Differentiation regulates interleukin-1β-induced cyclo-oxygenase-2 in human articular chondrocytes: role of p38 mitogen-activated protein kinase

2002 ◽  
Vol 362 (2) ◽  
pp. 367-373 ◽  
Author(s):  
Béatrice THOMAS ◽  
Sylvie THIRION ◽  
Lydie HUMBERT ◽  
Lujian TAN ◽  
Mary B. GOLDRING ◽  
...  

Chondrocyte dedifferentiation has been noted in osteoarthritic cartilage, but the contribution of this phenomenon is poorly understood. Interleukin (IL)-1β, the major pro-inflammatory cytokine found in osteoarthritic synovial fluid, induces the dedifferentiation of cultured articular chondrocytes, whereas E-series prostaglandins (PGE) are capable of inducing cell differentiation. Since PGE2 synthesis is up-regulated by IL-1β, we addressed the question of whether the state of chondrocyte differentiation may influence the production of IL-1-induced PGE2 by modulating cyclooxygenase (COX)-2 expression. Immortalized human articular chondrocytes, (tsT/AC62) cultured in monolayer after passage through alginate matrix (alg+) produced 5-fold greater amounts of PGE2 than continuous monolayer cultures (alg-) after stimulation with IL-1β. Moreover, IL-1β induced COX-2 expression at 0.01ng/ml in (alg+) cells, whereas a 100-fold higher dose of cytokine was necessary for stimulation in (alg-) cells. SB203580, a selective p38 mitogen-activated protein kinase (MAPK) inhibitor, completely abolished the IL-1β-induced COX-2 mRNA. Overexpression of p38 MAPK induces a COX-2 reporter, whereas overexpression of dominant negative p38 MAPK represses IL-1β-induced promoter expression. Interestingly, IL-1β-induced p38 MAPK activity was greatly enhanced in (alg+) compared with (alg-) cells. Our results suggest that differentiated articular chondrocytes are highly responsive to IL-1β and that p38 MAPK mediates this response by inducing COX-2 gene expression.

2000 ◽  
Vol 20 (12) ◽  
pp. 4265-4274 ◽  
Author(s):  
Marina Lasa ◽  
Kamal R. Mahtani ◽  
Andrew Finch ◽  
Gary Brewer ◽  
Jeremy Saklatvala ◽  
...  

ABSTRACT A tetracycline-regulated reporter system was used to investigate the regulation of cyclooxygenase 2 (Cox-2) mRNA stability by the mitogen-activated protein kinase (MAPK) p38 signaling cascade. The stable β-globin mRNA was rendered unstable by insertion of the 2,500-nucleotide Cox-2 3′ untranslated region (3′ UTR). The chimeric transcript was stabilized by a constitutively active form of MAPK kinase 6, an activator of p38. This stabilization was blocked by SB203580, an inhibitor of p38, and by two different dominant negative forms of MAPK-activated protein kinase 2 (MAPKAPK-2), a kinase lying downstream of p38. Constitutively active MAPKAPK-2 was also able to stabilize chimeric β-globin–Cox-2 transcripts. The MAPKAPK-2 substrate hsp27 may be involved in stabilization, as β-globin–Cox-2 transcripts were partially stabilized by phosphomimetic mutant forms of hsp27. A short (123-nucleotide) fragment of the Cox-2 3′ UTR was necessary and sufficient for the regulation of mRNA stability by the p38 cascade and interacted with a HeLa protein immunologically related to AU-rich element/poly(U) binding factor 1.


2007 ◽  
Vol 75 (9) ◽  
pp. 4472-4481 ◽  
Author(s):  
Junzo Hisatsune ◽  
Eiki Yamasaki ◽  
Masaaki Nakayama ◽  
Daisuke Shirasaka ◽  
Hisao Kurazono ◽  
...  

