Department of Plastic and Hand Surgery, University of Erlangen-Nuremberg, Krankenhausstr 12 91054, Erlangen, Germany.
BMC Biotechnol. 2012 Dec 6;12:94. doi: 10.1186/1472-6750-12-94.
Guanylate binding protein-1 (GBP-1) is a large GTPase which is actively secreted by endothelial cells. It is a marker and intracellular inhibitor of endothelial cell proliferation, migration, and invasion. We previously demonstrated that stable expression of GBP-1 in murine endothelial progenitor cells (EPC) induces their premature differentiation and decreases their migration capacity in vitro and in vivo. The goal of the present study was to assess the antiangiogenic capacity of EPC expressing GBP-1 (GBP-1-EPC) and their impact on blood vessel formation in an axially vascularized 3-D bioartificial construct in vivo.
Functional in vitro testing demonstrated a significant increase in VEGF secretion by GBP-1-EPC after induction of cell differentiation. Undifferentiated GBP-1-EPC, however, did not secrete increased levels of VEGF compared to undifferentiated control EPC expressing an empty vector (EV-EPC). In our In vivo experiments, we generated axially vascularized tissue-engineered 3-D constructs. The new vascular network arises from an arterio-venous loop (AVL) embedded in a fibrin matrix inside a separation chamber. Total surface area of the construct as calculated from cross sections was larger after transplantation of GBP-1-EPC compared to control EV-EPC. This indicated reduced formation of fibrovascular tissue and less resorption of fibrin matrix compared to constructs containing EV-EPC. Most notably, the ratio of blood vessel surface area over total construct surface area in construct cross sections was significantly reduced in the presence of GBP-1-EPC. This indicates a significant reduction of blood vessel density and thereby inhibition of blood vessel formation from the AVL constructs caused by GBP-1. In addition, GBP-1 expressed from EPC significantly reduced cell apoptosis compared to GBP-1-negative controls.
Transgenic EPC expressing the proinflammatory antiangiogenic GTPase GBP-1 can reduce blood vessel density and inhibit apoptosis in a developing bioartificial vascular network and may become a new powerful tool to manipulate angiogenetic processes in tissue engineering and other pathological conditions such as tumour angiogenesis.
鸟苷酸结合蛋白-1（GBP-1）是一种积极由内皮细胞分泌的大 GTPase。它是内皮细胞增殖、迁移和侵袭的标志物和细胞内抑制剂。我们之前证明，在鼠内皮祖细胞（EPC）中稳定表达 GBP-1 会诱导其过早分化，并降低其在体外和体内的迁移能力。本研究的目的是评估表达 GBP-1 的 EPC（GBP-1-EPC）的抗血管生成能力及其对体内轴向血管化 3-D 生物人工构建物中血管形成的影响。
功能体外测试表明，细胞分化诱导后，GBP-1-EPC 的 VEGF 分泌显著增加。然而，与表达空载体（EV-EPC）的未分化对照 EPC 相比，未分化的 GBP-1-EPC 并未分泌增加水平的 VEGF。在我们的体内实验中，我们生成了轴向血管化的组织工程 3-D 构建物。新的血管网络源自嵌入纤维蛋白基质中的动静脉环（AVL），位于分离室内部。从横截面计算的构建物总表面积在移植 GBP-1-EPC 后比对照 EV-EPC 更大。这表明与含有 EV-EPC 的构建物相比，纤维血管组织的形成减少，纤维蛋白基质的吸收减少。值得注意的是，在存在 GBP-1-EPC 的情况下，构建物横截面中血管表面积与总构建物表面积的比例显著降低。这表明血管密度显著降低，从而抑制了源自 AVL 构建物的血管形成。此外，与 GBP-1 阴性对照相比，从 EPC 表达的 GBP-1 显著减少了细胞凋亡。
表达促炎抗血管生成 GTPase GBP-1 的转基因 EPC 可降低正在发育的生物人工血管网络中的血管密度并抑制细胞凋亡，可能成为在组织工程和其他病理条件（如肿瘤血管生成）中操纵血管生成过程的新有力工具。
