STEAP4 is a plasma membrane metallo-reductase involved in the transport of iron and copper. Recently, STEAP4 was implicated in promoting insulin sensitivity by acting in white adipose tissue (WAT) to control the production of inflammatory cytokines such as IL-6. Indeed, the loss of STEAP4 expression in mice leads to increased production of inflammatory cytokines in visceral WAT and systemic insulin resistance. In this report, we demonstrate that in mouse liver STEAP4 is produced at significant levels and that STEAP4 transcription is induced by IL-6. We further demonstrate that the STEAP4 gene is a direct target of phosphorylated STAT3 in mouse liver. In addition, hepatic STEAP4 expression is regulated by feeding and fasting, and obesity leads to the induction of STEAP4 expression in the liver. Interestingly, the regulation of STEAP4 in both feeding and fasting and the obese state appears to require the transcription factor C/EBPalpha that may act in concert with STAT3 as they both bind to the proximal STEAP4 promoter in vivo. Taken together these data suggest the transcriptional regulation of hepatic STEAP4 may play a critical role in the response to nutritional and inflammatory stress and contribute to the protective effect of STEAP4 in vivo.
Regulation of hepatic six transmembrane epithelial antigen of prostate 4 (STEAP4) expression by STAT3 and CCAAT/enhancer-binding protein alpha.
Sex, Specimen part
View SamplesNCoR1 (Nuclear receptor Co-Repressor) and SMRT (Silencing Mediator of Retinoid and Thyroid hormone receptor) are well-recognized coregulators of nuclear receptor (NR) action. However, their unique roles in the regulation of thyroid hormone (TH) signaling in specific cell types have not been determined. To accomplish this we generated a mouse model that lacked function of either NCoR1 or SMRT or both in the liver only. Despite both corepressors being present in the liver, SMRT had no ability to regulate TH signaling when deleted in either euthyroid or hypothyroid animals. In contrast, disruption of NCoR1 action confirmed that it is the principal mediator of TH sensitivity in vivo. While SMRT played little role in TH signaling alone, when disrupted in combination with NCoR1 it greatly accentuated the activation of hepatic lipogenesis regulated by NCoR1. Thus, corepressor specificity exists in vivo and NCoR1 is the principal regulator of TH action in the liver. However, both NCoR1 and SMRT collaborate to control hepatic lipogenesis and lipid storage, which likely reflects their cooperative activity in regulating the action of multiple NRs including the thyroid hormone receptor (TR).
NCoR1 and SMRT play unique roles in thyroid hormone action in vivo.
Sex, Specimen part
View SamplesThe thyroid hormone receptor (TR) has been proposed to regulate target genes in the absence of triiodothyronine (T3), through the recruitment of the corepressors, NCoR and SMRT. NCoR and SMRT may thus play a key role in both hypothyroidism and resistance to thyroid hormone, though this has never been tested in vivo. To accomplish this we developed mice that express in the liver a NCoR protein (L-NCoRID) that cannot interact with the TR. L-NCoRID mice develop normally, however when made hypothyroid the repression of many positively regulated T3-target genes is abrogated, demonstrating that NCoR plays a specific and sufficient role in repression by the unliganded TR. Remarkably, in the euthyroid state, expression of many T3-targets are also upregulated in L-NCoRID mice, demonstrating that NCoR also determines the magnitude of the response to T3 in euthyroid animals. While positive T3 targets were upregulated in L-NCoRID mice in the hypo and euthyroid state there was less effect seen on negatively regulated T3 target genes. Thus, NCoR is a specific regulator of T3-action in vivo and mediates the activity of the unliganded TR. Furthermore, NCoR may play a key role in determining the differences in individual responses to similar levels of circulating T3.
The nuclear corepressor, NCoR, regulates thyroid hormone action in vivo.
No sample metadata fields
View SamplesWe over-expressed biotinylated-thyroid hormone receptor beta 1 (TRb1) in mouse liver using an adenovirus in order to perform ChIP-seq experiments. These microarrays were performed to determine gene expression changes in response to tri-iodothyronine (thyroid hormone; T3) stimulation. A control GFP adenovirus was used and gene expression from these livers was also done as a comparison.
Novel mechanism of positive versus negative regulation by thyroid hormone receptor β1 (TRβ1) identified by genome-wide profiling of binding sites in mouse liver.
Specimen part, Treatment
View SamplesThe in vitro directed differentiation of pluripotent stem cells (PSCs) through stimulation of developmental signaling pathways can generate mature somatic cell types for basic laboratory studies or regenerative therapies.