ABSTRACT Treatment of AZ-521 cells with Helicobacter pylori VacA increased cyclooxygenase 2 (COX-2) mRNA in a time- and dose-dependent manner. A p38 mitogen-activated protein kinase (MAPK) inhibitor, SB203580, blocked elevation of COX-2 mRNA levels, whereas PD98059, which blocks the Erk1/2 cascade, partially suppressed the increase. Consistent with involvement of p38 MAPK, VacA-induced accumulation of COX-2 mRNA was reduced in AZ-521 cells overexpressing a dominant-negative p38 MAPK (DN-p38). Phosphatidylinositol-specific phospholipase C, which inhibits VacA-induced p38 MAPK activation, blocked VacA-induced COX-2 expression. In parallel with COX-2 expression, VacA increased prostaglandin E2 (PGE2) production, which was inhibited by SB203580 and NS-398, a COX-2 inhibitor. VacA-induced PGE2 production was markedly attenuated in AZ-521 cells stably expressing DN-p38. VacA increased transcription of a COX-2 promoter reporter gene and activated a COX-2 promoter containing mutated NF-κB or NF-interleukin-6 sites but not a mutated cis-acting replication element (CRE) site, suggesting direct involvement of the activating transcription factor 2 (ATF-2)/CREB-binding region in VacA-induced COX-2 promoter activation. The reduction of ATF-2 expression in AZ-521 cells transformed with ATF-2-small interfering RNA duplexes resulted in suppression of COX-2 expression. Thus, VacA enhances PGE2 production by AZ-521 cells through induction of COX-2 expression via the p38 MAPK/ATF-2 cascade, leading to activation of the CRE site in the COX-2 promoter.


2007 ◽  
Vol 21 (12) ◽  
pp. 3071-3086 ◽  
Author(s):  
Djurdjica Coss ◽  
Cameron M. Hand ◽  
Karen K. J. Yaphockun ◽  
Heather A. Ely ◽  
Pamela L. Mellon

Abstract GnRH and activin independently and synergistically activate transcription of the FSH β-subunit gene, the subunit that provides specificity and is the limiting factor in the synthesis of the mature hormone. This synergistic interaction, as determined by two-way ANOVA, is specific for FSHβ and may, therefore, contribute to differential expression of the two gonadotropin hormones, which is critical for the reproductive cycle. We find that the cross-talk between the GnRH and activin signaling pathways occurs at the level of p38 MAPK, because the synergy is dependent on p38 MAPK activity, which is activated by GnRH, and activin cotreatment augments p38 activation by GnRH. Both the Smad and activator protein-1 binding sites on the FSHβ promoter are necessary and sufficient for synergy. After cotreatment, Smad 3 proteins are more highly phosphorylated on the activin-receptor signaling-dependent residues on the C terminus than with activin treatment alone, and c-Fos is more highly expressed than with GnRH treatment alone. Inhibition of p38 by either of two different inhibitors or a dominant-negative p38 kinase abrogates synergy on FSHβ expression, reduces c-Fos induction by GnRH, and prevents the further increase in c-Fos levels that occurs with cotreatment. Additionally, p38 is necessary for maximal Smad 3 C-terminal phosphorylation by activin treatment alone and for the further increase caused by cotreatment. Thus, p38 is the pivotal signaling molecule that integrates GnRH and activin interaction on the FSHβ promoter through higher induction of c-Fos and elevated Smad phosphorylation.


2001 ◽  
Vol 280 (5) ◽  
pp. H1970-H1981 ◽  
Author(s):  
Cherry Ballard-Croft ◽  
D. Jean White ◽  
David L. Maass ◽  
Dixie Peters Hybki ◽  
Jureta W. Horton

