AIMS/HYPOTHESIS: Manoeuvres aimed at increasing beta cell mass have been proposed as regenerative medicine strategies for diabetes treatment. Raf-1 kinase inhibitor protein 1 (RKIP1) is a common regulatory node of the mitogen-activated protein kinase (MAPK) and nuclear factor B (NF-B) pathways and therefore may be involved in regulation of beta cell homeostasis. The aim of this study was to investigate the involvement of RKIP1 in the control of beta cell mass and function.
The role of Raf-1 kinase inhibitor protein in the regulation of pancreatic beta cell proliferation in mice.
Age, Specimen part
View SamplesVAChT KDHOM mice have a 70% decrease in the vesicular acetylcholine transporter (VAChT) and this leads to a systemic decrease in ACh release and cardiac dysfunction.
An analysis of the myocardial transcriptome in a mouse model of cardiac dysfunction with decreased cholinergic neurotransmission.
Sex, Age, Specimen part
View SamplesWound healing is an essential homeostatic mechanism that maintains the epithelial barrier integrity after tissue damage. Although we know the main events participating in the healing of a wound, many of the underlying molecular mechanisms remain unclear. Genetically amenable systems, such as wound healing in Drosophila imaginal discs, do not model all aspects of the repair process, but allow exploring many unanswered features of the healing response; e.g., which are the signal(s) responsible for initiating tissue remodeling? How is the sealing of the epithelia achieved? Or which are the inhibitory cues that cancel the healing machinery upon completion? Answering these and other questions demands in first place the identification and functional analysis of wound-specific genes. A variety of different microarray analyses of murine and humans have identified characteristic profiles of gene expression at the wound site, however, very few functional studies in healing regulation have been carried out. We developed an experimentally controlled method to culture imaginal discs that allows live imaging and biochemical analysis and is healing-permissive. Employing this approach, we performed a comparative genome-wide profiling between those Drosophila imaginal cells actively involved in healing versus their non-engaged siblings. This lets us identify a set of potential wound-specific genes. Importantly, besides identifying and categorizing new genes, we functionally tested many of their gene products by genetic interference and overexpression in a healing assay. This non-saturated analysis defines a relevant set of new genes whose changes in expression levels are functionally significant for proper tissue repair. There is promise that our newly identified wound-healing genes will guide future work in the more complex mammalian wound response.
Identification and functional analysis of healing regulators in Drosophila.
Specimen part, Treatment
View SamplesWhole-genome expression of peripheral blood leukocytes was measured in 22 patients and 24 controls using the Human Gene 1.0 ST array by Affymetrix
Transcriptomic profile reveals gender-specific molecular mechanisms driving multiple sclerosis progression.
Sex, Age, Specimen part, Disease
View SamplesMost metabolic studies are conducted in male animals; thus, the molecular mechanism controlling gender-specific pathways has been neglected, including sex-dependent responses to peroxisome proliferator-activated receptors (PPARs). Here we show that PPARalpha has broad female-dependent repressive actions on hepatic genes involved in steroid metabolism and inflammation. In males, this effect is reproduced by the administration of synthetic PPARalpha ligand. Using the steroid hydroxylase gene Cyp7b1 as a model, we elucidated the molecular mechanism of this PPARalpha-dependent repression. Initial sumoylation of the ligand-binding domain of PPARalpha triggers the interaction of PPARalpha with the GA-binding protein alpha bound to the target promoter. Histone deacetylase is then recruited, and histones and adjacent Sp1-binding site are methylated. These events result in the loss of Sp1-stimulated expression, and thus the down-regulation of Cyp7b1. Physiologically, this repression confers protection against estrogen-induced intrahepatic cholestasis, paving the way for a novel therapy against the most common hepatic disease during pregnancy.
Sumoylated PPARalpha mediates sex-specific gene repression and protects the liver from estrogen-induced toxicity in mice.
