[细胞因子信号抑制因子低甲基化在过敏性紫癜患儿辅助性T细胞17/调节性T细胞失衡中的作用]
[Role of hypomethylation of suppressor of cytokine signaling in T helper 17 cell/regulatory T cell imbalance in children with Henoch-Schönlein purpura].
作者信息
Chang Hong, Lin Yi, Lei Ke, Wang Fang, Zhang Qing-Qun, Zhang Qiu-Ye
机构信息
Department of Pediatric Cardiology, Nephrology and Rheumatism, Affliated Hospital of Qingdao University, Qingdao, Shandong 266003, China.
出版信息
Zhongguo Dang Dai Er Ke Za Zhi. 2019 Jan;21(1):38-44. doi: 10.7499/j.issn.1008-8830.2019.01.008.
OBJECTIVE
To investigate the association between suppressor of cytokine signaling (SOCS) hypomethylation and T helper 17 (Th17) cell/regulatory T (Treg) cell imbalance in children with Henoch-Schönlein purpura (HSP) and the immune pathogenesis of HSP.
METHODS
A total of 32 children in the acute stage of HSP who were hospitalized from May 2014 to January 2015 were enrolled as subjects, and 28 children who underwent physical examination were enrolled as normal control group. ELISA was used to measure the plasma level of interleukin-6 (IL-6). Flow cytometry was used to measure the percentages of CD4 IL-17A T cells (Th17 cells) and CD4CD25 Treg cells (Treg cells) in peripheral blood and mean fluorescence intensity (MFI) for phosphorylated-STAT3 (pSTAT3) protein in CD4 T cells. Quantitative real-time PCR was used to measure the mRNA expression of suppressor of cytokine signaling-1 (SOCS1) and suppressor of cytokine signaling-3 (SOCS3) in CD4 T cells. High-resolution melting (HRM) was used to evaluate the methylation level of the CpG islands in SOCS1 exon 2 and the CpG islands of the potential bind sites for STAT3 in the 5'-untranslated region (5'-UTR) of SOCS3 in peripheral blood mononucleated cells.
RESULTS
Compared with the normal control group, the HSP group had significant increases in plasma IL-6 concentration and MFI for pSTAT3 in CD4 T cells, as well as a significant increase in the percentage of Th17 cells and a significant reduction in the percentage of Treg cells (P<0.05). The HSP group had significantly higher mRNA expression of SOCS1 and SOCS3 in peripheral blood mononucleated cells than the normal control group (P<0.05). In the HSP group, the mRNA expression of SOCS1 and SOCS3 was negatively correlated with Th17/Treg ratio (P<0.05). The HSP group had hypomethylation of the CpG islands in SOCS1 exon 2 and the potential binding site for STAT3 in SOCS3 5'-UTR, while the normal control group had complete demethylation.
CONCLUSIONS
Low relative expression of SOCS1 and SOCS3 caused by hypomethylation may be a factor for Th17/Treg imbalance in children with HSP.
目的
探讨细胞因子信号转导抑制因子（SOCS）低甲基化与过敏性紫癜（HSP）患儿辅助性T细胞17（Th17）/调节性T（Treg）细胞失衡之间的关系以及HSP的免疫发病机制。
方法
选取2014年5月至2015年1月住院的32例处于急性期的HSP患儿作为研究对象，选取28例体检儿童作为正常对照组。采用酶联免疫吸附测定（ELISA）法检测血浆白细胞介素-6（IL-6）水平。采用流式细胞术检测外周血中CD4 IL-17A T细胞（Th17细胞）和CD4CD25 Treg细胞（Treg细胞）的百分比以及CD4 T细胞中磷酸化信号转导和转录激活因子3（pSTAT3）蛋白的平均荧光强度（MFI）。采用定量实时聚合酶链反应（qRT-PCR）检测CD4 T细胞中细胞因子信号转导抑制因子-1（SOCS1）和细胞因子信号转导抑制因子-3（SOCS3）的mRNA表达。采用高分辨率熔解曲线分析（HRM）评估外周血单个核细胞中SOCS1第2外显子的CpG岛以及SOCS3 5'-非翻译区（5'-UTR）中STAT3潜在结合位点的CpG岛的甲基化水平。
结果
与正常对照组相比，HSP组血浆IL-6浓度、CD4 T细胞中pSTAT3的MFI显著升高，Th17细胞百分比显著升高，Treg细胞百分比显著降低（P<0.05）。HSP组外周血单个核细胞中SOCS1和SOCS3的mRNA表达显著高于正常对照组（P<0.05）。在HSP组中，SOCS1和SOCS3的mRNA表达与Th17/Treg比值呈负相关（P<0.05）。HSP组SOCS1第2外显子的CpG岛以及SOCS3 5'-UTR中STAT3的潜在结合位点存在低甲基化，而正常对照组则完全去甲基化。
结论
低甲基化导致的SOCS1和SOCS3相对表达降低可能是HSP患儿Th17/Treg失衡的一个因素。
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