scholarly journals Coordinate Regulation of IκB Kinases by Mitogen-Activated Protein Kinase Kinase Kinase 1 and NF-κB-Inducing Kinase

1998 ◽  
Vol 18 (12) ◽  
pp. 7336-7343 ◽  
Author(s):  
Shino Nemoto ◽  
Joseph A. DiDonato ◽  
Anning Lin

ABSTRACT IκB kinases (IKKα and IKKβ) are key components of the IKK complex that mediates activation of the transcription factor NF-κB in response to extracellular stimuli such as inflammatory cytokines, viral and bacterial infection, and UV irradiation. Although NF-κB-inducing kinase (NIK) interacts with and activates the IKKs, the upstream kinases for the IKKs still remain obscure. We identified mitogen-activated protein kinase kinase kinase 1 (MEKK1) as an immediate upstream kinase of the IKK complex. MEKK1 is activated by tumor necrosis factor alpha (TNF-α) and interleukin-1 and can potentiate the stimulatory effect of TNF-α on IKK and NF-κB activation. The dominant negative mutant of MEKK1, on the other hand, partially blocks activation of IKK by TNF-α. MEKK1 interacts with and stimulates the activities of both IKKα and IKKβ in transfected HeLa and COS-1 cells and directly phosphorylates the IKKs in vitro. Furthermore, MEKK1 appears to act in parallel to NIK, leading to synergistic activation of the IKK complex. The formation of the MEKK1-IKK complex versus the NIK-IKK complex may provide a molecular basis for regulation of the IKK complex by various extracellular signals.

2001 ◽  
Vol 281 (6) ◽  
pp. G1405-G1412 ◽  
Author(s):  
T. Suzuki ◽  
E. Grand ◽  
C. Bowman ◽  
J. L. Merchant ◽  
A. Todisco ◽  
...  

Helicobacter pyloriand proinflammatory cytokines have a direct stimulatory effect on gastrin release from isolated G cells, but little is known about the mechanism by which these factors regulate gastrin gene expression. We explored whether tumor necrosis factor (TNF)-α and interleukin (IL)-1 directly regulate gastrin gene expression and, if so, by what mechanism. TNF-α and IL-1 significantly increased gastrin mRNA in canine G cells to 181 ± 18% and 187 ± 28% of control, respectively, after 24 h of treatment. TNF-α and IL-1 stimulated gastrin promoter activity to a maximal level of 285 ± 12% and 415 ± 26% of control. PD-98059 (a mitogen-activated protein kinase kinase inhibitor), SB-202190 (a p38 kinase inhibitor), and GF-109203 (a protein kinase C inhibitor) inhibited the stimulatory action of both cytokines on the gastrin promoter. In conclusion, both cytokines can directly regulate gastrin gene expression via a mitogen-activated protein kinase- and protein kinase C-dependent mechanism. These data suggest that TNF-α and IL-1 may play a direct role in Helicobacter pylori-induced hypergastrinemia.


2019 ◽  
Vol 31 (10) ◽  
pp. 1616
Author(s):  
Yu Lian ◽  
Yu Hu ◽  
Lu Gan ◽  
Yuan-Nan Huo ◽  
Hong-Yan Luo ◽  
...  

As an important gram-negative bacterial outer membrane component, lipopolysaccharide (LPS) plays an important role in bacterial-induced endometritis in sows. However, how LPS induces endometritis is unclear. We stimulated sow endometrial epithelial cells (EECs) with LPS and detected cell viability and tumour necrosis factor-α (TNF-α) and interleukin-1 (IL-1) secretion. LPS affected EEC viability and TNF-α and IL-1 secretion in a dose-dependent manner. LPS induced differential expression in 10 of 393 miRNAs in the EECs (downregulated, nine; upregulated, one). MicroRNA (miRNA) high-throughput sequencing of the LPS-induced EECs plus bioinformatics analysis and the dual-luciferase reporter system revealed a novel miRNA target gene: mitogen-activated protein kinase kinase kinase 14 (MAP3K14). Ssc-novel-miR-106-5p mimic, inhibitor and the nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor, alpha (IκBα) phosphorylation inhibitor Bay11–7085 were used to detect EEC nuclear factor-κB phosphorylation levels (p-NF-κB) and TNF-α and IL-1 secretion. MiR-106-5p mimic downregulated MAP3K14 mRNA and protein expression levels, inhibited p-NF-κB levels and decreased IL-1 and TNF-α secretion, whereas miR-106-5p inhibitor had the opposite effect. Bay11–7085 inhibited p-NF-κB expression and TNF-α and IL-1 secretion. These results suggest that LPS downregulates ssc-novel-miR-106-5p expression in sow EECs to increase MAP3K14 expression, which increases p-NF-κB to promote IL-1 and TNF-α secretion.


