scholarly journals Insulinotropic Hormone Glucagon-Like Peptide 1 (GLP-1) Activation of Insulin Gene Promoter Inhibited by p38 Mitogen-Activated Protein Kinase*

Endocrinology ◽  
2001 ◽  
Vol 142 (3) ◽  
pp. 1179-1187 ◽  
Author(s):  
Daniel M. Kemp ◽  
Joel F. Habener
Keyword(s):  
P38 Mapk ◽  
Promoter Activity ◽  
Gene Promoter ◽  
Insulin Gene ◽  
Mitogen Activated Protein Kinase ◽  
Signaling Mechanism ◽  
Mitogen Activated Protein ◽  
Glucagon Like Peptide ◽  
Glucagon Like Peptide 1 ◽  
Sb 203580

Abstract The insulin gene promoter contains many transcriptional response elements that predispose the gene to a wide range of regulatory signals. Glucagon-like peptide 1 (GLP-1) stimulates insulin gene transcription by intracellular second messenger cascades leading to direct transcription factor activation or to the up-regulation of insulin promoter specific transcription factors. In these studies, we have identified a novel regulatory signaling mechanism acting on the rat insulin 1 promoter (rINS1) in the INS-1 β-cell line. In the presence of stimulatory concentrations of GLP-1 (0.1–100 nm) on rINS1 activity, inhibition of p38 mitogen-activated protein kinase (p38 MAPK) using SB 203580 resulted in a marked increase in promoter activity (maximum 3-fold) over GLP-1 alone, as determined by rINS1 promoter-luciferase reporter gene expression. This effect was revealed to be mediated via the cAMP response element (CRE) of rINS1, because site directed mutagenesis of the CRE motif in rINS1 abolished the increased response to SB 203580. Furthermore, inhibition of p38 MAPK uncovered a similar, more pronounced, response in the expression of a generic CRE promoter driven reporter gene. Time course dose-response studies indicate that the p38 MAPK induced inhibitory response may involve expression of immediate early genes (IEGs); maximum repression of rINS1 activity occurred after 4 h of treatment, comparable with regulatory responses by IEGs. In conclusion, these results demonstrate a novel signaling mechanism whereby p38 MAPK represses rINS1 promoter activity in response to GLP-1, suggesting the involvement of a robust regulatory control by p38 MAPK in insulin gene expression. The relevance of this mechanism may be most apparent during periods of cellular stress in which p38 MAPK activity is stimulated. In this regard, reduced insulin expression levels caused by chronic hyperglycemia (glucotoxicity) and/or hyperlipidemia (lipotoxicity) may be a direct consequence of this mechanism.

p38 mitogen-activated protein kinase inhibits calcium-dependent chloride secretion in T84 colonic epithelial cells

2003 ◽  
Vol 284 (2) ◽  
pp. C339-C348 ◽  
Author(s):  
Stephen J. Keely ◽  
Kim E. Barrett
Keyword(s):  
Protein Kinase ◽  
Epithelial Cells ◽  
Signaling Pathway ◽  
P38 Mapk ◽  
Mitogen Activated Protein Kinase ◽  
Muscarinic Agonist ◽  
Colonic Epithelial Cells ◽  
Mitogen Activated Protein ◽  
Intracellular Ca ◽  
Sb 203580

We have previously shown that Ca2+-dependent Cl−secretion across intestinal epithelial cells is limited by a signaling pathway involving transactivation of the epidermal growth factor receptor (EGFR) and activation of ERK mitogen-activated protein kinase (MAPK). Here, we have investigated a possible role for p38 MAPK in regulation of Ca2+-dependent Cl− secretion. Western blot analysis of T84 colonic epithelial cells revealed that the muscarinic agonist carbachol (CCh; 100 μM) stimulated phosphorylation and activation of p38 MAPK. The p38 inhibitor SB-203580 (10 μM) potentiated and prolonged short-circuit current ( I sc) responses to CCh across voltage-clamped T84 cells to 157.4 ± 6.9% of those in control cells ( n = 21; P < 0.001). CCh-induced p38 phosphorylation was attenuated by the EGFR inhibitor tyrphostin AG-1478 (0.1 nM–10 μM) and by the Src family kinase inhibitor PP2 (20 nM–2 μM). The effects of CCh on p38 phosphorylation were mimicked by thapsigargin (TG; 2 μM), which specifically elevates intracellular Ca2+, and were abolished by the Ca2+ chelator BAPTA-AM (20 μM), implying a role for intracellular Ca2+ in mediating p38 activation. SB-203580 (10 μM) potentiated I sc responses to TG to 172.4 ± 18.1% of those in control cells ( n= 18; P < 0.001). When cells were pretreated with SB-203580 and PD-98059 to simultaneously inhibit p38 and ERK MAPKs, respectively, I sc responses to TG and CCh were significantly greater than those observed with either inhibitor alone. We conclude that Ca2+-dependent agonists stimulate p38 MAPK in T84 cells by a mechanism involving intracellular Ca2+, Src family kinases, and the EGFR. CCh-stimulated p38 activation constitutes a similar, but distinct and complementary, antisecretory signaling pathway to that of ERK MAPK.

