scholarly journals Infection of Human Endothelial Cells with Spotted Fever Group Rickettsiae Stimulates Cyclooxygenase 2 Expression and Release of Vasoactive Prostaglandins

2006 ◽  
Vol 74 (9) ◽  
pp. 5067-5074 ◽  
Author(s):  
Elena Rydkina ◽  
Abha Sahni ◽  
Raymond B. Baggs ◽  
David J. Silverman ◽  
Sanjeev K. Sahni
Keyword(s):  
Endothelial Cells ◽  
De Novo ◽  
Inflammatory Responses ◽  
Ex Vivo ◽  
Spotted Fever ◽  
Mitogen Activated Protein Kinase ◽  
Spotted Fever Group ◽  
Human Endothelial Cells ◽  
Cox Inhibitor ◽  
Cox 2

ABSTRACTRickettsiae, a diverse group of obligately intracellular gram-negative bacteria, include etiologic agents of the spotted fever and typhus groups of diseases. Rocky Mountain spotted fever and boutonneuse fever, due toRickettsia rickettsiiandR. conorii, respectively, are characterized by widespread infection of the vascular endothelium, microvascular injury, and vasculitis. Cultured human endothelial cells (EC) are highly susceptible to infection and respond by altering the expression of adhesion molecules, regulatory cytokines, and the antioxidant enzyme heme oxygenase (HO). In the vasculature, HO regulates the cyclooxygenase (COX) enzymes, among which the inducible isozyme COX-2 facilitates the synthesis of prostaglandins (PGs). Using in vitro and ex vivo models of infection, we demonstrate here thatR. rickettsiiinfection of human EC causes robust induction of COX-2 mRNA and protein expression but has no apparent effect on the constitutive COX-1 isoform. Cells infected with viable rickettsiae consistently displayed significantly increased secretion of 6-keto-PGF1αand PGE2.R. rickettsii-induced COX-2 was sensitive to inhibitors of de novo transcription and the pyridinylimidazole-based compound SB 203580, suggesting that this transcriptional host cell response involves signaling through p38 mitogen-activated protein kinase. PG production by infected cells was abrogated by NS 398 (a selective COX-2 inhibitor) and indomethacin (a pan-COX inhibitor). Immunohistochemical staining of sections of infected umbilical cords and corresponding uninfected controls revealed comparatively more intense and abundant staining for COX-2 in infected endothelia. Induction of the endothelial COX-2 system and the resultant enhanced release of vasoactive PGs may contribute to the regulation of inflammatory responses and vascular permeability changes during spotted fever rickettsioses.

scholarly journals Cyclooxygenase-2 Glycosylation Is Affected by Peroxynitrite in Endothelial Cells: Impact on Enzyme Activity and Degradation

Antioxidants ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 496
Author(s):  
Sonia Eligini ◽  
Susanna Colli ◽  
Aida Habib ◽  
Giancarlo Aldini ◽  
Alessandra Altomare ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
De Novo ◽  
Cyclooxygenase 2 ◽  
Nitric Oxide Donors ◽  
Metabolic Labeling ◽  
Dependent Manner ◽  
De Novo Synthesis ◽  
Human Endothelial Cells ◽  
Prolonged Incubation ◽  
Cox 2

The exposure of human endothelial cells to 3-morpholinosydnonimine (SIN-1) induced the expression of cyclooxygenase-2 (COX-2) in a dose- and time-dependent manner. Interestingly, after a prolonged incubation (>8 h) several proteoforms were visualized by Western blot, corresponding to different states of glycosylation of the protein. This effect was specific for SIN-1 that generates peroxynitrite and it was not detected with other nitric oxide-donors. Metabolic labeling experiments using 35S or cycloheximide suggested that the formation of hypoglycosylated COX-2 was dependent on de novo synthesis of the protein rather than the deglycosylation of the native protein. Moreover, SIN-1 reduced the activity of the hexokinase, the enzyme responsible for the first step of glycolysis. The hypoglycosylated COX-2 induced by SIN-1 showed a reduced capacity to generate prostaglandins and the activity was only partially recovered after immunoprecipitation. Finally, hypoglycosylated COX-2 showed a more rapid rate of degradation compared to COX-2 induced by IL-1α and an alteration in the localization with an accumulation mainly detected in the nuclear membrane. Our results have important implication to understand the effect of peroxynitrite on COX-2 expression and activity, and they may help to identify new pharmacological tools direct to increase COX-2 degradation or to inhibit its activity.

