Roshak A, Jackson J R, Chabot-Fletcher M, Marshall L A
Department of Immunopharmacology, SmithKline Beecham Pharmaceuticals, King of Prussia, Pennsylvania 19406, USA.
J Pharmacol Exp Ther. 1997 Nov;283(2):955-61.
Exposure of human rheumatoid synovial fibroblasts (RSF) to interleukin 1beta (IL-1beta) results in the coordinate up-regulation of 85-kDa phospholipase A2 (PLA2) and mitogen-inducible cyclooxygenase (COX II) and subsequent biosynthesis of prostaglandin E2 (PGE2). We have recently demonstrated, through the use of oligonucleotide decoys and antisense, the participation of the proinflammatory transcription factor, nuclear factor kappaB (NFkappaB), in the regulation of the prostanoid-metabolizing enzymes. Hymenialdisine, a marine natural product has recently been characterized as an inhibitor of NFkappaB activation and exposure of IL-1-stimulated RSF-inhibited PGE2 production in a concentration-dependent manner (IC50 approximately 1 microM). Alternatively, both an analog, aldisine, and the protein kinase C inhibitor, RO 32-0432, were without affect. Direct action of hymenialdisine on IL-1-induced NFkappaB activation was demonstrated by a significant reduction (approximately 80%) in NFkappaB binding to the classical kappaB consensus motif (as assessed by electrophoretic mobility shift assay) and inhibition of stimulated p65 migration from the cytosol of treated cells (as assessed by Western analysis). Consistent with the role of NFkappaB in the transcriptional regulation of COX II and 85-kDa PLA2, hymenialdisine-treated RSF did not transcribe the respective mRNAs in response to IL-1. This led to reductions in their respective protein levels and subsequent reductions in the ability to produce PGE2. Specificity of action is suggested as IL-1-stimulated interleukin-8 (IL-8) production, which is known to be an NFkappaB-regulated event, was also inhibited by hymenialdisine, whereas IL-1-induced production of vascular endothelial growth factor, a non-NFkappaB-regulated gene, was not affected by exposure to hymenialdisine. Taken together, hymenialdisine inhibits IL-1-stimulated-RSF PGE2 formation acting predominately through modulation of NFkappaB activation and offers an interesting novel tool to evaluate the role of NFkappaB in inflammatory disease.
人类风湿性滑膜成纤维细胞（RSF）暴露于白细胞介素1β（IL-1β）会导致85-kDa磷脂酶A2（PLA2）和丝裂原诱导型环氧化酶（COX II）协同上调，随后前列腺素E2（PGE2）生物合成增加。我们最近通过使用寡核苷酸诱饵和反义技术证明，促炎转录因子核因子κB（NFκB）参与了前列腺素代谢酶的调控。膜海鞘素，一种海洋天然产物，最近被鉴定为NFκB激活的抑制剂，其对IL-1刺激的RSF的暴露以浓度依赖的方式抑制PGE2的产生（IC50约为1μM）。另外，其类似物醛海鞘素和蛋白激酶C抑制剂RO 32-0432均无此作用。通过电泳迁移率变动分析评估，膜海鞘素对IL-1诱导的NFκB激活有直接作用，表现为NFκB与经典κB共有基序的结合显著减少（约80%），并且通过蛋白质印迹分析评估，膜海鞘素抑制了受刺激的p65从处理细胞的胞质溶胶中迁移。与NFκB在COX II和85-kDa PLA2转录调控中的作用一致，经膜海鞘素处理的RSF不会因IL-1而转录相应的mRNA。这导致它们各自的蛋白质水平降低，随后产生PGE2的能力下降。膜海鞘素作用的特异性表现为，已知由NFκB调控的IL-1刺激的白细胞介素8（IL-8）的产生也受到膜海鞘素的抑制，而IL-1诱导的血管内皮生长因子（一种非NFκB调控基因）的产生不受膜海鞘素暴露的影响。综上所述，膜海鞘素主要通过调节NFκB激活来抑制IL-1刺激的RSF产生PGE2，为评估NFκB在炎症性疾病中的作用提供了一个有趣的新工具。
