scholarly journals Cryptococcal Glucuronoxylomannan Inhibits Adhesion of Neutrophils to Stimulated Endothelium In Vitro by Affecting Both Neutrophils and Endothelial Cells

2002 ◽  
Vol 70 (9) ◽  
pp. 4762-4771 ◽  
Author(s):  
Pauline M. Ellerbroek ◽  
Andy I. M. Hoepelman ◽  
Floor Wolbers ◽  
Jaap Jan Zwaginga ◽  
Frank E. J. Coenjaerts
Keyword(s):  
Capsular Polysaccharide ◽  
Inhibitory Effect ◽  
Intercellular Adhesion Molecule ◽  
Intercellular Adhesion Molecule 1 ◽  
Necrosis Factor Alpha ◽  
Tnf Α ◽  
Factor Alpha ◽  
Blocking Antibodies ◽  
Selectin Binding

ABSTRACT Cryptococcal infections are often characterized by a paucity of leukocytes in the infected tissues. Previous research has shown that the capsular polysaccharide glucuronoxylomannan (GXM) inhibits leukocyte migration. In this study we investigated whether the capsular polysaccharide GXM affects the migration of neutrophils (polymorphonuclear leukocytes [PMN]) through the endothelium by interfering with adhesion in a static adhesion model. Pretreatment of PMN with GXM inhibited PMN adhesion to tumor necrosis factor alpha (TNF-α)-stimulated endothelium up to 44%. Treatment of TNF-α-stimulated endothelium with GXM led to a 27% decrease in PMN adhesion. GXM treatment of both PMN and endothelium did not have an additive inhibitory effect. We demonstrated that GXM-induced L-selectin shedding does not play an important role in the detected inhibition of adhesion. L-selectin was still present on PMN in sufficient amounts after GXM treatment, since it could be further inhibited by blocking antibodies. Furthermore, blocking of GXM-related L-selectin shedding did not abolish the GXM-related inhibition of adhesion. GXM most likely exerts its effect on PMN by interfering with E-selectin-mediated binding. The use of blocking monoclonal antibodies against E-selectin, which was shown to decrease adhesion in the absence of GXM, did not cause additive inhibition of PMN adhesion after GXM pretreatment. The use of blocking antibodies also demonstrated that the inhibiting effect found after GXM treatment of endothelium probably involves interference with both intercellular adhesion molecule-1 and E-selectin binding.

Recombinant PfEMP1 peptide inhibits and reverses cytoadherence of clinical Plasmodium falciparum isolates in vivo

Blood ◽  
2003 ◽  
Vol 101 (1) ◽  
pp. 331-337 ◽  
Author(s):  
Bryan G. Yipp ◽  
Dror I. Baruch ◽  
Ciaran Brady ◽  
Allan G. Murray ◽  
Sornchai Looareesuwan ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Severe Combined Immunodeficiency ◽  
Inhibitory Effect ◽  
Intercellular Adhesion Molecule ◽  
Skin Grafts ◽  
Intercellular Adhesion Molecule 1 ◽  
Recombinant Peptide ◽  
Tnf Α

Abstract The parasite ligand Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) and host endothelial receptors represent potential targets for antiadhesive therapy for cytoadherence. In the present study, the major host receptor CD36 was targeted in vitro and in vivo with a recombinant peptide, PpMC-179, corresponding to the minimal CD36-binding domain from the cysteine-rich interdomain region 1 (CIDR1) within the MCvar1 PfEMP1. The in vitro inhibitory effect of PpMC-179 on human dermal microvascular endothelial cells (HDMECs) expressing multiple relevant adhesion molecules was investigated using a parallel-plate flow chamber. Pretreatment of endothelial monolayers with PpMC-179 (2 μM) inhibited the adhesion of infected erythrocytes (IRBCs) from all clinical isolates tested by 84.4% on resting and 62.8% on tumor necrosis factor α (TNF-α)–stimulated monolayers. Adhesion to stimulated cells was further inhibited (90.4%) when PpMC-179 was administered with an inhibitory anti–intercellular adhesion molecule 1 (ICAM-1) monoclonal antibody 84H10 (5 μg/mL). To determine the in vivo effectiveness of PpMC-179, we used a human/severe combined immunodeficiency (SCID) mouse chimeric model that allowed direct visualization of cytoadherence on intact human microvasculature. In unstimulated skin grafts, PpMC-179 inhibited adhesion by 86.3% and by 84.6% in TNF-α–stimulated skin grafts. More importantly, PpMC-179 administration resulted in the detachment of already adherent IRBCs by 80.7% and 83.3% on resting and stimulated skin grafts, respectively. The antiadhesive effect of PpMC-179 was rapid and sustained in vivo for at least 30 minutes. Our data indicate that targeting cytoadhesion in vivo is feasible and may offer a rapid antimalarial therapy.

scholarly journals A Purified Capsular Polysaccharide Markedly Inhibits Inflammatory Response during Endotoxic Shock