Hyperosmotic and thermal stresses activate p38-MAPK in the perfused amphibian heart

2002 ◽  
Vol 205 (4) ◽  
pp. 443-454 ◽  
Author(s):  
Ioanna-Katerina S. Aggeli ◽  
Catherine Gaitanaki ◽  
Antigone Lazou ◽  
Isidoros Beis
Keyword(s):  
P38 Mapk ◽  
Thermal Stresses ◽  
Final Concentration ◽  
Mitogen Activated Protein Kinase ◽  
Mitogen Activated Protein ◽  
Immunohistochemical Studies ◽  
Kinase Phosphorylation ◽  
Rapid Activation ◽  
Amphibian Heart ◽  
Sb 203580

SUMMARY We assessed the activation of p38-MAPK (mitogen-activated protein kinase) by osmotic and thermal stresses in the isolated perfused amphibian (Rana ridibunda) heart. Hyperosmotic stress induced the rapid activation of the kinase. In particular, in the presence of 0.5 mol l–1 sorbitol, p38-MAPK was maximally phosphorylated (by approximately twelvefold) at 15 min, while excess of NaCl (206 mmol l–1 final concentration) or KCl (16 mmol l–1 final concentration) stimulated a less potent activation, maximised (by approximately eightfold and fourfold) within 2 min and 30 s, respectively, relative to control values. The effect of all three compounds examined was reversible, since the kinase phosphorylation levels decreased upon reperfusion of the heart with normal bicarbonate-buffered saline. Conversely, hypotonicity did not induce any p38-MAPK activation. Furthermore, both hypothermia and hyperthermia induced considerable phosphorylation of the kinase, by four- and 7.5-fold, respectively, relative to control values. Immunohistochemical studies elucidated the localisation pattern of phospho-p38-MAPK and also revealed enhanced atrial natriuretic peptide (ANP) immunoreactivity in osmotically stressed hearts. Interestingly, SB 203580 (1 μmol l–1) not only completely blocked the activation of p38-MAPK by all these interventions, but also abolished the enhanced ANP immunoreactivity induced by 0.5 mol l–1 sorbitol. These findings indicate the possible involvement of ANP in the mechanisms regulating responses under such stressful conditions.

Role of p38 mitogen-activated protein kinase pathway in estrogen-mediated cardioprotection following trauma-hemorrhage

2007 ◽  
Vol 292 (6) ◽  
pp. H2982-H2987 ◽  
Author(s):  
Jun-Te Hsu ◽  
Ya-Ching Hsieh ◽  
Wen Hong Kan ◽  
Jian Guo Chen ◽  
Mashkoor A. Choudhry ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Cardiac Function ◽  
P38 Mapk ◽  
Mitogen Activated Protein Kinase ◽  
Male Rats ◽  
Mitogen Activated Protein ◽  
Salutary Effect ◽  
The Stability ◽  
Shock Proteins ◽  
Sb 203580

p38 mitogen-activated protein kinase (MAPK) activates a number of heat shock proteins (HSPs), including HSP27 and αB-crystallin, in response to stress. Activation of HSP27 or αB-crystallin is known to protect organs/cells by increasing the stability of actin microfilaments. Although our previous studies showed that 17β-estradiol (E2) improves cardiovascular function after trauma-hemorrhage, whether the salutary effects of E2 under those conditions are mediated via p38 MAPK remains unknown. Male rats (275–325 g body wt) were subjected to soft tissue trauma and hemorrhage (35–40 mmHg mean blood pressure for ∼90 min) followed by fluid resuscitation. At the onset of resuscitation, rats were injected intravenously with vehicle, E2 (1 mg/kg body wt), E2 + the p38 MAPK inhibitor SB-203580 (2 mg/kg body wt), or SB-203580 alone, and various parameters were measured 2 h thereafter. Cardiac functions that were depressed after trauma-hemorrhage were returned to normal levels by E2 administration, and phosphorylation of cardiac p38 MAPK, HSP27, and αB-crystallin was increased. The E2-mediated improvement of cardiac function and increase in p38 MAPK, HSP27, and αB-crystallin phosphorylation were abolished with coadministration of SB-203580. These results suggest that the salutary effect of E2 on cardiac function after trauma-hemorrhage is in part mediated via upregulation of p38 MAPK and subsequent phosphorylation of HSP27 and αB-crystallin.

