There is increasing appreciation for sexually dimorphic effects, but the molecular mechanisms underlying these effects are only partially understood. In the present study, we explored transcriptomics and epigenetic differences in the small intestine and colon of prepubescent male and female mice. In addition, the microbiota composition of the colonic luminal content has been examined. At postnatal day 14, male and female C57BL/6 mice were sacrificed and the small intestine, colon and content of luminal colon were isolated. Gene expression of both segments of the intestine was analysed by microarray analysis. DNA methylation of the promoter regions of selected sexually dimorphic genes was examined by pyrosequencing. Composition of the microbiota was explored by deep sequencing. Sexually dimorphic genes were observed in both segments of the intestine of 2-week-old mouse pups, with a stronger effect in the small intestine. Amongst the total of 349 genes displaying a sexually dimorphic effect in the small intestine and/or colon, several candidates exhibited a previously established function in the intestine (i.e. Nts, Nucb2, Alox5ap and Retnl). In addition, differential expression of genes linked to intestinal bowel disease (i.e. Ccr3, Ccl11 and Tnfr) and colorectal cancer development (i.e. Wt1 and Mmp25) was observed between males and females. Amongst the genes displaying significant sexually dimorphic expression, nine genes were histone-modifying enzymes, suggesting that epigenetic mechanisms might be a potential underlying regulatory mechanism. However, our results reveal no significant changes in DNA methylation of analysed CpGs within the selected differentially expressed genes. With respect to the bacterial community composition in the colon, a dominant effect of litter origin was found but no significant sex effect was detected. However, a sex effect on the dominance of specific taxa was observed. This study reveals molecular dissimilarities between males and females in the small intestine and colon of prepubescent mice, which might underlie differences in physiological functioning and in disease predisposition in the two sexes.
Sexually dimorphic characteristics of the small intestine and colon of prepubescent C57BL/6 mice.
Sex, Age, Specimen part
View SamplesDuring the last few decades, the long-lasting consequences of nutritional programming during the early phase of life have become increasingly evident, but the effects of maternal nutrition on the developing intestine are currently still relatively underexplored. In this study, we investigated in mice the effects of a maternal Western-style (WS) high fat/cholesterol diet, given during the perinatal period, on gene expression and microbiota composition of two-week-old offspring. Microarray analysis revealed that a perinatal WS diet caused significant changes in gene expression in the small intestine and colon of the suckling offspring. A strong sexually dimorphic effect was observed in the affected genes. However, pathway analysis of the differentially expressed genes displayed that in both sexes metabolic and immune functions were strongly affected. Integration of the microbiota and gene expression data applying a multivariate correlation analyses revealed that Bacteroidaceae, Porphyromonadaceae and Lachnospiraceae were the bacterial families that most strongly correlated with gene expression in the colon and not with the bacterial families displaying the most pronounced change due to perinatal exposure to a WS diet. Amongst the genes demonstrating a strong correlation with one or more bacterial families were genes of key importance for intestinal development or functioning (i.e., Pitx2 and Ace2). In conclusion, our data demonstrate a strong programming effect of a maternal WS diet on the development of the intestine in the offspring.
Maternal exposure to a Western-style diet causes differences in intestinal microbiota composition and gene expression of suckling mouse pups.
Sex, Age, Specimen part
View SamplesWe analyzed the genome-wide expression by RNA-seq of a yeast strain that expresses Cas9d and a guideRNA targeted to the GAL10 locus (called +116), which inhibits GAL10 ncRNA expression from the antisense strand. We compared this strain to a strain expressing a scrambled guideRNA. The goal was to examine the effects of ncRNA inhibition and to examine if CRISPR inhibition of gene expression has off-target effects. We find that CRISPR-mediated inhibtion of GAL10 ncRNA only significantly changes expression of transcripts at the GAL1-10 locus, showing that CRISPR is highly specific, and that GAL10 ncRNA only control genes at the GAL locus. Overall design: RNA-seq of 2 strains with CRISPR scrambled and 2 strains with CRISPR +116, the latter of which inhibits GAL10 ncRNA
Single-Molecule Imaging Reveals a Switch between Spurious and Functional ncRNA Transcription.
