EphB receptors regulate the proliferation and positioning of intestinal stem and progenitor cells. In addition, they can act as tumor promoters for adenoma development, but suppress progression to invasive carcinoma. Here we used imatinib to abrogate Abl kinase activity in ApcMin/+ mice and in mice with LGR5+ stem cells genetically targeted for APC. This treatment inhibited the tumor-promoting effects of EphB signaling without attenuating EphB-mediated tumor suppression, demonstrating the role of EphB signaling in intestinal tumor initiation. The investigated treatment regimen extended the lifespan of ApcMin/+ mice, and reduced cell proliferation in cultured slices of adenomas from FAP patients. These findings connect the EphB signaling pathway to the regulation of intestinal adenoma initiation via Abl kinase. Our findings may have clinical implications for pharmacological therapy against adenoma formation and cancer progression in patients predisposed to develop colon cancer.
An EphB-Abl signaling pathway is associated with intestinal tumor initiation and growth.
Specimen part
View SamplesPurpose: Investigate the molecular determinants of retinal regeneration in adult vertebrates by analyzing the gene expression profiles of control and post-lesion retina of adult zebrafish, a system that regenerates following injury. Methods: Gene expression profiles of zebrafish retina and brain were determined with DNA microarray, RT-PCR, and real-time quantitative PCR analyses. Damaged retinas and their corresponding controls were analyzed 2-5 days post-lesion (acute injury condition) or 14 d post-lesion (cell regeneration condition). Results: Expected similarities and differences in the gene expression profile of zebrafish retina and brain were observed, confirming the applicability of the gene expression techniques. Mechanical lesion of retina triggered significant, time-dependent changes in retinal gene expression. The induced transcriptional changes were consistent with cellular phenomena known to occur, in a time-dependent manner, subsequent to retinal lesion, including cell cycle progression, axonal regeneration, and regenerative cytogenesis. Conclusions: The results indicate that retinal regeneration in adult zebrafish involves a complex set of induced, targeted changes in gene transcription, and suggest that these molecular changes underlie the ability of the adult vertebrate retina to regenerate. Keywords: time course; injury response; cellular correlation Control brain and retina (unlesioned); Control and lesioned retina (matched animals, at least n = 8 for each condition).
Gene expression profiles of intact and regenerating zebrafish retina.
Specimen part, Subject, Time
View SamplesWe employed GeneChip analysis to investigate the global gene expression profiles of neutrophils from BM
Neutrophil priming occurs in a sequential manner and can be visualized in living animals by monitoring IL-1β promoter activation.
Specimen part
View SamplesHistone deacetylases (Hdac) remove acetyl groups from proteins, influencing global and specific gene expression. Hdacs control inflammation, as shown by Hdac inhibitor-dependent protection from DSS-induced murine colitis. While tissue-specific Hdac knockouts show redundant and specific functions, little is known of their intestinal epithelial cell (IEC) role. We have shown previously that dual Hdac1/Hdac2 IEC-specific loss disrupts cell proliferation and determination, with decreased secretory cell numbers and altered barrier function. We thus investigated how compound Hdac1/Hdac2 or Hdac2 IEC-specific deficiency alters the inflammatory response. Floxed Hdac1 and Hdac2 and villin-Cre mice were interbred. Compound Hdac1/Hdac2 IEC-deficient mice showed chronic basal inflammation, with increased basal Disease Activity Index (DAI) and deregulated Reg gene colonic expression. DSS-treated dual Hdac1/Hdac2 IEC-deficient mice displayed increased DAI, histological score, intestinal permeability and inflammatory gene expression. In contrast to double knockouts, Hdac2 IEC-specific loss did not affect IEC determination and growth, nor result in chronic inflammation. However, Hdac2 disruption protected against DSS colitis, as shown by decreased DAI, intestinal permeability and caspase-3 cleavage. Hdac2 IEC-specific deficient mice displayed increased expression of IEC gene subsets, such as colonic antimicrobial Reg3b and Reg3g mRNAs, and decreased expression of immune cell function-related genes. Our data show that Hdac1 and Hdac2 are essential IEC homeostasis regulators. IEC-specific Hdac1 and Hdac2 may act as epigenetic sensors and transmitters of environmental cues and regulate IEC-mediated mucosal homeostatic and inflammatory responses. Different levels of IEC Hdac activity may lead to positive or negative outcomes on intestinal homeostasis during inflammation
The acetylome regulators Hdac1 and Hdac2 differently modulate intestinal epithelial cell dependent homeostatic responses in experimental colitis.
