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1.
RSC Adv ; 13(49): 34637-34645, 2023 Nov 22.
Article in English | MEDLINE | ID: mdl-38024992

ABSTRACT

Water-reducible polyester resin (WRPE) for insulation varnish was prepared from waste polyethylene terephthalate (PET), glycerol (GL), and phthalic anhydride (PA) via depolymerization and condensation. PET was depolymerized via glycolysis at different molar ratios of PET/GL (PET repeating unit/GL molar ratios: 1.6, 1.3, and 1.0) with zinc acetate as a catalyst at 220-230 °C. The resulting glycolytic products (GPs) were reacted with PA at contents of 5, 7.5, 10, 12.5, and 15 wt%, based on the total weight. The prepared WRPEs were dissolved in phenol, neutralized with aqueous ammonia to pH = 7-7.5, and diluted in water. The WRPEs were cured with hexamethoxymethyl melamine resin (HMMM, WRPE : HMMM = 70 : 30, based on the dry mass) at 140 °C for 2 h. The formation of GPs, WRPE, and WRPE-HMMM was investigated using Fourier transformer infrared spectroscopy and proton nuclear magnetic resonance spectroscopy; the thermal properties were characterized using thermogravimetric analysis and differential scanning calorimetry. The electrical insulation strength and volume resistivity of the cured films with PA content were investigated. This strength and volume resistivity first increased with increasing PA content and then decreased above 10 wt%. The results show that WRPE with a PA content of 10 wt% exhibits optimal insulation properties.

2.
Nat Commun ; 13(1): 6581, 2022 11 02.
Article in English | MEDLINE | ID: mdl-36323693

ABSTRACT

Astrocytes are critical components of the neurovascular unit that support blood-brain barrier (BBB) function. Pathological transformation of astrocytes to reactive states can be protective or harmful to BBB function. Here, using a human induced pluripotent stem cell (iPSC)-derived BBB co-culture model, we show that tumor necrosis factor (TNF) transitions astrocytes to an inflammatory reactive state that causes BBB dysfunction through activation of STAT3 and increased expression of SERPINA3, which encodes alpha 1-antichymotrypsin (α1ACT). To contextualize these findings, we correlated astrocytic STAT3 activation to vascular inflammation in postmortem human tissue. Further, in murine brain organotypic cultures, astrocyte-specific silencing of Serpina3n reduced vascular inflammation after TNF challenge. Last, treatment with recombinant Serpina3n in both ex vivo explant cultures and in vivo was sufficient to induce BBB dysfunction-related molecular changes. Overall, our results define the TNF-STAT3-α1ACT signaling axis as a driver of an inflammatory reactive astrocyte signature that contributes to BBB dysfunction.


Subject(s)
Blood-Brain Barrier , Induced Pluripotent Stem Cells , Humans , Animals , Mice , Blood-Brain Barrier/metabolism , Astrocytes/metabolism , alpha 1-Antichymotrypsin/metabolism , Cells, Cultured , Induced Pluripotent Stem Cells/metabolism , Inflammation/pathology , Tumor Necrosis Factor-alpha/metabolism , STAT3 Transcription Factor/metabolism
3.
Elife ; 102021 12 20.
Article in English | MEDLINE | ID: mdl-34927581

ABSTRACT

How daily clocks in the brain are set by light to local environmental time and encode the seasons is not fully understood. The suprachiasmatic nucleus (SCN) is a central circadian clock in mammals that orchestrates physiology and behavior in tune with daily and seasonal light cycles. Here, we have found that optogenetically simulated light input to explanted mouse SCN changes the waveform of the molecular clockworks from sinusoids in free-running conditions to highly asymmetrical shapes with accelerated synthetic (rising) phases and extended degradative (falling) phases marking clock advances and delays at simulated dawn and dusk. Daily waveform changes arise under ex vivo entrainment to simulated winter and summer photoperiods, and to non-24 hr periods. Ex vivo SCN imaging further suggests that acute waveform shifts are greatest in the ventrolateral SCN, while period effects are greatest in the dorsomedial SCN. Thus, circadian entrainment is encoded by SCN clock gene waveform changes that arise from spatiotemporally distinct intrinsic responses within the SCN neural network.


