Luo Xin, Jin Rui, Wang Fang, Jia Bo, Luan Kang, Cheng Feng-Wei, Li Lei, Sun Liang-Dan, Yang Sen, Zhang Sheng-Quan, Zhang Xue-Jun
Department of Biochemistry and Molecular Biology, Anhui Medical University, Hefei, Anhui, China.
Institute of Dermatology at the 1st Hospital, Anhui Medical University, Hefei, Anhui, China.
Exp Dermatol. 2016 Jul;25(7):544-7. doi: 10.1111/exd.12992. Epub 2016 May 12.
Interleukin (IL)-15 is an important proinflammatory cytokine that can protect epidermal keratinocytes (KCs) from ultraviolet-induced apoptosis and plays a role in the pathogenesis of psoriasis. However, the impact of IL-15 on KC differentiation remains unknown. In this study, isolated human primary epidermal KCs were treated with various concentrations of IL-15 for different times, and the expression of differentiation markers (keratin 1, involucrin and loricrin) and p53 as well as the activation of ERK, AKT and Notch induced by IL-15 in the absence or presence of Ca(2+) was detected by real-time PCR and Western blot. The results showed that stimulation with Ca(2+) alone increased the expression of KC differentiation markers and p53 and promoted the activation of Notch1. Pretreatment with IL-15 resulted in a decrease in the Ca(2+) -induced expression of KC differentiation markers and p53. Additionally, Ca(2+) continually inhibited the phosphorylation of ERK1/2 and activated AKT, and IL-15 reduced the effect of Ca(2+) on ERK1/2 and AKT. FR180204, a specific inhibitor of ERK1/2 phosphorylation, slightly attenuated the effect of Ca(2+) on the expression of differentiation markers and p53 and the activation of Notch1. In contrast, MK-2206, an inhibitor of pAKT, strongly blocked the expression of the differentiation markers and p53 and the activation of Notch1. An anti-IL-15 antibody neutralized the effect of IL-15 on KC differentiation. These results indicate that IL-15 inhibits the Ca(2+) -induced differentiation of KCs, mainly via the attenuation of Ca(2+) -stimulated PI3K-AKT signalling.
白细胞介素（IL）-15是一种重要的促炎细胞因子，可保护表皮角质形成细胞（KC）免受紫外线诱导的凋亡，并在银屑病的发病机制中起作用。然而，IL-15对KC分化的影响尚不清楚。在本研究中，将分离的人原代表皮KC用不同浓度的IL-15处理不同时间，并通过实时PCR和蛋白质印迹检测在有无Ca(2+)的情况下IL-15诱导的分化标志物（角蛋白1、兜甲蛋白和loricrin）和p53的表达以及ERK、AKT和Notch的激活。结果表明，单独用Ca(2+)刺激可增加KC分化标志物和p53的表达，并促进Notch1的激活。用IL-15预处理导致Ca(2+)诱导的KC分化标志物和p53的表达降低。此外，Ca(2+)持续抑制ERK1/2的磷酸化并激活AKT，而IL-15降低了Ca(2+)对ERK1/2和AKT的作用。FR180204是ERK1/2磷酸化的特异性抑制剂，可略微减弱Ca(2+)对分化标志物和p53表达以及Notch1激活的作用。相反，pAKT抑制剂MK-2206强烈阻断分化标志物和p53的表达以及Notch1的激活。抗IL-15抗体可中和IL-15对KC分化的作用。这些结果表明，IL-15主要通过减弱Ca(2+)刺激的PI3K-AKT信号传导来抑制Ca(2+)诱导的KC分化。
