Epithelial cells of the mammalian intestine are covered with a mucus layer that prevents direct contact with intestinal microbes but also constitutes a substrate for mucus-degrading bacteria. To study the effect of mucus degradation on the host response, germ-free mice were colonized with Akkermansia muciniphila. This anaerobic bacterium belonging to the Verrucomicrobia is specialized in the degradation of mucin, the glycoprotein present in mucus, and found in high numbers in the intestinal tract of human and other mammalian species. Efficient colonization of A. muciniphila was observed with highest numbers in the cecum, where most mucin is produced. In contrast, following colonization by Lactobacillus plantarum, a facultative anaerobe belonging to the Firmicutes that ferments carbohydrates, similar cell-numbers were found at all intestinal sites. Whereas A. muciniphila was located closely associated with the intestinal cells, L. plantarum was exclusively found in the lumen. The global transcriptional host response was determined in intestinal biopsies and revealed a consistent, site-specific, and unique modulation of about 750 genes in mice colonized by A. muciniphila and over 1500 genes after colonization by L. plantarum. Pathway reconstructions showed that colonization by A. muciniphila altered mucosal gene expression profiles toward increased expression of genes involved in immune responses and cell fate determination, while colonization by L. plantarum led to up-regulation of lipid metabolism. These indicate that the colonizers induce host responses that are specific per intestinal location. In conclusion, we propose that A. muciniphila modulates pathways involved in establishing homeostasis for basal metabolism and immune tolerance toward commensal microbiota.
Modulation of Mucosal Immune Response, Tolerance, and Proliferation in Mice Colonized by the Mucin-Degrader Akkermansia muciniphila.
Sex, Specimen part
View SamplesDietary polyunsaturated fatty acids (PUFA) act as potent natural hypolipidemics and are linked to many health benefits in humans and in animal models. Mice fed long-term a high fat diet, in which medium-chain alpha linoleic acid (ALA) was partially replaced by long-chain docosahexaenoic (DHA) and eicosapentaenoic (EPA) fatty acids, showed reduced accumulation of body fat and prevention of insulin resistance, besides increased mitochondrial beta-oxidation in white adipose tissue and decreased plasma lipids. ALA, EPA and DHA all belong to PUFA of n-3 series. The intestine is a gatekeeper organ for ingested lipids. To examine the potential contribution of the intestine in the beneficial effects of EPA and DHA, this study assessed gene expression changes using whole genome microarray analysis on small intestinal scrapings. The main biological process affected was lipid metabolism. Fatty acid uptake, peroxisomal and mitochondrial beta-oxidation, and omega-oxidation of fatty acids were all increased. Quantitative real time PCR and intestinal fatty acid oxidation measurements ([14C(U)]-palmitate) confirmed significant gene expression differences in a dose-dependent manner. Furthermore, no major changes in the expression of lipid metabolism genes were observed in colonic scrapings. In conclusion, we show that marine n-3 fatty acids regulate small intestinal gene expression patterns. Since this organ contributes significantly to whole organism energy use, this adaptation of the small intestine may contribute to the complex and observed beneficial physiological effects of these natural compounds under conditions that will normally lead to development of obesity and diabetes.
Induction of lipid oxidation by polyunsaturated fatty acids of marine origin in small intestine of mice fed a high-fat diet.
No sample metadata fields
View SamplesTo identify a cohort of rhythmically expressed genes in the murine Distal Colon,microarrays were used to measure gene expression over a 24-hour light/dark cycle.The rhythmic transcripts were classified according to expression patterns, functions and association with physiological and pathophysiological processes of the colon including motility, colorectal cancer formation and inflammatory bowel disease.
Transcriptional profiling of mRNA expression in the mouse distal colon.
No sample metadata fields
View SamplesNeo/null loss of Tfap2a in E10.5 mouse facial prominences
Tfap2a-dependent changes in mouse facial morphology result in clefting that can be ameliorated by a reduction in Fgf8 gene dosage.
Specimen part
View SamplesThe mammalian gastrointestinal tract harbors thousands of bacterial species that include symbionts as well as potential pathogens. The immune responses that limit access of these bacteria to underlying tissue remain poorly defined.
Gammadelta intraepithelial lymphocytes are essential mediators of host-microbial homeostasis at the intestinal mucosal surface.
Specimen part
View SamplesIntestinal polyposis, a precancerous neoplasia, results primarily from an abnormal increase in the number of crypts. Crypts contain intestinal stem cells (ISCs). Thus intestinal polyposis provides an ideal condition for studying stem cell involvement in polyp/tumor formation. Using a conditional knock-out mouse model, we found that the tumor suppressor Phosphatase of Tension homolog (PTEN) governs the proliferation rate and number of ISCs and loss of PTEN results in an excess of ISCs. In PTEN mutants, excess ISCs initiate de-novo crypt formation and crypt fission, recapitulating crypt production in fetal/neonatal intestine. Microarray studies were used to profile the changes in gene expression that occurred when PTEN was knocked out in the intestine.
PTEN-deficient intestinal stem cells initiate intestinal polyposis.
No sample metadata fields
View SamplesTransfection of a Kaposi's sarcoma (KS) herpesvirus (KSHV) Bacterial Artificial Chromosome (KSHVBac36) into mouse bone marrow endothelial lineage cells generated a cell (mECK36) that induced KS-like tumors in mice. mECK36 formed KSHV-harboring vascularized spindle-cell sarcomas that were LANA+ and displayed a KSHV and host transcriptomes reminiscent of KS tumors.
In vivo-restricted and reversible malignancy induced by human herpesvirus-8 KSHV: a cell and animal model of virally induced Kaposi's sarcoma.
No sample metadata fields
View SamplesQuetiapine is an atypical neuroleptic with a pharmacological profile distinct from classic neuroleptics. It is currently approved for treating patients with schizophrenia, major depression and bipolar I disorder. However, its cellular effects remain elusive.
Unique pharmacological actions of atypical neuroleptic quetiapine: possible role in cell cycle/fate control.
Sex, Treatment
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Evolutionary etiology of high-grade astrocytomas.
Sex, Time
View SamplesTo determine the regulatory pathways necessary for astrocytoma formation within complex adult brain microenvironments, we engineered mice for adult astrocyte-specific disruption of key regulators (pRb, Kras and Pten). Drivers of all astrocytoma grades were identified using CreERTM-inducible alleles. Inactivation of pRb was necessary to initiate grade II disease, and was the only lesion to do so. Additional activation of Kras progressed disease to grade III, while further Pten inactivation facilitated grade IV (glioblastoma) progression. These outcomes were elicited whether somatic events were induced broadly or focally. In vivo inactivation of pRb, which induced astrocyte proliferation and apoptosis, activated the MAPK pathway, while Kras activation and Pten loss triggered PI3K pathways.
Evolutionary etiology of high-grade astrocytomas.
Sex, Time
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