Cell line, Subject
View SamplesTreatment induced senescence (TIS) is a terminal cell cycle arrest program, increasingly recognized as a tumor suppressor mechanism complementing apoptosis in response to standard chemotherapy regimens. In particular cells with blocked apoptotic pathways rely on senescence as the only remaining failsafe mechanism to keep the neoplastic growth in check. However, little is known about biological properties, long-term fate of senescent tumor cells and their impact on the microenvironment.
Opposing roles of NF-κB in anti-cancer treatment outcome unveiled by cross-species investigations.
No sample metadata fields
View SamplesDiffuse large B-cell lymphoma (DLBCL) represents a heterogeneous diagnostic category with distinct molecular subtypes that can be defined by gene expression profiling. However, even within these defined subtypes, heterogeneity prevails. To further elucidate the pathogenesis of these entities, we determined the expression of the tumor suppressor phosphatase and tensin homolog (PTEN) in 248 primary DLBCL patient samples. These analyses revealed that loss of PTEN was detectable in 55% of germinal center B-cell-like (GCB) DLBCLs, whereas this abnormality was found in only 14% of non-GCB DLBCL patient samples. In GCB DLBCL, the PTEN status was inversely correlated with activation of the oncogenic PI3K/ protein kinase B (AKT) pathway in both DLBCL cell lines and primary patient samples. Re-expression of PTEN induced cytotoxicity in PTEN-deficient GCB DLBCL cell line models by inhibiting PI3K/AKT signaling, indicating an addiction to this pathway in this subset of GCB DLBCLs. PI3K/AKT inhibition induced down-regulation of the transcription factor MYC. Re-expression of MYC rescued GCB DLBCL cells from PTEN-induced toxicity, identifying a regulatory mechanism of MYC expression in DLBCL. Finally, pharmacologic PI3K inhibition resulted in toxicity selectively in PTEN-deficient GCB DLBCL lines. Collectively, our results indicate that PTEN loss defines a PI3K/ AKT-dependent GCB DLBCL subtype that is addicted to PI3K and MYC signaling and suggest that pharmacologic inhibition of PI3K might represent a promising therapeutic approach in these lymphomas.
PTEN loss defines a PI3K/AKT pathway-dependent germinal center subtype of diffuse large B-cell lymphoma.
Sex, Disease, Cell line, Treatment
View SamplesIn many mammals, halogenated aromatic hydrocarbon (HAH) exposure causes wasting syndrome, defined as lethal weight loss as a result of severe and persistent hypophagia. The most potent HAH in causing wasting is 2,3,7,8-tetrachlorodibenzo--dioxin (TCDD), which exerts its toxic effects through the aryl hydrocarbon receptor (AHR) a transcription factor. Because TCDD toxicity is thought to predominantly arise from dysregulation of AHR-transcribed genes, we hypothesized that wasting syndrome is due to TCDD-induced dysregulation of genes involved in regulation of food-intake. We therefore focused on the hypothalamus, as it is the regulatory center of food-intake and energy balance in the central nervous system. We profiled mRNA abundance in hypothalamic tissue from two rat strains with widely differing sensitivities to wasting syndrome: TCDD-sensitive Long-Evans rats and TCDD-resistant Han/Wistar rats, 23 hours after exposure to TCDD (100 g/kg) or corn oil vehicle. We found that TCDD exposure caused minimal transcriptional dysregulation effects in the hypothalamus, with only 6 genes changed in Long-Evans rats and 15 genes in Han/Wistar rats. Two of the most dysregulated genes were Cyp1a1 and Nqo1, which are induced by TCDD across a wide range of tissues and are considered sensitive markers of TCDD exposure. The minimal response of the hypothalamic transcriptome to a lethal dose of TCDD at an early time-point suggests that the hypothalamus is not the predominant site of initial events leading to hypophagia and associated wasting. TCDD may affect feeding behaviour via events upstream or downstream of the hypothalamus, and further work is required to evaluate this at the level of individual hypothalamic nuclei and subregions.
Transcriptional profiling of rat hypothalamus response to 2,3,7,8-tetrachlorodibenzo-ρ-dioxin.
