Demonstration of an inducible cyclooxygenase in human endothelial cells using antibodies raised against the carboxyl-terminal region of the cyclooxygenase-2

8-Prenylgenistein Isoflavone in Cheonggukjang Acts as a Novel AMPK Activator Attenuating Hepatic Steatosis by Enhancing the SIRT1-Mediated Pathway

8-Prenylgenistein (8PG), a genistein derivative, is present in fermented soybeans (Glycine max), including cheonggukjang (CGJ), and exhibits osteoprotective, osteogenic, and antiadipogenic properties. However, the hepatoprotective effects of 8PG and its underlying molecular mechanisms remain largely unexplored. Here, we identified the high binding affinity of 8PG with AMP-activated protein kinase (AMPK) and sirtuin 1 (SIRT1), which acts as a potent AMPK activator that counteracts hepatic steatosis. Notably, 8PG exhibited better pharmacokinetics with greater absorption and higher plasma binding than the positive controls for the target proteins. Moreover, 8PG exerted non-carcinogenic activity in rats and significantly increased AMPK phosphorylation. Compound C, an AMPK inhibitor, did not antagonize 8PG-activated AMPK in HepG2 cells. 8PG significantly attenuated palmitate-induced lipid accumulation and enhanced phosphorylated AMPK and its downstream target, acetyl-CoA carboxylase. Further, 8PG activated nuclear SIRT1 at the protein level, which promoted fatty acid oxidation in palmitate-treated HepG2 cells. Overall, 8PG acts as a potent AMPK activator, further attenuating hepatic steatosis via the SIRT1-mediated pathway and providing new avenues for dietary interventions to treat metabolic dysfunction-associated steatotic liver disease (MASLD).

Fluorinated Benzofuran and Dihydrobenzofuran as Anti-Inflammatory and Potential Anticancer Agents

Benzofuran and 2,3-dihydrobenzofuran scaffolds are heterocycles of high value in medicinal chemistry and drug synthesis. Targeting inflammation in cancer associated with chronic inflammation is a promising therapy. In the present study, we investigated the anti-inflammatory effects of fluorinated benzofuran and dihydrobenzofuran derivatives in macrophages and in the air pouch model of inflammation, as well as their anticancer effects in the human colorectal adenocarcinoma cell line HCT116. Six of the nine compounds suppressed lipopolysaccharide-stimulated inflammation by inhibiting the expression of cyclooxygenase-2 and nitric oxide synthase 2 and decreased the secretion of the tested inflammatory mediators. Their IC₅₀ values ranged from 1.2 to 9.04 µM for interleukin-6; from 1.5 to 19.3 µM for Chemokine (C-C) Ligand 2; from 2.4 to 5.2 µM for nitric oxide; and from 1.1 to 20.5 µM for prostaglandin E₂. Three novel synthesized benzofuran compounds significantly inhibited cyclooxygenase activity. Most of these compounds showed anti-inflammatory effects in the zymosan-induced air pouch model. Because inflammation may lead to tumorigenesis, we tested the effects of these compounds on the proliferation and apoptosis of HCT116. Two compounds with difluorine, bromine, and ester or carboxylic acid groups inhibited the proliferation by approximately 70%. Inhibition of the expression of the antiapoptotic protein Bcl-2 and concentration-dependent cleavage of PARP-1, as well as DNA fragmentation by approximately 80%, were described. Analysis of the structure-activity relationship suggested that the biological effects of benzofuran derivatives are enhanced in the presence of fluorine, bromine, hydroxyl, and/or carboxyl groups. In conclusion, the designed fluorinated benzofuran and dihydrobenzofuran derivatives are efficient anti-inflammatory agents, with a promising anticancer effect and a combinatory treatment in inflammation and tumorigenesis in cancer microenvironments.

Soyasapogenol C from Fermented Soybean (Glycine Max) Acting as a Novel AMPK/PPARα Dual Activator Ameliorates Hepatic Steatosis: A Novel SANDA Methodology

(1) Background: Soyasapogenol C (SSC), a derivative of soyasapogenol B (SSB), is specifically found high in many fermented soybean (Glycine max) products, including Cheonggukjang (in Korean). However, the biological activities for preventing and treating hepatic steatosis, and the precise underlying mechanisms of SSC, remain to be explored. (2) Methods: A novel SANDA (structural screening, ADMET prediction, network pharmacology, docking validation, and activity evaluation) methodology was used to examine whether SSC exerts hepatoprotective effects in silico and in vitro. (3) Results: SSC had better ADMET characteristics and a higher binding affinity with predicted targets chosen from network pathway analysis than SSB. SSC induced the phosphorylation of AMP-activated protein kinase (AMPK) and stimulated the nuclear translocation of peroxisome proliferator-activated receptor alpha (PPARα), further enhancing PPAR response element (PPRE) binding activity in HepG2 cells. Concurrently, SSC significantly inhibited triglyceride accumulation, which was associated with the suppression of lipogenesis genes and the enhancement of fatty acid oxidation gene expression in HepG2 cells. (4) Conclusions: Soyasapogenol C, discovered using a novel SANDA methodology from fermented soybean, is a novel AMPK/PPARα dual activator that is effective against hepatic steatosis. Dietary supplementation with soyasapogenol C may prevent the development of hepatic steatosis and other diseases associated with fat accumulation in the liver.

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

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

Chemical Composition, Antioxidant and Anti-inflammatory Activity Evaluation of the Lebanese Propolis Extract

Background:

Propolis is a resinous substance produced by bees and known to possess antioxidant, antimicrobial, antiproliferative and anti-inflammatory activities.

Objective:

This study is aimed at evaluating the in vivo and in vitro anti-inflammatory potential of the Crude Ethanolic Extract (CE) of Lebanese propolis and its Ethyl Acetate Fraction (EAF).

Method:

Chemical content of propolis was characterized using high-performance liquid chromatography and LC-MS/MS. COX-2 and iNOS protein expression, nitric oxide (NO) and prostaglandin (PGE2) release in LPS-activated RAW monocytes were achieved respectively by western blot and spectrophotometry. Antioxidant activity was evaluated by DPPH free radical scavenging assay. Measurement of paw thickness in carrageenan-induced paw edema in mice and pathologic assessment of inflammation in paw sections were used to judge the anti-inflammatory properties of propolis.

Results:

Pathology analysis revealed in the treated group significant reduction of immune cell infiltration and edema. Both extract and ethyl acetate fraction showed significant anti-inflammatory and antioxidant effects in LPS-treated RAW cells characterized by the inhibition of COX-2 and iNOS protein expression, as well as PGE2 and NO release. Chemical analysis of the crude extract and its ethyl acetate fraction identified 28 different compounds of which two phenolic acids and nine other flavonoids were also quantified. Ferulic acid, caffeic acid, chrysin, galangin, quercetin, and pinocembrin were among the most representative compounds.

Conclusion:

Lebanese propolis is rich in a various amount of flavonoids which showed promising antiinflammatory and antioxidant properties. Additionally, chemical analysis showed unique chemical compositions with the potential of identifying ingredients with interesting anti-inflammatory activities.

