INTRODUCTION Mesenchymal stem cells (MSCs) exert immunomodulatory functions by inducing the development and differentiation of naive T cells into T cells with an anti-inflammatory regulatory T cell (Treg) phenotype. Our previous study showed that hepatocyte growth factor (HGF) secreted by MSCs had immunomodulatory effects in the context of lipopolysaccharide (LPS) stimulation. We hypothesized that HGF is a key factor in the MSC-mediated regulation of the T helper 17 (Th17) cell/regulatory T (Treg) cell balance. METHODS We investigated the effects of MSCs on the differentiation of CD4+ T cells and the functions of Th17/Treg cells in response to LPS stimulation by performing in vitro coculture experiments. MSCs were added to the upper chambers of cell culture inserts, and CD4+ T cells were plated in the lower chambers, followed by treatment with LPS or an anti-HGF antibody. Th17 (CD4+CD3+RORrt+) and Treg (CD4+CD25+Foxp3+) cell frequencies were analysed by flow cytometry, and the expression of Th17 cell- and Treg cell-related cytokines in the CD4+ T cells or culture medium was measured by quantitative PCR (qPCR) and enzyme-linked immunosorbent assay (ELISA), respectively. Neutrophil functions were determined by flow cytometry after a coculture with Th17/Treg cells. RESULTS The percentage of CD4+CD25+Foxp3+ cells was significantly increased in the CD4+ T cell population, while the percentage of CD4+CD3+RORrt+ cells was significantly decreased after MSC coculture. However, the MSC-induced effect was significantly inhibited by the anti-HGF antibody (p < 0.05). Furthermore, MSCs significantly inhibited the CD4+ T cell expression of IL-17 and IL-6 but increased the expression of IL-10 (p < 0.05 or p < 0.01); these effects were inhibited by the anti-HGF antibody (p < 0.05). In addition, CD4+ T cells cocultured with MSCs significantly inhibited neutrophil phagocytic and oxidative burst activities (p < 0.05 or p < 0.01); however, these MSC-induced effects were inhibited by the anti-HGF antibody (p < 0.05). CONCLUSION These data suggested that MSCs induced the conversion of fully differentiated Th17 cells into functional Treg cells and thereby modulated the Th17/Treg cell balance in the CD4+ T cell population, which was partly attributed to HGF secreted by the MSCs.

中文翻译：

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间充质干细胞在体外部分通过肝细胞生长因子调节Th17 / Treg细胞平衡。

简介间充质干细胞（MSC）通过诱导幼稚T细胞的发育和分化为具有抗炎调节性T细胞（Treg）表型的T细胞发挥免疫调节功能。我们以前的研究表明，MSCs分泌的肝细胞生长因子（HGF）在脂多糖（LPS）刺激的情况下具有免疫调节作用。我们假设HGF是MSC介导的T辅助17（Th17）细胞/调节性T（Treg）细胞平衡的关键因素。方法我们通过进行体外共培养实验，研究了MSCs对LPS刺激后CD4 + T细胞分化和Th17 / Treg细胞功能的影响。将MSC加入细胞培养插入物的上腔室中，并将CD4 + T细胞铺在下腔室中，然后用LPS或抗HGF抗体治疗。通过流式细胞仪分析Th17（CD4 + CD3 + RORrt +）和Treg（CD4 + CD25 + Foxp3 +）细胞的频率，并通过定量方法检测CD4 + T细胞或培养基中Th17细胞和Treg细胞相关细胞因子的表达PCR（qPCR）和酶联免疫吸附测定（ELISA）。与Th17 / Treg细胞共培养后，通过流式细胞术确定中性粒细胞功能。结果MSC共培养后，CD4 + T细胞群体中CD4 + CD25 + Foxp3 +细胞的百分比显着增加，而CD4 + CD3 + RORrt +细胞的百分比显着降低。但是，抗HGF抗体显着抑制了MSC诱导的作用（p <0.05）。此外，MSC显着抑制IL-17和IL-6的CD4 + T细胞表达，但增加IL-10的表达（p <0.05或p <0.01）；这些作用被抗HGF抗体抑制（p <0.05）。此外，与MSC共培养的CD4 + T细胞可显着抑制嗜中性粒细胞的吞噬和氧化爆发活性（p <0.05或p <0.01）。但是，这些MSC诱导的作用被抗HGF抗体抑制（p <0.05）。结论这些数据表明，MSC诱导了完全分化的Th17细胞向功能性Treg细胞的转化，从而调节了CD4 + T细胞群中的Th17 / Treg细胞平衡，这部分归因于MSC分泌的HGF。与MSC共培养的CD4 + T细胞显着抑制嗜中性粒细胞的吞噬和氧化爆发活性（p <0.05或p <0.01）。但是，这些MSC诱导的作用被抗HGF抗体抑制（p <0.05）。结论这些数据表明，MSC诱导了完全分化的Th17细胞向功能性Treg细胞的转化，从而调节了CD4 + T细胞群中的Th17 / Treg细胞平衡，这部分归因于MSC分泌的HGF。与MSC共培养的CD4 + T细胞显着抑制嗜中性粒细胞的吞噬和氧化爆发活性（p <0.05或p <0.01）。但是，这些MSC诱导的作用被抗HGF抗体抑制（p <0.05）。结论这些数据表明，MSC诱导了完全分化的Th17细胞向功能性Treg细胞的转化，从而调节了CD4 + T细胞群中的Th17 / Treg细胞平衡，这部分归因于MSC分泌的HGF。