The loss of loricrin, a major component of the cornified envelope, results in a delay of epidermal barrier formation. Therefore, the living layers of the epidermis are aberrantly exposed to late-stage amniotic fluid, which may serve as the signal to upregulate genes that functionally compensate for the loss of loricrin. Consistent with this hypothesis, metabolomic studies revealed marked changes in amniotic fluid between E14.5 and E16.5 dpc. In addition, we discovered that the Nrf2/Keap1 pathway detects these compositional changes and directly upregulates the expression of genes involved in the compensatory response, thus ensuring postnatal survival. In support of this finding, we demonstrate that genetically blocking the Nrf2 pathway abolishes the compensatory response, and preemptively activating Nrf2 pharmacologically rescues the delay in barrier formation in utero. Our findings reveal that the functions of Nrf2 and the composition of amniotic fluid have co-evolved to ensure the formation of a functional barrier.
Amniotic fluid activates the nrf2/keap1 pathway to repair an epidermal barrier defect in utero.
Specimen part
View SamplesThe Nrf2 transcription factor is a key player in the cellular stress response, which regulates the expression of important antioxidant enzymes and other cytoprotective proteins. We recently generated a novel transgenic mouse model to determine the function of Nrf2 in the skin. These mice revealed interesting phenotypic abnormalities, including hyperkeratosis and acanthosis. To gain insight into the underlying molecular mechanisms, we wanted to identify genes, which are differentially expressed in the skin of wild-type and mutant mice before the onset of phenotypic abnormalities.
Nrf2 links epidermal barrier function with antioxidant defense.
Sex, Treatment
View SamplesBrief expression of pluripotency-associated factors such as Oct4, Klf4, Sox2 and c-Myc (OKSM), in combination with differentiation-inducing signals, has been reported to trigger transdifferentiation of fibroblasts into other cell types. Here we show that OKSM expression in mouse fibroblasts gives rise to both induced pluripotent stem cells (iPSCs) and induced neural stem cells (iNSCs) under conditions previously shown to induce only iNSCs. Fibroblast-derived iNSC colonies silenced retroviral transgenes and reactivated silenced X chromosomes, both hallmarks of pluripotent stem cells. Moreover, lineage tracing with an Oct4-CreER labeling system demonstrated that virtually all iNSC colonies originated from cells transiently expressing Oct4, whereas ablation of Oct4+ cells prevented iNSC formation. Lastly, an alternative transdifferentiation cocktail that lacks Oct4 and was reportedly unable to support induced pluripotency yielded iPSCs and iNSCs carrying the Oct4-CreER-derived lineage label. Together, these data suggest that iNSC generation from fibroblasts using OKSM and other pluripotency-related reprogramming factors requires passage through a transient iPSC state.
Lineage conversion induced by pluripotency factors involves transient passage through an iPSC stage.
Sex, Specimen part
View SamplesTranscriptomics analyses in these Zn-deficient rats revealed the molecular basis of ESCC abrogation by miR-31 knockout: Egln3, a negative regulator of NF-FB, was shown to be a direct miR-31 target; miR-31 inhibition/deletion resulted in suppression of miR-31-associated-EGLN3-NF-KB controlled inflammatory pathways.
Abrogation of esophageal carcinoma development in miR-31 knockout rats.
Treatment
View SamplesEmbryonic stem cells (ESCs) cells run a self-renewal gene expression program, requiring the expression of certain transcription factors accompanied by a particular chromosome organization to maintain a balance between pluripotency and the capacity for rapid differentiation. However, how transcriptional regulation is linked to chromosome organization in ESCs remains enigmatic. Here we show that Cohesin exhibits a functional role in maintaining ESC identity through association with the pluripotency transcriptional network. ChIP-seq analyses of the cohesin subunit Rad21 reveal an ESC specific cohesin binding pattern that is characterized by a CTCF independent colocalization of cohesin with pluripotency related transcription factors. Upon ESC differentiation, these binding sites disappear and instead new CTCF independent Rad21 binding sites emerge, which are enriched for binding sites of transcription factors implicated in early differentiation. Furthermore, knock-down of cohesin subunits causes expression changes that are reminiscent of the depletion of key pluripotency transcription factors, demonstrating the functional relevance of the cohesin - pluripotency transcriptional network association. Finally, we show that Nanog physically interacts with the cohesin interacting proteins Stag1 and Wapl, further substantiating this association. Based on these findings we propose that a dynamic placement of cohesin by pluripotency transcription factors contributes to a chromosome organization supporting the ESC expression program.
