Vascular defects and liver damage by the acute inactivation of the VHL gene during mouse embryogenesis
Vascular defects and liver damage by the acute inactivation of the VHL gene during mouse embryogenesis
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DOI：
10.1038/labinvest.3700431
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发表时间：
2006-07-01
影响因子：
5
通讯作者：
Schmidt, Laura S.
中科院分区：
文献类型：
--
作者：
Hong, Seung-Beom;Furihata, Mutsuo;Schmidt, Laura S.
von Hippel-Lindau（VHL）肿瘤抑制基因的失活导致中枢神经系统血管母细胞瘤、嗜铬细胞瘤和肾细胞癌的发展。VHL基因在发育过程中的生物学作用知之甚少，因为VHL无效胚胎的早期致死性。为了克服在常规敲除小鼠中观察到的早期胚胎致死性，我们引入了他莫昔芬诱导的Cre（CreER（TM））转基因用于VHL基因的阶段特异性失活。急性他莫昔芬诱导的VHL基因在E10.5的失活导致E14.5和E15.0之间的胚胎死亡，广泛出血和坏死，而同窝对照显示正常发育。对E10.5和E14.5之间VHL灭活胚胎的检查显示血管扩张、出血和坏死性肝损伤。VHL灭活胚胎在E15.0时出现严重出血和血管异常，卵黄囊内血液循环受损，这可能是胚胎死亡的原因。胚胎死亡前（E14.5）胎盘发育看起来正常;然而，在胚胎死亡后E16.5，我们观察到胎盘绒毛膜层生长减少。在小鼠胚胎成纤维细胞（MEF）中，VHL基因的失活导致缺氧诱导因子（HIF）-1 α稳定化及其靶基因VEGF和CAIX的诱导。此外，我们观察到乳酸过量生产和酸化的培养基的失活的VHL基因。因此，通过使用新型条件性VHL敲除小鼠模型，我们可以证明VHL基因通过调节HIF-1 α及其靶基因在胚胎发生期间发育的血管系统和肝脏中发挥重要作用。该模型可用于抗HIF或抗VEGF药物的体内筛选。此外，这种急性VHL失活系统可能提供一个有用的工具，在体内研究基因，导致早期胚胎致死。
Inactivation of the von Hippel-Lindau (VHL) tumor suppressor gene leads to the development of central nervous system hemangioblastomas, pheochromocytomas and renal cell carcinomas. The biological role of the VHL gene during development is poorly understood because of early lethality of VHL-null embryos. To overcome early embryo lethality observed in the conventional knockout mouse, we introduced a tamoxifen-inducible Cre (CreER (TM)) transgene for the stage specific inactivation of the VHL gene. Acute tamoxifen-induced inactivation of the VHL gene at E10.5 resulted in embryonic lethality between E14.5 and E15.0 with extensive hemorrhage and necrosis, while littermate controls showed normal development. Examination of the VHL-inactivated embryos between E10.5 and E14.5 revealed dilated blood vessels, hemorrhage and necrotizing liver damage. Concomitant with severe hemorrhage and abnormal vasculature at E15.0, blood circulation in the yolk sac was impaired in the VHL-inactivated embryos, which may be the cause of embryo death. Placental development looked normal before embryo death (E14.5); however, at E16.5 following embryo death, we observed reduced growth of the placental labyrinthine layer. Inactivation of the VHL gene resulted in hypoxia-inducible factor (HIF)-1 alpha stabilization and induction of its target genes, VEGF and CAIX, in mouse embryonic fibroblasts (MEFs). In addition, we observed lactate overproduction and acidification of culture media by the inactivation of the VHL gene. Thus, by using a novel conditional VHL knockout mouse model, we could show that the VHL gene plays an important role in the developing vasculature and liver during embryogenesis through regulation of HIF-1 alpha and its target genes. This mouse model will be useful for the screening of anti-HIF or anti-VEGF drugs in vivo. Additionally, this acute VHL inactivation system may provide a useful tool for the in vivo study of genes that cause early embryonic lethality.