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Sample records for ahr activation alters

  1. Teratogenic impact of dioxin-activated AHR in laboratory animals

    EPA Science Inventory

    AHR and ARNT are expressed in mouse and human palatal shelves and in the urinary tract of the mouse fetus. AHR expression, translocation to the nucleus, binding to DRE, and activation are required for mediation of TCDD-induction of CP and HN. Although the human palate requires a ...

  2. An altered hydrotropic response (ahr1) mutant of Arabidopsis recovers root hydrotropism with cytokinin

    PubMed Central

    Saucedo, Manuel; Ponce, Georgina; Campos, María Eugenia; Eapen, Delfeena; García, Edith; Luján, Rosario; Sánchez, Yoloxóchitl; Cassab, Gladys I.

    2012-01-01

    Roots are highly plastic and can acclimate to heterogeneous and stressful conditions. However, there is little knowledge of the effect of moisture gradients on the mechanisms controlling root growth orientation and branching, and how this mechanism may help plants to avoid drought responses. The aim of this study was to isolate mutants of Arabidopsis thaliana with altered hydrotropic responses. Here, altered hydrotropic response 1 (ahr1), a semi-dominant allele segregating as a single gene mutation, was characterized. ahr1 directed the growth of its primary root towards the source of higher water availability and developed an extensive root system over time. This phenotype was intensified in the presence of abscisic acid and was not observed if ahr1 seedlings were grown in a water stress medium without a water potential gradient. In normal growth conditions, primary root growth and root branching of ahr1 were indistinguishable from those of the wild type (wt). The altered hydrotropic growth of ahr1 roots was confirmed when the water-rich source was placed at an angle of 45° from the gravity vector. In this system, roots of ahr1 seedlings grew downward and did not display hydrotropism; however, in the presence of cytokinins, they exhibited hydrotropism like those of the wt, indicating that cytokinins play a critical role in root hydrotropism. The ahr1 mutant represents a valuable genetic resource for the study of the effects of cytokinins in the differential growth of hydrotropism and control of lateral root formation during the hydrotropic response. PMID:22442413

  3. Aryl hydrocarbon receptor (AHR)-active pharmaceuticals are selective AHR modulators in MDA-MB-468 and BT474 breast cancer cells.

    PubMed

    Jin, Un-Ho; Lee, Syng-ook; Safe, Stephen

    2012-11-01

    Leflunomide, flutamide, nimodipine, mexiletine, sulindac, tranilast, 4-hydroxytamoxifen, and omeprazole are pharmaceuticals previously characterized as aryl hydrocarbon receptor (AHR) agonists in various cell lines and animal models. In this study, the eight AHR-active pharmaceuticals were investigated in highly aggressive aryl hydrocarbon (Ah)-responsive BT474 and MDA-MB-468 breast cancer cell lines, and their effects on AHR protein, CYP1A1 (protein and mRNA), CYP1B1 (mRNA), and cell migration were determined. 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) was used as a positive control. The AHR agonist activities of the pharmaceuticals depended on structure, response, and cell context. Most compounds induced one or more AHR-mediated responses in BT474 cells, whereas in Ah-responsive MDA-MB-468 cells effects of the AHR-active pharmaceuticals were highly variable. 4-Hydroxytamoxifen, mexiletine, and tranilast did not induce CYP1A1 in MDA-MB-468 cells; moreover, in combination with TCDD, mexiletine was a potent AHR antagonist, tranilast was a partial antagonist, and 4-hydroxytamoxifen also exhibited some AHR antagonist activity. Omeprazole and, to a lesser extent, sulindac and leflunomide were full and partial AHR agonists, respectively, in both breast cancer cell lines. These data indicate that the AHR-active pharmaceuticals are selective AHR modulators, and applications of these drugs for targeting the AHR must be confirmed by studies using the most relevant cell context. PMID:22879383

  4. Functional and phenotypic effects of AhR activation in inflammatory dendritic cells

    SciTech Connect

    Bankoti, Jaishree; Rase, Ben; Simones, Tom; Shepherd, David M.

    2010-07-15

    Aryl hydrocarbon receptor (AhR) activation by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) induces immune suppression. Dendritic cells (DCs) are key antigen presenting cells governing T cell activation and differentiation. However, the consequences of AhR activation in DCs are not fully defined. We hypothesized that AhR activation alters DC differentiation and generates dysfunctional DCs. To test this hypothesis, inflammatory bone marrow-derived DCs (BMDCs) from C57Bl/6 mice were generated in the presence of vehicle or TCDD. TCDD decreased CD11c expression but increased MHC class II, CD86 and CD25 expression on the BMDCs. The effects of TCDD were strictly AhR-dependent but not exclusively DRE-mediated. Similar effects were observed with two natural AhR ligands, 6-formylindolo[3,2-b]carbazole (FICZ) and 2-(1H-Indol-3-ylcarbonyl)-4-thiazolecarboxylic acid (ITE). TCDD increased LPS- and CpG-induced IL-6 and TNF-{alpha} production by BMDCs but decreased their NO production. TCDD decreased CpG-induced IL-12p70 production by BMDCs but did not affect their secretion of IL-10. TCDD downregulated LPS- and CpG-induced NF-kB p65 levels and induced a trend towards upregulation of RelB levels in the BMDCs. AhR activation by TCDD modulated BMDC uptake of both soluble and particulate antigens. Induction of indoleamine-2,3-dioxygenase (IDO) and TGF-{beta}3 has been implicated in the generation of regulatory T cells following AhR activation. TCDD increased IDO1, IDO2 and TGF-{beta}3 mRNA levels in BMDCs as compared to vehicle. Despite the induction of regulatory mediators, TCDD-treated BMDCs failed to suppress antigen-specific T cell activation. Thus, AhR activation can directly alter the differentiation and innate functions of inflammatory DCs without affecting their ability to successfully interact with T cells.

  5. Effects of scorched food leachates with or without activated charcoal pretreatment on AhR activation in cultured cells.

    PubMed

    Takahashi, Satoshi; Morita, Koji; Kinoshita, Makoto; Fujimori, Shin; Ishikawa, Toshio

    2015-12-01

    Aryl hydrocarbon receptor (AhR) is a transcription factor activated by xenobiotics, including dioxins and polycyclic aromatic hydrocarbons (PAHs). Although AhR is also activated by some dietary constituents, it has not been completely clarified in what circumstances AhR ligands are ingested in our daily life. Because PAHs are formed by the incomplete combustion of organic materials, we hypothesized that scorched foods might contain and leach out AhR ligands sufficient to stimulate AhR in vitro. To test this hypothesis, scorched foods (bread, cheese, etc.) were mixed vigorously with water, and the supernatants were retrieved as samples. The samples were added to HepG2 cells stably expressing an AhR-responsive reporter gene. Also, expression of CYP1A1, an endogenous AhR-responsive gene, was analyzed by RT-PCR in different cell lines treated with the samples. We further tested whether pretreatment of the samples with activated charcoal would alter their AhR-stimulating activity. All the supernatant samples tested induced AhR-dependent reporter gene activity and CYP1A1 mRNA expression. In some samples, these inductions were inhibited by pretreatment with activated charcoal. Our findings indicate that scorched food leachates stimulate AhR in cultured cells and that activated charcoal adsorbs the AhR-stimulating substances in some leachates. Thus, people who habitually eat scorched foods are exposed to AhR ligands on a regular basis. Further studies are needed to elucidate whether burnt foods actually exert biological effects on our health.

  6. Effects of scorched food leachates with or without activated charcoal pretreatment on AhR activation in cultured cells.

    PubMed

    Takahashi, Satoshi; Morita, Koji; Kinoshita, Makoto; Fujimori, Shin; Ishikawa, Toshio

    2015-12-01

    Aryl hydrocarbon receptor (AhR) is a transcription factor activated by xenobiotics, including dioxins and polycyclic aromatic hydrocarbons (PAHs). Although AhR is also activated by some dietary constituents, it has not been completely clarified in what circumstances AhR ligands are ingested in our daily life. Because PAHs are formed by the incomplete combustion of organic materials, we hypothesized that scorched foods might contain and leach out AhR ligands sufficient to stimulate AhR in vitro. To test this hypothesis, scorched foods (bread, cheese, etc.) were mixed vigorously with water, and the supernatants were retrieved as samples. The samples were added to HepG2 cells stably expressing an AhR-responsive reporter gene. Also, expression of CYP1A1, an endogenous AhR-responsive gene, was analyzed by RT-PCR in different cell lines treated with the samples. We further tested whether pretreatment of the samples with activated charcoal would alter their AhR-stimulating activity. All the supernatant samples tested induced AhR-dependent reporter gene activity and CYP1A1 mRNA expression. In some samples, these inductions were inhibited by pretreatment with activated charcoal. Our findings indicate that scorched food leachates stimulate AhR in cultured cells and that activated charcoal adsorbs the AhR-stimulating substances in some leachates. Thus, people who habitually eat scorched foods are exposed to AhR ligands on a regular basis. Further studies are needed to elucidate whether burnt foods actually exert biological effects on our health. PMID:26558458

  7. Cardiac Myocyte-Specific AHR Activation Phenocopies TCDD-Induced Toxicity in Zebrafish

    PubMed Central

    Lanham, Kevin A.; Plavicki, Jessica; Peterson, Richard E.; Heideman, Warren

    2014-01-01

    Exposure of zebrafish embryos to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) activates the zebrafish aryl hydrocarbon receptor 2 (AHR) to produce developmental and cardiovascular toxicity. AHR is found in the heart; however, AHR activation by TCDD is not confined to the heart and occurs throughout the organism. In order to understand the cause of cardiotoxicity, we constructed a constitutively active AHR (caAHR) based on the zebrafish AHR2 and expressed it specifically in cardiomyocytes. We show that AHR activation within the cardiomyocytes can account for the heart failure induced by TCDD. Expression of the caAHR within the heart produced cardiac malformations, loss of circulation, and pericardial edema. The heart-specific activation of AHR reproduced several other well-characterized endpoints of TCDD toxicity outside of the cardiovascular system, including defects in swim bladder and craniofacial development. This work identifies a single cellular site of TCDD action, the myocardial cell, that can account for the severe cardiovascular collapse observed following early life stage exposure to TCDD, and contributes to other forms of toxicity. PMID:25037585

  8. A constitutive active MAPK/ERK pathway due to BRAFV600E positively regulates AHR pathway in PTC

    PubMed Central

    Regazzo, Daniela; Bertazza, Loris; Galuppini, Francesca; Guzzardo, Vincenza; Jaffrain-Rea, Marie Lise; Vianello, Federica; Ciato, Denis; Ceccato, Filippo; Watutantrige-Fernando, Sara; Bisognin, Andrea; Bortoluzzi, Stefania; Pennelli, Gianmaria; Boscaro, Marco; Scaroni, Carla; Mian, Caterina

    2015-01-01

    The aryl hydrocarbon receptor (AHR) is a ligand-activated transcription factor mediating the toxicity and tumor-promoting properties of dioxin. AHR has been reported to be overexpressed and constitutively active in a variety of solid tumors, but few data are currently available concerning its role in thyroid cancer. In this study we quantitatively explored a series of 51 paired-normal and papillary thyroid carcinoma (PTC) tissues for AHR-related genes. We identified an increased AHR expression/activity in PTC, independently from its nuclear dimerization partner and repressor but strictly related to a constitutive active MAPK/ERK pathway. The AHR up-regulation followed by an increased expression of AHR target genes was confirmed by a meta-analysis of published microarray data, suggesting a ligand-independent active AHR pathway in PTC. In-vitro studies using a PTC-derived cell line (BCPAP) and HEK293 cells showed that BRAFV600E may directly modulate AHR localization, induce AHR expression and activity in an exogenous ligand-independent manner. The AHR pathway might represent a potential novel therapeutic target for PTC in the clinical practice. PMID:26392334

  9. AhR signaling activation disrupts migration and dendritic growth of olfactory interneurons in the developing mouse

    PubMed Central

    Kimura, Eiki; Ding, Yunjie; Tohyama, Chiharu

    2016-01-01

    Perinatal exposure to a low level of dioxin, a ubiquitous environmental pollutant, has been shown to induce abnormalities in learning and memory, emotion, and sociality in laboratory animals later in adulthood. However, how aryl hydrocarbon receptor (AhR) signaling activation disrupts the higher brain function remains unclear. Therefore, we studied the possible effects of excessive activation of AhR signaling on neurodevelopmental processes, such as cellular migration and neurite growth, in mice. To this end, we transfected a constitutively active-AhR plasmid into stem cells in the lateral ventricle by in vivo electroporation on postnatal day 1. Transfection was found to induce tangential migration delay and morphological abnormalities in neuronal precursors in the rostral migratory stream at 6 days post-electroporation (dpe) as well as disrupt radial migration in the olfactory bulb and apical and basal dendritic growth of the olfactory interneurons in the granule cell layer at 13 and 20 dpe. These results suggest that the retarded development of interneurons by the excessive AhR signaling may at least in part explain the dioxin-induced abnormal behavioral alterations previously reported in laboratory animals. PMID:27197834

  10. The immune phenotype of AhR null mouse mutants: not a simple mirror of xenobiotic receptor over-activation.

    PubMed

    Esser, Charlotte

    2009-02-15

    Intrinsic and induced cell differentiation and the cellular response to endogenous and exogenous signals are hallmarks of the immune system. Specific and common signalling cascades ensure a highly flexible and adapted response. Increasing evidence suggests that gene modulation by the aryl hydrocarbon receptor (AhR), a ligand-activated transcription factor, is an important part of these processes. For decades the AhR has been studied mainly for its toxic effects after artificial activation by man-made chemical pollutants such as dioxins. These studies gave important, albeit to some extent skewed, evidence for a mechanistic link between the AhR and the immune system. AhR null mutants and other mutants of the AhR signalling pathway have been generated and used to analyse the physiological function of the AhR, including for the developing and antigen-responding immune system. In this review I look at the natural immunological function(s) of the AhR.

  11. AhR activation underlies the CYP1A autoinduction by A-998679 in rats

    PubMed Central

    Liguori, Michael J.; Lee, Chih-Hung; Liu, Hong; Ciurlionis, Rita; Ditewig, Amy C.; Doktor, Stella; Andracki, Mark E.; Gagne, Gerard D.; Waring, Jeffrey F.; Marsh, Kennan C.; Gopalakrishnan, Murali; Blomme, Eric A. G.; Yang, Yi

    2012-01-01

    Xenobiotic-mediated induction of cytochrome P450 (CYP) drug metabolizing enzymes (DMEs) is frequently encountered in drug discovery and can influence disposition, pharmacokinetic, and toxicity profiles. The CYP1A subfamily of DMEs plays a central role in the biotransformation of several drugs and environmental chemicals. Autoinduction of drugs through CYP3A enzymes is a common mechanism for their enhanced clearance. However, autoinduction via CYP1A is encountered less frequently. In this report, an experimental compound, A-998679 [3-(5-pyridin-3-yl-1,2,4-oxadiazol-3-yl) benzonitrile], was shown to enhance its own clearance via induction of Cyp1a1 and Cyp1a2. Rats were dosed for 5 days with 30, 100, and 200 mg/kg/day A-998679. During the dosing period, the compound's plasma AUC decreased at 30 mg/kg (95%) and 100 mg/kg (80%). Gene expression analysis and immunohistochemistry of the livers showed a large increase in the mRNA and protein levels of Cyp1a, which was involved in the biotransformation of A-998679. Induction of CYP1A was confirmed in primary rat, human, and dog hepatocytes. The compound also weakly inhibited CYP1A2 in human liver microsomes. A-998679 activated the aryl hydrocarbon receptor (AhR) in a luciferase gene reporter assay in HepG2 cells, upregulated expression of genes associated with AhR activation in rat liver and enhanced nuclear migration of AhR in HepG2 cells. Collectively these results demonstrate that A-998679 is an AhR activator that induces Cyp1a1 and Cyp1a2 expression, resulting in an autoinduction phenomenon. The unique properties of A-998679, along with its novel structure distinct from classical polycyclic aromatic hydrocarbons (PAHs), may warrant its further evaluation as a tool compound for use in studies involving AhR biology and CYP1A-related mechanisms of drug metabolism and toxicity. PMID:23112805

  12. Assessment of energetic costs of AhR activation by β-naphthoflavone in rainbow trout (Oncorhynchus mykiss) hepatocytes using metabolic flux analysis

    SciTech Connect

    Nault, Rance; Abdul-Fattah, Hiba; Mironov, Gleb G.; Berezovski, Maxim V.; Moon, Thomas W.

    2013-08-15

    Exposure to environmental contaminants such as activators of the aryl hydrocarbon receptor (AhR) leads to the induction of defense and detoxification mechanisms. While these mechanisms allow organisms to metabolize and excrete at least some of these environmental contaminants, it has been proposed that these mechanisms lead to significant energetic challenges. This study tests the hypothesis that activation of the AhR by the model agonist β-naphthoflavone (βNF) results in increased energetic costs in rainbow trout (Oncorhynchus mykiss) hepatocytes. To address this hypothesis, we employed traditional biochemical approaches to examine energy allocation and metabolism including the adenylate energy charge (AEC), protein synthesis rates, Na{sup +}/K{sup +}-ATPase activity, and enzyme activities. Moreover, we have used for the first time in a fish cell preparation, metabolic flux analysis (MFA) an in silico approach for the estimation of intracellular metabolic fluxes. Exposure of trout hepatocytes to 1 μM βNF for 48 h did not alter hepatocyte AEC, protein synthesis, or Na{sup +}/K{sup +}-ATPase activity but did lead to sparing of glycogen reserves and changes in activities of alanine aminotransferase and citrate synthase suggesting altered metabolism. Conversely, MFA did not identify altered metabolic fluxes, although we do show that the dynamic metabolism of isolated trout hepatocytes poses a significant challenge for this type of approach which should be considered in future studies. - Highlights: • Energetic costs of AhR activation by βNF was examined in rainbow trout hepatocytes. • Metabolic flux analysis was performed on a fish cell preparation for the first time. • Exposure to βNF led to sparing of glycogen reserves and altered enzyme activities. • Adenylate energy charge was maintained despite temporal changes in metabolism.

  13. Effects of Developmental Activation of the AhR on CD4+ T-Cell Responses to Influenza Virus Infection in Adult Mice

    PubMed Central

    Boule, Lisbeth A.; Winans, Bethany

    2014-01-01

    Background: Epidemiological and animal studies indicate that maternal exposure to pollutants that bind the aryl hydrocarbon receptor (AhR) correlates with poorer ability to combat respiratory infection and lower antibody levels in the offspring. These observations point to an impact on CD4+ T cells. Yet, the consequence of developmental exposure to AhR ligands on the activation and differentiation of CD4+ T cells has not been directly examined. Objectives: Our goal was to determine whether maternal exposure to an AhR ligand directly alters CD4+ T cell differentiation and function later in life. Methods: C57BL/6 mice were exposed to a prototypical AhR ligand, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), in utero and via suckling. We then measured CD4+ T-cell activation and differentiation into distinct effector populations in adult offspring that were infected with influenza A virus (IAV). Reciprocal adoptive transfers were used to define whether modifications in CD4+ T-cell responses resulted from direct effects of developmental TCDD exposure on CD4+ T cells. Results: Developmental exposure skewed CD4+ T-cell responses to IAV infection. We observed fewer virus-specific, activated CD4+ T cells and a reduced frequency of conventional CD4+ effector-cell subsets. However, there was an increase in regulatory CD4+ T cells. Direct effects of AhR activation on CD4+ T cells resulted in impaired differentiation into conventional effector subsets; this defect was transferred to mice that had not been developmentally exposed to TCDD. Conclusions: Maternal exposure to TCDD resulted in durable changes in the responsive capacity and differentiation of CD4+ T cells in adult C57BL/6 mice. Citation: Boule LA, Winans B, Lawrence BP. 2014. Effects of developmental activation of the AhR on CD4+ T-cell responses to influenza virus infection in adult mice. Environ Health Perspect 122:1201–1208; http://dx.doi.org/10.1289/ehp.1408110 PMID:25051576

  14. Disruption of period gene expression alters the inductive effects of dioxin on the AhR signaling pathway in the mouse liver

    SciTech Connect

    Qu Xiaoyu; Metz, Richard P.; Porter, Weston W.; Cassone, Vincent M.; Earnest, David J.

    2009-02-01

    The aryl hydrocarbon receptor (AhR) and AhR nuclear translocator (ARNT) are transcription factors that express Per-Arnt-Sim (PAS) DNA-binding motifs and mediate the metabolism of drugs and environmental toxins in the liver. Because these transcription factors interact with other PAS genes in molecular feedback loops forming the mammalian circadian clockworks, we determined whether targeted disruption or siRNA inhibition of Per1 and Per2 expression alters toxin-mediated regulation of the AhR signaling pathway in the mouse liver and Hepa1c1c7 hepatoma cells in vitro. Treatment with the prototypical Ahr ligand, 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD), had inductive effects on the primary targets of AhR signaling, Cyp1A1 and Cyp1B1, in the liver of all animals, but genotype-based differences were evident such that the toxin-mediated induction of Cyp1A1 expression was significantly greater (2-fold) in mice with targeted disruption of Per1 (Per1{sup ldc} and Per1{sup ldc}/Per2{sup ldc}). In vitro experiments yielded similar results demonstrating that siRNA inhibition of Per1 significantly increases the TCDD-induced expression of Cyp1A1 and Cyp1B1 in Hepa1c1c7 cells. Per2 inhibition in siRNA-infected Hepa1c1c7 cells had the opposite effect and significantly decreased both the induction of these p450 genes as well as AhR and Arnt expression in response to TCDD treatment. These findings suggest that Per1 may play a distinctive role in modulating AhR-regulated responses to TCDD in the liver.

  15. Arylhydrocarbon receptor (AhR) activation in airway epithelial cells induces MUC5AC via reactive oxygen species (ROS) production.

    PubMed

    Chiba, Takahito; Uchi, Hiroshi; Tsuji, Gaku; Gondo, Hisaki; Moroi, Yoichi; Furue, Masutaka

    2011-02-01

    The dioxins and dioxin-like compounds in cigarette smoke regulate various immunological responses via the arylhydrocarbon receptor (AhR). These environmental toxicants are known to cause bronchitis, asthma, chronic obstructive pulmonary disease (COPD), and lung cancer. Recent studies have demonstrated that AhR activation upregulates the expression of mucin 5AC, oligomeric mucus/gel-forming (MUC5AC) in the airway epithelial cell line. However, the mechanism for the production of mucin has not been clarified. In this study, we investigated the role and pathway of AhR in airway epithelial cells by using selective agonists and antagonists. After stimulation with or without benzopyrene (B[a]P), an AhR agonist, MUC5AC expression was measured by real-time RT-PCR. The mechanism of AhR-induced MUC5AC expression in airway epithelial cells was studied in terms of the production of cytokine and reactive oxygen species (ROS). Treatment with B[a]P increased ROS generation in NCI-H₂₉₂ cells. Furthermore, B[a]P-induced MUC5AC upregulation and mucin production were inhibited by AhR siRNA or the use of an antioxidative agent. These results suggest that the AhR-induced increase of mucin production is partially mediated by ROS generation. An antioxidant therapy approach may help to cure AhR-induced mucus hypersecretory diseases. PMID:20709182

  16. Benzo[ghi]perylene activates the AHR pathway to exert biological effects on the NL-20 human bronchial cell line.

    PubMed

    Zaragoza-Ojeda, Montserrat; Eguía-Aguilar, Pilar; Perezpeña-Díazconti, Mario; Arenas-Huertero, Francisco

    2016-08-10

    Polycyclic aromatic hydrocarbons (PAH) are produced by incomplete combustion of organic material. In the Mexico City atmosphere, the most abundant PAH is benzo[ghi]perylene (BghiP), a gasoline combustion marker. At present, there are no reports of the effects of BghiP on human bronchial cells, so the aim of the study was to evaluate the effects in vitro of BghiP on the NL-20 cell line. Results showed that BghiP induced the formation of small vesicles throughout the cytoplasm, with absence of nuclear fragmentation. At 48h exposition, damage in cell membrane increased significantly at 1.24μg/mL of BghiP (p<0.05). Immunocytochemistry revealed that BghiP provokes nuclear translocation of AhR receptor, which indicates that this compound can induce transcription of genes via receptor binding (AhR pathway activation). BghiP induced a two-fold increase (p<0.05) in the expression of AhR and CYP4B1 (a lung-specific pathway effector). In the presence of the receptor antagonist CH-223191, the loss of viability, the nuclear translocation and the overexpression of genes decreased, though this did not prevent the formation of vesicles. BghiP induced oxidative stress and in presence of the receptor antagonist this increased significantly. In conclusion, BghiP can activate the overexpression of AhR and CYP4B1, and the effects are abated by the AhR receptor antagonist. This is the first report to prove that BghiP utilizes the AhR pathway to exert its toxic effects on the NL-20 human bronchial cell line . PMID:27234499

  17. Characterization of AhR agonists reveals antagonistic activity in European herring gull (Larus argentatus) eggs.

    PubMed

    Muusse, Martine; Christensen, Guttorm; Gomes, Tânia; Kočan, Anton; Langford, Katherine; Tollefsen, Knut Erik; Vaňková, Lenka; Thomas, Kevin V

    2015-05-01

    European herring gull (Larus argentatus) eggs from two Norwegian islands, Musvær in the south east and Reiaren in Northern Norway, were screened for dioxins, furans, and dioxin-like and selected non-dioxin-like polychlorinated biphenyls (PCBs), and subjected to non-target analysis to try to identify the aryl hydrocarbon receptor (AhR) agonists, responsible for elevated levels measured using the dioxin responsive chemically activated luciferase expression (DR-CALUX) assay. Eggs from Musvær contained chemically calculated toxic equivalent (WHO TEQ) levels of between 109 and 483 pg TEQ/g lw, and between 82 and 337 pg TEQ/g lw was determined in eggs from Reiaren. In particular PCB126 contributed highly to the total TEQ (69-82%). In 19 of the 23 samples the calculated WHO TEQ was higher than the TEQCALUX. Using CALUX specific relative effect potencies (REPs), the levels were lower at between 77 and 292 pg/g lw in eggs from Musvær and between 55 and 223 pg/g lw in eggs from Reiaren, which was higher than the TEQCALUX in 16 of the 23 samples. However, the means of the REP values and the TEQCALUX were not significantly different. This suggests the presence of compounds that can elicit antagonist effects, with a low binding affinity to the AhR. Non-target analysis identified the presence of hexachlorobenzene (HCB) (quantified at 9.6-185 pg/g lw) but neither this compound nor high concentrations of PCB126 and non-dioxin-like PCBs could explain the differences between the calculated TEQ or REP values and the TEQCALUX. Even though, for most AhR agonists, the sensitivity of herring gulls is not known, the reported levels can be considered to represent a risk for biological effects in the developing embryo, compared to LC50 values in chicken embryos. For human consumers of herring gull eggs, these eggs contain TEQ levels up to four times higher than the maximum tolerable weekly intake.

  18. Exposure to Diesel Exhaust Particle Extracts (DEPe) Impairs Some Polarization Markers and Functions of Human Macrophages through Activation of AhR and Nrf2

    PubMed Central

    Jaguin, Marie; Fardel, Olivier; Lecureur, Valérie

    2015-01-01

    Macrophages (MΦ), well-known to play an important role in immune response, also respond to environmental toxic chemicals such as diesel exhaust particles (DEP). Potential effects of DEPs towards MΦ polarization, a key hall-mark of MΦ physiology, remain however poorly documented. This study was therefore designed to evaluate the effects of a reference DEP extract (DEPe) on human MΦ polarization. Human blood monocytes-derived MΦ were incubated with IFNγ+LPS or IL-4 to obtain M1 and M2 subtypes, respectively; a 24 h exposure of polarizing MΦ to 10 μg/ml DEPe was found to impair expression of some macrophagic M1 and M2 markers, without however overall inhibition of M1 and M2 polarization processes. Notably, DEPe treatment increased the secretion of the M1 marker IL-8 and the M2 marker IL-10 in both MΦ subtypes, whereas it reduced lipopolysaccharide-induced IL-6 and IL-12p40 secretion in M1 MΦ. In M2 MΦ, DEPe exposure led to a reduction of CD200R expression and of CCL17, CCL18 and CCL22 secretion, associated with a lower chemotaxis of CCR4-positive cells. DEPe activated the Nrf2 and AhR pathways and induced expression of their reference target genes such as Hmox-1 and cytochrome P-4501B1 in M1 and M2 MΦ. Nrf2 or AhR silencing through RNA interference prevented DEPe-related down-regulation of IL-6. AhR silencing also inhibited the down-secretion of IL-12p40 and CCL18 in M1- and M2-DEPe-exposed MΦ, respectively. DEPs are therefore likely to alter expression of some M1 and M2 markers in an AhR- and Nrf2-dependent manner; such regulations may contribute to deleterious immune effects of atmospheric DEP. PMID:25710172

  19. The Effects of Chronic Lifelong Activation of the AHR Pathway by Industrial Chemical Pollutants on Female Human Reproduction

    PubMed Central

    Vacca, Margherita; Nardelli, Claudia; Castegna, Alessandra; Arnesano, Fabio; Carella, Nicola; Depalo, Raffaella

    2016-01-01

    Environmental chemicals, such as heavy metals, affect female reproductive function. A biological sensor of the signals of many toxic chemical compounds seems to be the aryl hydrocarbon receptor (AHR). Previous studies demonstrated the environmental of heavy metals in Taranto city (Italy), an area that has been influenced by anthropogenic factors such as industrial activities and waste treatments since 1986. However, the impact of these elements on female fertility in this geographic area has never been analyzed. Thus, in the present study, we evaluated the AHR pathway, sex steroid receptor pattern and apoptotic process in granulosa cells (GCs) retrieved from 30 women, born and living in Taranto, and 30 women who are living in non-contaminated areas (control group), who were undergoing in vitro fertilization (IVF) protocol. In follicular fluids (FFs) of both groups the toxic and essential heavy metals, such as chromiun (Cr), Manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), cadmium (Cd) and lead (Pb), were also analyzed. Higher levels of Cr, Fe, Zn and Pb were found in the FFs of the women from Taranto as compared to the control group, as were the levels of AHR and AHR-dependent cytochrome P450 1A1 and 1B1; while CYP19A1 expression was decreased. The anti-apoptotic process found in the GCs of women fromTaranto was associated with the highest levels of progesterone receptor membrane component 1 (PGRMC1), a novel progesterone receptor, the expression of which is subjected to AHR activated by its highest affinity ligands (e.g., dioxins) or indirectly by other environmental pollutants, such as heavy metals. In conclusion, decreased production of estradiol and decreased number of retrieved mature oocytes found in women from Taranto could be due to chronic exposure to heavy metals, in particular to Cr and Pb. PMID:27008165

  20. TCDD promoted EMT of hFPECs via AhR, which involved the activation of EGFR/ERK signaling.

    PubMed

    Gao, Zhan; Bu, Yongjun; Liu, Xiaozhuan; Wang, Xugang; Zhang, Guofu; Wang, Erhui; Ding, Shibin; Liu, Yongfeng; Shi, Ruling; Li, Qiaoyun; Fu, Jianhong; Yu, Zengli

    2016-05-01

    One critical step of second palatal fusion is the newly formed medial epithelia seam (MES) disintegration, which involves apoptosis, epithelial to mesenchymal transition (EMT), and cell migration. Although the environmental toxicant 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) produces cleft palate at high rates, little is known about the effects of TCDD exposure on the fate of palatal epithelial cells. By using primary epithelial cells isolated from human fetal palatal shelves (hFPECs), we show that TCDD increased cell proliferation and EMT, as demonstrated by increased the epithelial markers (E-cadherin and cytokeratin14) and enhanced the mesenchymal markers (vimentin and fibronectin), but had no effect on cell migration and apoptosis. TCDD exposure led to a dose-dependent increase in Slug protein expression. Coimmunoprecipitation revealed that TCDD promoted AhR to form a protein complex with Slug. ChIP assay confirmed that TCDD exposure recruited AhR to the xenobiotic responsive element of Slug promoter. Knockdown of AhR by siRNA remarkably weakened TCDD-induced binding of AhR to the XRE promoter of slug, thereby suppressed TCDD-induced vimentin. Further experiment showed that TCDD stimulated EGFR phosphorylation did not influence the TGFβ3/Smad signaling; whereas TCDD increased phosphorylation of ERK1/2 and p38 with no effect on activation of JNK. By using varieties of inhibitors, we confirmed that TCDD promoted proliferation and EMT of hFPECs via activation of EGFR/ERK pathway. These data make a novel contribution to the molecular mechanism of cleft palate by TCDD. PMID:26971374

  1. Dioxin-Dependent and Dioxin-Independent Gene Batteries: Comparison of Liver and Kidney in AHR-Null Mice

    PubMed Central

    Boutros, Paul C.; Bielefeld, Kirsten A.; Pohjanvirta, Raimo; Harper, Patricia A.

    2009-01-01

    The aryl hydrocarbon receptor (AHR) is a widely expressed ligand-dependent transcription factor that mediates cellular responses to dioxins and other planar aromatic hydrocarbons. Ahr-null mice are refractory to the toxic effects of dioxin exposure. Although some mechanistic aspects of AHR activity are well understood, the tissue specificity of AHR effects remains unclear, both during development and following administration of exogenous ligands. To address the latter issue, we defined and compared transcriptional responses to dioxin exposure in the liver and kidney of wild-type and Ahr-null adult C57BL/6J mice treated with either 2,3,7,8-tetrachlorodibenzo-p-dioxin or corn-oil vehicle. In both tissues, essentially all effects of dioxin on hepatic mRNA levels were mediated by the AHR. Although 297 genes were altered by dioxin exposure in the liver, only 17 were changed in the kidney, including a number of well-established AHR target genes. Ahr genotype had a large effect in both tissues, profoundly remodeling both the renal and hepatic transcriptomes. Surprisingly, a large number of genes were affected by Ahr genotype in both tissues, suggesting the presence of a basal AHR gene battery. Alterations of the renal transcriptome in Ahr-null animals were associated with perturbation of specific functional pathways and enrichment of specific DNA motifs. Our results demonstrate the importance of intertissue comparisons, highlight the basal role of the AHR in liver and kidney, and support a role in development or normal physiology. PMID:19759094

  2. ITE and TCDD differentially regulate the vascular remodeling of rat placenta via the activation of AhR.

    PubMed

    Wu, Yanming; Chen, Xiao; Zhou, Qian; He, Qizhi; Kang, Jiuhong; Zheng, Jing; Wang, Kai; Duan, Tao

    2014-01-01

    Vascular remodeling in the placenta is essential for normal fetal development. The previous studies have demonstrated that in utero exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD, an environmental toxicant) induces the intrauterine fetal death in many species via the activation of aryl hydrocarbon receptor (AhR). In the current study, we compared the effects of 2-(1'H-indole-3'-carbonyl)-thiazole-4-carboxylic acid methyl ester (ITE) and TCDD on the vascular remodeling of rat placentas. Pregnant rats on gestational day (GD) 15 were randomly assigned into 5 groups, and were exposed to a single dose of 1.6 and 8.0 mg/kg body weight (bw) ITE, 1.6 and 8.0 µg/kg bw TCDD, or an equivalent volume of the vehicle, respectively. The dams were sacrificed on GD20 and the placental tissues were gathered. The intrauterine fetal death was observed only in 8.0 µg/kg bw TCDD-exposed group and no significant difference was seen in either the placental weight or the fetal weight among all these groups. The immunohistochemical and histological analyses revealed that as compared with the vehicle-control, TCDD, but not ITE, suppressed the placental vascular remodeling, including reduced the ratio of the placental labyrinth zone to the basal zone thickness (at least 0.71 fold of control), inhibited the maternal sinusoids dilation and thickened the trophoblastic septa. However, no marked difference was observed in the density of fetal capillaries in the labyrinth zone among these groups, although significant differences were detected in the expression of angiogenic growth factors between ITE and TCDD-exposed groups, especially Angiopoietin-2 (Ang-2), Endoglin, Interferon-γ (IFN-γ) and placenta growth factor (PIGF). These results suggest ITE and TCDD differentially regulate the vascular remodeling of rat placentas, as well as the expression of angiogenic factors and their receptors, which in turn may alter the blood flow in the late gestation and partially resulted in

  3. In vitro and in silico evaluation of transactivation potencies of avian AHR1 and AHR2 by endogenous ligands: Implications for the physiological role of avian AHR2.

    PubMed

    Kim, In-Sung; Hwang, Ji-Hee; Hirano, Masashi; Iwata, Hisato; Kim, Eun-Young

    2016-09-01

    Aryl hydrocarbon receptor (AHR) is well conserved from invertebrates to vertebrates, and it mediates the toxic effects of exogenous ligands, including dioxins. Recent studies reported that AHRs activated by endogenous ligands play critical roles in mammalian physiological homeostasis. Avian species possess at least two AHR isoforms (AHR1 and AHR2), which exhibit species- and isoform-specific transactivation potencies to exogenous ligands, whereas mammals possess a single AHR. To delineate the profiles and roles of endogenous ligands for avian AHR isoforms, we investigated in vitro transactivation potencies of avian AHRs (AHR1 and AHR2 from the jungle crow, Corvus macrorhynchos; common cormorant, Phalacrocorax carbo; and black-footed albatross, Phoebastria nigripes) treated with the endogenous tryptophan metabolites 6-formylindolo [3,2-b] carbazole (FICZ), l-kynurenine (l-Kyn), kynurenic acid (KYNA), and indoxyl sulfate (IS). Furthermore, we analyzed the binding mode of these ligands to each avian AHR isoform by in silico docking simulations. The EC50 of FICZ (0.009-0.032nM) was similar regardless of the species or isoform of AHR. The estimated in silico binding mode of FICZ to AHRs was well conserved in both isoforms. The transactivation potencies of avian AHRs to other tryptophan metabolites were 10(5)-10(7) fold lower than those for FICZ, and EC50 values varied in a species- and isoform-specific manner. This was consistent with poor conservation of the binding mode of l-Kyn, KYNA, and IS predicted in in silico docking simulations. Our results suggest that in avian species, FICZ is the most potent endogenous AHR ligand, and that AHR1 and AHR2 are physiologically functional. PMID:27060260

  4. Baicalein induces G1 arrest in oral cancer cells by enhancing the degradation of cyclin D1 and activating AhR to decrease Rb phosphorylation

    SciTech Connect

    Cheng, Ya-Hsin; Li, Lih-Ann; Lin, Pinpin; Cheng, Li-Chuan; Hung, Chein-Hui; Chang, Nai Wen; Lin, Chingju

    2012-09-15

    Baicalein is a flavonoid, known to have anti-inflammatory and anti-cancer effects. As an aryl hydrocarbon receptor (AhR) ligand, baicalein at high concentrations blocks AhR-mediated dioxin toxicity. Because AhR had been reported to play a role in regulating the cell cycle, we suspected that the anti-cancer effect of baicalein is associated with AhR. This study investigated the molecular mechanism involved in the anti-cancer effect of baicalein in oral cancer cells HSC-3, including whether such effect would be AhR-mediated. Results revealed that baicalein inhibited cell proliferation and increased AhR activity in a dose-dependent manner. Cell cycle was arrested at the G1 phase and the expression of CDK4, cyclin D1, and phosphorylated retinoblastoma (pRb) was decreased. When the AhR was suppressed by siRNA, the reduction of pRb was partially reversed, accompanied by a decrease of cell population at G1 phase and an increase at S phase, while the reduction of cyclin D1 and CDK4 did not change. This finding suggests that the baicalein activation of AhR is indeed associated with the reduction of pRb, but is independent of the reduction of cyclin D1 and CDK4. When cells were pre-treated with LiCl, the inhibitor of GSK-3β, the decrease of cyclin D1 was blocked and the reduction of pRb was recovered. The data indicates that in HSC-3 the reduction of pRb is both mediated by baicalein through activation of AhR and facilitation of cyclin D1 degradation, which causes cell cycle arrest at the G1 phase, and results in the inhibition of cell proliferation. -- Highlights: ► Baicalein causes the G1 phase arrest by decreasing Rb phosphorylation. ► Baicalein modulates AhR-mediated cell proliferation. ► Both AhR activation and cyclin D1 degradation results in hypophosphorylation of Rb. ► Baicalein facilitates cyclin D1 degradation by signalling the GSK-3β pathway.

  5. Measured and predicted affinities of binding and relative potencies to activate the AhR of PAHs and their alkylated analogues.

    PubMed

    Lee, Sangwoo; Shin, Woong-Hee; Hong, Seongjin; Kang, Habyeong; Jung, Dawoon; Yim, Un Hyuk; Shim, Won Joon; Khim, Jong Seong; Seok, Chaok; Giesy, John P; Choi, Kyungho

    2015-11-01

    Polycyclic aromatic hydrocarbons (PAHs) and their alkylated forms are important components of crude oil. Both groups of PAHs have been reported to cause dioxin-like responses, mediated by aryl hydrocarbon receptor (AhR). Thus, characterization of binding affinity to the AhR of unsubstituted or alkylated PAHs is important to understand the toxicological consequences of oil contamination on ecosystems. We investigated the potencies of major PAHs of crude oil, e.g., chrysene, phenanthrene and dibenzothiophene, and their alkylated forms (n=17) to upregulate expression of AhR-mediated processes by use of the H4IIE-luc transactivation bioassay. In addition, molecular descriptors of different AhR activation potencies among PAHs were investigated by use of computational molecular docking models. Based on responses of the H4IIE-luc in vitro assay, it was shown that potencies of PAHs were determined by alkylation in addition to the number and conformation of rings. Potencies of AhR-mediated processes were generally greater when a chrysene group was substituted, especially in 1-methyl-chrysene. Significant negative correlations were observed between the in vitro dioxin-like potency measured in H4IIE-luc cells and the binding distance estimated from the in silico modeling. The difference in relative potency for AhR activation observed among PAHs and their alkylated forms could be explained by differences among binding distances in the ligand binding domain of the AhR caused by alkylation. The docking model developed in the present study may have utility in predicting risks of environmental contaminants of which toxicities are mediated by AhR binding.

  6. Mixed-ligand copper(II) complexes activate aryl hydrocarbon receptor AhR and induce CYP1A genes expression in human hepatocytes and human cell lines.

    PubMed

    Kubešová, Kateřina; Dořičáková, Aneta; Trávníček, Zdeněk; Dvořák, Zdeněk

    2016-07-25

    The effects of four copper(II) mixed-ligand complexes [Cu(qui1)(L)]NO3·H2O (1-3) and [Cu(qui2)(phen)]NO3 (4), where qui1=2-phenyl-3-hydroxy-4(1H)-quinolinone, Hqui2=2-(4-amino-3,5-dichlorophenyl)-N-propyl-3-hydroxy-4(1H)-quinolinone-7-carboxamide, L=1,10-phenanthroline (phen) (1), 5-methyl-1,10-phenanthroline (mphen) (2), bathophenanthroline (bphen) (3), on transcriptional activities of steroid receptors, nuclear receptors and xenoreceptors have been studied. The complexes (1-4) did not influence basal or ligand-inducible activities of glucocorticoid receptor, androgen receptor, thyroid receptor, pregnane X receptor and vitamin D receptor, as revealed by gene reporter assays. The complexes 1 and 2 dose-dependently induced luciferase activity in stable gene reporter AZ-AhR cell line, and this induction was reverted by resveratrol, indicating involvement of aryl hydrocarbon receptor (AhR) in the process. The complexes 1, 2 and 3 induced CYP1A1 mRNA in LS180 cells and CYP1A1/CYP1A2 in human hepatocytes through AhR. Electrophoretic mobility shift assay EMSA showed that the complexes 1 and 2 transformed AhR in its DNA-binding form. Collectively, we demonstrate that the complexes 1 and 2 activate AhR and induce AhR-dependent genes in human hepatocytes and cancer cell lines. In conclusion, the data presented here might be of toxicological importance, regarding the multiple roles of AhR in human physiology and pathophysiology. PMID:27180721

  7. Aryl hydrocarbon receptor (AhR) inducers and estrogen receptor (ER) activities in surface sediments of Three Gorges Reservoir, China evaluated with in vitro cell bioassays.

    PubMed

    Wang, Jingxian; Bovee, Toine F H; Bi, Yonghong; Bernhöft, Silke; Schramm, Karl-Werner

    2014-02-01

    Two types of biological tests were employed for monitoring the toxicological profile of sediment cores in the Three Gorges Reservoir (TGR), China. In the present study, sediments collected in June 2010 from TGR were analyzed for estrogen receptor (ER)- and aryl hydrocarbon receptor (AhR)-mediated activities. The estrogenic activity was assessed using a rapid yeast estrogen bioassay, based on the expression of a green fluorescent reporter protein. Weak anti-estrogenic activity was detected in sediments from an area close to the dam of the reservoir, and weak estrogenic activities ranging from 0.3 to 1 ng 17β-estradiol (E2) equivalents (EQ) g(-1) dry weight sediment (dw) were detected in sediments from the Wanzhou to Guojiaba areas. In the upstream areas Wanzhou and Wushan, sediments demonstrated additive effects in co-administration of 1 nM E2 in the yeast test system, while sediments from the downstream Badong and Guojiaba areas showed estrogenic activities which seemed to be more than additive (synergistic activity). There was an increasing tendency in estrogenic activity from upstream of TGR to downstream, while this tendency terminated and converted into anti-estrogenic activity in the area close to the dam. The AhR activity was detected employing rat hepatoma cell line (H4IIE). EROD activities were found homogenously distributed in sediments in TGR ranging from 200 to 311 pg 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) EQ g(-1) dw for total AhR agonists and from 45 to 76 pg TCDD EQ g(-1) dw for more persistent AhR agonists. The known AhR agonists polycyclic aromatic hydrocarbon, polychlorinated biphenyl, and PCDD/F only explained up to 8 % of the more persistent AhR agonist activity in the samples, which suggests that unidentified AhR-active compounds represented a great proportion of the TCDD EQ in sediments from TGR. These findings of estrogenic potential and dioxin-like activity in TGR sediments provide possible weight-of-evidence of potential

  8. Aryl hydrocarbon receptor (AhR) inducers and estrogen receptor (ER) activities in surface sediments of Three Gorges Reservoir, China evaluated with in vitro cell bioassays.

    PubMed

    Wang, Jingxian; Bovee, Toine F H; Bi, Yonghong; Bernhöft, Silke; Schramm, Karl-Werner

    2014-02-01

    Two types of biological tests were employed for monitoring the toxicological profile of sediment cores in the Three Gorges Reservoir (TGR), China. In the present study, sediments collected in June 2010 from TGR were analyzed for estrogen receptor (ER)- and aryl hydrocarbon receptor (AhR)-mediated activities. The estrogenic activity was assessed using a rapid yeast estrogen bioassay, based on the expression of a green fluorescent reporter protein. Weak anti-estrogenic activity was detected in sediments from an area close to the dam of the reservoir, and weak estrogenic activities ranging from 0.3 to 1 ng 17β-estradiol (E2) equivalents (EQ) g(-1) dry weight sediment (dw) were detected in sediments from the Wanzhou to Guojiaba areas. In the upstream areas Wanzhou and Wushan, sediments demonstrated additive effects in co-administration of 1 nM E2 in the yeast test system, while sediments from the downstream Badong and Guojiaba areas showed estrogenic activities which seemed to be more than additive (synergistic activity). There was an increasing tendency in estrogenic activity from upstream of TGR to downstream, while this tendency terminated and converted into anti-estrogenic activity in the area close to the dam. The AhR activity was detected employing rat hepatoma cell line (H4IIE). EROD activities were found homogenously distributed in sediments in TGR ranging from 200 to 311 pg 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) EQ g(-1) dw for total AhR agonists and from 45 to 76 pg TCDD EQ g(-1) dw for more persistent AhR agonists. The known AhR agonists polycyclic aromatic hydrocarbon, polychlorinated biphenyl, and PCDD/F only explained up to 8 % of the more persistent AhR agonist activity in the samples, which suggests that unidentified AhR-active compounds represented a great proportion of the TCDD EQ in sediments from TGR. These findings of estrogenic potential and dioxin-like activity in TGR sediments provide possible weight-of-evidence of potential

  9. In Utero and Lactational Exposure to PCBs in Mice: Adult Offspring Show Altered Learning and Memory Depending on Cyp1a2 and Ahr Genotypes

    PubMed Central

    Curran, Christine P.; Genter, Mary Beth; Patel, Krishna V.; Schaefer, Tori L.; Skelton, Matthew R.; Williams, Michael T.; Vorhees, Charles V.

    2011-01-01

    Background: Both coplanar and noncoplanar polychlorinated biphenyls (PCBs) exhibit neurotoxic effects in animal studies, but individual congeners do not always produce the same effects as PCB mixtures. Humans genetically have > 60-fold differences in hepatic cytochrome P450 1A2 (CYP1A2)-uninduced basal levels and > 12-fold variability in aryl hydrocarbon receptor (AHR)affinity; because CYP1A2 is known to sequester coplanar PCBs and because AHR ligands include coplanar PCBs, both genotypes can affect PCB response. Objectives: We aimed to develop a mouse paradigm with extremes in Cyp1a2 and Ahr genotypes to explore genetic susceptibility to PCB-induced developmental neurotoxicity using an environmentally relevant mixture of PCBs. Methods: We developed a mixture of eight PCBs to simulate human exposures based on their reported concentrations in human tissue, breast milk, and food supply. We previously characterized specific differences in PCB congener pharmacokinetics and toxicity, comparing high-affinity–AHR Cyp1a2 wild-type [Ahrb1_Cyp1a2(+/+)], poor-affinity–AHR Cyp1a2 wild-type [Ahrd_Cyp1a2(+/+)], and high-affinity–AHR Cyp1a2 knockout [Ahrb1_Cyp1a2(–/–)] mouse lines [Curran CP, Vorhees CV, Williams MT, Genter MB, Miller ML, Nebert DW. 2011. In utero and lactational exposure to a complex mixture of polychlorinated biphenyls: toxicity in pups dependent on the Cyp1a2 and Ahr genotypes. Toxicol Sci 119:189–208]. Dams received a mixture of three coplanar and five noncoplanar PCBs on gestational day 10.5 and postnatal day (PND) 5. In the present study we conducted behavioral phenotyping of exposed offspring at PND60, examining multiple measures of learning, memory, and other behaviors. Results: We observed the most significant deficits in response to PCB treatment in Ahrb1_Cyp1a2(–/–) mice, including impaired novel object recognition and increased failure rate in the Morris water maze. However, all PCB-treated genotypes showed significant differences on

  10. AHR-11797: a novel benzodiazepine antagonist

    SciTech Connect

    Johnson, D.N.; Kilpatrick, B.F.; Hannaman, P.K.

    1986-03-01

    AHR-11797(5,6-dihydro-6-methyl-1-phenyl-/sup 3/H-pyrrolo(3,2,1-ij)quinazolin-3-one) displaced /sup 3/H-flunitrazepam (IC/sub 50/ = 82 nM) and /sup 3/H-Ro 15-1877 (IC/sub 50/ = 104 nM) from rat brain synaptosomes. AHR-11797 did not protect mice from seizures induced by maximal electroshock or subcutaneous Metrazol (scMET), nor did it induce seizures in doses up to the lethal dose. However, at 31.6 mg/kg, IP, it significantly increased the anticonvulsant ED/sub 50/ of chlordiazepoxide (CDPX) from 1.9 to 31.6 mg/kg, IP. With 56.7 mg/kg, IP, of AHR-11797, CDPX was inactive in doses up to 100 mg/kg, IP. AHR-11797 did not significantly increase punished responding in the Geller and Seifter conflict procedure, but it did attenuate the effects of diazepam. Although the compound is without anticonvulsant or anxiolytic activity, it did have muscle relaxant properties. AHR-11797 blocked morphine-induced Straub tail in mice (ED/sub 50/ = 31 mg/kg, IP) and it selectively suppressed the polysnaptic linguomandibular reflex in barbiturate-anesthetized cats. The apparent muscle relaxant activity of AHR-11797 suggests that different receptor sites are involved for muscle relaxant vs. anxiolytic/anticonvulsant activities of the benzodiazepines.

  11. AhR signalling and dioxin toxicity.

    PubMed

    Sorg, Olivier

    2014-10-15

    Dioxins are a family of molecules associated to several industrial accidents such as Ludwigshafen in 1953 or Seveso in 1976, to the Agent Orange used during the war of Vietnam, and more recently to the poisoning of the former president of Ukraine, Victor Yushchenko. These persistent organic pollutants are by-products of industrial activity and bind to an intracellular receptor, AhR, with a high potency. In humans, exposure to dioxins, in particular 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) induces a cutaneous syndrome known as chloracne, consisting in the development of many small skin lesions (hamartoma), lasting for 2-5 years. Although TCDD has been classified by the WHO as a human carcinogen, its carcinogenic potential to humans is not clearly demonstrated. It was first believed that AhR activation accounted for most, if not all, biological properties of dioxins. However, certain AhR agonists found in vegetables do not induce chloracne, and other chemicals, in particular certain therapeutic agents, may induce a chloracne-like syndrome without activating AhR. It is time to rethink the mechanism of dioxin toxicity and analyse in more details the biological events following exposure to these compounds and other AhR agonists, some of which have a very different chemical structure than TCDD. In particular various food-containing AhR agonists are non-toxic and may on the contrary have beneficial properties to human health. PMID:24239782

  12. Dioxin induces Ahr-dependent robust DNA demethylation of the Cyp1a1 promoter via Tdg in the mouse liver

    PubMed Central

    Amenya, Hesbon Z.; Tohyama, Chiharu; Ohsako, Seiichiroh

    2016-01-01

    The aryl hydrocarbon receptor (Ahr) is a highly conserved nuclear receptor that plays an important role in the manifestation of toxicity induced by polycyclic aromatic hydrocarbons. As a xenobiotic sensor, Ahr is involved in chemical biotransformation through activation of drug metabolizing enzymes. The activated Ahr cooperates with coactivator complexes to induce epigenetic modifications at target genes. Thus, it is conceivable that 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), a potent Ahr ligand, may elicit robust epigenetic changes in vivo at the Ahr target gene cytochrome P450 1a1 (Cyp1a1). A single dose of TCDD administered to adult mice induced Ahr-dependent CpG hypomethylation, changes in histone modifications, and thymine DNA glycosylase (Tdg) recruitment at the Cyp1a1 promoter in the liver within 24 hrs. These epigenetic changes persisted until 40 days post-TCDD treatment and there was Cyp1a1 mRNA hyperinduction upon repeat administration of TCDD at this time-point. Our demethylation assay using siRNA knockdown and an in vitro methylated plasmid showed that Ahr, Tdg, and the ten-eleven translocation methyldioxygenases Tet2 and Tet3 are required for the TCDD-induced DNA demethylation. These results provide novel evidence of Ahr-driven active DNA demethylation and epigenetic memory. The epigenetic alterations influence response to subsequent chemical exposure and imply an adaptive mechanism to xenobiotic stress. PMID:27713569

  13. Dioxin induces Ahr-dependent robust DNA demethylation of the Cyp1a1 promoter via Tdg in the mouse liver

    NASA Astrophysics Data System (ADS)

    Amenya, Hesbon Z.; Tohyama, Chiharu; Ohsako, Seiichiroh

    2016-10-01

    The aryl hydrocarbon receptor (Ahr) is a highly conserved nuclear receptor that plays an important role in the manifestation of toxicity induced by polycyclic aromatic hydrocarbons. As a xenobiotic sensor, Ahr is involved in chemical biotransformation through activation of drug metabolizing enzymes. The activated Ahr cooperates with coactivator complexes to induce epigenetic modifications at target genes. Thus, it is conceivable that 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), a potent Ahr ligand, may elicit robust epigenetic changes in vivo at the Ahr target gene cytochrome P450 1a1 (Cyp1a1). A single dose of TCDD administered to adult mice induced Ahr-dependent CpG hypomethylation, changes in histone modifications, and thymine DNA glycosylase (Tdg) recruitment at the Cyp1a1 promoter in the liver within 24 hrs. These epigenetic changes persisted until 40 days post-TCDD treatment and there was Cyp1a1 mRNA hyperinduction upon repeat administration of TCDD at this time-point. Our demethylation assay using siRNA knockdown and an in vitro methylated plasmid showed that Ahr, Tdg, and the ten-eleven translocation methyldioxygenases Tet2 and Tet3 are required for the TCDD-induced DNA demethylation. These results provide novel evidence of Ahr-driven active DNA demethylation and epigenetic memory. The epigenetic alterations influence response to subsequent chemical exposure and imply an adaptive mechanism to xenobiotic stress.

  14. Role of zebrafish cytochrome P450 CYP1C genes in the reduced mesencephalic vein blood flow caused by activation of AHR2

    SciTech Connect

    Kubota, Akira; Stegeman, John J.; Woodin, Bruce R.; Iwanaga, Toshihiko; Harano, Ryo; Peterson, Richard E.; Hiraga, Takeo; Teraoka, Hiroki

    2011-06-15

    2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) causes various signs of toxicity in early life stages of vertebrates through activation of the aryl hydrocarbon receptor (AHR). We previously reported a sensitive and useful endpoint of TCDD developmental toxicity in zebrafish, namely a decrease in blood flow in the dorsal midbrain, but downstream genes involved in the effect are not known. The present study addressed the role of zebrafish cytochrome P450 1C (CYP1C) genes in association with a decrease in mesencephalic vein (MsV) blood flow. The CYP1C subfamily was recently discovered in fish and includes the paralogues CYP1C1 and CYP1C2, both of which are induced via AHR2 in zebrafish embryos. We used morpholino antisense oligonucleotides (MO or morpholino) to block initiation of translation of the target genes. TCDD-induced mRNA expression of CYP1Cs and a decrease in MsV blood flow were both blocked by gene knockdown of AHR2. Gene knockdown of CYP1C1 by two different morpholinos and CYP1C2 by two different morpholinos, but not by their 5 nucleotide-mismatch controls, was effective in blocking reduced MsV blood flow caused by TCDD. The same CYP1C-MOs prevented reduction of blood flow in the MsV caused by {beta}-naphthoflavone (BNF), representing another class of AHR agonists. Whole-mount in situ hybridization revealed that mRNA expression of CYP1C1 and CYP1C2 was induced by TCDD most strongly in branchiogenic primordia and pectoral fin buds. In situ hybridization using head transverse sections showed that TCDD increased the expression of both CYP1Cs in endothelial cells of blood vessels, including the MsV. These results indicate a potential role of CYP1C1 and CYP1C2 in the local circulation failure induced by AHR2 activation in the dorsal midbrain of the zebrafish embryo. - Research Highlights: > We examine the roles of zebrafish CYP1C1 and CYP1C2 in TCDD developmental toxicity. > TCDD induces mRNA expression of both CYP1Cs in the mesencephalic vein. > Knockdown of each

  15. Inhibition of the aryl hydrocarbon receptor prevents Western diet-induced obesity. Model for AHR activation by kynurenine via oxidized-LDL, TLR2/4, TGFβ, and IDO1.

    PubMed

    Moyer, Benjamin J; Rojas, Itzel Y; Kerley-Hamilton, Joanna S; Hazlett, Haley F; Nemani, Krishnamurthy V; Trask, Heidi W; West, Rachel J; Lupien, Leslie E; Collins, Alan J; Ringelberg, Carol S; Gimi, Barjor; Kinlaw, William B; Tomlinson, Craig R

    2016-06-01

    Obesity is an increasingly urgent global problem, yet, little is known about its causes and less is known how obesity can be effectively treated. We showed previously that the aryl hydrocarbon receptor (AHR) plays a role in the regulation of body mass in mice fed Western diet. The AHR is a ligand-activated nuclear receptor that regulates genes involved in a number of biological pathways, including xenobiotic metabolism and T cell polarization. This study was an investigation into whether inhibition of the AHR prevents Western diet-based obesity. Male C57Bl/6J mice were fed control and Western diets with and without the AHR antagonist α-naphthoflavone or CH-223191, and a mouse hepatocyte cell line was used to delineate relevant cellular pathways. Studies are presented showing that the AHR antagonists α-naphthoflavone and CH-223191 significantly reduce obesity and adiposity and ameliorates liver steatosis in male C57Bl/6J mice fed a Western diet. Mice deficient in the tryptophan metabolizing enzyme indoleamine 2,3-dioxygenase 1 (IDO1) were also resistant to obesity. Using an AHR-directed, luciferase-expressing mouse hepatocyte cell line, we show that the transforming growth factor β1 (TGFβ1) signaling pathway via PI3K and NF-κB and the toll-like receptor 2/4 (TLR2/4) signaling pathway stimulated by oxidized low-density lipoproteins via NF-κB, each induce luciferase expression; however, TLR2/4 signaling was significantly reduced by inhibition of IDO1. At physiological levels, kynurenine but not kynurenic acid (both tryptophan metabolites and known AHR agonists) activated AHR-directed luciferase expression. We propose a hepatocyte-based model, in which kynurenine production is increased by enhanced IDO1 activity stimulated by TGFβ1 and TLR2/4 signaling, via PI3K and NF-κB, to perpetuate a cycle of AHR activation to cause obesity; and inhibition of the AHR, in turn, blocks the cycle's output to prevent obesity. The AHR with its broad ligand binding specificity

  16. Synergistic induction of AHR regulated genes in developmental toxicity from co-exposure to two model PAHs in zebrafish

    PubMed Central

    Timme-Laragy, Alicia. R.; Cockman, Crystal. J.; Matson, Cole. W.; Di Giulio, Richard. T.

    2007-01-01

    Polycyclic aromatic hydrocarbons (PAHs) are pollutants created by the incomplete combustion of carbon, and are increasing in the environment largely due to the burning of fossil fuels. PAHs occur as complex mixtures, and some combinations have been shown to cause synergistic developmental toxicity in fish embryos, characterized by pericardial edema and craniofacial malformations. Previous studies have indicated that in the zebrafish model, this toxicity is mediated by the aryl hydrocarbon receptor 2 (AHR2), and enhanced by inhibition of CYP1A activity. In this study, we further examined this interaction of the model PAH and AHR agonist β-naphthoflavone (BNF) with and without the AHR partial agonist/antagonist and CYP1A inhibitor α-naphthoflavone (ANF) to determine 1) whether ANF was acting as an AHR antagonist, 2) what alterations BNF and ANF both alone and in combination had on mRNA expression of the AHR regulated genes cytochrome P450 (cyp) 1a, 1b1, and 1c1, and the AHR repressor (ahrr2) prior to vs. during deformity onset, and 3) compare CYP1A enzyme activity with mRNA induction. Zebrafish embryos were exposed from 24–48 or 24–96 hpf to BNF, 1–100 μg/L, ANF, 1–150 μg/L, a BNF+ANF co-exposure (1 μg/L + 100 μg/L), or a DMSO solvent control. RNA was extracted and examined by quantitative real time PCR. Both BNF and ANF each individually resulted in a dose dependent increase CYP1A, CYP1B1, CYP1C1, and AHRR2 mRNA, confirming their activities as AHR agonists. In the BNF+ANF co-exposures prior to deformity onset, expression of these genes was synergistic, and expression levels of the AHR regulated genes resembled the higher doses of BNF alone. Gene induction during deformities was also significantly increased in the co-exposure, but to a lesser magnitude than prior to deformity onset. EROD measurements of CYP1A activity showed ANF inhibited activity induction by BNF in the co-exposure group; this finding is not predicted by mRNA expression, which is

  17. The circadian clock circuitry and the AHR signaling pathway in physiology and pathology.

    PubMed

    Anderson, George; Beischlag, Timothy V; Vinciguerra, Manlio; Mazzoccoli, Gianluigi

    2013-05-15

    Life forms populating the Earth must face environmental challenges to assure individual and species survival. The strategies predisposed to maintain organismal homeostasis and grant selective advantage rely on anticipatory phenomena facing periodic modifications, and compensatory phenomena facing unpredictable changes. Biological processes bringing about these responses are respectively driven by the circadian timing system, a complex of biological oscillators entrained to the environmental light/dark cycle, and by regulatory and metabolic networks that precisely direct the body's adjustments to variations of external conditions and internal milieu. A critical role in organismal homeostatic functions is played by the aryl hydrocarbon receptor (AHR) complex, which senses environmental and endogenous compounds, influences metabolic responses controlling phase I/II gene expression, and modulates vital phenomena such as development, inflammation and adaptive immunity. A physiological cross-talk between circadian and AHR signaling pathways has been evidenced. The alteration of AHR signaling pathway deriving from genetic damage with polymorphisms or mutations, or produced by exogenous or endogenous AHR activation, and chronodisruption caused by mismatch between the body's internal clock and geophysical time/social schedules, are capable of triggering pathological mechanisms involved in metabolic, immune-related and neoplastic diseases. On the other hand, the molecular components of the circadian clock circuitry and AHR signaling pathway may represent useful tools for preventive interventions and valuable targets of therapeutic approaches.

  18. Genetic and pharmacological analysis identifies a physiological role for the AHR in epidermal differentiation

    PubMed Central

    van den Bogaard, Ellen; Podolsky, Michael; Smits, Jos; Cui, Xiao; John, Christian; Gowda, Krishne; Desai, Dhimant; Amin, Shantu; Schalkwijk, Joost; Perdew, Gary H.

    2015-01-01

    Stimulation of the aryl hydrocarbon receptor (AHR) by xenobiotics is known to affect epidermal differentiation and skin barrier formation. The physiological role of endogenous AHR signaling in keratinocyte differentiation is not known. We used murine and human skin models to address the hypothesis that AHR activation is required for normal keratinocyte differentiation. Using transcriptome analysis of Ahr-/- and Ahr+/+ murine keratinocytes, we found significant enrichment of differentially expressed genes linked to epidermal differentiation. Primary Ahr-/- keratinocytes showed a significant reduction in terminal differentiation gene and protein expression, similar to Ahr+/+ keratinocytes treated with AHR antagonists GNF351 and CH223191, or the selective AHR modulator (SAhRM), SGA360. In vitro keratinocyte differentiation led to increased AHR levels and subsequent nuclear translocation, followed by induced CYP1A1 gene expression. Monolayer cultured primary human keratinocytes treated with AHR antagonists also showed an impaired terminal differentiation program. Inactivation of AHR activity during human skin equivalent development severely impaired epidermal stratification, terminal differentiation protein expression and stratum corneum formation. As disturbed epidermal differentiation is a main feature of many skin diseases, pharmacological agents targeting AHR signaling or future identification of endogenous keratinocyte-derived AHR ligands should be considered as potential new drugs in dermatology. PMID:25602157

  19. Cytochrome P4501A induction in avian hepatocyte cultures exposed to polychlorinated biphenyls: Comparisons with AHR1-mediated reporter gene activity and in ovo toxicity

    SciTech Connect

    Manning, Gillian E.; Mundy, Lukas J.; Crump, Doug; Jones, Stephanie P.; Chiu, Suzanne; Klein, Jeff; Konstantinov, Alex; Potter, Dave; Kennedy, Sean W.

    2013-01-01

    Avian-specific toxic equivalency factors (TEFs) were developed by the World Health Organization to simplify environmental risk assessments of dioxin-like compounds (DLCs), but TEFs do not account for differences in the toxic and biochemical potencies of DLCs among species of birds. Such variability may be due to differences in species sensitivity to individual DLCs. The sensitivity of avian species to DLCs was recently associated with the identity of amino acids 324 and 380 in the aryl hydrocarbon receptor 1 (AHR1) ligand binding domain. A luciferase reporter gene (LRG) assay, measuring AHR1-mediated induction of a cytochrome P450 1A5 (CYP1A5) reporter gene, in combination with a species' AHR1 ligand binding domain sequence, were also shown to predict avian species sensitivity to polychlorinated biphenyls (PCBs) and PCB relative potency in a given species. The goals of the present study were to (1) characterize the concentration-dependent effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin and PCBs 126, 77, 105 and 118 on induction of ethoxyresorufin O-deethylase (EROD) activity and CYP1A4/5 mRNA in chicken, ring-necked pheasant and Japanese quail embryo hepatocytes and (2) compare these in vitro results to those previously generated by the LRG assay and in ovo toxicity studies. EROD activity and CYP1A4/5 mRNA expression data support and complement the findings of the LRG assay. CYP1A enzyme activity and mRNA expression were significantly correlated both with luciferase activity and in ovo toxicity induced by PCBs. Relative potency values were generally similar between the LRG and EROD assays and indicate that the relative potency of some PCBs may differ among species. -- Highlights: ► The chicken isn't the most sensitive species to CYP1A induction by PCB 105 and 118. ► The relative potency of PCBs differs between avian species. ► EROD activity was correlated with luciferase activity from the LRG assay. ► EROD activity was a better predictor of toxicity than CYP

  20. AHR signaling in prostate growth, morphogenesis, and disease

    PubMed Central

    Vezina, Chad M.; Lin, Tien-Min; Peterson, Richard E.

    2010-01-01

    Most evidence of aryl hydrocarbon receptor (AHR) signaling in prostate growth, morphogenesis, and disease stems from research using 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) to pharmacologically activate the AHR at various stages of development. This review discusses effects of TCDD on prostate morphogenesis and highlights interactions between AHR and other signaling pathways during normal and aberrant prostate growth. Although AHR signaling modulates estrogen and androgen signaling in other tissues, crosstalk between these steroid hormone receptors and AHR signaling cannot account for actions of TCDD on prostate morphogenesis. Instead, the AHR appears to act within a cooperative framework of developmental signals to regulate timing and patterning of prostate growth. Inappropriate activation of AHR signaling as a result of early life TCDD exposure disrupts the balance of these signals, impairs prostate morphogenesis, and has an imprinting effect on the developing prostate that predisposes to prostate disease in adulthood. Mechanisms of AHR signaling in prostate growth and disease are only beginning to be unraveled and recent studies have revealed its interactions with WNT5A, retinoic acid, fibroblast growth factor 10, and vascular endothelial growth factor signaling pathways. PMID:18977204

  1. Aryl hydrocarbon receptor (AhR) activation during pregnancy, and in adult nulliparous mice, delays the subsequent development of DMBA-induced mammary tumors

    PubMed Central

    Wang, Tao; Gavin, Heather M.; Arlt, Volker M.; Lawrence, B. Paige; Fenton, Suzanne E.; Medina, Daniel; Vorderstrasse, Beth A.

    2010-01-01

    TCDD (2,3,7,8-tetrachlorodibenzo-p-dioxin), the prototypic ligand for the aryl hydrocarbon receptor (AhR), promotes tumor formation in some model systems. However with regard to breast cancer, epidemiological and animal studies are inconclusive as to whether exposure increases tumor incidence or may instead be protective. We have previously reported that mice exposed to TCDD during pregnancy have impaired differentiation of mammary tissue, including decreased branching and poor development of lobuloalveolar structures. Because normal pregnancy-induced mammary differentiation may protect against subsequent neoplastic transformation, we hypothesized that TCDD-treated mice would be more susceptible to chemical carcinogenesis after parturition. To test this, mice were treated with TCDD or vehicle during pregnancy. Four weeks later, DMBA (7,12-dimethylbenz[a]anthracene) was administered to induce mammary tumor formation. Contrary to our hypothesis, TCDD-exposed parous mice showed a four-week delay in tumor formation relative to controls, and had a lower tumor incidence throughout the 27-week time course. The same results were obtained in nulliparous mice given TCDD and DMBA on the same schedule. We next addressed whether the delayed tumor incidence was a reflection of decreased tumor initiation, by testing the formation of DMBA-DNA adducts and preneoplastic lesions, induction of cytochrome P450s, and cell proliferation. None of these markers of tumor initiation differed between vehicle- and TCDD-treated animals. The expression of CXCL12 and CXCR4 was also measured to address their possible role in tumorigenesis. Taken together, our results suggest that AhR activation by TCDD slows the promotion of preneoplastic lesions to overt mammary tumors. PMID:20521247

  2. AhR activation by 6-formylindolo[3,2-b]carbazole and 2,3,7,8-tetrachlorodibenzo-p-dioxin inhibit the development of mouse intestinal epithelial cells.

    PubMed

    Park, Joo-Hung; Choi, Ah-Jeong; Kim, Soo-Ji; Cheong, Seon-Woo; Jeong, So-Yeon

    2016-04-01

    The intestinal epithelium plays a central role in immune homeostasis in the intestine. AhR, a ligand-activated transcription factor, plays an important role in diverse physiological processes. The intestines are exposed to various exogenous and endogenous AhR ligands. Thus, AhR may regulate the intestinal homeostasis, directly acting on the development of intestinal epithelial cells (IEC). In this study, we demonstrated that 6-formylindolo[3,2-b]carbazole (FICZ) and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) inhibited the in vitro development of mouse intestinal organoids. The number of Paneth cells in the small intestine and the depth of crypts of the small and large intestines were reduced in mice administrated with FICZ. Immunohistochemical and flow cytometric assays revealed that AhR was highly expressed in Lgr5(+) stem cells. FICZ inhibited Wnt signaling lowering the level of β-catenin protein. Gene expression analyses demonstrated that FICZ increased expression of Lgr5, Math1, BMP4, and Indian Hedgehog while inhibiting that of Lgr4. PMID:26950395

  3. AHR-related activities in a creosote-adapted population of adult atlantic killifish, Fundulus heteroclitus, two decades post-EPA superfund status at the Atlantic Wood Site, Portsmouth, VA USA.

