Key role for cyclooxygenase-2 in PGE2 and PGF2α receptor regulation and cerebral blood f low of the newborn

1997 ◽  
Vol 273 (4) ◽  
pp. R1283-R1290 ◽  
Author(s):  
Ding-You Li ◽  
Pierre Hardy ◽  
Daniel Abran ◽  
Ana-Katherine Martinez-Bermudez ◽  
Anne-Marie Guerguerian ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Receptor Agonist ◽  
Prostaglandin E ◽  
Receptor Density ◽  
Cerebral Vasculature ◽  
Newborn Brain ◽  
Cox Inhibitor ◽  
Newborn Pigs ◽  
Cox 2 ◽  
Cox 1

Ibuprofen, a cyclooxygenase (COX) inhibitor nonselective for either COX-1 or COX-2 isoform, upregulates cerebrovascular prostaglandin E2(PGE2) and PGF2α receptors in newborn pigs. COX-2 was shown to be the predominant form of COX and the main catalyst of prostaglandin synthesis in the newborn brain. We proceeded to establish direct evidence that COX-2-generated prostaglandins govern PGE2 and PGF2α receptor density and function in the cerebral vasculature of the newborn. Hence, we determined PGE2 and PGF2α receptor density and functions in brain vasculature by using newborn pigs treated with saline, ibuprofen, COX-1 inhibitor (valerylsalicylate), or COX-2 inhibitors (DUP-697 and NS-398). Newborn brain PGE2 and PGF2α concentrations were significantly reduced by ibuprofen, DUP-697, and NS-398 but not by valerylsalicylate. In newborn pigs treated with DUP-697, NS-398, and ibuprofen, PGE2 and PGF2α receptor densities in brain microvessels were increased to adult levels; there was also a significant increase in inositol 1,4,5-trisphosphate (IP3) production and cerebral vasoconstrictor effects of 17-phenyl trinor PGE2(EP1 receptor agonist), M&B-28767 (EP3 receptor agonist), PGF2α, and fenprostalene (PGF2αanalog). Treatment with ibuprofen or DUP-697 also increased the upper blood pressure limit of cerebral cortex and periventricular blood flow autoregulation from 85 to ≥125 mmHg (uppermost blood pressure studied). However, valerylsalicylate treatment did not affect cerebrovascular PGE2 and PGF2α receptors, IP3 production, or vasoconstrictor effects in newborn animals. These in vivo and in vitro observations indicate that COX-2 is mainly responsible for the regulation of PGE2 and PGF2α receptors and their functions in the newborn cerebral vasculature.

Cyclooxygenase-2 inhibition normalizes arterial blood pressure in CYP1A1-REN2 transgenic rats with inducible ANG II-dependent malignant hypertension

2006 ◽  
Vol 291 (3) ◽  
pp. F612-F618 ◽  
Author(s):  
Allison L. Opay ◽  
Cynthia R. Mouton ◽  
John J. Mullins ◽  
Kenneth D. Mitchell
Keyword(s):  
Blood Pressure ◽  
Renal Plasma Flow ◽  
Renal Hemodynamics ◽  
Malignant Hypertension ◽  
Hypertensive Rats ◽  
Transgenic Rats ◽  
Arterial Blood ◽  
Cox Inhibitor ◽  
Cox 2 ◽  
Cox 1

