Thyroid hormone receptor is essential for larval eptiehlial apoptosis and adult epithelial stem cell development
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ABSTRACT:
ORGANISM(S): Xenopus tropicalis
PROVIDER: GSE161714 | GEO | 2021/03/31
REPOSITORIES: GEO
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Project description:Thyroid hormone receptor is essential for larval eptiehlial apoptosis and adult epithelial stem cell development
| PRJNA679241 | ENA
Project description:Our study represents the first detailed analysis of thyroid hormone binding to the genome in the intestine of wild-type and TRα (-/-) tadpoles, with biological replicates, generated by ChIP-seq technology. The optimized data analysis workflows reported here should provide a framework for comparative investigations of TR binding profiles.
2022-07-19 | GSE161718 | GEO
Project description:Thyroid hormone (TH) and TH receptors (TRs) α and β act by binding to TH response elements (TREs) in regulatory regions of target genes. This nuclear signaling is established as the canonical pathway for TH action. In addition, however, TRs can activate intra-cellular second messenger signaling pathways. Whether such non-canonical TR signaling is physiologically relevant in vivo is unknown. Here we generated knock-in mice with a mutation in the TR DNA-binding domain that abrogates binding to DNA and TREs and leads to a complete loss of canonical TH action. We show that several important physiological TH effects are preserved despite disrupted DNA-binding, most notably heart rate, body temperature, blood glucose and triglyceride concentration, all of which were regulated by non-canonical TR signaling. Additionally, we confirm that TRE-binding defective TRβ leads to disruption of the hypothalamic-pituitary-thyroid axis with resistance to TH, while mutation of TRα causes a severe delay in skeletal development, showing TRE-mediated and tissue-specific canonical signaling. Our findings provide first in vivo evidence that non-canonical TR signaling exerts important cardiometabolic effects, which are clearly separated from canonical actions. Consequently, these data challenge the current paradigm that TH action is exclusively mediated through regulation of gene transcription at the nuclear level.
2017-11-01 | GSE104877 | GEO
Project description:Objective: Thyroid hormone receptors (TRs) are ligand-dependent transcription factors with a major impact on erythroid cell development. Here we investigated TR activity on red cell gene expression and identified TR target genes. The impact of the TR target gene GAR22 (growth arrest specific 2 [GAS2]-related gene on chromosome 22) on red cell differentiation was determined. Methods: SCF/Epo dependent red cell progenitors were differentiated in vitro in the presence or absence of thyroid hormone. Hormone-induced changes in gene expression were measured by a genome-wide approach with DNA microarrays. Ectopic expression of the TR target gene GAR22 was used to determine its impact on red cell differentiation. Results: Ligand-activated TR effectively accelerated red cell progenitor differentiation in-vitro concomitantly with inducing growth arrest. We demonstrate that activated TR induced specific gene expression patterns of up- or down-regulated genes, including distinct clusters associated with accelerated differentiation in response to treatment. Mining for T3 induced genes identified BTEB1 (basic transcription element binding protein 1/Krüppel-like factor 9) and GAR22 as TR target genes. BTEB1/KLF9 is a known TR target gene while GAR22, initially identified as a putative tumor suppressor, represents a novel TR target gene. We demonstrate that ectopic GAR22 expression in red cell progenitors lengthens the cell cycle and causes growth inhibition, but leaves red cell gene expression unaffected. Conclusion: This study identifies GAR22 as a novel and direct TR target gene. Our results suggest that hormone-induced GAR22 might represent an important trigger of growth inhibition induced by thyroid hormone in red cell progenitors.
2008-07-31 | GSE7579 | GEO
Project description:Hormone dependent activation of enhancers includes histone hyperacetylation and mediator recruitment. Histone hyperacetylation is often explained by a bimodal switch mod-el, where histone deacetylases (HDACs) disassociates from chromatin and histone acetyl transferases (HATs) are recruited. This model builds on decades of research on steroid re-ceptor regulation of transcription. We have used a genomics approach to study enhancer hyperacetylation by the thyroid hormone receptor (TR) and present a revised model. 1) at poised constitutively TR bound enhancers, HATs occupy chromatin irrespective of thyroid hormone (T3) levels, whereas HDAC occupancy is regulated by T3, suggesting that HDACs functions as a histone acetylation rheostat. 2) at enhancers established in a T3 dependent manner, TR is recruited to chromatin together with HATs. 3) a number of enhancers are hy-peracetylated secondary to TR activation. Collectively, this demonstrates various mechanisms controlling hormone dependent transcription and adds significant details to the otherwise simple bimodal switch model.