    PubMed

    Wojdylo, Josephine V; Vogelbein, Wolfgang; Bain, Lisa J; Rice, Charles D

    2016-08-01

    Atlantic killifish, Fundulus heteroclitus, are adapted to creosote-based PAHs at the US EPA Superfund site known as Atlantic Wood (AW) on the southern branch of the Elizabeth River, VA USA. Subsequent to the discovery of the AW population in the early 1990s, these fish were shown to be recalcitrant to CYP1A induction by PAHs under experimental conditions, and even to the time of this study, killifish embryos collected from the AW site are resistant to developmental deformities typically associated with exposure to PAHs in reference fish. Historically, however, 90 +% of the adult killifish at this site have proliferative hepatic lesions including cancer of varying severity. Several PAHs at this site are known to be ligands for the aryl hydrocarbon receptor (AHR). In this study, AHR-related activities in AW fish collected between 2011 and 2013 were re-examined nearly 2 decades after first discovery. This study shows that CYP1A mRNA expression is three-fold higher in intestines of AW killifish compared to a reference population. Using immunohistochemistry, CYP1A staining in intestines was uniformly positive compared to negative staining in reference fish. Livers of AW killifish were examined by IHC to show that CYP1A and AHR2 protein expression reflect lesions-specific patterns, probably representing differences in intrinsic cellular physiology of the spectrum of proliferative lesions comprising the hepatocarcinogenic process. We also found that COX2 mRNA expression levels were higher in AW fish livers compared to those in the reference population, suggesting a state of chronic inflammation. Overall, these findings suggest that adult AW fish are responsive to AHR signaling, and do express CYP1A and AHR2 proteins in intestines at a level above what was observed in the reference population. PMID:27262937

  4. TCDD and omeprazole prime platelets through the aryl hydrocarbon receptor (AhR) non-genomic pathway.

    PubMed

    Pombo, Mónica; Lamé, Michael W; Walker, Naomi J; Huynh, Danh H; Tablin, Fern

    2015-05-19

    The role of the aryl hydrocarbon receptor (AhR) in hemostasis has recently gained increased attention. Here, we demonstrate, by qRT-PCR and western blot, that human platelets express both AhR mRNA and AhR protein. AhR protein levels increase in a dose dependent manner when incubated with either 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) or omeprazole. Treatment of platelets with puromycin blocks increased AhR protein synthesis in the presence of AhR activators. Additionally, treatment of platelets with either activator results in phosphorylation of p38MAPK and cPLA2, two key signaling molecules in platelet activation pathways. Using the AhR competitive inhibitors alpha naphthoflavone and CH-223191, we show that phosphorylation of p38MAPK is AhR dependent. Further, inhibition of p38MAPK blocks downstream cPLA2 phosphorylation induced by TCDD or omeprazole. Treatment with AhR activators results in platelet priming, as demonstrated by increased platelet aggregation, which is inhibited by AhR antagonists. Our data support a model of the platelet AhR non-genomic pathway in which treatment with AhR activators results in increased expression of the AhR, phosphorylation of p38MAPK and cPLA2, leading to platelet priming in response to agonist. PMID:25797602

  5. Alteration of human hepatic drug transporter activity and expression by cigarette smoke condensate.

    PubMed

    Sayyed, Katia; Vee, Marc Le; Abdel-Razzak, Ziad; Jouan, Elodie; Stieger, Bruno; Denizot, Claire; Parmentier, Yannick; Fardel, Olivier

    2016-07-01

    Smoking is well-known to impair pharmacokinetics, through inducing expression of drug metabolizing enzymes. In the present study, we demonstrated that cigarette smoke condensate (CSC) also alters activity and expression of hepatic drug transporters, which are now recognized as major actors of hepatobiliary elimination of drugs. CSC thus directly inhibited activities of sinusoidal transporters such as OATP1B1, OATP1B3, OCT1 and NTCP as well as those of canalicular transporters like P-glycoprotein, MRP2, BCRP and MATE1, in hepatic transporters-overexpressing cells. CSC similarly counteracted constitutive OATP, NTCP and OCT1 activities in human highly-differentiated hepatic HepaRG cells. In parallel, CSC induced expression of BCRP at both mRNA and protein level in HepaRG cells, whereas it concomitantly repressed mRNA expression of various transporters, including OATP1B1, OATP2B1, OAT2, NTCP, OCT1 and BSEP, and enhanced that of MRP4. Such changes in transporter gene expression were found to be highly correlated to those caused by 2,3,7,8-tetrachlorodibenzo-p-dioxin, a reference activator of the aryl hydrocarbon receptor (AhR) pathway, and were counteracted, for some of them, by siRNA-mediated AhR silencing. This suggests that CSC alters hepatic drug transporter levels via activation of the AhR cascade. Importantly, drug transporter expression regulations as well as some transporter activity inhibitions occurred for a range of CSC concentrations similar to those required for inducing drug metabolizing enzymes and may therefore be hypothesized to be relevant for smokers. Taken together, these data established human hepatic transporters as targets of cigarette smoke, which could contribute to known alteration of pharmacokinetics and some liver adverse effects caused by smoking. PMID:27450509

  6. AHR promoter variant modulates its transcription and downstream effectors by allele-specific AHR-SP1 interaction functioning as a genetic marker for vitiligo.

    PubMed

    Wang, Xiaowen; Li, Kai; Liu, Ling; Shi, Qiong; Song, Pu; Jian, Zhe; Guo, Sen; Wang, Gang; Li, Chunying; Gao, Tianwen

    2015-09-15

    Vitiligo is an acquired depigmentation disorder largely caused by defective melanocyte- or autoimmunity-induced melanocyte destruction. The aryl hydrocarbon receptor (AHR) is essential for melanocyte homeostasis and immune process, and abnormal AHR was observed in vitiligo. We previously identified the T allele of AHR -129C > T variant as a protective factor against vitiligo. However, biological characterization underlying such effects is not fully certain, further validation by mechanistic research is warranted and was conducted in the present study. We showed that -129T allele promoted AHR transcriptional activity through facilitating its interaction with SP1 transcription factor (SP1) compared with -129C allele. We subsequently found reduced peripheral AHR and SP1 transcript expressions in vitiligo and a negative correlation of AHR level with disease duration. We also investigated AHR-related cytokines and observed increased serum TNF-α concentration and diminished serum levels of IL-10 and TGF-β1 in vitiligo. Further genetic analysis showed that -129T carriers possessed higher levels of AHR and IL-10 than -129C carriers. Therefore, our study indicates that the modulation of AHR transcription by a promoter variant has a profound influence on vitiligo, not only advancing our understanding on AHR function but also providing novel insight into the pathogenesis of degenerative or autoimmune diseases including vitiligo.

  7. AHR promoter variant modulates its transcription and downstream effectors by allele-specific AHR-SP1 interaction functioning as a genetic marker for vitiligo

    PubMed Central

    Wang, Xiaowen; Li, Kai; Liu, Ling; Shi, Qiong; Song, Pu; Jian, Zhe; Guo, Sen; Wang, Gang; Li, Chunying; Gao, Tianwen

    2015-01-01

    Vitiligo is an acquired depigmentation disorder largely caused by defective melanocyte- or autoimmunity-induced melanocyte destruction. The aryl hydrocarbon receptor (AHR) is essential for melanocyte homeostasis and immune process, and abnormal AHR was observed in vitiligo. We previously identified the T allele of AHR −129C > T variant as a protective factor against vitiligo. However, biological characterization underlying such effects is not fully certain, further validation by mechanistic research is warranted and was conducted in the present study. We showed that −129T allele promoted AHR transcriptional activity through facilitating its interaction with SP1 transcription factor (SP1) compared with −129C allele. We subsequently found reduced peripheral AHR and SP1 transcript expressions in vitiligo and a negative correlation of AHR level with disease duration. We also investigated AHR-related cytokines and observed increased serum TNF-α concentration and diminished serum levels of IL-10 and TGF-β1 in vitiligo. Further genetic analysis showed that -129T carriers possessed higher levels of AHR and IL-10 than −129C carriers. Therefore, our study indicates that the modulation of AHR transcription by a promoter variant has a profound influence on vitiligo, not only advancing our understanding on AHR function but also providing novel insight into the pathogenesis of degenerative or autoimmune diseases including vitiligo. PMID:26370050

  8. Behavioral Rhythmicity of Mice Lacking AhR and Attenuation of Light-induced Phase Shift by 2,3,7,8-Tetracholordibenzo-p-dioxin

    PubMed Central

    Mukai, Motoko; Lin, Tien-Min; Peterson, Richard E.; Cooke, Paul S.; Tischkau, Shelley A.

    2008-01-01

    Transcription factors belonging to the Per/Arnt/Sim (PAS) domain family are highly conserved and many are involved in circadian rhythm regulation. One member of this family, aryl hydrocarbon receptor (AhR), is an orphan receptor whose physiological role is unknown. Recent findings have led to the hypothesis that AhR has a role in circadian rhythm, which is the focus of the present investigation. First, time-of-day dependent mRNA expression of AhR and its signaling target, cytochrome p4501A1 (Cyp1a1) was determined in C57BL/6J mice by quantitative RT-PCR. Circadian expression of AhR and Cyp1a1 was observed both in the suprachiasmatic nucleus (SCN) and liver. Next, the circadian phenotype of mice lacking AhR (AhRKO) was investigated using behavioral monitoring. Intact AhRKO mice had robust circadian rhythmicity with a similar tau under constant conditions compared to wild-type mice, but a significant difference in tau was observed between genotypes in ovariectomized female mice. Time to re-entrainment following 6-h advances or delays of the light/dark cycle was not significantly different between genotypes. However, mice exposed to the AhR agonist 2,3,7,8-tetracholorodibenzo-p-dioxin (TCDD, 1 μg/kg BW) displayed decreased phase shifts in response to light and had altered expression of Per1 and Bmal1. These results suggest that chronic activation of AhR may affect the ability of the circadian timekeeping system to adjust to alterations in environmental lighting by affecting canonical clock genes. Further studies are necessary to decipher the mechanism of how AhR agonists could disrupt light-induced phase shifts. If AhR does have a role in circadian rhythm, it may share redundant roles with other PAS domain proteins and/or the role of AhR may not be exhibited in the behavioral activity rhythm, but could be important elsewhere in the peripheral circadian system. PMID:18487412

  9. A novel AhR ligand, 2AI, protects the retina from environmental stress

    PubMed Central

    Gutierrez, Mark A.; Davis, Sonnet S.; Rosko, Andrew; Nguyen, Steven M.; Mitchell, Kylie P.; Mateen, Samiha; Neves, Joana; Garcia, Thelma Y.; Mooney, Shaun; Perdew, Gary H.; Hubbard, Troy D.; Lamba, Deepak A.; Ramanathan, Arvind

    2016-01-01

    Various retinal degenerative diseases including dry and neovascular age-related macular degeneration (AMD), retinitis pigmentosa, and diabetic retinopathy are associated with the degeneration of the retinal pigmented epithelial (RPE) layer of the retina. This consequently results in the death of rod and cone photoreceptors that they support, structurally and functionally leading to legal or complete blindness. Therefore, developing therapeutic strategies to preserve cellular homeostasis in the RPE would be a favorable asset in the clinic. The aryl hydrocarbon receptor (AhR) is a conserved, environmental ligand-dependent, per ARNT-sim (PAS) domain containing bHLH transcription factor that mediates adaptive response to stress via its downstream transcriptional targets. Using in silico, in vitro and in vivo assays, we identified 2,2′-aminophenyl indole (2AI) as a potent synthetic ligand of AhR that protects RPE cells in vitro from lipid peroxidation cytotoxicity mediated by 4-hydroxynonenal (4HNE) as well as the retina in vivo from light-damage. Additionally, metabolic characterization of this molecule by LC-MS suggests that 2AI alters the lipid metabolism of RPE cells, enhancing the intracellular levels of palmitoleic acid. Finally, we show that, as a downstream effector of 2AI-mediated AhR activation, palmitoleic acid protects RPE cells from 4HNE-mediated stress, and light mediated retinal degeneration in mice. PMID:27364765

  10. AHR-5850: a potent anti-inflammatory compound.

    PubMed

    Sancilio, L F; Reese, D L; Cheung, S; Alphin, R S

    1977-03-01

    AHR-5850 is a non-steroidal anti-inflammatory compound possessing antipyretic and analgesic properties. AHR-5850 was 16.4 and 22.8 times more potent than phenylbutazone in suppressing acute (Evans blue-carrageenan pleural effusion) and chronic (adjuvant-induced arthritis) inflammation, respectively. The analgesic activity of AHR 5850 was 43 times that of acetylsalicylic acid in the Randall-Selitto assay, and 156 and 56.3 times more potent than phenylbutazone in the acetylcholine-induced abdominal constriction in mice and in the bradykinin-induced nociceptive response in dogs, respectively. Single-dose studies showed that AHR-5850 produced less gastric irritation than acetylsalicylic acid when applied topically to the exposed gastric mucosa of cats or when administered orally to rats and dogs. Upon subchronic oral administration to rats, the therapeutic ratio of AHR-5850 was twice that of phenylbutazone. This was based on the ratio of its potency relative to phenylbutazone in producing intestinal lesions to its anti-inflammatory potency relative to phenylbutazone in the adjuvant-induced arthritis.

  11. Aromatic hydrocarbons upregulate glyceraldehyde-3-phosphate dehydrogenase and induce changes in actin cytoskeleton. Role of the aryl hydrocarbon receptor (AhR).

    PubMed

    Reyes-Hernández, O D; Mejía-García, A; Sánchez-Ocampo, E M; Castro-Muñozledo, F; Hernández-Muñoz, R; Elizondo, G

    2009-12-21

    Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is a multifunctional enzyme involved in several cellular functions including glycolysis, membrane transport, microtubule assembly, DNA replication and repair, nuclear RNA export, apoptosis, and the detection of nitric oxide stress. Therefore, modifications in the regulatory ability and function of GAPDH may alter cellular homeostasis. We report here that 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and beta-naphthoflavone, which are well-known ligands for the aryl hydrocarbon receptor (AhR), increase GAPDH mRNA levels in vivo and in vitro, respectively. These compounds fail to induce GAPDH transcription in an AhR-null mouse model, suggesting that the increase in GAPDH level is dependent upon AhR activation. To analyse the consequences of AhR ligands on GAPDH function, mice were treated with TCDD and the level of liver activity of GAPDH was determined. The results showed that TCDD treatment increased GAPDH activity. On the other hand, treatment of Hepa-1 cells with beta-naphthoflavone leads to an increase in microfilament density when compared to untreated cultures. Collectively, these results suggest that AhR ligands, such as polycyclic hydrocarbons, can modify GAPDH expression and, therefore, have the potential to alter the multiple functions of this enzyme.

  12. 2,3,7,8-Tetrachlorodibenzo-p-dioxin activates the aryl hydrocarbon receptor and alters sex steroid hormone secretion without affecting growth of mouse antral follicles in vitro

    SciTech Connect

    Karman, Bethany N. Basavarajappa, Mallikarjuna S. Craig, Zelieann R. Flaws, Jodi A.

    2012-05-15

    The persistent environmental contaminant, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) is an ovarian toxicant. These studies were designed to characterize the actions of TCDD on steroidogenesis and growth of intact mouse antral follicles in vitro. Specifically, these studies tested the hypothesis that TCDD exposure leads to decreased sex hormone production/secretion by antral follicles as well as decreased growth of antral follicles in vitro. Since TCDD acts through binding to the aryl hydrocarbon receptor (AHR), and the AHR has been identified as an important factor in ovarian function, we also conducted experiments to confirm the presence and activation of the AHR in our tissue culture system. To do so, we exposed mouse antral follicles for 96 h to a series of TCDD doses previously shown to have effects on ovarian tissues and cells in culture, which also encompass environmentally relevant and pharmacological exposures (0.1–100 nM), to determine a dose response for TCDD in our culture system for growth, hormone production, and expression of the Ahr and Cyp1b1. The results indicate that TCDD decreases progesterone, androstenedione, testosterone, and estradiol levels in a non-monotonic dose response manner without altering growth of antral follicles. The addition of pregnenolone substrate (10 μM) restores hormone levels to control levels. Additionally, Cyp1b1 levels were increased by 3–4 fold regardless of the dose of TCDD exposure, evidence of AHR activation. Overall, these data indicate that TCDD may act prior to pregnenolone formation and through AHR transcriptional control of Cyp1b1, leading to decreased hormone levels without affecting growth of antral follicles. -- Highlights: ►TCDD disrupts sex steroid hormone levels, but not growth of antral follicles. ►Pregnenolone co-treatment by-passes TCDD-induced steroid hormone disruption. ►TCDD affects steroid hormone levels through an AHR pathway in antral follicles.

  13. Use of natural AhR ligands as potential therapeutic modalities against inflammatory disorders

    PubMed Central

    Busbee, Philip B; Rouse, Michael; Nagarkatti, Mitzi; Nagarkatti, Prakash S

    2014-01-01

    The aim of this review is to discuss research involving ligands for the aryl hydrocarbon receptor (AhR) and their role in immunomodulation. While activation of the AhR is well known for its ability to regulate the biochemical and toxic effects of environmental chemicals, more recently an exciting discovery has been made indicating that AhR ligation can also regulate T-cell differentiation, specifically through activation of Foxp3+ regulatory T cells (Tregs) and downregulation of the proinflammatory Th17 cells. Such findings have opened new avenues of research on the possibility of targeting the AhR to treat inflammatory and autoimmune diseases. Specifically, this review will discuss the current research involving natural and dietary AhR ligands. In addition, evidence indicating the potential use of these ligands in regulating inflammation in various diseases will be highlighted. The importance of the AhR in immunological processes can be illustrated by expression of this receptor on a majority of immune cell types. In addition, AhR signaling pathways have been reported to influence a number of genes responsible for mediating inflammation and other immune responses. As interest in the AhR and its ligands increases, it seems prudent to consolidate current research on the contributions of these ligands to immune regulation during the course of inflammatory diseases. PMID:23731446

  14. Trypanosoma cruzi trans-sialidase initiates an ROR-γt–AHR-independent program leading to IL-17 production by activated B cells

    PubMed Central

    Bermejo, Daniela A; Jackson, Shaun W; Gorosito-Serran, Melisa; Acosta-Rodriguez, Eva V; Amezcua-Vesely, Maria C; Sather, Blythe D; Singh, Akhilesh K.; Khim, Socheath; Mucci, Juan; Liggitt, Denny; Campetella, Oscar; Oukka, Mohamed; Gruppi, Adriana; Rawlings, David J

    2013-01-01

    We identified B cells as a major source for rapid, innate-like interleukin 17 (IL-17) production in vivo in response to Trypanosoma cruzi infection. IL-17+ B cells exhibited a plasmablast phenotype, outnumbered TH17 cells and were required for optimal response to this pathogen. Using both murine and human primary B cells, we demonstrate that exposure to parasite-derived trans-sialidase in vitro was sufficient to trigger modification of the cell surface mucin, CD45, leading to Btk-dependent signaling and IL-17A or IL-17F production via an ROR-γt and AHR-independent transcriptional program. Our combined data suggest that generation of IL-17+ B cells may be an unappreciated feature of innate immune responses required for pathogen control or IL-17-mediated autoimmunity. PMID:23563688

  15. Microarray analysis of the AHR system: Tissue-specific flexibility in signal and target genes

    SciTech Connect

    Frericks, Markus; Meissner, Marc; Esser, Charlotte . E-mail: chesser@uni-duesseldorf.de

    2007-05-01

    Data mining published microarray experiments require that expression profiles are directly comparable. We performed linear global normalization on the data of 1967 Affymetrix U74av2 microarrays, i.e. the transcriptomes of > 100 murine tissues or cell types. The mathematical transformation effectively nullifies inter-experimental or inter-laboratory differences between microarrays. The correctness of expression values was validated by quantitative RT-PCR. Using the database we analyze components of the aryl hydrocarbon receptor (AHR) signaling pathway in various tissues. We identified lineage and differentiation specific variant expression of AHR, ARNT, and HIF1{alpha} in the T-cell lineage and high expression of CYP1A1 in immature B cells and dendritic cells. Performing co-expression analysis we found unorthodox expression of the AHR in the absence of ARNT, particularly in stem cell populations, and can reject the hypothesis that ARNT2 takes over and is highly expressed when ARNT expression is low or absent. Furthermore the AHR shows no co-expression with any other transcript present on the chip. Analysis of differential gene expression under 308 conditions revealed 53 conditions under which the AHR is regulated, numerous conditions under which an intrinsic AHR action is modified as well as conditions activating the AHR even in the absence of known AHR ligands. Thus meta-analysis of published expression profiles is a powerful tool to gain novel insights into known and unknown systems.

  16. Combination effects of AHR agonists and Wnt/β-catenin modulators in zebrafish embryos: Implications for physiological and toxicological AHR functions

    SciTech Connect

    Wincent, Emma; Stegeman, John J.; Jönsson, Maria E.

    2015-04-15

    Wnt/β-catenin signaling regulates essential biological functions and acts in developmental toxicity of some chemicals. The aryl hydrocarbon receptor (AHR) is well-known to mediate developmental toxicity of persistent dioxin-like compounds (DLCs). Recent studies indicate a crosstalk between β-catenin and the AHR in some tissues. However the nature of this crosstalk in embryos is poorly known. We observed that zebrafish embryos exposed to the β-catenin inhibitor XAV939 display effects phenocopying those of the dioxin-like 3,3′,4,4′,5-pentachlorobiphenyl (PCB126). This led us to investigate the AHR interaction with β-catenin during development and ask whether developmental toxicity of DLCs involves antagonism of β-catenin signaling. We examined phenotypes and transcriptional responses in zebrafish embryos exposed to XAV939 or to a β-catenin activator, 1-azakenpaullone, alone or with AHR agonists, either PCB126 or 6-formylindolo[3,2-b]carbazole (FICZ). Alone 1-azakenpaullone and XAV939 both were embryo-toxic, and we found that in the presence of FICZ, the toxicity of 1-azakenpaullone decreased while the toxicity of XAV939 increased. This rescue of 1-azakenpaullone effects occurred in the time window of Ahr2-mediated toxicity and was reversed by morpholino-oligonucleotide knockdown of Ahr2. Regarding PCB126, addition of either 1-azakenpaullone or XAV939 led to lower mortality than with PCB126 alone but surviving embryos showed severe edemas. 1-Azakenpaullone induced transcription of β-catenin-associated genes, while PCB126 and FICZ blocked this induction. The data indicate a stage-dependent antagonism of β-catenin by Ahr2 in zebrafish embryos. We propose that the AHR has a physiological role in regulating β-catenin during development, and that this is one point of intersection linking toxicological and physiological AHR-governed processes.

  17. Combination effects of AHR agonists and Wnt/β-catenin modulators in zebrafish embryos: implications for physiological and toxicological AHR functions

    PubMed Central

    Wincent, Emma; Stegeman, John J.; Jönsson, Maria E.

    2016-01-01

    Wnt/β-catenin signaling regulates essential biological functions and acts in developmental toxicity of some chemicals. The aryl hydrocarbon receptor (AHR) is well-known to mediate developmental toxicity of persistent dioxin-like compounds (DLCs). Recent studies indicate a crosstalk between β-catenin and the AHR in some tissues. However the nature of this crosstalk in embryos is poorly known. We observed that zebrafish embryos exposed to the β-catenin inhibitor XAV939 display effects phenocopying those of the dioxin-like 3,3′,4,4′,5-pentachlorobiphenyl (PCB126). This led us to investigate AHR interaction with β-catenin during development and ask whether developmental toxicity of DLCs involves antagonism of β-catenin signaling. We examined phenotypes and transcriptional responses in zebrafish embryos exposed to XAV939 or to a β-catenin activator, 1-azakenpaullone, alone or with AHR agonists, either PCB126 or 6-formylindolo[3,2-b]carbazole (FICZ). Alone 1-azakenpaullone and XAV939 both were embryo-toxic, and we found that in presence of FICZ, the toxicity of 1-azakenpaullone decreased while the toxicity of XAV939 increased. This rescue of 1-azakenpaullone effects occurred in the time window of Ahr2-mediated toxicity and was reversed by morpholine-oligonucleotide knockdown of Ahr2. Regarding PCB126, addition of either 1-azakenpaullone or XAV939 led to lower mortality than with PCB126 alone but surviving embryos showed severe edemas. 1-Azakenpaullone induced transcription of β-catenin-associated genes, while PCB126 and FICZ blocked this induction. The data indicate a stage-dependent antagonism of β-catenin by Ahr2 in zebrafish embryos. We propose that the AHR has a physiological role in regulating β-catenin during development, and that this is one point of intersection linking toxicological and physiological AHR-governed processes. PMID:25711857

  18. Plant polyphenols differentially modulate inflammatory responses of human keratinocytes by interfering with activation of transcription factors NF{kappa}B and AhR and EGFR-ERK pathway

    SciTech Connect

    Potapovich, Alla I.; Lulli, Daniela; Fidanza, Paolo; Kostyuk, Vladimir A.; De Luca, Chiara; Pastore, Saveria; Korkina, Liudmila G.

    2011-09-01

    Molecular mechanisms underlying modulation of inflammatory responses in primary human keratinocytes by plant polyphenols (PPs), namely the glycosylated phenylpropanoid verbascoside, the stilbenoid resveratrol and its glycoside polydatin, and the flavonoid quercetin and its glycoside rutin were evaluated. As non-lethal stimuli, the prototypic ligand for epidermal growth factor receptor (EGFR) transforming growth factor alpha (TGFalpha), the combination of tumor necrosis factor (TNFalpha) and interferon (IFNgamma) (T/I), UVA + UVB irradiation, and bacterial lipopolysaccharide (LPS) were used. We demonstrated differential modulation of inflammatory responses in keratinocytes at signal transduction, gene transcription, and protein synthesis levels as a function of PP chemical structure, the pro-inflammatory trigger used, and PP interaction with intracellular detoxifying systems. The PPs remarkably inhibited constitutive, LPS- and T/I-induced but not TGFalpha-induced ERK phosphorylation. They also suppressed NFkappaB activation by LPS and T/I. Verbascoside and quercetin invariably impaired EGFR phosphorylation and UV-associated aryl hydrocarbon receptor (AhR)-mediated signaling, while rutin, polydatin and resveratrol did not affect EGFR phosphorylation and further activated AhR machinery in UV-exposed keratinocytes. In general, PPs down-regulated gene expression of pro-inflammatory cytokines/enzymes, except significant up-regulation of IL-8 observed under stimulation with TGFalpha. Both spontaneous and T/I-induced release of IL-8 and IP-10 was suppressed, although 50 {mu}M resveratrol and polydatin up-regulated IL-8. At this concentration, resveratrol activated both gene expression and de novo synthesis of IL-8 and AhR-mediated mechanisms were involved. We conclude that PPs differentially modulate the inflammatory response of human keratinocytes through distinct signal transduction pathways, including AhR and EGFR. - Graphical abstract: Display Omitted Highlights

  19. Alternative in vitro approach for assessing AHR-mediated CYP1A induction by dioxins in wild cormorant (Phalacrocorax carbo) population.

    PubMed

    Thuruthippallil, Leena Mol; Kubota, Akira; Kim, Eun-Young; Iwata, Hisato

    2013-06-18

    Our line of papers revealed that the common (great) cormorant (Phalacrocorax carbo) possesses two isoforms of the aryl hydrocarbon receptor (ccAHR1 and ccAHR2). This paper addresses in vitro tests of the ccAHR signaling pathways to solve two questions: (1) whether there are functional differences in the two ccAHR isoforms, and (2) whether a molecular perturbation, cytochrome P450 1A (ccCYP1A) induction, in the population-level can be predicted from the in vitro tests. The transactivation potencies mediated by ccAHR1 and ccAHR2 were measured in COS-7 cells treated with 15 selected dioxins and related compounds (DRCs), where ccAHR1 or ccAHR2 expression plasmid and ccCYP1A5 promoter/enhancer-linked luciferase reporter plasmid were transfected. For congeners that exhibited dose-dependent luciferase activities, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) relative potencies (REPs) and induction equivalency factors (IEFs) were estimated. ccAHR1-IEF profile was similar to WHO avian TCDD toxic equivalency factor (TEF) profile except for dioxin-like polychlorinated biphenyls that showed lower IEFs in ccAHR1-driven reporter assay. ccAHR2-IEF profile was different from WHO TEFs and ccAHR1-IEFs. Notably, 2,3,4,7,8-PeCDF was more potent than TCDD for ccAHR2-mediated response. Using ccAHR1- and ccAHR2-IEFs and hepatic DRC concentrations in the Lake Biwa cormorant population, total TCDD induction equivalents (IEQs) were calculated for each ccAHR-mediated response. Nonlinear regression analyses provided significant sigmoidal relationships of ccAHR1- and ccAHR2-derived IEQs with hepatic ccCYP1A5 mRNA levels, supporting the results of in vitro ccAHR-mediated TCDD dose-response curves. Collectively, our in vitro AHR reporter assay potentially could be an alternative to molecular epidemiology of the species of concern regarding CYP1A induction by AHR ligands. PMID:23676118

  20. Pityriazepin and other potent AhR ligands isolated from Malassezia furfur yeast

    PubMed Central

    Mexia, Nikitia; Gaitanis, George; Velegraki, Aristea; Soshilov, Anatoly; Denison, Michael S.; Magiatis, Prokopios

    2015-01-01

    Malassezia furfur yeast strains isolated from diseased human skin preferentially biosynthesize indole alkaloids which can be detected in human skin and are highly potent activators of the aryl hydrocarbon receptor (AhR) and AhR-dependent gene expression. Chemical analysis of an EtOAc extract of a M. furfur strain obtained from diseased human skin and grown on L-tryptophan agar revealed several known AhR active tryptophan metabolites along with a previously unidentified compound, pityriazepin. While its structure resembled that of the known alkaloid pityriacitrin, the comprised pyridine ring had been transformed into an azepinone. The indoloazepinone scaffold of pityriazepin is extremely rare in nature and has only been reported once previously. Pityriazepin, like the other isolated compounds, was found to be a potent activator of the AhR-dependent reporter gene assays in recombinant cell lines derived from four different species, although significant species differences in relative potency was observed. The ability of pityriazepin to competitively bind to the AhR and directly stimulate AhR DNA binding classified it as a new naturally-occurring potent AhR agonist. Malassezia furfur produces an expanded collection of extremely potent naturally occurring AhR agonists, which produce their biological effects in a species-specific manner.1 PMID:25721496

  1. Non-dioxin-like AhR ligands in a mouse peanut allergy model.

    PubMed

    Schulz, Veronica J; Smit, Joost J; Huijgen, Veerle; Bol-Schoenmakers, Marianne; van Roest, Manon; Kruijssen, Laura J W; Fiechter, Daniëlle; Hassing, Ine; Bleumink, Rob; Safe, Stephen; van Duursen, Majorie B M; van den Berg, Martin; Pieters, Raymond H H

    2012-07-01

    Recently, we have shown that AhR activation by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) suppresses sensitization to peanut at least in part by inducing a functional shift toward CD4(+)CD25(+)Foxp3(+) T cells. Next to TCDD, numerous other AhR ligands have been described. In this study, we investigated the effect of three structurally different non-dioxin-like AhR ligands, e.g., 6-formylindolo[3,2-b]carbazole (FICZ), β-naphthoflavone (β-NF), and 6-methyl-1,3,8-trichlorodibenzofuran (6-MCDF), on peanut sensitization. Female C57BL/6 mice were sensitized by administering peanut extract (PE) by gavage in the presence of cholera toxin. Before and during peanut sensitization, mice were treated with FICZ, β-NF, or 6-MCDF. AhR gene transcription in duodenum and liver was investigated on day 5, even as the effect of these AhR ligands on CD4(+)CD25(+)Foxp3(+) T(reg) cells in spleen and mesenteric lymph nodes (MLNs). Mice treated with TCDD were included as a positive control. Furthermore, the murine reporter cell line H1G1.1c3 (CAFLUX) was used to investigate the possible role of metabolism of TCDD, FICZ, β-NF, and 6-MCDF on AhR activation in vitro. TCDD, but not FICZ, β-NF, and 6-MCDF, suppressed sensitization to peanut (measured by PE-specific IgE, IgG1, IgG2a and PE-induced interleukin (IL)-5, IL-10, IL-13, IL-17a, IL-22, and interferon-γ). In addition, FICZ, β-NF, and 6-MCDF treatments less effectively induced AhR gene transcription (measured by gene expression of AhR, AhRR, CYP1A1, CYP1A2, CYP1B1) compared with TCDD-treated mice. Furthermore, FICZ, β-NF and 6-MCDF did not increase the percentage of CD4(+)CD25(+)Foxp3(+) T(reg) cells in spleen and mesenteric lymph nodes compared with PE-sensitized mice, in contrast to TCDD. Inhibition of metabolism in vitro increased AhR activation. Together, these data shows that TCDD, but not FICZ, β-NF, and 6-MCDF suppresses sensitization to peanut. Differences in metabolism, AhR binding and subsequent gene transcription might

  2. Aryl-hydrocarbon receptor activity modulates prolactin expression in the pituitary.

    PubMed

    Moran, Tyler B; Brannick, Katherine E; Raetzman, Lori T

    2012-11-15

    Pituitary tumors account for 15% of intracranial neoplasms, however the extent to which environmental toxicants contribute to the proliferation and hormone expression of pituitary cells is unknown. Aryl-hydrocarbon receptor (AhR) interacting protein (AIP) loss of function mutations cause somatotrope and lactotrope adenomas in humans. AIP sequesters AhR and inhibits its transcriptional function. Because of the link between AIP and pituitary tumors, we hypothesize that exposure to dioxins, potent exogenous ligands for AhR that are persistent in the environment, may predispose to pituitary dysfunction through activation of AhR. In the present study, we examined the effect of AhR activation on proliferation and endogenous pituitary hormone expression in the GH3 rat somatolactotrope tumor cell line and the effect of loss of AhR action in knockout mice. GH3 cells respond to nM doses of the reversible AhR agonist β-naphthoflavone with a robust induction of Cyp1a1. Although mRNA levels of the anti-proliferative signaling cytokine TGFbeta1 are suppressed upon β-naphthoflavone treatment, we did not observe an alteration in cell proliferation. AhR activation with β-naphthoflavone suppresses Ahr expression and impairs expression of prolactin (PRL), but not growth hormone (GH) mRNA in GH3 cells. In mice, loss of Ahr similarly leads to a reduction in Prl mRNA at P3, while Gh is unaffected. Additionally, there is a significant reduction in pituitary hormones Lhb and Fshb in the absence of Ahr. Overall, these results demonstrate that AhR is important for pituitary hormone expression and suggest that environmental dioxins can exert endocrine disrupting effects at the pituitary.

  3. Toxic effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in developing red seabream (Pagrus major) embryo: an association of morphological deformities with AHR1, AHR2 and CYP1A expressions.

    PubMed

    Yamauchi, Masanobu; Kim, Eun-Young; Iwata, Hisato; Shima, Yasuhiro; Tanabe, Shinsuke

    2006-11-16

    The toxicity of dioxins such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) is mainly mediated by the aryl hydrocarbon receptor (AHR), which regulates the multiple target genes including cytochrome P4501A (CYP1A). In general, bony fishes, which possess at least two distinct AHRs are one of the most sensitive vertebrates to TCDD in early life stage. However, the physiological and toxicological roles of piscine multiple AHRs are not fully understood, especially in marine fish. To understand which AHR is responsible for TCDD toxicity in a marine fish species, we characterized the early life stage toxicity related to the expression of AHRs and CYP1A in red seabream (Pagrus major). The embryos at 10h post-fertilization (hpf) were treated with 0-100 microg/L TCDD for 80 min waterborne exposure. TCDD dose-dependently elicited developmental toxicities including mortality, yolk sac edema, retarded body growth, spinal deformity, reduced heart rate, shortened snout, underdeveloped fin, heart, and lower jaw. Intriguingly, hemorrhage and pericardium edema, typical TCDD developmental defects noticed in other fish species, were not found in red seabream until test termination. The EC(egg)50s for yolk sac edema, underdeveloped fin, and spinal deformity were 170, 240, and 340 pg/g, respectively. The LC(egg)50 was 360 pg/g embryo, indicating that this species is one of the most sensitive fishes to TCDD toxicity. The expression levels of rsAHR1, rsAHR2 and CYP1A mRNAs were also determined in different developmental stages. The rsAHR2 mRNA expression dose-dependently increased following TCDD exposure, while rsAHR1 mRNA level was not altered. Level of rsAHR2 mRNA measured by two-step real-time PCR was 30 times higher than rsAHR1 in embryos treated with the highest dose. Temporal patterns of rsAHR2 and CYP1A mRNAs were similar in TCDD-treated embryos, representing a significant positive correlation between rsAHR2 and CYP1A mRNA levels, but not between rsAHR1 and CYP1A. In comparison of

  4. AHR2-Mediated Transcriptomic Responses Underlying the Synergistic Cardiac Developmental Toxicity of PAHs

    PubMed Central

    Jayasundara, Nishad; Van Tiem Garner, Lindsey; Meyer, Joel N.; Erwin, Kyle N.; Di Giulio, Richard T.

    2015-01-01

    Polycyclic aromatic hydrocarbons (PAHs) induce developmental defects including cardiac deformities in fish. The aryl hydrocarbon receptor (AHR) mediates the toxicity of some PAHs. Exposure to a simple PAH mixture during embryo development consisting of an AHR agonist (benzo(a)pyrene-BaP) with fluoranthene (FL), an inhibitor of cytochrome p450 1(CYP1)—a gene induced by AHR activation—results in cardiac deformities. Exposure to BaP or FL alone at similar concentrations alters heart rates, but does not induce morphological deformities. Furthermore, AHR2 knockdown prevents the toxicity of BaP + FL mixture. Here, we used a zebrafish microarray analysis to identify heart-specific transcriptomic changes during early development that might underlie cardiotoxicity of BaP + FL. We used AHR2 morphant embryos to determine the role of this receptor in mediating toxicity. Control and knockdown embryos at 36 h post-fertilization were exposed to DMSO, 100 μg/l BaP, 500 μg/l FL, or 100 μg/l BaP + 500 μg/l FL, and heart tissues for RNA were extracted at 2, 6, 12, and 18 h-post-exposure (hpe), prior to the appearance of cardiac deformities. Data show AHR2-dependent BaP + FL effects on expression of genes involved in protein biosynthesis and neuronal development in addition to signaling molecules and their associated molecular pathways. Ca2+-cycling and muscle contraction genes were the most significantly differentially expressed category of transcripts when comparing BaP + FL-treated AHR2 morphant and control embryos. These differences were most prominent at 2 and 6 hpe. Therefore, we postulate that BaP + FL may affect cellular Ca2+ levels and subsequently cardiac muscle function, potentially underlying BaP + FL cardiotoxicity. PMID:25412620

  5. The aryl hydrocarbon receptor (AHR) transcription factor regulates megakaryocytic polyploidization

    PubMed Central

    Lindsey, Stephan; T. Papoutsakis, Eleftherios

    2012-01-01

    Summary We propose that the aryl hydrocarbon receptor (AHR) is a novel transcriptional regulator of megakaryopoietic polyploidization. Functional evidence was obtained that AHR impacts in vivo megakaryocytic differentiation and maturation; compared to wild-type mice, AHR-null mice had lower platelet counts, fewer numbers of newly synthesized platelets, increased bleeding times and lower-ploidy megakaryocytes (Mks). AHR mRNA increased 3·6-fold during ex vivo megakaryocytic differentiation, but reduced or remained constant during parallel isogenic granulocytic or erythroid differentiation. We interrogated the role of AHR in megakaryopoiesis using a validated Mk model of megakaryopoiesis, the human megakaryoblastic leukaemia CHRF cell line. Upon CHRF Mk differentiation, AHR mRNA and protein levels increased, AHR protein shifted from the cytoplasm to the nucleus and AHR binding to its consensus DNA binding sequence increased. Protein and mRNA levels of the AHR transcriptional target HES1 also increased. Mk differentiation of CHRF cells where AHR or HES1 was knocked-down using RNAi resulted in lower ploidy distributions and cells that were incapable of reaching ploidy classes ≥16n. AHR knockdown also resulted in increased DNA synthesis of lower ploidy cells, without impacting apoptosis. Together, these data support a role for AHR in Mk polyploidization and in vivo platelet function, and warrant further detailed investigations. PMID:21226706

  6. DDE and PCB 153 independently induce aryl hydrocarbon receptor (AhR) expression in peripheral blood mononuclear cells.

    PubMed

    Gaspar-Ramírez, Octavio; Pérez-Vázquez, Francisco J; Salgado-Bustamante, Mariana; González-Amaro, Roberto; Hernandez-Castro, Berenice; Pérez-Maldonado, Ivan N

    2015-01-01

    Recent studies have demonstrated that compounds inducing pro-inflammatory cytokines enhance AhR expression. The aim of this study was 2-fold: (1) to determine if two pro-inflammatory compounds, dichlorodiphenyldichloroethylene (DDE) and 2,2',4,4',5,5'-hexa-chlorobiphenyl (PCB 153), independently affect AhR gene expression in peripheral blood mononuclear cells (PBMC); and (2) if affected, to determine whether the mechanism involved was due to AhR activation or to a pro-inflammatory effect of the chemicals. PBMC isolated from healthy individuals were incubated in the presence of DDE (10 µg/ml) and PCB 153 (20 ng/ml) over time and AhR and CYP1A1 expression was assessed with a real-time PCR technique. The results indicated there was over-expression of the AhR mRNA in PBMC when the cells were treated with DDE and PCB 153. No changes in expression levels of CYP1A1 mRNA were found. Importantly, when the cells were exposed to DDE and PCB 153 in the presence of an antagonist of tumor necrosis factor (TNF)-α, the over-expression of AhR was abolished; as expected, the expression of CYP1A1 was unaffected. In conclusion, these studies demonstrated for the first time an increment of AhR expression "in vitro" in PBMC treated with two pro-inflammatory environmental pollutants, DDE and PCB153. Moreover, the over-expression of AhR was dependent of TNFα induced by DDE and PCB 153 and was independent of AhR activation.

  7. Aryl hydrocarbon receptor activation by cAMP vs. dioxin: Divergent signaling pathways

    PubMed Central

    Oesch-Bartlomowicz, Barbara; Huelster, Andrea; Wiss, Oliver; Antoniou-Lipfert, Patricia; Dietrich, Cornelia; Arand, Michael; Weiss, Carsten; Bockamp, Ernesto; Oesch, Franz

    2005-01-01

    Even before the first vertebrates appeared on our planet, the aryl hydrocarbon receptor (AHR) gene was present to carry out one or more critical life functions. The vertebrate AHR then evolved to take on functions of detecting and responding to certain classes of environmental toxicants. These environmental pollutants include polycyclic aromatic hydrocarbons (e.g., benzo[a]pyrene), polyhalogenated hydrocarbons, dibenzofurans, and the most potent small-molecular-weight toxicant known, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD or dioxin). After binding of these ligands, the activated AHR translocates rapidly from the cytosol to the nucleus, where it forms a heterodimer with aryl hydrocarbon nuclear translocator, causing cellular responses that lead to toxicity, carcinogenesis, and teratogenesis. The nuclear form of the activated AHR/aryl hydrocarbon nuclear translocator complex is responsible for alterations in immune, endocrine, reproductive, developmental, cardiovascular, and central nervous system functions whose mechanisms remain poorly understood. Here, we show that the second messenger, cAMP (an endogenous mediator of hormones, neurotransmitters, and prostaglandins), activates the AHR, moving the receptor to the nucleus in some ways that are similar to and in other ways fundamentally different from AHR activation by dioxin. We suggest that this cAMP-mediated activation may reflect the true endogenous function of AHR; disruption of the cAMP-mediated activation by dioxin, binding chronically to the AHR for days, weeks, or months, might be pivotal in the mechanism of dioxin toxicity. Understanding this endogenous activation of the AHR by cAMP may help in developing methods to counteract the toxicity caused by numerous environmental and food-borne toxic chemicals that act via the AHR. PMID:15972329

  8. Aryl‐hydrocarbon receptor activity modulates prolactin expression in the pituitary

    SciTech Connect

    Moran, Tyler B.; Brannick, Katherine E.; Raetzman, Lori T.

    2012-11-15

    Pituitary tumors account for 15% of intracranial neoplasms, however the extent to which environmental toxicants contribute to the proliferation and hormone expression of pituitary cells is unknown. Aryl-hydrocarbon receptor (AhR) interacting protein (AIP) loss of function mutations cause somatotrope and lactotrope adenomas in humans. AIP sequesters AhR and inhibits its transcriptional function. Because of the link between AIP and pituitary tumors, we hypothesize that exposure to dioxins, potent exogenous ligands for AhR that are persistent in the environment, may predispose to pituitary dysfunction through activation of AhR. In the present study, we examined the effect of AhR activation on proliferation and endogenous pituitary hormone expression in the GH3 rat somatolactotrope tumor cell line and the effect of loss of AhR action in knockout mice. GH3 cells respond to nM doses of the reversible AhR agonist β-naphthoflavone with a robust induction of Cyp1a1. Although mRNA levels of the anti-proliferative signaling cytokine TGFbeta1 are suppressed upon β-naphthoflavone treatment, we did not observe an alteration in cell proliferation. AhR activation with β-naphthoflavone suppresses Ahr expression and impairs expression of prolactin (PRL), but not growth hormone (GH) mRNA in GH3 cells. In mice, loss of Ahr similarly leads to a reduction in Prl mRNA at P3, while Gh is unaffected. Additionally, there is a significant reduction in pituitary hormones Lhb and Fshb in the absence of Ahr. Overall, these results demonstrate that AhR is important for pituitary hormone expression and suggest that environmental dioxins can exert endocrine disrupting effects at the pituitary. -- Highlights: ► AhR signaling suppresses Prl mRNA expression. ► AhR signaling does not influence pituitary proliferation in culture. ► AhR is necessary for Prl, Lhb and Fshb expression at postnatal day 3.

  9. Protein kinase activators alter glial cholesterol esterification

    SciTech Connect

    Jeng, I.; Dills, C.; Klemm, N.; Wu, C.

    1986-05-01

    Similar to nonneural tissues, the activity of glial acyl-CoA cholesterol acyltransferase is controlled by a phosphorylation and dephosphorylation mechanism. Manipulation of cyclic AMP content did not alter the cellular cholesterol esterification, suggesting that cyclic AMP is not a bioregulator in this case. Therefore, the authors tested the effect of phorbol-12-myristate 13-acetate (PMA) on cellular cholesterol esterification to determine the involvement of protein kinase C. PMA has a potent effect on cellular cholesterol esterification. PMA depresses cholesterol esterification initially, but cells recover from inhibition and the result was higher cholesterol esterification, suggesting dual effects of protein kinase C. Studies of other phorbol analogues and other protein kinase C activators such as merezein indicate the involvement of protein kinase C. Oleoyl-acetyl glycerol duplicates the effect of PMA. This observation is consistent with a diacyl-glycerol-protein kinase-dependent reaction. Calcium ionophore A23187 was ineffective in promoting the effect of PMA. They concluded that a calcium-independent and protein C-dependent pathway regulated glial cholesterol esterification.

  10. Inhibition of constitutive aryl hydrocarbon receptor (AhR) signaling attenuates androgen independent signaling and growth in (C4-2) prostate cancer cells

    PubMed Central

    Tran, Cindy; Richmond, Oliver; Aaron, LaTayia; Powell, Joann B.

    2013-01-01

    The aryl hydrocarbon receptor is a member of the basic-helix-loop-helix family of transcription factors. AhR mediates the biochemical and toxic effects of a number of polyaromatic hydrocarbons such as 2,3,7,8,-tetrachloro-dibenzo-p-dioxin (TCDD). AhR is widely known for regulating the transcription of drug metabolizing enzymes involved in the xenobiotic metabolism of carcinogens and therapeutic agents, such as cytochrome P450-1B1 (CYP1B1). Additionally, AhR has also been reported to interact with multiple signaling pathways during prostate development. Here we investigate the effect of sustained AhR signaling on androgen receptor function in prostate cancer cells. Immunoblot analysis shows that AhR expression is increased in androgen independent (C4-2) prostate cancer cells when compared to androgen sensitive (LNCaP) cells. RT-PCR studies revealed constitutive AhR signaling in C4-2 cells without the ligand induced activation required in LNCaP cells. A reduction of AhR activity by short RNA mediated silencing in C4-2 cells reduced expression of both AhR and androgen responsive genes. The decrease in androgen responsive genes correlates to a decrease in phosphorylated androgen receptor and androgen receptor expression in the nucleus. Furthermore, the forced decrease in AhR expression resulted in a 50% decline in the growth rate of C4-2 cells. These data indicates that AhR is required to maintain hormone independent signaling and growth by the androgen receptor in C4-2 cells. Collectively, these data provide evidence of a direct role for AhR in androgen independent signaling and provides insight into the molecular mechanisms responsible for sustained androgen receptor signaling in hormone refractory prostate cancer. PMID:23266674

  11. The AhR is involved in the regulation of LoVo cell proliferation through cell cycle-associated proteins.

    PubMed

    Yin, Jiuheng; Sheng, Baifa; Han, Bin; Pu, Aimin; Yang, Kunqiu; Li, Ping; Wang, Qimeng; Xiao, Weidong; Yang, Hua

    2016-05-01

    Some ingredients in foods can activate the aryl hydrocarbon receptor (AhR) and arrest cell proliferation. In this study, we hypothesized that 6-formylindolo [3, 2-b] carbazole (FICZ) arrests the cell cycle in LoVo cells (a colon cancer line) through the AhR. The AhR agonist FICZ and the AhR antagonist CH223191 were used to treat LoVo cells. Real-time PCR and Western blot analyses were performed to detect the expression of the AhR, CYP1A1, CDK4, cyclinD1, cyclin E, CDK2, P27, and pRb. The distribution and activation of the AhR were detected with immunofluorescence. A 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay and flow cytometric analysis were performed to measure cell viability, cell cycle stage, and apoptosis. Our results show that FICZ inhibited LoVo cell proliferation by inducing G1 cell cycle arrest but had no effect on epithelial apoptosis. Further analysis found that FICZ downregulated cyclinD1 and upregulated p27 expression to arrest Rb phosphorylation. The downregulation of cyclinD1 and upregulation of p27 were abolished by co-treatment with CH223191. We conclude that the AhR, when activated by FICZ (an endogenous AhR ligand), can arrest the cell cycle and block LoVo cell proliferation.

  12. Inhibition of AHR transcription by NF1C is affected by a single-nucleotide polymorphism, and is involved in suppression of human uterine endometrial cancer.

    PubMed

    Li, D; Takao, T; Tsunematsu, R; Morokuma, S; Fukushima, K; Kobayashi, H; Saito, T; Furue, M; Wake, N; Asanoma, K

    2013-10-10

    Involvement of the aryl hydrocarbon receptor (AHR) in carcinogenesis has been suggested in many studies. Upregulation of AHR has been reported in some cancer species, and an association between single-nucleotide polymorphisms (SNPs) of AHR and cancer risk or cancer development has also been reported. This evidence suggests the involvement of some specific SNPs in AHR transcriptional regulation in the process of carcinogenesis or cancer development, but there have been no studies to elucidate the mechanism involved. In this study, we identified the transcription factor Nuclear Factor 1-C (NF1C) as a candidate to regulate AHR transcription in a polymorphism-dependent manner. SNP rs10249788 was included in a consensus binding site for NF1C. Our results suggested that NF1C preferred the C allele to the T allele at rs10249788 for binding. Forced expression of NF1C suppressed the activity of the AHR promoter with C at rs10249788 stronger than that with T. Moreover, expression analysis of human uterine endometrial cancer (HEC) specimens showed greater upregulation of AHR and downregulation of NF1C than those of normal endometrium specimens. Sequence analysis showed HEC patients at advanced stages tended to possess T/T alleles more frequently than healthy women. We also demonstrated that NF1C suppressed proliferation, motility and invasion of HEC cells. This function was at least partially mediated by AHR. This study is the first to report that a polymorphism on the AHR regulatory region affected transcriptional regulation of the AHR gene in vitro. Because NF1C is a tumor suppressor, our new insights into AHR deregulation and its polymorphisms could reveal novel mechanisms of genetic susceptibility to cancer.

  13. TOXICITY OF AHR AGONISTS TO FISH EARLY LIFE STAGES

    EPA Science Inventory

    Fish early life stages are exceptionally sensitive to the lethal toxicity of chemicals that act as arylhydrocarbon receptor (AhR) agonists. Toxicity characterizations based on 2,3,7,8-tetrachlorodibenzo-p-dioxin, generally the most potent AhR agonist, support the toxicity equiva...

  14. Functionality of aryl hydrocarbon receptors (AhR1 and AhR2) of white sturgeon (Acipenser transmontanus) and implications for the risk assessment of dioxin-like compounds.

    PubMed

    Doering, Jon A; Farmahin, Reza; Wiseman, Steve; Kennedy, Sean W; Giesy, John P; Hecker, Markus

    2014-07-15

    Worldwide, populations of sturgeons are endangered, and it is hypothesized that anthropogenic chemicals, including dioxin-like compounds (DLCs), might be contributing to the observed declines in populations. DLCs elicit their toxic action through activation of the aryl hydrocarbon receptor (AhR), which is believed to regulate most, if not all, adverse effects associated with exposure to these chemicals. Currently, risk assessment of DLCs in fishes uses toxic equivalency factors (TEFs) developed for the World Health Organization (WHO) that are based on studies of embryo-lethality with salmonids. However, there is a lack of knowledge of the sensitivity of sturgeons to DLCs, and it is uncertain whether TEFs developed by the WHO are protective of these fishes. Sturgeons are evolutionarily distinct from salmonids, and the AhRs of sturgeons differ from those of salmonids. Therefore, this study investigated the sensitivity of white sturgeon (Acipenser transmontanus) to DLCs in vitro via the use of luciferase reporter gene assays using COS-7 cells transfected with AhR1 or AhR2 of white sturgeon. Specifically, activation and relative potencies (RePs) of 2,3,7,8-tetrachloro-dibenzo-p-dioxin (TCDD), 2,3,4,7,8-pentachloro-dibenzofuran, 2,3,7,8-tetrachloro-dibenzofuran, 3,3',4,4',5-pentachlorobiphenyl, 3,3',4,4'-tetrachlorobiphenyl, and 2,3,3',4,4'-pentachlorobiphenyl were determined for each AhR. It was demonstrated that white sturgeon expresses AhR1s and AhR2s that are both activated by DLCs with EC50 values for 2,3,7,8-TCDD that are lower than those of any other AhR of vertebrates tested to date. Both AhRs of white sturgeon had RePs for polychlorinated dibenzofurans more similar to TEFs for birds, while RePs for polychlorinated biphenyls were most similar to TEFs for fishes. Measured concentrations of select DLCs in tissues of white sturgeon from British Columbia, Canada, were used to calculate toxic equivalents (TEQs) by use of TEFs for fishes used by the WHO and TCDD

  15. Metabolic control of type 1 regulatory (Tr1) cell differentiation by AHR and HIF1-α

    PubMed Central

    Mascanfroni, Ivan D.; Takenaka, Maisa C.; Yeste, Ada; Patel, Bonny; Wu, Yan; Kenison, Jessica E.; Siddiqui, Shafiuddin; Basso, Alexandre S.; Otterbein, Leo E.; Pardoll, Drew M.; Pan, Fan; Priel, Avner; Clish, Clary B.; Robson, Simon C.; Quintana, Francisco J.

    2015-01-01

    Our understanding of the pathways that regulate lymphocyte metabolism, as well as the effects of metabolism and its products on the immune response, is still limited. We report that a metabolic program controlled by the transcription factors hypoxia inducible factor-1α (HIF1-α) and aryl hydrocarbon receptor (AHR) supports the differentiation of type 1 regulatory (Tr1) cells. HIF1-α controls the early metabolic reprograming of Tr1 cells. At later time points, AHR promotes HIF1-α degradation and takes control of Tr1 cell metabolism. Extracellular adenosine triphosphate (eATP) and hypoxia, linked to inflammation, trigger AHR inactivation by HIF1-α and inhibit Tr1 cell differentiation. Conversely, CD39 promotes Tr1 cell differentiation by depleting eATP. CD39 also contributes to Tr1 suppressive activity by generating adenosine in cooperation with CD73 expressed by responder T cells and antigen presenting cells. These results suggest that HIF1-α and AHR integrate immunological, metabolic and environmental signals to regulate the immune response. PMID:26005855

  16. Autoradiographic localization of aromatic hydrocarbon receptor (AHR) in rhesus monkey ovary.

    PubMed

    Baldridge, Monika G; Hutz, Reinhold J

    2007-06-01

    2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is the most toxic congener of a large class of manmade pollutants that persist in the environment. TCDD exerts its toxic effects, in part, by binding to its receptor known as the aromatic hydrocarbon receptor (AHR). TCDD is estrogen modulatory and in some systems its receptor associates directly with estrogen receptors via co-activator molecules. TCDD inhibits steroid synthesis in human ovarian granulosa cells and AHR is found in these cells. We have previously shown that AHR is found in whole rhesus monkey ovary, but have yet to establish its location. In the present study, we set out to show that radiolabeled TCDD binds to monkey ovarian follicles and that this binding is receptor mediated. Ovaries from Macaca mulatta were sectioned on a cryostat at 10 micro m; and sections were incubated with either control vehicle, (3)H-TCDD, or (3)H-TCDD plus alpha-naphthoflavone (ANF), a known receptor-blocking agent. Here, we show for the first time specific binding of TCDD to the granulosa cells of antral follicles and other regions of the rhesus monkey ovary. Our data indicate a 60-fold increase in binding with (3)H-TCDD over that of control, and that this binding is reduced to the levels seen in controls with the addition of the competitive antagonist ANF. These findings support the hypothesis that TCDD directly affects primate ovarian function via the AHR.

  17. Intersection of AHR and Wnt Signaling in Development, Health, and Disease

    PubMed Central

    Schneider, Andrew J.; Branam, Amanda M.; Peterson, Richard E.

    2014-01-01

    The AHR (aryl hydrocarbon receptor) and Wnt (wingless-related MMTV integration site) signaling pathways have been conserved throughout evolution. Appropriately regulated signaling through each pathway is necessary for normal development and health, while dysregulation can lead to developmental defects and disease. Though both pathways have been vigorously studied, there is relatively little research exploring the possibility of crosstalk between these pathways. In this review, we provide a brief background on (1) the roles of both AHR and Wnt signaling in development and disease, and (2) the molecular mechanisms that characterize activation of each pathway. We also discuss the need for careful and complete experimental evaluation of each pathway and describe existing research that explores the intersection of AHR and Wnt signaling. Lastly, to illustrate in detail the intersection of AHR and Wnt signaling, we summarize our recent findings which show that 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-induced disruption of Wnt signaling impairs fetal prostate development. PMID:25286307

  18. Genome Editing of the CYP1A1 Locus in iPSCs as a Platform to Map AHR Expression throughout Human Development

    PubMed Central

    Smith, Brenden W.; Stanford, Elizabeth A.; Sherr, David H.; Murphy, George J.

    2016-01-01

    The aryl hydrocarbon receptor (AHR) is a ligand activated transcription factor that increases the expression of detoxifying enzymes upon ligand stimulation. Recent studies now suggest that novel endogenous roles of the AHR exist throughout development. In an effort to create an optimized model system for the study of AHR signaling in several cellular lineages, we have employed a CRISPR/CAS9 genome editing strategy in induced pluripotent stem cells (iPSCs) to incorporate a reporter cassette at the transcription start site of one of its canonical targets, cytochrome P450 1A1 (CYP1A1). This cell line faithfully reports on CYP1A1 expression, with luciferase levels as its functional readout, when treated with an endogenous AHR ligand (FICZ) at escalating doses. iPSC-derived fibroblast-like cells respond to acute exposure to environmental and endogenous AHR ligands, and iPSC-derived hepatocytes increase CYP1A1 in a similar manner to primary hepatocytes. This cell line is an important innovation that can be used to map AHR activity in discrete cellular subsets throughout developmental ontogeny. As further endogenous ligands are proposed, this line can be used to screen for safety and efficacy and can report on the ability of small molecules to regulate critical cellular processes by modulating the activity of the AHR. PMID:27148368

  19. AHR2 morpholino knockdown reduces the toxicity of total particulate matter to zebrafish embryos.

    PubMed

    Massarsky, Andrey; Bone, Audrey J; Dong, Wu; Hinton, David E; Prasad, G L; Di Giulio, Richard T

    2016-10-15

    The zebrafish embryo has been proposed as a 'bridge model' to study the effects of cigarette smoke on early development. Previous studies showed that exposure to total particulate matter (TPM) led to adverse effects in developing zebrafish, and suggested that the antioxidant and aryl hydrocarbon receptor (AHR) pathways play important roles. This study investigated the roles of these two pathways in mediating TPM toxicity. The study consisted of four experiments. In experiment I, zebrafish embryos were exposed from 6h post fertilization (hpf) until 96hpf to TPM0.5 and TPM1.0 (corresponding to 0.5 and 1.0μg/mL equi-nicotine units) in the presence or absence of an antioxidant (N-acetyl cysteine/NAC) or a pro-oxidant (buthionine sulfoximine/BSO). In experiment II, TPM exposures were performed in embryos that were microinjected with nuclear factor erythroid 2-related factor 2 (Nrf2), AHR2, cytochrome P450 1A (CYP1A), or CYP1B1 morpholinos, and deformities were assessed. In experiment III, embryos were exposed to TPM, and embryos/larvae were collected at 24, 48, 72, and 96hpf to assess several genes associated with the antioxidant and AHR pathways. Lastly, experiment IV assessed the activity and protein levels of CYP1A and CYP1B1 after exposure to TPM. We demonstrate that the incidence of TPM-induced deformities was generally not affected by NAC/BSO treatments or Nrf2 knockdown. In contrast, AHR2 knockdown reduced, while CYP1A or CYP1B1 knockdowns elevated the incidence of some deformities. Moreover, as shown by gene expression the AHR pathway, but not the antioxidant pathway, was induced in response to TPM exposure, providing further evidence for its importance in mediating TPM toxicity.

  20. AHR2 morpholino knockdown reduces the toxicity of total particulate matter to zebrafish embryos.

    PubMed

    Massarsky, Andrey; Bone, Audrey J; Dong, Wu; Hinton, David E; Prasad, G L; Di Giulio, Richard T

    2016-10-15

    The zebrafish embryo has been proposed as a 'bridge model' to study the effects of cigarette smoke on early development. Previous studies showed that exposure to total particulate matter (TPM) led to adverse effects in developing zebrafish, and suggested that the antioxidant and aryl hydrocarbon receptor (AHR) pathways play important roles. This study investigated the roles of these two pathways in mediating TPM toxicity. The study consisted of four experiments. In experiment I, zebrafish embryos were exposed from 6h post fertilization (hpf) until 96hpf to TPM0.5 and TPM1.0 (corresponding to 0.5 and 1.0μg/mL equi-nicotine units) in the presence or absence of an antioxidant (N-acetyl cysteine/NAC) or a pro-oxidant (buthionine sulfoximine/BSO). In experiment II, TPM exposures were performed in embryos that were microinjected with nuclear factor erythroid 2-related factor 2 (Nrf2), AHR2, cytochrome P450 1A (CYP1A), or CYP1B1 morpholinos, and deformities were assessed. In experiment III, embryos were exposed to TPM, and embryos/larvae were collected at 24, 48, 72, and 96hpf to assess several genes associated with the antioxidant and AHR pathways. Lastly, experiment IV assessed the activity and protein levels of CYP1A and CYP1B1 after exposure to TPM. We demonstrate that the incidence of TPM-induced deformities was generally not affected by NAC/BSO treatments or Nrf2 knockdown. In contrast, AHR2 knockdown reduced, while CYP1A or CYP1B1 knockdowns elevated the incidence of some deformities. Moreover, as shown by gene expression the AHR pathway, but not the antioxidant pathway, was induced in response to TPM exposure, providing further evidence for its importance in mediating TPM toxicity. PMID:27576004

  1. Constitutive IDO expression in human cancer is sustained by an autocrine signaling loop involving IL-6, STAT3 and the AHR.

    PubMed

    Litzenburger, Ulrike M; Opitz, Christiane A; Sahm, Felix; Rauschenbach, Katharina J; Trump, Saskia; Winter, Marcus; Ott, Martina; Ochs, Katharina; Lutz, Christian; Liu, Xiangdong; Anastasov, Natasa; Lehmann, Irina; Höfer, Thomas; von Deimling, Andreas; Wick, Wolfgang; Platten, Michael

    2014-02-28

    Indoleamine-2,3-dioxygenase (IDO) inhibitors have entered clinical trials based on their ability to restore anti-tumor immunity in preclinical studies. However, the mechanisms leading to constitutive expression of IDO in human tumors are largely unknown. Here we analyzed the pathways mediating constitutive IDO expression in human cancer. IDO-positive tumor cells and tissues showed basal phosphorylation and acetylation of STAT3 as evidenced by western blotting and immunoprecipitation. Inhibition of IL-6 or STAT3 using siRNA and/or pharmacological inhibitors reduced IDO mRNA and protein expression as well as kynurenine formation. In turn, IDO enzymatic activity activated the AHR as shown by the induction of AHR target genes. IDO-mediated AHR activation induced IL-6 expression, while inhibition or knockdown of the AHR reduced IL-6 expression. IDO activity thus sustains its own expression via an autocrine AHR-IL-6-STAT3 signaling loop. Inhibition of the AHR-IL-6-STAT3 signaling loop restored T-cell proliferation in mixed leukocyte reactions performed in the presence of IDO-expressing human cancer cells. Identification of the IDO-AHR-IL-6-STAT3 signaling loop maintaining IDO expression in human cancers reveals novel therapeutic targets for the inhibition of this core pathway promoting immunosuppression of human cancers. The relevance of the IDO-AHR-IL-6-STAT3 transcriptional circuit is underscored by the finding that high expression of its members IDO, STAT3 and the AHR target gene CYP1B1 is associated with reduced relapse-free survival in lung cancer patients.

  2. Selective Aryl Hydrocarbon Receptor Modulator 3,3'-Diindolylmethane Impairs AhR and ARNT Signaling and Protects Mouse Neuronal Cells Against Hypoxia.

    PubMed

    Rzemieniec, J; Litwa, E; Wnuk, A; Lason, W; Krzeptowski, W; Kajta, M

    2016-10-01

    The neuroprotective potential of 3,3'-diindolylmethane (DIM), which is a selective aryl hydrocarbon receptor modulator, has recently been shown in cellular and animal models of Parkinson's disease and lipopolysaccharide-induced inflammation. However, there are no data concerning the protective capacity and mechanisms of DIM action in neuronal cells exposed to hypoxia. The aim of the present study was to investigate the neuroprotective potential of DIM against the hypoxia-induced damage in mouse hippocampal cells in primary cultures, with a particular focus on DIM interactions with the aryl hydrocarbon receptor (AhR), its nuclear translocator ARNT, and estrogen receptor β (ERβ). In the present study, 18 h of hypoxia induced apoptotic processes, in terms of the mitochondrial membrane potential, activation of caspase-3, and fragmentation of cell nuclei. These effects were accompanied by substantial lactate dehydrogenase release and neuronal cell death. The results of the present study demonstrated strong neuroprotective and anti-apoptotic actions of DIM in hippocampal cells exposed to hypoxia. In addition, DIM decreased the Ahr and Arnt mRNA expression and stimulated Erβ mRNA expression level. DIM-induced mRNA alterations were mirrored by changes in protein levels, except for ERβ, as detected by ELISA, Western blotting, and immunofluorescence labeling. We also demonstrated that DIM decreased the expression of AhR-regulated CYP1A1. Using specific siRNAs, we provided evidence that impairment of AhR and ARNT, but not ERβ plays a key role in the neuroprotective action of DIM against hypoxia-induced cell damage. This study may have implication for identifying new agents that could protect neurons against hypoxia by targeting AhR/ARNT signaling. PMID:26476840

  3. Simulator for SUPO, a Benchmark Aqueous Homogeneous Reactor (AHR)

    SciTech Connect

    Klein, Steven Karl; Determan, John C.

    2015-10-14

    A simulator has been developed for SUPO (Super Power) an aqueous homogeneous reactor (AHR) that operated at Los Alamos National Laboratory (LANL) from 1951 to 1974. During that period SUPO accumulated approximately 600,000 kWh of operation. It is considered the benchmark for steady-state operation of an AHR. The SUPO simulator was developed using the process that resulted in a simulator for an accelerator-driven subcritical system, which has been previously reported.

  4. Kynurenine, by activating aryl hydrocarbon receptor, decreases erythropoietin and increases hepcidin production in HepG2 cells: A new mechanism for anemia of inflammation.

    PubMed

    Eleftheriadis, Theodoros; Pissas, Georgios; Antoniadi, Georgia; Liakopoulos, Vassilios; Stefanidis, Ioannis

    2016-01-01

    It is known that inadequate erythropoietin (EPO) production contributes to the pathogenesis of anemia of inflammation, although the exact molecular mechanism is unknown. Aryl hydrocarbon receptor (AhR) may compete with hypoxia-inducible factor 2α (HIF-2α), the master regulator of EPO production, for binding with HIF-1β. The effect of kynurenine, an endogenous AhR activator that increases in inflammation, on EPO and hepcidin production was evaluated. HepG2 cells were treated with the hypoxia mimetic CoCl2, kynurenine, the AhR inhibitor CH223191, and combinations of these. EPO and hepcidin production was measured with enzyme-linked immunosorbent assay. HIF-2α and CYP1A1 levels, a transcriptional target of AhR, were assessed by Western blotting. CoCl2 increased EPO production and decreased hepcidin and CYP1A1. Kynurenine exerted the opposite effects. Wherever CH223191 was added, the inhibitor overcorrected kynurenine-induced alterations in both the presence and the absence of CoCl2. Also, treatment with CH223191 alone increased EPO and decreased hepcidin, indicating that there is a degree of constitutive AhR activation, possibly by other endogenous AhR activators. In conclusion, kynurenine, by competing with HIF-2α, may contribute to anemia of inflammation by decreasing EPO and increasing hepcidin production. The fact that inactivation of AhR alone induces EPO makes this transcription factor a potential therapeutic target in situations that require increased EPO.

  5. Inhibition of cytochrome P4501-dependent clearance of the endogenous agonist FICZ as a mechanism for activation of the aryl hydrocarbon receptor

    PubMed Central

    Wincent, Emma; Bengtsson, Johanna; Bardbori, Afshin Mohammadi; Alsberg, Tomas; Luecke, Sandra; Rannug, Ulf; Rannug, Agneta

    2012-01-01

    Altered systemic levels of 6-formylindolo[3,2-b]carbazole (FICZ), an enigmatic endogenous ligand for the aryl hydrocarbon receptor (AHR), may explain adverse physiological responses evoked by small natural and anthropogenic molecules as well as by oxidative stress and light. We demonstrate here that several different chemical compounds can inhibit the metabolism of FICZ, thereby disrupting the autoregulatory feedback control of cytochrome P4501 systems and other proteins whose expression is regulated by AHR. FICZ is both the most tightly bound endogenous agonist for the AHR and an ideal substrate for cytochrome CYP1A1/1A2 and 1B1, thereby also participating in an autoregulatory loop that keeps its own steady-state concentration low. At very low concentrations FICZ influences circadian rhythms, responses to UV light, homeostasis associated with pro- and anti-inflammatory processes, and genomic stability. Here, we demonstrate that, if its metabolic clearance is compromised, femtomolar background levels of this compound in cell-culture medium are sufficient to up-regulate CYP1A1 mRNA and enzyme activity. The oxidants UVB irradiation and hydrogen peroxide and the model AHR antagonist 3′-methoxy-4′-nitroflavone all inhibited induction of CYP1A1 enzyme activity by FICZ or 2,3,7,8-tetrachlorodibenzo-p-dioxin, thereby subsequently elevating intracellular levels of FICZ and activating AHR. Taken together, these findings support an indirect mechanism of AHR activation, indicating that AHR activation by molecules with low affinity actually may reflect inhibition of FICZ metabolism and raising questions about the reported promiscuity of the AHR. Accordingly, we propose that prolonged induction of AHR activity through inhibition of CYP1 disturbs feedback regulation of FICZ levels, with potential detrimental consequences. PMID:22392998

  6. Does mental exertion alter maximal muscle activation?

    PubMed Central

    Rozand, Vianney; Pageaux, Benjamin; Marcora, Samuele M.; Papaxanthis, Charalambos; Lepers, Romuald

    2014-01-01

    Mental exertion is known to impair endurance performance, but its effects on neuromuscular function remain unclear. The purpose of this study was to test the hypothesis that mental exertion reduces torque and muscle activation during intermittent maximal voluntary contractions of the knee extensors. Ten subjects performed in a randomized order three separate mental exertion conditions lasting 27 min each: (i) high mental exertion (incongruent Stroop task), (ii) moderate mental exertion (congruent Stroop task), (iii) low mental exertion (watching a movie). In each condition, mental exertion was combined with 10 intermittent maximal voluntary contractions of the knee extensor muscles (one maximal voluntary contraction every 3 min). Neuromuscular function was assessed using electrical nerve stimulation. Maximal voluntary torque, maximal muscle activation and other neuromuscular parameters were similar across mental exertion conditions and did not change over time. These findings suggest that mental exertion does not affect neuromuscular function during intermittent maximal voluntary contractions of the knee extensors. PMID:25309404

  7. The Q-rich/PST domain of the AHR regulates both ligand-induced nuclear transport and nucleocytoplasmic shuttling

    PubMed Central

    Tkachenko, Anna; Henkler, Frank; Brinkmann, Joep; Sowada, Juliane; Genkinger, Doris; Kern, Christian; Tralau, Tewes; Luch, Andreas

    2016-01-01

    The aryl hydrocarbon receptor (AHR) shuttles continuously between cytoplasm and nucleus, unless ligand-binding triggers association with the AHR nuclear translocator (ARNT) and subsequent binding to cognate DNA motifs. We have now identified Val 647 as mandatory residue for export from the nucleus and AHR-function. This residue prevents inactivation of the receptor as a consequence of nuclear sequestration via constitutive import. Concomitantly mutants lacking this residue are exclusively localised in the nucleus. Although ligands accelerate nuclear import transiently, stable nuclear transition depends on a motif adjacent to Val 647 that comprises residues 650–661. Together, this defined region within the Q-rich domain regulates intracellular trafficking of the AHR in context of both nucleocytoplasmic shuttling and receptor activation. Nuclear export therefore depends on the previously characterised N-terminal NES and the newly identified motif that includes V647. Nucleocytoplasmic distribution of full-length human AHR is further affected by a section of the PST domain that shows sequence similarities with nuclear export signals. In concert, these motifs maintain a predominant cytoplasmic compartmentalisation, receptive for ligand binding. PMID:27535013

  8. The Q-rich/PST domain of the AHR regulates both ligand-induced nuclear transport and nucleocytoplasmic shuttling.

    PubMed

    Tkachenko, Anna; Henkler, Frank; Brinkmann, Joep; Sowada, Juliane; Genkinger, Doris; Kern, Christian; Tralau, Tewes; Luch, Andreas

    2016-01-01

    The aryl hydrocarbon receptor (AHR) shuttles continuously between cytoplasm and nucleus, unless ligand-binding triggers association with the AHR nuclear translocator (ARNT) and subsequent binding to cognate DNA motifs. We have now identified Val 647 as mandatory residue for export from the nucleus and AHR-function. This residue prevents inactivation of the receptor as a consequence of nuclear sequestration via constitutive import. Concomitantly mutants lacking this residue are exclusively localised in the nucleus. Although ligands accelerate nuclear import transiently, stable nuclear transition depends on a motif adjacent to Val 647 that comprises residues 650-661. Together, this defined region within the Q-rich domain regulates intracellular trafficking of the AHR in context of both nucleocytoplasmic shuttling and receptor activation. Nuclear export therefore depends on the previously characterised N-terminal NES and the newly identified motif that includes V647. Nucleocytoplasmic distribution of full-length human AHR is further affected by a section of the PST domain that shows sequence similarities with nuclear export signals. In concert, these motifs maintain a predominant cytoplasmic compartmentalisation, receptive for ligand binding. PMID:27535013

  9. Mono-Substituted Isopropylated Triaryl Phosphate, a Major Component of Firemaster 550, is an AHR Agonist that Exhibits AHR-Independent Cardiotoxicity in Zebrafish

    PubMed Central

    Gerlach, Cory V.; Das, Siba R.; Volz, David C.; Bisson, William H.; Kolluri, Siva K.; Tanguay, Robert L.

