RNA helicases DDX5 and DDX17 are members of a large family of highly conserved proteins involved in gene expression regulation, although their in vivo targets and activities in biological processes like cell differentiation, that requires reprogramming of gene expression programs at multiple levels, are not well characterized. In this report, we uncovered a new mechanism by which DDX5 and DDX17 cooperate with hnRNP H/F splicing factors to define epithelial- and myoblast-specific splicing subprograms. We next observed that downregulation of DDX5 and DDX17 protein expression during epithelial to mesenchymal transdifferentiation and during myogenesis contributes to switching splicing programs during these processes. Remarkably, this downregulation is mediated by the production of microRNAs induced upon differentiation in a DDX5/DDX17-dependent manner. Since DDX5 and DDX17 also function as coregulators of master transcriptional regulators of differentiation, we propose to name these proteins master orchestrators of differentiation, that dynamically orchestrate several layers of gene expression.
RNA helicases DDX5 and DDX17 dynamically orchestrate transcription, miRNA, and splicing programs in cell differentiation.
Specimen part, Cell line
View SamplesDendritic cells (DCs) are the sentinels of the mammalian immune system and they undergo a complex maturation process mediated by activation upon pathogen detection. Recent studies described the analysis of activated DCs by transcriptional profiling, but translation regulation was never taken in account. Therefore, the nature of the mRNAs being translated at various stages of DC activation was determined with the help of translational profiling, which is the sucrose gradient fractionation of polysomal-bound mRNAs combined to microarrays analysis. Total and polysomal-bound mRNA populations were compared in immature (0h) and LPS-stimulated (4h and 16h) human monocyte-derived DCs with the help of Affymetrix microarrays. Biostatistical analysis indicated that 296 mRNA molecules are translationally regulated during DC-activation. The most abundant biological process among the regulated mRNAs was protein biosynthesis, indicating the existence of a negative feedback loop regulating translation. Interestingly, a cluster of 17 ribosomal proteins were part of the regulated mRNAs, indicating that translation may be fine-tuned by particular components of the translational machinery. Our observations highlight the importance of translation regulation during the immune response, and may favour the identification of novel gene clusters or protein networks relevant for immunity. Our study also provides information on the possible absence of correlation between gene expression and real protein production in DCs.
Ribosomal protein mRNAs are translationally-regulated during human dendritic cells activation by LPS.
No sample metadata fields
View SamplesGuanabenz is an FDA approved drug for hypertension. It has been shown also to be an inhibitor of GADD34, the stress-inducible cofactor of PP1. GADD34 has been shown to play a key role in controlling cytokine production in MEFs and dendritic cells.
No associated publication
Sex, Age, Specimen part
View SamplesIn response to inflammatory stimulation, dendritic cells (DCs) have a remarkable pattern of differentiation that exhibits specific mechanisms to control the immune response. Here we show that in response to polyriboinosinic:polyribocytidylic acid (poly I:C), DCs mount a specific transcription program during which the growth arrest and DNA damage-inducible protein 34 (GADD34/MyD116), a phosphatase 1 (PP1) cofactor, is expressed. Together with its constitutively active counterpart CReP, GADD34 promotes an extensive dephosphorylation of the translation initiation factor eIF2-alfa in activated DCs. In turn, dephosphorylation of eIF2-alfa prevents the translation inhibition normally associated with cellular stress or detection of cytoplasmic double-stranded RNA. These observations have important implications in linking pathogen detection with the integrated stress responses molecular machinery. The importance of this regulation for DC function is exemplified by the alteration of IFN-beta production or the induction of caspase-3 cleavage upon inhibition of PP1 activity.
No associated publication
Specimen part
View SamplesIn response to inflammatory stimulation, dendritic cells (DCs) have a remarkable pattern of differentiation (maturation) that exhibits specific mechanisms to control immunity. Here, we show that in response to Lipopolysaccharides (LPS), several microRNAs (miRNAs) are regulated in human monocyte-derived dendritic cells. Among these miRNAs, miR-155 is highly up-regulated during maturation. Using LNA silencing combined to microarray technology, we have identified the Toll-like receptor / interleukin-1 (TLR/IL-1) inflammatory pathway as a general target of miR-155. We further demonstrate that miR-155 directly controls the level of important signal transduction molecules. Our observations suggest, therefore, that in mature human DCs, miR-155 is part of a negative feedback loop, which down-modulates inflammatory cytokine production in response to microbial stimuli.
MicroRNA-155 modulates the interleukin-1 signaling pathway in activated human monocyte-derived dendritic cells.
No sample metadata fields
View SamplesParadoxical sleep function remains unknown although several studies indicate that it might play a role in learning and memory. To investigate what modifications paradoxical sleep may bring at the molecular level in neocortex and in hippocampal formation, we profiled gene expression in these structures in rats with different quantities of PS by cDNA microarrays approach.
No associated publication
Sex, Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Molecular signatures of cardiac defects in Down syndrome lymphoblastoid cell lines suggest altered ciliome and Hedgehog pathways.
Sex, Specimen part
View SamplesMolecular Signatures of cardiac defects in Down syndrome lymphoblastoid cell lines. In this study, we want to identify genes and pathways specifically dysregulated in atrioventricular septal defect and /or atrial septal defect + ventricular septal defect in case of trisomy 21.
Molecular signatures of cardiac defects in Down syndrome lymphoblastoid cell lines suggest altered ciliome and Hedgehog pathways.
Sex, Specimen part
View SamplesWe demonstrate that PKA signalling drives zonal conversion within adult adrenocortical lineage in a sexually dimorphic manner. Our data establish that Prkar1a genetic ablation (leading to constitutive PKA activation) in the adult adrenocortical lineage leads to endocrine hyperactivity and accelerates adrenal cortex renewal. This results in increased zona fasciculata differentiation and final conversion into reticularis-like zone. This phenomenon relies partly on sex-dependent mechanisms of cortical renewal, on which the male androgenic milieu exerts a repressive action through induction of WNT signalling, which in turn antagonizes PKA signalling and cortical cell turnover.
PKA signaling drives reticularis differentiation and sexually dimorphic adrenal cortex renewal.
Sex, Specimen part
View SamplesMolecular consequences of trisomy in lymphoblastoid cell lines from patients with Down syndrome. This project analyses differentially expressed genes between humans with trisomy 21 and humans without trisomy 21.
Molecular signatures of cardiac defects in Down syndrome lymphoblastoid cell lines suggest altered ciliome and Hedgehog pathways.
Sex, Specimen part
View Samples