; Plasmin; Plasminogen Activator Inhibitor 1; Postoperative Period; Pre-Clinical Model; Prevention; Rehabilitation therapy; Resolution; Role; Signal Transduction; Site; Small Interfering RNA; Source; Structure; System; Tamoxifen; Techniques; Tendon Injuries; Tendon structure; Tensile Strength; Testing; Therapeutic; Tissues; Toxic effect; Transforming Growth Factor beta; Treatment Efficacy; Up-Regulation; Weight-Bearing state; Wild Type Mouse; abstracting; base; cellular targeting; gain of function; healing; human TGFB1 protein; improved; in vitro Model; in vivo; innovation; loss of function; mouse model; nanoparticle; neutralizing antibody; novel; overexpression; regenerative; repaired; response; small molecule; therapeutic target; tissue repair

Abstract. Flexor tendon injuries in zone II of the hand are prone to debilitating adhesions, a form of scar tissue that obstructs gliding of the flexor tendons, severely impairing hand function. There are presently no pharmacologic treatments for the prevention or resolution of tendon adhesions, which still occur in as high as 30% of flexor tendon repairs, despite advances in surgical techniques and post-operative rehabilitation. Therefore, there is an unmet need for a mechanistic understanding of scar etiology in flexor tendons that could lead to the identification of new therapies. In the previous funding period, we established that disruption of canonical TGF-beta signaling in Smad3 knockout mice reduced flexor tendon adhesions but also reduced the tensile strength of the repair tissue. However, the differential effects of TGF-beta on activating peritendinous and intratendinous fibrosis remain unknown, and could be key to identifying novel profibrotic cellular and molecular mechanisms. To address this gap in knowledge, we will first utilize tamoxifen inducible gene deletion mouse models to investigate the effects of loss of canonical TGF-beta signaling in peritendinous versus intratendinous fibroblasts on zone II flexor tendon adhesions (Aim1). Towards the identification of downstream signaling mediators of fibrosis, we demonstrated that TGF-beta upregulates the protease- suppressor, plasminogen activator inhibitor 1 (PAI-1), which inhibits plasmin-mediated MMP activation. Furthermore, we demonstrated that PAI-1 loss of function nullifies TGF-beta1 inhibition of protease (plasmin and MMP) activity, without reducing cell proliferation. Thus, we hypothesize that PAI-1 activity does not affect cell proliferation and flexor tendon healing, but inhibits protease (plasmin and MMP) activity leading to impaired remodeling and increased adhesions. This hypothesis will be tested in Aim 2 by examining flexor tendon healing in mouse models of PAI- 1 loss- and gain-of-function. Collectively, our data suggest that targeting TGF-beta directly might be therapeutically untenable in load-bearing tendons due to its dichotomous effects, which include the indispensible PAI-1-independent effect of activating cell proliferation and matrix synthesis necessary for healing, and the pathogenic effect of inhibiting protease activity via canonical induction of PAI-1. Thus, we hypothesize that localized therapeutic inhibition of PAI-1, irrespective of its cell source, will ameliorate tendon adhesions without adversely affecting repair strength. In Aim 3, we will test this hypothesis by optimizing and investigating the efficacy of an innovative nanoparticle-mediated siRNA delivery system against PAI-1 in zone II flexor tendon injuries in wild type mice. The proposed studies will elucidate the mechanisms by which canonical TGF-beta signaling differentially activates peritendinous fibroblasts leading to extrinsic fibrosis (Aim 1), demonstrate that canonical TGF-beta induction of PAI-1 precipitates fibrotic adhesions (Aim 2), and establish localized, transient nanoparticle-mediated delivery of siRNA to inhibit PAI-1 as a translational, strength-sustaining, anti-adhesion therapy for flexor tendon repair (Aim 3).

抽象的。手的II区屈肌肌腱损伤容易使人衰弱，这是一种疤痕组织的形式 阻塞屈肌肌腱的滑行，严重损害了手部功能。目前没有 预防或分辨肌腱粘连的药理治疗方法，这些治疗仍在 尽管手术技术和术后康复进展，屈肌肌腱维修中有30％。 因此，在屈肌肌腱中对疤痕病因的机械理解的需求未满足 导致鉴定新疗法。在上一个资金期间，我们确定了这种破坏 Smad3敲除小鼠中的典型TGF-β信号传导减少了屈肌粘附，但也降低了 修复组织的拉伸强度。但是，TGF-beta对激活腹膜的差异影响 并且内内内纤维化仍然未知，并且可能是识别新型纤维化细胞和 分子机制。为了解决知识的这一差距，我们将首先利用他莫昔芬诱导基因 删除鼠标模型，以研究脑triendin的规范TGF-beta信号丢失的影响 II区屈肌粘附粘附上的侧底成纤维细胞（AIM1）。识别 纤维化的下游信号传导介质，我们证明了TGF-beta上调蛋白酶 - 抑制剂，纤溶酶原激活剂抑制剂1（PAI-1），抑制纤溶酶介导的MMP激活。 此外，我们证明了PAI-1功能的损失无效TGF-BETA1抑制蛋白酶（纤溶酶 和MMP）活性，而不会减少细胞增殖。因此，我们假设PAI-1活性不会影响 细胞增殖和屈肌肌腱愈合，但抑制蛋白酶（纤溶酶和MMP）活性 重塑和粘附增加受损。该假设将通过检查屈肌在AIM 2中进行检验 PAI-1损失和功能获得的小鼠模型中的肌腱愈合。总体而言，我们的数据表明 直接靶向tgf-beta可能由于其二分法而在承重肌腱上无法治疗 效应，包括激活细胞增殖和基质的不可或缺的PAI-1独立效应 愈合所需的合成以及通过规范诱导抑制蛋白酶活性的致病作用 pai-1。因此，我们假设对PAI-1的局部治疗抑制作用，无论其细胞来源如何 改善肌腱粘附，而不会影响修复强度。在AIM 3中，我们将检验此假设 通过优化和研究创新的纳米粒子介导的siRNA递送系统的功效 在野生型小鼠的II区屈肌肌腱损伤中对抗PAI-1。提出的研究将阐明 规范的TGF-β信号传导差异地激活脑膜成纤维细胞导致的机制 外部纤维化（AIM 1），证明PAI-1的典型TGF-β诱导沉淀 粘连（AIM 2），并建立局部的瞬时纳米颗粒介导的siRNA递送以抑制PAI-1 作为一种屈曲肌腱修复的转化，维持强度的抗粘附疗法（AIM 3）。