2010 ◽  
Vol 104 (7) ◽  
pp. 957-964 ◽  
Author(s):  
Jong-Eun Kim ◽  
Joe Eun Son ◽  
Sung Keun Jung ◽  
Nam Joo Kang ◽  
Chang Yong Lee ◽  
...  

Cocoa polyphenols have antioxidant and anti-inflammatory effects. TNF-α is a pro-inflammatory cytokine that has a vital role in the pathogenesis of inflammatory diseases such as cancer and psoriasis. Vascular endothelial growth factor (VEGF) expression is associated with tumorigenesis, CVD, rheumatoid arthritis and psoriasis. We tested whether cocoa polyphenol extract (CPE) inhibited TNF-α-induced VEGF expression in promotion-sensitive JB6 mouse epidermal cells. CPE significantly inhibited TNF-α-induced up-regulation of VEGF via reducing TNF-α-induced activation of the nuclear transcription factors activator protein-1 (AP-1) and NF-κB, which are key regulators of VEGF expression. CPE also inhibited TNF-α-induced phosphorylation of protein kinase B (Akt) and extracellular signal-regulated kinase. CPE blocked activation of their downstream kinases, p70 kDa ribosomal protein S6 kinase and p90 kDa ribosomal protein S6 kinase. CPE suppressed phosphoinositide 3-kinase (PI3K) activity via binding PI3K directly. CPE did not affect TNF-α-induced phosphorylation of mitogen-activated protein kinase kinase-1 (MEK1) but suppressed TNF-α-induced MEK1 activity. Collectively, these results indicate that CPE reduced TNF-α-induced up-regulation of VEGF by directly inhibiting PI3K and MEK1 activities, which may contribute to its chemopreventive potential.


2002 ◽  
Vol 22 (16) ◽  
pp. 5962-5974 ◽  
Author(s):  
Lawrence P. Kane ◽  
Marianne N. Mollenauer ◽  
Zheng Xu ◽  
Christoph W. Turck ◽  
Arthur Weiss

ABSTRACT The Akt (or protein kinase B) and Cot (or Tpl-2) serine/threonine kinases are associated with cellular transformation. These kinases have also been implicated in the induction of NF-κB-dependent transcription. As a member of the mitogen-activated protein kinase kinase kinase (MAP3K) family, Cot can also activate MAP kinase signaling pathways that target AP-1 and NFAT family transcription factors. Here we show that Akt and Cot physically associate and functionally cooperate. Akt appears to function upstream of Cot, as Akt can enhance Cot induction of NF-κB-dependent transcription, and dominant-negative Cot blocks the activation of this element by Akt. Furthermore, deletion analysis shows that binding to Akt is critical for Cot function. The regulation of NF-κB-dependent transcription by Cot requires Akt-dependent phosphorylation of serine 400 (S400), near the carboxy terminus of Cot. However, phosphorylation at this site is not required for Cot kinase activity or AP-1 induction, suggesting it specifically regulates Cot effector function at the level of the NF-κB pathway. Mutation of S400 in Cot does indeed abolish its ability to activate IκB-kinase (IKK) complexes, but paradoxically it allows for increased Cot association with the IKK complex. This mutated form of Cot also acts as a dominant negative for T-cell antigen receptor/CD28- or Akt/phorbol myristate acetate-induced NF-κB induction, while having relatively little effect on tumor necrosis factor induction of NF-κB. These findings suggest that the activation of different signaling pathways by MAP3Ks may be regulated separately and may provide evidence for how such discrimination by one member of this kinase family occurs.


2000 ◽  
Vol 20 (4) ◽  
pp. 1278-1290 ◽  
Author(s):  
Maryam Zamanian-Daryoush ◽  
Trine H. Mogensen ◽  
Joseph A. DiDonato ◽  
Bryan R. G. Williams

ABSTRACT The interferon (IFN)-inducible double-stranded-RNA (dsRNA)-activated serine-threonine protein kinase (PKR) is a major mediator of the antiviral and antiproliferative activities of IFNs. PKR has been implicated in different stress-induced signaling pathways including dsRNA signaling to nuclear factor kappa B (NF-κB). The mechanism by which PKR mediates activation of NF-κB is unknown. Here we show that in response to poly(rI) · poly(rC) (pIC), PKR activates IκB kinase (IKK), leading to the degradation of the inhibitors IκBα and IκBβ and the concomitant release of NF-κB. The results of kinetic studies revealed that pIC induced a slow and prolonged activation of IKK, which was preceded by PKR activation. In PKR null cell lines, pIC failed to stimulate IKK activity compared to cells from an isogenic background wild type for PKR in accord with the inability of PKR null cells to induce NF-κB in response to pIC. Moreover, PKR was required to establish a sustained response to tumor necrosis factor alpha (TNF-α) and to potentiate activation of NF-κB by cotreatment with TNF-α and IFN-γ. By coimmunoprecipitation, PKR was shown to be physically associated with the IKK complex. Transient expression of a dominant negative mutant of IKKβ or the NF-κB-inducing kinase (NIK) inhibited pIC-induced gene expression from an NF-κB-dependent reporter construct. Taken together, these results demonstrate that PKR-dependent dsRNA induction of NF-κB is mediated by NIK and IKK activation.