Palmitate induces glycosylation of cyclooxygenase-2 in primary human vascular smooth muscle cells

Vascular basal cyclooxygenase-2 (COX-2) expression and activity can be induced by endotoxin, hypoxia, or ischemia. During vascular pathologies such as atherosclerosis, increases in COX-2 activity result in prostanoid production, a contributor to the development and progression of vascular inflammation leading to unstable atherosclerotic plaques and increased risk for thrombotic events. Recent studies demonstrate that select free fatty acids, such as palmitate, can act as proinflammatory mediators. However, the effect of palmitate on COX-2 expression and activity, and its impact on the development and progression of vascular inflammation, are not well elucidated. We investigated the effect of palmitate on COX-2 expression and function in human vascular smooth muscle cells. Cells were treated with palmitate, COX-2 protein levels were assessed using Western analysis, and activity was assessed via ELISA. We observed that palmitate dose-dependently increased COX-2 levels and specifically enhanced band intensity of the COX-2 74 kDa band (slowest migrating band). This response was attenuated by N-linked glycosylation inhibition, suggesting that palmitate impacts expression of the fully activated glycoform of COX-2. Palmitate-induced increases in COX-2 levels correlated with an increase in prostaglandin E₂ production that was also attenuated by a glycosylation inhibitor. Additionally, palmitate altered cell morphology and increased cell density which were reversed by selective COX-2 inhibition. Thus, we conclude that palmitate acts on COX-2 by two separate mechanisms of action in human vascular smooth muscle. It elicits dose-dependent increases in COX-2 protein expression and modulates regulation of COX-2 activity via modification of posttranslational glycosylation.

Effect of betaine on hepatic insulin resistance through FOXO1-induced NLRP3 inflammasome

In the present study, we attempted to elucidate whether molecular modulation of inflammation by betaine through the forkhead box O1 (FOXO1)-induced NLRP3 inflammasome improves insulin resistance. Betaine is a major water-soluble component of Lycium chinense. It mainly functions as an oxidative metabolite of choline by suppressing superoxide-induced free radicals by donating methyl groups. The FOXO1 transcription factor regulates various genes involved in cellular metabolic processes related to cell death as well as oxidative stress responses through binding to the thioredoxin-interacting protein (TXNIP). Betaine is known to inhibit FOXO1 phosphorylation through phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT) in liver cells exposed to insulin. To elucidate the molecular mechanism of inactivation of insulin-induced FOXO1 by the antioxidant betaine, we used HepG2 cells and the liver of db/db mice treated with betaine at a dose of 50 mg/kg/day for 3 weeks. We found that the activation of NLRP3 inflammasome genes was reduced by betaine, which resulted in the suppression of reactive species (RS) production in liver cells. In addition, betaine inhibited insulin-induced PI3K/AKT and FOXO1 activation. Therefore, betaine suppressed the cytokine interleukin-1β production by inhibiting the activation of the NLRP3 inflammasome via interaction of FOXO1 and TXNIP. Our results suggest that betaine inhibits the FOXO1 binding to TXNIP, leading to the suppression of RS-induced NLRP3 inflammasome activation in a diabetic liver.

Free Radical-derived Oxysterols: Novel Adipokines Modulating Adipogenic Differentiation of Adipose Precursor Cells

CONTEXT

Increased oxidative stress in adipose tissue emerges as an inducer of obesity-linked insulin resistance. Here we tested whether free-radical derived oxysterols are formed by, and accumulate in, human adipocytes. Moreover, we asked whether increased accumulation of oxysterols characterizes the adipose cells of obese patients with type 2 diabetes (T2D) (OBT2D) compared with lean, nondiabetic controls (CTRLs). Finally, we studied the effects of the free radical-derived oxysterols on adipogenic differentiation of adipose-derived stem cells (ASCs).

MAIN OUTCOME MEASURES

Adipocytes and ASCs were isolated from sc abdominal adipose tissue biopsy in four OBT2D and four CTRL subjects. Oxysterols in adipocytes were detected by gas chromatography/mass spectrometry. The cellular and molecular effects of oxysterols were then evaluated on primary cultures of ASCs focusing on cell viability, adipogenic differentiation, and "canonical" WNT and MAPK signaling pathways.

RESULTS

7-ketocholesterol (7κ-C) and 7β-hydroxycholesterol were unambiguously detected in adipocytes, which showed higher oxysterol accumulation (P < .01) in OBT2D, as compared with CTRL individuals. Notably, the accumulation of oxysterols in adipocytes was predicted by the adipose cell size of the donor (R² = 0.582; P < .01). Challenging ASCs with free radical-derived type I (7κ-C) and type II (5,6-Secosterol) oxysterols led to a time- and concentration-dependent decrease of cell viability. Meaningfully, at a non-toxic concentration (1μM), these bioactive lipids hampered adipogenic differentiation of ASCs by sequential activation of WNT/β-catenin, p38-MAPK, ERK1/2, and JNK signaling pathways.

CONCLUSION

Free radical-derived oxysterols accumulate in the "diabetic" fat and may act as novel adipokines modulating the adipogenic potential of undifferentiated adipose precursor cells.

Signaling pathways involved in lipopolysaccharide stimulation of prostaglandin production by rat hypothalamic astroglial cells

The aim of this study was to investigate the mechanisms through which bacterial lipopolysaccharide (LPS) stimulates prostaglandin (PG) production in rat hypothalamic astroglial cells in vitro. The latter were treated with LPS alone or LPS plus antagonists of the interleukin-1 (IL-1) and nitric oxide (NO) pathways, and the subsequent changes in cyclooxygenase (COX) activity were monitored by measuring a COX end-product, prostaglandin E2 (PGE2), released into the incubation medium. LPS produced a concentration-dependent increase in PGE2 release from astroglia after 24 h incubation; experiments with selective antagonists showed that the increase in PGE 2 release induced by LPS may be, at least in part, mediated by IL-1 and NO.

Different Fatty Acids Compete with Arachidonic Acid for Binding to the Allosteric or Catalytic Subunits of Cyclooxygenases to Regulate Prostanoid Synthesis

Prostaglandin endoperoxide H synthases (PGHSs), also called cyclooxygenases (COXs), convert arachidonic acid (AA) to PGH2. PGHS-1 and PGHS-2 are conformational heterodimers, each composed of an (Eallo) and a catalytic (Ecat) monomer. Previous studies suggested that the binding to Eallo of saturated or monounsaturated fatty acids (FAs) that are not COX substrates differentially regulate PGHS-1 versus PGHS-2. Here, we substantiate and expand this concept to include polyunsaturated FAs known to modulate COX activities. Non-substrate FAs like palmitic acid bind Eallo of PGHSs stimulating human (hu) PGHS-2 but inhibiting huPGHS-1. We find the maximal effects of non-substrate FAs on both huPGHSs occurring at the same physiologically relevant FA/AA ratio of ∼20. This inverse allosteric regulation likely underlies the ability of PGHS-2 to operate at low AA concentrations, when PGHS-1 is effectively latent. Unlike FAs tested previously, we observe that C-22 FAs, including ω-3 fish oil FAs, have higher affinities for Ecat than Eallo subunits of PGHSs. Curiously, C-20 ω-3 eicosapentaenoate preferentially binds Ecat of huPGHS-1 but Eallo of huPGHS-2. PGE2 production decreases 50% when fish oil consumption produces tissue EPA/AA ratios of ≥0.2. However, 50% inhibition of huPGHS-1 itself is only seen with ω-3 FA/AA ratios of ≥5.0. This suggests that fish oil-enriched diets disfavor AA oxygenation by altering the composition of the FA pool in which PGHS-1 functions. The distinctive binding specificities of PGHS subunits permit different combinations of non-esterified FAs, which can be manipulated dietarily, to regulate AA binding to Eallo and/or Ecat thereby controlling COX activities.

