A conditional knockout mouse model reveals endothelial cells as the principal and possibly exclusive source of plasma factor VIII
A conditional knockout mouse model reveals endothelial cells as the principal and possibly exclusive source of plasma factor VIII
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DOI：
10.1182/blood-2014-02-555151
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发表时间：
2014-06-12
期刊：
影响因子：
20.3
通讯作者：
Montgomery, Robert R.
中科院分区：
文献类型：
--
作者：
Fahs, Scot A.;Hille, Matthew T.;Montgomery, Robert R.
凝血因子VIII(FVIII)的细胞来源仍存在争议。像许多凝血蛋白一样，FVIII是在肝脏中产生的，长期以来FVIII的合成一直与肝细胞有关。但肝外合成也会发生，越来越多的证据表明，肝细胞不负责FVIII的产生。为了确定合成FVIII的组织，我们开发了一个依赖Cre/lox的条件性基因敲除(KO)模型，在该模型中，小鼠因子VIII基因的第17和18外显子(F8)两侧是loxP位点，或者是成簇的(F8(F))。在表达Cre重组酶的细胞中，F8(F->；KO)基因失活。当F8(F)小鼠与不同组织特异性Cre品系杂交时，我们发现肝细胞特异性F8-KO小鼠与对照组没有区别，而有效的内皮-KO模型显示出严重的血友病表型，没有检测到血浆FVIII活性。造血型CRE模型更具模糊性，因此采用实验性骨髓移植来检测造血型FVIII的合成。FVII接受野生型供者骨髓移植的小鼠在造血供体细胞植入后仍然缺乏血浆FVIII活性。我们的结果表明，血管内皮细胞是血浆FVIII的主要来源，也可能是唯一来源。
The cellular source of coagulation factor VIII (FVIII) remains controversial. Like many coagulation proteins, FVIII is produced in the liver, and FVIII synthesis has long been associated with hepatocytes. But extrahepatic synthesis also occurs, and mounting evidence suggests that hepatocytes are not responsible for FVIII production. To determine the tissue that synthesizes FVIII, we developed a Cre/lox-dependent conditional knockout (KO) model in which exons 17 and 18 of the murine factor VIII gene (F8) are flanked by loxP sites, or floxed (F8(F)). In cells expressing Cre-recombinase, the floxed sequence is deleted, resulting in F8(F -> KO) gene inactivation. When F8(F) mice were crossed with various tissue-specific Cre strains, we found that hepatocyte-specific F8-KO mice are indistinguishable from controls, whereas efficient endothelial-KO models display a severe hemophilic phenotype with no detectable plasma FVIII activity. A hematopoietic Cre model was more equivocal, so experimental bone marrow transplantation was used to examine hematopoietic FVIII synthesis. FVIIInull mice that received bone marrow transplants from wild-type donors were still devoid of plasma FVIII activity after hematopoietic donor cell engraftment. Our results indicate that endothelial cells are the predominant, and possibly exclusive, source of plasma FVIII.