We investigated whether NS-398, a selective inhibitor of COX-2, induces HO-1 in IL-1β-stimulated vascular smooth muscle cells (VSMC). NS-398 reduced the production of PGE2 without modulation of expression of COX-2 in IL-1β-stimulated VSMC. NS-398 increased HO-1 mRNA and protein in a dose-dependent manner, but inhibited proliferation of IL-1β-stimulated VSMC. Furthermore, SnPPIX, a HO-1 inhibitor, reversed the effects of NS-398 on PGE2 production, suggesting that COX-2 activity can be affected by HO-1. Hemin, a HO-1 inducer, also reduced the production of PGE2 and proliferation of IL-1β-stimulated VSMC. CORM-2, a CO-releasing molecule, but not bilirubin inhibited proliferation of IL-1β-stimulated VSMC. NS-398 inhibited proliferation of IL-1β-stimulated VSMC in a HbO2-sensitive manner. In conclusion, NS-398 inhibits proliferation of IL-1β-stimulated VSMC by HO-1-derived CO. Thus, NS-398 may facilitate the healing process of vessels in vascular inflammatory disorders such as atherosclerosis. 相似文献
Tranilast (N-[3′,4′-dimethoxycinnamonyl] anthranilic acid), an orally active anti-allergic drug, is reported to exert the anti-inflammatory effects, but the underlying mechanisms that could explain the anti-inflammatory actions of tranilast remain largely unknown. Here, we found that tranilast induces heme oxygenase-1 (HO-1) expression through the extracellular signal-regulated kinase-1/2 (ERK1/2) pathway in RAW264.7 macrophages. Tranilast suppressed cyclooxygenase-2 (COX-2) and inducible nitric oxide (NO) synthase (iNOS) expression, and thereby reduced COX-2-derived prostaglandin E2 (PGE2) and iNOS-derived NO production in lipopolysaccharide (LPS)-stimulated macrophages. Similarly, tranilast diminished tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) production. Interestingly, the effects of tranilast on LPS-induced PGE2, NO, TNF-α, and IL-1β production were partially reversed by the HO-1 inhibitor tin protoporphyrin, suggesting that tranilast-induced HO-1 expression is at least partly responsible for the resulting anti-inflammatory effects of the drug. Thus, HO-1 expression via ERK1/2 activation may be at least one of the possible mechanisms explaining the anti-inflammatory actions of tranilast. 相似文献
Proinflammatory cytokines may promote preterm labor in the setting of intrauterine infection. Tumor necrosis factor (TNF) and interleukin-1 (IL-1) synergistically stimulate the production of prostaglandin E2 (PGE2) by amnion cells. Transforming growth factor-β (TGF-β) inhibits the cytokine-stimulated PGE2 production. In the present study, we investigated the binding of IL-1β on human amnion cells in culture. Untreated amnion cells possessed 540±60 IL-1 receptors per cell, with a dissociation constant of 1.4±0.4 nM. Cells treated with TGF-β1 (10 ng/ml) had 570±110 receptors per cell. TNF-α (50 ng/ml) increased the number of IL-1 receptors to 2930±590. TGF-β1 inhibited the receptor upregulation by TNF-α. Cells treated with TGF-β1 and TNF-α expressed 1140±590 receptors per cell. The binding affinity was not changed by the cytokines. IL-1 receptor antagonist (IL-1ra) inhibited the stimulation of amnion cell PGE2 production by IL-1β, but not by TNF-α. Amnion cells secreted large amounts of IL-1ra (1.1±0.3 ng/105 cells). Treatment of the cells with TGF-β1 or TNF-α did not affect the release of IL-1ra. We conclude that IL-1 receptor expression is an important step in the regulation of the effects of cytokines on amnion cell PGE2 production. 相似文献
Understanding the mechanisms of sphingosine 1-phosphate (S1P)-induced cyclooxygenase (COX)-2 expression and prostaglandin E2 (PGE2) formation in renal mesangial cells may provide potential therapeutic targets to treat inflammatory glomerular diseases. Thus, we evaluated the S1P-dependent signaling mechanisms which are responsible for enhanced COX-2 expression and PGE2 formation in rat mesangial cells under basal conditions. Furthermore, we investigated whether these mechanisms are operative in the presence of angiotensin II (Ang II) and of the pro-inflammatory cytokine interleukin-1β (IL-1β). 相似文献