Subject(s)
Circadian Clocks/radiation effects , Photoperiod , Suprachiasmatic Nucleus/physiology , Animals , Circadian Rhythm , Female , Male , Mice , Suprachiasmatic Nucleus/radiation effects
5.
Respir Med Case Rep ; 21: 27-29, 2017.
Article in English | MEDLINE | ID: mdl-28377877

ABSTRACT

We report a case of invasive pulmonary aspergillosis in a patient taking ibrutinib, a Bruton's tyrosine kinase inhibitor used to treat refractory chronic lymphocytic leukemia. We hypothesize that ibrutinib promoted this infection by suppressing innate immune responses against Aspergillus. Clinicians should be aware of potential Aspergillus infections in patients treated with this drug.

7.
J Med Food ; 19(10): 945-951, 2016 Oct.
Article in English | MEDLINE | ID: mdl-27689410

ABSTRACT

We have provided a protocol for establishing an atopic dermatitis (AD) in vitro model, and evaluated the effects of Costaria costata (CC) extracts on AD in an in vitro model using keratinocytes and splenocytes from AD-induced mice and mast cells. HaCaT cells were each treated with 200 µg/mL of CC water extract (CCW), CC 10% ethanol extract (CCE10%), and CC 70% ethanol extract (CCE70%), immediately followed by stimulation with 20 ng/mL tumor necrosis factor (TNF)-α, and 20 ng/mL interferon (IFN)-γ for inflammation. The splenocytes from AD-induced mice were each treated with 200 µg/mL of CCW, CCE10%, and CCE70%, followed by stimulation with 5 µg/mL ConA or lipopolysaccharide (LPS), to induce T cell or B-cell activation, and 5 µg/mL LPS and 50 ng/mL interleukin-4, to induce immunoglobulin (Ig) E production. We investigated the effects of CCW, CCE10%, and CCE70% on the production of histamine in PMA, and A23187-stimulated MC/9 cells. We found that treatments with CC extracts decreased the production of proinflammatory cytokines in TNF-α and IFN-γ-stimulated HaCaT cells, and the suppression of the imbalance of Th1/Th2 cytokines and IgE production on primary splenocytes. In addition, CC extracts resulted in a decrease in histamine release in the PMA and A23187-simulated MC/9 cells. According to our present results, we can conclude that CC extracts may be effective for the treatment of other allergy diseases, and AD, via the attenuation of allergic reactions.

8.
Food Funct ; 7(10): 4193-4201, 2016 Oct 12.
Article in English | MEDLINE | ID: mdl-27713958

ABSTRACT

We investigated the anti-obesity effects of the potential prebiotic, laminarin, on mice fed a high-fat diet. A metagenomics approach was applied to characterize the ecological and functional differences of gut microbiota among mice fed a normal diet (CTL), a high-fat diet (HFD), and a laminarin-supplemented high-fat diet (HFL). The HFL mice showed a slower weight gain than the HFD mice during the laminarin-feeding period, but the rate of weight gain increased after the termination of laminarin supplementation. Gut microbial community analysis showed clear differences between the CTL and HFD mice, whereas the HFL mice were between the two. A higher abundance of carbohydrate active enzymes was observed in the HFL mice compared to the HFD mice, with especially notable increases in glycoside hydrolase and polysaccharide lyases. A significant decrease in Firmicutes and an increase in the Bacteroidetes phylum, especially the genus Bacteroides, were observed during laminarin ingestion. Laminarin ingestion altered the gut microbiota at the species level, which was re-shifted after termination of laminarin ingestion. Therefore, supplementing laminarin could reduce the adverse effects of a high-fat diet by shifting the gut microbiota towards a higher energy metabolism. Thus, laminarin could be used to develop anti-obesity functional foods. Our results also suggest that laminarin would need to be consumed regularly in order to prevent or manage obesity.


