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)

Benzo[a]pyrene (BaP) is listed as a priority pollutant by the U.S. Environmental Protection Agency because it is one of the most potent carcinogens of all known polycyclic aromatic hydrocarbons (PAHs). The biodegradation of BaP is of interest as a means for mitigating its effects in polluted ecosystems. In the present study, BaP was oxidized with laccase from Trametes versicolor, which was immobilized on functionalized kaolinite particles, and the cytotoxicity and genotoxicity of BaP and its degradation intermediates were measured in human HaCaT keratinocytes and A3 T lymphocytes. Cytotoxicity was assessed by fluorescein diacetate (FDA) uptake, while the alkaline Comet assay measured genotoxicity, using tail moment, tail DNA content, and tail length as metrics for DNA damage. On the basis of first-order reaction kinetics, the half life (t(1/) (2)) for the oxidization of BaP by immobilized laccase was 58.5 hr. After 87 hr of oxidation, 20 muM of BaP had decreased to 9.6 muM. HPLC analysis identified 1,6-benzo[a]pyrene quinone (1,6-BaQ), 3,6-benzo[a]pyrene quinone (3,6-BaQ), and 6,12-benzo[a]pyrene quinone (6,12-BaQ) among the oxidation products. Most treatments of HaCaT cells and A3 lymphocytes with BaP or its quinone intermediates resulted in significant decreases in viability (P < 0.05); dose-dependent decreases in cell viability were detected at concentrations of 0.1, 1, and 5 muM, but none of these treatments resulted in decreases of >30%. While treatment of HaCaT cells with as little as 0.1 muM 6,12-BaQ caused significant DNA damage, DNA damage was detected in HaCaT cells only with 1 and 5 muM 1,6-BaQ and 3,6-BaQ, and 5 muM BaP. In Comet assays conducted with A3 lymphocytes, all three quinone intermediates caused significant increase in tail DNA content at 1 and 5 muM. The results indicate that immobilized laccase is capable of degrading BaP, but several of those biodegradation products produce significant levels of DNA damage in human cells.
Environ Mol Mutagen 2007 Mar
PMID:Biodegradation of benzo[a]pyrene with immobilized laccase: genotoxicity of the products in HaCat and A3 cells. 1725 27

The interactions of yttrium with N,N'-ethylenebis[2-(o-hydroxyphenolic)glycine] (EHPG) and N,N'-di(2-hydroxybenzyl)ethylenediamine-N,N'-diacetic acid (HBED) are investigated by using UV difference and fluorescence spectra methods in 0.1M N-2-hydroxyethylpiperazine-N-2-ethanesulfonic acid (Hepes) at pH 7.4. Yttrium binding produces two UV difference peaks near 240 and 294 nm, respectively, that both are the characteristic of phenolic groups binding to yttrium. The molar extinction coefficient of Y-EHPG and Y-HBED are (15.7 +/- 0.40) x 10(3), (15.8 +/- 0.80) x 10(3)cm(-1)M(-1) at 240 nm, respectively. Using EDTA as a competitor the obtained conditional equilibrium constants of the complexes are logK(Y-EHPG) = 15.07 +/- 0.32 and logK(Y-HBED) = 15.18 +/- 0.26, respectively. However, the effects of yttrium binding on the fluorescence intensity of EHPG and HBED are quite different, the former showing a decrease but the latter an increase.
Spectrochim Acta A Mol Biomol Spectrosc 2007 Sep
PMID:Spectral studies on the interaction of yttrium ion with the ligands of phenolic groups: N,N'-Ethylenebis[2-(o-hydroxyphenolic)glycine] and N,N'-di(2-hydroxybenzyl)ethylenediamine-N,N'-diacetic acid. 1726 67

