Echinodorus macrophyllus: Hydroxycinnamoyl derivatives reduces neutrophil migration through modulation of cytokines, chemokines, and prostaglandin in the air-pouch model

ETHNOPHARMACOLOGICAL RELEVANCE

In Brazil, Echinodorus macrophyllus (Alismataceae), popularly known as chapéu-de-couro, is used to treat inflammatory diseases. Previous studies have shown a significant decrease in the acute inflammation for the aqueous extract of E. macrophyllus (AEEm) and its ethanolic fraction (Fr20).

AIM OF THE STUDY

This work fractionated Fr20, identified the fraction and substances responsible for the in vivo anti-inflammatory property, and demonstrated important immunomodulatory mechanisms of action.

MATERIALS AND METHODS

Fr20 was fractionated using Sephadex LH-20, and the most active fraction was chromatographically analyzed (HPLC-DAD and UPLC-ESI-TOF-MS). Leukotriene B4, Prostaglandin E2, and cytokines were determined by the enzyme-linked immunosorbent assay and in vivo acute inflammation by the air pouch model.

RESULTS

The subfractions SF1, SF3, and mainly the SF4 decreased NO levels (p < 0.05). SF3 and SF4 showed high DPPH scavenger activity. SF1 was more effective than SF4 in reducing vasodilation, redness, and leukocyte migration into the 4-h air pouch. SF1 inhibited 90.5% (100 mg/kg) and SF4 54.0% (50 mg/kg), mainly affecting the number of neutrophils. SF1 and SF4 reduced the protein level in the exudate. SF1 was also more effective in inhibiting neutrophil migration in a transwell assay (46.3%) and reduced (86.1%) the Leukotriene B4 level in the exudate. After five days of treatment, some SF1 anti-inflammatory mechanisms were evaluated in the air pouch's 24 h exudate and tissue. Despite the high level of inflammation of the control group in this condition, SF1 confirmed the decrease in the protein level and neutrophils migration into the pouch. It decreased the number of bone marrow cells, indicating a systemic effect of SF1. SF1 also decreased TNF-α (87%), IL-1β (77%), CKCL1/KC (71.3%), and PGE2 (97.8%) and increased IL-10 (74.1%) levels in the air pouch exudate. Phytochemical analysis of SF1 indicates mainly hydroxycinnamoyl derivatives.

CONCLUSION

Hydroxycinnamoyl derivatives present in SF1 are related to the crucial anti-inflammatory mechanisms of E. macrophyllus, decreasing the levels of TNF-α, IL-1β, CKCL1/KC, LTB4, and PGE2 on the exudate. These results explain the reduction of vasodilatation, erythema, and neutrophil migration into the air pouch model, confirming this plant's anti-inflammatory potential.

Gastroprotective action of the ethanol extract of Leonurus sibiricus L. (Lamiaceae) in mice

ETHNOPHARMACOLOGICAL RELEVANCE

Leonurus sibiricus L. (Lamiaceae) is a medicinal plant known in Brazil as "rubim" or "erva de macaé". It is used for various purposes, including stomach disorders.

AIM OF THE STUDY

To evaluate the effect of the ethanol extract of the aerial parts of L. sibiricus (EELs) in models of gastric damage in mice.

MATERIAL AND METHODS

The effect of EELs (50, 100 and 300 mg/kg, p.o., 1 h before induction) was tested on acidified ethanol (ACEt)-induced gastric ulcers. Additionally, we tested the effect of EELs (by intraduodenal administration) in the pylorus ligation (PL) model.

RESULTS

Pretreatment with EELs, at 300 mg/kg, but not 50 and 100 mg/kg, reduced the relative area of gastric ulcers induced by ACEt (p < 0.01) and lipoperoxidation (p < 0.001), and increased the sulfhydryl content (p < 0.01) in the stomach in comparison with the vehicle group. Pretreatment with N-ethylmaleimide (a blocker of non-protein sulfhydryl groups, 10 mg/kg, i.p.) or glibenclamide (a K_ATP channel blocker, 10 mg/kg, i.p.) inhibited the gastroprotective response caused by EELs (300 mg/kg; p < 0.001), but there were no alterations due to pretreatments with inhibitors of the synthesis of prostaglandins (indomethacin, 10 mg/kg), nitric oxide (L-NAME, 70 mg/kg) or hydrogen sulfide (DL-propargylglycine, 10 mg/kg). Treatment with EELs (300 mg/kg) reduced mucus production (p < 0.001) and the volume of gastric secretion (p < 0.001) after PL without affecting gastric acidity or pH.

CONCLUSIONS

These results provide evidence that EELs exerts gastroprotective action in mice, with the participation of oxidative stress and mediation of NP-SH, K_ATP channels and mucus production.

Genome-Wide Analysis Indicates a Complete Prostaglandin Pathway from Synthesis to Inactivation in Pacific White Shrimp, Litopenaeus vannamei

Prostaglandins (PGs) play many essential roles in the development, immunity, metabolism, and reproduction of animals. In vertebrates, arachidonic acid (ARA) is generally converted to prostaglandin G₂ (PGG₂) and H₂ (PGH₂) by cyclooxygenase (COX); then, various biologically active PGs are produced through different downstream prostaglandin synthases (PGSs), while PGs are inactivated by 15-hydroxyprostaglandin dehydrogenase (PGDH). However, there is very limited knowledge of the PG biochemical pathways in invertebrates, particularly for crustaceans. In this study, nine genes involved in the prostaglandin pathway, including a COX, seven PGSs (PGES, PGES2, PGDS1/2, PGFS, AKR1C3, and TXA2S), and a PGDH were identified based on the Pacific white shrimp (Litopenaeus vannamei) genome, indicating a more complete PG pathway from synthesis to inactivation in crustaceans than in insects and mollusks. The homologous genes are conserved in amino acid sequences and structural domains, similar to those of related species. The expression patterns of these genes were further analyzed in a variety of tissues and developmental processes by RNA sequencing and quantitative real-time PCR. The mRNA expression of PGES was relatively stable in various tissues, while other genes were specifically expressed in distant tissues. During embryo development to post-larvae, COX, PGDS1, GDS2, and AKR1C3 expressions increased significantly, and increasing trends were also observed on PGES, PGDS2, and AKR1C3 at the post-molting stage. During the ovarian maturation, decreasing trends were found on PGES1, PGDS2, and PGDH in the hepatopancreas, but all gene expressions remained relatively stable in ovaries. In conclusion, this study provides basic knowledge for the synthesis and inactivation pathway of PG in crustaceans, which may contribute to the understanding of their regulatory mechanism in ontogenetic development and reproduction.

Prostaglandins regulate humoral immune responses in Aedes aegypti

Prostaglandins (PGs) are immuno-active lipids that mediate the immune response in invertebrates and vertebrates. In insects, PGs play a role on different physiological processes such as reproduction, ion transport and regulation of cellular immunity. However, it is unclear whether PGs play a role in invertebrate's humoral immunity, and, if so, which immune signaling pathways would be modulated by PGs. Here, we show that Aedes aegypti gut microbiota and Gram-negative bacteria challenge induces prostaglandin production sensitive to an irreversible inhibitor of the vertebrate cyclooxygenase, acetylsalicylic acid (ASA). ASA treatment reduced PG synthesis and is associated with decreased expression of components of the Toll and IMD immune pathways, thereby rendering mosquitoes more susceptible to both bacterial and viral infections. We also shown that a cytosolic phospholipase (PLAc), one of the upstream regulators of PG synthesis, is induced by the microbiota in the midgut after blood feeding. The knockdown of the PLAc decreased prostaglandin production and enhanced the replication of Dengue in the midgut. We conclude that in Ae. aegypti, PGs control the amplitude of the immune response to guarantee an efficient pathogen clearance.

The Effect of Omega-3 and Omega-6 Polyunsaturated Fatty Acids on the Production of Cyclooxygenase and Lipoxygenase Metabolites by Human Umbilical Vein Endothelial Cells

Although the correlation between polyunsaturated fatty acids (PUFA) and the production of pro- and anti-inflammatory metabolites is well documented, little is known about the simultaneous effect of different PUFA on the production of cyclooxygenase and lipoxygenase metabolites. The present research examines the association between different omega-3 (ω-3) and omega-6 (ω-6) PUFA and the release of four cyclooxygenase and six lipoxygenase metabolites in cell medium by human umbilical vein endothelial cells (HUVEC). The different combinations of ω-3 and ω-6 PUFA were prepared according to a full 24 factorial design that enables studying not only the main effects but also the different interactions between fatty acids. In addition, interactions diagrams and principal component analysis were useful tools for interpreting higher order interactions. To the best of our knowledge, this is the first report addressing the combined effect of ω-3 and ω-6 PUFA on the signaling of prostaglandins, prostacyclins, leukotrienes and resolvins by HUVEC.