scholarly journals Monosodium Urate Microcrystals Induce Cyclooxygenase-2 in Human Monocytes

Blood ◽  
1998 ◽  
Vol 91 (5) ◽  
pp. 1769-1776 ◽  
Author(s):  
Marc Pouliot ◽  
Michael J. James ◽  
Shaun R. McColl ◽  
Paul H. Naccache ◽  
Leslie G. Cleland
Keyword(s):  
De Novo ◽  
Inflammatory Responses ◽  
Gouty Arthritis ◽  
Calcium Pyrophosphate ◽  
Mononuclear Phagocyte ◽  
Mononuclear Phagocytes ◽  
Mitogen Activated Protein Kinase ◽  
Calcium Pyrophosphate Dihydrate ◽  
Monosodium Urate ◽  
Cox 2

Abstract The formation and deposition of monosodium urate (MSU) microcrystals in articular and periarticular tissues is the causative agent of acute or chronic inflammatory responses known as gouty arthritis. Mononuclear phagocyte activation is involved in early triggering events of gout attacks. Because stimulated mononuclear phagocytes can constitute an important source of the inducible isoform of cyclooxygenase (COX-2), we evaluated the effects that proinflammatory microcrystals might have on COX-2 protein expression in crystal-stimulated monocytes. We found that MSU crystals, but not calcium pyrophosphate dihydrate (CPPD) crystals, induced COX-2, which correlated with the synthesis of prostaglandin E2 (PGE2) and thromboxane A2(TXA2). Crystal-induced de novo synthesis of COX-2 was dependent on transcriptional and translational events. Inhibition of tyrosine phosphorylation, by herbimycin A, blocked crystal-induced COX-2. Similarly, an inhibitor of the p38 mitogen-activated protein kinase, SB 203580, inhibited the stimulation of COX-2. Colchicine inhibited crystal-induced COX-2. In all cases, prostanoid synthesis was concomitantly inhibited. Taken together, these results implicate COX-2 in the development of MSU-induced inflammation.

scholarly journals Monosodium Urate Microcrystals Induce Cyclooxygenase-2 in Human Monocytes

Blood ◽  
1998 ◽  
Vol 91 (5) ◽  
pp. 1769-1776
Author(s):  
Marc Pouliot ◽  
Michael J. James ◽  
Shaun R. McColl ◽  
Paul H. Naccache ◽  
Leslie G. Cleland
Keyword(s):  
De Novo ◽  
Inflammatory Responses ◽  
Gouty Arthritis ◽  
Calcium Pyrophosphate ◽  
Mononuclear Phagocyte ◽  
Mononuclear Phagocytes ◽  
Mitogen Activated Protein Kinase ◽  
Calcium Pyrophosphate Dihydrate ◽  
Monosodium Urate ◽  
Cox 2

The formation and deposition of monosodium urate (MSU) microcrystals in articular and periarticular tissues is the causative agent of acute or chronic inflammatory responses known as gouty arthritis. Mononuclear phagocyte activation is involved in early triggering events of gout attacks. Because stimulated mononuclear phagocytes can constitute an important source of the inducible isoform of cyclooxygenase (COX-2), we evaluated the effects that proinflammatory microcrystals might have on COX-2 protein expression in crystal-stimulated monocytes. We found that MSU crystals, but not calcium pyrophosphate dihydrate (CPPD) crystals, induced COX-2, which correlated with the synthesis of prostaglandin E2 (PGE2) and thromboxane A2(TXA2). Crystal-induced de novo synthesis of COX-2 was dependent on transcriptional and translational events. Inhibition of tyrosine phosphorylation, by herbimycin A, blocked crystal-induced COX-2. Similarly, an inhibitor of the p38 mitogen-activated protein kinase, SB 203580, inhibited the stimulation of COX-2. Colchicine inhibited crystal-induced COX-2. In all cases, prostanoid synthesis was concomitantly inhibited. Taken together, these results implicate COX-2 in the development of MSU-induced inflammation.

