The thymus is extremely sensitive to damage but also has a remarkable ability to repair itself. However, the mechanisms underlying this endogenous regeneration remain poorly understood and this capacity diminishes considerably with age. To identify alternate regeneration pathways in the thymus, we performed an unbiased transcriptome analysis of the non-hematopoietic (CD45-) stromal cell compartment of the thymus, which is less sensitive to thymic damage compared to the CD45+ hematopoietic compartment.
Production of BMP4 by endothelial cells is crucial for endogenous thymic regeneration.
Sex, Specimen part
View SamplesWe studied the effect of dietary fat type, varying in polyunsaturated/saturated fatty acid ratio's (P/S) on development of metabolic syndrome. C57Bl/6J mice were fed purified high-fat diets (45E% fat) containing palm oil (HF-PO; P/S 0.4), olive oil (HF-OO; P/S 1.1) or safflower oil (HF-SO; P/S 7.8) for 8 weeks. A low-fat palm oil diet (LF-PO; 10E% fat) was used as a reference. Additionally, we analyzed diet-induced changes in gut microbiota composition and mucosal gene expression. The HF-PO diet induced a higher body weight gain and liver triglyceride content compared to the HF-OO, HF-SO or LF-PO diet. In the intestine, the HF-PO diet reduced microbial diversity and increased the Firmicutes/Bacteroidetes ratio. Although this fits a typical obesity profile, our data clearly indicate that an overflow of the HF-PO diet to the distal intestine, rather than obesity itself, is the main trigger for these gut microbiota changes. A HF-PO diet-induced elevation of lipid metabolism-related genes in the distal small intestine confirmed the overflow of palm oil to the distal intestine. Some of these lipid metabolism-related genes were previously already associated with the metabolic syndrome. In conclusion, our data indicate that saturated fat (HF-PO) has a more stimulatory effect on weight gain and hepatic lipid accumulation than unsaturated fat (HF-OO and HF-SO). The overflow of fat to the distal intestine on the HF-PO diet induced changes in gut microbiota composition and mucosal gene expression. We speculate that both are directly or indirectly contributive to the saturated fat-induced development of obesity and hepatic steatosis.
Saturated fat stimulates obesity and hepatic steatosis and affects gut microbiota composition by an enhanced overflow of dietary fat to the distal intestine.
Sex, Specimen part
View SamplesEpithelial 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 SamplesThis SuperSeries is composed of the SubSeries listed below.
Dietary haem stimulates epithelial cell turnover by downregulating feedback inhibitors of proliferation in murine colon.
Sex, Age, Specimen part, Treatment
View SamplesWe compared Agilent custom made expression microarrays with Illumina deep sequencing for RNA analysis of zebrafish embryos 5 days post fertilization, showing as expected a high degree of correlation of expression of a common set of 15,927 genes for untreated fish. The transcriptomes were also compared for fish injected in the yolk with Mycobacterium marinum Overall design: This RNA deep sequencing study was designed to determine the gene expression profile of zebrafish embryos 5 days post fertilization. We also have compared expression with embryos that were injected with Mycobacterium marinum in the yolk at 2 hours post fertilization. After injections embryos were transferred into fresh egg water and incubated at 28°C. 150 embryos of mock-injected embryos or 200 embryos injected with 12 CFU bacteria were snap-frozen in liquid nitrogen, and total RNA was isolated using TRIZOL reagent.
Analysis of RNAseq datasets from a comparative infectious disease zebrafish model using GeneTiles bioinformatics.
No sample metadata fields
View SamplesMamamlian cardiogenesis occurs through the development of discreate populations of first and second heart field progenitors. We have used a dual transgenic color reproter system to isolate purified populations of these progenitors.
Generation of functional ventricular heart muscle from mouse ventricular progenitor cells.