Alzheimer's disease (AD) is the most common form of dementia and displays the characteristics of chronic neurodegenerative disorders; amyloid plaques (AP) that contain amyloid β‐protein (Aβ) accumulate in AD, which is also characterized by tau phosphorylation. Epidemiological evidence has demonstrated that long‐term treatment with nonsteroidal anti‐inflammatory drugs (NSAIDs) markedly reduces the risk of AD by inhibiting the expression of cyclooxygenase 2 (COX‐2). Although the levels of COX‐2 and its metabolic product prostaglandin (PG)E2 are elevated in the brain of AD patients, the mechanisms for the development of AD remain unknown. Using human‐ or mouse‐derived glioblastoma and neuroblastoma cell lines as model systems, we delineated the signaling pathways by which COX‐2 mediates the reciprocal regulation of interleukin‐1β (IL‐1β) and Aβ between glial and neuron cells. In glioblastoma cells, COX‐2 regulates the synthesis of IL‐1β in a PGE2‐dependent manner. Moreover, COX‐2‐derived PGE2 signals the activation of the PI3‐K/AKT and PKA/CREB pathways via cyclic AMP; these pathways transactivate the NF‐κB p65 subunit via phosphorylation at Ser 536 and Ser 276, leading to IL‐1β synthesis. The secretion of IL‐1β from glioblastoma cells in turn stimulates the expression of COX‐2 in human or mouse neuroblastoma cells. Similar regulatory mechanisms were found for the COX‐2 regulation of BACE‐1 expression in neuroblastoma cells. More importantly, Aβ deposition mediated the inflammatory response of glial cells via inducing the expression of COX‐2 in glioblastoma cells. These findings not only provide new insights into the mechanisms of COX‐2‐induced AD but also initially define the therapeutic targets of AD. 相似文献
The degradative effects of interleukin-1 (IL-1) on the extracellular matrix of connective tissue are mediated primarily by metalloproteinases and prostaglandins. Clinical observations suggest that these effects can be prevented, to some extent, by the use of non-steroidal anti-inflammatory drugs. We have examined the role of prostaglandin E2 (PGE2) in IL-1-induced gene expression by human skin fibroblasts in culture. Incubation of confluent fibroblast cultures with varying concentrations (0.01–1.0 μg/ml) of PGE2 led to a dose-dependent elevation of collagenase mRNA steady-state levels, the promoter activity, and the secretion of the protein, whereas relatively little effect was observed on stromelysin and TIMP gene expression. Exogenous PGE2 had no additive or synergistic effect with IL-1 on collagenase gene expression. Furthermore, commonly used non-steroidal anti-inflammatory drugs (indomethacin, acetyl salicylic acid and ibuprofen), at doses which block prostaglandin synthesis in cultured fibroblasts, failed to counteract IL-1-induced collagenase and stromelysin gene expression, nor did they affect TIMP expression. Although the effects of PGE2 did not potentiate those of IL-1 on collagenase gene expression in vitro, one could speculate that massive production of PGE2 by connective tissue cells in vivo in response to inflammatory mediators such as IL-1 or tumor necrosis factor-α, could lead to sustained expression of collagenase in connective tissue cells after clearance of the growth factors. 相似文献
During endometrial inflammation, bovine endometrium responds by increasing the production of pro-inflammatory mediators, such as interleukin 1 beta (IL-1β), tumor necrosis factor alpha (TNFα), and eicosanoids. The purpose of this study was to establish and characterize an in vitro model of endometrial inflammation using bovine endometrial epithelial (bEEL) and stromal (bCSC) cell lines. We evaluated the effects of the infectious agent (bacterial lipopolysaccharide; LPS) and pro-inflammatory mediators (IL-1β and TNFα) on eicosanoid biosynthesis pathway gene expression and production by bEEL and bCSC cells. Based on concentration-response experiments, the optimal concentrations for responses were 1?μg/mL LPS, 10?ng/mL IL-1β and 50?ng/mL TNFα. Real-time PCR results show that there was an upregulation of relative mRNA expression of PTGS2 when bEEL and bCSC were treated with LPS, IL-1β and TNFα. An increase in PTGES3 expression was observed when bEEL cells were treated with LPS and IL-1β and PTGES2 when treated with IL-1β. In bCSC cells, FAAH relative mRNA was decreased upon treatments. Rate of production of PGE2, PGF2α, PGE2-EA and PGF2α-EA were also determined using liquid chromatography tandem mass spectrometry. Our results show that eicosanoid production was increased in both cell lines in response to LPS, IL-1β, and TNFα. We suggest that the characteristics of bEEL and bCSC cell lines mimic the physiological responses found in mammals with endometrial infection, making them excellent in vitro models for intrauterine environment studies. 相似文献
