scholarly journals Proteasome inhibitors up-regulate haem oxygenase-1 gene expression: requirement of p38 MAPK (mitogen-activated protein kinase) activation but not of NF-kappaB (nuclear factor kappaB) inhibition

2004 ◽  
Vol 379 (3) ◽  
pp. 587-593 ◽  
Author(s):  
Wen-Tung WU ◽  
Kwan-Hwa CHI ◽  
Feng-Ming HO ◽  
Wei-Chia TSAO ◽  
Wan-Wan LIN

Regulation of intracellular protein stability by the ubiquitin-dependent proteasome system plays a crucial role in cell function. HO-1 (haem oxygenase) is a stress response protein, which confers cytoprotection against oxidative injury and provides a vital function in maintaining tissue homoeostasis. In the present study, we found a novel action of proteasome inhibitors MG132 and MG262 on HO-1 induction, and characterized the underlying mechanisms. MG132 (≥0.1 µM) treatment resulted in a marked time- and concentration-dependent induction of the steady-state level of HO-1 mRNA in RAW264.7 macrophages, followed by a corresponding increase in HO-1 protein. Actinomycin D and cycloheximide inhibited MG132-responsive HO-1 protein expression, indicating a requirement for transcription and de novo protein synthesis. The involvement of signal pathways in MG132-induced HO-1 gene expression was examined using chemical inhibitors. Antioxidant N-acetylcysteine and SB203580, an antioxidant and inhibitor of p38 MAPK (mitogen-activated protein kinase), abolished MG132-inducible HO-1 expression. Furthermore, MG132 activated the p38 MAPK pathway. The half-life of HO-1 protein was prolonged by MG132, indicating that the upregulation of HO-1 by proteasome inhibitor is partially attributable to the inhibition of protein degradation. MG132 can ablate IκBα degradation and NF-κB (nuclear factor κB) activation induced by lipopolysaccharide, similar to the effect of another NF-κB inhibitor pyrrolidine dithiocarbamate. We found HO-1 upregulation by MG132 and pyrrolidine dithiocarbamate is unrelated to their inhibition of NF-κB, since leptomycin B, another NF-κB inhibitor, did not elicit similar induction of HO-1. Taken together, we found a novel effect of proteasome inhibitor on induction of HO-1 expression. This action is ascribed to the activation of the p38 MAPK pathway, but is not dependent on NF-κB inhibition.

2002 ◽  
Vol 76 (10) ◽  
pp. 4873-4885 ◽  
Author(s):  
Jiping Chen ◽  
Mark F. Stinski

ABSTRACT A series of recombinant viruses with either site-specific mutations or various deletions of the early UL4 promoter of human cytomegalovirus were used to determine the roles of regulatory elements and the effects of the mitogen-activated protein kinase (MAPK) pathways. Viral gene expression was regulated by upstream cis-acting sites and by basic promoter elements that respond to the MAPK signal transduction pathways. Inhibitors of either the mitogen-activated protein kinase/extracellular signal-regulated kinase (MAPK/ERK) pathway or the p38 MAPK pathway affected expression equally with either wild-type or mutant early UL4 promoters in the viral genome, indicating that the effects of the inhibitors are not exclusive for a single transcription factor. The minimal responsive element is the TATA box-containing early viral promoter.


2007 ◽  
Vol 293 (5) ◽  
pp. F1556-F1563 ◽  
Author(s):  
Frank Y. Ma ◽  
Greg H. Tesch ◽  
Richard A. Flavell ◽  
Roger J. Davis ◽  
David J. Nikolic-Paterson

