Department of Genetics, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, SP, Brazil.
National Institute of Science and Technology in Stem Cell and for Cell Therapy (INCTC) Center for Cell Therapy (CTC) and Regional Blood Center, Ribeirão Preto, SP, Brazil.
Sci Rep. 2017 Jun 15;7(1):3627. doi: 10.1038/s41598-017-03456-8.
Regulatory T cells (Tregs) are essential regulators of immune tolerance. atRA and TGF-β can inhibit the polarization of naïve T cells into inflammatory Th17 cells, favoring the generation of stable iTregs, however the regulatory mechanisms involved are not fully understood. In this context, the roles of individual microRNAs in Tregs are largely unexplored. Naïve T cells were immunomagnetically isolated from umbilical cord blood and activated with anti-human CD2/CD3/CD28 beads in the presence of IL-2 alone (CD4) or with the addition of TGF-β and atRA (CD4). As compared to CD4, the CD4 condition allowed the generation of highly suppressive CD4CD25CD127FOXP3 iTregs. Microarray profiling allowed the identification of a set of microRNAs that are exclusively expressed upon TGF-β/atRA treatment and that are predicted to target a set of transcripts concordantly downregulated. This set of predicted targets were enriched for central components of IL-6/JAK/STAT and AKT-mTOR signaling, whose inhibition is known to play important roles in the generation and function of regulatory lymphocytes. Finally, we show that mimics of exclusively expressed miRs (namely miR-1299 and miR-30a-5p) can reduce the levels of its target transcripts, IL6R and IL6ST (GP130), and increase the percentage of FoxP3 cells among CD4CD25 cells.
调节性 T 细胞（Tregs）是免疫耐受的重要调节者。atRA 和 TGF-β 可以抑制初始 T 细胞向炎症性 Th17 细胞的极化，有利于稳定的 iTregs 的产生，然而，涉及的调节机制尚未完全理解。在这种情况下，单个 microRNAs 在 Tregs 中的作用在很大程度上尚未被探索。我们从脐带血中免疫磁珠分离出初始 T 细胞，并用 IL-2 单独（CD4）或添加 TGF-β 和 atRA（CD4）激活，与 CD4 相比，CD4 条件允许生成高度抑制性的 CD4CD25CD127FOXP3 iTregs。微阵列分析鉴定了一组仅在 TGF-β/atRA 处理时表达的 microRNAs，这些 microRNAs 预测可靶向一组一致下调的转录物。这组预测的靶标富含 IL-6/JAK/STAT 和 AKT-mTOR 信号的核心成分，其抑制作用已知在调节性淋巴细胞的产生和功能中发挥重要作用。最后，我们表明，仅表达的 miR 的模拟物（即 miR-1299 和 miR-30a-5p）可以降低其靶转录物 IL6R 和 IL6ST（GP130）的水平，并增加 CD4CD25 细胞中 FoxP3 细胞的百分比。
