Table_5_miR-155 Contributes to the Immunoregulatory Function of Human Mesenchymal Stem Cells.docx

ObjectivesMesenchymal stem/stromal cells (MSCs) are widely investigated in regenerative medicine thanks to their immunomodulatory properties. They exert their anti-inflammatory function thanks to the secretion of a number of mediators, including proteins and miRNAs, which can be released in the extracellular environment or in the cargo of extracellular vesicles (EVs). However, the role of miRNAs in the suppressive function of MSCs is controversial. The aim of the study was to identify miRNAs that contribute to the immunomodulatory function of human bone marrow-derived MSCs (BM-MSCs).
MethodsHuman BM-MSCs were primed by coculture with activated peripheral blood mononuclear cells (aPBMCs). High throughput miRNA transcriptomic analysis was performed using Human MicroRNA TaqMan® Array Cards. The immunosuppressive function of miRNAs was investigated in mixed lymphocyte reactions and the delayed type hypersensitivity (DTH) murine model.
ResultsUpon priming, 21 out of 377 tested miRNAs were significantly modulated in primed MSCs. We validated the up-regulation of miR-29a, miR-146a, miR-155 and the down-regulation of miR-149, miR-221 and miR-361 in additional samples of primed MSCs. We showed that miR-155 significantly reduced the proliferation of aPBMCs in vitro and inflammation in vivo, using the DTH model. Analysis of miRNA-mRNA interactions revealed miR-221 as a potential target gene that is down-regulated by miR-155 both in primed MSCs and in aPBMCs.
ConclusionHere, we present evidence that miR-155 participates to the immunosuppressive function of human BM-MSCs and down-regulates the expression of miR-221 as a possible inflammatory mediator.

研究目的：间充质干细胞/基质细胞（Mesenchymal stem/stromal cells, MSCs）因其免疫调节特性，在再生医学领域得到广泛研究。其抗炎功能的发挥依赖于多种介质的分泌，包括蛋白质与微小RNA（microRNA, miRNA），这些介质可释放至细胞外环境，或被包裹于细胞外囊泡（extracellular vesicles, EVs）中进行转运。然而，miRNA在间充质干细胞的抑制性功能中所扮演的角色仍存在争议。本研究旨在鉴定可赋予人骨髓来源间充质干细胞（bone marrow-derived MSCs, BM-MSCs）免疫调节功能的miRNA。
研究方法：将人骨髓来源间充质干细胞与活化的外周血单个核细胞（activated peripheral blood mononuclear cells, aPBMCs）共培养，完成对间充质干细胞的预激活。采用人微小RNA TaqMan®阵列卡开展高通量miRNA转录组分析。通过混合淋巴细胞反应与迟发型超敏反应（delayed type hypersensitivity, DTH）小鼠模型，探究miRNA的免疫抑制功能。
研究结果：经预激活处理后，在检测的377个miRNA中，有21个在预激活的间充质干细胞中出现显著表达调控。我们在额外的预激活间充质干细胞样本中，验证了miR-29a、miR-146a、miR-155的上调表达，以及miR-149、miR-221、miR-361的下调表达。借助迟发型超敏反应小鼠模型，我们证实miR-155可在体外显著抑制活化的外周血单个核细胞的增殖，并在体内减轻炎症反应。对miRNA与mRNA相互作用的分析显示，miR-221为潜在靶基因，在预激活的间充质干细胞与活化的外周血单个核细胞中，均被miR-155下调表达。
研究结论：本研究证实，miR-155参与人骨髓来源间充质干细胞的免疫抑制功能，并通过下调作为潜在炎症介质的miR-221实现其调控作用。