The present study was performed to determine the effects of cyclooxygenase (COX)-1 and COX-2 inhibition on blood pressure and renal hemodynamics in transgenic rats with inducible malignant hypertension [strain name: TGR(Cyp1a1Ren2)]. Male Cyp1a1-Ren2 rats ( n = 7) were fed a normal diet containing the aryl hydrocarbon, indole-3-carbinol (I3C; 0.3%), for 6–9 days to induce malignant hypertension. Mean arterial pressure (MAP) and renal hemodynamics were measured in pentobarbital sodium-anesthetized Cyp1a1-Ren2 rats during control conditions, following administration of the COX-2 inhibitor nimesulide (3 mg/kg iv), and following administration of the nonspecific COX inhibitor meclofenamate (5 mg/kg iv). Rats induced with I3C had higher MAP than noninduced rats ( n = 7; 188 ± 6 vs. 136 ± 4 mmHg, P < 0.01). There was no difference in renal plasma flow (RPF) or glomerular filtration rate (GFR) between induced and noninduced rats. Nimesulide elicited a larger decrease in MAP in hypertensive rats (188 ± 6 to 140 ± 8 mmHg, P < 0.01) than in normotensive rats (136 ± 4 to 113 ± 8 mmHg, P < 0.01). Additionally, nimesulide decreased GFR (0.9 ± 0.13 to 0.44 ± 0.05 ml·min−1·g−1, P < 0.05) and RPF (2.79 ± 0.27 to 1.35 ± 0.14 ml·min−1·g−1, P < 0.05) in hypertensive rats but did not alter GFR or RPF in normotensive rats. Meclofenamate further decreased MAP in hypertensive rats (to 115 ± 10 mmHg, P < 0.05) but did not decrease MAP in normotensive rats. Meclofenamate did not alter GFR or RPF in either group. These findings demonstrate that COX-1- and COX-2-derived prostanoids contribute importantly to the development of malignant hypertension in Cyp1a1-Ren2 transgenic rats. The data also indicate that COX-2-derived vasodilatory metabolites play an important role in the maintenance of RPF and GFR following induction of malignant hypertension in Cyp1a1-Ren2 transgenic rats.

scholarly journals ChTX induces oscillatory contraction in guinea pig trachea: role of cyclooxygenase-2 and PGE2

2003 ◽  
Vol 284 (6) ◽  
pp. L1045-L1054 ◽  
Author(s):  
Yukihiro Yagi ◽  
Masayoshi Kuwahara ◽  
Hirokazu Tsubone
Keyword(s):  
Guinea Pig ◽  
Prostaglandin E ◽  
Receptor Subtype ◽  
Phasic Contraction ◽  
Oscillatory Frequency ◽  
Cox Inhibitor ◽  
The Mean ◽  
Cox 2 ◽  
Cox 1

We examined the possible role of cyclooxygenase (COX) in charybdotoxin (ChTX)-induced oscillatory contraction in guinea pig trachea. Involvement of prostaglandin E2 (PGE2) in ChTX-induced oscillatory contraction was also investigated. ChTX (100 nM) induced oscillatory contraction in guinea pig trachea. The mean oscillatory frequency induced by ChTX was 10.7 ± 0.8 counts/h. Maximum and minimum tensions within ChTX-induced oscillatory contractions were 68.4 ± 1.8 and 14.3 ± 1.7% compared with K+ (72.7 mM) contractions. ChTX-induced oscillatory contraction was completely inhibited by indomethacin, a nonselective COX inhibitor. Valeryl salicylate, a selective COX-1 inhibitor, did not significantly inhibit this contraction, whereas N-(2-cyclohexyloxy-4-nitro-phenyl)-methanesulfonamide, a selective COX-2 inhibitor, abolished this contraction. Exogenously applied arachidonic acid enhanced ChTX-induced oscillatory contraction. SC-51322, a selective PGE receptor subtype EP1 antagonist, significantly inhibited ChTX-induced oscillatory contraction. Exogenously applied PGE2 induced only a slight phasic contraction in guinea pig trachea, but PGE2 induced strong oscillatory contraction after pretreatment with indomethacin and ChTX. Moreover, ChTX time-dependently stimulated PGE2 generation. These results suggest that ChTX specifically activates COX-2 and stimulates PGE2 production and that ChTX-induced oscillatory contraction in guinea pig trachea is mediated by activation of EP1 receptor.

