Laboratory for Vascular Medicine and Stem Cell Biology, Medical Research Institute, Department of Physiology, School of Medicine, Pusan National University, Yangsan, Korea.
Arterioscler Thromb Vasc Biol. 2013 Jul;33(7):1622-34. doi: 10.1161/ATVBAHA.112.301052. Epub 2013 May 2.
Although endothelial progenitor cells (EPCs) have been reported to promote neovessel formation during vascular injury, the function of supporting cells of EPCs and their interaction with EPCs during EPC isolation remain unclear.
We investigated the functional properties of 2 types of EPCs, also known as endothelial colony-forming cells (ECFCs), CD34(-)/CD34(+) cell-derived ECFCs (hybrid-dECFCs) and CD34(+) cell-derived ECFCs (stem-dECFCs), isolated using different methods, to elucidate the role of CD34(-) cell populations as cell-supporting niches. Using EPC colony-forming and insert coculture assays, we found that CD34(-) accessory cells dynamically modulate hematopoietic stem cell-derived endothelial cell progenitor commitment via angiogenic cytokines secreted by CD34(-)/CD11b(+) macrophages. On the basis of these findings, we isolated 2 types of ECFCs and investigated their bioactivities. We found that stem-dECFCs showed remarkably retarded cell growth, enhanced senescence, and decreased characteristics of ECFCs, whereas hybrid-dECFCs showed greater proliferative properties but delayed senescence. In a murine hind-limb ischemia model, hybrid-dECFCs showed significantly enhanced blood perfusion, capillary density, transplanted cell survival and proliferation, and angiogenic cytokine secretion compared with stem-dECFCs. In particular, the migratory capacity of hybrid-dECFCs was significantly enhanced, in part mediated via an augmented phosphorylation cascade of focal adhesion kinase and Src, resulting in a highly increased incorporation capacity of hybrid-dECFCs compared with stem-dECFCs. CD34(-) accessory cells of hybrid-dECFCs might be niche-supporting cells that facilitate cell survival, increase the secretion of angiogenic cytokines, and increase incorporation.
This study provided important insight into blood vessel formation and repair in ischemic diseases for ECFC-based cell therapy.
尽管已有研究报道内皮祖细胞（EPCs）可在血管损伤时促进新血管形成，但 EPC 分离过程中支持细胞的功能及其与 EPC 的相互作用尚不清楚。
我们研究了两种类型的 EPC，即内皮集落形成细胞（ECFCs），使用不同方法分离的 CD34(-)/CD34(+)细胞衍生的 ECFCs（混合-dECFCs）和 CD34(+)细胞衍生的 ECFCs（干细胞-dECFCs）的功能特性，以阐明 CD34(-)细胞群体作为细胞支持性龛的作用。通过 EPC 集落形成和插入共培养测定，我们发现 CD34(-)辅助细胞通过 CD34(-)/CD11b(+)巨噬细胞分泌的血管生成细胞因子动态调节造血干细胞衍生的内皮细胞祖细胞的定向。基于这些发现，我们分离了两种类型的 ECFCs 并研究了它们的生物活性。我们发现干细胞-dECFCs 的细胞生长明显减慢、衰老加速且丧失 ECFCs 的特征，而混合-dECFCs 则表现出更强的增殖能力和延迟衰老。在小鼠后肢缺血模型中，与干细胞-dECFCs 相比，混合-dECFCs 显示出明显增强的血液灌注、毛细血管密度、移植细胞存活和增殖以及血管生成细胞因子分泌。特别是，混合-dECFCs 的迁移能力显著增强，部分原因是粘着斑激酶和 Src 的磷酸化级联反应增强，导致混合-dECFCs 的整合能力比干细胞-dECFCs 显著提高。混合-dECFCs 的 CD34(-)辅助细胞可能是促进细胞存活、增加血管生成细胞因子分泌并增加整合的龛支持细胞。
本研究为基于 EPC 的细胞治疗缺血性疾病中的血管形成和修复提供了重要的见解。