Statins Modulate Cyclooxygenase-2 and Microsomal Prostaglandin E Synthase-1 in Human Hepatic Myofibroblasts

Statins have been shown to exert anti-inflammatory and anti-fibrogenic properties in the liver. In the present study, we explored the mechanisms underlying anti-fibrogenic effects of statins in isolated hepatic myofibroblasts and focused on cyclooxyegnase-2, a major anti-proliferative pathway in these cells. We show that simvastatin and fluvastatin inhibit thymidine incorporation in hMF in a dose-dependent manner. Pretreatment of cells with NS398, a COX-2 inhibitor, partially blunted this effect. cAMP levels, essential to the inhibition of hMF proliferation, were increased by statins and inhibited by non-steroidal anti-inflammatory drugs. Since statins modify prenylation of some important proteins in gene expression, we investigated the targets involved using selective inhibitors of prenyltransferases. Inhibition of geranylgeranylation resulted in the induction of COX-2 and mPGES-1. Using gel retardation assays, we further demonstrated that statins potentially activated the NFκB and CRE/E-box binding for COX-2 promoter and the binding of GC-rich regions and GATA for mPGES-1. Together these data demonstrate that statin limit hepatic myofibroblasts proliferation via a COX-2 and mPGES-1 dependent pathway. These data suggest that statin-dependent increase of prostaglandin in hMF contributes to its anti-fibrogenic effect.

Post-translational regulation of COX2 activity by FYN in prostate cancer cells

While increased COX2 expression and prostaglandin levels are elevated in human cancers, the mechanisms of COX2 regulation at the post-translational level are unknown. Initial observation that COX2 forms adduct with non-receptor tyrosine kinase FYN, prompted us to study FYN-mediated post-translational regulation of COX2. We found that FYN increased COX2 activity in prostate cancer cells DU145, independent of changes in COX2 or COX1 protein expression levels. We report that FYN phosphorylates human COX2 on Tyr 446, and while corresponding phospho-mimetic COX2 mutation promotes COX2 activity, the phosphorylation blocking mutation prevents FYN-mediated increase in COX2 activity.

Thiazole derivatives as inhibitors of cyclooxygenases in vitro and in vivo

Cyclooxygenases (COXs) are important membrane-bound heme containing enzymes important in platelet activation and inflammation. COX-1 is constitutively expressed in most cells whereas COX-2 is an inducible isoform highly expressed in inflammatory conditions. Studies have been carried out to evaluate thiazole derivatives as anti-inflammatory molecules. In this study, we investigated the in vitro and in vivo effects of two novel thiazole derivatives compound 1 (N-[4-(4-hydroxy-3-methoxyphenyl)-1,3-thiazol-2-yl] acetamide) and compound 2 (4-(2-amino-1,3-thiazol-4-yl)-2-methoxyphenol) on prostaglandin E2 (PGE2) production and COX activity in inflammatory settings. Our results reveal a potent inhibition of both compound 1 (IC50 9.01±0.01µM) and 2 (IC50 11.65±6.20µM) (Mean±S.E.M.) on COX-2-dependent PGE2 production. We also determined whether COX-1 activity was inhibited. Using cells stably over-expressing COX-1 and human blood platelets, we showed that compound 1 is a specific inhibitor of COX-1 with IC50 (5.56×10(-8)±2.26×10(-8)µM), whereas compound 2 did not affect COX-1. Both compounds exhibit anti-inflammatory effect in the dorsal air pouch model of inflammation as shows by inhibition of PGE2 secretion. Modeling analysis of docking in the catalytic site of COX-1 or COX-2 further confirmed the difference in the effect of these two compounds. In conclusion, this study contributes to the design of new anti-inflammatory agents and to the understanding of cyclooxygenase inhibition by thiazole.

Controlled reperfusion for different durations in the treatment of ischemia-reperfusion injury of the rat ovary: evaluation of biochemical features, molecular gene expression, and histopathology

High numbers of proinflammatory cells (PMNLs), which are carried by the blood to ischemic tissue during reperfusion, are considered responsible for inducing the inflammatory response that occurs in ischemia-reperfusion (I/R) injury. Our objective was to determine the controlled reperfusion (CR) interval duration (CRID) that would minimize the injury caused by the PMNLs that infiltrate ischemic tissue. Animal groups were divided into the following groups: Sham group, ovarian I/R group (OIR), and ovarian ischemia controlled-reperfusion groups OICR-1, OICR-2, OICR-3, OICR-4, OICR-5, OICR-6, which had their ovarian artery opened and then closed for 10, 8, 6, 4, 2, or 1 s, respectively. The results show that the COX-2 activity and the gene expression decreased while the COX-1 activity and the gene expression were found to be increased in parallel to the shortening of the period in CRID. From the histopathological examinations, the findings of hemorrhage, edema, congested vascular structures, degenerated cells, and migration and adhesion of PMNLs were scaled as follows: Sham group < OICR-6 < OICR-5 < OICR-4 < OICR-3 < OICR-2 < OICR-1. The results from the histopathological assessments were consistent with the molecular and biochemical findings. In conclusion, our findings suggest that increased COX-2 activity plays a role in I/R injury of the rat ovary, and that controlled reperfusion for 3, 2, or 1 s following 2 h of ischemia may attenuate the effects of I/R injury.

Anti-wrinkle effect of magnesium lithospermate B from Salvia miltiorrhiza BUNGE: inhibition of MMPs via NF-kB signaling

Skin is in direct contact with the environment and therefore undergoes aging as a consequence of environmentally induce damage. Wrinkle formation is a striking feature of intrinsic and photo-induced skin aging, which are both associated with oxidative stress and inflammatory response. The present study was undertaken to identify the mechanisms responsible for the anti-wrinkle effects of MLB, and thus, we investigated whether magnesium lithospermate B (MLB) from Salvia miltiorrhiza BUNGE associated with wrinkle formation caused by intrinsic and extrinsic skin aging using Sprague-Dawley rats aged 5 and 20 months and ultraviolet B (UVB)-irradiated human skin fibroblasts cells, respectively. The results obtained showed that the oral administration of MLB significantly upregulated the level of type I procollagen and downregulated the activities and expressions of matrix-metalloproteinases (MMPs) in rat skin. In fibroblasts, MLB suppressed the transactivation of nuclear factor-kB (NF-kB) and activator protein 1(AP-1), which are the two transcription factors responsible for MMP expression, by suppressing oxidative stress and the mitogen activated protein kinase (MAPK) pathway. Our results show that the antioxidant effect of MLB is due to the direct scavenging of reactive oxygen species (ROS) and its inhibitory effects on NF-kB-dependent inflammation genes, such as, cyclooxygenase-2 and inducible nitric oxide synthase. MLB was found to reverse both age- and UVB-related reductions in skin procollagen levels by suppressing the expressions and activities of NF-kB and AP-1-dependent MMPs by modulating ROS generation and the MAPK signaling pathway. We suggest that MLB potentially has anti-wrinkle and anti-skin aging effects.

Caffeic acid regulates LPS-induced NF-κB activation through NIK/IKK and c-Src/ERK signaling pathways in endothelial cells

The redox sensitive, proinflammatory nuclear transcription factor NF-κB plays a key role in inflammation. In a redox state disrupted by oxidative stress, pro-inflammatory genes are upregulated by the activation of NF-κB via diverse kinases. Thus, the search and characterization of new substances that modulate NF-κB are topics of considerable research interest. Caffeic acid is a component of garlic, some fruits, and coffee, and is widely used as a phenolic agent in beverages. In the present study, caffeic acid was examined with respect to the modulation of inflammatory NF-κB activation via the redox-related c-Src/ERK and NIK/IKK pathways via the reduction of oxidative stress. YPEN-1 cells (an endothelial cell line) were used to explore the molecular mechanism underlying the anti-inflammatory effect of caffeic acid by examining its modulation of NF-κB signaling pathway by LPS. Our results show that LPS-induced oxidative stress-related NF-κB activation upregulated pro-inflammatory COX-2, NF-κB targeting gene which were all inhibited effectively by caffeic acid. Our study shows that caffeic acid inhibits the activation of NF-κB via the c-Src/ERK and NIK/IKK signal transduction pathways. Our results indicate that antioxidative effect of caffeic acid and its restoration of redox balance are responsible for its anti-inflammatory action. Thus, the study provides new information regarding the anti-inflammatory properties of caffeic acid and the roles in the regulation of LPS-induced oxidative stress induces alterations in signal transduction pathways.

