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Selenoprotein gene expression in thyroid and pituitary of young pigs is not affected by dietary selenium deficiency or excess.

ABSTRACT: Expression and function of selenoproteins in endocrine tissues remain unclear, largely due to limited sample availability. Pigs have a greater metabolic similarity and tissue size than rodents as a model of humans for that purpose. We conducted 2 experiments: 1) we cloned 5 novel porcine selenoprotein genes; and 2) we compared the effects of dietary selenium (Se) on mRNA levels of 12 selenoproteins, activities of 4 antioxidant enzymes, and Se concentrations in testis, thyroid, and pituitary with those in liver of pigs. In Experiment 1, porcine Gpx2, Sephs2, Sep15, Sepn1, and Sepp1 were cloned and demonstrated 84-94% of coding sequence homology to human genes. In Experiment 2, weanling male pigs (n = 30) were fed a Se-deficient (0.02 mg Se/kg) diet added with 0, 0.3, or 3.0 mg Se/kg as Se-enriched yeast for 8 wk. Although dietary Se resulted in dose-dependent increases (P < 0.05) in Se concentrations and GPX activities in all 4 tissues, it did not affect the mRNA levels of any selenoprotein gene in thyroid or pituitary. Testis mRNA levels of Txnrd1 and Sep15 were decreased (P < 0.05) by increasing dietary Se from 0.3 to 3.0 mg/kg. Comparatively, expressions of Gpx2, Gpx4, Dio3, and Sep15 were high in pituitary and Dio1, Sepp1, Sephs2, and Gpx1 were high in liver. In conclusion, the mRNA abundances of the 12 selenoprotein genes in thyroid and pituitary of young pigs were resistant to dietary Se deficiency or excess.

SUBMITTER: Zhou JC

PROVIDER: S-EPMC3738374 | biostudies-literature | 2009 Jun

REPOSITORIES: biostudies-literature

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Selenoprotein gene expression in thyroid and pituitary of young pigs is not affected by dietary selenium deficiency or excess.

Zhou Ji-Chang JC Zhao Hua H Li Jun-Gang JG Xia Xin-Jie XJ Wang Kang-Ning KN Zhang Ya-Jun YJ Liu Yan Y Zhao Ying Y Lei Xin Gen XG

The Journal of nutrition 20090408 6

Expression and function of selenoproteins in endocrine tissues remain unclear, largely due to limited sample availability. Pigs have a greater metabolic similarity and tissue size than rodents as a model of humans for that purpose. We conducted 2 experiments: 1) we cloned 5 novel porcine selenoprotein genes; and 2) we compared the effects of dietary selenium (Se) on mRNA levels of 12 selenoproteins, activities of 4 antioxidant enzymes, and Se concentrations in testis, thyroid, and pituitary with ...[more]

PMID: 19357213

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Project description:BackgroundThe immune system is one aspect of health that is affected by dietary selenium (Se) levels and selenoprotein expression. Spleen is an important immune organ of the body, which is directly involved in cellular immunity. However, there are limited reports on Se levels and spleen health. Therefore, this study established a Se-deficient pig model to investigate the mechanism of Se deficiency-induced splenic pathogenesis.MethodsTwenty-four pure line castrated male Yorkshire pigs (45 days old, 12.50 ± 1.32 kg, 12 full-sibling pairs) were divided into two equal groups and fed Se-deficient diet (0.007 mg Se/kg) or Se-adequate diet (0.3 mg Se/kg) for 16 weeks. At the end of the trial, blood and spleen were collected to assay for erythroid parameters, the osmotic fragility of erythrocytes, the spleen index, histology, terminal deoxynucleotidyl transferase nick-end labeling (TUNEL) staining, Se concentrations, the selenogenome, redox status, and signaling related inflammation and apoptosis.ResultsDietary Se deficiency decreased the erythroid parameters and increased the number of osmotically fragile erythrocytes (P < 0.05). The spleen index did not change, but hematoxylin and eosin and TUNEL staining indicated that the white pulp decreased, the red pulp increased, and splenocyte apoptosis occurred in the Se deficient group. Se deficiency decreased the Se concentration and selenoprotein expression in the spleen (P < 0.05), blocked the glutathione and thioredoxin antioxidant systems, and led to redox imbalance. Se deficiency activated the NF-κB and HIF-1α transcription factors, thus increasing pro-inflammatory cytokines (IL-1β, IL-6, IL-8, IL-17, and TNF-α), decreasing anti-inflammatory cytokines (IL-10, IL-13, and TGF-β) and increasing expression of the downstream genes COX-2 and iNOS (P < 0.05), which in turn induced inflammation. In addition, Se-deficiency induced apoptosis through the mitochondrial pathway, upregulated apoptotic genes (Caspase3, Caspase8, and Bak), and downregulated antiapoptotic genes (Bcl-2) (P < 0.05) at the mRNA level, thus verifying the results of TUNEL staining.ConclusionsThese results indicated that Se deficiency induces spleen injury through the regulation of selenoproteins, oxidative stress, inflammation and apoptosis.

