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Journal ArticleDOI

A PPAR-independent pathway to PUFA-induced COX-2 expression

11 Jun 2008-Molecular and Cellular Endocrinology (Elsevier)-Vol. 287, Iss: 1, pp 65-71

TL;DR: The results demonstrate a pathway to the induction of COX-2 by PUFAs requiring NF-kappaB but not PPAR or PKC, and the PPAR-independent effect of PUFA was mimicked by the PKC activators 4beta-PMA and prostaglandin F(2alpha), but was not blocked by thePKC inhibitor RO318425.

AbstractPolyunsaturated fatty acids (PUFAs) induce COX-2 in bovine endometrial stromal cells through activation of peroxisome-proliferator-activated receptor alpha (PPARalpha). We have investigated alternative (PPAR-independent) pathways to COX-2 induction using a reporter construct driven by a COX-2 gene promoter sequence lacking a PPAR response element. This construct was induced by PUFAs, but not by PPAR agonists. PPAR-independent reporter gene expression occurred 6h after PPAR-dependent induction of the endogenous COX-2 gene. In contrast to PPAR-dependent COX-2 induction, which is not affected by NF-kappaB inhibitors, the PPAR-independent pathway was blocked by the NF-kappaB inhibitor MG132 or following deletion of NF-kappaB sites in the COX-2 promoter. The PPAR-independent effect of PUFA was mimicked by the PKC activators 4beta-PMA and prostaglandin F(2alpha), but was not blocked by the PKC inhibitor RO318425. The results demonstrate a pathway to the induction of COX-2 by PUFAs requiring NF-kappaB but not PPAR or PKC.

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A PPAR-independent pathway to PUFA-induced COX-2
expression
K. Derecka, E.L. Sheldrick, D.C. Wathes, D.R.E. Abayasekara, A.P.F. Flint
To cite this version:
K. Derecka, E.L. Sheldrick, D.C. Wathes, D.R.E. Abayasekara, A.P.F. Flint. A PPAR-independent
pathway to PUFA-induced COX-2 expression. Molecular and Cellular Endocrinology, Elsevier, 2008,
287 (1-2), pp.65. �10.1016/j.mce.2008.02.015�. �hal-00532004�

Accepted Manuscript
Title: A PPAR-independent pathway to PUFA-induced COX-2
expression
Authors: K. Derecka, E.L. Sheldrick, D.C. Wathes, D.R.E.
Abayasekara, A.P.F. Flint
PII: S0303-7207(08)00087-7
DOI: doi:10.1016/j.mce.2008.02.015
Reference: MCE 6824
To appear in: Molecular and Cellular Endocrinology
Received date: 5-10-2007
Revised date: 15-2-2008
Accepted date: 16-2-2008
Please cite this article as: Derecka, K., Sheldrick, E.L., Wathes, D.C.,
Abayasekara, D.R.E., Flint, A.P.F., A PPAR-independent pathway to PUFA-
induced COX-2 expression, Molecular and Cellular Endocrinology (2007),
doi:10.1016/j.mce.2008.02.015
This is a PDF file of an unedited manuscript that has been accepted for publication.
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Page 1 of 25
Accepted Manuscript
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Citations
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Journal ArticleDOI
Abstract: OBJECTIVE: To evaluate the role of nuclear factor-κB (NF-κB) in the pathogenesis of endometriosis DESIGN: A literature search was conducted in PubMed to identify all relevant citations RESULT(S): Our findings highlight the important role of NF-κB in the pathophysiology of endometriosis In vitro and in vivo studies show that NF-κB-mediated gene transcription promotes inflammation, invasion, angiogenesis, and cell proliferation and inhibits apoptosis of endometriotic cells Constitutive activation of NF-κB has been demonstrated in endometriotic lesions and peritoneal macrophages of endometriosis patients Agents blocking NF-κB are effective inhibitors of endometriosis development and some drugs with known NF-κB inhibitory properties have proved efficient at reducing endometriosis-associated symptoms in women Iron overload activates NF-κB in macrophages NF-κB activation in macrophages and ectopic endometrial cells stimulates synthesis of proinflammatory cytokines, generating a positive feedback loop in the NF-κB pathway and promoting endometriotic lesion establishment, maintenance and development CONCLUSION(S): NF-κB transcriptional activity modulates key cell processes contributing to the initiation and progression of endometriosis Because endometriosis is a multifactorial disease, inhibiting NF-κB appears to be a promising strategy for future therapies targeting different cell functions involved in endometriosis development, such as cell adhesion, invasion, angiogenesis, inflammation, proliferation, and apoptosis Upcoming research will elucidate these hypotheses

