Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The chemoattractant receptor-homologous molecule expressed on Th2 cells (CRTH2) receptor, a G protein-coupled receptor that mediates chemotaxis of inflammatory cells in response to prostaglandin D2 (PGD2), is hypothesized to play a role in Th2-mediated allergic disease. In addition to PGD2, CRTH2 can be activated by indomethacin, a nonselective cyclooxygenase inhibitor and widely used nonsteroidal anti-inflammatory drug (NSAID). To evaluate the structural features that confer CRTH2 binding selectivity, structure-activity relationship analysis of arylacetic acid class NSAIDs as CRTH2 receptor ligands was performed. Indomethacin, sulindac sulfide, and zomepirac displaced [3H]PGD2 binding at the mouse CRTH2 receptor (mCRTH2) with comparable affinity (Ki = 1.5 +/- 0.1, 2.5 +/- 0.4, and 3.3 +/- 0.3 microM, respectively). The indomethacin metabolite 5'-O-desmethyl indomethacin (5'-DMI) possessed binding affinity similar to indomethacin; however, elimination of the 2-methyl substituent on the indole ring resulted in a 10-fold decrease in binding affinity. No binding was detected for indole acetic acid and indole derivatives such as tryptophan, serotonin, and 5-hydroxy indole acetic acid, demonstrating the importance of the N-acyl moiety of indomethacin. Neutral derivatives of indomethacin also failed to bind to mCRTH2, suggesting that the negatively charged carboxylate moiety participates in a key ligand-receptor interaction. Despite similar binding affinities, NSAID-type mCRTH2 ligands exhibited variable potencies as mCRTH2 agonists. Sulindac sulfide and 5'-DMI inhibited intracellular cyclic AMP ([cAMP]i) generation and stimulated cell migration comparable with indomethacin. In contrast, zomepirac did not inhibit [cAMP]i generation or stimulate cell migration but weakly antagonized the effects of indomethacin on [cAMP]i. Together, these results reveal structural features of arylacetic acid NSAIDs that may be exploited for the development of selective CRTH2 ligands.
Mol Pharmacol 2005 Mar
PMID:Structural determinants of arylacetic acid nonsteroidal anti-inflammatory drugs necessary for binding and activation of the prostaglandin D2 receptor CRTH2. 1556 82

The first purpose of this study was to investigate the in vivo absorption, biliary secretion, and first-pass effect of fluvastatin following regional intestinal dosing in the rat. We also examined the membrane transport mechanisms and made in silico predictions of the relative importance of various intestinal regions to the human absorption of fluvastatin. Fluvastatin was administered intravenously (2, 10, and 20 micromol/kg) and into the duodenum (1.46, 2.92, 7.32, and 14.6 micromol/kg), jejunum (14.6 micromol/kg), ileum (1.46 and 14.6 mciromol/kg), and colon (1.46 and 14.6 micromol/kg) as a solution to conscious rats. In a separate group of rats, bile was collected after an i.v. dose of fluvastatin (2 micromol/kg). In the Caco-2 model the bidirectional transport of fluvastatin (16 microM) was investigated with and without various efflux inhibitors (verapamil, vinblastine, probenecid, and indomethacin, 160 microM). The human in vivo absorption of fluvastatin from an oral immediate release tablet and that from an oral extended release tablet (both 40 mg) were simulated in GastroPlus. Neither the dose nor the intestinal region influenced the bioavailability of fluvastatin significantly. The rate of absorption was, however, affected by both the dose and the site of administration; duodenum = jejunum > colon > ileum, and higher following the high dose. Increasing the i.v. dose from 2 to 20 micromol/kg decreased the clearance (26 +/- 3 to 12 +/- 1 mL/min/kg), the hepatic extraction (66 +/- 8 to 30 +/- 2%), and the volume of distribution (7.3 +/- 0.3 to 2.1 +/- 0.7 L/kg) for fluvastatin (p < 0.05). Neither bile cannulation nor bile sampling affected the pharmacokinetics. Fluvastatin was secreted into the bile, probably by active transport. The in vitro permeability for fluvastatin was high (>10 x 10(-6) cm/s). Indomethacin, but not the other inhibitors, affected the transport in both directions suggesting mrp2 to be involved. In silico, 93% of the dose was absorbed from the small intestine and 6% from the colon when given as an immediate release formulation. The corresponding values for an extended release formulation were 21% and 74%, respectively. In conclusion, fluvastatin exhibits dose-dependent pharmacokinetics in the rat. The rate of absorption (Cmax, Tmax, and Cmax/AUC(lqc)) from the intestinal tract is both region and dose-dependent in the rat. This may be due to the involvement of mrp2 in the intestine and/or in the liver. These absorption properties have to be considered in the development of an extended release formulation of fluvastatin.
Mol Pharm
PMID:Regional intestinal absorption and biliary excretion of fluvastatin in the rat: possible involvement of mrp2. 1602 4