Project description:This study was envisaged to comprehensively profile genes in selected tissues along with a few biochemical indicators and integrate resulting information with dietary selenium (Se) deficiency symptoms in broilers. A total of 120 one-day-old Cobb male broilers were equally divided into two groups and fed a Se deficient corn-soybean-based basal diet supplemented with 0.3 mg/kg sodium selenite (Control, Se adequate) or without selenite (Se deficiency) for five weeks. Effects of Se deficiency on mRNA abundance of twenty-three selenoprotein encoding genes and seventeen insulin signaling related genes were studied at day 35 in pancreas, liver and muscle along with plasma biochemical constituents and enzyme activities. Compared to healthy birds in control diet, Se deficient diet induced deficiency symptoms in 90% birds and classic nutritional pancreatic atrophy, depressed growth performance of broilers, and decreased (P < 0.01 to P < 0.05) total antioxidant capacity and activities of superoxide dismutase and glutathione peroxidase in plasma and three other tissues. Se deficiency resulted in 58% higher mortality than control birds. Dietary Se deficiency down-regulated (P < 0.01-0.05) eighteen selenoprotein encoding genes in pancreas, fourteen genes in muscle and nine genes in liver, and up-regulated (P < 0.05) Txnrd1 and Selx in liver. Meanwhile, six, thirteen and five insulin signaling related genes were down-regulated (P < 0.01-0.05) in pancreas, muscle and liver, respectively, and three genes were up-regulated (P < 0.01) in liver. The decrease (P < 0.05) in levels of plasma insulin, total triglyceride and total cholesterol, and concurrent elevated (P < 0.05) levels of plasma glucose and inflammatory cytokines accompanied the global down-regulation of selenoprotein encoding- and insulin signaling related- genes in Se deficient birds. It was concluded that dietary Se deficiency induces nutritional pancreatic atrophy and metabolic disorder of glucose and lipid in broilers via down-regulation of selenoprotein encoding- and insulin signaling related- genes, indicating potential roles of these genes in metabolic regulation.

Project description:BackgroundA declining selenium (Se) status constitutes a characteristic of critical illness and may affect disease course and survival. The dynamics of trauma-induced changes in biomarkers of Se status are poorly characterized, and an association with multiple organ failure (MOF) and mortality can be hypothesized. It was the aim of this study to investigate Se and selenoprotein P (SELENOP) concentrations in major trauma patients during the early posttraumatic period.Patients and methodsTwenty-four patients after major trauma (ISS ≥16) were included at our level one trauma center. Se supplementation ever during the 90-day observation period was defined as an exclusion criterion. Serum samples were drawn within less than 60 min after trauma, and after 6 h, 12 h, 24 h, 48 h, and 72 h. Serum Se was analyzed by X-ray fluorescence and SELENOP concentrations by ELISA. The data were correlated to clinical parameters, occurrence of MOF defined by MOF and APACHE II score, lung injury defined by Horowitz index and clinical outcome (90-days survival).ResultsSerum Se and SELENOP concentrations of the trauma patients were significantly below the average of healthy European subjects (mean ±SD; Se, 41.2±8.1 vs. 84.7±23.3 μg/L, P < 0.001; SePP, 1.5±0.3 vs. 4.3±1.0 mg/L, P < 0.001). A strong deficit was present already at the first time point (Se; 33.6±10.5 μg/L, SELENOP: 1.4±0.5 mg/L). The clinical scores collectively showed an inverse relation between health status and Se biomarkers. Patients who did not survive the 90-day observation period exhibited significantly lower initial post-trauma Se status than the surviving patients (mean±SD; Se, 24.7±7.2 vs. 39.2±8.4 μg/L, P<0.05; SePP, 1.1±0.4 vs. 1.6±0.4 mg/L, P<0.05).ConclusionVery low Se and SELENOP concentrations occur fast after major trauma and are associated with poor survival odds. These findings support the notion that early Se substitution may constitute a meaningful adjuvant treatment strategy in trauma patients.

Project description:BackgroundRelations of the 25 mammalian selenoprotein genes with obesity and the associated inflammation remain unclear.ObjectiveThis study explored impacts of high-fat diet-induced obesity on inflammation and expressions of selenoprotein and obesity-related genes in 10 tissues of pigs.MethodsPlasma and 10 tissues were collected from pigs (n = 10) fed a corn-soy-based control diet or that diet containing 3-7% lard from weanling to finishing (180 d). Plasma concentrations (n = 8) of cytokines and thyroid hormones and tissue mRNA abundance (n = 4) of 25 selenoprotein genes and 16 obesity-related genes were compared between the pigs fed the control and high-fat diets. Stepwise regression was applied to analyze correlations among all these measures, including the previously reported body physical and plasma biochemical variables.ResultsThe high-fat diet elevated (P < 0.05) plasma concentrations of tumor necrosis factor α, interleukin-6, leptin, and leptin receptor by 29-42% and affected (P < 0.05-0.1) tissue mRNA levels of the selenoprotein and obesity-related genes in 3 patterns. Specifically, the high-fat diet up-regulated 12 selenoprotein genes in 6 tissues, down-regulated 13 selenoprotein genes in 7 tissues, and exerted no effect on 5 genes in any tissue. Body weights and plasma triglyceride concentrations of pigs showed the strongest regressions to tissue mRNA abundances of selenoprotein and obesity-related genes. Among the selenoprotein genes, selenoprotein V and I were ranked as the strongest independent variables for the regression of phenotypic and plasma measures. Meanwhile, agouti signaling protein, adiponectin, and resistin genes represented the strongest independent variables of the obesity-related genes for the regression of tissue selenoprotein mRNA.ConclusionsThe high-fat diet induced inflammation in pigs and affected their gene expression of selenoproteins associated with thioredoxin and oxidoreductase systems, local tissue thyroid hormone activity, endoplasmic reticulum protein degradation, and phosphorylation of lipids. This porcine model may be used to study interactive mechanisms between excess fat intake and selenoprotein function.

Dataset Information

Selenoprotein gene expression in thyroid and pituitary of young pigs is not affected by dietary selenium deficiency or excess.

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Selenoprotein gene expression in thyroid and pituitary of young pigs is not affected by dietary selenium deficiency or excess.

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