Cyclooxygenase-2 plays a significant role in regulating the tone of the fetal lamb ductus arteriosus

1999 ◽  
Vol 276 (3) ◽  
pp. R913-R921 ◽  
Author(s):  
Ronald I. Clyman ◽  
Pierre Hardy ◽  
Nahid Waleh ◽  
Yao Qi Chen ◽  
Françoise Mauray ◽  
...  
Keyword(s):  
Significant Role ◽  
Ductus Arteriosus ◽  
Late Gestation ◽  
Relative Contribution ◽  
Cox Inhibitor ◽  
Fetal Lamb ◽  
Cox 2 ◽  
Cox 2 Inhibitors ◽  
Cox 1

Nonselective cyclooxygenase (COX) inhibitors are potent tocolytic agents but have adverse effects on the fetal ductus arteriosus. We hypothesized that COX-2 inhibitors may not affect the ductus if the predominant COX isoform is COX-1. To examine this hypothesis, we used ductus arteriosus obtained from late-gestation fetal lambs. In contrast to our hypothesis, fetal lamb ductus arteriosus expressed both COX-1- and COX-2-immunoreactive protein (by Western analysis). Although COX-1 was found in both endothelial and smooth muscle cells, COX-2 was found only in the endothelial cells lining the ductus lumen (by immunohistochemistry). The relative contribution of COX-1 and COX-2 to PGE2 synthesis was consistent with the immunohistochemical results: in the intact ductus, PGE2 formation was catalyzed by both COX-1 and COX-2 in equivalent proportions; in the endothelium-denuded ductus, COX-2 no longer played a significant role in PGE2 synthesis. NS-398, a selective inhibitor of COX-2, was 66% as effective as the selective COX-1 inhibitor valeryl salicylate and the nonselective COX inhibitor indomethacin in causing contraction of the ductus in vitro. At this time, caution should be used when recommending COX-2 inhibitors for use in pregnant women.

Cyclooxygenases and prostaglandin E synthases in preimplantation mouse embryos

Zygote ◽  
2005 ◽  
Vol 13 (2) ◽  
pp. 103-108 ◽  
Author(s):  
Hui-Ning Tan ◽  
Ying Liu ◽  
Hong-Lu Diao ◽  
Zeng-Ming Yang
Keyword(s):  
Blastocyst Stage ◽  
Mouse Embryos ◽  
Prostaglandin E ◽  
Female Reproduction ◽  
Low Level ◽  
Preimplantation Mouse Embryos ◽  
Preimplantation Mouse ◽  
Cox 2 ◽  
High Level ◽  
Cox 1

Prostaglandin E2 (PGE2) is shown to be essential for female reproduction. Cyclooxygenase (COX) is a rate-limiting enzyme in prostaglandin synthesis from arachidonic acid and exists in two isoforms: COX-1 and COX-2. Prostaglandin E synthase (PGES) is a terminal prostanoid synthase and can catalyse the isomerization of the COX product PGH2 to PGE2, including microsomal PGES-1 (mPGES-1), cytosolic PGES (cPGES) and mPGES-2. This study examined the protein expression of COX-1, COX-2, mPGES-1, cPGES and mPGES-2 in preimplantation mouse embryos by immunohistochemistry. Embryos at different stages collected from oviducts or uteri were transferred into a flushed oviduct of non-pregnant mice. The oviducts containing embryos were paraffin-embedded and processed for immunostaining. COX-1 immunostaining was at a basal level in zygotes and a low level at the 2-cell stage, reaching a high level from the 4-cell to blastocyst stage. COX-2 immunostaining was at a low level at the zygote stage and was maintained at a high level from the 2-cell to blastocyst stages. A low level of mPGES-1 immunostaining was observed from the zygote to 8-cell stages. The signal for mPGES-1 immunostaining became stronger at the morula stage and was strongly seen at the blastocyst stage. cPGES immunostaining was strongly observed in zygotes, 2-cell and 8-cell embryos. There was a slight decrease in cPGES immunostaining at the 4-cell, morula and blastocyst stages. mPGES-2 immunostaining was at a low level from the zygote to morula stages and at a high level at the blastocyst stage. We found that the COX-1, COX-2, mPGES-1, cPGES and mPGES-2 protein signals were all at a high level at the blastocyst stage. PGE2 produced during the preimplantation development may play roles during embryo transport and implantation.

scholarly journals Are there attacking points in the eicosanoid cascade for chemotherapeutic options in benign meningiomas?