    2014-01-01

    Firemaster 550 (FM550) is an additive flame retardant mixture used within polyurethane foam and is increasingly found in house dust and the environment due to leaching. Despite the widespread use of FM550, very few studies have investigated the potential toxicity of its ingredients during early vertebrate development. In the current study, we sought to specifically investigate mono-substituted isopropylated triaryl phosphate (mITP), a component comprising approximately 32% of FM550, which has been shown to cause cardiotoxicity during zebrafish embryogenesis. Previous research showed that developmental defects are rescued using an aryl hydrocarbon receptor (AHR) antagonist (CH223191), suggesting that mITP-induced toxicity was AHR-dependent. As zebrafish have three known AHR isoforms, we used a functional AHR2 knockout line along with AHR1A-and AHR1B-specific morpholinos to determine which AHR isoform, if any, mediates mITP-induced cardiotoxicity. As in silico structural homology modeling predicted that mITP may bind favorably to both AHR2 and AHR1B isoforms, we evaluated AHR involvement in vivo by measuring CYP1A mRNA and protein expression following exposure to mITP in the presence or absence of CH223191 or AHR-specific morpholinos. Based on these studies, we found that mITP interacts with both AHR2 and AHR1B isoforms to induce CYP1A expression. However, while CH223191 blocked mITP-induced CYP1A induction and cardiotoxicity, knockdown of all three AHR isoforms failed to block mITP-induced cardiotoxicity in the absence of detectable CYP1A induction. Overall, these results suggest that, while mITP is an AHR agonist, mITP causes AHR-independent cardiotoxicity through a pathway that is also antagonized by CH223191. PMID:24865613

  10. Ultraviolet light converts propranolol, a nonselective β-blocker and potential lupus-inducing drug, into a proinflammatory AhR ligand.

    PubMed

    Dorgham, Karim; Amoura, Zahir; Parizot, Christophe; Arnaud, Laurent; Frances, Camille; Pionneau, Cédric; Devilliers, Hervé; Pinto, Sandra; Zoorob, Rima; Miyara, Makoto; Larsen, Martin; Yssel, Hans; Gorochov, Guy; Mathian, Alexis

    2015-11-01

    UV light and some medications are known to trigger lupus erythematosus (LE). A common mechanism underlying the immunopathologic effect, resulting from exposure to these two seemingly unrelated factors, remains unknown. The aryl hydrocarbon receptor (AhR) plays a key role in the regulation of IL-22 production in humans and can be activated by both xenobiotics and naturally occurring photoproducts. A significant expansion of Th17 and Th22 cells was observed in the peripheral blood of active systemic LE (SLE) patients, compared to inactive patients and controls. We also show that propranolol, a potential lupus-inducing drug, induced stronger AhR activation in PBMCs of SLE patients than in those of controls. AhR agonist activity of propranolol was enhanced by UV light exposure. MS analysis of irradiated propranolol revealed the generation of a proinflammatory photoproduct. This compound behaves like the prototypic AhR ligand 6-formylindolo[3,2-b]carbazole, a cutaneous UV light-induced tryptophan metabolite, both promoting IL-22, IL-8, and CCL2 secretion by T-cells and macrophages. Finally, LE patients exhibit signs of cutaneous AhR activation that correlate with lesional expression of the same proinflammatory cytokines, suggesting a role for photometabolites in the induction of skin inflammation. The AhR might therefore represent a target for therapeutic intervention in LE. PMID:26354876

  11. Ultraviolet light converts propranolol, a nonselective β-blocker and potential lupus-inducing drug, into a proinflammatory AhR ligand.

    PubMed

    Dorgham, Karim; Amoura, Zahir; Parizot, Christophe; Arnaud, Laurent; Frances, Camille; Pionneau, Cédric; Devilliers, Hervé; Pinto, Sandra; Zoorob, Rima; Miyara, Makoto; Larsen, Martin; Yssel, Hans; Gorochov, Guy; Mathian, Alexis

    2015-11-01

    UV light and some medications are known to trigger lupus erythematosus (LE). A common mechanism underlying the immunopathologic effect, resulting from exposure to these two seemingly unrelated factors, remains unknown. The aryl hydrocarbon receptor (AhR) plays a key role in the regulation of IL-22 production in humans and can be activated by both xenobiotics and naturally occurring photoproducts. A significant expansion of Th17 and Th22 cells was observed in the peripheral blood of active systemic LE (SLE) patients, compared to inactive patients and controls. We also show that propranolol, a potential lupus-inducing drug, induced stronger AhR activation in PBMCs of SLE patients than in those of controls. AhR agonist activity of propranolol was enhanced by UV light exposure. MS analysis of irradiated propranolol revealed the generation of a proinflammatory photoproduct. This compound behaves like the prototypic AhR ligand 6-formylindolo[3,2-b]carbazole, a cutaneous UV light-induced tryptophan metabolite, both promoting IL-22, IL-8, and CCL2 secretion by T-cells and macrophages. Finally, LE patients exhibit signs of cutaneous AhR activation that correlate with lesional expression of the same proinflammatory cytokines, suggesting a role for photometabolites in the induction of skin inflammation. The AhR might therefore represent a target for therapeutic intervention in LE.

  12. Altered myoelectric activity in the experimental blind loop syndrome.

    PubMed

    Justus, P G; Fernandez, A; Martin, J L; King, C E; Toskes, P P; Mathias, J R

    1983-09-01

    Nutrient malabsorption and diarrhea are characteristic of the blind loop syndrome. Alterations in motility have been implicated as a cause of bacterial overgrowth, but the possibility that altered motility may result from alterations in the flora has not been explored. The purpose of this study was to characterize the myoelectric activity of the small intestine in the blind loop rat model. Eight groups of rats were studied: rats with self-filling blind loops, which develop bacterial overgrowth; rats with self-emptying blind loops, which are surgical controls that do not develop overgrowth; unoperated litter mates; rats with self-filling blind loops and unoperated controls treated with chloramphenicol, 200 mg/d i.p.; rats with surgically removed self-filling blind loops; operated control rats; and gnotobiotic rats with self-filling blind loops. In the untreated rats with self-filling blind loops, there was altered myoelectric activity characterized by an increased percentage of slow waves occupied by action potentials and by organized activity similar to the migrating action potential complex. Migrating action potential complex activity and percentage of slow waves occupied by action potentials were significantly decreased with chloramphenicol therapy; that decrease correlated with a decrease in aerobes and anaerobes. Migrating action potential complex activity was abolished in rats with surgically removed self-filling blind loops; they also showed a significant decrease in percentage of slow waves occupied by action potentials. Gnotobiotic rats with self-filling blind loops showed no alteration in myoelectric activity. These data indicate: (a) bacterial overgrowth is associated with a significant increase in percentage of slow waves occupied by action potentials and migrating action potential complex activity; (b) chloramphenicol significantly reduced both percentage of slow waves occupied by action potentials and migrating action potential complex activity; and (c

  13. Aryl hydrocarbon receptor activation in lactotropes and gonadotropes interferes with estradiol-dependent and -independent preprolactin, glycoprotein alpha and luteinizing hormone beta gene expression.

    PubMed

    Cao, Jinyan; Patisaul, Heather B; Petersen, Sandra L

    2011-02-20

    Arylhydrocarbon receptor (Ahr) activation by 2,3,7,8-tetrachlordibenzo-p-dioxin (TCDD) interferes with female reproductive functions, but there is little information on the specific targets of TCDD in the hypothalamic-pituitary-gonadal (HPG) axis. In these studies, we found that TCDD upregulated known AhR target genes, cytochrome p450 1a1 (Cyp1a1), Cyp1a2 and Cyp1b1 in the rat pituitary gland. Moreover, 75% of pituitary lactotropes and 45% of gonadotropes contained Ahr mRNA, and most Ahr-containing cells were estrogen receptor 1 (Esr1)-positive. TCDD abrogated estradiol (E(2))-induced prolactin (Prl) expression in vivo and in vitro; conversely, E(2) blocked TCDD upregulation of luteinizing hormone beta (Lhb) and glycoprotein hormone alpha polypeptide (Cga) expression. TCDD had no effect on levels of Ahr mRNA, but upregulated Esr1 mRNA. E(2) independently repressed Ahr and Esr1 expression and blocked TCDD upregulation of Esr1. Thus, complex interactions between Ahr and Esr alter Prl and luteinizing hormone (LH) synthesis by direct actions in lactotropes and gonadotropes. These findings provide important insights into how TCDD disrupts female reproductive functions.

  14. Aryl Hydrocarbon Receptor Activation in Lactotropes and Gonadotropes Interferes with Estradiol-Dependent and -Independent Preprolactin, Glycoprotein Alpha and Luteinizing Hormone Beta Gene Expression

    PubMed Central

    Cao, JinYan; Patisaul, Heather B.; Petersen, Sandra L.

    2011-01-01

    Arylhydrocarbon receptor (Ahr) activation by 2,3,7,8-tetrachlordibenzo-p-dioxin (TCDD) interferes with female reproductive functions, but there is little information on the specific targets of TCDD in the hypothalamic-pituitary-gonadal (HPG) axis. In these studies, we found that TCDD upregulated known AhR target genes, cytochrome p450 1a1 (Cyp1a1), Cyp1a2 and Cyp1b1 in the rat pituitary gland. Moreover, 75% of pituitary lactotropes and 45% of gonadotropes contained Ahr mRNA, and most Ahr-containing cells were estrogen receptor 1 (Esr1)-positive. TCDD abrogated estradiol (E2)-induced prolactin (Prl) expression in vivo and in vitro; conversely, E2 blocked TCDD upregulation of luteinizing hormone beta (Lhb) and glycoprotein hormone alpha polypeptide (Cga) expression. TCDD had no effect on levels of Ahr mRNA, but upregulated Esr1 mRNA. E2 independently repressed Ahr and Esr1 expression and blocked TCDD upregulation of Esr1. Thus, complex interactions between Ahr and Esr alter Prl and luteinizing hormone (LH) synthesis by direct actions in lactotropes and gonadotropes. These findings provide important insights into how TCDD disrupts female reproductive functions. PMID:21187122

  15. Zebrafish Cardiotoxicity: The Effects of CYP1A Inhibition and AHR2 Knockdown Following Exposure to Weak Aryl Hydrocarbon Receptor Agonists

    PubMed Central

    Clark, Bryan William; Van Tiem Garner, Lindsey; Di Giulio, Richard Thomas

    2014-01-01

    The aryl hydrocarbon receptor (AHR) is a ligand-activated transcription factor that mediates many of the toxic effects of dioxin-like compounds (DLCs) and some polycyclic aromatic hydrocarbons (PAHs). Strong AHR agonists, such as certain polychlorinated biphenyls and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), cause severe cardiac teratogenesis in fish embryos. Moderately strong AHR agonists, such as benzo[a]pyrene and β-naphthoflavone, have been shown to cause similar cardiotoxic effects when coupled with a cytochrome P450 1A (CYP1A) inhibitor, such as fluoranthene (FL). We sought to determine if weak AHR agonists, when combined with a CYP1A inhibitor (FL) or CYP1A morpholino gene knockdown, are capable of causing cardiac deformities similar to moderately strong AHR agonists (Wassenberg and Di Giulio 2004; Wassenberg and Di Giulio 2004; Billiard, Timme-Laragy et al. 2006; Van Tiem and Di Giulio 2011). The weak AHR agonists included the following: carbaryl, phenanthrene, 2-methylindole, 3-methylindole, indigo, and indirubin. The results showed a complex pattern of cardiotoxic response to weak agonist inhibitor exposure and morpholino-knockdown. Danio rerio (zebrafish) embryos were first exposed to weak AHR agonists at equimolar concentrations. The agonists were assessed for their relative potency as inducers of CYP1 enzyme activity, measured by the ethoxyresorufin-o-deethylase (EROD) assay, and cardiac deformities. Carbaryl, 2-methylindole, and 3-methylindole induced the highest CYP1A activity in zebrafish. Experiments were then conducted to determine the individual cardiotoxicity of each compound. Next, zebrafish were co-exposed to each agonist (at concentrations below those determined to be cardiotoxic) and FL in combination to assess if CYP1A inhibition could induce cardiac deformities. Carbaryl, 2-methylindole, 3-methylindole, and phenanthrene significantly increased pericardial edema relative to controls when combined with FL. To further evaluate the

  16. Characterizing the role of endothelin-1 in the progression of cardiac hypertrophy in aryl hydrocarbon receptor (AhR) null mice

    SciTech Connect

    Lund, Amie K.; Goens, M. Beth; Nunez, Bethany A.; Walker, Mary K. . E-mail: mkwalker@unm.edu

    2006-04-15

    The aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor characterized to play a role in detection and adaptation to environmental stimuli. Genetic deletion of AhR results in hypertension, and cardiac hypertrophy and fibrosis, associated with elevated plasma angiotensin II (Ang II) and endothelin-1 (ET-1), thus AhR appears to contribute to cardiovascular homeostasis. In these studies, we tested the hypothesis that ET-1 mediates cardiovascular pathology in AhR null mice via ET{sub A} receptor activation. First, we determine the time courses of cardiac hypertrophy, and of plasma and tissue ET-1 expression in AhR wildtype and null mice. AhR null mice exhibited increases in heart-to-body weight ratio and age-related expression of cardiac hypertrophy markers, {beta}-myosin heavy chain ({beta}-MHC), and atrial natriuretic factor (ANF), which were significant at 2 months. Similarly, plasma and tissue ET-1 expression was significantly elevated at 2 months and increased further with age. Second, AhR null mice were treated with ET{sub A} receptor antagonist, BQ-123 (100 nmol/kg/day), for 7, 28, or 58 days and blood pressure, cardiac fibrosis, and cardiac hypertrophy assessed, respectively. BQ-123 for 7 days significantly reduced mean arterial pressure in conscious, catheterized mice. BQ-123 for 28 days significantly reduced the histological appearance of cardiac fibrosis. Treatment for 58 days significantly reduced cardiac mass, assessed by heart weight, echocardiography, and {beta}-MHC and ANF expression; and reduced cardiac fibrosis as determined by osteopontin and collagen I mRNA expression. These findings establish ET-1 and the ET{sub A} receptor as primary determinants of hypertension and cardiac pathology in AhR null mice.

  17. Integration of Genome-Wide Computation DRE Search, AhR ChIP-chip and Gene Expression Analyses of TCDD-Elicited Responses in the Mouse Liver

    PubMed Central

    2011-01-01

    Background The aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor (TF) that mediates responses to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Integration of TCDD-induced genome-wide AhR enrichment, differential gene expression and computational dioxin response element (DRE) analyses further elucidate the hepatic AhR regulatory network. Results Global ChIP-chip and gene expression analyses were performed on hepatic tissue from immature ovariectomized mice orally gavaged with 30 μg/kg TCDD. ChIP-chip analysis identified 14,446 and 974 AhR enriched regions (1% false discovery rate) at 2 and 24 hrs, respectively. Enrichment density was greatest in the proximal promoter, and more specifically, within ± 1.5 kb of a transcriptional start site (TSS). AhR enrichment also occurred distal to a TSS (e.g. intergenic DNA and 3' UTR), extending the potential gene expression regulatory roles of the AhR. Although TF binding site analyses identified over-represented DRE sequences within enriched regions, approximately 50% of all AhR enriched regions lacked a DRE core (5'-GCGTG-3'). Microarray analysis identified 1,896 number of TCDD-responsive genes (|fold change| ≥ 1.5, P1(t) > 0.999). Integrating this gene expression data with our ChIP-chip and DRE analyses only identified 625 differentially expressed genes that involved an AhR interaction at a DRE. Functional annotation analysis of differentially regulated genes associated with AhR enrichment identified overrepresented processes related to fatty acid and lipid metabolism and transport, and xenobiotic metabolism, which are consistent with TCDD-elicited steatosis in the mouse liver. Conclusions Details of the AhR regulatory network have been expanded to include AhR-DNA interactions within intragenic and intergenic genomic regions. Moreover, the AhR can interact with DNA independent of a DRE core suggesting there are alternative mechanisms of AhR-mediated gene regulation. PMID:21762485

  18. The chlorinated AHR ligand 3,3′,4,4′,5-pentachlorobiphenyl (PCB126) promotes reactive oxygen species (ROS) production during embryonic development in the killifish (Fundulus heteroclitus)

    USGS Publications Warehouse

    Arzuaga, Xabier; Wassenberg, Deena; Giulio, Richard D.; Elskus, Adria

    2006-01-01

    Exposure to dioxin-like chemicals that activate the aryl hydrocarbon receptor (AHR) can result in increased cellular and tissue production of reactive oxygen species (ROS). Little is known of these effects during early fish development. We used the fish model, Fundulus heteroclitus, to determine if the AHR ligand and pro-oxidant 3,3′,4,4′,5-pentachlorobiphenyl (PCB126) can increase ROS production during killifish development, and to test a novel method for measuring ROS non-invasively in a living organism. The superoxide-sensitive fluorescent dye, dihydroethidium (DHE), was used to detect in ovo ROS production microscopically in developing killifish exposed to PCB126 or vehicle. Both in ovo CYP1A activity (ethoxyresorufin-o-deethylase, EROD) and in ovo ROS were induced by PCB126. In ovo CYP1A activity was inducible by PCB126 concentrations as low as 0.003 nM, with maximal induction occurring at 0.3 nM PCB126. These PCB126 concentrations also significantly increased in ovo ROS production in embryonic liver, ROS being detectable as early as 5 days post-fertilization. These data demonstrate that the pro-oxidant and CYP1A inducer, PCB126, increases both CYP1A activity and ROS production in developing killifish embryos. The superoxide detection assay (SoDA) described in this paper provides a semi-quantitative, easily measured, early indicator of altered ROS production that can be used in conjunction with simultaneous in ovo measurements of CYP1A activity and embryo development to explore functional relationships among biochemical, physiological and developmental responses to AHR ligands.

  19. Human activities change marine ecosystems by altering predation risk.

    PubMed

    Madin, Elizabeth M P; Dill, Lawrence M; Ridlon, April D; Heithaus, Michael R; Warner, Robert R

    2016-01-01

    In ocean ecosystems, many of the changes in predation risk - both increases and decreases - are human-induced. These changes are occurring at scales ranging from global to local and across variable temporal scales. Indirect, risk-based effects of human activity are known to be important in structuring some terrestrial ecosystems, but these impacts have largely been neglected in oceans. Here, we synthesize existing literature and data to explore multiple lines of evidence that collectively suggest diverse human activities are changing marine ecosystems, including carbon storage capacity, in myriad ways by altering predation risk. We provide novel, compelling evidence that at least one key human activity, overfishing, can lead to distinct, cascading risk effects in natural ecosystems whose magnitude exceeds that of presumed lethal effects and may account for previously unexplained findings. We further discuss the conservation implications of human-caused indirect risk effects. Finally, we provide a predictive framework for when human alterations of risk in oceans should lead to cascading effects and outline a prospectus for future research. Given the speed and extent with which human activities are altering marine risk landscapes, it is crucial that conservation and management policy considers the indirect effects of these activities in order to increase the likelihood of success and avoid unfortunate surprises. PMID:26448058

  20. Human activities change marine ecosystems by altering predation risk.

    PubMed

    Madin, Elizabeth M P; Dill, Lawrence M; Ridlon, April D; Heithaus, Michael R; Warner, Robert R

    2016-01-01

    In ocean ecosystems, many of the changes in predation risk - both increases and decreases - are human-induced. These changes are occurring at scales ranging from global to local and across variable temporal scales. Indirect, risk-based effects of human activity are known to be important in structuring some terrestrial ecosystems, but these impacts have largely been neglected in oceans. Here, we synthesize existing literature and data to explore multiple lines of evidence that collectively suggest diverse human activities are changing marine ecosystems, including carbon storage capacity, in myriad ways by altering predation risk. We provide novel, compelling evidence that at least one key human activity, overfishing, can lead to distinct, cascading risk effects in natural ecosystems whose magnitude exceeds that of presumed lethal effects and may account for previously unexplained findings. We further discuss the conservation implications of human-caused indirect risk effects. Finally, we provide a predictive framework for when human alterations of risk in oceans should lead to cascading effects and outline a prospectus for future research. Given the speed and extent with which human activities are altering marine risk landscapes, it is crucial that conservation and management policy considers the indirect effects of these activities in order to increase the likelihood of success and avoid unfortunate surprises.

  1. Intrinsic Brain Activity in Altered States of Consciousness

    PubMed Central

    Boly, M.; Phillips, C.; Tshibanda, L.; Vanhaudenhuyse, A.; Schabus, M.; Dang-Vu, T.T.; Moonen, G.; Hustinx, R.; Maquet, P.; Laureys, S.

    2010-01-01

    Spontaneous brain activity has recently received increasing interest in the neuroimaging community. However, the value of resting-state studies to a better understanding of brain–behavior relationships has been challenged. That altered states of consciousness are a privileged way to study the relationships between spontaneous brain activity and behavior is proposed, and common resting-state brain activity features observed in various states of altered consciousness are reviewed. Early positron emission tomography studies showed that states of extremely low or high brain activity are often associated with unconsciousness. However, this relationship is not absolute, and the precise link between global brain metabolism and awareness remains yet difficult to assert. In contrast, voxel-based analyses identified a systematic impairment of associative frontoparieto–cingulate areas in altered states of consciousness, such as sleep, anesthesia, coma, vegetative state, epileptic loss of consciousness, and somnambulism. In parallel, recent functional magnetic resonance imaging studies have identified structured patterns of slow neuronal oscillations in the resting human brain. Similar coherent blood oxygen level–dependent (BOLD) systemwide patterns can also be found, in particular in the default-mode network, in several states of unconsciousness, such as coma, anesthesia, and slow-wave sleep. The latter results suggest that slow coherent spontaneous BOLD fluctuations cannot be exclusively a reflection of conscious mental activity, but may reflect default brain connectivity shaping brain areas of most likely interactions in a way that transcends levels of consciousness, and whose functional significance remains largely in the dark. PMID:18591474

  2. Characterization testing of a 40 Ahr bipolar nickel hydrogen battery

    NASA Technical Reports Server (NTRS)

    Brewer, Jeffrey C.; Manzo, Michelle A.; Gahn, Randall F.

    1989-01-01

    In a continuing effort to develop NiH2 bipolar technology to a point where it can be used efficiently in space flight, testing of a second 40 Ahr, 10-cell bipolar battery has begun. This battery has undergone extensive characterization testing to determine the effects of such operating parameters as charge and discharge rates, temperature, and pressure. The fundamental design of this actively cooled bipolar battery is the same as the first battery. Most of the individual components, however, are from different manufacturers. Different testing procedures as well as certain unique battery characteristics make it difficult to directly compare the two sets of results. In general, the performance of this battery throughout characterization produced expected results. The main differences seen between the first and second batteries occurred during the high-rate discharge portion of the test matrix. The first battery also had poor high-rate discharge results, although better than those of the second battery. Minor changes were made to the battery frame design used for the first battery in an attempt to allow better gas access to the reaction sites for the second build and hopefully improve performance. The changes, however, did not improve the performance of the second battery and could have possibly contributed to the poorer performance that was observed. There are other component differences that could have contributed to the poorer performance of the second battery. The H2 electrode in the second battery was constructed with a Goretex backing which could have limited the high-rate current flow. The gas screen in the second battery had a larger mesh which again could have limited the high-rate current flow. Small scale 2 x 2 batteries are being tested to evaluate the effects of the component variations.

  3. Analysis of the AHR gene proximal promoter GGGGC-repeat polymorphism in lung, breast, and colon cancer

    SciTech Connect

    Spink, Barbara C.; Bloom, Michael S.; Wu, Susan; Sell, Stewart; Schneider, Erasmus; Ding, Xinxin; Spink, David C.

    2015-01-01

    The aryl hydrocarbon receptor (AhR) regulates expression of numerous genes, including those of the CYP1 gene family. With the goal of determining factors that control AHR gene expression, our studies are focused on the role of the short tandem repeat polymorphism, (GGGGC){sub n}, located in the proximal promoter of the human AHR gene. When luciferase constructs containing varying GGGGC repeats were transfected into cancer cell lines derived from the lung, colon, and breast, the number of GGGGC repeats affected AHR promoter activity. The number of GGGGC repeats was determined in DNA from 327 humans and from 38 samples representing 5 species of non-human primates. In chimpanzees and 3 species of macaques, only (GGGGC){sub 2} alleles were observed; however, in western gorilla, (GGGGC){sub n} alleles with n = 2, 4, 5, 6, 7, and 8 were identified. In all human populations examined, the frequency of (GGGGC){sub n} was n = 4 > 5 ≫ 2, 6. When frequencies of the (GGGGC){sub n} alleles in DNA from patients with lung, colon, or breast cancer were evaluated, the occurrence of (GGGGC){sub 2} was found to be 8-fold more frequent among lung cancer patients in comparison with its incidence in the general population, as represented by New York State neonates. Analysis of matched tumor and non-tumor DNA samples from the same individuals provided no evidence of microsatellite instability. These studies indicate that the (GGGGC){sub n} short tandem repeats are inherited, and that the (GGGGC){sub 2} allele in the AHR proximal promoter region should be further investigated with regard to its potential association with lung cancer susceptibility. - Highlights: • The AHR proximal promoter contains a polymorphism, (GGGGC){sub n}, where n = 4 > 5 ≫ 2, 6 • Matched tumor and non-tumor DNA did not show (GGGGC){sub n} microsatellite instability • AHR promoter activity of a construct with (GGGGC){sub 2} was lower than that of (GGGGC){sub 4} • The frequency of (GGGGC){sub 2} in lung

  4. Biological effects of 6-formylindolo[3,2-b]carbazole (FICZ) in vivo are enhanced by loss of CYP1A function in an Ahr2-dependent manner.

    PubMed

    Wincent, Emma; Kubota, Akira; Timme-Laragy, Alicia; Jönsson, Maria E; Hahn, Mark E; Stegeman, John J

    2016-06-15

    6-Formylindolo[3,2-b]carbazole (FICZ) is a potent aryl hydrocarbon receptor (AHR) agonist that is efficiently metabolized by AHR-regulated cytochrome P4501 enzymes. FICZ is a proposed physiological AHR ligand that induces its own degradation as part of a regulatory negative feedback loop. In vitro studies in cells show that CYP1 inhibition in the presence of FICZ results in enhanced AHR activation, suggesting that FICZ accumulates in the cell when its metabolism is blocked. We used zebrafish (Danio rerio) embryos to investigate the in vivo effects of FICZ when CYP1A is knocked down or inhibited. Embryos were injected with morpholino antisense oligonucleotides targeting CYP1A (CYP1A-MO), Ahr2, or a combination of both. FICZ exposure of non-injected embryos or embryos injected with control morpholino had little effect. In CYP1A-MO-injected embryos, however, FICZ dramatically increased mortality, incidence and severity of pericardial edema and circulation failure, reduced hatching frequency, blocked swim bladder inflation, and strongly potentiated expression of Ahr2-regulated genes. These effects were substantially reduced in embryos with a combined knockdown of Ahr2 and CYP1A, indicating that the toxicity was mediated at least partly by Ahr2. Co-exposure to the CYP1 inhibitor alpha-naphthoflavone (αNF) and FICZ had similar effects as the combination of CYP1A-MO and FICZ. HPLC analysis of FICZ-exposed embryos showed increased levels of FICZ after concomitant CYP1A-MO injection or αNF co-exposure. Together, these results show that a functioning CYP1/AHR feedback loop is crucial for regulation of AHR signaling by a potential physiological ligand in vivo and further highlights the role of CYP1 enzymes in regulating biological effects of FICZ.

  5. Altered Spontaneous Brain Activity in Betel Quid Dependence

    PubMed Central

    Liu, Tao; Li, Jian-jun; Zhao, Zhong-yan; Yang, Guo-shuai; Pan, Meng-jie; Li, Chang-qing; Pan, Su-yue; Chen, Feng

    2016-01-01

    Abstract It has been suggested by the first voxel-based morphometry investigation that betel quid dependence (BQD) individuals are presented with brain structural changes in previous reports, and there may be a neurobiological basis for BQD individuals related to an increased risk of executive dysfunction and disinhibition, subjected to the reward system, cognitive system, and emotion system. However, the effects of BQD on neural activity remain largely unknown. Individuals with impaired cognitive control of behavior often reveal altered spontaneous cerebral activity in resting-state functional magnetic resonance imaging and those changes are usually earlier than structural alteration. Here, we examined BQD individuals (n = 33) and age-, sex-, and education-matched healthy control participants (n = 32) in an resting-state functional magnetic resonance imaging study to observe brain function alterations associated with the severity of BQD. Amplitude of low-frequency fluctuation (ALFF) and regional homogeneity (ReHo) values were both evaluated to stand for spontaneous cerebral activity. Gray matter volumes of these participants were also calculated for covariate. In comparison with healthy controls, BQD individuals demonstrated dramatically decreased ALFF and ReHo values in the prefrontal gurus along with left fusiform, and increased ALFF and ReHo values in the primary motor cortex area, temporal lobe as well as some regions of occipital lobe. The betel quid dependence scores (BQDS) were negatively related to decreased activity in the right anterior cingulate. The abnormal spontaneous cerebral activity revealed by ALFF and ReHo calculation excluding the structural differences in patients with BQD may help us probe into the neurological pathophysiology underlying BQD-related executive dysfunction and disinhibition. Diminished spontaneous brain activity in the right anterior cingulate cortex may, therefore, represent a biomarker of BQD individuals. PMID

  6. Analysis of the AHR gene proximal promoter GGGGC-repeat polymorphism in lung, breast, and colon cancer.

    PubMed

    Spink, Barbara C; Bloom, Michael S; Wu, Susan; Sell, Stewart; Schneider, Erasmus; Ding, Xinxin; Spink, David C

    2015-01-01

    The aryl hydrocarbon receptor (AhR) regulates expression of numerous genes, including those of the CYP1 gene family. With the goal of determining factors that control AHR gene expression, our studies are focused on the role of the short tandem repeat polymorphism, (GGGGC)n, located in the proximal promoter of the human AHR gene. When luciferase constructs containing varying GGGGC repeats were transfected into cancer cell lines derived from the lung, colon, and breast, the number of GGGGC repeats affected AHR promoter activity. The number of GGGGC repeats was determined in DNA from 327 humans and from 38 samples representing 5 species of non-human primates. In chimpanzees and 3 species of macaques, only (GGGGC)2 alleles were observed; however, in western gorilla, (GGGGC)n alleles with n=2, 4, 5, 6, 7, and 8 were identified. In all human populations examined, the frequency of (GGGGC)n was n=4>5≫2, 6. When frequencies of the (GGGGC)n alleles in DNA from patients with lung, colon, or breast cancer were evaluated, the occurrence of (GGGGC)2 was found to be 8-fold more frequent among lung cancer patients in comparison with its incidence in the general population, as represented by New York State neonates. Analysis of matched tumor and non-tumor DNA samples from the same individuals provided no evidence of microsatellite instability. These studies indicate that the (GGGGC)n short tandem repeats are inherited, and that the (GGGGC)2 allele in the AHR proximal promoter region should be further investigated with regard to its potential association with lung cancer susceptibility.

  7. In vitro re-expression of the aryl hydrocarbon receptor (Ahr) in cultured Ahr-deficient mouse antral follicles partially restores the phenotype to that of cultured wild-type mouse follicles

    PubMed Central

    Ziv-Gal, A; Gao, L.; Karman, B.N.; Flaws, J.A.

    2014-01-01

    Background The aryl hydrocarbon receptor (AHR) mediates the toxic effects of various endocrine disrupting chemicals. In female mice, global deletion of the Ahr (AhrKO) results in slow growth of ovarian antral follicles. No studies, however, have examined whether injection of the Ahr restores the phenotypes of cultured AhrKO ovarian antral follicles to wild-type levels. Methods We developed a system to construct a recombinant adenovirus containing the Ahr to re-express the Ahr in AhrKO granulosa cells and whole antral follicles. We then compared follicle growth and levels of factors in the AHR signaling pathway (Ahr, Ahrr, Cyp1a1, and Cyp1b1) in wild-type, AhrKO, and Ahr re-expressed follicles. Further, we compared the response to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in wild-type, AhrKO, and Ahr re-expressed follicles. Results AdAhr injection into AhrKO follicles partially restored their growth pattern to wild-type levels. Further, Ahr re-expressed follicles had significantly higher levels of Ahr, Ahrr, Cyp1a1, and Cyp1b1 compared to wild-type follicles. Upon TCDD treatment, only Cyp1a1 levels were significantly higher in Ahr re-expressed follicles compared to the levels in wild-type follicles. Conclusion Our system of re-expression of the Ahr partially restores follicle growth and transcript levels of factors in the AHR signaling pathway to wild-type levels. PMID:25500125

  8. Sequence and in vitro function of chicken, ring-necked pheasant, and Japanese quail AHR1 predict in vivo sensitivity to dioxins.

    PubMed

    Farmahin, Reza; Wu, Dongmei; Crump, Doug; Hervé, Jessica C; Jones, Stephanie P; Hahn, Mark E; Karchner, Sibel I; Giesy, John P; Bursian, Steven J; Zwiernik, Matthew J; Kennedy, Sean W

    2012-03-01

    There are large differences in sensitivity to the toxic and biochemical effects of dioxins and dioxin-like compounds (DLCs) among vertebrates. Previously, we demonstrated that the difference in sensitivity between domestic chicken (Gallus gallus domesticus) and common tern (Sterna hirundo) to aryl hydrocarbon receptor 1 (AHR1)-dependent changes in gene expression following exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) is based upon the identities of the amino acids at two sites within the ligand binding domain of AHR1 (chicken--highly sensitive; Ile324_Ser380 vs common tern--250-fold less sensitive than chicken; Val325_Ala381). Here, we tested the hypotheses that (i) the sensitivity of other avian species to TCDD, 2,3,4,7,8-pentachlorodibenzofuran (PeCDF), and 2,3,7,8-tetrachlorodibenzofuran (TCDF) is also determined by the amino acids at sites that are equivalent to sites 324 and 380 in chicken, and (ii) Ile324_Ala380 and Val324_Ser380 genotypes confer intermediate sensitivity to DLCs in birds. We compared ligand-induced transactivation function of full-length AHR1s from chicken, common tern, ring-necked pheasant (Phasianus colchicus; Ile324_Ala380) and Japanese quail (Coturnix japonica; Val324_Ala380), and three Japanese quail AHR1 mutants. The results support our hypothesis that avian species can be grouped into three general classes of sensitivity to DLCs. Both AHR1 genotype and in vitro transactivation assays predict in vivo sensitivity. Contrary to the assumption that TCDD is the most potent DLC, PeCDF was more potent than TCDD at activating Japanese quail (13- to 26-fold) and common tern (23- to 30-fold) AHR1. Our results support and expand previous in vitro and in vivo work that demonstrated ligand-dependent species differences in AHR1 affinity. The findings and methods will be of use for DLC risk assessments.

  9. Altered brain activity for phonological manipulation in dyslexic Japanese children.

    PubMed

    Kita, Yosuke; Yamamoto, Hisako; Oba, Kentaro; Terasawa, Yuri; Moriguchi, Yoshiya; Uchiyama, Hitoshi; Seki, Ayumi; Koeda, Tatsuya; Inagaki, Masumi

    2013-12-01

    Because of unique linguistic characteristics, the prevalence rate of developmental dyslexia is relatively low in the Japanese language. Paradoxically, Japanese children have serious difficulty analysing phonological processes when they have dyslexia. Neurobiological deficits in Japanese dyslexia remain unclear and need to be identified, and may lead to better understanding of the commonality and diversity in the disorder among different linguistic systems. The present study investigated brain activity that underlies deficits in phonological awareness in Japanese dyslexic children using functional magnetic resonance imaging. We developed and conducted a phonological manipulation task to extract phonological processing skills and to minimize the influence of auditory working memory on healthy adults, typically developing children, and dyslexic children. Current experiments revealed that several brain regions participated in manipulating the phonological information including left inferior and middle frontal gyrus, left superior temporal gyrus, and bilateral basal ganglia. Moreover, dyslexic children showed altered activity in two brain regions. They showed hyperactivity in the basal ganglia compared with the two other groups, which reflects inefficient phonological processing. Hypoactivity in the left superior temporal gyrus was also found, suggesting difficulty in composing and processing phonological information. The altered brain activity shares similarity with those of dyslexic children in countries speaking alphabetical languages, but disparity also occurs between these two populations. These are initial findings concerning the neurobiological impairments in dyslexic Japanese children.

  10. Imatinib Activates Pathological Hypertrophy by Altering Myocyte Calcium Regulation

    PubMed Central

    Barr, Larry; Makarewich, Catherine A.; Berretta, Remus M.; Gao, Hui; Troupes, Constantine D.; Woitek, Felix; Recchia, Fabio; Kubo, Hajime; Force, Thomas; Houser, Steven R.

    2014-01-01

    Background Imatinib mesylate is a selective tyrosine-kinase inhibitor used in the treatment of multiple cancers, most notably chronic myelogenous leukemia (CML). There is evidence that imatinib can induce cardiotoxicity in cancer patients. Our hypothesis is that imatinib alters calcium regulatory mechanisms and can contribute to development of pathological cardiac hypertrophy. Methods/Results Neonatal rat ventricular myocytes (NRVMs) were treated with clinical doses (Low: 2µM, High: 5µM) of imatinib and assessed for molecular changes. Imatinib increased peak systolic Ca2+ and Ca2+ transient decay rates and Western analysis revealed significant increases in phosphorylation of phospholamban (Thr-17) and the ryanodine receptor (Ser-2814), signifying activation of CaMKII. Imatinib significantly increased NRVM volume as assessed by Coulter counter, myocyte surface area and ANP abundance seen by Western. Imatinib induced cell death, but did not activate the classical apoptotic program as assessed by caspase-3 cleavage, indicating a necrotic mechanism of death in myocytes. We expressed AdNFATc3-GFP in NRVMS and showed imatinib treatment significantly increased NFAT translocation that was inhibited by the calcineurin inhibitor FK506 or CaMKII inhibitors. Conclusion These data show that imatinib can activate pathological hypertrophic signaling pathways by altering intracellular Ca2+ dynamics. This is likely a contributing mechanism for the adverse cardiac effects of imatinib. PMID:24931551

  11. Thalidomide combined with irradiation alters the activity of two proteases.

    PubMed

    Şimşek, Ece; Aydemir, Esra; Korcum, Aylin Fidan; Fişkın, Kayahan

    2015-02-01

    The aim of the present study was to investigate the effects of thalidomide, a drug known for its anti‑angiogenic and antitumor properties, at its cytotoxic dose previously determined as 40 µg/ml (according to four cytotoxic test results). The effect of the drug alone and in combination with radiotherapy using Cobalt 60 (60Co) at 45 Gy on the enzymatic activity of substance‑P degrading A disintegrin and metalloproteinase (ADAM)10 and neprilysin (NEP) was investigated in the mouse breast cancer cell lines 4T1 and 4T1 heart metastases post‑capsaicin (4THMpc). Thalidomide (40 µg/ml) exerted differing effects on the activities of ADAM10 and NEP enzymes. In 4T1 cells, 40 µg/ml thalidomide alone did not alter ADAM10 enzyme activity. 60Co irradiation at 45 Gy alone caused a 42% inhibition in ADAM10 activity, however, the inhibition increased to 89% when combined therapy was used. By contrast, in the 4THMpc cell line, 40 µg/ml thalidomide alone induced a 66.6% increase in ADAM10 enzyme activity. Radiotherapy alone and thalidomide with 60Co combined therapy caused a 33.3 and 40% inhibition of ADAM10 activity, respectively. In 4T1 cells, thalidomide alone caused a 40.9% increase in NEP activity. Radiation therapy alone or in combination with the drug caused a 40.7% increase in NEP activity. In more aggressive 4THMpc cells, thalidomide alone caused a 26.6% increase in NEP activity. Radiotherapy alone and combined therapy caused a 33.3 and 37% increase in enzyme activity, respectively. To the best of our knowledge, the present study is the first to demonstrate that thalidomide alone or in combination with radiotherapy exhibits significant cytotoxic effects on 4T1 and 4THMpc mouse breast cancer cell lines indicating that this drug affects the enzymatic activity of ADAM10 and NEP in vitro.

  12. Psychiatric implications of altered limbic-hypothalamic-pituitary-adrenocortical activity.

    PubMed

    Holsboer, F

    1989-01-01

    Hormones of the limbic-hypothalamic-pituitary-adrenocortical (LHPA) system are much involved in central nervous system regulation. The major LHPA neuropeptides, corticotropin-releasing hormone (CRH), vasopressin (AVP) and corticotropin (ACTH) do not only coordinate the neuroendocrine response to stress, but also induce behavioral adaptation. Transcription and post-translational processing of these neuropeptides is regulated by corticosteroids secreted from the adrenal cortex after stimulation by ACTH and other proopiomelanocortin derived peptides. These steroids play a key role as regulators of cell development, homeostatic maintenance and adaptation to environmental challenges. They execute vitally important actions through genomic effects resulting in altered gene expression and nongenomic effects leading to altered neuronal excitability. Since excessive secretory activity of this particular neuroendocrine system is part of an acute stress response or depressive symptom pattern, there is good reason to suspect that central actions of these steroids and peptides are involved in pathophysiology determining the clinical phenotype, drug response and relapse liability. This overview summarizes the clinical neuroendocrine investigations of the author and his collaborators, while they worked at the Department of Psychiatry in Mainz. The major conclusions from this work were: (1) aberrant hormonal responses to challenges with dexamethasone, ACTH or CRH are reflecting altered brain physiology in affective illness and related disorders; (2) hormones of the LHPA axis influence also nonendocrine behavioral systems such as sleep EEG; (3) physiologically significant interactions exist between LHPA hormones, the thyroid, growth hormone, gonadal and other neuroendocrine systems; (4) hormones of the LHPA axis constitute a bidirectional link between immunoregulation and brain activity; and (5) future psychiatric research topics such as molecular genetics of affective disorders

  13. Low HDL cholesterol, aggression and altered central serotonergic activity.

    PubMed

    Buydens-Branchey, L; Branchey, M; Hudson, J; Fergeson, P

    2000-03-01

    Many studies support a significant relation between low cholesterol levels and poor impulse, aggression and mood control. Evidence exists also for a causal link between low brain serotonin (5-HT) activity and these behaviors. Mechanisms linking cholesterol and hostile or self-destructive behavior are unknown, but it has been suggested that low cholesterol influences 5-HT function. This study was designed to explore the relationship between plasma cholesterol, measures of impulsivity and aggression, and indices of 5-HT function in personality disordered cocaine addicts. Thirty-eight hospitalized male patients (age 36.8+/-7.1) were assessed with the DSM-III-R, the Buss-Durkee Hostility Inventory (BDHI), the Barratt Impulsiveness Scale (BIS) and the Brown-Goodwin Assessment for Life History of Aggression. Fasting basal cholesterol (total, LDL and HDL) was determined 2 weeks after cocaine discontinuation. On the same day 5-HT function was assessed by neuroendocrine (cortisol and prolactin) and psychological (NIMH and 'high' self-rating scales) responses following meta-chlorophenylpiperazine (m-CPP) challenges. Reduced neuroendocrine responses, 'high' feelings and increased 'activation-euphoria' following m-CPP have been interpreted as indicating 5-HT alterations in a variety of psychiatric conditions. Significantly lower levels of HDL cholesterol were found in patients who had a history of aggression (P=0.005). Lower levels of HDL cholesterol were also found to be significantly associated with more intense 'high' and 'activation-euphoria' responses as well as with blunted cortisol responses to m-CPP (P=0.033, P=0.025 and P=0.018, respectively). This study gives further support to existing evidence indicating that in some individuals, the probability of exhibiting impulsive and violent behaviors may be increased when cholesterol is low. It also suggests that low cholesterol and alterations in 5-HT activity may be causally related.

  14. Combined chemical and toxicological long-term monitoring for AhR agonists with SPMD-based virtual organisms in drinking water Danjiangkou Reservoir, China.

    PubMed

    Wang, Jingxian; Song, Guoqiang; Li, Aimin; Henkelmann, Bernhard; Pfister, Gerd; Tong, Anthony Z; Schramm, Karl-Werner

    2014-08-01

    SPMD-based virtual organisms (VOs) were employed for time-integrating, long-term sampling combined biological and chemical analyses for exposure assessment of hydrophobic organic pollutants (HOPs) in a drinking water reservoir, China. The SPMDs were deployed at four and five sites in the Danjiangkou (DJK) reservoir over two periods of 26 and 31 d to sequester the hydrophobic contaminants in water. The chosen bioassay response for the extracts of the SPMDs, the induction of 7-ethoxyresorufin-o-deethylase (EROD) was assayed using a rat hepatoma cell line (H4IIE). The known aryl hydrocarbon receptor (AhR) agonists PAHs and PCBs were analyzed by HRGC/HRMS instrument. The cause-effect relationship between the observed AhR activities and chemical concentrations of detected AhR agonists was examined. The results show that the extracts from the SPMD samples could induce AhR activity significantly, whereas the chemically derived 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) equivalent (TEQcal) was not correlated with the bioassay-derived TCDD equivalent (TEQbio). The known AhR agonists could only account for 2-10% of the observed AhR responses among which the contribution of PCBs could almost be neglected. Unidentified AhR-active compounds represented a greater proportion of the TCDD equivalent (TCDD-EQ) in SPMD samples from DJK. Based on the first assessment, the VO followed by the combination of chemical and biological analyses emerges as a resource efficient water monitoring device in ecotoxicological assessment for toxicologically relevant compounds which are readily available for uptake by resident aquatic biota in drinking water resources. PMID:24548649

  15. Combined chemical and toxicological long-term monitoring for AhR agonists with SPMD-based virtual organisms in drinking water Danjiangkou Reservoir, China.

    PubMed

    Wang, Jingxian; Song, Guoqiang; Li, Aimin; Henkelmann, Bernhard; Pfister, Gerd; Tong, Anthony Z; Schramm, Karl-Werner

    2014-08-01

    SPMD-based virtual organisms (VOs) were employed for time-integrating, long-term sampling combined biological and chemical analyses for exposure assessment of hydrophobic organic pollutants (HOPs) in a drinking water reservoir, China. The SPMDs were deployed at four and five sites in the Danjiangkou (DJK) reservoir over two periods of 26 and 31 d to sequester the hydrophobic contaminants in water. The chosen bioassay response for the extracts of the SPMDs, the induction of 7-ethoxyresorufin-o-deethylase (EROD) was assayed using a rat hepatoma cell line (H4IIE). The known aryl hydrocarbon receptor (AhR) agonists PAHs and PCBs were analyzed by HRGC/HRMS instrument. The cause-effect relationship between the observed AhR activities and chemical concentrations of detected AhR agonists was examined. The results show that the extracts from the SPMD samples could induce AhR activity significantly, whereas the chemically derived 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) equivalent (TEQcal) was not correlated with the bioassay-derived TCDD equivalent (TEQbio). The known AhR agonists could only account for 2-10% of the observed AhR responses among which the contribution of PCBs could almost be neglected. Unidentified AhR-active compounds represented a greater proportion of the TCDD equivalent (TCDD-EQ) in SPMD samples from DJK. Based on the first assessment, the VO followed by the combination of chemical and biological analyses emerges as a resource efficient water monitoring device in ecotoxicological assessment for toxicologically relevant compounds which are readily available for uptake by resident aquatic biota in drinking water resources.

  16. Pharmacological activity of metal binding agents that alter copper bioavailability

    PubMed Central

    Helsel, Marian E.

    2015-01-01

    Iron, copper and zinc are required nutrients for many organisms but also potent toxins if misappropriated. An overload of any of these metals can be cytotoxic and ultimately lead to organ failure, whereas deficiencies can result in anemia, weakened immune system function, and other medical conditions. Cellular metal imbalances have been implicated in neurodegenerative diseases, cancer and infection. It is therefore critical for living organisms to maintain careful control of both the total levels and subcellular distributions of these metals to maintain healthy function. This perspective explores several strategies envisioned to alter the bioavailability of metal ions by using synthetic metal-binding agents targeted for diseases where misappropriated metal ions are suspected of exacerbating cellular damage. Specifically, we discuss chemical properties that influence the pharmacological outcome of a subset of metal-binding agents known as ionophores, and review several examples that have shown multiple pharmacological activities in metal-related diseases, with a specific focus on copper. PMID:25797044

  17. Exposure to mercury alters early activation events in fish leukocytes.

    PubMed Central

    MacDougal, K C; Johnson, M D; Burnett, K G

    1996-01-01

    Although fish in natural populations may carry high body burdens of both organic and inorganic mercury, the effects of this divalent metal on such lower vertebrates is poorly understood. In this report, inorganic mercury in the form of mercuric chloride (HgCl2) is shown to produce both high-dose inhibition and low-dose activation of leukocytes in a marine teleost fish, Sciaenops ocellatus. Concentrations of inorganic mercury > or = 10 microM suppressed DNA synthesis and induced rapid influx of radiolabeled calcium, as well as tyrosine phosphorylation of numerous cellular proteins. Lower concentrations (0.1-1 microM) of HgCl2 that activated cell growth also induced a slow sustained rise in intracellular calcium in cells loaded with the calcium indicator dye fura-2, but did not produce detectable tyrosine phosphorylation of leukocyte proteins. These studies support the possibility that subtoxic doses of HgCl2 may inappropriately activate teleost leukocytes, potentially altering the processes that regulate the magnitude and specificity of the fish immune response to environmental pathogens. Images Figure 1. Figure 2. Figure 3. Figure 4. Figure 5. Figure 6. Figure 7. PMID:8930553

  18. Altered resting-state activity in seasonal affective disorder.

    PubMed

    Abou Elseoud, Ahmed; Nissilä, Juuso; Liettu, Anu; Remes, Jukka; Jokelainen, Jari; Takala, Timo; Aunio, Antti; Starck, Tuomo; Nikkinen, Juha; Koponen, Hannu; Zang, Yu-Feng; Tervonen, Osmo; Timonen, Markku; Kiviniemi, Vesa

    2014-01-01

    At present, our knowledge about seasonal affective disorder (SAD) is based mainly up on clinical symptoms, epidemiology, behavioral characteristics and light therapy. Recently developed measures of resting-state functional brain activity might provide neurobiological markers of brain disorders. Studying functional brain activity in SAD could enhance our understanding of its nature and possible treatment strategies. Functional network connectivity (measured using ICA-dual regression), and amplitude of low-frequency fluctuations (ALFF) were measured in 45 antidepressant-free patients (39.78 ± 10.64, 30 ♀, 15 ♂) diagnosed with SAD and compared with age-, gender- and ethnicity-matched healthy controls (HCs) using resting-state functional magnetic resonance imaging. After correcting for Type 1 error at high model orders (inter-RSN correction), SAD patients showed significantly increased functional connectivity in 11 of the 47 identified RSNs. Increased functional connectivity involved RSNs such as visual, sensorimotor, and attentional networks. Moreover, our results revealed that SAD patients compared with HCs showed significant higher ALFF in the visual and right sensorimotor cortex. Abnormally altered functional activity detected in SAD supports previously reported attentional and psychomotor symptoms in patients suffering from SAD. Further studies, particularly under task conditions, are needed in order to specifically investigate cognitive deficits in SAD.

  19. Age related alterations of adrenoreceptor activity in erythrocyte membrane.

    PubMed

    Lomsadze, G; Khetsuriani, R; Arabuli, M; Intskirveli, N; Sanikidze, T

    2011-06-01

    The aim of the study was the investigation of age-related functional alterations of adrenoreceptors and the effect of agonist and antagonist drugs on age related adrenoreceptor activity in erythrocyte membrane. The impact of isopropanol and propanol on functional activity β- adrenergic receptors in red blood cell membrane were studied in 50 practically healthy men--volunteers. (I group--75-89 years old, II group--22-30 years old). The EPR signals S1 and S2 were registered in red blood cell membrane samples after incubation with isopropanol and propanol respectively. It was found that decreasing sensitivity (functional activity) of red blood cells membrane adrenoreceptors comes with aging (S1old

  20. A Mutant Ahr Allele Protects the Embryonic Kidney from Hydrocarbon-Induced Deficits in Fetal Programming

    PubMed Central

    Nanez, Adrian

    2011-01-01

    Background: The use of experimental model systems has expedited the elucidation of pathogenetic mechanisms of renal developmental disease in humans and the identification of genes that orchestrate developmental programming during nephrogenesis. Objectives: We conducted studies to evaluate the role of AHR polymorphisms in the disruption of renal developmental programming by benzo(a)pyrene (BaP). Methods: We used metanephric cultures of C57BL/6J (C57) mice expressing the Ahrb-1 allele and B6.D2N-Ahrd/J (D2N) mice expressing a mutant allele deficient in ligand binding (Ahrd) to investigate molecular mechanisms of renal development. Deficits in fetal programming were evaluated in the offspring of pregnant mice treated with BaP during nephrogenesis. Results: Hydrocarbon challenge of metanephri from C57 mice altered Wilms’ tumor suppressor gene (Wt1) mRNA splice variant ratios and reduced mRNAs of the Wt1 transcriptional targets syndecan-1 (Sdc1) paired box gene 2 (Pax2), epidermal growth factor receptor (Egfr), and retinoic acid receptor, alpha (Rarα). These changes correlated with down-regulation of effectors of differentiation [secreted frizzled-related sequence protein 1 (Sfrp1), insulin-like growth factor 1 receptor (Igf1r), wingless-related MMTV-integration site 4 (Wnt4), Lim homeobox protein 1 (Lhx1), E-cadherin]. In contrast, metanephri from D2N mice were spared hydrocarbon-induced changes in Wt1 splice variant ratios and deficits of differentiation. We observed similar patterns of dysmorphogenesis and progressive loss of renal function at postnatal weeks 7 and 52 in the offspring of pregnant C57 but not D2N mice gavaged with 0.1 or 0.5 mg/kg BaP on gestation days 10–13. Conclusions: These findings support a functional link between AHR and WT1 in the regulation of renal morphogenesis and raise important questions about the contribution of human AHR polymorphisms to the fetal origins of adult-onset kidney disease. PMID:21803694

  1. Physical activity alters antioxidant status in exercising elderly subjects.

    PubMed

    Rousseau, Anne-Sophie; Margaritis, Irène; Arnaud, Josiane; Faure, Henri; Roussel, Anne-Marie

    2006-07-01

    Nutritional adequacy and physical activity are two aspects of a health-promoting lifestyle. Not much is known about antioxidant nutrient requirements for exercising elderly (EE) subjects. The question of whether exercise training alters the status of antioxidant vitamins as well as trace elements in elderly subjects and fails to balance the age-related increase in oxidative stress is addressed in this study. There were 18 EE (68.1+/-3.1 years), 7 sedentary elderly (SE; 70.4+/-5.0 years), 17 exercising young (EY; 31.2+/-7.1 years) and 8 sedentary young (SY; 27.1+/-5.8 years) subjects who completed 7-day food and activity records. Each subject's blood was sampled on Day 8. A similar selenium (Se) status but a higher erythrocyte glutathione peroxidase (GSH-Px) activity were found in EE subjects as compared with EY and SE subjects. Blood oxidized glutathione was higher and plasma total thiol was lower in EE subjects as compared with EY subjects. Mean vitamin C (167 vs. 106 mg/day), vitamin E (11.7 vs. 8.3 mg/day) and beta-carotene (4 vs. 2.4 mg/day) intakes were higher in EE subjects as compared with EY subjects. However, EE subjects exhibited the lowest plasma carotenoid concentrations, especially in beta-carotene, which was not related to intakes. Despite high intakes of antioxidant micronutrients, no adaptive mechanism able to counteract the increased oxidative stress in aging was found in EE subjects. Results on GSH-Px activity illustrate that the nature of the regulation of this biomarker of Se status is different in response to training and aging. These data also strongly suggest specific antioxidant requirements for athletes with advancing age, with a special attention to carotenoids.

  2. Alteration of spontaneous brain activity in COPD patients

    PubMed Central

    Zhang, Jiaxing; Chen, Ji; Yu, Qian; Fan, Cunxiu; Zhang, Ran; Lin, Jianzhong; Yang, Tianhe; Fan, Ming

    2016-01-01

    Background and objective Airflow limitation in chronic obstructive pulmonary disease (COPD) results in a decrease in oxygen transport to the brain. The aim of the present study was to explore the alteration of spontaneous brain activity induced by hypoxia in patients with COPD. Patients and methods Twenty-five stable patients with COPD and 25 matching healthy volunteers were investigated. Amplitude of low-frequency fluctuation (ALFF) of blood oxygenation level-dependent signal at resting state in the brain was analyzed using functional magnetic resonance imaging. Results Whole-brain analysis using functional magnetic resonance imaging revealed significant decreases in ALFF in the bilateral posterior cingulate gyri and right lingual gyrus and an increase in ALFF in the left postcentral gyrus of patients with COPD. After controlling for SaO2, patients with COPD only showed an increase in ALFF in the left postcentral gyrus. Region of interest analysis showed a decrease in ALFF in the left precentral gyrus and an increase in ALFF in the left caudate nucleus of patients with COPD. In all subjects, ALFF in the bilateral posterior cingulate gyri and right lingual gyrus showed positive correlations with visual reproduction. Conclusion We demonstrated abnormal spontaneous brain activity of patients with COPD, which may have a pathophysiologic meaning. PMID:27555761

  3. A potential endogenous ligand for the aryl hydrocarbon receptor has potent agonist activity in vitro and in vivo.

    PubMed

    Henry, E C; Bemis, J C; Henry, O; Kende, A S; Gasiewicz, T A

    2006-06-01

    The aryl hydrocarbon receptor (AhR) is best known as a mediator of toxicity of a diverse family of xenobiotic chemicals such as dioxins and PCBs. However, many naturally occurring compounds also activate AhR. One such compound, 2-(1'H-indole-3'-carbonyl)-thiazole-4-carboxylic acid methyl ester (ITE), was isolated from tissue and found to be potent in preliminary tests [J. Song, M. Clagett-Dame, R.E. Peterson, M.E. Hahn, W.M. Westler, R.R. Sicinski, H.F. DeLuca, Proc. Natl. Acad. Sci. USA 99 (2002) 14694-14699]. We have synthesized ITE and [(3)H]ITE and further evaluated its AhR activity in several in vitro and in vivo assays in comparison with the toxic ligand, TCDD. AhR in Hepa1c1c7 cell cytosol bound [(3)H]ITE with high affinity and the AhR.ITE complex formed in vitro bound dioxin response element (DRE) oligonucleotide as potently as TCDD.AhR. In cells treated with ITE, nuclear translocation of AhR, and induction of CYP1A1 protein and of a DRE-dependent luciferase reporter gene were observed. ITE administered to pregnant DRE-LacZ transgenic mice activated fetal AhR, observed as X-gal staining in the same sites as in TCDD-treated mice. However, unlike TCDD, ITE did not induce cleft palate or hydronephrosis. TCDD but not ITE induced thymic atrophy in young adult mice, but both ITE and TCDD caused similar loss of cells and alterations of cell profiles in cultured fetal thymi. These data demonstrate that ITE is a potent AhR agonist in cell extracts, cultured cells, and intact animals, but does not cause the toxicity associated with the more stable xenobiotic ligand, TCDD.

  4. Gene cloning and expression analysis of AhR and CYP4 from Pinctada martensii after exposed to pyrene.

    PubMed

    Du, Junqiao; Liao, Chenghong; Zhou, Hailong; Diao, Xiaoping; Li, Yuhu; Zheng, Pengfei; Wang, Fuqiang

    2015-10-01

    Pyrene, a typical polycyclic aromatic hydrocarbon, is a common pollutant in the marine environment. Polycyclic aromatic hydrocarbons initiate cellular detoxification in an exposed organism via the activation of the aryl hydrocarbon receptor (AhR). Subsequent metabolism of these xenobiotics is mainly by the cytochrome P450 enzymes of the phase I detoxification system. Full-length complementary DNA sequences from the pearl oyster Pinctada martensii (pm) encoding AhR and cytochrome P4 were cloned. The P. martensii AhR complementary DNA sequence constitutes an open reading frame that encodes for 848 amino acids. Sequence analysis indicated PmAhR showed high similarity with its homologues of other bivalve species. The cytochrome P(CYP)4 complementary DNA sequence of P. martensii constitutes an open reading frame that encodes for 489 amino acids. Quantitative real-time analysis detected both PmAhR and PmCYP4 messenger RNA expressions in the mantle, gill, hepatapancreas and adductor muscle of P. martensii exposed to pyrene. The highest transcript-band intensities of PmAhR and PmCYP4 were observed in the gill. Temporal expression of PmAhR and PmCYP4 messenger RNAs induction was observed in gills and increased between 3 and 5 days post exposure; then returned to control level. These results suggest that messenger RNAs of PmAhR and PmCYP4 in pearl oysters might be useful parameters for monitoring marine environment pyrene pollution.

  5. Suppression of Human B Cell Activation by 2,3,7,8-Tetrachlorodibenzo-p-dioxin Involves Altered Regulation of B Cell Lymphoma-6

    PubMed Central

    Phadnis-Moghe, Ashwini S.; Crawford, Robert B.; Kaminski, Norbert E.

    2015-01-01

    The environmental contaminant 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) produces marked suppression of the primary humoral immune response in virtually every animal species evaluated thus far. In addition, epidemiological studies performed in areas of dioxin contamination have identified an association between TCDD exposure and an increased incidence of non-Hodgkin’s lymphoma (NHL). Recent studies using an in vitro CD40 ligand model of human B cell differentiation have shown that TCDD impairs both B cell activation and differentiation. The present study extends these findings by identifying B cell lymphoma-6 [BCL-6] as a putative cellular target for deregulation by TCDD, which may contribute to suppression of B cell function as well as NHL. BCL-6 is a multifunctional transcriptional repressor frequently mutated in NHLs and known to regulate critical events of B cell activation and differentiation. In the presence of TCDD, BCL-6 protein levels were elevated and concurrently the same population of cells with high BCL-6 levels showed decreased CD80 and CD69 expression indicative of impaired cellular activation. The elevated BCL-6 levels resulted in a concomitant increase in BCL-6 DNA binding activity at its cognate binding site within an enhancer region for CD80. Furthermore, a small molecule inhibitor of BCL-6 activity reversed TCDD-mediated suppression of CD80 expression in human B cells. In the presence of a low-affinity ligand of the aryl hydrocarbon receptor (AHR), suppression of B cell activation and altered BCL-6 regulation were not observed. These results provide new mechanistic insights into the role of BCL-6 in the suppression of human B cell activation by TCDD. PMID:25543051

  6. Hematopoietic stem and progenitor cell activation during chronic dermatitis provoked by constitutively active aryl-hydrocarbon receptor driven by Keratin 14 promoter.

    PubMed

    Murakami, Shohei; Yamamoto, Masayuki; Motohashi, Hozumi

    2014-03-01

    Polycyclic aromatic hydrocarbons (PAHs) activate aryl-hydrocarbon receptor (AhR). Because PAHs are known as a risk factor for allergic diseases, PAH-induced AhR activation is expected to be involved in the development of the pathology. We previously generated transgenic mice expressing a constitutively active AhR (AhR-CA) under the control of Keratin 14 (K14) promoter (AhR-CA mouse). The mice develop chronic dermatitis with immune imbalance toward Th2 predominance, indicating that the AhR activation driven by K14 promoter provokes allergic response. Because hematopoietic cells actively participate in the development of allergic inflammation, it is important to understand the hematopoietic status under allergic conditions. To clarify how the K14 promoter-driven AhR activation influences hematopoiesis, we analyzed bone marrow and spleen of AhR-CA mice. We verified that AhR-CA was expressed in keratinocytes and thymic epithelial cells but not in hematopoietic cells. The AhR-CA mice with full-blown dermatitis exhibited leukocytosis and skewed differentiation of hematopoietic progenitor cells toward granulocyte-monocyte lineages. They also showed a significant expansion of short-term hematopoietic stem cells and multipotent progenitors and a subtle reduction in long-term hematopoietic stem cells (LT-HSCs). Their spleens were enlarged and abundantly accumulated hematopoietic stem and progenitor cells. AhR-CA mice at the early stage of dermatitis did not show leukocytosis or splenomegaly but exhibited the granulocyte-monocyte skewing and the reduction in LT-HSCs. Thus, AhR activation driven by K14 promoter already alters the hematopoietic differentiation and reduces LT-HSCs at the initial stage of dermatitis development. These results suggest that nonhematopoietic exposure to PAHs triggers allergic response and concomitantly affects hematopoiesis.

  7. PFOS elicits transcriptional responses of the ER, AHR and PPAR pathways in Oryzias melastigma in a stage-specific manner.

    PubMed

    Fang, Chao; Wu, Xinlong; Huang, Qiansheng; Liao, Yanyan; Liu, Liangpo; Qiu, Ling; Shen, Heqing; Dong, Sijun

    2012-01-15

    Perfluorooctane sulfonate (PFOS) is widely distributed in seawater. However, the effects of PFOS on important receptors involved in the toxicity of POPs have not been fully defined, especially for the embryonic stages of marine fish. In this study, we examined the transcriptional responses and PFOS accumulation in the marine medaka embryos at the early and late developmental stages of 4 and 10 dpf upon PFOS exposure (1, 4, and 16mg/L). PFOS accumulated in the embryos, and the embryonic burdens of PFOS at 10 dpf were markedly higher than those at 4 dpf. Moreover, thirteen genes involved in three important POPs-related receptor pathways, including ER, AHR and PPAR, were cloned and investigated. The mRNA expression levels of ERα and ERγ were not significantly altered, but the estrogenic marker genes were downregulated upon PFOS exposure at 4 dpf. Conversely, ERs and related marker genes all were significantly upregulated at 10 dpf. The expressions of ARNT and cyp1a were both upregulated at 4 dpf, while no obvious changes were detected at 10 dpf. The expressions of cyp19a and cyp19b were regulated by PFOS in a stage-specific manner. PFOS produced different effects on three isoforms of PPAR. PPARα and PPARβ were first inhibited at 4 dpf and were induced at 10 dpf. PFOS did not elicit a change in PPARγ expression at either stage. In conclusion, this study showed that PFOS has an estrogenic activity and endocrine-disruptive properties. Meanwhile, PFOS could elicit transcriptional responses on POPs-related pathways in a stage-specific manner.

  8. 75 FR 49550 - Fifth Meeting: RTCA Special Committee 219: Attitude and Heading Reference System (AHRS)

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-13

    ... Federal Aviation Administration Fifth Meeting: RTCA Special Committee 219: Attitude and Heading Reference...: Notice of RTCA Special Committee 219: Attitude and Heading Reference System (AHRS). SUMMARY: The FAA is... Heading Reference System (AHRS). DATES: The meeting will be held September 14-16, 2010 from 9 a.m. to 5...

  9. Differences in the action of lower and higher chlorinated polychlorinated naphthalene (PCN) congeners on estrogen dependent breast cancer cell line viability and apoptosis, and its correlation with Ahr and CYP1A1 expression.

    PubMed

    Gregoraszczuk, Ewa L; Barć, Justyna; Falandysz, Jerzy

    2016-07-29

    There are data showing that exposition to PCNs mixture increased incidence of gastrointestinal and respiratory neoplasms, but data regarding incidence of hormone-dependent cancer so far not shown. The objective was to determine if exposure to single lower and higher chlorinated PCN congeners is associated with altered proliferation and apoptosis of estrogen dependent breast cancer cells, and whether such effects are related to induction of AhR and CYP1A1 protein expression. MCF-7 cells were exposed to PCN 34, 39, 42, 46, 48, 52, 53, 54, 66, 67, 70, 71, 73 and 74 at concentrations of 100-10,000pg/ml. We evaluated the action of these PCN congeners on cell proliferation, DNA fragmentation and caspase-8,-9 activity. AhR and CYP1A1 protein expression and CYP1A1 activity was evaluated at a concentration of 1000pg/ml. An opposite action of tri- to tetraCNs than of penta-to heptaCNs on cell proliferation and apoptosis was evident. Tetra PCNs increased cell proliferation, but had no effect on DNA fragmentation nor caspase activity. Fast induction of CYP1A1 protein expression under the influence of lower chlorinated PCNs suggests faster metabolism and a possible stimulatory action of locally formed metabolites on cell proliferation. None of the higher chlorinated PCNs affected cell proliferation but all higher chlorinated PCNs increased caspase-8 activity, and hexa PCNs also increased caspase-9 activity. The rapid activation of the Ah receptor and CYP1A1 protein expression by higher chlorinated PCNs point to their toxicity; however, it is not sufficient for potential carcinogenicity. Action of lower chlorinated naphthalenes metabolites should be explored.

  10. Regulation of Prolactin in Mice with Altered Hypothalamic Melanocortin Activity

    PubMed Central

    Dutia, Roxanne; Kim, Andrea J.; Mosharov, Eugene; Savontaus, Eriika; Chua, Streamson C.; Wardlaw, Sharon L.

    2012-01-01

    This study used two mouse models with genetic manipulation of the melanocortin system to investigate prolactin regulation. Mice with overexpression of the melanocortin receptor (MC-R) agonist, α-melanocyte-stimulating hormone (Tg-MSH) or deletion of the MC-R antagonist agouti-related protein (AgRP KO) were studied. Male Tg-MSH mice had lower blood prolactin levels at baseline (2.9±0.3 vs 4.7±0.7 ng/ml) and after restraint stress(68 ±6.5 vs 117±22 ng/ml) versus WT (p<0.05); however, pituitary prolactin content was not different. Blood prolactin was also decreased in male AgRP KO mice at baseline (4.2±0.5 vs 7.6±1.3 ng/ml) and after stress (60±4.5 vs 86.1±5.7 ng/ml) vs WT (p <0.001). Pituitary prolactin content was lower in male AgRP KO mice (4.3±0.3 vs 6.7±0.5 μg/pituitary, p <0.001) versus WT. No differences in blood or pituitary prolactin levels were observed in female AgRP KO mice versus WT. Hypothalamic dopamine activity was assessed as the potential mechanism responsible for changes in prolactin levels. Hypothalamic tyrosine hydroxylase mRNA was measured in both genetic models versus WT mice and hypothalamic dopamine and 3,4-dihydroxyphenylacetic acid (DOPAC) content were measured in male AgRP KO and WT mice but neither were significantly different. However, these results do not preclude changes in dopamine activity as dopamine turnover was not directly investigated. This is the first study to show that baseline and stress-induced prolactin release and pituitary prolactin content are reduced in mice with genetic alterations of the melanocortin system and suggests that changes in hypothalamic melanocortin activity may be reflected in measurements of serum prolactin levels. PMID:22800691

  11. Chronic neck pain alters muscle activation patterns to sudden movements.

    PubMed

    Boudreau, Shellie A; Falla, Deborah

    2014-06-01

    The aim of this study was to assess the activation of the sternocleidomastoid (SCM) and splenius capitis (SC) muscles in response to unanticipated, full body perturbations in individuals with chronic neck pain (NP) and age-matched healthy controls (HC). Individuals with NP had a history of NP for 8.9 ± 7.8 years, rated the intensity of NP as 4.2 ± 2.0 (score out of 10), and scored 15.3 ± 6.5 on the Neck Disability Index. Participants stood on a moveable platform during which 32 randomized postural perturbations (eight repetitions of four perturbation types: 8 cm forward slide (FS), 8 cm backward slides, 10° forward tilt, and 10° backward tilt) with varying inter-perturbation time intervals were performed over a period of 5 min. Bilateral surface electromyography (EMG) from the SCM and SC was recorded, and the onset time and the average rectified value of the EMG signal was determined for epochs of 100 ms; starting 100 ms prior to and 500 ms after the perturbation onset. Individuals with NP, as compared to HC, demonstrated delayed onset times and reduced EMG amplitude of the SCM and SC muscles in response to all postural perturbations. Such findings were most pronounced following the FS postural perturbation (healthy vs. NP for SCM 83.3 ± 8.0 vs. 86.3 ± 4.4 and SC 75.6 ± 3.5 vs. 89.3 ± 4.2), which was also associated with the greatest change (expressed in % relative to baseline) in EMG amplitude (healthy vs. NP for SCM 206.6 ± 50.4 vs. 115.9 ± 15.7 and SC 83.4 ± 19.2 vs. 69.2 ± 10.9) across all postural perturbations types. Individuals with NP display altered neural control of the neck musculature in response to rapid, unanticipated full body postural perturbations. Although the relative timing of neck musculature activity in individuals with NP appears to be intact, simultaneous co-activation of the neck musculature emerges for unanticipated anterior-posterior postural perturbations.