Small cell lung cancer (SCLC) is a difficult disease to treat and sometimes has overexpression or mutation of c-Met receptor tyrosine kinase. The effects of c-Met/hepatocyte growth factor (c-Met/HGF, ligand for c-Met) on activation of reactive oxygen species (ROS) was determined. HGF stimulation of c-Met-overexpressing H69 SCLC cells (40 ng/ml, 15 min) resulted in an increase of ROS, measured with fluorescent probe 2'-7'-dichlorofluorescein diacetate (DCFH-DA) or dihydroethidine (DHE) but not in c-Met-null H446 cells. ROS was increased in juxtamembrane (JM)-mutated variants (R988C and T1010I) of c-Met compared with wild-type c-Met-expressing cells. ROS was significantly inhibited by preincubation of SCLC cells with pyrrolidine dithiocarbamate (PDTC, 100 microM) and/or SU11274 (small molecule c-Met tyrosine kinase inhibitor, 2 microM) for 3 h. PDTC and SU11274 also abrogated the HGF proliferative signal and cell motility in a cooperative fashion. H(2)O(2) treatment of SCLC cells (over 15 min) led to phosphorylation of c-Met receptor tyrosine kinase and further upregulated downstream phosphorylation of phospho-AKT, ERK1/2, and paxillin in a dose-dependent manner (125 microM to 500 microM). c-Met is an important target in lung cancer, and the pathways responsible for ROS generation together may provide novel therapeutic intervention.
Am J Physiol Lung Cell Mol Physiol 2007 Jun
PMID:Activation of HGF/c-Met pathway contributes to the reactive oxygen species generation and motility of small cell lung cancer cells. 1732 84

We investigated the nonlinear dynamics of the pressure vs. hydraulic conductivity (L(p)) relationship in lung microvascular endothelial cells and demonstrate that heparan sulfates, an important component of the endothelial glycocalyx, participate in pressure-sensitive mechanotransduction that results in barrier dysfunction. The pressure vs. L(p) relationship was complex, possessing both time- and pressure-dependent components. Pretreatment of lung capillary endothelial cells with heparanase III completely abolished the pressure-induced increase in L(p). This extends our (7) previous observation regarding heparan sulfates as mechanotransducers for shear stress. Inhibition of nitric oxide (NO) synthase with L-NAME (N(G)-nitro-L-arginine methyl ester HCl) and intracellular scavenging of reactive oxygen species (ROS) by TBAP [tetrakis-(4-benzoic acid) porphorin] significantly attenuated the pressure-induced L(p) response. Intracellular NO/ROS were visualized using the fluorescent dye, 2'7'-dichlorofluorescein diacetate (DCFA), and cells demonstrated a pressure-induced increase in intracellular fluorescence. Heparanase pretreatment significantly reduced the pressure-induced increase in intracellular fluorescence, suggesting that cell-surface heparan sulfates directly participate in mechanotransduction that results in NO/ROS production and increased permeability. This is the first report to demonstrate a role for heparan sulfates in pressure-mediated mechanotransduction and barrier regulation. These observations may have important clinical implications during conditions where pulmonary microvascular pressure is elevated.
Am J Physiol Lung Cell Mol Physiol 2007 Jun
PMID:Heparan sulfates mediate pressure-induced increase in lung endothelial hydraulic conductivity via nitric oxide/reactive oxygen species. 1735 Oct 62

Inhibitory effect of 1alpha,25dihydroxycholecalciferol (1,25D(3)=calcitriol) in different cell type is well recognized but its promoting effect on vascular smooth muscle cells (SMCs) is poor established. Therefore, the aim of this study was to determine stimulatory effect of calcitriol on aortal SMCs proliferation in culture. We used the cell division analysis procedure based on the quantitative sequential halving of the stably incorporating fluorescent dye carboxyfluorescein diacetate succinimidyl ester (CFSE). This technique allowed the visualization of cycles of SMCs division by flow cytometry. Rat aortal SMCs were labeled with CFSE and cultured for up to 10 days with defined concentration of calcitriol in medium. Proliferative activity as the percentage of SMCs in different phases of the cell cycle using propidium iodide was determined. Apoptosis was assessed using Annexin-V/CFDA method. The results suggest that low concentrations of an active form of vitamin D-1alpha,25dihydroxycholecalciferol applied in supraphysiological concentration of 10 nmol/l is a mitogenic factor for aortal SMCs. None of the applied concentrations of calcitriol caused apoptosis. The findings well support our morphological (LM) and ultrastructural (TEM and SEM) observations.
J Steroid Biochem Mol Biol 2007 Mar
PMID:Quantifying division of aortal smooth muscle cells in culture stimulated by 1,25(OH)2D3. 1736 83

