Exploring evolutional origins of viper venom haemorrhagic factors

探索毒蛇毒出血因子的进化起源

基本信息

批准号：
23657146
负责人：
SEHARA Atsuko
金额：
$ 2.58万
依托单位：
Kyoto University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Challenging Exploratory Research
财政年份：
2011
资助国家：
日本
起止时间：
2011 至无数据
项目状态：
已结题

项目摘要

Snake venoms are classified mainly into two categories : neurotoxic and hemorrhagic venoms. This study addressed questions on the latter venom, what are the evolutional origins of viper hemorrhagic venom proteins or how vipers acquired them during evolution. Viper haemorrhagic factors are produced as precursor soluble factors composed of two toxic polypeptide domains, a domain of haemorrhagic activity and that of anti-coagulation activity. The precursors are similar in structure to transmembrane proteins generically named as ADAMs(a disintegrin and metalloproteases). We hypothesized that viper venoms mimicked ADAMs of ancestral vertebrates that carried functions in vasculogenesis/angiogenesis and/or behaviors of blood cells. We previously showed that ADAM8 is involved in the onset of blood circulation in zebrafish embryos by live imaging of their blood vessels and erythroblasts(Iida et al., Curr Biol., 2010.). By using this imaging technique, we examined how viper venom haemorrhagic venoms affects vasculogenesis or integrity of blood vessels, As a result, we found that some of them inhibited vasculogenesis of zebrafish embryos. Then we examine whether ADAM8 ply some roles on blood vessel formation. Injection of antisense morpholino oligonucleotides against ADAM8 into eggs caused inhibitory effects on elongation of intersegmental vessels. Live imaging and electron micrographs of those embryos revealed that blood cells attached to blood vessels abnormally and gene expression in blood vessels was significantly altered in those embryos. Haemorrhagic activities of viper venom proteins could be related to regulatory roles of ADAM8 in vasculogenesis.

蛇毒液主要分为两类：神经毒性和出血性毒液。这项研究解决了有关后一种毒液的问题，毒蛇出血毒素蛋白的进化起源是什么，或者在进化过程中如何获取它们。毒蛇出血因子是由两个有毒多肽结构域，出血活性和抗凝活性的前体可溶性因子产生的。前体的结构与跨膜蛋白相似，通常称为ADAMS（拆解蛋白和金属蛋白酶）。我们假设Viper毒液模仿了祖先脊椎动物的Adams，这些脊椎动物在血管生成/血管生成和/或血细胞行为中携带功能。我们先前表明，ADAM8通过实时成像血管和红细胞的实时成像参与了斑马鱼胚胎的血液循环发作（Iida等，Curr Biol。，2010年）。通过使用这种成像技术，我们检查了毒蛇毒液出血毒液如何影响血管的血管生成或完整性，因此，我们发现其中一些抑制了斑马鱼胚胎的血管生成。然后，我们检查ADAM8是否在血管形成上发挥了作用。注射反义的形态寡核苷酸对ADAM8的卵子对卵会对细胞间段血管伸长的抑制作用。这些胚胎的活成像和电子显微照片表明，在这些胚胎中，血管上附着在血管上附着的血细胞和血管中的基因表达显着改变。毒蛇毒素的出血活性可能与ADAM8在血管发生中的调节作用有关。