REGULATION OF INTERLEUKIN-6 (IL-6)

这一项目的工作已于去年完成并逐步结束。 这项工作的目的是阐明前列腺素E2（PGE 2）调节IL-6和IL-10产生的机制。 PGE 2是一种有效的免疫调节剂，已知可调节多种细胞因子的产生。 IL-6和IL-10通常被PGE 2上调，而TNF-α被下调。 我们发现，PGE 2可以增加小鼠腹腔巨噬细胞产生的IL-6和IL-10的水平，但导致其增加的分子途径不同。 此外，巨噬细胞暴露于PGE 2的时间相对于添加炎症刺激显著改变了产生的细胞因子的水平。 用PGE 2预处理巨噬细胞导致巨噬细胞活化后IL-6产生减少，但这是由于IL-10水平增加的事实; IL-10是IL-6合成的有效抑制剂。 在没有IL-10的情况下，PGE 2增加IL-6的合成，无论它是在炎症刺激之前还是之后加入。 随后的实验研究了暴露于PGE 2后导致巨噬细胞IL-6和IL-10产生增加的分子途径。 响应于外源性PGE 2的IL-10的合成依赖于p38 MAP激酶的激活，而IL-6的合成则不依赖于p38 MAP激酶的激活。 这是使用对p38激酶催化活性具有选择性的抑制剂并观察两种细胞因子的RNA和蛋白质合成来记录的。 p38激酶抑制剂能够抑制活化的巨噬细胞中IL-6的产生，但这主要是由于它们同时抑制环氧合酶-2表达和内源性PGE 2合成的间接结果。 结果表明，巨噬细胞IL-10和IL-6的表达受p38 MAP激酶的差异调节。 这些研究的结果目前正在修订中，以便在同行评审的期刊上发表。

Work on this project was completed and phased out during the past year. The goal of the work was to elucidate the mechanism whereby prostaglandin E2 (PGE2) regulates IL-6 and IL-10 production. PGE2 is a potent immunomodulator and is known to regulate production of a wide array of cytokines. IL-6 and IL-10 are generally upregulated by PGE2 whereas TNF-alpha is down-regulated. We found that PGE2 could augment the levels of both IL-6 and IL-10 produced by murine peritoneal macrophages but the molecular pathways that led to their augmentation differed. Also, the time of exposure of the macrophages to PGE2 relative to addition of an inflammatory stimulus significantly altered the levels of cytokines produced. Pre-treatment of the macrophages with PGE2 resulted in diminished IL-6 production following macrophage activation but this resulted from the fact that IL-10 levels had been augmented; IL-10 is a potent inhibitor of IL-6 synthesis. In the absence of IL-10, PGE2 augmented IL-6 synthesis regardless of whether it was added prior to or after the inflammatory stimulus. Subsequent experiments investigated the molecular pathway leading to increased macrophage IL-6 and IL-10 production after exposure to PGE2. Synthesis of IL-10 in response to exogenous PGE2 was dependent upon activation of the p38 MAP kinase whereas synthesis of IL-6 was not. This was documented using inhibitors which are selective for p38 kinase catalytic activity and looking at both RNA and protein synthesis for both cytokines. p38 kinase inhibitors were able to inhibit IL-6 production in activated macrophages but this occurred primarily as an indirect result of their concurrent inhibition of cyclooxygenase-2 expression and endogenous PGE2 synthesis. The results indicated that macrophage IL-10 and IL-6 expression are differentially regulated by p38 MAP kinase. The results of these studies are currently under revision for publication in a peer-reviewed journal.