  12. Regulation of prolactin in mice with altered hypothalamic melanocortin activity.

    PubMed

    Dutia, Roxanne; Kim, Andrea J; Mosharov, Eugene; Savontaus, Eriika; Chua, Streamson C; Wardlaw, Sharon L

    2012-09-01

    This study used two mouse models with genetic manipulation of the melanocortin system to investigate prolactin regulation. Mice with overexpression of the melanocortin receptor (MC-R) agonist, α-melanocyte-stimulating hormone (Tg-MSH) or deletion of the MC-R antagonist agouti-related protein (AgRP KO) were studied. Male Tg-MSH mice had lower blood prolactin levels at baseline (2.9±0.3 vs. 4.7±0.7ng/ml) and after restraint stress (68±6.5 vs. 117±22ng/ml) vs. WT (p<0.05); however, pituitary prolactin content was not different. Blood prolactin was also decreased in male AgRP KO mice at baseline (4.2±0.5 vs. 7.6±1.3ng/ml) and after stress (60±4.5 vs. 86.1±5.7ng/ml) vs. WT (p<0.001). Pituitary prolactin content was lower in male AgRP KO mice (4.3±0.3 vs. 6.7±0.5μg/pituitary, p<0.001) vs. WT. No differences in blood or pituitary prolactin levels were observed in female AgRP KO mice vs. WT. Hypothalamic dopamine activity was assessed as the potential mechanism responsible for changes in prolactin levels. Hypothalamic tyrosine hydroxylase mRNA was measured in both genetic models vs. WT mice and hypothalamic dopamine and 3,4-dihydroxyphenylacetic acid (DOPAC) content were measured in male AgRP KO and WT mice but neither were significantly different. However, these results do not preclude changes in dopamine activity as dopamine turnover was not directly investigated. This is the first study to show that baseline and stress-induced prolactin release and pituitary prolactin content are reduced in mice with genetic alterations of the melanocortin system and suggests that changes in hypothalamic melanocortin activity may be reflected in measurements of serum prolactin levels.

  13. Effects of artificial sweeteners on the AhR- and GR-dependent CYP1A1 expression in primary human hepatocytes and human cancer cells.

    PubMed

    Kamenickova, Alzbeta; Pecova, Michaela; Bachleda, Petr; Dvorak, Zdenek

    2013-12-01

    Food constituents may cause a phenomenon of food-drug interactions. In the current study, we examined the effects of artificial sweeteners (aspartame, acesulfame, cyclamate, saccharin) on the aryl hydrocarbon receptor (AhR) and glucocorticoid receptor (GR)-dependent expression of CYP1A1 in human hepatocytes, hepatic HepG2 and intestinal LS174T cancer cell lines. Sweeteners were tested in concentrations up to those occurring in non-alcoholic beverages. Basal and ligand-inducible AhR- and GR-dependent reporter gene activation in stably transfected HepG2 and HeLa cells, respectively, were not affected by either of the sweeteners tested after 24h of incubation. The expression of CYP1A1 mRNA and protein in primary cultures of human hepatocytes and in LS174T and HepG2 cells was not induced by any of the tested sweeteners. Overall, aspartame, acesulfame, saccharin and cyclamate had no effects on CYP1A1 expression and transcriptional activities of AhR and GR. These data imply the safety of artificial sweeteners in terms of interference with AhR, GR and CYP1A1.

  14. Characterization of the Conformational Alterations, Reduced Anticoagulant Activity, and Enhanced Antiangiogenic Activity of Prelatent Antithrombin*

    PubMed Central

    Richard, Benjamin; Swanson, Richard; Schedin-Weiss, Sophia; Ramirez, Ben; Izaguirre, Gonzalo; Gettins, Peter G. W.; Olson, Steven T.

    2008-01-01

    A conformationally altered prelatent form of antithrombin that possesses both anticoagulant and antiangiogenic activities is produced during the conversion of native to latent antithrombin (Larsson, H., Akerud, P., Nordling, K., Raub-Segall, E., Claesson-Welsh, L., and Björk, I. (2001) J. Biol. Chem. 276, 11996–12002). Here, we show that the previously characterized prelatent antithrombin is a mixture of native antithrombin and a modified, true prelatent antithrombin that are resolvable by heparin-agarose chromatography. Kinetic analyses revealed that prelatent antithrombin is an intermediate in the conversion of native to latent antithrombin whose formation is favored by stabilizing anions of the Hofmeister series. Purified prelatent antithrombin had reduced anticoagulant function compared with native antithrombin, due to a reduced heparin affinity and consequent impaired ability of heparin to either bridge prelatent antithrombin and coagulation proteases in a ternary complex or to induce full conformational activation of the serpin. Significantly, prelatent antithrombin possessed an antiangiogenic activity more potent than that of latent antithrombin, based on the relative abilities of the two forms to inhibit endothelial cell growth. The prelatent form was conformationally altered from native antithrombin as judged from an attenuation of tryptophan fluorescence changes following heparin activation and a reduced thermal stability. The alterations are consistent with the limited structural changes involving strand 1C observed in a prelatent form of plasminogen activator inhibitor-1 (Dupont, D. M., Blouse, G. E., Hansen, M., Mathiasen, L., Kjelgaard, S., Jensen, J. K., Christensen, A., Gils, A., Declerck, P. J., Andreasen, P. A., and Wind, T. (2006) J. Biol. Chem. 281, 36071–36081), since the 1H NMR spectrum, electrophoretic mobility, and proteolytic susceptibility of prelatent antithrombin most resemble those of native rather than those of latent antithrombin

  15. Accurate Orientation Estimation Using AHRS under Conditions of Magnetic Distortion

    PubMed Central

    Yadav, Nagesh; Bleakley, Chris

    2014-01-01

    Low cost, compact attitude heading reference systems (AHRS) are now being used to track human body movements in indoor environments by estimation of the 3D orientation of body segments. In many of these systems, heading estimation is achieved by monitoring the strength of the Earth's magnetic field. However, the Earth's magnetic field can be locally distorted due to the proximity of ferrous and/or magnetic objects. Herein, we propose a novel method for accurate 3D orientation estimation using an AHRS, comprised of an accelerometer, gyroscope and magnetometer, under conditions of magnetic field distortion. The system performs online detection and compensation for magnetic disturbances, due to, for example, the presence of ferrous objects. The magnetic distortions are detected by exploiting variations in magnetic dip angle, relative to the gravity vector, and in magnetic strength. We investigate and show the advantages of using both magnetic strength and magnetic dip angle for detecting the presence of magnetic distortions. The correction method is based on a particle filter, which performs the correction using an adaptive cost function and by adapting the variance during particle resampling, so as to place more emphasis on the results of dead reckoning of the gyroscope measurements and less on the magnetometer readings. The proposed method was tested in an indoor environment in the presence of various magnetic distortions and under various accelerations (up to 3 g). In the experiments, the proposed algorithm achieves <2° static peak-to-peak error and <5° dynamic peak-to-peak error, significantly outperforming previous methods. PMID:25347584

  16. Metabolomics Reveals that Aryl Hydrocarbon Receptor Activation by Environmental Chemicals Induces Systemic Metabolic Dysfunction in Mice

    PubMed Central

    Zhang, Limin; Hatzakis, Emmanuel; Nichols, Robert G.; Hao, Ruixin; Correll, Jared; Smith, Philip B.; Chiaro, Christopher R.; Perdew, Gary H.; Patterson, Andrew D.

    2016-01-01

    Environmental exposure to dioxins and dioxin-like compounds poses a significant health risk for human health. Developing a better understanding of the mechanisms of toxicity through activation of the aryl hydrocarbon receptor (AHR) is likely to improve the reliability of risk assessment. In this study, the AHR-dependent metabolic response of mice exposed to 2,3,7,8-tetrachlorodibenzofuran (TCDF) were assessed using global 1H nuclear magnetic resonance (NMR)-based metabolomics and targeted metabolic profiling of extracts obtained from serum and liver. 1H NMR analyses revealed that TCDF exposure suppressed gluconeogenesis and glycogenolysis, stimulated lipogenesis, and triggered inflammatory gene expression in an Ahr-dependent manner. Targeted analyses using gas chromatography mass spectrometry showed TCDF treatment altered the ratio of unsaturated/saturated fatty acids. Consistent with this observation, an increase in hepatic expression of stearoyl coenzyme A desaturase 1 was also observed. In addition, TCDF exposure resulted in inhibition of de novo fatty acid biosynthesis manifested by down-regulation of acetyl-CoA, malonyl-CoA and palmitoyl-CoA metabolites and related mRNA levels. In contrast, no significant changes in the levels of glucose and lipid were observed in serum and liver obtained from Ahr-null mice following TCDF treatment, thus strongly supporting the important role of the AHR in mediating the metabolic effects seen following TCDF exposure. PMID:26023891

  17. AHR2 knockdown prevents PAH-mediated cardiac toxicity and XRE- and ARE-associated gene induction in zebrafish (Danio rerio)

    SciTech Connect

    Van Tiem, Lindsey A.; Di Giulio, Richard T.

    2011-08-01

    Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental contaminants often present in aquatic systems as complex mixtures. Embryonic fish are sensitive to the developmental toxicity of some PAHs, but the exact mechanisms involved in this toxicity are still unknown. This study explored the role of the aryl hydrocarbon receptor (AHR) in the oxidative stress response of zebrafish to the embryotoxicity of select PAHs. Embryos were exposed to two PAHs, benzo[k]fluoranthene (BkF; a strong AHR agonist) and fluoranthene (FL; a cytochrome P4501A (CYP1A) inhibitor), alone and in combination. CYP1A, CYP1B1, CYP1C1, and redox-responsive genes glutathione s-transferase pi 2 (GSTp2), glutathione peroxidase 1 (GPx1), the glutamate-cysteine ligase catalytic subunit (GCLc), MnSOD and CuZnSOD mRNA expression was examined. CYP1 activity was measured via an in vivo ethoxyresorufin-O-deethlyase (EROD) activity assay, and the area of the pericardium was measured as an index of cardiotoxicity. BkF or FL alone caused no deformities whereas BkF + FL resulted in extreme pericardial effusion. BkF induced CYP activity above controls and co-exposure with FL inhibited this activity. BkF induced expression of all three CYPs, GSTp2, and GCLc. BkF + FL caused greater than additive induction of the three CYPs, GSTp2, GPx1, and GCLc but had no effect on MnSOD or CuZnSOD. AHR2 knockdown protected against the cardiac deformities caused by BkF + FL and significantly inhibited the induction of the CYPs, GSTp2, GPx1, and GCLc after BkF + FL compared to non-injected controls. These results further show the protective role of AHR2 knockdown against cardiotoxic PAHs and the role of AHR2 as a mediator of redox-responsive gene induction. - Research Highlights: > Co-exposure of the PAHs BkF and FL causes cardiotoxicity in zebrafish. > BkF and FL co-exposure upregulates certain XRE- and ARE-associated genes. > AHR2 knockdown prevents the deformities caused by BkF and FL co-exposure. > AHR2

  18. Deciphering Dimerization Modes of PAS Domains: Computational and Experimental Analyses of the AhR:ARNT Complex Reveal New Insights Into the Mechanisms of AhR Transformation

    PubMed Central

    Corrada, Dario; Soshilov, Anatoly A.; Denison, Michael S.

    2016-01-01

    The Aryl hydrocarbon Receptor (AhR) is a transcription factor that mediates the biochemical response to xenobiotics and the toxic effects of a number of environmental contaminants, including dioxins. Recently, endogenous regulatory roles for the AhR in normal physiology and development have also been reported, thus extending the interest in understanding its molecular mechanisms of activation. Since dimerization with the AhR Nuclear Translocator (ARNT) protein, occurring through the Helix-Loop-Helix (HLH) and PER-ARNT-SIM (PAS) domains, is needed to convert the AhR into its transcriptionally active form, deciphering the AhR:ARNT dimerization mode would provide insights into the mechanisms of AhR transformation. Here we present homology models of the murine AhR:ARNT PAS domain dimer developed using recently available X-ray structures of other bHLH-PAS protein dimers. Due to the different reciprocal orientation and interaction surfaces in the different template dimers, two alternative models were developed for both the PAS-A and PAS-B dimers and they were characterized by combining a number of computational evaluations. Both well-established hot spot prediction methods and new approaches to analyze individual residue and residue-pairwise contributions to the MM-GBSA binding free energies were adopted to predict residues critical for dimer stabilization. On this basis, a mutagenesis strategy for both the murine AhR and ARNT proteins was designed and ligand-dependent DNA binding ability of the AhR:ARNT heterodimer mutants was evaluated. While functional analysis disfavored the HIF2α:ARNT heterodimer-based PAS-B model, most mutants derived from the CLOCK:BMAL1-based AhR:ARNT dimer models of both the PAS-A and the PAS-B dramatically decreased the levels of DNA binding, suggesting this latter model as the most suitable for describing AhR:ARNT dimerization. These novel results open new research directions focused at elucidating basic molecular mechanisms underlying the

  19. INSIGHTS FROM AHR AND ARNT GENE KNOCKOUT STUDIES REGARDING RESPONSES TO TCDD AND REGULATION OF NORMAL EMBRYONIC DEVELOPMENT

    EPA Science Inventory

    The aryl hydrocarbon receptor (AhR) and the AhR nuclear translocator (ARNT) are members of the Per-ARNT-Sim (PAS) family of proteins. The AhR binds members of the chemical family that includes dioxins, furans and coplanar polychlorinated biphenyls (PCBs). A ligand-AhR-ARNT comp...

  20. Altered baseline brain activity differentiates regional mechanisms subserving biological and psychological alterations in obese men.

    PubMed

    Zhang, Bin; Tian, Derun; Yu, Chunshui; Li, Meng; Zang, Yufeng; Liu, Yijun; Walter, Martin

    2015-01-01

    Obesity as a chronic disease is a major factor for insulin resistance and Type 2 diabetes, which has become a global health problem. In the present study, we used resting state functional MRI to investigate the amplitude of low frequency fluctuations of spontaneous signal during both hunger and satiety states in 20 lean and 20 obese males. We found that, before food intake, obese men had significantly greater baseline activity in the precuneus and lesser activity in dorsal anterior cingulate cortex (dACC) relative to lean subjects. Furthermore, after food intake, obese males had significantly lesser activity in dACC than lean males. We further found a significant positive correlation between precuneus activation and hunger ratings before food intake, while dACC activity was negatively correlated with plasma insulin levels before and after food intake. These results indicated that both precuneus and dACC may play an important role in eating behavior. While precuneus rather seemed to mediate subjective satiety, dACC levels rather reflected indirect measures of glucose utilization. PMID:26099208

  1. Identification and expression of aryl hydrocarbon receptors (AhR1 and AhR2) provide insight in an evolutionary context regarding sensitivity of white sturgeon (Acipenser transmontanus) to dioxin-like compounds.

    PubMed

    Doering, Jon A; Wiseman, Steve; Beitel, Shawn C; Giesy, John P; Hecker, Markus

    2014-05-01

    Sturgeons are ancient fishes, which are endangered in many parts of the world. Due to their benthic nature and longevity, sturgeon are at great risk of exposure to bioaccumulative contaminants such as dioxin-like compounds (DLCs). Despite their endangered status, little research has been conducted to characterize the relative sensitivity of sturgeons to DLCs. Proper assessment of risk of DLCs posed to these fishes therefore, requires a better understanding of this sensitivity and the factors that are driving it. Adverse effects associated with exposure to DLCs are mediated by the aryl hydrocarbon receptor (AhR). This study identified and characterized two distinct AhRs, AhR1 and AhR2, in white sturgeon (Acipenser transmontanus) for the first time as a first step in studying the relative sensitivities of sturgeons to DLCs. Furthermore, tissue-specific expression of both AhRs under basal conditions and in response to exposure to the model DLC, β-naphthoflavone (βNF), was determined. The sequence of amino acids of AhR1 of white sturgeon had greater similarity to AhRs of tetrapods, including amphibians, birds, and mammals, than to AhR1s of other fishes. The sequence of amino acids in the ligand binding domain of the AhR1 had greater than 80% similarity to AhRs known to bind DLCs and was less similar to AhRs not known to bind DLCs. AhR2 of white sturgeon had greatest similarity to AhR2 of other fishes. Profiles of expression of AhR1 and AhR2 in white sturgeon were distinct from those known in other fishes and appear more similar to profiles observed in birds. Expressions of both AhR1 and AhR2 of white sturgeon were greatest in liver and heart, which are target organs for DLCs. Furthermore, abundances of transcripts of AhR1 and AhR2 in all tissues from white sturgeon were greater than controls (up to 35-fold) following exposure to βNF. Based upon both AhRs having similar abundances of transcript in target organs of DLC toxicity, both AhRs being up-regulated following

  2. Identification and expression of aryl hydrocarbon receptors (AhR1 and AhR2) provide insight in an evolutionary context regarding sensitivity of white sturgeon (Acipenser transmontanus) to dioxin-like compounds.

    PubMed

    Doering, Jon A; Wiseman, Steve; Beitel, Shawn C; Giesy, John P; Hecker, Markus

    2014-05-01

    Sturgeons are ancient fishes, which are endangered in many parts of the world. Due to their benthic nature and longevity, sturgeon are at great risk of exposure to bioaccumulative contaminants such as dioxin-like compounds (DLCs). Despite their endangered status, little research has been conducted to characterize the relative sensitivity of sturgeons to DLCs. Proper assessment of risk of DLCs posed to these fishes therefore, requires a better understanding of this sensitivity and the factors that are driving it. Adverse effects associated with exposure to DLCs are mediated by the aryl hydrocarbon receptor (AhR). This study identified and characterized two distinct AhRs, AhR1 and AhR2, in white sturgeon (Acipenser transmontanus) for the first time as a first step in studying the relative sensitivities of sturgeons to DLCs. Furthermore, tissue-specific expression of both AhRs under basal conditions and in response to exposure to the model DLC, β-naphthoflavone (βNF), was determined. The sequence of amino acids of AhR1 of white sturgeon had greater similarity to AhRs of tetrapods, including amphibians, birds, and mammals, than to AhR1s of other fishes. The sequence of amino acids in the ligand binding domain of the AhR1 had greater than 80% similarity to AhRs known to bind DLCs and was less similar to AhRs not known to bind DLCs. AhR2 of white sturgeon had greatest similarity to AhR2 of other fishes. Profiles of expression of AhR1 and AhR2 in white sturgeon were distinct from those known in other fishes and appear more similar to profiles observed in birds. Expressions of both AhR1 and AhR2 of white sturgeon were greatest in liver and heart, which are target organs for DLCs. Furthermore, abundances of transcripts of AhR1 and AhR2 in all tissues from white sturgeon were greater than controls (up to 35-fold) following exposure to βNF. Based upon both AhRs having similar abundances of transcript in target organs of DLC toxicity, both AhRs being up-regulated following

  3. Fibroblast growth factor (Fgf) 21 is a novel target gene of the aryl hydrocarbon receptor (AhR).

    PubMed

    Cheng, Xingguo; Vispute, Saurabh G; Liu, Jie; Cheng, Christine; Kharitonenkov, Alexei; Klaassen, Curtis D

    2014-07-01

    The toxic effects of dioxins, such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), mainly through activation of the aryl hydrocarbon receptor (AhR) are well documented. Fibroblast growth factor (Fgf) 21 plays critical roles in metabolic adaptation to fasting by increasing lipid oxidation and ketogenesis in the liver. The present study was performed to determine whether activation of the AhR induces Fgf21 expression. In mouse liver, TCDD increased Fgf21 mRNA in both dose- and time-dependent manners. In addition, TCDD markedly increased Fgf21 mRNA expression in cultured mouse and human hepatocytes. Moreover, TCDD increased mRNA (in liver) and protein levels (in both liver and serum) of Fgf21 in wild-type mice, but not in AhR-null mice. Chromatin immunoprecipitation assays showed that TCDD increased AhR protein binding to the Fgf21 promoter (-105/+1 base pair). Fgf21-null mice administered 200μg/kg of TCDD died within 20days, whereas wild-type mice receiving the same treatment were still alive at one month after administration. This indicates that TCDD-induced Fgf21 expression protects against TCDD toxicity. Diethylhexylphthalate (DEHP) pretreatment attenuated TCDD-induced Fgf21 expression in mouse liver and white adipose tissue, which may explain a previous report that DEHP pretreatment decreases TCDD-induced wasting. In conclusion, Fgf21 appears to be a target gene of AhR-signaling pathway in mouse and human liver.

  4. Fibroblast growth factor (Fgf) 21 is a novel target gene of the aryl hydrocarbon receptor (AhR)

    SciTech Connect

    Cheng, Xingguo; Vispute, Saurabh G.; Liu, Jie; Cheng, Christine; Kharitonenkov, Alexei; Klaassen, Curtis D.

    2014-07-01

    The toxic effects of dioxins, such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), mainly through activation of the aryl hydrocarbon receptor (AhR) are well documented. Fibroblast growth factor (Fgf) 21 plays critical roles in metabolic adaptation to fasting by increasing lipid oxidation and ketogenesis in the liver. The present study was performed to determine whether activation of the AhR induces Fgf21 expression. In mouse liver, TCDD increased Fgf21 mRNA in both dose- and time-dependent manners. In addition, TCDD markedly increased Fgf21 mRNA expression in cultured mouse and human hepatocytes. Moreover, TCDD increased mRNA (in liver) and protein levels (in both liver and serum) of Fgf21 in wild-type mice, but not in AhR-null mice. Chromatin immunoprecipitation assays showed that TCDD increased AhR protein binding to the Fgf21 promoter (− 105/+ 1 base pair). Fgf21-null mice administered 200 μg/kg of TCDD died within 20 days, whereas wild-type mice receiving the same treatment were still alive at one month after administration. This indicates that TCDD-induced Fgf21 expression protects against TCDD toxicity. Diethylhexylphthalate (DEHP) pretreatment attenuated TCDD-induced Fgf21 expression in mouse liver and white adipose tissue, which may explain a previous report that DEHP pretreatment decreases TCDD-induced wasting. In conclusion, Fgf21 appears to be a target gene of AhR-signaling pathway in mouse and human liver. - Highlights: • TCDD induced Fgf21 expression at both mRNA and protein levels. • Fgf21 induction by TCDD is AhR-dependent. • DEHP attenuated TCDD-induced Fgf21 expression.

  5. Fibroblast growth factor (Fgf) 21 is a novel target gene of the aryl hydrocarbon receptor (AhR).

    PubMed

    Cheng, Xingguo; Vispute, Saurabh G; Liu, Jie; Cheng, Christine; Kharitonenkov, Alexei; Klaassen, Curtis D

    2014-07-01

    The toxic effects of dioxins, such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), mainly through activation of the aryl hydrocarbon receptor (AhR) are well documented. Fibroblast growth factor (Fgf) 21 plays critical roles in metabolic adaptation to fasting by increasing lipid oxidation and ketogenesis in the liver. The present study was performed to determine whether activation of the AhR induces Fgf21 expression. In mouse liver, TCDD increased Fgf21 mRNA in both dose- and time-dependent manners. In addition, TCDD markedly increased Fgf21 mRNA expression in cultured mouse and human hepatocytes. Moreover, TCDD increased mRNA (in liver) and protein levels (in both liver and serum) of Fgf21 in wild-type mice, but not in AhR-null mice. Chromatin immunoprecipitation assays showed that TCDD increased AhR protein binding to the Fgf21 promoter (-105/+1 base pair). Fgf21-null mice administered 200μg/kg of TCDD died within 20days, whereas wild-type mice receiving the same treatment were still alive at one month after administration. This indicates that TCDD-induced Fgf21 expression protects against TCDD toxicity. Diethylhexylphthalate (DEHP) pretreatment attenuated TCDD-induced Fgf21 expression in mouse liver and white adipose tissue, which may explain a previous report that DEHP pretreatment decreases TCDD-induced wasting. In conclusion, Fgf21 appears to be a target gene of AhR-signaling pathway in mouse and human liver. PMID:24769090

  6. Chronic hyperammonemia alters the circadian rhythms of corticosteroid hormone levels and of motor activity in rats.

    PubMed

    Ahabrach, Hanan; Piedrafita, Blanca; Ayad, Abdelmalik; El Mlili, Nisrin; Errami, Mohammed; Felipo, Vicente; Llansola, Marta

    2010-05-15

    Patients with liver cirrhosis may present hepatic encephalopathy with a wide range of neurological disturbances and alterations in sleep quality and in the sleep-wake circadian rhythm. Hyperammonemia is a main contributor to the neurological alterations in hepatic encephalopathy. We have assessed, in an animal model of chronic hyperammonemia without liver failure, the effects of hyperammonemia per se on the circadian rhythms of motor activity, temperature, and plasma levels of adrenal corticosteroid hormones. Chronic hyperammonemia alters the circadian rhythms of locomotor activity and of cortisol and corticosterone levels in blood. Different types of motor activity are affected differentially. Hyperammonemia significantly alters the rhythm of spontaneous ambulatory activity, reducing strongly ambulatory counts and slightly average velocity during the night (the active phase) but not during the day, resulting in altered circadian rhythms. In contrast, hyperammonemia did not affect wheel running at all, indicating that it affects spontaneous but not voluntary activity. Vertical activity was affected only very slightly, indicating that hyperammonemia does not induce anxiety. Hyperammonemia abolished completely the circadian rhythm of corticosteroid hormones in plasma, completely eliminating the peaks of cortisol and corticosterone present in control rats at the start of the dark period. The data reported show that chronic hyperammonemia, similar to that present in patients with liver cirrhosis, alters the circadian rhythms of corticosteroid hormones and of motor activity. This suggests that hyperammonemia would be a relevant contributor to the alterations in corticosteroid hormones and in circadian rhythms in patients with liver cirrhosis.

  7. Dioxin activation of CYP1A5 promoter/enhancer regions from two avian species, common cormorant (Phalacrocorax carbo) and chicken (Gallus gallus): Association with aryl hydrocarbon receptor 1 and 2 isoforms

    SciTech Connect

    Lee, Jin-Seon; Kim, Eun-Young Iwata, Hisato

    2009-01-01

    The present study focuses on the molecular mechanism and interspecies differences in susceptibility of avian aryl hydrocarbon receptor (AHR)-cytochrome P4501A (CYP1A) signaling pathway. By the cloning of 5'-flanking regions of CYP1A5 gene from common cormorant (Phalacrocorax carbo) and chicken (Gallus gallus), seven putative xenobiotic response elements (XREs) were identified within 2.7 kb upstream region of common cormorant CYP1A5 (ccCYP1A5), and six XREs were found within 0.9 kb of chicken CYP1A5 (ckCYP1A5). Analysis of sequential deletion and mutagenesis of the binding sites in avian CYP1A5 genes by in vitro reporter gene assays revealed that two XREs at -613 bp and -1585 bp in ccCYP1A5, and one XRE at -262 bp in ckCYP1A5 conferred TCDD-responsiveness. The binding of AHR1 with AHR nuclear translocator 1 (ARNT1) to the functional XRE in a TCDD-dependent manner was verified with gel shift assays, suggesting that avian CYP1A5 is induced by TCDD through AHR1/ARNT1 signaling pathway as well as mammalian CYP1A1 but through a distinct pathway from mammalian CYP1A2, an ortholog of the CYP1A5. TCDD-EC{sub 50} for the transcriptional activity in both cormorant AHR1- and AHR2-ccCYP1A5 reporter construct was 10-fold higher than that in chicken AHR1-ckCYP1A5 reporter construct. In contrast, chicken AHR2 showed no TCDD-dependent response. The TCDD-EC{sub 50} for CYP1A5 transactivation was altered by switching AHR1 between the two avian species, irrespective of the species from which the regulatory region of CYP1A5 gene originates. Therefore, the structural difference in AHR, not the CYP1A5 regulatory region may be a major factor to account for the dioxin susceptibility in avian species.

  8. Indole and Tryptophan Metabolism: Endogenous and Dietary Routes to Ah Receptor Activation

    PubMed Central

    Hubbard, Troy D.; Murray, Iain A.

    2015-01-01

    The aryl hydrocarbon receptor (AHR) is a ligand-activated transcription factor recognized for its role in xenobiotic metabolism. The physiologic function of AHR has expanded to include roles in immune regulation, organogenesis, mucosal barrier function, and the cell cycle. These functions are likely dependent upon ligand-mediated activation of the receptor. High-affinity ligands of AHR have been classically defined as xenobiotics, such as polychlorinated biphenyls and dioxins. Identification of endogenous AHR ligands is key to understanding the physiologic functions of this enigmatic receptor. Metabolic pathways targeting the amino acid tryptophan and indole can lead to a myriad of metabolites, some of which are AHR ligands. Many of these ligands exhibit species selective preferential binding to AHR. The discovery of specific tryptophan metabolites as AHR ligands may provide insight concerning where AHR is activated in an organism, such as at the site of inflammation and within the intestinal tract. PMID:26041783

  9. Electroconvulsive shock alters the rat overt rhythms of motor activity and temperature without altering the circadian pacemaker.

    PubMed

    Anglès-Pujolràs, Montserrat; Díez-Noguera, Antoni; Soria, Virginia; Urretavizcaya, Mikel; Menchón, José Manuel; Cambras, Trinitat

    2009-01-01

    The hypothetical relationship between circadian rhythms alterations and depression has prompted studies that examine the resultant effects of various antidepressants. Electroconvulsive therapy (ECT) exerts significant antidepressant effects that have been modelled in the laboratory via the use of electroconvulsive shock (ECS) in rats. However, data on the effects of ECT or ECS vis-à-vis the circadian rhythms remain scarce. Thus, we report here the effects of acute and chronic ECS administration on the temperature and motor activity circadian rhythms of rats. The motor activity and core body temperature of rats were continuously recorded to determine the circadian rhythms. We carried out three experiments. In the first, we analyzed the effects of acute ECS on both the phase and period when applied at different times of the subjective day. In the second and third experiments ECS was nearly daily applied to rats for 3 weeks: respectively, under dim red light, which allows a robust free-running circadian rhythm; and under light-dark cycles of 22 h (T22), a setting that implies dissociation in the circadian system. Acute ECS does not modify the phase or the period of circadian rhythms. Chronic administration of ECS produces an increase in motor activity and temperature, a decrease in the amplitude of circadian rhythms, although the period of the free-running rhythm remains unaffected. In conclusion, while chronic ECS does alter the overt rhythms of motor activity and temperature, it does not modify the functioning of the circadian pacemaker.

  10. Alcohol-induced alterations in dopamine modulation of prefrontal activity.

    PubMed

    Trantham-Davidson, Heather; Chandler, L Judson

    2015-12-01

    Long-term alcohol use leads to persistent cognitive deficits that may be associated with maladaptive changes in the neurocircuitry that mediates executive functions. Impairments caused by these changes can persist well into abstinence and have a negative impact on quality of life and job performance, and can increase the probability of relapse. Many of the changes that affect cognitive function appear to involve dysregulation of the mesocortical dopamine system. This includes changes in dopamine release and alterations in dopamine receptor expression and function in the medial prefrontal cortex (PFC). This review summarizes the cellular effects of acute and chronic ethanol exposure on dopamine release and dopamine receptor function in the PFC with the goal of providing greater understanding of the effects of alcohol-use disorders on the dopamine system and how this relates to deficits in the executive function of the PFC. PMID:26558348

  11. Autogenic training alters cerebral activation patterns in fMRI.

    PubMed

    Schlamann, Marc; Naglatzki, Ryan; de Greiff, Armin; Forsting, Michael; Gizewski, Elke R

    2010-10-01

    Cerebral activation patterns during the first three auto-suggestive phases of autogenic training (AT) were investigated in relation to perceived experiences. Nineteen volunteers trained in AT and 19 controls were studied with fMRI during the first steps of autogenic training. FMRI revealed activation of the left postcentral areas during AT in those with experience in AT, which also correlated with the level of AT experience. Activation of prefrontal and insular cortex was significantly higher in the group with experience in AT while insular activation was correlated with number years of simple relaxation exercises. Specific activation in subjects experienced in AT may represent a training effect. Furthermore, the correlation of insular activation suggests that these subjects are different from untrained subjects in emotional processing or self-awareness.

  12. Heparin alters viral serpin, serp-1, anti-thrombolytic activity to anti-thrombotic activity.

    PubMed

    Li, Xing; Schneider, Heather; Peters, Andrew; Macaulay, Colin; King, Elaine; Sun, Yunming; Liu, Liying; Dai, Erbin; Davids, Jennifer A; McFadden, Grant; Lucas, Alexandra

    2008-01-01

    Serine protease inhibitors (serpins) regulate coagulation and inflammation. Heparin, a glycosaminoglycan, is an important cofactor for modulation of the inhibitory function of mammalian serpins. The secreted myxoma viral serpin, Serp-1 exerts profound anti-inflammatory activity in a wide range of animal models. Serp-1 anti-inflammatory and anti-atherogenic activity is dependent upon inhibition of the uPA / uPA receptor thrombolytic complex. We demonstrate here that heparin binds to Serp-1 and enhances Serp-1 inhibition of thrombin, a human pro-thrombotic serine protease, in vitro, altering inhibitory activity to a more predominant anti-thrombotic activity. Heparin also facilitates the simultaneous thrombin-mediated cleavage of Serp-1 and prevents formation of a serpin-typical SDS-resistant complex, implying mutual neutralization of Serp-1 and thrombin. In a cell-based assay, heparin facilitates Serp-1 reversal of cellular activation by stabilizing cellular membrane fluidity in thrombin-activated monocytes. In conclusion, heparin and other GAGs serve as cofactors enhancing Serp-1 regulation of local thrombotic and inflammatory pathways. PMID:18949070

  13. Alteration of Electro-Cortical Activity in Microgravity

    NASA Astrophysics Data System (ADS)

    Schneider, Stefan; Brummer, Vera; Carnahan, Heather; Askew, Christopher D.; Guardiera, Simon; Struder, Heiko K.

    2008-06-01

    There is growing interest in the effects of weightlessness on central nervous system (CNS) activity. Due to technical and logistical limitations it presently seems impossible to apply imaging techniques as fMRI or PET in weightless environments e.g. on ISS or during parabolic flights. Within this study we evaluated changes in brain cortical activity using low resolution brain electromagnetic tomography (LORETA) during parabolic flights. Results showed a distinct inhibition of right frontal area activity >12Hz during phases of microgravity compared to normal gravity. We conclude that the inhibition of high frequency frontal activity during microgravity may serve as a marker of emotional anxiety and/or indisposition associated with weightlessness. This puts a new light on the debate as to whether cognitive and sensorimotor impairments are attributable to primary physiological effects or secondary psychological effects of a weightless environment.

  14. Alteration of viral infectious behavior by surface active agents.

    PubMed

    Vanden Bossche, G

    1994-06-01

    Phosphate buffered saline (PBS) and wastewater retentate, which had been adjusted to the same level of pH and ionic strength by addition of a concentrated PBS solution, were experimentally seeded with polio- or parvovirus and treated with various concentrations of sodium dodecylsulfate (SDS) and dodecyltrimethylammoniumbromid (DTAB), respectively. Upon subsequent assessment for viral infectivity of the samples in Buffalo green monkey kidney cell cultures, infectivity modulating effects of DTAB in PBS and of SDS in retentate appeared to be largely affected by the electrical charge of the suspended virions. However, if PBS or retentate samples were treated with SDS or DTAB respectively, different isoelectric properties between polio- and parvovirus particles were less likely to affect the detergent concentration required for optimal virus recovery. Moreover, in the presence of soluble organics, optimal virus recovery rates were obtained with much lower detergent concentrations if the samples had been treated with DTAB instead of SDS. Measurement of the effective critical micelle concentration as well as multiangle electrophoretic light scattering (MELS) seemed to provide a simple approach to monitoring colloidal stability of multicomponent viral particle (VP) suspensions upon the addition of ionic detergents. By measuring zeta potential distribution, MELS offers additional information about alterations to electrical viral surface properties. Since the behavior of VPs is well known to largely depend upon their electrical characteristics within the environment in which they exist, there is substantial evidence that MELS can provide valuable guidelines in studying optimal detergent-treatment conditions for virus recovery from aqueous suspensions.

  15. Amygdala kindling alters protein kinase C activity in dentate gyrus.

    PubMed

    Chen, S J; Desai, M A; Klann, E; Winder, D G; Sweatt, J D; Conn, P J

    1992-11-01

    Kindling is a use-dependent form of synaptic plasticity and a widely used model of epilepsy. Although kindling has been widely studied, the molecular mechanisms underlying induction of this phenomenon are not well understood. We determined the effect of amygdala kindling on protein kinase C (PKC) activity in various regions of rat brain. Kindling stimulation markedly elevated basal (Ca(2+)-independent) and Ca(2+)-stimulated phosphorylation of an endogenous PKC substrate (which we have termed P17) in homogenates of dentate gyrus, assayed 2 h after kindling stimulation. The increase in P17 phosphorylation appeared to be due at least in part to persistent PKC activation, as basal PKC activity assayed in vitro using an exogenous peptide substrate was increased in kindled dentate gyrus 2 h after the last kindling stimulation. A similar increase in basal PKC activity was observed in dentate gyrus 2 h after the first kindling stimulation. These results document a kindling-associated persistent PKC activation and suggest that the increased activity of PKC could play a role in the induction of the kindling effect.

  16. Genome-wide RNAi high-throughput screen identifies proteins necessary for the AHR-dependent induction of CYP1A1 by 2,3,7,8-tetrachlorodibenzo-p-dioxin.

    PubMed

    Solaimani, Parrisa; Damoiseaux, Robert; Hankinson, Oliver

    2013-11-01

    The aryl hydrocarbon receptor (AHR) has a plethora of physiological roles, and upon dysregulation, carcinogenesis can occur. One target gene of AHR encodes the xenobiotic and drug-metabolizing enzyme CYP1A1, which is inducible by the environmental contaminant 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) via the AHR. An siRNA library targeted against over 5600 gene candidates in the druggable genome was used to transfect mouse Hepa-1 cells, which were then treated with TCDD, and subsequently assayed for CYP1A1-dependent ethoxyresorufin-o-deethylase (EROD) activity. Following redundant siRNA activity (RSA) statistical analysis, we identified 93 hits that reduced EROD activity with a p value ≤ .005 and substantiated 39 of these as positive hits in a secondary screening using endoribonuclease-prepared siRNAs (esiRNAs). Twelve of the corresponding gene products were subsequently confirmed to be necessary for the induction of CYP1A1 messenger RNA by TCDD. None of the candidates were deficient in aryl hydrocarbon nuclear translocator expression. However 6 gene products including UBE2i, RAB40C, CRYGD, DCTN4, RBM5, and RAD50 are required for the expression of AHR as well as for induction of CYP1A1. We also found 2 gene products, ARMC8 and TCF20, to be required for the induction of CYP1A1, but our data are ambiguous as to whether they are required for the expression of AHR. In contrast, SIN3A, PDC, TMEM5, and CD9 are not required for AHR expression but are required for the induction of CYP1A1, implicating a direct role in Cyp1a1 transcription. Our methods, although applied to Cyp1a1, could be modified for identifying proteins that regulate other inducible genes. PMID:23997114

  17. Genome-Wide RNAi High-Throughput Screen Identifies Proteins Necessary for the AHR-Dependent Induction of CYP1A1 by 2,3,7,8-Tetrachlorodibenzo-p-dioxin

    PubMed Central

    Hankinson, Oliver

    2013-01-01

    The aryl hydrocarbon receptor (AHR) has a plethora of physiological roles, and upon dysregulation, carcinogenesis can occur. One target gene of AHR encodes the xenobiotic and drug-metabolizing enzyme CYP1A1, which is inducible by the environmental contaminant 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) via the AHR. An siRNA library targeted against over 5600 gene candidates in the druggable genome was used to transfect mouse Hepa-1 cells, which were then treated with TCDD, and subsequently assayed for CYP1A1-dependent ethoxyresorufin-o-deethylase (EROD) activity. Following redundant siRNA activity (RSA) statistical analysis, we identified 93 hits that reduced EROD activity with a p value ≤ .005 and substantiated 39 of these as positive hits in a secondary screening using endoribonuclease-prepared siRNAs (esiRNAs). Twelve of the corresponding gene products were subsequently confirmed to be necessary for the induction of CYP1A1 messenger RNA by TCDD. None of the candidates were deficient in aryl hydrocarbon nuclear translocator expression. However 6 gene products including UBE2i, RAB40C, CRYGD, DCTN4, RBM5, and RAD50 are required for the expression of AHR as well as for induction of CYP1A1. We also found 2 gene products, ARMC8 and TCF20, to be required for the induction of CYP1A1, but our data are ambiguous as to whether they are required for the expression of AHR. In contrast, SIN3A, PDC, TMEM5, and CD9 are not required for AHR expression but are required for the induction of CYP1A1, implicating a direct role in Cyp1a1 transcription. Our methods, although applied to Cyp1a1, could be modified for identifying proteins that regulate other inducible genes. PMID:23997114

  18. Acute Neuroactive Drug Exposures alter Locomotor Activity in Larval Zebrafish

    EPA Science Inventory

    As part of the development of a rapid in vivo screen for prioritization of toxic chemicals, we have begun to characterize the locomotor activity of zebrafish (Danio rerio) larvae by assessing the acute effects of prototypic drugs that act on the central nervous system. Initially,...

  19. Acute neuroactive drug exposures alter locomotor activity in larval zebrafish

    EPA Science Inventory

    In an effort to develop a rapid in vivo screen for EPA's prioritization of toxic chemicals, we are characterizing the locomotor activity of zebrafish (Danio rerio) larvae after exposure to prototypic drugs that act on the central nervous system. MPTP (1-methyl-4phenyl- 1 ,2,3,6-...

  20. Altered Error-Related Activity in Patients with Schizophrenia

    ERIC Educational Resources Information Center

    Koch, Kathrin; Wagner, Gerd; Schultz, Christoph; Schachtzabel, Claudia; Nenadic, Igor; Axer, Martina; Reichenbach, Jurgen R.; Sauer, Heinrich; Schlosser, Ralf G. M.

    2009-01-01

    Deficits in working memory (WM) and executive cognitive control are core features of schizophrenia. However, findings regarding functional activation strengths are heterogeneous, partly due to differences in task demands and behavioral performance. Previous investigators proposed integrating these heterogeneous findings into a comprehensive model…

  1. Repression and activation by multiprotein complexes that alter chromatin structure.

    PubMed

    Kingston, R E; Bunker, C A; Imbalzano, A N

    1996-04-15

    Recent studies have provided strong evidence that macromolecular complexes are used in the cell to remodel chromatin structure during activation and to create an inaccessible structure during repression, Although there is not yet any rigorous demonstration that modification of chromatin structure plays a direct, causal role in either activation or repression, there is sufficient smoke to indicate the presence of a blazing inferno nearby. It is clear that complexes that remodel chromatin are tractable in vitro; hopefully this will allow the establishment of systems that provide a direct analysis of the role that remodeling might play in activation. These studies indicate that establishment of functional systems to corroborate the elegant genetic studies on repression might also be tractable. As the mechanistic effects of these complexes are sorted out, it will become important to understand how the complexes are regulated. In many of the instances discussed above, the genes whose products make up these complexes were identified in genetic screens for effects on developmental processes. This implies a regulation of the activity of these complexes in response to developmental cues and further implies that the work to fully understand these complexes will occupy a generation of scientists.

  2. Silver and Gold Nanoparticles Alter Cathepsin Activity In vitro

    NASA Astrophysics Data System (ADS)

    Speshock, Janice L.; Braydich-Stolle, Laura K.; Szymanski, Eric R.; Hussain, Saber M.

    2011-12-01

    Nanomaterials are being incorporated into many biological applications for use as therapeutics, sensors, or labels. Silver nanomaterials are being utilized for biological implants and wound dressings as an antiviral material, whereas gold nanomaterials are being used as biological labels or sensors due to their surface properties and biocompatibility. Cytotoxicity data of these materials are becoming more prevalent; however, little research has been performed to understand how the introduction of these materials into cells affects cellular processes. Here, we demonstrate the impact that silver and gold nanoparticles have on cathepsin activity in vitro. Cathepsins are important cellular proteases that are imperative for proper immune system function. We have selected to examine gold and silver nanoparticles due to the increased use of these materials in biological applications. This manuscript depicts how both of these types of nanomaterials affect cathepsin activity, which could impact the host's immune system and its ability to respond to pathogens. Cathepsin B activity decreases in a dose-dependent manner with all nanoparticles tested. Alternatively, the impact of nanoparticles on cathepsin L activity depends greatly on the type and size of the material.

  3. Compounds from Silicones Alter Enzyme Activity in Curing Barnacle Glue and Model Enzymes

    PubMed Central

    Rittschof, Daniel; Orihuela, Beatriz; Harder, Tilmann; Stafslien, Shane; Chisholm, Bret; Dickinson, Gary H.

    2011-01-01

    Background Attachment strength of fouling organisms on silicone coatings is low. We hypothesized that low attachment strength on silicones is, in part, due to the interaction of surface available components with natural glues. Components could alter curing of glues through bulk changes or specifically through altered enzyme activity. Methodology/Principal Findings GC-MS analysis of silicone coatings showed surface-available siloxanes when the coatings were gently rubbed with a cotton swab for 15 seconds or given a 30 second rinse with methanol. Mixtures of compounds were found on 2 commercial and 8 model silicone coatings. The hypothesis that silicone components alter glue curing enzymes was tested with curing barnacle glue and with commercial enzymes. In our model, barnacle glue curing involves trypsin-like serine protease(s), which activate enzymes and structural proteins, and a transglutaminase which cross-links glue proteins. Transglutaminase activity was significantly altered upon exposure of curing glue from individual barnacles to silicone eluates. Activity of purified trypsin and, to a greater extent, transglutaminase was significantly altered by relevant concentrations of silicone polymer constituents. Conclusions/Significance Surface-associated silicone compounds can disrupt glue curing and alter enzyme properties. Altered curing of natural glues has potential in fouling management. PMID:21379573

  4. Alterations of autonomic nervous activity in recurrence of variant angina

    PubMed Central

    Takusagawa, M; Komori, S; Umetani, K; Ishihara, T; Sawanobori, T; Kohno, I; Sano, S; Yin, D; Ijiri, H; Tamura, K

    1999-01-01

    OBJECTIVE—To investigate whether autonomic nervous activity is involved in the recurrence of spontaneous coronary spasm in variant angina.
DESIGN—Retrospective analysis.
SETTING—Cardiology department of a university hospital.
PATIENTS—18 patients with variant angina were divided into single attack group (SA; nine patients) and multiple attack group (MA; nine patients) according to the frequency of ischaemic episodes with ST segment elevation during 24 hour Holter monitoring.
METHODS—Heart rate variability indices were calculated using MemCalc method, which is a combination of the maximum entropy method for spectral analysis and the non-linear least squares method for fitting analysis, at 30 second intervals for 30 second periods, from 40 minutes before the attack to 30 minutes after the attack. High frequency (HF; 0.04-0.15 Hz) was defined as a marker of parasympathetic activity, and the ratio of low frequency (LF; 0.15-0.40 Hz) to high frequency (LF/HF) as an indicator of sympathetic activity. The averaged value during the 40 to 30 minute period before an attack was defined as the baseline.
RESULTS—Compared with baseline, the HF component decreased in both groups at two minutes before the attack (p < 0.01), and the LF/HF ratio decreased at three minutes before the attack (p < 0.01). The baseline LF/HF was lower in the MA group than in the SA group (p < 0.01).
CONCLUSIONS—A reduction of sympathetic activity may play a key role in determining the recurrence of transient ischaemic events caused by spontaneous coronary spasm in patients with variant angina.


Keywords: sympathetic activity; recurrence of coronary spasm; MemCalc method; variant angina PMID:10377313

  5. Altered brain activity during pain processing in fibromyalgia.

    PubMed

    Burgmer, Markus; Pogatzki-Zahn, Esther; Gaubitz, Markus; Wessoleck, Erik; Heuft, Gereon; Pfleiderer, Bettina

    2009-01-15

    Fibromyalgia syndrome (FMS) is characterized by widespread pain. Studies with functional neuroimaging support the hypothesis of central pain augmentation in FMS. We tested this in our study with a novel paradigm of tonic pain induced by a single stimulus. Tonic pain, in contrast to phasic pain, seems to be a more appropriate experimental approach to study adaptive mechanisms of pain processing in FMS. We hypothesized that brain areas related to the "medial" pain system and the amygdalae will present different activation in patients compared to healthy subjects. An fMRI-block design before, during and after an incision was made in patients with FMS and in healthy controls. Acute pain caused by the incision was measured during the course of the experiment. A 2 factorial model of BOLD-signal changes was designed to explore significant differences of brain activation between both groups during the pain stimulus. Additionally the first Eigenvariates in those areas which show an interaction between both factors were determined over the time course of pain stimulation. Differences of activation in the fronto-cingulate cortex, the supplemental motor areas, and the thalamus were found between both groups with distinct differences in BOLD-signals changes over the time course of pain stimulation, even during anticipation of pain. Our results support the hypothesis that central mechanisms of pain processing in the medial pain system, favourable cognitive/affective factors even during the anticipation of pain, may play an important role for pain processing in patients with FMS. PMID:18848998

  6. The speed of lexical activation is altered in Parkinson's disease.

    PubMed

    Angwin, Anthony J; Chenery, Helen J; Copland, David A; Murdoch, Bruce E; Silburn, Peter A

    2007-01-01

    Disturbed comprehension of complex noncanonical sentences in Parkinson's disease (PD) has been linked to dopamine depletion and delayed lexical retrieval. The aim of the present study was to replicate findings of delayed lexical activation in PD patients with noncanonical sentence processing difficulties, and investigate the influence of dopamine depletion on these changes to lexical access. In the first experiment, 20 patients with PD (tested whilst 'on' dopaminergic medication) and 23 controls participated in a list priming experiment. In this paradigm, stimuli are presented as a continuous list of words/nonwords, and semantic priming effects were measured across inter-stimulus intervals (ISIs) of 500 ms, 1000 ms and 1500 ms, with data analyzed using multivariate analyses of variance. The results revealed longer delays in lexical activation for PD patients with poor comprehension of noncanonical sentences, suggesting that the speed of lexical access may be compromised in PD, and that this feature may contribute to certain sentencecomprehension difficulties. In the second experiment, 7 patients with PD who participated in the first experiment, performed the same lexical decision task while 'off' their dopaminergic medication. Semantic priming effects were measured across ISIs of 500 ms and 1500 ms. Within group comparisons revealed a different pattern of semantic priming for the PD patients when 'on' compared to 'off' medication, providing further support for a dopaminergic influence on the speed of information processing and lexical activation.

  7. Postnatal foraging demands alter adrenocortical activity and psychosocial development.

    PubMed

    Lyons, D M; Kim, S; Schatzberg, A F; Levine, S

    1998-05-01

    Mother squirrel monkeys stop carrying infants at earlier ages in high-demand (HD) conditions where food is difficult to find relative to low-demand (LD) conditions. To characterize these transitions in psychosocial development, from 10- to 21-weeks postpartum we collected measures of behavior, adrenocortical activity, and social transactions coded for initiator (mother or infant), goal (make-contact or break-contact), and outcome (success or failure). Make-contact attempts were most often initiated by HD infants, but mothers often opposed these attempts and less than 50% were successful. Break-contact attempts were most often initiated by LD infants, but mothers often opposed these attempts and fewer LD than HD infant break-contact attempts were successful. Plasma levels of cortisol were significantly higher in HD than LD mothers, but differences in adrenocortical activity were less consistent in their infants. HD and LD infants also spent similar amounts of time nursing on their mothers and feeding on solid foods. By rescheduling some transitions in development (carry-->self-transport), and not others (nursing-->self-feeding), mothers may have partially protected infants from the immediate impact of an otherwise stressful foraging task. PMID:9589217

  8. Alterations in electrodermal activity and cardiac parasympathetic tone during hypnosis.

    PubMed

    Kekecs, Zoltán; Szekely, Anna; Varga, Katalin

    2016-02-01

    Exploring autonomic nervous system (ANS) changes during hypnosis is critical for understanding the nature and extent of the hypnotic phenomenon and for identifying the mechanisms underlying the effects of hypnosis in different medical conditions. To assess ANS changes during hypnosis, electrodermal activity and pulse rate variability (PRV) were measured in 121 young adults. Participants either received hypnotic induction (hypnosis condition) or listened to music (control condition), and both groups were exposed to test suggestions. Blocks of silence and experimental sound stimuli were presented at baseline, after induction, and after de-induction. Skin conductance level (SCL) and high frequency (HF) power of PRV measured at each phase were compared between groups. Hypnosis decreased SCL compared to the control condition; however, there were no group differences in HF power. Furthermore, hypnotic suggestibility did not moderate ANS changes in the hypnosis group. These findings indicate that hypnosis reduces tonic sympathetic nervous system activity, which might explain why hypnosis is effective in the treatment of disorders with strong sympathetic nervous system involvement, such as rheumatoid arthritis, hot flashes, hypertension, and chronic pain. Further studies with different control conditions are required to examine the specificity of the sympathetic effects of hypnosis.

  9. Microglia mechanics: immune activation alters traction forces and durotaxis

    PubMed Central

    Bollmann, Lars; Koser, David E.; Shahapure, Rajesh; Gautier, Hélène O. B.; Holzapfel, Gerhard A.; Scarcelli, Giuliano; Gather, Malte C.; Ulbricht, Elke; Franze, Kristian

    2015-01-01

    Microglial cells are key players in the primary immune response of the central nervous system. They are highly active and motile cells that chemically and mechanically interact with their environment. While the impact of chemical signaling on microglia function has been studied in much detail, the current understanding of mechanical signaling is very limited. When cultured on compliant substrates, primary microglial cells adapted their spread area, morphology, and actin cytoskeleton to the stiffness of their environment. Traction force microscopy revealed that forces exerted by microglia increase with substrate stiffness until reaching a plateau at a shear modulus of ~5 kPa. When cultured on substrates incorporating stiffness gradients, microglia preferentially migrated toward stiffer regions, a process termed durotaxis. Lipopolysaccharide-induced immune-activation of microglia led to changes in traction forces, increased migration velocities and an amplification of durotaxis. We finally developed a mathematical model connecting traction forces with the durotactic behavior of migrating microglial cells. Our results demonstrate that microglia are susceptible to mechanical signals, which could be important during central nervous system development and pathologies. Stiffness gradients in tissue surrounding neural implants such as electrodes, for example, could mechanically attract microglial cells, thus facilitating foreign body reactions detrimental to electrode functioning. PMID:26441534

  10. Alterations in electrodermal activity and cardiac parasympathetic tone during hypnosis.

    PubMed

    Kekecs, Zoltán; Szekely, Anna; Varga, Katalin

    2016-02-01

    Exploring autonomic nervous system (ANS) changes during hypnosis is critical for understanding the nature and extent of the hypnotic phenomenon and for identifying the mechanisms underlying the effects of hypnosis in different medical conditions. To assess ANS changes during hypnosis, electrodermal activity and pulse rate variability (PRV) were measured in 121 young adults. Participants either received hypnotic induction (hypnosis condition) or listened to music (control condition), and both groups were exposed to test suggestions. Blocks of silence and experimental sound stimuli were presented at baseline, after induction, and after de-induction. Skin conductance level (SCL) and high frequency (HF) power of PRV measured at each phase were compared between groups. Hypnosis decreased SCL compared to the control condition; however, there were no group differences in HF power. Furthermore, hypnotic suggestibility did not moderate ANS changes in the hypnosis group. These findings indicate that hypnosis reduces tonic sympathetic nervous system activity, which might explain why hypnosis is effective in the treatment of disorders with strong sympathetic nervous system involvement, such as rheumatoid arthritis, hot flashes, hypertension, and chronic pain. Further studies with different control conditions are required to examine the specificity of the sympathetic effects of hypnosis. PMID:26488759

  11. Microglia mechanics: immune activation alters traction forces and durotaxis.

    PubMed

    Bollmann, Lars; Koser, David E; Shahapure, Rajesh; Gautier, Hélène O B; Holzapfel, Gerhard A; Scarcelli, Giuliano; Gather, Malte C; Ulbricht, Elke; Franze, Kristian

    2015-01-01

    Microglial cells are key players in the primary immune response of the central nervous system. They are highly active and motile cells that chemically and mechanically interact with their environment. While the impact of chemical signaling on microglia function has been studied in much detail, the current understanding of mechanical signaling is very limited. When cultured on compliant substrates, primary microglial cells adapted their spread area, morphology, and actin cytoskeleton to the stiffness of their environment. Traction force microscopy revealed that forces exerted by microglia increase with substrate stiffness until reaching a plateau at a shear modulus of ~5 kPa. When cultured on substrates incorporating stiffness gradients, microglia preferentially migrated toward stiffer regions, a process termed durotaxis. Lipopolysaccharide-induced immune-activation of microglia led to changes in traction forces, increased migration velocities and an amplification of durotaxis. We finally developed a mathematical model connecting traction forces with the durotactic behavior of migrating microglial cells. Our results demonstrate that microglia are susceptible to mechanical signals, which could be important during central nervous system development and pathologies. Stiffness gradients in tissue surrounding neural implants such as electrodes, for example, could mechanically attract microglial cells, thus facilitating foreign body reactions detrimental to electrode functioning. PMID:26441534

  12. Regulation of zebrafish CYP3A65 transcription by AHR2

    SciTech Connect

    Chang, Chin-Teng; Chung, Hsin-Yu; Su, Hsiao-Ting; Tseng, Hua-Pin; Tzou, Wen-Shyong; Hu, Chin-Hwa

    2013-07-15

    CYP3A proteins are the most abundant CYPs in the liver and intestines, and they play a pivotal role in drug metabolism. In mammals, CYP3A genes are induced by various xenobiotics through processes mediated by PXR. We previously identified zebrafish CYP3A65 as a CYP3A ortholog that is constitutively expressed in gastrointestinal tissues, and is upregulated by treatment with dexamethasone, rifampicin or tetrachlorodibenzo-p-dioxin (TCDD). However, the underlying mechanism of TCDD-mediated CYP3A65 transcription is unclear. Here we generated two transgenic zebrafish, Tg(CYP3A65S:EGFP) and Tg(CYP3A65L:EGFP), which contain 2.1 and 5.4 kb 5′ flanking sequences, respectively, of the CYP3A65 gene upstream of EGFP. Both transgenic lines express EGFP in larval gastrointestinal tissues in a pattern similar to that of the endogenous CYP3A65 gene. Moreover, EGFP expression can be significantly induced by TCDD exposure during the larval stage. In addition, EGFP expression can be stimulated by kynurenine, a putative AHR ligand produced during tryptophan metabolism. AHRE elements in the upstream regulatory region of the CYP3A65 gene are indispensible for basal and TCDD-induced transcription. Furthermore, the AHR2 DNA and ligand-binding domains are required to mediate effective CYP3A65 transcription. AHRE sequences are present in the promoters of many teleost CYP3 genes, but not of mammalian CYP3 genes, suggesting that AHR/AHR2-mediated transcription is likely a common regulatory mechanism for teleost CYP3 genes. It may also reflect the different environments that terrestrial and aquatic organisms encounter. - Highlights: • Tg(CYP3A65:EGFP) and CYP3A65 exhibits identical expression pattern. • CYP3A65 can be significantly induced by TCDD or kynurenine. • The AHRE elements are required to mediate CYP3A65 transcription. • The AHR2 DNA and ligand-binding domains are required for CYP3A65 transcription. • AHRE elements are present in many teleost CYP3 genes, but not in

  13. AhR expression and polymorphisms are associated with risk of coronary arterial disease in Chinese population

    PubMed Central

    Huang, Shian; Shui, Xiaorong; He, Yuan; Xue, Yiqiang; Li, Jianwen; Li, Guoming; Lei, Wei; Chen, Can

    2015-01-01

    The aryl hydrocarbon receptor (AhR) mediates the control of environmental toxicity, and modulates the development and pathogenesis of the cardiovascular system. However, little is known about the role of AhR in coronary arterial disease (CAD) susceptibility. We therefore conducted a case-control study in a Chinese population, and assessed the potential association between AhR variants and CAD susceptibility. Compared with the controls, circulating AhR expression was found to be significantly increased in patients with CAD and its subtypes including ST-segment and non-ST-segment elevation myocardial infarction, and stable and unstable angina pectoris. Receiver operating characteristic (ROC) analysis to evaluate the effect of AhR on CAD progression showed it to be a potent biomarker for CAD. Genotype frequencies of AhR rs2066853 differed significantly between CAD and control subjects, while smoking and hyperlipidemia markedly promoted CAD risk relative to the AhR polymorphism. Moreover, a significant difference in AhR variant distribution was observed between the four CAD subtypes with different severities. The expression level and functional polymorphisms of circulating AhR may affect the susceptibility and progression of CAD in Chinese populations. This provides a novel view of the etiology and epidemiology of CAD, and will contribute to the diagnosis and therapy of this severe disease. PMID:25620626

  14. Genetic variation at aryl hydrocarbon receptor (AHR) loci in populations of Atlantic killifish (Fundulus heteroclitus) inhabiting polluted and reference habitats

    PubMed Central

    2014-01-01

    Background The non-migratory killifish Fundulus heteroclitus inhabits clean and polluted environments interspersed throughout its range along the Atlantic coast of North America. Several populations of this species have successfully adapted to environments contaminated with toxic aromatic hydrocarbon pollutants such as polychlorinated biphenyls (PCBs). Previous studies suggest that the mechanism of resistance to these and other “dioxin-like compounds” (DLCs) may involve reduced signaling through the aryl hydrocarbon receptor (AHR) pathway. Here we investigated gene diversity and evidence for positive selection at three AHR-related loci (AHR1, AHR2, AHRR) in F. heteroclitus by comparing alleles from seven locations ranging over 600 km along the northeastern US, including extremely polluted and reference estuaries, with a focus on New Bedford Harbor (MA, USA), a PCB Superfund site, and nearby reference sites. Results We identified 98 single nucleotide polymorphisms within three AHR-related loci among all populations, including synonymous and nonsynonymous substitutions. Haplotype distributions were spatially segregated and F-statistics suggested strong population genetic structure at these loci, consistent with previous studies showing strong population genetic structure at other F. heteroclitus loci. Genetic diversity at these three loci was not significantly different in contaminated sites as compared to reference sites. However, for AHR2 the New Bedford Harbor population had significant FST values in comparison to the nearest reference populations. Tests for positive selection revealed ten nonsynonymous polymorphisms in AHR1 and four in AHR2. Four nonsynonymous SNPs in AHR1 and three in AHR2 showed large differences in base frequency between New Bedford Harbor and its reference site. Tests for isolation-by-distance revealed evidence for non-neutral change at the AHR2 locus. Conclusion Together, these data suggest that F. heteroclitus populations in reference

  15. Altered behavior in spotted hyenas associated with increased human activity

    USGS Publications Warehouse

    Boydston, Erin E.; Kapheim, Karen M.; Watts, Heather E.; Szykman, Micaela; Holekamp, Kay E.

    2003-01-01

    To investigate how anthropogenic activity might affect large carnivores, we studied the behaviour of spotted hyenas (Crocuta crocuta) during two time periods. From 1996 to 1998, we documented the ecological correlates of space utilization patterns exhibited by adult female hyenas defending a territory at the edge of a wildlife reserve in Kenya. Hyenas preferred areas near dense vegetation but appeared to avoid areas containing the greatest abundance of prey, perhaps because these were also the areas of most intensive livestock grazing. We then compared hyena behaviour observed in 1996–98 with that observed several years earlier and found many differences. Female hyenas in 1996–98 were found farther from dens, but closer to dense vegetation and to the edges of their territory, than in 1988–90. Recent females also had larger home ranges, travelled farther between consecutive sightings, and were more nocturnal than in 1988–90. Finally, hyenas occurred in smaller groups in 1996–98 than in 1988–90. We also found several changes in hyena demography between periods. We next attempted to explain differences observed between time periods by testing predictions of hypotheses invoking prey abundance, climate, interactions with lions, tourism and livestock grazing. Our data were consistent with the hypothesis that increased reliance on the reserve for livestock grazing was responsible for observed changes. That behavioural changes were not associated with decreased hyena population density suggests the behavioural plasticity typical of this species may protect it from extinction.

  16. Altered behaviour in spotted hyenas associated with increased human activity

    USGS Publications Warehouse

    Boydston, E.E.; Kapheim, K.M.; Watts, H.E.; Szykman, M.; Holekamp, K.E.

    2003-01-01

    To investigate how anthropogenic activity might affect large carnivores, we studied the behaviour of spotted hyenas (Crocuta crocuta) during two time periods. From 1996 to 1998, we documented the ecological correlates of space utilization patterns exhibited by adult female hyenas defending a territory at the edge of a wildlife reserve in Kenya. Hyenas preferred areas near dense vegetation but appeared to avoid areas containing the greatest abundance of prey, perhaps because these were also the areas of most intensive livestock grazing. We then compared hyena behaviour observed in 1996-98 with that observed several years earlier and found many differences. Female hyenas in 1996-98 were found farther from dens, but closer to dense vegetation and to the edges of their territory, than in 1988-90. Recent females also had larger home ranges, travelled farther between consecutive sightings, and were more nocturnal than in 1988-90. Finally, hyenas occurred in smaller groups in 1996-98 than in 1988-90. We also found several changes in hyena demography between periods. We next attempted to explain differences observed between time periods by testing predictions of hypotheses invoking prey abundance, climate, interactions with lions, tourism and livestock grazing. Our data were consistent with the hypothesis that increased reliance on the reserve for livestock grazing was responsible for observed changes. That behavioural changes were not associated with decreased hyena population density suggests the behavioural plasticity typical of this species may protect it from extinction. ?? 2003 The Zoological Society of London.

  17. Evening physical activity alters wrist temperature circadian rhythmicity

    PubMed Central

    Rubio-Sastre, Patricia; Gómez-Abellán, Purificación; Martinez-Nicolas, Antonio; Ordovás, José María; Madrid, Juan Antonio; Garaulet, Marta

    2015-01-01

    The adequate time to perform physical activity (PA) to maintain optimal circadian system health has not been defined. We studied the influence of morning and evening PA on circadian rhythmicity in 16 women with wrist temperature (WT). Participants performed controlled PA (45 min continuous-running) during 7 days in the morning (MPA) and evening (EPA) and results were compared with a no-exercise-week (C). EPA was characterized by a lower amplitude (evening: 0.028 ± 0.01 °C versus control: 0.038 ± 0.016 °C; p<0.05) less pronounced second-harmonic (power) (evening: 0.41 ± 0.47 versus morning: 1.04 ± 0.59); and achrophase delay (evening: 06:35 ± 02:14 h versus morning: 04:51 ± 01:11 h; p>0.05) as compared to MPA and C. Performing PA in the late evening might not be as beneficial as in the morning. PMID:24517176

  18. Altered host behaviour and brain serotonergic activity caused by acanthocephalans: evidence for specificity

    PubMed Central

    Tain, Luke; Perrot-Minnot, Marie-Jeanne; Cézilly, Frank

    2006-01-01

    Manipulative parasites can alter the phenotype of intermediate hosts in various ways. However, it is unclear whether such changes are just by-products of infection or adaptive and enhance transmission to the final host. Here, we show that the alteration of serotonergic activity is functionally linked to the alteration of specific behaviour in the amphipod Gammarus pulex infected with acanthocephalan parasites. Pomphorhynchus laevis and, to a lesser extent, Pomphorhynchus tereticollis altered phototactism, but not geotactism, in G. pulex, whereas the reverse was true for Polymorphus minutus. Serotonin (5-hydroxytryptamine, 5-HT) injected to uninfected G. pulex mimicked the altered phototactism, but had no effect on geotactism. Photophilic G. pulex infected with P. laevis or P. tereticollis showed a 40% increase in brain 5-HT immunoreactivity compared to photophobic, uninfected individuals. In contrast, brain 5-HT immunoreactivity did not differ between P. minutus-infected and uninfected G. pulex. Finally, brain 5-HT immunoreactivity differed significantly among P. tereticollis-infected individuals in accordance with their degree of manipulation. Our results demonstrate that altered 5-HT activity is not the mere consequence of infection by acanthocephalans but is specifically linked to the disruption of host photophobic behaviour, whereas the alteration of other behaviours such as geotactism may rely on distinct physiological routes. PMID:17015346

  19. Preferential induction of the AhR gene battery in HepaRG cells after a single or repeated exposure to heterocyclic aromatic amines

    SciTech Connect

    Dumont, Julie Josse, Rozenn Lambert, Carine Antherieu, Sebastien Laurent, Veronique Loyer, Pascal Robin, Marie-Anne Guillouzo, Andre

    2010-11-15

    2-Amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) and 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) are two of the most common heterocyclic aromatic amines (HAA) produced during cooking of meat, fish and poultry. Both HAA produce different tumor profiles in rodents and are suspected to be carcinogenic in humans. In order to better understand the molecular basis of HAA toxicity, we have analyzed gene expression profiles in the metabolically competent human HepaRG cells using pangenomic oligonucleotide microarrays, after either a single (24-h) or a repeated (28-day) exposure to 10 {mu}M PhIP or MeIQx. The most responsive genes to both HAA were downstream targets of the arylhydrocarbon receptor (AhR): CYP1A1 and CYP1A2 after both time points and CYP1B1 and ALDH3A1 after 28 days. Accordingly, CYP1A1/1A2 induction in HAA-treated HepaRG cells was prevented by chemical inhibition or small interference RNA-mediated down-regulation of the AhR. Consistently, HAA induced activity of the CYP1A1 promoter, which contains a consensus AhR-related xenobiotic-responsive element (XRE). In addition, several other genes exhibited both time-dependent and compound-specific expression changes with, however, a smaller magnitude than previously reported for the prototypical AhR target genes. These changes concerned genes mainly related to cell growth and proliferation, apoptosis, and cancer. In conclusion, these results identify the AhR gene battery as the preferential target of PhIP and MeIQx in HepaRG cells and further support the hypothesis that intake of HAA in diet might increase human cancer risk.

  20. AHR Over-Expression in Papillary Thyroid Carcinoma: Clinical and Molecular Assessments in a Series of Italian Acromegalic Patients with a Long-Term Follow-Up

    PubMed Central

    Mian, Caterina; Ceccato, Filippo; Barollo, Susi; Watutantrige-Fernando, Sara; Albiger, Nora; Regazzo, Daniela; de Lazzari, Paola; Pennelli, Gianmaria; Rotondi, Sandra; Nacamulli, Davide; Pelizzo, Maria Rosa; Jaffrain-Rea, Marie-Lise; Grimaldi, Franco; Occhi, Gianluca; Scaroni, Carla

    2014-01-01

    Aim Acromegaly reportedly carries an increased risk of malignant and benign thyroid tumors, with a prevalence of thyroid cancer of around 3–7%. Germline mutations in the aryl-hydrocarbon receptor (AHR) interacting protein (AIP) have been identified in familial forms of acromegaly. The molecular and endocrine relationships between follicular thyroid growth and GH-secreting pituitary adenoma have yet to be fully established. Our aim was to study the prevalence of differentiated thyroid cancer (DTC) in acromegaly, focusing on the role of genetic events responsible for the onset of thyroid cancer. Methods Germline mutations in the AIP gene were assessed in all patients; BRAF and H-N-K RAS status was analyzed by direct sequencing in thyroid specimens, while immunohistochemistry was used to analyze the protein expression of AIP and AHR. A set of PTCs unrelated to acromegaly was also studied. Results 12 DTCs (10 papillary and 2 follicular carcinomas) were identified in a cohort of 113 acromegalic patients. No differences in GH/IGF-1 levels or disease activity emerged between patients with and without DTC, but the former were older and more often female. BRAF V600E was found in 70% of the papillary thyroid cancers; there were no RAS mutations. AIP protein expression was similar in neoplastic and normal cells, while AHR protein was expressed more in PTCs carrying BRAF mutations than in normal tissue, irrespective of acromegaly status. Conclusions The prevalence of DTC in acromegaly is around 11% and endocrinologists should bear this in mind, especially when examining elderly female patients with uninodular goiter. The DTC risk does not seem to correlate with GH/IGF-1 levels, while it may be associated with BRAF mutations and AHR over-expression. Genetic or epigenetic events probably play a part in promoting thyroid carcinoma. PMID:25019383

  1. TCDD and a putative endogenous AhR ligand, ITE, elicit the same immediate changes in gene expression in mouse lung fibroblasts.

