MED23, a subunit of the Mediator coactivator complex, is important for the expression of a subset of MAPK/ERK pathway-dependent target genes; however, the genes in this subset varies between cell types. MAPK/ERK pathway-dependent processes are essential for T-cell development and function, but whether MED23 has a role in this context is unknown. We generated Med23 conditional knockout mice and induced Med23 deletion in early T cell development using the lineage specific Lck-Cre transgene. While the total cell number and distribution of cell populations in the thymuses of Med23flox/flox;Lck-Cre mice were essentially normal, MED23 null T-cells failed to efficiently populate the peripheral lymphoid organs. MED23 null thymocytes displayed decreased expression of the MAPK/ERK-responsive genes Egr1, Egr2, as well as of the membrane glycoprotein Cd52 (CAMPATH-1). MED23 null CD4 single-positive thymocytes also showed decreased expression of KLF2 (LKLF), a T cell master regulatory transcription factor. Indeed, similarities between the phenotypes of mice lacking MED23 or KLF2 in T-cells suggest that KLF2 deficiency in MED23 null T-cells is one of their key defects. Mechanistic experiments using MED23 null MEFs further suggest that MED23 is required for full activity of the MAPK-responsive transcription factor MEF2, which has previously been shown to mediate Klf2 expression. In summary, our data indicate that MED23 has critical roles in enabling T-cells to populate the peripheral lymphoid organs, possibly by potentiating MEF2-dependent expression of the T-cell transcription factor KLF2.
T-cells null for the MED23 subunit of mediator express decreased levels of KLF2 and inefficiently populate the peripheral lymphoid organs.
Sex, Specimen part
View SamplesWhile histone deacetylase (HDAC) inhibitors are thought to regulate gene expression by post-translational modification of histone as well as non-histone proteins. While histone hyperacetylation has long been considered the paradigmatic mechanism of action, recent genome-wide profiles indicate more complex interactions with the epigenome. In particular, HDAC inhibitors also induce histone deacetylation at the promoters of highly active genes, resulting in gene suppression. This was linked to the loss of histone acetyltransferase (HAT) binding. To illustrate pre-clinical utility of the HDAC inhibitor SAHA as a therapeutic, we show reversal of diabetes-associated EP300 target genes in diabetic HAECs of primary origin. These results were confirmed using SAHA, C646 (EP300/CREBBP inhibitor) or EP300 siRNA. These findings suggest the inhibition of gene expression by SAHA is mediated by EP300 function and provide a rationale for clinical trials of safety and efficacy in patients with diabetes. Overall design: Human aortic endothelial cells from a diabetic and non-diabetic individual were stimulated with DMSO (control), SAHA (2 µM, HDAC inhibitor) or C646 (10 µM, EP300 inhibitor) for 12 hours, or EP300 siRNA or non-target siRNA (control) for 4 hours, followed by 48 hours in fresh media. Study performed in triplicate.
Systems approach to the pharmacological actions of HDAC inhibitors reveals EP300 activities and convergent mechanisms of regulation in diabetes.
No sample metadata fields
View SamplesPurpose: We applied cDNA molecule counting using unique molecular identifiers combined with high-throughput sequencing to study the transcriptome of individual mouse embryonic stem cells, with spike-in controls to monitor technical performance. We further examined transcriptional noise in the embryonic stem cells. Overall design: One 96-well plate of single-stranded cDNA libraries generated from 96 single R1 mouse embryonic stem cells sequenced on two lanes, and one 96-well plate of the same libraries further amplified by 9 PCR cycles sequenced on one lane.
Quantitative single-cell RNA-seq with unique molecular identifiers.
No sample metadata fields
View SamplesThe inability of the adult mammalian heart to regenerate following injury represents a major barrier in cardiovascular medicine. In contrast, the neonatal mammalian heart retains a transient capacity for regeneration, which is lost shortly after birth. Defining the molecular mechanisms that govern regenerative capacity in the neonatal period remains a central goal in cardiac biology. Here, we construct a transcriptional atlas of multiple cardiac cell populations, which enables comparative analyses of the regenerative (neonatal) versus non-regenerative (adult) state for the first time. This work provides a comprehensive transcriptional resource of multiple cardiac cell populations during cardiac development, repair and regeneration. Our findings define a transcriptional program underpinning the neonatal regenerative state and identifies an epigenetic barrier to re-induction of the regenerative program in adult cardiomyocytes. Overall design: Cardiomyocytes, fibroblasts, leukocytes and endothelial cells from infarcted and non-infarcted neonatal (P1) and adult (P56) hearts were isolated by enzymatic dissociation and FACS. RNA sequencing (RNA-seq) was performed on these cell populations to generate a transcriptomic atlas of the major cardiac cell populations during cardiac development, repair and regeneration. In addition, we surveyed the epigenetic landscape of cardiomyocytes during post-natal maturation by performing deep sequencing of accessible chromatin regions using the Assay for Transposase-Accessible Chromatin (ATAC-seq) from purified cardiomyocyte nuclei (P1, P14 and P56).
