Effects of Inflammatory Cytokines on Human Fetal RPE in vitro

视网膜色素上皮(RPE)通过运输液体和分泌包括细胞因子/趋化因子在内的多种分子，在维持眼球后部的动态平衡方面发挥着重要作用。在眼部炎症中，在促炎细胞因子升高的影响下，RPE的生理特性如液体运输和趋化因子的分泌等可能发生变化，从而导致疾病的恶化。为了研究这个问题，我们用肿瘤坏死因子-α、干扰素-γ和白介素1-β的混合物刺激培养的人胎儿RPE。顶端加入混合物对JV无影响。相反，基础添加使净吸水率增加8.6±2.9×7 cm-27小时-1(n=3)。双侧加压后JV增加5.5±1.3 cm-27hr-1(n=3)。混合液刺激后，12种趋化因子和3种细胞因子的分泌量显著增加。对于大多数分子来说，来自顶侧的刺激作用远强于来自基底侧的刺激，并且来自顶侧的分泌量远大于来自基底侧的分泌量。受影响最大的趋化因子是4种CC趋化因子(MCP-1、RANTES、MCP-2、MCP-3)和4种CXC趋化因子(Gro-α、IL-8、IP-10、I-TAC)。在3个独立的实验中(n=3)，对于CC趋化因子，顶端刺激使MCP-1的顶侧分泌量从6.9±1.2 ng/孔增加到106.2±15.1 ng/孔，RANTES从0增加到10.5±0.6 ng/孔，MCP-2从69.1±1.2pg/孔增加到17.1±0.7 ng/孔，MCP-3从6.5±1.4pg/孔增加到11.2±0.7 ng/孔。IL-8从140.6±9.6pg/孔增加到55.4±9.6 ng/孔，IP-10从5.1±0.3pg/孔增加到119.9±10.8 ng/孔，I-TAC从9.5±2.1pg/孔增加到44.6±1.0 ng/孔。促炎细胞因子诱导的JV激活和大多数趋化因子/细胞因子分泌到顶端的显著增加表明RPE在眼炎性疾病的急性期和慢性期的发病机制中起着关键作用。

The retinal pigment epithelium (RPE) plays an important role in maintenance of homeostasis in the back of the eye by transporting fluid and secreting a variety of molecules including cytokines/chemokines. In ocular inflammation, affected by the elevated pro-inflammatory cytokines, the physiologic properties of RPE such as fluid transport and chemokine secretion may change resulting in exacerbation of the diseases. To investigate this question, we stimulated the cultured human fetal RPE with a mixture of TNF-alpha, IFN-gamma and IL-1beta. Apical addition of the mixture produced no changes in Jv. In contrast, basal addition increased net fluid absorption by 8.6 1 2.9 ul7cm-27hr-1 (n=3). Jv increased by 5.5 1 1.3 ul7cm-27hr-1 (n=3) after addition to both sides. Stimulation with the mixture, profoundly increased the secretion of the tested 12 chemokines and 3 cytokines. For the majority of these molecules, stimulation from the apical side was much more effective than that from the basal side and the secretion from the apical side was greater by far than that from the basal side. The highly affected chemokines were four CC chemokines (MCP-1, RANTES, MCP-2, MCP-3) and four CXC chemokines (GRO-alpha, IL-8, IP-10, I-TAC). In 3 independent experiments (n=3), for CC chemokines, apical stimulation increased secretion on apical side from 6.9 + 1.2 ng/well to 106.2 + 15.1 ng/well for MCP-1, from 0 to 10.5 + 0.6 ng/well for RANTES, from 69.1 + 1.2 pg/well to 17.1 + 0.7 ng/well for MCP-2, from 6.5 + 1.4 pg/well to 11.2 + 0.7 ng/well for MCP-3. For CXC chemokines, apical stimulation increased secretion on apical side from 15.7 + 3.2 pg/well to 36.2 + 0.3 ng/well for GRO-alpha, from 140.6 + 9.6 pg/well to 55.4 + 9.6 ng/well for IL-8, from 5.1 + 0.3 pg/well to 119.9 + 10.8 ng/well for IP-10, from 9.5 + 2.1 pg/well to 44.6 + 1.0 ng/well for I-TAC. The pro-inflammatory-cytokine-induced activation of JV and the predominant increase of secretion of most chemokine/cytokines to the apical bath suggest a critical role of the RPE in the pathogenesis of acute and chronic phases of ocular inflammatory diseases.