Microarray gene expression experiments to identify differentially expressed genes and pathways in Jag1 conditional/null livers reveal up-regulation of many genes related to fibrosis and ECM interactions.
Microarray data reveal relationship between Jag1 and Ddr1 in mouse liver.
Age, Specimen part
View SamplesNumerous studies have established a critical role for BMP signaling in skeletal development. In the developing axial skeleton, sequential SHH and BMP signals are required for specification of a chondrogenic fate in somitic tissue. A similar paradigm is thought to operate in the limb, but the signals involved are unclear. To investigate the nature of these signals we examined BMP action in mesenchymal populations derived from the early murine limb bud (~ E10.5). These populations exhibited a graded response to BMPs, in which early limb mesenchymal (EL) cells (from the distal hind limb) displayed an anti-chondrogenic response, whereas BMPs promoted chondrogenesis in older cell populations. To better understand the molecular basis of disparate BMP action in these various populations, gene expression profiling with Affymetrix microarrays was employed to identify BMP-regulated genes. These analyses showed that BMPs induced a distinct gene expression pattern in the EL cultures versus later mesenchymal limb populations (IM and LT).
Regulation of BMP-dependent chondrogenesis in early limb mesenchyme by TGFbeta signals.
Specimen part
View SamplesInnate immune pattern recognition receptors play critical roles in pathogen detection and initiation of antimicrobial responses. We and others have previously demonstrated the importance of the beta-glucan receptor Dectin-1 in the recognition of pathogenic fungi by macrophages and dendritic cells, and have elucidated some of the mechanisms by which Dectin-1 signals to coordinate the antifungal response. While Dectin-1 signals alone are sufficient to trigger phagocytosis and Src-Syk-mediated induction of antimicrobial reactive oxygen species, collaboration with Toll-like receptor (TLR)2 signaling enhances NF-kB activation and regulates cytokine production. In this study we demonstrate that Dectin-1 signaling can also directly modulate gene expression via activation of nuclear transcription of activated T cells (NFAT) transcription factors. Dectin-1 ligation by zymosan particles or live Candida albicans yeast triggers NFAT activation in macrophages and dendritic cells. Dectin-1-triggered NFAT activation plays a role in the induction of Egr2 and Egr3 transcription factors, and cyclooxygenase 2 (Cox-2). Furthermore, we show that NFAT activation regulates IL-2, IL-10 and IL-12 p70 production by zymosan-stimulated dendritic cells. These data establish NFAT activation in myeloid cells as a novel mechanism of regulation of the innate antimicrobial response.
Dectin-1 stimulation by Candida albicans yeast or zymosan triggers NFAT activation in macrophages and dendritic cells.
No sample metadata fields
View SamplesPrimary micromass cultures derived from 11.5 day old mouse embryo limb buds were cultured for 15 days in differentiating conditions (beta-glycerophosphate and ascorbic acid). Total RNA from differentiating chondrocytes was isolated every three days i.e. days 3,6,9,12 and 15 and hybridized to MOE430A chips. Objective: Gain a view of the temporal gene expression changes occuring during chondrocyte differentiation.
Microarray analyses of gene expression during chondrocyte differentiation identifies novel regulators of hypertrophy.
No sample metadata fields
View SamplesBackground: Glucocorticoids (GCs) are widely used anti-inflammatory drugs. While useful in clinical practice, patients taking GCs often suffer from skeletal side effects including growth retardation and decreased bone quality in adults. On a physiological level, GCs have been implicated in the regulation of chondrogenesis and osteoblast differentiation, as well as maintaining homeostasis in cartilage and bone. We identified the glucocorticoid receptor (GR) as a potential regulator of chondrocyte hypertrophy in a microarray screen of primary limb bud mesenchyme micromass cultures. Some targets of GC regulation in chondrogenesis are known, but the global effects of pharmacological GC doses on chondrocyte gene expression have not been comprehensively evaluated.
Expression profiling of Dexamethasone-treated primary chondrocytes identifies targets of glucocorticoid signalling in endochondral bone development.
No sample metadata fields
View SamplesCell body and pseudopod RNA are differentially regulated during the migration of the metastatic cancer cells.We wanted to identify the RNA which are upregulated in the pseudopodial (PS) fraction as compared to cell body fraction (CB).
Pseudopodial actin dynamics control epithelial-mesenchymal transition in metastatic cancer cells.