Anti-wrinkle and anti-inflammatory effects of active garlic components and the inhibition of MMPs via NF-κB signaling

Skin aging is a multisystem degenerative process caused by several factors, such as, UV irradiation, stress, and smoke. Furthermore, wrinkle formation is a striking feature of photoaging and is associated with oxidative stress and inflammatory response. In the present study, we investigated whether caffeic acid, S-allyl cysteine, and uracil, which were isolated from garlic, modulate UVB-induced wrinkle formation and effect the expression of matrix-metalloproteinase (MMP) and NF-κB signaling. The results obtained showed that all three compounds significantly inhibited the degradation of type І procollagen and the expressions of MMPs in vivo and attenuated the histological collagen fiber disorder and oxidative stress in vivo. Furthermore, caffeic acid and S-allyl cysteine were found to decrease oxidative stress and inflammation by modulating the activities of NF-κB and AP-1, and uracil exhibited an indirect anti-oxidant effect by suppressing cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) expressions levels and downregulating transcriptional factors. These results suggest that the anti-wrinkle effects of caffeic acid, S-allyl cysteine, and uracil are due to anti-oxidant and/or anti-inflammatory effects. Summarizing, caffeic acid, S-allyl cysteine, and uracil inhibited UVB-induced wrinkle formation by modulating MMP via NF-κB signaling.

Seizure susceptibility in immature brain due to lack of COX-2-induced PGF2α

The immature brain is prone to seizure; however, the mechanism underlying this vulnerability has not been clarified. Febrile seizure is common in young children, and the use of non-steroidal anti-inflammatory drugs for febrile seizure is not recommended. In previous studies, we established that prostaglandin (PG) F2α, a product of cyclooxygenase (COX), acts as an endogenous anticonvulsant in the adult mouse. Therefore, we assumed that COX-2 activity was involved with seizure susceptibility in early life. In the present study, immature mice (postnatal day 9) were far more prone to kainic acid (KA)-induced seizures than mature mice (after postnatal day 35). Seizure activity began later in immature mice, but was more severe and was unaffected by a potent COX inhibitor, indomethacin; in contrast, indomethacin aggravated seizure activity in mature mice. Immature mouse brains exhibited little basal COX-2 expression and little KA-induced COX-2 induction, while KA-induced COX-2 expression and PGF2α release were prominent in mature brains. During brain development, COX expression was increased and glycosylated in an age-dependent manner, which was necessary for COX enzyme activity. Intracisternal PGF2α administration also reduced KA-induced seizure activity and mortality. Taken together, low COX activity and the resulting deficiency of PGF2α may be an essential cause of increased seizure susceptibility in the immature brain.

Ginsenoside Rc modulates Akt/FoxO1 pathways and suppresses oxidative stress

Ginsenoside Rc (Rc), a protopanaxadiol type ginsenoside, is the active component mainly responsible for the therapeutic and pharmacologic properties of ginseng, which are derived from its suppression of superoxide-induced free radicals. Forkhead box O (FoxO1) regulates various genes involved in cellular metabolism related to cell death and response to oxidative stress, and Rc is known to prevent FoxO1 phosphorylation by activation of PI3K/Akt and subsequent inhibition of AMP-activated protein kinase (AMPK) in cells exposed to tert-butylhydroperoxide (t-BHP). In the current study, we attempted the mechanism of increased catalase expression by Rc through inhibition of FoxO1 activation resulting from t-BHP-induced production of reactive species (RS). We found that overexpression of catalase induced by Rc resulted in suppression of RS production in kidney human embryo kidney 293T cells (HEK293T) cells, and that oxidative stress induced activation of PI3K/Akt and inhibition of the AMPK pathway and FoxO1 phosphorylation, leading to down-regulation of catalase, a FoxO1-targeting gene. In addition, treatment of HEK293T cells with Rc resulted in cAMP-response element-binding protein (CREB)-binding protein (CBP) regulated FoxO1 acetylation. Our results suggest that Rc modulates FoxO1 phosphorylation through activation of PI3K/Akt and inhibition of AMPK and FoxO1 acetylation through interaction with CBP and SIRT1, and that this leads to upregulation of catalase under conditions of oxidative stress.

Suppressed circulating bicyclo-PGE2 levels and leukocyte COX-2 transcripts in children co-infected with P. falciparum malaria and HIV-1 or bacteremia

In holoendemic Plasmodium falciparum transmission regions, malarial anemia is a leading cause of childhood morbidity and mortality. Identifying biomarkers of malaria disease severity is important for identifying at-risk groups and for improved understanding of the molecular pathways that influence clinical outcomes. We have previously shown that decreased cyclooxygenase (COX)-2-derived prostaglandin E2 (PGE2) levels are associated with enhanced clinical severity in cerebral malaria, malarial anemia, and malaria during pregnancy. Since children with malaria often have increased incidence of additional infections, such as bacteremia and HIV-1, we extend our previous findings by investigating COX-2 and PGE2 in children with falciparum malaria and co-infection with either bacteremia or HIV-1. Plasma bicyclo-PGE2/creatinine levels and peripheral blood COX-2 transcripts were significantly reduced in co-infected children relative to those with malaria mono-infection. Furthermore, suppression of circulating bicyclo-PGE2 was significantly associated with reduced hemoglobin levels in both mono- and co-infected children with malaria, suggesting that bicyclo-PGE2 may represent both a marker and mediator of malaria pathogenesis.

The effect of lipopolysaccharide on enhanced inflammatory process with age: Modulation of NF-κB

Oxidative stress is thought to be a causative factor for age-related damage in a wide variety of cellular constituents that can lead to dysfunction and various pathological conditions, including the inflammatory process. At the molecular level, the redox-sensitive transcription factor, NF-κB plays a key role in the regulation of the inflammatory process, along with cytokines, cyclooxygenase-2 (COX-2), and inducible nitric oxide synthase (iNOS). We studied the mechanism underlying the modulation of the inflammatory reaction with age by investigating NF-κB activation and the expression of COX-2, iNOS, and cytokines genes in hepatic tissues isolated from young and old rats. We expanded our investigation of these factors in rats injected with the inflammatory activator, lipopolysaccharide (LPS). Data showed that NF-κB activity was up-regulated with age and was further enhanced by LPS injection, indicating an increased susceptibility and sensitivity to the inflammatory stimulus with age. To explore further the molecular events leading to NF-κB activation, we investigated the inhibitory component of NF-κB complex, IκB. Cytosolic IκBα, but not IκBβ, was significantly decreased in both old and LPS-treated rats, signifying the enhanced migration of cytosolic NF-κB complex into the nucleus following dissociation from the inhibitor. The appearance of the polypeptide, p65, as determined in the nucleus, corresponded with the change in IκBα, providing further supporting evidence for the molecular process involved in NF-κB activation. Our additional investigation of two proinflammatory-related enzymes, COX-2 and iNOS, and three cytokines, interleukin-1β (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor-α, clearly showed aged-related increases, in corroboration with the NF-κB activation. Our results demonstrated that LPS injection caused the enhanced gene expression of inducible proinflammatory proteins, COX-2 and iNOS through NF-κB activation.