To assess effects of Celecoxib, selective cyclo-oxygenase (COX)-2 inhibitor, on matrix synthesis by chondrocytes under mechanical stress in vitro. Chondrocytes from 7-day-old rat articular cartilage were cultured. Cyclic mechanical stress (0.5 Hz, 7% elongation) was loaded using a Flexercell strain unit in the presence of Celecoxib, Indomethacin, and Ketoprofen. Concentrations of chondroitin sulfate (CS) in culture media were measured by high-performance liquid chromatography. Nitric oxide (NO) formation was detected by measuring NO2-accumulation in culture supernatants during the Griess reaction, using sodium nitrite as a standard. Levels of mRNA for aggrecan (AGC), type II collagen (CII), COX-2, and membrane-associated prostaglandin E synthase-1 (mPGES-1) were measured using real time reverse transcriptase-polymerase chain reaction. Under mechanical stress, levels of AGC and CII mRNA were decreased, while COX-2 mRNA levels were increased. Of the three drugs tested, only Celecoxib prevented the decrease of AGC mRNA and inhibited the release of CS. In addition, Celecoxib suppresses the level of mPGES-1 mRNA. These findings show that excessive mechanical stress decreases synthesis of matrix components in chondrocytes through a NO-regulated pathway, and suggest that Celecoxib has a protective effect on matrix metabolism.
Int J Mol Med 2005 Dec
PMID:The influence of Celecoxib on matrix synthesis by chondrocytes under mechanical stress in vitro. 1627 90

Dichlorodihydrofluorescein (DCFH(2)) is a widely used probe for intracellular H(2)O(2). However, H(2)O(2) can oxidize DCFH(2) only in the presence of a catalyst, whose identity in cells has not been clearly defined. We compared the peroxidase activity of Cu,Zn-superoxide dismutase (CuZnSOD), cytochrome c, horseradish peroxidase (HRP), Cu(2+), and Fe(3+) under various condi-tions to identify an intracellular catalyst. Enormous increase by bicarbonate in the rate of DCFH(2) oxidation distinguished CuZnSOD from cytochrome c and HRP. Cyanide inhibited the reaction catalyzed by CuZnSOD but accelerated that by Cu(2+) and Fe(3+). Oxidation of DCFH(2) by H(2)O(2) in the presence of a cell lys-ate was also enhanced by bicarbonate and inhibited by cyanide. Confocal microscopy of H(2)O(2)-treated cells showed enhanced DCF fluorescence in the presence of bicarbonate and attenuated fluorescence for the cells pre-incubated with KCN. Moreover, DCF fluorescence was intensified in CuZnSOD-transfected HaCaT and RAW 264.7 cells. We propose that CuZnSOD is a potential intracellular catalyst for the H(2)O(2)-dependent oxidation of DCFH(2).
Mol Cells 2006 Feb 28
PMID:Cu,Zn-superoxide dismutase is an intracellular catalyst for the H(2)O(2)-dependent oxidation of dichlorodihydrofluorescein. 1651 60

Asymmetric dimethylarginine (ADMA), an endogenous inhibitor of nitric oxide synthase (NOS), is emerging as a key contributor for endothelial dysfunction and its effects on endothelium are not yet completely defined. The aim of this study was to investigate ADMA-induced apoptosis and its mechanisms in human umbilical vein endothelial cells (HUVECs). Apoptosis was evaluated by in situ terminal uridine nick end labeling (TUNEL) assay and DNA fragmentation analysis. Caspase-3 activity was measured using a colorimetric protease assay kit. Activations of mitogen-activated protein kinases (MAPKs) were characterized by Western blot and immunofluorescence. Intracellular oxidant production was measured using H(2)DCF-DA, an oxidant-sensitive fluorescent indicator. ADMA (3-30 microM) induced apoptosis of HUVECs in a dose- and time-dependent manner. Caspase-3 was activated during apoptosis and its specific inhibitor DEVD-CHO significantly attenuated ADMA-induced apoptosis. Phosphorylation of p38 MAPK was induced by ADMA, and p38 MAPK specific inhibitor SB203580 concentration-dependently prevented ADMA-induced caspase-3 activation and cell apoptosis. ADMA increased intracellular oxidant production, which was significantly suppressed by intracellular antioxidant PDTC, l-arginine or antisense endothelial NOS mRNA. They also markedly prevented ADMA-induced phosphorylation of p38 MAPK and cell apoptosis. In conclusion, our present results demonstrate that ADMA induces apoptosis of endothelial cell via elevation of intracellular oxidant production, which involves p38 MAPK/caspase-3-dependent signaling pathway.
J Mol Cell Cardiol 2006 Apr
PMID:Asymmetric dimethylarginine induces apoptosis via p38 MAPK/caspase-3-dependent signaling pathway in endothelial cells. 1651 11

