Unknown,Transcriptomics,Genomics,Proteomics

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Rat hypothalamus: Methimazole (MMI)-saline vs MMI-T3

ABSTRACT: Sprague Dawley rats rendered hypothyroid with 22 days of MMI treatment with half the receiving T3 injection on day 21. Rats killed 24h later and hypothalamic tissue recovered. Two condition experiment MMI vs MMI-T3 hypothalami 4 replicates per treatment

ORGANISM(S): Rattus norvegicus

SUBMITTER: Perry Barrett

PROVIDER: E-GEOD-55803 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Project description:Transcriptional profiling of rat liver comparing male rats with congenital hypothyrodism (CH) vs intact at adulhood. Here we studied how CH influences liver gene expression program in adulthood. Thyroid hormones are required for normal growth and development in mammals. Congenital-neonatal hypothyroidism (CH) has a profound impact on physiology but its specific influence in liver is less understood. Here we studied how CH influences liver gene expression program in adulthood. Pregnant rats were given anti-thyroid drug methimazole (MMI) from GD12 until PND30 to induce CH in male offspring. Growth defects due to CH were evident as a reduction in body weight and tail length from the second week of life. Once the MMI treatment was discontinued, feed efficiency increased in CH and this was accompanied by significant catch-up growth. On PND80, significant reduction in body mass, tail length, and circulating IGF-I remained in CH rats. On the other hand, mRNA levels of known GH targeted genes were significantly up-regulated. Serum levels of thyroid hormones, cholesterol, and triglycerides showed no significant differences. In contrast, CH rats showed significant changes in expression for hepatic genes involved in lipid metabolism with an increased transcription of PPAR and reduced expression of genes involved in fatty acids and cholesterol uptake, cellular sterol efflux, triglycerides assembly, bile acid synthesis, and lipogenesis. These changes were associated with a decrease of intrahepatic lipids. Finally, CH rats responded to hypothyroidism onset in adulthood with a reduction of serum fatty acids and hepatic cholesteryl esters, and to T3 replacement with enhanced activation of lipogenic transcriptional program. In summary, we provided in vivo evidence that neonatal hypothyroidism causes long-lasting effects on hepatic transcriptional program and tissue sensitivity to hormone treatment. This highlights the critical role that a euthyroid state during development plays on normal liver physiology in adulthood. Two conditions CH vs INTACT male rats. Biological replicates: Four independent hybridizations: 4 controls (age-matched intact rats) vs 4 CH (male rats with congenital hypothyroidism) on postnatal day 80 for a total of four arrays. One replicate per array.

Project description:E2 and GH are critical regulators of growth and intermediate metabolism in mammals. Hypothyroidism causes endocrine and metabolic disturbances in the liver with features that mimic deficiencies of E2 or GH signalling. In this work, we used the hypothyroid-orchiectomized (TXOX) adult rat model to evaluate the influence of E2 and GH on the liver in terms of global changes in gene expression. This study shows the changes in hepatic transcriptome that were provoked by E2 benzoate (50 ug/kg; sc; 5 days per week x 27 days), intermittent GH administration (0.3 mg/kg/day;sc injection divided into two daily injections x 7 days) or the combination of E2 plus GH in TXOX rats. E2 influenced the liver transcriptome, particularly genes involved in metabolism of lipids and endo-xenobiotics, and the GH-regulated endocrine, metabolic, gender, and immune responses. E2 did not prevent the inhibitory effects of GH on urea and amino acid metabolism-related genes. Notably, the combination of E2 and GH caused deleterious effects on transcriptional immune response. These results highlight the role of E2 as a critical regulator of liver metabolism in mammals and provide insights into the functional interplay between E2 and GH in the liver. Groups=4; Biological replicates = 4 per group; Samples=16; Reference samples=TXOX group. Adult (3 months old) male Sprague-Dawley rats (n=4 per group) were used throughout these experiments. The generation of TXOX was performed by adding methimazole (MMI; 0.05%) to the drinking water for 5 weeks starting on postnatal day (PND) 59 until sacrifice on PND94. Two weeks after starting MMI administration, male rats were castrated (OX) to make TXOX rats. Four days after OX, we began treatment with E2 benzoate (TXOXE2) or vehicle (TXOX) to TXOX rats for 20 days followed for 7 days by either vehicle plus GH (TXOXGH) or by E2 plus GH (TXOXE2GH). Twenty-four hours (in the case of E2) or twelve hours (in the case of GH) after the last injection, the animals were killed by exsanguinations. Portions of the liver were snap frozen in liquid nitrogen and stored at -80C until processed for mRNA analysis.

