UNIPROT:P10145 - FACTA Search

Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Target Concepts:

Query: UNIPROT:P10145 (IL-8)
23,849 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Peroxisome proliferator-activated receptors (PPARs) are ligand-activated transcription factors that directly control numerous genes of lipid metabolism by binding to response elements in the promoter. It has recently been proposed that PPARgamma may also regulate genes for proinflammatory proteins, not through PPRE binding but by interaction with transcription factors AP-1, STAT, and NF-kappaB. Recent studies with cultured human monocytes, however, have failed to observe an inhibitory effect of PPARgamma agonists on induced expression of TNFalpha and IL-6, genes known to be controlled by AP-1, STAT, and NF-kappaB. In a similar fashion, we show here that PPARalpha (fenofibrate) or PPARgamma (rosiglitazone) agonists failed to modulate LPS-induced secretion of IL-8 in THP-1 cells. When we made parallel observations on another gene, matrix metalloproteinase 9 (MMP-9), we were surprised to find profound downregulation of LPS-induced secretion by both PPARalpha or PPARgamma agonists. These findings suggest that PPAR may regulate only a subset of the proinflammatory genes controlled by AP-1, STAT, and NF-kappaB. Effects of PPARs on MMP-9 may account for the beneficial effect of PPAR agonists in animal models of atherosclerosis.
...
PMID:Activation of PPARalpha or gamma reduces secretion of matrix metalloproteinase 9 but not interleukin 8 from human monocytic THP-1 cells. 1062 22

Peroxisome proliferator-activated (PPARs) are ligand-activated transcription factors belonging to the nuclear receptor family. PPARs function as regulators of lipid and lipoprotein metabolism and glucose homeostasis and influence cellular proliferation, differentiation and apoptosis. PPARalpha is highly expressed in tissues such as liver, muscle, kidney and heart, where it stimulates the beta-oxidative degradation of fatty acids. PPARgamma is predominantly expressed in intestine and adipose tissue. PPARgamma triggers adipocyte differentiation and promotes lipid storage. The hypolipidemic fibrates and the antidiabetic glitazones are synthetic ligands for PPARalpha and PPARgamma, respectively. Furthermore, fatty acids and eicosanoids are natural PPAR ligands: PPARalpha is activated by leukotriene B4, whereas prostaglandin J2 is a PPARgamma ligand. These observations suggested a potential role for PPARs not only in metabolic but also in inflammation control. The first evidence for a role of PPARalpha in inflammation control came from the demonstration that PPARalpha deficient mice display a prolonged response to inflammatory stimuli. It was suggested that PPARalpha deficiency results in a reduced beta-oxidative degradation of these inflammatory fatty acid derivatives. More recently, PPAR activators were shown to inhibit the activation of inflammatory response genes (such as IL-2, IL-6, IL-8, TNFalpha and metalloproteases) by negatively interfering with the NF- kappaB, STAT and AP-1 signalling pathways. PPAR activators exert these anti-inflammatory activities in different immunological and vascular wall cell types such as monocyte/macrophages, endothelial, epithelial and smooth muscle cells in which PPARs are expressed. These recent findings indicate a modulatory role for PPARs in the control of the inflammatory response with potential therapeutic applications in inflammation-related diseases, such as atherosclerosis and inflammatory bowel disease.
...
PMID:Peroxisome proliferator-activated receptors (PPARs): nuclear receptors at the crossroads between lipid metabolism and inflammation. 1108

Ligands for peroxisome proliferator-activated receptor gamma (PPARgamma), such as 15-deoxy-Delta(12,14)PGJ2 (15d-PGJ2) have been proposed as a new class of antiinflammatory compounds with possible clinical applications. As there is some controversy over the inhibitory effects of 15d-PGJ2 on chemokine gene expression, we investigated whether 15d-PGJ2 itself affected chemokine gene expression in human monocytes/macrophages and two monocytic cell lines. Here we demonstrate that the 15d-PGJ2 can induce IL-8 gene expression. In contrast, monocyte chemoattractant protein-1 gene expression was suppressed by 15d-PGJ2, while the expression of RANTES was unaltered. Furthermore, concomitant treatment of monocytes/macrophages with 15d-PGJ2 (2.5 x 10(-6) M) potentiated LPS-induced gene expression of IL-8 mRNA, but suppressed PMA-induction of IL-8 mRNA. In addition, treatment of U937 and THP-1 cells with 15d-PGJ2 also resulted in induction of IL-8 gene expression. Further studies demonstrated that 15d-PGJ2 regulated IL-8 gene expression via a ligand-specific and PPARgamma-dependent pathway. Our observations revealed a previous unappreciated function and mechanism of 15d-PGJ2-mediated regulation of cytokine gene expression in monocytes/macrophages.
...
PMID:Differential regulation of chemokine gene expression by 15-deoxy-delta 12,14 prostaglandin J2. 1139 Apr 55