Calorie restriction modulates redox-sensitive AP-1 during the aging process

Oxidative stress is claimed to be a major cause of aging. Recent data suggest that calorie restriction (CR) prolongs life span by its ability to retard aging, possibly by regulating the intracellular redox status through its antioxidative actions. Currently, there is little information showing the influences of age and CR on the redox-sensitive transcription factor activator protein-1 (AP-1). In the present study, we investigated how age affects the status of AP-1 and whether CR modulates the age effect. For our study, we used the kidney from male Fischer 344 rats, ages 6, 12, 18, and 24 months fed ad libitum (AL) or a CR diet. Results from our study showed that AP-1 binding activity markedly increases with age, while CR keeps this activity at the level of 6-month-old rats. We found that c-Jun and c-Fos protein levels increase during aging, and that aging induces phosphorylation of c-Jun, which might enhance AP-1 transcriptional activity. For CR's action, we found that in the nucleus of aged rats, AP-1 activation was blunted by decreasing c-Jun and c-Fos levels and inhibiting c-Jun protein phosphorylation. Results also indicated that matrix metalloproteinase-13 and heme oxygenase-1, which have an AP-1 binding site in their promoter regions, have a similar tendency toward AP-1 binding activity. Based on the data of these findings, we concluded that AP-1 activity increases in rat kidney with age and that CR reduces AP-1 activity.

New analogues of 13-hydroxyocatdecadienoic acid and 12-hydroxyeicosatetraenoic acid block human blood platelet aggregation and cyclooxygenase-1 activity

Background

Thromboxane A₂ is derived from arachidonic acid through the action of cyclooxygenases and thromboxane synthase. It is mainly formed in blood platelets upon activation and plays an important role in aggregation. Aspirin is effective in reducing the incidence of complications following acute coronary syndrome and stroke. The anti-thrombotic effect of aspirin is obtained through the irreversible inhibition of cyclooxygenases. Analogues of 12-hydroxyeicosatetraenoic acid and 13-hydroxyocatdecadienoic acid were shown previously to modulate platelet activation and to block thromboxane receptors.

Results and discussion

We synthesized 10 compounds based on the structures of analogues of 12-hydroxyeicosatetraenoic acid and 13-hydroxyocatdecadienoic acid and evaluated their effect on platelet aggregation triggered by arachidonic acid. The structure activity relationship was evaluated. Five compounds showed a significant inhibition of platelet aggregation and highlighted the importance of the lipidic hydrophobic hydrocarbon chain and the phenol group. Their IC₅₀ ranged from 7.5 ± 0.8 to 14.2 ± 5.7 μM (Mean ± S.E.M.). All five compounds decreased platelet aggregation and thromboxane synthesis in response to collagen whereas no modification of platelet aggregation in response to thromboxane receptor agonist, U46619, was observed. Using COS-7 cells overexpressing human cyclooxygenase-1, we showed that these compounds are specific inhibitors of cyclooxygenase-1 with IC₅₀ ranging from 1.3 to 12 μM. Docking observation of human recombinant cyclooxygenase-1 supported a role of the phenol group in the fitting of cyclooxygenase-1, most likely related to hydrogen bonding with the Tyr 355 of cyclooxygenase-1.

Conclusions

In conclusion, the compounds we synthesized at first based on the structures of analogues of 12 lipoxygenase metabolites showed a role of the phenol group in the anti-platelet and anti-cyclooxygenase-1 activities. These compounds mediate their effects via blockade of cyclooxygenase-1.

Reduced systemic bicyclo-prostaglandin-E2 and cyclooxygenase-2 gene expression are associated with inefficient erythropoiesis and enhanced uptake of monocytic hemozoin in children with severe malarial anemia

In holoendemic Plasmodium falciparum transmission areas, severe malaria primarily occurs in children aged <48 months and manifests as severe malarial anemia [SMA; hemoglobin (Hb) < 6.0 g/dL]. Induction of high levels of prostaglandin-E(2) (PGE(2)) through inducible cyclooxygenase-2 (COX-2) is an important host-defense mechanism against invading pathogens. We have previously shown that COX-2-derived PGE(2) levels are reduced in children residing in hyperendemic transmission regions with cerebral malaria and in those with mixed sequelae of anemia and hyperparasitemia. Our in vitro studies further demonstrated that reduced PGE(2) was due to downregulation of COX-2 gene products following phagocytosis of malarial pigment (hemozoin, PfHz). However, as COX-2-PGE(2) pathways and the impact of naturally acquired PfHz on erythropoietic responses have not been determined in children with SMA, plasma and urinary bicyclo-PGE(2)/creatinine and leukocytic COX-2 transcripts were determined in parasitized children (<36 months) stratified into SMA (n = 36) and non-SMA (Hb ≥ 6.0 g/dL; n = 38). Children with SMA had significantly reduced plasma (P = 0.001) and urinary (P < 0.001) bicyclo-PGE(2)/creatinine and COX-2 transcripts (P = 0.007). There was a significant positive association between Hb and both plasma (r = 0.363, P = 0.002) and urinary (r = 0.500, P = 0.001)] bicyclo-PGE(2)/creatinine. Furthermore, decreased systemic bicyclo-PGE(2)/creatinine was associated with inefficient erythropoiesis (i.e., reticulocyte production index; RPI < 2.0, P = 0.026). Additional analyses demonstrated that plasma (P = 0.031) and urinary (P = 0.070) bicyclo-PGE(2)/creatinine and COX-2 transcripts (P = 0.026) progressively declined with increasing concentrations of naturally acquired PfHz by monocytes. Results presented here support a model in which reduced COX-2-derived PGE(2), driven in part by naturally acquired PfHz by monocytes, promotes decreased erythropoietic responses in children with SMA.

Acid-induced COX-2 expression and prostaglandin E2 production via activation of ERK1/2 and p38 MAPK in cultured feline esophageal smooth muscle cells

Cyclooxygenase (COX)-2 is known to play an important role in inflammatory conditions such as reflux esophagitis resulting from acid reflux. In this study, we tested whether an acidic medium (pH 4.0) induces an increase in COX-2 expression or PGE(2) production, and explored the implication of mitogen-activated protein kinases (MAPKs) activation in these responses in cultured cat esophageal smooth muscle cells. Acidic cytotoxicity was assessed and expression changes in COXs or phosphorylated MAPKs were analyzed by Western blotting. PGE(2) production was measured by immunoassay. No significant decrease in cell viability was observed for 6 h exposure to acidic medium. COX-2 expression and PGE(2) production significantly increased to maximal levels at 6 h exposure to acidic medium. The cells also exhibited significant activation of ERK1/2 and p38 MAPK, but not JNK within 10 min under acidic medium. The increments of COX-2 expression and PGE(2) production by acidic medium were decreased by pretreatment with PD98059 or SB202190, respectively. These results suggest that acidic environments may enhance the COX-2 expression and PGE(2) production through activation of ERK1/2 and p38 MAPK in the cultured cat esophageal smooth muscle cells.

