Purpose: The objective of this study was to determine cardiac transcriptional pathways regulated in response to 1.) hypothyroidism and re-establishment of a euthyroid state and 2.) Med13-dependent cardiac transcriptional pathways regulated in response to hypothyroidism and re-establishment of a euthyroid state Overall design: Methods: WT and Med13 cardiac-specific knockout mice (Med13cKO) were put on a normal chow or PTU diet at 8 weeks of age for a duration of 4 weeks. A third group was put on a PTU diet for 4 weeks followed by 3 daily injections of T3.
Regulation of cardiac transcription by thyroid hormone and Med13.
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View SamplesAnalysis of ventricular derived mRNA from Med1fl/fl and Med1fl/fl cardiac knockout mice. Results provide insight into the molecual rmechanisms underlying dilated cardiomyopathy. Overall design: Methods: Ventricular samples (4 per group) from 21-day-old Med1fl/fl and Med1 cardiac knockout mice were used to generate polyA enriched stranded RNA libraries followed by RNAseq using the Illumina HiSeq platform. Raw sequence reads were analyzed with BaseSpace (www.illumina.com) by aligning reads to the mus musculus mm10 genome using the TopHat Alignment app. Transcripts were assembled and significant differentially expressed genes were determined with the Cufflinks Assembly and DE app using a false discovery rate <0.05. qRT–PCR validation was performed using SYBR Green assays
Cardiac Med1 deletion promotes early lethality, cardiac remodeling, and transcriptional reprogramming.
Specimen part, Subject
View SamplesLeanness is associated with increased lifespan and is linked to favorable metabolic conditions promoting life extension.
Deficiency of the lipid synthesis enzyme, DGAT1, extends longevity in mice.
Sex, Specimen part
View SamplesThe heart requires a continuous supply of energy but has little capacity for energy storage and thus relies on exogenous metabolic sources. We previously showed that cardiac MED13 modulates systemic energy homeostasis in mice. Here we sought to define the extra-cardiac tissue(s) that respond to cardiac MED13 signaling. We show that cardiac over-expression of MED13 in transgenic (MED13cTg) mice confers a lean phenotype that is associated with increased lipid uptake, beta-oxidation and mitochondrial content in white adipose tissue (WAT) and liver. Cardiac expression of MED13 decreases metabolic gene expression and metabolite levels in heart and liver but enhances them in WAT. Although exhibiting increased energy expenditure in the fed state, MED13cTg mice metabolically adapt to fasting. Furthermore, MED13cTg hearts oxidize fuel that is readily available, rendering them more efficient in the fed state. Parabiosis experiments in which circulations of wild-type and MED13cTg mice are joined, reveal that circulating factor(s) in MED13cTg mice promote enhanced metabolism and leanness. These findings demonstrate that MED13 acts within the heart to promote systemic energy expenditure in extra-cardiac energy depots and point to an unexplored metabolic communication system between the heart and other tissues. Overall design: n=3 for each genotype and organ
MED13-dependent signaling from the heart confers leanness by enhancing metabolism in adipose tissue and liver.
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View SamplesWe assessed the impact of glucose transporter Glut2 gene inactivation in adult mouse liver (LG2KO mice). This suppressed hepatic glucose uptake but not glucose output. In the fasted state, expression of carbohydrate responsive element-binding protein (ChREBP) and its glycolytic and lipogenic target genes was abnormally elevated. Feeding, energy expenditure, and insulin sensitivity were identical in LG2KO and control mice. Glucose tolerance was normal early after Glut2 inactivation but intolerance developed at later time. This was caused by progressive impairment of glucose-stimulated insulin secretion even though beta-cell mass and insulin content remained normal. Liver transcript profiling revealed a coordinate down-regulation of cholesterol biosynthesis genes in LG2KO mice. This was associated with reduced hepatic cholesterol in fasted mice and a 30 percent reduction in bile acid production. We showed that chronic bile acids or FXR agonist treatment of primary islets increases glucose-stimulated insulin secretion, an effect not seen in islets from fxr-/- mice. Collectively, our data show that glucose sensing by the liver controls beta-cell glucose competence, through a mechanism that likely depends on bile acid production and action on beta-cells.
Hepatic glucose sensing is required to preserve β cell glucose competence.
Specimen part
View SamplesSIRT3 is a mitochondrial NAD(+)-dependent protein deacetylase, which regulates the enzymatic activity of several mitochondrial proteins.