Subject(s)
Dietary Fats/administration & dosage , Gastrointestinal Microbiome/drug effects , Glucans/pharmacology , Animals , Female , Glucans/administration & dosage , Mice , Mice, Inbred BALB C , Random Allocation , Weight Gain/drug effects
9.
PLoS One ; 8(8): e72981, 2013.
Article in English | MEDLINE | ID: mdl-23977375

ABSTRACT

Mutations in cystic fibrosis transmembrane conductance regulator (CFTR) protein cause cystic fibrosis, a disease characterized by exaggerated airway epithelial production of the neutrophil chemokine interleukin (IL)-8, which results in exuberant neutrophilic inflammation. Because activation of an epidermal growth factor receptor (EGFR) signaling cascade induces airway epithelial IL-8 production, we hypothesized that normal CFTR suppresses EGFR-dependent IL-8 production and that loss of CFTR at the surface exaggerates IL-8 production via activation of a pro-inflammatory EGFR cascade. We examined this hypothesis in human airway epithelial (NCI-H292) cells and in normal human bronchial epithelial (NHBE) cells containing normal CFTR treated with a CFTR-selective inhibitor (CFTR-172), and in human airway epithelial (IB3) cells containing mutant CFTR versus isogenic (C38) cells containing wild-type CFTR. In NCI-H292 cells, CFTR-172 induced IL-8 production EGFR-dependently. Pretreatment with an EGFR neutralizing antibody or the metalloprotease TACE inhibitor TAPI-1, or TACE siRNA knockdown prevented CFTR-172-induced EGFR phosphorylation (EGFR-P) and IL-8 production, implicating TACE-dependent EGFR pro-ligand cleavage in these responses. Pretreatment with neutralizing antibodies to IL-1R or to IL-1alpha, but not to IL-1beta, markedly suppressed CFTR-172-induced EGFR-P and IL-8 production, suggesting that binding of IL-1alpha to IL-1R stimulates a TACE-EGFR-IL-8 cascade. Similarly, in NHBE cells, CFTR-172 increased IL-8 production EGFR-, TACE-, and IL-1alpha/IL-1R-dependently. In IB3 cells, constitutive IL-8 production was markedly increased compared to C38 cells. EGFR-P was increased in IB3 cells compared to C38 cells, and exaggerated IL-8 production in the IB3 cells was EGFR-dependent. Activation of TACE and binding of IL-1alpha to IL-1R contributed to EGFR-P and IL-8 production in IB3 cells but not in C38 cells. Thus, we conclude that normal CFTR suppresses airway epithelial IL-8 production that occurs via a stimulatory EGFR cascade, and that loss of normal CFTR activity exaggerates IL-8 production via activation of a pro-inflammatory EGFR cascade.


Subject(s)
Bronchi/pathology , Chemokines/biosynthesis , Cystic Fibrosis Transmembrane Conductance Regulator/metabolism , Epithelial Cells/metabolism , ErbB Receptors/metabolism , Inflammation Mediators/metabolism , ADAM Proteins/metabolism , ADAM17 Protein , Benzoates/pharmacology , Cell Line , Epithelial Cells/drug effects , Humans , Interleukin-1alpha/metabolism , Interleukin-8/biosynthesis , Models, Biological , Mutant Proteins/metabolism , Phosphorylation/drug effects , Receptors, Interleukin-1/metabolism , Thiazolidines/pharmacology
10.
Exp Cell Res ; 317(18): 2650-60, 2011 Nov 01.
Article in English | MEDLINE | ID: mdl-21925169

ABSTRACT

Airway epithelial cancer cells produce increased amounts of the chemokine interleukin-8 (IL-8), inducing pro-tumor responses. Multiple stimuli induce airway epithelial IL-8 production epidermal growth factor receptor (EGFR) dependently, but the mechanisms that exaggerate IL-8 production in airway cancers remain unknown. Here we show that direct activation of EGFR (EGFR-P) by its ligand transforming growth factor (TGF)-alpha induces a second EGFR-P in human airway (NCI-H292) cancer cells but not in normal human bronchial epithelial (NHBE) cells, exaggerating IL-8 production in these cancer cells. The second EGFR-P in NCI-H292 cells was caused by metalloprotease TNF-alpha-converting enzyme (TACE)-dependent cleavage of EGFR pro-ligands and was responsible for most of the total IL-8 induced by TGF-alpha. In NCI-H292 cells, TGF-alpha induced cyclooxygenase (COX)-2-dependent prostaglandin (PG)E2 production and release. PGE2 increased the second EGFR-P and IL-8 production via binding to its Gi-protein-coupled E-prostanoid (EP)3 receptor. In NHBE cells, TGF-alpha-induced EGFR-P did not lead to PGE2 production or to a second EGFR-P, and less IL-8 was produced. Thus, we conclude that a positive feedback pathway involving COX-2/PGE2/EP3 receptor-dependent EGFR reactivation exaggerates IL-8 production in NCI-H292 cancer cells but not in NHBE (normal) cells.


