Tufró A
Department of Pediatrics, University of Virginia School of Medicine, Charlottesville, Virginia 22908-0386, USA.
Dev Biol. 2000 Nov 15;227(2):558-66. doi: 10.1006/dbio.2000.9845.
Vascular endothelial growth factor (VEGF) is required for endothelial cell differentiation, vasculogenesis, and normal glomerular vascularization. To examine whether VEGF plays a role as a chemoattractant for the developing kidney vasculature, avascular metanephric kidneys from rat embryos (E14) were cocultured with endothelial cells. To determine whether VEGF directly provides chemoattractive guidance for migration, we examined migration of endothelial cells toward VEGF-coated beads. Mouse glomerular endothelial cells expressing beta-galactosidase (MGEC) were isolated from Flk-1(+/-) heterozygous mice and passaged 4-12 times. Upon 24 h culture on collagen I gels MGEC formed a lattice or capillary-like network. Embryonic metanephroi were cocultured with MGEC on collagen I gels for 1-6 days in defined media, stained for beta-galactosidase, and examined by light microscopy. Metanephric organs induced a rearrangement of the endothelial cell lattice and attracted MGEC. MGEC invaded the metanephric organs forming capillary-like structures within and surrounding the forming nephrons. This process was accelerated and amplified by low oxygen (3% O(2)) and was prevented by anti-VEGF neutralizing antibodies. MGECs migrated toward VEGF-coated beads, whereas PBS-coated beads did not alter MGEC networks. We conclude that VEGF produced by the differentiating nephrons acts as a chemoattractant providing spatial direction to developing capillaries toward forming nephrons during metanephric development in vitro.
血管内皮生长因子（VEGF）对于内皮细胞分化、血管生成以及正常肾小球血管形成是必需的。为了研究VEGF是否作为发育中的肾脏血管系统的趋化因子发挥作用，将来自大鼠胚胎（E14）的无血管后肾与内皮细胞进行共培养。为了确定VEGF是否直接为迁移提供趋化引导，我们检测了内皮细胞向包被有VEGF的珠子的迁移情况。从Flk-1(+/-)杂合小鼠中分离出表达β-半乳糖苷酶的小鼠肾小球内皮细胞（MGEC），并传代4 - 12次。在I型胶原凝胶上培养24小时后，MGEC形成格子状或毛细血管样网络。将胚胎后肾与MGEC在I型胶原凝胶上于限定培养基中共培养1 - 6天，对β-半乳糖苷酶进行染色，并通过光学显微镜检查。后肾器官诱导内皮细胞格子重排并吸引MGEC。MGEC侵入后肾器官，在形成的肾单位内部和周围形成毛细血管样结构。低氧（3% O₂）加速并放大了这一过程，而抗VEGF中和抗体则阻止了这一过程。MGEC向包被有VEGF的珠子迁移，而包被有PBS的珠子则不改变MGEC网络。我们得出结论，在体外后肾发育过程中，分化中的肾单位产生的VEGF作为趋化因子为发育中的毛细血管向形成的肾单位提供空间方向。
