Department of Biomedicine, University of Basel and University Hospital Basel, Basel, Switzerland; Institute of Chemistry and Bioanalytics, University of Applied Sciences Northwestern Switzerland, Muttenz, Switzerland.
Xenotransplantation. 2013 Nov-Dec;20(6):469-80. doi: 10.1111/xen.12070. Epub 2013 Nov 1.
The JAK/STAT (Janus Tyrosine Kinase, Signal Transducers and Activators of Transcription) pathway is associated with cytokine or growth factor receptors and it is critical for growth control, developmental regulation and homeostasis. The use of porcine ocular cells as putative xenotransplants appears theoretically possible. The aim of this study was to investigate the response of various porcine ocular cells in vitro to human cytokines in regard to the activation of JAK-STAT signaling pathways.
Porcine lens epithelial cells, pigmented iris epithelial cells and pigmented ciliary body cells were used in this study. These cells were isolated from freshly enucleated porcine eyes by enzymatic digestion. Cultured cells between passages 3-8 were used in all experiments. Electromobility shift assay (EMSA), proliferation assay, immunofluorescence staining and flow cytometry were used to evaluate the JAK-STAT signaling pathway in these cells.
JAK/STAT signaling pathways could be activated in porcine pigmented epithelial ciliary body cells, in pigmented iris epithelial cells and in lens epithelial cells in response to porcine and human interferons and cytokines. All cells showed very strong STAT1 activation upon stimulation with porcine interferon-gamma. Porcine ocular cells also respond to human cytokines; IFN-alpha induced strong activation of STAT1 in EMSA, flow cytometry and immunofluorescence experiments whereas activation of STAT3 was less strong in EMSA, but strong in flow cytometry and immunofluorescence. Human recombinant IL-6 activated STAT3 and human IL-4 activated STAT6. With the help of immunofluorescence assay and flow cytometry we observed nuclear localization of STAT proteins after activation of porcine ocular cells with cytokines and interferons. Human IFN-α had an inhibitory effect on porcine ocular cells in proliferation assays.
Our study demonstrated that some types of human cytokines and interferon activate intracellular JAK-STAT signaling pathways in porcine ocular cells. We hypothesize that direct stimulation of the JAK-STAT pathway in porcine cells in response to human cytokines will lead to complications or failure, if pig-to-human ocular tissue xenotransplantation were to be carried out. For successful xenotransplantation among other obstacles there must be new approaches developed to regulate signaling pathways.
JAK/STAT（Janus 酪氨酸激酶、信号转导子和转录激活子）途径与细胞因子或生长因子受体相关，对生长控制、发育调节和体内平衡至关重要。使用猪眼部细胞作为潜在的异种移植物在理论上似乎是可行的。本研究旨在探讨各种猪眼部细胞在体外对人细胞因子的反应，以研究 JAK-STAT 信号通路的激活情况。
本研究使用猪晶状体上皮细胞、色素上皮虹膜细胞和色素睫状体细胞。这些细胞通过酶消化从新鲜取出的猪眼球中分离出来。所有实验均使用传代 3-8 代的培养细胞。采用电泳迁移率变动分析（EMSA）、增殖分析、免疫荧光染色和流式细胞术来评估这些细胞中的 JAK-STAT 信号通路。
JAK/STAT 信号通路可在猪色素上皮睫状体细胞、色素虹膜上皮细胞和晶状体上皮细胞中被激活，以响应猪和人干扰素和细胞因子。所有细胞在受到猪干扰素-γ刺激后均显示出强烈的 STAT1 激活。猪眼部细胞也对人细胞因子有反应；IFN-α 在 EMSA、流式细胞术和免疫荧光实验中强烈激活 STAT1，而 STAT3 的激活在 EMSA 中较弱，但在流式细胞术和免疫荧光中较强。人重组 IL-6 激活 STAT3，人 IL-4 激活 STAT6。通过免疫荧光分析和流式细胞术，我们观察到细胞因子和干扰素激活猪眼部细胞后 STAT 蛋白的核定位。人 IFN-α 在增殖实验中对猪眼部细胞具有抑制作用。
本研究表明，某些类型的人细胞因子和干扰素可激活猪眼部细胞内的 JAK-STAT 信号通路。我们假设，如果进行猪到人的眼部组织异种移植，猪细胞对人细胞因子的 JAK-STAT 途径的直接刺激将导致并发症或失败。为了成功进行异种移植，除了其他障碍之外，还必须开发新的方法来调节信号通路。