Downregulation of human endothelial nitric oxide synthase promoter activity by p38 mitogen-activated protein kinase activation

2006 ◽  
Vol 84 (5) ◽  
pp. 780-789 ◽  
Author(s):  
Feiyue Xing ◽  
Yong Jiang ◽  
Jing Liu ◽  
Kesen Zhao ◽  
Yongyan Mo ◽  
...  
Keyword(s):  
Signaling Pathway ◽  
P38 Mapk ◽  
Endothelial Nitric Oxide Synthase ◽  
Promoter Activity ◽  
Mapk Signaling ◽  
Mitogen Activated Protein Kinase ◽  
Enos Gene ◽  
Mitogen Activated Protein ◽  
Oxide Synthase ◽  
Endothelial Nitric Oxide

Human endothelial nitric oxide synthase (eNOS) plays a crucial role in maintaining blood pressure homeostasis and vascular integrity. eNOS gene expression may be upregulated by a signaling pathway, including PI-3Kγ → Jak2 → MEK1 → ERK1/2 → PP2A. It remains unclear whether other mitogen-activated protein kinase (MAPK) family members, such as JNK, p38 kinase, and ERK5/BMK1, also modulate eNOS gene expression. Our purpose, therefore, is to shed light on the effect of the p38 MAPK signaling pathway on the regulation of eNOS promoter activity. The results showed that a red fluorescent protein reporter gene vector containing the full length of the human eNOS promoter was first successfully constructed, expressing efficiently in ECV304 cells with the characteristics of real time observation. The wild-types of p38α, p38β, p38γ, and p38δ signal molecules all markedly downregulated promoter activity, which could be reversed by their negative mutants, including p38α (AF), p38β (AF), p38γ (AF), and p38δ (AF). Promoter activity was also significantly downregulated by MKK6b (E), an active mutant of an upstream kinase of p38 MAPK. The reduction in promoter activity by p38 MAPK could be blocked by treatment with a p38 MAPK specific inhibitor, SB203580. Moreover, the activation of endogenous p38 MAPK induced by lipopolysaccharide resulted in a prominent reduction in promoter activity. These findings strongly suggest that the activation of the p38 MAPK signaling pathway may be implicated in the downregulation of human eNOS promoter activity.

TGF-β1 stimulates HO-1 via the p38 mitogen-activated protein kinase in A549 pulmonary epithelial cells

2002 ◽  
Vol 283 (5) ◽  
pp. L1094-L1102 ◽  
Author(s):  
Wen Ning ◽  
Ruiping Song ◽  
Chaojun Li ◽  
Edward Park ◽  
Amir Mohsenin ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Epithelial Cells ◽  
Mrna Expression ◽  
P38 Mapk ◽  
Mapk Pathway ◽  
A549 Cells ◽  
Mitogen Activated Protein Kinase ◽  
P38 Mapk Pathway ◽  
Mitogen Activated Protein ◽  
Sb 203580

In lung injury and progressive lung diseases, the multifunctional cytokine transforming growth factor-β1 (TGF-β1) modulates inflammatory responses and wound repair. Heme oxygenase-1 (HO-1) is a stress-inducible protein that has been demonstrated to confer cytoprotection against oxidative injury and provide a vital function in maintaining tissue homeostasis. Here we report that TGF-β1 is a potent inducer of HO-1 and examined the signaling pathway by which TGF-β1 regulates HO-1 expression in human lung epithelial cells (A549). TGF-β1(1–5 ng/ml) treatment resulted in a marked time-dependent induction of HO-1 mRNA in A549 cells, followed by corresponding increases in HO-1 protein and HO enzymatic activity. Actinomycin D and cycloheximide inhibited TGF-β1-responsive HO-1 mRNA expression, indicating a requirement for transcription and de novo protein synthesis. Furthermore, TGF-β1 rapidly activated the p38 mitogen-activated protein kinase (p38 MAPK) pathway in A549 cells. A chemical inhibitor of p38 MAPK (SB-203580) abolished TGF-β1-inducible HO-1 mRNA expression. Both SB-203580 and expression of a dominant-negative mutant of p38 MAPK inhibited TGF-β1-induced ho-1 gene activation, as assayed by luciferase activity of an ho-1enhancer/luciferase fusion construct (pMHO1luc-33+SX2). These studies demonstrate the critical intermediacy of the p38 MAPK pathway in the regulation of HO-1 expression by TGF-β1.

