Roles of sumoylation of a reptin chromatin-remodelling complex in cancer metastasis.

Defining the functional modules within transcriptional regulatory factors that govern switching between repression and activation events is a central issue in biology. Recently, we have reported the dynamic role of a beta-catenin-reptin chromatin remodelling complex in regulating a metastasis suppressor gene KAI1 (ref.1), which is capable of inhibiting the progression of tumour metastasis. Here, we identify signalling factors that confer repressive function on reptin and hence repress the expression of KAI1. Biochemical purification of a reptin-containing complex has revealed the presence of specific desumoylating enzymes that reverse the sumoylation of reptin that underlies its function as a repressor. Desumoylation of reptin alters the repressive function of reptin and its association with HDAC1. Furthermore, the sumoylation status of reptin modulates the invasive activity of cancer cells with metastatic potential. These data clearly define a functional model and provide a novel link for SUMO modification in cancer metastasis.

CCL20/CCR6 feedback exaggerates epidermal growth factor receptor-dependent MUC5AC mucin production in human airway epithelial (NCI-H292) cells.

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.

Preparation and characterization of water-reducible polyester resin based on waste PET for insulation varnish.

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.

Epidermal growth factor receptor reactivation induced by E-prostanoid-3 receptor- and tumor necrosis factor-alpha-converting enzyme-dependent feedback exaggerates interleukin-8 production in airway cancer (NCI-H292) cells.

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.

Reactive astrocytes transduce inflammation in a blood-brain barrier model through a TNF-STAT3 signaling axis and secretion of alpha 1-antichymotrypsin.

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.

Light sets the brain's daily clock by regional quickening and slowing of the molecular clockworks at dawn and dusk.

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.

SUMOylation of pontin chromatin-remodeling complex reveals a signal integration code in prostate cancer cells.

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.

Fibrinogen binding to ICAM-1 promotes EGFR-dependent mucin production in human airway epithelial cells.

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.

Stereospecific biotransformation of dihydrodaidzein into (3S)-equol by the human intestinal bacterium Eggerthella strain Julong 732.

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.

Catalytic mechanism of inulinase from Arthrobacter sp. S37.

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.

Functional and structural characterization of a thiol peroxidase from Mycobacterium tuberculosis.

A thiol peroxidase (Tpx) from Mycobacterium tuberculosis was functionally analyzed. The enzyme shows NADPH-linked peroxidase activity using a thioredoxin-thioredoxin reductase system as electron donor, and anti-oxidant activity in a thiol-dependent metal-catalyzed oxidation system. It reduces H2O2, t-butyl hydroperoxide, and cumene hydroperoxide, and is inhibited by sulfhydryl reagents. Mutational studies revealed that the peroxidatic (Cys60) and resolving (Cys93) cysteine residues are critical amino acids for catalytic activity. The X-ray structure determined to a resolution of 1.75 A shows a thioredoxin fold similar to that of other peroxiredoxin family members. Superposition with structural homologues in oxidized and reduced forms indicates that the M. tuberculosis Tpx is a member of the atypical two-Cys peroxiredoxin family. In addition, the short distance that separates the Calpha atoms of Cys60 and Cys93 and the location of these cysteine residues in unstructured regions may indicate that the M. tuberculosis enzyme is oxidized, though the side-chain of Cys60 is poorly visible. It is solely in the reduced Streptococcus pneumoniae Tpx structure that both residues are part of two distinct helical segments. The M. tuberculosis Tpx is dimeric both in solution and in the crystal structure. Amino acid residues from both monomers delineate the active site pocket.

Characterization of xylanase from Lentinus edodes M290 cultured on waste mushroom logs.

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.

Cloning, expression, and characterization of Bacillus sp. snu-7 inulin fructotransferase.

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.

Invasive aspergillosis related to ibrutinib therapy for chronic lymphocytic leukemia.

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.

Crystal structure of a putative pyridoxine 5'-phosphate oxidase (Rv2607) from Mycobacterium tuberculosis.

The three-dimensional structure of Rv2607, a putative pyridoxine 5'-phosphate oxidase (PNPOx) from Mycobacterium tuberculosis, has been determined by X-ray crystallography to 2.5 A resolution. Rv2607 has a core domain similar to known PNPOx structures with a flavin mononucleotide (FMN) cofactor. Electron density for two FMN at the dimer interface is weak despite the bright yellow color of the protein solution and crystal. The shape and size of the putative binding pocket is markedly different from that of members of the PNPOx family, which may indicate some significant changes in the FMN binding mode of this protein relative to members of the family.

The high throughput screening of neuropeptide FF2 receptor ligands from Korean herbal plant extracts.

We have screened 356 libraries of Korean herbal plant extracts to find potential anti-obesity drugs. We employed the recently developed fluorescence polarization high throughput screening (FP HTS) assays of human neuropeptide FF (NPFF) receptors in 384-well microtiter plates. The primary hits were cherry-picked from the libraries and further analyzed by secondary displacement curve assays, in vitro GTPgammaS binding assays and cell-based CRE luciferase reporter assays. Agonists of NPFF receptors showed biphasic affinity curves while the antagonist, BIBP 3226, gave a monophasic affinity curve in competitive binding assays. We isolated and characterized two agonists of human NPFF2 receptor, PC 314 with K(i) of 1.42 microM, and PC 315 with K(i) of 2.17 microM from Schizandra chinensis. PC 314 and PC 315 have been characterized as benzoylgomisin Q (M.W. 552) and gomisin G (M.W. 536). We report that PC 314 and PC 315 are the first non-peptide, natural compounds, which bind to human NPFF2 receptors with good affinity. PC 314 and PC 315 inhibit forskolin-stimulated luciferase expression when CHO cells are co-transfected with NPFF2 receptor and CRE reporter vector. They possess the pharmacological and functional profiles of full agonists. The FP HTS system provides a specific, sensitive and reproducible methodology for studying and screening NPFF receptor ligands.

Laminarin favorably modulates gut microbiota in mice fed a high-fat diet.

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.

The Effects of Costaria costata Extracts on Atopic Dermatitis in an In Vitro Model.

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.