RAD21 cooperates with pluripotency transcription factors in the maintenance of embryonic stem cell identity.
Specimen part
View SamplesPurpose: Sox2 expression marks gastric stem and progenitor cells, raising important questions regarding the genes regulated by Sox2 and the role of Sox2 itself during stomach homeostasis and disease. The goal of this study is to determine the function of and the genes regulated by Sox2 in the stomach. Methods: mRNA profiles of Sox2 WT and Sox2 KO gastric glands were generated by RNA-sequencing, in triplicate, using a Illumina HiSeq 2500 instrument, resulting in 36 million single-end 50bp reads per smaple. Sequencing reads were mapped to the mouse reference genome (mm10/GRCm38) using STAR (Dobin et al., 2013). Read counts over transcripts were calculated using HTSeq v.0.6.0 (Anders et al., 2015) based on a current Ensembl annotation file for mm10/GRCm38 (release 75). Results: Sox2 is dispensiable for gastric stem cell self-renewal and epithelial homeostasis, however modulates the expression of cancer and intestinal related genes. Overall design: mRNA profiles of stomachs from 10 week old Sox2 WT and Sox2 KO mice were generated by sequencing, in triplicate, using a Illumina HiSeq 2500.
Sox2 Suppresses Gastric Tumorigenesis in Mice.
Age, Specimen part, Cell line, Subject
View SamplesAnalysis of cardiomyocytes cultivated in 2D or age-matched 3D (Engineered heart tissue, EHT) format.
Human Engineered Heart Tissue: Analysis of Contractile Force.
Age, Specimen part
View SamplesGene expression analysis of motor cortex after spinal C3 lesion
A Systems-Level Analysis of the Peripheral Nerve Intrinsic Axonal Growth Program.
Sex, Specimen part, Time
View SamplesIdentification of Hox gene downstream genes at embryonic stages 11 and 12<br></br><br></br>Functional diversification of body parts is dependent on the formation of specialized structures along the various body axes. In animals, region-specific morphogenesis along the anterior-posterior axis is controlled by a group of conserved transcription factors encoded by the Hox genes. Although it has long been assumed that Hox proteins carry out their function by regulating distinct sets of downstream genes, only a small number of such genes have been found, with very few having direct roles in controlling cellular behavior. We have quantitatively identified hundreds of Hox downstream genes in Drosophila by microarray analysis, and validated many of them by in situ hybridizations on loss- and gain-of-function mutants. One important finding is that Hox proteins, despite their similar DNA binding properties in vitro, have highly specific effects on the transcriptome in vivo, as expression of many downstream genes responds primarily to a single Hox protein. In addition, a large fraction of downstream genes encodes realizator functions, which directly affect morphogenetic processes, such as orientation and rate of cell divisions, cell-cell adhesion and communication, cell shape and migration, or cell death. Focusing on these realizators, we provide a framework for the morphogenesis of the maxillary segment. Since the genomic organization of Hox genes and the interaction of Hox proteins with specific cofactors are conserved in vertebrates and invertebrates, and similar classes of downstream genes are regulated by Hox proteins across the metazoan phylogeny, our findings represent a first step towards a mechanistic understanding of morphological diversification within a species as well as between species.
Comparative analysis of Hox downstream genes in Drosophila.
Age, Time
View SamplesThe hormone calcitonin (CT) is primarily known for its pharmacologic action as an inhibitor of bone resorption, yet CT-deficient mice display increased bone formation. These findings raised the question about the underlying cellular and molecular mechanism of CT action. Here we show that either ubiquitous or osteoclast-specific inactivation of the murine CT receptor (CTR) causes increased bone formation. CT negatively regulates the osteoclast expression of Spns2 gene, which encodes a transporter for the signaling lipid sphingosine 1-phosphate (S1P). CTR-deficient mice show increased S1P levels, and their skeletal phenotype is normalized by deletion of the S1P receptor S1P3. Finally, pharmacologic treatment with the non-selective S1P receptor agonist FTY720 causes increased bone formation in wildtype, but not in S1P3-deficient mice. This study redefines the role of CT in skeletal biology, confirms that S1P acts as an osteoanabolic molecule in vivo, and provides evidence for a pharmacologically exploitable crosstalk between osteoclasts and osteoblasts.
Calcitonin controls bone formation by inhibiting the release of sphingosine 1-phosphate from osteoclasts.
Specimen part, Treatment
View Samples