Several different mechanisms have been proposed to explain the possible role of cranberries, cranberry juice, and cranberry extracts in inhibiting bacterial growth. In this report, we showed that Escherichia coli showed slower growth rate in response to the presence of cranberry juice in the growth media. By compareing the global transcript profiles, significant modulation of several genes of E. coli grown in LB broth with 10% cranberry juice were identified and provided identification of the potential mechanisms involved in the inhibitory effects of cranberry juice. The results presented clearly demonstrate that the inhibitory effect on bacterial growth observed in the presence of cranberry juice/extracts is primarily a result of the iron chelation capacity of PACs and direct disruption of metabolic enzymes. The results are discussed with a focus on the genes associated with iron chelation capability.
Impact of cranberry on Escherichia coli cellular surface characteristics.
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View SamplesSince the first generation of induced Pluripotent Stem cells (iPSCs), several reprogramming systems have been used to study its molecular mechanisms. However, the system of choice largely affects the reprogramming efficiency, influencing our view on the mechanisms. Here we demonstrate that reprogramming triggered by less efficient polycistronic reprogramming cassettes not only highlights Mesenchymal-Epithelial Transition (MET) as a roadblock, but also faces more severe difficulties to attain a pluripotent state even post-MET. Also, in contrast to previous findings, more efficient cassettes can reprogram both wild type and Nanog-/- fibroblasts with comparable efficiencies, routes and kinetics, rebutting previous studies that Nanog is critical for iPSC generation. We revealed that the 9 amino acids in the N-terminus of Klf4 in polycistronic reprogramming cassettes are the dominant factor causing these critical differences. Our data establishes that some reprogramming roadblocks are system-dependent, highlighting the need to pursue mechanistic studies with close attention to the systems to better understand reprogramming. Overall design: The aim of the experiment is to compare the reprogramming pathways driven by two different polycistronic cassettes (MKOS and OKMS). We have isolated cells at intermediate stages of both MKOS and OKMS reprogramming and analysed their gene expression profiles. 2N- are CD44- ICAM1-, Nanog-GFP-, 3N- are CD44- ICAM1+, Nanog-GFP-, 3N+ are CD44- ICAM1+, Nanog-GFP+, all from day 10 of reprogramming. MKOS/OKMS iPSCs are established iPSC clones, TNG an Embryonic Stem Cell line carrying a Nanog-GFP reporter published in Chambers et al. Cell, 113, 643-655, from this line TNG MKOS and OKMS Embryonic Stem Cells were generated after targeting the Sp3 locus with the MKOS or the OKMS cassette respectively,E14 a reference Embryonic Stem Cell line and MEF are Mouse Embryonic Fibroblasts either wild type or generaterd from TNG MKOS or OKMS ESCs. D6 is the D6s4B5 iPSC line published in O''Malley et al. Nature, 499, 88-91.
Reprogramming Roadblocks Are System Dependent.
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View SamplesThe efficiency of central nervous system (CNS) remyelination declines with age. This is in part due to an age-associated decline in the phagocytic removal of myelin debris, which contains inhibitors of oligodendrocyte progenitor cell differentiation. In this study we show that expression of genes involved in the retinoid X receptor (RXR) pathway are decreased with aging in myelin-phagocytosing cells. Loss of RXR function in young macrophages mimics aging by delaying remyelination after experimentally-induced demyelination, while RXR agonists partially restore myelin debris phagocytosis in aged macrophages. The FDA-approved RXR agonist bexarotene, when used in concentrations achievable in human subjects, caused a reversion of the gene expression profile in aging human monocytes to a more youthful profile. These results reveal the RXR pathway as a positive regulator of myelin debris clearance and a key player in the age-related decline in remyelination that may be targeted by available or newly-developed therapeutics.
Retinoid X receptor activation reverses age-related deficiencies in myelin debris phagocytosis and remyelination.
Specimen part, Disease, Treatment
View SamplesMicroarrays were used to examine the genome-wide expression in FIH null, VHL null and VHL/FIH double null MEFs.
The asparaginyl hydroxylase factor inhibiting HIF-1alpha is an essential regulator of metabolism.
Specimen part
View SamplesHalf of all human cancers lose p53 function by missense mutations, with an unknown fraction of these containing p53 in a self-aggregated, amyloid-like state. Here we show that a cell-penetrating peptide, ReACp53, designed to inhibit p53 amyloid formation, rescues p53 function in cancer cell lines and in organoids derived from high-grade serous ovarian carcinomas (HGSOC), an aggressive cancer characterized by ubiquitous p53 mutations. Rescued p53 behaves similarly to its wild-type counterpart in regulating target genes, reducing cell proliferation and increasing cell death. Intraperitoneal administration decreases tumor proliferation and shrinks xenografts in vivo. Our data show the effectiveness of targeting a specific aggregation defect of p53 and its potential applicability to HGSOCs. Overall design: Vehicle vs. ReACp53 treatment in 4 different samples: 2 cell lines (MCF7 w/ WT p53 as negative control and OVCAR3 w/ R248Q p53) and 2 clinical specimens (primary cells from patient #8 w/ WT p53 as negative control and primary cells from patient #1 w/ R248Q p53)
A Designed Inhibitor of p53 Aggregation Rescues p53 Tumor Suppression in Ovarian Carcinomas.