It is known that several second messengers, such as Ca(2+) or cAMP, play important roles in the intracellular pathway of electrolyte secretion in tracheal submucosal gland. However, the participation of cGMP, and therefore nitric oxide (NO), is not well understood. To investigate the physiologic role of NO, we first examined whether tracheal glands can synthesize NO in response to acetylcholine (ACh), and then whether endogenous NO has some effects on the ACh-triggered ionic currents. From the experiments using the NO-specific fluorescent indicator 4,5-diaminofluorescein diacetate salt (DAF-2DA), we found that a physiologically relevant low dose of ACh (100 nM) stimulated the endogenous NO synthesis, and it was almost completely suppressed in the presence of the nonspecific NO synthase (NOS) inhibitor Nomega-Nitro-L-arginine Methyl Ester Hydrochloride (L-NAME) or the neuronal NOS (nNOS)-specific inhibitor 7-Nitroindazole (7-NI). Patch-clamp experiments revealed that both the NOS inhibitors (L-NAME or 7-NI) and cGK inhibitors (KT-5823 or Rp-8-Br-cGMP) partially decreased ionic currents induced by 30 nM of ACh, but not in the case of 300 nM of ACh. Our results indicate that NO can be synthesized through the activation of nNOS endogenously and has potentiating effects on the gland secretion, under a physiologically relevant ACh stimulation. When cells were stimulated by an inadequately potent dose of ACh, which caused an excess elevation in [Ca(2+)](i), the cells were desensitized. Therefore, due to NO, gland cells become more sensitive to calcium signaling and are able to maintain electrolyte secretion without desensitization.
Am J Respir Cell Mol Biol 2007 Sep
PMID:A potentiating effect of endogenous NO in the physiologic secretion from airway submucosal glands. 1746 93

We previously reported that hypoxia attenuates cGMP-dependent protein kinase (PKG)-mediated relaxation in pulmonary vessels (Am J Physiol Lung Cell Mol Physiol 279: L611-L618, 2003). To determine whether hypoxia-induced reactive oxygen and nitrogen species (ROS and RNS, respectively) may be involved in the downregulation of PKG-mediated relaxation, ovine fetal intrapulmonary veins were exposed to 4 h of normoxia or hypoxia, with or without scavengers of ROS [N-acetylcysteine (NAC)] or peroxynitrite (quercetin and Trolox) and preconstricted with endothelin-1. Hypoxia decreased the relaxation response to 8-bromo-cGMP, PKG protein expression, and kinase activity and increased tyrosine nitration in PKG. However, ROS and RNS scavengers prevented these changes. To determine whether increased PKG nitration diminishes PKG activity, pulmonary vein smooth muscle cells (PVSMC) were exposed to shorter-term (30 min) hypoxia, which increased PKG nitration and decreased PKG activity but did not alter PKG protein expression. Increased dihydro-2,7-dichlorofluorescein diacetate (DCFH(2)-DA) fluorescence in PVSMC after 4 h or 30 min of hypoxia was not observed in the presence of NAC, quercetin, or Trolox, suggesting increased ROS and RNS production. Increased PKG nitration and the associated decrease in PKG activity in PVSMC after 30 min of hypoxia were also reversed on reoxygenation. The consequences of PKG nitration were assessed by exposure of purified PKG-Ialpha to peroxynitrite, which caused increased 3-nitrotyrosine immunoreactivity and inhibition of kinase activity. Our data suggest that, after 30 min of hypoxia, reversible covalent modification of PKG by hypoxia-induced reactive species may be an important mechanism by which the relaxation response to cGMP is regulated. However, after 4 h of hypoxia, PKG nitration and decreased PKG expression are involved.
Am J Physiol Lung Cell Mol Physiol 2007 Oct
PMID:Regulation of cGMP-dependent protein kinase-mediated vasodilation by hypoxia-induced reactive species in ovine fetal pulmonary veins. 1761 49