Modulation of the biomarkers of inflammation and oxidative stress by ruminant trans fatty acids and dairy proteins in vascular endothelial cells (HUVEC)

This study aimed to determine whether dairy macronutrients alter markers of inflammation and oxidative stress in endothelial cells. Human endothelial cells (HUVEC) were treated with ruminant trans fatty acids (rTFA), either trans-vaccenic acid (tVA) or trans-palmitoleic acid (tPA), whey protein hydrolysate, leucine or combinations of rTFA and dairy protein compounds. Industrial TFA elaidic acid (EA) was also investigated and compared with rTFA. Inflammatory prostaglandins (PG) and F₂-isoprostanes (F₂-isoP) isomers, markers of oxidative stress, were assessed in cell supernatants by LC-MS/MS. Both tVA and tPA, as well as whey protein hydrolysate, decreased TNFα-induced PG excretion. Combinations of rTFA and dairy protein compounds decreased inflammation to a similar extent than rTFA alone. EA increased class VI F₂-isoP isomers, whereas tVA mostly raised class III isomers. In summary, rTFA decreased inflammatory markers and increased oxidative stress markers in endothelial cells. Combinations of rTFA with whey proteins or leucine showed no additive effect.

Lipid Droplet Formation, Their Localization and Dynamics during Leishmania major Macrophage Infection

Leishmania, the causative agent of vector-borne diseases, known as leishmaniases, is an obligate intracellular parasite within mammalian hosts. The outcome of infection depends largely on the activation status of macrophages, the first line of mammalian defense and the major target cells for parasite replication. Understanding the strategies developed by the parasite to circumvent macrophage defense mechanisms and to survive within those cells help defining novel therapeutic approaches for leishmaniasis. We previously showed the formation of lipid droplets (LDs) in L. major infected macrophages. Here, we provide novel insights on the origin of the formed LDs by determining their cellular distribution and to what extent these high-energy sources are directed to the proximity of Leishmania parasites. We show that the ability of L. major to trigger macrophage LD accumulation is independent of parasite viability and uptake and can also be observed in non-infected cells through paracrine stimuli suggesting that LD formation is from cellular origin. The accumulation of LDs is demonstrated using confocal microscopy and live-cell imagin in parasite-free cytoplasmic region of the host cell, but also promptly recruited to the proximity of Leishmania parasites. Indeed LDs are observed inside parasitophorous vacuole and in parasite cytoplasm suggesting that Leishmania parasites besides producing their own LDs, may take advantage of these high energy sources. Otherwise, these LDs may help cells defending against parasitic infection. These metabolic changes, rising as common features during the last years, occur in host cells infected by a large number of pathogens and seem to play an important role in pathogenesis. Understanding how Leishmania parasites and different pathogens exploit this LD accumulation will help us define the common mechanism used by these different pathogens to manipulate and/or take advantage of this high-energy source.

Gastroprotective effect of diligustilide isolated from roots of Ligusticum porteri coulter & rose (Apiaceae) on ethanol-induced lesions in rats

ETHNOPHARMACOLOGICAL RELEVANCE

The rhizome of Ligusticum porteri Coulter& Rose (LP) has been traditionally used by the ethnic group Raramuri in the North of México for treatment of diabetes, tuberculosis, stomachaches, diarrhea and ritual healing ceremonies. It is use as antiulcer remedy has been extended to all Mexico.

AIM OF THE STUDY

To evaluate the gastroprotective activity of LP organic extracts and the major natural product diligustilide (DLG),using as experimental model the inhibition of the ethanol-induced lesions in rats.

MATERIALS AND METHODS

Gastric ulcers were induced by intragastric instillation of absolute ethanol (1 mL). We tested the gastroprotective activity of the organic extracts of LP and the pure compound DLG. The ulcer index (UI) was determined to measure the activity. In order to elucidate the action mechanism of DLG the animals were treated with L-NAME, N-ethylmalemide, Forskolin, 2',5'-dideoxyadenosine, Indomethacin, Glibenclameide, Diazoxide, NaHS and DL-Propargylglycine. The pylorus-ligated rat model was used to measure gastric secretion.

RESULTS

The oral administration of organic extracts of Ligusticum porteri showed gastroprotective effect at 30 mg/Kg on ethanol induced gastric lesions; hexane and dichloromethane extracts were the most active. DLG was the major compound in the hexane extract. This compound at 10 mg/kg prevented significantly the gastric injuries induced by ethanol. The alkylation of endogenous non-protein-SH groups with N-ethylmaleimide abolished the gastroprotective effect of DLG and blocking the formation of endogenous prostaglandins by the pretreatment with indomethacin attenuated the gastroprotective effect of DLG.

CONCLUSION

The gastroprotective activity demonstrated in this study tends to support the ethnomedical use of Ligusticum porteri roots. DLG, isolated as major compound of this medicinal plant has a clear gastroprotective effect on the ethanol-induced gastric lesions. The results suggest that the antiulcer activity of DLG depends on the participation of the endogenous non-protein -SH groups and prostaglandins.

Production of prostaglandins in placentae and corpus luteum in pregnant hinds of red deer (Cervus elaphus)

Prostaglandins (PGs) are synthesized from arachidonic acid by prostaglandin synthase 2 (PTGS2) and specific terminal PG synthases such as PGES and PGFS. The role of PGs in the reproductive processes of domestic ruminants is well recognized, whereas in cervidae, it is almost unknown, although it is noteworthy because some species of this family are valued in meat production and trophies. The aim of this study was to determine an effective marker of pregnancy and investigate the production and secretion of PGs in placenta and CL tissue in pregnancy. In the preliminary experiment, the levels of progesterone and 17-β estradiol (RIA; N = 14 divided into seven pregnant and seven nonpregnant hinds) were measured in the peripheral blood. In the main experiment, a comparison of messenger RNA (real-time polymerase chain reaction) and protein expression (Western blotting) of PTGS2, PGES, and PGFS, the level of prostaglandin E2 (PGE2) and PGF2α in the placentae and CL in pregnant hinds (aged 3-4 years, ca. 100 days of pregnancy, N = 6). In pregnant hinds, the level of progesterone in the blood was higher than that in nonpregnant hinds (P < 0.05), whereas the level of E2 was similar in all animals (P > 0.05). The highest messenger RNA expression of PTGS2, PGES, and PGFS was observed in the placentae than in the CL (P < 0.05). The protein expression of PTGS2 and PGES was elevated in the placentae compared with the CL (P < 0.05). The PGE2 output was the highest in cotyledonary tissue (P < 0.05). Pregnancy development in hinds around 100 days is regulated by arachidonic acid metabolites, especially PGE2 produced by the placentae, which production increases in pregnancy. Further studies are required to unravel the mechanisms involved in the regulation of PG and biosynthetic enzymes in uteroplacental and ovarian tissues during pregnancy in red deer females.

NAD(P)H quinone oxidoreductase 1 (NQO1)-bioactivated pronqodine A regulates prostaglandin release from human synovial sarcoma cells

Natural products have contributed to the elucidation of biological mechanisms as well as drug discovery research. Even now, the expectation for natural products is undiminished. We screened prostaglandin release inhibitors that had no effect on in vitro cyclooxygenase activity derived from natural product sources and discovered pronqodine A. Using spectral analysis and total synthesis, the structure of pronqodine A was shown to be a benzo[d]isothiazole-4,7-dione analogue. Evaluation of the biological activity of pronqodine A revealed that the NAD(P)H dehydrogenase quinone 1 (NQO1) converted pronqodine A into a two-electron reductive form. The reductive form underwent autoxidation and reversed to its native form immediately with the generation of reactive oxygen species. Further investigations proved that pronqodine A inhibited cyclooxygenase enzyme activity only in the presence of NQO1. Pronqodine A acts as a potential bioreductive compound, inhibiting prostaglandin release in selectively activated NQO1-expressing cells.

Effects of oxytocin, lipopolysaccharide (LPS), and polyunsaturated fatty acids on prostaglandin secretion and gene expression in equine endometrial explant cultures

Increased secretion of prostaglandin F(2)α (PGF(2)α) within the uterus because of uterine inflammation can cause luteolysis and result in early embryonic loss. Supplementation with polyunsaturated fatty acids (PUFAs) has been shown to influence PG production in many species, although the effects on the mare remain unknown. The present study aimed to determine fatty acid uptake in equine endometrial explants and evaluate their influence on PG secretion and expression of enzymes involved in PG synthesis in vitro. Equine endometrial explants were treated with 100 μM arachidonic acid, eicosapentaenoic acid, or docosahexaenoic acid and then challenged with oxytocin (250 nM) or lipopolysaccharide (LPS; 1 μg/mL). Production of PGF(2)α and PG E(2) (PGE(2)) was measured, and mRNA expression of enzymes involved in PG synthesis was determined with quantitative real-time PCR. Media concentrations of PGF(2)α and PGE(2) were higher (P < 0.0001) from endometrial explants challenged with oxytocin or LPS compared with controls despite which fatty acid was added. Only DHA lowered (P < 0.0001) media concentrations of PGF(2)α and PGE(2) from explants. Endometrial explants stimulated with oxytocin had increased expression of PG-endoperoxide synthase 1 (PTGS1; P < 0.02), PG-endoperoxide synthase 2 (PTGS2; P < 0.001), PG F(2)α synthase (PGFS; P < 0.01), PG E(2) synthase (PGES; P < 0.01), and phospholipase A(2) (PLA(2); P < 0.005) compared with controls and regardless of fatty acid treatment; whereas stimulation with LPS increased expression of PTGS2 (P < 0.004), PGFS (P < 0.03), PGES (P < 0.01), and PLA(2) (P < 0.01) compared with controls and regardless of fatty acid treatment. Treatment with PUFAs, specifically DHA, can influence PG secretion in vitro through mechanisms other than enzyme expression.