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View SamplesDEP exposure is linked to increases in cardiovascular effects. This effect is enhanced in individuals with pre-existing disease. Animal models of cardiovascular disease are used to study this susceptibility. The heart is rich in mitochondria, which produce high levels of free radicals, leading to inactivation of tricarboxylic acid cycle enzymes. We hypothesized that a 4-wk DEP inhalation would result in strain-related structural impairment of cardiac mitochondria and changes in these enzyme activities in WKY and SHR. Male rats (12-14 wks age) were exposed whole body to air or 0.5 or 2.0 mg/m3 DEP for 6h/d, 5 d/wk for 4 wks. Neutrophilic influx was noted in the bronchoalveolar lavage fluid in both strains. A slightly lower level of baseline cardiac mitochondrial aconitase activity was seen in SHR than WKY. Aconitase activity appeared to be decreased in an exposure related manner in both strains. Significantly higher baseline levels of cardiac cytosolic ferritin and aconitase activity were seen in the SHR than WKY. No exposure-related changes were noted in either of these measures. Mitochondrial succinate and isocitrate dehydrogenase activities were not changed following DEP exposure in either strain. Transmission electron microscopy images of the heart indicated abnormalities in cardiac mitochondria of control SHR but not control WKY. No exposure related ultrastructural changes were induced by DEP in either strain. In conclusion, strain differences in cardiac biomarkers of oxidative stress and structure of mitochondria exist between SHR and WKY. DEP exposure results in small changes in cardiac mitochondrial and cytosolic markers of oxidative stress. (Abstract does not represent USEPA policy.)
One-month diesel exhaust inhalation produces hypertensive gene expression pattern in healthy rats.
Specimen part
View SamplesDuring Epithelial-Mesenchymal Transition (EMT), apical-basal polarized epithelial cells are converted to front-to-back polarized mesenchymal cells that only form loose cell-cell adhesions. These phenotypic changes are accompanied by acquisition of increased motility and invasiveness. EMT programs are orchestrated by pleiotropic transcription factors (TFs), such as Twist1 and Snail1 and effect morphogenetic steps during embryogenesis, including mesoderm formation and neural crest migration. EMTs have also been implicated in the acquisition of aggressive traits by carcinoma cells, including the ability to complete several steps of the metastatic cascade as well as propagation of the tumor by single cells (clonogenicity), a defining trait of tumor-initiating or cancer stem cells. However, the molecular links between the expression of EMT-TFs, the process of EMT and acquisition of clonogenicity remain obscure.
Stem-cell-like properties and epithelial plasticity arise as stable traits after transient Twist1 activation.
Sex, Specimen part, Cell line
View SamplesTo delineate gene expression levels in whole non-metastatic and metastatic transplantable primary mouse mammary tumour allografts
Functional and molecular characterisation of EO771.LMB tumours, a new C57BL/6-mouse-derived model of spontaneously metastatic mammary cancer.
Sex
View SamplesMaternal Embryonic Leucine Zipper Kinase (MELK), a Ser/Thr protein kinase, is highly over expressed in stem and cancer cells. The oncogenic role of MELK is attributed to its capacity to disable critical cell cycle checkpoints and to enhance replication. Most functional studies have relied on the use of siRNA/shRNA-mediated gene silencing, but this is often compromised by off target effects. Here we present the cellular validation of a novel, potent and selective small molecule MELK inhibitor, MELK-T1, which has enabled us to explore the biological function of MELK. Strikingly, the binding of MELK-T1 to endogenous MELK triggers a rapid and proteasome dependent degradation of the MELK protein. Treatment of MCF-7 breast adenocarcinoma cells with MELK-T1 leads to an accumulation of stalled replication forks and double strand breaks, followed by a replicative senescence phenotype. This phenotype correlates with a rapid and long-lasting ATM activation and phosphorylation of CHK2. Furthermore, MELK-T1 induces strong phosphorylation of p53 and prolonged up-regulation of p21.
MELK-T1, a small-molecule inhibitor of protein kinase MELK, decreases DNA-damage tolerance in proliferating cancer cells.
Cell line, Treatment
View SamplesThe study aims to determine the set of transcriptional cell types that make up the mouse brain
Molecular Architecture of the Mouse Nervous System.
Sex, Specimen part, Cell line
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