Lee S C, Liu W, Dickson D W, Brosnan C F, Berman J W
Department of Pathology (Neuropathology), Albert Einstein College of Medicine, Bronx, NY 10461.
J Immunol. 1993 Apr 1;150(7):2659-67.
As part of a study on the role of cytokines in central nervous system development and dysfunction, we determined the pattern of cytokine production in highly purified cultures of microglia and astrocytes isolated from second-trimester human fetal brains. Levels of TNF-alpha, IL-1 beta, and IL-6 mRNA and protein were determined by Northern blot analysis and ELISA before and after stimulation with LPS, TNF-alpha, or IL-1 beta. In microglia, LPS induced mRNA for all three cytokines. High protein levels of IL-6 and TNF-alpha were also found in the medium, whereas IL-1 beta protein was mostly cell associated. IL-1 beta also induced message for all three cytokines, in the rank order of IL-1 beta > IL-6 > TNF-alpha. TNF-alpha induced mRNA and protein for IL-1 beta but not for TNF-alpha or IL-6. In contrast, LPS failed to stimulate either mRNA or protein expression for any of the three cytokines in astrocytes. On the other hand, IL-1 beta provided a strong stimulus for astrocytes. IL-1 beta induced mRNA and protein for both TNF-alpha and IL-6, but the kinetics of the response differed for the two cytokines. TNF-alpha mRNA and protein levels peaked early (at 4 h and 16 h, respectively) and were undetectable by 72 h, whereas IL-6 mRNA peaked later (at 16 h) and protein levels continued to accumulate in the medium through 72 h. IL-1 beta did not induce IL-1 beta mRNA or protein in astrocytes. TNF-alpha did not induce expression of any of the cytokines in astrocytes. In conclusion, our results demonstrate that cytokine production can be induced in human fetal microglia and astrocytes but that the stimuli for induction differed significantly for the two cell types. Whereas LPS was a potent stimulus for microglia, astrocytes primarily responded to IL-1 beta. The data further suggest that microglia may be key regulators of astrocyte response, working primarily through the expression of cell-associated IL-1 beta.
作为一项关于细胞因子在中枢神经系统发育和功能障碍中作用的研究的一部分，我们确定了从孕中期人胎儿脑中分离出的小胶质细胞和星形胶质细胞的高度纯化培养物中细胞因子的产生模式。在用脂多糖（LPS）、肿瘤坏死因子-α（TNF-α）或白细胞介素-1β（IL-1β）刺激之前和之后，通过Northern印迹分析和酶联免疫吸附测定（ELISA）确定TNF-α、IL-1β和IL-6的mRNA和蛋白质水平。在小胶质细胞中，LPS诱导了所有三种细胞因子的mRNA。在培养基中也发现了高水平的IL-6和TNF-α蛋白质，而IL-1β蛋白质大多与细胞相关。IL-1β也诱导了所有三种细胞因子的信使核糖核酸（mRNA），诱导强度顺序为IL-1β>IL-6>TNF-α。TNF-α诱导了IL-1β的mRNA和蛋白质，但未诱导TNF-α或IL-6的mRNA和蛋白质。相反，LPS未能刺激星形胶质细胞中任何一种细胞因子的mRNA或蛋白质表达。另一方面，IL-1β对星形胶质细胞是一种强烈的刺激物。IL-1β诱导了TNF-α和IL-6的mRNA和蛋白质，但两种细胞因子的反应动力学不同。TNF-α的mRNA和蛋白质水平在早期达到峰值（分别在4小时和16小时），到72小时时无法检测到，而IL-6的mRNA在较晚时间达到峰值（在16小时），并且蛋白质水平在培养基中持续积累至72小时。IL-1β未在星形胶质细胞中诱导IL-1β的mRNA或蛋白质。TNF-α未在星形胶质细胞中诱导任何一种细胞因子的表达。总之，我们的结果表明，细胞因子的产生可在人胎儿小胶质细胞和星形胶质细胞中诱导，但两种细胞类型的诱导刺激物有显著差异。虽然LPS是小胶质细胞的有效刺激物，但星形胶质细胞主要对IL-1β作出反应。数据进一步表明，小胶质细胞可能是星形胶质细胞反应的关键调节因子，主要通过细胞相关IL-1β的表达发挥作用。
