Reprogramming Macrophages to Improve Vascular Healing in Diabetes

患有糖尿病的美国退伍军人伤口愈合受损是发病率和死亡率的主要来源，因为 以及退伍军人管理局医疗保健系统的巨大财政压力。目前的治疗模式，包括 清创坏死组织、控制感染、局部溃疡护理、机械卸载和管理 血糖水平，充其量是适度有效的。尽管在这一领域进行了大量研究，但关键分子 调控血管生成导向的伤口愈合的机制仍然没有得到最低限度的定义。最近，我们的团队 确认炎性巨噬细胞产生血管内皮生长因子-A在随后的血管生成中的重要作用 充分愈合伤口所需的动脉生成。初步数据支持血管内皮生长因子-A的表达是 与“交替激活”或伤口愈合相关的“典型炎症”巨噬细胞增多 巨噬细胞。我们的初步数据还证实了巨噬细胞促血管生成血管内皮生长因子-A亚型的表达 依赖于强效炎症细胞因子IL-1β的表达。巨噬细胞缺失的动物 IL-1β显示巨噬细胞血管内皮生长因子-A表达严重受损，从而导致 血管生成和动脉生成。我们已经开始定义一条机制途径，通过它自分泌IL-1β- IL-1R信号促进血管生成原VEGF-A的转录，部分是通过激活NF-kB和 IL-1R下游的STAT3。我们试图了解糖尿病对巨噬细胞的影响。 促血管生成机制。实验性糖尿病小鼠的伤口愈合完全延迟 股动脉后肢缺血模型真皮厚度穿孔活检模型及血流灌注恢复 结扎术。从糖尿病小鼠分离的巨噬细胞对IL-1β的炎症反应减弱 通过减少IL-1R信号复杂成分的表达以及随之而来的VEGF-A的减少 表达，与巨噬细胞IL-1β缺失模型一致。主要的假设是糖尿病 糖尿病导致巨噬细胞IL-1β依赖的血管内皮生长因子-A表达减少，从而导致损伤 创伤愈合依赖血管生成，符合巨噬细胞IL-1β缺失模型。我们寻求1) 破坏巨噬细胞IL-1β信号依赖的促血管生成血管内皮生长因子-A亚型表达 是糖尿病血管生成和伤口愈合受损的主要机制；和2)确认缺陷 糖尿病患者单核/巨噬细胞IL-1R信号依赖的血管内皮生长因子-A的表达 尽管有常规护理标准，但仍有慢性下肢溃疡。通过将炎性巨噬细胞定义为关键， 伤口愈合所需的早期血管生成驱动因素，我们建议的研究支持一种范式 从激活伤口愈合所需的抗炎巨噬细胞策略转变，允许 用于促进炎性巨噬细胞适当激活的巨噬细胞再编程策略 最终导致依赖血管生成的伤口愈合。

Impaired wound healing in U.S. veterans with diabetes mellitus is a major source of morbidity and mortality as well as a large financial strain on the VA health care system. Current treatment paradigms, including debridement of necrotic tissue, infection control, local ulcer care, mechanical off-loading, and management of blood glucose levels, are modestly effective at best. Despite much research in this area, the critical molecular mechanisms regulating angiogenesis-directed wound healing remain minimally defined. Recently, our group identified an important role for inflammatory macrophage VEGF-A production in consequent angiogenesis/ arteriogenesis required for adequate wound healing. Preliminary data support that VEGF-A expression is increased in “classic inflammatory” macrophages relative to “alternatively activated” or wound healing macrophages. Our preliminary data also identified that macrophage proangiogenic VEGF-A isoform expression is dependent on expression of the potent inflammatory cytokine, IL-1β. Animals with macrophage deletion of IL-1β demonstrated severely impaired macrophage VEGF-A expression and consequent decreases in angiogenesis and arteriogenesis. We have begun to define a mechanistic pathway, whereby autocrine IL-1β- IL-1R signaling promotes transcription of proangiogenic VEGF-A, in part, through activation of NF-kB and STAT3 downstream of the IL-1R. We seek to understand the impact of diabetes on this macrophage proangiogenic mechanism. Mice with experimental diabetes have profound delays in wound healing in a full thickness dermal punch biopsy model and perfusion recovery in a hind limb ischemia model of femoral artery ligation. Isolated macrophages from these diabetic mice demonstrated reduced inflammatory response to IL-1β via reduced expression of IL-1R signaling complex components along with consequent reductions in VEGF-A expression, consistent with the macrophage IL-1β-deletion model. The primary hypothesis is that diabetes mellitus results in reduced macrophage IL-1β-dependent VEGF-A expression with consequent impairment in angiogenesis-dependent wound healing, consistent with the macrophage IL-1β-deletion model. We seek to 1) demonstrate disrupted macrophage IL-1β signaling-dependent proangiogenic VEGF-A isoform expression to be a major mechanism of impaired angiogenesis and wound healing in DM; and 2) validate defective monocyte/macrophage IL-1R signaling-dependent VEGF-A expression from patients with DM who develop chronic lower extremity ulcers despite usual standard of care. By defining inflammatory macrophages as key, early drivers of angiogenesis required for adequate wound healing, our proposed studies support a paradigm shift away from an anti-inflammatory macrophage strategy being required to activate wound healing, allowing for macrophage reprograming strategies that promote appropriate activation of inflammatory macrophages toward consequent angiogenesis-dependent wound healing.