Multicellular Transcriptional Analysis of Mammalian Heart Regeneration.
Specimen part, Treatment, Subject
View SamplesDectin1 controls the recruitment of TLR9 to -1,3 glucan beads containing phagosomes. We sought to determine whether Dectin-1 also plays a role in controlling TLR9 dependent gene expression.
Dectin-1 Controls TLR9 Trafficking to Phagosomes Containing β-1,3 Glucan.
Specimen part
View SamplesEpigenetic modifications have emerged as central players in the coordination of gene expression networks during cardiac development. While several studies have investigated the role of histone modifications during heart development, relatively little is known about the role of DNA methylation. The purpose of the current study was to determine whether DNA methylation plays an important role in guiding transcriptional changes during the neonatal period, which is an important developmental window for cardiac maturation and cardiomyocyte cell cycle arrest. We used methyl binding domain protein sequencing (MBD-seq) and mRNA-seq to profile DNA methyation and gene expression respectively in neonatal hearts at P1 and P14 stages. Thousands of differentially methylated regions (DMRs) were identified between P1 and P14, the vast majority of which were hypermethylated. Gene ontology analysis revealed that these hypermethylated genes were associated with transcriptional regulation of important developmental signaling pathways, including Hedgehog, BMP, TGF beta, FGF and Wnt/b-catenin signaling. A significant enrichment for myogenic transcription factors and Smad2/3/4 binding sites was also noted among differentially methylated peaks at P14. This study provides novel evidence for widespread alterations in DNA methylation during post-natal heart maturation and suggests that DNA methylation plays an important role in cardiomyocyte cell cycle arrest during the neonatal period. Overall design: mRNA-seq to profile gene expression in neonatal hearts at P1 and P14 stages (post-natal day 1 and 14 respectively) in three biological replicates.
Dynamic changes in the cardiac methylome during postnatal development.
No sample metadata fields
View SamplesWe analyzed the transcriptional profile of colon and small-intestinal (SI) tissues in response to ex-vivo colonization with members of the gut microbiota. Tissues were dissected from SPF or GF mice, and connected to the ex-vivo gut organ culture system. Then, microbial cultures or fecal samples were infused into the lumen, and tissues were processed in different time points, as indicated below.
An Intestinal Organ Culture System Uncovers a Role for the Nervous System in Microbe-Immune Crosstalk.
Sex, Age
View SamplesExplore DNA methylation in focal amygdala stimulation model of epilepsy and its relationship to gene expression. Overall design: Examination of expression changes in stimulated rats compared to sham operated animals in focal amygdala stimulation model of epilpesy.
Etiology matters - Genomic DNA Methylation Patterns in Three Rat Models of Acquired Epilepsy.
No sample metadata fields
View SamplesWithin the human gut reside diverse microbes coexisting with the host in a mutually advantageous relationship. We comprehensively identified the modulatory effects of phylogenetically diverse human gut microbes on the murine intestinal transcriptome. Gene-expression profiles were generated from the whole-tissue intestinal RNA of mice colonized with various single microbial strains. The selection of microbe-specific effects, from the transcriptional response, yielded only a small number of transcripts, indicating that symbiotic microbes have only limited effects on the gut transcriptome overall. Moreover, none of these microbe-specific transcripts was uniformly induced by all microbes. Interestingly, these responsive transcripts were induced by some microbes but repressed by others, suggesting different microbes can have diametrically opposed consequences.
Mining the Human Gut Microbiota for Immunomodulatory Organisms.
Sex, Age, Specimen part
View SamplesHere we analyzed the transcriptional profile of S-IECs sorted from GF and monocolonized mice (C. histolyticum and B. adolescentis), as well as SPF mice colonized with SFB or not.
Identifying species of symbiont bacteria from the human gut that, alone, can induce intestinal Th17 cells in mice.
Sex, Age
View Samples