No sample metadata fields
View SamplesAim: To examine transcriptional changes in DLD-1 cells exposed to softer matrices (2 kPa and 55 kPa) and identify the chromosomes that are enriched with maximmally deregulated genes Methods: DLD-1 cells (otherwise growing on stiff tissue culture plastic substrates) were exposed to softer matrices for 90 minutes and to collagen coated glass coverslips (served as control) served as control) Results: RNA sequencing revealed nearly equivalent transcriptional deregulation in cells on both the polyacrylamide matrices (783 genes up and 872 genes down on 2 kPa, 649 genes up and 783 genes down on 55 kPa) when compared to cells on glass. Additionally, GO classification revealed that unique sets of transcriptionally deregulated genes (log fold=2) belonged to pathways associated with transcription regulation, chromatin organization, cell cycle and DNA damage/repair Results: We identified chromosomes 1, 2, 3, 6, 7, 10, 12, 14, 17 and 19 to be maximally enriched with the deregulated genes on softer matrices (log fold=2), while chromosomes 13, 18 and 21 showed minimal enrichment of deregulated genes. We also examined the spatial organization of chromosome 1, 18 and 19 territories in cells on softer matrices (using 3D-FISH) and observed that these chromosomes were mislocalized away from their conserved nuclear locations Conclusions: Our study reports the transcriptomic changes in DLD-1 cells upon lowering of extracellular substrate stiffnes and its impact on the spatial positioning of chromosome territories Overall design: RNA Seq profiles for DLD-1 cells on soft polyacrylamide matrices of ~2 kPa and ~55 kPa (reference - glass) were generated across 2 independent biological replicates using Illumina HiSeq platform
Emerin modulates spatial organization of chromosome territories in cells on softer matrices.
Cell line, Subject
View SamplesThe SWR1 complex replaces the canonical histone H2A with the variant H2A.Z (Htz1 in yeast) at specific chromatin regions. This dynamic alteration in nucleosome structure provides a molecular mechanism to regulate transcription. Here we analysed the transcription profiles of single and double mutants and wild-type cells by whole-genome microarray analysis. Our results indicate that genome-wide transcriptional misregulation in htz1 can be partially or totally suppressed if SWR1 is not formed (swr1), if it forms but cannot bind to chromatin (swc2), or if it binds to chromatin but has no histone replacement activity (swc5). These results suggest that in htz1 the nucleosome remodelling activity of SWR1 affects chromatin integrity because of an attempt to replace H2A with Htz1 in the absence of the latter.
The SWR1 histone replacement complex causes genetic instability and genome-wide transcription misregulation in the absence of H2A.Z.
No sample metadata fields
View SamplesPhytochromes are red/far red photosensors regulating numerous developmental programs in plants. Among them phytochrome A (phyA) is essential to enable seedling de-etiolation in continuous far-red (FR) light a condition mimicking the environment under a dense canopy. The ecological relevance of this response is demonstrated by the high mortality rate of phyA mutants germinating in deep vegetational shade. phyA signaling involves a direct interaction of the photoreceptor with members of the bHLH transcription factor family, PIF1 and PIF3 (Phytochrome Interacting Factor). Here we investigated the involvement of PIF4 and PIF5 in phyA signaling and found that they redundantly control de-etiolation in FR light. The pif4pif5 double mutant is hypersensitive to low fluence rates of FR light. This phenotype is dependent on FR light perception by phyA but does not rely on alterations of the phyA level. Our microarrays analysis shows that PIF4 and PIF5 are part of an inhibitory mechanism repressing the expression of some light-responsive genes in the dark and are also needed for full expression of several growth-related genes in the light. Unlike PIF1 and PIF3, PIF4 and PIF5 are not degraded in response to FR light indicating that they are light-regulated by a different mechanism. Our genetic analysis suggests that this is achieved through the sequestration of these PIFs by the closely related bHLH transcription factor HFR1 (long Hypocotyl in FR light).
Phytochrome interacting factors 4 and 5 redundantly limit seedling de-etiolation in continuous far-red light.
No sample metadata fields
View SamplesTranscriptional silencing of terminal differentiation genes by the Polycomb group (PcG) machinery is emerging as a key feature of precursor cells in stem cell lineages. How, then, is this epigenetic silencing reversed for proper cellular differentiation? Here we investigate how the developmental program reverses local PcG action to allow expression of terminal differentiation genes in the Drosophila male germline stem cell lineage. We find that the silenced state, set up in precursor cells, is relieved through developmentally regulated sequential events at promoters once cells commit to spermatocyte differentiation. The programmed events include global down-regulation of PRC2, recruitment of hypophosphorylated RNA Polymerase II (Pol II) to promoters, as well as expression and action of cell-type specific homologs of subunits of TFIID (tTAFs). In addition, action of tMAC, a tissue specific version of the MIP/dREAM complex, is required both for recruitment of tTAFs to target differentiation genes and for proper cell-type specific localization of PRC1 components and tTAFs to the spermatocyte nucleolus. Together, action of the tMAC and tTAF cell-type specific chromatin and transcription machinery leads to loss of
Sequential changes at differentiation gene promoters as they become active in a stem cell lineage.
Time
View SamplesOur study describes in detail the role of Bmp2 during cardiac valve developmnent and its implication in Notch pathway activation. Overall design: Hearts were isolated from WT and Bmp2GOF;Nkx2.5-Cre mouse embryos at stage E9.5 and their expression profile characterized by RNA-seq
Bmp2 and Notch cooperate to pattern the embryonic endocardium.
Specimen part, Subject
View Samples