Involvement of the Erk-MAP kinase pathway in TNFα regulation of trabecular matrix metalloproteinases and TIMPs
Involvement of the Erk-MAP kinase pathway in TNFα regulation of trabecular matrix metalloproteinases and TIMPs
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DOI：
10.1167/iovs.01-1201
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发表时间：
2003-01-01
影响因子：
4.4
通讯作者：
Acott, TS
中科院分区：
文献类型：
--
作者：
Alexander, JP;Acott, TS
目的。 TNFα 是小梁网 (TM) 基质金属蛋白酶 (MMP) 和组织抑制剂 (TIMP) 的强调节剂表达。激光小梁成形术似乎依赖于这一过程来恢复正常的房水流出功能。因此，进行研究以确定细胞外信号调节激酶（Erk）-丝裂原激活蛋白（MAP）激酶信号转导途径是否参与其中。方法。用 TNFα 处理猪 TM 细胞，并通过酶谱法和 Western 免疫印迹测定评估 MMP 和 TIMP 的变化。 Erk 通路蛋白的磷酸特异性抗体用于评估 TNFα 治疗的反应。 Mek（激活 Erk 的激酶）和蛋白激酶 C (PKC) 亚型的抑制剂用于定义通路参与。结果。用TNFα处理增加了MMP-1、-3和-9以及TIMP-1，而MMP-2的表达不受影响并且TIMP-2的表达降低。 Erk 和 Mek 在 TNFα 处理后迅速磷酸化，c-Raf-1 显示出显着的带移。 Mek 的特异性抑制剂可阻断 MMP 和 TIMP 的 TNFα 诱导以及 Erk 的磷酸化。 PKC-mu 同工型抑制剂也可阻断 TNFα 的 MMP-TIMP 的作用，但不会影响 Erk 的磷酸化。结论。 TM 中 MAP 激酶通路的组成部分受到 TNFα 的显着影响，并且抑制 Erk 磷酸化会阻断 MMP 和 TIMP 表达的变化。 PKC mu（该转导过程中也是必需的）似乎并不位于信号级联中 Erk 的上游。对该通路和相关 TM 信号转导通路的操纵可能为开发改进的青光眼治疗提供目标。
PURPOSE. TNFalpha is a strong modulator expression of trabecular meshwork (TM) matrix metalloproteinase (MMP) and tissue inhibitor (TIMP). Laser trabeculoplasty appears to rely on this process to restore normal aqueous humor outflow facility. Thus, studies were conducted to determine whether the extracellular signal-regulated kinase (Erk)-mitogen-activated protein (MAP) kinase signal-transduction pathway is involved.METHODS. Porcine TM cells were treated with TNFalpha, and changes in MMPs and TIMPs were evaluated by zymography and Western immunoblot assay. Phosphospecific antibodies to proteins from the Erk pathway were used to evaluate responses to treatment with TNFalpha. Inhibitors of Mek, the kinase that activates Erk, and of protein kinase C (PKC) isoforms were used to define pathway involvement.RESULTS. Treatment with TNFalpha increased MMP-1, -3, and -9 and TIMP-1, whereas expression of MMP-2 was not affected and expression of TIMP-2 was decreased. Erk and Mek were rapidly phosphorylated after treatment with TNFalpha, and c-Raf-1 showed a significant bandshift. A specific inhibitor of Mek blocked the TNFalpha induction of the MMPs and TIMPs and the phosphorylation of Erk. An inhibitor of the PKC-mu isoform, which also blocks the effects of MMP-TIMP of TNFalpha, did not affect phosphorylation of Erk.CONCLUSIONS. The components of this MAP kinase pathway in the TM are dramatically affected by TNFalpha and inhibition of Erk's phosphorylation blocks the changes in MMP and TIMP expression. PKC mu, which is also required in this transduction process, does not appear to be upstream from Erk in the signaling cascade. Manipulation of this and related TM signal-transduction pathways may provide targets for developing improved glaucoma treatments.