2012 ◽  
Vol 81 (1) ◽  
pp. 90-98 ◽  
Author(s):  
M. Piccioni ◽  
C. Monari ◽  
S. Kenno ◽  
E. Pericolini ◽  
E. Gabrielli ◽  
...  
Keyword(s):  
Plasma Levels ◽  
Capsular Polysaccharide ◽  
Endotoxic Shock ◽  
Experimental System ◽  
Inhibitory Effect ◽  
Necrosis Factor Alpha ◽  
Content Type ◽  
Tnf Α ◽  
Factor Alpha

Capsular material of the opportunistic fungusCryptococcus neoformansis composed mainly of a polysaccharide named glucuronoxylomannan (GXM). In this study, the effects of GXM were analyzed in anin vivoexperimental system of lipopolysaccharide (LPS)-induced shock. Endotoxic shock was induced in mice by a single intraperitoneal injection of LPS fromEscherichia coli. GXM treatment reduced the mortality of mice at early stages. Mice treated with LPS alone showed markedly increased plasma levels of tumor necrosis factor alpha (TNF-α), interleukin-1β (IL-1β), and IL-6, whereas mice that were also treated with GXM showed significantly lower plasma levels of these cytokines. This effect was related to a marked suppression of Akt and IκBα activation. Importantly, the inhibitory effect of GXM on proinflammatory cytokine secretion was reproduced by treatment with wortmannin, an inhibitor of the Akt transcription pathway. Our results indicate that GXM has a beneficial effect on endotoxic shock, resulting in a significant increase in the rate of survival by dampening the hyperinflammatory response.

scholarly journals Expression of Tumor Necrosis Factor-Alpha and Intercellular Adhesion Molecule-1 after Focal Cerebral Ischemia in Interleukin-1β Converting Enzyme Deficient Mice

1999 ◽  
Vol 19 (10) ◽  
pp. 1109-1117 ◽  
Author(s):  
Guo-Yuan Yang ◽  
Gerald P. Schielke ◽  
Chao Gong ◽  
Ying Mao ◽  
Hai-Liang Ge ◽  
...  
Keyword(s):  
Cerebral Ischemia ◽  
Focal Cerebral Ischemia ◽  
Intercellular Adhesion Molecule ◽  
Wild Type ◽  
Intercellular Adhesion Molecule 1 ◽  
Necrosis Factor Alpha ◽  
Ipsilateral Hemisphere ◽  
Ischemic Brain ◽  
Tnf Α ◽  
Factor Alpha

Interleukin-1β (IL-1β) is expressed after cerebral ischemia and blocking its action reduces subsequent ischemic brain injury. However, the mechanisms by which IL-1β affects ischemic brain are not understood. To investigate the role of IL-1β in regulation of tumor necrosis factor-alpha (TNF-α) and intercellular adhesion molecule-1 (ICAM-1) during focal cerebral ischemia, the authors studied mutant mice deficient in the IL-1 converting enzyme (ICE) gene (ICE knockout [KO] mice). Ninety-four adult male ICE KO and wild-type mice underwent 3, 6, 12, and 24 hours of permanent middle cerebral artery occlusion using the suture method. Expression of TNF-α and ICAM-1 protein in ischemic brain was examined using immunohistochemistry and Western blot analysis. Neither ICE KO nor wild-type mice had significant differences in CBF and body temperature measurements during the ischemic procedure. TNF-α expression increased in the ipsilateral hemisphere after 3 hours of occlusion, peaked at 12 hours and decreased at 24 hours of ischemia in both ICE KO and wild-type mice. ICAM-1 immunohistochemistry showed that the number of ICAM-1–positive vessels in the ischemic hemisphere was reduced in ICE KO mice ( P < .05). Western blot analysis showed that ICAM-1 protein expression was significantly attenuated in the ipsilateral hemisphere in the ICE KO mice, which paralleled the immunohistochemistry results, The authors' results indicate that TNF-α expression is increased in both ICE KO and wild-type mice suggesting that TNF-α expression is not related to or upregulated by IL-1β. ICAM-1 expression is significantly reduced in the ICE KO mice suggesting that IL-1β plays an important role in the upregulation of adhesion molecules during focal cerebral ischemia.

Expression and self-regulatory function of cardiac interleukin-6 during endotoxemia

2000 ◽  
Vol 279 (5) ◽  
pp. H2241-H2248 ◽  
Author(s):  
Hiroshi Saito ◽  
Cam Patterson ◽  
Zhaoyong Hu ◽  
Marschall S. Runge ◽  
Ulka Tipnis ◽  
...  
Keyword(s):  
Feedback Mechanism ◽  
Intercellular Adhesion Molecule ◽  
Regulatory Function ◽  
Heart Cells ◽  
Intercellular Adhesion Molecule 1 ◽  
Negative Feedback Mechanism ◽  
Proinflammatory Mediators ◽  
Tnf Α