Project description:Synthetic selective thyroid hormone (TH) receptor (TR) modulators (STRMs) exhibit beneficial effects on dyslipidemias in animals and humans and reduce obesity, fatty liver and insulin resistance in preclinical animal models. STRMs differ from native THs in preferential binding to the TRβ subtype versus TRα, increased uptake into liver and reduced uptake into other tissues. However, selective modulators of other nuclear receptors (NRs) exhibit important gene-selective actions which have been attributed to differential effects on receptor conformation and dynamics and these effects can have profound influences in animals and humans. While there are suggestions that STRMs could exhibit such gene-specific actions, the extent to which these effects are actually observed in vivo has not been explored. Here, we show that saturating concentrations of the main active form of TH, triiodothyronine (T3), and the prototype STRM GC-1 induce identical gene-sets in livers of euthyroid and hypothyroid mice and a human cultured hepatoma cell line that only expresses TRβ, HepG2. We find one case in which GC-1 exhibits a modest gene-specific reduction in potency versus T3, at angiopoietin-like factor 4 (ANGPTL4) in HepG2. Investigation of the latter effect confirms that GC-1 acts through TRβ to directly induce this gene. However, this gene-selective GC-1 activity is not related to unusual T3 response element (TRE) sequence, unlike previously documented promoter-selective STRM actions. Together, our data suggest that T3 and GC-1 exhibit almost identical gene regulation properties and that gene-selective actions of GC-1 and similar STRMs will be subtle and rare. We treated HepG2 with vehicle or 10nM ligand (T3 or GC1; n=3 / treatment), analyzing mRNA 24h post treatment [Affymetrix]. We also treated 9-week old euthyroid male C57/Bl6 mice with vehicle or ligand (T3 or GC-1) by a single oral gavage (n=5 per treatment) and also performed a similar study in which mice were first made hypothyroid by two week feeding on iodine deficient diet (n=3-4 per treatment), analyzing mRNA 24h post treatment [Illumina].

Project description:Synthetic selective thyroid hormone (TH) receptor (TR) modulators (STRMs) exhibit beneficial effects on dyslipidemias in animals and humans and reduce obesity, fatty liver and insulin resistance in preclinical animal models. STRMs differ from native THs in preferential binding to the TR? subtype versus TR?, increased uptake into liver and reduced uptake into other tissues. However, selective modulators of other nuclear receptors (NRs) exhibit important gene-selective actions which have been attributed to differential effects on receptor conformation and dynamics and these effects can have profound influences in animals and humans. While there are suggestions that STRMs could exhibit such gene-specific actions, the extent to which these effects are actually observed in vivo has not been explored. Here, we show that saturating concentrations of the main active form of TH, triiodothyronine (T3), and the prototype STRM GC-1 induce identical gene-sets in livers of euthyroid and hypothyroid mice and a human cultured hepatoma cell line that only expresses TR?, HepG2. We find one case in which GC-1 exhibits a modest gene-specific reduction in potency versus T3, at angiopoietin-like factor 4 (ANGPTL4) in HepG2. Investigation of the latter effect confirms that GC-1 acts through TR? to directly induce this gene. However, this gene-selective GC-1 activity is not related to unusual T3 response element (TRE) sequence, unlike previously documented promoter-selective STRM actions. Together, our data suggest that T3 and GC-1 exhibit almost identical gene regulation properties and that gene-selective actions of GC-1 and similar STRMs will be subtle and rare. We treated 9-week old euthyroid male C57/Bl6 mice with vehicle or ligand (T3 or GC-1) by a single oral gavage (n=5 per treatment) and also performed a similar study in which mice were first made hypothyroid by two week feeding on iodine deficient diet (n=3-4 per treatment), analyzing mRNA 24h post treatment [Illumina]. We also treated HepG2 with vehicle or 10nM ligand (T3 or GC1; n=3 / treatment), analyzing mRNA 24h post treatment [Affymetrix].

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Rat hypothalamus: Methimazole (MMI)-saline vs MMI-T3

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