958 research outputs found

    ARHI (DIRAS 3), an Imprinted Tumor Suppressor Gene, Binds to Importins, and Blocks Nuclear Translocation of Stat3

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    ARHI (DIRAS3) is an imprinted tumor suppressor gene whose expression is lost in the majority of breast and ovarian cancers. Unlike its homologs Ras and Rap, ARHI functions as a tumor suppressor. Our previous study showed that ARHI can interact with transcription activator Stat3 and inhibit its nuclear translocation in human breast and ovarian cancer cells. To identify proteins that interact with ARHI in nuclear translocation, we have performed proteomic analysis and identified several importins that can associate with ARHI. To further explore this novel finding, we have purified 10 GST-importin fusion proteins (importin 7, 8, 13, b1, a1, a3, a5, a6, a7 as well as mutant a1). Using a GST-pull down assay, we found that ARHI can bind strongly to most importins; however, its binding is significantly reduced with an importin a1 mutant which contains an altered nuclear localization signal (NLS) domain. In addition, an ARHI N-terminal deletion mutant (NTD) exhibits much less binding to all importins than does wild type ARHI ARHI and NTD proteins were purified and tested for their ability to inhibit nuclear importation of proteins in HeLa cells. ARHI protein inhibits interaction of Ran-importin complexes with GFP fusion proteins that contain an NLS domain and a beta-like import receptor binding domain, blocking their nuclear localization. Addition of ARHI also blocked nuclear localization of phosphorylated Stat3β. By GST-pull down assays, we found that ARHI could compete for Ran-importins binding. Thus, ARHI-induced disruption of importin binding to cargo proteins including Stat3 could serve as an important regulatory mechanism that contributes to the tumor suppressor function of ARHI

    Targeted profiling of chlorinated transformation products and the parent micropollutants in the aquatic environment: A comparison between two coastal cities

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    This study investigated chlorinated transformation products (TPs) and their parent micropollutants, aromatic pharmaceuticals and personal care products (PPCPs) in the urban water bodies of two metropolitan cities. Nine PPCPs and 16 TPs were quantitatively or semi-quantitatively determined using isotope dilution techniques and liquid chromatography-tandem mass spectrometry. TPs and most PPCPs were effectively removed by conventional wastewater treatments in a wastewater treatment plant (WWTP). Chlorinated parabens and all PPCPs (at concentrations below 1000 ng/L) were present in the waters receiving treated wastewater. By contrast, the waters receiving untreated wastewater contained higher levels of PPCPs (up to 9400 ng/L) and more species of chlorinated TPs including chlorinated parabens, triclosan, diclofenac, and bisphenol A. The very different chemical profiles between the water bodies of the two cities of similar geographical and climatic properties may be attributed to their respective uses of chemicals and policies of wastewater management. No apparent increase in the number of species or abundances of TPs was observed in either the chlorinated wastewater or the seawater rich in halogens. This is the first study to elucidate and compare the profiles of multiple TPs and their parent PPCPs in the water bodies of coastal cities from tropical islands. Our findings suggest that chlorinated derivatives of bisphenol A, diclofenac, triclosan, and parabens in the surface water originate from sources other than wastewater disinfection or marine chlorination. Although further studies are needed to identify the origins, conventional wastewater treatments may protect natural water bodies against contamination by those chlorinated substances

    Inhibition of Anchorage-Independent Proliferation and G0/G1 Cell-Cycle Regulation in Human Colorectal Carcinoma Cells by 4,7-Dimethoxy-5-Methyl-l,3-Benzodioxole Isolated from the Fruiting Body of Antrodia camphorate

