Gauvrit Sébastien, Philippe Josette, Lesage Matthieu, Tjwa Marc, Godin Isabelle, Germain Stéphane
Collège de France, Center for Interdisciplinary Research in Biology (CIRB), 11, place Marcelin Berthelot, Paris F-75005, France.
Vasc Cell. 2014 Apr 1;6(1):9. doi: 10.1186/2045-824X-6-9.
Dicer is an RNase III enzyme that cleaves double stranded RNA and generates functional interfering RNAs that act as important regulators of gene and protein expression. Dicer plays an essential role during mouse development because the deletion of the dicer gene leads to embryonic death. In addition, dicer-dependent interfering RNAs regulate postnatal angiogenesis. However, the role of dicer is not yet fully elucidated during vascular development.
In order to explore the functional roles of the RNA interference in vascular biology, we developed a new constitutive Cre/loxP-mediated inactivation of dicer in tie2 expressing cells.
We show that cell-specific inactivation of dicer in Tie2 expressing cells does not perturb early blood vessel development and patterning. Tie2-Cre; dicerfl/fl mutant embryos do not show any blood vascular defects until embryonic day (E)12.5, a time at which hemorrhages and edema appear. Then, midgestational lethality occurs at E14.5 in mutant embryos. The developing lymphatic vessels of dicer-mutant embryos are filled with circulating red blood cells, revealing an impaired separation of blood and lymphatic vasculature.
Thus, these results show that RNA interference perturbs neither vasculogenesis and developmental angiogenesis, nor lymphatic specification from venous endothelial cells but actually provides evidence for an epigenetic control of separation of blood and lymphatic vasculature.
Dicer是一种核糖核酸酶III，可切割双链RNA并产生功能性干扰RNA，这些干扰RNA作为基因和蛋白质表达的重要调节因子发挥作用。Dicer在小鼠发育过程中起着至关重要的作用，因为dicer基因的缺失会导致胚胎死亡。此外，依赖Dicer的干扰RNA调节出生后的血管生成。然而，在血管发育过程中，Dicer的作用尚未完全阐明。
为了探究RNA干扰在血管生物学中的功能作用，我们开发了一种新的组成型Cre/loxP介导的在表达Tie2的细胞中使Dicer失活的方法。
我们发现，在表达Tie2的细胞中特异性使Dicer失活不会干扰早期血管发育和模式形成。Tie2-Cre;dicerfl/fl突变胚胎在胚胎第（E）12.5天之前未表现出任何血管缺陷，而在这个时间点会出现出血和水肿。然后，突变胚胎在E14.5时发生中期致死。Dicer突变胚胎发育中的淋巴管充满循环红细胞，这表明血液和淋巴管脉管系统的分离受损。
因此，这些结果表明，RNA干扰既不干扰血管生成和发育性血管生成，也不干扰静脉内皮细胞的淋巴管特化，但实际上为血液和淋巴管脉管系统分离的表观遗传控制提供了证据。
