The miR-23a~27a~24-2 microRNA cluster buffers transcription and signaling pathways during hematopoiesis.
The miR-23a~27a~24-2 microRNA cluster buffers transcription and signaling pathways during hematopoiesis.
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DOI：
10.1371/journal.pgen.1006887
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发表时间：
2017-07
期刊：
影响因子：
4.5
通讯作者：
Dahl R
中科院分区：
文献类型：
--
作者：
Kurkewich JL;Hansen J;Klopfenstein N;Zhang H;Wood C;Boucher A;Hickman J;Muench DE;Grimes HL;Dahl R
MicroRNA簇mirn23a先前在过表达和敲除小鼠模型中被证明以牺牲淋巴细胞发育为代价促进髓细胞发育。这种分化在造血发育早期被观察到，在成人骨髓中共同淋巴样祖细胞（CLPs）增加，所有髓系祖细胞亚群减少。多电位祖细胞（mpp）池大小不变；然而，在本报告中，我们通过流式细胞术观察到，在缺乏mirn23a的情况下，mpp的极化亚群发生了变化。此外，体外培养的MPP和分选的MPP移植表明，这些细胞在体外和体内均具有髓性电位降低和淋巴性电位增加。我们研究了mirn23a调控造血分化的机制，发现mirn23a通过调控造血转录因子和信号通路促进造血祖细胞的髓系发育。在缺乏mirn23a mirna的情况下，指导mpp向CLP转化的早期转录因子（Ikzf1、Runx1、Satb1、Bach1和Bach2）以及将CLP转化为B细胞谱系的因子（FoxO1、Ebf1和Pax5）增加。Mirn23a似乎缓冲转录因子水平，使它们不会随机达到直接分化的阈值水平。有趣的是，mirn23a还反向调节PI3K /Akt和BMP/Smad信号通路。药理抑制剂研究，结合显性活性/显性阴性生化实验，表明这两种信号通路对mirn23a调控造血分化至关重要。最后，与mirn23a是B细胞发育的生理抑制剂一致，我们观察到B细胞必需转录因子EBF1抑制mirn23a的表达。总之，我们的数据表明，mirn23a调节一系列复杂的转录和信号通路来调节成人造血。MicroRNAs （miRNAs）是一种约22个核苷酸长的小RNA分子，通过抑制靶蛋白的表达参与调节多种细胞过程。我们之前发现了一个基因（mirn23a），它编码3个mirna，控制骨髓中免疫细胞的发育。mirna促进先天免疫细胞、巨噬细胞和粒细胞的发育，同时抑制B细胞的发育。在这里，我们发现mirn23a mirna对多种蛋白的表达产生负面影响，这些蛋白参与指导血液祖细胞转变为B细胞。此外，我们观察到FoxO1和Smad蛋白的调节是两个信号通路（PI3激酶/ Akt和BMP/ Smad）的下游效应器，对指导免疫细胞发育至关重要。这是第一次观察到这些途径在血液祖细胞向免疫系统成熟细胞的承诺过程中可能被共同调节。我们观察到一个关键的B细胞蛋白抑制mirn23a的表达，这与mirn23a是一个以牺牲B细胞为代价使祖细胞进入先天免疫细胞的关键基因相一致。总之，我们证明了mirn23a对血液发育的调控是由于转录因子和信号通路的复杂调控。
MicroRNA cluster mirn23a has previously been shown to promote myeloid development at the expense of lymphoid development in overexpression and knockout mouse models. This polarization is observed early in hematopoietic development, with an increase in common lymphoid progenitors (CLPs) and a decrease in all myeloid progenitor subsets in adult bone marrow. The pool size of multipotential progenitors (MPPs) is unchanged; however, in this report we observe by flow cytometry that polarized subsets of MPPs are changed in the absence of mirn23a. Additionally, in vitro culture of MPPs and sorted MPP transplants showed that these cells have decreased myeloid and increased lymphoid potential in vitro and in vivo. We investigated the mechanism by which mirn23a regulates hematopoietic differentiation and observed that mirn23a promotes myeloid development of hematopoietic progenitors through regulation of hematopoietic transcription factors and signaling pathways. Early transcription factors that direct the commitment of MPPs to CLPs (Ikzf1, Runx1, Satb1, Bach1 and Bach2) are increased in the absence of mirn23a miRNAs as well as factors that commit the CLP to the B cell lineage (FoxO1, Ebf1, and Pax5). Mirn23a appears to buffer transcription factor levels so that they do not stochastically reach a threshold level to direct differentiation. Intriguingly, mirn23a also inversely regulates the PI3 kinase (PI3K)/Akt and BMP/Smad signaling pathways. Pharmacological inhibitor studies, coupled with dominant active/dominant negative biochemical experiments, show that both signaling pathways are critical to mirn23a’s regulation of hematopoietic differentiation. Lastly, consistent with mirn23a being a physiological inhibitor of B cell development, we observed that the essential B cell transcription factor EBF1 represses expression of mirn23a. In summary, our data demonstrates that mirn23a regulates a complex array of transcription and signaling pathways to modulate adult hematopoiesis. MicroRNAs (miRNAs) are small ~22 nucleotide long RNA molecules that are involved in regulating multiple cellular processes through inhibiting the expression of target proteins. We previously identified a gene (mirn23a) that codes for 3 miRNAs that control the development of immune cells in the bone marrow. The miRNAs promote the development of innate immune cells, macrophages and granulocytes, while repressing the development of B cells. Here we show that mirn23a miRNAs negatively affect the expression of multiple proteins that are involved in directing blood progenitor cells to become B cells. Additionally, we observed that modulation of FoxO1 and Smad proteins, downstream effectors of two signaling pathways (PI3 kinase/ Akt and BMP/ Smad), is critical to direct immune cell development. This is the first observation that these pathways are potentially coregulated during the commitment of blood progenitors to mature cells of the immune system. Consistent with mirn23a being a critical gene for committing progenitors to innate immune cells at the expense of B cells, we observed that a critical B cell protein represses the expression of mirn23a. In conclusion, we demonstrate the mirn23a regulation of blood development is due to a complex regulation of both transcription factors and signaling pathways.
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