113 citations


Cites background from "A PPAR-independent pathway to PUFA-..."

  • ...MG-132 (47, 69, 70) In vitro, EEC Y IL-6 and LIF In vitro, bovine ESC Y PTGS-2 and COX-2 Parthenolide (69) In vitro, bovine ESC Y PTGS-2 SN-50 (33, 47) In vitro, EEC Y IL-6 and LIF In vivo, nude mouse Y Ec lesion development Y ICAM-1 and [ apoptosis Curcumin (53, 54, 67, 168) In vitro, ESC and EcSC Y MIF In vivo, human Unknown, Y symptoms? Sulindac (55) In vitro, ESC Y RANTES Thalidomide (62) In vitro, EcSC Y IL-8 TPCK (59) In vitro, EcSC Y IL-8 GnRH-a (59) In vivo, human/in vitro, EcSC Y IL-8...

    [...]

  • ...The most accepted hypothesis on the origin of peritoneal endometriosis postulates that this disease originates from regurgitated menstrual endometrial cells (ECs) able to survive, adhere, invade, and proliferate in the peritoneal cavity (5–9)....

    [...]

  • ...In vitro studies in stimulated ECs and EcCs testing different NF-kB inhibitors—including MG132, parthenolide, SN-50, BAY 11-7085, curcumin, sulindac, thalidomide, N-tosyl-l-phenylalanine chloromethyl ketone (TPCK), GnRH agonists, progesterone, progestational compounds, IKK-2 inhibitor, PPAR-g ligand (pioglitazone), IL-10, and NF-kB decoy oligonucleotides (ODNs)—have shown a reduction in proinflammatory, growth, and invasion mediators COX-2, IL-6, leukemia inhibitory factor (LIF), MIF, RANTES, IL-8, MCP-1, GM-CSF, ICAM-1, and MMP-9, have reduced cell proliferation, monocyte chemotactic activity, and cell invasion, and have increased apoptosis as a result of decreased NF-kB activation (33, 47, 53–55, 59, 62–64, 67–70, 87, 88, 159, 160)....

    [...]

  • ...Further studies are needed to understand the complex genomic and nongenomic interactions between estrogen and progesterone, their receptors, NF-kB, and other pathways in ECs and EcCs....

    [...]

  • ...In vitro studies have revealed constitutive and inducible activation of NF-kB in ECs....

    [...]


Journal ArticleDOI
TL;DR: The current understanding of the effects as well as the underlying mechanisms of ω-3 PUFAs on autoimmune diseases is summarized.
Abstract: The recognition of ω-3 polyunsaturated acids (PUFAs) as essential fatty acids to normal growth and health was realized more than 80 years ago. However, the awareness of the long-term nutritional intake of ω-3 PUFAs in lowering the risk of a variety of chronic human diseases has grown exponentially only since the 1980s (1, 2). Despite the overwhelming epidemiological evidence, many attempts of using fish-oil supplementation to intervene human diseases have generated conflicting and often ambiguous outcomes; null or weak supporting conclusions were sometimes derived in the subsequent META analysis. Different dosages, as well as the sources of fish-oil, may have contributed to the conflicting outcomes of intervention carried out at different clinics. However, over the past decade, mounting evidence generated from genetic mouse models and clinical studies has shed new light on the functions and the underlying mechanisms of ω-3 PUFAs and their metabolites in the prevention and treatment of rheumatoid arthritis, systemic lupus erythematosus (SLE), multiple sclerosis, and type 1 diabetes. In this review, we have summarized the current understanding of the effects as well as the underlying mechanisms of ω-3 PUFAs on autoimmune diseases.

