The Hippo pathway directs cell differentiation during organogenesis, in part by restricting proliferation. How Hippo signaling maintains a proliferation-differentiation balance in developing tissues and its underlying molecular targets are poorly understood. Our study shows that Hippo suppresses NF?B signaling in pancreatic progenitors to permit cell differentiation and developmental progression. We found that pancreas-specific Lats1/2 kinase deletion (Lats1/2PanKO) from mouse progenitor epithelia results in failure to differentiate 3 key pancreatic lineages: acinar, ductal, and endocrine. We performed an unbiased transcriptome analysis to query the differentiation defects in Lats1/2PanKO. This analysis revealed increased NF?B activator expression, including the pantetheinase Vanin1 (Vnn1). Through in vivo and ex vivo studies, we show that VNN1 activates a detrimental cascade of processes in Lats1/2PanKO epithelium, whereby 1) NF?B activation and 2) initiation of epithelial-to-mesenchymal transition (EMT) together override normal differentiation. We show that exogenous stimulation of VNN1 or NF?B can also trigger this cascade in WT pancreatic progenitors. These findings show that pancreas development requires active suppression of NF?B by LATS1/2 kinases to restrain a cell-autonomous transcriptional program and thereby allow for differentiation. Overall design: RNA-Seq comparing total RNA from 5 WT samples and 3 Lats1/2-deficient pancreas samples at E11.0.
LATS1/2 suppress NFκB and aberrant EMT initiation to permit pancreatic progenitor differentiation.
Cell line, Subject
View SamplesSpinocerebellar ataxia type 2 (SCA2) is a neurodegenerative disorder, which is caused by an unstable CAG-repeat expansion in the SCA2 gene, that encodes a polyglutamine tract (polyQ-tract) expansion in ataxin-2 protein (ATXN2). The RNA-binding protein ATXN2 interacts with the poly(A)-binding protein PABPC1, localizing to ribosomes at the rough endoplasmic reticulum or to polysomes. Under cell stress ATXN2 and PABPC1 show redistribution to stress granules where mRNAs are kept away from translation and from degradation. It is unknown whether ATXN2 associates preferentially with specific mRNAs or how it modulates their processing. Here, we investigated Atxn2 knock-out (Atxn2-/-) mouse liver, cerebellum and midbrain regarding their RNA profile, employing oligonucleotide microarrays for screening and RNA deep sequencing for validation. Modest ~1.4-fold upregulations were observed for the level of many mRNAs encoding ribosomal proteins and other translation pathway factors. Quantitative reverse transcriptase PCR and immunoblots in liver tissue confirmed these effects and demonstrated an inverse correlation also with PABPC1 mRNA and protein. ATXN2 deficiency also enhanced phosphorylation of the ribosomal protein S6, while impairing the global protein synthesis rate, suggesting a block between the enhanced translation drive and the impaired execution. Furthermore, ATXN2 overexpression and deficiency retarded cell cycle progression. ATXN2 mRNA levels showed a delayed phasic twofold increase under amino acid and serum starvation, similar to ATXN3, but different from motor neuron disease genes MAPT and SQSTM1. ATXN2 mRNA levels depended particularly on mTOR signalling. Altogether the data implicate ATXN2 in the adaptation of mRNA translation and cell growth to nutrient availability and stress.
Genetic ablation of ataxin-2 increases several global translation factors in their transcript abundance but decreases translation rate.
Age, Specimen part
View SamplesFiltered selection coupled with support vector machines generate functionally relevant prediction model for colorectal cancer. In this study, we built a model that uses Support Vector Machine (SVM) to classify cancer and normal samples using Affymetrix exon microarray data obtained from 90 samples of 48 patients diagnosed with CRC. From the 22,011 genes, we selected the 20, 30, 50, 100, 200, 300 and 500 genes most relevant to CRC using the Minimum-RedundancyMaximum-Relevance (mRMR) technique. With these gene sets, an SVM model was designed using four different kernel types (linear, polynomial, radial basis function and sigmoid).
Filtered selection coupled with support vector machines generate a functionally relevant prediction model for colorectal cancer.
Sex, Age, Specimen part, Disease stage
View SamplesThe leaf extract of T. indica had been reported to posses high phenolic content and showed high antioxidant activities. However, scientific data on the molecular mechanisms underlying the beneficial properties of the leaf extract are still lacking. In this study, the effects of the leaf extract on the expression of genes in cultured HepG2 cells were investigated using microarray technology. The leaf extract significantly regulated the expression of genes involved with consequential impact on the coagulation system, cholesterol biosynthesis, xenobiotic metabolism signaling and antimicrobial response.
Investigation into the effects of antioxidant-rich extract of Tamarindus indica leaf on antioxidant enzyme activities, oxidative stress and gene expression profiles in HepG2 cells.
Cell line
View SamplesThe water extract of the leaf of B. racemosa had been reported to posses high phenolic content and showed high antioxidant activities. However, scientific data on the molecular mechanisms underlying the beneficial properties of the leaf extract are still lacking. In this study, the effects of the leaf extract on the expression of genes in cultured HepG2 cells were investigated using microarray technology. The leaf extract significantly regulated the expression of genes involved with consequential impact on the glycolysis, gluconeogenesis and metabolism of xenobiotics.
