Monocarboxylate Transporter-1 Is Required for Cell Death in Mouse Chondrocytic ATDC5 Cells Exposed to Interleukin-1β via Late Phase Activation of Nuclear Factor κB and Expression of Phagocyte-type NADPH Oxidase*
Monocarboxylate Transporter-1 Is Required for Cell Death in Mouse Chondrocytic ATDC5 Cells Exposed to Interleukin-1β via Late Phase Activation of Nuclear Factor κB and Expression of Phagocyte-type NADPH Oxidase*
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DOI：
10.1074/jbc.m111.221259
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发表时间：
2011-03
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影响因子：
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通讯作者：
K. Yoshimura;Y. Miyamoto;R. Yasuhara;Toshifumi Maruyama;T. Akiyama;A. Yamada;M. Takami;T. Suzawa;Shoko Tsunawaki;T. Tachikawa;Kazuyoshi Baba;R. Kamijo
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作者：
K. Yoshimura;Y. Miyamoto;R. Yasuhara;Toshifumi Maruyama;T. Akiyama;A. Yamada;M. Takami;T. Suzawa;Shoko Tsunawaki;T. Tachikawa;Kazuyoshi Baba;R. Kamijo
白细胞介素-1 β（IL-1β）以一氧化氮（NO）和活性氧（ROS）依赖的方式诱导软骨细胞死亡。在这项研究中，在IL-1β处理的小鼠软骨细胞ATDC 5细胞死亡前观察到乳酸产生增加。通过引入针对单羧酸转运蛋白-1（MCT-1）（一种分布在血浆和线粒体内膜中的乳酸转运蛋白）的siRNA，抑制了ATDC 5细胞中IL-1β诱导的细胞死亡。Mct-1敲低也阻止了IL-1β诱导的吞噬细胞型NADPH氧化酶（NOX-2）的表达，NOX-2是一种专门用于产生ROS的酶，而它对诱导型NO合酶没有影响。通过Nox-2 siRNA抑制IL-1β诱导的细胞死亡，表明NOX-2参与细胞死亡。Mct-1 siRNA对IL-1β作用后5 ~ 20 min κBα抑制因子（IκBα）的磷酸化和降解无影响。IL-1β作用12 h后，IκBα略有下降，36 h后下降最为明显，而p65/RelA在IL-1β作用12 ~ 48 h后激活。这些变化在Mct-1沉默的细胞中没有观察到。IκBα超阻遏物的强制表达以及IκB激酶抑制剂BAY 11-7082的处理抑制了NOX-2的表达。此外，Mct-1 siRNA降低了暴露于IL-1β 15 h后产生的ROS水平，而ROS清除剂N-乙酰半胱氨酸抑制了IκBα和Nox-2表达的晚期降解。这些结果表明，在暴露于IL-1β的ATDC 5细胞中，MCT-1以ROS依赖性方式通过NF-κB的晚期激活促进NOX-2表达。
Interleukin-1β (IL-1β) induces cell death in chondrocytes in a nitric oxide (NO)- and reactive oxygen species (ROS)-dependent manner. In this study, increased production of lactate was observed in IL-1β-treated mouse chondrocytic ATDC5 cells prior to the onset of their death. IL-1β-induced cell death in ATDC5 cells was suppressed by introducing an siRNA for monocarboxylate transporter-1 (MCT-1), a lactate transporter distributed in plasma and mitochondrial inner membranes. Mct-1 knockdown also prevented IL-1β-induced expression of phagocyte-type NADPH oxidase (NOX-2), an enzyme specialized for production of ROS, whereas it did not have an effect on inducible NO synthase. Suppression of IL-1β-induced cell death by Nox-2 siRNA indicated that NOX-2 is involved in cell death. Phosphorylation and degradation of inhibitor of κBα (IκBα) from 5 to 20 min after the addition of IL-1β was not affected by Mct-1 siRNA. In addition, IκBα was slightly decreased after 12 h of incubation with IL-1β, and the decrease was prominent after 36 h, whereas activation of p65/RelA was observed from 12 to 48 h after exposure to IL-1β. These changes were not seen in Mct-1-silenced cells. Forced expression of IκBα super repressor as well as treatment with the IκB kinase inhibitor BAY 11-7082 suppressed NOX-2 expression. Furthermore, Mct-1 siRNA lowered the level of ROS generated after 15-h exposure to IL-1β, whereas a ROS scavenger, N-acetylcysteine, suppressed both late phase degradation of IκBα and Nox-2 expression. These results suggest that MCT-1 contributes to NOX-2 expression via late phase activation of NF-κB in a ROS-dependent manner in ATDC5 cells exposed to IL-1β.