No sample metadata fields
View SamplesRepair of injured muscle involves repair of injured myofibers through the involvement of dysferlin and its interacting partners, including annexin. Studies with mice and patients have established that dysferlin deficit leads to chronic inflammation and adipogenic replacement of the diseased muscle. However, longitudinal analysis of annexin deficit on muscle pathology and function is lacking. Here we show that unlike annexin A1, but similar to dysferlin, lack of annexin A2 (AnxA2) causes poor myofiber repair and progressive weakening with age. However, unlike dysferlin-deficient muscle, AnxA2-deficient muscles do not exhibit chronic inflammation or adipogenic replacement. Deletion of AnxA2 in dysferlin deficient mice reduces inflammation, adipogenic replacement, and loss in muscle function caused by dysferlin deficit. These results show that: a) AnxA2 facilitates myofiber repair, b) chronic inflammation and adipogenic replacement of dysferlinopathic muscle requires AnxA2, and c) inhibiting AnxA2-mediated inflammation is a novel therapeutic avenue for dysferlinopathy.
Annexin A2 links poor myofiber repair with inflammation and adipogenic replacement of the injured muscle.
Age, Specimen part
View SamplesEnhanced prenatal fatty streak formation in human fetuses has been associated with maternal hypercholesterolemia. However, the possible roles of maternal genetic background and in utero environment on development of atherosclerosis in adult life have not been unraveled. We generated genetically identical heterozygous apoE-deficient mice offspring with a different maternal background to study the intrauterine effect of maternal genotype and associated hypercholesterolemia on the developing vascular system. As read out for increased atherosclerosis development in adult life, a constrictive collar was placed around the carotid artery to induce lesion formation. A significant increase in endothelial cell activation and damage was detected in the carotid arteries of heterozygous apoE-deficient fetuses with apoE-deficient mothers compared with offspring from wild type mothers, but no fatty streak formation was observed. Postnatally, all carotid arteries revealed normal morphology. In adult offspring with maternal apoE-deficiency, the constrictive collar resulted in severe lesion (9/10) development compared with no to only minor lesions (2/10) in offspring of wild type mothers. Microarray analysis showed no effect of maternal apoE-deficiency on gene expression in adult offspring. We conclude that maternal apoE-deficiency not only affects fetal arteries, but also increases the susceptibility for development of collar-induced atherosclerosis in adult life.
Intrauterine exposure to maternal atherosclerotic risk factors increases the susceptibility to atherosclerosis in adult life.
No sample metadata fields
View SamplesGlucocorticoids control expression of a large number of genes after binding to the glucocorticoid receptor (GR). Transcription may be regulated either by binding of the GR dimer to DNA regulatory elements or by protein-protein interactions of GR monomers with other transcription factors. Although the type of regulation for a number of individual target genes is known, the relative contribution of both mechanisms to the regulation of the entire transcriptional program remains elusive.
Prednisolone-induced differential gene expression in mouse liver carrying wild type or a dimerization-defective glucocorticoid receptor.
Sex, Specimen part
View SamplesBone marrow hematopoietic stem cells (HSCs) are crucial to maintain lifelong production of all blood cells. Although HSCs divide infrequently, it is thought that the entire HSC pool turns over every few weeks, suggesting that HSCs regularly enter and exit cell cycle. Here, we combine flow cytometry with label-retaining assays (BrdU and histone H2B-GFP) to identify a population of dormant mouse HSCs (d-HSCs) within the lin(-)Sca1+cKit+CD150+CD48(-)CD34(-) population. Computational modeling suggests that d-HSCs divide about every 145 days, or five times per lifetime. d-HSCs harbor the vast majority of multilineage long-term self-renewal activity. While they form a silent reservoir of the most potent HSCs during homeostasis, they are efficiently activated to self-renew in response to bone marrow injury or G-CSF stimulation. After re-establishment of homeostasis, activated HSCs return to dormancy, suggesting that HSCs are not stochastically entering the cell cycle but reversibly switch from dormancy to self-renewal under conditions of hematopoietic stress
Hematopoietic stem cells reversibly switch from dormancy to self-renewal during homeostasis and repair.
Specimen part, Time
View Samples