Activation of the p38 mitogen-activated protein kinase (MAPK) pathway induces inflammation, apoptosis, and fibrosis. However, little is known of the contribution of the upstream kinases, MMK3 and MKK6, to activation of the p38 kinase in the kidney and consequent renal injury. This study investigated the contribution of MKK3 to p38 MAPK activation and renal injury in the obstructed kidney. Groups of eight wild-type (WT) or Mkk3−/− mice underwent unilateral ureteric obstruction (UUO) and were killed 3 or 7 days later. Western blotting showed a marked increase in phospho-p38 (p-p38) MAPK in UUO WT kidney. The same trend of increased p-p38 MAPK was seen in the UUO Mkk3−/− kidney, although the actual level of p-p38 MAPK was significantly reduced compared with WT, and this could not be entirely compensated for by the increase in MKK6 expression in the Mkk3−/− kidney. Apoptosis of tubular and interstitial cells in WT UUO mice was reduced by 50% in Mkk3−/− UUO mice. Furthermore, cultured Mkk3−/− tubular epithelial cells showed resistance to H2O2-induced apoptosis, suggesting a direct role for MKK3-p38 signaling in tubular apoptosis. Upregulation of MCP-1 mRNA levels and macrophage infiltration seen on day 3 in WT UUO mice was significantly reduced in Mkk3−/− mice, but this difference was not evident by day 7. The development of renal fibrosis in Mkk3−/− UUO mice was not different from that seen in WT UUO mice. In conclusion, these studies identify discrete roles for MKK3-p38 signaling in renal cell apoptosis and the early inflammatory response in the obstructed kidney.


2011 ◽  
Vol 300 (2) ◽  
pp. C375-C382 ◽  
Author(s):  
Chunhui Wang ◽  
Hua Xu ◽  
Huacong Chen ◽  
Jing Li ◽  
Bo Zhang ◽  
...  

Diarrhea is a common manifestation of gastrointestinal disorders. Diarrhea-induced losses of fluid and electrolyte could lead to dehydration and electrolyte imbalances, resulting in significant morbidity and mortality, especially in children living in developing countries. Somatostatin, a peptide hormone secreted by D-cells, plays an important role in regulating motility and intestinal Na+ absorption. Although octreotide, a somatostatin analog, is used to treat diarrhea, its mechanisms of action are unclear. Here we showed that octreotide increased brush-border membrane Na+/H+ exchanger 8 (NHE8) expression in the small intestine to the exclusion of other NHEs that participate in Na+ absorption. The same effect also occurred in human intestinal cells (Caco-2). We found that the increase of NHE8 expression by somatostatin required p38 mitogen-activated protein kinase (MAPK) activation. Furthermore, the somatostatin receptor SSTR2 antagonist CYN154806 could abolish somatostatin-induced NHE8 expression and p38 MAPK phosphorylation. Thus our data provided the first concrete evidence indicating that somatostatin stimulates intestinal Na+ absorption by increasing intestinal NHE8 expression through the SSTR2-p38 MAPK pathway.


Medicina ◽  
2021 ◽  
Vol 57 (4) ◽  
pp. 396
Author(s):  
Boya Nugraha ◽  
Renate Scheibe ◽  
Christoph Korallus ◽  
Matthias Gaestel ◽  
Christoph Gutenbrunner

Background and Objectives: The aetiology and pathomechanism of fibromyalgia syndrome 12 (FMS) as one of chronic pain syndromes still need to be further elucidated. Mitogen-activated protein kinase (MAPK) pathway has been proposed as a novel approach in pain management. Since the major symptom of fibromyalgia syndrome (FMS) patients is pain, it became of interest whether MAPK pathways, such as the stress-activated p38 MAPK/MK2 axis, are activated in FMS patients. Therefore, this study aimed at determining p38 MAPK/MK2 in FMS patients. Materials and Methods: Phosphorylation of MAPK-activated protein kinases 2 (MK2), a direct target of p38 MAPK, was measured in monocytes of FMS and healthy controls (HCs) to monitor the activity of this pathway. Results: The mean level of phosphorylated MK2 was fivefold higher in FMS patients as compared to HCs (p < 0.001). Subgroup analysis revealed that antidepressants did not influence the activity of MK2 in FMS patients. Conclusions: This result indicates that the p38/MK2 pathway could be involved in the pathomechanism of FMS, could act as a clinical marker for FMS, and could be a possible target for pain management in FMS patients.