Genetic variation in inflammatory pathways is related to colorectal cancer survival

PURPOSE

Prognosis of patients with colorectal cancer (CRC) is associated with systemic inflammation, and anti-inflammatory drugs can reduce both CRC incidence and mortality. Genetic variation in proinflammatory pathways can affect an individual's CRC risk. However, few studies have investigated the prognostic importance of this genetic variation in CRC patients.

EXPERIMENTAL DESIGN

We investigated the association between CRC survival and genetic variation in proinflammatory pathways among patients from the Puget Sound Surveillance Epidemiology and End Results registry. Single-nucleotide polymorphisms were genotyped in five genes (PTGS-1, PTGS-2, MRP4, NFκB, and IκBKβ). Vital status was ascertained through linkage to the National Death Index. Cox proportional hazards regression was used to calculate HRs and 95% confidence intervals (CI). The false discovery rate method of Benjamini and Hochberg was applied to address multiple testing.

RESULTS

Four PTGS-1 variants were associated with CRC survival. One, G>A intron 9 (rs1213266), was associated with approximately 50% lower CRC mortality (HR(AA/AG vs. GG) = 0.48; 95% CI, 0.25-0.93). Three variants, including L237M, resulted in significantly elevated CRC mortality risk, with HRs ranging from approximately 1.5 to 2.0. Two variants in IκBKβ, including R526Q, were significantly associated with CRC survival. Correction for multiple testing indicated that variants in both PTGS-1 and IκBKβ are reproducibly associated with CRC survival.

CONCLUSION

Our findings suggest that genetic variation in proinflammatory pathways may be important for CRC prognosis. This investigation represents one of the first descriptions of the relationship between inherited polymorphisms and mortality in CRC patients and provides a starting point for further research.

Regulation of Nur77 gene expression by prostanoids in cementoblastic cells

OBJECTIVE

The inflammatory cytokine interleukin-1 (IL-1) decreases mineralisation by immortalized mouse-derived cementoblastic cells (OC-CM cells), whilst various prostanoids, including fluprostenol (flup) increase it. Subtraction hybridisation conducted on flup minus IL-1-treated OC-CM cells revealed that one of the primary response genes preferentially induced by flup is the transcription factor Nur77. The objective of this study was to examine the signal transduction cascades regulating prostanoid induction of Nur77 gene expression in OC-CM cells.

METHODS

Confluent OC-CM cells were treated with prostaglandin E(2) (PGE(2)), prostaglandin F(2alpha) (PGF(2alpha)), specific activators of the various EP prostanoid receptors and of the FP prostanoid receptor, and direct activators/inhibitors of the cyclic AMP-protein kinase A (PKA), protein kinase C (PKC) and intracellular calcium pathways. Nur77 gene expression was examined by mRNA extraction and Northern blot analysis.

RESULTS

PGE(2) and PGF(2alpha) treatment of OC-CM cells significantly increased Nur77 mRNA expression in a time- and dose-dependent fashion. Both the EP1 prostanoid receptor-specific activator 16,16-dimethyl-PGE(2) and the FP prostanoid receptor-specific activator flup significantly increased Nur77 gene expression by OC-CM cells as compared to vehicle-treated controls. Increase in Nur77 gene expression was also observed when direct activators of the PKA, PKC and intracellular calcium pathways were used to treat OC-CM cells. Direct inhibition of the PKA, PKC and intracellular calcium pathways abrogated Nur77 gene expression induced by OC-CM cell treatment with PGE(2) and PGF(2alpha).

CONCLUSION

Nur77 is a primary gene expressed by OC-CM cells and its induction appears to be mediated by the PKA, PKC and intracellular calcium pathways. Nur77 may affect expression of downstream target genes in OC-CM cells and partially regulate cementoblast cell function.

The role of p38 mitogen-activated kinase (MAPK) in the mechanism regulating cyclooxygenase gene expression in equine leukocytes

The goal of this study was to define the role for p38 mitogen-activated kinase (MAPK) in the signaling mechanism regulating pro-inflammatory cyclooxygenase (COX) gene expression in lipopolysaccharide (LPS)-activated equine leukocytes for the purposes of identifying novel targets for anti-inflammatory therapy in endotoxemic horses. The p38 MAPK has been shown to positively regulate inflammatory gene expression in human leukocytes and can be activated by a variety of stimuli including LPS, TNF-alpha, and IL-1. Activation-associated phosphorylated p38 MAPK has been implicated in the up-regulation of several inflammatory genes, including COX-2 which ultimately results in the production of prostanoids that are responsible for the pathophysiology associated with endotoxemia. Our hypothesis is that activation of p38 MAPK is essential for LPS-induced COX-2 expression in equine peripheral blood leukocytes. We tested our hypothesis by investigating the effects of the specific p38 MAPK inhibitors SB203580 and SB202190 on LPS-induced COX-2 protein expression and PGE(2) production in equine leukocytes. LPS stimulation activated p38 MAPK and increased COX-2 expression in a dose-dependent manner with maximal activation observed after 30min and 4h, respectively, at a concentration of 10 ng/ml LPS. In contrast, LPS stimulation did not affect COX-1 protein expression. Pretreatment with SB203580 or SB202190 significantly inhibited LPS-induced activation-associated p38 MAPK phosphorylation, COX-2 mRNA and protein levels, and PGE(2) production in equine leukocytes. Maximal inhibition of LPS-induced COX-2 protein expression was achieved at a concentration of 10 microM SB203580. We concluded that p38 MAPK is essential for LPS-induced COX-2 expression suggesting that p38 MAPK is a potential target for anti-inflammatory therapy during equine endotoxemia.

Mifepristone induced progesterone withdrawal reveals novel regulatory pathways in human endometrium

In women, a single dose of the antiprogestin mifepristone (RU486) in the secretory phase rapidly renders the endometrium unreceptive and is followed by endometrial breakdown and menstruation within 72 h. This model provides a system to identify progesterone-regulated genes, which may be involved in endometrial receptivity and the induction of menstruation. We used cDNA microarrays to monitor the response of the endometriuim over 24 h following administration of mifepristone in the mid-secretory phase. We identified 571 transcripts whose expression was significantly altered, representing 131 biochemical pathways. These include new progesterone regulated members of the Wnt, matrix metalloproteinase (MMP), prostaglandin (PG) and chemokine regulatory pathways. Transcripts involved in thyroid hormone metabolism and signalling such as type II iodothyronine deiodinase and thyroid receptors were also found to be highly regulated by progesterone antagonism in the endometrium. Transcripts required for thyroid hormone synthesis such as thyroid peroxidase (TPO) and thyroglobulin (TG) were also expressed, indicating that the endometrium may be a site of thyroxin production. These results add to the existing knowledge of the role of the Wnt, chemokine, MMP and PG pathways in receptivity and early menstrual events. They provide in vivo evidence supporting direct or indirect regulation of many new transcripts by progesterone. We have also identified for the first time the very early transcriptional changes in vivo in response to progesterone withdrawal. This greatly increases our understanding of the pathways leading to menstruation and may provide new approaches to diagnose and treat menstrual disorders.

Changes in platelet function, hemostasis, and prostaglandin expression after treatment with nonsteroidal anti-inflammatory drugs with various cyclooxygenase selectivities in dogs

OBJECTIVE

To determine the effects of nonsteroidal anti-inflammatory drugs of various cyclooxygenase selectivities on hemostasis and prostaglandin expression in dogs.

ANIMALS

8 client-owned dogs with clinical signs of osteoarthritis.

PROCEDURES

Dogs received aspirin (5 mg/kg, PO, q 12 h), carprofen (4 mg/kg, PO, q 24 h), deracoxib (2 mg/kg, PO, q 24 h), and meloxicam (0.1 mg/kg, PO, q 24 h) for 10 days each, with an interval of at least 14 days between treatments. On days 0 and 10, blood was collected for platelet aggregation assays, thrombelastography, and measurement of lipopolysaccharide-stimulated prostaglandin E(2), platelet thromboxane B(2) (TXB(2)), and free serum TXB(2) and 6-keto-prostaglandin F (PGF)-1alpha concentrations.