2013 ◽  
Vol 20 (9) ◽  
pp. 1396-1404 ◽  
Author(s):  
Laura Brudecki ◽  
Donald A. Ferguson ◽  
Charles E. McCall ◽  
Mohamed El Gazzar

ABSTRACTAutotoxic production of proinflammatory mediators during early sepsis induces excessive inflammation, and their later suppression may limit the immune response. We previously reported that sepsis differentially represses transcription and translation of tumor necrosis factor alpha (TNF-α) and interleukin 1β (IL-1β) to reprogram sepsis inflammation. This switch is gene specific and plays a crucial role in the clinically relevant syndrome of endotoxin adaptation/tolerance, multiorgan failure, and poor sepsis outcome. To further define the mechanisms responsible for translation disruption that follows inflammation induction, we used THP-1 human promonocytes as a model of Toll-like receptor 4 (TLR4) responses found in sepsis. We showed that phosphorylation-dependent activation of p38 mitogen-activated protein kinase (MAPK) and translation disruption of TNF-α and IL-6 follow increased MAPK phosphatase 1 (MKP-1) expression and that MKP-1 knockdown rephosphorylates p38 and restores the capacity to translate TNF-α and IL-6 mRNAs. We also observed that the RNA-binding protein motif 4 (RBM4), a p38 MAPK target, accumulates in an unphosphorylated form in the cytosol in endotoxin-adapted cells, suggesting that dephosphorylated RBM4 may function as a translational repressor. Moreover, MKP-1 knockdown promotes RBM4 phosphorylation, blocks its transfer from the nucleus to the cytosol, and reverses translation repression. We also found that microRNA 146a (miR-146a) knockdown prevents and miR-146a transfection induces MKP-1 expression, which lead to increases or decreases in TNF-α and IL-6 translation, respectively. We conclude that a TLR4-, miR-146a-, p38 MAPK-, and MKP-1-dependent autoregulatory pathway regulates the translation of proinflammatory genes during the acute inflammatory response by spatially and temporally modifying the phosphorylation state of RBM4 translational repressor protein.


1998 ◽  
Vol 333 (1) ◽  
pp. 11-15 ◽  
Author(s):  
Ana CUENDA ◽  
Donna S. DOROW

Overexpression of the protein kinases mixed-lineage kinase-2 (MLK2) or mitogen-activated protein kinase (MAPK) kinase kinase-1 (MEKK1) is known to trigger the activation of stress-activated protein kinase (SAPK1)/c-Jun N-terminal kinase (JNK). Here we demonstrate that MLK2 activates SAPK kinase-1 (SKK1)/MAPK kinase 4 (MKK4) and SKK4/MKK7, the two known direct activators of SAPK1/JNK (both in transfection studies and in vitro). In contrast, MEKK1 activates SKK1/MKK4 more efficiently than MLK2, but barely activates SKK4/MKK7. Since SKK4/MKK7 (but not SKK1/MKK4) is activated by interleukin-1 and tumour necrosis factor in several cells and tissues, we suggest that MEKK1 does not mediate the activation of SKK4/MKK7 and SAPK1/JNK induced by these pro-inflammatory cytokines. MLK2 and MEKK1 also activated SKK2/MKK3 and SKK3/MKK6, the direct upstream activators of SAPK2a/p38.


2001 ◽  
Vol 21 (19) ◽  
pp. 6461-6469 ◽  
Author(s):  
Kamal R. Mahtani ◽  
Matthew Brook ◽  
Jonathan L. E. Dean ◽  
Gareth Sully ◽  
Jeremy Saklatvala ◽  
...  

ABSTRACT Signal transduction pathways regulate gene expression in part by modulating the stability of specific mRNAs. For example, the mitogen-activated protein kinase (MAPK) p38 pathway mediates stabilization of tumor necrosis factor alpha (TNF-α) mRNA in myeloid cells stimulated with bacterial lipopolysaccharide (LPS). The zinc finger protein tristetraprolin (TTP) is expressed in response to LPS and regulates the stability of TNF-α mRNA. We show that stimulation of RAW264.7 mouse macrophages with LPS induces the binding of TTP to the TNF-α 3′ untranslated region. The p38 pathway is required for the induction of TNF-α RNA-binding activity and for the expression of TTP protein and mRNA. Following stimulation with LPS, TTP is expressed in multiple, differentially phosphorylated forms. We present evidence that phosphorylation of TTP is mediated by the p38-regulated kinase MAPKAPK2 (MAPK-activated protein kinase 2). Our findings demonstrate a direct link between a specific signal transduction pathway and a specific RNA-binding protein, both of which are known to regulate TNF-α gene expression at a posttranscriptional level.


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