Blood vessel maturation in a 3-dimensional spheroidal coculture model: direct contact with smooth muscle cells regulates endothelial cell quiescence and abrogates VEGF responsiveness
Blood vessel maturation in a 3-dimensional spheroidal coculture model: direct contact with smooth muscle cells regulates endothelial cell quiescence and abrogates VEGF responsiveness
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DOI：
10.1096/fj.00-0139com
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发表时间：
2001-02-01
期刊：
影响因子：
4.8
通讯作者：
Augustin, HG
中科院分区：
文献类型：
--
作者：
Korff, T;Kimmina, S;Augustin, HG
内皮细胞（EC）和壁细胞之间的旁分泌相互作用是血管壁组装和血管成熟的关键调节因子，并定义了血管重塑的可塑性窗口。本研究旨在研究EC和平滑肌细胞（SMC）三维球体共培养系统中血管成熟的过程。共培养球体以钙依赖性方式自发分化，组织成SMC的核心和EC的表面层，从而模仿血管与表面内衬EC和下层壁细胞的生理组装。EC与SMC的共培养诱导成熟的静止EC表型，如1）EC表面层的连接复合物的数量显著增加，2）共培养的EC下调PDGF-B表达，和3）EC对经历凋亡的抗性增加所证明的。此外，与SMC共培养的EC对VEGF的刺激变得难以抵抗（在VEGF刺激下缺乏CD 34表达;在S维凝胶血管生成试验中无法以VEGF依赖性方式形成毛细血管样芽）。相反，VEGF和Ang-2的共刺激诱导源自共培养球状体的出芽血管生成，这与Ang-2介导的血管不稳定导致VEGF反应性的模型一致。Ang-2自身能够在不存在产生SMC的Ang-1的情况下刺激内皮细胞，诱导侧向片层迁移以及凝胶发芽血管生成。两者合计，数据建立球状EC/SMC系统作为一个强大的细胞。培养模型，研究血管壁中的旁分泌相互作用，并为平滑肌细胞介导的内皮细胞静止效应提供功能证据。
Paracrine interactions between endothelial cells (EC) and mural cells act as critical regulators of vessel wall assembly, vessel maturation and define a plasticity window for vascular remodeling. The present study was aimed at studying blood vessel maturation processes in a novel 3-dimensional spheroidal coculture system of EC and smooth muscle cells (SMC). Coculture spheroids differentiate spontaneously in a calcium-dependent manner to organize into a core of SMC and a surface layer of EC, thus mimicking the physiological assembly of blood vessels with surface lining EC and underlying mural cells. Coculture of EC with SMC induces a mature, quiescent EC phenotype as evidenced by 1) a significant increase in the number of junctional complexes of the EC surface layer, 2) a down-regulation of PDGF-B expression by cocultured EC, and 3) an increased resistance of EC to undergo apoptosis. Furthermore, EC cocultured with SMC become refractory to stimulation with VEGF (lack of CD34 expression on VEGF stimulation; inability to form capillary-like sprouts in a VEGF-dependent manner in a S-dimensional in gel angiogenesis assay). In contrast, costimulation with VEGF and Ang-2 induced sprouting angiogenesis originating from coculture spheroids consistent with a model of Ang-2-mediated vessel destabilization resulting in VEGF responsiveness. Ang-2 on its own was able to stimulate endothelial cells in the absence of Ang-l producing SMC, inducing lateral sheet migration as well as in gel sprouting angiogenesis. Taken together, the data establish the spheroidal EC/SMC system as a powerful cell. culture model to study paracrine interactions in the vessel wall and provide functional evidence for smooth muscle cell-mediated quiescence effects on endothelial cells.