Treatment of metastatic breast cancer with doxorubicin (Doxo) in combination with trastuzumab, an antibody targeting the ErbB2 receptor, results in an increased incidence of heart failure. Doxo therapy induces reactive oxygen species (ROS) and alterations of calcium homeostasis. Therefore, we hypothesized that neuregulin-1 beta (NRG), a ligand of the cardiac ErbB receptors, reduces Doxo-induced alterations of EC coupling by triggering antioxidant mechanisms. Adult rat ventricular cardiomyocytes (ARVM) were isolated and treated for 18-48 h. SERCA protein was analyzed by Western blot, EC coupling parameters by fura-2 and video edge detection, gene expression by RT-PCR, and ROS by DCF-fluorescence microscopy. At clinically relevant doses Doxo reduced cardiomyocytes contractility, SERCA protein and SR calcium content. NRG, similarly as the antioxidant N-acetylcystein (NAC), did not affect EC coupling alone, but protected against Doxo-induced damage. NRG and Doxo showed an opposite modulation of glutathione reductase gene expression. NRG, similarly as NAC, reduced peroxide- or Doxo-induced oxidative stress. Specific inhibitors showed, that the antioxidant action of NRG depended on signaling via the ErbB2 receptor and on the Akt- and not on the MAPK-pathway. Therefore, NRG attenuates Doxo-induced alterations of EC coupling and reduces oxidative stress in ARVM. Inhibition of the ErbB2/NRG signaling pathway by trastuzumab in patients concomitantly treated with Doxo might prevent beneficial effects of NRG in the myocardium.
J Mol Cell Cardiol 2006 Nov
PMID:Neuregulin-1 beta attenuates doxorubicin-induced alterations of excitation-contraction coupling and reduces oxidative stress in adult rat cardiomyocytes. 1700 95

The ischemic preconditioning biological phenomenon has been explored to identify putative pharmacologic agents to mimic this cytoprotective program against cellular ischemic injury. Diazoxide administration confers this cytoprotection, however, whether this is via direct activation of the putative mitochondrial K(ATP) (mK(ATP)) channel which was originally proposed has been questioned. Here, we present data supporting an alternate hypothesis evoking mitochondrial respiratory inhibition rather than mK(ATP) channel activation, as a mediating event in the diazoxide-activated cytoprotective program. Mitochondrial respiration and reactive oxygen species (ROS) production was measured in digitonin-permeabilized C2C12 myotubes, allowing for the modulation of mK(ATP) conductance by changing the potassium concentration of the medium (0-130 mM). Diazoxide dose-dependently attenuated succinate-supported respiration, an effect that was independent of mK(ATP) channel conductance. Similarly, 5-hydroxydecanoate (5-HD), a putative mK(ATP) channel blocker, released diazoxide-induced respiratory inhibition independently of potassium concentration. Since diazoxide-induced cytoprotection and respiratory inhibition are both integrally linked to ROS generation we repeated above experiments following ROS generation using DCF fluorescence. Cytoprotective doses of diazoxide increased ROS generation independently of potassium concentration and 5-HD inhibited ROS production under the same conditions. Collectively these data support the hypothesis that diazoxide-mediated cytoprotection is independent of the conductance of the mK(ATP) channel and rather implicate mitochondrial respiratory inhibition-triggered ROS signaling.
Mol Cell Biochem 2007 Jan
PMID:Diazoxide-induced respiratory inhibition - a putative mitochondrial K(ATP) channel independent mechanism of pharmacological preconditioning. 1713 44

