长链非编码 RNA AK124826调控 Th17/Treg平衡的机制及其在多发性肌炎/皮肌炎发病中的作用

Polymyositis/dermatomyositis(PM/DM) are systemic autoimmune diseases characterized by CD4+T cells reaction are thought to be involved significantly in the pathogenesis. Recent work shown that Th17/Treg was imbalance in the patients with PM/DM, however, the molecular mechanisms under this abnormality were poorly understood. Our previous study shown that long non-coding RNA AK124826 was significantly up-regulated in the CD4+T cells from PM/DM patients, by contrast, IL-27 was down-regulated.In addition, the results from CHIP indicated that IL-27 was a target of lncRNA AK124826. Given that IL-27 was regarded as a critical regulator in the Th17/Treg differentiation, we hypotheses that lncRNA AK124826 regulate the expression of IL-27 and thus been involved in the pathogenesis of PD/DM. To address this issue, the effect of lncRNA AK124826 on the Th17/Treg differentiation was investigated by "gain and loss of function". More importantly, whether IL-27 mediated the function of lncRNA AK124826 in regulating Th17/Treg differentiation was explored. The present work will introduce us new insights into the pathogenesis of PD/DM.

多发性肌炎/皮肌炎(PM/DM)是较常见的自身免疫性疾病，发病过程中 CD4+T细胞发挥重要作用，Th17/Treg细胞数量和功能失衡，但具体发病机制尚不完全清楚。我们前期研究发现，lncRNA AK124826在 PM/DM患者CD4+T细胞中高表达，IL-27在PM/DM患者中低表达，芯片网络调控图预测 IL-27是 lncRNA AK124826的作用靶点。因此，我们提出假说：lncRNA AK124826通过靶基因 IL-27影响 Th17/Treg平衡，参与PM/DM的发病。课题组首先观察 lncRNA AK124826在 PM/DM患者中的表达特点；其次，采用慢病毒过表达和干扰技术研究 lncRNA AK124826对 PM/DM患者 Th17/Treg细胞分化的作用机制；第三，验证IL-27是lncRNA AK124826的功能靶点。本课题为治疗 PM/DM提供新的思路。

多发性肌炎/皮肌炎(PM/DM)是较常见的自身免疫性疾病，我们前期研究发现，lncRNA AK124826 在PM/DM 患者CD4+T 细胞中高表达，IL-27 在PM/DM 患者中低表达。本课题从三个方面研究，观察lncRNA AK124826 在PM/DM 患者中的表达特点；采用慢病毒过表达和干扰技术研究lncRNA AK124826 对PM/DM 患者Th17/Treg 细胞分化的作用机制；验证IL-27 是lncRNA AK124826 的功能靶点。.本研究结果发现：1、PM/DM 患者外周血中TGF-β和CK表达显著高于健康对照组升高，PM/DM 患者外周血CD4+T 细胞中Th17 细胞百分比是(3.24±1.47)%，显著高于健康对照组的(0.82±0.24)% ，PM/DM 患者外周血CD4+T细胞Treg细胞百分比是(3.27±0.45)%，显著低于对照组的(6.78±0.92)% ；2、lncRNA AK124826 慢病毒过表达载体、RNAi干扰载体转入PM/DM 患者外周血初始CD4+CD45RA+T 细胞，免疫荧光表明转染效率达到80%，荧光定量PCR检测过表达和干扰效果，结果表明表达分别上升和下调了5.6、2.2倍。在CD4+CD45RA+T 细胞中过表达lncRNA AK124826能够显著活化JAK-STAT和MAPK/P38信号通路，降低lncRNA AK124826的表达能够显著抑制上述信号通路，lncRNA AK124826过表达组Th17细胞比例显著增加，同时Treg 细胞显著减少；3、lncRNA AK124826可显著降低野生型IL-27 3’UTR的报告基因活性，表达下调30%左右，RNA 免疫共沉淀实验验证IL-27为lncRNA AK124826 的功能靶点。干扰lncRNAAK124826后，Th17细胞明显减少(1.00±0.03)%，Treg 细胞显著增加(6.13±0.64)% (P<0.01)；然而，将lncRNAAK124826和IL27同时干扰掉后，发现Th17细胞明显增加(3.12±0.19)%，Treg 细胞显著减少(3.92±0.25)%(P<0.01)。.科学意义：本课题的完成，为有效治疗PM/DM 的提供新靶点。