This study examined the hypothesis that burn trauma promotes cardiac myocyte secretion of inflammatory cytokines such as tumor necrosis factor (TNF)-α and produces cardiac contractile dysfunction via the p38 mitogen-activated protein kinase (MAPK) pathway. Sprague-Dawley rats were divided into four groups: 1) sham burn rats given anesthesia alone, 2) sham burn rats given the p38 MAPK inhibitor SB203580 (6 mg/kg po, 15 min; 6- and 22-h postburn), 3) rats given third-degree burns over 40% total body surface area and treated with vehicle (1 ml of saline) plus lactated Ringer solution for resuscitation (4 ml · kg−1 · percent burn−1), and 4) burn rats given injury and fluid resuscitation plus SB203580. Rats from each group were killed at several times postburn to examine p38 MAPK activity (by Western blot analysis or in vitro kinase assay); myocardial function and myocyte secretion of TNF-α were examined at 24-h postburn. These studies showed significant activation of p38 MAPK at 1-, 2-, and 4-h postburn compared with time-matched shams. Burn trauma impaired cardiac mechanical performance and promoted myocyte secretion of TNF-α. SB203580 inhibited p38 MAPK activity, reduced myocyte secretion of TNF-α, and prevented burn-mediated cardiac deficits. These data suggest p38 MAPK activation is one aspect of the signaling cascade that culminates in postburn secretion of TNF-α and contributes to postburn cardiac dysfunction.


2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Carol O’Callaghan ◽  
Liam J. Fanning ◽  
Orla P. Barry

p38δmitogen activated protein kinase (MAPK) is a unique stress responsive protein kinase. While the p38 MAPK family as a whole has been implicated in a wide variety of biological processes, a specific role for p38δMAPK in cellular signalling and its contribution to both physiological and pathological conditions are presently lacking. Recent emerging evidence, however, provides some insights into specific p38δMAPK signalling. Importantly, these studies have helped to highlight functional similarities as well as differences between p38δMAPK and the other members of the p38 MAPK family of kinases. In this review we discuss the current understanding of the molecular mechanisms underlying p38δMAPK activity. We outline a role for p38δMAPK in important cellular processes such as differentiation and apoptosis as well as pathological conditions such as neurodegenerative disorders, diabetes, and inflammatory disease. Interestingly, disparate roles for p38δMAPK in tumour development have also recently been reported. Thus, we consider evidence which characterises p38δMAPK as both a tumour promoter and a tumour suppressor. In summary, while our knowledge of p38δMAPK has progressed somewhat since its identification in 1997, our understanding of this particular isoform in many cellular processes still strikingly lags behind that of its counterparts.


2001 ◽  
Vol 21 (22) ◽  
pp. 7545-7557 ◽  
Author(s):  
Annette R. Khaled ◽  
Andrea N. Moor ◽  
Aiqun Li ◽  
Kyungjae Kim ◽  
Douglas K. Ferris ◽  
...  

ABSTRACT Trophic factor withdrawal induces cell death by mechanisms that are incompletely understood. Previously we reported that withdrawal of interleukin-7 (IL-7) or IL-3 produced a rapid intracellular alkalinization, disrupting mitochondrial metabolism and activating the death protein Bax. We now observe that this novel alkalinization pathway is mediated by the pH regulator NHE1, as shown by the requirement for sodium, blocking by pharmacological inhibitors or use of an NHE1-deficient cell line, and the altered phosphorylation of NHE1. Alkalinization also required the stress-activated p38 mitogen-activated protein kinase (MAPK). Inhibition of p38 MAPK activity with pharmacological inhibitors or expression of a dominant negative kinase prevented alkalinization. Activated p38 MAPK directly phosphorylated the C terminus of NHE1 within a 40-amino-acid region. Analysis by mass spectroscopy identified four phosphorylation sites on NHE1, Thr 717, Ser 722, Ser 725, and Ser 728. Thus, loss of trophic cytokine signaling induced the p38 MAPK pathway, which phosphorylated NHE1 at specific sites, inducing intracellular alkalinization.


2012 ◽  
Vol 40 (1) ◽  
pp. 79-84 ◽  
Author(s):  
Ivan del Barco Barrantes ◽  
Angel R. Nebreda

Cells from primary tumours need to go through several steps to become fully metastatic. During this process, cancer cells acquire the ability to invade, migrate across the surrounding tissue, enter into the circulation and colonize distant organs. In the present paper, we review recent progress in understanding how the p38 MAPK (mitogen-activated protein kinase) signalling pathway participates in the different steps of metastasis. Experimental evidence suggests that tumour cells need to modulate p38 MAPK activity levels to successfully metastasize.


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