Interleukin (IL)-6 reportedly has negative inotropic and hypertrophic effects on the heart. Here, we describe endotoxin-induced IL-6 in the heart that has not previously been well characterized. An intraperitoneal injection of a bacterial lipopolysaccharide into C57BL/6 mice induced IL-6 mRNA in the heart more strongly than in any other tissue examined. Induction of mRNA for two proinflammatory cytokines, IL-1β and tumor necrosis factor (TNF)-α, occurred rapidly before the induction of IL-6 mRNA and protein. Although stimulation of isolated rat neonatal myocardial cells with IL-1β or TNF-α induced IL-6 mRNA in vitro, nonmyocardial heart cells produced higher levels of IL-6 mRNA upon stimulation with IL-1β. In situ hybridization and immunohistochemical analyses localized the IL-6 expression primarily in nonmyocardial cells in vivo. Endotoxin-induced expression of cardiac IL-1β, TNF-α, and intercellular adhesion molecule 1 was augmented in IL-6-deficient mice compared with control mice. Thus cardiac IL-6, expressed mainly by nonmyocardial cells via IL-1β action during endotoxemia, is likely to suppress expression of proinflammatory mediators and to regulate itself via a negative feedback mechanism.

scholarly journals Suppression of tumor necrosis factor-alpha-induced neutrophil adherence responses by essential oils

2003 ◽  
Vol 12 (6) ◽  
pp. 323-328 ◽  
Author(s):  
Shigeru Abe ◽  
Naho Maruyama ◽  
Kazumi Hayama ◽  
Hiroko Ishibashi ◽  
Shigeharu Inoue ◽  
...  
Keyword(s):  
Essential Oils ◽  
Tumor Necrosis ◽  
Neutrophil Activation ◽  
Necrosis Factor Alpha ◽  
Tnf Α ◽  
Neutrophil Adherence ◽  
Factor Alpha ◽  
Anti Inflammatory ◽  
Necrosis Factor

Background:In aromatherapy, essential oils are used as anti-inflammatory remedies, but experimental studies on their action mechanisms are very limited.Aims:To assess their anti-inflammatory activities, effects of essential oils on neutrophil activation were examinedin vitro.Methods:Neutrophil activation was measured by tumor necrosis factor-alpha (TNF-α)-induced adherence reaction of human peripheral neutrophils.Results:All essential oils tested at 0.1% concentration suppressed TNF-α-induced neutrophil adherence, and, in particular, lemongrass, geranium and spearmint oils clearly lowered the reaction even at 0.0125%. Similar inhibitory activities for the neutrophil adherence were obtained by their major constituent terpenoids: citral, geraniol, citronellol and carvone. In contrast, very popular essential oils, tea tree oil and lavender oil, did not display the inhibitory activity at the concentration.Conclusion:Thus, some essential oils used as anti-inflammatory remedies suppress neutrophil activation by TNF-α at a low concentration (0.0125-0.025%)in vitro.

scholarly journals Anti-Inflammatory Effects of Fucoxanthinol in LPS-Induced RAW264.7 Cells through the NAAA-PEA Pathway

Marine Drugs ◽  
2020 ◽  
Vol 18 (4) ◽  
pp. 222 ◽  
Author(s):  
Wenhui Jin ◽  
Longhe Yang ◽  
Zhiwei Yi ◽  
Hua Fang ◽  
Weizhu Chen ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Inhibitory Effect ◽  
Inflammatory Factors ◽  
Lipid Mediator ◽  
Peroxisome Proliferator ◽  
Necrosis Factor Alpha ◽  
Peroxisome Proliferator Activated Receptor ◽  
Tnf Α ◽  
Anti Inflammatory

Palmitoylethanolamide (PEA) is an endogenous lipid mediator with powerful anti-inflammatory and analgesic functions. PEA can be hydrolyzed by a lysosomal enzyme N-acylethanolamine acid amidase (NAAA), which is highly expressed in macrophages and other immune cells. The pharmacological inhibition of NAAA activity is a potential therapeutic strategy for inflammation-related diseases. Fucoxanthinol (FXOH) is a marine carotenoid from brown seaweeds with various beneficial effects. However, the anti-inflammatory effects and mechanism of action of FXOH in lipopolysaccharide (LPS)-stimulated macrophages remain unclear. This study aimed to explore the role of FXOH in the NAAA–PEA pathway and the anti-inflammatory effects based on this mechanism. In vitro results showed that FXOH can directly bind to the active site of NAAA protein and specifically inhibit the activity of NAAA enzyme. In an LPS-induced inflammatory model in macrophages, FXOH pretreatment significantly reversed the LPS-induced downregulation of PEA levels. FXOH also substantially attenuated the mRNA expression of inflammatory factors, including inducible nitric oxide synthase (iNOS), interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α), and markedly reduced the production of TNF-α, IL-6, IL-1β, and nitric oxide (NO). Moreover, the inhibitory effect of FXOH on NO induction was significantly abolished by the peroxisome proliferator-activated receptor α (PPAR-α) inhibitor GW6471. All these findings demonstrated that FXOH can prevent LPS-induced inflammation in macrophages, and its mechanisms may be associated with the regulation of the NAAA-PEA-PPAR-α pathway.

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