Engineering a haematopoietic stem cell niche by revitalizing mesenchymal stromal cells
Engineering a haematopoietic stem cell niche by revitalizing mesenchymal stromal cells
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DOI：
10.1038/s41556-019-0308-3
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发表时间：
2019-05-01
影响因子：
21.3
通讯作者：
Frenette, Paul S.
中科院分区：
文献类型：
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作者：
Nakahara, Fumio;Borger, Daniel K.;Frenette, Paul S.
造血干细胞(HSCs)在体内由骨髓壁龛(1，2)维持，但在体外，壁龛细胞维持HSCs的能力明显减弱。Nestin-GFP(+)间充质来源的基质细胞(MSCs)在培养过程中表达的利基因子下调，提示转录重排可能是导致HSC维持潜能降低的原因之一。通过RNA测序筛选，我们鉴定了5个编码转录因子(Klf7、Ostf1、XBP1、IRF3和IRF7)的基因，它们可以恢复培养的骨髓间充质干细胞的微环境功能。这些被激活的MSCs(RMSCs)在保持其间充质分化能力的同时，增强了HSC生态位因子的合成。与与对照MSCs共培养的HSCs相比，经rMSCs扩增的HSCs显示出更高的再扩增能力，并对致死性照射的受体小鼠具有保护作用。竞争性重组实验显示，rMSCs可扩增约7倍的功能性HSCs。RMSCs阻止了培养的HSCs中DNA损伤的积累，这是衰老和复制压力的标志。对重编程机制的分析揭示了心肌细胞增强因子2c(MEF2C)在MSCs振兴中的作用。这些结果提供了对利基转录调控的洞察，并对基于干细胞的治疗产生了影响。
Haematopoietic stem cells (HSCs) are maintained by bone marrow niches in vivo(1,2), but the ability of niche cells to maintain HSCs ex vivo is markedly diminished. Expression of niche factors by Nestin-GFP(+) mesenchymal-derived stromal cells (MSCs) is downregulated upon culture, suggesting that transcriptional rewiring may contribute to this reduced HSC maintenance potential. Using an RNA sequencing screen, we identified five genes encoding transcription factors (Klf7, Ostf1, Xbp1, Irf3 and Irf7) that restored HSC niche function in cultured bone marrow-derived MSCs. These revitalized MSCs (rMSCs) exhibited enhanced synthesis of HSC niche factors while retaining their mesenchymal differentiation capacity. In contrast to HSCs co-cultured with control MSCs, HSCs expanded with rMSCs showed higher repopulation capacity and protected lethally irradiated recipient mice. Competitive reconstitution assays revealed an approximately sevenfold expansion of functional HSCs by rMSCs. rMSCs prevented the accumulation of DNA damage in cultured HSCs, a hallmark of ageing and replication stress. Analysis of the reprogramming mechanisms uncovered a role for myocyte enhancer factor 2c (Mef2c) in the revitalization of MSCs. These results provide insight into the transcriptional regulation of the niche with implications for stem cell-based therapies.