44 citations


Journal ArticleDOI
TL;DR: The nature and mechanisms of fatty acid-mediated regulation of CREBh, a recently identified transcription factor that appears to be required for hepatic synthesis of C-reactive protein, are examined, establishing a potential molecular link between fatty acids and inflammation.
Abstract: Excess fatty acids are closely associated with metabolic dysfunction. The deleterious effects of fatty acids relate, in part, to their ability to up-regulate pro-inflammatory cytokines and propagate a state of systemic inflammation. CREBh is a recently identified transcription factor that appears to be required for hepatic synthesis of C-reactive protein. Recent data suggest that fatty acids can up-regulate CREBh, thus establishing a potential molecular link between fatty acids and inflammation. The aim of this study was to examine the nature and mechanisms of fatty acid-mediated regulation of CREBh. H4IIE liver cells were incubated in the absence or presence of varying concentrations (50-500 μM) of albumin-bound, long-chain saturated (palmitate, stearate) or unsaturated (oleate, linoleate) fatty acids (1-16 h). All fatty acids significantly increased CREBh gene expression via transcriptional mechanisms, at concentrations as low as 50 μM. Palmitate- or oleate-mediated up-regulation of CREBh was not inhibited by triacsin C, an inhibitor of long-chain fatty acyl CoA synthetase, or by the PPARα antagonist, MK886. Inhibition of proteasome activity with MG132 or lactacystin, or inclusion of insulin reduced palmitate- and oleate-mediated increases in CREBh mRNA. Finally, we examined fatty acid regulation of CREBh in vivo. Male Wistar rats were exposed to a 4-h pancreatic clamp combined with infusion of saline or a mixed lipid emulsion. CREBh mRNA and protein were significantly increased in rats exposed to the lipid infusion compared to the saline group. Collectively, these results may have important implications for metabolic diseases characterized by excess fatty acids, insulin resistance, and inflammation.

37 citations


Cites background from "A PPAR-independent pathway to PUFA-..."

  • ...Recent data suggest that the proteasome inhibitor MG132 prevents fatty acid induction of the pro-inflammatory enzyme cyclooxygenase-2 in endometrial stromal cells [23]....

    [...]


Journal ArticleDOI
TL;DR: This study demonstrated the cross talk between downstream signaling of CLA and important hormone regulators of endocrine system, i.e. FSH and IGF1, on buffalo granulosa cell function (proliferation and steroidogenesis) and found that CLA intervenes the IGF1 signaling by decreasing p-Akt.
Abstract: Conjugated linoleic acid (CLA) has drawn much interest in last two decades in the area ranging from anticancer activity to obesity. A number of research papers have been published recently with regard to CLA's additional biological functions as reproductive benefits. However, not much is known how this mixture of isomeric compounds mediates its beneficial effects particularly on fertility. In this study, we demonstrated the cross talk between downstream signaling of CLA and important hormone regulators of endocrine system, i.e. FSH and IGF1, on buffalo granulosa cell function (proliferation and steroidogenesis). Experiments were performed in primary serum-free buffalo granulosa cell culture, where cells were incubated with CLA in combination with FSH (25 ng/ml) and IGF1 (50 ng/ml). Results showed that 10 μM CLA inhibits FSH- and IGF1-induced granulosa cell proliferation; aromatase, GATA4, and IGF1 mRNA; and estradiol-17β production. Western blot analysis of total cell lysates revealed that CLA intervenes the IGF1 signaling by decreasing p-Akt. In addition, CLA was found to upregulate peroxisome proliferator-activated receptor-gamma (PPARG) and phosphatase and tensin homolog (PTEN) level in granulosa cells. Further study using PPARG- and PTEN-specific inhibitors supports the potential role of CLA in granulosa cell proliferation and steroidogenesis involving PPARG, PTEN, and PI3K/Akt pathway.

29 citations


Cites background from "A PPAR-independent pathway to PUFA-..."

