Sirtuin 1 (SIRT1) is involved in both aging and circadian-clock regulation, yet the link between the two processes in relation to SIRT1 function is not clear. Using Sirt1-deficient mice, we found that Sirt1 and Period 2 (Per2) constitute a reciprocal negative regulation loop that plays important roles in modulating hepatic circadian rhythmicity and aging. Sirt1-deficient mice exhibited profound premature aging and enhanced acetylation of histone H4 on lysine16 (H4K16) in the promoter of Per2, the latter of which leads to its overexpression; in turn, Per2 suppresses Sirt1 transcription through binding to the Sirt1 promoter at the Clock/Bmal1 site. This negative reciprocal relationship between SIRT1 and PER2 was also observed in human hepatocytes. We further demonstrated that the absence of Sirt1 or the ectopic overexpression of Per2 in the liver resulted in a dysregulated pace of the circadian rhythm. The similar circadian rhythm was also observed in aged wild type mice. The interplay between Sirt1 and Per2 modulates aging gene expression and circadian-clock maintenance.
Negative reciprocal regulation between Sirt1 and Per2 modulates the circadian clock and aging.
Age, Specimen part
View SamplesL-type voltage gated Ca channels play a critical role in E-C coupling in cardiac muscle. alpha1C is associated with beta auxiliary subunits (b1-b4), which regulate cardiac Ca channel gating properties. Here we report a preliminary exploratory study suggesting a novel role of beta4 subunit in heart. We observed that overexpression of beta4 subunit increases the expression of a wide variety of endogenous genes related to antiviral activity. This includes genes in the downstream signalling of RIG-1 pathway such as RIG-1, Irf7 and Ifitm3. The increase expression of these factors may have an antiviral protective role against infection. Overall design: Examination of an overall differential expression by the beta4 subunit
The β<sub>4</sub> subunit of Ca<sub>v</sub>1.2 channels is required for an optimal interferon response in cardiac muscle cells.
Specimen part, Cell line, Subject
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Genome-wide DNA methylation analysis of articular chondrocytes reveals a cluster of osteoarthritic patients.
Sex, Age, Specimen part, Disease, Disease stage
View SamplesThe aim of this study is to identify, for the first time, the genome-wide DNA methylation profiles of human articular chondrocytes from OA and healtly cartilage samples.
Genome-wide DNA methylation analysis of articular chondrocytes reveals a cluster of osteoarthritic patients.
Sex, Age, Specimen part, Disease, Disease stage
View SamplesIn this study, we describe the impact of genetic variation on transcript abundance in an F2 population of Arabidopsis thaliana. The RNA-seq resource generated by this study is suitable for expression quantitative trait locus (eQTL) mapping. From the aligned RNA-seq reads, and available genomic data for each of the parents of the cross, we imputed the genomes of each F2 individual (to allow genetic mapping of RNA abundance traits; briefly, genetic differences in aligned RNA-seq reads were used to impute each F2 genome). Our results show that heritable differences on gene expression can be detected using F2 populations (that is, single F2 plants), and shed light on the control of expression differences among strains of this reference plant. Overall design: 183 samples consisting of single F2 plants of a cross between Arabidopsis thaliana accessions 8230 and 6195 were generated. For each sample, RNA was collected from the aerial shoot at the 9th true leaf stage, and Illumina mRNA-seq libraries were constructed. Using these libraries, 50 bp single end RNA-seq Illumina reads were generated for each sample, and used to quantify gene expresison in each individual. The resulting expression phenotypes are suitable for genetic mapping of the control of gene expression differences in the species.
Epistatic and allelic interactions control expression of ribosomal RNA gene clusters in Arabidopsis thaliana.
Specimen part, Subject
View SamplesSignaling through the thrombospondin-1 receptor CD47 broadly limits cell and tissue survival of stress, but the molecular mechanisms are incompletely understood. We now show that loss of CD47 permits sustained proliferation of primary murine endothelial cells and enables these cells to spontaneously reprogram to form multipotent embryoid bodies. c-Myc, Klf4, Oct4, and Sox2 expression is elevated in CD47-null endothelial cells, in several tissues of CD47- or thrombospondin-1-null mice, and in a human T cell line lacking CD47. CD47 knockdown acutely increases mRNA levels of c-Myc and other stem cell transcription factors in cells and in vivo, whereas CD47 ligation by thrombospondin-1 suppresses c-Myc expression. The inhibitory effects of increasing CD47 levels can be overcome by maintaining c-Myc expression and are absent in cells with dysregulated c-Myc. Thus, CD47 antagonists enable cell self-renewal and reprogramming by overcoming negative regulation of c-Myc and other stem cell transcription factors.
Thrombospondin-1 signaling through CD47 inhibits self-renewal by regulating c-Myc and other stem cell transcription factors.