Subject(s)
ADAM Proteins/metabolism , ErbB Receptors/metabolism , Feedback, Physiological , Interleukin-8/biosynthesis , Lung Neoplasms/metabolism , Lung Neoplasms/pathology , Receptors, Prostaglandin E, EP3 Subtype/metabolism , ADAM17 Protein , Adenocarcinoma/metabolism , Adenocarcinoma/pathology , Bronchi/cytology , Bronchi/metabolism , Bronchi/pathology , Humans , Tumor Cells, Cultured
11.
J Immunol ; 186(6): 3392-400, 2011 Mar 15.
Article in English | MEDLINE | ID: mdl-21300824

ABSTRACT

Mucous hypersecretion is an important feature of obstructive airway diseases such as asthma, chronic obstructive pulmonary disease, and cystic fibrosis. Multiple stimuli induce mucin production via activation of an epidermal growth factor receptor (EGFR) cascade, but the mechanisms that exaggerate mucin production in obstructive airway diseases remain unknown. In this study, we show that binding of CCL20, a G protein-coupled receptor (GPCR) ligand that is upregulated in the airways of subjects with obstructive airway diseases, to its unique GPCR CCR6 induces MUC5AC mucin production in human airway epithelial (NCI-H292) cells via metalloprotease TNF-α-converting enzyme (TACE)-dependent EGFR activation. We also show that EGFR activation by its potent ligand TGF-α induces reactivation of EGFR via binding of endogenously produced CCL20 to its receptor CCR6 in NCI-H292 cells but not in normal human bronchial epithelial (NHBE) cells, exaggerating mucin production in the NCI-H292 cells. In NCI-H292 cells, TGF-α stimulation induced two phases of EGFR phosphorylation (EGFR-P). The second EGFR-P was TACE-dependent and was responsible for most of the total mucin induced by TGF-α. Binding of endogenously produced CCL20 to CCR6 increased the second EGFR-P and subsequent mucin production induced by TGF-α. In NHBE cells, TGF-α-induced EGFR activation did not lead to significant CCL20 production or to EGFR rephosphorylation, and less mucin was produced. We conclude that NCI-H292 cells but not NHBE cells produce CCL20 in response to EGFR activation, which leads to a second phase of EGFR-P and subsequent exaggerated mucin production. These findings have potentially important therapeutic implications in obstructive airway diseases.


Subject(s)
Chemokine CCL20/physiology , ErbB Receptors/physiology , Feedback, Physiological/physiology , Mucin 5AC/biosynthesis , Receptors, CCR6/physiology , Respiratory Mucosa/immunology , Carcinoma, Mucoepidermoid/immunology , Carcinoma, Mucoepidermoid/metabolism , Carcinoma, Mucoepidermoid/pathology , Cell Communication/immunology , Cell Line, Tumor , Chemokine CCL20/metabolism , ErbB Receptors/metabolism , Humans , Ligands , Lung Neoplasms/immunology , Lung Neoplasms/metabolism , Lung Neoplasms/pathology , Mucin 5AC/antagonists & inhibitors , Mucin 5AC/metabolism , Phosphorylation/immunology , Protein Binding/immunology , Receptors, CCR6/metabolism , Respiratory Mucosa/cytology , Respiratory Mucosa/metabolism , Transforming Growth Factor alpha/metabolism , Transforming Growth Factor alpha/physiology
12.
Am J Physiol Lung Cell Mol Physiol ; 297(1): L174-83, 2009 Jul.
Article in English | MEDLINE | ID: mdl-19429776

