Substrate-inactivated cyclooxygenase-2 is disposed of by exosomes through the ER–Golgi pathway

2018 ◽  
Vol 475 (19) ◽  
pp. 3141-3151 ◽  
Author(s):  
Esraa Saadi ◽  
Sharon Tal ◽  
Liza Barki-Harrington
Keyword(s):  
Enzymatic Activity ◽  
Prolonged Exposure ◽  
Cyclooxygenase 2 ◽  
Target Cells ◽  
Continuous Exposure ◽  
Suicide Inactivation ◽  
Mediators Of Inflammation ◽  
Inflammatory Stimuli ◽  
Cox 2 ◽  
Activity Dependent

Catalysis of arachidonic acid (AA) by cyclooxygenase-2 (COX-2) gives rise to a single product that serves as a precursor for all prostaglandins, which are central mediators of inflammation. Rapid up-regulation of COX-2 expression in response to pro-inflammatory stimuli is a well-characterized means of generating the large pool of prostaglandins necessary for inflammation. However, an efficient inflammatory process must also terminate rapidly and thus requires cessation of COX-2 enzymatic activity and removal of excess protein from the cell. Previous studies showed that COX-2 that has not been exposed to AA (‘naive’) degrades in the cellular proteasome. However, continuous exposure to AA induces suicide inactivation of COX-2 and its elimination no longer occurs in neither the proteasomal nor lysosomal machineries. In the present study, we show that either overexpressed or endogenously induced COX-2 is secreted via exosomes through the endoplasmic reticulum–Golgi pathway. We further find that excretion of COX-2 is significantly enhanced by prolonged exposure to AA. Genetic or chemical inhibition of COX-2 enzymatic activity has no effect on its secretion in the absence of substrate, but prevents the additional activity-dependent secretion. Finally, transfer of COX-2 to target cells only occurs in the absence of AA stimulation. Together, these results suggest that exosomal secretion of AA-activated COX-2 constitutes a means to remove damaged inactive COX-2 from the cell.

253 GENE SILENCING OF CYCLOOXYGENASE-2 mRNA BY RNA INTERFERENCE IN BOVINE CUMULUS - GRANULOSA CELLS

2006 ◽  
Vol 18 (2) ◽  
pp. 234
Author(s):  
S.-I. Kobayashi ◽  
M. Sakatani ◽  
S. Kobayashi ◽  
K. Okuda ◽  
M. Takahashi
Keyword(s):  
Gene Expression ◽  
Gene Silencing ◽  
Mrna Expression ◽  
Culture Medium ◽  
Cyclooxygenase 2 ◽  
Target Cells ◽  
Specific Gene ◽  
Cox 2 ◽  
Sirna Group ◽  
Interference Rna

Recently, interference RNA (RNAi), inducing inhibition of the specific gene expression, attracted a lot of attention. Many researchers have reported that the 21-mer small interference RNA (siRNA) is introduced into target cells and then siRNA can suppress the gene expression. RNAi is a useful tool for functional analysis of specific genes. However, there is little information about RNAi for the analysis of gene function in reproductive physiology in ruminants. Thus, this study was aimed at evaluating RNAi for the analysis of cyclooxygenase-2 (Cox-2) mRNA expression in bovine cumulus-granulosa (CG) cells as well as prostaglandin F2� (PGF2�) production. We investigated both the effective concentration of Cox-2 siRNA and the effect of the introduction time of siRNA on Cox-2 mRNA expression. Bovine CG cells were collected at slaughterhouse and cultured in 4-well dishes. After the cells reached confluency, two experiments were conducted. In the present study, Cox-2 siRNA was simply added to culture medium with lipofectamine" 2000 (Invitrogen Japan K. K., Tokyo, Japan) as the transfection reagent. In experiment 1, the concentration of 0, 100, 250, and 500 pM of Cox-2 siRNA was introduced into the CG cells. After 24 h of introduction, the amount of mRNA expression for Cox-2 was measured by reverse transcription polymerase chain reaction (RT-PCR) and real-time PCR. In experiment 2, 250 pM siRNA for Cox-2 was introduced into CG cells for 0, 3, 6, 12, and 24 h. After culture, the amount of mRNA expression for Cox-2 was measured and the culture medium was collected to determine PGF2� concentration by enzyme immunoassay. The Cox-2 mRNA expression was not affected by 100 pM siRNA introduced into CG cells for 24 h, but 250 and 500 pM Cox-2 siRNA significantly reduced the Cox-2 mRNA expression (10% of that of the 0 pM siRNA group). Moreover, the suppressive effect of 250 pM siRNA was observed at 6 h after introduction (60% of that of the 0 pM siRNA group at 0 h) and the reduction of mRNA expression by RNAi became more obvious over 12 h (10% of that of the 0 pM siRNA group at 0 h). On the other hand, the PGF2� concentration in the culture medium was not significantly different at 12 h after siRNA introduction, however, the PGF2� concentration of the RNAi treatment group at 24 h was significantly lower than that of the 0 pM siRNA group at the same time point. These results suggest that gene silencing by Cox-2 siRNA is a means of analyzing the function and expression of specific genes in bovine CG cells. This study was supported by the Japan Society for the Promotion of Science for Young Scientists.

