白介素27通过调控角质形成细胞增殖参与银屑病发病的机制研究

Psoriasis is a common immune mediated chronic inflammatory skin disease. It can involve patients' skin, nails, mucosa and joints, which seriously endanger patients' physical and mental health. There is no effective treatment for psoriasis. Understanding the pathogenesis of psoriasis will provide a direction for the molecular biological targets for the prevention and treatment of psoriasis. Our previous study showed that in skin lesions of CD301b-depleted mice and IL-27R knockout mouse the keratinocyte proliferation rate and the wound healing rate was significantly lower than that in normal mice, and given recombinant IL-27 therapy can reverse the process. IL-27 can inhibit the expression of terminal differentiation molecular markers in HaCaT cells and promote the expression of the proliferating molecular markers. The transcriptional sequence and enrichment gene analysis of HaCaT cells treated with IL-27 showed that the expression level of JAK/STAT signaling pathway was up-regulated. In view of the main manifestation of psoriasis is the excessive proliferation of keratinocytes, the expression level of IL-27 in the skin lesions of patients with psoriasis was significantly increased, the results of our previous study suggest that IL-27 may be involved in the pathogenesis of psoriasis by promoting the proliferation of keratinocytes. Therefore, we speculate that the binding of IL-27 to receptor in psoriatic lesions may promote the abnormal proliferation of keratinocytes and participate in the occurrence and development of psoriasis by activating JAK/STAT signaling pathway.

银屑病是一种常见的免疫介导的慢性炎症性皮肤病，目前无有效治疗方法。我们前期研究结果显示在CD301b-depleted小鼠（不产生IL-27）和IL-27Rα敲除小鼠皮肤损伤处角质形成细胞的增殖速度明显低于正常小鼠，伤口的愈合速度下降，给予重组IL-27治疗可以逆转这一过程。IL-27可以抑制HaCaT细胞的终末分化分子标记物表达，促进增殖分子标记物的表达。对IL-27处理后的HaCaT细胞进行转录组测序及基因富集分析显示JAK/STAT信号通路表达水平上调。鉴于银屑病的主要表现是角质形成细胞的过度增殖，IL-27在银屑病患者皮损处表达水平又显著升高，结合我们前期的研究结果表明在银屑病患者中IL-27可能通过促进角质形成细胞的增殖参与其发病机制。由此，我们推测在银屑病皮损处IL-27与受体结合可能通过激活JAK/STAT信号通路，促进角质形成细胞的异常增殖，参与银屑病的发生和发展。

角质形成细胞的异常增殖参与了银屑病的发生和发展。本次研究探讨了IL-27促进角质形成细胞增殖的关键基因及分子机制。采用的方法包括转录组测序预测IL-27干预角质形成细胞的信号通路和关键基因；IL-27、AMG-9810（EGFR通路激活剂）干预原代角质形成细胞和人永生化角质形成细胞HaCaT；CCK-8法检测细胞活力，生化实验检测葡萄糖（Glu）、乳酸（LA）、ATP的含量，流式细胞术检测线粒体膜电位，Mito Tracker Green染色检测线粒体数量，Western blot检测CyclinE、CyclinB1、葡萄糖转运蛋白1（GLUTI）、己糖激酶2（HK2）、乳酸脱氢酶A（LDHA）、磷酸甘油酸激酶1（PGK1）、磷酸化线粒体动力相关蛋白1（pDRP1（s637））、线粒体融合蛋白2（MFN2）、p-EGFR、p-PI3K、p-Akt表达水平等。结果显示差异基因富集的信号通路主要包括糖酵解/糖原异生、PI3K-Akt信号通路等，miR-7-5p和EGFR是关键基因。IL-27抑制p-EGFR、pPI3K、p-Akt蛋白水平，提高细胞活力、CyclinE和CyclinB1蛋白水平，而这些作用被AMG-9810部分逆转。IL-27显著增加线粒体膜电位和线粒体数量，显著升高GLUTI、HK2、LDHA、PGK1、pDRP1（s637）、MFN2蛋白的表达和LA含量，显著降低Glu和ATP含量。以上结果提示IL-27通过促进糖酵解，增强线粒体功能并促进线粒体融合，靶向抑制EGFR/PI3K/Akt信号通路上调Cyclin E和Cyclin B1蛋白表达等途径促进角质形成细胞增殖。EGFR信号通路可能受到miR-7-5p的调控。本研究揭示了IL-27刺激的角质形成细胞中差异基因的表达谱及富集通路，通过构建lncRNA-miRNA-mRNA网络和PPI网络，并进行功能实验说明了IL-27可能通过促进糖酵解，增强线粒体功能并促进线粒体融合，靶向抑制EGFR/PI3K/Akt信号通路上调Cyclin E和Cyclin B1蛋白的表达，从而促进角质形成细胞的增殖。EGFR/PI3K/Akt信号通路可能受到miR-7-5p的调控。本研究为将来寻找新的银屑病治疗靶点和探索表皮愈合新途径提供了基础。