  • ...However, PPARG-independent effects also cannot be denied completely as PUFAs are known to take PPAR-independent pathways (Derecka et al. 2008) and also PPARG inhibitor (GW9662) inhibited the cell growth of human tumor mammary cell line, which supports the existence of PPARG-independent pathways…...

    [...]


Journal ArticleDOI
25 May 2012-PLOS ONE
TL;DR: Angiotensin II induced Cox-2 gene expression by activating the calcineurin/NFAT signaling pathway in endometrial stromal cells of non-pregnant but not of early-p Regnant rats, which might be related to differential roles that COX-2 plays in the endometrium.
Abstract: Cyclooxygenase (COX)-2, the inducible isoform of cyclooxygenase, plays a role in the process of uterine decidualization and blastocyst attachment. On the other hand, overexpression of COX-2 is involved in the proliferation of the endometrial tissue during endometriosis. Deregulation of the renin-angiotensin-system plays a role in the pathophysiology of endometriosis and pre-eclampsia. Angiotensin II increases intracellular Ca2+ concentration by targeting phospholypase C-gamma in endometrial stromal cells (ESC). A key element of the cellular response to Ca2+ signals is the activity of the Ca2+- and calmodulin-dependent phosphatase calcineurin. Our first aim was to study whether angiotensin II stimulated Cox-2 gene expression in rat ESC and to analyze whether calcineurin activity was involved. In cells isolated from non-pregnant uteri, COX-2 expression -both mRNA and protein- was induced by co-stimulation with phorbol ester and calcium ionophore (PIo), as well as by angiotensin II. Pretreatment with the calcineurin inhibitor cyclosporin A inhibited this induction. We further analyzed the role of the calcineurin/NFAT signaling pathway in the induction of Cox-2 gene expression in non-pregnant rat ESC. Cyclosporin A abolished NFATc1 dephosphorylation and translocation to the nucleus. Cyclosporin A also inhibited the transcriptional activity driven by the Cox-2 promoter. Exogenous expression of the peptide VIVIT -specific inhibitor of calcineurin/NFAT binding- blocked the activation of Cox-2 promoter and the up-regulation of COX-2 protein in these cells. Finally we analyzed Cox-2 gene expression in ESC of early-pregnant rats. COX-2 expression -both mRNA and protein- was induced by stimulation with PIo as well as by angiotensin II. This induction appears to be calcineurin independent, since it was not abrogated by cyclosporin A. In conclusion, angiotensin II induced Cox-2 gene expression by activating the calcineurin/NFAT signaling pathway in endometrial stromal cells of non-pregnant but not of early-pregnant rats. These results might be related to differential roles that COX-2 plays in the endometrium.

19 citations


Cites background from "A PPAR-independent pathway to PUFA-..."

  • ...It has been found previously that PKC activators, such as PMA, induced COX-2 expression in ESC [57]....

    [...]


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Journal ArticleDOI
TL;DR: This assay is very reproducible and rapid with the dye binding process virtually complete in approximately 2 min with good color stability for 1 hr with little or no interference from cations such as sodium or potassium nor from carbohydrates such as sucrose.
Abstract: A protein determination method which involves the binding of Coomassie Brilliant Blue G-250 to protein is described. The binding of the dye to protein causes a shift in the absorption maximum of the dye from 465 to 595 nm, and it is the increase in absorption at 595 nm which is monitored. This assay is very reproducible and rapid with the dye binding process virtually complete in approximately 2 min with good color stability for 1 hr. There is little or no interference from cations such as sodium or potassium nor from carbohydrates such as sucrose. A small amount of color is developed in the presence of strongly alkaline buffering agents, but the assay may be run accurately by the use of proper buffer controls. The only components found to give excessive interfering color in the assay are relatively large amounts of detergents such as sodium dodecyl sulfate, Triton X-100, and commercial glassware detergents. Interference by small amounts of detergent may be eliminated by the use of proper controls.