Sex
View SamplesIn T-cell acute lymphoblastic leukemia (T-ALL) NOTCH 1 receptors are frequently mutated. This leads to aberrantly high Notch signaling, but how this translates into deregulated cell cycle control and the transformed cell type is poorly understood. In this report, we analyze downstream responses resulting from the high level of NOTCH 1 signaling in T-ALL. Notch activity, measured immediately downstream of the NOTCH 1 receptor, is high, but expression of the canonical downstream Notch response genes HES 1 and HEY 2 is low both in primary cells from T-ALL patients and in T-ALL cell lines. This suggests that other immediate Notch downstream genes are activated, and we found that Notch signaling controls the levels of expression of the E3 ubiquitin ligase SKP2 and its target protein p27Kip1. We show that in T-ALL cell lines, recruitment of NOTCH 1 ICD to the SKP2 promoter was accompanied by high SKP2 and low p27Kip1 protein levels were low. In contrast, pharmacologically blocking Notch signaling reversed this picture and led to loss of NOTCH 1 ICD occupancy of the SKP2 promoter, decreased SKP2 and increased p27Kip1 expression. T-ALL cells show a rapid G1-S cell cycle transition, while blocked Notch signaling resulted in G0/G1 cell cycle arrest, also observed by transfection of p27Kip1 or, to a smaller extent, a dominant negative SKP2 allele. Collectively, our data suggest that the aberrantly high Notch signaling in T-ALL maintains SKP2 at a high level and reduces p27Kip1, which leads to more rapid cell cycle progression.
Notch signaling induces SKP2 expression and promotes reduction of p27Kip1 in T-cell acute lymphoblastic leukemia cell lines.
No sample metadata fields
View SamplesRodents exposed to the environmental contaminant, TCDD, suffer from a number of acute and chronic toxicities, including lethality and a wasting syndrome. Hypothesizing that the wasting syndrome may be caused by changes in adipose tissue -- either in its hormonal regulation or in homeostatic effects -- we profiled the transcriptional response of rat white adipose to TCDD. We employed two separate rat strains: the Long-Evans strain is sensitive to TCDD toxicities while the Han/Wistar strain is over four orders of magnitude more resistant. One day after TCDD exposure few genes were altered in either strain, but after four days a modest number of transcriptional alterations were observed. Strikingly, TCDD had far fewer effects than did a feed-restriction protocol intended to mimic the wasting syndrome itself. Notably several classic TCDD-responsive genes were modulated at all time-points, including Cyp1a1, Cyp1b1, and Nqo1. We therefore concluded that rat adipose tissue is unlikely to be the primary driver of the wasting syndrome, and that another tissue is likely involved.
Transcriptional profiling of rat white adipose tissue response to 2,3,7,8-tetrachlorodibenzo-ρ-dioxin.
Sex
View SamplesPluripotency, the capacity of embryo-derived stem cells to generate all tissues in the organism, can be induced in somatic cells by nuclear transfer into oocyte, fusion with embryonic stem cells, and for male germ cells by cell culture alone. Recently, murine fibroblasts have been reprogrammed directly to pluripotency by ectopic expression of four transcription factors (Oct4, Sox2, Klf4, and Myc) to yield induced Pluripotent Stem (iPS) cells. Using the same four factors, we have derived iPS cells from human embryonic stem cell-derived fibroblasts, primary human fetal cells, and diverse cells of neonatal and adult human origin. The human iPS cells manifest the colony morphology, gene expression patterns, and epigenetic characteristics of human Embryonic Stem (hES) cells, and form well-differentiated teratomas in immune-deficient mice. These data demonstrate that defined factors can reprogram human cells to pluripotency, and establish a method whereby patient-specific cells might be established in culture.
Reprogramming of human somatic cells to pluripotency with defined factors.
No sample metadata fields
View SamplesVascular smooth muscle cells (VSMC) are important for contraction, blood flow distribution and regulation of blood vessel diameter, but to what extent they contribute to the integrity of blood vessels and blood-brain barrier function is less well understood. In this report, we explored the impact of the progressive loss of VSMC in the Notch3-/- mouse on blood vessel integrity in the central nervous system
Notch3 is necessary for blood vessel integrity in the central nervous system.
Age, Specimen part
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