BK-induced cytosolic phospholipase A2 expression via sequential PKC-δ, p42/p44 MAPK, and NF-κB activation in rat brain astrocytes
BK-induced cytosolic phospholipase A2 expression via sequential PKC-δ, p42/p44 MAPK, and NF-κB activation in rat brain astrocytes
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DOI：
10.1002/jcp.20457
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发表时间：
2006-01-01
影响因子：
5.6
通讯作者：
Yang, CM
中科院分区：
文献类型：
--
作者：
Hsieh, HL;Wu, CY;Yang, CM
缓激肽（BK）是一种炎症介质，已被证明可诱导胞浆磷脂酶A（2）（cPLA（2））的表达，这与多种细胞类型的炎症反应有关。然而，BK诱导星形胶质细胞中cPLA 2表达的详细机制仍不清楚。RT-PCR和Western blotting分析显示BK诱导了cPLA 2 mRNA和蛋白的表达，Hoe 140抑制了cPLA 2的表达，提示132个BK受体参与了cPLA 2的表达，用抗B-2 BK受体抗体进行免疫荧光染色证实了这一点。BK诱导的cPLA 2表达和p42/p44 MAPK磷酸化被PD 98059减弱，表明MEK 1/2-p42/p44 MAPK参与这些反应。BK诱导的cPLA 2表达可能是由于NF-κ B易位入核所致，而Hoel 40、helenalin和PD 98059可抑制NF-κ B易位入核，提示NF-κ B参与了cPLA 2的表达。此外，BK诱导的cPLA 2表达被rottlerin减弱，表明PKC-δ可能参与这些反应。这一假设得到了PKC-δ显性阴性质粒转染显著减弱BK诱导的反应的支持。此外，BK刺激的PKC-6从胞浆到膜组分的易位被rottlerin抑制，但不被PD 98059抑制，表明PKC-δ可能是p42/p44 MAPK的上游组分。因此，BK诱导的p42/p44 MAPK磷酸化被rottlerin减弱，而不是helenalin。这些结果表明，在RBA-1细胞中，BK诱导的cPLA 2表达依次通过激活PKC-6、p42/p44 MAPK和NF-κ B介导。了解BK对星形胶质细胞cPLA 2表达的调控可能为脑损伤和炎症性疾病的治疗提供新的策略。J.细胞。206：246-254，2006。(c)2005 Wiley-Liss，Inc.
Bradykinin (BK), an inflammatory mediator, has been shown to induce cytosolic phospholipase A(2) (cPLA(2)) expression implicating in inflammatory responses in various cell types. However, the detailed mechanisms underlying BK-induced cPLA2 expression in astrocytes remain unclear. RT-PCR and Western blotting analysis showed that BK induced the expression of cPLA2 mRNA and protein, which was inhibited by Hoe140, suggesting the involvement of 132 BK receptors, confirmed by immunofluorescence staining using anti-B-2 BK receptor antibody. BK-induced cPLA2 expression and phosphorylation of p42/p44 MAPK was attenuated by PD98059, indicating the involvement of MEK 1/2-p42/p44 MAPK in these responses. BK-induced cPLA2 expression might be due to the translocation of NF-kappa B into nucleus which was inhibited by Hoel 40, helenalin, and PD98059, implying the involvement of NF-kappa B. Moreover, BK-induced cPLA2 expression was attenuated by rottlerin, suggesting that PKC-delta might be involved in these responses. This hypothesis was supported by the transfection with a dominant negative plasmid of PKC-delta significantly attenuated BK-induced response. In addition, BK-stimulated translocation of PKC-6 from cytosol to membrane fraction was inhibited by rottlerin but not by PD98059, indicating that PKC-delta might be an upstream component of p42/p44 MAPK. Accordingly, BK-induced phosphorylation of p42/p44 MAPK was attenuated by rottlerin but not by helenalin. These results suggest that in RBA-1 cells, BK-induced cPLA2 expression was sequentially mediated through activation of PKC-6, p42/p44 MAPK, and NF-kappa B. Understanding the regulation of cPLA2 expression induced by BK in astrocytes might provide a new therapeutic strategy of brain injury and inflammatory diseases. J. Cell. Physiol. 206: 246-254, 2006. (c) 2005 Wiley-Liss, Inc.