ABSTRACT

Mucous hypersecretion is a serious feature of chronic airway diseases such as asthma, chronic obstructive pulmonary disease (COPD), and cystic fibrosis. Although mucins are produced via activation of an EGF receptor (EGFR) signaling cascade, the mechanisms leading to exaggerated mucin production in mucous hypersecretory diseases are unknown. Because expression of ICAM-1 and of the ICAM-1 ligand fibrinogen is increased in the airways of subjects with mucous hypersecretory diseases, we hypothesized that fibrinogen binding to ICAM-1 could increase EGFR-dependent mucin production in human airway (NCI-H292) epithelial cells. Consistent with this hypothesis, we found that an ICAM-1 neutralizing antibody and an ICAM-1(8-22) peptide that binds fibrinogen decreased mucin production induced by the EGFR ligand transforming growth factor (TGF)-alpha dose-dependently. Exogenous fibrinogen and a fibrinogen(117-133) peptide that binds ICAM-1 rescued mucin production in cells treated with the ICAM-1(8-22) peptide. Surprisingly, the ICAM-1(8-22) peptide increased EGFR phosphotyrosine and phospho-ERK1/2 in cells treated with TGF-alpha. The ICAM-1(8-22) peptide-induced increases in EGFR phosphotyrosine and phospho-ERK1/2 were prevented by exogenous fibrinogen, by the fibrinogen(117-133) peptide, and by selective inhibitors of phospholipase C (PLC), protein kinase C (PKC)-alpha/beta, and metalloproteases. These results suggest that fibrinogen binding to ICAM-1 promotes mucin production by decreasing TGF-alpha-induced EGFR and ERK1/2 activation and that the fibrinogen-ICAM-1-dependent decrease in EGFR and ERK1/2 activation occurs via inhibition of an early positive feedback pathway involving PLC- and PKC-alpha/beta-dependent metalloprotease activation and subsequent metalloprotease-dependent EGFR reactivation.


Subject(s)
Epithelial Cells/enzymology , ErbB Receptors/metabolism , Fibrinogen/metabolism , Intercellular Adhesion Molecule-1/metabolism , Lung/cytology , Mucins/biosynthesis , Antibodies/pharmacology , Cell Line, Tumor , Enzyme Activation/drug effects , Epithelial Cells/drug effects , Extracellular Signal-Regulated MAP Kinases/metabolism , Humans , Metalloproteases/metabolism , Models, Biological , Neutralization Tests , Phosphorylation/drug effects , Phosphotyrosine/metabolism , Protein Binding/drug effects , Protein Kinase C/metabolism , Transforming Growth Factor alpha/pharmacology , Type C Phospholipases/metabolism
13.
Appl Environ Microbiol ; 75(10): 3062-8, 2009 May.
Article in English | MEDLINE | ID: mdl-19304836

ABSTRACT

Stereochemical course of isoflavanone dihydrodaidzein (DHD) reduction into the isoflavan (3S)-equol via tetrahydrodaidzein (THD) by the human intestinal anaerobic bacterium Eggerthella strain Julong 732 was studied. THD was synthesized by catalytic hydrogenation, and each stereoisomer was separated by chiral high-performance liquid chromatography. Circular dichroism spectroscopy was used to elucidate the absolute configurations of four synthetic THD stereoisomers. Rapid racemization of DHD catalyzed by Julong 732 prevented the substrate stereospecificity in the conversion of DHD into THD from being confirmed. The absolute configuration of THD, prepared by reduction of DHD in the cell-free incubation, was assigned as (3R,4S) via comparison of the retention time to that of the authentic THD by chiral chromatography. Dehydroequol (DE) was unable to produce the (3S)-equol both in the cell-free reaction and in the bacterial transformation, negating the possible intermediacy of DE. Finally, the intermediate (3R,4S)-THD was reduced into (3S)-equol by the whole cell, indicating the inversion of stereochemistry at C-3 during the reduction. A possible mechanism accounting for the racemization of DHD and the inversion of configuration of THD during reduction into (3S)-equol is proposed.


