Direct visualization of renal vascular morphogenesis in Flk1 heterozygous mutant mice
Direct visualization of renal vascular morphogenesis in Flk1 heterozygous mutant mice
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DOI：
10.1152/ajprenal.1998.275.1.f164
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发表时间：
1998-07-01
影响因子：
4.2
通讯作者：
Abrahamson, DR
中科院分区：
文献类型：
--
作者：
Robert, B;St John, PL;Abrahamson, DR
FIK1是血管内皮生长因子(VEGF)的受体酪氨酸激酶，是已知最早的内皮前体(血管母细胞)标志物。我们研究了Flk1基因被无启动子LacZ插入部分替换的杂合子小鼠，并使用β-半乳糖苷酶组织化学观察转录Flk1的细胞。在第10天(E10)胚胎，Flk1阳性的网络包围后肾胚泡，在E11，一条血管从其腹侧进入后肾，沿着嵌入的输尿管芽。然而，在这些时间点，主动脉分支并没有接触到胚胎肾脏。在新生儿中，β-半乳糖苷酶仅强烈定位于所有血管和肾小球的内皮细胞。相反，当E12肾脏在器官培养中生长6天时，只看到零星的Flk1阳性细胞，肾小球未标记，血管缺失。当器官培养的肾脏随后被移植到野生型前房时，在血管和肾小球中发现了大量Flk1阳性的内皮细胞，这些细胞都来自移植物。图像分析显示，肾小球和肾小管生成最丰富的移植物也是Flk1表达最丰富的移植物。我们得出的结论是：1)肾微血管先于肾动脉发育；2)血管母细胞分化在器官培养中被阻止，但在移植后血管生成恢复后释放；3)在体内肾发生和微血管组装是紧密耦合的。
FIK1, a receptor tyrosine kinase for vascular endothelial growth factor (VEGF), is the earliest known marker for endothelial precursors (angioblasts). We examined heterozygous mice in which the Flk1 gene was partially replaced by a promoter-less LacZ insert and used beta-galactosidase histochemistry to view cells transcribing Flk1. In day 10 (E10) embryos, a Flk1-positive network surrounded the metanephric blastema, and, at Ell, a vessel entered the metanephros from its ventral aspect alongside the ingrowing ureteric bud. However, aortic branches did not engage embryonic kidneys at these time points. In newborns, beta-galactosidase was localized exclusively and intensely to endothelial cells of all vessels and glomeruli. In contrast, when E12 kidneys grown in organ culture for 6 days were examined, only scattered Flk1-positive cells were seen, glomeruli were unlabeled, and vessels were absent. When organ-cultured kidneys were then grafted into wild-type anterior eye chambers, numerous Flk1-positive endothelial cells in vessels and glomeruli were found, all stemming from the graft. Image analysis showed that grafts with the most abundant glomerulo- and tubulogenesis were also those with the richest expression of Flk1. We conclude that 1) kidney microvessels precede renal artery development, 2) angioblast differentiation is arrested in organ culture but released on grafting when vasculogenesis resumes, and 3) nephrogenesis and microvessel assembly are tightly coupled in vivo.