2007 ◽  
Vol 23 (4) ◽  
pp. E8 ◽  
Author(s):  
Christina Pfister ◽  
Rainer Ritz ◽  
Heike Pfrommer ◽  
Antje Bornemann ◽  
Marcos S. Tatagiba ◽  
...  
Keyword(s):  
World Health ◽  
Pcr Analysis ◽  
Prostaglandin E ◽  
Tissue Samples ◽  
Human Cortex ◽  
Normal Human ◽  
Cox 2 ◽  
Cox 1

Object The current treatment for recurrent or malignant meningiomas with adjuvant therapies has not been satisfactory, and there is an intense interest in evaluating new molecular markers to act as therapeutic targets. Enzymes of the arachidonic acid (AA) cascade such as cyclooxygenase (COX)–2 or 5-lipoxygenase (5-LO) are upregulated in a number of epithelial tumors, but to date there are hardly any data about the expression of these markers in meningiomas. To find possible targets for chemotherapeutic intervention, the authors evaluated the expression of AA derivatives at different molecular levels in meningiomas. Methods One hundred and twenty-four meningioma surgical specimens and normal human cortical tissue samples were immunohistochemically and cytochemically stained for COX-2, COX-1, 5-LO, and prostaglandin E receptor 4 (PTGER4). In addition, Western blot and polymerase chain reaction (PCR) analyses were performed to detect the presence of eicosanoids in vivo and in vitro. Results Sixty (63%) of 95 benign meningiomas, 21 (88%) of 24 atypical meningiomas, all five malignant meningiomas, and all normal human cortex samples displayed high COX-2 immunoreactivity. All cultured specimens and IOMM-Lee cells stained positive for COX-2, COX-1, 5-LO, and PTGER4. The PCR analysis demonstrated no changes in eicosanoid expression among meningiomas of different World Health Organization grades and in normal human cortical and dura mater tissue. Conclusions Eicosanoid derivatives COX-1, COX-2, 5-LO, and PTGER4 enzymes show a high universal expression in meningiomas but are not upregulated in normal human cortex and dura tissue. This finding of the ubiquitous presence of these enzymes in meningiomas offers an excellent baseline for testing upcoming chemotherapeutic treatments.

scholarly journals The Induction of Cyclooxygenase-2 in IL-1β-Treated Endothelial Cells is Inhibited by Prostaglandin E2 through cAMP

1999 ◽  
Vol 8 (6) ◽  
pp. 287-294 ◽  
Author(s):  
Pravit Akarasereenont ◽  
Kitirat Techatrisak ◽  
Sirikul Chotewuttakorn ◽  
Athiwat Thaworn
Keyword(s):  
Endothelial Cells ◽  
Biological Activities ◽  
Umbilical Vein ◽  
The Body ◽  
Prostaglandin E ◽  
Dependent Manner ◽  
Negative Feedback Regulation ◽  
Cox 2 ◽  
Arachidonic Acids ◽  
Cox 1

