Designing Biomaterials to Promote the M1-to-M2 Macrophage Transition and Enhance Angiogenesis

摘要 在美国，功能失调的血管生成与影响数千万患者的几种病理有关。 独自一人。缺乏健康的血管形成可导致致命的并发症，包括组织死亡和四肢 截肢，目前的解决方案不能促进稳定的血管形成。因此，存在对战略的需求。 这可以在整个血管生成过程中支持健康的血管形成。作为高级别的监管机构 在血管生成和愈合方面，巨噬细胞是促血管生成细胞治疗的一个有吸引力的靶点。强烈地 巨噬细胞对环境刺激的反应已被证明具有促炎作用(M1)。 在愈合早期的表型，那么炎症较少的M2表型在后期占主导地位。尽管这些角色 巨噬细胞在血管生成中的表型知之甚少，研究表明M1巨噬细胞 诱导新血管萌发，然后M2巨噬细胞促进稳定。在活体内，M2种群 可以来自循环中的单核细胞，或来自先前存在的M1巨噬细胞的表型转换，但它 目前尚不清楚每一组的存在程度或它们对血管生成的贡献。我们之前已经 研究表明，IL-4导致M1激活的巨噬细胞转变为M2表型，其中一些增加 血管生成功能，与IL-4处理的M0巨噬细胞相比。我们假设M1派生的M2 巨噬细胞是一种独特的表型，对血管生成至关重要，它促进了M1到M2的转换 生物材料将促进体内血管生成。目标1将彻底调查M0和M0之间的差异 利用下一代测序技术在体内获得M2巨噬细胞和M1巨噬细胞，产生独特的基因 每个组的签名和功能表型。在目标2中，PLGA微粒将被负载M2- 促进药物辛伐他汀，然后与M0或M1巨噬细胞共培养，以促进吞噬。这个 巨噬细胞随后将被注射到伤口愈合的小鼠模型中，随着微粒的降解和 释放辛伐他汀后，药物会促进细胞内M2极化。预计正在接受治疗的小组 从M1到M2的转变将增强血管生成。这项研究将使我们更好地理解 巨噬细胞在血管生成过程中的表型，并将导致以翻译的促血管生成生物材料为基础 细胞疗法。

Abstract Dysfunctional angiogenesis is implicated in several pathologies that affect tens of millions of patients in the U.S. alone. A lack of healthy vascularization can result in lethal complications, including tissue death and limb amputation, and current solutions fail to promote stable vasculature. Therefore, there is a demand for strategies that can support healthy vascularization throughout the angiogenic process. As high-level regulators of angiogenesis and healing, macrophages are an attractive target for pro-angiogenic cell therapies. Intensely responsive to environmental stimuli, macrophages have been shown to exhibit a pro-inflammatory (M1) phenotype in early healing, then a less-inflammatory M2 phenotype dominates later stages. Although the roles of macrophage phenotypes in angiogenesis are poorly understood, studies suggest that M1 macrophages induce sprouting of new blood vessels, then M2 macrophages promote stabilization. In vivo, the M2 population can derive from circulating monocytes, or from the phenotypic switching of pre-existing M1 macrophages, but it is unknown to what extent each group is present or what they contribute to angiogenesis. We have previously shown that IL-4 causes M1-activated macrophages to switch to an M2 phenotype with some increased angiogenic functions, compared to IL-4-treated M0 macrophages. We hypothesize that M1-derived M2 macrophages are a unique phenotype essential to angiogenesis, and that promoting the M1-to-M2 switch with biomaterials will enhance angiogenesis in vivo. Aim 1 will thoroughly investigate the differences between M0- derived and M1-derived M2 macrophages in vivo using next-generation sequencing, producing the unique gene signatures and functional phenotypes of each group. In Aim 2, PLGA microparticles will be loaded with the M2- promoting drug simvastatin, then co-cultured with M0 or M1 macrophages to facilitate phagocytosis. The macrophages will then be injected into a murine model of wound healing, and as the microparticles degrade and release simvastatin, the drug will promote M2 polarization intracellularly. It is expected that the group undergoing the M1-to-M2 transition will augment angiogenesis. This study will increase our understanding of the roles of macrophage phenotype during angiogenesis, and will result in a translational pro-angiogenic biomaterials-based cell therapy.