We checked the hypothesis whether the non-classical estrogen receptor modulators genistein and raloxifene could affect platelet aggregation through their direct effect on vascular tissue by regulating the synthesis of vasoactive compounds. In rat aortic strips, 10nM genistein or 10nM raloxifene significantly increased nitric oxide synthesis, event prevented by ICI182780. Both agents exhibited an antiaggregatory action, dependent on the nitric oxide release from vascular tissue, since preincubation of aortic strips with L-NAME partially and completely suppressed the inhibition of platelet aggregation induced by genistein or raloxifene respectively. The phytoestrogen enhanced phospholipase A(2) and prostacyclin release into the incubation medium. Indomethacin reduced in half the inhibition of platelet aggregation elicited by genistein. Finally, genistein or raloxifene also inhibited platelet aggregation in aortic strips from ovariectomized rats. In conclusion, genistein and raloxifene exhibit an antiplatelet activity through their direct action on vascular tissue, in rats with or without ovarian activity.
Mol Cell Endocrinol 2007 Mar 15
PMID:Effect of genistein and raloxifene on vascular dependent platelet aggregation. 1730 49

This study was designed to investigate whether indomethacin and NGX6 synergistically inhibit the growth and invasiveness of human colon cancer cells (HT-29 and SW620) and to elucidate the molecular mechanism of their action. Cell proliferation was assessed by MTT assay. Cell apoptosis was assessed by acridine orange/ethidium bromide staining (AO-EB) and annexin-V-FITC/PI assay. Invasive behaviors of colorectal cancer cells were examined by cell adhesion, migration, and invasion assays. Gap junctional intercellular communication (GJIC) was assessed by the scrape-loading/dye transfer technique. The subcellular localization and expression of beta-catenin protein was examined by immunofluorescence staining and western blot analysis, respectively. Indomethacin and NGX6 had a synergistic effect on inhibiting proliferation and invasiveness of colon cancer HT-29 and SW620 cells, restoring GJIC of HT-29 and SW620, and suppressing translocation of beta-catenin from the nucleus and cytoplasm to the plasma membrane. However, they did not have synergistic effects on enhancing apoptosis and suppressing extracellular matrix adhesion of HT-29 and SW620 cells. Indomethacin and NGX6 inhibit the proliferation and invasiveness of HT-29 and SW620 colon cancer cells by attenuating the WNT/ss-catenin signaling pathway.
Mol Cell Biochem 2009 Oct
PMID:Synergistic effect of indomethacin and NGX6 on proliferation and invasion by human colorectal cancer cells through modulation of the Wnt/beta-catenin signaling pathway. 1935 43

Reactive oxygen species (ROS) present in cigarette smoke (CS) are thought to contribute to the development of COPD. Although CS-ROS can hardly enter airway epithelial cells, and certainly not the circulation, systemic levels of ROS have been found to be elevated in COPD patients. We hypothesize that lipophilic components present in CS can enter airway epithelial cells and increase intracellular ROS production by disturbing mitochondrial function. Different airway epithelial cells were exposed to CS extract (CSE), hexane-treated CSE (CSE without lipophilic components), gaseous-phase CS, and water-filtered CS (gaseous-phase CS without ROS). Mitochondrial membrane potential (Deltapsi(m)) and ATP levels were assessed using the bronchial epithelial cell line Beas-2b. ROS generation measured directly by DCF fluorescence and indirectly by measuring free thiol groups (-SH) upon exposure to CS was assessed using lung alveolar epithelial cells devoid of functional mitochondria (A549-rho0), with normal A549 cells serving as controls. In Beas-2b cells, CSE (4 h) caused a dose-dependent decrease in Deltapsi(m) and ATP levels, whereas hexane-treated CSE did not. DCF fluorescence in A549 cells increased in response to CSE, whereas this was not the case in A549-rho0 cells. Exposure of A549 cells to CS resulted in a rapid decrease in free -SH, whereas exposure to ROS-depleted CS only resulted in a delayed decrease. This delayed decrease was less pronounced in A549-rho0 cells. Lipophilic components in CS disturb mitochondrial function, which contributes to increased intracellular generation of ROS. Our results are of importance in understanding the systemic effects of smoking observed in patients with COPD.
Am J Physiol Lung Cell Mol Physiol 2009 Jul
PMID:Lipid-soluble components in cigarette smoke induce mitochondrial production of reactive oxygen species in lung epithelial cells. 1941 10


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