Continuous contact with self-major histocompatibility complex ligands is essential for the survival of naive CD4 T cells. We have previously shown that the resulting tonic TCR signaling also influences their fate upon activation by increasing their ability to differentiate into induced regulatory T cells. To decipher the molecular mechanisms governing this process, microarray data comparing highly (Ly-6C-) and lowly (Ly-6C+) Self-reactive naive CD4 T cells were obtained.
Calcium-mediated shaping of naive CD4 T-cell phenotype and function.
Specimen part
View SamplesBiallelic inactivating mutations of the transcription factor 1 gene (TCF1), encoding hepatocyte nuclear factor 1a (HNF1a), were identified in 50% of hepatocellular adenomas (HCA) phenotypically characterized by a striking steatosis. To understand the molecular basis of this aberrant lipid storage, we performed a microarray transcriptome analysis validated by quantitative RT-PCR, western-blotting and lipid profiling. In mutated HCA, we showed a repression of gluconeogenesis coordinated with an activation of glycolysis, citrate shuttle and fatty acid synthesis predicting elevated rates of lipogenesis. Moreover, the strong dowregulation of L-FABP suggests that impaired fatty acid trafficking may also contribute to the fatty phenotype. In addition, transcriptional profile analysis of the observed deregulated genes in non-HNF1a-mutated HCA as well as in non-tumor livers allowed us to define a specific signature of the HNF1a-mutated HCA. In theses tumors, lipid composition was dramatically modified according to the transcriptional deregulations identified in the fatty acid synthetic pathway. Surprisingly, lipogenesis activation did not operate through SREBP-1 and ChREBP that were repressed. We conclude that steatosis in HNF1a-mutated HCA results mainly from an aberrant promotion of lipogenesis that is linked to HNF1a inactivation and that is independent of both SREBP-1 and ChREBP activation. Finally, our findings have potential clinical implications since lipogenesis can be efficiently inhibited by targeted therapies.
HNF1alpha inactivation promotes lipogenesis in human hepatocellular adenoma independently of SREBP-1 and carbohydrate-response element-binding protein (ChREBP) activation.
Sex, Specimen part, Disease
View SamplesFocal nodular hyperplasias (FNHs) are benign liver lesions considered to be a hyperplastic response to increased blood flow in otherwise normal liver. In contrast, FNH-like nodules occur in cirrhotic liver but share similar histopathological features. To better understand the pathophysiology of FNH, we performed a transcriptomic analysis. Methods: Affymetrix and cDNA microarrays were used to compare gene expression in eight FNHs with that in tissue from six normal livers. Selected genes were validated with quantitative RT-PCR in 70 benign liver tumors including adenomas and cirrhotic and FNH-like lesions. Results: Among the deregulated genes in FNHs, 19 were physiologically zonated in the normal liver lobule. All six periveinous genes were up-regulated in FNH, whereas 13 genes normally expressed in the periportal area were down-regulated. Immunohistochemistry revealed that glutamine synthetase was markedly overexpressed, forming anastomosed areas usually centered on visible veins. -catenin mRNA was slightly but significantly overexpressed, as were several known -catenin target genes. Moreover, activated hypophosphorylated -catenin protein accumulated in FNH in the absence of activating mutations. These results suggest zonated activation of the -catenin pathway specifically in FNH, whereas the other benign hepatocellular tumors, including FNH-like lesions, demonstrated an entirely different pattern of -catenin expression. Conclusions: In FNH, increased expression of the -catenin pathway was restricted to enlarged periveinous areas, which may explain the slight polyclonal over-proliferation of hepatocytes at the origin of the lesion. FNH-like nodules may have a different pathogenetic origin.
The beta-catenin pathway is activated in focal nodular hyperplasia but not in cirrhotic FNH-like nodules.
Sex, Specimen part, Disease
View SamplesThe liver is frequently challenged by surgery-induced metabolic overload, viruses, or toxins, which induce the formation of reactive oxygen species. To determine the effect of oxidative stress on liver regeneration and to identify the underlying signalling pathways, we studied liver repair in mice lacking the Nrf2 transcription factor. In these animals, expression of several cytoprotective enzymes was reduced in hepatocytes, resulting in oxidative stress. As a consequence, tissue damage was aggravated, and liver regeneration after partial hepatectomy was delayed.
Impaired liver regeneration in Nrf2 knockout mice: role of ROS-mediated insulin/IGF-1 resistance.
Specimen part
View SamplesEpithelial-mesenchymal transition (EMT) has been linked to cancer progression and metastatic propensity. The 4T1 tumor is a clinically relevant model of spontaneous breast cancer metastasis. Here we characterize 4T1-derived cell lines for EMT, in vitro invasiveness and in vivo metastatic ability. Contrary to expectations, the 67NR cells, which form primary tumors but fail to metastasize, express vimentin and N-cadherin, but not E-cadherin. 4T1 cells, however, express E-cadherin, are highly migratory and invasive, and metastasize to multiple sites. The 66cl4 metastatic cells display mixed epithelial and mesenchymal markers, but are less migratory and invasive than 67NR cells. These findings demonstrate that the metastatic ability of breast cancer cells does not correlate with genotypic and phenotypic properties of EMT per se, and suggest that other processes may govern metastatic capability. Gene expression analysis also has not identified differences in EMT markers, but has identified several candidate genes that may influence metastatic ability.
