To determine the role of IL-6 in bringing about the EMT, in SGEC obtained from healthy subjects. Human salivary gland (SGs) epithelial cells (SGEC) from primary Sjögren’s syndrome (pSS) are able to synthesize interleukin (IL)-6, which is a critical mediator of the SGs modifications in response to chronic inflammation. Recently, a hypothetical link between epithelial-mesenchymal transition (EMT)-dependent salivary gland fibrosis and chronic inflammatory conditions has been suggested for pSS; the present study was conducted to evaluate this link. Primary cultures of human SGEC from salivary mucoceles were stimulated with increasing concentrations of IL-6 for 24–72 h. Microscopy, RT-PCR, Real-time PCR, immunoblotting and flow cytometry were used to detect morphological changes, mRNA and protein expression of the EMT markers E-Cadherin, Vimentin and Collagen type I following IL-6 stimulation. The data collected demonstrate that IL-6 can induce SGEC to undergo a morphological and phenotypical transition to a mesenchymal phenotype, in a dose-dependent manner. Decreased mRNA levels of E-Cadherin accompanied by higher mRNA levels of Vimentin and Collagen type I were observed in the IL-6-treated cells compared to control cells (all p < 0.05). This was confirmed at the protein level, demonstrating the decreased E-Cadherin expression, while Vimentin and Collagen type I expression was increased in IL-6-treated SGEC compared to controls (all p < 0.05). The results obtained corroborate the hypothesis that dysregulated cytokines IL-6 may contribute to the EMT-dependent fibrosis, offering a more complete understanding of the role of the EMT during SGs fibrosis in pSS.

为了确定IL-6在从健康受试者获得的SGEC中引起EMT中的作用。原发性干燥综合征（pSS）的人唾液腺（SGs）上皮细胞（SGEC）能够合成白介素（IL）-6，白介素（IL）-6是SGs对慢性炎症做出反应的关键调节因子。最近，对于pSS已经提出了上皮-间质转化（EMT）依赖性唾液腺纤维化与慢性炎性疾病之间的假想联系。本研究旨在评估这一联系。IL-6浓度的增加刺激了唾液黏液囊的人SGEC的原代培养24-72 h。显微镜，RT-PCR，实时荧光定量PCR，免疫印迹和流式细胞仪检测EMT标记E-钙黏着蛋白的形态变化，mRNA和蛋白质表达，IL-6刺激后波形蛋白和I型胶原蛋白。收集的数据表明，IL-6可以以剂量依赖的方式诱导SGEC经历形态学和表型转变为间充质表型。与对照组相比，经IL-6处理的细胞中E-钙黏着蛋白的mRNA水平降低，同时波形蛋白和I型胶原蛋白的mRNA水平更高（所有p  ＜0.05）。在蛋白质水平上证实了这一点，表明E-钙黏着蛋白表达降低，而经IL-6处理的SGEC中Vimentin和I型胶原蛋白表达与对照组相比有所增加（所有p  <0.05）。获得的结果证实了细胞因子IL-6失调可能导致EMT依赖性纤维化的假说，从而更全面地了解了SGs纤维化在pSS中EMT的作用。