Abstract: The involvement of protein kinase C and its interaction with interleukin 1β in the control of interleukin 6 release by cortical astrocytes was studied. The blockade of protein kinase C catalytic domain, by staurosporine, as well as the desensitization of protein kinase C by short-term phorbol 12-myristate 13-acetate pretreatment, increased the basal release of interleukin 6 by rat cortical astrocytes, whereas calphostin C, an antagonist of phorbol ester binding on protein kinase C regulatory domain, did not affect the basal release of the cytokine. The activation of protein kinase C by phorbol 12-myristate 13-acetate enhanced concentration- and time-dependently interleukin 6 release. This stimulatory action of phorbol 12-myristate 13-acetate was significantly reduced by staurosporine, by calphostin C, and by the desensitization of protein kinase C. Interleukin 1β increased interleukin 6 release in a concentration-related manner. Protein kinase C inhibition, by staurosporine or desensitization, potentiated severalfold, whereas calphostin C reduced interleukin 1β stimulation of interleukin 6 release. The treatment of cortical astrocytes with both interleukin 1β (3 ng/ml) and phorbol 12-myristate 13-acetate (10 nM) caused a synergistic stimulation of interleukin 6 release and its gene expression, an effect that was not relieved by either 20 nM staurosporine or by calphostin C but was slightly affected by protein kinase C desensitization. In conclusion, our data show that in rat cortical astrocytes the basal release of interleukin 6 is under a tonic inhibition exerted by a protein kinase C isoform or isoforms sensitive to blockade by staurosporine and desensitization but insensitive to calphostin C. Interleukin 1β stimulated interleukin 6 secretion via a mechanism that is also negatively modulated by a protein kinase C isoform or isoforms sensitive to staurosporine and desensitization. Finally, we showed that interleukin 1β and phorbol 12-myristate 13-acetate synergistically stimulated interleukin 6 release and its gene expression, operating in a manner insensitive to protein kinase C blockers and slightly reduced by protein kinase C desensitization. 相似文献
Amyloid‐β peptides generated by proteolysis of the β‐amyloid precursor protein (APP) play an important role in the pathogenesis of Alzheimer's disease. The present study aimed to determine whether cytosolic phospholipase A2α (cPLA2α) plays a role in elevated APP protein expression induced by aggregated amyloid‐β1‐42 (Aβ) in cortical neurons and to elucidate its specific role in signal events leading to APP induction. Elevated cPLA2α and its activity determined by phosphorylation on serine 505 as well as elevated APP protein expression, were detected in primary rat cortical neuronal cultures exposed to Aβ for 24 h and in cortical neuron of human amyloid‐β1‐42 brain infused mice. Prevention of cPLA2α up‐regulation and its activity by oligonucleotide antisense against cPLA2α (AS) prevented the elevation of APP protein in cortical neuronal cultures and in mouse neuronal cortex. To determine the role of cPLA2α in the signals leading to APP induction, increased cPLA2α expression and activity induced by Aβ was prevented by means of AS in neuronal cortical cultures. Under these conditions, the elevated cyclooxygenase‐2 and the production of prostaglandin E2 (PGE2) were prevented. Addition of PGE2 or cyclic AMP analogue (dbcAMP) to neuronal cultures significantly increased the expression of APP protein, while the presence protein kinase A inhibitor (H‐89) attenuated the elevation of APP induced by Aβ. Inhibition of elevated cPLA2α by AS prevented the activation of cAMP response element binding protein (CREB) as detected by its phosphorylated form, its translocation to the nucleus and its DNA binding induced by Aβ which coincided with cPLA2α dependent activation of CREB in the cortex of Aβ brain infused mice. Our results show that accumulation of Aβ induced elevation of APP protein expression mediated by cPLA2α, PGE2 release, and CREB activation via protein kinase A pathway.
Fifteen ewes were assigned as they came into estrus to the following randomized treatment groups: 1) Vehicle (1 ml corn oil + vehicle Na2CO3 buffer), 2) Estradiol-17β + vehicle and 3) Estradiol-17β + PGE2 (500 μg) in Na2CO3 buffer (5 ewes/treatment group). Prostaglandin E2 was given through an intrauterine cannula every four hours from days 8 through 15 postestrus. PGE2 prevented a luteolytic dose of estradiol-17β given on days 9 and 10 from causing a precious luteolysis. PGE2 maintained concentrations of progesterone in peripheral blood (days 8 through 15) and weights and concentrations of progesterone in corpora lutea on day 15 postestrus of ewes receiving estradiol-17β. It is concluded that chronic intrauterine infusions of PGE2 can prevent an estradiol-17β-induced premature luteolysis. 相似文献