    PubMed

    Henry, Ellen C; Welle, Stephen L; Gasiewicz, Thomas A

    2010-03-01

    The aryl hydrocarbon receptor (AhR), a ligand-dependent transcription factor, mediates toxicity of several classes of xenobiotics and also has important physiological roles in differentiation, reproduction, and immunity, although the endogenous ligand(s) mediating these functions is/are as yet unidentified. One candidate endogenous ligand, 2-(1'H-indolo-3'-carbonyl)-thiazole-4-carboxylic acid methyl ester (ITE), is a potent AhR agonist in vitro, activates the murine AhR in vivo, but does not induce toxicity. We hypothesized that ITE and the toxic ligand, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), may modify transcription of different sets of genes to account for their different toxicity. To test this hypothesis, primary mouse lung fibroblasts were exposed to 0.5muM ITE, 0.2nM TCDD, or vehicle for 4 h, and total gene expression was evaluated using microarrays. After this short-term and low-dose treatment, several hundred genes were changed significantly, and the response to ITE and TCDD was remarkably similar, both qualitatively and quantitatively. Induced gene sets included the expected battery of AhR-dependent xenobiotic-metabolizing enzymes, as well as several sets that reflect the inflammatory role of lung fibroblasts. Real time quantitative RT-qPCR assay of several selected genes confirmed these microarray data and further suggested that there may be kinetic differences in expression between ligands. These data suggest that ITE and TCDD elicit an analogous change in AhR conformation such that the initial transcription response is the same. Furthermore, if the difference in toxicity between TCDD and ITE is mediated by differences in gene expression, then it is likely that secondary changes enabled by the persistent TCDD, but not by the shorter lived ITE, are responsible.

  2. ALTERATIONS IN CALCIUM ION ACTIVITY BY ELF AND RF ELECTROMAGNETIC FIELDS

    EPA Science Inventory



    Alterations in calcium ion activity by ELF and RF electromagnetic fields

    Introduction

    Calcium ions play many important roles in biological systems. For example, calcium ion activity can be used as an indicator of second-messenger signal-transduction processe...

  3. In silico predictive studies of mAHR congener binding using homology modelling and molecular docking.

    PubMed

    Panda, Roshni; Cleave, A Suneetha Susan; Suresh, P K

    2014-09-01

    The aryl hydrocarbon receptor (AHR) is one of the principal xenobiotic, nuclear receptor that is responsible for the early events involved in the transcription of a complex set of genes comprising the CYP450 gene family. In the present computational study, homology modelling and molecular docking were carried out with the objective of predicting the relationship between the binding efficiency and the lipophilicity of different polychlorinated biphenyl (PCB) congeners and the AHR in silico. Homology model of the murine AHR was constructed by several automated servers and assessed by PROCHECK, ERRAT, VERIFY3D and WHAT IF. The resulting model of the AHR by MODWEB was used to carry out molecular docking of 36 PCB congeners using PatchDock server. The lipophilicity of the congeners was predicted using the XLOGP3 tool. The results suggest that the lipophilicity influences binding energy scores and is positively correlated with the same. Score and Log P were correlated with r = +0.506 at p = 0.01 level. In addition, the number of chlorine (Cl) atoms and Log P were highly correlated with r = +0.900 at p = 0.01 level. The number of Cl atoms and scores also showed a moderate positive correlation of r = +0.481 at p = 0.01 level. To the best of our knowledge, this is the first study employing PatchDock in the docking of AHR to the environmentally deleterious congeners and attempting to correlate structural features of the AHR with its biochemical properties with regards to PCBs. The result of this study are consistent with those of other computational studies reported in the previous literature that suggests that a combination of docking, scoring and ranking organic pollutants could be a possible predictive tool for investigating ligand-mediated toxicity, for their subsequent validation using wet lab-based studies.

  4. Low-dose dioxins alter gene expression related to cholesterol biosynthesis, lipogenesis, and glucose metabolism through the aryl hydrocarbon receptor-mediated pathway in mouse liver

    SciTech Connect

    Sato, Shoko; Shirakawa, Hitoshi Tomita, Shuhei; Ohsaki, Yusuke; Haketa, Keiichi; Tooi, Osamu; Santo, Noriaki; Tohkin, Masahiro; Furukawa, Yuji; Gonzalez, Frank J.; Komai, Michio

    2008-05-15

    2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is a common environmental contaminant. TCDD binds and activates the transcription factor aryl hydrocarbon receptor (AHR), leading to adverse biological responses via the alteration of the expression of various AHR target genes. Although small amounts of TCDD are consumed via contaminated daily foodstuffs and environmental exposures, the effects of low-dose TCDD on gene expression in animal tissues have not been clarified, while a number of genes affected by high-dose TCDD were reported. In this study, we comprehensively analyzed gene expression profiles in livers of C57BL/6N mice that were orally administered relatively low doses of TCDD (5, 50, or 500 ng/kg body weight (bw) day{sup -1}) for 18 days. The hepatic TCDD concentrations, measured by gas chromatography-mass spectrometry, were 1.2, 17, and 1063 pg toxicity equivalent quantity (TEQ)/g, respectively. The mRNA level of the cytochrome P450 CYP1A1 was significantly increased by treatment with only TCDD 500 ng/kg bw day{sup -1}. DNA microarray and quantitative RT-PCR analyses revealed changes in the expression of genes involved in the circadian rhythm, cholesterol biosynthesis, fatty acid synthesis, and glucose metabolism in the liver with at all doses of TCDD employed. However, repression of expression of genes involved in energy metabolism was not observed in the livers of Ahr-null mice that were administered the same dose of TCDD. These results indicate that changes in gene expression by TCDD are mediated by AHR and that exposure to low-dose TCDD could affect energy metabolism via alterations of gene expression.

  5. Enhancement of hypoxia-induced gene expression in fish liver by the aryl hydrocarbon receptor (AhR) ligand, benzo[a]pyrene (BaP).

    PubMed

    Yu, Richard Man Kit; Ng, Patrick Kwok Shing; Tan, Tianfeng; Chu, Daniel Ling Ho; Wu, Rudolf Shiu Sun; Kong, Richard Yuen Chong

    2008-11-21

    Fish in polluted coastal habitats commonly suffer simultaneous exposure to both hypoxia and xenobiotics. Although the adaptive molecular responses to each stress have been described, little is known about the interaction between the signaling pathways mediating these responses. Previous studies in mammalian hepatoma cell lines have shown that hypoxia-inducible factor (HIF)- and/or aryl hydrocarbon receptor (AhR)-activated gene expression is suppressed following co-exposure to hypoxia and the hallmark AhR ligand 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). However, whether similar crosstalk exists in the non-tumor liver tissues of fish and whether other non-TCDD ligands also play the same inhibitory role in this crosstalk remain unknown. Here, the in vivo hepatic mRNA expression profiles of multiple hypoxia- and AhR-responsive genes (later gene expression=mRNA expression of the gene) were examined in the orange-spotted grouper (Epinephelus coioides) upon single and combined exposures to hypoxia and benzo[a]pyrene (BaP). Combined exposure enhanced hypoxia-induced gene expression but did not significantly alter BaP-induced gene expression. Protein carbonyl content was markedly elevated in fish subjected to combined exposure, indicating accumulation of reactive oxygen species (ROS). Application of diethyldithiocarbamate (DDC) to hypoxia-treated grouper liver explants similarly exaggerated hypoxia-induced gene expression as in the combined stress tissues in vivo. These observations suggest that ROS derived from the combined hypoxia and BaP stress have a role in enhancing hypoxia-induced gene expression.

  6. A Model for Aryl Hydrocarbon Receptor-Activated Gene Expression Shows Potency and Efficacy Changes and Predicts Squelching Due to Competition for Transcription Co-Activators

    PubMed Central

    Simon, Ted W.; Budinsky, Robert A.; Rowlands, J. Craig

    2015-01-01

    A stochastic model of nuclear receptor-mediated transcription was developed based on activation of the aryl hydrocarbon receptor (AHR) by 2,3,7,8-tetrachlorodibenzodioxin (TCDD) and subsequent binding the activated AHR to xenobiotic response elements (XREs) on DNA. The model was based on effects observed in cells lines commonly used as in vitro experimental systems. Following ligand binding, the AHR moves into the cell nucleus and forms a heterodimer with the aryl hydrocarbon nuclear translocator (ARNT). In the model, a requirement for binding to DNA is that a generic coregulatory protein is subsequently bound to the AHR-ARNT dimer. Varying the amount of coregulator available within the nucleus altered both the potency and efficacy of TCDD for inducing for transcription of CYP1A1 mRNA, a commonly used marker for activation of the AHR. Lowering the amount of available cofactor slightly increased the EC50 for the transcriptional response without changing the efficacy or maximal response. Further reduction in the amount of cofactor reduced the efficacy and produced non-monotonic dose-response curves (NMDRCs) at higher ligand concentrations. The shapes of these NMDRCs were reminiscent of the phenomenon of squelching. Resource limitations for transcriptional machinery are becoming apparent in eukaryotic cells. Within single cells, nuclear receptor-mediated gene expression appears to be a stochastic process; however, intercellular communication and other aspects of tissue coordination may represent a compensatory process to maintain an organism’s ability to respond on a phenotypic level to various stimuli within an inconstant environment. PMID:26039703

  7. Influenza matrix protein 2 alters CFTR expression and function through its ion channel activity.

    PubMed

    Londino, James D; Lazrak, Ahmed; Jurkuvenaite, Asta; Collawn, James F; Noah, James W; Matalon, Sadis

    2013-05-01

    The human cystic fibrosis transmembrane conductance regulator (CFTR) is a cyclic AMP-activated chloride (Cl(-)) channel in the lung epithelium that helps regulate the thickness and composition of the lung epithelial lining fluid. We investigated whether influenza M2 protein, a pH-activated proton (H(+)) channel that traffics to the plasma membrane of infected cells, altered CFTR expression and function. M2 decreased CFTR activity in 1) Xenopus oocytes injected with human CFTR, 2) epithelial cells (HEK-293) stably transfected with CFTR, and 3) human bronchial epithelial cells (16HBE14o-) expressing native CFTR. This inhibition was partially reversed by an inhibitor of the ubiquitin-activating enzyme E1. Next we investigated whether the M2 inhibition of CFTR activity was due to an increase of secretory organelle pH by M2. Incubation of Xenopus oocytes expressing CFTR with ammonium chloride or concanamycin A, two agents that alkalinize the secretory pathway, inhibited CFTR activity in a dose-dependent manner. Treatment of M2- and CFTR-expressing oocytes with the M2 ion channel inhibitor amantadine prevented the loss in CFTR expression and activity; in addition, M2 mutants, lacking the ability to transport H(+), did not alter CFTR activity in Xenopus oocytes and HEK cells. Expression of an M2 mutant retained in the endoplasmic reticulum also failed to alter CFTR activity. In summary, our data show that M2 decreases CFTR activity by increasing secretory organelle pH, which targets CFTR for destruction by the ubiquitin system. Alteration of CFTR activity has important consequences for fluid regulation and may potentially modify the immune response to viral infection.

  8. Influenza matrix protein 2 alters CFTR expression and function through its ion channel activity

    PubMed Central

    Londino, James D.; Lazrak, Ahmed; Jurkuvenaite, Asta; Collawn, James F.; Noah, James W.

    2013-01-01

    The human cystic fibrosis transmembrane conductance regulator (CFTR) is a cyclic AMP-activated chloride (Cl−) channel in the lung epithelium that helps regulate the thickness and composition of the lung epithelial lining fluid. We investigated whether influenza M2 protein, a pH-activated proton (H+) channel that traffics to the plasma membrane of infected cells, altered CFTR expression and function. M2 decreased CFTR activity in 1) Xenopus oocytes injected with human CFTR, 2) epithelial cells (HEK-293) stably transfected with CFTR, and 3) human bronchial epithelial cells (16HBE14o−) expressing native CFTR. This inhibition was partially reversed by an inhibitor of the ubiquitin-activating enzyme E1. Next we investigated whether the M2 inhibition of CFTR activity was due to an increase of secretory organelle pH by M2. Incubation of Xenopus oocytes expressing CFTR with ammonium chloride or concanamycin A, two agents that alkalinize the secretory pathway, inhibited CFTR activity in a dose-dependent manner. Treatment of M2- and CFTR-expressing oocytes with the M2 ion channel inhibitor amantadine prevented the loss in CFTR expression and activity; in addition, M2 mutants, lacking the ability to transport H+, did not alter CFTR activity in Xenopus oocytes and HEK cells. Expression of an M2 mutant retained in the endoplasmic reticulum also failed to alter CFTR activity. In summary, our data show that M2 decreases CFTR activity by increasing secretory organelle pH, which targets CFTR for destruction by the ubiquitin system. Alteration of CFTR activity has important consequences for fluid regulation and may potentially modify the immune response to viral infection. PMID:23457187

  9. Altered Neural Activity Associated with Mindfulness during Nociception: A Systematic Review of Functional MRI

    PubMed Central

    Bilevicius, Elena; Kolesar, Tiffany A.; Kornelsen, Jennifer

    2016-01-01

    Objective: To assess the neural activity associated with mindfulness-based alterations of pain perception. Methods: The Cochrane Central, EMBASE, Ovid Medline, PsycINFO, Scopus, and Web of Science databases were searched on 2 February 2016. Titles, abstracts, and full-text articles were independently screened by two reviewers. Data were independently extracted from records that included topics of functional neuroimaging, pain, and mindfulness interventions. Results: The literature search produced 946 total records, of which five met the inclusion criteria. Records reported pain in terms of anticipation (n = 2), unpleasantness (n = 5), and intensity (n = 5), and how mindfulness conditions altered the neural activity during noxious stimulation accordingly. Conclusions: Although the studies were inconsistent in relating pain components to neural activity, in general, mindfulness was able to reduce pain anticipation and unpleasantness ratings, as well as alter the corresponding neural activity. The major neural underpinnings of mindfulness-based pain reduction consisted of altered activity in the anterior cingulate cortex, insula, and dorsolateral prefrontal cortex. PMID:27104572

  10. Medullary raphe neuron activity is altered during fictive cough in the decerebrate cat.

    PubMed

    Baekey, David M; Morris, Kendall F; Nuding, Sarah C; Segers, Lauren S; Lindsey, Bruce G; Shannon, Roger

    2003-01-01

    Chemical lesions in the medullary raphe nuclei region influence cough. This study examined whether firing patterns of caudal medullary midline neurons were altered during cough. Extracellular neuron activity was recorded with microelectrode arrays in decerebrated, neuromuscular-blocked, ventilated cats. Cough-like motor patterns (fictive cough) in phrenic and lumbar nerves were elicited by mechanical stimulation of the intrathoracic trachea. Discharge patterns of respiratory and nonrespiratory-modulated neurons were altered during cough cycles (58/133); 45 increased and 13 decreased activity. Fourteen cells changed firing rate during the inspiratory and/or expiratory phases of cough. Altered patterns in 43 cells were associated with the duration of, or extended beyond, the cough episodes. The different response categories suggest that multiple factors influence the discharge patterns during coughing: e.g., respiratory-modulated and tonic inputs and intrinsic connections. These results suggest involvement of midline neurons (i.e., raphe nuclei) in the cough reflex.

  11. Progesterone, as well as 17β-estradiol, is important for regulating AHR battery homoeostasis in the rat uterus.

    PubMed

    Rataj, Felicitas; Möller, Frank Josef; Jähne, Maria; Hönscheid, Pia; Zierau, Oliver; Vollmer, Günter; Kretzschmar, Georg

    2015-03-01

    Several studies indicate that the aryl hydrocarbon receptor (AHR), which plays an important role in mediating the toxicity of many industrial chemicals, plays an important role in the physiology of female reproductive tract organs. This makes it likely that the AHR and additional components of the AHR signalling pathway are under the control of female sex steroids. In a previous study, we could already demonstrate the regulation of many members of the AHR battery by 17β-estradiol (E2) in the uterus of rats. In this study, we addressed the potential role of progesterone (P4) in this context. In a comparative approach using ovariectomized rats which were treated for 3 days with either vehicle control, E2, progesterone (P4) or the combination of both hormones in addition to sham-operated animals, we could demonstrate that in addition to E2, P4 is also an important factor in regulating AHR signalling in the rat uterus. P4 has effects similar to E2 on uterine Ahr, Arnt and Arnt2 mRNA levels, resulting in a downregulation of these genes, while the E2-mediated downregulation of key AHR response genes Cyp1a1, Gsta2 and Ugt1 is completely antagonized by P4. As with E2, P4 leads to an increase in uterine AHR levels, especially in the endometrial epithelium despite the decrease in corresponding mRNA levels. This indicates a complex gene-specific regulatory network involving E2, P4 and possibly AHR itself to maintain all components of the AHR signalling cascade at the required levels during all stages of the oestrous cycle and pregnancy.

  12. 76 FR 80447 - Eighth Meeting: RTCA Special Committee 219: Attitude and Heading Reference Systems (AHRS)

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-23

    ... Federal Aviation Administration Eighth Meeting: RTCA Special Committee 219: Attitude and Heading Reference...). ACTION: Notice of RTCA Special Committee 219: Attitude and Heading Reference Systems (AHRS). SUMMARY: The FAA is issuing this notice to advise the public of the eighth meeting of RTCA Special Committee...

  13. EXPRESSION OF AHR AND ARNT MRNA IN CULTURED HUMAN ENDOMETRIAL EXPLANTS EXPOSED TO TCDD

    EPA Science Inventory

    Expression of AhR and ARNT mRNA in cultured human endometrial explants exposed to TCDD.

    Pitt JA, Feng L, Abbott BD, Schmid J, Batt RE, Costich TG, Koury ST, Bofinger DP.

    Curriculum in Toxicology, University of North Carolina, Chapel Hill, NC 27599, USA.

    Endom...

  14. Outcome of Children with Hyperventilation-Induced High-Amplitude Rhythmic Slow Activity with Altered Awareness

    ERIC Educational Resources Information Center

    Barker, Alexander; Ng, Joanne; Rittey, Christopher D. C.; Kandler, Rosalind H.; Mordekar, Santosh R.

    2012-01-01

    Hyperventilation-induced high-amplitude rhythmic slow activity with altered awareness (HIHARS) is increasingly being identified in children and is thought to be an age-related non-epileptic electrographic phenomenon. We retrospectively investigated the clinical outcome in 15 children (six males, nine females) with HIHARS (mean age 7y, SD 1y 11mo;…

  15. ALTERATION OF CARDIAC ELECTRICAL ACTIVITY BY WATER-LEACHABLE COMPONENTS OF RESIDUAL OIL FLY ASH (ROFA)

    EPA Science Inventory

    Alteration of cardiac electrical activity by water-leachable components
    of residual oil fly ash (ROFA)

    Desuo Wang, Yuh-Chin T. Huang*, An Xie, Ting Wang

    *Human Studies Division, NHEERL, US EPA
    104 Mason Farm Road, Chapel Hill, NC 27599
    Department of Basic ...

  16. Altered lower leg muscle activation patterns in patients with cerebral palsy during cycling on an ergometer

    PubMed Central

    Alves-Pinto, Ana; Blumenstein, Tobias; Turova, Varvara; Lampe, Renée

    2016-01-01

    Objective Cycling on a recumbent ergometer constitutes one of the most popular rehabilitation exercises in cerebral palsy (CP). However, no control is performed on how muscles are being used during training. Given that patients with CP present altered muscular activity patterns during cycling or walking, it is possible that an incorrect pattern of muscle activation is being promoted during rehabilitation cycling. This study investigated patterns of muscular activation during cycling on a recumbent ergometer in patients with CP and whether those patterns are determined by the degree of spasticity and of mobility. Methods Electromyographic (EMG) recordings of lower leg muscle activation during cycling on a recumbent ergometer were performed in 14 adult patients diagnosed with CP and five adult healthy participants. EMG recordings were done with an eight-channel EMG system built in the laboratory. The activity of the following muscles was recorded: Musculus rectus femoris, Musculus biceps femoris, Musculus tibialis anterior, and Musculus gastrocnemius. The degree of muscle spasticity and mobility was assessed using the Modified Ashworth Scale and the Gross Motor Function Classification System, respectively. Muscle activation patterns were described in terms of onset and duration of activation as well as duration of cocontractions. Results Muscle activation in CP was characterized by earlier onsets, longer periods of activation, a higher occurrence of agonist–antagonist cocontractions, and a more variable cycling tempo in comparison to healthy participants. The degree of altered muscle activation pattern correlated significantly with the degree of spasticity. Conclusion This study confirmed the occurrence of altered lower leg muscle activation patterns in patients with CP during cycling on a recumbent ergometer. There is a need to develop feedback systems that can inform patients and therapists of an incorrect muscle activation during cycling and support the training

  17. Induction of human UGT1A1 by bilirubin through AhR dependent pathway.

    PubMed

    Togawa, Hiroshi; Shinkai, Shigeko; Mizutani, Takaharu

    2008-12-01

    UDP-glucuronosyltransferase1A1 (UGT1A1) plays a key role to conjugate bilirubin and preventing jaundice, but there is no report showing the induction of human UGT1A1 (UGT1A1) by bilirubin. In this report, we show findings of the induction of the reporter gene (-3475/+14) of UGT1A1 in HepG2 cells by bilirubin at 50 microM, 100 microM, with human aryl hydrocarbon receptor (hAhR). We confirmed that induction of the reporter gene by bilirubin is dependent on the position of the xenobiotic responsive element (XRE) (-3328/-3319) of UGT1A1, because the XRE deletion UGT1A1 gene did not respond to stimulation by a complex of bilirubin and hAhR. alpha-Naphthoflavone (alpha-NF) of a typical AhR antagonist at 50 microM inhibited induction by bilirubin, suggesting that bilirubin stimulates through binding with hAhR. Meanwhile, bilirubin itself did not stimulate the induction of AhR, because we detected no-elevation of the mRNA level of AhR by RT-PCR. These results indicate that the induction of UGT1A1 by bilirubin-AhR did not depend on the elevation of AhR but on ligand binding. From this result, we considered that high bilirubin in neonates must induce the elevation of UGT1A1 after birth to prevent jaundice, and bilirubin in adults also regulates the level of UGT1A1. This is the first report showing direct induction of UGT1A1 by a bilirubin through AhR pathway. PMID:19356098

  18. Platelet Activation in Human Immunodeficiency Virus Type-1 Patients Is Not Altered with Cocaine Abuse

    PubMed Central

    Kiebala, Michelle; Singh, Meera V.; Piepenbrink, Michael S.; Qiu, Xing; Kobie, James J.; Maggirwar, Sanjay B.

    2015-01-01

    Recent work has indicated that platelets, which are anucleate blood cells, significantly contribute to inflammatory disorders. Importantly, platelets also likely contribute to various inflammatory secondary disorders that are increasingly associated with Human Immunodeficiency Virus Type-1 (HIV) infection including neurological impairments and cardiovascular complications. Indeed, HIV infection is often associated with increased levels of platelet activators. Additionally, cocaine, a drug commonly abused by HIV-infected individuals, leads to increased platelet activation in humans. Considering that orchestrated signaling mechanisms are essential for platelet activation, and that nuclear factor-kappa B (NF-κB) inhibitors can alter platelet function, the role of NF-κB signaling in platelet activation during HIV infection warrants further investigation. Here we tested the hypothesis that inhibitory kappa B kinase complex (IKK) activation would be central for platelet activation induced by HIV and cocaine. Whole blood from HIV-positive and HIV-negative individuals, with or without cocaine abuse was used to assess platelet activation via flow cytometry whereas IKK activation was analyzed by performing immunoblotting and in vitro kinase assays. We demonstrate that increased platelet activation in HIV patients, as measured by CD62P expression, is not altered with reported cocaine use. Furthermore, cocaine and HIV do not activate platelets in whole blood when treated ex vivo. Finally, HIV-induced platelet activation does not involve the NF-κB signaling intermediate, IKKβ. Platelet activation in HIV patients is not altered with cocaine abuse. These results support the notion that non-IKK targeting approaches will be better suited for the treatment of HIV-associated inflammatory disorders. PMID:26076359

  19. MULTIPLE EPISODES OF IGNEOUS ACTIVITY, MINERALIZATION, AND ALTERATION IN THE WESTERN TUSHAR MOUNTAINS, UTAH.

    USGS Publications Warehouse

    Cunningham, Charles G.; Steven, Thomas A.; Campbell, David L.; Naeser, Charles W.; Pitkin, James A.; Duval, Joseph S.

    1984-01-01

    The report outlines the complex history of igneous activity and associated alteration and mineralization in the western Tushar Mountains, Utah and pointss out implciations for minerals exploration. The area has been subjected to recurrent episodes of igneous intrusion, hydrothermal alteration, and mineralization, and the mineral-resource potential of the different mineralized areas is directly related to local geologic history. The mineral commodities to be expected vary from one hydrothermal system to another, and from one depth to another within any given system. Uranium and molybdenum seem likely to have the greatest economic potential, although significant concentrations of gold may also exist.

  20. The alteration of components in the fermented Hwangryunhaedok-tang and its neuroprotective activity

    PubMed Central

    Yang, Hye Jin; Weon, Jin Bae; Lee, Bohyoung; Ma, Choong Je

    2011-01-01

    Background: Hwangryunhaedok-tang is a traditional herbal prescription that has sedative activity, hypotensive and anti-bacterial effects. Objective: In this study, we investigated the alteration of contents of components in Hwangryunhaedok-tang, antioxidant activity and neuroprotective activity by fermentation with Lactobacillus acidophilus KFRI 128. Materials and Methods: Contents of three marker compounds (geniposide, berberine and palmatine) and unknown compounds in the Hwangryunhaedok-tang (HR) and the fermented Hwangryunhaedok-tang (FHR) were measured and compared using the established high-performance liqued chromatograph coupled with a photodiode (HPLC-DAD) method. The antioxidant activity of HR and FHR were determined by DPPH free radical and hydrogen peroxide (H2O2) scavenging assay. Also, the neuroprotective activities of HR and FHR against glutamate-induced oxidative stress in a mouse hippocampal cell line (HT22) were evaluated by MTT assay. Results: The contents of geniposide and palmatine were decreased but the content of berberine was increased in the FHR. And the contents of unknown compounds (1), (2), (3), (4) and (5) in the HR were altered by fermentation. Electron donating activity (EDA, %) value of FHR was higher than HR for DPPH radical scavenging activity and H2O2 scavenging activity, respectively. In the MTT assay, FHR showed more potent neuroprotective activity than HR by 513.90%. Conclusion: The FHR using microorganism could convert compounds in HR and enhance the antioxidant and neuroprotective activity. PMID:21969791

  1. Skeletal muscle plasticity: cellular and molecular responses to altered physical activity paradigms

    NASA Technical Reports Server (NTRS)

    Baldwin, Kenneth M.; Haddad, Fadia

    2002-01-01

    The goal of this article is to examine our current understanding of the chain of events known to be involved in the adaptive process whereby specific genes and their protein products undergo altered expression; specifically, skeletal muscle adaptation in response to altered loading states will be discussed, with a special focus on the regulation of the contractile protein, myosin heavy chain gene expression. This protein, which is both an important structural and regulatory protein comprising the contractile apparatus, can be expressed as different isoforms, thereby having an impact on the functional diversity of the muscle. Because the regulation of the myosin gene family is under the control of a complex set of processes including, but not limited to, activity, hormonal, and metabolic factors, this protein will serve as a cellular "marker" for studies of muscle plasticity in response to various mechanical perturbations in which the quantity and type of myosin isoform, along with other important cellular proteins, are altered in expression.

  2. Non-enzymatic Glycation of Almond Cystatin Leads to Conformational Changes and Altered Activity.

    PubMed

    Siddiqui, Azad A; Sohail, Aamir; Bhat, Sheraz A; Rehman, Md T; Bano, Bilqees

    2015-01-01

    The non-enzymatic reaction between proteins and reducing sugars, known as glycation, leads to the formation of inter and intramolecular cross-links of proteins. Stable end products called as advanced Maillard products or advanced glycation end products (AGEs) have received tremendous attention since last decades. It was suggested that the formation of AGEs not only modify the conformation of proteins but also induces altered biological activity. In this study, cystatin purified from almond was incubated with three different sugars namely D-ribose, fructose and lactose to monitor the glycation process. Structural changes induced in cystatin on glycation were studied using UV-visible spectroscopy, fluorescence spectroscopy, CD and FTIR techniques. Glycated cystatin was found to migrate slower on electrophoresis as compared to control cystatin. Biological activity data of glycated cystatin showed that D-ribose was most effective in inducing conformational changes with maximum altered activity.

  3. Cortisol's effects on hippocampal activation in depressed patients are related to alterations in memory formation.

    PubMed

    Abercrombie, Heather C; Jahn, Allison L; Davidson, Richard J; Kern, Simone; Kirschbaum, Clemens; Halverson, Jerry

    2011-01-01

    Many investigators have hypothesized that brain response to cortisol is altered in depression. However, neural activation in response to exogenously manipulated cortisol elevations has not yet been directly examined in depressed humans. Animal research shows that glucocorticoids have robust effects on hippocampal function, and can either enhance or suppress neuroplastic events in the hippocampus depending on a number of factors. We hypothesized that depressed individuals would show 1) altered hippocampal response to exogenous administration of cortisol, and 2) altered effects of cortisol on learning. In a repeated-measures design, 19 unmedicated depressed and 41 healthy individuals completed two fMRI scans. Fifteen mg oral hydrocortisone (i.e., cortisol) or placebo (order randomized and double-blind) was administered 1 h prior to encoding of emotional and neutral words during fMRI scans. Data analysis examined the effects of cortisol administration on 1) brain activation during encoding, and 2) subsequent free recall for words. Cortisol affected subsequent recall performance in depressed but not healthy individuals. We found alterations in hippocampal response to cortisol in depressed women, but not in depressed men (who showed altered response to cortisol in other regions, including subgenual prefrontal cortex). In both depressed men and women, cortisol's effects on hippocampal function were positively correlated with its effects on recall performance assessed days later. Our data provide evidence that in depressed compared to healthy women, cortisol's effects on hippocampal function are altered. Our data also show that in both depressed men and women, cortisol's effects on emotional memory formation and hippocampal function are related.

  4. Evidence for microbial activity at the glass-alteration interface in oceanic basalts

    NASA Astrophysics Data System (ADS)

    Torsvik, Terje; Furnes, Harald; Muehlenbachs, Karlis; Thorseth, Ingunn H.; Tumyr, Ole

    1998-10-01

    A detailed microbiological and geochemical study related to the alteration of basaltic glass of pillow lavas from the oceanic crust recovered from Hole 896A on the Costa Rica Rift (penetrating 290 m into the volcanic basement) has been carried out. A number of independent observations, pointing to the influence of microbes, may be summarized as follows: (1) Alteration textures are reminiscent of microbes in terms of form and shape. (2) Altered material contains appreciable amounts of C, N and K, and the N/C ratios are comparable to those of nitrogen-starved bacteria. (3) Samples stained with a dye (DAPI) that binds specifically to nucleic acids show the presence of DNA in the altered glass. Further, staining with fluorescent labeled oligonucleotide probes that hybridize specifically to 16S-ribosomal RNA of bacteria and archaea demonstrate their presence in the altered part of the glass. (4) Disseminated carbonate in the glassy margin of the majority of pillows shows δ 13C values, significantly lower than that of fresh basalt, also suggests biological activity. The majority of the samples have δ 18O values indicating temperatures of 20-100°C, which is in the range of mesophilic and thermophilic micro-organisms.

  5. The aryl hydrocarbon receptor suppresses osteoblast proliferation and differentiation through the activation of the ERK signaling pathway

    SciTech Connect

    Yu, Haitao; Du, Yuxuan; Zhang, Xulong; Sun, Ying; Li, Shentao; Dou, Yunpeng; Li, Zhanguo; Yuan, Huihui; Zhao, Wenming

    2014-11-01

    Ahr activation is known to be associated with synovitis and exacerbated rheumatoid arthritis (RA), but its contributions to bone loss have not been completely elucidated. Osteoblast proliferation and differentiation are abnormal at the erosion site in RA. Here, we reported that the expression of Ahr was increased in the hind paws' bone upon collagen-induced arthritis (CIA) in mice, and the levels of Ahr were negatively correlated with bone mineral density (BMD). In addition, immunofluorescent staining showed that the high expression of Ahr was mainly localized in osteoblasts from the CIA mice compared to normal controls. Moreover, the luciferase intensity of Ahr in the nucleus increased by 12.5% in CIA osteoblasts compared to that in normal controls. In addition, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) activation of the Ahr inhibited pre-osteoblast MC3T3-E1 cellular proliferation and differentiation in a dose-dependent manner. Interestingly, the levels of alkaline phosphatase (ALP) mRNA expression in the osteoblasts of CIA mice were reduced compared to normal controls. In contrast, decreased ALP expression by activated Ahr was completely reversed after pretreatment with an Ahr inhibitor (CH-223191) in MC3T3-E1 cell lines and primary osteoblasts on day 5. Our data further showed that activation of Ahr promoted the phosphorylation of ERK after 5 days. Moreover, Ahr-dependent activation of the ERK signaling pathway decreased the levels of proliferation cells and inhibited ALP activity in MC3T3-E1 cells. These results demonstrated that the high expression of Ahr may suppress osteoblast proliferation and differentiation through activation of the ERK signaling pathway, further enabling bone erosion in CIA mice. - Highlights: • The upregulation of Ahr was localized in osteoblasts of CIA mice. • The overexpression of Ahr suppressed osteoblast development. • The Ahr activated ERK signaling pathway to exacerbate bone erosion.

  6. Evidence for altered amygdala activation in schizophrenia in an adaptive emotion recognition task.

    PubMed

    Mier, Daniela; Lis, Stefanie; Zygrodnik, Karina; Sauer, Carina; Ulferts, Jens; Gallhofer, Bernd; Kirsch, Peter

    2014-03-30

    Deficits in social cognition seem to present an intermediate phenotype for schizophrenia, and are known to be associated with an altered amygdala response to faces. However, current results are heterogeneous with respect to whether this altered amygdala response in schizophrenia is hypoactive or hyperactive in nature. The present study used functional magnetic resonance imaging to investigate emotion-specific amygdala activation in schizophrenia using a novel adaptive emotion recognition paradigm. Participants comprised 11 schizophrenia outpatients and 16 healthy controls who viewed face stimuli expressing emotions of anger, fear, happiness, and disgust, as well as neutral expressions. The adaptive emotion recognition approach allows the assessment of group differences in both emotion recognition performance and associated neuronal activity while also ensuring a comparable number of correctly recognized emotions between groups. Schizophrenia participants were slower and had a negative bias in emotion recognition. In addition, they showed reduced differential activation during recognition of emotional compared with neutral expressions. Correlation analyses revealed an association of a negative bias with amygdala activation for neutral facial expressions that was specific to the patient group. We replicated previous findings of affected emotion recognition in schizophrenia. Furthermore, we demonstrated that altered amygdala activation in the patient group was associated with the occurrence of a negative bias. These results provide further evidence for impaired social cognition in schizophrenia and point to a central role of the amygdala in negative misperceptions of facial stimuli in schizophrenia.

  7. Motivation alters response bias and neural activation patterns in a perceptual decision-making task.

    PubMed

    Reckless, G E; Bolstad, I; Nakstad, P H; Andreassen, O A; Jensen, J

    2013-05-15

    Motivation has been demonstrated to affect individuals' response strategies in economic decision-making, however, little is known about how motivation influences perceptual decision-making behavior or its related neural activity. Given the important role motivation plays in shaping our behavior, a better understanding of this relationship is needed. A block-design, continuous performance, perceptual decision-making task where participants were asked to detect a picture of an animal among distractors was used during functional magnetic resonance imaging (fMRI). The effect of positive and negative motivation on sustained activity within regions of the brain thought to underlie decision-making was examined by altering the monetary contingency associated with the task. In addition, signal detection theory was used to investigate the effect of motivation on detection sensitivity, response bias and response time. While both positive and negative motivation resulted in increased sustained activation in the ventral striatum, fusiform gyrus, left dorsolateral prefrontal cortex (DLPFC) and ventromedial prefrontal cortex, only negative motivation resulted in the adoption of a more liberal, closer to optimal response bias. This shift toward a liberal response bias correlated with increased activation in the left DLPFC, but did not result in improved task performance. The present findings suggest that motivation alters aspects of the way perceptual decisions are made. Further, this altered response behavior is reflected in a change in left DLPFC activation, a region involved in the computation of perceptual decisions.

  8. Activation of Matrix Metalloproteinase-3 is altered at the frog neuromuscular junction following changes in synaptic activity.

    PubMed

    VanSaun, M; Humburg, B C; Arnett, M G; Pence, M; Werle, M J

    2007-09-15

    The extracellular matrix surrounding the neuromuscular junction is a highly specialized and dynamic structure. Matrix Metalloproteinases are enzymes that sculpt the extracellular matrix. Since synaptic activity is critical to the structure and function of this synapse, we investigated whether changes in synaptic activity levels could alter the activity of Matrix Metalloproteinases at the neuromuscular junction. In particular, we focused on Matrix Metalloproteinase 3 (MMP3), since antibodies to MMP3 recognize molecules at the frog neuromuscular junction, and MMP3 cleaves a number of synaptic basal lamina molecules, including agrin. Here we show that the fluorogenic compound (M2300) can be used to perform in vivo proteolytic imaging of the frog neuromuscular junction to directly measure the activity state of MMP3. Application of this compound reveals that active MMP3 is concentrated at the normal frog neuromuscular junction, and is tightly associated with the terminal Schwann cell. Blocking presynaptic activity via denervation, or TTX nerve blockade, results in a decreased level of active MMP3 at the neuromuscular junction. The loss of active MMP3 at the neuromuscular junction in denervated muscles can result from decreased activation of pro-MMP3, or it could result from increased inhibition of MMP3. These results support the hypothesis that changes in synaptic activity can alter the level of active MMP3 at the neuromuscular junction. PMID:17525979

  9. The Search for Endogenous Activators of the Aryl Hydrocarbon Receptor

    PubMed Central

    Nguyen, Linh P.; Bradfield, Christopher A.

    2008-01-01

    In its simplest aspect, this review is an attempt to describe the major ligand classes of the aryl hydrocarbon receptor (AHR). A grander objective is to provide models that may help define the physiological activator or “endogenous ligand” of the AHR. We begin by presenting evidence that supports a developmental function for the AHR. This is followed by proposing mechanisms by which an endogenous ligand and consequent AHR activation might be important during normal physiology and development. With this background, we then present a survey of the known xenobiotic, endogenous, dietary and “un-conventional” activators of the AHR. When possible, this includes information about their induction potency, receptor binding affinity and potential for exposure. Because of the essential function of the AHR in embryonic development, we discuss the candidacy of each of these compounds as physiologically important activators. PMID:18076143

  10. OMP gene deletion results in an alteration in odorant-induced mucosal activity patterns.

    PubMed

    Youngentob, S L; Kent, P F; Margolis, F L

    2003-12-01

    Previous behavioral work, using a complex five-odorant identification task, demonstrated that olfactory marker protein (OMP) is critically involved in odor processing to the extent that its loss results in an alteration in odorant quality perception. Exactly how the lack of OMP exerts its influence on the perception of odorant quality is unknown. However, there is considerable neurophysiological evidence that different odorants produce different spatiotemporal patterns of neural activity at the level of the mucosa and that these patterns predict the psychophysically determined perceptual relationship among odorants. In this respect, OMP gene deletion is known to result in a constellation of physiologic defects (i.e., marked reduction in the electroolfactogram (EOG) and altered response and recovery kinetics) that would be expected to alter the odorant-induced spatiotemporal activity patterns that are characteristic of different odorants. This, in turn, would be expected to alter the spatiotemporal patterning of information that results from the mucosal projection onto the bulb, thereby changing odorant quality perception. To test the hypothesis that odorant-induced mucosal activity patterns are altered in mice lacking the gene for OMP, we optically recorded the fluorescent changes in response to odorant stimulation from both the septum and turbinates of both OMP-null and control mice using a voltage-sensitive dye (di-4-ANEPPS Molecular Probes, Eugene, OR) and a Dalsa 120 x 120, 12-bit CCD camera. To maintain continuity with the previous behavioral work, the odorants 2-propanol, citral, carvone, ethylacetoacetate, and propyl acetate were again used. Each odorant was randomly presented to each mucosal surface in a Latin-Square design. The results of this study demonstrated that, for both mouse strains, there do indeed exist different spatiotemporal activity patterns for different odorants. More importantly, however, these patterns significantly differed between OMP

  11. Altered metabolism of gut microbiota contributes to chronic immune activation in HIV-infected individuals.

    PubMed

    Vázquez-Castellanos, J F; Serrano-Villar, S; Latorre, A; Artacho, A; Ferrús, M L; Madrid, N; Vallejo, A; Sainz, T; Martínez-Botas, J; Ferrando-Martínez, S; Vera, M; Dronda, F; Leal, M; Del Romero, J; Moreno, S; Estrada, V; Gosalbes, M J; Moya, A

    2015-07-01

    Altered interplay between gut mucosa and microbiota during treated HIV infection may possibly contribute to increased bacterial translocation and chronic immune activation, both of which are predictors of morbidity and mortality. Although a dysbiotic gut microbiota has recently been reported in HIV+ individuals, the metagenome gene pool associated with HIV infection remains unknown. The aim of this study is to characterize the functional gene content of gut microbiota in HIV+ patients and to define the metabolic pathways of this bacterial community, which is potentially associated with immune dysfunction. We determined systemic markers of innate and adaptive immunity in a cohort of HIV-infected individuals on successful antiretroviral therapy without comorbidities and in healthy non-HIV-infected subjects. Metagenome sequencing revealed an altered functional profile, with enrichment of the genes involved in various pathogenic processes, lipopolysaccharide biosynthesis, bacterial translocation, and other inflammatory pathways. In contrast, we observed depletion of genes involved in amino acid metabolism and energy processes. Bayesian networks showed significant interactions between the bacterial community, their altered metabolic pathways, and systemic markers of immune dysfunction. This study reveals altered metabolic activity of microbiota and provides novel insight into the potential host-microbiota interactions driving the sustained inflammatory state in successfully treated HIV-infected patients. PMID:25407519

  12. Altered metabolism of gut microbiota contributes to chronic immune activation in HIV-infected individuals.

    PubMed

    Vázquez-Castellanos, J F; Serrano-Villar, S; Latorre, A; Artacho, A; Ferrús, M L; Madrid, N; Vallejo, A; Sainz, T; Martínez-Botas, J; Ferrando-Martínez, S; Vera, M; Dronda, F; Leal, M; Del Romero, J; Moreno, S; Estrada, V; Gosalbes, M J; Moya, A

    2015-07-01

    Altered interplay between gut mucosa and microbiota during treated HIV infection may possibly contribute to increased bacterial translocation and chronic immune activation, both of which are predictors of morbidity and mortality. Although a dysbiotic gut microbiota has recently been reported in HIV+ individuals, the metagenome gene pool associated with HIV infection remains unknown. The aim of this study is to characterize the functional gene content of gut microbiota in HIV+ patients and to define the metabolic pathways of this bacterial community, which is potentially associated with immune dysfunction. We determined systemic markers of innate and adaptive immunity in a cohort of HIV-infected individuals on successful antiretroviral therapy without comorbidities and in healthy non-HIV-infected subjects. Metagenome sequencing revealed an altered functional profile, with enrichment of the genes involved in various pathogenic processes, lipopolysaccharide biosynthesis, bacterial translocation, and other inflammatory pathways. In contrast, we observed depletion of genes involved in amino acid metabolism and energy processes. Bayesian networks showed significant interactions between the bacterial community, their altered metabolic pathways, and systemic markers of immune dysfunction. This study reveals altered metabolic activity of microbiota and provides novel insight into the potential host-microbiota interactions driving the sustained inflammatory state in successfully treated HIV-infected patients.

  13. The hyperactive syndrome: metanalysis of genetic alterations, pharmacological treatments and brain lesions which increase locomotor activity.

    PubMed

    Viggiano, Davide

    2008-12-01

    The large number of transgenic mice realized thus far with different purposes allows addressing new questions, such as which animals, over the entire set of transgenic animals, show a specific behavioural abnormality. In the present study, we have used a metanalytical approach to organize a database of genetic modifications, brain lesions and pharmacological interventions that increase locomotor activity in animal models. To further understand the resulting data set, we have organized a second database of the alterations (genetic, pharmacological or brain lesions) that reduce locomotor activity. Using this approach, we estimated that 1.56% of the genes in the genome yield to hyperactivity and 0.75% of genes produce hypoactivity when altered. These genes have been classified into genes for neurotransmitter systems, hormonal, metabolic systems, ion channels, structural proteins, transcription factors, second messengers and growth factors. Finally, two additional classes included animals with neurodegeneration and inner ear abnormalities. The analysis of the database revealed several unexpected findings. First, the genes that, when mutated, induce hyperactive behaviour do not pertain to a single neurotransmitter system. In fact, alterations in most neurotransmitter systems can give rise to a hyperactive phenotype. In contrast, fewer changes can decrease locomotor activity. Specifically, genetic and pharmacological alterations that enhance the dopamine, orexin, histamine, cannabinoids systems or that antagonize the cholinergic system induce an increase in locomotor activity. Similarly, imbalances in the two main neurotransmitters of the nervous system, GABA and glutamate usually result in hyperactive behaviour. It is remarkable that no genetic alterations pertaining to the GABA system have been reported to reduce locomotor behaviour. Other neurotransmitters, such as norepinephrine and serotonin, have a more complex influence. For instance, a decrease in norepinephrine

  14. [Alterations in recruitment and activation of Rab proteins during mycobacterial infection].

    PubMed

    Castaño, Diana; Rojas, Mauricio

    2010-01-01

    At the phagosome level, Mycobacterium spp. alters activation and recruitment of several "Ras gene from rat brain" proteins, commonly known as Rab. Mycobacterial phagosomes have a greater and sustained expression of Rab5, Rab11, Rab14 and Rab22a, and lowered or no expression of Rab7, Rab9 and Rab6. This correlates with increased fusion of the phagosomes with early and recycling endosomes acquiring some features of early phagosomes, allowing the bacteria to gain access to nutrients and preventing the activation of anti-mycobacterial mechanisms. The expression of constitutively active mutants of Rab from the early stage endosomes prevents the maturation of phagosomes containing latex beads or heat-inactivated mycobacteria. Silencing of these mutants by interference RNA or dominant negative forms induces the maturation of mycobacterial phagosomes. The mechanisms have not been established by which mycobacteria alter the expression of these GTPases and thereby shift the phagolysosomal maturation. The problem can be explained by alterations in the recruitment of proteins that interact with Rab, such as phosphoinositide 3-kinases and early endosomal antigen 1. Identifying the mechanisms used by Mycobacterium spp. to disrupt the cycle of Rab activation will be essential to understand the pathophysiology of mycobacterial infections and usefully to potential drug targets.

  15. Promoter analysis of TCDD-inducible genes in a thymic epithelial cell line indicates the potential for cell-specific transcription factor crosstalk in the AhR response

    SciTech Connect

    Frericks, Markus; Burgoon, Lyle D.; Zacharewski, Timothy R.; Esser, Charlotte

    2008-10-15

    Activation of the aryl hydrocarbon receptor (AhR{sup 1}) by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) elicits severe immunosuppression accompanied by thymic atrophy. Previous evidence suggests that TCDD targets both thymocytes and thymic epithelial cells. The AhR induces cell-specific changes in gene transcription via binding to the dioxin response element DRE; however, the underlying specificity-mechanisms, in particular with regard to the role of promoter element context, and possible transcription factor crosstalk remain poorly understood. Global gene expression in the cortical thymic epithelial cell line ET at 2, 4, and 6 h following 5 nM TCDD exposure resulted in differential regulation of 201 genes. JASPAR and TRANSFAC mapped the statistically over-represented promoter elements in the regulated genes to specific transcription factor binding sites, suggesting a regulatory role in AhR signaling. Over-represented elements included the xenobiotic response element XRE, NF{kappa}B-Rel, HRE, PPAR{gamma}, GR, PAX-4 and estrogen receptor binding sites. Co-treatment experiments with TCDD and CoCl{sub 2}, to induce hypoxia, or TCDD and 17-{beta}-estradiol (E2) indicated crosstalk between AhR and Hif or ER, in agreement with other experimental models. The computational identification of TFBS and the demonstration of interaction confirm their interactions with AhR signaling and suggest that the other over-represented elements may also be important in the immunosuppressive effects elicited by TCDD. In conclusion, we demonstrated the importance of promoter element cooperation in the shaping of a cell-specific AhR response. Our findings regarding the transcriptional changes in cortical epithelial cells are congruent with the well-known thymotoxic TCDD-phenotype, and useful in new hypothesis generation of the role of cortical TECs in TCDD toxicity.

  16. Altered rest-activity patterns evolve via circadian independent mechanisms in cave adapted balitorid loaches.

    PubMed

    Duboué, Erik R; Borowsky, Richard L

    2012-01-01

    Circadian rhythms and rest homeostasis are independent processes, each regulating important components of rest-activity patterns. Evolutionarily, the two are distinct from one another; total rest time is maintained unaffected even when circadian pacemaker cells are ablated. Throughout the animal kingdom, there exists a huge variation in rest-activity patterns, yet it is unclear how these behaviors have evolved. Here we show that four species of balitorid cavefish have greatly reduced rest times in comparison to rest times of their surface relatives. All four cave species retained biological rhythmicity, and in three of the four there is a pronounced 24-hour rhythm; in the fourth there is an altered rhythmicity of 38-40 hours. Thus, consistent changes in total rest have evolved in these species independent of circadian rhythmicity. Taken together, our data suggest that consistent reduction in total rest times were accomplished evolutionarily through alterations in rest homeostasis. PMID:22348026

  17. Alteration and modulation of protein activity by varying post-translational modification

    DOEpatents

    Thompson, David N.; Reed, David W.; Thompson, Vicki S.; Lacey, Jeffrey A.; Apel, William A.

    2016-07-12

    Embodiments of the invention include methods of altering the enzymatic activity or solubility of an extremophilic enzyme or post-translationally modifying a protein of interest via using isolated or partially purified glycosyltransferases and/or post-translational modification proteins, extracts of cells comprising glycosyltransferases and/or post-translational modification proteins, and/or in cells comprising one or more glycosyltransferases and/or post-translational modification proteins.

  18. Alteration and modulation of protein activity by varying post-translational modification

    DOEpatents

    Thompson, David N; Reed, David W; Thompson, Vicki S; Lacey, Jeffrey A; Apel, William A

    2015-03-03

    Embodiments of the invention include methods of altering the enzymatic activity or solubility of an extremophilic enzyme or post-translationally modifying a protein of interest via using isolated or partially purified glycosyltransferases and/or post-translational modification proteins, extracts of cells comprising glycosyltransferases and/or post-translational modification proteins, and/or in cells comprising one or more glycosyltransferases and/or post-translational modification proteins.

  19. Alterations in neuronal activity in basal ganglia-thalamocortical circuits in the parkinsonian state

    PubMed Central

    Galvan, Adriana; Devergnas, Annaelle; Wichmann, Thomas

    2015-01-01

    In patients with Parkinson’s disease and in animal models of this disorder, neurons in the basal ganglia and related regions in thalamus and cortex show changes that can be recorded by using electrophysiologic single-cell recording techniques, including altered firing rates and patterns, pathologic oscillatory activity and increased inter-neuronal synchronization. In addition, changes in synaptic potentials or in the joint spiking activities of populations of neurons can be monitored as alterations in local field potentials (LFPs), electroencephalograms (EEGs) or electrocorticograms (ECoGs). Most of the mentioned electrophysiologic changes are probably related to the degeneration of diencephalic dopaminergic neurons, leading to dopamine loss in the striatum and other basal ganglia nuclei, although degeneration of non-dopaminergic cell groups may also have a role. The altered electrical activity of the basal ganglia and associated nuclei may contribute to some of the motor signs of the disease. We here review the current knowledge of the electrophysiologic changes at the single cell level, the level of local populations of neural elements, and the level of the entire basal ganglia-thalamocortical network in parkinsonism, and discuss the possible use of this information to optimize treatment approaches to Parkinson’s disease, such as deep brain stimulation (DBS) therapy. PMID:25698937

  20. Characterization testing of a 40 AHR bipolar nickel-hydrogen battery

    NASA Astrophysics Data System (ADS)

    Brewer, Jeffrey C.; Manzo, Michelle A.; Gemeiner, Russel P.

    1989-12-01

    Extensive characterization testing has been done on a second 40 amp-hour (Ahr), 10-cell bipolar nickel-hydrogen (Ni-H2) battery to study the effects of such operating parameters as charge and discharge rates, temperature, and pressure, on capacity, Ahr and watt-hour (Whr) efficiencies, end-of-charge (EOC) and mid-point discharge voltages. Testing to date has produced many interesting results, with the battery performing well throughout all of the test matrix except during the high-rate (5C and 10C) discharges, where poorer than expected results were observed. The exact cause of this poor performance is, as yet, unknown. Small scale 2 x 2 inch battery tests are to be used in studying this problem. Low earth orbit (LEO) cycle life testing at a 40 percent depth of discharge (DOD) and 10 C is scheduled to follow the characterization testing.

  1. Characterization testing of a 40 AHR bipolar nickel-hydrogen battery

    NASA Technical Reports Server (NTRS)

    Brewer, Jeffrey C.; Manzo, Michelle A.; Gemeiner, Russel P.

    1989-01-01

    Extensive characterization testing has been done on a second 40 amp-hour (Ahr), 10-cell bipolar nickel-hydrogen (Ni-H2) battery to study the effects of such operating parameters as charge and discharge rates, temperature, and pressure, on capacity, Ahr and watt-hour (Whr) efficiencies, end-of-charge (EOC) and mid-point discharge voltages. Testing to date has produced many interesting results, with the battery performing well throughout all of the test matrix except during the high-rate (5C and 10C) discharges, where poorer than expected results were observed. The exact cause of this poor performance is, as yet, unknown. Small scale 2 x 2 inch battery tests are to be used in studying this problem. Low earth orbit (LEO) cycle life testing at a 40 percent depth of discharge (DOD) and 10 C is scheduled to follow the characterization testing.

  2. Hemin/G-quadruplex structure and activity alteration induced by magnesium cations.

    PubMed

    Kosman, J; Juskowiak, B

    2016-04-01

    The influence of metal cations on G-quadruplex structure and peroxidase-mimicking DNAzyme activity was investigated. Experiments revealed a significant role of magnesium ion, which in the presence of potassium cation influenced DNAzyme activity. This ability has been associated with alteration of G-quadruplex topology and consequently affinity to bind hemin molecule. It has been demonstrated that G-quadruplex based on PS2.M sequence under these conditions formed parallel topology, which exhibited lower activity than that observed in standard potassium-containing solution. On the other hand DNAzyme/magnesium ion system based on telomeric sequence, which did not undergo significant structural changes, exhibited higher peroxidase activity upon magnesium ion addition. In both cases, the stabilization effect of magnesium cations on G-quadruplex structure was observed. The mechanism of DNAzyme activity alteration by magnesium ion can be explained by its influence on the pKa value of DNAzyme. Magnesium ion decreased pKa for PS2.M based system but increased it for telomeric DNAzyme. Magnesium cation effect on G-quadruplex structure as well as DNAzyme activity is particularly important since this ion is one of the most common metal cations in biological samples.

  3. Alterations in adipocyte adenylate cyclase activity in morbidly obese and formerly morbidly obese humans.

    PubMed

    Martin, L F; Klim, C M; Vannucci, S J; Dixon, L B; Landis, J R; LaNoue, K F

    1990-08-01

    Studies examining animal models of genetic obesity have identified defects in adipocyte hormone-stimulated lipolysis that involve the adenylate cyclase transmembrane signaling system, specifically those components that decrease adenylate cyclase activity. To determine whether obese people demonstrate alterations in adenylate cyclase activity that could contribute to the maintenance of obesity by inhibiting lipolysis, we examined human adipocytes from patients who were lean, obese, or formerly obese. Fat samples were obtained from the lower abdomen of 14 women who were morbidly obese (obese group), from 10 women who were formerly morbidly obese and had lost weight after gastric stapling (postobese group), and from 10 similarly aged women of normal weight (controls). Adipocyte adenylate cyclase activity was determined under ligand-free (no stimulatory or inhibitory influences present), hormone-stimulated (isoproterenol, 10(-6) mmol/L), and maximal (cells stimulated with 10 mumol/L forskolin) conditions by measuring cyclic adenosine monophosphate (cAMP) levels by radioimmunoassay. The activity of adenylate cyclase was significantly different (p less than 0.01) in the three groups. Adipocytes from obese women had lower levels of cyclase activity under both ligand-free (5% vs 16% of maximal) and hormone-stimulated conditions (76% vs 100% of maximal) than adipocytes from normal women. Postobese women had levels of hormone-stimulated cAMP identical to those of normal women but still had abnormal ligand-free levels (under 5%). These results suggest the presence of an alteration in adipocyte adenylate cyclase regulation in morbidly obese women that is not entirely corrected when weight is lost after food intake is reduced by gastric stapling. This alteration in ligand-free cAMP activity may contribute to the development and maintenance of obesity. PMID:2166354

  4. The impacts of altered tropical cyclone activity on climate mitigation strategies

    NASA Astrophysics Data System (ADS)

    Fisk, J. P.; Hurtt, G. C.; LePage, Y.; Patel, P.; Chini, L. P.; Thomson, A. M.; Clarke, L.; Calvin, K. V.; Wise, M.; Chambers, J. Q.; Negron Juarez, R. I.

    2012-12-01

    There is growing evidence that anthropogenic climate change may alter patterns of tropical cyclone frequency, intensity and spatial distribution, which in turn will alter the carbon balance of terrestrial systems in the large regions impacted by these storms. Recent studies project up to a doubling of major storms (Saffir-Simpson Scale 3-5) over the next century. Single large storms have been shown to be capable of causing committed carbon emissions equivalent to the annual U.S. carbon sink. These changes have the potential to affect climate mitigation strategies, most of which rely on maintaining or enhancing the terrestrial carbon sink to restrain the accumulation of atmospheric greenhouse gases. Altered patterns of disturbances and the resulting changes to the carbon balance of terrestrial systems could impact the magnitude of emissions to mitigate, the economic value of ecosystem carbon storage, and thus future land-use patterns, food prices and energy technology. Here we investigate the potential consequences of altered tropical cyclone activity on climate mitigation strategies using a fully integrated model (iED) that links advanced ecological and socio-economic models. The model combines the regional integrated assessment algorithms of the Global Change Assessment Model (GCAM), with the climate- sensitive ecosystem and carbon modeling in the Ecosystem Demography (ED) model, and the land-use mapping algorithms of the Global Land-use Model (GLM). We explore a range of scenarios of altered future tropical cyclone frequency, intensity and spatial pattern, the resulting effects on the terrestrial carbon balance, and the coupled effects on the food and energy sector under a range of future climate mitigation goals.

  5. Memory impairment and alterations in prefrontal cortex gamma band activity following methamphetamine sensitization

    PubMed Central

    Linsenbardt, David N.; Lapish, Christopher C.

    2015-01-01

    Rationale Repeated methamphetamine (MA) use leads to increases in the incentive motivational properties of the drug as well as cognitive impairments. These behavioral alterations persist for some time following abstinence, and neuroadaptations in the structure and function of the prefrontal cortex (PFC) are particularly important for their expression. However, there is a weak understanding of the changes in neural firing and oscillatory activity in the PFC evoked by repeated drug use, thus complicating the development of novel treatment strategies for addiction. Objectives The purpose of the current study was to assess changes in cognitive and brain function following MA sensitization. Methods Sensitization was induced in rats, then temporal and recognition memory were assessed after 1 or 30 days of abstinence. Electrophysiological recordings from the medial PFC were also acquired from rats whereupon simultaneous measures of oscillatory and spiking activity were examined. Results Impaired temporal memory was observed after 1 and 30 days of abstinence. However, recognition memory was only impaired after 1 day of abstinence. An injection of MA profoundly decreased neuronal firing rate and the anesthesia-induced slow oscillation (SO) in both sensitized (SENS) and control (CTRL) rats. Strong correlations were observed between the SO and gamma band power, which was altered in SENS animals. A decrease in the number of neurons phase-locked to the gamma oscillation was also observed in SENS animals. Conclusions The changes observed in PFC function may play an integral role in the expression of the altered behavioral phenotype evoked by MA sensitization. PMID:25572530

  6. Physical activity attenuates age-related biomarker alterations in preclinical AD

    PubMed Central

    Schultz, Stephanie A.; Oh, Jennifer M.; Larson, Jordan; Edwards, Dorothy; Cook, Dane; Koscik, Rebecca; Gallagher, Catherine L.; Dowling, N.M.; Carlsson, Cynthia M.; Bendlin, Barbara B.; LaRue, Asenath; Rowley, Howard A.; Christian, Brad T.; Asthana, Sanjay; Hermann, Bruce P.; Johnson, Sterling C.; Sager, Mark A.

    2014-01-01

    Objective: To examine whether engagement in physical activity might favorably alter the age-dependent evolution of Alzheimer disease (AD)-related brain and cognitive changes in a cohort of at-risk, late-middle-aged adults. Methods: Three hundred seventeen enrollees in the Wisconsin Registry for Alzheimer's Prevention underwent T1 MRI; a subset also underwent 11C-Pittsburgh compound B–PET (n = 186) and 18F-fluorodeoxyglucose–PET (n = 152) imaging. Participants' responses on a self-report measure of current physical activity were used to classify them as either physically active or physically inactive based on American Heart Association guidelines. They also completed a comprehensive neuropsychological battery. Covariate-adjusted regression analyses were used to test whether the adverse effect of age on imaging and cognitive biomarkers was modified by physical activity. Results: There were significant age × physical activity interactions for β-amyloid burden (p = 0.014), glucose metabolism (p = 0.015), and hippocampal volume (p = 0.025) such that, with advancing age, physically active individuals exhibited a lesser degree of biomarker alterations compared with the physically inactive. Similar age × physical activity interactions were also observed on cognitive domains of Immediate Memory (p = 0.042) and Visuospatial Ability (p = 0.016). In addition, the physically active group had higher scores on Speed and Flexibility (p = 0.002) compared with the inactive group. Conclusions: In a middle-aged, at-risk cohort, a physically active lifestyle is associated with an attenuation of the deleterious influence of age on key biomarkers of AD pathophysiology. However, because our observational, cross-sectional design cannot establish causality, randomized controlled trials/longitudinal studies will be necessary for determining whether midlife participation in structured physical exercise forestalls the development of AD and related disorders in later life. PMID:25298312

  7. Human ecstasy (MDMA) polydrug users have altered brain activation during semantic processing

    PubMed Central

    Watkins, Tristan J.; Raj, Vidya; Lee, Junghee; Dietrich, Mary S.; Cao, Aize; Blackford, Jennifer U.; Salomon, Ronald M.; Park, Sohee; Benningfield, Margaret M.; Di Iorio, Christina R.; Cowan, Ronald L.

    2012-01-01

    Rationale Ecstasy (MDMA) polydrug users have verbal memory performance that is statistically significantly lower than comparison control subjects. Studies have correlated long-term MDMA use with altered brain activation in regions that play a role in verbal memory. Objectives The aim of our study was to examine the association of lifetime ecstasy use with semantic memory performance and brain activation in ecstasy polydrug users. Methods 23 abstinent ecstasy polydrug users (age=24.57) and 11 controls (age=22.36) performed a two-part fMRI semantic encoding and recognition task. To isolate brain regions activated during each semantic task, we created statistical activation maps in which brain activation was greater for word stimuli than for non-word stimuli (corrected p<0.05). Results During the encoding phase, ecstasy polydrug users had greater activation during semantic encoding bilaterally in language processing regions, including Brodmann Areas 7, 39, and 40. Of this bilateral activation, signal intensity with a peak T in the right superior parietal lobe was correlated with lifetime ecstasy use (rs=0.43, p=0.042). Behavioral performance did not differ between groups. Conclusions These findings demonstrate that ecstasy polydrug users have increased brain activation during semantic processing. This increase in brain activation in the absence of behavioral deficits suggests that ecstasy polydrug users have reduced cortical efficiency during semantic encoding, possibly secondary to MDMA-induced 5-HT neurotoxicity. Although pre-existing differences cannot be ruled out, this suggests the possibility of a compensatory mechanism allowing ecstasy polydrug users to perform equivalently to controls, providing additional support for an association of altered cerebral neurophysiology with MDMA exposure. PMID:23241648

  8. An Assessment of Technical and Production Risks of Candidate Low-Cost Attitude/Heading Reference Systems(AHRS)

    NASA Technical Reports Server (NTRS)

    Yuchnovicz, Daniel; Burgess, Malcolm; Hammers, William

    1999-01-01

    This report provides an assessment of technical and production risks of candidate low-cost attitude/heading reference systems (AHRS) for use in the Advanced General Aviation Transport Experiments (AGATE) airplanes. A low-cost AHRS is a key component of modem "glass cockpit" flight displays for General Aviation (GA) aircraft. The technical capabilities of several candidate low-cost AHRS were examined and described along with the technical issues involved with using all solid-state components for attitude measurement. An economic model was developed which describes the expected profit, rate of return, and volume requirements for the manufacture of low-cost AHRS for GA aircraft in the 2000 to 2020 time frame. The model is the result of interviews with GA airframe manufacturers, avionics manufacturers and historical analysis of avionics of similar complexity. The model shows that a manufacturer will break even after three years of AHRS production, realizing an 18 percent rate of return (23 percent profit) on an investment of $3.5M over the 20 year period. A start-up production estimate showed costs of $6-12M for a new company to build and certify an AHRS from scratch, considered to be a high-risk proposition, versus $0.25-0.75M for an experienced avionics manufacturer to manufacture a design under license, a low-risk proposition.

  9. Complete denture base assessments using holograms: dimensional alterations after different activation methods

    NASA Astrophysics Data System (ADS)

    Dughir, Ciprian; Popovschi, Ana Maria; Cojocariu, Andreea Codruta; Topala, Florin Ionel; Negrutiu, Meda Lavinia; Sinescu, Cosmin; de Sabata, Aldo; Duma, Virgil-Florin

    2016-03-01

    Holography is a well-developed method with a large range of applications, including dentistry. This study uses holographic methods for the study of total dental prosthesis. The issue is that the transformation of wax denture base in polymethylacrylate causes dimensional alterations and retractions in the final dental constructs. These could cause the failure of the stability of the complete denture in the oral cavity. Thus, the aim of this study is to determine and to compare using holography, total prosthesis obtained using three different manufacturing methods: pressing, injection, and polymerization. Each of the three types of dentures thus produced were recorded over the previously wax complete base holographic plates. The dimensional alterations that appear after using the different activation methods were thus determined. The most significant modification was remarked in the custom press technology, while the smallest variations were detected in the injection alternative.

  10. Altered cognition-related brain activity and interactions with acute pain in migraine

    PubMed Central

    Mathur, Vani A.; Khan, Shariq A.; Keaser, Michael L.; Hubbard, Catherine S.; Goyal, Madhav; Seminowicz, David A.

    2015-01-01

    Little is known about the effect of migraine on neural cognitive networks. However, cognitive dysfunction is increasingly being recognized as a comorbidity of chronic pain. Pain appears to affect cognitive ability and the function of cognitive networks over time, and decrements in cognitive function can exacerbate affective and sensory components of pain. We investigated differences in cognitive processing and pain–cognition interactions between 14 migraine patients and 14 matched healthy controls using an fMRI block-design with two levels of task difficulty and concurrent heat (painful and not painful) stimuli. Across groups, cognitive networks were recruited in response to a difficult cognitive task, and a pain–task interaction was found in the right (contralateral to pain stimulus) posterior insula (pINS), such that activity was modulated by decreasing the thermal pain stimulus or by engaging the difficult cognitive task. Migraine patients had less task-related deactivation within the left dorsolateral prefrontal cortex (DLPFC) and left dorsal anterior midcingulate cortex (aMCC) compared to controls. These regions have been reported to have decreased cortical thickness and cognitive-related deactivation within other pain populations, and are also associated with pain regulation, suggesting that the current findings may reflect altered cognitive function and top-down regulation of pain. During pain conditions, patients had decreased task-related activity, but more widespread task-related reductions in pain-related activity, compared to controls, suggesting cognitive resources may be diverted from task-related to pain-reduction-related processes in migraine. Overall, these findings suggest that migraine is associated with altered cognitive-related neural activity, which may reflect altered pain regulatory processes as well as broader functional restructuring. PMID:25610798

  11. Single nucleotide polymorphisms in the human corticosteroid-binding globulin promoter alter transcriptional activity.

    PubMed

    Li, Yue; Wu, Liang; Lei, JingHui; Zhu, Cheng; Wang, HongMei; Yu, XiaoGuang; Lin, HaiYan

    2012-08-01

    Corticosteroid-binding globulin (CBG) is a high-affinity plasma protein that transports glucocorticoids and progesterone. Others and we have reported non-synonymous single nucleotide polymorphisms (SNPs) that influence CBG production or steroid-binding activity. However, no promoter polymorphisms affecting the transcription of human CBG gene (Cbg) have been reported. In the present study we investigated function implications of six promoter SNPs, including -26 C/G, -54 C/T, -144 G/C, -161 A/G, -205 C/A, and -443/-444 AG/-, five of which are located within the first 205 base pairs of 5'-flanking region and close to the highly conserved footprinted elements, TATA-box, or CCAAT-box. Luciferase reporter assays demonstrated that basal activity of the promoter carrying -54 T or -161 G was significantly enhanced. The first three polymorphisms, -26 C/G, -54 C/T, and -144 G/C located close to the putative hepatic nuclear factor (HNF) 1 binding elements, altered the transactivation effect of HNF1β. We also found a negative promoter response to dexamethasone-activated glucocorticoid receptor (GR) α, although none of the SNPs affected its transrepression function. Our results suggest that human Cbg -26 C/G, -54 C/T, -144 G/C, and -161 A/G promoter polymorphisms alter transcriptional activity, and further studies are awaited to explore their association with physiological and pathological conditions.

  12. Effect of altering starting length and activation timing of muscle on fiber strain and muscle damage.

    PubMed

    Butterfield, Timothy A; Herzog, Walter

    2006-05-01

    Muscle strain injuries are some of the most frequent injuries in sports and command a great deal of attention in an effort to understand their etiology. These injuries may be the culmination of a series of subcellular events accumulated through repetitive lengthening (eccentric) contractions during exercise, and they may be influenced by a variety of variables including fiber strain magnitude, peak joint torque, and starting muscle length. To assess the influence of these variables on muscle injury magnitude in vivo, we measured fiber dynamics and joint torque production during repeated stretch-shortening cycles in the rabbit tibialis anterior muscle, at short and long muscle lengths, while varying the timing of activation before muscle stretch. We found that a muscle subjected to repeated stretch-shortening cycles of constant muscle-tendon unit excursion exhibits significantly different joint torque and fiber strains when the timing of activation or starting muscle length is changed. In particular, measures of fiber strain and muscle injury were significantly increased by altering activation timing and increasing the starting length of the muscle. However, we observed differential effects on peak joint torque during the cyclic stretch-shortening exercise, as increasing the starting length of the muscle did not increase torque production. We conclude that altering activation timing and muscle length before stretch may influence muscle injury by significantly increasing fiber strain magnitude and that fiber dynamics is a more important variable than muscle-tendon unit dynamics and torque production in influencing the magnitude of muscle injury.

  13. Tuning the catalytic properties of lipases immobilized on divinylsulfone activated agarose by altering its nanoenvironment.

    PubMed

    dos Santos, Jose C S; Rueda, Nazzoly; Gonçalves, Luciana R B; Fernandez-Lafuente, Roberto

    2015-09-01

    Lipase from Thermomyces lanuginosus (TLL) and lipase B from Candida antarctica (CALB) have been immobilized on divinylsulfone (DVS) activated agarose beads at pH 10 for 72 h. Then, as a reaction end point, very different nucleophiles have been used to block the support and the effect of the nature of the blocking reagent has been analyzed on the features of the immobilized preparations. The blocking has generally positive effects on enzyme stability in both thermal and organic solvent inactivations. For example, CALB improved 7.5-fold the thermal stability after blocking with imidazole. The effect on enzyme activity was more variable, strongly depending on the substrate and the experimental conditions. Referring to CALB; using p-nitrophenyl butyrate (p-NPB) and methyl phenylacetate, activity always improved by the blocking step, whatever the blocking reagent, while with methyl mandelate or ethyl hexanoate not always the blocking presented a positive effect. Other example is TLL-DVS biocatalyst blocked with Cys. This was more than 8 times more active than the non-blocked preparation and become the most active versus p-NPB at pH 7, the least active versus methyl phenylacetate at pH 5 but the third one most active at pH 9, versus methyl mandelate presented lower activity than the unblocked preparation at pH 5 and versus ethyl hexanoate was the most active at all pH values. That way, enzyme specificity could be strongly altered by this blocking step.

