文章：

CALR突变体的表达导致斑马鱼出现mpl依赖性血小板增多症

Expression of CALR mutants causes mpl-dependent thrombocytosis in zebrafish

原文发布日期：2016-10-07

DOI: 10.1038/bcj.2016.83

类型: Original Article

开放获取: 是

英文摘要：

CALR mutations are identified in about 30% of JAK2/MPL-unmutated myeloproliferative neoplasms (MPNs) including essential thrombocythemia (ET) and primary myelofibrosis. Although the molecular pathogenesis of CALR mutations leading to MPNs has been studied using in vitro cell lines models, how mutant CALR may affect developmental hematopoiesis remains unknown. Here we took advantage of the zebrafish model to examine the effects of mutant CALR on early hematopoiesis and model human CALR-mutated MPNs. We identified three zebrafish genes orthologous to human CALR, referred to as calr, calr3a and calr3b. The expression of CALR-del52 and CALR-ins5 mutants caused an increase in the hematopoietic stem/progenitor cells followed by thrombocytosis without affecting normal angiogenesis. The expression of CALR mutants also perturbed early developmental hematopoiesis in zebrafish. Importantly, morpholino knockdown of mpl but not epor or csf3r could significantly attenuate the effects of mutant CALR. Furthermore, the expression of mutant CALR caused jak-stat signaling activation in zebrafish that could be blocked by JAK inhibitors (ruxolitinib and fedratinib). These findings showed that mutant CALR activates jak-stat signaling through an mpl-dependent mechanism to mediate pathogenic thrombopoiesis in zebrafish, and illustrated that the signaling machinery related to mutant CALR tumorigenesis are conserved between human and zebrafish.

摘要翻译： 

在大约30%的JAK2/MPL未突变的骨髓增殖性肿瘤（MPNs）（包括原发性血小板增多症（ET）和原发性骨髓纤维化）中检测到CALR突变。尽管利用体外细胞系模型研究了CALR突变导致MPNs的分子发病机制，但突变CALR如何影响发育造血仍不清楚。本研究利用斑马鱼模型探讨突变CALR对早期造血的影响，并模拟人类CALR突变型MPNs。我们鉴定出三个与人类CALR同源的斑马鱼基因，分别命名为calr、calr3a和calr3b。CALR-del52和CALR-ins5突变体的表达导致造血干细胞/祖细胞增加，随后出现血小板增多，但不影响正常血管生成。CALR突变体的表达还扰乱了斑马鱼的早期发育造血。重要的是，通过吗啉寡核苷酸敲低mpl（而非epor或csf3r）可显著减弱突变CALR的影响。此外，突变CALR的表达导致斑马鱼jak-stat信号通路激活，该激活可被JAK抑制剂（鲁索替尼和菲卓替尼）阻断。这些发现表明，突变CALR通过mpl依赖性机制激活jak-stat信号通路介导斑马鱼病理性血小板生成，并证明与突变CALR肿瘤发生相关的信号机制在人类和斑马鱼之间具有保守性。

原文链接：

Expression of CALR mutants causes mpl-dependent thrombocytosis in zebrafish