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    In this study, 4,7-dimethoxy-5-methyl-l,3-benzodioxole (SY-1) was isolated from three different sources of dried fruiting bodies of Antrodia camphorate (AC). AC is a medicinal mushroom that grows on the inner heartwood wall of Cinnamomum kanehirai Hay (Lauraceae), an endemic species that is used in Chinese medicine for its anti-tumor and immunomodulatory properties. In this study, we demonstrated that SY-1 profoundly decreased the proliferation of human colon cancer cells (COLO 205) through G0/G1 cell-cycle arrest (50–150 μM) and induction of apoptosis (>150 μM). Cell-cycle arrest induced by SY-1 was associated with a significant increase in levels of p53, p21/Cip1 and p27/Kip1, and a decrease in cyclins D1, D3 and A. In contrast, SY-1 treatment did not induce significant changes in G0/G1 phase cell-cycle regulatory proteins in normal human colonic epithelial cells (FHC). The cells were cultured in soft agar to evaluate anchorage-independent colony formation, and we found that the number of transformed colonies was significantly reduced in the SY-1-treated COLO 205 cells. These findings demonstrate for the first time that SY-1 inhibits human colon cancer cell proliferation through inhibition of cell growth and anchorage-independent colony formation in soft agar. However, the detailed mechanisms of these processes remain unclear and will require further investigation

    Switch activation of PI-PLC downstream signals in activated macrophages with wortmannin

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    AbstractPhosphatidylinositol (4,5)-bisphosphate (PtdIns(4,5)P2) has been known to serve as a substrate for phosphatidylinositol 3-kinase (PI3K) and phosphoinositide-specific phospholipase C (PI-PLC), which can produce PtdIns(3,4,5)P3 and inositol 1,4,5-trisphosphate (Ins(1,4,5)P3) and diacylglycerol (DAG), respectively. In this study, we elucidated the role of PI-PLC during the LPS-activated mouse macrophages RAW264.7 treated with PI3K inhibitor wortmannin. First, wortmannin treatment enhanced Ins(1,4,5)P3 production and iNOS expression in LPS-activated macrophages. Inhibition of PI3K by p85 siRNA also showed an enhancement of iNOS expression. On the other hand, overexpression of PI3K by ras-p110 expression plasmid significantly decreased iNOS expression in LPS-activated macrophages. In addition, overexpression of wild-type or dominant-negative Akt expression plasmid did not affect the iNOS expression in LPS-activated macrophages. Second, treatment of PI-PLC inhibitor U73122 reversed the enhancement of iNOS expression, the increase of phosphorylation level of ERK, JNK and p38, and the increase of AP-1-dependent gene expression in wortmannin-treated and LPS-activated macrophages. However, NF-κB activity determined by EMSA assay and reporter plasmid assay did not change during LPS-activated macrophages with or without wortmannin. We propose that the inhibition of PI3K by wortmannin in mouse macrophages enhances the PI-PLC downstream signals, and subsequently increases the LPS induction of iNOS expression independently of Akt pathway

    Apyrase treatment prevents ischemia–reperfusion injury in rat lung isografts

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    ObjectiveEndothelial cells express the ectoenzyme ectonucleoside adenosine triphosphate diphosphohydrolase, an apyrase that inhibits vascular inflammation by catalyzing the hydrolysis of adenosine triphosphate and adenosine diphosphate. However, ectonucleoside adenosine triphosphate diphosphohydrolase expression is rapidly lost following oxidative stress, leading to the potential for adenosine triphosphate and related purigenic nucleotides to exacerbate acute solid organ inflammation and injury. We asked if administration of a soluble recombinant apyrase APT102 attenuates lung graft injury in a cold ischemia reperfusion model of rat syngeneic orthotopic lung transplantation.MethodsMale Fisher 344 donor lungs were cold preserved in a low-potassium dextrose solution in the presence or absence of APT102 for 18 hours prior to transplantation into syngeneic male Fisher 344 recipients. Seven minutes after reperfusion, lung transplant recipients received either a bolus of APT102 or vehicle (saline solution). Four hours after reperfusion, APT102- and saline solution–treated groups were evaluated for lung graft function and inflammation.ResultsAPT102 significantly reduced lung graft extracellular pools of adenosine triphosphate and adenosine diphosphate, improved oxygenation, and protected against pulmonary edema. Apyrase treatment was associated with attenuated neutrophil graft sequestration and less evidence of tissue inflammation as assessed by myeloperoxidase activity, expression of proinflammatory mediators, and numbers of apoptotic endothelial cells.ConclusionsAdministration of a soluble recombinant apyrase promotes lung function and limits the tissue damage induced by prolonged cold storage, indicating that extracellular purigenic nucleotides play a key role in promoting ischemia–reperfusion injury following lung transplantation