  14. The Secondary Structure of Human Hageman Factor (Factor XII) and its Alteration by Activating Agents

    PubMed Central

    McMillin, Carl R.; Saito, Hidehiko; Ratnoff, Oscar D.; Walton, Alan G.

    1974-01-01

    Hageman factor (factor XII) is activated by exposure to surfaces such as glass or by solutions of certain compounds, notably ellagic acid. Changes in the structure of Hageman factor accompanying activation have been examined in this study by circular dichroism spectroscopy. The spectrum of unactivated Hageman factor in aqueous solutions suggests that its conformation is mainly aperiodic. Various perturbants altered the conformation of Hageman factor in differing ways, demonstrating the sensitivity of Hageman factor to its environment. After activation of Hageman factor with solutions of ellagic acid, a negative trough appeared in the region of the circular dichroism spectrum commonly assigned to tyrosine residues, along with other minor changes in the peptide spectral region. Some of these changes are similar to changes that occurred upon partial neutralization of the basic residues at alkali pH. Activation of Hageman factor by adsorption to quartz surfaces (in an aqueous environment) also produced changes similar to those in the ellagic acid-activated Hageman factor, including the negative ellipticity in the tyrosine region. These observations suggest that the activation process may be related to a change in status of some of the basic amino acid residues, coupled with a specific change in the environment of some tyrosine residues. The importance of these changes during the activation process remains to be determined. The sensitivity of Hageman factor to its environment is consistent with the view that the initiation of clotting by exposure of plasma to appropriate agents is brought about by alterations in the conformation of Hageman factor that occur in the apparent absence of Fletcher factor or other recognized clotting factors. Images PMID:4373492

  15. The bile acid-sensitive ion channel (BASIC) is activated by alterations of its membrane environment.

    PubMed

    Schmidt, Axel; Lenzig, Pia; Oslender-Bujotzek, Adrienne; Kusch, Jana; Lucas, Susana Dias; Gründer, Stefan; Wiemuth, Dominik

    2014-01-01

    The bile acid-sensitive ion channel (BASIC) is a member of the DEG/ENaC family of ion channels. Channels of this family are characterized by a common structure, their physiological functions and modes of activation, however, are diverse. Rat BASIC is expressed in brain, liver and intestinal tract and activated by bile acids. The physiological function of BASIC and its mechanism of bile acid activation remain a puzzle. Here we addressed the question whether amphiphilic bile acids activate BASIC by directly binding to the channel or indirectly by altering the properties of the surrounding membrane. We show that membrane-active substances other than bile acids also affect the activity of BASIC and that activation by bile acids and other membrane-active substances is non-additive, suggesting that BASIC is sensitive for changes in its membrane environment. Furthermore based on results from chimeras between BASIC and ASIC1a, we show that the extracellular and the transmembrane domains are important for membrane sensitivity.

  16. Alterations of Regional Spontaneous Brain Activity and Gray Matter Volume in the Blind

    PubMed Central

    Jiang, Aili; Tian, Jing; Li, Rui; Liu, Yong; Jiang, Tianzi; Qin, Wen; Yu, Chunshui

    2015-01-01

    Visual deprivation can induce alterations of regional spontaneous brain activity (RSBA). However, the effects of onset age of blindness on the RSBA and the association between the alterations of RSBA and brain structure are still unclear in the blind. In this study, we performed resting-state functional and structural magnetic resonance imaging on 50 sighted controls and 91 blind subjects (20 congenitally blind, 27 early blind, and 44 late blind individuals). Compared with the sighted control, we identified increased RSBA in the blind in primary and high-level visual areas and decreased RSBA in brain regions which are ascribed to sensorimotor and salience networks. In contrast, blind subjects exhibited significantly decreased gray matter volume (GMV) in the visual areas, while they exhibited significantly increased GMV in the sensorimotor areas. Moreover, the onset age of blindness was negatively correlated with the GMV of visual areas in blind subjects, whereas it exerted complex influences on the RSBA. Finally, significant negative correlations were shown between RSBA and GMV values. Our results demonstrated system-dependent, inverse alterations in RSBA and GMV after visual deprivation. Furthermore, the onset age of blindness has different effects on the reorganizations in RSBA and GMV. PMID:26568891

  17. Alterations of Regional Spontaneous Brain Activity and Gray Matter Volume in the Blind.

    PubMed

    Jiang, Aili; Tian, Jing; Li, Rui; Liu, Yong; Jiang, Tianzi; Qin, Wen; Yu, Chunshui

    2015-01-01

    Visual deprivation can induce alterations of regional spontaneous brain activity (RSBA). However, the effects of onset age of blindness on the RSBA and the association between the alterations of RSBA and brain structure are still unclear in the blind. In this study, we performed resting-state functional and structural magnetic resonance imaging on 50 sighted controls and 91 blind subjects (20 congenitally blind, 27 early blind, and 44 late blind individuals). Compared with the sighted control, we identified increased RSBA in the blind in primary and high-level visual areas and decreased RSBA in brain regions which are ascribed to sensorimotor and salience networks. In contrast, blind subjects exhibited significantly decreased gray matter volume (GMV) in the visual areas, while they exhibited significantly increased GMV in the sensorimotor areas. Moreover, the onset age of blindness was negatively correlated with the GMV of visual areas in blind subjects, whereas it exerted complex influences on the RSBA. Finally, significant negative correlations were shown between RSBA and GMV values. Our results demonstrated system-dependent, inverse alterations in RSBA and GMV after visual deprivation. Furthermore, the onset age of blindness has different effects on the reorganizations in RSBA and GMV. PMID:26568891

  18. Changes in stomatal function and water use efficiency in potato plants with altered sucrolytic activity.

    PubMed

    Antunes, Werner C; Provart, Nicholas J; Williams, Thomas C R; Loureiro, Marcelo E

    2012-04-01

    As water availability for agriculture decreases, breeding or engineering of crops with improved water use efficiency (WUE) will be necessary. As stomata are responsible for controlling gas exchange across the plant epidermis, metabolic processes influencing solute accumulation in guard cells are potential targets for engineering. In addition to its role as an osmoticum, sucrose breakdown may be required for synthesis of other osmotica or generation of the ATP needed for solute uptake. Thus, alterations in partitioning of sucrose between storage and breakdown may affect stomatal function. In agreement with this hypothesis, potato (Solanum tuberosum) plants expressing an antisense construct targeted against sucrose synthase 3 (SuSy3) exhibited decreased stomatal conductance, a slight reduction in CO(2) fixation and increased WUE. Conversely, plants with increased guard cell acid invertase activity caused by the introduction of the SUC2 gene from yeast had increased stomatal conductance, increased CO(2) fixation and decreased WUE. (14)CO(2) feeding experiments indicated that these effects cannot be attributed to alterations in photosynthetic capacity, and most likely reflect alterations in stomatal function. These results highlight the important role that sucrose breakdown may play in guard cell function and indicate the feasibility of manipulating plant WUE through engineering of guard cell sucrose metabolism.

  19. Alterations in the heart rate and activity rhythms of three orbital astronauts on a space mission.

    PubMed

    Liu, Zhizhen; Wan, Yufeng; Zhang, Lin; Tian, Yu; Lv, Ke; Li, Yinghui; Wang, Chunhui; Chen, Xiaoping; Chen, Shanguang; Guo, Jinhu

    2015-01-01

    Environmental factors in space are dramatically different from those on Earth. The spaceflight environment has been known to influence human physiology and behavior on orbital missions. In this study, we investigated alterations in the diurnal rhythms of activity and heart rate of three Chinese astronauts on a space mission. An analysis of the heart rate data showed a significant decrease in heart rate amplitudes during flight in all three subjects. The heart rate amplitudes of all the three astronauts were significantly dampened during flight, and the minimum as well as the maximum value of heart rate increased after flight. A phase shift in heart rate was observed in one of the three astronauts after flight. These results demonstrate the influence of spaceflight on heart physiology and function. In addition, a significant decrease in body trunk activity and rhythmicity occurred during flight, demonstrating that the spaceflight environment disturbs motion adaptation and diurnal activity rhythms.

  20. Plant adaptation to extreme environments: the example of Cistus salviifolius of an active geothermal alteration field.

    PubMed

    Bartoli, Giacomo; Bottega, Stefania; Forino, Laura M C; Ciccarelli, Daniela; Spanò, Carmelina

    2014-02-01

    Cistus salviifolius is able to colonise one of the most extreme active geothermal alteration fields in terms of both soil acidity and hot temperatures. The analyses of morpho-functional and physiological characters, investigated in leaves of plants growing around fumaroles (G leaves) and in leaves developed by the same plants after transfer into growth chamber under controlled conditions (C leaves) evidenced the main adaptive traits developed by this pioneer plant in a stressful environment. These traits involved leaf shape and thickness, mesophyll compactness, stomatal and trichome densities, chloroplast size. Changes of functional and physiological traits concerned dry matter content, peroxide and lipid peroxidation, leaf area, relative water and pigment contents. A higher reducing power and antioxidant enzymatic activity were typical of G leaves. Though the high levels of stress parameters, G leaves showed stress-induced specific morphogenic and physiological responses putatively involved in their surviving in active geothermal habitats.

  1. Alterations in the heart rate and activity rhythms of three orbital astronauts on a space mission.

    PubMed

    Liu, Zhizhen; Wan, Yufeng; Zhang, Lin; Tian, Yu; Lv, Ke; Li, Yinghui; Wang, Chunhui; Chen, Xiaoping; Chen, Shanguang; Guo, Jinhu

    2015-01-01

    Environmental factors in space are dramatically different from those on Earth. The spaceflight environment has been known to influence human physiology and behavior on orbital missions. In this study, we investigated alterations in the diurnal rhythms of activity and heart rate of three Chinese astronauts on a space mission. An analysis of the heart rate data showed a significant decrease in heart rate amplitudes during flight in all three subjects. The heart rate amplitudes of all the three astronauts were significantly dampened during flight, and the minimum as well as the maximum value of heart rate increased after flight. A phase shift in heart rate was observed in one of the three astronauts after flight. These results demonstrate the influence of spaceflight on heart physiology and function. In addition, a significant decrease in body trunk activity and rhythmicity occurred during flight, demonstrating that the spaceflight environment disturbs motion adaptation and diurnal activity rhythms. PMID:26177621

  2. Altered Theta Oscillations and Aberrant Cortical Excitatory Activity in the 5XFAD Model of Alzheimer's Disease

    PubMed Central

    Siwek, Magdalena Elisabeth; Müller, Ralf; Henseler, Christina; Trog, Astrid; Lundt, Andreas; Wormuth, Carola; Broich, Karl; Weiergräber, Marco; Papazoglou, Anna

    2015-01-01

    Alzheimer's disease (AD) is an age-related neurodegenerative disorder characterized by impairment of memory function. The 5XFAD mouse model was analyzed and compared with wild-type (WT) controls for aberrant cortical excitability and hippocampal theta oscillations by using simultaneous video-electroencephalogram (EEG) monitoring. Seizure staging revealed that 5XFAD mice exhibited cortical hyperexcitability whereas controls did not. In addition, 5XFAD mice displayed a significant increase in hippocampal theta activity from the light to dark phase during nonmotor activity. We also observed a reduction in mean theta frequency in 5XFAD mice compared to controls that was again most prominent during nonmotor activity. Transcriptome analysis of hippocampal probes and subsequent qPCR validation revealed an upregulation of Plcd4 that might be indicative of enhanced muscarinic signalling. Our results suggest that 5XFAD mice exhibit altered cortical excitability, hippocampal dysrhythmicity, and potential changes in muscarinic signaling. PMID:25922768

  3. Plant adaptation to extreme environments: the example of Cistus salviifolius of an active geothermal alteration field.

    PubMed

    Bartoli, Giacomo; Bottega, Stefania; Forino, Laura M C; Ciccarelli, Daniela; Spanò, Carmelina

    2014-02-01

    Cistus salviifolius is able to colonise one of the most extreme active geothermal alteration fields in terms of both soil acidity and hot temperatures. The analyses of morpho-functional and physiological characters, investigated in leaves of plants growing around fumaroles (G leaves) and in leaves developed by the same plants after transfer into growth chamber under controlled conditions (C leaves) evidenced the main adaptive traits developed by this pioneer plant in a stressful environment. These traits involved leaf shape and thickness, mesophyll compactness, stomatal and trichome densities, chloroplast size. Changes of functional and physiological traits concerned dry matter content, peroxide and lipid peroxidation, leaf area, relative water and pigment contents. A higher reducing power and antioxidant enzymatic activity were typical of G leaves. Though the high levels of stress parameters, G leaves showed stress-induced specific morphogenic and physiological responses putatively involved in their surviving in active geothermal habitats. PMID:24581804

  4. Alterations of white matter integrity related to motor activity in schizophrenia.

    PubMed

    Walther, Sebastian; Federspiel, Andrea; Horn, Helge; Razavi, Nadja; Wiest, Roland; Dierks, Thomas; Strik, Werner; Müller, Thomas J

    2011-06-01

    Altered structural connectivity is a key finding in schizophrenia, but the meaning of white matter alterations for behavior is rarely studied. In healthy subjects, motor activity correlated with white matter integrity in motor tracts. To explore the relation of motor activity and fractional anisotropy (FA) in schizophrenia, we investigated 19 schizophrenia patients and 24 healthy control subjects using Diffusion Tensor Imaging (DTI) and actigraphy on the same day. Schizophrenia patients had lower activity levels (AL). In both groups linear relations of AL and FA were detected in several brain regions. Schizophrenia patients had lower FA values in prefrontal and left temporal clusters. Furthermore, using a general linear model, we found linear negative associations of FA and AL underneath the right supplemental motor area (SMA), the right precentral gyrus and posterior cingulum in patients. This effect within the SMA was not seen in controls. This association in schizophrenia patients may contribute to the well known dysfunctions of motor control. Thus, structural disconnectivity could lead to disturbed motor behavior in schizophrenia.

  5. Altered spontaneous neural activity in the occipital face area reflects behavioral deficits in developmental prosopagnosia.

    PubMed

    Zhao, Yuanfang; Li, Jingguang; Liu, Xiqin; Song, Yiying; Wang, Ruosi; Yang, Zetian; Liu, Jia

    2016-08-01

    Individuals with developmental prosopagnosia (DP) exhibit severe difficulties in recognizing faces and to a lesser extent, also exhibit difficulties in recognizing non-face objects. We used fMRI to investigate whether these behavioral deficits could be accounted for by altered spontaneous neural activity. Two aspects of spontaneous neural activity were measured: the intensity of neural activity in a voxel indexed by the fractional amplitude of spontaneous low-frequency fluctuations (fALFF), and the connectivity of a voxel to neighboring voxels indexed by regional homogeneity (ReHo). Compared with normal adults, both the fALFF and ReHo values within the right occipital face area (rOFA) were significantly reduced in DP subjects. Follow-up studies on the normal adults revealed that these two measures indicated further functional division of labor within the rOFA. The fALFF in the rOFA was positively correlated with behavioral performance in recognition of non-face objects, whereas ReHo in the rOFA was positively correlated with processing of faces. When considered together, the altered fALFF and ReHo within the same region (rOFA) may account for the comorbid deficits in both face and object recognition in DPs, whereas the functional division of labor in these two measures helps to explain the relative independency of deficits in face recognition and object recognition in DP. PMID:27475965

  6. The Crowded Sea: Incorporating Multiple Marine Activities in Conservation Plans Can Significantly Alter Spatial Priorities

    PubMed Central

    Mazor, Tessa; Possingham, Hugh P.; Edelist, Dori; Brokovich, Eran; Kark, Salit

    2014-01-01

    Successful implementation of marine conservation plans is largely inhibited by inadequate consideration of the broader social and economic context within which conservation operates. Marine waters and their biodiversity are shared by a host of stakeholders, such as commercial fishers, recreational users and offshore developers. Hence, to improve implementation success of conservation plans, we must incorporate other marine activities while explicitly examining trade-offs that may be required. In this study, we test how the inclusion of multiple marine activities can shape conservation plans. We used the entire Mediterranean territorial waters of Israel as a case study to compare four planning scenarios with increasing levels of complexity, where additional zones, threats and activities were added (e.g., commercial fisheries, hydrocarbon exploration interests, aquaculture, and shipping lanes). We applied the marine zoning decision support tool Marxan to each planning scenario and tested a) the ability of each scenario to reach biodiversity targets, b) the change in opportunity cost and c) the alteration of spatial conservation priorities. We found that by including increasing numbers of marine activities and zones in the planning process, greater compromises are required to reach conservation objectives. Complex plans with more activities incurred greater opportunity cost and did not reach biodiversity targets as easily as simplified plans with less marine activities. We discovered that including hydrocarbon data in the planning process significantly alters spatial priorities. For the territorial waters of Israel we found that in order to protect at least 10% of the range of 166 marine biodiversity features there would be a loss of ∼15% of annual commercial fishery revenue and ∼5% of prospective hydrocarbon revenue. This case study follows an illustrated framework for adopting a transparent systematic process to balance biodiversity goals and economic

  7. Anabolic steroids alter the physiological activity of aggression circuits in the lateral anterior hypothalamus.

    PubMed

    Morrison, T R; Sikes, R W; Melloni, R H

    2016-02-19

    Syrian hamsters exposed to anabolic/androgenic steroids (AAS) during adolescence consistently show increased aggressive behavior across studies. Although the behavioral and anatomical profiles of AAS-induced alterations have been well characterized, there is a lack of data describing physiological changes that accompany these alterations. For instance, behavioral pharmacology and neuroanatomical studies show that AAS-induced changes in the vasopressin (AVP) neural system within the latero-anterior hypothalamus (LAH) interact with the serotonin (5HT) and dopamine (DA) systems to modulate aggression. To characterize the electrophysiological profile of the AAS aggression circuit, we recorded LAH neurons in adolescent male hamsters in vivo and microiontophoretically applied agonists and antagonists of aggressive behavior. The interspike interval (ISI) of neurons from AAS-treated animals correlated positively with aggressive behaviors, and adolescent AAS exposure altered parameters of activity in regular firing neurons while also changing the proportion of neuron types (i.e., bursting, regular, irregular). AAS-treated animals had more responsive neurons that were excited by AVP application, while cells from control animals showed the opposite effect and were predominantly inhibited by AVP. Both DA D2 antagonists and 5HT increased the firing frequency of AVP-responsive cells from AAS animals and dual application of AVP and D2 antagonists doubled the excitatory effect of AVP or D2 antagonist administration alone. These data suggest that multiple DA circuits in the LAH modulate AAS-induced aggressive responding. More broadly, these data show that multiple neurochemical interactions at the neurophysiological level are altered by adolescent AAS exposure.

  8. Anabolic steroids alter the physiological activity of aggression circuits in the lateral anterior hypothalamus.

    PubMed

    Morrison, T R; Sikes, R W; Melloni, R H

    2016-02-19

    Syrian hamsters exposed to anabolic/androgenic steroids (AAS) during adolescence consistently show increased aggressive behavior across studies. Although the behavioral and anatomical profiles of AAS-induced alterations have been well characterized, there is a lack of data describing physiological changes that accompany these alterations. For instance, behavioral pharmacology and neuroanatomical studies show that AAS-induced changes in the vasopressin (AVP) neural system within the latero-anterior hypothalamus (LAH) interact with the serotonin (5HT) and dopamine (DA) systems to modulate aggression. To characterize the electrophysiological profile of the AAS aggression circuit, we recorded LAH neurons in adolescent male hamsters in vivo and microiontophoretically applied agonists and antagonists of aggressive behavior. The interspike interval (ISI) of neurons from AAS-treated animals correlated positively with aggressive behaviors, and adolescent AAS exposure altered parameters of activity in regular firing neurons while also changing the proportion of neuron types (i.e., bursting, regular, irregular). AAS-treated animals had more responsive neurons that were excited by AVP application, while cells from control animals showed the opposite effect and were predominantly inhibited by AVP. Both DA D2 antagonists and 5HT increased the firing frequency of AVP-responsive cells from AAS animals and dual application of AVP and D2 antagonists doubled the excitatory effect of AVP or D2 antagonist administration alone. These data suggest that multiple DA circuits in the LAH modulate AAS-induced aggressive responding. More broadly, these data show that multiple neurochemical interactions at the neurophysiological level are altered by adolescent AAS exposure. PMID:26691962

  9. Non-prenylatable, cytosolic Rac1 alters neurite outgrowth while retaining the ability to be activated.

    PubMed

    Reddy, Jairus M; Samuel, Filsy G; McConnell, Jordan A; Reddy, Cristina P; Beck, Brian W; Hynds, DiAnna L

    2015-03-01

    Rac1 is an important regulator of axon extension, cell migration and actin reorganization. Like all Rho guanine triphosphatases (GTPases), Rac1 is targeted to the membrane by the addition of a geranylgeranyl moiety, an action thought to result in Rac1 guanosine triphosphate (GTP) binding. However, the role that Rac1 localization plays in its activation (GTP loading) and subsequent activation of effectors is not completely clear. To address this, we developed a non-prenylatable emerald green fluorescent protein (EmGFP)-Rac1 fusion protein (EmGFP-Rac1(C189A)) and assessed how expressing this construct affected neurite outgrowth, Rac1 localization and activation in neuroblastoma cells. Expression of EmGFP-Rac1(C189A) increased localization to the cytosol and induced cell clustering while increasing neurite initiation. EmGFP-Rac1(C189A) expression also increased Rac1 activation in the cytosol, compared to cells expressing wild-type Rac1 (EmGFP-Rac1). These results suggest that activation of Rac1 may not require plasma membrane localization, potentially leading to differential activation of cytosolic signaling pathways that alter cell morphology. Understanding the consequences of differential localization and activation of Rho GTPases, including Rac1, could lead to new therapeutic targets for treating neurological disorders. PMID:25479592

  10. Alterations in Daytime and Nighttime Activity in Piglets after Focal and Diffuse Brain Injury.

    PubMed

    Olson, Emily; Badder, Carlie; Sullivan, Sarah; Smith, Colin; Propert, Kathleen; Margulies, Susan S

    2016-04-15

    We have developed and implemented a noninvasive, objective neurofunctional assessment for evaluating the sustained effects of traumatic brain injury (TBI) in piglets with both diffuse and focal injury types. Derived from commercial actigraphy methods in humans, this assessment continuously monitors the day/night activity of piglets using close-fitting jackets equipped with tri-axial accelerometers to monitor movements of the thorax. Acceleration metrics were correlated (N = 7 naïve piglets) with video images to define values associated with a range of activities, from recumbancy (rest) to running. Both focal (N = 8) and diffuse brain injury (N = 9) produced alterations in activity that were significant 4 days post-TBI. Compared to shams (N = 6) who acclimated to the animal facility 4 days after an anesthesia experience by blurring the distinction between day and night activity, post-TBI time-matched animals had larger fractions of inactive periods during the daytime than nighttime, and larger fractions of active time in the night were spent in high activity (e.g., constant walking, intermittent running) than during the day. These persistent disturbances in rest and activity are similar to those observed in human adults and children post-TBI, establishing actigraphy as a translational metric, used in both humans and large animals, for assessment of injury severity, progressions, and intervention. PMID:26414329

  11. The LRRC26 Protein Selectively Alters the Efficacy of BK Channel Activators

    PubMed Central

    Almassy, Janos

    2012-01-01

    Large conductance, Ca2+-activated K channel proteins are involved in a wide range of physiological activities, so there is considerable interest in the pharmacology of large conductance calcium-activated K (BK) channels. One potent activator of BK channels is mallotoxin (MTX), which produces a very large hyperpolarizing shift of the voltage gating of heterologously expressed BK channels and causes a dramatic increase in the activity of BK channels in human smooth muscle cells. However, we found that MTX shifted the steady-state activation of BK channels in native parotid acinar cells by only 6 mV. This was not because the parotid BK isoform (parSlo) is inherently insensitive to MTX as MTX shifted the activation of heterologously expressed parSlo channels by 70 mV. Even though MTX had a minimal effect on steady-state activation of parotid BK channels, it produced an approximate 2-fold speeding of the channel-gating kinetics. The BK channels in parotid acinar cells have a much more hyperpolarized voltage activation range than BK channels in most other cell types. We found that this is probably attributable to an accessory protein, LRRC26, which is expressed in parotid glands: expressed parSlo + LRRC26 channels were resistant to the actions of MTX. Another class of BK activators is the benzimidazalones that includes 1,3-dihydro-1-(2-hydroxy-5-(trifluoromethyl)phenyl)-5-(trifluoromethyl)-2H-benzimidazol-2-one (NS-1619). Although the LRRC26 accessory protein strongly inhibited the ability of MTX to activate BK channels, we found that it had only a small effect on the action of NS-1619 on BK channels. Thus, the LRRC26 BK channel accessory protein selectively alters the pharmacology of BK channels. PMID:21984254

  12. Nanomolar Bifenthrin Alters Synchronous Ca2+ Oscillations and Cortical Neuron Development Independent of Sodium Channel Activity

    PubMed Central

    Cao, Zhengyu; Cui, Yanjun; Nguyen, Hai M.; Jenkins, David Paul; Wulff, Heike

    2014-01-01

    Bifenthrin, a relatively stable type I pyrethroid that causes tremors and impairs motor activity in rodents, is broadly used. We investigated whether nanomolar bifenthrin alters synchronous Ca2+ oscillations (SCOs) necessary for activity-dependent dendritic development. Primary mouse cortical neurons were cultured 8 or 9 days in vitro (DIV), loaded with the Ca2+ indicator Fluo-4, and imaged using a Fluorescence Imaging Plate Reader Tetra. Acute exposure to bifenthrin rapidly increased the frequency of SCOs by 2.7-fold (EC50 = 58 nM) and decreased SCO amplitude by 36%. Changes in SCO properties were independent of modifications in voltage-gated sodium channels since 100 nM bifenthrin had no effect on the whole-cell Na+ current, nor did it influence neuronal resting membrane potential. The L-type Ca2+ channel blocker nifedipine failed to ameliorate bifenthrin-triggered SCO activity. By contrast, the metabotropic glutamate receptor (mGluR)5 antagonist MPEP [2-methyl-6-(phenylethynyl)pyridine] normalized bifenthrin-triggered increase in SCO frequency without altering baseline SCO activity, indicating that bifenthrin amplifies mGluR5 signaling independent of Na+ channel modification. Competitive [AP-5; (−)-2-amino-5-phosphonopentanoic acid] and noncompetitive (dizocilpine, or MK-801 [(5S,10R)-(+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imine maleate]) N-methyl-d-aspartate antagonists partially decreased both basal and bifenthrin-triggered SCO frequency increase. Bifenthrin-modified SCO rapidly enhanced the phosphorylation of cAMP response element–binding protein (CREB). Subacute (48 hours) exposure to bifenthrin commencing 2 DIV–enhanced neurite outgrowth and persistently increased SCO frequency and reduced SCO amplitude. Bifenthrin-stimulated neurite outgrowth and CREB phosphorylation were dependent on mGluR5 activity since MPEP normalized both responses. Collectively these data identify a new mechanism by which bifenthrin potently alters Ca2

  13. Xeno-sensing activity of the aryl hydrocarbon receptor in human pluripotent stem cell-derived hepatocyte-like cells

    PubMed Central

    Kim, Hye-Min; Kim, Ji-Woo; Choi, Youngjun; Chun, Hang-Suk; Im, Ilkyun; Han, Yong-Mahn; Song, Chang-Woo; Yoon, Seokjoo; Park, Han-Jin

    2016-01-01

    Although hepatocyte-like cells derived from human pluripotent stem cells (hPSC-HLCs) are considered a promising model for predicting hepatotoxicity, their application has been restricted because of the low activity of drug metabolizing enzymes (DMEs). Here we found that the low expression of xenobiotic receptors (constitutive androstane receptor, CAR; and pregnane X receptor, PXR) contributes to the low activity of DMEs in hPSC-HLCs. Most CAR- and PXR-regulated DMEs and transporters were transcriptionally down-regulated in hPSC-HLC. Transcriptional expression of CAR and PXR was highly repressed in hPSC-HLCs, whereas mRNA levels of aryl hydrocarbon receptor (AHR) were comparable to those of adult liver. Furthermore, ligand-induced transcriptional activation was observed only at AHR in hPSC-HLCs. Bisulfite sequencing analysis demonstrated that promoter hypermethylation of CAR and PXR was associated with diminished transcriptional activity in hPSC-HLCs. Treatment with AHR-selective ligands increased the transcription of AHR-dependent target genes by direct AHR-DNA binding at the xenobiotic response element. In addition, an antagonist of AHR significantly inhibited AHR-dependent target gene expression. Thus, AHR may function intrinsically as a xenosensor as well as a ligand-dependent transcription factor in hPSC-HLCs. Our results indicate that hPSC-HLCs can be used to screen toxic substances related to AHR signaling and to identify potential AHR-targeted therapeutics. PMID:26899675

  14. Altered Activation of Protein Kinase PKR and Enhanced Apoptosis in Dystonia Cells Carrying a Mutation in PKR Activator Protein PACT*

    PubMed Central

    Vaughn, Lauren S; Bragg, D. Cristopher; Sharma, Nutan; Camargos, Sarah; Cardoso, Francisco; Patel, Rekha C

    2015-01-01

    PACT is a stress-modulated activator of the interferon-induced double-stranded RNA-activated protein kinase (PKR). Stress-induced phosphorylation of PACT is essential for PACT's association with PKR leading to PKR activation. PKR activation leads to phosphorylation of translation initiation factor eIF2α inhibition of protein synthesis and apoptosis. A recessively inherited form of early-onset dystonia DYT16 has been recently identified to arise due to a homozygous missense mutation P222L in PACT. To examine if the mutant P222L protein alters the stress-response pathway, we examined the ability of mutant P222L to interact with and activate PKR. Our results indicate that the substitution mutant P222L activates PKR more robustly and for longer duration albeit with slower kinetics in response to the endoplasmic reticulum stress. In addition, the affinity of PACT-PACT and PACT-PKR interactions is enhanced in dystonia patient lymphoblasts, thereby leading to intensified PKR activation and enhanced cellular death. P222L mutation also changes the affinity of PACT-TRBP interaction after cellular stress, thereby offering a mechanism for the delayed PKR activation in response to stress. Our results demonstrate the impact of a dystonia-causing substitution mutation on stress-induced cellular apoptosis. PMID:26231208

  15. Altered kynurenine pathway metabolism in autism: Implication for immune-induced glutamatergic activity.

    PubMed

    Lim, Chai K; Essa, Musthafa M; de Paula Martins, Roberta; Lovejoy, David B; Bilgin, Ayse A; Waly, Mostafa I; Al-Farsi, Yahya M; Al-Sharbati, Marwan; Al-Shaffae, Mohammed A; Guillemin, Gilles J

    2016-06-01

    Dysfunction of the serotoninergic and glutamatergic systems is implicated in the pathogenesis of autism spectrum disorder (ASD) together with various neuroinflammatory mediators. As the kynurenine pathway (KP) of tryptophan degradation is activated in neuroinflammatory states, we hypothesized that there may be a link between inflammation in ASD and enhanced KP activation resulting in reduced serotonin synthesis from tryptophan and production of KP metabolites capable of modulating glutamatergic activity. A cross-sectional study of 15 different Omani families with newly diagnosed children with ASD (n = 15) and their age-matched healthy siblings (n = 12) was designed. Immunological profile and the KP metabolic signature were characterized in the study participants. Our data indicated that there were alterations to the KP in ASD. Specifically, increased production of the downstream metabolite, quinolinic acid, which is capable of enhancing glutamatergic neurotransmission was noted. Correlation studies also demonstrated that the presence of inflammation induced KP activation in ASD. Until now, previous studies have failed to establish a link between inflammation, glutamatergic activity, and the KP. Our findings also suggest that increased quinolinic acid may be linked to 16p11.2 mutations leading to abnormal glutamatergic activity associated with ASD pathogenesis and may help rationalize the efficacy of sulforaphane treatment in ASD. Autism Res 2016, 9: 621-631. © 2015 International Society for Autism Research, Wiley Periodicals, Inc.

  16. TCDD dysregulation of 13 AHR-target genes in rat liver

    SciTech Connect

    Watson, John D.; Prokopec, Stephenie D.; Smith, Ashley B.; Okey, Allan B.; Pohjanvirta, Raimo; Boutros, Paul C.

    2014-02-01

    Despite several decades of research, the complete mechanism by which 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and other xenobiotic agonists of the aryl hydrocarbon receptor (AHR) cause toxicity remains unclear. While it has been shown that the AHR is required for all major manifestations of toxicity, the specific downstream changes involved in the development of toxic phenotypes remain unknown. Here we examine a panel of 13 genes that are AHR-regulated in many species and tissues. We profiled their hepatic mRNA abundances in two rat strains with very different sensitivities to TCDD: the TCDD-sensitive Long–Evans (Turku/AB; L–E) and the TCDD-resistant Han/Wistar (Kuopio; H/W). We evaluated doses ranging from 0 to 3000 μg/kg at 19 h after TCDD exposure and time points ranging from 1.5 to 384 h after exposure to 100 μg/kg TCDD. Twelve of 13 genes responded to TCDD in at least one strain, and seven of these showed statistically significant inter-strain differences in the time course analysis (Aldh3a1, Cyp1a2, Cyp1b1, Cyp2a1, Fmo1, Nfe2l2 and Nqo1). Cyp2s1 did not respond to TCDD in either rat strain. Five genes exhibited biphasic responses to TCDD insult (Ahrr, Aldh3a1, Cyp1b1, Nfe2l2 and Nqo1), suggesting a secondary event, such as association with additional transcriptional modulators. Of the 12 genes that responded to TCDD during the dose–response analysis, none had an ED{sub 50} equivalent to that of Cyp1a1, the most sensitive gene in this study, while nine genes responded to doses at least 10–100 fold higher, in at least one strain (Ahrr (L–E), Aldh3a1 (both), Cyp1a2 (both), Cyp1b1 (both), Cyp2a1 (L–E), Inmt (both), Nfe2l2 (L–E), Nqo1 (L–E) and Tiparp (both)). These data shed new light on the association of the AHR target genes with TCDD toxicity, and in particular the seven genes exhibiting strain-specific differences represent strong candidate mediators of Type-II toxicities. - Highlights: • NanoString measured hepatic mRNA molecules

  17. Maternal caffeine exposure alters neuromotor development and hippocampus acetylcholinesterase activity in rat offspring.

    PubMed

    Souza, Ana Claudia; Souza, Andressa; Medeiros, Liciane Fernandes; De Oliveira, Carla; Scarabelot, Vanessa Leal; Da Silva, Rosane Souza; Bogo, Mauricio Reis; Capiotti, Katiucia Marques; Kist, Luiza Wilges; Bonan, Carla D; Caumo, Wolnei; Torres, Iraci L S

    2015-01-21

    The objective of this study was to evaluate the effects of maternal caffeine intake on the neuromotor development of rat offspring and on acetylcholine degradation and acetylcholinesterase (AChE) expression in the hippocampus of 14-day-old infant rats. Rat dams were treated with caffeine (0.3g/L) throughout gestation and lactation until the pups were 14 days old. The pups were divided into three groups: (1) control, (2) caffeine, and (3) washout caffeine. The washout group received a caffeine solution until the seventh postnatal day (P7). Righting reflex (RR) and negative geotaxis (NG) were assessed to evaluate postural parameters as an index of neuromotor reflexes. An open-field (OF) test was conducted to assess locomotor and exploratory activities as well as anxiety-like behaviors. Caffeine treatment increased both RR and NG latency times. In the OF test, the caffeine group had fewer outer crossings and reduced locomotion compared to control, while the washout group showed increased inner crossings in relation to the other groups and fewer rearings only in comparison to the control group. We found decreased AChE activity in the caffeine group compared to the other groups, with no alteration in AChE transcriptional regulation. Chronic maternal exposure to caffeine promotes important alterations in neuromotor development. These results highlight the ability of maternal caffeine intake to interfere with cholinergic neurotransmission during brain development.

  18. Altered spontaneous activity in antisocial personality disorder revealed by regional homogeneity.

    PubMed

    Tang, Yan; Liu, Wangyong; Chen, Jingang; Liao, Jian; Hu, Dewen; Wang, Wei

    2013-08-01

    There is increasing evidence that antisocial personality disorder (ASPD) stems from brain abnormalities. However, there are only a few studies investigating brain structure in ASPD. The aim of this study was to find regional coherence abnormalities in resting-state functional MRI of ASPD. Thirty-two ASPD individuals and 34 controls underwent a resting-state functional MRI scan. The regional homogeneity (ReHo) approach was used to examine whether ASPD was related to alterations in resting-state neural activity. Support vector machine discriminant analysis was used to evaluate the sensitivity/specificity characteristics of the ReHo index in discriminating between the ASPD individuals and controls. The results showed that, compared with controls, ASPD individuals show lower ReHo in the right cerebellum posterior lobe (Crus1) and the right middle frontal gyrus, as well as higher ReHo in the right middle occipital gyrus (BA 19), left inferior temporal gyrus (BA 37), and right inferior occipital gyrus (cuneus, BA 18). All alternation regions reported a predictive accuracy above 70%. To our knowledge, this study was the first to study the change in regional activity coherence in the resting brain of ASPD individuals. These results not only elucidated the pathological mechanism of ASPD from a resting-state functional viewpoint but also showed that these alterations in ReHo may serve as potential markers for the detection of ASPD.

  19. Maternal caffeine exposure alters neuromotor development and hippocampus acetylcholinesterase activity in rat offspring.

    PubMed

    Souza, Ana Claudia; Souza, Andressa; Medeiros, Liciane Fernandes; De Oliveira, Carla; Scarabelot, Vanessa Leal; Da Silva, Rosane Souza; Bogo, Mauricio Reis; Capiotti, Katiucia Marques; Kist, Luiza Wilges; Bonan, Carla D; Caumo, Wolnei; Torres, Iraci L S

    2015-01-21

    The objective of this study was to evaluate the effects of maternal caffeine intake on the neuromotor development of rat offspring and on acetylcholine degradation and acetylcholinesterase (AChE) expression in the hippocampus of 14-day-old infant rats. Rat dams were treated with caffeine (0.3g/L) throughout gestation and lactation until the pups were 14 days old. The pups were divided into three groups: (1) control, (2) caffeine, and (3) washout caffeine. The washout group received a caffeine solution until the seventh postnatal day (P7). Righting reflex (RR) and negative geotaxis (NG) were assessed to evaluate postural parameters as an index of neuromotor reflexes. An open-field (OF) test was conducted to assess locomotor and exploratory activities as well as anxiety-like behaviors. Caffeine treatment increased both RR and NG latency times. In the OF test, the caffeine group had fewer outer crossings and reduced locomotion compared to control, while the washout group showed increased inner crossings in relation to the other groups and fewer rearings only in comparison to the control group. We found decreased AChE activity in the caffeine group compared to the other groups, with no alteration in AChE transcriptional regulation. Chronic maternal exposure to caffeine promotes important alterations in neuromotor development. These results highlight the ability of maternal caffeine intake to interfere with cholinergic neurotransmission during brain development. PMID:25451122

  20. Methylated pentavalent arsenic metabolites are bifunctional inducers, as they induce cytochrome P450 1A1 and NAD(P)H:quinone oxidoreductase through AhR- and Nrf2-dependent mechanisms.

    PubMed

    Anwar-Mohamed, Anwar; Elshenawy, Osama H; Soshilov, Anatoly A; Denison, Michael S; Chris Le, X; Klotz, Lars-Oliver; El-Kadi, Ayman O S

    2014-02-01

    Activation of the aryl hydrocarbon receptor (AhR) ultimately leads to the induction of the carcinogen-activating enzyme cytochrome P450 1A1 (CYP1A1), and activation of the nuclear factor-erythroid 2 p45-related factor 2 (Nrf2) in addition to the AhR pathway induces the expression of the NADP(H):quinone oxidoreductase (NQO1). Therefore, the aim of this study was to examine the effect of As(III) pentavalent metabolites, MMA(V), DMA(V), and TMA(V), on AhR and Nrf2 activation and on the expression of their prototypical downstream targets CYP1A1 and NQO1, respectively. Our results showed that treatment of HepG2 cells with MMA(V), DMA(V), or TMA(V) in the absence and presence of 2,3,7,8-tetrachlorodibenzo-p-dioxin or sulforaphane significantly induced both CYP1A1 and NQO1 at the mRNA, protein, and catalytic activity levels. Furthermore, these metabolites increased the AhR-dependent XRE-driven and the Nrf2-dependent ARE-driven luciferase reporter activities, which coincided with increased nuclear accumulation of both transcription factors. However, none of these metabolites were shown to be AhR ligands. The induction of CYP1A1 by these metabolites seems to be ligand-independent, possibly through a decrease in HSP90 protein expression levels. The metabolites also increased ROS production, which was significantly higher than that produced by As(III). Upon knockdown of AhR and Nrf2 the MMA(V)-, DMA(V)-, and TMA(V)-mediated induction of both CYP1A1 and NQO1 proteins was significantly decreased. In conclusion, this study demonstrates for the first time that methylated pentavalent arsenic metabolites are bifunctional inducers, as they increase CYP1A1 by activating the AhR/XRE signaling pathway and they increase NQO1 by activating the Nrf2/ARE signaling pathway in addition to the AhR/XRE pathway.

  1. Alteration of PON1 activity in adult and childhood obesity and its relation to adipokine levels.

    PubMed

    Seres, Ildikó; Bajnok, László; Harangi, Mariann; Sztanek, Ferenc; Koncsos, Peter; Paragh, György

    2010-01-01

    Obesity as a pathogenic disorder is a predisposing factor for cardiovascular diseases and shows an increasing incidence in the industrialized countries. Adipokines such as leptin, adiponectin and resistin have a great impact on the development of atherosclerosis in obesity. Elevated levels of leptin have been found to be atherogenic whereas decreased levels of adiponectin have been proved to be anti-atherogenic in recent studies. The exact role of resistin in the process of atherosclerosis has so far remained uncertain and controversial. In our recent work, we studied the alteration in human paraoxonase-1 (PON1) activity and adipokine levels; furthermore, we also aimed at identifying the potential correlation between these parameters in this metabolic disorder. We investigated the above-mentioned parameters both in adults and in children, with regard to the emerging role of childhood obesity and to get a clearer view of these factors during a whole lifetime. Investigating the adult population with a broad range of body mass index (BMI) we found significantly increased leptin and significantly decreased adiponectin and resistin levels and PON1 activity in the obese group compared to the lean controls. Adiponectin and resistin levels showed significantly positive correlation, while leptin and BMI showed significantly negative correlation with PON1 activity. Our findings were similar in childhood obesity: leptin showed significantly negative correlation, while adiponectin showed significantly positive correlation with PON1 activity. We found gender differences in the univariate correlations of leptin and adiponectin levels with PON1 activity in the adult population. In multiple regression analysis, adiponectin proved to be an independent factor of PON1 activity both in childhood and adult obesity, furthermore thiobarbituric acid-reactive substances (TBARS) also proved to be an independent predictor of the enzyme in adults, reflecting the important role of oxidative

  2. Epigenetic alteration to activate Bmp2-Smad signaling in Raf-induced senescence

    PubMed Central

    Fujimoto, Mai; Mano, Yasunobu; Anai, Motonobu; Yamamoto, Shogo; Fukuyo, Masaki; Aburatani, Hiroyuki; Kaneda, Atsushi

    2016-01-01

    AIM: To investigate epigenomic and gene expression alterations during cellular senescence induced by oncogenic Raf. METHODS: Cellular senescence was induced into mouse embryonic fibroblasts (MEFs) by infecting retrovirus to express oncogenic Raf (RafV600E). RNA was collected from RafV600E cells as well as MEFs without infection and MEFs with mock infection, and a genome-wide gene expression analysis was performed using microarray. The epigenomic status for active H3K4me3 and repressive H3K27me3 histone marks was analyzed by chromatin immunoprecipitation-sequencing for RafV600E cells on day 7 and for MEFs without infection. These data for Raf-induced senescence were compared with data for Ras-induced senescence that were obtained in our previous study. Gene knockdown and overexpression were done by retrovirus infection. RESULTS: Although the expression of some genes including secreted factors was specifically altered in either Ras- or Raf-induced senescence, many genes showed similar alteration pattern in Raf- and Ras-induced senescence. A total of 841 commonly upregulated 841 genes and 573 commonly downregulated genes showed a significant enrichment of genes related to signal and secreted proteins, suggesting the importance of alterations in secreted factors. Bmp2, a secreted protein to activate Bmp2-Smad signaling, was highly upregulated with gain of H3K4me3 and loss of H3K27me3 during Raf-induced senescence, as previously detected in Ras-induced senescence, and the knockdown of Bmp2 by shRNA lead to escape from Raf-induced senescence. Bmp2-Smad inhibitor Smad6 was strongly repressed with H3K4me3 loss in Raf-induced senescence, as detected in Ras-induced senescence, and senescence was also bypassed by Smad6 induction in Raf-activated cells. Different from Ras-induced senescence, however, gain of H3K27me3 did not occur in the Smad6 promoter region during Raf-induced senescence. When comparing genome-wide alteration between Ras- and Raf-induced senescence, genes

  3. Altered cortico-basal ganglia motor pathways reflect reduced volitional motor activity in schizophrenia.

    PubMed

    Bracht, Tobias; Schnell, Susanne; Federspiel, Andrea; Razavi, Nadja; Horn, Helge; Strik, Werner; Wiest, Roland; Dierks, Thomas; Müller, Thomas J; Walther, Sebastian

    2013-02-01

    Little is known about the neurobiology of hypokinesia in schizophrenia. Therefore, the aim of this study was to investigate alterations of white matter motor pathways in schizophrenia and to relate our findings to objectively measured motor activity. We examined 21 schizophrenia patients and 21 healthy controls using diffusion tensor imaging and actigraphy. We applied a probabilistic fibre tracking approach to investigate pathways connecting the dorsolateral prefrontal cortex (dlPFC), the rostral anterior cingulate cortex (rACC), the pre-supplementary motor area (pre-SMA), the supplementary motor area proper (SMA-proper), the primary motor cortex (M1), the caudate nucleus, the striatum, the pallidum and the thalamus. Schizophrenia patients had lower activity levels than controls. In schizophrenia we found higher probability indices forming part of a bundle of interest (PIBI) in pathways connecting rACC, pre-SMA and SMA-proper as well as in pathways connecting M1 and pre-SMA with caudate nucleus, putamen, pallidum and thalamus and a reduced spatial extension of motor pathways in schizophrenia. There was a positive correlation between PIBI and activity level in the right pre-SMA-pallidum and the left M1-thalamus connection in healthy controls, and in the left pre-SMA-SMA-proper pathway in schizophrenia. Our results point to reduced volitional motor activity and altered motor pathway organisation in schizophrenia. The identified associations between the amount of movement and structural connectivity of motor pathways suggest dysfunction of cortico-basal ganglia pathways in the pathophysiology of hypokinesia in schizophrenia. Schizophrenia patients may use cortical pathways involving the supplementary motor area to compensate for basal ganglia dysfunction.

  4. Vitamin D3 alters microglia immune activation by an IL-10 dependent SOCS3 mechanism.

    PubMed

    Boontanrart, Mandy; Hall, Samuel D; Spanier, Justin A; Hayes, Colleen E; Olson, Julie K

    2016-03-15

    Microglia become activated immune cells during infection or disease in the central nervous system (CNS). However, the mechanisms that downregulate activated microglia to prevent immune-mediated damage are not completely understood. Vitamin D3 has been suggested to have immunomodulatory affects, and high levels of vitamin D3 have been correlated with a decreased risk for developing some neurological diseases. Recent studies have demonstrated the synthesis of active vitamin D3, 1,25-dihydroxyvitamin D3, within the CNS, but its cellular source and neuroprotective actions remain unknown. Therefore, we wanted to determine whether microglia can respond to vitamin D3 and whether vitamin D3 alters immune activation of microglia. We have previously shown that microglia become activated by IFNγ or LPS or by infection with virus to express pro-inflammatory cytokines, chemokines, and effector molecules. In this study, activated microglia increased the expression of the vitamin D receptor and Cyp27b1, which encodes the enzyme for converting vitamin D3 into its active form, thereby enhancing their responsiveness to vitamin D3. Most importantly, the activated microglia exposed to vitamin D3 had reduced expression of pro-inflammatory cytokines, IL-6, IL-12, and TNFα, and increased expression of IL-10. The reduction in pro-inflammatory cytokines was dependent on IL-10 induction of suppressor of cytokine signaling-3 (SOCS3). Therefore, vitamin D3 increases the expression of IL-10 creating a feedback loop via SOCS3 that downregulates the pro-inflammatory immune response by activated microglia which would likewise prevent immune mediated damage in the CNS. PMID:26943970

  5. Vitamin D3 alters microglia immune activation by an IL-10 dependent SOCS3 mechanism.

    PubMed

    Boontanrart, Mandy; Hall, Samuel D; Spanier, Justin A; Hayes, Colleen E; Olson, Julie K

    2016-03-15

    Microglia become activated immune cells during infection or disease in the central nervous system (CNS). However, the mechanisms that downregulate activated microglia to prevent immune-mediated damage are not completely understood. Vitamin D3 has been suggested to have immunomodulatory affects, and high levels of vitamin D3 have been correlated with a decreased risk for developing some neurological diseases. Recent studies have demonstrated the synthesis of active vitamin D3, 1,25-dihydroxyvitamin D3, within the CNS, but its cellular source and neuroprotective actions remain unknown. Therefore, we wanted to determine whether microglia can respond to vitamin D3 and whether vitamin D3 alters immune activation of microglia. We have previously shown that microglia become activated by IFNγ or LPS or by infection with virus to express pro-inflammatory cytokines, chemokines, and effector molecules. In this study, activated microglia increased the expression of the vitamin D receptor and Cyp27b1, which encodes the enzyme for converting vitamin D3 into its active form, thereby enhancing their responsiveness to vitamin D3. Most importantly, the activated microglia exposed to vitamin D3 had reduced expression of pro-inflammatory cytokines, IL-6, IL-12, and TNFα, and increased expression of IL-10. The reduction in pro-inflammatory cytokines was dependent on IL-10 induction of suppressor of cytokine signaling-3 (SOCS3). Therefore, vitamin D3 increases the expression of IL-10 creating a feedback loop via SOCS3 that downregulates the pro-inflammatory immune response by activated microglia which would likewise prevent immune mediated damage in the CNS.

  6. Chronic Social Stress in Puberty Alters Appetitive Male Sexual Behavior and Neural Metabolic Activity

    PubMed Central

    Bastida, Christel C.; Puga, Frank; Gonzalez-Lima, Francisco; Jennings, Kimberly J.; Wommack, Joel C.; Delville, Yvon

    2014-01-01

    Repeated social subjugation in early puberty lowers testosterone levels. We used hamsters to investigate the effects of social subjugation on male sexual behavior and metabolic activity within neural systems controlling social and motivational behaviors. Subjugated animals were exposed daily to aggressive adult males in early puberty for postnatal days 28 to 42, while control animals were placed in empty clean cages. On postnatal day 45, they were tested for male sexual behavior in the presence of receptive female. Alternatively, they were tested for mate choice after placement at the base of a Y-maze containing a sexually receptive female in one tip of the maze and an ovariectomized one on the other. Social subjugation did not affect the capacity to mate with receptive females. Although control animals were fast to approach females and preferred ovariectomized individuals, subjugated animals stayed away from them and showed no preference. Cytochrome oxidase activity was reduced within the preoptic area and ventral tegmental area in subjugated hamsters. In addition, the correlation of metabolic activity of these areas with the bed nucleus of the stria terminalis and anterior parietal cortex changed significantly from positive in controls to negative in subjugated animals. These data show that at mid-puberty, while male hamsters are capable of mating, their appetitive sexual behavior is not fully mature and this aspect of male sexual behavior is responsive to social subjugation. Furthermore, metabolic activity and coordination of activity in brain areas related to sexual behavior and motivation was altered by social subjugation. PMID:24852486

  7. Altered resting-state functional activity in posttraumatic stress disorder: A quantitative meta-analysis

    PubMed Central

    Wang, Ting; Liu, Jia; Zhang, Junran; Zhan, Wang; Li, Lei; Wu, Min; Huang, Hua; Zhu, Hongyan; Kemp, Graham J.; Gong, Qiyong

    2016-01-01

    Many functional neuroimaging studies have reported differential patterns of spontaneous brain activity in posttraumatic stress disorder (PTSD), but the findings are inconsistent and have not so far been quantitatively reviewed. The present study set out to determine consistent, specific regional brain activity alterations in PTSD, using the Effect Size Signed Differential Mapping technique to conduct a quantitative meta-analysis of resting-state functional neuroimaging studies of PTSD that used either a non-trauma (NTC) or a trauma-exposed (TEC) comparison control group. Fifteen functional neuroimaging studies were included, comparing 286 PTSDs, 203 TECs and 155 NTCs. Compared with NTC, PTSD patients showed hyperactivity in the right anterior insula and bilateral cerebellum, and hypoactivity in the dorsal medial prefrontal cortex (mPFC); compared with TEC, PTSD showed hyperactivity in the ventral mPFC. The pooled meta-analysis showed hypoactivity in the posterior insula, superior temporal, and Heschl’s gyrus in PTSD. Additionally, subgroup meta-analysis (non-medicated subjects vs. NTC) identified abnormal activation in the prefrontal-limbic system. In meta-regression analyses, mean illness duration was positively associated with activity in the right cerebellum (PTSD vs. NTC), and illness severity was negatively associated with activity in the right lingual gyrus (PTSD vs. TEC). PMID:27251865

  8. Sustained Treatment with Insulin Detemir in Mice Alters Brain Activity and Locomotion

    PubMed Central

    Sartorius, Tina; Hennige, Anita M.; Fritsche, Andreas; Häring, Hans-Ulrich

    2016-01-01

    Aims Recent studies have identified unique brain effects of insulin detemir (Levemir®). Due to its pharmacologic properties, insulin detemir may reach higher concentrations in the brain than regular insulin. This might explain the observed increased brain stimulation after acute insulin detemir application but it remained unclear whether chronic insulin detemir treatment causes alterations in brain activity as a consequence of overstimulation. Methods In mice, we examined insulin detemir’s prolonged brain exposure by continuous subcutaneous (s.c.) application using either micro-osmotic pumps or daily s.c. injections and performed continuous radiotelemetric electrocorticography and locomotion recordings. Results Acute intracerebroventricular injection of insulin detemir activated cortical and locomotor activity significantly more than regular insulin in equimolar doses (0.94 and 5.63 mU in total), suggesting an enhanced acute impact on brain networks. However, given continuously s.c., insulin detemir significantly reduced cortical activity (theta: 21.3±6.1% vs. 73.0±8.1%, P<0.001) and failed to maintain locomotion, while regular insulin resulted in an increase of both parameters. Conclusions The data suggest that permanently-increased insulin detemir levels in the brain convert its hyperstimulatory effects and finally mediate impairments in brain activity and locomotion. This observation might be considered when human studies with insulin detemir are designed to target the brain in order to optimize treatment regimens. PMID:27589235

  9. Regulation and activity of secretory leukoprotease inhibitor (SLPI) is altered in smokers.

    PubMed

    Meyer, Megan; Bauer, Rebecca N; Letang, Blanche D; Brighton, Luisa; Thompson, Elizabeth; Simmen, Rosalia C M; Bonner, James; Jaspers, Ilona

    2014-02-01

    A hallmark of cigarette smoking is a shift in the protease/antiprotease balance, in favor of protease activity. However, it has recently been shown that smokers have increased expression of a key antiprotease, secretory leukoprotease inhibitor (SLPI), yet the mechanisms involved in SLPI transcriptional regulation and functional activity of SLPI remain unclear. We examined SLPI mRNA and protein secretion in differentiated nasal epithelial cells (NECs) and nasal lavage fluid (NLF) from nonsmokers and smokers and demonstrated that SLPI expression is increased in NECs and NLF from smokers. Transcriptional regulation of SLPI expression was confirmed using SLPI promoter reporter assays followed by chromatin immunoprecipitation. The role of STAT1 in regulating SLPI expression was further elucidated using WT and stat1(-/-) mice. Our data demonstrate that STAT1 regulates SLPI transcription in epithelial cells and slpi protein in the lungs of mice. Additionally, we reveal that NECs from smokers have increased STAT1 mRNA/protein expression. Finally, we demonstrate that SLPI contained in the nasal mucosa of smokers is proteolytically cleaved but retains functional activity against neutrophil elastase. These results demonstrate that smoking enhances expression of SLPI in NECs in vitro and in vivo, and that this response is regulated by STAT1. In addition, despite posttranslational cleavage of SLPI, antiprotease activity against neutrophil elastase is enhanced in smokers. Together, our findings show that SLPI regulation and activity is altered in the nasal mucosa of smokers, which could have broad implications in the context of respiratory inflammation and infection.

  10. Evaluation of Potential Clinical Surrogate Markers of a Trauma Induced Alteration of Clotting Factor Activities

    PubMed Central

    Payas, Arzu; Schoeneberg, Carsten; Wegner, Alexander; Kauther, Max Daniel; Lendemans, Sven

    2016-01-01

    Objective. The aim of this study was to identify routinely available clinical surrogate markers for potential clotting factor alterations following multiple trauma. Methods. In 68 patients admitted directly from the scene of the accident, all soluble clotting factors were analyzed and clinical data was collected prospectively. Ten healthy subjects served as control group. Results. Patients showed reduced activities of clotting factors II, V, VII, and X and calcium levels (all P < 0.0001 to 0.01). Levels of hemoglobin and base deficit correlated moderately to highly with the activities of a number of clotting factors. Nonsurvivors and patients who needed preclinical intubation or hemostatic therapy showed significantly reduced factor activities at admission. In contrast, factor VIII activity was markedly elevated after injury in general (P < 0.0001), but reduced in nonsurvivors (P < 0.05). Conclusions. Multiple trauma causes an early reduction of the activities of nearly all soluble clotting factors in general. Initial hemoglobin and, with certain qualifications, base deficit levels demonstrated a potential value in detecting those underlying clotting factor deficiencies. Nevertheless, their role as triggers of a hemostatic therapy as well as the observed response of factor VIII to multiple trauma and also its potential prognostic value needs further evaluation. PMID:27433474

  11. Psychoneuroendocrine immunology: perception of stress can alter body temperature and natural killer cell activity.

    PubMed

    Hiramoto, R N; Solvason, H B; Hsueh, C M; Rogers, C F; Demissie, S; Hiramoto, N S; Gauthier, D K; Lorden, J F; Ghanta, V K

    1999-01-01

    Psychoimmunology has been credited with using the mind as a way to alter immunity. The problem with this concept is that many of the current psychoimmunology techniques in use are aimed at alleviating stress effects on the immune system rather than at direct augmentation of immunity by the brain. Studies in animals provide a model that permits us to approach the difficulties associated with gaining an understanding of the CNS-immune system connection. A particular advantage of using animals over humans is that psychological and social contributions play a less prominent role for animals than for human subjects, since the animals are all inbred and reared under identical controlled conditions. If the insightful information provided by animal studies is correct, then psychotherapy for the treatment of diseases might be made more effective if some aspect of this knowledge is included in the design of the treatment. We emphasize conditioning as a regimen and an acceptable way to train the brain to remember an output pathway to raise immunity. We propose that a specific drug or perception (mild stress, represented by rotation, total body heating or handling) could substitute and kindle the same output pathway without the need for conditioning. If this view is correct, then instead of using conditioning, it may be possible to use an antigen to activate desired immune cells, and substitute a drug or an external environmental sensory stimulus (perception) to energize the output pathway to these cells. Alternatively, monitoring alterations of body temperature in response to a drug or perception might allow us to follow how effectively the brain is performing in altering immunity. Studies with animals suggest that there are alternative ways to use the mind to raise natural or acquired immunity in man.

  12. The aryl hydrocarbon receptor and glucocorticoid receptor interact to activate human metallothionein 2A

    SciTech Connect

    Sato, Shoko; Shirakawa, Hitoshi; Tomita, Shuhei; Tohkin, Masahiro; Gonzalez, Frank J.; Komai, Michio

    2013-11-15

    Although the aryl hydrocarbon receptor (AHR) and glucocorticoid receptor (GR) play essential roles in mammalian development, stress responses, and other physiological events, crosstalk between these receptors has been the subject of much debate. Metallothioneins are classic glucocorticoid-inducible genes that were reported to increase upon treatment with AHR agonists in rodent tissues and cultured human cells. In this study, the mechanism of human metallothionein 2A (MT2A) gene transcription activation by AHR was investigated. Cotreatment with 3-methylcholanthrene and dexamethasone, agonists of AHR and GR respectively, synergistically increased MT2A mRNA levels in HepG2 cells. MT2A induction was suppressed by RNA interference against AHR or GR. Coimmunoprecipitation experiments revealed a physical interaction between AHR and GR proteins. Moreover, chromatin immunoprecipitation assays indicated that AHR was recruited to the glucocorticoid response element in the MT2A promoter. Thus, we provide a novel mechanism whereby AHR modulates expression of human MT2A via the glucocorticoid response element and protein–protein interactions with GR. - Highlights: • Aryl hydrocarbon receptor forms a complex with glucocorticoid receptor in cells. • Human metallothionein gene is regulated by the AHR and GR interaction. • AHR–GR complex binds to glucocorticoid response element in metallothionein gene. • We demonstrated a novel transcriptional mechanism via AHR and GR interaction.

  13. Magnesium impacts myosin V motor activity by altering key conformational changes in the mechanochemical cycle.

    PubMed

    Trivedi, Darshan V; Muretta, Joseph M; Swenson, Anja M; Thomas, David D; Yengo, Christopher M

    2013-07-01

    We investigated how magnesium (Mg) impacts key conformational changes during the ADP binding/release steps in myosin V and how these alterations impact the actomyosin mechanochemical cycle. The conformation of the nucleotide binding pocket was examined with our established FRET system in which myosin V labeled with FlAsH in the upper 50 kDa domain participates in energy transfer with mant labeled nucleotides. We examined the maximum actin-activated ATPase activity of MV FlAsH at a range of free Mg concentrations (0.1-9 mM) and found that the highest activity occurs at low Mg (0.1-0.3 mM), while there is a 50-60% reduction in activity at high Mg (3-9 mM). The motor activity examined with the in vitro motility assay followed a similar Mg-dependence, and the trend was similar with dimeric myosin V. Transient kinetic FRET studies of mantdADP binding/release from actomyosin V FlAsH demonstrate that the transition between the weak and strong actomyosin.ADP states is coupled to movement of the upper 50 kDa domain and is dependent on Mg with the strong state stabilized by Mg. We find that the kinetics of the upper 50 kDa conformational change monitored by FRET correlates well with the ATPase and motility results over a wide range of Mg concentrations. Our results suggest the conformation of the upper 50 kDa domain is highly dynamic in the Mg free actomyosin.ADP state, which is in agreement with ADP binding being entropy driven in the absence of Mg. Overall, our results demonstrate that Mg is a key factor in coupling the nucleotide- and actin-binding regions. In addition, Mg concentrations in the physiological range can alter the structural transition that limits ADP dissociation from actomyosin V, which explains the impact of Mg on actin-activated ATPase activity and in vitro motility.

  14. Altered Skeletal Muscle Lipase Expression and Activity Contribute to Insulin Resistance in Humans

    PubMed Central

    Badin, Pierre-Marie; Louche, Katie; Mairal, Aline; Liebisch, Gerhard; Schmitz, Gerd; Rustan, Arild C.; Smith, Steven R.; Langin, Dominique; Moro, Cedric

    2011-01-01

    OBJECTIVE Insulin resistance is associated with elevated content of skeletal muscle lipids, including triacylglycerols (TAGs) and diacylglycerols (DAGs). DAGs are by-products of lipolysis consecutive to TAG hydrolysis by adipose triglyceride lipase (ATGL) and are subsequently hydrolyzed by hormone-sensitive lipase (HSL). We hypothesized that an imbalance of ATGL relative to HSL (expression or activity) may contribute to DAG accumulation and insulin resistance. RESEARCH DESIGN AND METHODS We first measured lipase expression in vastus lateralis biopsies of young lean (n = 9), young obese (n = 9), and obese-matched type 2 diabetic (n = 8) subjects. We next investigated in vitro in human primary myotubes the impact of altered lipase expression/activity on lipid content and insulin signaling. RESULTS Muscle ATGL protein was negatively associated with whole-body insulin sensitivity in our population (r = −0.55, P = 0.005), whereas muscle HSL protein was reduced in obese subjects. We next showed that adenovirus-mediated ATGL overexpression in human primary myotubes induced DAG and ceramide accumulation. ATGL overexpression reduced insulin-stimulated glycogen synthesis (−30%, P < 0.05) and disrupted insulin signaling at Ser1101 of the insulin receptor substrate-1 and downstream Akt activation at Ser473. These defects were fully rescued by nonselective protein kinase C inhibition or concomitant HSL overexpression to restore a proper lipolytic balance. We show that selective HSL inhibition induces DAG accumulation and insulin resistance. CONCLUSIONS Altogether, the data indicate that altered ATGL and HSL expression in skeletal muscle could promote DAG accumulation and disrupt insulin signaling and action. Targeting skeletal muscle lipases may constitute an interesting strategy to improve insulin sensitivity in obesity and type 2 diabetes. PMID:21498783

  15. Leptin in nucleus of the solitary tract alters the cardiovascular responses to aortic baroreceptor activation.

    PubMed

    Ciriello, John

    2013-06-01

    Recent data suggests that neurons expressing the long form of the leptin receptor form at least two distinct groups within the caudal nucleus of the solitary tract (NTS): a group within the lateral NTS (Slt) and one within the medial (Sm) and gelantinosa (Sg) NTS. Discrete injections of leptin into Sm and Sg, a region that receives chemoreceptor input, elicit increases in arterial pressure (AP) and renal sympathetic nerve activity (RSNA). However, the effect of microinjections of leptin into Slt, a region that receives baroreceptor input is unknown. Experiments were done in the urethane-chloralose anesthetized, paralyzed and artificially ventilated Wistar or Zucker obese rat to determine leptin's effect in Slt on heart rate (HR), AP and RSNA during electrical stimulation of the aortic depressor nerve (ADN). Depressor sites within Slt were first identified by the microinjection of l-glutamate (Glu; 0.25M; 10nl) followed by leptin microinjections. In the Wistar rat leptin microinjection (50ng; 20nl) into depressor sites within the lateral Slt elicited increases in HR and RSNA, but no changes in AP. Additionally, leptin injections into Slt prior to Glu injections at the same site or to stimulation of the ADN were found to attenuate the decreases in HR, AP and RSNA to both the Glu injection and ADN stimulation. In Zucker obese rats, leptin injections into NTS depressor sites did not elicit cardiovascular responses, nor altered the cardiovascular responses elicited by stimulation of ADN. Those data suggest that leptin acts at the level of NTS to alter the activity of neurons that mediate the cardiovascular responses to activation of the aortic baroreceptor reflex. PMID:23535030

  16. Leptin in nucleus of the solitary tract alters the cardiovascular responses to aortic baroreceptor activation.

    PubMed

    Ciriello, John

    2013-06-01

    Recent data suggests that neurons expressing the long form of the leptin receptor form at least two distinct groups within the caudal nucleus of the solitary tract (NTS): a group within the lateral NTS (Slt) and one within the medial (Sm) and gelantinosa (Sg) NTS. Discrete injections of leptin into Sm and Sg, a region that receives chemoreceptor input, elicit increases in arterial pressure (AP) and renal sympathetic nerve activity (RSNA). However, the effect of microinjections of leptin into Slt, a region that receives baroreceptor input is unknown. Experiments were done in the urethane-chloralose anesthetized, paralyzed and artificially ventilated Wistar or Zucker obese rat to determine leptin's effect in Slt on heart rate (HR), AP and RSNA during electrical stimulation of the aortic depressor nerve (ADN). Depressor sites within Slt were first identified by the microinjection of l-glutamate (Glu; 0.25M; 10nl) followed by leptin microinjections. In the Wistar rat leptin microinjection (50ng; 20nl) into depressor sites within the lateral Slt elicited increases in HR and RSNA, but no changes in AP. Additionally, leptin injections into Slt prior to Glu injections at the same site or to stimulation of the ADN were found to attenuate the decreases in HR, AP and RSNA to both the Glu injection and ADN stimulation. In Zucker obese rats, leptin injections into NTS depressor sites did not elicit cardiovascular responses, nor altered the cardiovascular responses elicited by stimulation of ADN. Those data suggest that leptin acts at the level of NTS to alter the activity of neurons that mediate the cardiovascular responses to activation of the aortic baroreceptor reflex.

  17. Antiandrogenic activity of extracts of diesel exhaust particles emitted from diesel-engine truck under different engine loads and speeds.

    PubMed

    Okamura, Kazumasa; Kizu, Ryoichi; Toriba, Akira; Murahashi, Tsuyoshi; Mizokami, Atsushi; Burnstein, Kerry L; Klinge, Carolyn M; Hayakawa, Kazuichi

    2004-02-15

    To clarify the alteration of androgenic and antiandrogenic activities by diesel engine conditions, we collected diesel exhaust particles (DEP) samples emitted from a diesel-engine truck under different conditions of engine loads and vehicle speeds, and DEP extract (DEPE) samples were prepared from each. The androgenic and antiandrogenic activities of the DEPE samples were examined using a prostate specific antigen (PSA) promoter-luciferase reporter gene assay in PC3/AR human prostate cancer cells. While all DEPE samples did not exhibit androgenic effects, the antiandrogenic effects were enhanced by higher engine load but not by higher vehicle speed. In this study, significant correlations between antiandrogenic and aryl hydrocarbon receptor (AhR) agonistic activities were demonstrated in PC3/AR cells by 16 polycyclic aromatic compounds and beta-naphthoflavone. Yeast two-hybrid assay and cytochrome P450 (CYP) 1A1 promoter-luciferase reporter gene assay showed that the antiandrogenic constituents acting as androgen receptor (AR) antagonists and AhR agonists were increased by only the higher engine load. In conclusion, the antiandrogenic effects of DEPE samples were enhanced by a higher engine load which resulted in DEPC samples with elevated AhR agonistic and AR antagonistic activities.

  18. Alterations in cardiac sarcolemmal Ca/sup 2 +/ pump activity during diabetes mellitus

    SciTech Connect

    Heyliger, C.E.; Prakash, A.; McNeill, J.

    1987-03-01

    Diabetes mellitus is frequently associated with a primary cardiomyopathy. The mechanisms responsible for this heart disease are not clear, but an alteration in myocardial Ca/sup 2 +/ transport is believed to be involved in its development. Even though sarcolemma plays a crucial role in cellular Ca/sup 2 +/ transport, little appears to be known about its Ca/sup 2 +/ transporting capability in the diabetic myocardium. In this regard, the authors have examined the status of the cardiac sarcolemmal Ca/sup 2 +/ pump during diabetes mellitus. Purified sarcolemmal membranes were isolated from male Wistar diabetic rat hearts 8 wk after streptozotocin injection. Ca/sup 2 +/ pump activity assessed by measuring its Ca/sup 2 +/-stimulated adenosine triphosphatase and Ca/sup 2 +/-uptake ability in the absence and presence of calmodulin was significantly depressed in the diabetic myocardium relative to controls. These results did not appear to have been influenced by the minimal sarcoplasmic reticular and mitochondrial contamination of this membrane preparation. Hence, it appears that the sarcolemmal Ca/sup 2 +/ pump is defective in the diabetic myocardium and may be involved in the altered Ca/sup 2 +/ transport of the heart during diabetes mellitus.

  19. Trimethyloxonium modification of batrachotoxin-activated Na channels alters functionally important protein residues.

    PubMed Central

    Cherbavaz, D B

    1995-01-01

    The extracellular side of single batrachotoxin-activated voltage-dependent Na channels isolated from rat skeletal muscle membranes incorporated into neutral planar lipid bilayers were treated in situ with the carboxyl methylating reagent, trimethyloxonium (TMO). These experiments were designed to determine whether TMO alters Na channel function by a general through-space electrostatic mechanism or by methylating specific carboxyl groups essential to channel function. TMO modification reduced single-channel conductance by decreasing the maximal turnover rate. Modification increased channel selectivity for sodium ions relative to potassium ions as measured under biionic conditions. TMO modification increased the mu-conotoxin (muCTX) off-rate by three orders of magnitude. Modification did not alter the muCTX on-rate at low ionic strength or Na channel voltage-dependent gating characteristics. These data demonstrate that TMO does not act via a general electrostatic mechanism. Instead, TMO targets protein residues specifically involved in ion conduction, ion selectivity, and muCTX binding. These data support the hypothesis that muCTX blocks open-channel current by physically obstructing the ion channel pore. PMID:7787022

  20. Dynamic alterations in Hippo signaling pathway and YAP activation during liver regeneration.

    PubMed

    Grijalva, James L; Huizenga, Megan; Mueller, Kaly; Rodriguez, Steven; Brazzo, Joseph; Camargo, Fernando; Sadri-Vakili, Ghazaleh; Vakili, Khashayar

    2014-07-15

    The Hippo signaling pathway has been implicated in mammalian organ size regulation and tumor suppression. Specifically, the Hippo pathway plays a critical role regulating the activity of transcriptional coactivator Yes-associated protein (YAP), which modulates a proliferative transcriptional program. Recent investigations have demonstrated that while this pathway is activated in quiescent livers, its inhibition leads to liver overgrowth and tumorigenesis. However, the role of the Hippo pathway during the natural process of liver regeneration remains unknown. Here we investigated alterations in the Hippo signaling pathway and YAP activation during liver regeneration using a 70% partial hepatectomy (PH) rat model. Our results indicate an increase in YAP activation by 1 day following PH as demonstrated by increased YAP nuclear localization and increased YAP target gene expression. Investigation of the Hippo pathway revealed a decrease in the activation of core kinases Mst1/2 by 1 day as well as Lats1/2 and its adapter protein Mob1 by 3 days following PH. Evaluation of liver-to-body weight ratios indicated that the liver reaches its near normal size by 7 days following PH, which correlated with a return to baseline YAP nuclear levels and target gene expression. Additionally, when liver size was restored, Mst1/2 kinase activation returned to levels observed in quiescent livers indicating reactivation of the Hippo signaling pathway. These findings illustrate the dynamic changes in the Hippo signaling pathway and YAP activation during liver regeneration, which stabilize when the liver-to-body weight ratio reaches homeostatic levels.

