scholarly journals Pyrogen–prostaglandin coupling in the pathogenesis of fever: evidence against a role for nitric oxide

1995 ◽  
Vol 73 (10) ◽  
pp. 1466-1474 ◽  
Author(s):  
Jane Redford ◽  
Isis Bishai ◽  
Flavio Coceani

There is much debate on the mechanism by which blood-borne pyrogens trigger prostaglandin E2 (PGE2) synthesis in brain and fever. This investigation was undertaken to determine whether nitric oxide qualifies as a signal transducer for pyrogens at the interface between blood and brain. Experiments were carried out in vitro and in vivo using, respectively, preparations of cerebral tissue and microvessels from the rat, and the conscious, chronically instrumented cat. In vitro preparations produced PGE2 and its production increased during a 30-min treatment with interleukin 1 (brain tissue) or endotoxin (microvessels). In addition, both pyrogens increased cyclic GMP levels in cerebral microvessels. In both brain tissue and microvessels, NG-nitro-L-arginine had no effect on basal PGE2 release, while it curtailed the pyrogen-stimulated release. The same treatment reduced the cyclic GMP accumulation brought about by pyrogens in the microvessels. Conversely, in the conscious cat, inhibitors of nitric oxide synthesis (NG-monomethyl-L-argimne, NG-nitro-L-arginine) had no effect on fever and the concomitant elevation of PGE2 in cerebrospinal fluid, regardless of the pyrogen used (endotoxin, interleukin 1) and the route of administration (intravenous, intracerebroventricular). We conclude that nitric oxide may serve as a pyrogen mediator in brain. This mediator function, however, is seemingly not important in the development of fever.Key words: pyrogen, fever mechanism, nitric oxide, prostaglandin E2, blood–brain barrier.

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Zunpeng Shu ◽  
Na Xing ◽  
Qiuhong Wang ◽  
Xinli Li ◽  
Bingqing Xu ◽  
...  

This study was designed to determine whether the 50% EtOH fraction from AB-8 macroporous resin fractionation of a 70% EtOH extract ofP. Alkekengi(50-EFP) has antibacterial and/or anti-inflammatory activity bothin vivoandin vitroand to investigate the mechanism of 50-EFP anti-inflammatory activity. Additionally, this study sought to define the chemical composition of 50-EFP. Results indicated that 50-EFP showed significant antibacterial activityin vitroand efficacyin vivo. Moreover, 50-EFP significantly reduced nitric oxide (NO), prostaglandin E2(PGE2), tumor necrosis factor alpha (TNF-α), interleukin 1 (IL-1), and interleukin 6 (IL-6) production in lipopolysaccharide- (LPS-) stimulated THP-1 cells. Nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) (examined at the protein level) in THP-1 cells were suppressed by 50-EFP, which inhibited nuclear translocation of p65. Consistent with this anti-inflammatory activityin vitro, 50-EFP reduced inflammation in both animal models. Finally, seventeen compounds (8 physalins and 9 flavones) were isolated as major components of 50-EFP. Our data demonstrate that 50-EFP has antibacterial and anti-inflammatory activities bothin vitroandin vivo. The anti-inflammatory effect appears to occur, at least in part, through the inhibition of nuclear translocation of p65. Moreover, physalins and flavones are probably the active components in 50-EFP that exert antibacterial and anti-inflammatory activities.


2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Hsueh-Ling Cheng ◽  
Nurkholis ◽  
Shi-Yie Cheng ◽  
Shen-Da Huang ◽  
Yan-Ting Lu ◽  
...  

