From the Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa.
Arterioscler Thromb Vasc Biol. 2020 Dec;40(12):2891-2909. doi: 10.1161/ATVBAHA.120.314517. Epub 2020 Oct 22.
In this work, we have sought to define growth factor requirements and the signaling basis for different stages of human vascular morphogenesis and maturation. Approach and Results: Using a serum-free model of endothelial cell (EC) tube morphogenesis in 3-dimensional collagen matrices that depends on a 5 growth factor combination, SCF (stem cell factor), IL (interleukin)-3, SDF (stromal-derived factor)-1α, FGF (fibroblast growth factor)-2, and insulin (factors), we demonstrate that VEGF (vascular endothelial growth factor) pretreatment of ECs for 8 hours (ie, VEGF priming) leads to marked increases in the EC response to the factors which includes; EC tip cells, EC tubulogenesis, pericyte recruitment and proliferation, and basement membrane deposition. VEGF priming requires VEGFR2, and the effect of VEGFR2 is selective to the priming response and does not affect factor-dependent tubulogenesis in the absence of priming. Key molecule and signaling requirements for VEGF priming include RhoA, Rock1 (Rho-kinase), PKCα (protein kinase C α), and PKD2 (protein kinase D2). siRNA suppression or pharmacological blockade of these molecules and signaling pathways interfere with the ability of VEGF to act as an upstream primer of downstream factor-dependent EC tube formation as well as pericyte recruitment. VEGF priming was also associated with the formation of actin stress fibers, activation of focal adhesion components, upregulation of the EC factor receptors, c-Kit, IL-3Rα, and CXCR4 (C-X-C chemokine receptor type 4), and upregulation of EC-derived PDGF (platelet-derived growth factor)-BB, PDGF-DD, and HB-EGF (heparin-binding epidermal growth factor) which collectively affect pericyte recruitment and proliferation.
Overall, this study defines a signaling signature for a separable upstream VEGF priming step, which can activate ECs to respond to downstream factors that are necessary to form branching tube networks with associated mural cells.
在这项工作中，我们试图确定人血管形态发生和成熟不同阶段的生长因子需求和信号基础。
我们使用一种无血清的内皮细胞（EC）在 3 维胶原基质中形成管状结构的模型，该模型依赖于 5 种生长因子组合，即干细胞因子（SCF）、白细胞介素（IL）-3、基质衍生因子-1α、成纤维细胞生长因子（FGF）-2 和胰岛素（因子），我们证明了 VEGF（血管内皮生长因子）预处理 EC 8 小时（即 VEGF 引发）会导致 EC 对这些因子的反应显著增加，包括 EC 尖端细胞、EC 管状形成、周细胞募集和增殖以及基底膜沉积。VEGF 引发需要 VEGFR2，并且 VEGFR2 的作用是选择性的，并且在没有引发的情况下不会影响因子依赖性的管状形成。VEGF 引发的关键分子和信号要求包括 RhoA、Rock1（Rho-kinase）、PKCα（蛋白激酶 Cα）和 PKD2（蛋白激酶 D2）。这些分子和信号通路的 siRNA 抑制或药理学阻断会干扰 VEGF 作为下游因子依赖性 EC 管状形成和周细胞募集的上游引发剂的能力。VEGF 引发还与肌动蛋白应力纤维的形成、焦点附着成分的激活、EC 因子受体 c-Kit、IL-3Rα 和 CXCR4（C-X-C 趋化因子受体 4）的上调以及 EC 衍生的血小板衍生生长因子（PDGF）-BB、PDGF-DD 和 HB-EGF（肝素结合表皮生长因子）的上调有关，这些都共同影响周细胞的募集和增殖。
总的来说，这项研究定义了一个可分离的上游 VEGF 引发步骤的信号特征，该步骤可以激活 EC 对下游因子作出反应，这些因子是形成具有相关壁细胞的分支管状网络所必需的。