Contribution of stromal and epithelial cells to cyclooxygenase-2 (COX-2) activity in Barrett's esophagus

2001 ◽  
Vol 120 (5) ◽  
pp. A78-A79
Author(s):  
N BUTTAR ◽  
K WANG ◽  
M ANDERSON ◽  
L LUTZKE ◽  
K KRISHNADATH
Keyword(s):  
Epithelial Cells ◽  
Barrett’S Esophagus ◽  
Barrett's Esophagus ◽  
Cyclooxygenase 2 ◽  
Cox 2

Expressions of cyclooxygenase-2 (COX-2) and prostaglandin E receptors (EPs) in gallbladder carcinoma (GBca)-association with tumor progression

2001 ◽  
Vol 120 (5) ◽  
pp. A573-A573
Author(s):  
J SHODA ◽  
T ASANO ◽  
T KAWAMOTO ◽  
Y MATSUZAKI ◽  
N TANAKA ◽  
...  
Keyword(s):  
Tumor Progression ◽  
Gallbladder Carcinoma ◽  
Cyclooxygenase 2 ◽  
Prostaglandin E ◽  
Cox 2

Gastrin and cyclooxygenase-2 (COX-2) expression in Helicobacter pylori (Hp) infected gastric ulceration

2001 ◽  
Vol 120 (5) ◽  
pp. A727-A727
Author(s):  
S KONTUREK ◽  
P KONTUREK ◽  
W BIELANSKI ◽  
A DUDA ◽  
M ZUCHOWICZ ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Gastric Ulceration ◽  
Cyclooxygenase 2 ◽  
Cox 2

1008: Expression of Cyclooxygenase-2 (COX-2) in Human Renal Cell Carcinoma (RCCA)

2004 ◽  
Vol 171 (4S) ◽  
pp. 266-267
Author(s):  
Sean McLaughlin ◽  
Eric Wallen ◽  
William K. Funkhouser ◽  
Raj S. Pruthi
Keyword(s):  
Renal Cell Carcinoma ◽  
Cell Carcinoma ◽  
Renal Cell ◽  
Cyclooxygenase 2 ◽  
Human Renal Cell Carcinoma ◽  
Cox 2

Mikroglia und immunologische Mechanismen in der neuropsychiatrischen Forschung

2014 ◽  
Vol 33 (11) ◽  
pp. 761-770
Author(s):  
M. J. Schwarz ◽  
B. Leitner ◽  
E. Weidinger ◽  
N. Müller
Keyword(s):  
Prostaglandin E2 ◽  
Cyclooxygenase 2 ◽  
Cox 2

ZusammenfassungDie Psychoneuroimmunologie beschäftigt sich mit den Wechselwirkungen zwischen der (gesunden) Psyche, psychischen Störungen und dem Immunsystem. Inzwischen hat sich gezeigt, dass zumindest bei Subgruppen psychischer Störungen wie Schizophrenie und Depression ein entzündlicher Prozess bei der Pathogenese eine Rolle spielt. Da für Schizophrenie und Depression auf diesem Gebiet die meisten Befunde vorliegen, konzentriert sich diese Übersicht auf diese beiden Störungsbilder. Die differenzielle Aktivierung von Mikrogliazellen und Astrozyten als funktionelle Träger des Immunsystems im ZNS, trägt zur Typ-1/Typ-2-Inbalance bei. Das entzündliche Geschehen ist verbunden mit höherer Prostaglandin-E2 (PGE-2)-Produktion und erhöhter Cyclooxygenase-2 (COX-2)-Expression. Zunehmende Evidenz aus klinischen Studien mit COX-2-Inhibitoren weisen auf einen günstigen Effekt antiinflammatorischer Therapie bei Schizophrenie hin, speziell in frühen Stadien der Krankheit. Sowohl bei Depression als auch bei Schizophrenie ist die Vulnerabilitäts- Stress-Hypothese weitgehend akzeptiert. So zeigte sich z. B. dass – bei entsprechender genetischer Disposition – Stress im frühen Lebensalter oder Separationsstress mit einem Anstieg proinflammatorischer Zytokine einhergehen und zu einer Immunaktivierung führen. Die Interaktionen zwischen dem Immunsystem, Neurotransmittern und dem Tryptophan- Kynurenin-System sind entscheidende Komponenten für die Pathogenese von Stress und Depression. Eine antientzündliche Behandlung, z. B. mit dem COX-2-Inhibitor Celecoxib, zeigt antidepressive Effekte.

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