Prostaglandins (PGS) have numerous cardiovascular and inflammatory effects. Cyclooxygenase (COX), which exists as COX-1 and COX-2 isoforms, is the first enzyme in the pathway in which arachidonic acid is converted to PGs. Prostaglandin E2 (PGE2) exerts a variety of biological activities for the maintenance of local homeostasis in the body. Elucidation of PGE2 involvement in the signalling molecules such as COX could lead to potential therapeutic interventions. Here, we have investigated the effects of PGE2 on the induction of COX-2 in human umbilical vein endothelial cells (HUVEC) treated with interleukin-1β (IL-1β 1 ng/ml). COX activity was measured by the production of 6-keto-PGF1α, PGE2, PGF2α and thromboxane B2 (TXB2) in the presence of exogenous arachidonic acids (10 μM for 10 min) using enzyme immunoassay (EIA). COX-1 and COX-2 protein was measured by immunoblotting using specific antibody. Untreated HUVEC contained only COX-1 protein while IL-1β treated HUVEC contained COX-1 and COX-2 protein. PGE2 (3 μM for 24 h) did not affect on COX activity and protein in untreated HUVEC. Interestingly, PGE2 (3 μM for 24 h) can inhibit COX-2 protein, but not COX-1 protein, expressed in HUVEC treated with IL1 β. This inhibition was reversed by coincubation with forskolin (100 μM). The increased COX activity in HUVEC treated with IL-1β was also inhibited by PGE2 (0.03, 0.3 and 3 μM for 24 h) in a dose-dependent manner. Similarly, forskolin (10, 50 or 100 μM) can also reverse the inhibition of PGE2 on increased COX activity in IL-1β treated HUVEC. The results suggested that (i) PGE2 can initiate negative feedback regulation in the induction of COX-2 elicited by IL-1β in endothelial cells, (ii) the inhibition of PGE2 on COX-2 protein and activity in IL-1β treated HUVEC is mediated by cAMP and (iii) the therapeutic use of PGE2 in the condition which COX-2 has been involved may have different roles.

The Cardiovascular Pharmacology of COX-2 Inhibition

Hematology ◽  
2005 ◽  
Vol 2005 (1) ◽  
pp. 445-451 ◽  
Author(s):  
Susanne Fries ◽  
Tilo Grosser
Keyword(s):  
Blood Pressure ◽  
Vascular Function ◽  
Cardiovascular Pharmacology ◽  
Pressure Control ◽  
Baseline Risk ◽  
Controlled Clinical Trials ◽  
Arterial Blood ◽  
Inflammatory Drugs ◽  
Cox 2 ◽  
Cox 1

Abstract Selective inhibitors of cyclooxygenase (COX)-2, the coxibs, were developed to inhibit inflammatory prostaglandins derived from COX-2, while sparing gastroprotective prostaglandins primarily formed by COX-1. However, COX-2-derived prostaglandins mediate not only pain and inflammation but also affect vascular function, the regulation of hemostasis/ thrombosis, and blood pressure control. All coxibs depress COX-2-dependent prostacyclin (PGI2) biosynthesis without effective suppression of platelet COX-1-derived thromboxane (Tx) A2, unlike aspirin or traditional nonsteroidal anti-inflammatory drugs, which inhibit both COX-1 and COX-2. The actions of PGI2 oppose mediators, which stimulate platelets, elevate blood pressure, and accelerate atherogenesis, including TxA2. Indeed, structurally distinct inhibitors of COX-2 have increased the likelihood of hypertension, myocardial infarction and stroke in controlled clinical trials. The detection of these events in patients is related to the duration of exposure and to their baseline risk of cardiovascular disease. Thus, coxibs should be withheld from patients with preexisting cardiovascular risk factors, and exposed patients at low cardiovascular baseline risk should be monitored for changes in their risk factor profile, such as increases in arterial blood pressure.

Role of prostaglandins in collecting duct-derived endothelin-1 regulation of blood pressure and water excretion

2007 ◽  
Vol 293 (6) ◽  
pp. F1805-F1810 ◽  
Author(s):  
Yuqiang Ge ◽  
Kevin A. Strait ◽  
Peter K. Stricklett ◽  
Tianxin Yang ◽  
Donald E. Kohan
Keyword(s):  
Blood Pressure ◽  
Collecting Duct ◽  
Urine Volume ◽  
Mrna Levels ◽  
Water Excretion ◽  
Salt Loading ◽  
Endothelin 1 ◽  
Cox 2 ◽  
Cox 1

