Novel insights into the cellular mechanisms of the anti-inflammatory effects of NF-kappaB essential modulator binding domain peptides.
Novel insights into the cellular mechanisms of the anti-inflammatory effects of NF-kappaB essential modulator binding domain peptides.
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DOI：
10.1074/jbc.m109.099895
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发表时间：
2010-04-30
期刊：
影响因子：
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通讯作者：
Mbalaviele G
中科院分区：
文献类型：
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作者：
Baima ET;Guzova JA;Mathialagan S;Nagiec EE;Hardy MM;Song LR;Bonar SL;Weinberg RA;Selness SR;Woodard SS;Chrencik J;Hood WF;Schindler JF;Kishore N;Mbalaviele G
经典的核因子κB(NF-κB)信号通路受控于IκB激酶(IKK)复合体，该复合体由IKK-1、IKK-2和NF-κB基本调节器(NEMO)组成。这种复合体负责调节细胞的增殖、存活和分化。这一途径的失调与几种人类疾病有关，因此，它的抑制为治疗干预提供了一个令人兴奋的机会。NEMO结合域(NBD)在体外可抑制重组NEMO与IKK-2的结合。然而，还没有提供NBD多肽在生物系统中破坏这种结合的直接证据。利用细胞系统，我们对先前的观察进行了扩展，表明NBD多肽抑制炎症诱导的细胞因子的产生，但不抑制基础细胞因子的产生。我们报道，这些多肽导致IKK复合体释放IKK-2，并破坏细胞内Nemo-IKK-2的相互作用。我们证明，通过干扰NEMO-IKK-2相互作用，NbD多肽抑制了IKK-2的磷酸化，而不影响NF-κB途径IKK复合体上游的信号中间产物。此外，在TRAF6(肿瘤坏死因子受体相关因子6)激活的IKK复合体的无细胞系统中，我们发现这些肽抑制该复合体对下游底物的磷酸化能力，如p65和κBα的抑制物(IκBα)。因此，与NEMO作为支架调节IKK-2催化活性的观点一致，我们的发现为NBD肽在细胞中发挥抗炎作用的分子机制提供了新的见解。
The classical nuclear factor κB (NF-κB) signaling pathway is under the control of the IκB kinase (IKK) complex, which consists of IKK-1, IKK-2, and NF-κB essential modulator (NEMO). This complex is responsible for the regulation of cell proliferation, survival, and differentiation. Dysregulation of this pathway is associated with several human diseases, and as such, its inhibition offers an exciting opportunity for therapeutic intervention. NEMO binding domain (NBD) peptides inhibit the binding of recombinant NEMO to IKK-2 in vitro. However, direct evidence of disruption of this binding by NBD peptides in biological systems has not been provided. Using a cell system, we expanded on previous observations to show that NBD peptides inhibit inflammation-induced but not basal cytokine production. We report that these peptides cause the release of IKK-2 from an IKK complex and disrupt NEMO-IKK-2 interactions in cells. We demonstrate that by interfering with NEMO-IKK-2 interactions, NBD peptides inhibit IKK-2 phosphorylation, without affecting signaling intermediates upstream of the IKK complex of the NF-κB pathway. Furthermore, in a cell-free system of IKK complex activation by TRAF6 (TNF receptor-associated factor 6), we show that these peptides inhibit the ability of this complex to phosphorylate downstream substrates, such as p65 and inhibitor of κBα (IκBα). Thus, consistent with the notion that NEMO regulates IKK-2 catalytic activity by serving as a scaffold, appropriately positioning IKK-2 for activation by upstream kinase(s), our findings provide novel insights into the molecular mechanisms by which NBD peptides exert their anti-inflammatory effects in cells.