The aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor involved in adaptive cell functions, and highly active in the epidermis. AhR-ligands can accelerate keratinocyte differentiation, but a precise role for AhR in the skin barrier is unknown. We here show that transepidermal water loss (TEWL), a parameter of skin barrier integrity, is high in AhR-deficient (AhR-KO) mice. Experiments with conditionally AhR-deficient mouse lines identified keratinocytes as the major responsible cell population for high TEWL. Electron microscopy showed weaker inter-cellular connectivity in the epidermis of keratinocytes in AhR-KO mice, and gene expression analysis identified many barrier-associated genes as AhR targets. Moreover, AhR-deficient mice had higher inter-individual differences in their microbiome. Interestingly, removing AhR-ligands from the diet of wild-type mice mimicked AhR-deficiency regarding the impaired barrier. Vice versa, re-addition of the plant-derived ligand indole-3-carbinol (I3C) rescued the barrier deficiency even in aged mice. Our results suggest that functional AhR expression is critical for skin barrier integrity and that AhR represents a molecular target for the development of novel therapeutic approaches for skin barrier diseases, including dietary intervention.
Aryl Hydrocarbon Receptor in Keratinocytes Is Essential for Murine Skin Barrier Integrity.
Sex, Specimen part, Treatment, Time
View SamplesLoss of immune function and an increased incidence of myeloid leukemia are two of the most clinically significant consequences of aging of the hematopoietic system. To better understand the mechanisms underlying hematopoietic aging, we evaluated the cell intrinsic functional and molecular properties of highly purified long-term hematopoietic stem cells (LT-HSCs) from young and old mice. We found that LT-HSC aging was accompanied by cell autonomous changes, including increased stem cell self-renewal, differential capacity to generate committed myeloid and lymphoid progenitors, and diminished lymphoid potential. Expression profiling revealed that LT-HSC aging was accompanied by the systemic down-regulation of genes mediating lymphoid specification and function and up-regulation of genes involved in specifying myeloid fate and function. Moreover, LT-HSCs from old mice expressed elevated levels of many genes involved in leukemic transformation. These data support a model in which age-dependent alterations in gene expression at the stem cell level presage downstream developmental potential and thereby contribute to age-dependent immune decline, and perhaps also to the increased incidence of leukemia in the elderly.
Cell intrinsic alterations underlie hematopoietic stem cell aging.
No sample metadata fields
View SamplesWe analyzed expression of 81 normal muscle samples from humans of varying ages, and have identified a molecular profile for aging consisting of 250 age-regulated genes. This molecular profile correlates not only with chronological age but also with a measure of physiological age. We compared the transcriptional profile of muscle aging to previous transcriptional profiles of aging in kidney and brain, and found a common signature for aging in these diverse human tissues. The common aging signature consists of six genetic pathways; four pathways increase expression with age (genes in the extracellular matrix, genes involved in cell growth, genes encoding factors involved in complement activation, and genes encoding components of the cytosolic ribosome), while two pathways decrease expression with age (genes involved in chloride transport and genes encoding subunits of the mitochondrial electron transport chain). We also compared transcriptional profiles of aging in human to those of the mouse and fly, and found that the electron transport chain pathway decreases expression with age in all three organisms, suggesting that this may be a public marker for aging across species.
Transcriptional profiling of aging in human muscle reveals a common aging signature.
Sex
View SamplesQuiescent splenic B cells purified from Cg1-cre Prmt5F/F cells and Cg1-cre control mice. Resting B cells were plated on feeder cells expressing CD40L and BAFF and supplemented with IL-4 for activation. Four days later, the resulting activated germinal center-like B cells were purified and RNA extracted and processed for HiSeq. Four independent samples of each genotype were processed and analyzed. Overall design: 2 Experiments, 2 samples of each genotype per experiment (Exp 1: Samples 1,2,7,8 ; Exp 2: Samples 3,4,5,6)_ PRMT5 FF Cg1cre: Samples 1,2,3,4_ Cg1cre controls: Samples 5,6,7,8
PRMT5 is essential for B cell development and germinal center dynamics.
Cell line, Subject
View SamplesHIV-1 Vpr protein is a multifunctional protein which perturbs human transcriptome and interacts with a number of cellular proteins. In this study, we have attempted to explore the efffects of Vpr on human transcriptome and have identified several genes which are involved in innate immune responses.
Genome-wide transcriptional profiling reveals that HIV-1 Vpr differentially regulates interferon-stimulated genes in human monocyte-derived dendritic cells.
Specimen part, Treatment
View SamplesTo examine the impact of tumors on the immune system, we compared global gene expression profiles of peripheral blood T cells from previously untreated patients with B cell chronic lymphocytic leukemia (CLL) with those from age-matched healthy donors. Although the cells analyzed were not part of the malignant clone, analysis revealed differentially expressed genes, mainly involved in cell differentiation in CD4 cells and defects in cytoskeleton formation, vesicle trafficking, and cytotoxicity in CD8 cells of the CLL patients. In coculture experiments using CLL cells and T cells from healthy allogeneic donors, similar defects developed in both CD4 and CD8 cells. These changes were induced only with direct contact and were not cytokine mediated. Identification of the specific pathways perturbed in the T cells of cancer-bearing patients will allow us to assess steps to repair these defects, which will likely be required to enhance antitumor immunity.