Thrombin stimulates dissociation and induction of HSP27 via p38 MAPK in vascular smooth muscle cells

2002 ◽  
Vol 283 (3) ◽  
pp. H941-H948 ◽  
Author(s):  
Kouseki Hirade ◽  
Osamu Kozawa ◽  
Kumiko Tanabe ◽  
Masayuki Niwa ◽  
Hiroyuki Matsuno ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
P38 Mapk ◽  
Mrna Level ◽  
Muscle Cells ◽  
Mitogen Activated Protein Kinase ◽  
Aortic Smooth Muscle ◽  
Mitogen Activated Protein ◽  
Shock Proteins ◽  
Sb 203580

We investigated the effects of thrombin on the induction of heat shock proteins (HSP) 70 and 27, and the mechanism behind the induction in aortic smooth muscle A10 cells. Thrombin increased the level of HSP27 but had little effect on the level of HSP70. Thrombin stimulated the accumulation of HSP27 dose dependently between 0.01 and 1 U/ml and cycloheximide reduced the accumulation. Thrombin stimulated an increase in the level of HSP27 mRNA and actinomycin D suppressed the thrombin-increased mRNA level. Thrombin induced the phosphorylation of p38 mitogen-activated protein kinase (MAPK). The HSP27 accumulation by thrombin was reduced by SB-203580 and PD-169316 but not by SB-202474. SB-203580 and PD-169316 suppressed the thrombin-induced phosphorylation of p38 MAPK. SB-203580 reduced the thrombin-increased level of HSP27 mRNA. Dissociation of the aggregated HSP27 to the dissociated HSP27 was induced by thrombin. Dissociation was inhibited by SB-203580. Thrombin induced the phosphorylation of HSP27 and the phosphorylation was suppressed by SB-203580. These results indicate that thrombin stimulates not only the dissociation of HSP27 but also the induction of HSP27 via p38 MAPK activation in aortic smooth muscle cells.

Mitogen-activated protein kinases regulate COX-2 and mucosal recovery in ischemic-injured porcine ileum

2004 ◽  
Vol 286 (6) ◽  
pp. G906-G913 ◽  
Author(s):  
Donnie E. Shifflett ◽  
Samuel L. Jones ◽  
Adam J. Moeser ◽  
Anthony T. Blikslager
Keyword(s):  
P38 Mapk ◽  
Barrier Function ◽  
Mapk Signaling ◽  
Mitogen Activated Protein Kinase ◽  
Prostaglandin E ◽  
Mapk Pathways ◽  
Mucosal Barrier Function ◽  
Mitogen Activated Protein ◽  
Cox 2 ◽  
Sb 203580

Mitogen-activated protein kinase (MAPK) pathways transduce signals from a diverse array of extracellular stimuli. The three primary MAPK-signaling pathways are the extracellular regulated kinases (ERK1/2), p38 MAPK, and c-Jun NH2-terminal kinase (JNK). Previous research in our laboratory has shown that COX-2-elaborated prostanoids participate in recovery of mucosal barrier function in ischemic-injured porcine ileum. Because COX-2 expression is regulated in part by MAPKs, we postulated that MAPK pathways would play an integral role in recovery of injured mucosa. Porcine mucosa was subjected to 45 min of ischemia, after which tissues were mounted in Ussing chambers, and transepithelial electrical resistance (TER) was monitored as an index of recovery of barrier function. Treatment of tissues with the p38 MAPK inhibitor SB-203580 (0.1 mM) or the ERK1/2 inhibitor PD-98059 (0.1 mM) abolished recovery. Western blot analysis revealed that SB-203580 inhibited upregulation of COX-2 that was observed in untreated ischemic-injured mucosa, whereas PD-98059 had no effect on COX-2 expression. Inhibition of TER recovery by SB-203580 or PD-98059 was overcome by administration of exogenous prostaglandin E2 (1 μM). The JNK inhibitor SP-600125 (0.1 mM) significantly increased TER and resulted in COX-2 upregulation. COX-2 expression appears to be positively and negatively regulated by the p38 MAPK and the JNK pathways, respectively. Alternatively, ERK1/2 appear to be involved in COX-2-independent reparative events that remain to be defined.

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