The effects of reactive hyperemia on stimulation of endothelium-derived nitric oxide in on-pump and off-pump coronary artery bypass surgeries

The purpose of this study is to compare the effects of cardiopulmonary bypass (CPB) on the endothelium-derived nitric oxide (NO) levels in on-pump and off-pump coronary artery bypass surgeries. Forty consecutive patients were divided randomly into two groups depending on use of CPB in coronary artery bypass graft surgery (group 1: n = 20, off-pump, and group 2: n = 20, on-pump). The plasma endothelium-derived NO levels were determined at baseline and after reactive hyperemia before and after surgery. Reactive hyperemia was induced by inflating a blood pressure cuff placed on the upper forearm, for 5 min at 250 mm Hg followed by a rapid deflation. Blood was collected at 1 min after cuff deflation from the radial artery on the same side. Preoperative use of all medications was recorded. The baseline plasma NO levels before operation were 17.10 ± 7.58 in group 1 and 15.49 ± 5.26 nmol/L in group 2. Before operation after reactive hyperemia, the plasma NO levels were 26.97 ± 11.49 in group 1 and 26.57 ± 12.87 nmol/L in group 2. Two hours after surgery, the plasma NO levels at baseline and after reactive hyperemia were not significantly different from each other (group 1: 18.03 ± 6.37 and group 2: 19.89 ± 9.83 nmol/L; group 1: 27.89 ± 18.36 and group 2: 39.13 ± 23.60 nmol/L, respectively; P > 0.05). A positive correlation was shown between preoperative nitroglycerine use and the postoperative plasma NO levels after reactive hyperemia (r = 0.51, P = 0.001). Linear regression analysis was performed (F = 4.10, R = 0.56, R(2)  = 0.32, P =  0.008) and the only independent parameter that had an effect on postoperative plasma NO levels after reactive hyperemia was found to be preoperative nitroglycerine use (t = 3.68, P = 0.001). Coronary artery bypass surgery with CPB does not have significant effect on plasma endothelial derived NO levels. The postoperative plasma NO levels after reactive hyperemia significantly correlated with preoperative nitroglycerine use.

High glucose increases expression of cyclooxygenase-2, increases oxidative stress and decreases the generation of nitric oxide in mouse microvessel endothelial cells

Hyperglycaemia is a key factor that contributes to the development of diabetes-related microvascular disease. Both cyclooxygenase I and cyclooxygenase II are expressed in endothelial cells and play key roles in the regulation of cardiovascular function. In the current study we tested the hypothesis that hyperglycaemia-induced increased expression of cyclooxygenase II is a contributing factor both to the increased oxidative stress and to the reduction in the generation of nitric oxide in microvessel endothelial cells following their exposure to high glucose. We demonstrated that the exposure of mouse microvascular endothelial cells to high glucose for 3 days decreased the generation of nitric oxide and enhanced production of superoxide. Western blots illustrated that exposure to high glucose also increased endothelial nitric oxide synthase and cyclooxygenase II protein expression levels and decreased the dimer/monomer ratio of endothelial nitric oxide synthase protein. All the changes induced by the high glucose culture media could be reversed by either the cyclooxygenase II inhibitor CAY10404, the non-selective cyclooxygenase inhibitor indomethacin or the protein kinase C inhibitor chelerythrine, but not solely by preincubation with the antioxidant and putative NADPH oxidase inhibitor, apocynin. Our data indicate that high glucose induced oxidative stress is linked to an increase in the expression of cyclooxygenase II and a reduced generation of nitric oxide that is associated with an uncoupled endothelial nitric oxide synthase, possibly due to decreased dimer/monomer ratio.

Anti-inflammatory effects of intravenously administered lidocaine hydrochloride on ischemia-injured jejunum in horses

OBJECTIVE

To investigate effects of lidocaine hydrochloride administered IV on mucosal inflammation in ischemia-injured jejunum of horses treated with flunixin meglumine.

ANIMALS

24 horses.

PROCEDURES

Horses received saline (0.9% NaCl) solution (SS; 1 mL/50 kg, IV [1 dose]), flunixin meglumine (1 mg/kg, IV, q 12 h), lidocaine (bolus [1.3 mg/kg] and constant rate infusion [0.05 mg/kg/min], IV, during and after recovery from surgery), or both flunixin and lidocaine (n = 6/group). During surgery, blood flow was occluded for 2 hours in 2 sections of jejunum in each horse. Uninjured and ischemia-injured jejunal specimens were collected after the ischemic period and after euthanasia 18 hours later for histologic assessment and determination of cyclooxygenase (COX) expression (via western blot procedures). Plasma samples collected prior to (baseline) and 8 hours after the ischemic period were analyzed for prostanoid concentrations.

RESULTS

Immediately after the ischemic period, COX-2 expression in horses treated with lidocaine alone was significantly less than expression in horses treated with SS or flunixin alone. Eighteen hours after the ischemic period, mucosal neutrophil counts in horses treated with flunixin alone were significantly higher than counts in other treatment groups. Compared with baseline plasma concentrations, postischemia prostaglandin E(2) metabolite and thromboxane B(2) concentrations increased in horses treated with SS and in horses treated with SS or lidocaine alone, respectively.

CONCLUSIONS AND CLINICAL RELEVANCE

In horses with ischemia-injured jejunum, lidocaine administered IV reduced plasma prostaglandin E(2) metabolite concentration and mucosal COX-2 expression. Coadministration of lidocaine with flunixin ameliorated the flunixin-induced increase in mucosal neutrophil counts.

Activation mechanisms of endothelial NF-κB, IKK, and MAP kinase bytert-butyl hydroperoxide

Lipid peroxidation plays a major role in vascular dysfunction and age-related cardiovascular diseases. A major product of lipid peroxidation, tert-butyl hydroperoxide (t-BHP), has been reported to modulate vascular reactivity and cellular signaling. To better understand vascular abnormality, we set out to delineate the activation mechanism of nuclear factor kappa B (NF-kappaB) by t-BHP and the regulation of MAPK in endothelial cells. The results showed that t-BHP induces NF-kappaB activation by an inhibitor of kappaB (IkappaB) phosphorylation through IkappaB kinase (IKK) activation. Our data from this t-BHP study also showed increased p38 MAP kinase and ERK activity; however, interestingly, t-BHP showed no influence on JNK. Pretreatment with the p38 MAP kinase inhibitor, SB203580 and the ERK1/2 inhibitor, PD98059, prevented t-BHP-induced increases in p65 translocation, NF-kappaB luciferase activity, and phospho-IKKalpha/beta. Data suggested that t-BHP induces NF-kappaB activation through the IKK pathway, which involves p38 MAPK and ERK activation. This study illustrates a role of t-BHP in NF-kappaB activation and MAPK related-signaling pathways. The t-BHP-induced activation of NF-kappaB and MAPK could be a major player in vascular dysfunctions, as seen in oxidative stressed responses and the vascular inflammatory process.

Critical role of COX-1 in prostacyclin production by human endothelial cells under modification of hydroperoxide tone

We aimed at evaluating the relative contribution of cyclooxygenase (COX) -1 and COX-2 to the synthesis of prostacyclin in endothelial cells under static conditions in the presence or absence of exogenous arachidonic acid and/or altered intracellular redox balance. Selective inhibitors of either COX-1 (SC560 and FR122047) or COX-2 (SC236) concentration dependently (1-300 nM) reduced basal and interleukin (IL) -1beta-induced prostacyclin production in human umbilical vein endothelial cells by 70% or more; compound selectivity was confirmed using a whole-blood assay (IC(50) COX-1/COX-2: 13 nM/930 nM for SC-560; 9 microM/457 nM for SC-236). The observed concomitant formation of isoprostane appeared to be associated with COX enzyme activity, while formation of COX-1/COX-2 heterodimers was detected by immunoprecipitation. In the presence of arachidonic acid and 12-hydroperoxy-eicosatetraenoic acid, either exogenous or provided by platelet activation, or after glutathione depletion, COX-1 inhibition but not COX-2 inhibition concentration dependently decreased prostacyclin production. Both isoforms appear to contribute to basal prostacyclin production by endothelial cells, with COX-2 providing the hydroperoxide tone required for COX-1 activity. Conversely, in the case of intracellular glutathione depletion or enhanced availability of arachidonic acid and hydroperoxides, selective COX-2 inhibition did not significantly affect the production of endothelial prostacyclin. These findings contribute to a better understanding of the effects of cyclooxygenase inhibitors on prostacyclin production.

