Skovseth Dag K, Veuger Marjan J T, Sorensen Dag R, De Angelis Paula M, Haraldsen Guttorm
Laboratory for Immunohistochemistry and Immunopathology Institute, Department of Pathology, Rikshospitalet University Hospital, University of Oslo, Norway.
Blood. 2005 Feb 1;105(3):1044-51. doi: 10.1182/blood-2004-03-1164. Epub 2004 Oct 5.
Endostatin is a proteolytic fragment of collagen XVIII that inhibits endothelial cell migration in vitro and experimental tumor growth in vivo. To determine how endostatin affects the in vivo behavior of endothelial cells, we took advantage of a surrogate model of human angiogenesis, in which human endothelial cells are transferred to immunodeficient mice and develop into complex vessels in the course of 30 days. Systemic delivery of human yeast-derived endostatin (serum levels of 30-35 ng/mL) inhibited the number of human vessels dramatically (95% at day 20), as most endothelial cells remained suspended as single cells. The fraction of cells with a migratory phenotype (F-actin-positive, extending pseudopods) was strongly reduced (from 50% to 13% at day 10), while the number of apoptotic and mitotic cells remained unchanged. Endostatin also hampered the recruitment of alpha-smooth muscle actin-expressing perivascular cells and thus reduced the number of mature vessels (from 64.3% to 28.6% at day 30). Moreover, transcripts of pericyte-recruiting platelet-derived growth factor-B (PDGFB) were strongly reduced in endothelial cells of endostatin-treated mice. Our results are strong evidence that endostatin inhibits angiogenesis at several levels in vivo, including perivascular cell recruitment.
内皮抑素是胶原蛋白XVIII的蛋白水解片段，可在体外抑制内皮细胞迁移，并在体内抑制实验性肿瘤生长。为了确定内皮抑素如何影响内皮细胞的体内行为，我们利用了一种人类血管生成的替代模型，即将人类内皮细胞移植到免疫缺陷小鼠体内，并在30天内发育成复杂的血管。全身性递送人类酵母源内皮抑素（血清水平为30 - 35 ng/mL）可显著抑制人类血管数量（第20天时抑制95%），因为大多数内皮细胞仍以单细胞形式悬浮。具有迁移表型的细胞比例（F - 肌动蛋白阳性，伸出伪足）大幅降低（第10天时从50%降至13%），而凋亡和有丝分裂细胞的数量保持不变。内皮抑素还阻碍了表达α - 平滑肌肌动蛋白的血管周围细胞的募集，从而减少了成熟血管的数量（第30天时从64.3%降至28.6%）。此外，在内皮抑素处理的小鼠的内皮细胞中，募集周细胞的血小板衍生生长因子 - B（PDGFB）的转录本大幅减少。我们的结果有力地证明了内皮抑素在体内多个水平抑制血管生成，包括血管周围细胞的募集。