RESULTS

Platelet aggregation decreased after treatment with aspirin and carprofen, whereas significant changes from baseline were not detected for the other drugs tested. Thrombelastograms obtained after treatment with carprofen revealed decreased maximum amplitude and alpha-angle, suggesting hypocoagulability. Maximum amplitude and coagulation index increased after treatment with deracoxib. Plasma concentrations of prostaglandin E(2) decreased after treatment with carprofen or deracoxib, and platelet TXB(2) production increased after treatment with aspirin. Serum concentrations of the prostacyclin metabolite 6-keto-PGF-1alpha did not change significantly after treatment with any of the drugs, although the ratio of free TXB(2) to 6-keto-PGF-1alpha decreased slightly after treatment with carprofen and increased slightly after treatment with deracoxib.

CONCLUSIONS AND CLINICAL RELEVANCE

At the dosages tested, treatment with meloxicam affected platelet function minimally in dogs with osteoarthritis. Treatment with carprofen decreased clot strength and platelet aggregation. Clot strength was increased after treatment with deracoxib.

Genetic variability in prostaglandin synthesis, fish intake and risk of colorectal polyps

Dietary polyunsaturated fatty acids (PUFAs) can be converted to prostaglandins and leukotrienes. Metabolism of omega-6 (n-6) PUFAs results in the production of pro-inflammatory mediators whereas downstream products of omega-3 (n-3) PUFAs have lower inflammatory activity. Elevated n-3 PUFA intake from dietary fish may be associated with lower risk of colorectal neoplasia among those with genetic variants resulting in higher levels of pro-inflammatory mediators. We investigated interactions between dietary fish intake and polymorphisms in cyclooxygenase (COX)-1, COX-2, ALOX5 and PGIS in a case-control study of adenomas (N = 522), hyperplastic polyps (N = 194) and polyp-free controls (N = 626). Polyp risk did not differ by fish intake. A suggested interaction with fish intake was observed for COX-1 P17L. Among those who were homozygous wild type, increasing fish intake was associated with a modestly reduced risk of adenoma, whereas among those with at least one variant allele, the reverse trend was observed (p-interaction = 0.08). The interaction was statistically significant when non-steroidal anti-inflammatory drug (NSAID) use was also taken into account: among those with COX-1 17PP genotypes, high fish intake and regular NSAID use was associated with a decreased risk compared with low fish intake and low NSAID use (odds ratio = 0.60, 95% confidence interval 0.33-1.09). The opposite association was observed among those with COX-1 17PL or LL genotypes (p-interaction = 0.04). Our results suggest that the effects of dietary n-3 PUFA intake and NSAID use may differ by genetic variation in COX-1.

Pregnancy, Bovine Somatotropin, and Dietary n-3 Fatty Acids in Lactating Dairy Cows: II. Endometrial Gene Expression Related to Maintenance of Pregnancy

The objectives were to examine the effects of bovine somatotropin (bST), pregnancy, and dietary fatty acids on expression of key endometrial genes and proteins regulating prostaglandin synthesis in lactating dairy cows. Two diets were fed, at about 17 d in milk (DIM), in which oil of whole cottonseed (control diet) was compared with calcium salts of fish oil-enriched lipid (FO). Ovulation was synchronized in cows with a presynchronization plus Ovsynch protocol and cows were inseminated artificially or not inseminated on d 0 (d 0 = time of synchronized ovulation; 77 +/- 12 DIM). On d 0 and 11, cows received bST (500 mg) or no bST, and were slaughtered on d 17 to recover uterine secretions and endometrial tissue. Number of cows in the control diet: 5 bST-treated cyclic (bST-C), 5 non-bST-treated cyclic (no bST-C), 4 bST-treated pregnant (bST-P), and 5 non-bST-treated pregnant (no bST-P) cows and in the FO diet: 4 bST-treated FO-cyclic (bST-FO-C) and 5 non-bST-treated cyclic (no bST-FO-C) cows. The FO diet increased progesterone receptor (PR) mRNA, and treatment with bST increased PR mRNA concentration in endometrium of no bST-C, but not in no bST-FO-C or no bST-P cows. Concentrations of estrogen receptor-alpha (ERalpha) mRNA and protein, and oxytocin receptor (OTR) mRNA were decreased in no bST-P cows compared with no bST-C cows. Treatment with bST tended to increase OTR and ERalpha mRNA concentrations in cyclic cows fed control or FO diets. Immunohistochemistry demonstrated effects of bST, FO, and pregnancy on distributions of ERalpha and PR proteins in endometrium. Pregnancy and FO feeding decreased ERalpha abundance in luminal epithelium. Prostaglandin H synthase-2 (PGHS-2) protein was elevated in pregnant cows and localized to the luminal epithelium. Both FO and bST treatments reduced staining intensity of PGHS-2 protein. Concentrations of prostaglandin E synthase mRNA were elevated in either cyclic or pregnant cows in response to bST, whereas bST decreased prostaglandin F synthase mRNA in pregnant cows. Uterine lumen fluids had more PGF2alpha and prostaglandin E2 in pregnant than cyclic cows. Uterine lumen fluids of bST-P cows contained more prostaglandin E2 than those from no bST-P cows. In summary, both pregnancy and bST altered endometrial gene expression, and cyclic cows responded differently to bST than pregnant cows. Feeding FO modulated PR, ERalpha, and PGHS-2 expression and distribution among endometrial cell types in a manner that may favor establishment and maintenance of pregnancy.

Cyclooxygenase-1 and -2 enzymes differentially regulate the brain upstream NF-kappa B pathway and downstream enzymes involved in prostaglandin biosynthesis

We have recently reported that cyclooxygenase (COX)-2-deficiency affects brain upstream and downstream enzymes in the arachidonic acid (AA) metabolic pathway to prostaglandin E2 (PGE2), as well as enzyme activity, protein and mRNA levels of the reciprocal isozyme, COX-1. To gain a better insight into the specific roles of COX isoforms and characterize the interactions between upstream and downstream enzymes in brain AA cascade, we examined the expression and activity of COX-2 and phospholipase A2 enzymes (cPLA2 and sPLA2), as well as the expression of terminal prostaglandin E synthases (cPGES, mPGES-1, and - 2) in wild type and COX-1(-/-) mice. We found that brain PGE2 concentration was significantly increased, whereas thromboxane B2 (TXB2) concentration was decreased in COX-1(-/-) mice. There was a compensatory up-regulation of COX-2, accompanied by the activation of the NF-kappaB pathway, and also an increase in the upstream cPLA2 and sPLA2 enzymes. The mechanism of NF-kappaB activation in the COX-1(-/-) mice involved the up-regulation of protein expression of the p50 and p65 subunits of NF-kappaB, as well as the increased protein levels of phosphorylated IkappaBalpha and of phosphorylated IKKalpha/beta. Overall, our data suggest that COX-1 and COX-2 play a distinct role in brain PG biosynthesis, with basal PGE2 production being metabolically coupled with COX-2 and TXB2 production being preferentially linked to COX-1. Additionally, COX-1 deficiency can affect the expression of reciprocal and coupled enzymes, COX-2, Ca2+ -dependent PLA2, and terminal mPGES-2, to overcome defects in brain AA cascade.

IL-15 mediates immune inflammatory hypernociception by triggering a sequential release of IFN-gamma, endothelin, and prostaglandin

IL-15 is closely associated with inflammatory diseases. IL-15 targeting is effective in treating experimental and clinical rheumatoid arthritis (RA). Because hyperalgesia accompanies RA, we investigated the ability of IL-15 to induced nociceptor sensitization (hypernociception). We report here that IL-15 induced time- and dose-dependent mechanical hypernociception in mice. IL-15-induced hypernociception was inhibited by treatment with a dual endothelin receptor type A (ET(A))/endothelin receptor type B (ET(B)) antagonist (bosentan), ET(A) receptor antagonist (BQ123), or cyclooxygenase inhibitor (indomethacin). Moreover, IL-15 failed to induce hypernociception in IFN-gamma(-/-) mice, suggesting that IL-15 mediated hypernociception via an IFN-gamma-, endothelin (ET)-, and prostaglandin-dependent pathway. Consistent with this finding, IFN-gamma and ET-1 induced dose- and time-dependent mechanical hypernociception that was inhibited by BQ123 or indomethacin but not BQ788 (an ET(B) receptor antagonist). IFN-gamma induced the production of ET-1 and the expression of its mRNA precursor (preproET-1, PPET-1). Moreover, IL-15 also induced ET-1 production and PPET-1 mRNA expression in an IFN-gamma-dependent manner. Prostaglandin E(2) (PGE(2)) production was induced by IL-15, IFN-gamma, or ET-1. We also found that hypernociception induced by ovalbumin (OVA) in OVA-immunized mice was significantly diminished by treatment with sIL-15Ralpha (soluble IL-15 receptor alpha-chain), bosentan, BQ123, or indomethacin. Furthermore, OVA challenge induced the expression of PPET-1 mRNA in WT mice but not in IFN-gamma(-/-) mice. The PPET-1 mRNA expression was also inhibited by sIL-15Ralpha pretreatment. Therefore, our results demonstrate the sequential mechanical hypernociceptive effect of IL-15 --> IFN-gamma --> ET-1 --> PGE(2) and suggest that these molecules may be targets of therapeutic intervention in antigen-induced hypernociception.

