Hepatocyte-nuclear-factor-4 (Hnf4) is a transcription factor that controls epithelial cell polarity and maturation during embryogenesis. Hnf4 conditional deletion during post-natal development results in minor consequences on intestinal epithelium integrity but promotes activation of the Wnt/-catenin pathway. Here we show that Hnf4 does not act as a tumor suppressor gene but is crucial to promote gut tumorigenesis in mice. Polyp multiplicity in ApcMin mice that lacks Hnf4 is suppressed in comparison to littermate ApcMin controls. Analysis of microarray gene expression profiles from mice lacking Hnf4 in the intestinal epithelium identifies its novel function in regulating the expression of reactive oxygen species (ROS) detoxifying genes. This role is supported with the demonstration that HNF4 is functionally involved in the protection against spontaneous and 5-fluorouracil chemotherapy-induced production of intracellular ROS in colorectal cancer cell lines. The analysis of a colorectal cancer patient cohort establishes that HNF4 is significantly up-regulated at both gene transcript and protein levels in tumors relative to adjacent benign epithelial resections. Several genes involved in ROS neutralization are also up-regulated in correlation with HNF4 expression. All together, the findings point to the nuclear receptor HNF4 as a potential therapeutic target to eradicate aberrant epithelial cell resistance to ROS production during intestinal tumorigenesis.
Hepatocyte nuclear factor-4alpha promotes gut neoplasia in mice and protects against the production of reactive oxygen species.
Specimen part
View SamplesBackground & Aims: HNF4 is an important transcriptional regulator of hepatocyte and pancreatic function. Hnf4 deletion is embryonically lethal with severe defects in visceral endoderm formation, liver maturation and colon development. However, the precise role of this transcription factor in maintaining homeostasis of the adult intestine remains unclear. Herein, we aimed to elucidate the adult intestinal functions of Hnf4. Methods: A conditional intestinal epithelial Hnf4 knockout mouse was generated. Histological abnormality of the colonic mucosa was assessed by immunodetection and Western. Changes in global gene expression and biological network were analyzed. Results: Hnf4 intestine null mice developed normally until reaching young adulthood. Crypt distortion became apparent in the Hnf4 null colon at 3 months of age followed by focal areas of crypt dropout, increased immune cell infiltrates, crypt hyperplasia and early signs of polyposis later in life. A gene profiling analysis identified cell death and cell cycle related to cancer as the most significant sets of genes altered in the Hnf4 colon null mice. Expression levels of the tight junction proteins claudin 4, 8 and 15 were altered early in the colon epithelium of Hnf4 mutants and correlated with increased barrier permeability to a molecular tracer that does not normally penetrate normal mucosa. Conclusion: These observations support a functional role for Hnf4 in protecting the colonic mucosa against the initiation of the changes resembling inflammatory bowel diseases and polyp formation.
Loss of hepatocyte-nuclear-factor-4alpha affects colonic ion transport and causes chronic inflammation resembling inflammatory bowel disease in mice.
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View SamplesDuchenne Muscular Dystrophy (DMD) is a fatal muscle wasting disorder caused by dystrophin deficiency. Previous work suggested that increased expression of the dystrophin-related protein utrophin in the mdx mouse model of DMD can prevent dystrophic pathophysiology. Physiological tests showed that the transgenic mouse muscle functioned in a way similar to normal muscle. More recently, it has become possible to analyse disease pathways using microarrays, a sensitive method to evaluate the efficacy of a therapeutic approach. We thus examined the gene expression profile of mdx mouse muscle compared to normal mouse muscle and compared the data with that obtained from the transgenic line expressing utrophin. The data confirm that the expression of utrophin in the mdx mouse muscle results in a gene expression profile virtually identical to that seen for the normal mouse. This study confirms that a strategy to up-regulate utrophin is likely to be effective in preventing the disease.
Microarray analysis of mdx mice expressing high levels of utrophin: therapeutic implications for dystrophin deficiency.
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View SamplesThere is much evidence that T cells may be activated via mechanisms which act independently of direct TCR ligation. Despite this, the question of whether such forms of bystander T cell activation occur during immune responses is hotly debated.
Human CD4+ memory T cells are preferential targets for bystander activation and apoptosis.
No sample metadata fields
View SamplesReplicating viruses have broad applications in biomedicine, notably in cancer virotherapy and in the design of attenuated vaccines, however uncontrolled virus replication in vulnerable tissues can give pathology and often restricts the use of potent strains. Increased knowledge of tissue-selective microRNA expression now affords the possibility of engineering replicating viruses that are attenuated at the RNA level in sites of potential pathology, but retain wild type replication activity at sites not expressing the relevant microRNA.
MicroRNA controlled adenovirus mediates anti-cancer efficacy without affecting endogenous microRNA activity.
Sex, Age, Specimen part, Treatment
View SamplesOligodendrocyte precursor cells from postnatal day 10 optic nerve remained in a developmentally immature state in LIF-/- mice. Partial recovery of myelin genes is seen in LIF-/- mice by postnatal day 14 in the optic nerve. Very little difference in myelin genes in the optic nerve is seen by postnatal day 35 (adult).
