Role(s) of VEGF in Resolution of Inflammation

描述(申请人提供)：炎症是正常伤口修复的关键过程。在创伤后，细胞因子被激活，并将包括巨噬细胞在内的白细胞吸引到伤口部位。巨噬细胞是肉芽组织正确形成的关键，因为它们清理伤口中的死亡细胞，并产生过量的细胞因子，启动愈合组织的形成。虽然许多早期参与炎症的详细机制已为人所知，但那些参与炎症消退的机制却知之甚少。了解炎症是如何结束的与了解其开始一样重要，因为炎症的延长会导致愈合受损和慢性炎症状况。血管内皮生长因子是伤口愈合的关键因素，主要因其在血管生成中的作用而为人所知。然而，最近，血管内皮生长因子作为一种免疫和炎症的调节剂出现了。我们发现，在创伤愈合过程中，血管内皮生长因子有助于化解巨噬细胞诱导的炎症反应，并在培养中刺激巨噬细胞的凋亡。我们还发现，血管内皮生长因子能刺激人巨噬细胞表达TNFSF14/LIGHT。LIGH是已知的调节T细胞共刺激和粘膜肿瘤细胞凋亡的细胞因子超家族中的一员。我们的发现指出了一种新的细胞因子调节的途径，参与了炎症反应的解决。在这里提出的工作中，我们讨论了这些新发现的血管内皮生长因子在伤口愈合过程中消退炎症的功能的后果。我们假设，血管内皮生长因子在愈合过程中的一个新功能是调节受损组织中巨噬细胞的存活，而光是这一过程的关键介质。具体地说，我们将：(1)确定血管内皮生长因子是否在体内诱导巨噬细胞凋亡并刺激愈合过程中LIGH的表达；(2)确定VEGF诱导的巨噬细胞死亡与LIGH的关系。我们将使用培养的人类巨噬细胞、正常小鼠和转基因小鼠的组合，再加上血管内皮生长因子激动剂/拮抗剂和光依赖通路。将使用组织化学和免疫学技术、酶联免疫吸附试验、多重RT-PCR和siRNA技术。提出的工作是新颖的，因为它揭示了以前未知的血管内皮生长因子的功能，它很重要，因为它可能促进新的治疗方法的开发，用于愈合不良的伤口以及其他以过度炎症为特征的疾病和血管内皮生长因子上调的肿瘤。由于在大多数不正常的愈合情况下，炎症很难或根本没有消退，因此这项研究对健康具有重要意义，因为它确定了一种改善受损愈合的新策略，这是一个关键的医学领域。公共卫生相关性：炎症是正常伤口修复的关键过程。在创伤后，细胞因子被激活，并将包括巨噬细胞在内的白细胞吸引到伤口部位。巨噬细胞是肉芽组织正确形成的关键，因为它们清理伤口中的死亡细胞，并产生过量的细胞因子，启动愈合组织的形成。了解炎症是如何结束的与了解其开始一样重要，因为炎症的延长会导致愈合受损和慢性炎症状况。我们发现，在伤口愈合过程中，血管内皮生长因子有助于化解巨噬细胞引起的炎症，并刺激巨噬细胞死亡。这里提出的研究是为了测试血管内皮生长因子在炎症消退中发挥作用的可能性，以及光是否介导血管内皮生长因子在炎症消退中的作用。由于在大多数不正常的愈合情况下，炎症的消退很少或根本不发生，这一系列研究对健康具有重要意义，因为它确定了一种潜在的新策略，用于改善受损的愈合，这是一个关键的医学领域。

DESCRIPTION (provided by applicant): Inflammation is a key process in normal wound repair. Upon wounding, cytokines are activated and chemoattract leukocytes, including macrophages, to the wound site. Macrophages are key for the proper formation of granulation tissue because they clean up dead cells in the wound and produce a plethora of cytokines that initiate formation of the healing tissue. While many detailed mechanisms involved early in inflammation are known, those involved in resolution of inflammation are poorly understood. Understanding how inflammation ends is as important as understanding its beginning because prolongation of inflammation leads to impaired healing and chronic inflammatory conditions. VEGF is a key factor in wound healing and is primarily known for its role in angiogenesis. However, recently VEGF is emerging as a regulator of immunity and inflammation. We have discovered that VEGF contributes to resolution of macrophage- induced inflammation during wound healing and that it stimulates macrophage apoptosis in culture. We have also shown that VEGF stimulates the expression of TNFSF14/LIGHT in human macrophages. LIGHT is a member of the TNF superfamily of cytokines known to regulate co-stimulation of T cells as well as apoptosis in mucosal tumors. Our findings point to a novel cytokine-modulated pathway involved in resolution of the inflammatory response. In the work proposed here we address the consequences of these newly discovered functions of VEGF in resolution of inflammation during wound healing. We hypothesize that a novel function of VEGF in the healing process is modulation of macrophage survival in the damaged tissue and that LIGHT is a critical mediator of this process. Specifically, we will: (1) Determine whether VEGF induces macrophage apoptosis in vivo and stimulates LIGHT expression during healing and (2) Determine the relationship between VEGF-induced macrophage cell death and LIGHT. We will use a combination of cultured human macrophages, normal and genetically-modified mice, coupled with agonists/antagonists of VEGF- and LIGHT-dependant pathways. Histochemical and immunological techniques, ELISA, multiplex RT-PCR and siRNA technology will be used. The work proposed is novel because it reveals previously unknown functions of VEGF and it is important because it may facilitate the development of new therapies for poorly-healing wounds as well as other conditions characterized by excessive inflammation and for tumors in which VEGF is upregulated. Because resolution of inflammation occurs poorly or not at all in most abnormal healing situations, this line of investigation is significant for health because it identifies a novel strategy for improving impaired healing, a critical medical area. PUBLIC HEALTH RELEVANCE: Inflammation is a key process in normal wound repair. Upon wounding, cytokines are activated and chemoattract leukocytes, including macrophages, to the wound site. Macrophages are key for the proper formation of granulation tissue because they clean up dead cells in the wound and produce a plethora of cytokines that initiate formation of the healing tissue. Understanding how inflammation ends is as important as understanding its beginning because prolongation of inflammation leads to impaired healing and chronic inflammatory conditions. We have discovered that VEGF contributes to resolution of macrophage-induced inflammation during wound healing and that it stimulates macrophage death. The studies proposed here are to test the possibility that VEGF is a player in resolution of inflammation and that LIGHT mediates the VEGF effects on resolution of inflammation. Because resolution of inflammation occurs poorly or not at all in most abnormal healing situations, this line of investigation is significant for heath because it identifies a potentially novel strategy for improving impaired healing, a critical medical area.