Guangdong Provincial Key Laboratory of Proteomics, State Key Laboratory of Organ Failured Research, Department of Pathophysiology, School of Basic Medical Science, Southern Medical University, Guangzhou, China.
Arterioscler Thromb Vasc Biol. 2020 Dec;40(12):2922-2940. doi: 10.1161/ATVBAHA.120.315151. Epub 2020 Oct 1.
In patients with peripheral artery disease, blockages in arterioles <1 mm cannot be treated surgically, and there are currently few effective medicines. Studies have shown that inflammation in ischemic tissue is related to injury recovery and angiogenesis, but insufficient attention has been paid to this area. Studies have suggested that HMGB1 (high mobility group protein 1), which is released by ischemic tissue, promotes angiogenesis, but the mechanism is not entirely clear. In this study, we tested the internalization of HMGB1 in endothelial cells and investigated a novel proangiogenic pathway. Approach and Results: Using green fluorescent protein-tagged HMGB1 to stimulate endothelial cells, we demonstrated HMGB1 internalization via dynamin and RAGE (receptor for advanced glycation end products)-dependent signaling. Using a fluorescence assay, we detected internalized protein fusion to lysosomes, followed by activation of CatB (cathepsin B) and CatL (cathepsin L). The latter promoted the release of VEGF (vascular endothelial growth factor)-A and endoglin and upregulated the capacities of cell migration, proliferation, and tube formation in endothelial cells. We identified that the cytokine-induced fragment-a key functional domain in HMGB1-mediates the internalization and angiogenic function of HMGB1. We further confirmed that HMGB1 internalization also occurs in vivo in endothelial cells and promotes angiogenesis in mouse femoral artery ligation.
In this study, we identified a novel pathway of HMGB1 internalization-induced angiogenesis in endothelial cells. This finding sheds light on the regulatory role of inflammatory factors in angiogenesis through cell internalization and opens a new door to understand the relationship between inflammation and angiogenesis in ischemic diseases.
在患有外周动脉疾病的患者中，无法通过手术治疗 <1 毫米的小动脉阻塞，并且目前有效的药物也很少。研究表明，缺血组织中的炎症与损伤恢复和血管生成有关，但对此领域的关注较少。研究表明，缺血组织释放的高迁移率族蛋白 1（HMGB1）可促进血管生成，但机制尚不完全清楚。在本研究中，我们测试了 HMGB1 在血管内皮细胞中的内化作用，并研究了一种新的促血管生成途径。
使用绿色荧光蛋白标记的 HMGB1 刺激内皮细胞，我们证明了 HMGB1 通过网格蛋白和 RAGE（晚期糖基化终产物受体）依赖性信号转导内化。通过荧光测定法，我们检测到内化的蛋白融合到溶酶体中，随后激活 CatB（组织蛋白酶 B）和 CatL（组织蛋白酶 L）。后者促进了血管内皮生长因子（VEGF）-A 和内脂素的释放，并上调了内皮细胞的迁移、增殖和管状形成能力。我们确定了细胞因子诱导的片段（HMGB1 的关键功能域）介导了 HMGB1 的内化和血管生成功能。我们进一步证实，HMGB1 内化也发生在体内的内皮细胞中，并促进了小鼠股动脉结扎后的血管生成。
在本研究中，我们鉴定了内皮细胞中 HMGB1 内化诱导血管生成的新途径。这一发现揭示了炎症因子通过细胞内化调节血管生成的调控作用，并为理解缺血性疾病中炎症与血管生成之间的关系开辟了新的途径。
