Despite accepted health benefits of dietary fiber, little is known about the mechanisms by which fiber deprivation impacts the gut microbiota and alters disease risk. Using a gnotobiotic model, in which mice were colonized with a synthetic human gut microbiota, we elucidated the functional interactions between dietary fiber, the gut microbiota and the colonic mucus barrier, which serves as a primary defence against pathogens. We show that during chronic or intermittent dietary fiber deficiency, the gut microbiota resorts to host-secreted mucus glycoproteins as a nutrient source, leading to erosion of the colonic mucus barrier. Dietary fiber deprivation promoted greater epithelial access and lethal colitis by the mucosal pathogen, Citrobacter rodentium, but only in the presence of a fiber-deprived microbiota that is pushed to degrade the mucus layer. Our work reveals intricate pathways linking diet, gut microbiome and intestinal barrier dysfunction, which could be exploited to improve health using dietary therapeutics.
A Dietary Fiber-Deprived Gut Microbiota Degrades the Colonic Mucus Barrier and Enhances Pathogen Susceptibility.
Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Integrated approaches to miRNAs target definition: time-series analysis in an osteosarcoma differentiative model.
Specimen part, Cell line, Time
View SamplesWe explored the transcriptional modification induced by CD99 transfection in the osteosarcoma cell lines SaOS-2 after 0, 7 and 14 days in differentiation medium.
Integrated approaches to miRNAs target definition: time-series analysis in an osteosarcoma differentiative model.
Specimen part, Cell line, Time
View Samplesß1-integrin is the major ß-integrin subunit expressed in both lens epithelial and fiber cells. Our previous research indicated that ß1-integrin is essential for the maintenance of lens epithelial integrity and survival in late embryonic lens development (Simirskii et al, 2009). Lack of ß1-integrin in the lens will lead to severe micropthalmia and lack of lens in adult mice. In order to study the mechanisms involved, high throughput RNA sequencing (RNAseq) was performed to determine the genes that are differentially expressed between E15.5 wild type (WT) lenses and lenses that lack ß1-integrin expression due to the action of MLR10 CRE (ß1-cKO). The methodology used here is similar to the other RNAseq experiments that were previously performed in our lab (Manthey et al., 2014a and Audette et al, 2015) (Geo accession: GSE 49949 and GSE69940) . Meanwhile, the filtering criteria and processing procedures were also published (Manthey et al., 2014b). Compared to WT, 120 genes were found to be differentially expressed in ß1-cKO lenses. Moreover, bioinformatics tools (DAVID (the database for Annotation, Visulization and Integrated Discovery), and PANTHER (Protein Analysis through Evolutionary Relationship) classification system) as well as manual literature searching was applied for further data analysis. It showed that genes involved in EMT and stress-responses were differentially expressed in ß1-cKO compared to that of WT. Description of filtering criteria: To identify the differentially expressed genes, pair-wise qCML method exact tests with a Benjamini Hochberg false discovery rate correction greater than the threshold of P<0.05 was applied, which identified 5120 genes. As previously described (Manthey et al., 2014b), most of the genes differentially expressed between inbred C57Bl/6 <har> and mice with a mixed background were below a threshold of 2.5 fold change. Therefore, all differentially expressed genes with a less than 2.5 fold change were filtered out. Further, genes whose expression level were not high enough to be biologically significant were also filtered out, based on the RPMK (Reads per Kilobase per million reads) value. Any gene in the final list has RPKM greater that 2 in either WT or ß1-cKO samples, a value that corresponds to approximately 1 mRNA molecule per cell. By applying a combination of these filtering criteria, 120 differentially expressed genes were found, which could potentially elucidate the molecular connections between conditional deletion of ß1-intergrin from the lens and the observed phenotypic abnormalities. Manthey, A. L., Lachke, S. A., FitzGerald, P. G., Mason, R. W., Scheiblin, D. A., McDonald, J. H. and Duncan, M. K. (2014a) ''Loss of Sip1 leads to migration defects and retention of ectodermal markers during lens development'', Mech Dev 131: 86-110. Manthey, A. L., Terrell, A. M., Lachke, S. A., Polson, S. W. and Duncan, M. K. (2014b) ''Development of novel filtering criteria to analyze RNA-sequencing data obtained from the murine ocular lens during embryogenesis'', Genom Data 2: 369-374. Overall design: RNA-Seq comparison of C57Bl/6 <har> wild type controls and ß1-integrin conditional knockout lenses at E15.5, three biological replicates were used in each group
β1-Integrin Deletion From the Lens Activates Cellular Stress Responses Leading to Apoptosis and Fibrosis.
Specimen part, Subject
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Dynamic changes in 5-hydroxymethylation signatures underpin early and late events in drug exposed liver.
Sex, Specimen part, Treatment, Time
View SamplesHepatitis C virus (HCV) infection is a major cause of chronic liver disease worldwide. The current standard therapy for chronic hepatitis C (CHC) consists of a combination of pegylated IFN alpha (pegIFN-alpha) and ribavirin. It achieves a sustained viral clearance in only 5060% of patients. To learn more about molecular mechanisms underlying treatment failure, we investigated IFN-induced signaling in paired liver biopsies collected from CHC patients before and after administration of pegIFN-alpha. In patients with a rapid virological response to treatment, pegIFN-alpha induced a strong up-regulation of IFN-stimulated genes (ISGs). As shown previously, nonresponders had high expression levels of ISGs before therapy. Analysis of posttreatment biopsies of these patients revealed that pegIFN-alpha did not induce expression of ISGs above the pretreatment levels. In accordance with ISG expression data, phosphorylation, DNA binding, and nuclear localization of STAT1 indicated that the IFN signaling pathway in nonresponsive patients is preactivated and refractory to further stimulation. Some features characteristic of nonresponders were more accentuated in patients infected with HCV genotypes 1 and 4 compared with genotypes 2 and 3, providing a possible explanation for the poor response of the former group to therapy. Taken together with previous findings, our data support the concept that activation of the endogenous IFN system in CHC not only is ineffective in clearing the infection but also may impede the response to therapy, most likely by inducing a refractory state of the IFN signaling pathway.
Interferon signaling and treatment outcome in chronic hepatitis C.
No sample metadata fields
View SamplesDynamic changes in the mouse liver DNA methylome associated with short (1 day) and prolonged (7, 28 and 91 days) exposure to the rodent liver non-genotoxic carcinogen (NGC), phenobarbital (PB).
Dynamic changes in 5-hydroxymethylation signatures underpin early and late events in drug exposed liver.
Specimen part, Treatment
View Samples29-32 days old male mice where either treated with Phenobarbital or untreated
Dynamic changes in 5-hydroxymethylation signatures underpin early and late events in drug exposed liver.
Sex, Specimen part, Treatment, Time
View SamplesThe effect of cafeteria (CAF) diet in PBMC gene expression was analyzed in two inbred rat strains
Identification of a nutrient-sensing transcriptional network in monocytes by using inbred rat models on a cafeteria diet.
Sex, Specimen part
View SamplesOral cancer kills about 1 person every hour each day in the United States and is the 6th most prevalent cancer worldwide. In this study we utilized existing microarray data from a prior oral cancer study to examine the role of chronic pro-inflammatory mediators in oral carcionogenesis by comparing gene expression in oral tumors with adjacent non-tumor oral tissue from the same patient
Deletion of macrophage migration inhibitory factor inhibits murine oral carcinogenesis: Potential role for chronic pro-inflammatory immune mediators.
Disease, Subject
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