研究芍药苷治疗特应性皮炎的分子机制及其对皮肤miRNA的调节

Atopic dermatitis (AD) is a chronic skin disease and its incidence has been increasing rapidly during the recent years. It has been shown that AD occurs as a result of complex causes, including aberrant immunity, Fas mediated keratinocyte apoptosis and skin barrier dysfunction, and microRNAs (miRNAs) play an important role in the pathogenesis of AD. Currently, there are no ideal internal therapies available in clinical practice. Fu Fang Fu Ling Tang, a traditional Chinese medicine formula, has been clinically used for the treatment of eczema. Previously, we analyzed its effective components and paeoniflorin was identified as the main anti-inflammatory active component. Based on these results, the proposed study aims to elucidate the molecular mechanism of paeoniflorin treatment on atopic dermatitis, especially its effect on miRNA expression. For this, we will analyze the expression of miR-155, miR-21, miR-23a and their target genes, which has been implicated in the Pathogenesis of AD. Next, we will study the proliferation, apoptosis, cytokine secretion and the expression of skin barrier protein in T lymphocyte and/or keratinocyte treated by paeoniflorin. In addition, we will analyze the serum cytokines and skin barrier protein expression in AD mice model in vivo. This study will reveal the mechanism underlying paeoniflorin treatment on AD at cellular and molecular level. Also, it will be helpful for us to further understand the pathogenesis of AD. More importantly, it may offer us the new ideas to develop novel biotherapy for AD.

特应性皮炎（Atopic dermatitis，AD）是常见瘙痒性、复发性皮肤病，发病率逐年增高。AD发病包括免疫异常，Fas介导的角质形成细胞凋亡和表皮屏障缺陷机制，miRNA也在AD的发生发展过程中起重要调控作用。目前AD无理想内用治疗药物。本课题组前期分析了治疗皮炎湿疹的复方茯苓汤的有效成分，证实芍药苷是其主要抗炎活性成分。在此基础上，拟研究芍药苷治疗AD的分子机制及其对皮肤相关miRNA的调节。即芍药苷对活化的T淋巴细胞和/或角质形成细胞miRNA-155、miRNA-21、miRNA-23a及其靶基因的调节，对细胞增殖，凋亡、细胞因子及表皮屏障蛋白的影响；体内水平研究芍药苷对AD模型小鼠血清细胞因子和表皮屏障蛋白的影响，以阐明芍药苷治疗AD的分子机制和可能的作用靶标；并有助于进一步揭示AD的发病机制，提示新的治疗靶点，有望为AD的靶向治疗提供新的理论依据和备选药物。

特应性皮炎（Atopic dermatitis，AD）是常见瘙痒性、复发性皮肤病，目前无理想内用治疗药物。前期研究证实芍药苷（paeniflorin，PF）是治疗皮炎湿疹的中药复方茯苓汤的主要物质基础和抗炎成分，本课题研究了PF治疗AD的分子机制以及中重度AD患者外周血淋巴细胞的数量及其表面特异分子表型、细胞因子表达及其相互影响。结果表明，PF能抑制人外周血活化的T淋巴细胞增殖，诱导其凋亡，并抑制T淋巴细胞CD25、CD69、NF-κB信号通路中p65核转位及有丝分裂原活化的蛋白激酶通路的P38磷酸化，抑制T淋巴细胞IFN-γ水平。中重度AD患者外周血CD3+CD4+CD25highT细胞、CD3+CD4+CD25highFoxP3 + T细胞数量较对照组明显升高，且与SCORing Atopic Dermatitis (SCORAD)评分、血清IgE水平呈正相关。其外周血调节性T细胞（Treg）表面CD152、CD39、CD73、CCR4、CCR5较对照组升高， CD4+CD25+T细胞上清TGF-β1、IL-10较对照组显降低。AD组CD19+IL-10+B细胞、CD19+ CD24highCD38highB细胞较对照组升高。外周血B细胞与CD4+T细胞混合培养，AD组较对照组CD4+IL-4+T细胞、CD4+ IFN-γ+T细胞、CD4+IL-22+T细胞及CD4+T细胞表面IL-4、IFN-γ、IL-22升高，IL-17A无显著差异。.PF的抗炎作用与抑制T淋巴细胞增殖，诱导其凋亡，抑制CD25、CD69及IFN-γ有关，IkBa-NF-kB信号通路和p38激酶磷酸化参与PF介导的对人T淋巴细胞的免疫抑制。PF还可上调凋亡角质形成细胞自噬活性，对其有保护作用。本研究揭示了PF在AD治疗中的分子机制，为AD治疗提供备选药物，PF作为重要的抗炎药物值得深入研究。中重度AD患者外周血Treg数量增加，与疾病严重程度相关；Treg对自身反应性T细胞抑制功能可能存在下降或反应性T细胞对Treg的免疫抑制可能存在耐受，其表面趋化因子受体CCR4、CCR5在AD时Treg可能由外周血移至皮肤而发挥作用。AD患者B细胞具有促进CD4+T细胞分化的作用，而调节性B细胞的负向调节功能可能在AD中减弱，有助于CD4+T细胞向Th1/ Th2/Th22方向分化，促进AD发病。