Epithelial-mesenchymal transition (EMT) is not sufficient for spontaneous murine breast cancer metastasis.
Sex, Specimen part
View SamplesABSTRACT:Pregnancy requires a higher functional beta cell mass and this is associated with profound changes in the gene expression profile of pancreatic islets. Taking Tph1 as a sensitive marker for pregnancy-related islet mRNA expression in female mice, we previously identified prolactin receptors and placental lactogen as key signalling molecules. Since beta cells from male mice also express prolactin receptors, the question arose whether male and female islets have the same phenotypic resilience at the mRNA level during pregnancy. We addressed this question in vitro, by using islet tissue culture with placental lactogen and in vivo, by transplanting male or female islets into female acceptor mice. Additionally, the islet mRNA expression of pregnant prolactin receptor deficient mice was compared with that of their pregnant wild-type littermates. When cultured with placental lactogen, or transplanted in female recipients that became pregnant (day 12.5), male islets induced the islet pregnancy gene signature, which we defined as the 12 highest induced genes in non-transplanted female islets at day 12.5 of pregnancy. In addition, serotonin immunoreactivity was also induced in these male transplanted islets at day 12.5 of pregnancy. In order to investigate the importance of prolactin receptors in these mRNA changes we used a prolactin receptor deficient mouse model. For the 12 genes of the signature, which are highly induced in control pregnant mice, no significant induction of mRNA transcripts was found at day 9.5 of pregnancy. Together, our results support the key role of placental lactogen as a circulating factor that can trigger the pregnancy mRNA profile in male and female beta cells.
Prolactin receptors and placental lactogen drive male mouse pancreatic islets to pregnancy-related mRNA changes.
Sex, Specimen part
View SamplesABSTRACT:Pregnancy requires a higher functional beta cell mass and this is associated with profound changes in the gene expression profile of pancreatic islets. Taking Tph1 as a sensitive marker for pregnancy-related islet mRNA expression in female mice, we previously identified prolactin receptors and placental lactogen as key signalling molecules. Since beta cells from male mice also express prolactin receptors, the question arose whether male and female islets have the same phenotypic resilience at the mRNA level during pregnancy. We addressed this question in vitro, by using islet tissue culture with placental lactogen and in vivo, by transplanting male or female islets into female acceptor mice. Additionally, the islet mRNA expression of pregnant prolactin receptor deficient mice was compared with that of their pregnant wild-type littermates. When cultured with placental lactogen, or transplanted in female recipients that became pregnant (day 12.5), male islets induced the islet pregnancy gene signature, which we defined as the 12 highest induced genes in non-transplanted female islets at day 12.5 of pregnancy. In addition, serotonin immunoreactivity was also induced in these male transplanted islets at day 12.5 of pregnancy. In order to investigate the importance of prolactin receptors in these mRNA changes we used a prolactin receptor deficient mouse model. For the 12 genes of the signature, which are highly induced in control pregnant mice, no significant induction of mRNA transcripts was found at day 9.5 of pregnancy. Together, our results support the key role of placental lactogen as a circulating factor that can trigger the pregnancy mRNA profile in male and female beta cells.
Prolactin receptors and placental lactogen drive male mouse pancreatic islets to pregnancy-related mRNA changes.
Specimen part
View SamplesAsthma is a heterogeneous disease requiring understandings at molecular level that characterizes subgroups of patients with specific biomarkers to faciliate the development of targeted thearpies.
T-helper cell type 2 (Th2) and non-Th2 molecular phenotypes of asthma using sputum transcriptomics in U-BIOPRED.
Sex, Age
View SamplesTranscriptome analysis was performed from human U87 glioblastoma cell clones: U87 IRE1.NCK DN (U87dn, IRE1 dominant negative) and U87 control (U87ctrl, empty plasmid). Cells were grown in DMEM supplemented with 10% FBS and glutamine for 16 hours in culture prior mRNA isolation and analyses
Inositol-requiring enzyme 1alpha is a key regulator of angiogenesis and invasion in malignant glioma.
Cell line
View SamplesSevere asthma is a collection of disease entities with varying pathophysiological characteristics (7) that result in symptoms of cough, wheeze and breathlessness, with frequent exacerbations. To address the problem of phenotypic difference and heterogeneity, the Unbiased Biomarkers for the Prediction of Respiratory Disease Outcomes (U-BIOPRED) project was set up as a public-private partnership within the framework of the Innovative Medicines Initiative (IMI), engaging academia, the pharmaceutical industry and patient groups. The goal of this investigation was to identify transcript fingerprints in whole blood that characterize patients with severe asthma and to determine whether subgroups of severe asthmatics can be identified. Furthermore, we were interested in elucidating the biological pathways that showed differences between subgroups.
A Severe Asthma Disease Signature from Gene Expression Profiling of Peripheral Blood from U-BIOPRED Cohorts.
Sex, Specimen part, Race
View Samples