Helicobacter pylori colonization leads to epithelial cell hyperproliferation within inflamed mucosa, but levels of apoptosis vary, suggesting that imbalances between rates of cell production and loss may contribute to differences in gastric cancer risk among infected populations. Peroxisome proliferator-activated receptor gamma (PPARgamma) regulates inflammatory and growth responses of intestinal epithelial cells. We determined whether activation of PPARgamma modified H. pylori-induced apoptosis in gastric epithelial cells. PPARgamma was expressed and functionally active in gastric epithelial cell lines sensitive to H. pylori-induced apoptosis. PPARgamma ligands 15d-PGJ(2) and BRL-49653 significantly attenuated H. pylomicronri-induced apoptosis, effects that could be reversed by co-treatment with a specific PPARgamma antagonist. Cyclopentanone prostaglandins that do not bind and activate PPARgamma had no effects on H. pylori-induced apoptosis. The ability of H. pylori to activate nuclear factor (NF)-kappaB and increase levels of the NF-kappaB target IL-8 was blocked by co-treatment with PPARgamma agonists, and direct inhibition of NF-kappaB also abolished H. pylori-stimulated apoptosis. These results suggest that activation of the PPARgamma pathway attenuates the ability of H. pylori to induce NF-kappaB-mediated apoptosis in gastric epithelial cells. Because PPARgamma regulates a multitude of host responses, activation of this receptor may contribute to varying levels of cellular turnover as well as the diverse pathologic outcomes associated with chronic H. pylori colonization.
...
PMID:Activation of peroxisome proliferator-activated receptor gamma suppresses nuclear factor kappa B-mediated apoptosis induced by Helicobacter pylori in gastric epithelial cells. 1139 15

The peroxisome proliferator-activated receptors (PPARs) are nuclear hormone transcription factors that regulate genes associated with lipid and glucose metabolism. Recent evidence suggests that PPAR-gamma may also act as a negative immunomodulator. To investigate the potential role of PPAR-gamma in regulating airway inflammation, we characterized the expression and function of PPAR-gamma in airway epithelial cells. Airway epithelial cells constitutively express PPAR-gamma-specific messenger RNA and protein. Further, airway epithelial PPAR-gamma is inducible by interleukin (IL)-4 in NIH-A549 cells. Two PPAR-gamma agonists, the prostaglandin D2 metabolite 15-deoxy-(Delta)(12,14) prostaglandin J2 (15d-PGJ2) and a thiazolidinedione, ciglitazone, were used to study the effects of PPAR-gamma activation on airway epithelial cytokine expression. Activation of PPAR-gamma stimulated a PPAR-responsive reporter gene in a ligand-specific manner. In NIH-A549 cells, both ligands also blocked the cytokine-induced expression of the inducible form of nitric oxide synthase in a dose-dependent manner. In contrast, ciglitazone alone had a slight effect on cytokine-induced IL-8 secretion, but markedly inhibited IL-8 secretion from cells pretreated with IL-4. The demonstration of PPAR-gamma expression and function in airway epithelial cells expands the immunoregulatory role of PPARs and suggests a critical role for PPAR-gamma in antagonizing proinflammatory pathways in the airways.
...
PMID:Peroxisome proliferator-activated receptor-gamma regulates airway epithelial cell activation. 1141 33

Peroxisome proliferator-activated receptor gamma (PPARgamma) is a ligand dependent transcriptional factor known to be a regulator of adipogenesis. Recent studies have also shown that stimulation of PPARgamma inhibits the transcriptional activities of other nuclear factors and down-regulates proinflammatory cytokine synthesis in T cells and monocytes. We examined, in the present study, the functional significance of PPARgamma expressed in fibroblast-like synovial cells (FLS) isolated from patients with rheumatoid arthritis (RA). Incubation of FLS with a synthetic PPARgamma ligand, troglitazone, inhibited endogenous production of TNF-alpha, IL-6 and IL-8, as well as matrix metalloprotease-3 (MMP-3), without inducing apoptosis of the cells. The gelatinase activity of FLS culture media was also inhibited by troglitazone. Electrophoretic mobility shift assay (EMSA) showed a significant reduction in the DNA binding activity of NF-kappaB in troglitazone-treated FLS in response to TNF-alpha or IL-1beta. Moreover, long-term cultivation of FLS with troglitazone resulted in morphological changes with marked lipid accumulation in these cells. Our results show a negative regulatory function for PPARgamma on cytokine and MMP production together with inhibition of cytokine-mediated inflammatory responses in rheumatoid synovial cells. Our results also suggest that FLS could differentiate into adipocyte-like cells in the presence of proper stimulatory signals including PPARgamma.
...
PMID:Functional changes in rheumatoid fibroblast-like synovial cells through activation of peroxisome proliferator-activated receptor gamma-mediated signalling pathway. 1216 97

