Search results for "Gene expression"
showing 10 items of 4085 documents
Sequential Hepatogenic Transdifferentiation of Adipose Tissue-Derived Stem Cells: Relevance of Different Extracellular Signaling Molecules, Transcrip…
2009
Adipose tissue contains a mesenchymal stein cell (MSC) population Known as adipose-derived stein cells (ASCs) capable of differentiating into different cell types. Our aim was to induce hepatic transdifferentiation of ASCs by sequential exposure to several combinations of cytokines, growth factors, and hormones. The most efficient hepatogenic protocol includes fibroblastic growth factors (FGF) 2 and 4 and epidermal growth factor (EGF) (step 1), hepatocyte growth factor (HGF), FGF2, FGF4, and nicotinamide (Nic) (step 2), and oncostatin M (OSM), dexamethasone (Dex), and insulin-tranferrin-selenium (step 3). This protocol activated transcription factors [GATA6, Hex, CCAAT/enhancer binding prot…
Sensitivity of neuronal nicotinic acetylcholine receptors to the opiate antagonists naltrexone and naloxone: receptor blockade and up-regulation
2003
In HEK293 cells stably expressing alpha4beta2 nAChRs, naltrexone, but not naloxone, blocked alpha4beta2 nAChRs via an open-channel blocking mechanism. In primary hippocampal cultures, naltrexone inhibited alpha7 nAChRs up-regulated by nicotine, and in organotypic hippocampal cultures naltrexone caused a time-dependent up-regulation of functional alpha7 nAChRs that was detected after removal of the drug. These results indicate that naltrexone could be used as a smoking cessation aid.
Metabolic profiling reveals distinct variations linked to nicotine consumption in humans--first results from the KORA study.
2008
Exposure to nicotine during smoking causes a multitude of metabolic changes that are poorly understood. We quantified and analyzed 198 metabolites in 283 serum samples from the human cohort KORA (Cooperative Health Research in the Region of Augsburg). Multivariate analysis of metabolic profiles revealed that the group of smokers could be clearly differentiated from the groups of former smokers and non-smokers. Moreover, 23 lipid metabolites were identified as nicotine-dependent biomarkers. The levels of these biomarkers are all up-regulated in smokers compared to those in former and non-smokers, except for three acyl-alkyl-phosphatidylcholines (e.g. plasmalogens). Consistently significant r…
Reciprocal regulation of endothelial nitric-oxide synthase and NADPH oxidase by betulinic acid in human endothelial cells.
2007
Nitric oxide (NO) produced by endothelial NO synthase (eNOS) is a protective principle in the vasculature. Many cardiovascular diseases are associated with reduced NO bioactivity and eNOS uncoupling due to oxidative stress. Compounds that reverse eNOS uncoupling and increase eNOS expression are of therapeutic interest. Zizyphi Spinosi semen (ZSS) is one of the most widely used traditional Chinese herbs with protective effects on the cardiovascular system. In human umbilical vein endothelial cells (HUVEC) and HUVEC-derived EA.hy 926 cells, an extract of ZSS increased eNOS promoter activity, eNOS mRNA and protein expression, and NO production in a concentration- and time-dependent manner. Maj…
Ursolic acid from the Chinese herb Danshen (Salvia miltiorrhiza L.) upregulates eNOS and downregulates Nox4 expression in human endothelial cells
2007
Danshen, the dried root of Salvia miltiorrhiza Bunge (Lamiaceae), is one of the most commonly used traditional Chinese medicines for cardiovascular indications. In EA.hy 926 cells, a cell line derived from human umbilical vein endothelial cells (HUVEC), an aqueous extract of danshen, and also a methanol extract of the plant, increased eNOS promoter activity, eNOS mRNA and protein expression, as well as endothelial NO production. A dichloromethane extract, in contrast, did not change eNOS gene expression. Thus, the active danshen constituent(s) responsible for eNOS upregulation is (are) hydrophilic and/or alcohol-soluble. One such compound is ursolic acid that significantly increased eNOS ex…
Sporogen, S14-95, and S-curvularin, three inhibitors of human inducible nitric-oxide synthase expression isolated from fungi.
