Pericyte mobilisation and functional plasticity in chronic allergic airway disease

这里描述的研究项目最终旨在回答与肺血管相关的结构细胞(周细胞)的生物学以及这些细胞如何参与过敏性哮喘的发病机制的基本问题。具体地说，这项研究建议旨在调查慢性过敏性炎症调节过敏性哮喘小鼠模型中周细胞功能可塑性和动员的假设。主要目标是确定周细胞动员在过敏性哮喘中的机制和功能后果，并评估这些细胞在健康和患病肺中的干细胞能力。这些实验的结果不仅增加了我们对肺居留结构细胞在哮喘病理中的作用的了解，还将为我们深入了解过敏性哮喘的一个以前未被探索的治疗靶点。目的1我的初步实验证明，周细胞从与大气道相关的血管中分离，并向呼吸道的基底膜迁移，在那里它们结合到气道壁的平滑肌肉中。在本项目中采用的屋尘螨驱动的哮喘模型中，气道平滑肌增厚的发展与气道阻力的显著增加是暂时一致的。事实上，一些临床研究已经证明，气道平滑肌增厚和气道高反应性(喘息)之间存在关联。然而，导致气道平滑肌增厚的机制尚不完全清楚。该项目的这一部分旨在确定负责将周细胞招募到气道壁的趋化机制，从而为深入了解它们在气道重塑中的作用提供机制。目的2已发现周细胞具有祖细胞/干细胞能力，类似于骨髓间充质干细胞的特征。这支持这样一种观点，即尽管周细胞可能促进疾病进展中的病理事件(即呼吸道重塑)，但它们也可能具有免疫调节能力，就像来自身体其他部位的间充质干细胞所显示的那样。在这个项目的第二部分，我计划使用我在白细胞生物学小组的导师Sara Rankin教授的实验室已经建立的技术，从健康和哮喘小鼠的肺中分离周细胞，并评估它们的干细胞标记物的表达，它们分化为各种间充质细胞系(脂肪细胞、软骨细胞、成骨细胞和平滑肌细胞)的能力，以及它们调节过敏原特异性免疫反应的能力。该项目的结果不仅将为一种肺间充质干细胞的身份和特征提供信息，还将为这些细胞调节炎症反应的能力提供有价值的知识。本项目的这一部分旨在研究改变周细胞的行为作为过敏性哮喘治疗干预的可行性。这将通过使用腺病毒载体来实现，这两种载体都是商业获得的，由我的合作者卡罗林斯卡研究所的乌尔夫·埃里克森教授提供。根据这项研究的前两个部分的结果，周细胞的基因表达将在体外和体内进行修饰，目的要么是抑制它们从血管中动员并整合到平滑肌中，要么是增强它们的免疫调节能力，从而作为哮喘呼吸系统中发生的有害结构变化的负面调节因子。

The research project described here ultimately aims to answer fundamental questions on the biology of structural cells (pericytes) associated with the blood vessels in the lung and how these cells contribute to the pathogenesis of allergic asthma. Specifically, this research proposal aims to investigate the hypothesis that chronic allergic inflammation modulates pericyte functional plasticity and mobilisation in a mouse model of allergic asthma. The primary goal is to identify the mechanisms and functional consequences of pericyte mobilisation in allergic asthma, and also to assess the stem cell capacity of these cells in the healthy and diseased lung. The results from these experiments will not only increase our understanding of the role of lung-resident structural cells in asthma pathology, but will also provide insight into a previously unexplored therapeutic target in allergic asthma.Aim 1My preliminary experiments have demonstrated that pericytes detach from the blood vessels associated with the large airways and migrate toward the basement membrane of the airway, where they incorporate into the smooth muscle of the airway wall. In the house dust mite-driven model of asthma employed in this project, the development of airway smooth muscle thickening coincides temporally with a significant increase in airway resistance. In fact, an association between airway smooth muscle thickening and airway hyperreactivity (wheezing) has been demonstrated in a number of clinical studies. However, the mechanisms that cause airway smooth muscle thickening are incompletely understood. This part of the project is designed to determine the chemotactic mechanisms responsible for recruiting pericytes to the airway wall, thus providing mechanisms insight into their role in airway remodelling. Aim 2Pericytes have been shownfound to possess progenitor/stem cell capacity, similar to the features of bone-marrow derived mesenchymal stem cells. This supports the idea that although pericytes may promote pathological events in disease progression (i.e. airway remodelling), they may also possess immunomodulatory capacity as has been shown for mesenchymal stem cells derived from other parts of the body. In the second part of this project, I plan to use techniques already established in the lab of Prof Sara Rankin, my mentor in the Leukocyte Biology group, to isolate pericytes from the lungs of healthy and asthmatic mice and to evaluate their expression of stem cell markers, their capacity to differentiate into various mesenchymal cell lineages (adipocytes, chondrocytes, osteoblasts and smooth muscle cells) and finally their ability to modulate allergen-specific immune responses. The results from this project will not only inform on the identity and characteristics of a type of lung-resident mesenchymal stem cells, but will also provide valuable knowledge on the capacity of these cells to modulate an inflammatory response.Aim 3TThis part of the project aims to investigate the feasibility ofmodifying the behavior of pericytes as a therapeutic intervention in allergic asthma. This will be achieved by employing adenovirus vectors, both obtained commercially and provided by my collaborator, Prof Ulf Eriksson at the Karolinska Institute. Informed by the results of the first two parts of this study, the gene expression of pericytes will be modified both in vitro and in vivo with the goal of either inhibiting their mobilisation from the blood vessels and incorporation into smooth muscle, or to enhance their immunomodulatory capacity and thereby serve as a negative regulator of the detrimental structural changes that occur in the asthmatic respiratory system.