Functional genomics of innate host defense molecules in normal human monocytes in response to Aspergillus fumigatus

Aspergillus fumigatus induces the release of innate immune-related molecules from phagocytic cells early in the course of infection. Little is known, however, about the complex expression profiles of the multiple genes involved in this response. We therefore investigated the kinetics of early gene expression in human monocytes (HMCs) infected with conidia of A. fumigatus using DNA microarray analysis. Total RNA from HMCs at 0, 2, 4, and 6 h was extracted, linearly amplified, hybridized onto Affymetrix HG133 Plus 2.0 gene chips, and analyzed with an Affymetrix scanner. Changes in gene expression were calculated as a ratio of those expressed by infected versus control HMCs. Aspergillus fumigatus induced differential regulation of expression in 1,827 genes (P < 0.05). Genes encoding cytokines and chemokines involved in host defense against A. fumigatus, including interleukin-1beta (IL-1beta), IL-8, CXCL2, CCL4, CCL3, and CCL20, as well as the opsonin long pentraxin 3, were up-regulated during the first 2 to 6 h, coinciding with an increase in phagocytosis. Simultaneously, genes encoding CD14, ficolin1, and MARCO were down-regulated, and genes encoding IL-10 and matrix metalloproteinase 1 were up-regulated. Up-regulation of the genes encoding heat shock proteins 40 and 110 and connexins 26 and 30 may point to novel molecules whose role in the pathogenesis of aspergillosis has not been previously reported. Verification of the transcriptional profiling was obtained for selected genes by reverse transcription-PCR and enzyme immunoassay. Thus, A. fumigatus conidia induced a coordinated expression of genes important in host defense and immunomodulation.

Prostanoid signal transduction and gene expression in the endothelium: role in cardiovascular diseases

Endothelial cells play an active role in the maintenance of homeostasis. Endothelial injury can give rise to endothelial dysfunction in which the profile of mediators released by endothelial cells is altered. Among these mediators are factors that participate in the development of many cardiovascular disorders. Some of the most important are the prostanoids, which can modulate the progression of atherosclerosis, arterial hypertension, and angiogenesis. Prostanoids are produced by the sequential actions of cyclooxygenases and specific synthases and exert their actions through diverse cell-surface and nuclear receptors. The profile of prostanoids produced depends on cell type and the changing pathophysiological status, and these factors similarly affect the great array of biological responses elicited by these molecules. The resulting complexity enables extremely subtle and highly complex responses, and this provides opportunities for the development of targeted therapeutic approaches.

Sufficient Progesterone-Priming Prior to Estradiol Stimulation Is Required for Optimal Induction of the Cervical Prostaglandin System in Pregnant Sheep at 0.7 Gestations1

The purposes of this study were to determine the separate and interactive functions of progesterone and estradiol in regulating the cervical prostaglandin (PG) system in pregnant sheep at 0.7 gestations. At 106-108 days of gestational age (dGA), ewes were treated with vehicle for 14 days (n = 5) or vehicle for 12 days followed by estradiol 5 mg twice a day, intramuscularly for 2 days (n = 5) or progesterone 100 mg, twice a day, intramuscularly for 14 days (n = 5) or progesterone 100 mg twice a day, intramuscularly for 10 days and then 2 days vehicle followed by estradiol 5 mg twice a day intramuscularly for 2 days (n = 5). At 121-123 dGA, cervical tissues were obtained under halothane anesthesia. Cervical RNA and protein were extracted and analyzed for prostaglandin-endoperoxide synthase 2 (COX2), two PGE(2) receptors, PTGER2 and PTGER4, and estrogen receptor alpha (ESR1) by Northern and Western blot analysis. Immunocytochemistry and in situ hybridization were applied to localize cellular distribution of COX2, PTGER2, and PTGER4 in the cervix. Data were analyzed by ANOVA. COX2 and PTGER4 mRNAs and proteins were increased (P < 0.05) in ewes treated with combined estradiol and progesterone but not in ewes treated with estradiol or progesterone alone compared with controls. ESR1 mRNA was increased in ewes treated with progesterone and estradiol plus progesterone. In contrast, PTGER2 mRNA and protein remained the same after all treatments. COX2 mRNA and protein were localized only in cervical glandular epithelial cells, whereas PTGER2 and PTGER4 were localized in both cervical glandular epithelial and smooth muscle cells. In conclusion, these data suggest that additional progesterone priming at 0.7 gestations synergizes with estradiol to induce cervical COX2, PTGER4, and ESR1 and support our hypothesis that stimulation of the cervical PG system by estradiol is optimized by sufficient progesterone priming in the pregnant sheep cervix.

The expression of cyclooxygenase-2, VEGF and PGs in CIN and cervical carcinoma

OBJECTIVE

To study the expression of cyclooxygenase-2 (COX-2), vascular endothelial growth factor (VEGF) and prostaglandins (PGs) in cervical tissues of differential pathological types, especially in cervical intraepithelial neoplasia (CIN) and cervical carcinoma, and their possible relationships in carcinogenesis.

METHODS

Tissue blocks and blood samples from 20 normal cervix women, 20 cervix inflammation patients, 20 CIN patients and 40 patients with cervical carcinoma, respectively, at our institutions from February 2000 to March 2002 were available for this study. COX-2 mRNA was examined by reverse transcription-polymerase chain reaction (RT-PCR). COX-2 and VEGF proteins were measured by immunohistochemistry using monoclonal antibodies to them. PGs (PGE2, TXB2, 6-k-PGF(1alpha)) were detected by radioimmunoassay (RIA).

RESULT

The overall positive expression of COX-2 and the quantity of PGs, especially PGE2 in inflammation, CIN and cervical carcinoma was higher and much higher than that in normal cervix (P < 0.001), There was a close relationship between COX-2 and PGs. The positive expression rate of VEGF in cervical carcinoma was higher than that in normal, inflammatory and CIN cervix, respectively (P < 0.001). VEGF protein was occasionally expressed in CIN cervix (15%). There was no association among COX-2, VEGF and clinicopathological parameters in cervical carcinoma. The expression of COX-2 and VEGF in cases with tumor in diameter more than 4 cm (90.9%, 72.7%) was higher than those with smaller tumor (86.2%, 51.7%).

CONCLUSIONS

The COX-2 probably is a gene involved early in carcinogenesis of cervical carcinoma by increase of PGs, and accelerates the progress of tumor by increase of PGs and VEGF. Therefore testing the expression of PGs may be a prognosis marker for clinical diagnosis.

Gastric mucosal protection: from prostaglandins to gene-therapy

The maintenance of gastric mucosal function and integrity highly depends on the status of microcirculation. Vasoactive agents--prostaglandins, nitric oxide and sensory neuropeptides (e.g. calcitonin gene-related peptide)--play a crucial role in mucosal defensive processes. Beside the local release of vasoactive mediators the central nervous system is also involved in regulation of gastric functions. Cerebral lesions, stimulation of different brain areas can result in gastric mucosal injury. Noxious challenge of gastric mucosa alters the sodium currents in gastric sensory neurons and induces cfos mRNA expression in nucleus tractus solitarii and area postrema. Vagal nerve has long been established to play a permissive role in the development of gastric lesions. However, several lines of evidences suggest its physiological relevance in the enhancement of gastric mucosal resistance. It was concluded that gastroprotection can be induced by low level of central vagal stimulation and the consequent release of prostaglandins, nitric oxide, and calcitonin gene-related peptide. Prostaglandins, nitric oxide and sensory neuropeptides play a role also in ulcer healing by stimulating the formation of growth factors, the epithelial proliferation and angiogenesis. Both systemic and local administration of growth factors accelerated the ulcer healing. Local, single injection of plasmid-DNA encoding vascular endothelial growth factor (VEGF) was shown to stimulate the ulcer healing in the rat. The transient, local expression of VEGF in ulcerated tissue might be a new therapeutic strategy in the treatment of gastric ulcer disease.

