Reprogramming Macrophages to Improve Vascular Healing in Diabetes

美国退伍军人糖尿病患者的伤口愈合受损是发病率和死亡率的主要来源， 以及VA医疗保健系统的巨大财政压力。目前的治疗模式，包括 坏死组织的清创、感染控制、局部溃疡护理、机械卸载和 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，但关键的分子 调节血管生成导向的伤口愈合的机制仍然最低限度地被定义。最近，我们集团 确定了炎性巨噬细胞VEGF-A的产生在随后的血管生成中的重要作用， 伤口愈合所需的动脉生成。初步数据支持VEGF-A表达是 相对于“交替激活”或伤口愈合，“典型炎性”巨噬细胞增加 巨噬细胞我们的初步数据还表明，巨噬细胞促血管生成VEGF-A亚型表达 依赖于强效炎性细胞因子IL-1β的表达。巨噬细胞缺失的动物 IL-1β表现出严重受损的巨噬细胞VEGF-A表达， 血管生成和动脉生成。我们已经开始确定一种机制途径，即自分泌IL-1β- IL-1 R信号传导促进促血管生成VEGF-A的转录，部分是通过激活NF-kB， IL-1 R下游的STAT 3。我们试图了解糖尿病对这种巨噬细胞的影响 促血管生成机制患有实验性糖尿病的小鼠在伤口愈合方面有很大的延迟， 厚皮穿刺活检模型及股动脉缺血模型灌注恢复 结扎从这些糖尿病小鼠中分离的巨噬细胞表现出对IL-1β的炎症反应降低 通过降低IL-1 R信号传导复合物组分的表达，沿着降低VEGF-A 表达，与巨噬细胞IL-1β缺失模型一致。主要假设是糖尿病 导致巨噬细胞IL-1β依赖性VEGF-A表达减少， 血管生成依赖性伤口愈合，与巨噬细胞IL-1β缺失模型一致。我们寻求（1） 证实巨噬细胞IL-1β信号传导依赖性促血管生成VEGF-A亚型表达被破坏， 是DM中血管生成和伤口愈合受损的主要机制;和2）验证缺陷 糖尿病患者单核细胞/巨噬细胞IL-1 R信号依赖性VEGF-A表达 慢性下肢溃疡，尽管常规标准治疗。通过将炎症巨噬细胞定义为关键， 充分伤口愈合所需的血管生成的早期驱动因素，我们提出的研究支持了一种范式， 从激活伤口愈合所需的抗炎巨噬细胞策略转移， 巨噬细胞重编程策略，促进炎症巨噬细胞的适当激活 从而促进血管生成依赖性伤口愈合。

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.