Leukemia inhibitory factor regulates the timing of oligodendrocyte development and myelination in the postnatal optic nerve.
Sex, Specimen part
View SamplesThe mammalian suprachiasmatic nucleus (SCN) drives daily rhythmic behavior and physiology, yet a detailed understanding of its coordinated transcriptional programmes is lacking. To reveal the true nature of circadian variation in the mammalian SCN transcriptome we combined laser-capture microdissection (LCM) and RNA-Seq over a 24-hour light / dark cycle. We show that 7-times more genes exhibited a classic sinusoidal expression signature than previously observed in the SCN. Another group of 766 genes unexpectedly peaked twice, near both the start and end of the dark phase; this twin-peaking group is significantly enriched for synaptic transmission genes that are crucial for light-induced phase-shifting of the circadian clock. 342 intergenic non-coding RNAs, together with novel exons of annotated protein-coding genes, including Cry1, also show specific circadian expression variation. Overall, our data provide an important chronobiological resource (www.wgpembroke.com/shiny/SCNseq/) and allow us to propose that transcriptional timing in the SCN is gating clock resetting mechanisms. Overall design: Pooled dissected tissue of the suprachiasmatic nucleus from five adult male mice provided one of three replicates for each of six timepoints over a 12:12 light/dark (LD) cycle (ZT2, 6, 10, 14, 18 and 22). Each biological replicate was sequenced over 3 seperate lanes using Illumina HiSeq.
Temporal transcriptomics suggest that twin-peaking genes reset the clock.
Specimen part, Cell line, Subject
View SamplesIn the normal mouse the pituitary gonadotrophins determine development, maturation and physiological regulation of the testis with follicle-stimulating hormone (FSH) activating the Sertoli cell and luteinising hormone (LH) the Leydig cell. To look at the potential interaction of cell types within the testis following hormone stimulation we have investigated the effect of rFSH on testicular gene expression in the hypogonadal (hpg) male mouse. Due to a deletion in the gene encoding gonadotrophin-releasing hormone (GnRH), FSH and LH levels are at the lower limit of detection in the circulation and mice remain in a pre-pubertal state throughout life unless given exogenous hormone.
Effects of FSH on testicular mRNA transcript levels in the hypogonadal mouse.
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View SamplesLow incubation temperature during early development negatively affects survival and related innate immune processes in zebrafish larvae exposed to lipopolysaccharide Overall design: Zebrafish embryos were collected from 28 °C, and divided into three temperature groups (24 °C, 28 °C, 32 °C) for incubation. At the first-feeding stage, larvae from each incubation temperature group were further split into three temperature groups in a full-factorial way for LPS challenge. In total, nine temperature groups (three incubation temperatures x three challenge temperatures) were generated. At 24 h post LPS challenge, mortality of larvae were recorded. Larvae originating from 24 °C incubation temperature group had higher mortality rate than larvae from the other two temperature groups. LPS-treated larvae from three temperature groups, incubation 24 °C x challenge 24 °C, incubation 24 °C x challenge 32 °C, and incubation 32 °C x challenge 24 °C, together with their respective control were chosen for transcriptomic analyses using mRNA sequencing. A total of 722 genes were determined differentially expressed (DEGs) by DESeq2 (adjusted p-value < 0.05) in LPS-challenged larvae compared to control, and 605 of them had a fold change greater than 1.5, including 294 DEGs (144 up-/150 down-regulated) in larvae incubated and challenged with LPS at 24 °C; 33 DEGs (20 up-/13 down-regulated) in larvae incubated at 32 °C and challenged at 24 °C; and 278 DEGs (190 up-/88 down-regulated) in larvae incubated at 24 °C and challenged at 32 °C. Larvae incubated and challenged with LPS at 24 °C had stimulated innate immune response compared to control, while they also showed down-regulated innate immune processes and genes. In larvae incubated at 32 °C and challenged at 24 °C, the innate immune processes were up-regulated in larvae exposed to LPS compared to control, and theses processes were even much stronger (with higher enrichment values) than larvae from incubation and challenge temperature of 24 °C. In larvae incubated at 24 °C and challenged with LPS at 32 °C, limited innate immune response were up-regulated, and additional hypoxia and oxidative processes were observed. Genes annexin A2a, S100 calcium binding protein A10b, and lymphocyte antigen-6, epidermis were identified as promising candidates for LPS recognition and signal transduction.
Low incubation temperature during early development negatively affects survival and related innate immune processes in zebrafish larvae exposed to lipopolysaccharide.
Specimen part, Cell line, Subject
View SamplesOne of the hallmarks in hypertension is a pressure-induced change in endothelial cell phenotype. A cytoskeletal protein zyxin, which was seen to translocate from focal adhesion contacts to the nucleus in response to the increased wall tensionis, mediates the tension-induced endothelial signaling.
Zyxin mediation of stretch-induced gene expression in human endothelial cells.
Specimen part
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