Molecular characterization of the lipopolysaccharide/platelet activating factor- and zymosan-induced pathways leading to prostaglandin production in P388D1 macrophages

P388D1 cells release free arachidonic acid (AA) and prostaglandin E2 (PGE2) upon stimulation with platelet-activating factor (PAF) and zymosan. The response to PAF is dependent on priming of the cells with bacterial lipopolysaccharide (LPS). In the LPS/PAF pathway, both AA and PGE2 release are dependent on transcription and translation, whereas in the zymosan pathway the release of these compounds appears to be largely independent of these processes. Using quantitative real-time PCR, we analyzed the expression of mRNAs that encode proteins potentially responsible for the dependency of the LPS/PAF pathway on gene expression. These include all the phospholipases A2 (PLA2) that we detected in P388D1 cells, cyclooxygenases (COX), COX-1 and COX-2, the membrane-associated prostaglandin E synthase-1 (mPGES-1), the lipocalin-type prostaglandin D2 synthase (PGDS), hematopoietic PGDS and the subunit G(alpha i2) of heterotrimeric G-proteins. None of the mRNAs encoding PLA2s, PGDSs, or G(alpha i2) are substantially altered during LPS priming. However, cyclooxygenase-2 is up-regulated during LPS priming and after stimulation of the cells with zymosan. A modest but significant increase of mPGES-1 mRNA was also detected upon stimulation with zymosan. Thus, the dependency of the LPS/PAF-induced PGE2 production on gene expression can be attributed to the production of cyclooxygenase-2. The dependency of AA release on gene expression is not due to altered expression of any of the PLA2s. We suggest that an accessory regulatory protein affecting the release of AA must be responsible. Using HPLC we separated lipids that are secreted upon stimulation with LPS/PAF and zymosan and found that in both pathways PGD2 is the dominant prostaglandin produced and also detected PGE2, PGF(2alpha) and AA besides several unidentified compounds.

Defects in the prostaglandin system--what is known?

The central role of prostaglandins as local mediators is well accepted. Molecular biology and in particular knock-out mice models teach us a lot on mechanisms and eventual biological consequences. Despite the broad basic knowledge available, human data on defects in the prostaglandin system are extremely rare. Why? Don't we search for them? Are they of clinical relevance? What is their prevalence, the outcome? How to treat, if possible? For this purpose we are planning a platform and databank to improve knowledge, pool information and allow exchange of probes. All interested people are invited to join.

[Effects of selective cyclooxygenase-2 inhibitor NS-398 on 5-fluorouracil chemotherapy and progression of colon cells: an experimental study]

OBJECTIVE

To investigate the effects of selective cyclooxygenase-2 (COX-2) inhibitor NS-398 on 5-fluorouracil (5-Fu) chemotherapy and on the progression of colon cells.

METHODS

Colon cancer cells of HT-29 and SW480 lines were cultured. Selective COX-2 inhibitor NS-398, 5-Fu, or NS-398 combining with 5-Fu were added into the cultures to be co-cultured for 24, 48, and 72 hours respectively. RT-PCR and ELISA analysis were performed to detect the level of COX-2 mRNA expression and prostaglandin 2 (PGE2) concentration in the cells of both HT-29 and SW480 lines. The proliferation and apoptosis of the two cell lines were observed with MTT assay and flow cytometry.

RESULTS

Expression of COX-2 mRNA were negative in SW480 line and positive in HT-29 line. Compared with SW480 line, the HT-29 line showed an obvious decline of PGE2 concentration following NS-398 treatment. Both NS-398 and 5-Fu inhibited the cells' proliferation and induced apoptosis in a dose-dependent manner, and a more significant inhibition was found when the cells were co-treated with NS-398 and 5-Fu. Although, there was no significant difference between these in inducing apoptosis.

CONCLUSION

Selective COX-2 inhibitor NS-398 can inhibit the proliferation of colon cancer cells and induce apoptosis thereof. The mechanism of NS-398 against colon cancer may be independent upon the expression levels of COX-2 mRNA and PGE2 of colon cancer. NS-398 may be a subsidiary drug in 5-Fu chemotherapy in treating colon cancer.

Effect of folic acid plus glycine supplement on uterine prostaglandin and endometrial granulocyte-macrophage colony-stimulating factor expression during early pregnancy in pigs

The objective was to determine the effects of folic acid+glycine supplement on uterine metabolism of prostaglandin and mRNA expression of endometrial granulocyte-macrophage colony-stimulating factor (GM-CSF) in nulliparous (NYL) and multiparous Yorkshire-Landrace (YL) sows, and in multiparous Meishan-Landrace sows (ML). In each of these three groups, sows were randomly assigned to two treatments: 15 ppm folic acid+0.6% glycine or no supplement. The dietary supplement was given from the estrus before mating to slaughter on Day 25 of pregnancy. At slaughter, endometrial tissue was collected to determine endometrial expression levels of GM-CSF mRNA, cyclooxygenase-1 (COX1) and -2 (COX2) and to evaluate in vitro endometrial secretion of prostaglandin E2 (PGE2) secretion. Allantoic fluid samples were also collected to determine the concentration of PGE2, prostaglandin F2alpha (PGF2alpha), estradiol-17beta (E2), progesterone (P4), and transforming-growth factor-beta2 (TGF-beta2). The allantoic contents of PGF2alpha, E2 and P4, and endometrial in vitro secretion of PGE2 were not significantly influenced by the folic acid+glycine supplement. The folic acid+glycine supplement tended (P<0.07) to increase allantoic content of PGE2 and TGF-beta2 in all sows and increased (P<0.05) endometrial expression of COX2, especially in NYL sows. The endometrial expression of COX1 was decreased (P<0.05) by folic acid+glycine supplement, especially in multiparous YL sows. The allantoic contents of PGE2 and PGF2alpha were not significantly affected by sow type. However, NYL sows had higher (P<0.05) endometrial in vitro secretion of PGE2 and allantoic content of P4 than multiparous YL and ML sows. The allantoic content of E2 was also higher (P<0.05) in NYL sows than in multiparous ML sows only. The allantoic content of TGF-beta2 was lower (P<0.05) in multiparous ML than in multiparous YL only sows. Finally, in YL and NYL sows, folic acid+glycine supplement decreased (P<0.05) the endometrial expression of GM-CSF but not in ML sows. In summary, folic acid+glycine supplement altered endometrial expression of GM-CSF and uterine metabolism of prostaglandins during the post-attachment period of porcine embryos but some of these effects were manifest only in Meishan and nulliparous sows.

Transcriptional regulation of genes for enzymes of the prostaglandin biosynthetic pathway

Numerous studies over the years have demonstrated changes in prostaglandin (PG) levels in intrauterine tissues in association with labour, and PG administration has long been used to induce delivery. While it is now widely accepted that PGs play a major role in human parturition, the complex regulation of their levels is still being elucidated, with the focus on the transcriptional control of the enzymes responsible for the various steps in PG biosynthesis and catabolism.

Roles of connective tissue growth factor and prostanoids in early streptozotocin-induced diabetic rat kidney: the effect of aspirin treatment

BACKGROUND

Connective tissue growth factor (CTGF) is a cysteine-rich growth factor induced by transforming growth factor-beta (TGF-beta) and is thought to play a critical role in TGF-beta-stimulated extracellular matrix accumulation. To explore its involvement in early diabetic nephropathy, we investigated the time course of CTGF gene expression and its regulation in streptozotocin (STZ)-induced diabetic rat kidney.

METHODS

Northern blot analysis for CTGF, TGF-beta, and fibronectin expression was performed in the glomeruli of STZ-induced diabetic rats from 3 days to 12 weeks after the induction of diabetes, together with histological examination. To investigate the role of prostanoids in this process, aspirin was administered in one group of diabetic rats. Furthermore, CTGF expression was analyzed in rat mesangial cells cultured under high-glucose conditions.

RESULTS

Glomerular expression of CTGF and TGF-beta1 mRNA was coordinately upregulated as early as day 3, followed by fibronectin induction and mesangial matrix accumulation. Chronic aspirin treatment in diabetic rats significantly attenuated mesangial expansion, and effectively suppressed CTGF induction, as well as inhibiting the upregulation of TGF-beta1 and fibronectin expression. In cultured mesangial cells, aspirin treatment abolished high glucose-stimulated CTGF upregulation.

CONCLUSIONS

These results indicate that CTGF expressed in the glomeruli is upregulated in the early stage of STZ-induced diabetic nephropathy in rats, and could be a critical mediator of the development of diabetic glomerulosclerosis. In addition, the modulatory effects of aspirin during this process suggest a role of the cyclooxygenase pathway in the progression of diabetic nephropathy.

Fluid shear stress induction of COX-2 protein and prostaglandin release in cultured MC3T3-E1 osteoblasts does not require intact microfilaments or microtubules

Cultured osteoblasts express three major types of cytoskeleton: actin microfilaments, microtubules, and intermediate filaments. The cytoskeletal network is thought to play an important role in the transmission and conversion of a mechanical stimulus into a biochemical response. To examine a role for the three different cytoskeletal networks in fluid shear stress-induced signaling in osteoblasts, we individually disrupted actin microfilaments, micro-tubules, and intermediate filaments in MC3T3-E1 osteoblasts with multiple pharmacological agents. We subjected these cells to 90 min of laminar fluid shear stress (10 dyn/cm(2)) and compared the PGE(2) and PGI(2) release and induction of cyclooxygenase-2 protein to control cells with intact cytoskeletons. Disruption of actin microfilaments, microtubules, or intermediate filaments in MC3T3-E1 cells did not prevent a significant fluid shear stress-induced release of PGE(2) or PGI(2). Furthermore, disruption of actin microfilaments or microtubules did not prevent a significant fluid shear stress-induced increase in cyclooxygenase-2 protein levels. Disruption of intermediate filaments with acrylamide did prevent the fluid shear stress-induced increase in cyclooxygenase-2 but also prevented a PGE(2)-induced increase in cyclooxygenase-2. Thus none of the three major cytoskeletal networks are required for fluid shear stress-induced prostaglandin release. Furthermore, although neither actin microfilaments nor microtubules are required for fluid shear stress-induced increase in cyclooxygenase-2 levels, the role of intermediate filaments in regulation of cyclooxygenase-2 expression is less clear.