Arsenic trioxide inhibits ATRA-induced prostaglandin E2 and cyclooxygenase-1 in NB4 cells, a model of acute promyelocytic leukemia

In acute promyelocytic leukemia (APL), all-trans retinoic acid (ATRA) triggers cell differentiation, while arsenic trioxide (As(2)O(3)) generates partial differentiation and apoptosis. Animal and human studies suggest that newly diagnosed APL patients can be cured using As(2)O(3) combined with ATRA. Cyclooxygenases are involved in prostaglandins and thromboxane synthesis. We have recently demonstrated that ATRA induces cyclooxygenase-1 (COX-1) expression and prostaglandin synthesis in NB4 cells and in blasts from patients with APL. In the present study we investigated the effect of ATRA and As(2)O(3) co-treatment on COX-1 expression and prostaglandin formation and tested the effect of the COX-1/COX-2 nonselective inhibitor indomethacin on cell differentiation. Arsenic treatment of NB4 cells resulted in a partial but significant reduction of ATRA-dependent induction of COX-1 expression and activity. Pretreatment of NB4 cells with indomethacin significantly impaired ATRA/As(2)O(3)-induced differentiation, as assessed by cell morphology, nitroblue tetrazolium test or CD11c expression. PGE(2) reversed the negative effect of indomethacin on differentiation of ATRA/As(2)O(3)-treated NB4 cells. In conclusion, COX-1 contributes to ATRA-dependent maturation of NB4 cells and is affected by As(2)O(3). These results also suggest that nonsteroidal antiinflammatory drugs should be avoided in APL patients treated with the combination of ATRA and As(2)O(3).

Impact of off-pump coronary artery bypass surgery on systemic inflammation: current best available evidence

The systemic inflammatory response after coronary artery bypass grafting using cardiopulmonary bypass (CPB) contributes substantially to postoperative organ dysfunction and coagulation disorders. Important features of this inflammatory reaction include the activation of complement and leukocytes, the release of proinflammatory cytokines, alterations in the metabolism of nitric oxide, and an increase in the production of oxygen-free radicals, which in some cases may lead to oxidant stress injury. Several strategies including the use of steroids, use of aprotinin, heparin-coated CPB circuits, and hemofiltration have been reported to reduce the inflammatory reaction induced by CPB and its consequences. A more radical and effective way of counteracting the effects of the inflammatory reaction and oxidative stress may be the omission of CPB itself. The development and application of off-pump coronary artery bypass (OPCAB) technology has largely been driven by this theme of avoiding systemic inflammatory reaction to decrease the incidence and/or severity of adverse outcomes. This review article discusses the influence of cardiopulmonary bypass on systemic inflammation and attempts to evaluate the current best available evidence on the impact of OPCAB on systemic inflammation.

The activation of NF-kappaB through Akt-induced FOXO1 phosphorylation during aging and its modulation by calorie restriction

Insulin-induced PI3K/Akt activation is known to inhibit a family of Forkhead transcription factors (FOXO), which can lead to increased oxidative stress in several model organisms. One of major transcription factors activated by oxidative stress and responsible for the production of many proinflammatory cytokines is NF-kappaB. In the present study, We were carried out to determine the relationship between FOXO1 and NF-kappaB activation using HEK293T cells and aged kidney isolated from ad libitum fed (AL) and 40% calorie restriction (CR) rats. Results showed that phosphorylation of FOXO1 and NF-kappaB activation were significantly increased in old rats. Moreover, FOXO1 phosphorylation and NF-kappaB activation were shown to be significantly lower in the CR rats compared with 24-month-old AL rats. To further explore the molecular link between FOXO and NF-kappaB, we performed transfection experiments with FOXO-mutant plasmid in cultured HEK293T cells. Treatment of the cell with insulin led to NF-kappaB activation through the phosphorylation of FOXO via the PI3K/Akt pathway. These results indicate that insulin promoted NF-kappaB activation through phosphorylation of FOXO1 by upregulating PI3K/Akt signaling. We conclude that the phosphorylation of FOXO1 regulates NF-kappaB nuclear translocation by activating PI3K/Akt during aging, which was suppressed by the hypoinsulinemic action of CR.

Regulation of the prostaglandin enzymatic system by estradiol and progesterone in nonpregnant sheep cervix

In the present study, we examined the in vivo effects of estradiol (E(2)) and progesterone on cyclooxygenase (COX) 2, prostaglandin F synthase (PTGFS, also known as PGFS), and membrane-associated prostaglandin E synthase 1 (mPTGES1) expression at both mRNA and protein levels using a nonpregnant ovariectomized (OVX) sheep model. Sixteen ewes were OVX shortly after ovulation. After 40 days, ewes were treated with saline (Cont, n=5), or E(2) infused intravenously for 2 days (50 microg/day, n=5) or intravaginal progesterone (P) sponges for 10 days (0.3 g P, n=6). Cervical COX2, PTGFS, and mPTGES1 mRNA and protein were quantified by northern and western blot analyses respectively. In situ hybridization and/or immunocytochemistry were used to localize the cellular distribution of COX2, PTGFS, and mPTGES1 mRNAs and proteins. COX2 mRNA abundance increased significantly in the cervix after E(2) treatment (P<0.05). However, progesterone was a more potent stimulator than E(2) of COX2 mRNA and protein abundance in the cervix (P<0.01). In contrast, PTGFS and mPTGES1 mRNA and protein concentrations did not change after E(2) or progesterone treatment (P>0.05). COX2, PTGFS, and mPTGES1 mRNA and protein were only localized in cervical glandular epithelial cells. This study shows that increased cervical COX2 mRNA and protein, but not PTGFS and mPTGES1 mRNA and protein, were associated with E(2) and progesterone treatment in nonpregnant sheep. More strikingly, progesterone was a more potent stimulator of cervical COX2 expression than E(2). The expression of COX2, PTGFS, and mPTGES1 mRNA and/or protein was confined in the cervical glandular epithelial cells of nonpregnant sheep.

Modulation of COX-2 expression by statins in human monocytic cells

Macrophage cyclooxygenase-2 (COX-2) plays an important role in prostaglandin E2 and thromboxane A2 production. Statins are inhibitors of HMG CoA (3-Hydroxy-3-methylglutaryl coenzyme A) reductases and cholesterol synthesis, which block the expression of several inflammatory proteins independent of their capacity to lower endogenous cholesterol. In the present study, we investigated the effect of simvastatin and mevastatin on COX-2 induction in human monocytic cell line U937 and analyzed the underlying mechanisms. Pretreatment of U937 cells with simvastatin or mevastatin for 24 h resulted in a significant reduction in the lipopolysaccharide (LPS)-dependent induction of prostaglandin E2, thromboxane A2 synthesis, and COX-2 expression. Mevalonate, the direct metabolite of HMG CoA reductase, and farnesyl pyrophosphate and geranylgeranyl-pyrophosphate, intermediates of the mevalonate pathway, significantly reversed the inhibitory effect of statins on COX-2. An inhibitor of geranylgeranyl transferases, GGTI-286 mimicked the effect of statins on COX-2 expression. Cytonecrotic factor-1 increased LPS-dependent expression of COX-2. Treatment of cells with NSC 23766, an inhibitor of Rac, which we demonstrated to block Rac 2 activation, resulted in an inhibition of the LPS-dependent expression of COX-2. Whereas no effect was obtained with RhoA/C blocker, C3 exoenzyme. Gel retardation experiments and NFkappaB-p65 transcription factor assay showed that simvastatin and NSC 23766 decrease significantly NF-kappaB complex formation. In macrophages, the antiinflammatory effects of statins are mediated in part through the inhibition of COX-2 and prostanoids. Rac GTPase protein is identified as one of the targets of statins in this regulation.