Subject(s)
Actinobacteria/metabolism , Isoflavones/metabolism , Biotransformation , Chromatography, High Pressure Liquid , Circular Dichroism , Equol , Humans , Metabolic Networks and Pathways , Models, Biological , Stereoisomerism
14.
Biochem Biophys Res Commun ; 371(4): 600-5, 2008 Jul 11.
Article in English | MEDLINE | ID: mdl-18395004

ABSTRACT

Detailed catalytic roles of the conserved Glu323, Asp460, and Glu519 of Arthrobacter sp. S37 inulinase (EnIA), a member of the glycoside hydrolase family 32, were investigated by site-directed mutagenesis and pH-dependence studies of the enzyme efficiency and homology modeling were carried out for EnIA and for D460E mutant. The enzyme efficiency (k(cat)/K(m)) of the E323A and E519A mutants was significantly lower than that of the wild-type due to a substantial decrease in k(cat), but not due to variations in K(m), consistent with their putative roles as nucleophile and acid/base catalyst, respectively. The D460A mutant was totally inactive, whereas the D460E and D460N mutants were active to some extent, revealing Asp460 as a catalytic residue and demonstrating that the presence of a carboxylate group in this position is a prerequisite for catalysis. The pH-dependence studies indicated that the pK(a) of the acid/base catalyst decreased from 9.2 for the wild-type enzyme to 7.0 for the D460E mutant, implicating Asp460 as the residue that interacts with the acid/base catalyst Glu519 and elevates its pK(a). Homology modeling and molecular dynamics simulation of the wild-type enzyme and the D460E mutant shed light on the structural roles of Glu323, Asp460, and Glu519 in the catalytic activity of the enzyme.


Subject(s)
Arthrobacter/enzymology , Bacterial Proteins/chemistry , Glycoside Hydrolases/chemistry , Amino Acid Sequence , Amino Acid Substitution , Aspartic Acid/chemistry , Bacterial Proteins/genetics , Binding Sites , Catalysis , Catalytic Domain , Conserved Sequence , Glutamic Acid/chemistry , Glycoside Hydrolases/genetics , Hydrogen Bonding , Hydrogen-Ion Concentration , Kinetics , Models, Molecular , Molecular Sequence Data , Mutagenesis, Site-Directed , Protein Conformation , Sequence Alignment
15.
J Microbiol Biotechnol ; 17(11): 1811-7, 2007 Nov.
Article in English | MEDLINE | ID: mdl-18092465

ABSTRACT

Extracellular enzymes from Lentinus edodes M290 on normal woods (Quercus mongolica) and waste logs from oak mushroom production were comparatively investigated. Endoglucanase, cellobiohydrolase, beta-glucosidase, and xylanase activities were higher on waste mushroom logs than on normal woods after L. edodes M290 inoculation. Xylanase activity was especially different, with a three times higher activity on waste mushroom logs. When the waste mushroom logs were used as a carbon source, a new 35 kDa protein appeared. After the purification, the optimal pH and temperature for xylanase activity were determined to be 4.0 and 50 degrees C, respectively. More than 50% of the optimal xylanase activity was retained when the temperature was increased from 20 to 60 degrees C, after a 240 min reaction. At 40 degrees C, the xylanase maintained 93% of the optimal activity, after a 240 min reaction. The purified xylanase showed a very high homology to the xylanase family 10 from Aspergillus terreus by LC/MS-MS analysis. The highest Xcorr (1.737) was obtained from the peptide KWI SQGIPIDGIG SQTHLGSGGS WTVK originated from Aspergillus terreus, indicating that the 35 kDa protein was xylanase. This protein showed low homology to a previously reported L. edodes xylanase sequence.


Subject(s)
Endo-1,4-beta Xylanases/metabolism , Shiitake Mushrooms/enzymology , Agaricales , Amino Acid Sequence , Biomass , Endo-1,4-beta Xylanases/chemistry , Endo-1,4-beta Xylanases/isolation & purification , Hydrogen-Ion Concentration , Molecular Sequence Data , Shiitake Mushrooms/growth & development , Temperature
16.
J Microbiol Biotechnol ; 17(1): 37-43, 2007 Jan.
Article in English | MEDLINE | ID: mdl-18051351

ABSTRACT

A gene encoding inulin fructotransferase (di-D-fructofuranose 1,2': 2,3' dianhydride [DFA III]-producing IFTase, EC 4.2.2.18) from Bacillus sp. snu-7 was cloned. This gene was composed of a single, 1,353-bp open reading frame encoding a protein composed of a 40-amino acid signal peptide and a 410-amino acid mature protein. The deduced amino acid sequence was 98% identical to Arthrobacter globiformis C11-1 IFTase (DFA III-producing). The enzyme was successfully expressed in E. coli as a functionally active, His-tagged protein, and it was purified in a single step using immobilized metal affinity chromatography. The purified enzyme showed much higher specific activity (1,276units/mg protein) than other DFA III-producing IFTases. The recombinant and native enzymes were optimally active in very similar pH and temperature conditions. With a 103-min half-life at 60 degrees C, the recombinant enzyme was as stable as the native enzyme. Acidic residues and cysteines potentially involved in the catalytic mechanism are proposed based on an alignment with other IFTases and a DFA IIIase.