Cell line
View SamplesA variety of cell cultures models and in vivo approaches have been used to study gene expression during chondrocyte differentiation. The extent to which the in vitro models reflect bona fide gene regulation in the growth plate has not been quantified. In addition, studies that evaluate global gene expression changes among different growth plate zones are limited. To address these issues, we completed a microarray screen of three growth plate zones derived from manually segmented embryonic mouse tibiae. Classification of genes differentially expressed between each respective growth plate zone, functional categorization as well as characterization of gene expression patterns, cytogenetic loci, signaling pathways and functional motifs confirmed documented data and pointed to novel aspects of chondrocyte differentiation. Parallel comparisons of the microdissected tibiae data set to our previously completed micromass culture screen further corroborated the suitability of micromass cultures for modeling gene expression in chondrocyte development. The micromass culture system demonstrated striking similarities to the in vivo microdissected tibiae screen; however, the micromass system was unable to accurately distinguish gene expression differences in the hypertrophic and mineralized zones of the growth plate. These studies will allow us to better understand zone-specific gene expression patterns in the growth plate. Ultimately, this work will help define both the genomic context in which genes are expressed in the long bones and the extent to which the micromass culture system is able to recapitulate chondrocyte development in endochondral ossification.
Genome-wide analyses of gene expression during mouse endochondral ossification.
No sample metadata fields
View SamplesExtracellular matrix interactions play essential roles in normal physiology and many pathological processes. Here, we report a novel screening platform capable of measuring phenotypic responses to combinations of ECM molecules. While the importance of ECM interactions in metastasis is well documented, systematic approaches to identify their roles in distinct stages of tumorigenesis have not been described. Using a genetic mouse model of lung adenocarcinoma, we measured the ECM-dependent adhesion of tumor-derived cells. Hierarchical clustering of adhesion profiles generated using this platform differentially segregated metastatic cell lines from primary tumor lines. Furthermore, we uncovered that metastatic cells selectively associate with fibronectin when in combination with galectin-3, galectin-8, or laminin. These interactions appear to be mediated in part by 31 integrin both in vitro and in vivo. We show that these galectins also correlate with human disease at both a transcriptional and histological level. Thus, our in vitro platform allowed us to interrogate the interactions of metastatic cells with their surrounding environment, and identified ECM and integrin interactions that could lead to therapeutic targets for metastasis prevention.
A combinatorial extracellular matrix platform identifies cell-extracellular matrix interactions that correlate with metastasis.
Specimen part
View SamplesPublished molecular profiling studies in patients with lymphoma suggested the influence of hypoxia inducible factor-1 alpha (HIF1) targets in prognosis of DLBCL. Yet, the role of hypoxia in hematological malignancies remains unclear. We observed that activation of HIF1 resulted in global translation repression during hypoxic stress in DLBCL. Protein translation efficiency as measured using 35S-labeled methionine incorporation revealed a 50% reduction in translation upon activation of HIF1. Importantly, translation was not completely inhibited and expression of clinically correlated hypoxia targets such as GLUT1, HK2, and CYT-C was found to be refractory to translational repression under hypoxia in DLBCL cells. Notably, hypoxic induction of these genes was not observed in normal primary B-cells. Translational repression was coupled with a decrease in mitochondrial function. Screening of primary DLBCL patient samples revealed that expression of HK2, which encodes for the enzyme hexokinase 2, was significantly correlated with DLBCL phenotype. Genetic knockdown studies demonstrated that HK2 is required for promoting growth of DLBCL under hypoxic stress. Altogether, our findings provide strong support for the direct contribution of HK2 in B-cell lymphoma development and suggest that HK2 is a key metabolic driver of the DLBCL phenotype.ne incorporation revealed a 50% reduction in translation upon activation of HIF1. Importantly, translation was not completely blunted and expression of clinically correlated hypoxia targets such as GLUT1, HK2, and CYT-C was found to be refractory to translational repression under hypoxia in DLBCL cells. Notably, hypoxic induction of these genes was not observed in normal primary B-cells. Translational repression was coupled with decrease in mitochondrial function. Screening of DLBCL patient samples identified that expression of HK2, which encodes for the enzyme hexokinase 2, was significantly correlated with DLBCL phenotype. Genetic knockdown studies show that HK2 is required for promoting growth of DLBCL under hypoxic stress. Altogether, our findings provide more definitive proof of direct contribution of HK2 in development of B-cell lymphoma and suggest that HK2 is a key metabolic driver of DLBCL phenotype.
Role of hypoxia in Diffuse Large B-cell Lymphoma: Metabolic repression and selective translation of HK2 facilitates development of DLBCL.
Cell line, Treatment
View SamplesThe methyltransferase G9a was found to play a role in the disease progression of a murine model of AML.
The methyltransferase G9a regulates HoxA9-dependent transcription in AML.
Cell line
View Samples