2011 ◽  
Vol 300 (1) ◽  
pp. E103-E110 ◽  
Author(s):  
Xiaoban Xin ◽  
Lijun Zhou ◽  
Caleb M. Reyes ◽  
Feng Liu ◽  
Lily Q. Dong

The adaptor protein APPL1 mediates the stimulatory effect of adiponectin on p38 mitogen-activated protein kinase (MAPK) signaling, yet the underlying mechanism remains unclear. Here we show that, in C2C12 cells, overexpression or suppression of APPL1 enhanced or suppressed, respectively, adiponectin-stimulated p38 MAPK upstream kinase cascade, consisting of transforming growth factor-β-activated kinase 1 (TAK1) and mitogen-activated protein kinase kinase 3 (MKK3). In vitro affinity binding and coimmunoprecipitation experiments revealed that TAK1 and MKK3 bind to different regions of APPL1, suggesting that APPL1 functions as a scaffolding protein to facilitate adiponectin-stimulated p38 MAPK activation. Interestingly, suppressing APPL1 had no effect on TNFα-stimulated p38 MAPK phosphorylation in C2C12 myotubes, indicating that the stimulatory effect of APPL1 on p38 MAPK activation is selective. Taken together, our study demonstrated that the TAK1-MKK3 cascade mediates adiponectin signaling and uncovers a scaffolding role of APPL1 in regulating the TAK1-MKK3-p38 MAPK pathway, specifically in response to adiponectin stimulation.


2002 ◽  
Vol 22 (20) ◽  
pp. 6931-6945 ◽  
Author(s):  
Ole Morten Seternes ◽  
Bjarne Johansen ◽  
Beate Hegge ◽  
Mona Johannessen ◽  
Stephen M. Keyse ◽  
...  

ABSTRACT The p38 mitogen-activated protein kinase (MAPK) pathway is an important mediator of cellular responses to environmental stress. Targets of p38 include transcription factors, components of the translational machinery, and downstream serine/threonine kinases, including MAPK-activated protein kinase 5 (MK5). Here we have used enhanced green fluorescent protein fusion proteins to analyze the subcellular localization of MK5. Although this protein is predominantly nuclear in unstimulated cells, MK5 shuttles between the nucleus and the cytoplasm. Furthermore, we have shown that the C-terminal domain of MK5 contains both a functional nuclear localization signal (NLS) and a leucine-rich nuclear export signal (NES), indicating that the subcellular distribution of this kinase reflects the relative activities of these two signals. In support of this, we have shown that stress-induced activation of the p38 MAPK stimulates the chromosomal region maintenance 1 protein-dependent nuclear export of MK5. This is regulated by both binding of p38 MAPK to MK5, which masks the functional NLS, and stress-induced phosphorylation of MK5 by p38 MAPK, which either activates or unmasks the NES. These properties may define the ability of MK5 to differentially phosphorylate both nuclear and cytoplasmic targets or alternatively reflect a mechanism whereby signals initiated by activation of MK5 in the nucleus may be transmitted to the cytoplasm.


2008 ◽  
Vol 413 (3) ◽  
pp. 429-436 ◽  
Author(s):  
Yan Zeng ◽  
Heidi Sankala ◽  
Xiaoxiao Zhang ◽  
Paul R. Graves

Ago (Argonaute) proteins are essential effectors of RNA-mediated gene silencing. To explore potential regulatory mechanisms for Ago proteins, we examined the phosphorylation of human Ago2. We identified serine-387 as the major Ago2 phosphorylation site in vivo. Phosphorylation of Ago2 at serine-387 was significantly induced by treatment with sodium arsenite or anisomycin, and arsenite-induced phosphorylation was inhibited by a p38 MAPK (mitogen-activated protein kinase) inhibitor, but not by inhibitors of JNK (c-Jun N-terminal kinase) or MEK [MAPK/ERK (extracellular-signal-regulated kinase) kinase]. MAPKAPK2 (MAPK-activated protein kinase-2) phosphorylated bacterially expressed full-length human Ago2 at serine-387 in vitro, but not the S387A mutant. Finally, mutation of serine-387 to an alanine residue or treatment of cells with a p38 MAPK inhibitor reduced the localization of Ago2 to processing bodies. These results suggest a potential regulatory mechanism for RNA silencing acting through Ago2 serine-387 phosphorylation mediated by the p38 MAPK pathway.