  1. Acrylamide alters glycogen content and enzyme activities in the liver of juvenile rat.

    PubMed

    Kovac, Renata; Rajkovic, Vesna; Koledin, Ivana; Matavulj, Milica

    2015-10-01

    Acrylamide (AA) is spontaneously formed in carbohydrate-rich food during high-temperature processing. It is neurotoxic and potentially cancer causing chemical. Its harmful effects on the liver, especially in a young organism, are still to be elucidated. The study aimed to examine main liver histology, its glycogen content and enzyme activities in juvenile rats treated with 25 or 50mg/kg bw of AA for 3 weeks. Liver samples were fixed in formalin, routinely processed for paraffin embedding, sectioning and histochemical staining. Examination of haematoxylin and eosin (H&E)-stained sections showed an increase in the volume of hepatocytes, their nuclei and cytoplasm in both AA-treated groups compared to the control. In Periodic acid-Schiff (PAS)-stained sections in low-dose group was noticed glycogen reduction, while in high-dose group was present its accumulation compared to the control, respectively. Serum analysis showed increased activity of aspartate aminotransferase (AST), and decreased activity of alanine aminotransferase (ALT) in both AA-treated groups, while the activity of alkaline phosphatase (ALP) was increased in low-dose, but decreased in high-dose group compared to the control, respectively. Present results suggest a prominent hepatotoxic potential of AA which might alter the microstructural features and functional status in hepatocytes of immature liver.

  2. Responses of Electromyogram Activity in Adductor Longus Muscle of Rats to the Altered Gravity Levels

    NASA Astrophysics Data System (ADS)

    Ohira, Takashi; Wang, Xiao Dong; Terada, Masahiro; Kawano, Fuminori; Higo, Yoko; Nakai, Naoya; Ochiai, Toshimasa; Gyotoku, Jyunichirou; Nishimoto, Norihiro; Ogura, Akihiko; Ohira, Yoshinobu

    2008-06-01

    Responses of electromyogram (EMG) activities in the rostral and caudal regions of adductor longus (AL) muscle to altered gravity levels during parabolic flight of a jet airplane, as well as hindlimb suspension, were investigated in adult rats. Tonic EMGs in both regions were noted when the rats were exposed to hyper-G, as well as 1-G. The hip joints were adducted and the sedental quadrupedal position was maintained at these G levels. However, the EMG activities in these regions decreased and became phasic, when the hip joints were abducted and extended backward in μ-G environment. Such changes of joint angles caused passive shortening of sarcomeres only in the caudal region of AL. Atrophy and shift toward fast-twitch type were noted in fibers of the caudal region after 16-day unloading. Although fiber transformation was also induced in the rostral region, no atrophy was seen in fast-twitch fibers. The data may suggest that the atrophy and shift of phenotype caused by gravitational unloading in fibers of the caudal region may be related to the decrease in the neural and mechanical activities. Fiber type transformation toward fast-twitch type may be also related to the change of muscle activity from tonic to phasic patterns, which are the typical characteristics of fast-twitch muscle. However, the responses to unloading in fibers of rostral region were not related to the reduction of mechanical load.

  3. Neonatal exposure to amphetamine alters social affiliation and central dopamine activity in adult male prairie voles.

    PubMed

    Fukushiro, D F; Olivera, A; Liu, Y; Wang, Z

    2015-10-29

    The prairie vole (Microtus ochrogaster) is a socially monogamous rodent species that forms pair bonds after mating. Recent data have shown that amphetamine (AMPH) is rewarding to prairie voles as it induces conditioned place preferences. Further, repeated treatment with AMPH impairs social bonding in adult prairie voles through a central dopamine (DA)-dependent mechanism. The present study examined the effects of neonatal exposure to AMPH on behavior and central DA activity in adult male prairie voles. Our data show that neonatal exposure to AMPH makes voles less social in an affiliation test during adulthood, but does not affect animals' locomotor activity and anxiety-like behavior. Neonatal exposure to AMPH also increases the levels of tyrosine hydroxylase (TH) and DA transporter (DAT) mRNA expression in the ventral tegmental area (VTA) in the brain, indicating an increase in central DA activity. As DA has been implicated in AMPH effects on behavioral and cognitive functions, altered DA activity in the vole brain may contribute to the observed changes in social behavior.

  4. Structural changes in intermediate filament networks alter the activity of insulin-degrading enzyme

    PubMed Central

    Chou, Ying-Hao; Kuo, Wen-Liang; Rosner, Marsha Rich; Tang, Wei-Jen; Goldman, Robert D.

    2009-01-01

    The intermediate filament (IF) protein nestin coassembles with vimentin and promotes the disassembly of these copolymers when vimentin is hyperphosphorylated during mitosis. The aim of this study is to determine the function of these nonfilamentous particles by identifying their interacting partners. In this study, we report that these disassembled vimentin/nestin complexes interact with insulin degrading enzyme (IDE). Both vimentin and nestin interact with IDE in vitro, but vimentin binds IDE with a higher affinity than nestin. Although the interaction between vimentin and IDE is enhanced by vimentin phosphorylation at Ser-55, the interaction between nestin and IDE is phosphorylation independent. Further analyses show that phosphorylated vimentin plays the dominant role in targeting IDE to the vimentin/nestin particles in vivo, while the requirement for nestin is related to its ability to promote vimentin IF disassembly. The binding of IDE to either nestin or phosphorylated vimentin regulates IDE activity differently, depending on the substrate. The insulin degradation activity of IDE is suppressed ∼50% by either nestin or phosphorylated vimentin, while the cleavage of bradykinin-mimetic peptide by IDE is increased 2- to 3-fold. Taken together, our data demonstrate that the nestin-mediated disassembly of vimentin IFs generates a structure capable of sequestering and modulating the activity of IDE.—Chou, Y.-H., Kuo, W.-L., Rich Rosner, M., Tang, W.-J., Goldman, R. D. Structural changes in intermediate filament networks alter the activity of insulin-degrading enzyme. PMID:19584300

  5. Functional insights into modulation of BKCa channel activity to alter myometrial contractility

    PubMed Central

    Lorca, Ramón A.; Prabagaran, Monali; England, Sarah K.

    2014-01-01

    The large-conductance voltage- and Ca2+-activated K+ channel (BKCa) is an important regulator of membrane excitability in a wide variety of cells and tissues. In myometrial smooth muscle, activation of BKCa plays essential roles in buffering contractility to maintain uterine quiescence during pregnancy and in the transition to a more contractile state at the onset of labor. Multiple mechanisms of modulation have been described to alter BKCa channel activity, expression, and cellular localization. In the myometrium, BKCa is regulated by alternative splicing, protein targeting to the plasma membrane, compartmentation in membrane microdomains, and posttranslational modifications. In addition, interaction with auxiliary proteins (i.e., β1- and β2-subunits), association with G-protein coupled receptor signaling pathways, such as those activated by adrenergic and oxytocin receptors, and hormonal regulation provide further mechanisms of variable modulation of BKCa channel function in myometrial smooth muscle. Here, we provide an overview of these mechanisms of BKCa channel modulation and provide a context for them in relation to myometrial function. PMID:25132821

  6. Neonatal exposure to amphetamine alters social affiliation and central dopamine activity in adult male prairie voles.

    PubMed

    Fukushiro, D F; Olivera, A; Liu, Y; Wang, Z

    2015-10-29

    The prairie vole (Microtus ochrogaster) is a socially monogamous rodent species that forms pair bonds after mating. Recent data have shown that amphetamine (AMPH) is rewarding to prairie voles as it induces conditioned place preferences. Further, repeated treatment with AMPH impairs social bonding in adult prairie voles through a central dopamine (DA)-dependent mechanism. The present study examined the effects of neonatal exposure to AMPH on behavior and central DA activity in adult male prairie voles. Our data show that neonatal exposure to AMPH makes voles less social in an affiliation test during adulthood, but does not affect animals' locomotor activity and anxiety-like behavior. Neonatal exposure to AMPH also increases the levels of tyrosine hydroxylase (TH) and DA transporter (DAT) mRNA expression in the ventral tegmental area (VTA) in the brain, indicating an increase in central DA activity. As DA has been implicated in AMPH effects on behavioral and cognitive functions, altered DA activity in the vole brain may contribute to the observed changes in social behavior. PMID:26321240

  7. Effect alteration of methamphetamine by amino acids or their salts on ambulatory activity in mice.

    PubMed

    Kuribara, H; Tadokoro, S

    1983-02-01

    Effect alterations of methamphetamine by pretreatment of amino acids or their salts on ambulatory activity in mice were investigated to confirm a fact that certain amino acids, particularly monosodium L-glutamate, are added to methamphetamine by the street users, and that the amino acids augment the effect of methamphetamine. The ambulatory activity of mouse was measured by a tilting-type round activity cage of 25 cm in diameter. The amino acids or their salts tested were monosodium L-glutamate, monosodium L-aspartate, gamma-amino-butyric acid, L-alanine, L-lysine hydrochloride and L-arginine hydrochloride. A single administration of each chemical at doses of 1 and 2 g/kg i.p. did not induce a marked change in the ambulatory activity in mice. Methamphetamine 2 mg/kg s.c. induced an increase in the ambulatory activity with a peak at 40 min after the administration, and the increased ambulatory activity persisted for 3 hr. The ambulation-increasing effect of methamphetamine was augmented by the pretreatment of monosodium L-glutamate and monosodium L-aspartate at 30 min before the methamphetamine administration, while attenuated by the pretreatment of L-lysine hydrochloride and L-arginine hydrochloride in a dose-dependent manner. Gamma-aminobutyric acid and L-alanine did not affect the effect of methamphetamine. Similar augmentation and attenuation in the ambulation-increasing effect of methamphetamine were induced by the pretreatment of sodium bicarbonate 0.9 g/kg i.p. (urinary alkalizer) and ammonium chloride 0.07 g/kg i.p. (urinary acidifier), respectively. The urinary pH level was elevated by the administration of monosodium L-glutamate, monosodium L-aspartate and sodium bicarbonate, and decreased by L-lysine hydrochloride, L-arginine hydrochloride and ammonium chloride. Gamma-aminobutyric acid and L-alanine did not elicit a marked change in the urinary pH level. The present experiment confirms the fact in human that monosodium L-glutamate augments the effect of

  8. PRENATAL ALCOHOL EXPOSURE ALTERS STEADY-STATE AND ACTIVATED GENE EXPRESSION IN THE ADULT RAT BRAIN

    PubMed Central

    Stepien, Katarzyna A.; Lussier, Alexandre A.; Neumann, Sarah M.; Pavlidis, Paul; Kobor, Michael S.; Weinberg, Joanne

    2016-01-01

    Background Prenatal alcohol exposure (PAE) is associated with alterations in numerous physiological systems, including the stress and immune systems . We have previously shown that PAE increases the course and severity of arthritis in an adjuvant-induced arthritis (AA) model. While the molecular mechanisms underlying these effects are not fully known, changes in neural gene expression are emerging as important factors in the etiology of PAE effects. As the prefrontal cortex (PFC) and hippocampus (HPC) play key roles in neuroimmune function, PAE-induced alterations to their transcriptome may underlie abnormal steady-state functions and responses to immune challenge. The current study examined brains from adult PAE and control females from our recent AA study to determine whether PAE causes long-term alterations in gene expression and whether these mediate the altered severity and course of arthritis in PAE females Methods Adult females from PAE, pair-fed [PF], and ad libitum-fed control [C]) groups were injected with either saline or complete Freund’s adjuvant. Animals were terminated at the peak of inflammation or during resolution (days 16 and 39 post-injection, respectively); cohorts of saline-injected PAE, PF and C females were terminated in parallel. Gene expression was analyzed in the PFC and HPC using whole genome mRNA expression microarrays. Results Significant changes in gene expression in both the PFC and HPC were found in PAE compared to controls in response to ethanol exposure alone (saline-injected females), including genes involved in neurodevelopment, apoptosis, and energy metabolism. Moreover, in response to inflammation (adjuvant-injected females), PAE animals showed unique expression patterns, while failing to exhibit the activation of genes and regulators involved in the immune response observed in control and pair-fed animals. Conclusions These results support the hypothesis that PAE affects neuroimmune function at the level of gene expression

  9. Whole Blood Activation Results in Altered T Cell and Monocyte Cytokine Production Profiles by Flow Cytometry

    NASA Technical Reports Server (NTRS)

    Crucian, Brian E.; Sams, Clarence F.

    2001-01-01

    An excellent monitor of the immune balance of peripheral circulating cells is to determine their cytokine production patterns in response to stimuli. Using flow cytometry, a positive identification of cytokine producing cells in a mixed culture may be achieved. Recently, the ability to assess cytokine production following a whole-blood activation culture has been described. In this study, whole blood activation was compared to traditional PBMC activation and the individual cytokine secretion patterns for both T cells, T cell subsets and monocytes was determined by flow cytometry. RESULTS: For T cell cytokine assessment (IFNg/IL-10 and IL-21/L-4) following PMA +ionomycin activation: (1) a Significantly greater percentages of T cells producing IFNgamma and IL-2 were observed following whole-blood culture and (2) altered T cell cytokine production kinetics were observed by varying whole blood culture times. Four-color analysiS was used to allow assessment of cytokine production by specific T cell subsets. It was found that IFNgamma production was significantly elevated in the CD3+/CD8+ T cell population as compared to the CD3+/CD8- population following five hours of whole blood activation. Conversely, IL-2 and IL-10 production were Significantly elevated in the CD3+/CD8- T cell population as compared to the CD3+/CD8+ population. Monocyte cytokine production was assessed in both culture systems following LPS activation for 24 hours. A three-color flow cytometric was used to assess two cytokines (IL-1a/IL-12 and TNFa/IL-10) in conjunction with CD14. Nearly all monocytes were stimulated to produce IL-1a, IL-12 and TNFa. equally well in both culture systems, however monocyte production of IL-10 was significantly elevated in whole blood culture as compared to PBMC culture. IL-12 producing monocytes appeared to be a distinct subpopulation of the IL-1a producing set, whereas IL-10 and TNFa producing monocytes were largely mutually exclusive. IL-10 and TNFa producing

  10. NF-Y activates genes of metabolic pathways altered in cancer cells.

    PubMed

    Benatti, Paolo; Chiaramonte, Maria Luisa; Lorenzo, Mariangela; Hartley, John A; Hochhauser, Daniel; Gnesutta, Nerina; Mantovani, Roberto; Imbriano, Carol; Dolfini, Diletta

    2016-01-12

    The trimeric transcription factor NF-Y binds to the CCAAT box, an element enriched in promoters of genes overexpressed in tumors. Previous studies on the NF-Y regulome identified the general term metabolism as significantly enriched. We dissect here in detail the targeting of metabolic genes by integrating analysis of NF-Y genomic binding and profilings after inactivation of NF-Y subunits in different cell types. NF-Y controls de novo biosynthetic pathways of lipids, teaming up with the master SREBPs regulators. It activates glycolytic genes, but, surprisingly, is neutral or represses mitochondrial respiratory genes. NF-Y targets the SOCG (Serine, One Carbon, Glycine) and Glutamine pathways, as well as genes involved in the biosynthesis of polyamines and purines. Specific cancer-driving nodes are generally under NF-Y control. Altogether, these data delineate a coherent strategy to promote expression of metabolic genes fuelling anaerobic energy production and other anabolic pathways commonly altered in cancer cells.

  11. Adult Female Rats Altered Diurnal Locomotor Activity Pattern Following Chronic Methylphenidate Treatment

    PubMed Central

    Trinh, T.; Kohllepin, S; Yang, P.B.; Burau, K.D.; Dafny, N.

    2014-01-01

    Methylphenidate (MPD) is one of the most prescribed pharmacological agents and also used as cognitive enhancement and for recreational purposes. The objective of this study was to investigate the repetitive dose-response effects of MPD on rhythm locomotor activity pattern of female WKY rats and compare to prior study done on male. The hypothesis is that change in the circadian activity pattern indicates a long-lasting effect of the drug. Four animal groups (saline control, 0.6, 2.5, and 10.0 mg/kg MPD dose groups) were housed in a sound-controlled room at 12:12 light/dark cycle. All received saline injections on experimental day 1 (ED 1). On EDs 2-7, the control group received saline injection; the other groups received 0.6, 2.5, or 10.0 mg/kg MPD, respectively. On ED 8-10, injections were withheld. On ED 11, each group received the same dose as EDs 2-7. Hourly histograms and cosine statistical analyses calculating the acrophase (ϕ), amplitude (A), and MESOR (M) were applied to assess the 24-hour circadian activity pattern. The 0.6 and 2.5 mg/kg MPD groups exhibited significant (p<0.05) change in their circadian activity pattern on ED 11. The 10.0 mg/kg MPD group exhibited tolerance on ED 11 and also a significant change in activity pattern on ED 8 compared to ED 1, consistent with withdrawal behavior (p<0.007). In conclusion, chronic MPD administration alters circadian locomotor activity of adult female WKY rats and confirms that chronic MPD use elicits long lasting effects PMID:23893293

  12. Altered testicular microsomal steroidogenic enzyme activities in rats with lifetime exposure to soy isoflavones.

    PubMed

    McVey, Mark J; Cooke, Gerard M; Curran, Ivan H A

    2004-12-01

    Androgen production in the testis is carried out by the Leydig cells, which convert cholesterol into androgens. Previously, isoflavones have been shown to affect serum androgen levels and steroidogenic enzyme activities. In this study, the effects of lifelong exposure to dietary soy isoflavones on testicular microsomal steroidogenic enzyme activities were examined in the rat. F1 male rats were obtained from a multi-generational study where the parental generation was fed diets containing alcohol-washed soy protein supplemented with increasing amounts of Novasoy, a commercially available isoflavone supplement. A control group was maintained on a soy-free casein protein-based diet (AIN93G). The diets were designed to approximate human consumption levels and ranged from 0 to 1046.6 mg isoflavones/kg pelleted feed, encompassing exposures representative of North American and Asian diets as well as infant fed soy-based formula. Activities of testicular 3beta-hydroxysteroid dehydrogenase (3beta-HSD), P450c17 (CYP17), 17beta-hydroxysteroid dehydrogenase (17beta-HSD) were assayed on post natal day (PND) 28, 70, 120, 240 and 360 while 5alpha-reducatase was assayed on PND 28. At PND 28, 3beta-HSD activity was elevated by approximately 50% in rats receiving 1046.6 mg total isoflavones/kg feed compared to those on the casein only diet. A similar increase in activity was observed for CYP17 in rats receiving 235.6 mg total isoflavones/kg feed, a level representative of infant exposure through formula, compared to those receiving 0mg isoflavones from the casein diet. These results demonstrate that rats fed a mixture of dietary soy isoflavones showed significantly altered enzyme activity profiles during development at PND 28 as a result of early exposure to isoflavones at levels obtainable by humans.

  13. Dioxin exposure reduces the steroidogenic capacity of mouse antral follicles mainly at the level of HSD17B1 without altering atresia

    PubMed Central

    Karman, Bethany N.; Basavarajappa, Mallikarjuna S.; Hannon, Patrick; Flaws, Jodi A.

    2013-01-01

    2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is a potent ovarian toxicant. Previously, we demonstrated that in vitro TCDD (1 nM) exposure decreases production/secretion of the sex steroid hormones progesterone (P4), androstenedione (A4), testosterone (T), and 17β-estradiol (E2) in mouse antral follicles. The purpose of this study was to determine the mechanism by which TCDD inhibits steroidogenesis. Specifically, we examined the effects of TCDD on the steroidogenic enzymes, atresia, and the aryl hydrocarbon receptor (AHR) protein. TCDD exposure for 48 h increased levels of A4, without changing HSD3B1 protein, HSD17B1 protein, estrone (E1), T or E2 levels. Further, TCDD did not alter atresia ratings compared to vehicle at 48 h. TCDD, however, did down regulate the AHR protein at 48 h. TCDD exposure for 96 h decreased transcript levels for Cyp11a1, Cyp17a1, Hsd17b1, and Cyp19a1, but increased Hsd3b1 transcript. TCDD exposure particularly lowered both Hsd17b1 transcript and HSD17B1 protein. However, TCDD exposure did not affect levels of E1 in the media nor atresia ratings at 96 h. TCDD, however, decreased levels of the proapoptotic factor Bax. Collectively, these data suggest that TCDD exposure causes a major block in the steroidogenic enzyme conversion of A4 to T and E1 to E2 and that it regulates apoptotic pathways, favoring survival over death in antral follicles. Finally, the down-regulation of the AHR protein in TCDD exposed follicles persisted at 96 h, indicating that the activation and proteasomal degradation of this receptor likely plays a central role in the impaired steroidogenic capacity and altered apoptotic pathway of exposed antral follicles. PMID:22889882

  14. Zinc oxide nanoparticles alter hatching and larval locomotor activity in zebrafish (Danio rerio).

    PubMed

    Chen, Te-Hao; Lin, Chia-Chi; Meng, Pei-Jie

    2014-07-30

    Zinc oxide nanoparticles (ZnO NP) are extensively used in various consumer products such as sunscreens and cosmetics, with high potential of being released into aquatic environments. In this study, fertilized zebrafish (Danio rerio) eggs were exposed to various concentrations of ZnO NP suspensions (control, 0.1, 0.5, 1, 5, and 10mg/L) or their respective centrifuged supernatants (0.03, 0.01, 0.08, 0.17, 0.75, and 1.21mg/L dissolved Zn ions measured) until reaching free swimming stage. Exposure to ZnO NP suspensions and their respective centrifuged supernatants caused similar hatching delay, but did not cause larval mortality or malformation. Larval activity level, mean velocity, and maximum velocity were altered in the groups exposed to high concentrations of ZnO NP (5-10mg/L) but not in the larvae exposed to the supernatants. To evaluate possible mechanism of observed effects caused by ZnO NP, we also manipulated the antioxidant environment by co-exposure to an antioxidant compound (N-acetylcysteine, NAC) or an antioxidant molecule suppressor (buthionine sulfoximine, BSO) with 5mg/L ZnO NP. Co-exposure to NAC did not alter the effects of ZnO NP on hatchability, but co-exposure to BSO caused further hatching delay. For larval locomotor activity, co-exposure to NAC rescued the behavioral effect caused by ZnO NP, but co-exposure to BSO did not exacerbate the effect. Our data indicated that toxicity of ZnO NP cannot be solely explained by dissolved Zn ions, and oxidative stress may involve in ZnO NP toxicity. PMID:24424259

  15. Moderate differences in circulating corticosterone alter receptor-mediated regulation of 5-hydroxytryptamine neuronal activity.

    PubMed

    Judge, Sarah J; Ingram, Colin D; Gartside, Sarah E

    2004-12-01

    Circulating glucocorticoid levels vary with stress and psychiatric illness and play a potentially important role in regulating transmitter systems that regulate mood. To determine whether chronic variation in corticosterone levels within the normal diurnal range altered the control of 5-hydroxytryptamine (5-HT) neuronal activity, male rats were adrenalectomized and implanted with either a 2% or 70% corticosterone/cholesterol pellet (100 mg). Two weeks later, the regulation of 5-HT neuronal activity in the dorsal raphe nucleus was studied by in vitro electrophysiology. At this time, serum corticosterone levels approximated the low-point (2%) and mid-point (70%) of the diurnal range. The excitatory response of 5-HT neurones to the alpha1-adrenoceptor agonist phenylephrine (1-11 microM) was significantly greater in the 2% group compared to the 70% group. By contrast, the inhibitory response to 5-HT (10-50 microM) was significantly lower in the 2% group compared to the 70% group. Thus, chronic variation in circulating corticosterone over a narrow part of the normal diurnal range causes a shift in the balance of positive and negative regulation of 5-HT neurones, with increased alpha 1-adrenoceptor-mediated excitation and reduced 5-HT-mediated autoinhibition at lower corticosterone levels. This shift would have a major impact on control of 5-HT neuronal activity. PMID:15582914

  16. Interleukin-15 Modulates Adipose Tissue by Altering Mitochondrial Mass and Activity

    PubMed Central

    Barra, Nicole G.; Palanivel, Rengasamy; Denou, Emmanuel; Chew, Marianne V.; Gillgrass, Amy; Walker, Tina D.; Kong, Josh; Richards, Carl D.; Jordana, Manel; Collins, Stephen M.; Trigatti, Bernardo L.; Holloway, Alison C.; Raha, Sandeep; Steinberg, Gregory R.; Ashkar, Ali A.

    2014-01-01

    Interleukin-15 (IL-15) is an immunomodulatory cytokine that affects body mass regulation independent of lymphocytes; however, the underlying mechanism(s) involved remains unknown. In an effort to investigate these mechanisms, we performed metabolic cage studies, assessed intestinal bacterial diversity and macronutrient absorption, and examined adipose mitochondrial activity in cultured adipocytes and in lean IL-15 transgenic (IL-15tg), overweight IL-15 deficient (IL-15−/−), and control C57Bl/6 (B6) mice. Here we show that differences in body weight are not the result of differential activity level, food intake, or respiratory exchange ratio. Although intestinal microbiota differences between obese and lean individuals are known to impact macronutrient absorption, differing gut bacteria profiles in these murine strains does not translate to differences in body weight in colonized germ free animals and macronutrient absorption. Due to its contribution to body weight variation, we examined mitochondrial factors and found that IL-15 treatment in cultured adipocytes resulted in increased mitochondrial membrane potential and decreased lipid deposition. Lastly, IL-15tg mice have significantly elevated mitochondrial activity and mass in adipose tissue compared to B6 and IL-15−/− mice. Altogether, these results suggest that IL-15 is involved in adipose tissue regulation and linked to altered mitochondrial function. PMID:25517731

  17. Bilateral Limb Phase Relationship and Its Potential to Alter Muscle Activity Phasing During Locomotion

    PubMed Central

    López-Ortiz, Citlali; Walter, Charles B.; Brown, David A.

    2009-01-01

    It is well established that the sensorimotor state of one limb can influence another limb and therefore bilateral somatosensory inputs make an important contribution to interlimb coordination patterns. However, the relative contribution of interlimb pathways for modifying muscle activation patterns in terms of phasing is less clear. Here we studied adaptation of muscle activity phasing to the relative angular positions of limbs using a split-crank ergometer, where the cranks could be decoupled to allow different spatial angular position relationships. Twenty neurologically healthy individuals performed the specified pedaling tasks at different relative angular positions while surface electromyographic (EMG) signals were recorded bilaterally from eight lower extremity muscles. During each experiment, the relative angular crank positions were altered by increasing or decreasing their difference by randomly ordered increments of 30° over the complete cycle [0° (in phase pedaling); 30, 60, 90, 120, 150, and 180° (standard pedaling); and 210, 240, 270, 300, and 330° out of phase pedaling]. We found that manipulating the relative angular positions of limbs in a pedaling task caused muscle activity phasing changes that were either delayed or advanced, dependent on the relative spatial position of the two cranks and this relationship is well-explained by a sine curve. Further, we observed that the magnitude of phasing changes in biarticular muscles (like rectus femoris) was significantly greater than those of uniarticular muscles (like vastus medialis). These results are important because they provide new evidence that muscle phasing can be systematically influenced by interlimb pathways. PMID:19741107

  18. An 8-Month Randomized Controlled Exercise Trial Alters Brain Activation During Cognitive Tasks in Overweight Children

    PubMed Central

    Krafft, Cynthia E.; Schwarz, Nicolette F.; Chi, Lingxi; Weinberger, Abby L.; Schaeffer, David J.; Pierce, Jordan E.; Rodrigue, Amanda L.; Yanasak, Nathan E.; Miller, Patricia H.; Tomporowski, Phillip D.; Davis, Catherine L.; McDowell, Jennifer E.

    2014-01-01

    Objective Children who are less fit reportedly have lower performance on tests of cognitive control and differences in brain function. This study examined the effect of an exercise intervention on brain function during two cognitive control tasks in overweight children. Design and Methods Participants included 43 unfit, overweight (BMI ≥ 85th percentile) children 8- to 11-years old (91% Black), who were randomly divided into either an aerobic exercise (n = 24) or attention control group (n = 19). Each group was offered a separate instructor-led after-school program every school day for 8 months. Before and after the program, all children performed two cognitive control tasks during functional magnetic resonance imaging (fMRI): antisaccade and flanker. Results Compared to the control group, the exercise group decreased activation in several regions supporting antisaccade performance, including precentral gyrus and posterior parietal cortex, and increased activation in several regions supporting flanker performance, including anterior cingulate and superior frontal gyrus. Conclusions Exercise may differentially impact these two task conditions, or the paradigms in which cognitive control tasks were presented may be sensitive to distinct types of brain activation that show different effects of exercise. In sum, exercise appears to alter efficiency or flexible modulation of neural circuitry supporting cognitive control in overweight children. PMID:23788510

  19. Diminished leptin signaling can alter circadian rhythm of metabolic activity and feeding.

    PubMed

    Hsuchou, Hung; Wang, Yuping; Cornelissen-Guillaume, Germaine G; Kastin, Abba J; Jang, Eunjin; Halberg, Franz; Pan, Weihong

    2013-10-01

    Leptin, a hormone mainly produced by fat cells, shows cell-specific effects to regulate feeding and metabolic activities. We propose that an important feature of metabolic dysregulation resulting in obesity is the loss of the circadian rhythm of biopotentials. This was tested in the pan-leptin receptor knockout (POKO) mice newly generated in our laboratory. In the POKO mice, leptin no longer induced pSTAT-3 signaling after intracerebroventricular injection. Three basic phenotypes were observed: the heterozygotes had similar weight and adiposity as the wild-type (WT) mice (>60% of the mice); the homozygotes were either fatter (∼30%), or rarely leaner (<5%) than the WT mice. By early adulthood, the POKO mice had higher average body weight and adiposity than their respective same-sex WT littermate controls, and this was consistent among different batches. The homozygote fat POKO showed significant reduction of midline estimating statistic of rhythm of circadian parameters, and shifts of ultradian rhythms. The blunted circadian rhythm of these extremely obese POKO mice was also seen in their physical inactivity, longer feeding bouts, and higher food intake. The extent of obesity correlated with the blunted circadian amplitude, accumulative metabolic and locomotor activities, and the severity of hyperphagia. This contrasts with the heterozygote POKO mice which showed little obesity and metabolic disturbance, and only subtle changes of the circadian rhythm of metabolic activity without alterations in feeding behavior. The results provide a novel aspect of leptin resistance, almost manifesting as an "all or none" phenomenon.

  20. Altered Intrinsic Regional Activity and Interregional Functional Connectivity in Post-stroke Aphasia

    PubMed Central

    Yang, Mi; Li, Jiao; Li, Yibo; Li, Rong; Pang, Yajing; Yao, Dezhong; Liao, Wei; Chen, Huafu

    2016-01-01

    Several neuroimaging studies have examined cerebral function in patients who suffer from aphasia, but the mechanism underlying this disorder remains poorly understood. In this study, we examined alterations in the local regional and remote interregional network cerebral functions in aphasia combined with amplitude of low-frequency fluctuations and interregional functional connectivity (FC) using resting-state functional magnetic resonance imaging. A total of 17 post-stroke aphasic patients, all having suffered a stroke in the left hemisphere, as well as 20 age- and sex-matched healthy controls, were enrolled in this study. The aphasic patients showed significantly increased intrinsic regional activity mainly in the contralesional mesial temporal (hippocampus/parahippocampus, [HIP/ParaHIP]) and lateral temporal cortices. In addition, intrinsic regional activity in the contralesional HIP/ParaHIP was negatively correlated with construction score. Aphasic patients showed increased remote interregional FC between the contralesional HIP/ParaHIP and fusiform gyrus, but reduced FC in the ipsilesional occipital and parietal cortices. These findings suggested that the intrinsic regional brain dysfunctions in aphasia were related to interregional functional connectivity. Changes in the intrinsic regional brain activity and associated remote functional connectivity pattern would provide valuable information to enhance the understanding of the pathophysiological mechanisms of aphasia. PMID:27091494

  1. Exogenous Alpha-Synuclein Alters Pre- and Post-Synaptic Activity by Fragmenting Lipid Rafts.

    PubMed

    Emanuele, Marco; Esposito, Alessandro; Camerini, Serena; Antonucci, Flavia; Ferrara, Silvia; Seghezza, Silvia; Catelani, Tiziano; Crescenzi, Marco; Marotta, Roberto; Canale, Claudio; Matteoli, Michela; Menna, Elisabetta; Chieregatti, Evelina

    2016-05-01

    Alpha-synuclein (αSyn) interferes with multiple steps of synaptic activity at pre-and post-synaptic terminals, however the mechanism/s by which αSyn alters neurotransmitter release and synaptic potentiation is unclear. By atomic force microscopy we show that human αSyn, when incubated with reconstituted membrane bilayer, induces lipid rafts' fragmentation. As a consequence, ion channels and receptors are displaced from lipid rafts with consequent changes in their activity. The enhanced calcium entry leads to acute mobilization of synaptic vesicles, and exhaustion of neurotransmission at later stages. At the post-synaptic terminal, an acute increase in glutamatergic transmission, with increased density of PSD-95 puncta, is followed by disruption of the interaction between N-methyl-d-aspartate receptor (NMDAR) and PSD-95 with ensuing decrease of long term potentiation. While cholesterol loading prevents the acute effect of αSyn at the presynapse; inhibition of casein kinase 2, which appears activated by reduction of cholesterol, restores the correct localization and clustering of NMDARs.

  2. Alterations in activation and deactivation of mutagens in aging rat liver.

    PubMed

    Masuda, M; Nukuzuma, C; Kazusaka, A; Fujita, S

    1995-09-01

    Age-associated alternations in activation and deactivation of benzo[a]pyrene (BP), furylfuramide (AF2), and 2-nitrofluorene (NF) in rat liver were investigated. A modified Ames mutagenicity test system used liver 9000 g supernatant (S-9) from male Fischer 344 rats aged 3, 6, 12, and 24 months fortified with NADPH generating system alone or together with cofactors of conjugating enzymes. The numbers of revertant colonies due to mutagenic activation of BP during preincubation were markedly high in young rats and decreased with aging. They were decreased by the addition of UDP-glucuronic acid (15 mM) or glutathione (30 mM), the cofactors of UDP-glucuronyl transferase and glutathione S-transferase, respectively, in the preincubation mixture. The difference in the BP activation by liver S-9 from different age groups almost disappeared by the addition of reduced glutathione. A direct mutagen, AF2, was not metabolized during preincubation in the absence of cofactors of conjugating enzymes, but detoxified up to about 50% by the addition of glutathione to the preincubation mixture containing liver S-9 from rats of any age group. Another direct mutagen, NF, was partly detoxified during preincubation by liver S-9 from 3-month-old rats more than by that from 24-month-old rats. It is suggested that incidence of chemical carcinogenesis may increase along with aging due to the altered xenobiotics metabolism. PMID:7671022

  3. Spaceflight alters expression of microRNA during T-cell activation.

    PubMed

    Hughes-Fulford, Millie; Chang, Tammy T; Martinez, Emily M; Li, Chai-Fei

    2015-12-01

    Altered immune function has been demonstrated in astronauts during spaceflights dating back to Apollo and Skylab; this could be a major barrier to long-term space exploration. We tested the hypothesis that spaceflight causes changes in microRNA (miRNA) expression. Human leukocytes were stimulated with mitogens on board the International Space Station using an onboard normal gravity control. Bioinformatics showed that miR-21 was significantly up-regulated 2-fold during early T-cell activation in normal gravity, and gene expression was suppressed under microgravity. This was confirmed using quantitative real-time PCR (n = 4). This is the first report that spaceflight regulates miRNA expression. Global microarray analysis showed significant (P < 0.05) suppression of 85 genes under microgravity conditions compared to normal gravity samples. EGR3, FASLG, BTG2, SPRY2, and TAGAP are biologically confirmed targets and are co-up-regulated with miR-21. These genes share common promoter regions with pre-mir-21; as the miR-21 matures and accumulates, it most likely will inhibit translation of its target genes and limit the immune response. These data suggest that gravity regulates T-cell activation not only by transcription promotion but also by blocking translation via noncoding RNA mechanisms. Moreover, this study suggests that T-cell activation itself may induce a sequence of gene expressions that is self-limited by miR-21. PMID:26276131

  4. Spaceflight alters expression of microRNA during T-cell activation.

    PubMed

    Hughes-Fulford, Millie; Chang, Tammy T; Martinez, Emily M; Li, Chai-Fei

    2015-12-01

    Altered immune function has been demonstrated in astronauts during spaceflights dating back to Apollo and Skylab; this could be a major barrier to long-term space exploration. We tested the hypothesis that spaceflight causes changes in microRNA (miRNA) expression. Human leukocytes were stimulated with mitogens on board the International Space Station using an onboard normal gravity control. Bioinformatics showed that miR-21 was significantly up-regulated 2-fold during early T-cell activation in normal gravity, and gene expression was suppressed under microgravity. This was confirmed using quantitative real-time PCR (n = 4). This is the first report that spaceflight regulates miRNA expression. Global microarray analysis showed significant (P < 0.05) suppression of 85 genes under microgravity conditions compared to normal gravity samples. EGR3, FASLG, BTG2, SPRY2, and TAGAP are biologically confirmed targets and are co-up-regulated with miR-21. These genes share common promoter regions with pre-mir-21; as the miR-21 matures and accumulates, it most likely will inhibit translation of its target genes and limit the immune response. These data suggest that gravity regulates T-cell activation not only by transcription promotion but also by blocking translation via noncoding RNA mechanisms. Moreover, this study suggests that T-cell activation itself may induce a sequence of gene expressions that is self-limited by miR-21.

  5. Field Trip Guide to Serpentinite, Silica-Carbonate Alteration, and Related Hydrothermal Activity in the Clear Lake Region, California

    SciTech Connect

    Fraser Goff; George Guthrie

    1999-06-01

    This guide is designed to familiarize scientists with the geology, structure, alteration, and fluids typical of California serpentinites for purposes of carbon dioxide sequestration (Lackner et al., 1995). Goff et al. (1997) and Goff and Lackner (1998) describe the geology and geochemistry of some of the serpentinites from this area. Mechanisms of silica-carbonate alteration were outlined by Barnes et al. (1973). Donnelly-Nolan et al. (1993) most recently reviewed relations between regional hydrothermal alteration and Quarternary volcanic activity. Stanley et al. (1998) summarized geophysical characteristics of the region.

  6. Scapular Bracing and Alteration of Posture and Muscle Activity in Overhead Athletes With Poor Posture

    PubMed Central

    Cole, Ashley K; McGrath, Melanie L; Harrington, Shana E; Padua, Darin A; Rucinski, Terri J; Prentice, William E

    2013-01-01

    Context Overhead athletes commonly have poor posture. Commercial braces are used to improve posture and function, but few researchers have examined the effects of shoulder or scapular bracing on posture and scapular muscle activity. Objective To examine whether a scapular stabilization brace acutely alters posture and scapular muscle activity in healthy overhead athletes with forward-head, rounded-shoulder posture (FHRSP). Design Randomized controlled clinical trial. Setting Applied biomechanics laboratory. Patients or Other Participants Thirty-eight healthy overhead athletes with FHRSP. Intervention(s) Participants were assigned randomly to 2 groups: compression shirt with no strap tension (S) and compression shirt with the straps fully tensioned (S + T). Posture was measured using lateral-view photography with retroreflective markers. Electromyography (EMG) of the upper trapezius (UT), middle trapezius (MT), lower trapezius (LT), and serratus anterior (SA) in the dominant upper extremity was measured during 4 exercises (scapular punches, W's, Y's, T's) and 2 glenohumeral motions (forward flexion, shoulder extension). Posture and exercise EMG measurements were taken with and without the brace applied. Main Outcome Measure(s) Head and shoulder angles were measured from lateral-view digital photographs. Normalized surface EMG was used to assess mean muscle activation of the UT, MT, LT, and SA. Results Application of the brace decreased forward shoulder angle in the S + T condition. Brace application also caused a small increase in LT EMG during forward flexion and Y's and a small decrease in UT and MT EMG during shoulder extension. Brace application in the S + T group decreased UT EMG during W's, whereas UT EMG increased during W's in the S group. Conclusions Application of the scapular brace improved shoulder posture and scapular muscle activity, but EMG changes were highly variable. Use of a scapular brace might improve shoulder posture and muscle activity in

  7. Characterization of Bacillus licheniformis 6346 Mutants Which Have Altered Lytic Enzyme Activities

    PubMed Central

    Forsberg, C. W.; Rogers, H. J.

    1974-01-01

    Two groups of mutants altered in lytic enzyme activities have been isolated from Bacillus licheniformis 6346 MH-1 by screening clones for halo production in agar plates containing cell wall conjugated with Procion brilliant red. In the first group which produced halos during colony formation, two were shown to contain three- and eightfold more muramyl-l-alanine amidase than the parent. These strains liberated amidase and intracellular α-glucosidase into the culture medium during exponential growth in liquid medium. Isolated walls had a normal qualitative composition and in autolysing liberated N-terminal amino acids and reducing groups. Wall preparations from the second group of mutants which did not produce halos lysed very poorly at pH 9.5, the optimal pH for amidase activity, and poorly at pH 5.5 even though they had similar endo-N-acetylglucosaminidase activities to the parent. Two of these strains that were also deficient in phosphoglucomutase had only 3 to 5% of the membrane-bound amidase activity compared with that in the parent. Cell walls of the phosphoglucomutase-deficient mutants treated with sodium dodecyl sulfate to inactivate endogenous lytic enzymes were dissolved at 10% of the rate of those from the parent by added amidase, but their sensitivities to lysozyme were similar. Those from one mutant had 10 to 20% of the amidase-binding capacity of parent walls, whereas its isolated mucopeptide was essentially inactive in this respect. The failure of these phosphoglucomutase-deficient mutants to autolyse is likely to be due to the combined effects of both low amidase activity and resistant walls. As a result, daughter cells are unable to separate and long chains are formed during exponential growth. PMID:4828303

  8. Regulation and activity of secretory leukoprotease inhibitor (SLPI) is altered in smokers

    PubMed Central

    Meyer, Megan; Bauer, Rebecca N.; Letang, Blanche D.; Brighton, Luisa; Thompson, Elizabeth; Simmen, Rosalia C. M.; Bonner, James

    2013-01-01

    A hallmark of cigarette smoking is a shift in the protease/antiprotease balance, in favor of protease activity. However, it has recently been shown that smokers have increased expression of a key antiprotease, secretory leukoprotease inhibitor (SLPI), yet the mechanisms involved in SLPI transcriptional regulation and functional activity of SLPI remain unclear. We examined SLPI mRNA and protein secretion in differentiated nasal epithelial cells (NECs) and nasal lavage fluid (NLF) from nonsmokers and smokers and demonstrated that SLPI expression is increased in NECs and NLF from smokers. Transcriptional regulation of SLPI expression was confirmed using SLPI promoter reporter assays followed by chromatin immunoprecipitation. The role of STAT1 in regulating SLPI expression was further elucidated using WT and stat1−/− mice. Our data demonstrate that STAT1 regulates SLPI transcription in epithelial cells and slpi protein in the lungs of mice. Additionally, we reveal that NECs from smokers have increased STAT1 mRNA/protein expression. Finally, we demonstrate that SLPI contained in the nasal mucosa of smokers is proteolytically cleaved but retains functional activity against neutrophil elastase. These results demonstrate that smoking enhances expression of SLPI in NECs in vitro and in vivo, and that this response is regulated by STAT1. In addition, despite posttranslational cleavage of SLPI, antiprotease activity against neutrophil elastase is enhanced in smokers. Together, our findings show that SLPI regulation and activity is altered in the nasal mucosa of smokers, which could have broad implications in the context of respiratory inflammation and infection. PMID:24285265

  9. Reproductive experience alters neural and behavioural responses to acute oestrogen receptor α activation.

    PubMed

    Byrnes, E M; Casey, K; Carini, L M; Bridges, R S

    2013-12-01

    demonstrate that reproductive experience alters the behavioural response to acute ERα activation. Moreover, the findings suggest that central regulation of the hypothalamic-adrenal-pituitary axis is modified as a consequence of reproductive experience.

  10. Activation of 5-HT3 receptors leads to altered responses 6 months after MDMA treatment.

    PubMed

    Gyongyosi, Norbert; Balogh, Brigitta; Katai, Zita; Molnar, Eszter; Laufer, Rudolf; Tekes, Kornelia; Bagdy, Gyorgy

    2010-03-01

    The recreational drug "Ecstasy" [3,4-methylenedioxymethamphetamine (MDMA)] has a well-characterised neurotoxic effect on the 5-hydroxytryptamine (5-HT) neurons in animals. Despite intensive studies, the long-term functional consequencies of the 5-HT neurodegeneration remains elusive. The aim of this study was to investigate whether any alteration of 5-hydroxytryptamine-3 (5-HT(3)) receptor functions on the sleep-wake cycle, motor activity, and quantitative EEG could be detected 6 months after a single dose of 15 mg/kg of MDMA. The selective 5-HT(3) receptor agonist m-chlorophenylbiguanide (mCPBG; 1 mg/kg, i.p.) or vehicle was administered to freely moving rats pre-treated with MDMA (15 mg/kg, i.p.) or vehicle 6 months earlier. Polysomnographic and motor activity recordings were performed. Active wake (AW), passive wake (PW), light slow wave sleep (SWS-1), deep slow wave sleep (SWS-2), and paradoxical sleep were classified. In addition, EEG power spectra were calculated for the second hour after mCPBG treatment for each stage. AW increased and SWS-1 decreased in the second hour after mCPBG treatment in control animals. mCPBG caused significant changes in the EEG power in states with cortical activation (AW, PW, paradoxical sleep). In addition, mCPBG had a biphasic effect on hippocampal theta power in AW with a decrease in 7 Hz and a stage-selective increase in the upper range (8-9 Hz). Effects of mCPBG on the time spent in AW and SWS-1 were eliminated or reduced in MDMA-treated animals. In addition, mCPBG did not increase the upper theta power of AW in rats pre-treated with MDMA. These data suggest long-term changes in 5-HT(3) receptor function after MDMA. PMID:20052506

  11. Altered polymorphonuclear leukocyte Fc gamma R expression contributes to decreased candicidal activity during intraabdominal sepsis

    SciTech Connect

    Simms, H.H.; D'Amico, R.; Monfils, P.; Burchard, K.W. )

    1991-03-01

    We investigated the effects of untreated intraabdominal sepsis on polymorphonuclear leukocyte (PMN) candicidal activity. Two groups of swine were studied. Group I (n=6) underwent sham laparotomy, group II (n=7) underwent cecal ligation and incision. Untreated intraabdominal sepsis resulted in a progressive decrease in PMN candicidal activity. Concomitant rosetting and phagocytosis assays demonstrated a decrease in both the attachment and phagocytosis of Candida albicans opsonized with both normal and septic swine serum by PMNs in group II. Iodine 125-labeled swine immunoglobulin G (IgG) and fluorescein isothioalanate (FITC)-labeled swine IgG were used to investigate Fc gamma receptor ligand interactions. Scatchard analyses demonstrated a progressive decline in both the binding affinity constant and number of IgG molecules bound per PMN. Stimulation of the oxidative burst markedly reduced 125I-labeled IgG binding in both group I and group II, with a greater decrement being seen in animals with intraabdominal sepsis. Further, in group II, PMN recycling of the Fc gamma receptor to the cell surface after generation of the oxidative burst was reduced by postoperative day 4. Binding of monoclonal antibodies to Fc gamma receptor II, but not Fc gamma receptor I/III markedly reduced intracellular candicidal activity. Immunofluorescence studies revealed a homogeneous pattern of FITC-IgG uptake by nearly all group I PMNs, whereas by postoperative day 8 a substantial number of PMNs from group II failed to internalize the FITC-IgG. These studies suggest that untreated intraabdominal sepsis reduces PMN candicidal activity and that this is due, in part, to altered PMN Fc gamma receptor ligand interactions.

  12. Altered relationships between age and functional brain activation in adolescents at clinical high risk for psychosis

    PubMed Central

    Karlsgodt, Katherine H.; van Erp, Theo G.M.; Bearden, Carrie E.; Cannon, Tyrone D.

    2014-01-01

    Schizophrenia is considered a neurodevelopmental disorder, but whether the adolescent period, proximal to onset, is associated with aberrant development in individuals at clinical high risk (CHR) for psychosis is incompletely understood. While abnormal gray and white matter development has been observed, alterations in functional neuroimaging (fMRI) parameters during adolescence as related to conversion to psychosis have not yet been investigated. Twenty CHR individuals and 19 typically developing controls (TDC), (ages 14-21), were recruited from the Center for Assessment and Prevention of Prodromal States (CAPPS) at UCLA. Participants performed a Sternberg-style verbal working memory (WMem) task during fMRI and data were analyzed using a cross-sectional design to test the hypothesis that there is a deviant developmental trajectory in WMem associated neural circuitry in those at risk for psychosis. Eight of the CHR adolescents converted to psychosis within 2 years of initial assessment. A voxel-wise regression examining the relationship between age and activation revealed a significant group-by-age interaction. TDC showed a negative association between age and functional activation in the WMem circuitry while CHR adolescents showed a positive association. Moreover, CHR patients who later converted to overt psychosis showed a distinct pattern of abnormal age-associated activation in the frontal cortex relative to controls, while non-converters showed a more diffuse posterior pattern. Finding that age related variation in baseline patterns of neural activity differentiate individuals who subsequently convert to psychosis from healthy subjects suggests that these differences are likely to be clinically relevant. PMID:24144510

  13. Altered relationships between age and functional brain activation in adolescents at clinical high risk for psychosis.

    PubMed

    Karlsgodt, Katherine H; van Erp, Theo G M; Bearden, Carrie E; Cannon, Tyrone D

    2014-01-30

    Schizophrenia is considered a neurodevelopmental disorder, but whether the adolescent period, proximal to onset, is associated with aberrant development in individuals at clinical high risk (CHR) for psychosis is incompletely understood. While abnormal gray and white matter development has been observed, alterations in functional neuroimaging (fMRI) parameters during adolescence as related to conversion to psychosis have not yet been investigated. Twenty CHR individuals and 19 typically developing controls (TDC), (ages 14-21), were recruited from the Center for Assessment and Prevention of Prodromal States (CAPPS) at UCLA. Participants performed a Sternberg-style verbal working memory (WMem) task during fMRI and data were analyzed using a cross-sectional design to test the hypothesis that there is a deviant developmental trajectory in WMem associated neural circuitry in those at risk for psychosis. Eight of the CHR adolescents converted to psychosis within 2 years of initial assessment. A voxel-wise regression examining the relationship between age and activation revealed a significant group-by-age interaction. TDC showed a negative association between age and functional activation in the WMem circuitry while CHR adolescents showed a positive association. Moreover, CHR patients who later converted to overt psychosis showed a distinct pattern of abnormal age-associated activation in the frontal cortex relative to controls, while non-converters showed a more diffuse posterior pattern. Finding that age related variation in baseline patterns of neural activity differentiate individuals who subsequently convert to psychosis from healthy subjects suggests that these differences are likely to be clinically relevant. PMID:24144510

  14. Altered protoxin activation by midgut enzymes from a Bacillus thuringiensis resistant strain of Plodia interpunctella.

    PubMed

    Oppert, B; Kramer, K J; Johnson, D E; MacIntosh, S C; McGaughey, W H

    1994-02-15

    Processing of Bacillus thuringiensis protoxins to toxins by midgut proteinases from a strain of the Indianmeal moth, Plodia interpunctella (Hubner), resistant to B. thuringiensis subspecies entomocidus (HD-198) was slower than that by midgut proteinases from the susceptible parent strain or a strain resistant to B. thuringiensis subspecies kurstaki (HD-1, Dipel). Midgut extracts from entomocidus-resistant insects exhibited five-fold lower activity toward the synthetic substrate alpha-N-benzoyl-DL-arginine rho-nitroanilide than extracts from susceptible or kurstaki-resistant insects. Midgut enzymes from susceptible or kurstaki-resistant insects converted the 133 kDa CryIA(c) protoxin to 61-63 kDa proteins, while incubations with entomocidus-resistant enzymes resulted in predominantly products of intermediate size, even with increased amounts of midgut extract. The 61-63 kDa proteins were only produced by entomocidus-resistant midgut extracts after long term incubations with the protoxin. The data suggest that altered protoxin activation by midgut proteinases is involved in some types of insect resistance to B. thuringiensis.

  15. Caffeine does not alter RPE or pain perception during intense exercise in active women.

    PubMed

    Astorino, Todd A; Roupoli, Lindsay R; Valdivieso, Britten R

    2012-10-01

    Attenuated perceptions of exertion and leg pain are typically reported during exercise with caffeine ingestion, yet these responses are relatively unexplored in women. The primary aim of this study was to assess the effect of caffeine on rating of perceived exertion (RPE) and pain perception during a simulated time trial. Ten active women (age=22.1±1.9yr) completed an 8.2km "all out" time trial on each of 3days separated by at least 48h. Initially, a practice trial was completed, and participants refrained from products containing caffeine and lower-body exercise for 24h prior to subsequent trials. During exercise, heart rate (HR), RPE, and leg pain were recorded. Using a double-blind, randomized crossover design, participants ingested anhydrous caffeine and glucose (each 6mg/kg bw+each 6mg/kg bw glucose) or placebo (each 6mg/kg bw of glucose) 1h pre-exercise. Despite not altering (P>0.05) RPE, HR, or leg pain, caffeine improved (P<0.05) cycling performance (17.7±1.0min versus 18.2±1.1min) and power output (121.6±17.5W versus 114.9±17.9W) versus placebo. Caffeine's ergogenic effects may be independent of changes in RPE or leg pain in active women performing a simulated time trial.

  16. Contractile activity of lymphatic vessels is altered in the TNBS model of guinea pig ileitis.

    PubMed

    Wu, Theresa F; Carati, Colin J; Macnaughton, Wallace K; von der Weid, Pierre-Yves

    2006-10-01

    The ability of the lymphatic system to actively remove fluid from the interstitium is critical to the resolution of edema. The response of the lymphatics to inflammatory situations is poorly studied, so we examined mesenteric lymphatic contractile activity in the 2,4,6-trinitrobenzenesulfonic acid (TNBS) model of guinea pig ileitis, a well-accepted animal model of intestinal inflammation, by videomicroscopy in vivo and in vitro 1, 3, and 6 days after induction of ileitis. Lymphatic function (diameter, constriction frequency, amplitude of constrictions, and calculated stroke volume and lymph flow rate) of isolated vessels from TNBS-treated guinea pigs were impaired compared with sham-treated controls. The dysfunction was well correlated with the degree of inflammation, with differences reaching significance (P < 0.05) at the highest inflammation-induced damage observed at day 3. In vivo, significantly fewer lymphatics exhibited spontaneous constrictions in TNBS-treated than sham-treated animals. Cyclooxygenase (COX) metabolites were suggested to be involved in this lymphatic dysfunction, since application of nonselective COX inhibitor (10 microM indomethacin) or a combination of COX-1 and COX-2 inhibitors (1 microM SC-560 and 10 microM celecoxib) markedly increased constriction frequency or induced them in lymphatics from TNBS-treated animals in vivo and in vitro. The present results demonstrate that lymphatic contractile function is altered in TNBS-induced ileitis and suggest a role for prostanoids in the lymphatic dysfunction.

  17. Alterations in locomotor activity induced by radioprotective doses of 16,16-dimethyl prostaglandin E2

    SciTech Connect

    Landauer, M.R.; Walden, T.L.; Davis, H.D.; Dominitz, J.A.

    1987-01-01

    16,16-Dimethyl prostaglandin E2 (DiPGE2) is an effective radioprotectant when administered before irradiation. A notable side effect of this compound is sedation. In separate experiments, the dose-response determinations of the time course of locomotor activity and 30-day survival after 10 Gy gamma irradiation (LD100) were made. Adult male CD2F1 mice were injected subcutaneously with vehicle or DiPGE2 in doses ranging from 0.01 to 40 micrograms per mouse. A dose of 0.01 micrograms did not result in alterations in locomotor behaviour or enhance survival. Doses greater than 1 microgram produced ataxia and enhanced radiation survival in a dose-dependent fashion. Full recovery of locomotor activity did not occur until 6 and 30 hr after injection for the 10 microgram and 40 microgram groups, respectively. Radioprotection was observed when DiPGE2 was administered preirradiation but not postirradiation. Doses of 1 and 10 micrograms were maximally effective as a radioprotectant if injected 5 min prior to irradiation (80%-90% survival). A dose of 40 micrograms resulted in 100% survival when injected 5-30 min before irradiation. Therefore, increasing doses of DiPGE2 resulted in an enhanced effectiveness as a radioprotectant. However, the doses that were the most radioprotective were also the most debilitating to the animal.

  18. Enhanced carotid body chemosensory activity and the cardiovascular alterations induced by intermittent hypoxia

    PubMed Central

    Iturriaga, Rodrigo; Andrade, David C.; Del Rio, Rodrigo

    2014-01-01

    The carotid body (CB) plays a main role in the maintenance of the oxygen homeostasis. The hypoxic stimulation of the CB increases the chemosensory discharge, which in turn elicits reflex sympathetic, cardiovascular, and ventilatory adjustments. An exacerbate carotid chemosensory activity has been associated with human sympathetic-mediated diseases such as hypertension, insulin resistance, heart failure, and obstructive sleep apnea (OSA). Indeed, the CB chemosensory discharge becomes tonically hypereactive in experimental models of OSA and heart failure. Chronic intermittent hypoxia (CIH), a main feature of OSA, enhances CB chemosensory baseline discharges in normoxia and in response to hypoxia, inducing sympathetic overactivity and hypertension. Oxidative stress, increased levels of ET-1, Angiotensin II and pro-inflammatory cytokines, along with a reduced production of NO in the CB, have been associated with the enhanced carotid chemosensory activity. In this review, we will discuss new evidence supporting a main role for the CB chemoreceptor in the autonomic and cardiorespiratory alterations induced by intermittent hypoxia, as well as the molecular mechanisms involved in the CB chemosensory potentiation. PMID:25520668

  19. Altering the interfacial activation mechanism of a lipase by solid-phase selective chemical modification.

    PubMed

    López-Gallego, Fernando; Abian, Olga; Guisán, Jose Manuel

    2012-09-01

    This study presents a combined protein immobilization, directed mutagenesis, and site-selective chemical modification approach, which was used to create a hyperactivated semisynthetic variant of BTL2. Various alkane chains were tethered at three different positions in order to mimic the lipase interfacial activation exogenously triggered by detergents. Optimum results were obtained when a dodecane chain was introduced at position 320 by solid-phase site-selective chemical modification. The resulting semisynthetic variant showed a 2.5-fold higher activity than the wild-type nonmodified variant in aqueous conditions. Remarkably, this is the maximum hyperactivation ever observed for BTL2 in the presence of detergents such as Triton X-100. We present evidence to suggest that the endogenous dodecane chain hyperactivates the enzyme in a similar fashion as an exogenous detergent molecule. In this way, we also observe a faster irreversible enzyme inhibition and an altered detergent sensitivity profile promoted by the site-selective chemical modification. These findings are also supported by fluorescence studies, which reveal that the structural conformation changes of the semisynthetic variant are different to those of the wild type, an effect that is more pronounced in the presence of detergent. Finally, the optimal immobilized semisynthetic variant was successfully applied to the selective synthesis of oxiran-2-yl butyrate. Significantly, this biocatalyst is 12-fold more efficient than the immobilized wild-type enzyme, producing the S-enantiomer with higher enantiospecificity (ee = 92%). PMID:22876885

  20. Consequences of age on ischemic wound healing in rats: altered antioxidant activity and delayed wound closure.

    PubMed

    Moor, Andrea N; Tummel, Evan; Prather, Jamie L; Jung, Michelle; Lopez, Jonathan J; Connors, Sarah; Gould, Lisa J

    2014-04-01

    Advertisements targeted at the elderly population suggest that antioxidant therapy will reduce free radicals and promote wound healing, yet few scientific studies substantiate these claims. To better understand the potential utility of supplemental antioxidant therapy for wound healing, we tested the hypothesis that age and tissue ischemia alter the balance of endogenous antioxidant enzymes. Using a bipedicled skin flap model, ischemic and non-ischemic wounds were created on young and aged rats. Wound closure and the balance of the critical antioxidants superoxide dismutase and glutathione in the wound bed were determined. Ischemia delayed wound closure significantly more in aged rats. Lower superoxide dismutase 2 and glutathione in non-ischemic wounds of aged rats indicate a basal deficit due to age alone. Ischemic wounds from aged rats had lower superoxide dismutase 2 protein and activity initially, coupled with decreased ratios of reduced/oxidized glutathione and lower glutathione peroxidase activity. De novo glutathione synthesis, to restore redox balance in aged ischemic wounds, was initiated as evidenced by increased glutamate cysteine ligase. Results demonstrate deficiencies in two antioxidant pathways in aged rats that become exaggerated in ischemic tissue, culminating in profoundly impaired wound healing and prolonged inflammation.

  1. Altered feeding response as a cause for the altered heartbeat rate and locomotor activity of Schistosoma mansoni-infected biomphalaria glabrata.

    PubMed

    Williams, C L; Gilbertson, D E

    1983-08-01

    Biomphalaria glabrata infected with Schistosoma mansoni for 33 days fed more often than uninfected snails. Whereas uninfected snails had nocturnal increases in feeding, snails with a 33-day-old infection of S. mansoni fed as often during the day as in the night. Using direct observation and film analysis, we found that feeding increased the heartbeat rate and locomotor activity of B. glabrata. When snails were allowed to feed ad lib., infected snails had higher heartbeat rates than uninfected snails both during the day (P less than 0.01) and the night (P less than 0.001). However, when the snails were deprived of food for 24 hr, infected snails had slightly higher heartbeat rates than uninfected snails only during the day (P less than 0.05). There was no difference between the heartbeat rates of feeding, infected snails and the heartbeat rates of uninfected snails that were starved for 8 hr, and then allowed to feed. Uninfected snails had nocturnal increases in heartbeat rate regardless of feeding schedule, but infected snails had greater nighttime heartbeat rate than daytime heartbeat rate only when they were not allowed to feed. Infected snails had less nocturnal locomotor activity than uninfected snails when feeding, but there was no difference between the locomotor activity of infected and uninfected snails when the snails were deprived of food for 24 hr. Absence of food also resulted in an increased nighttime to daytime ratio of locomotor activity of infected snails. These results suggest that the increased heartbeat rate and altered rhythms of heartbeat rate and locomotor activity in B. glabrata infected with S. mansoni for 33 days were caused by the altered feeding response of these snails.

  2. Reproductive Experience Alters Neural and Behavioural Responses to Acute Oestrogen Receptor α Activation

    PubMed Central

    Byrnes, E. M.; Casey, K.; Carini, L. M.; Bridges, R. S.

    2014-01-01

    Reproductive experience (i.e. parturition and lactation) leads to persistent alterations in anxietylike behaviour that are influenced by the oestrous cycle. We recently found that repeated administration of the selective oestrogen receptors (ER)α agonist propyl-pyrazole triol (PPT) results in anxiolytic-like behaviours on the elevated plus maze (EPM) in primiparous (but not nulliparous) female rats. The present study examined the effects of the acute administration of PPT on EPM behaviour in primiparous and aged-matched, nulliparous female rats. In addition, corticosterone secretion, corticotrophin-releasing hormone (CRH) gene expression and expression of the immediate early gene product Fos in the paraventricular nucleus (PVN) and amygdala were measured either after EPM testing or in home cage controls. Acute PPT administration significantly modified EPM behaviour as a function of reproductive experience, with nulliparous females tending toward increased anxiety-like behaviours and primiparous females tending toward decreased anxiety-like behaviours. In home cage controls, PPT increased corticosterone secretion in all females; however, both vehicle- and PPT-treated, primiparous females had reduced corticosterone levels compared to their nulliparous counterparts. Significant effects of PPT on CRH mRNA within the PVN were observed after the administration of PPT but only in primiparous females tested on the EPM. PPT also increased Fos expression within the PVN of EPM-exposed females; however, both vehicle- and PPT-treated primiparous females had reduced Fos expression compared to nulliparous females. In the amygdala, PPT increased Fos immunore-activity in the central but not the medial or basolateral amygdala, although these effects were only observed in home cage females. Additionally, both vehicle- and PPT-treated home cage, primiparous females had increased Fos in the central nucleus of the amygdala compared to nullip-arous controls. Overall, these data

  3. Alterations in lower limb multimuscle activation patterns during stair climbing in female total knee arthroplasty patients

    PubMed Central

    von Tscharner, V.; Hutchison, C.; Ronsky, J. L.

    2015-01-01

    Total knee arthroplasty (TKA) patients commonly experience neuromuscular adaptations that may affect stair climbing competence. This study identified multimuscle pattern (MMP) changes in postoperative female TKA patients during stair climbing with a support vector machine (SVM). It was hypothesized that TKA patients adopt temporal and spectral muscle activation characteristics indicative of muscle atrophy and cocontraction strategies. Nineteen female subjects [10 unilateral sex-specific TKAs, 62.2 ± 8.6 yr, body mass index (BMI) 28.2 ± 5.4 kg/m2; 9 healthy control subjects, 61.4 ± 7.4 yr, BMI 25.6 ± 2.4 kg/m2] were recruited. Surface electromyograms (EMGs) were obtained for seven lower limb muscles of the affected limb of TKA subjects and a randomly assigned limb for control subjects during stair climbing. Stance phase (±30%) EMG data were wavelet transformed and normalized to total power. Data across all muscles were combined to form MMPs and analyzed with a SVM. Statistical analysis was performed with binomial tests, independent group t-tests, or independent group Mann-Whitney U-tests in SPSS (P < 0.05). SVM results indicated significantly altered muscle activation patterns in the TKA group for biceps femoris (recognition rate 84.2%), semitendinosus (recognition rate 73.7%), gastrocnemius (recognition rate 68.4%), and tibialis anterior (recognition rate 68.4%). Further analysis identified no significant differences in spectral activation characteristics between groups. Temporal adaptations, indicative of cocontraction strategies, were, however, evident in TKA MMPs. This approach may provide a valuable tool for clinical neuromuscular function assessment and rehabilitation monitoring. PMID:26354313

  4. Benzene's metabolites alter c-MYB activity via reactive oxygen species in HD3 cells

    SciTech Connect

    Wan, Joanne; Winn, Louise M. . E-mail: winnl@queensu.ca

    2007-07-15

    Benzene is a known leukemogen that is metabolized to form reactive intermediates and reactive oxygen species (ROS). The c-Myb oncoprotein is a transcription factor that has a critical role in hematopoiesis. c-Myb transcript and protein have been overexpressed in a number of leukemias and cancers. Given c-Myb's role in hematopoiesis and leukemias, it is hypothesized that benzene interferes with the c-Myb signaling pathway and that this involves ROS. To investigate our hypothesis, we evaluated whether benzene, 1,4-benzoquinone, hydroquinone, phenol, and catechol generated ROS in chicken erythroblast HD3 cells, as measured by 5-(and-6)-chloromethyl-2',7'-dichlorodihydrofluorescein diacetate (DCFDA) and dihydrorhodamine-123 (DHR-123), and whether the addition of 100 U/ml of the antioxidating enzyme superoxide dismutase (SOD) could prevent ROS generation. Reduced to oxidized glutathione ratios (GSH:GSSG) were also assessed as well as hydroquinone and benzoquinone's effects on c-Myb protein levels and activation of a transiently transfected reporter construct. Finally we attempted to abrogate benzene metabolite mediated increases in c-Myb activity with the use of SOD. We found that benzoquinone, hydroquinone, and catechol increased DCFDA fluorescence, increased DHR-123 fluorescence, decreased GSH:GSSG ratios, and increased reporter construct expression after 24 h of exposure. SOD was able to prevent DCFDA fluorescence and c-Myb activity caused by benzoquinone and hydroquinone only. These results are consistent with other studies, which suggest metabolite differences in benzene-mediated toxicity. More importantly, this study supports the hypothesis that benzene may mediate its toxicity through ROS-mediated alterations in the c-Myb signaling pathway.

  5. Regulation of calpain activity in rat brain with altered Ca2+ homeostasis.

    PubMed

    Averna, Monica; Stifanese, Roberto; De Tullio, Roberta; Passalacqua, Mario; Defranchi, Enrico; Salamino, Franca; Melloni, Edon; Pontremoli, Sandro

    2007-01-26

    Activation of calpain occurs as an early event in correlation with an increase in [Ca2+]i induced in rat brain upon treatment with a high salt diet for a prolonged period of time. The resulting sequential events have been monitored in the brain of normal and hypertensive rats of the Milan strain, diverging for a constitutive alteration in the level of [Ca2+]i found to be present in nerve cells of hypertensive animals. After 2 weeks of treatment, the levels of the plasma membrane Ca2+-ATPase and of native calpastatin are profoundly decreased. These degradative processes, more pronounced in the brain of hypertensive rats, are progressively and efficiently compensated in the brain of both rat strains by different incoming mechanisms. Along with calpastatin degradation, 15-kDa still-active inhibitory fragments are accumulated, capable of efficiently replacing the loss of native inhibitor molecules. A partial return to a more efficient control of Ca2+ homeostasis occurs in parallel, assured by an early increase in the expression of Ca2+-ATPase and of calpastatin, both producing, after 12 weeks of a high salt (sodium) diet, the restoration of almost original levels of the Ca2+ pump and of significant amounts of native inhibitor molecules. Thus, conservative calpastatin fragmentation, associated with an increased expression of Ca2+-ATPase and of the calpain natural inhibitor, has been demonstrated to occur in vivo in rat brain. This represents a sequential adaptive response capable of overcoming the effects of calpain activation induced by a moderate long term elevation of [Ca2+]i.

  6. Alterations in erythrocyte membrane fluidity and Na+/K+ -ATPase activity in chronic alcoholics.

    PubMed

    Maturu, Paramahamsa; Vaddi, Damodara Reddy; Pannuru, Padmavathi; Nallanchakravarthula, Varadacharyulu

    2010-06-01

    Ethanol disorders biological membranes causing perturbations in the bilayer and also by altering the physicochemical properties of membrane lipids. But, chronic alcohol consumption also increases nitric oxide (NO) production. There was no systemic study was done related to alcohol-induced production of NO and consequent formation of peroxynitrite mediated changes in biophysical and biochemical properties, structure, composition, integrity and function of erythrocyte membranes in chronic alcoholics. Hence, keeping all these conditions in mind the present study was undertaken to investigate the role of over produced nitric oxide on red cell membrane physicochemical properties in chronic alcoholics. Human male volunteers aged 44 +/- 6 years with similar dietary habits were divided into two groups, namely nonalcoholic controls and chronic alcoholics (~125 g of alcohol at least five times per week for the past 10-12 years). Elevated nitrite and nitrate levels in plasma and lysate, changes in erythrocyte membrane individual phospholipid composition, increased lipid peroxidation, protein carbonyls, cholesterol and phospholipids ratio (C/P ratio) and anisotropic value (gamma) with decreased sulfhydryl groups and Na(+)/K(+)-ATPase activity in alcoholics was evident from this study. RBC lysate NO was positively correlated with C/P ratio (r = 0.547) and anisotropic (gamma) value (r = 0.428), Na(+)/K(+)-ATPase activity was negatively correlated with RBC lysate NO (r = -0.372) and anisotropic (gamma) value (r = -0.624) in alcoholics. Alcohol-induced overproduction of nitric oxide reacts with superoxide radicals to produce peroxynitrite, which appears to be responsible for changes in erythrocyte membrane lipids and the activity of Na(+)/K(+)-ATPase.

  7. The time course of altered brain activity during 7-day simulated microgravity.

    PubMed

    Liao, Yang; Lei, Meiying; Huang, Haibo; Wang, Chuang; Duan, Jiaobo; Li, Hongzheng; Liu, Xufeng

    2015-01-01

    Microgravity causes multiple changes in physical and mental levels in humans, which can induce performance deficiency among astronauts. Studying the variations in brain activity that occur during microgravity would help astronauts to deal with these changes. In the current study, resting-state functional magnetic resonance imaging (rs-fMRI) was used to observe the variations in brain activity during a 7-day head down tilt (HDT) bed rest, which is a common and reliable model for simulated microgravity. The amplitudes of low frequency fluctuation (ALFF) of twenty subjects were recorded pre-head down tilt (pre-HDT), during a bed rest period (HDT0), and then each day in the HDT period (HDT1-HDT7). One-way analysis of variance (ANOVA) of the ALFF values over these 8 days was used to test the variation across time period (p < 0.05, corrected). Compared to HDT0, subjects presented lower ALFF values in the posterior cingulate cortex (PCC) and higher ALFF values in the anterior cingulate cortex (ACC) during the HDT period, which may partially account for the lack of cognitive flexibility and alterations in autonomic nervous system seen among astronauts in microgravity. Additionally, the observed improvement in function in CPL during the HDT period may play a compensatory role to the functional decline in the paracentral lobule to sustain normal levels of fine motor control for astronauts in a microgravity environment. Above all, those floating brain activities during 7 days of simulated microgravity may indicate that the brain self-adapts to help astronauts adjust to the multiple negative stressors encountered in a microgravity environment. PMID:26029071

  8. Post-Spaceflight (STS-135) Mouse Splenocytes Demonstrate Altered Activation Properties and Surface Molecule Expression.