Protective effects of the extracts of Barringtonia racemosa shoots against oxidative damage in HepG2 cells.
Cell line, Treatment
View SamplesThe molecular mechanisms by which individuals subjected to environmental heat stress either adapt or develop heat-related complications are not well understood. We analysed the changes in blood mononuclear gene expression patterns in human volunteers exposed to an extreme heat in a sauna (temperature of 78 6 C).
A Model of Exposure to Extreme Environmental Heat Uncovers the Human Transcriptome to Heat Stress.
Sex, Age, Specimen part, Treatment, Subject, Time
View SamplesLearn about the transcriptome profiling of zona glomerulosa (ZG), zona fasciculata (ZF) and aldosterone-producing adenomas (APA) in human adrenals
DACH1, a zona glomerulosa selective gene in the human adrenal, activates transforming growth factor-β signaling and suppresses aldosterone secretion.
Specimen part, Disease
View SamplesThe epithelial-mesenchymal transition (EMT), considered essential for metastatic cancer, has been a focus of much research, but important questions remain. Here, we show that silencing or removing H2A.X, a histone H2A variant involved in cellular DNA repair and robust growth, induced mesenchymal-like characteristics including activation of EMT transcription factors, Slug and ZEB1, in HCT116 human colon cancer cells. Ectopic H2A.X re-expression partially reversed these changes; as did silencing Slug and ZEB1. In an experimental metastasis model, the HCT116 parental and H2A.X-null cells exhibited similar metastases levels, but the cells with re-expressed H2A.X exhibited substantially elevated levels. We surmise that H2A.X re-expression led to partial EMT reversal and increased robustness in the HCT116 cells, permitting them to both form tumors and to metastasize. In a human adenocarcinoma panel, H2A.X levels correlated inversely with Slug and ZEB1 levels. Together, these results point to H2A.X as a novel regulator of EMT.
The histone variant H2A.X is a regulator of the epithelial-mesenchymal transition.
Cell line
View SamplesStudies have shown that HIV-infected patients develop neurocognitive disorders characterized by neuronal dysfunction. The lack of productive infection of neurons by HIV suggests that viral and cellular proteins, with neurotoxic activities, released from HIV-1-infected target cells can cause this neuronal deregulation. The viral protein R (Vpr), a protein encoded by HIV-1, has been shown to alter the expression of various important cytokines and inflammatory proteins in infected and uninfected cells; however the mechanisms involved remain unclear. Using a human neuronal cell line, we found that Vpr can be taken up by neurons causing: (i) deregulation of calcium homeostasis, (ii) endoplasmic reticulum-calcium release, (iii) activation of the oxidative stress pathway, (iv) mitochondrial dysfunction and v- synaptic retraction. In search for the cellular factors involved, we performed microRNAs and gene array assays using human neurons (primary cultures or cell line, SH-SY5Y) that we treated with recombinant Vpr proteins. Interestingly, Vpr deregulates the levels of several microRNAs (e.g. miR-34a) and their target genes (e.g. CREB), which could lead to neuronal dysfunctions. Therefore, we conclude that Vpr plays a major role in neuronal dysfunction through deregulating microRNAs and their target genes, a phenomenon that could lead to the development of neurocognitive disorders.
Deregulation of microRNAs by HIV-1 Vpr protein leads to the development of neurocognitive disorders.
Specimen part, Cell line, Treatment
View SamplesRenin, a key component in the regulation of blood pressure in mammals, is produced by the rare and highly specialized juxtaglomerular (JG) cells of the kidney. Although these cells line the media of the glomerular afferent arterioles and share some characteristics with contractile cells, they are filled with lysosome-like organelles where renin is activated and stored for regulated secretion in response to physiological and pathophysiological stimuli. Chronic stimulation of renin release results in a recruitment of new JG cells by the seeming conversion of adjacent smooth muscle cells along the afferent arterioles. Because JG cells rapidly de-differentiate when removed from the kidney, their developmental origin and the mechanism that explains their phenotypic plasticity remain largely unclear. In an effort to overcome this limitation, we have performed RNA expression analysis on four human renin-producing tumors. The most highly expressed genes that were common between the reninomas were subsequently used for in situ hybridization in mouse kidney. Our results add 40 new genes to the list that characterize renin-producing cells and reveal a significant variation in the expression patterns of developing, mature and recruited JG cells. Overall design: RNA-Seq was performed with a HiSeq 2000 on three biopsies of a first reninoma from Paris (Par1B1-B3), one biopsy from a reninoma from Montreal (Mon), two biopsies from a reninoma from Rotterdam (RotB1, B2), and a second reninoma from Paris (Par2) along with a biopsy from adjacent supposedly normal tissue from the same patient (Par2N).
Transcriptome Analysis of Human Reninomas as an Approach to Understanding Juxtaglomerular Cell Biology.
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