Platelets Stimulate Thromboplastin Synthesis in Human Endothelial Cells

1983 ◽  
Vol 49 (02) ◽  
pp. 069-072 ◽  
Author(s):  
U L H Johnsen ◽  
T Lyberg ◽  
K S Galdal ◽  
H Prydz
Keyword(s):  
Endothelial Cells ◽  
De Novo ◽  
Umbilical Vein ◽  
Time Dependent ◽  
De Novo Synthesis ◽  
Human Endothelial Cells ◽  
Tumor Promotor ◽  
Coagulation Assay ◽  
Platelet Aggregates ◽  
Umbilical Vein Endothelial Cells

SummaryHuman umbilical vein endothelial cells in culture synthesize thromboplastin upon stimulation with phytohaemagglutinin (PHA) or the tumor promotor 12-O-tetradecanoyl-phorbol-13-acetate (TPA). The thromboplastin activity is further strongly enhanced in a time dependent reaction by the presence of gel-filtered platelets or platelet aggregates. This effect was demonstrable at platelet concentrations lower than those normally found in plasma, it may thus be of pathophysiological relevance. The thromboplastin activity increased with increasing number of platelets added. Cycloheximide inhibited the increase, suggesting that de novo synthesis of the protein component of thromboplastin, apoprotein III, is necessary.When care was taken to remove monocytes no thromboplastin activity and no apoprotein HI antigen could be demonstrated in suspensions of gel-filtered platelets, platelets aggregated with thrombin or homogenized platelets when studied with a coagulation assay and an antibody neutralization technique.

scholarly journals Quantitative Analyses of Variations in the Injury of Endothelial Cells Elicited by 11 Isolates of Rickettsia rickettsii

2001 ◽  
Vol 8 (4) ◽  
pp. 788-796 ◽  
Author(s):  
Marina E. Eremeeva ◽  
Gregory A. Dasch ◽  
David J. Silverman
Keyword(s):  
North Carolina ◽  
Endothelial Cells ◽  
Reduced Glutathione ◽  
Spotted Fever ◽  
Ixodid Ticks ◽  
Spotted Fever Group ◽  
Cellular Injury ◽  
Rickettsia Rickettsii ◽  
Cytopathic Effects ◽  
Group I

ABSTRACT Eleven isolates of spotted fever group rickettsiae from the blood of patients or ixodid ticks from North and South America were characterized. All isolates were identified as Rickettsia rickettsii using restriction fragment length polymorphism analysis of a 532-bp rOmpA gene fragment obtained by PCR. The ability of the R. rickettsii isolates to elicit cytopathic effects and parameters of oxidative injury were examined in cultured human EA.hy 926 endothelial cells. Cytopathic effects were determined by direct observation of infected cultures, by measuring the release of cytoplasmic lactate dehydrogenase (LDH), and by determination of intracellular pools of peroxide and reduced glutathione. Four biotypes of R. rickettsii were defined. Group I included two highly cytopathic isolates from Montana, Bitterroot and Sheila Smith, and three isolates from Maryland, North Carolina, and Brazil. These isolates rapidly damaged cells, released large amounts of cytoplasmic LDH, caused accumulation of intracellular peroxide, and depleted intracellular pools of reduced glutathione. Group II contained three isolates, two from Montana, Hlp#2 and Lost Horse Canyon, and an isolate from Colombia, which were similar to group I but caused either lower responses in LDH release or smaller changes in intracellular peroxide levels. The group III isolates, Sawtooth from Montana and 84JG from North Carolina, caused lower cellular injury by all measures. Group IV isolate Price T from Montana was the least cytopathic and caused minimal alterations of all parameters measured. Understanding the molecular basis for the varied cellular injury caused by different isolates of R. rickettsii may contribute to improved treatment of Rocky Mountain spotted fever and to the rapid identification of those isolates which are more likely to cause fulminant disease.

scholarly journals Significant Growth by Rickettsia Species within Human Macrophage-Like Cells Is a Phenotype Correlated with the Ability to Cause Disease in Mammals