Suppression of age-related inflammatory NF-κB activation by cinnamaldehyde

Redox sensitive, pro-inflammatory nuclear transcription factor NF-kappaB plays a key role in both inflammation and aging processes. In a redox state disrupted by oxidative stress, pro-inflammatory genes are upregulated by the activation of NF-kappaB through diverse kinases. Thus, the search and characterization of new substances that modulate NF-kappaB are of recent research interest. Cinnamaldehyde (CNA) is the major component of cinnamon bark oil, which has been widely used as a flavoring agent in foodstuffs such as beverages and ice cream. In the present study, CNA was examined for its molecular modulation of inflammatory NF-kappaB activation via the redox-related NIK/IKK and MAPK pathways through the reduction of oxidative stress. Results show that age-related NF-kappaB activation upregulated NF-kappaB targeting genes, inflammatory iNOS, and COX-2, all of which were inhibited effectively by CNA. Our study further shows that CNA inhibited the activation of NF-kappaB via three signal transduction pathways, NIK/IKK, ERK, and p38 MAPK. Our results indicate that CNA's antioxidative effect and the restoration of redox balance were responsible for its anti-inflammatory action. Thus, the significance of the current study is the new information revealing the anti-inflammatory properties of CNA and the role it plays in the regulation of age-related alterations in signal transduction pathways.

Expression of COX-1 and COX-2 in a clinical model of acute inflammation

Cyclooxygenase (COX) plays an important role in the induction of pain and inflammation as well as the analgesic actions of NSAIDs and coxibs. This study evaluates the expression of the two isoforms COX-1 and COX-2 in a clinical model in which the surgical removal of impacted third molars is used to evaluate the analgesic activity of anti-inflammatory drugs. A 3-mm punch biopsy was performed on the oral mucosa overlying 1 impacted third molar immediately before extraction of 2 impacted lower third molars. After the second tooth was extracted, a second biopsy was performed adjacent to the surgical site either immediately after surgery or 30, 60, or 120 minutes after surgery. RNA was extracted from the biopsy specimens, and RT-PCR was performed to assess mRNA levels of COX-1, COX-2, and glyceraldehyde-3-phosphate dehydrogenase (G3PDH). The RT-PCR products in the biopsy specimens were normalized to G3PDH and compared with baseline. COX-2 mRNA was progressively increased at 30, 60, and 120 minutes after surgery (P<.05); COX-1 mRNA was transiently decreased at 60 minutes during the postsurgical period (P<.05). The results demonstrate peripheral elevation of COX-2 after tissue injury, which may contribute to increased prostaglandin E(2) at the site of injury, pain onset, and the analgesic activity of both nonselective NSAIDs and selective COX-2 inhibitors.

PERSPECTIVE

This clinical study uses a physiologically relevant model to determine the time course of expression of COX-1 and COX-2 in acute inflammation of the human oral mucosa. This study furthers our understanding of the contribution of the COX isoforms to acute pain.

Effects of melatonin on Candida sepsis in an experimental rat model

As an immunomodulator, melatonin reportedly exhibits protective effects in severe sepsis/shock induced by bacterial lipopolysaccharides in animal models. The present study was conducted to evaluate the possible protective effects of melatonin against experimental Candida sepsis in rats. A total of 40 adult male Wistar rats were randomly assigned to 4 groups: control, melatonin-treated control, septic, and melatonin-treated septic. Melatonin (200 microg/kg/d, intraperitoneally) injections were begun a week prior to sepsis induction and were continued daily for 3 wk until the end of the study. Cyclophosphamide was administered to animals in all groups as an immunosuppressive agent as a single dose 4 d prior to yeast inoculation. To cause sepsis, the Candida albicans (ATCC 10259) strain was administered intravenously. Amphotericin B was given as an antimycotic therapeutic agent as a single dose to septic rats. Plasma levels of interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-alpha), vascular cell adhesion molecule-1, and E-selectin were measured on the first and 15th days of sepsis. IL-6, TNF-alpha, vascular cell adhesion molecule-1, and E-selectin levels of septic rats were higher than those of controls. Melatonin reduced IL-6 levels and shortened time to improvement in animals with Candida sepsis. Levels of TNF-alpha and adhesion molecules in melatonin-treated septic rats were decreased compared with those in septic rats, but this difference was not statistically significant. In light of the current results, investigators conclude that melatonin may have therapeutic benefits in Candida sepsis and in classic antimycotic treatment because of its immune regulatory effects.

Interleukin-4 inhibits cyclo-oxygenase-2 expression and prostaglandin E production by human mature dendritic cells

Interleukin-4 (IL-4) is considered the key cytokine for inducing T helper type 2 (Th2) cell differentiation, while interferon-gamma and IL-12 are pivotal cytokines for Th1 immune responses. Paradoxically, IL-4 has also been demonstrated to enhance IL-12 production by dendritic cells, suggesting an IL-4-dependent regulatory feedback of the Th1/Th2 system. In addition, prostaglandin E(2) (PGE(2)), a lipid mediator of inflammation, has been implicated in the enhancement of Th2-type responses acting directly on T and B lymphocytes. PGE(2) synthesis is dependent on the serial engagement of various enzymes, among which the inducible cyclo-oxygenase-2 (COX-2) exerts a critical role in monocytes and dendritic cells. In this study we demonstrate that IL-4 inhibits COX-2 gene expression and consequently prevents secretion of PGE(2) by mature human dendritic cells. We also show that PGE(2) does not regulate IL-12 and IL-10 production by dendritic cells in an autocrine fashion. Hence, we suggest that IL-4 may exploit an IL-12-independent regulatory feedback of the Th1/Th2 system through PGE(2) inhibition.

Short-term feeding of baicalin inhibits age-associated NF-kappaB activation

Baicalin is a flavonoid isolated from Scutellaria baicalensis and is known to affect multiple biological functions, including the inhibition of aldose reductase, HIV infection, and nitric oxide producing activity. Oxidative stress is considered a major cause of aging and various age-related diseases, and among the key cellular components exquisitely sensitive to oxidative stress is the transcription factor, nuclear factor-kappaB (NF-kappaB). In the present study, we attempted to elucidate the mechanisms underlying the suppression of age-related NF-kappaB activation by baicalin in kidney tissue from old rats. Results showed NF-kappaB activation and the upregulation of NF-kappaB targeting genes, hemoxygenase-1, inducible nitric oxide synthase (iNOS), and COX-2 with age. In contrast, the increased expression of these NF-kappaB targeting genes was effectively inhibited by baicalin. Baicalin was shown to inhibit the NF-kappaB cascade via three signal transduction pathways, NIK/IKK, extracellular signal-regulated kinase (ERK), and p38 mitogen-activated protein kinase (MAPK). Our results clearly indicated the anti-oxidative effects of baicalin on age-related redox imbalance. Thus, the significance of the current study is the new information revealing the anti-oxidative properties of baicalin and the role it plays in the regulation of age-related alterations.