Specimen part
View SamplesTo test the regulatory effects of Dmrt5 on gene expression, we designed tetracycline inducible lines of Dmrt5 transgenic mouse ESCs. Overexpression of Dmrt5 was induced upon addition of Doxycycline (Dox). To evaluate the effects of Dmrt5 on gene expression in different stages of in vitro differentiated NPC derived from mouse embryonic stem cells (ESC), we analyzed gene expression profiles at differentiation day 7 and day 9 with or without Dox. The data revealed that overexpression of Dmrt5 in in vitro differentiated neural progenitor cells (NPC) regulates gene expression. Addition of Dox to the medium of the control cell line rtTA did not significantly alter gene expression profile, demonstrating that the observed effects were through induction of Dmrt5, but not simply through Dox.
Doublesex and mab-3-related transcription factor 5 promotes midbrain dopaminergic identity in pluripotent stem cells by enforcing a ventral-medial progenitor fate.
Cell line, Treatment
View SamplesReprogramming of somatic cells is a valuable tool to understand the mechanisms of regaining pluripotency and further opens up the possibility of generating patient-specific pluripotent stem cells. Reprogramming of mouse and human somatic cells into pluripotent stem cells, designated as induced pluripotent stem (iPS) cells, has been possible with the expression of the transcription factor quartet Oct4 (also known as Pou5f1), Sox2, c-Myc, and Klf4. Considering that ectopic expression of c-Myc causes tumourigenicity in offspring and retroviruses themselves can cause insertional mutagenesis, the generation of iPS cells with a minimal number of factors may hasten the clinical application of this approach. Here, we show that adult mouse neural stem cells express higher endogenous levels of Sox2 and c-Myc than embryonic stem cells, and that exogenous Oct4 together with either Klf4 or c-Myc are sufficient to generate iPS cells from neural stem cells. These two-factor (2F) iPS cells are similar to embryonic stem cells at the molecular level, contribute to development of the germ line, and form chimeras. We propose that, in inducing pluripotency, the number of reprogramming factors can be reduced when using somatic cells that endogenously express appropriate levels of complementing factors.
Pluripotent stem cells induced from adult neural stem cells by reprogramming with two factors.
No sample metadata fields
View SamplesThe pathogenic mechanisms of common kidney glomerular diseases, including the vast majority of cases of proteinuria, remain unknown.
Glomerular transcriptome changes associated with lipopolysaccharide-induced proteinuria.
No sample metadata fields
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.
No sample metadata fields
View SamplesTo investigate the functional properties of Ly6G+ DC, we employed GeneChip analysis to compare the gene expression profiles between Ly6G+ DC and Ly6C- DC.
Neutrophil differentiation into a unique hybrid population exhibiting dual phenotype and functionality of neutrophils and dendritic cells.
Specimen part
View SamplesThe blood-brain barrier (BBB) consists of specific physical barriers, enzymes and transporters, which together maintain the necessary extracellular environment of the central nervous system (CNS). The main physical barrier is found in the CNS endothelial cell, and depends on continuous complexes of tight junctions combined with reduced vesicular transport. Other possible constituents of the BBB include extracellular matrix, astrocytes and pericytes, but the relative contribution of these different components to the BBB remains largely unknown. Here we demonstrate a direct role of pericytes at the BBB in vivo. Using a set of adult viable pericyte-deficient mouse mutants we show that pericyte deficiency increases the permeability of the BBB to water and a range of low-molecular-mass and high-molecular-mass tracers. The increased permeability occurs by endothelial transcytosis, a process that is rapidly arrested by the drug imatinib. Furthermore, we show that pericytes function at the BBB in at least two ways: by regulating BBB-specific gene expression patterns in endothelial cells, and by inducing polarization of astrocyte end-feet surrounding CNS blood vessels. Our results indicate a novel and critical role for pericytes in the integration of endothelial and astrocyte functions at the neurovascular unit, and in the regulation of the BBB.
Pericytes regulate the blood-brain barrier.
Sex, Age, Specimen part
View Samples