Specimen part, Cell line
View SamplesInactivating mutations in the zinc finger gene PHF6 are seen in approximately 40% of adult T-cell acute lymphoblastic leukemias (T-ALLs) and 3% of adult acute myeloid leukemias (AMLs). The absence of PHF6 mutations in B-cell lineage malignancies has led to the hypothesis that PHF6 may act as a lineage-specific tumor suppressor gene. Here, we demonstrate that PHF6 plays a critical role in regulating B-cell identity in the context of B-cell precursor acute lymphoblastic leukemia (preB-ALL). Transplantation of Phf6 knockout preB-ALL cells (hereafter referred to as Phf6KO cells) into immunocompetent syngeneic recipients resulted in the development of a fully penetrant lymphoma-like disease. Strikingly, the resulting lymphomas showed robust up-regulation of the canonical T-cell marker CD4, suggesting that Phf6KO cells adopt a T-cell program in the context of leukemogenesis. RNA sequencing analysis revealed numerous differentially expressed (DE) genes in Phf6WT and Phf6KO cells, including a significant down-regulation of genes and gene sets involved in pathways important for B-cell development. Chromatin immunoprecipitation followed by high-throughput sequencing analysis revealed that PHF6 co-localizes with H3K27ac signals close to the transcription start sites (TSSs) and enhancer regions of a significant proportion of DE genes. Notably, regions flanking the TSS of DE genes showed significant enrichment for binding sites of several well-described master regulators of B-cell development, including PU.1, EGR-1, EBF-1, NF-kB, TCF3 and TCF12. We found that PHF6 and TCF12 physically interact in preB-ALL cells, suggesting that these factors act synergistically in the establishment and maintenance of B-cell identity. In addition, we found that a human PHF6 mutant T-ALL cell line has an incompletely rearranged IGH locus, strongly suggesting that T-ALL can have a B-cell origin. These findings reveal an essential role for PHF6 in the establishment and maintenance of B-cell identity in preB-ALL by directly activating genes that are crucial for B-cell lineage commitment and maintenance. Collectively, these results indicate that loss of function of PHF6 in preB-ALL leads to an unstable cellular state in which cells acquire alternate developmental programs (such as the T-lineage program) to survive, potentially explaining the apparent absence of PHF6 mutations in human B cell-lineage malignancies. Overall design: Gene expression profiles by RNA-Seq of 3 Phf6 wild-type preB-ALL cells, 3 shPhf6 preB-ALL cells, 6 Phf6 knockout (2 different sgRNAs) preB-ALL cells
PHF6 regulates phenotypic plasticity through chromatin organization within lineage-specific genes.
Specimen part, Cell line, Subject
View Samplesd-serine is naturally present throughout the human body. It is also used as add-on therapy for treatment-refractory schizophrenia. d-Serine interacts with the strychnine-insensitive glycine binding site of NMDA receptor, and this interaction could lead to potentially toxic activity (i.e., excitotoxicity) in brain tissue. The transcriptomic changes that occur in the brain after d-serine exposure have not been fully explored.
D-Serine exposure resulted in gene expression changes implicated in neurodegenerative disorders and neuronal dysfunction in male Fischer 344 rats.
Sex
View SamplesSkin and bladder epithelia form effective permeability barriers through the activation of distinct differentiation gene programs. Employing a genome-wide gene expression study, we identified transcription regulators whose expression correlates highly with that of differentiation markers both in bladder and skin, including the Grainyhead factor Get1/Grhl3, already known to be important for epidermal barrier formation. In the bladder, Get1 is most highly expressed in the differentiated umbrella cells and its mutation in mice leads to a defective bladder epithelial barrier formation due to failure of apical membrane specialization. Genes encoding components of the specialized urothelial membrane, the uroplakins, were downregulated in Get1-/- mice. At least one of these genes, Uroplakin II, is a direct target of Get1. The urothelial-specific activation of the Uroplakin II gene is due to selective binding of Get1 to the Uroplakin II promoter in urothelial cells, most likely regulated by histone modifications. These results demonstrate a key role for Get1 in urothelial differentiation and barrier formation.
The epidermal differentiation-associated Grainyhead gene Get1/Grhl3 also regulates urothelial differentiation.
Specimen part
View SamplesSkin and bladder epithelia form effective permeability barriers through the activation of distinct differentiation gene programs. Employing a genome-wide gene expression study, we identified transcription regulators whose expression correlates highly with that of differentiation markers both in bladder and skin, including the Grainyhead factor Get1/Grhl3, already known to be important for epidermal barrier formation. In the bladder, Get1 is most highly expressed in the differentiated umbrella cells and its mutation in mice leads to a defective bladder epithelial barrier formation due to failure of apical membrane specialization. Genes encoding components of the specialized urothelial membrane, the uroplakins, were downregulated in Get1-/- mice. At least one of these genes, Uroplakin II, is a direct target of Get1. The urothelial-specific activation of the Uroplakin II gene is due to selective binding of Get1 to the Uroplakin II promoter in urothelial cells, most likely regulated by histone modifications. These results demonstrate a key role for Get1 in urothelial differentiation and barrier formation.
The epidermal differentiation-associated Grainyhead gene Get1/Grhl3 also regulates urothelial differentiation.
Specimen part
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