SIRT3 deficiency and mitochondrial protein hyperacetylation accelerate the development of the metabolic syndrome.
Age, Specimen part
View SamplesGene expression analysis of primary mouse prostate organoid culture with overexpression of FOXA1 Overall design: Examination by genotypes and days elapsed prepared in 3 replicates
FOXA1 mutations alter pioneering activity, differentiation and prostate cancer phenotypes.
Subject, Time
View SamplesCell-cell communication is critical for stem cell maintenance. Shoot apical meristem (SAM) located at the shoot tip harbors stem cells within the central zone (CZ). Their progeny differentiate in the adjacent peripheral zone (PZ). WUSCHEL (WUS) is a homeodomain transcription factor produced in a few cells of the organizing center (OC), located beneath the CZ. It has been shown to specify stem cell fate and also activate CLAVATA3 (CLV3) expression in cells of the CZ. CLV3 is a secreted peptide that activates a membrane bound receptor kinase-CLAVATA1 to restrict WUS transcription to the OC. It has been hypothesized that WUS activates CLV3 expression and stem cell fate in adjacent cells of the CZ by activating a non-cell autonomous signal. Contrary to this hypothesis, here we show that the WUS protein after being synthesized in cells of the OC, migrates into the superficial cell layers of the CZ where it activates CLV3 transcription by binding to its promoter elements. WUS also migrates laterally into the PZ to repress the expression of differentiation promoting transcription factors by binding to their regulatory regions. Migration of a stem cell inducing transcription factor into adjacent cells to activate a negative regulator, whereby restricting its own accumulation is unique to plant stem cell niches. While stem cell promoting transcription factor directly repressing differentiation promoting transcription factors to prevent premature differentiation of stem cell progenitors is conserved among diverse stem cell niches.
Plant stem cell maintenance involves direct transcriptional repression of differentiation program.
Treatment
View SamplesHuman transcripts can typically be processed at multiple polyadenylation sites to yield mRNA isoforms with distinct 3 ends. A multitude of factors contributes to the choice of individual polyadenylation sites in different cell types and tissues. In this study we have found that the heterogenous ribonucleoprotein C (hnRNP C), an RNA binding protein that was previously linked to splicing and polyadenylation at Alu repeat elements, is a general regulator of pre-mRNA cleavage and polyadenylation. By sequencing mRNA 3 ends from cells expressing normal and reduced levels of hnRNP C we found that transcripts that contain poly(U) tracts around their poly(A) sites respond in a manner indicative of hnRNP C repressing cleavage and polyadenylation. The 3 UTR isoforms whose abundance is modulated by hnRNP C contain U-rich elements and can thereby interact with A/U-rich element binding proteins that have been shown to alter transcript stability, sub-cellular localization and even the localization of the translated proteins.
A comprehensive analysis of 3' end sequencing data sets reveals novel polyadenylation signals and the repressive role of heterogeneous ribonucleoprotein C on cleavage and polyadenylation.
No sample metadata fields
View SamplesMicroarray Analysis of Space-flown Murine Thymus Tissue Reveals Changes in Gene Expression Regulating Stress and Glucocorticoid Receptors. We used microarrays to detail the gene expression of space-flown thymic tissue and identified distinct classes of up-regulated genes during this process. We report here microarray gene expression analysis in young adult C57BL/6NTac mice at 8 weeks of age after exposure to spaceflight aboard the space shuttle (STS-118) for a period of 13 days. Upon conclusion of the mission, thymus lobes were extracted from space flown mice (FLT) as well as age- and sex-matched ground control mice similarly housed in animal enclosure modules (AEM). mRNA was extracted and an automated array analysis for gene expression was performed. Examination of the microarray data revealed 970 individual probes that had a 1.5 fold or greater change. When these data were averaged (n=4), we identified 12 genes that were significantly up- or down-regulated by at least 1.5 fold after spaceflight (p0.05). Together, these data demonstrate that spaceflight induces significant changes in the thymic mRNA expression of genes that regulate stress, glucocorticoid receptor metabolism, and T cell signaling activity. These data explain, in part, the reported systemic compromise of the immune system after exposure to the microgravity of space.
Microarray analysis of spaceflown murine thymus tissue reveals changes in gene expression regulating stress and glucocorticoid receptors.
Specimen part
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