The effect of phenolic compounds: phenol, 2,4-dichlorophenol (2,4-DCP), 2,4-dimethylphenol (2,4-DMP) and catechol on human erythrocytes was studied. The level of fluorescent label - 6-carboxy-2',7'-dichlorodihydrofluorescein diacetate (H(2)DCFDA) oxidation by phenolic compounds in erythrocytes as well as the carbonyl group content and hemoglobin denaturation were monitored. H(2)DCFDA has been utilized extensively as a marker for studies of oxidative stress at the cellular level. We noted that 2,4-DCP, 2,4-DMP and catechol induced an increase in the concentration- and time-dependent H(2)DCFDA oxidation. We also observed an increase in carbonyl group content and the changes in parameter T (denaturation of hemoglobin) in erythrocytes incubated with 2,4-DCP, catechol and 2,4-DMP. The highest level of H(2)DCFDA oxidation was provoked by 2,4-DCP. The biggest changes of proteins in erythrocytes measured as the carbonyl group content were induced by 2,4-DMP, but measured as parameter T they were induced by catechol. It was observed that phenol did not oxidize H(2)DCFDA up to the concentration of 2.5 mM after 3 h of incubation. Phenol did not affect the carbonyl group content but decreased parameter T (induced denaturation of hemoglobin). To sum up, the kind of the substituent in a phenolic ring determines the molecular mechanism of action of the individual compound and the capacity of reactive oxygen species generation and thus damages the specified structures in human erythrocytes.
Blood Cells Mol Dis
PMID:Comparison of the effect of phenol and its derivatives on protein and free radical formation in human erythrocytes (in vitro). 1765 93

The brains of Alzheimer's disease (AD) patients are characterized by large deposits of amyloid beta peptide (Abeta). Abeta is known to increase free radical production in nerve cells, leading to cell death that is characterized by lipid peroxidation, free radical formation, protein oxi-dation, and DNA/RNA oxidation. In this study, we selected an extract of Gardenia jasminoides by screening, and investigated its ameliorating effects on Abeta-induced oxidative stress using PC12 cells. The effects of the extract were evaluated using the 2,7 -dichlorofluorescein diacetate (DCF-DA) assay and the 3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) reduction assay. To find the active component, the ethanol extract was partitioned with hexane, chloroform, and ethyl acetate, respectively, and the active component was purified by silica-gel column chromatography and HPLC. The results suggested that Gardenia jasminoides extract can reduce the cytotoxicity of Abeta in PC 12 cells, possibly by reducing oxidative stress.
Mol Cells 2007 Aug 31
PMID:Ameliorating effect of Gardenia jasminoides extract on amyloid beta peptide-induced neuronal cell deficit. 1784 5

Tracking antigen-specific cytotoxic T lymphocyte (CTL) function in vivo can be difficult due to the need to monitor the presence and subsequent destruction of antigen-bearing target cells. In this report, we describe a simple method using the fluorescent dye 5- (and 6-) carboxyfluorescein diacetate succinimidyl ester (CFSE) to evaluate CD8+ T-cell effector function in vivo by flow cytometry. In this assay, peptide-pulsed and control target cells are labeled to different levels with CFSE and coadministered to animals that have been previously immunized or tolerized to the cognate antigen. Because naive antigen-specific CD8+ T cells cannot acquire effector function within the time frame of this assay, adoptively transferred nonimmunized animals are used as negative controls for in vivo CTL function. Target cells are syngeneic splenocytes pulsed with peptide antigen and control cells are unpulsed syngeneic splenocytes. The loss of antigen-specific target cells is indicative of cytotoxicity and immunity, whereas the lack of killing in the setting of antigen recognition is suggestive of tolerance.
Methods Mol Biol 2007
PMID:Tracing tolerance and immunity in vivo by CFSE-labeling of administered cells. 1787 6


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