Subject(s)
Bacillus/enzymology , Bacillus/genetics , Hexosyltransferases/genetics , Amino Acid Sequence , Base Sequence , Cloning, Molecular , DNA Primers/genetics , DNA, Bacterial/genetics , Enzyme Stability , Escherichia coli/genetics , Gene Expression , Genes, Bacterial , Hexosyltransferases/chemistry , Hexosyltransferases/metabolism , Hydrogen-Ion Concentration , Hydrolysis , Inulin/metabolism , Molecular Sequence Data , Recombinant Proteins/chemistry , Recombinant Proteins/genetics , Recombinant Proteins/metabolism , Sequence Homology, Amino Acid , Temperature
17.
Proc Natl Acad Sci U S A ; 104(52): 20793-8, 2007 Dec 26.
Article in English | MEDLINE | ID: mdl-18087039

ABSTRACT

Posttranslational modification by small ubiquitin-like modifier (SUMO) controls diverse cellular functions of transcription factors and coregulators and participates in various cellular processes including signal transduction and transcriptional regulation. Here, we report that pontin, a component of chromatin-remodeling complexes, is SUMO-modified, and that SUMOylation of pontin is an active control mechanism for the transcriptional regulation of pontin on androgen-receptor target genes in prostate cancer cells. Biochemical purification of pontin-containing complexes revealed the presence of the Ubc9 SUMO-conjugating enzyme that underlies its function as an activator. Intriguingly, 5alpha-dihydroxytestosterone treatments significantly increased the SUMOylation of pontin, and SUMOylated pontin showed further activation of a subset of nuclear receptor-dependent transcription and led to an increase in proliferation and growth of prostate cancer cells. These data clearly define a functional model and provide a link between SUMO modification and prostate cancer progression.


Subject(s)
Carrier Proteins/chemistry , Chromatin/chemistry , DNA Helicases/chemistry , Prostatic Neoplasms/metabolism , Small Ubiquitin-Related Modifier Proteins/chemistry , ATPases Associated with Diverse Cellular Activities , Cell Line, Tumor , Cell Proliferation , Cell Transformation, Neoplastic , Humans , Hydroxytestosterones/pharmacology , Lysine/chemistry , Male , Models, Biological , SUMO-1 Protein , Signal Transduction , Transcription, Genetic , Ubiquitin-Conjugating Enzymes/metabolism
18.
J Biol Chem ; 282(11): 8414-23, 2007 Mar 16.
Article in English | MEDLINE | ID: mdl-17192265

ABSTRACT

Inulin fructotransferase (IFTase), a member of glycoside hydrolase family 91, catalyzes depolymerization of beta-2,1-fructans inulin by successively removing the terminal difructosaccharide units as cyclic anhydrides via intramolecular fructosyl transfer. The crystal structures of IFTase and its substrate-bound complex reveal that IFTase is a trimeric enzyme, and each monomer folds into a right-handed parallel beta-helix. Despite variation in the number and conformation of its beta-strands, the IFTase beta-helix has a structure that is largely reminiscent of other beta-helix structures but is unprecedented in that trimerization is a prerequisite for catalytic activity, and the active site is located at the monomer-monomer interface. Results from crystallographic studies and site-directed mutagenesis provide a structural basis for the exolytic-type activity of IFTase and a functional resemblance to inverting-type glycosyltransferases.