Chronic lymphocytic leukemia cells induce changes in gene expression of CD4 and CD8 T cells.
No sample metadata fields
View SamplesUstilago maydis is a plant-pathogenic fungus that establishes a biotrophic relationship with its host Zea mays. The biotrophic interaction is initiated upon host penetration, and involves expansion of the host plasma membrane around hyphae, which is thought to facilitate the exchange of nutrients and virulence factors. Transcriptional regulators involved in the establishment of an infectious dikaryon and penetration into the host have been identified, however, regulators involved in the post-penetration stages remained to be elucidated. In the study we report the identification of an Ustilago maydis forkhead transcription factor, Fox1, which is exclusively expressed during biotrophic development. Deletion of fox1 results in reduced virulence and impaired tumour development in planta. fox1 hyphae induce plant defences including the overproduction and accumulation of H2O2 in and around infected cells. This oxidative burst acts as an intercellular signal, which elicits a specific host defence response phenotypically represented by the encasement of proliferating hyphae in extensions of the plant cell wall. Maize microarrays experiments were performed to identify genes involved in the observed plant defence responses on leaf tissue infected with U. maydis strain SG200fox1 4 dpi.
The Ustilago maydis forkhead transcription factor Fox1 is involved in the regulation of genes required for the attenuation of plant defenses during pathogenic development.
Specimen part
View SamplesAdjacent alternative 3’ splice sites, those separated by =18nt, provide a unique problem in the study of alternative splicing regulation; there is overlap of the cis-elements that define the adjacent sites. Identification of the intron''s 3'' end depends upon sequence elements that define the branchpoint, polypyrimidine tract and terminal AG dinucleotide. Starting with RNA-seq data from germline-enriched and somatic cell-enriched C. elegans samples, we identify hundreds of introns with adjacent alternative 3’ splice sites. We identify 203 events that undergo tissue-specific alternative splicing. For these, the regulation is mono-directional, with somatic cells preferring to splice at the distal 3'' splice site and germline cells showing a distinct shift towards usage of the adjacent proximal 3'' splice site. Splicing patterns in somatic cells follow consensus rules of 3’ splice site definition, using sites with a short stretch of pyrimidines and an AG dinucleotide. Splicing in germline cells occurs at proximal 3'' splice sites that frequently lack a polypyrimidine tract or, occasionally, the AG dinucleotide. We provide evidence that use of germline-specific proximal 3'' splice sites is conserved across Caenorhabditis species. We propose that divergent mechanisms exist between germline and somatic cells in determining an intron terminus at adjacent alternative 3’ splice sites. Overall design: Examination of alternative splicing changes between germline- and somatic-cell enriched samples as well as nonsense-mediated decay mutants.
Coordinated tissue-specific regulation of adjacent alternative 3' splice sites in C. elegans.
Specimen part, Cell line, Subject
View SamplesHIV-1 Vpr protein is a multifunctional protein which perturbs human transcriptome and interacts with a number of cellular proteins. In this study, we have attempted to explore the efffects of Vpr on human transcriptome and have identified several genes which are involved in innate immune respone and cell signaling pathways.
HIV-1 Vpr induces interferon-stimulated genes in human monocyte-derived macrophages.
Specimen part, Subject
View SamplesApproximately 5% of all breast cancers can be attributed to an inherited mutation in one of two cancer susceptibility genes, BRCA1 and BRCA2. We searched for genes that have the potential to distinguish healthy BRCA1 and BRCA2 mutation carriers from non-carriers based on differences in expression profiling. Using expression microarrays we compared gene expression of irradiated lymphocytes from BRCA1 and BRCA2 mutation carriers versus control non-carriers. We identified 137 probe sets in BRCA1 carriers and 1345 in BRCA2 carriers with differential gene expression. Gene Ontology analysis revealed that most of these genes relate to regulation pathways of DNA repair processes, cell cycle regulation and apoptosis. Real-time PCR was performed on the 36 genes which were most prominently differentially expressed in the microarray assay; 21 genes were shown to be significantly differentially expressed in BRCA1 or BRCA2 mutation carriers as compared to controls (p<0.05). Based on a validation study with 40 mutation carriers and 17 non-carriers, a multiplex model that included six or more coincidental genes of 18 selected genes was constructed in order to predict the risk of carrying a mutation. The results using this model showed sensitivity 95% and specificity 88%. In summary, our study provides insight into the biological effect of heterozygous mutations in BRCA1 and BRCA2 genes in response to ionizing irradiation induced DNA damage. We also suggest a set of 18 genes that can be used as a prediction and screening tool for BRCA1 or BRCA2 mutational carriers by using easily obtained lymphocytes.
Determination of molecular markers for BRCA1 and BRCA2 heterozygosity using gene expression profiling.
Specimen part
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