    Mass spectrometry-based lipidomics to explore the biochemical effects of naphthalene toxicity or tolerance in a mouse mode

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    Naphthalene causes mouse airway epithelial injury. However, repeated exposures of naphthalene result in mouse airway tolerance. Previous results showed that toxicity or tolerance was correlated with changes of phosphorylcholine-containing lipids. In this study, a mass spectrometry-based lipidomic approach was applied to examine the effects of naphthaleneinduced injury or tolerance in the male ICR mice. The injury model was vehicle x 7 plus 300 mg/kg naphthalene while the tolerant one was 200 mg/kg daily x 7 followed by 300 mg/kg naphthalene on day 8. The lung, liver, kidney, and serum samples were collected for profiles of phosphorylcholine-containing lipids including phosphatidylcholines (PCs) and sphingomyelins (SMs). A partial least-square-discriminate analysis model showed different lung phosphorylcholine-containing lipid profiles from the injured, tolerant, and control groups. Perturbation of diacyl-PCs and plasmenylcholines may be associated with enhanced membrane flexibility and anti-oxidative mechanisms in the lungs of tolerant mice. Additionally, alterations of lyso-PCs and SMs may be responsible for pulmonary dysfunction and inflammation in the lungs of injured mice. Moreover, serum PC(16:0/18:1) has potential to reflect naphthalene-induced airway injuries. Few phosphorylcholine-containing lipid alterations were found in the mouse livers and kidneys across different treatments. This study revealed the changes in lipid profiles associated with the perturbations caused by naphthalene tolerance and toxicity; examination of lipids in serum may assist biomarker development with the potential for application in the human population

    An Antireflective Nanostructure Array Fabricated by Nanosilver Colloidal Lithography on a Silicon Substrate

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    An alternative method is presented for fabricating an antireflective nanostructure array using nanosilver colloidal lithography. Spin coating was used to produce the multilayered silver nanoparticles, which grew by self-assembly and were transformed into randomly distributed nanosilver islands through the thermodynamic action of dewetting and Oswald ripening. The average size and coverage rate of the islands increased with concentration in the range of 50–90 nm and 40–65%, respectively. The nanosilver islands were critically affected by concentration and spin speed. The effects of these two parameters were investigated, after etching and wet removal of nanosilver residues. The reflection nearly disappeared in the ultraviolet wavelength range and was 17% of the reflection of a bare silicon wafer in the visible range

    Ell3 Enhances Differentiation of Mouse Embryonic Stem Cells by Regulating Epithelial-Mesenchymal Transition and Apoptosis

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    Ell3 is a testis-specific RNA polymerase II elongation factor whose cellular function is not clear. The present study shows that Ell3 is activated during the differentiation of mouse embryonic stem cells (mESCs). Furthermore, Ell3 plays a critical role in stimulating lineage differentiation of mESCs by promoting epithelial-mesenchymal transition (EMT) and suppressing apoptosis. Mouse ESCs engineered to stably express Ell3 were rapidly differentiated compared with control cells either under spontaneous differentiation or neural lineage-specific differentiation conditions. Gene expression profile and quantitative RT-PCR analysis showed that the expression of EMT markers, such as Zeb1 and Zeb2, two major genes that regulate EMT, was upregulated in Ell3-overexpressing mESCs. Remarkably, knockdown of Zeb1 attenuated the enhanced differentiation capacity of Ell3-overexpressing mESCs, which indicates that Ell3 plays a role in the induction of mESC differentiation by inducing EMT. In contrast to Ell3-overexpressing mESCs, Ell3-knock down mESCs could not differentiate under differentiation conditions and, instead, underwent caspase-dependent apoptosis. In addition, apoptosis of differentiating Ell3-knock out mESCs was associated with enhanced expression of p53. The present results suggest that Ell3 promotes the differentiation of mESCs by activating the expression of EMT-related genes and by suppressing p53 expression