Pathogens ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 228
Author(s):  
M. Nathan Kristof ◽  
Paige E. Allen ◽  
Lane D. Yutzy ◽  
Brandon Thibodaux ◽  
Christopher D. Paddock ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Spotted Fever ◽  
Growth Characteristic ◽  
Human Macrophage ◽  
Rickettsia Conorii ◽  
Spotted Fever Group ◽  
Rocky Mountain Spotted Fever ◽  
Phagocytic Cells ◽  
Pathogenic Potential ◽  
Rickettsia Species

Rickettsia are significant sources of tick-borne diseases in humans worldwide. In North America, two species in the spotted fever group of Rickettsia have been conclusively associated with disease of humans: Rickettsia rickettsii, the causative agent of Rocky Mountain spotted fever, and Rickettsia parkeri, the cause of R. parkeri rickettsiosis. Previous work in our lab demonstrated non-endothelial parasitism by another pathogenic SFG Rickettsia species, Rickettsia conorii, within THP-1-derived macrophages, and we have hypothesized that this growth characteristic may be an underappreciated aspect of rickettsial pathogenesis in mammalian hosts. In this work, we demonstrated that multiple other recognized human pathogenic species of Rickettsia, including R. rickettsii, R. parkeri, Rickettsia africae, and Rickettsiaakari can grow within target endothelial cells as well as within PMA-differentiated THP-1 cells. In contrast, Rickettsia bellii, a Rickettsia species not associated with disease of humans, and R. rickettsii strain Iowa, an avirulent derivative of pathogenic R. rickettsii, could invade both cell types but proliferate only within endothelial cells. Further analysis revealed that similar to previous studies on R. conorii, other recognized pathogenic Rickettsia species could grow within the cytosol of THP-1-derived macrophages and avoided localization with two different markers of lysosomal compartments; LAMP-2 and cathepsin D. R. bellii, on the other hand, demonstrated significant co-localization with lysosomal compartments. Collectively, these findings suggest that the ability of pathogenic rickettsial species to establish a niche within macrophage-like cells could be an important factor in their ability to cause disease in mammals. These findings also suggest that analysis of growth within mammalian phagocytic cells may be useful to predict the pathogenic potential of newly isolated and identified Rickettsia species.

scholarly journals Carbon dioxide inhibits COVID-19-type proinflammatory responses through extracellular signal-regulated kinases 1 and 2, novel carbon dioxide sensors

2021 ◽  
Author(s):  
Hanna Galganska ◽  
Wieslawa Jarmuszkiewicz ◽  
Lukasz Galganski
Keyword(s):  
Carbon Dioxide ◽  
Endothelial Cells ◽  
Inflammatory Responses ◽  
Mitogen Activated Protein Kinase ◽  
Extracellular Signal ◽  
Mapk Signalling ◽  
Mitogen Activated Protein ◽  
Proinflammatory Responses ◽  
Factor Α ◽  
Preclinical And Clinical Studies

AbstractMitogen-activated protein kinase (MAPK) signalling pathways are crucial for developmental processes, oncogenesis, and inflammation, including the production of proinflammatory cytokines caused by reactive oxygen species and upon severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. There are no drugs that can effectively prevent excessive inflammatory responses in endothelial cells in the lungs, heart, brain, and kidneys, which are considered the main causes of severe coronavirus disease 2019 (COVID-19). In this work, we demonstrate that human MAPKs, i.e. extracellular signal-regulated kinases 1 and 2 (ERK1/2), are CO2 sensors and CO2 is an efficient anti-inflammatory compound that exerts its effects through inactivating ERK1/2 in cultured endothelial cells when the CO2 concentration is elevated. CO2 is a potent inhibitor of cellular proinflammatory responses caused by H2O2 or the receptor-binding domain (RBD) of the spike protein of SARS-CoV-2. ERK1/2 activated by the combined action of RBD and cytokines crucial for the development of severe COVID-19, i.e. interferon-gamma (IFNγ) and tumour necrosis factor-α (TNFα), are more effectively inactivated by CO2 than by dexamethasone or acetylsalicylic acid in human bronchial epithelial cells. Previously, many preclinical and clinical studies showed that the transient application of 5–8% CO2 is safe and effective in the treatment of many diseases. Therefore, our research indicates that CO2 may be used for the treatment of COVID-19 as well as the modification of hundreds of cellular pathways.

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