Pluripotent stem cell differentiation reveals distinct developmental pathways regulating lung- versus thyroid-lineage specification.
Treatment
View SamplesARC (NSC 188491, SMA-491), 4-amino-6-hydrazino-7-beta-d-ribofuranosyl-7H-pyrrolo-(2,3-d)-pyrimidine-5-carboxamide, is a nucleoside analog with profound in vitro anti-cancer activity. First identified in a high-throughput screen for inhibitors of p21 mRNA expression, subsequent experiments showed that ARC also repressed expression of hdm2 and survivin, leading to its classification as a global inhibitor of transcription 1. The following Hu U133 plus 2.0 arrays represent single time point (24 hour) gene expression analysis of transcripts altered by ARC treatment. Arrays for the other compounds (sangivamycin and doxorubicin) are included as comparators.
ARC (NSC 188491) has identical activity to Sangivamycin (NSC 65346) including inhibition of both P-TEFb and PKC.
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View SamplesETS1 and RAS/ERK regulate a common gene expression program in establishing enviroment suitable for prostate cancer cell migration. Overall design: mRNA profiles of luciferase knockdown (WT), ETS1 knockdown, and U0126 treated DU145 cells were generated using deep sequencing, in triplicate, using Illumina HiSeq. Knockdowns were stable shRNA expression from a lentiviral construct selected with puromycin.
Interaction with ZMYND11 mediates opposing roles of Ras-responsive transcription factors ETS1 and ETS2.
No sample metadata fields
View SamplesGene expression analysis under normal culture conditions (RPMI-10%FBS) and at optimal cell densities.
Low-risk susceptibility alleles in 40 human breast cancer cell lines.
Cell line
View SamplesSAMHD1 restricts HIV-1 replication in dendritic and other myeloid cells. SAMHD1 has been shown to possess a dGTP-dependent dNTP triphosphatase (dNTPase) activity and is proposed to inhibit HIV-1 replication by depleting the intracellular dNTP pool. Arguing against a role for SAMHD1 dNTPase in HIV-1 restriction, the phosphorylation of SAMHD1 regulates the restriction activity toward HIV-1 without affecting its ability to decrease cellular dNTP levels. Here, we show that SAMHD1 is a phospho-regulated RNase and that the RNase function is required for HIV-1 restriction. Mutation of the SAMHD1 D137 residue in the allosteric site (SAMHD1D137N) abolishes dNTPase activity but has no effect on RNase activity. This dNTPase-defective SAMHD1D137N mutant is able to restrict HIV-1 infection to nearly the same extent as wild-type SAMHD1. SAMHD1 associates with and degrades the HIV-1 genomic RNA during the early phases of infection. SAMHD1 silencing in macrophages and CD4+ T cells from healthy donors increases HIV-1 RNA stability, thus rendering the cells permissive for HIV-1 infection. Furthermore, the phosphorylation of SAMHD1 at position T592 abolishes the RNase activity toward HIV-1 RNA, and consequently the ability of SAMHD1 to restrict HIV-1 infection, uncovering the phosphorylation of SAMHD1 T592 as a negative regulatory mechanism of RNase activity. Together, our results demonstrate that SAMHD1 is an essential RNase that prevents HIV-1 infection by directly degrading HIV-1 genomic RNA in a phosphorylation-regulated manner. The unique property of SAMHD1 that cleaves HIV-1 genomic RNA with no sequence preferences could be exploited to develop a new class of intervention for error-prone retroviruses. Overall design: Ribosomal RNA-depleted total RNA profiles of mock, SAMHD1 wild type and mutants infected with HIV-1 were examined at the time of 0, 1, 3 h by Illumina Hiseq2500.
The ribonuclease activity of SAMHD1 is required for HIV-1 restriction.
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View SamplesKnockdowns of c-JUN and JUND had opposite effects on PC3 prostate cell migration. We predicted that c-JUN and JUND control the same set of cell migration genes, but in opposite directions. To test this hypothesis, mRNA with expression changes in c-JUN and JUND knockdown PC3 cell lines were compared to mRNA levels in control (luciferase knockdown) PC3 cells by RNA-seq. Overall design: mRNA profiles of luciferase knockdown (WT), c-Jun knockdown, and Jun-D knockdown in PC3 cells were generated using deep sequencing, in triplicate, using Illumina HiSeq. Knockdowns were stable shRNA expression from a lentiviral construct selected with puromycin.
Extracellular signal-regulated kinase signaling regulates the opposing roles of JUN family transcription factors at ETS/AP-1 sites and in cell migration.
No sample metadata fields
View Samples