Prostaglandin E2 downregulates TNF-α-induced production of matrix metalloproteinase-1 in HCS-2/8 chondrocytes by inhibiting Raf-1/MEK/ERK cascade through EP4 prostanoid receptor activation
Prostaglandin E2 downregulates TNF-α-induced production of matrix metalloproteinase-1 in HCS-2/8 chondrocytes by inhibiting Raf-1/MEK/ERK cascade through EP4 prostanoid receptor activation
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DOI：
10.1002/jcb.21099
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发表时间：
2007-02-15
影响因子：
4
通讯作者：
Shimizu, Katsuji
中科院分区：
文献类型：
--
作者：
Fushimi, Kazunari;Nakashima, Shigeru;Shimizu, Katsuji
基质金属蛋白酶-1（MMP-1，胶原酶-1）在退行性关节疾病的关节破坏过程中起着关键作用。我们已经研究了MMP-1的生产在人软骨细胞HCS-2/8细胞刺激肿瘤坏死因子-α（TNF-α）的调节。作为对TNF-α的响应，MMP-1被诱导并从HCS-2/8细胞中主动释放。MMP-1表达的诱导与ERK 1/2、MEK和Raf-1的激活相关，并且被MEK 1/2激活的选择性抑制剂U 0126有效地阻止。相比之下，SB 203580，一种选择性p38丝裂原活化蛋白激酶（MAPK）抑制剂，对TNF-α诱导的MMP-1释放没有影响。一种丝氨酸/苏氨酸激酶，Akt在TNF-α刺激的HCS-2/8细胞中未被激活。TNF-α刺激HCS-2/8细胞产生PGE（2）和MMP-1。外源性PGE（2）可有效抑制TNF-α诱导的MMP-1生成和ERK 1/2激活。PGE（2）的作用可被选择性EP 4受体激动剂ONO-AE 1 -329模拟，但不能被选择性EP 2受体激动剂布他前列素模拟。相反，通过选择性EP 4受体拮抗剂ONO-AE 3 -208阻断内源性产生的PGE（2）信号，增强TNF-α诱导的MMP-1产生。此外，通过外源添加的PGE（2）对MMP-1产生的抑制被ONO-AE 3 -208逆转。EP 4受体的激活导致cAMP介导的Raf-1在Ser 259（一个负调节位点）上的磷酸化，并阻断Raf-1/MEK/ERK级联的激活。综上所述，这些发现表明Raf-1/MEK/ERK信号通路在HCS-2/8细胞响应TNF-α产生MMP-1中起关键作用，并且产生的PGE（2）通过EP 4-PGE（2）受体激活阻断TNF-α诱导的Raf-1激活来下调MMP-1的表达。
Matrix metalloproteinase-1 (MMP-1, collagenase-1) plays a pivotal role in the process of joint destruction in degenerative joint diseases. We have examined the regulation of MMP-1 production in human chondrocytic HCS-2/8 cells stimulated by tumor necrosis factor-alpha (TNF-alpha). In response to TNF-alpha, MMP-1 is induced and actively released from HCS-2/8 cells. The induction of MMP-1 expression correlates with activation of ERK1/2, MEK, and Raf-1, and is potently prevented by U0126, a selective inhibitor of MEK1/2 activation. In contrast, SB203580, a selective p38 mitogen-activated protein kinases (MAPK) inhibitor, had no effects on TNF-alpha-induced MMP-1 release. A serine/threonine kinase, Akt was not activated in TNF-alpha-stimulated HCS-2/8 cells. TNF-alpha stimulated the production of PGE(2) in addition to MMP-1 in HCS-2/8 cells. Exogenously added PGE(2) potently inhibited TNF-alpha-induced both MMP-1 production and activation of ERK1/2. The effects of PGE(2) were mimicked by ONO-AE1-329, a selective EP4 receptor agonist but not by butaprost, a selective EP2 agonist. In contrast, blockade of endogenously produced PGE(2) signaling by ONO-AE3-208, a selective EP4 receptor antagonist, enhanced TNF-alpha-induced MMP-1 production. Furthermore, the suppression of MMP-l production by exogenously added PGE(2) was reversed by ONO-AE3-208. Activation of EP4 receptor resulted in cAMP-mediated phosphorylation of Raf-1 on Ser259, a negative regulatory site, and blocked activation of Raf-1/MEK/ERK cascade. Taken together, these findings indicate that Raf-1/MEK/ERK signaling pathway plays a crucial role in the production of MMP-1 in HCS-2/8 cells in response to TNF-alpha, and that the produced PGE(2) downregulates the expression of MMP-1 by blockage of TNF-alpha-induced Raf-1 activation through EP4-PGE(2) receptor activation.