Enhancing radiotherapy with cyclooxygenase-2 enzyme inhibitors: a rational advance?

Results of preclinical studies suggesting that the efficacy of molecular therapies is enhanced when they are combined with radiation have generated a surge of clinical trials combining these modalities. We reviewed the literature to identify the rationale and experimental foundation supporting the use of cyclooxygenase-2 (COX-2) inhibitors with standard radiotherapy regimens in current clinical trials. Radiation affects the ability of cells to divide and proliferate and induces the expression of genes involved in signaling pathways that promote cell survival or trigger cell death. Future advances in radiotherapy will hinge on understanding mechanisms by which radiation-induced transcription of genes governs cell death and survival, the selective control of this process, and the optimal approaches to combining this knowledge with existing therapeutic modalities. COX-2 is expressed in all stages of cancer, and in several cancers its overexpression is associated with poor prognosis. Evidence from clinical and preclinical studies indicates that COX-2-derived prostaglandins participate in carcinogenesis, inflammation, immune response suppression, apoptosis inhibition, angiogenesis, and tumor cell invasion and metastasis. Clinical trial results have demonstrated that selective inhibition of COX-2 can alter the development and the progression of cancer. In animal models, selective inhibition of COX-2 activity is associated with the enhanced radiation sensitivity of tumors without appreciably increasing the effects of radiation on normal tissue, and preclinical evidence suggests that the principal mechanism of radiation potentiation through selective COX-2 inhibition is the direct increase in cellular radiation sensitivity and the direct inhibition of tumor neovascularization. Results of current early-phase studies of non-small-cell lung, esophageal, cervical, and brain cancers will determine whether therapies that combine COX-2 inhibitors and radiation will enter randomized clinical trials.

Role of heme oxygenase-1 protein in the neuroprotective effects of cyclopentenone prostaglandin derivatives under oxidative stress

Previously we found that some cyclopenteone prostaglandin derivatives (PGs), referred to as neurite outgrowth-promoting PGs (NEPPs), have dual biological activities of promoting neurite outgrowth and preventing neuronal death [Satoh et al. (2000) J. Neurochem., 75, 1092-1102; Satoh et al. (2001) J. Neurochem., 77, 50-62; Satoh et al. (2002) In Kikuchi, II. (ed.), Strategenic Medical Science Against Brain Attack. Springer-Verlag, Tokyo, pp. 78-93]. To investigate possible cellular mechanisms of the neuroprotective effects, we performed oligo hybridization-based DNA array analysis with mRNA isolated from HT22, a cell line that originated from a mouse hippocampal neuron. Several transcripts up-regulated by NEPP11 were identified. Because heme oxygenase 1 (HO-1) mRNA was the most prominently induced and was earlier reported to protect neuronal and non-neuronal cells against oxidative stress, we focused on it as a possible candidate responsible for the neuroprotective effects. We found NEPP11 to induce HO-1 protein (32 kDa) in HT22 cells in both the presence and the absence of glutamate, whereas non-neuroprotective prostaglandins (PGs) Delta12-PGJ2 or PGA2 did not. Overexpression of HO-1-green fluorescence protein (GFP) fusion protein significantly protected HT22 cells against oxidative glutamate toxicity, whereas that of GFP alone did not. Furthermore, biliverdin and bilirubin, products of HO-1 enzymatic activity on heme, protected HT22 cells from oxidative glutamate toxicity. These results, together with our previous results, suggest that NEPP11 activates the expression of HO-1 and that HO-1 produces biliverdin and bilirubin, which result in the inhibition of neuronal death induced by oxidative stress. NEPP11 is the first molecular probe reported to have a neuroprotective action through induction of HO-1 in neuronal cells.

Nuclear prostaglandin signaling system: biogenesis and actions via heptahelical receptors

Prostaglandins are ubiquitous lipid mediators that play pivotal roles in cardiovascular homeostasis, reproduction, and inflammation, as well as in many important cellular processes including gene expression and cell proliferation. The mechanism of action of these lipid messengers is thought to be primarily dependent on their interaction with specific cell surface receptors that belong to the heptahelical transmembrane spanning G protein-coupled receptor superfamily. Accumulating evidence suggests that these receptors may co-localize at the cell nucleus where they can modulate gene expression through a series of biochemical events. In this context, we have recently demonstrated that prostaglandin E2-EP3 receptors display an atypical nuclear compartmentalization in cerebral microvascular endothelial cells. Stimulation of these nuclear EP3 receptors leads to an increase of eNOS RNA in a cell-free isolated nuclear system. This review will emphasize these findings and describe how nuclear prostaglandin receptors, notably EP3 receptors, may affect gene expression, specifically of eNOS, by identifying putative transducing elements located within this organelle. The potential sources of lipid ligand activators for these intracellular sites will also be addressed. The expressional control of G-protein-coupled receptors located at the perinuclear envelope constitutes a novel and distinctive mode of gene regulation.

Altered prostanoid production by fibroblasts cultured from the lungs of human subjects with idiopathic pulmonary fibrosis

BACKGROUND

Prostanoids are known to participate in the process of fibrogenesis. Because lung fibroblasts produce prostanoids and are believed to play a central role in the pathogenesis of idiopathic pulmonary fibrosis (IPF), we hypothesized that fibroblasts (HF) cultured from the lungs of patients with IPF (HF-IPF) have an altered balance between profibrotic (thromboxane [TX]A2) and antifibrotic (prostacyclin [PGI2]) prostaglandins (PGs) when compared with normal human lung fibroblasts (HF-NL).

METHODS

We measured inducible cyclooxygenase (COX)-2 gene and protein expression, and a profile of prostanoids at baseline and after IL-1beta stimulation.

RESULTS

In both HF-IPF and HF-NL COX-2 expression was undetectable at baseline, but was significantly upregulated by IL-1beta. PGE2 was the predominant COX product in IL-1beta-stimulated cells with no significant difference between HF-IPF and HF-NL (28.35 [9.09-89.09] vs. 17.12 [8.58-29.33] ng/10(6) cells/30 min, respectively; P = 0.25). TXB2 (the stable metabolite of TXA2) production was significantly higher in IL-1beta-stimulated HF-IPF compared to HF-NL (1.92 [1.27-2.57] vs. 0.61 [0.21-1.64] ng/10(6) cells/30 min, respectively; P = 0.007) and the ratio of PGI2 (as measured by its stable metabolite 6-keto-PGF1alpha) to TXB2 was significantly lower at baseline in HF-IPF (0.08 [0.04-0.52] vs. 0.12 [0.11-0.89] in HF-NL; P = 0.028) and with IL-1beta stimulation (0.24 [0.05-1.53] vs. 1.08 [0.51-3.79] in HF-NL; P = 0.09).

CONCLUSION

An alteration in the balance of profibrotic and antifibrotic PGs in HF-IPF may play a role in the pathogeneses of IPF.

The origin of 15R-prostaglandins in the Caribbean coral Plexaura homomalla: molecular cloning and expression of a novel cyclooxygenase

The highest concentrations of prostaglandins in nature are found in the Caribbean gorgonian Plexaura homomalla. Depending on its geographical location, this coral contains prostaglandins with typical mammalian stereochemistry (15S-hydroxy) or the unusual 15R-prostaglandins. Their metabolic origin has remained the subject of mechanistic speculations for three decades. Here, we report the structure of a type of cyclooxygenase (COX) that catalyzes transformation of arachidonic acid into 15R-prostaglandins. Using a homology-based reverse transcriptase--PCR strategy, we cloned a cDNA corresponding to a COX protein from the R variety of P. homomalla. The deduced peptide sequence shows 80% identity with the 15S-specific coral COX from the Arctic soft coral Gersemia fruticosa and approximately 50% identity to mammalian COX-1 and COX-2. The predicted tertiary structure shows high homology with mammalian COX isozymes having all of the characteristic structural units and the amino acid residues important in catalysis. Some structural differences are apparent around the peroxidase active site, in the membrane-binding domain, and in the pattern of glycosylation. When expressed in Sf9 cells, the P. homomalla enzyme forms a 15R-prostaglandin endoperoxide together with 11R-hydroxyeicosatetraenoic acid and 15R-hydroxyeicosatetraenoic acid as by-products. The endoperoxide gives rise to 15R-prostaglandins and 12R-hydroxyheptadecatrienoic acid, identified by comparison to authentic standards. Evaluation of the structural differences of this 15R-COX isozyme should provide new insights into the substrate binding and stereospecificity of the dioxygenation reaction of arachidonic acid in the cyclooxygenase active site.