Collecting duct (CD)-derived endothelin-1 (ET-1) exerts natriuretic, diuretic, and hypotensive effects. In vitro studies have implicated cyclooxygenase (COX) metabolites, and particularly PGE2, as important mediators of CD ET-1 effects. However, it is unknown whether PGE2 mediates CD-derived ET-1 actions in vivo. To test this, CD ET-1 knockout (KO) and control mice were studied. During normal salt and water intake, urinary PGE2 excretion was unexpectedly increased in CD ET-1 KO mice compared with controls. Salt loading markedly increased urinary PGE2 excretion in both groups of mice; however, the levels remained relatively higher in KO animals. Acutely isolated inner medullary collecting duct (IMCD) from KO mice also had increased PGE2 production. The increased IMCD PGE2 was COX-2 dependent, since NS-398 blocked all PGE2 production. However, increased CD ET-1 KO COX-2 protein or mRNA could not be detected in inner medulla or IMCD, respectively. Inner medullary COX-1 mRNA and protein levels and IMCD COX-1 mRNA levels were unaffected by Na intake or CD ET-1 KO. KO mice on a normal or high-Na diet had elevated blood pressure compared with controls; this difference was not altered by indomethacin or NS-398 treatment. However, indomethacin or NS-398 did increase urine osmolality and reduce urine volume in KO, but not control, animals. In summary, IMCD COX-2-dependent PGE2 production is increased in CD ET-1 KO mice, indicating that CD-derived ET-1 is not a primary regulator of IMCD PGE2. Furthermore, the increased PGE2 in CD ET-1 KO mice partly compensates for loss of ET-1 with respect to maintaining urinary water excretion, but not in blood pressure control.

Intracellular-specific colocalization of prostaglandin E2 synthases and cyclooxygenases in the brain

2004 ◽  
Vol 287 (5) ◽  
pp. R1155-R1163 ◽  
Author(s):  
Alejandro Vazquez-Tello ◽  
Li Fan ◽  
Xin Hou ◽  
Jean-Sébastien Joyal ◽  
Joseph A. Mancini ◽  
...  
Keyword(s):  
Brain Tissue ◽  
Intracellular Localization ◽  
Cysteine Residue ◽  
Prostaglandin E ◽  
Cell Compartment ◽  
Cerebral Microvessels ◽  
Microsomal Membranes ◽  
Cox 2 ◽  
The Brain ◽  
Cox 1

Prostaglandin E2 (PGE2) is the major primary prostaglandin generated by brain cells. However, the coordination and intracellular localization of the cyclooxygenases (COXs) and prostaglandin E synthases (PGESs) that convert arachidonic acid to PGE2 in brain tissue are not known. We aimed to determine whether microsomal and cytosolic PGES (mPGES-1 and cPGES) colocalize and coordinate activity with either COX-1 or COX-2 in brain tissue, particularly during development. Importantly, we found that cytosolic PGES also associates with microsomes (cPGES-m) from the cerebrum and cerebral vasculature of the pig and rat as well as microsomes from various cell lines; this seemed dependent on the carboxyl terminal 35-amino acid domain and a cysteine residue (C58) of cPGES. In microsomal membranes from the postnatal brain and cerebral microvessels of mature animals, cPGES-m colocalized with both COX-1 and COX-2, whereas mPGES-1 was undetectable in these microsomes. Accordingly, in this cell compartment, cPGES could coordinate its activity with COX-2 and COX-1 (partly inhibited by NS398); albeit in microsomes of the brain microvasculature from newborns, mPGES-1 was also present. In contrast, in nuclei of brain parenchymal and endothelial cells, mPGES-1 and cPGES colocalized exclusively with COX-2 (determined by immunoblotting and immunohistochemistry); these PGESs contributed to conversion of PGH2 into PGE2. Hence, contrary to a previously proposed model of exclusive COX-2/mPGES-1 coordination, COX-2 can coordinate with mPGES-1 and/or cPGES in the brain, depending on the cell compartment and the age group.

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