    Antimicrobial resistance among migrants in Europe: a systematic review and meta-analysis

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    BACKGROUND: Rates of antimicrobial resistance (AMR) are rising globally and there is concern that increased migration is contributing to the burden of antibiotic resistance in Europe. However, the effect of migration on the burden of AMR in Europe has not yet been comprehensively examined. Therefore, we did a systematic review and meta-analysis to identify and synthesise data for AMR carriage or infection in migrants to Europe to examine differences in patterns of AMR across migrant groups and in different settings. METHODS: For this systematic review and meta-analysis, we searched MEDLINE, Embase, PubMed, and Scopus with no language restrictions from Jan 1, 2000, to Jan 18, 2017, for primary data from observational studies reporting antibacterial resistance in common bacterial pathogens among migrants to 21 European Union-15 and European Economic Area countries. To be eligible for inclusion, studies had to report data on carriage or infection with laboratory-confirmed antibiotic-resistant organisms in migrant populations. We extracted data from eligible studies and assessed quality using piloted, standardised forms. We did not examine drug resistance in tuberculosis and excluded articles solely reporting on this parameter. We also excluded articles in which migrant status was determined by ethnicity, country of birth of participants' parents, or was not defined, and articles in which data were not disaggregated by migrant status. Outcomes were carriage of or infection with antibiotic-resistant organisms. We used random-effects models to calculate the pooled prevalence of each outcome. The study protocol is registered with PROSPERO, number CRD42016043681. FINDINGS: We identified 2274 articles, of which 23 observational studies reporting on antibiotic resistance in 2319 migrants were included. The pooled prevalence of any AMR carriage or AMR infection in migrants was 25·4% (95% CI 19·1-31·8; I2 =98%), including meticillin-resistant Staphylococcus aureus (7·8%, 4·8-10·7; I2 =92%) and antibiotic-resistant Gram-negative bacteria (27·2%, 17·6-36·8; I2 =94%). The pooled prevalence of any AMR carriage or infection was higher in refugees and asylum seekers (33·0%, 18·3-47·6; I2 =98%) than in other migrant groups (6·6%, 1·8-11·3; I2 =92%). The pooled prevalence of antibiotic-resistant organisms was slightly higher in high-migrant community settings (33·1%, 11·1-55·1; I2 =96%) than in migrants in hospitals (24·3%, 16·1-32·6; I2 =98%). We did not find evidence of high rates of transmission of AMR from migrant to host populations. INTERPRETATION: Migrants are exposed to conditions favouring the emergence of drug resistance during transit and in host countries in Europe. Increased antibiotic resistance among refugees and asylum seekers and in high-migrant community settings (such as refugee camps and detention facilities) highlights the need for improved living conditions, access to health care, and initiatives to facilitate detection of and appropriate high-quality treatment for antibiotic-resistant infections during transit and in host countries. Protocols for the prevention and control of infection and for antibiotic surveillance need to be integrated in all aspects of health care, which should be accessible for all migrant groups, and should target determinants of AMR before, during, and after migration. FUNDING: UK National Institute for Health Research Imperial Biomedical Research Centre, Imperial College Healthcare Charity, the Wellcome Trust, and UK National Institute for Health Research Health Protection Research Unit in Healthcare-associated Infections and Antimictobial Resistance at Imperial College London
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