Peroxisome proliferator-activated receptor (PPAR)-gamma is a ligand-dependent nuclear receptor that is essential for murine placental development and trophoblast differentiation. In nonreproductive tissues, PPAR-gamma regulates the formation of proinflammatory cytokines. Evidence suggests that many of the observed anti-inflammatory effects of PPAR-gamma are in part caused by antagonizing the activities of the transcription factors, including nuclear factor-kappa B. The aim of this study was to elucidate whether natural [15-deoxy-Delta(12,14)-PGJ(2) (15d-PGJ(2))] and synthetic (troglitazone) PPAR-gamma ligands regulate the secretion of IL-6, IL-8, and TNF-alpha from human intrauterine tissues. Human placenta, amnion, and choriodecidual tissues were incubated in the presence of 10 micro g/ml lipopolysaccharide in the absence (control) or presence of 30 micro M 15d-PGJ(2) (n = 6 independent placenta) or troglitazone (n = 6 independent placentas). After a 6-h incubation, the incubation medium was collected and the release of IL-6, IL-8, and TNF-alpha was quantified by ELISA. Treatment of placental, amnion, and choriodecidual tissues with both 15d-PGJ(2) and troglitazone significantly reduced the release of lipopolysaccharide-stimulated IL-6, IL-8, and TNF-alpha (t test, P < 0.05). Gel shift analyses demonstrated that 15d-PGJ(2), but not troglitazone, suppressed nuclear factor-kappa B DNA-binding activity. The data presented in this study demonstrate that the formation of proinflammatory mediators can be modulated by currently available therapeutic agents and may therefore be of therapeutic potential in human labor.
...
PMID:Regulation of proinflammatory cytokines in human gestational tissues by peroxisome proliferator-activated receptor-gamma: effect of 15-deoxy-Delta(12,14)-PGJ(2) and troglitazone. 1236 56

1. Peroxisome proliferator-activated receptors (PPARs) are ligand-activated transcription factors that have been proposed to regulate inflammation by antagonising the nuclear factor-kappaB (NF-kappaB) signalling pathway. We investigated the role of PPARs using synthetic agonists in murine models of airway inflammation, and addressed the possible effect on NF-kappaB signalling in vitro using a human epithelial cell line, A549. 2. Sensitised BALB/c mice exposed to an aerosol solution of ovalbumin had an increased number of airway eosinophils, neutrophils and lymphocytes. When given intranasally an hour before the aerosol challenge, a PPAR-alpha (GW 9578) and PPAR-gamma (GI 262570) selective agonist as well as a dual PPAR-alpha/gamma (GW 2331) agonist selectively inhibited allergen-induced bronchoalveolar lavage eosinophil and lymphocyte but not neutrophil influx. In contrast, a PPAR-delta agonist (GW 501516) was inactive. 3. When given intranasally an hour before challenge, PPAR-alpha and PPAR-gamma selective agonists as well as a dual PPAR-alpha/gamma agonist did not inhibit lipopolysaccharide-induced bronchoalveolar lavage neutrophil influx or tumour necrosis factor-alpha (TNF-alpha) and KC production. 4. In A549 cells, selective agonists for PPAR-alpha, -gamma and -delta did not inhibit intracellular adhesion molecule-1 expression following stimulation with proinflammatory cytokines. In addition, IL-8 release and the activation of an NF-kappaB-responsive reporter gene construct were inhibited only at micromolar concentrations, suggesting that these effects were not PPAR-mediated. 5. Our in vivo data show that agonists of PPAR-alpha and -gamma, but not -delta, inhibit allergen-induced bronchoalveolar lavage eosinophil and lymphocyte influx. In vitro data suggest that this effect might not be mediated by antagonism of the NF-kappaB pathway.
...
PMID:PPAR-alpha and -gamma but not -delta agonists inhibit airway inflammation in a murine model of asthma: in vitro evidence for an NF-kappaB-independent effect. 1274 35