2019-07-01 | GSE128535 | GEO
Project description:Drosophila adult blood cells originate from larval peripheral hemocytes (derived from the embryonic waves of hematopoiesis) and from larval lymph gland hemocytes. To gain insight into the expression repertoire of Drosophila blood cells, we established the gene expression profiles the adult blood cells and their ascendants.
2021-09-28 | GSE174107 | GEO
Project description:This study aims to characterize the larval shell proteome of the blue mussel for the first time and to compare it to adult mussel shell proteomes
2022-03-17 | PXD013675 | Pride
Project description:The obesity epidemic is a significant global health issue. Improved understanding of the mechanisms which regulate appetite and body weight will provide the rationale for the design of novel anti-obesity therapies. Thyroid hormones play a key role in metabolic homeostasis through their interaction with thyroid hormone receptors (TR) which function as ligand inducible transcription factors. The TR beta isoform (TRβ) is expressed in the ventromedial hypothalamus (VMH), a brain area important for control of energy homeostasis. Here we report that selective knock down of TRβ in the VMH of adult mice results in severe obesity due to hyperphagia and reduced energy expenditure. The observed increase in body weight is of a similar magnitude to murine models of the most extreme forms of monogenic obesity. These data identify TRβ in the VMH as a major physiological regulator of food intake and energy homeostasis.
2017-06-01 | GSE98690 | GEO
Project description:Thyroid hormones (TH) are powerful regulators of metabolism with major effects on body weight, cholesterol, and liver fat that have been exploited pharmacologically for many years. Activation of gene expression by TH action is canonically ascribed to a hormone- dependent “switch” from corepressor to activator binding to thyroid hormone receptors (TR), while the mechanism of TH-dependent repression is controversial. To address this, we generated a mouse line in which endogenous TRβ1 was epitope-tagged to allow precise chromatin immunoprecipitation at the low physiological levels of TR, and defined high confidence binding sites where TR functioned at enhancers regulated in the same direction as the nearest gene in a TRβ-dependent manner. Remarkably, although positive and negative regulation by TH have been ascribed to different mechanisms, TR binding was highly enriched at canonical DR4 motifs irrespective of the transcriptional direction of the enhancer. The canonical NCoR1/HDAC3 corepressor complex was reduced but not completely dismissed by TH and, surprisingly, similar effects were seen at enhancers associated with negatively as well as positively regulated genes. Conversely, coactivator CBP was found at all TH-regulated enhancers, with transcriptional activity correlating with the ratio of CBP to NCoR rather than their presence or absence. These results demonstrate that, in contrast to the canonical “all or none” coregulator switch model, TH regulates gene expression by orchestrating a shift in the relative binding of corepressors and coactivators.
2021-01-01 | GSE159648 | GEO
Project description:High throughput in vitro, in silico, and computational approaches have identified numerous environmental chemicals that interfere with thyroid hormone (TH) activity, and it is posited that human exposures to such chemicals are a contributing factor to neurodevelopmental disorders. However, whether hits in screens of TH activity are predictive of developmental neurotoxicity (DNT) has yet to be systematically addressed. The zebrafish has been proposed as a second tier model for assessing the in vivo DNT potential of TH active chemicals. As an initial evaluation of the feasibility of this proposal, we determined whether an endpoint often used to assess DNT in larval zebrafish, specifically photomotor behavior, is altered by experimentally induced hyper- and hypothyroidism. Developmental hyperthyroidism was simulated by static waterborne exposure of zebrafish to varying concentrations (3-300?nM) of thyroxine (T4) or triiodothyronine (T3) beginning at 6?h post-fertilization (hpf) and continuing through 5 days post-fertilization (dpf). Teratogenic effects and lethality were observed at 4 and 5 dpf in fish exposed to T4 or T3 at concentrations >30 nM. However, as early as 3 dpf, T4 (> 3 nM) and T3 (> 10 nM) significantly increased swimming activity triggered by sudden changes from light to dark, particularly during the second dark period (Dark 2). Conversely, developmental hypothyroidism, which was induced by treatment with 6-propyl-2-thiouracil (PTU), morpholino knockdown of the TH transporter mct8, or ablation of thyroid follicles in adult females prior to spawning, generally decreased swimming activity during dark periods, although effects did vary across test days. All effects of developmental hypothyroidism on photomotor behavior occurred independent of teratogenic effects and were most robust during Dark 2. Treatment with the T4 analog, Tetrac, restored photomotor response in mct8 morphants to control levels. Collectively, these findings suggest that while the sensitivity of photomotor behavior in larval zebrafish to detect TH disruption is influenced by test parameters, this test can distinguish between TH promoting and TH blocking activity and may be useful for assessing the DNT potential of TH-active chemicals.
| S-EPMC6750994 | biostudies-literature