2008 ◽  
Vol 412 (3) ◽  
pp. 435-445 ◽  
Author(s):  
Maja Jensen ◽  
Jane Palsgaard ◽  
Rehannah Borup ◽  
Pierre de Meyts ◽  
Lauge Schäffer

Single-chain peptides have been recently produced that display either mimetic or antagonistic properties against the insulin and IGF-1 (insulin-like growth factor 1) receptors. We have shown previously that the insulin mimetic peptide S597 leads to significant differences in receptor activation and initiation of downstream signalling cascades despite similar binding affinity and in vivo hypoglycaemic potency. It is still unclear how two ligands can initiate different signalling responses through the IR (insulin receptor). To investigate further how the activation of the IR by insulin and S597 differentially activates post-receptor signalling, we studied the gene expression profile in response to IR activation by either insulin or S597 using microarray technology. We found striking differences between the patterns induced by these two ligands. Most remarkable was that almost half of the genes differentially regulated by insulin and S597 were involved in cell proliferation and growth. Insulin either selectively regulated the expression of these genes or was a more potent regulator. Furthermore, we found that half of the differentially regulated genes interact with the genes involved with the MAPK (mitogen-activated protein kinase) pathway. These findings support our signalling results obtained previously and confirm that the main difference between S597 and insulin stimulation resides in the activation of the MAPK pathway. In conclusion, we show that insulin and S597 acting via the same receptor differentially affect gene expression in cells, resulting in a different mitogenicity of the two ligands, a finding which has critical therapeutic implications.


2001 ◽  
Vol 21 (19) ◽  
pp. 6515-6528 ◽  
Author(s):  
Kristin Baetz ◽  
Jason Moffat ◽  
Jennifer Haynes ◽  
Michael Chang ◽  
Brenda Andrews

ABSTRACT In Saccharomyces cerevisiae, the heterodimeric transcription factor SBF (for SCB binding factor) is composed of Swi4 and Swi6 and activates gene expression at the G1/S-phase transition of the mitotic cell cycle. Cell cycle commitment is associated not only with major alterations in gene expression but also with highly polarized cell growth; the mitogen-activated protein kinase (MAPK) Slt2 is required to maintain cell wall integrity during periods of polarized growth and cell wall stress. We describe experiments aimed at defining the regulatory pathway involving the cell cycle transcription factor SBF and Slt2-MAPK. Gene expression assays and chromatin immunoprecipitation experiments revealed Slt2-dependent recruitment of SBF to the promoters of the G1 cyclinsPCL1 and PCL2 after activation of the Slt2-MAPK pathway. We performed DNA microarray analysis and identified other genes whose expression was reduced in both SLT2and SWI4 deletion strains. Genes that are sensitive to both Slt2 and Swi4 appear to be uniquely regulated and reveal a role for Swi4, the DNA-binding component of SBF, which is independent of the regulatory subunit Swi6. Some of the Swi4- and Slt2-dependent genes do not require Swi6 for either their expression or for Swi4 localization to their promoters. Consistent with these results, we found a direct interaction between Swi4 and Slt2. Our results establish a new Slt2-dependent mode of Swi4 regulation and suggest roles for Swi4 beyond its prominent role in controlling cell cycle transcription.


Author(s):  
И.А. Щепеткин ◽  
О.П. Буданова ◽  
И.Ю. Малышев ◽  
Д.Н. Аточин

В обзоре представлены современные данные о механизмах инициации, регуляции и выполнении процесса апоптоза нейтрофилов с участием «рецепторов смерти», митохондрий, белков семейства Bcl-2, PI3-K (phosphatidylinositol 3-kinase), протеинкиназных каскадов p38 MAPK (mitogen-activated protein kinase), ERK (extracellular signal regulated kinase) и JNK (c-Jun N-terminal kinase), протеинкиназ А, В и С, сAMP, белков теплового шока, NF-kB (nuclear factor-kB), кальпаинов, каспаз и их ингибиторов, активных форм кислорода и других факторов. Предложена гипотетическая модель вовлечения апоптотических процессов в регуляцию дифференцировки и реактивности нейтрофилов. This review presented recent data on initiation, regulation, and execution of neutrophil apoptosis with participation of «death receptors», mitochondria, Bcl-2 family proteins, PI3-K (phosphatidylinositol 3-kinase), p38 MAPK (mitogen-activated protein kinase), ERK (extracellular signal regulated kinase) and JNK (c-Jun N-terminal kinase) cascades, protein kinases A, B and C, сAMP, heat shock proteins, NF-kB (nuclear factor-kB), calpains, caspases and theirs inhibitors, reactive oxygen species, and other factors. A speculative model of the apoptotic processes involvement in the regulation of neutrophil differentiation and reactivity was proposed.


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