白细胞介素 33 通过 ERK/STAT3 通路下调角质形成细胞中紧密连接蛋白 1 的表达。
IL-33 down-regulates CLDN1 expression through the ERK/STAT3 pathway in keratinocytes.
机构信息
Laboratory of Cell Signaling and Nanomedicine, Department of Dermatology, Division of Brain Korea 21 Project for Biomedical Science, Korea University College of Medicine, Seoul, Republic of Korea.
Research Institute for Skin Image, Korea University College of Medicine, Seoul, Republic of Korea.
出版信息
J Dermatol Sci. 2018 Jun;90(3):313-322. doi: 10.1016/j.jdermsci.2018.02.017. Epub 2018 Mar 2.
BACKGROUND
Tight junctions (TJs) have important roles in skin barrier function. The TJ protein claudin-1 (CLDN1) is decreased in atopic dermatitis (AD). However, little is known about the mechanism of CLDN1 down-expression.
OBJECTIVE
To elucidate the effect of IL-33 on CLDN1 expression in keratinocytes.
METHODS
Normal human epidermal keratinocytes (NHEKs) and human skin equivalent models (HSEMs) were cultured in vitro in the presence of IL-33. Production of CLDN1, signal transducer and activator of transcription 3 (STAT3) and Mitogen-activated protein kinases (MAPK) expression were measured by real-time PCR, western blot and immunofluorescence assay. MAPK inhibitors and small interfering RNA were used to confirm the signal pathway of STAT3 and CLDN1. Barrier function was measured by transepithelial electric resistance (TEER) and FITC-dextran flux assays. Electrophoretic Mobility Shift Assay was used to detect STAT3 transcriptional activity.
RESULTS
Levels of CLDN1 expression were reduced in the epidermis of AD-model mice overexpressing IL-33. IL-33 down-regulated the expression of CLDN1 mRNA and protein in NHEKs and HSEMs. IL-33 attenuated transepithelial electric resistance and induced FITC-dextran flux in NHEKs. The IL-33 suppressed CLDN1 expression was regulated by an extracellular signal-regulated kinase (ERK) and signal transducer and activator of transcription 3 (STAT3). STAT3 suppressed CLDN1 expression by direct binding to the promoters.
CONCLUSION
IL-33 may down-regulate CLDN1 expression through the ERK/STAT3 pathway in keratinocytes.
背景
紧密连接（TJ）在皮肤屏障功能中具有重要作用。TJ 蛋白 Claudin-1（CLDN1）在特应性皮炎（AD）中减少。然而，CLDN1 下调的机制知之甚少。
目的
阐明 IL-33 对角质形成细胞中 CLDN1 表达的影响。
方法
体外培养正常人表皮角质形成细胞（NHEKs）和人皮肤等效模型（HSEMs），存在 IL-33。通过实时 PCR、western blot 和免疫荧光检测 CLDN1、信号转导和转录激活因子 3（STAT3）和丝裂原活化蛋白激酶（MAPK）的表达。使用 MAPK 抑制剂和小干扰 RNA 来确认 STAT3 和 CLDN1 的信号通路。通过跨上皮电阻（TEER）和 FITC-葡聚糖通量测定来测量屏障功能。电泳迁移率变动分析用于检测 STAT3 转录活性。
结果
在过表达 IL-33 的 AD 模型小鼠的表皮中，CLDN1 的表达水平降低。IL-33 下调 NHEKs 和 HSEMs 中 CLDN1 mRNA 和蛋白的表达。IL-33 减弱了 NHEKs 的跨上皮电阻并诱导了 FITC-葡聚糖通量。IL-33 抑制 CLDN1 表达受细胞外信号调节激酶（ERK）和信号转导和转录激活因子 3（STAT3）调节。STAT3 通过直接结合启动子抑制 CLDN1 表达。
结论
IL-33 可能通过 ERK/STAT3 通路下调角质形成细胞中的 CLDN1 表达。
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