Understanding and Controlling Macrophage Behavior in Angiogenesis

项目总结 在血管生成和生物材料血管形成的核心是炎症反应， 主要是巨噬细胞，随着时间的推移，巨噬细胞会对微环境的提示做出反应，从而显著改变表型。 在对损伤的正常反应中，巨噬细胞最初是促炎细胞(又名M1)，在后来的阶段 被统称为M2的混合群体所取代，该群体上调与 解决伤口愈合过程。先前我们发现M1巨噬细胞在启动过程中起着关键作用。 但为了稳定的血管生成和伤口愈合，他们必须改用M2。它的影响范围 这种M2群体的多样性，以及它们如何调控血管生成过程，仍然是未知的。在以后的阶段 血管生成和生物材料血管化，M2巨噬细胞是由M1过渡而来的 巨噬细胞，或2)来自新到的单核细胞的直接分化。M2之间的差异 从每个种群产生的巨噬细胞还没有被研究。初步数据显示，M1派生的 M2巨噬细胞具有增强的血管生成功能，这种生物材料可以瞬时刺激血管生成。 最初的M1阶段可能会增强后续对M2的反应--促进生物材料实现增强 血管形成和愈合。这个项目的首要假设是，促进 同样数量的巨噬细胞依次激活M1和M2将增强血管形成。 我们最近发现，过继转移的巨噬细胞和促进M2的微粒 在促进小鼠后肢缺血模型组织血管重建方面的协同作用。然而， 巨噬细胞迅速从损伤部位清除(在2天内)，这给表型研究带来了困难。 过继转移的巨噬细胞的变化。因此，本项目的目标是通过 巨噬细胞使用生物材料支架作为细胞载体，使巨噬细胞保留在 足够长的时间来跟踪它们的表型变化并观察它们与其他类型细胞的相互作用 参与血管生成。我们将使用多孔支架(而不是水凝胶)，因为我们实验室的其他工作 利用体外研究表明，巨噬细胞-T细胞串扰对于M1型向M2型转变非常重要。 巨噬细胞，所以T细胞能够充盈生物材料载体是很重要的。在目前的项目中，我们 将使用多孔支架将促炎症的M1巨噬细胞注射到损伤部位，以测试 M1巨噬细胞与T细胞串扰促进T细胞Th2分化的假说 巨噬细胞的转化和增强的血管生成。 假设过继转移的M1巨噬细胞将转变为不同的M2 具有增强的血管生成功能的表型(与M0巨噬细胞相比) 内源性T细胞。

Project summary At the heart of angiogenesis and biomaterial vascularization lies the inflammatory response, orchestrated primarily by macrophages, which dramatically shift phenotype over time in response to microenvironmental cues. In the normal response to injury, macrophages are initially pro-inflammatory (aka M1), and at later stages they are replaced by a mixed population referred to collectively as M2 that upregulate factors associated with resolution of the wound healing process. Previously we showed that M1 macrophages are critical for the initiation of angiogenesis, but they must switch to M2 for stable angiogenesis and wound healing. The extent of the diversity of this M2 population, and how they regulate angiogenic processes, is still unknown. At later stages of angiogenesis and biomaterial vascularization, M2 macrophages are generated 1) via transition from M1 macrophages, or 2) from direct differentiation of newly arriving monocytes. The differences between the M2 macrophages arising from each population have not been investigated. Preliminary data suggest that M1-derived M2 macrophages possess enhanced angiogenic functionality, and that biomaterials that transiently stimulate the initial M1 phase may enhance the subsequent response to M2-promoting biomaterials to achieve enhanced vascularization and healing. The overarching hypothesis of this project is that biomaterials that promote sequential M1 and M2 activation of the same population of macrophages will enhance vascularization. We recently found that adoptively transferred macrophages and M2-promoting microparticles are synergistic in promoting tissue revascularization in a murine hindlimb ischemia model. However, the macrophages were rapidly cleared from the site of injury (within 2 days), making it difficult to study the phenotype changes in adoptively transferred macrophages. Therefore, the goal of this project is to adoptively transfer macrophages using biomaterial scaffolds as a cell carrier, so that the macrophages are retained at the site of injury for long enough to track their phenotype changes and to observe their interactions with other cell types involved in angiogenesis. We will use porous scaffolds (as opposed to hydrogels) because other work in our lab has shown using in vitro studies that macrophage-T cell crosstalk is important for the M1-to-M2 transition of macrophages, so it is important that T cells are able to inflitrate the biomaterial carrier. In the current project, we will administer pro-inflammatory M1 macrophages to the site of injury using porous scaffolds in order to test the hypothesis that M1 macrophage crosstalk with T cells promotes Th2 differentiation in T cells, the M1-to-M2 transition in macrophages, and enhanced angiogenesis. The hypothesis is that adoptively transferred M1 macrophages will transition into a distinct M2 phenotype with enhanced angiogenic functions (compared to M0 macrophages) via crosstalk with endogenous T cells.