From the Department of Regenerative Medicine Research, Institute of Biomedical Research and Innovation, Kobe, Japan (A.K.-T., Y. Okinaka, Y.T., Y. Ogawa, M.M., J.B., A.T.).
Multi-Modal Microstructure Analysis Unit, RIKEN-JEOL Collaboration Center, RIKEN, Kobe, Japan (M.M., Y.K.).
Stroke. 2020 Apr;51(4):1279-1289. doi: 10.1161/STROKEAHA.119.028072. Epub 2020 Feb 19.
Background and Purpose- Bone marrow mononuclear cells (BM-MNCs) are a rich source of hematopoietic stem cells and have been widely used in experimental therapies for patients with ischemic diseases. Activation of angiogenesis is believed to be one of major BM-MNC mode of actions, but the essential mechanism by which BM-MNCs activate angiogenesis have hitherto been elusive. The objective of this study is to reveal the mechanism how BM-MNCs activate angiogenesis. Methods- We have evaluated the effect of direct cell-cell interaction between BM-MNC and endothelial cell on uptake of VEGF (vascular endothelial growth factor) into endothelial cells in vitro. Cerebral ischemia model was used to evaluate the effects of direct cell-cell interaction with transplanted BM-MNC on endothelial cell at ischemic tissue. Results- The uptake of VEGF into endothelial cells was increased by BM-MNC, while being inhibited by blockading the gap junction. Low-molecular-weight substance was transferred from BM-MNC into endothelial cells via gap junctions in vivo, followed by increased expression of hypoxia-inducible factor-1α and suppression of autophagy in endothelial cells. The concentration of glucose in BM-MNC cytoplasm was significantly higher than in endothelial cells, and transfer of glucose homologue from BM-MNC to endothelial cells was observed. Conclusions- Our findings demonstrated cell-cell interaction via gap junction is the prominent pathway for activation of angiogenesis at endothelial cells after ischemia and provided novel paradigm that energy source supply by stem cell to injured cell is one of the therapeutic mechanisms of cell-based therapy. Visual Overview- An online visual overview is available for this article.
背景与目的-骨髓单核细胞（BM-MNC）是造血干细胞的丰富来源，已广泛应用于缺血性疾病患者的实验治疗。血管生成的激活被认为是 BM-MNC 的主要作用模式之一，但迄今为止，BM-MNC 激活血管生成的基本机制仍不清楚。本研究旨在揭示 BM-MNC 激活血管生成的机制。方法-我们评估了 BM-MNC 与内皮细胞之间直接细胞-细胞相互作用对内皮细胞摄取血管内皮生长因子（VEGF）的影响。采用脑缺血模型评估移植的 BM-MNC 与缺血组织内皮细胞之间直接细胞-细胞相互作用的影响。结果-BM-MNC 可增加内皮细胞摄取 VEGF，而阻断缝隙连接则抑制其摄取。低分子量物质通过缝隙连接从 BM-MNC 转移到内皮细胞，随后内皮细胞中缺氧诱导因子-1α表达增加，自噬受到抑制。BM-MNC 细胞质中的葡萄糖浓度明显高于内皮细胞，并且观察到葡萄糖类似物从 BM-MNC 向内皮细胞的转移。结论-我们的研究结果表明，缺血后内皮细胞血管生成的激活主要途径是通过缝隙连接进行的细胞-细胞相互作用，并提供了一个新的范例，即干细胞向受损细胞提供能量来源是基于细胞治疗的一种治疗机制。
