Nagano Shuji, Otsuka Takeshi, Niiro Hiroaki, Yamaoka Kunihiro, Arinobu Yojirou, Ogami Eiichi, Akahoshi Mitsuteru, Inoue Yasushi, Miyake Katsuhisa, Nakashima Hitoshi, Niho Yoshiyuki, Harada Mine
Medicine and Biosystemic Science, Kyushu University Graduate School of Medical Sciences, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan.
Int Immunol. 2002 Jul;14(7):733-40. doi: 10.1093/intimm/dxf038.
Neutrophils are an important cellular source of proinflammatory mediators, whose regulation may be of potential benefit for the treatment of a number of inflammatory diseases. However, the mechanisms of lipopolysaccharide (LPS)-induced neutrophil activation and its regulation by anti-inflammatory cytokines have not yet been fully elucidated. Recent studies have revealed that mitogen-activated protein kinases (MAPK) play a crucial role in the generation of proinflammatory mediators in some cell types. Therefore, we conducted this study to determine whether MAPK activation could be involved in prostaglandin E(2) (PGE(2)) production and cyclooxygenase (COX)-2 expression in LPS-stimulated human neutrophils. PD98059 (MEK1 inhibitor) and SB203580 (p38(MAPK) inhibitor) reduced PGE(2) production as well as COX-2 expression in LPS-stimulated neutrophils. In addition, both extracellular signal-regulated protein kinase (ERK) and p38(MAPK) were phosphorylated and activated in time- and dose-dependent manners. Since we previously showed that IL-10 and IL-4 similarly inhibited COX-2 expression in LPS-stimulated neutrophils, we next tested the effects of IL-10 and IL-4 on the phosphorylation and activation of both kinases. IL-10 inhibited the phosphorylation and activation of p38(MAPK), but not ERK. In addition, IL-4 caused a marginal inhibition in the activation of p38(MAPK). Taken together, these results suggest that both ERK and p38(MAPK) pathways are involved in LPS-induced COX-2 expression and PGE(2) production in neutrophils, and IL-10 and IL-4 inhibit neutrophil prostanoid synthesis by down-regulating the activation of p38(MAPK).
中性粒细胞是促炎介质的重要细胞来源，对其进行调控可能对多种炎症性疾病的治疗具有潜在益处。然而，脂多糖（LPS）诱导中性粒细胞活化的机制及其受抗炎细胞因子调控的机制尚未完全阐明。最近的研究表明，丝裂原活化蛋白激酶（MAPK）在某些细胞类型中促炎介质的产生中起关键作用。因此，我们进行了这项研究，以确定MAPK激活是否参与LPS刺激的人中性粒细胞中前列腺素E2（PGE2）的产生和环氧化酶（COX）-2的表达。PD98059（MEK1抑制剂）和SB203580（p38 MAPK抑制剂）可降低LPS刺激的中性粒细胞中PGE2的产生以及COX-2的表达。此外，细胞外信号调节蛋白激酶（ERK）和p38 MAPK均以时间和剂量依赖性方式被磷酸化并激活。由于我们之前表明IL-10和IL-4同样抑制LPS刺激的中性粒细胞中COX-2的表达，因此我们接下来测试了IL-10和IL-4对这两种激酶磷酸化和激活的影响。IL-10抑制p38 MAPK的磷酸化和激活，但不抑制ERK。此外，IL-4对p38 MAPK的激活有轻微抑制作用。综上所述，这些结果表明ERK和p38 MAPK途径均参与LPS诱导的中性粒细胞中COX-2的表达和PGE2的产生，并且IL-10和IL-4通过下调p38 MAPK的激活来抑制中性粒细胞前列腺素的合成。
