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

摘要 功能障碍性血管生成与影响美国数千万患者的几种病理学有关。 一个人缺乏健康的血管形成可导致致命的并发症，包括组织死亡和肢体坏死。 截肢，并且目前的解决方案不能促进稳定的脉管系统。因此，需要制定战略 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， 巨噬细胞是促血管生成细胞疗法的有吸引力的靶标。强烈 巨噬细胞对环境刺激有反应，显示出促炎性（M1） 在早期愈合中，M2表型占主导地位，然后炎症较小的M2表型占主导地位。虽然角色 巨噬细胞表型在血管生成中的作用尚不清楚，研究表明，M1巨噬细胞 诱导新血管发芽，然后M2巨噬细胞促进稳定。在体内，M2群体 可以来自循环单核细胞，或来自预先存在的M1巨噬细胞的表型转换，但它 目前还不清楚每一组的存在程度或它们对血管生成的贡献。我们先前已经 显示IL-4导致M1激活的巨噬细胞转变为M2表型， 血管生成功能，与IL-4处理的M0巨噬细胞相比。我们假设M1衍生的M2 巨噬细胞是血管生成所必需的独特表型， 生物材料将增强体内血管生成。目标1将彻底研究M0- 衍生和M1衍生的M2巨噬细胞体内使用下一代测序，产生独特的基因 每个组的签名和功能表型。在目标2中，PLGA微粒将负载有M2-M3。 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作用。的 然后将巨噬细胞注射到伤口愈合的鼠模型中，并且随着微粒降解并 释放辛伐他汀，药物将促进细胞内M2极化。据估计，该集团正在 M1到M2转变将增强血管生成。这项研究将增加我们对以下方面作用的理解： 巨噬细胞表型在血管生成过程中，并将导致翻译促血管生成生物材料为基础的 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.