Fatsia polycarpa, a plant endemic to Taiwan, is an herbal medicine known for treating several inflammation-related diseases, but its biological function needs scientific support. Thus, the anti-inflammatory effects and mechanisms of the methanolic crude extract (MCE) ofF. polycarpaand its feature constituents, that is, brassicasterol (a phytosterol), triterpenoids 3α-hydroxyolean-11,13(18)-dien-28-oic acid (HODA), 3α-hydroxyolean-11-en-28,13β-olide (HOEO), fatsicarpain D, and fatsicarpain F, were investigated. MCE and HOEO, but not brassicasterol, dose-dependently inhibited lipopolysaccharide- (LPS-)induced expression of inducible nitric oxide synthase and cyclooxygenase-2 in RAW 264.7 macrophage line, whereas HODA, fatsicarpain D and fatsicarpain F were toxic to RAW cells. Additionally, MCE and HOEO suppressed LPS-induced production of nitric oxide, prostaglandin E2, and interleukin-1βand interfered with LPS-promoted activation of the inhibitor kappa B kinase (IKK)/nuclear factor-κB (NF-κB) pathway, and that of the mitogen-activated protein kinases (MAPKs) extracellular signal regulated kinase (ERK), c-Jun N-terminal kinase (JNK), and p38. In animal tests, MCE and HOEO effectively ameliorated 12-O-tetradecanoylphorobol-13 acetate- (TPA-)induced ear edema of mice. Thus, MCE ofF. polycarpaexhibited an obvious anti-inflammatory activityin vivoandin vitrothat likely involved the inhibition of the IKK/NF-κB pathway and the MAPKs, which may be attributed by triterpenoids such as HOEO.


2020 ◽  
Vol 23 (1) ◽  
Author(s):  
Lei Wang ◽  
You-Jin Jeon ◽  
Jae-Il Kim

Abstract Background Inflammation plays a crucial role in the pathogenesis of many diseases such as arthritis and atherosclerosis. In the present study, we evaluated anti-inflammatory activity of sterol-rich fraction prepared from Spirogyra sp., a freshwater green alga, in an effort to find bioactive extracts derived from natural sources. Methods The sterol content of ethanol extract of Spirogyra sp. (SPE) was enriched by fractionation with hexane (SPEH), resulting 6.7 times higher than SPE. Using this fraction, the in vitro and in vivo anti-inflammatory activities were evaluated in lipopolysaccharides (LPS)-stimulated RAW 264.7 cells and zebrafish. Results SPEH effectively and dose-dependently decreased the production of nitric oxide (NO) and prostaglandin E2 (PGE2). SPEH suppressed the production of pro-inflammatory cytokines including interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and IL-1β through downregulating nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) expression in LPS-stimulated RAW 264.7 cells without cytotoxicity. The in vivo test results indicated that SPEH significantly and dose-dependently reduced reactive oxygen species (ROS) generation, cell death, and NO production in LPS-stimulated zebrafish. Conclusions These results demonstrate that SPEH possesses strong in vitro and in vivo anti-inflammatory activities and has the potential to be used as healthcare or pharmaceutical material for the treatment of inflammatory diseases.


2013 ◽  
Vol 2013 ◽  
pp. 1-19 ◽  
Author(s):  
Ji Young Cha ◽  
Ji Yun Jung ◽  
Jae Yup Jung ◽  
Jong Rok Lee ◽  
Il Je Cho ◽  
...  

Pyungwi-san (PWS) is a traditional basic herbal formula. We investigated the effects of PWS on induction of cyclooxygenase-2 (COX-2), inducible nitric oxide synthase (iNOS), pro-inflammatory cytokines (interleukin-6 (IL-6) and tumor necrosis factor-α(TNF-α)) and nuclear factor-kappa B (NF-κB) as well as mitogen-activated protein kinases (MAPKs) in lipopolysaccharide-(LPS-) induced Raw 264.7 cells and on paw edema in rats. Treatment with PWS (0.5, 0.75, and 1 mg/mL) resulted in inhibited levels of expression of LPS-induced COX-2, iNOS, NF-κB, and MAPKs as well as production of prostaglandin E2(PGE2), nitric oxide (NO), IL-6, and TNF-αinduced by LPS. Our results demonstrate that PWS possesses anti-inflammatory activities via decreasing production of pro-inflammatory mediators through suppression of the signaling pathways of NF-κB and MAPKs in LPS-induced macrophage cells. More importantly, results of the carrageenan-(CA-) induced paw edema demonstrate an anti-edema effect of PWS. In addition, it is considered that PWS also inhibits the acute edematous inflammations through suppression of mast cell degranulations and inflammatory mediators, including COX-2, iNOS and TNF-α. Thus, our findings may provide scientific evidence to explain the anti-inflammatory properties of PWSin vitroandin vivo.


