Effects of lymphangiogenesis stimulation on lung allograft rejection

描述(由申请人提供)：肺移植仍然是唯一被证明可以延长慢性阻塞性肺疾病(COPD)和特发性肺纤维化(IPF)等晚期肺部疾病的存活期和提高生活质量的治疗方法。目前移植后的中位生存期为5.3年。移植物植入后淋巴循环的重要性和功能以及受试者发生急性和/或慢性排斥反应的情况知之甚少。一个关键问题是，移植后淋巴管生成是有益的(例如，促进有效的炎症细胞清除)还是有害的(例如，促进引流淋巴结内的抗原递呈和刺激同种异体免疫反应)。淋巴循环在移植肺存活和功能中的作用尚不清楚。血管内皮生长因子(VEGF)-C 156位突变(VEGF-C C156S)可诱导淋巴管生成，但不能诱导血管生成。我们的初步数据显示，发生急性排斥反应的完全同种异体小鼠肺移植的淋巴管密度降低。重要的是，在建立排斥反应后刺激淋巴管的生成可以改善排斥反应。我们假设，在发生排斥反应后用血管内皮生长因子C C156S治疗受体小鼠将通过增加促炎症前纤维化分子如透明质酸的清除而改善移植物功能。为了检验这些假说的有效性，我们提出了以下具体目标：目的1：检验如下假说：在已建立的排斥反应后诱导淋巴管生成将导致移植物排斥反应迹象的减少和肺功能的改善。我们的工作假设是，VEGF-C C156S将诱导淋巴管生成，并导致改善移植物排斥反应和功能。我们的方法将包括用血管内皮生长因子-C C156S治疗小鼠移植受者，跟踪肺功能(成像和生理参数)，并评估排斥迹象(组织学、蛋白质和RNA分析)。目的2：验证诱导淋巴管生成将导致HA清除增强从而改善同种异体肺移植功能的假设。我们的初步数据显示，在肺排斥反应中，透明质酸沉积增加。我们的工作假设是，淋巴管生成的诱导将导致透明质酸清除的改善，从而改善肺移植的功能。我们的方法将包括在诱导淋巴管生成之前和之后检测移植肺透明质酸含量。此外，我们将阻止透明质酸清除，并通过影像、肺生理学和组织学研究评估移植肺。如果成功，这项研究将为淋巴血管生成对肺组织的影响以及体内淋巴循环在肺排斥反应中所起的作用提供新的见解。此外，它还将为开发治疗肺移植受者急性排斥反应的新策略铺平道路。

DESCRIPTION (provided by applicant): Lung transplantation remains the only therapy proven to prolong survival and improve quality of life in advanced lung diseases such as chronic obstructive pulmonary disease (COPD) and idiopathic pulmonary fibrosis (IPF). The median survival after transplantation is currently 5.3 years. Little is known about the importance and function of the lymphatic circulation after graft has been implanted and subjects develop acute and/or chronic rejection. A key question is whether post-transplantation lymphangiogenesis is beneficial (e.g. by promoting efficient inflammatory cell clearance) or detrimental (e.g. by promoting antigen presentation within draining lymph nodes and stimulating alloimmune responses). The role of the lymphatic circulation in lung allograft survival and function remains unclear. Vascular endothelial growth factor (VEGF)-C mutated at residue 156 (VEGF-C C156S) has been shown to induce lymphangiogenesis and not angiogenesis. Our preliminary data indicate that fully allogeneic murine lung grafts exhibit a decrease in the density of lymphatic vessels with acute rejection. Importantly, stimulating lymphangiogenesis after rejection has been established results in improved rejection. We hypothesize that treatment of recipient mice with VEGF-C C156S after rejection occurs will result in improved graft function by increasing clearance of pro-inflammatory pro-fibrotic molecules such as hyaluronan. To test the validity of these hypotheses, we propose the following specific aims: Aim 1: Will test the hypothesis that inducing lymphangiogenesis after established rejection will lead to decreased signs of graft rejection and improved lung function. Our working hypothesis is that VEGF-C C156S will induce lymphangiogenesis and lead to improved graft rejection and function. Our approach will include treatment of mouse transplant recipients with VEGF-C C156S, followed lung function (imaging and physiological parameters) and assess signs of rejection (histology, protein and RNA analyses). Aim 2: Will test the hypothesis that the induction of lymphangiogenesis will result in enhanced HA clearance that will lead to improved lung allograft function. Our preliminary data show that there is increased hyaluronan deposition in lung rejection. Our working hypothesis is that the induction of lymphangiogenesis will result in improved hyaluronan clearance resulting in improved lung allograft function. Our approach will include examining lung allograft hyaluronan content before and after induction of lymphangiogenesis. In addition, we will block hyaluronan clearance and assess the transplanted lung with imaging, lung physiology and histological studies. If successful, this research will provide new insights into the mechanisms underlying the influence of lymhangiogenesis on lung tissue and the role the lymphatic circulation plays in vivo in lung rejection. In addition, it will pave the way for the development of novel strategies to tret acute rejection in lung transplant recipients.