miR-494-3p overexpression promotes megakaryocytopoiesis in primary myelofibrosis hematopoietic stem/progenitor cells by targeting SOCS6.
miR-494-3p overexpression promotes megakaryocytopoiesis in primary myelofibrosis hematopoietic stem/progenitor cells by targeting SOCS6.
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DOI：
10.18632/oncotarget.15226
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发表时间：
2017-03-28
期刊：
影响因子：
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通讯作者：
Manfredini R
中科院分区：
文献类型：
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作者：
Rontauroli S;Norfo R;Pennucci V;Zini R;Ruberti S;Bianchi E;Salati S;Prudente Z;Rossi C;Rosti V;Guglielmelli P;Barosi G;Vannucchi A;Tagliafico E;Manfredini R
原发性骨髓纤维化（PMF）是一种慢性费城阴性骨髓增生性肿瘤，其特征是造血干细胞衍生的克隆性骨髓增生，尤其涉及巨核细胞谱系。为了更好地表征microRNA的表达改变如何可能有助于PMF发病机制，我们先前已经对PMF造血干/祖细胞（HSPC）的基因和microRNA表达谱进行了整合分析，这使我们能够鉴定miR-494- 3 p作为上调的microRNA，预测其靶向最高数量的下调的mRNA。为了阐明miR-494- 3 p在造血分化中的作用，在本研究中，我们证明了miR-494- 3 p在正常HSPC中的强制表达促进了巨核细胞生成。对miR-494- 3 p过表达的基因表达谱分析允许鉴定在microRNA过表达后和PMF CD 34+细胞中通常下调的基因。其中，细胞因子信号转导抑制因子6（SOCS 6）通过荧光素酶测定被证实是miR-494- 3 p靶点。Western blot分析显示，在miR-494- 3 p过表达的细胞中，SOCS 6蛋白水平以及STAT 3活化水平降低。此外，HSPC中SOCS 6表达的瞬时抑制表明SOCS 6沉默刺激巨核细胞生成，模拟在miR-494- 3 p过表达时观察到的表型效应。最后，为了揭示miR-494- 3 p上调对PMF发病机制的贡献，我们在PMF HSPC中进行了抑制实验，结果表明miR-494- 3 p沉默导致SOCS 6上调并损害巨核细胞分化。总之，我们的结果首次描述了miR-494- 3 p在正常HSPC分化过程中的作用，并表明其表达增加及其靶向SOCS 6的随后下调可能导致PMF患者中常见的巨核细胞增生。
Primary myelofibrosis (PMF) is a chronic Philadelphia-negative myeloproliferative neoplasm characterized by hematopoietic stem cell-derived clonal myeloproliferation, involving especially the megakaryocyte lineage. To better characterize how the altered expression of microRNAs might contribute to PMF pathogenesis, we have previously performed the integrative analysis of gene and microRNA expression profiles of PMF hematopoietic stem/progenitor cells (HSPCs), which allowed us to identify miR-494-3p as the upregulated microRNA predicted to target the highest number of downregulated mRNAs. To elucidate the role of miR-494-3p in hematopoietic differentiation, in the present study we demonstrated that miR-494-3p enforced expression in normal HSPCs promotes megakaryocytopoiesis. Gene expression profiling upon miR-494-3p overexpression allowed the identification of genes commonly downregulated both after microRNA overexpression and in PMF CD34+ cells. Among them, suppressor of cytokine signaling 6 (SOCS6) was confirmed to be a miR-494-3p target by luciferase assay. Western blot analysis showed reduced level of SOCS6 protein as well as STAT3 activation in miR-494-3p overexpressing cells. Furthermore, transient inhibition of SOCS6 expression in HSPCs demonstrated that SOCS6 silencing stimulates megakaryocytopoiesis, mimicking the phenotypic effects observed upon miR-494-3p overexpression. Finally, to disclose the contribution of miR-494-3p upregulation to PMF pathogenesis, we performed inhibition experiments in PMF HSPCs, which showed that miR-494-3p silencing led to SOCS6 upregulation and impaired megakaryocyte differentiation. Taken together, our results describe for the first time the role of miR-494-3p during normal HSPC differentiation and suggest that its increased expression, and the subsequent downregulation of its target SOCS6, might contribute to the megakaryocyte hyperplasia commonly observed in PMF patients.