2021 ◽  
Author(s):  
Gaosheng Zhu ◽  
Keze Miao ◽  
Mingwei Dong ◽  
Jie Cai ◽  
Zhihao Shen ◽  
...  

Abstract Osteoarthritis (OA), a prevalent disabling disease, is characterized by irreversible cartilage degradation and persistent inflammation. The etiology as well as pathogenesis of OA are not completely unclear and need further investigation. Gigantol, is a bibenzyl derivative extracted from Dendrobium plants and has been found exhibit multiple effects such as anti-inflammatory effects. Nevertheless, the biological function of gigantol on osteoarthritis (OA) is still uncertain. This study aimed at examining the anti-inflammatory effects and latent mechanisms of gigantol in IL-1β-mediated OA progression. In vitro, we identified that gigantol treatment suppressed tumor necrosis factor-alpha (TNF-α), nitric oxide (NO), cyclooxygenase-2 (COX-2), prostaglandin E2 (PGE2), inducible nitric oxide synthase (iNOS) and interleukin-6 (IL-6) in interleukin-1 beta (IL-1β) mediated mouse OA chondrocytes. Gigantol was also shown to dose dependently downregulate the metalloproteinase 13 (MMP13) as well as thrombospondin motifs 5 (ADAMTS5) levels. Moreover, IL-1β-mediated AKT and PI3K phosphorylation as well as NF-κB activation were inhibited by gigantol. Meanwhile, in vivo, we detected that gigantol treatment inhibited degradation of the cartilage degradation and lowered the Osteoarthritis Research Society International scores (OARSI) in OA mouse. Therefore, gigantol is a promising therapeutic option for OA.


2018 ◽  
Author(s):  
Vu Thao-Vi Dao ◽  
Mahmoud H. Elbatreek ◽  
Martin Deile ◽  
Pavel I. Nedvetsky ◽  
Andreas Güldner ◽  
...  

AbstractNitric oxide (NO)-cyclic GMP (cGMP) signaling is a vasoprotective pathway therapeutically targeted for example in pulmonary hypertension. Its dysregulation in disease is incompletely understood. Here we show in pulmonary artery endothelial cells that feedback inhibition by NO of the NO receptor, the cGMP forming soluble guanylate cyclase (sGC), may contribute to this. Both endogenous NO from endothelial NO synthase or exogenous NO from NO donor compounds decreased sGC protein and activity. This was not mediated by cGMP as the NO-independent sGC stimulator or direct activation of cGMP-dependent protein kinase did not mimic it. Thiol-sensitive mechanisms were also not involved as the thiol-reducing agent, N-acetyl-L-cysteine did not prevent this feedback. Instead, both in-vitro and in-vivo and in health and acute respiratory lung disease, chronically elevated NO led to the inactivation and degradation of sGC whilst leaving the heme-free isoform, apo-sGC, intact or even increasing its levels. Thus, NO regulates sGC in a bimodal manner, acutely stimulating and chronically inhibiting, as part of self-limiting direct feedback that is cGMP-independent. In high NO disease conditions, this is aggravated but can be functionally recovered in a mechanism-based manner by apo-sGC activators that re-establish cGMP formation.


2016 ◽  
Vol 310 (11) ◽  
pp. L1111-L1120 ◽  
Author(s):  
Jennifer M. Dolan ◽  
Jason B. Weinberg ◽  
Edmund O'Brien ◽  
Anya Abashian ◽  
Megan C. Procario ◽  
...  