2003
The induction of human inducible nitric-oxide synthase (iNOS) expression depends (among other factors) on activation of the signal transducer and activator of transcription 1 (STAT1) pathway. Therefore, the STAT1 pathway may be an appropriate target for the development of inhibitors of iNOS expression. HeLa S3 cells transiently transfected with a gamma-activated site (GAS)/interferon-stimulated response element-driven reporter gene construct were used as the primary screening system. Using this system, three novel inhibitors of interferon-gamma-dependent gene expression, namely, sporogen, S14-95, and S-curvularin, were isolated from different Penicillium species. These three compounds also …
Genetic and Environmental Controls on Nitrous Oxide Accumulation in Lakes
2015
We studied potential links between environmental factors, nitrous oxide (N2O) accumulation, and genetic indicators of nitrite and N2O reducing bacteria in 12 boreal lakes. Denitrifying bacteria were investigated by quantifying genes encoding nitrite and N2O reductases (nirS/nirK and nosZ, respectively, including the two phylogenetically distinct clades nosZ(I) and nosZ(II)) in lake sediments. Summertime N2O accumulation and hypolimnetic nitrate concentrations were positively correlated both at the inter-lake scale and within a depth transect of an individual lake (Lake Vanajavesi). The variability in the individual nirS, nirK, nosZ(I), and nosZ(II) gene abundances was high (up to tenfold) a…
Peptidases specific for proline-containing peptides and their unusual peptide-dependent regulation in Oenococcus oeni
2009
International audience; Growth of the lactic acid bacterium (LAB) Oenococcus oeni, which is involved in malolactic fermentation during the winemaking process, is stimulated by peptides originating from yeast. In this study, we investigated the impact of peptides on O. oeni growth, peptidase activity and the expression of genes encoding the studied peptidases. Low levels of PepN activity and very high levels of PepI activity were observed in O. oeni, whereas levels of PepX activity were intermediate. The level of biosynthesis of these O. oeni peptidases was shown to depend on peptides present in the culture medium. These results were confirmed by transcriptional analyses of putative pep gene…
Aging-related endothelial dysfunction in the aorta from female senescence-accelerated mice is associated with decreased nitric oxide synthase express…
2013
The present study investigated the time-course for aging-associated effects on contractile and relaxing vascular responses and nitric oxide (NO) production in the aorta from female senescence-accelerated resistant (SAMR1) and prone (SAMP8) mice. Both SAMR1 and SAMP8 were studied at three different ages: 3 (young), 6 (middle age) and 10 (old) months. Concentration-response curves to phenylephrine (10(-8) to 10(-5) M) or acetylcholine (10(-9) to 10(-5) M) were performed in the aortic rings in the absence or in the presence of NO synthase (NOS) inhibitor L-NAME (10(-4) M). Protein and gene expression for endothelial NOS (eNOS) was determined by immunofluorescence, Western blot and real-time PC…
Functional characterization of protein variants of the human multidrug transporter ABCC2 by a novel targeted expression system in fibrosarcoma cells
2012
The multidrug resistance-associated protein 2 (MRP2/ABCC2) is involved in the efflux of endogenous and xenobiotic substrates, including several anticancer and antiviral drugs. The functional consequences of ABCC2 protein variants remain inconsistent, which may be due to shortcomings of the in vitro assays used. To study systematically the functional consequences of nonsynonymous ABCC2 variants, we used a novel “Screen and Insert” (ScIn) technology to achieve stable and highly reproducible expression of 13 ABCC2 variants in HT1080 cells. Western blotting revealed lower (30–65%) ABCC2 expression for D333G, R1174H, and R1181L as compared with wild type (WT; 100%), whereas the linked variant V1…