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01 Apr 1984-Nature
TL;DR: Protein kinase C probably serves as a receptor for the tumour promoters and further exploration of the roles of this enzyme may provide clues for understanding the mechanism of cell growth and differentiation.
Abstract: Protein kinase C has a crucial role in signal transduction for a variety of biologically active substances which activate cellular functions and proliferation. When cells are stimulated, protein kinase C is transiently activated by diacylglycerol which is produced in the membrane during the signal-induced turnover of inositol phospholipids. Tumour-promoting phorbol esters, when intercalated into the cell membrane, may substitute for diacylglycerol and permanently activate protein kinase C. The enzyme probably serves as a receptor for the tumour promoters. Further exploration of the roles of this enzyme may provide clues for understanding the mechanism of cell growth and differentiation.

6,886 citations


Journal ArticleDOI
18 Jul 1970-Nature
TL;DR: Evidence of an active linkage between the human genes that control lactate dehydrogenase B and peptidase B is presented, but it is concluded that there is no link between the genes for lactate dehydration A and lactatehydrogenase A.
Abstract: Evidence of an active linkage between the human genes that control lactate dehydrogenase B and peptidase B is presented. It is also concluded that there is no link between the genes for lactate dehydrogenase A and lactate dehydrogenase B.

1,143 citations


Journal ArticleDOI
TL;DR: A novel mechanism by which fatty acids modulate signaling pathways and target gene expression is represented by both SFA-induced COX-2 expression and its inhibition by UFAs are mediated through a common signaling pathway derived from Tlr4.
Abstract: Results from our previous studies demonstrated that activation of Toll-like receptor 4 (Tlr4), the lipopolysaccharide (LPS) receptor, is sufficient to induce nuclear factor kappaB activation and expression of inducible cyclooxygenase (COX-2) in macrophages. Saturated fatty acids (SFAs) acylated in lipid A moiety of LPS are essential for biological activities of LPS. Thus, we determined whether these fatty acids modulate LPS-induced signaling pathways and COX-2 expression in monocyte/macrophage cells (RAW 264.7). Results show that SFAs, but not unsaturated fatty acids (UFAs), induce nuclear factor kappaB activation and expression of COX-2 and other inflammatory markers. This induction is inhibited by a dominant-negative Tlr4. UFAs inhibit COX-2 expression induced by SFAs, constitutively active Tlr4, or LPS. However, UFAs fail to inhibit COX-2 expression induced by activation of signaling components downstream of Tlr4. Together, these results suggest that both SFA-induced COX-2 expression and its inhibition by UFAs are mediated through a common signaling pathway derived from Tlr4. These results represent a novel mechanism by which fatty acids modulate signaling pathways and target gene expression. Furthermore, these results suggest a possibility that propensity of monocyte/macrophage activation is modulated through Tlr4 by different types of free fatty acids, which in turn can be altered by kinds of dietary fat consumed.

1,087 citations


Journal ArticleDOI
TL;DR: It is demonstrated that only MEp and not MEd is able to bind PPAR/retinoid X receptor (RXR) heterodimers and mediate peroxisome proliferator signaling.
Abstract: The malic enzyme (ME) gene is a target for both thyroid hormone receptors and peroxisome proliferator-activated receptors (PPAR). Within the ME promoter, two direct repeat (DR)-1-like elements, MEp and MEd, have been identified as putative PPAR response elements (PPRE). We demonstrate that only MEp and not MEd is able to bind PPAR/retinoid X receptor (RXR) heterodimers and mediate peroxisome proliferator signaling. Taking advantage of the close sequence resemblance of MEp and MEd, we have identified crucial determinants of a PPRE. Using reciprocal mutation analyses of these two elements, we show the preference for adenine as the spacing nucleotide between the two half-sites of the PPRE and demonstrate the importance of the two first bases flanking the core DR1 in 5'. This latter feature of the PPRE lead us to consider the polarity of the PPAR/RXR heterodimer bound to its cognate element. We demonstrate that, in contrast to the polarity of RXR/TR and RXR/RAR bound to DR4 and DR5 elements respectively, PPAR binds to the 5' extended half-site of the response element, while RXR occupies the 3' half-site. Consistent with this polarity is our finding that formation and binding of the PPAR/RXR heterodimer requires an intact hinge T region in RXR while its integrity is not required for binding of the RXR/TR heterodimer to a DR4.

350 citations


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