Subject(s)
Fructose/chemistry , Hexosyltransferases/physiology , Amino Acid Sequence , Bacillus/enzymology , Crystallization , Crystallography, X-Ray , DNA Primers/chemistry , Dimerization , Hexosyltransferases/metabolism , Models, Chemical , Molecular Conformation , Molecular Sequence Data , Mutagenesis, Site-Directed , Protein Binding , Protein Conformation , Protein Structure, Secondary , Sequence Homology, Amino Acid
19.
Arch Microbiol ; 187(2): 155-60, 2007 Feb.
Article in English | MEDLINE | ID: mdl-17109177

ABSTRACT

An anaerobic incubation mixture of two bacterial strains Eggerthella sp. Julong 732 and Lactobacillus sp. Niu-O16, which have been known to transform dihydrodaidzein to S-equol and daidzein to dihydrodaidzein respectively, produced S-equol from daidzein through dihydrodaidzein. The biotransformation kinetics of daidzein by the mixed cultures showed that the production of S-equol from daidzein was significantly enhanced, as compared to the production of S-equol from dihydrodaidzein by Eggerthella sp. Julong 732 alone. The substrate daidzein in the mixed culture was almost completely converted to S-equol in 24 h of anaerobic incubation. The increased production of S-equol from daidzein by the mixed culture is likely related to the increased bacterial numbers of Eggerthella sp. Julong 732. In the mixture cultures, the growth of Eggerthella sp. Julong 732 was significantly increased while the growth of Lactobacillus sp. Niu-O16 was suppressed as compared to either the single culture of Eggerthella sp. Julong 732 or Lactobacillus sp. Niu-O16. This is the first report in which two metabolic pathways to produce S-equol from daidzein by a mixed culture of bacteria isolated from human and bovine intestinal environments were successfully linked under anaerobic conditions.


Subject(s)
Bacteria, Anaerobic/growth & development , Bacteria, Anaerobic/metabolism , Isoflavones/biosynthesis , Isoflavones/chemistry , Isoflavones/metabolism , Animals , Bacteria , Bacteria, Anaerobic/isolation & purification , Equol , Humans , Intestines/microbiology , Metabolic Networks and Pathways , Microbiological Techniques , Phytoestrogens/metabolism
20.
J Immunol ; 177(12): 8693-700, 2006 Dec 15.
Article in English | MEDLINE | ID: mdl-17142770

ABSTRACT

The surface of the airway epithelium represents a battleground in which the host intercepts signals from pathogens and activates epithelial defenses to combat infection. Wound repair is an essential function of the airway epithelium in response to injury in chronic airway diseases, and inhaled pathogens such as Pseudomonas bacteria are implicated in the pathobiology of several of these diseases. Because epidermal growth factor receptor (EGFR) activation stimulates wound repair and because LPS activates EGFR, we hypothesized that LPS accelerates wound repair via a surface signaling cascade that causes EGFR phosphorylation. In scrape wounds of NCI-H292 human airway epithelial cells, high concentrations of LPS were toxic and decreased wound repair. However, lower concentrations of LPS accelerated wound repair. This effect was inhibited by treatment with a selective inhibitor of EGFR phosphorylation (AG 1478) and by an EGFR neutralizing Ab. Metalloprotease inhibitors and TNF-alpha-converting enzyme (TACE) small interfering RNA inhibited wound repair, implicating TACE. Additional studies implicated TGF-alpha as the active EGFR ligand cleaved by TACE during wound repair. Reactive oxygen species scavengers, NADPH oxidase inhibitors, and importantly small interfering RNA of dual oxidase 1 inhibited LPS-induced wound repair. Inhibitors of protein kinase C isoforms alphabeta and a TLR-4 neutralizing Ab also inhibited LPS-induced wound repair. Normal human bronchial epithelial cells responded similarly. Thus, LPS accelerates wound repair in airway epithelial cells via a novel TLR-4-->protein kinase C alphabeta-->dual oxidase 1-->reactive oxygen species-->TACE-->TGF-alpha-->EGFR phosphorylation pathway.


Subject(s)
Epithelial Cells/physiology , Lipopolysaccharides/pharmacology , Pseudomonas aeruginosa/chemistry , Signal Transduction/physiology , Wound Healing/drug effects , Cell Line, Tumor , Dose-Response Relationship, Drug , ErbB Receptors/metabolism , Humans , Lipopolysaccharides/therapeutic use , Phosphorylation , Respiratory System/cytology
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