Pregnancy, parturition, and prostaglandins: defining uterine leiomyomas

Leiomyomas, benign smooth muscle tumors of the uterus, are the most common gynecologic neoplasm in women. Studies with surgically resected human tissues and primary cultures have revealed that several genes are differentially expressed in leiomyomas compared to matched normal myometrium. An estrogen-driven pattern of gene expression in leiomyomas, similar to that seen in normal myometrium during pregnancy and parturition, is associated with a persistent inappropriate response of neoplastic myometrial smooth muscle cells to ovarian hormones. This is possibly due to aberrant expression levels or signaling via estrogen and progesterone receptors. We propose the hypothesis that uterine leiomyomas mimic a differentiated myometrial cell at pregnancy and exhibit a hypersensitivity to sex steroid hormones that prevents the cells from responding to normal apoptotic or dedifferentiation signals and from returning to a nongravid phenotype. Support of this hypothesis is derived from experimental studies in female Eker rats that develop uterine leiomyomas with many similarities to the human disease. Our hypothesis accounts for the benign nature of these tumors and their high incidence in women during the reproductive years. By identifying the factors that participate in parturition and involution of the pregnant myometrium, we may better define uterine leiomyomas and thus identify novel targets for therapeutic strategies to treat these tumors.

Roles of prostanoids revealed from studies using mice lacking specific prostanoid receptors

The actions of prostanoids in various physiological and pathophysiological conditions have been being examined using mice lacking different prostanoid receptors. Prostaglandin (PG) I2 worked not only as a mediator of inflammation but also as an antithrombotic agent. PGF2alpha was found to be an essential inducer of labor. Several important actions of PGE2 are exerted via each of the four PGE2 receptor subtypes: EP1, EP2, EP3 and EP4. PGE2 participated in colon carcinogenesis via the EP1. PGE2 also participates in ovulation and fertilization and contributes to the control of blood pressure under high-salt intake via the EP2. PGE2 worked as a mediator of febrile responses to both endogenous and exogenous pyrogens and as a regulator of bicarbonate secretion induced by acid-stimulation in the duodenum via the EP3. It regulated the closure of ductus arteriosus and showed bone resorbing action via the EP4. PGD2 was found to be a mediator of allergic asthma. These studies have revealed important roles of prostanoids, some of which had not previously been known.

Expression of myometrial activation and stimulation genes in a mouse model of preterm labor: myometrial activation, stimulation, and preterm labor

Myometrial contractions of labor result from an increase in myometrial activation and stimulation. Activation develops through the expression of contraction associated proteins (CAPs), including oxytocin receptors (OTR), connexin-43 (Cx-43), and prostaglandin F2 alpha, receptors (FP). Stimulation involves increases in contractile agonists including prostaglandin E2 (PGE2) and prostaglandin F2 alpha. (PGF2 alpha) that may result from increases in prostaglandin endoperoxide H synthase (PGHS)-2. A mouse model of preterm birth was used to study gene expression involved in myometrial activation and stimulation. To induce preterm birth, pregnant C57BL/6J mice were intubated with 6 g/kg ethanol on gestational day 16 and were killed every 6 h from treatment until birth. RIA was used to measure uterine PGE2 and PGF2 alpha, while PGHS-2, OTR, Cx-43, and FP messenger RNA levels were measured by ribonuclease protection assay. Increases in CAP mRNA were associated with term and preterm birth. There were differences in stimulation effectors associated with preterm and term birth. Uterine PGF2 alpha values were increased only at the time of term birth, but PGE2 was elevated during both preterm and term labor. These data suggest that existing levels of PGF2 alpha are sufficient for preterm birth when CAP expression is increased, but term labor requires increases in PGE2, PGF2alpha, and CAPs. The PGHS-2 messenger RNA expression pattern suggests that it is a CAP.

Insight into prostaglandin, leukotriene, and other eicosanoid functions using mice with targeted gene disruptions

In recent years, there has been an exponential increase in the number of targeted gene disruptions performed in mice. At least 18 different gene knockouts have now been reported that have direct relevance to eicosanoid biology. These include genes that influence substrate availability (phospholipases), metabolism to eicosanoids (e.g., prostaglandin H synthases, lipoxygenases), and eicosanoid action (e.g., receptors for various prostaglandins). This minireview will outline the phenotype of these knockout mice and what has been learned about eicosanoid functions through use of this novel methodology.

Humoral regulation of physiological sleep: cytokines and GHRH

Interleukin-1, tumour necrosis factor, and growth hormone releasing hormone form part of the humoral mechanisms regulating physiological sleep. Their injection enhances non-rapid-eye-movement sleep whereas their inhibition reduces spontaneous sleep and sleep rebound after sleep deprivation. Changes in their mRNA levels and changes in their protein levels in the brain are consistent within their proposed role in sleep regulation. Furthermore, results from transgenic and mutant animals also are suggestive of their role in sleep regulation. The sites responsible for the growth hormone releasing hormone somnogenic activity seem to reside in the anterior hypothalamus/basal forebrain. Somnogenic sites for interleukin-1 and tumour necrosis factor likely include the anterior hypothalamus, but also may extend beyond that area. These substances elicit non-rapid-eye-movement sleep via a biochemical cascade that includes other known sleep regulatory substances.

The molecular biology and ocular distribution of prostanoid receptors

Enormous progress has been made in the characterization of prostanoid receptors during the past five years. Molecular biological studies have enabled structural identification of all the human prostanoid receptors that had been proposed according to pharmacological criteria. The pharmacological classification proposed different receptor subtypes for prostaglandins D2, E2, F2 alpha, I2 and thromboxane A2 which were termed DP, EP, FP, IP and TP, respectively. Further subdivision for only the EP receptor has been reported and EP1, EP2, EP3, and EP4 subtypes have been unequivocally identified. The molecular structure of all prostanoid receptors is typical of that for G protein-coupled receptors and consists of seven alpha-helical transmembrane domains, three extracellular loops and an amino terminus, and three intracellular loops and a carboxyl terminus. Interestingly, mRNA alternative splice variants of the carboxyl termini have been found to determine G protein interactions for the EP3 receptor. Application of molecular biological techniques is beginning to make an impact in ocular research, where precise localization of receptors is difficult by more traditional methods because of the diminutive size of most ocular tissues. In situ hybridization and immunohistochemical studies using antibodies against the cloned human FP receptor have already suggested an unexpectedly wide distribution in the monkey eye. Transgenic studies involving FP receptor knock-out animals may provide future insight into the role of this receptor in glaucoma. However, since prostaglandins are extraordinarily effective in reducing intraocular pressure, it follows that traditional physiological and pharmacological studies retain a key role in glaucoma research. Studies in perfused human anterior segment organ culture have revealed that although prostaglandin F2 alpha does not facilitate trabecular aqueous humor outflow, prostaglandin E1 does increase trabecular outflow. Thus, different prostanoids may lower intraocular pressure by distinctly different mechanisms of action. Recent studies also indicate that prostanoids may exert a beneficial effect on retinal blood perfusion and may even act as neuroprotective agents.

Prostanoid biosynthesis and mechanisms of action

Prostanoids are local hormones formed from arachidonic acid that coordinate responses to circulating hormones which elicit prostanoid synthesis. For example, in the kidney, prostaglandin (PG) E2 synthesized by collecting tubule epithelia in response to arginine vasopressin (AVP) acts on the parent collecting tubule as well as the neighboring thick limb to modulate NaCl and water reabsorption occurring in response to AVP. Studies performed over the last 15 years have defined the major cellular and subcellular sites of PG synthesis in the kidney. In addition, it is now recognized that the multiple cellular actions of prostanoids in the kidney are mediated through receptors coupled to guanine nucleotide regulatory proteins. The goal of this review is to summarize recent biochemical and molecular biological studies on prostanoid biosynthetic enzymes and on prostanoid receptors. The major topics to be addressed are 1) phospholipid precursors of arachidonate, 2) membrane-associated and cytosolic phospholipase A2s, 3) PG endoperoxide (PGH) synthase isozymes, 4) thromboxane A (TxA) synthase, and 5) TxA/PGH and PGE receptors.

A survey of six genetic markers on the populations of Punjab and Rajasthan (India)

190 Punjabis (Hindus and Sikhs) of Chandigarh and 152 Hindus of Jodhpur (Rajasthan) were examined for six genetic markers, four of which (APO C-II, C6, C7 and FXIIIA) were not studied before in Asiatic Indians. For APO C-II and C7 only the common phenotype was found in a total of 229 and 99 subjects, respectively. For the remaining four markers the two samples were pooled since the gene frequency estimates were not significantly different: FXIIIA*2 = 0.205 +/- 0.016; C6*B = 0.366 +/- 0.037; PGM1*2 = 0.247 +/- 0.017; PGD*C = 0.041 +/- 0.008. These data may contribute to evaluate the extent of the Mongoloid genetic admixture into the Caucasoid gene pool of the Punjab and Rajasthan Hindu population.