Several studies have shown a relationship between interleukin (IL) 6 levels and insulin resistance. We here show that human subcutaneous adipose cells, like 3T3-L1 cells, are target cells for IL-6. To examine putative mechanisms and cross-talk with insulin, 3T3-L1 adipocytes were cultured for different times with IL-6 and tumor necrosis factor alpha (TNF-alpha). IL-6, in contrast to TNF-alpha, did not increase pS-307 of insulin-receptor substrate (IRS)-1 or JNK activation. However, IL-6, like TNF-alpha exerted long term inhibitory effects on the gene transcription of IRS-1, GLUT-4, and peroxisome proliferator-activated receptor gamma. This effect of IL-6 was accompanied by a marked reduction in IRS-1, but not IRS-2, protein expression, and insulin-stimulated tyrosine phosphorylation, whereas no inhibitory effect was seen on the insulin receptor tyrosine phosphorylation. Consistent with the reduced GLUT-4 mRNA, insulin-stimulated glucose transport was also significantly reduced by IL-6. An important interaction with TNF-alpha was found because TNF-alpha markedly increased IL-6 mRNA and protein secretion. These results show that IL-6, through effects on gene transcription, is capable of impairing insulin signaling and action but, in contrast to TNF-alpha, IL-6 does not increase pS-307 (or pS-612) of IRS-1. The link between IL-6 and insulin resistance in man was further corroborated by the finding that the expression of IL-6, like that of TNF-alpha and IL-8, was markedly increased ( approximately 15-fold) in human fat cells from insulin-resistant individuals. We conclude that IL-6 can play an important role in insulin resistance in man and, furthermore, that it may act in concert with other cytokines that also are up-regulated in adipose cells in insulin resistance.
...
PMID:Interleukin-6 (IL-6) induces insulin resistance in 3T3-L1 adipocytes and is, like IL-8 and tumor necrosis factor-alpha, overexpressed in human fat cells from insulin-resistant subjects. 1295 69

Cyclooxygenase-2 (COX-2) expression and certain growth hormones, such as gastrin, have been related to gastric carcinogenesis, but little is known about the factors that enhance this COX-2 expression and whether specific blockade of this enzyme has any influence on tumor growth and progression. Our objective was to determine the influence of a specific COX-2 inhibitor, rofecoxib (Vioxx), on serum and tumor levels of gastrin and its precursor, progastrin, as well as on tumor gene expression of COX-2, peroxisome proliferator-activated receptor gamma (PPARgamma), and apoptosis-related proteins (Bax and Bcl-2, caspase-3, and survivin). Twenty-four gastric cancer (GC) patients entered this study and were examined twice, once before and then following a 14-day treatment with Vioxx at a dose of 25 mg twice daily. For comparison, 48 age- and sex-matched healthy controls and 24 similarly matched Helicobacter pylori (Hp)-positive subjects were enrolled and treated with Vioxx as GC patients. Serum levels of anti-Hp and anti-CagA antibodies as well as IL-8 and TNF-alpha were measured by enzyme-linked immunosorbent assay (ELISA), while serum and tumor contents of progastrin and amidated gastrin were determined by specific RIA. Tumor gene and protein expressions of COX-2, PPARgamma, Bax and Bcl-2, caspase-3, and survivin were determined by RT-PCR and western blot. The overall Hp and CagA seropositivity in 24 GC patients was significantly higher (82% and 47%) than in 48 controls (61% and 22%) but not in 24 Hp-infected subjects (100% and 38%). Serum IL-8 and TNF-alpha values were significantly higher in GC patients than in controls without GC or Hp-infected controls. Median serum progastrin and gastrin levels were found to be significantly higher in GC than in controls without GC and in Hp-positive subjects. Treatment of GC patients with Vioxx resulted in a significant decrease in plasma and tumor contents of both progastrin and gastrin, and this was accompanied by the increment in tumor expression of COX-2, PPARy, Bax, and caspase-3 with a concomitant reduction in Bcl-2 and survivin expression. We conclude that: (1) GC patients show significantly higher Hp and CagA seropositivity than age- and sex-matched controls, but not Hp-positive subjects, indicating that infection with cytotoxic Hp is linked to GC. (2) Serum progastrin and gastrin levels are significantly higher in GC patients than in matched controls, confirming that both gastrins may be implicated in gastric carcinogenesis. (3) GC patients exhibit significantly higher levels of IL-8 and TNF-alpha than non-GC controls and Hp-positive subjects, probably reflecting more widespread gastritis in GC. (4) COX-2, PPARgamma, Bcl-2, and survivin were overexpressed in gastric tumor, but the inhibition of COX-2 activity by Vioxx resulted in a significant reduction in serum and tumor levels of progastrin and gastrin and serum IL-8 and TNF-alpha levels, suggesting that gastrin and proinflammatory cytokines could mediate the up-regulation of COX-2 in gastric cancerogenesis. (5) Vioxx also enhanced expression of COX-2, PPARy, Bax, and caspase-3, while inhibiting the expression of Bcl-2 and survivin, suggesting that COX-2 blockade might be useful in chemoprevention against gastric cancer possibly due to enhancement of the PPARy- and proapoptotic proteins-dependent apoptosis and the reduction in progastrin/gastrin-induced promotion of tumor growth.
...
PMID:Influence of COX-2 inhibition by rofecoxib on serum and tumor progastrin and gastrin levels and expression of PPARgamma and apoptosis-related proteins in gastric cancer patients. 1462 49

1 2 3 4 5 Next >>