The production of prostaglandin E2 (PGE2) increases dramatically during pneumococcal pneumonia, and this lipid mediator impairs alveolar macrophage (AM)-mediated innate immune responses. Microsomal prostaglandin E synthase-1 (mPGES-1) is a key enzyme involved in the synthesis of PGE2, and its expression is enhanced during bacterial infections. Genetic deletion of mPGES-1 in mice results in diminished PGE2 production and elevated levels of other prostaglandins after infection. Since PGE2 plays an important immunoregulatory role during bacterial pneumonia we assessed the impact of mPGES-1 deletion in the host defense against pneumococcal pneumonia in vivo and in AMs in vitro. Wild-type (WT) and mPGES-1 knockout (KO) mice were challenged with Streptococcus pneumoniae via the intratracheal route. Compared with WT animals, we observed reduced survival and increased lung and spleen bacterial burdens in mPGES-1 KO mice 24 and 48 h after S. pneumoniae infection. While we found modest differences between WT and mPGES-1 KO mice in pulmonary cytokines, AMs from mPGES-1 KO mice exhibited defective killing of ingested bacteria in vitro that was associated with diminished inducible nitric oxide synthase expression and reduced nitric oxide (NO) synthesis. Treatment of AMs from mPGES-1 KO mice with an NO donor restored bacterial killing in vitro. These results suggest that mPGES-1 plays a critical role in bacterial pneumonia and that genetic ablation of this enzyme results in diminished pulmonary host defense in vivo and in vitro. These results suggest that specific inhibition of PGE2 synthesis by targeting mPGES-1 may weaken host defense against bacterial infections.


Diabetes ◽  
1996 ◽  
Vol 45 (6) ◽  
pp. 771-778 ◽  
Author(s):  
J. I. Reimers ◽  
H. U. Andersen ◽  
D. Mauricio ◽  
F. Pociot ◽  
A. E. Karlsen ◽  
...  

2006 ◽  
Vol 13 (1) ◽  
pp. 106-115 ◽  
Author(s):  
Kenneth C. Bagley ◽  
Sayed F. Abdelwahab ◽  
Robert G. Tuskan ◽  
George K. Lewis

ABSTRACT Cholera toxin (CT) is a potent adjuvant that activates dendritic cells (DC) by increasing intracellular cyclic AMP (cAMP) levels. In vivo and in vitro, very small amounts of CT induce potent adjuvant effects and activate DC. We hypothesized that DC intoxicated by CT may release factors that enhance their own maturation and induce the maturation of toxin-free bystander DC. Through the use of mixed cultures and transwell cultures, we found that human monocyte-derived DC (MDDC) pulsed with CT or other cAMP-elevating agonists induce the maturation of bystander DC. Many DC agonists including CT increase the production of prostaglandin E2 (PGE2) and nitric oxide (NO). For this reason, we determined whether the actions of PGE2 or NO are involved in the maturation of MDDC induced by CT or dibutyryl-cAMP (d-cAMP). We found that blocking the production of PGE2 or blocking prostaglandin receptors inhibited MDDC maturation induced by CT and d-cAMP. Likewise, sequestering NO or blocking the downstream actions of NO resulted in the inhibition of MDDC maturation induced by CT and d-cAMP. These results indicate that endogenously produced factors including PGE2 and NO contribute to the maturation of DC induced by CT and that these factors participate in bystander DC maturation. The results of this study may help explain why bacterial toxins that elevate cAMP are such potent adjuvants.


1994 ◽  
Vol 86 (2) ◽  
pp. 195-202 ◽  
Author(s):  
E. Hardy ◽  
P. C. Rubin ◽  
E. H. Horn

1. Platelet activation in vivo occurs in healthy pregnancy and is more pronounced in pre-eclampsia. 2. This study has investigated: (i) the inhibitory potency of the nitric oxide donors 3-morpholinosydnonimine and sodium nitroprusside, on the platelet release reaction in vitro in non-pregnant, healthy pregnant and pre-eclamptic women; (ii) the concentration of cyclic GMP during incubation of washed platelets with sodium nitroprusside in a separate group of non-pregnant, healthy pregnant and pre-eclamptic women. 3. The half-maximal inhibitory concentration of sodium nitroprusside, in the presence of a phosphodiesterase inhibitor, for inhibition of the platelet release reaction was lower in the pre-eclamptic subjects than in the non-pregnant subjects (P < 0.05). 4. Several of the pre-eclamptic women were studied again postnatally. The half-maximal inhibitory concentrations of sodium nitroprusside and 3-morpholinosydnonimine were higher in the postnatal than in the antenatal sample (P < 0.02). 5. Peak platelet cyclic GMP responses to sodium nitroprusside were significantly higher in the pre-eclamptic women than in the healthy pregnant and non-pregnant women. 6. These results suggest that platelets are more sensitive to the inhibitory effects of nitric oxide donors in pre-eclampsia.


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