    PubMed

    Hwang, Shen-An; Crucian, Brian; Sams, Clarence; Actor, Jeffrey K

    2015-01-01

    Alterations in immune function have been documented during or post-spaceflight and in ground based models of microgravity. Identification of immune parameters that are dysregulated during spaceflight is an important step in mitigating crew health risks during deep space missions. The in vitro analysis of leukocyte activity post-spaceflight in both human and animal species is primarily focused on lymphocytic function. This report completes a broader spectrum analysis of mouse lymphocyte and monocyte changes post 13 days orbital flight (mission STS-135). Analysis includes an examination in surface markers for cell activation, and antigen presentation and co-stimulatory molecules. Cytokine production was measured after stimulation with T-cell mitogen or TLR-2, TLR-4, or TLR-5 agonists. Splenocyte surface marker analysis immediate post-spaceflight and after in vitro culture demonstrated unique changes in phenotypic populations between the flight mice and matched treatment ground controls. Post-spaceflight splenocytes (flight splenocytes) had lower expression intensity of CD4+CD25+ and CD8+CD25+ cells, lower percentage of CD11c+MHC II+ cells, and higher percentage of CD11c+MHC I+ populations compared to ground controls. The flight splenocytes demonstrated an increase in phagocytic activity. Stimulation with ConA led to decrease in CD4+ population but increased CD4+CD25+ cells compared to ground controls. Culturing with TLR agonists led to a decrease in CD11c+ population in splenocytes isolated from flight mice compared to ground controls. Consequently, flight splenocytes with or without TLR-agonist stimulation showed a decrease in CD11c+MHC I+, CD11c+MHC II+, and CD11c+CD86+ cells compared to ground controls. Production of IFN-γ was decreased and IL-2 was increased from ConA stimulated flight splenocytes. This study demonstrated that expression of surface molecules can be affected by conditions of spaceflight and impaired responsiveness persists under culture

  9. Post-Spaceflight (STS-135) Mouse Splenocytes Demonstrate Altered Activation Properties and Surface Molecule Expression

    PubMed Central

    Crucian, Brian; Sams, Clarence

    2015-01-01

    Alterations in immune function have been documented during or post-spaceflight and in ground based models of microgravity. Identification of immune parameters that are dysregulated during spaceflight is an important step in mitigating crew health risks during deep space missions. The in vitro analysis of leukocyte activity post-spaceflight in both human and animal species is primarily focused on lymphocytic function. This report completes a broader spectrum analysis of mouse lymphocyte and monocyte changes post 13 days orbital flight (mission STS-135). Analysis includes an examination in surface markers for cell activation, and antigen presentation and co-stimulatory molecules. Cytokine production was measured after stimulation with T-cell mitogen or TLR-2, TLR-4, or TLR-5 agonists. Splenocyte surface marker analysis immediate post-spaceflight and after in vitro culture demonstrated unique changes in phenotypic populations between the flight mice and matched treatment ground controls. Post-spaceflight splenocytes (flight splenocytes) had lower expression intensity of CD4+CD25+ and CD8+CD25+ cells, lower percentage of CD11c+MHC II+ cells, and higher percentage of CD11c+MHC I+ populations compared to ground controls. The flight splenocytes demonstrated an increase in phagocytic activity. Stimulation with ConA led to decrease in CD4+ population but increased CD4+CD25+ cells compared to ground controls. Culturing with TLR agonists led to a decrease in CD11c+ population in splenocytes isolated from flight mice compared to ground controls. Consequently, flight splenocytes with or without TLR-agonist stimulation showed a decrease in CD11c+MHC I+, CD11c+MHC II+, and CD11c+CD86+ cells compared to ground controls. Production of IFN-γ was decreased and IL-2 was increased from ConA stimulated flight splenocytes. This study demonstrated that expression of surface molecules can be affected by conditions of spaceflight and impaired responsiveness persists under culture

  10. The time course of altered brain activity during 7-day simulated microgravity

    PubMed Central

    Liao, Yang; Lei, Meiying; Huang, Haibo; Wang, Chuang; Duan, Jiaobo; Li, Hongzheng; Liu, Xufeng

    2015-01-01

    Microgravity causes multiple changes in physical and mental levels in humans, which can induce performance deficiency among astronauts. Studying the variations in brain activity that occur during microgravity would help astronauts to deal with these changes. In the current study, resting-state functional magnetic resonance imaging (rs-fMRI) was used to observe the variations in brain activity during a 7-day head down tilt (HDT) bed rest, which is a common and reliable model for simulated microgravity. The amplitudes of low frequency fluctuation (ALFF) of twenty subjects were recorded pre-head down tilt (pre-HDT), during a bed rest period (HDT0), and then each day in the HDT period (HDT1–HDT7). One-way analysis of variance (ANOVA) of the ALFF values over these 8 days was used to test the variation across time period (p < 0.05, corrected). Compared to HDT0, subjects presented lower ALFF values in the posterior cingulate cortex (PCC) and higher ALFF values in the anterior cingulate cortex (ACC) during the HDT period, which may partially account for the lack of cognitive flexibility and alterations in autonomic nervous system seen among astronauts in microgravity. Additionally, the observed improvement in function in CPL during the HDT period may play a compensatory role to the functional decline in the paracentral lobule to sustain normal levels of fine motor control for astronauts in a microgravity environment. Above all, those floating brain activities during 7 days of simulated microgravity may indicate that the brain self-adapts to help astronauts adjust to the multiple negative stressors encountered in a microgravity environment. PMID:26029071

  11. Frequency of climbing behavior as a predictor of altered motor activity in rat forced swimming test.

    PubMed

    Vieira, Cíntia; De Lima, Thereza C M; Carobrez, Antonio de Pádua; Lino-de-Oliveira, Cilene

    2008-11-14

    Previous work has shown that the frequency of climbing behavior in rats submitted to the forced swimming test (FST) correlated to the section's crosses in the open field test, which suggest it might be taken as a predictor of motor activity in rat FST. To investigate this proposal, the frequency, duration, as well as the ratio duration/frequency for each behavior expressed in the FST (immobility, swimming and climbing) were compared in animals treated with a motor stimulant, caffeine (CAF), and the antidepressant, clomipramine (CLM). Male Wistar rats were submitted to 15min of forced swimming (pre-test) and 24h later received saline (SAL, 1ml/kg, i.p.) or CAF (6.5mg/kg, i.p.) 30min prior a 5-min session (test) of FST. To validate experimental procedures, an additional group of rats received three injections of SAL (1ml/kg, i.p.) or clomipramine (CLM, 10mg/kg, i.p.) between the pre-test and test sessions. The results of the present study showed that both drugs, CLM and CAF, significantly reduced the duration of immobility and significantly increased the duration of swimming. In addition, CAF significantly decreased the ratio of immobility, and CLM significantly increased the ratio of swimming and climbing. Moreover, CLM significantly increased the duration of climbing but only CAF increased the frequency of climbing. Thus, it seems that the frequency of climbing could be a predictor of altered motor activity scored directly in the FST. Further, we believe that this parameter could be useful for fast and reliable discrimination between antidepressant drugs and stimulants of motor activity.

  12. Complementary PLS and KNN algorithms for improved 3D-QSDAR consensus modeling of AhR binding

    PubMed Central

    2013-01-01

    Multiple validation techniques (Y-scrambling, complete training/test set randomization, determination of the dependence of R2test on the number of randomization cycles, etc.) aimed to improve the reliability of the modeling process were utilized and their effect on the statistical parameters of the models was evaluated. A consensus partial least squares (PLS)-similarity based k-nearest neighbors (KNN) model utilizing 3D-SDAR (three dimensional spectral data-activity relationship) fingerprint descriptors for prediction of the log(1/EC50) values of a dataset of 94 aryl hydrocarbon receptor binders was developed. This consensus model was constructed from a PLS model utilizing 10 ppm x 10 ppm x 0.5 Å bins and 7 latent variables (R2test of 0.617), and a KNN model using 2 ppm x 2 ppm x 0.5 Å bins and 6 neighbors (R2test of 0.622). Compared to individual models, improvement in predictive performance of approximately 10.5% (R2test of 0.685) was observed. Further experiments indicated that this improvement is likely an outcome of the complementarity of the information contained in 3D-SDAR matrices of different granularity. For similarly sized data sets of Aryl hydrocarbon (AhR) binders the consensus KNN and PLS models compare favorably to earlier reports. The ability of 3D-QSDAR (three dimensional quantitative spectral data-activity relationship) to provide structural interpretation was illustrated by a projection of the most frequently occurring bins on the standard coordinate space, thus allowing identification of structural features related to toxicity. PMID:24257141

  13. Improved calibration of IMU biases in analytic coarse alignment for AHRS

    NASA Astrophysics Data System (ADS)

    Lu, Jiazhen; Lei, Chaohua; Li, Baoguo; Wen, Ting

    2016-07-01

    An improved method for the inertial measurement unit (IMU) calibration of coarse alignment for the low-accuracy attitude heading reference system (AHRS) is proposed in this paper. The sensitivities of the Euler angles with respect to the inertial sensor biases are studied based on the analytic coarse alignment principle, and the errors of earth rotation rate and local gravity in the body frame caused by initial attitude error are analyzed. Then, an improved analytic coarse alignment algorithm with accelerometer and gyro bias calibration in an arbitrary three-position is proposed. Simulation and experiment results show that the novel method can calibrate accelerometer and gyro biases, reduce Euler angle attitude error, and improve navigation precision in practical applications. Moreover, this method can be applied to other low-accuracy inertial navigation systems.

  14. Altered expression of urokinase-type plasminogen activator and plasminogen activator inhibitor in high-risk soft tissue sarcomas.

    PubMed

    Benassi, M S; Ponticelli, F; Azzoni, E; Gamberi, G; Pazzaglia, L; Chiechi, A; Conti, A; Spessotto, P; Scapolan, M; Pignotti, E; Bacchini, P; Picci, P

    2007-09-01

    In recent years, classification of soft-tissue sarcomas (STS) has improved with cytogenetic analyses, but their clinical behavior is still not easily predictable. The aim of this study was to detect alterations in the urokinase-type plasminogen system, involved in tumor growth and invasion, by comparing mRNA levels of its components with those of paired normal tissues, and relating them with patient clinical course. Real-time PCR was performed on human STS cell lines and tissues from highly malignant STS, including leiomyosarcomas and malignant fibrous histiocytomas, to evaluate the expression of urokinase-type plasminogen activator (uPA), uPA receptor (uPAR) and plasminogen activator inhibitor-1 (PAI-1). Immunohistochemistry of gene products was also performed. Median mRNA values of all genes studied were higher in tumors than in paired normal tissues. In agreement with data on STS cell lines, significant up-regulation for uPA and PAI-1 genes compared to reference values was seen. Moreover, different levels of expression were related to histotype and metastatic phenotype. There was accordance between uPA mRNA and protein expression, while immunodetection of PAI-1 product was weak and scattered. Clearly, the controversial role of PAI-1 protein requires further biological analyses, but evident involvement of uPA/PAI-1 gene overexpression in STS malignancy may highlight a molecular defect useful in discriminating STS high-risk patients. PMID:17523079

  15. Access Path to the Ligand Binding Pocket May Play a Role in Xenobiotics Selection by AhR

    PubMed Central

    Szöllősi, Dániel; Erdei, Áron; Gyimesi, Gergely; Magyar, Csaba; Hegedűs, Tamás

    2016-01-01

    Understanding of multidrug binding at the atomic level would facilitate drug design and strategies to modulate drug metabolism, including drug transport, oxidation, and conjugation. Therefore we explored the mechanism of promiscuous binding of small molecules by studying the ligand binding domain, the PAS-B domain of the aryl hydrocarbon receptor (AhR). Because of the low sequence identities of PAS domains to be used for homology modeling, structural features of the widely employed HIF-2α and a more recent suitable template, CLOCK were compared. These structures were used to build AhR PAS-B homology models. We performed molecular dynamics simulations to characterize dynamic properties of the PAS-B domain and the generated conformational ensembles were employed in in silico docking. In order to understand structural and ligand binding features we compared the stability and dynamics of the promiscuous AhR PAS-B to other PAS domains exhibiting specific interactions or no ligand binding function. Our exhaustive in silico binding studies, in which we dock a wide spectrum of ligand molecules to the conformational ensembles, suggest that ligand specificity and selection may be determined not only by the PAS-B domain itself, but also by other parts of AhR and its protein interacting partners. We propose that ligand binding pocket and access channels leading to the pocket play equally important roles in discrimination of endogenous molecules and xenobiotics. PMID:26727491

  16. Lactobacillus bulgaricus OLL1181 activates the aryl hydrocarbon receptor pathway and inhibits colitis.

    PubMed

    Takamura, Takeyuki; Harama, Daisuke; Fukumoto, Suguru; Nakamura, Yuki; Shimokawa, Naomi; Ishimaru, Kayoko; Ikegami, Shuji; Makino, Seiya; Kitamura, Masanori; Nakao, Atsuhito

    2011-10-01

    Increasing evidence suggests that the aryl hydrocarbon receptor (AhR) pathway has an important role in the regulation of inflammatory responses. Most recently, we have shown that the activation of the AhR pathway by a potent AhR agonist inhibits the development of dextran sodium sulfate (DSS)-induced colitis, a model of human ulcerative colitis, by the induction of prostaglandin E2 (PGE2) in the large intestine. Because several strains of probiotic lactic acid bacteria have been reported to inhibit DSS-induced colitis by unidentified mechanisms, we hypothesized that particular strains of lactic acid bacterium might have the potential to activate the AhR pathway, thereby inhibiting DSS-induced colitis. This study investigated whether there are specific lactic acid bacterial strains that can activate the AhR pathway, and if so, whether this AhR-activating potential is associated with suppression of DSS-induced colitis. By using AhR signaling reporter cells, we found that Lactobacillus bulgaricus OLL1181 had the potential to activate the AhR pathway. OLL1181 also induced the mRNA expression of cytochrome P450 family 1A1 (CYP1A1), a target gene of the AhR pathway, in human colon cells, which was inhibited by the addition of an AhR antagonist, α-naphthoflavon (αNF). In addition, mice treated orally with OLL1181 showed an increase in CYP1A1 mRNA expression in the large intestine and amelioration of DSS-induced colitis. Thus, OLL1181 can induce activation of the intestinal AhR pathway and inhibit DSS-induced colitis in mice. This strain of lactic acid bacterium has therefore the potential to activate the AhR pathway, which may be able to suppress colitis.

  17. FINE STRUCTURAL ALTERATIONS OF INTERPHASE NUCLEI OF LYMPHOCYTES STIMULATED TO GROWTH ACTIVITY IN VITRO

    PubMed Central

    Tokuyasu, K.; Madden, S. C.; Zeldis, L. J.

    1968-01-01

    This report describes fine structural changes of interphase nuclei of human peripheral blood lymphocytes stimulated to growth by short-term culture with phytohemagglutinin. Chromatin is found highly labile, its changes accompanying the sequential increases of RNA and DNA synthesis which are known to occur in lymphocyte cultures. In "resting" lymphocytes, abundant condensed chromatin appears as a network of large and small aggregates. Early in the response to phytohemagglutinin, small aggregates disappear during increase of diffuse chromatin regions. Small aggregates soon reappear, probably resulting from disaggregation of large masses of condensed chromatin. Loosened and highly dispersed forms then appear prior to the formation of prophase chromosomes. The loosened state is found by radioautography to be most active in DNA synthesis. Small nucleoli of resting lymphocytes have concentric agranular, fibrillar, and granular zones with small amounts of intranucleolar chromatin. Enlarging interphase nucleoli change chiefly (1) by increase in amount of intranucleolar chromatin and alteration of its state of aggregation and (2) by increase in granular components in close association with fibrillar components. PMID:5699935

  18. Altered motor activity, exploration and anxiety in heterozygous neuregulin 1 mutant mice: implications for understanding schizophrenia.

    PubMed

    Karl, T; Duffy, L; Scimone, A; Harvey, R P; Schofield, P R

    2007-10-01

    Human genetic studies have shown that neuregulin 1 (NRG1) is a potential susceptibility gene for schizophrenia. Nrg1 influences various neurodevelopmental processes, which are potentially related to schizophrenia. The neurodevelopmental theory of schizophrenia suggests that interactions between genetic and environmental factors are responsible for biochemical alterations leading to schizophrenia. To investigate these interactions and to match experimental design with the pathophysiology of schizophrenia, we applied a comprehensive behavioural phenotyping strategy for motor activity, exploration and anxiety in a heterozygous Nrg1 transmembrane domain mutant mouse model (Nrg1 HET) using different housing conditions and age groups. We observed a locomotion- and exploration-related hyperactive phenotype in Nrg1 HETs. Increased age had a locomotion- and exploration-inhibiting effect, which was significantly attenuated in mutant mice. Environmental enrichment (EE) had a stimulating influence on locomotion and exploration. The impact of EE was more pronounced in Nrg1 hypomorphs. Our study also showed a moderate task-specific anxiolytic-like phenotype for Nrg1 HETs, which was influenced by external factors. The behavioural phenotype detected in heterozygous Nrg1 mutant mice is not specific to schizophrenia per se, but the increased sensitivity of mutant mice to exogenous factors is consistent with the pathophysiology of schizophrenia and the neurodevelopmental theory. Our findings reinforce the importance of carefully controlling experimental designs for external factors and of comprehensive, integrative phenotyping strategies. Thus, Nrg1 HETs may, in combination with other genetic and drug models, help to clarify pathophysiological mechanisms behind schizophrenia.

  19. Loss of UCP2 attenuates mitochondrial dysfunction without altering ROS production and uncoupling activity.

    PubMed

    Kukat, Alexandra; Dogan, Sukru Anil; Edgar, Daniel; Mourier, Arnaud; Jacoby, Christoph; Maiti, Priyanka; Mauer, Jan; Becker, Christina; Senft, Katharina; Wibom, Rolf; Kudin, Alexei P; Hultenby, Kjell; Flögel, Ulrich; Rosenkranz, Stephan; Ricquier, Daniel; Kunz, Wolfram S; Trifunovic, Aleksandra

    2014-06-01

    Although mitochondrial dysfunction is often accompanied by excessive reactive oxygen species (ROS) production, we previously showed that an increase in random somatic mtDNA mutations does not result in increased oxidative stress. Normal levels of ROS and oxidative stress could also be a result of an active compensatory mechanism such as a mild increase in proton leak. Uncoupling protein 2 (UCP2) was proposed to play such a role in many physiological situations. However, we show that upregulation of UCP2 in mtDNA mutator mice is not associated with altered proton leak kinetics or ROS production, challenging the current view on the role of UCP2 in energy metabolism. Instead, our results argue that high UCP2 levels allow better utilization of fatty acid oxidation resulting in a beneficial effect on mitochondrial function in heart, postponing systemic lactic acidosis and resulting in longer lifespan in these mice. This study proposes a novel mechanism for an adaptive response to mitochondrial cardiomyopathy that links changes in metabolism to amelioration of respiratory chain deficiency and longer lifespan. PMID:24945157

  20. Subchronic phencyclidine in rats: alterations in locomotor activity, maze performance, and GABA(A) receptor binding.

    PubMed

    Beninger, Richard J; Beuk, Jonathan; Banasikowski, Tomek J; van Adel, Michael; Boivin, Gregory A; Reynolds, James N

    2010-02-01

    Phencyclidine (PCP), an antagonist at the N-methyl-D-aspartate subtype of ionotropic glutamatergic receptors, decreases gamma-aminobutyric acid (GABA)ergic inhibition, suggesting that changes in GABAergic receptor function underlie behavioral and cognitive deficits resulting from repeated administration of PCP. To test this hypothesis, male Sprague-Dawley rats treated with PCP (4.5 mg/kg, intraperitoneal, twice a day for 7 consecutive days) or saline were tested in behavioral and cognitive tasks 7 days after injections. The PCP group showed increased amphetamine (1.5 mg/kg)-stimulated locomotor activity, and exhibited a greater number of errors in the double Y-maze memory task, when compared with controls. Subchronic PCP treatment increased [H]muscimol-binding sites and decreased affinity for [H]muscimol binding in frontal cortex, hippocampus, and striatum in comparison with controls. There were no changes in the expression of glutamic acid decarboxylase or the GABA membrane transporter protein. These data show that subchronic PCP administration induces an impaired performance of a previously learned task and an enhanced response to amphetamine in the rat. The observed changes in GABAA receptors in the rat brain are consistent with the notion that alterations in GABAergic receptor function contribute to the behavioral and cognitive impairments associated with repeated exposure to PCP. PMID:19949321

  1. A Rare Myelin Protein Zero (MPZ) Variant Alters Enhancer Activity In Vitro and In Vivo

    PubMed Central

    Burzynski, Grzegorz; Huynh, Jimmy; Maduro, Valerie; Hodonsky, Chani J.; Khajavi, Mehrdad; Szigeti, Kinga; Mukkamala, Sandeep; Bessling, Seneca L.; Pavan, William J.; McCallion, Andrew S.; Lupski, James R.; Green, Eric D.

    2010-01-01

    Background Myelin protein zero (MPZ) is a critical structural component of myelin in the peripheral nervous system. The MPZ gene is regulated, in part, by the transcription factors SOX10 and EGR2. Mutations in MPZ, SOX10, and EGR2 have been implicated in demyelinating peripheral neuropathies, suggesting that components of this transcriptional network are candidates for harboring disease-causing mutations (or otherwise functional variants) that affect MPZ expression. Methodology We utilized a combination of multi-species sequence comparisons, transcription factor-binding site predictions, targeted human DNA re-sequencing, and in vitro and in vivo enhancer assays to study human non-coding MPZ variants. Principal Findings Our efforts revealed a variant within the first intron of MPZ that resides within a previously described SOX10 binding site is associated with decreased enhancer activity, and alters binding of nuclear proteins. Additionally, the genomic segment harboring this variant directs tissue-relevant reporter gene expression in zebrafish. Conclusions This is the first reported MPZ variant within a cis-acting transcriptional regulatory element. While we were unable to implicate this variant in disease onset, our data suggests that similar non-coding sequences should be screened for mutations in patients with neurological disease. Furthermore, our multi-faceted approach for examining the functional significance of non-coding variants can be readily generalized to study other loci important for myelin structure and function. PMID:21179557

  2. Activity and High-Order Effective Connectivity Alterations in Sanfilippo C Patient-Specific Neuronal Networks

    PubMed Central

    Canals, Isaac; Soriano, Jordi; Orlandi, Javier G.; Torrent, Roger; Richaud-Patin, Yvonne; Jiménez-Delgado, Senda; Merlin, Simone; Follenzi, Antonia; Consiglio, Antonella; Vilageliu, Lluïsa; Grinberg, Daniel; Raya, Angel

    2015-01-01

    Summary Induced pluripotent stem cell (iPSC) technology has been successfully used to recapitulate phenotypic traits of several human diseases in vitro. Patient-specific iPSC-based disease models are also expected to reveal early functional phenotypes, although this remains to be proved. Here, we generated iPSC lines from two patients with Sanfilippo type C syndrome, a lysosomal storage disorder with inheritable progressive neurodegeneration. Mature neurons obtained from patient-specific iPSC lines recapitulated the main known phenotypes of the disease, not present in genetically corrected patient-specific iPSC-derived cultures. Moreover, neuronal networks organized in vitro from mature patient-derived neurons showed early defects in neuronal activity, network-wide degradation, and altered effective connectivity. Our findings establish the importance of iPSC-based technology to identify early functional phenotypes, which can in turn shed light on the pathological mechanisms occurring in Sanfilippo syndrome. This technology also has the potential to provide valuable readouts to screen compounds, which can prevent the onset of neurodegeneration. PMID:26411903

  3. Cumulative Industrial Activity Alters Lotic Fish Assemblages in Two Boreal Forest Watersheds of Alberta, Canada

    NASA Astrophysics Data System (ADS)

    Scrimgeour, Garry J.; Hvenegaard, Paul J.; Tchir, John

    2008-12-01

    We evaluated the cumulative effects of land use disturbance resulting from forest harvesting, and exploration and extraction of oil and gas resources on the occurrence and structure of stream fish assemblages in the Kakwa and Simonette watersheds in Alberta, Canada. Logistic regression models showed that the occurrence of numerically dominant species in both watersheds was related to two metrics defining industrial activity (i.e., percent disturbance and road density), in addition to stream wetted width, elevation, reach slope, and percent fines. Occurrences of bull trout, slimy sculpin, and white sucker were negatively related to percent disturbance and that of Arctic grayling, and mountain whitefish were positively related to percent disturbance and road density. Assessments of individual sites showed that 76% of the 74 and 46 test sites in the Kakwa and Simonette watersheds were possibly impaired or impaired. Impaired sites in the Kakwa Watershed supported lower densities of bull trout, mountain whitefish, and rainbow trout, but higher densities of Arctic grayling compared to appropriate reference sites. Impaired sites in the Simonette Watershed supported lower densities of bull trout, but higher densities of lake chub compared to reference sites. Our data suggest that current levels of land use disturbance alters the occurrence and structure of stream fish assemblages.

  4. Stress-induced alterations of left-right electrodermal activity coupling indexed by pointwise transinformation.

    PubMed

    Světlák, M; Bob, P; Roman, R; Ježek, S; Damborská, A; Chládek, J; Shaw, D J; Kukleta, M

    2013-01-01

    In this study, we tested the hypothesis that experimental stress induces a specific change of left-right electrodermal activity (EDA) coupling pattern, as indexed by pointwise transinformation (PTI). Further, we hypothesized that this change is associated with scores on psychometric measures of the chronic stress-related psychopathology. Ninety-nine university students underwent bilateral measurement of EDA during rest and stress-inducing Stroop test and completed a battery of self-report measures of chronic stress-related psychopathology. A significant decrease in the mean PTI value was the prevalent response to the stress conditions. No association between chronic stress and PTI was found. Raw scores of psychometric measures of stress-related psychopathology had no effect on either the resting levels of PTI or the amount of stress-induced PTI change. In summary, acute stress alters the level of coupling pattern of cortico-autonomic influences on the left and right sympathetic pathways to the palmar sweat glands. Different results obtained using the PTI, EDA laterality coefficient, and skin conductance level also show that the PTI algorithm represents a new analytical approach to EDA asymmetry description. PMID:24359433

  5. Loss of UCP2 attenuates mitochondrial dysfunction without altering ROS production and uncoupling activity.

    PubMed

    Kukat, Alexandra; Dogan, Sukru Anil; Edgar, Daniel; Mourier, Arnaud; Jacoby, Christoph; Maiti, Priyanka; Mauer, Jan; Becker, Christina; Senft, Katharina; Wibom, Rolf; Kudin, Alexei P; Hultenby, Kjell; Flögel, Ulrich; Rosenkranz, Stephan; Ricquier, Daniel; Kunz, Wolfram S; Trifunovic, Aleksandra

    2014-06-01

    Although mitochondrial dysfunction is often accompanied by excessive reactive oxygen species (ROS) production, we previously showed that an increase in random somatic mtDNA mutations does not result in increased oxidative stress. Normal levels of ROS and oxidative stress could also be a result of an active compensatory mechanism such as a mild increase in proton leak. Uncoupling protein 2 (UCP2) was proposed to play such a role in many physiological situations. However, we show that upregulation of UCP2 in mtDNA mutator mice is not associated with altered proton leak kinetics or ROS production, challenging the current view on the role of UCP2 in energy metabolism. Instead, our results argue that high UCP2 levels allow better utilization of fatty acid oxidation resulting in a beneficial effect on mitochondrial function in heart, postponing systemic lactic acidosis and resulting in longer lifespan in these mice. This study proposes a novel mechanism for an adaptive response to mitochondrial cardiomyopathy that links changes in metabolism to amelioration of respiratory chain deficiency and longer lifespan.

  6. Loss of UCP2 Attenuates Mitochondrial Dysfunction without Altering ROS Production and Uncoupling Activity

    PubMed Central

    Kukat, Alexandra; Dogan, Sukru Anil; Edgar, Daniel; Mourier, Arnaud; Jacoby, Christoph; Maiti, Priyanka; Mauer, Jan; Becker, Christina; Senft, Katharina; Wibom, Rolf; Kudin, Alexei P.; Hultenby, Kjell; Flögel, Ulrich; Rosenkranz, Stephan; Ricquier, Daniel; Kunz, Wolfram S.; Trifunovic, Aleksandra

    2014-01-01

    Although mitochondrial dysfunction is often accompanied by excessive reactive oxygen species (ROS) production, we previously showed that an increase in random somatic mtDNA mutations does not result in increased oxidative stress. Normal levels of ROS and oxidative stress could also be a result of an active compensatory mechanism such as a mild increase in proton leak. Uncoupling protein 2 (UCP2) was proposed to play such a role in many physiological situations. However, we show that upregulation of UCP2 in mtDNA mutator mice is not associated with altered proton leak kinetics or ROS production, challenging the current view on the role of UCP2 in energy metabolism. Instead, our results argue that high UCP2 levels allow better utilization of fatty acid oxidation resulting in a beneficial effect on mitochondrial function in heart, postponing systemic lactic acidosis and resulting in longer lifespan in these mice. This study proposes a novel mechanism for an adaptive response to mitochondrial cardiomyopathy that links changes in metabolism to amelioration of respiratory chain deficiency and longer lifespan. PMID:24945157

  7. Activity and High-Order Effective Connectivity Alterations in Sanfilippo C Patient-Specific Neuronal Networks.

    PubMed

    Canals, Isaac; Soriano, Jordi; Orlandi, Javier G; Torrent, Roger; Richaud-Patin, Yvonne; Jiménez-Delgado, Senda; Merlin, Simone; Follenzi, Antonia; Consiglio, Antonella; Vilageliu, Lluïsa; Grinberg, Daniel; Raya, Angel

    2015-10-13

    Induced pluripotent stem cell (iPSC) technology has been successfully used to recapitulate phenotypic traits of several human diseases in vitro. Patient-specific iPSC-based disease models are also expected to reveal early functional phenotypes, although this remains to be proved. Here, we generated iPSC lines from two patients with Sanfilippo type C syndrome, a lysosomal storage disorder with inheritable progressive neurodegeneration. Mature neurons obtained from patient-specific iPSC lines recapitulated the main known phenotypes of the disease, not present in genetically corrected patient-specific iPSC-derived cultures. Moreover, neuronal networks organized in vitro from mature patient-derived neurons showed early defects in neuronal activity, network-wide degradation, and altered effective connectivity. Our findings establish the importance of iPSC-based technology to identify early functional phenotypes, which can in turn shed light on the pathological mechanisms occurring in Sanfilippo syndrome. This technology also has the potential to provide valuable readouts to screen compounds, which can prevent the onset of neurodegeneration.

  8. Influence of altered precipitation pattern on greenhouse gas emissions and soil enzyme activities in Pannonian soils

    NASA Astrophysics Data System (ADS)

    Forstner, Stefan Johannes; Michel, Kerstin; Berthold, Helene; Baumgarten, Andreas; Wanek, Wolfgang; Zechmeister-Boltenstern, Sophie; Kitzler, Barbara

    2013-04-01

    Precipitation patterns are likely to be altered due to climate change. Recent models predict a reduction of mean precipitation during summer accompanied by a change in short-term precipitation variability for central Europe. Correspondingly, the risk for summer drought is likely to increase. This may especially be valid for regions which already have the potential for rare, but strong precipitation events like eastern Austria. Given that these projections hold true, soils in this area will receive water irregularly in few, heavy rainfall events and be subjected to long-lasting dry periods in between. This pattern of drying/rewetting can alter soil greenhouse gas fluxes, creating a potential feedback mechanism for climate change. Microorganisms are the key players in most soil carbon (C) and nitrogen (N) transformation processes including greenhouse gas exchange. A conceptual model proposed by Schimel and colleagues (2007) links microbial stress-response physiology to ecosystem-scale biogeochemical processes: In order to cope with decreasing soil water potential, microbes modify resource allocation patterns from growth to survival. However, it remains unclear how microbial resource acquisition via extracellular enzymes and microbial-controlled greenhouse gas fluxes respond to water stress induced by soil drying/rewetting. We designed a laboratory experiment to test for effects of multiple drying/rewetting cycles on soil greenhouse gas fluxes (CO2, CH4, N2O, NO), microbial biomass and extracellular enzyme activity. Three soils representing the main soil types of eastern Austria were collected in June 2012 at the Lysimeter Research Station of the Austrian Agency for Health and Food Safety (AGES) in Vienna. Soils were sieved to 2mm, filled in steel cylinders and equilibrated for one week at 50% water holding capacity (WHC) for each soil. Then soils were separated into two groups: One group received water several times per week (C=control), the other group received

  9. The effect of NGATHA altered activity on auxin signaling pathways within the Arabidopsis gynoecium

    PubMed Central

    Martínez-Fernández, Irene; Sanchís, Sofía; Marini, Naciele; Balanzá, Vicente; Ballester, Patricia; Navarrete-Gómez, Marisa; Oliveira, Antonio C.; Colombo, Lucia; Ferrándiz, Cristina

    2014-01-01

    The four NGATHA genes (NGA) form a small subfamily within the large family of B3-domain transcription factors of Arabidopsis thaliana. NGA genes act redundantly to direct the development of the apical tissues of the gynoecium, the style, and the stigma. Previous studies indicate that NGA genes could exert this function at least partially by directing the synthesis of auxin at the distal end of the developing gynoecium through the upregulation of two different YUCCA genes, which encode flavin monooxygenases involved in auxin biosynthesis. We have compared three developing pistil transcriptome data sets from wildtype, nga quadruple mutants, and a 35S::NGA3 line. The differentially expressed genes showed a significant enrichment for auxin-related genes, supporting the idea of NGA genes as major regulators of auxin accumulation and distribution within the developing gynoecium. We have introduced reporter lines for several of these differentially expressed genes involved in synthesis, transport and response to auxin in NGA gain- and loss-of-function backgrounds. We present here a detailed map of the response of these reporters to NGA misregulation that could help to clarify the role of NGA in auxin-mediated gynoecium morphogenesis. Our data point to a very reduced auxin synthesis in the developing apical gynoecium of nga mutants, likely responsible for the lack of DR5rev::GFP reporter activity observed in these mutants. In addition, NGA altered activity affects the expression of protein kinases that regulate the cellular localization of auxin efflux regulators, and thus likely impact auxin transport. Finally, protein accumulation in pistils of several ARFs was differentially affected by nga mutations or NGA overexpression, suggesting that these accumulation patterns depend not only on auxin distribution but could be also regulated by transcriptional networks involving NGA factors. PMID:24904608

  10. Nerve growth factor alters the sensitivity of rat masseter muscle mechanoreceptors to NMDA receptor activation.

    PubMed

    Wong, Hayes; Dong, Xu-Dong; Cairns, Brian E

    2014-11-01

    Intramuscular injection of nerve growth factor (NGF) into rat masseter muscle induces a local mechanical sensitization that is greater in female than in male rats. The duration of NGF-induced sensitization in male and female rats was associated with an increase in peripheral N-methyl-d-aspartate (NMDA) receptor expression by masseter muscle afferent fibers that began 3 days postinjection. Here, we investigated the functional consequences of increased NMDA expression on the response properties of masseter muscle mechanoreceptors. In vivo extracellular single-unit electrophysiological recordings of trigeminal ganglion neurons innervating the masseter muscle were performed in anesthetized rats 3 days after NGF injection (25 μg/ml, 10 μl) into the masseter muscle. Mechanical activation threshold was assessed before and after intramuscular injection of NMDA. NMDA injection induced mechanical sensitization in both sexes that was increased significantly following NGF injection in the male rats but not in the female rats. However, in female but not male rats, further examination found that preadministration of NGF induced a greater sensitization in slow Aδ-fibers (2-7 m/s) than fast Aδ-fibers (7-12 m/s). This suggests that preadministration of NGF had a different effect on slowly conducting mechanoreceptors in the female rats compared with the male rats. Although previous studies have found an association between estrogenic tone and NMDA activity, no correlation was observed between NMDA-evoked mechanical sensitization and plasma estrogen level. This study suggests NGF alters NMDA-induced mechanical sensitization in the peripheral endings of masseter mechanoreceptors in a sexually dimorphic manner.

  11. Familial Alzheimer’s disease–associated presenilin-1 alters cerebellar activity and calcium homeostasis

    PubMed Central

    Sepulveda-Falla, Diego; Barrera-Ocampo, Alvaro; Hagel, Christian; Korwitz, Anne; Vinueza-Veloz, Maria Fernanda; Zhou, Kuikui; Schonewille, Martijn; Zhou, Haibo; Velazquez-Perez, Luis; Rodriguez-Labrada, Roberto; Villegas, Andres; Ferrer, Isidro; Lopera, Francisco; Langer, Thomas; De Zeeuw, Chris I.; Glatzel, Markus

    2014-01-01

    Familial Alzheimer’s disease (FAD) is characterized by autosomal dominant heritability and early disease onset. Mutations in the gene encoding presenilin-1 (PS1) are found in approximately 80% of cases of FAD, with some of these patients presenting cerebellar damage with amyloid plaques and ataxia with unclear pathophysiology. A Colombian kindred carrying the PS1-E280A mutation is the largest known cohort of PS1-FAD patients. Here, we investigated PS1-E280A–associated cerebellar dysfunction and found that it occurs early in PS1-E208A carriers, while cerebellar signs are highly prevalent in patients with dementia. Postmortem analysis of cerebella of PS1-E280A carrier revealed greater Purkinje cell (PC) loss and more abnormal mitochondria compared with controls. In PS1-E280A tissue, ER/mitochondria tethering was impaired, Ca2+ channels IP3Rs and CACNA1A were downregulated, and Ca2+-dependent mitochondrial transport proteins MIRO1 and KIF5C were reduced. Accordingly, expression of PS1-E280A in a neuronal cell line altered ER/mitochondria tethering and transport compared with that in cells expressing wild-type PS1. In a murine model of PS1-FAD, animals exhibited mild ataxia and reduced PC simple spike activity prior to cerebellar β-amyloid deposition. Our data suggest that impaired calcium homeostasis and mitochondrial dysfunction in PS1-FAD PCs reduces their activity and contributes to motor coordination deficits prior to Aβ aggregation and dementia. We propose that PS1-E280A affects both Ca2+ homeostasis and Aβ precursor processing, leading to FAD and neurodegeneration. PMID:24569455

  12. Removal of visual feedback alters muscle activity and reduces force variability during constant isometric contractions.

    PubMed

    Baweja, Harsimran S; Patel, Bhavini K; Martinkewiz, Julie D; Vu, Julie; Christou, Evangelos A

    2009-07-01

    gain was high (0.057 +/- 0.03 vs. 0.095 +/- 0.05 N). However, force variability was not affected by the vastly distinct feedback gains at this force, which supported and extended the findings from experiment 1. Our findings demonstrate that although removal of visual feedback amplifies force error, it can reduce force variability during constant isometric contractions due to an altered activation of the primary agonist muscle most likely at moderate force levels in young adults.

  13. [Cerebral hemodynamics in children of 8-12 years old with alterations of the motor activity of central origin].

    PubMed

    Holovchenko, I V; Haĭdaĭ, M I

    2013-01-01

    In children with altered physical activity there is a lack of brain blood supply, which is the most pronounced in the system of the vertebral arteries right hemisphere, and a low volume speed of blood flow in the internal carotid artery and in the system of the vertebral arteries. Children of the main group have a decreased venous outflow from the cavity of the skull, which is accompanied by altered venous circulation in the sinuses of the brain. It is established that in the system of the vertebral arteries a hemispheric asymmetry of growth in the right hemisphere is observed, in contrast to the left hemisphere, indicators of vascular tone of arterial and venous type of small caliber. Children with altered physical activity have higher values of indicators of venous outflow, than the children of the control group, and they have better venous outflow from the carotid system and a slightly worse with vertebro-basilar.

  14. Acute and chronic ethanol exposure differentially alters alcohol dehydrogenase and aldehyde dehydrogenase activity in the zebrafish liver.

    PubMed

    Tran, Steven; Nowicki, Magda; Chatterjee, Diptendu; Gerlai, Robert

    2015-01-01

    Chronic ethanol exposure paradigms have been successfully used in the past to induce behavioral and central nervous system related changes in zebrafish. However, it is currently unknown whether chronic ethanol exposure alters ethanol metabolism in adult zebrafish. In the current study we examine the effect of acute ethanol exposure on adult zebrafish behavioral responses, as well as alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH) activity in the liver. We then examine how two different chronic ethanol exposure paradigms (continuous and repeated ethanol exposure) alter behavioral responses and liver enzyme activity during a subsequent acute ethanol challenge. Acute ethanol exposure increased locomotor activity in a dose-dependent manner. ADH activity was shown to exhibit an inverted U-shaped curve and ALDH activity was decreased by ethanol exposure at all doses. During the acute ethanol challenge, animals that were continuously housed in ethanol exhibited a significantly reduced locomotor response and increased ADH activity, however, ALDH activity did not change. Zebrafish that were repeatedly exposed to ethanol demonstrated a small but significant attenuation of the locomotor response during the acute ethanol challenge but ADH and ALDH activity was similar to controls. Overall, we identified two different chronic ethanol exposure paradigms that differentially alter behavioral and physiological responses in zebrafish. We speculate that these two paradigms may allow dissociation of central nervous system-related and liver enzyme-dependent ethanol induced changes in zebrafish.

  15. Dioxin exposure reduces the steroidogenic capacity of mouse antral follicles mainly at the level of HSD17B1 without altering atresia

    SciTech Connect

    Karman, Bethany N. Basavarajappa, Mallikarjuna S. Hannon, Patrick Flaws, Jodi A.

    2012-10-01

    2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is a potent ovarian toxicant. Previously, we demonstrated that in vitro TCDD (1 nM) exposure decreases production/secretion of the sex steroid hormones progesterone (P4), androstenedione (A4), testosterone (T), and 17β-estradiol (E2) in mouse antral follicles. The purpose of this study was to determine the mechanism by which TCDD inhibits steroidogenesis. Specifically, we examined the effects of TCDD on the steroidogenic enzymes, atresia, and the aryl hydrocarbon receptor (AHR) protein. TCDD exposure for 48 h increased levels of A4, without changing HSD3B1 protein, HSD17B1 protein, estrone (E1), T or E2 levels. Further, TCDD did not alter atresia ratings compared to vehicle at 48 h. TCDD, however, did down regulate the AHR protein at 48 h. TCDD exposure for 96 h decreased transcript levels for Cyp11a1, Cyp17a1, Hsd17b1, and Cyp19a1, but increased Hsd3b1 transcript. TCDD exposure particularly lowered both Hsd17b1 transcript and HSD17B1 protein. However, TCDD exposure did not affect levels of E1 in the media nor atresia ratings at 96 h. TCDD, however, decreased levels of the proapoptotic factor Bax. Collectively, these data suggest that TCDD exposure causes a major block in the steroidogenic enzyme conversion of A4 to T and E1 to E2 and that it regulates apoptotic pathways, favoring survival over death in antral follicles. Finally, the down‐regulation of the AHR protein in TCDD exposed follicles persisted at 96 h, indicating that the activation and proteasomal degradation of this receptor likely plays a central role in the impaired steroidogenic capacity and altered apoptotic pathway of exposed antral follicles. -- Highlights: ► TCDD disrupts steroidogenic enzymes in mouse antral follicles. ► TCDD particularly affects the HSD17B1 enzyme in mouse antral follicles. ► TCDD does not affect atresia ratings in mouse antral follicles. ► TCDD decreases levels of the proapoptitic factor Bax in mouse antral follicles.

  16. Aryl Hydrocarbon Receptor–Mediated Induction of Stearoyl-CoA Desaturase 1 Alters Hepatic Fatty Acid Composition in TCDD-Elicited Steatosis

    PubMed Central

    Angrish, Michelle M.; Jones, A.D.; Harkema, Jack R.; Zacharewski, Timothy R.

    2011-01-01

    2,3,7,8-tetrachlorodibenzo-ρ-dioxin (TCDD) induces hepatic dyslipidemia mediated by the aryl hydrocarbon receptor (AhR). Stearoyl-CoA desaturase 1 (Scd1) performs the rate-limiting step in monounsaturated fatty acid (MUFA) synthesis, desaturating 16:0 and 18:0 into 16:1n7 and 18:1n9, respectively. To further examine the role of Scd1 in TCDD-induced hepatotoxicity, comparative studies were performed in Scd1+/+ and Scd1−/− mice treated with 30 μg/kg TCDD. TCDD induced Scd1 activity, protein, and messenger RNA (mRNA) levels approximately twofold. In Scd1+/+ mice, hepatic effects were marked by increased vacuolization and inflammation and a 3.5-fold increase in serum alanine aminotransferase (ALT) levels. Hepatic triglycerides (TRGs) were induced 3.9-fold and lipid profiling by gas chromatography-mass spectroscopy measured a 1.9-fold increase in fatty acid (FA) levels, consistent with the induction of lipid transport genes. Induction of Scd1 altered FA composition by decreasing saturated fatty acid (SFA) molar ratios 8% and increasing MUFA molar ratios 9%. Furthermore, ChIP-chip analysis revealed AhR enrichment (up to 5.7-fold), and computational analysis identified 16 putative functional dioxin response elements (DREs) within Scd1 genomic loci. Band shift assays confirmed AhR binding with select DREs. In Scd1−/− mice, TCDD induced minimal hepatic vacuolization and inflammation, while serum ALT levels remained unchanged. Although Scd1 deficiency attenuated TCDD-induced TRG accumulation, overall FA levels remained unchanged compared with Scd1+/+ mice. In Scd1−/− mice, TCDD induced SFA ratios 8%, reduced MUFA ratios 13%, and induced polyunsaturated fatty acid ratios 5% relative to treated Scd1+/+ mice. Collectively, these results suggest that AhR regulation of Scd1 not only alters lipid composition but also contributes to the hepatotoxicity of TCDD. PMID:21890736

  17. Ligand-independent activation of the arylhydrocarbon receptor by ETK (Bmx) tyrosine kinase helps MCF10AT1 breast cancer cells to survive in an apoptosis-inducing environment.

    PubMed

    Fujisawa, Yasuko; Li, Wen; Wu, Dalei; Wong, Patrick; Vogel, Christoph; Dong, Bin; Kung, Hsing-Jien; Matsumura, Fumio

    2011-10-01

    It has been reported that the arylhydrocarbon receptor (AHR) is overexpressed in certain types of breast tumors. However, so far no concrete evidence has been provided yet as to why and how the overexpressed AHR in those cancer cells is functionally activated without exogenous ligands. Here we show that the AHR was functionally activated when estrogen receptor-negative, AHR overexpressing MCF10AT1 human breast cancer cells (designated P20E) were subjected to serum starvation. Transfection of cells with ETK-KQ, a plasmid for kinase-dead epithelial and endothelial tyrosine kinase (ETK), attenuated this AHR activation. Artificial over-expression of ETK in P20E cells through transfection with wild-type ETK plasmid (ETK-wt) caused up-regulation of cytochrome P4501a1 (CYP1A1; a marker of functional activation of AHR). Furthermore, ablation of ETK expression by a specific antisense oligonucleotide or AG879, a specific inhibitor of ETK kinase suppressed activation of AHR induced by omeprazole, a strong ligand-independent activator of AHR. Activation of ETK in those cells conferred them resistance to UVB- as well as doxorubicin-induced apoptosis, both of which were reversed by ETK-KQ. Together, these findings support our conclusion that ETK is the tyrosine kinase responsible for the functional activation of the AHR in these mammary epithelial cells. PMID:21861773

  18. Gene-Environment Interactions Target Mitogen-activated Protein 3 Kinase 1 (MAP3K1) Signaling in Eyelid Morphogenesis*

    PubMed Central

    Mongan, Maureen; Meng, Qinghang; Wang, Jingjing; Kao, Winston W.-Y.; Puga, Alvaro; Xia, Ying

    2015-01-01

    Gene-environment interactions determine the biological outcomes through mechanisms that are poorly understood. Mouse embryonic eyelid closure is a well defined model to study the genetic control of developmental programs. Using this model, we investigated how exposure to dioxin-like environmental pollutants modifies the genetic risk of developmental abnormalities. Our studies reveal that mitogen-activated protein 3 kinase 1 (MAP3K1) signaling is a focal point of gene-environment cross-talk. Dioxin exposure, acting through the aryl hydrocarbon receptor (AHR), blocked eyelid closure in genetic mutants in which MAP3K1 signaling was attenuated but did not disturb this developmental program in either wild type or mutant mice with attenuated epidermal growth factor receptor or WNT signaling. Exposure also markedly inhibited c-Jun phosphorylation in Map3k1+/− embryonic eyelid epithelium, suggesting that dioxin-induced AHR pathways can synergize with gene mutations to inhibit MAP3K1 signaling. Our studies uncover a novel mechanism through which the dioxin-AHR axis interacts with the MAP3K1 signaling pathways during fetal development and provide strong empirical evidence that specific gene alterations can increase the risk of developmental abnormalities driven by environmental pollutant exposure. PMID:26109068

  19. Altered cardiovascular autonomic regulation in overweight children engaged in regular physical activity.

    PubMed

    Lucini, Daniela; de Giacomi, Gaia; Tosi, Fabio; Malacarne, Mara; Respizzi, Stefano; Pagani, Massimo

    2013-03-01

    Overweight (OW) and obesity in children are important forerunners of cardiovascular risk, possibly through autonomic nervous system (ANS) dysregulation, while physical exercise exerts a beneficial influence. In this observational study we hypothesise that OW might influence ANS profile even in a population performing high volume of supervised exercise. We study 103 young soccer players, homogeneous in terms of gender (all male), cultural background, school, age (11.2 ± 1 years) and exercise routine, since they all belong to the same soccer club, thus guaranteeing equality of supervised training and similar levels of competitiveness. ANS is evaluated by autoregressive spectral analysis of heart rate and systolic arterial pressure (SAP) variabilities. We estimate also the accumulated weekly Metabolic Equivalents and time spent in sedentary activities. We subdivide the entire population in two subgroups (normal weight and OW) based on the International Obesity Task Force criteria. In OW soccer players (10.7% of total group) we observe an altered profile of autonomic cardiovascular regulation, characterised by higher values of SAP (113 ± 4 vs 100 ± 1 mm Hg, 39.7 ± 3 vs 66.2 ± 10%), higher Low Frequency variability power of SAP (an index of vasomotor sympathetic regulation) (12 ± 3 vs 4.5 mm Hg(2)) and smaller spontaneous baroreflex gain (an index of cardiac vagal regulation) (19 ± 3 vs 33 ± 3 ms/mm Hg) (all (p < 0.02)). Moreover Correlation analysis on the entire study population shows a significant link between anthropometric and autonomic indices. These data show that OW is associated to a clear autonomic impairment even in children subjected to an intense aerobic training. PMID:23086975

  20. Molecular characterization of the aryl hydrocarbon receptor (AhR) pathway in goldfish (Carassius auratus) exposure to TCDD: the mRNA and protein levels.

    PubMed

    Lu, Ming; Chang, Ziwei; Bae, Min-Ji; Oh, Seung Min; Chung, Kyu-Hyuck; Park, Jang-Su

    2013-08-01

    In bony fish or other aquatic vertebrates, the aryl hydrocarbon receptor (AhR) signaling pathway is initiated by exposure to polycyclic (or/and halogenated) aromatic hydrocarbons (PAHs, such as 2,3,7,8-tetrachlorodibenzo-p-dioxin, TCDD), which subsequently induces the up-regulated expression of a series of related genes (such as cytochrome P4501A (CYP1A)). However, a lack of applicable protein reagents hinders our further understanding of the AhR signaling pathway, which focuses only on gene-based investigations. The goldfish (Carassius auratus) is an ideal model for a study of environmental pollution in whole-Asian fresh water. Here, three sensitive and specific polyclonal antisera against goldfish AhR1, AhR2, and CYP1A proteins were developed. These antisera not only bound the in-vitro synthesized target proteins, but recognized the real proteins expressed in goldfish tissues, with minimal cross-reactivity to non-specific proteins. Together with the analysis of semi-quantitative RT-PCR and polyclonal-antibody-based sandwich ELISA, we confirmed that goldfish AhRs differed in the expression (mRNA and protein levels) patterns among test tissues. Importantly, the relative abundance of each AhR mRNA levels from the different tissues showed no obvious consistency with their protein levels. After exposure to TCDD, goldfish AhR2 showed a more sensitivity than AhR1, and stimulated CYP1A expression directly, similar with the other reported fish models. Overall, development of these antibodies in this study will allow valuable and versatile investigations to further understand the AhR signaling pathway, and different expression (mRNA and protein) patterns represent the first step in determining the regulatory mechanisms underlying the TCDD-exposed aquatic environment.

  1. Appraisal frames of pleasant and unpleasant pictures alter emotional responses as reflected in self-report and facial electromyographic activity.

    PubMed

    Wu, Lingdan; Winkler, Markus H; Andreatta, Marta; Hajcak, Greg; Pauli, Paul

    2012-08-01

    Emotional pictures elicit responses across experiential, behavioral and physiological systems. The magnitude of these responses can be modulated by altering one's interpretation of emotional stimuli. Previous studies have indicated that appraisal frames affect subsequent interpretations of upcoming stimuli so as to alter self-reported emotions, ERP activity and autonomic responses. No studies to date have examined the effect of appraisal frames on expressive behaviors as measured by facial EMG. This study aims to test the hypothesis that appraisal frames can alter both emotional experience and facial expression and attempts to examine their effect on the temporal unfolding of facial expressions. Participants (N=20) were exposed to 125 pairs of appraisal frames (neutral or negative/positive) followed by neutral, unpleasant, or pleasant pictures reflecting five conditions: unpleasant-negative, unpleasant-neutral, pleasant-positive, pleasant-neutral and neutral-neutral. Results indicate that the unpleasant-negative compared to the unpleasant-neutral condition led to greater self-reported unpleasantness and arousal, as well as greater corrugator activity, and the pleasant-positive compared to the pleasant-neutral condition led to greater self-reported pleasantness and zygomaticus activity; modulation of facial responses became evident 0.5-1.0s after stimulus onset. These results suggest that appraisal frames effectively alter both emotional experience and facial expressions.

  2. Methoxychlor induces atresia by altering Bcl2 factors and inducing caspase activity in mouse ovarian antral follicles in vitro.

    PubMed

    Basavarajappa, Mallikarjuna S; Karman, Bethany N; Wang, Wei; Gupta, Rupesh K; Flaws, Jodi A

    2012-12-01

    Methoxychlor (MXC) is an organochlorine pesticide widely used in many countries against various species of insects that attack crops and domestic animals. MXC reduces fertility by increasing atresia (death) of antral follicles in vivo. MXC also induces atresia of antral follicles after 96 h in vitro. The current work tested the hypothesis that MXC induces morphological atresia at early time points (24 and 48 h) by altering pro-apoptotic (Bax, Bok, Casp3, and caspase activity) and anti-apoptotic (Bcl2 and Bcl-xL) factors in the follicles. The results indicate that at 24 h, MXC increased Bcl-xL and Bax mRNA levels and increased the ratio of Bax/Bcl2. At 48-96 h, MXC induced morphological atresia. At 24-96 h, MXC increased caspase activities. These data suggest that MXC may induce atresia by altering Bcl2 factors and inducing caspase activities in antral follicles.

  3. Transcriptomes reveal alterations in gravity impact circadian clocks and activate mechanotransduction pathways with adaptation through epigenetic change.

    PubMed

    Casey, Theresa; Patel, Osman V; Plaut, Karen

    2015-04-01

    Few studies have investigated the impact of alterations in gravity on mammalian transcriptomes. Here, we describe the impact of spaceflight on mammary transcriptome of late pregnant rats and the effect of hypergravity exposure on mammary, liver, and adipose transcriptomes in late pregnancy and at the onset of lactation. RNA was isolated from mammary collected on pregnancy day 20 from rats exposed to spaceflight from days 11 to 20 of gestation. To measure the impact of hypergravity on mammary, liver, and adipose transcriptomes we isolated RNA from tissues collected on P20 and lactation day 1 from rats exposed to hypergravity beginning on pregnancy day 9. Gene expression was measured with Affymetrix GeneChips. Microarray analysis of variance revealed alterations in gravity affected the expression of genes that regulate circadian clocks and activate mechanotransduction pathways. Changes in these systems may explain global gene expression changes in immune response, metabolism, and cell proliferation. Expression of genes that modify chromatin structure and methylation was affected, suggesting adaptation to gravity alterations may proceed through epigenetic change. Altered gravity experiments offer insights into the role of forces omnipresent on Earth that shape genomes in heritable ways. Our study is the first to analyze the impact of alterations in gravity on transcriptomes of pregnant and lactating mammals. Findings provide insight into systems that sense gravity and the way in which they affect phenotype, as well as the possibility of sustaining life beyond Earth's orbit. PMID:25649141

  4. Inhibition of urokinase plasminogen activator “uPA” activity alters ethanol consumption and conditioned place preference in mice

    PubMed Central

    Al Maamari, Elyazia; Al Ameri, Mouza; Al Mansouri, Shamma; Bahi, Amine

    2014-01-01

    Urokinase plasminogen activator, uPA, is a serine protease implicated in addiction to drugs of abuse. Using its specific inhibitor, B428, we and others have characterized the role of uPA in the rewarding properties of psychostimulants, including cocaine and amphetamine, but none have examined the role of uPA in ethanol use disorders. Therefore, in the current study, we extended our observations to the role of uPA in ethanol consumption and ethanol-induced conditioned place preference. The general aim of the present series of experiments was to investigate the effects of the administration of the B428 on voluntary alcohol intake and ethanol conditioned reward. A two-bottle choice, unlimited-access paradigm was used to compare ethanol intake between vehicle- and 3, 10, and 30 mg/kg B428-administered mice. For this purpose, the mice were presented with an ethanol solution (2.5%–20%) and water, at each concentration for 4 days, and their consumption was measured daily. Consumption of saccharin and quinine solutions was also measured. Systemic administration of B428 dose-dependently decreased ethanol intake and preference. Additionally, B428 mice did not differ from vehicle mice in their intake of graded solutions of tastants, suggesting that the uPA inhibition did not alter taste function. Also, ethanol metabolism was not affected following B428 injection. More importantly, 1.5 g/kg ethanol-induced conditioned place preference acquisition was blocked following B428 administration. Taken together, our results are the first to implicate uPA inhibition in the regulation of ethanol consumption and preference, and suggest that uPA may be considered as a possible therapeutic drug target for alcoholism and abstinence. PMID:25258509

  5. Activity of NA(+)/H(+) exchangers alters aquaporin-mediated water transport in human placenta.

    PubMed

    Dietrich, Valeria; Damiano, Alicia E

    2015-12-01

    The intracellular pH (pHi) of syncytiotrophoblasts is regulated, in part, by Na(+)/H(+) exchanger (NHE)-1, NHE-2, and NHE-3. Failures in pHi homeostasis could alter critical cellular functions such as water transport and cell volume. Here, we evaluated whether alterations in syncytiotrophoblast pHi could modify water uptake mediated by aquaporins (AQPs) and the contribution of NHEs to this mechanism. We showed that changes in syncytiotrophoblast pHi did not affect water uptake in the presence of functional NHEs. However, inhibition of NHEs alters transcellular water transport mediated by AQPs in acidosis. These results suggest an interaction between placental AQPs and NHEs in the regulation of water uptake during acidotic states.

  6. Exposure to forced swim stress alters local circuit activity and plasticity in the dentate gyrus of the hippocampus.

    PubMed

    Yarom, Orli; Maroun, Mouna; Richter-Levin, Gal

    2008-01-01

    Studies have shown that, depending on its severity and context, stress can affect neural plasticity. Most related studies focused on synaptic plasticity and long-term potentiation (LTP) of principle cells. However, evidence suggests that following high-frequency stimulation, which induces LTP in principal cells, modifications also take place at the level of complex interactions with interneurons within the dentate gyrus, that is, at the local circuit level. So far, the possible effects of stress on local circuit activity and plasticity were not studied. Therefore, we set out to examine the possible alterations in local circuit activity and plasticity following exposure to stress. Local circuit activity and plasticity were measured by using frequency dependant inhibition (FDI) and commissural modulation protocols following exposure to a 15 minute-forced swim trial. Exposure to stress did not alter FDI. The application of theta-burst stimulation (TBS) reduced FDI in both control and stressed rats, but this type of plasticity was greater in stressed rats. Commissural-induced inhibition was significantly higher in stressed rats both before and after applying theta-burst stimulation. These findings indicate that the exposure to acute stress affects aspects of local circuit activity and plasticity in the dentate gyrus. It is possible that these alterations underlie some of the behavioral consequences of the stress experience.

  7. It still hurts: altered endogenous opioid activity in the brain during social rejection and acceptance in major depressive disorder.

    PubMed

    Hsu, D T; Sanford, B J; Meyers, K K; Love, T M; Hazlett, K E; Walker, S J; Mickey, B J; Koeppe, R A; Langenecker, S A; Zubieta, J-K

    2015-02-01

    The μ-opioid receptor (MOR) system, well known for dampening physical pain, is also hypothesized to dampen 'social pain.' We used positron emission tomography scanning with the selective MOR radioligand [(11)C]carfentanil to test the hypothesis that MOR system activation (reflecting endogenous opioid release) in response to social rejection and acceptance is altered in medication-free patients diagnosed with current major depressive disorder (MDD, n=17) compared with healthy controls (HCs, n=18). During rejection, MDD patients showed reduced endogenous opioid release in brain regions regulating stress, mood and motivation, and slower emotional recovery compared with HCs. During acceptance, only HCs showed increased social motivation, which was positively correlated with endogenous opioid release in the nucleus accumbens, a reward structure. Altered endogenous opioid activity in MDD may hinder emotional recovery from negative social interactions and decrease pleasure derived from positive interactions. Both effects may reinforce depression, trigger relapse and contribute to poor treatment outcomes.

  8. Lack of SOD1 gene mutations and activity alterations in two Italian families with amyotrophic lateral sclerosis.

    PubMed

    Gestri, D; Cecchi, C; Tedde, A; Latorraca, S; Orlacchio, A; Grassi, E; Massaro, A M; Liguri, G; St George-Hyslop, P H; Sorbi, S

    2000-08-11

    Amyotrophic lateral sclerosis (ALS) is a progressive fatal disorder, which results from the degeneration of motor neurons in the brain and spinal cord. Approximately 20% of the inherited autosomal dominant cases are due to mutations within the gene coding for Cu/Zn superoxide dismutase 1 (SOD1), a cytosolic homodimeric enzyme that catalyzes the dismutation of toxic superoxide anion. We investigated the presence of SOD1 gene mutations and activity alterations in two unrelated families of ALS patients from Elba, an island of central Italy. No mutation in SOD1 exon 1 to 5 and no activity alteration were observed in all members of the two analyzed ALS families (FALS). These data show an apparent heterogeneous distribution of ALS patients with SOD1 gene mutations among different populations and suggest that another genetic locus could be involved in the disease. PMID:10961653

  9. Differences in activation of aryl hydrocarbon receptors of white sturgeon relative to lake sturgeon are predicted by identities of key amino acids in the ligand binding domain.

    PubMed

    Doering, Jon A; Farmahin, Reza; Wiseman, Steve; Beitel, Shawn C; Kennedy, Sean W; Giesy, John P; Hecker, Markus

    2015-04-01

    Dioxin-like compounds (DLCs) are pollutants of global environmental concern. DLCs elicit their adverse outcomes through activation of the aryl hydrocarbon receptor (AhR). However, there is limited understanding of the mechanisms that result in differences in sensitivity to DLCs among different species of fishes. Understanding these mechanisms is critical for protection of the diversity of fishes exposed to DLCs, including endangered species. This study investigated specific mechanisms that drive responses of two endangered fishes, white sturgeon (Acipenser transmontanus) and lake sturgeon (Acipenser fulvescens) to DLCs. It determined whether differences in sensitivity to activation of AhRs (AhR1 and AhR2) can be predicted based on identities of key amino acids in the ligand binding domain (LBD). White sturgeon were 3- to 30-fold more sensitive than lake sturgeon to exposure to 5 different DLCs based on activation of AhR2. There were no differences in sensitivity between white sturgeon and lake sturgeon based on activation of AhR1. Adverse outcomes as a result of exposure to DLCs have been shown to be mediated through activation of AhR2, but not AhR1, in all fishes studied to date. This indicates that white sturgeon are likely to have greater sensitivity in vivo relative to lake sturgeon. Homology modeling and in silico mutagenesis suggests that differences in sensitivity to activation of AhR2 result from differences in key amino acids at position 388 in the LBD of AhR2 of white sturgeon (Ala-388) and lake sturgeon (Thr-388). This indicates that identities of key amino acids in the LBD of AhR2 could be predictive of both in vitro activation by DLCs and in vivo sensitivity to DLCs in these, and potentially other, fishes.

  10. Induction of mouse UDP-glucuronosyltransferase mRNA expression in liver and intestine by activators of aryl-hydrocarbon receptor, constitutive androstane receptor, pregnane X receptor, peroxisome proliferator-activated receptor alpha, and nuclear factor erythroid 2-related factor 2.

    PubMed

    Buckley, David B; Klaassen, Curtis D

    2009-04-01

    UDP-glucuronosyltransferases (UGTs) catalyze the addition of UDP-glucuronic acid to endo- and xenobiotics, enhancing their water solubility and elimination. Many exogenous compounds, such as microsomal enzyme inducers (MEIs), alter gene expression through xenobiotic-responsive transcription factors, namely, the aryl hydrocarbon receptor (AhR), constitutive androstane receptor (CAR), pregnane X receptor (PXR), peroxisome proliferator-activated receptor alpha (PPARalpha), and nuclear factor erythroid 2-related factor 2 (Nrf2). These transcription factors regulate xenobiotic-inducible expression of hepatic and intestinal biotransformation enzymes and transporters. The purpose of this study was to determine hepatic and intestinal inducibility of mouse Ugt mRNA by MEIs. Male C57BL/6 mice were treated for four consecutive days with activators of AhR [2,3,7,8-tetrachlorodibenzodioxin (TCDD), polychlorinated biphenyl 126, and beta-naphthoflavone], CAR [1,4-bis[2-(3,5-dichloropyridyloxy)]benzene (TCPOBOP), phenobarbital, and diallyl sulfide], PXR [pregnenolone-16alpha-carbonitrile (PCN), spironolactone, and dexamethasone], PPARalpha (clofibrate, ciprofibrate, and diethylhexylphthalate), and Nrf2 (oltipraz, ethoxyquin, and butylated hydroxyanisole), respectively. Ugt1a1 mRNA expression in liver was induced by activators of all five transcription factor pathways, Ugt1a5 by Nrf2 activators, Ugt1a6 by all the pathways except CAR, and Ugt1a9 by all the pathways except Nrf2. Ugt2b35 mRNA in liver was induced by AhR activators and Ugt2b36 by CAR and PPARalpha activators. Throughout the small and large intestine, the AhR ligand TCDD increased Ugt1a6 and Ugt1a7 mRNA. In small intestine, the PXR activator PCN increased Ugt1a1, Ugt1a6, Ugt1a7, Ugt2b34, and Ugt2b35 mRNA in the duodenum. In conclusion, chemical activation of AhR, CAR, PXR, PPARalpha, and Nrf2 in mouse results in induction of distinct Ugt gene sets in liver and intestine, predominantly the Ugt1a isoforms.

  11. Arsenic alters vascular smooth muscle cell focal adhesion complexes leading to activation of FAK-src mediated pathways

    SciTech Connect

    Pysher, Michele D. Chen, Qin M.; Vaillancourt, Richard R.

    2008-09-01

    Chronic exposure to arsenic has been linked to tumorigenesis, cardiovascular disease, hypertension, atherosclerosis, and peripheral vascular disease; however, the molecular mechanisms underlying its pathological effects remain elusive. In this study, we investigated arsenic-induced alteration of focal adhesion protein complexes in normal, primary vascular smooth muscle cells. We demonstrate that exposure to environmentally relevant concentrations of arsenic (50 ppb As{sup 3+}) can alter focal adhesion protein co-association leading to activation of downstream pathways. Co-associated proteins were identified and quantitated via co-immunoprecipitation, SDS-PAGE, and Western blot analysis followed by scanning densitometry. Activation of MAPK pathways in total cell lysates was evaluated using phosphor-specific antibodies. In our model, arsenic treatment caused a sustained increase in FAK-src association and activation, and induced the formation of unique signaling complexes (beginning after 3-hour As{sup 3+} exposure and continuing throughout the 12-hour time course studied). The effects of these alterations were manifested as chronic stimulation of downstream PAK, ERK and JNK pathways. Past studies have demonstrated that these pathways are involved in cellular survival, growth, proliferation, and migration in VSMCs.

  12. Erythrocyte membrane changes of chorea-acanthocytosis are the result of altered Lyn kinase activity.

    PubMed

    De Franceschi, Lucia; Tomelleri, Carlo; Matte, Alessandro; Brunati, Anna Maria; Bovee-Geurts, Petra H; Bertoldi, Mariarita; Lasonder, Edwin; Tibaldi, Elena; Danek, Adrian; Walker, Ruth H; Jung, Hans H; Bader, Benedikt; Siciliano, Angela; Ferru, Emanuela; Mohandas, Narla; Bosman, Giel J C G M

    2011-11-17

    Acanthocytic RBCs are a peculiar diagnostic feature of chorea-acanthocytosis (ChAc), a rare autosomal recessive neurodegenerative disorder. Although recent years have witnessed some progress in the molecular characterization of ChAc, the mechanism(s) responsible for generation of acanthocytes in ChAc is largely unknown. As the membrane protein composition of ChAc RBCs is similar to that of normal RBCs, we evaluated the tyrosine (Tyr)-phosphorylation profile of RBCs using comparative proteomics. Increased Tyr phosphorylation state of several membrane proteins, including band 3, β-spectrin, and adducin, was noted in ChAc RBCs. In particular, band 3 was highly phosphorylated on the Tyr-904 residue, a functional target of Lyn, but not on Tyr-8, a functional target of Syk. In ChAc RBCs, band 3 Tyr phosphorylation by Lyn was independent of the canonical Syk-mediated pathway. The ChAc-associated alterations in RBC membrane protein organization appear to be the result of increased Tyr phosphorylation leading to altered linkage of band 3 to the junctional complexes involved in anchoring the membrane to the cytoskeleton as supported by coimmunoprecipitation of β-adducin with band 3 only in ChAc RBC-membrane treated with the Lyn-inhibitor PP2. We propose this altered association between membrane skeleton and membrane proteins as novel mechanism in the generation of acanthocytes in ChAc.

  13. Central Muscarinic Cholinergic Activation Alters Interaction between Splenic Dendritic Cell and CD4+CD25- T Cells in Experimental Colitis

    PubMed Central

    Pavlov, Valentin A.; Tracey, Kevin J.; Khafipour, Ehsan; Ghia, Jean-Eric

    2014-01-01

    Background The cholinergic anti-inflammatory pathway (CAP) is based on vagus nerve (VN) activity that regulates macrophage and dendritic cell responses in the spleen through alpha-7 nicotinic acetylcholine receptor (a7nAChR) signaling. Inflammatory bowel disease (IBD) patients present dysautonomia with decreased vagus nerve activity, dendritic cell and T cell over-activation. The aim of this study was to investigate whether central activation of the CAP alters the function of dendritic cells (DCs) and sequential CD4+/CD25−T cell activation in the context of experimental colitis. Methods The dinitrobenzene sulfonic acid model of experimental colitis in C57BL/6 mice was used. Central, intracerebroventricular infusion of the M1 muscarinic acetylcholine receptor agonist McN-A-343 was used to activate CAP and vagus nerve and/or splenic nerve transection were performed. In addition, the role of α7nAChR signaling and the NF-kB pathway was studied. Serum amyloid protein (SAP)-A, colonic tissue cytokines, IL-12p70 and IL-23 in isolated splenic DCs, and cytokines levels in DC-CD4+CD25−T cell co-culture were determined. Results McN-A-343 treatment reduced colonic inflammation associated with decreased pro-inflammatory Th1/Th17 colonic and splenic cytokine secretion. Splenic DCs cytokine release was modulated through α7nAChR and the NF-kB signaling pathways. Cholinergic activation resulted in decreased CD4+CD25−T cell priming. The anti-inflammatory efficacy of central cholinergic activation was abolished in mice with vagotomy or splenic neurectomy. Conclusions Suppression of splenic immune cell activation and altered interaction between DCs and T cells are important aspects of the beneficial effect of brain activation of the CAP in experimental colitis. These findings may lead to improved therapeutic strategies in the treatment of IBD. PMID:25295619

  14. Furosemide fails to alter plasma active or inactive renin in conscious sheep but does so in anaesthetized animals.

    PubMed Central

    Lush, D J; Munday, K A; Noble, A R

    1983-01-01

    Regulation of plasma levels of active and inactive renin was investigated using sheep with indwelling artery, vein and bladder catheters. Control and experimental studies were carried out in the same animals on different days. Volume depletion during any single experiment was limited to a maximum of 50 ml. Despite large changes in sodium and water excretion, the diuretic furosemide at two dose levels, 1 and 10 mg/kg, failed to alter plasma levels of either active or inactive renin in conscious sheep. Induction of pentobarbitone anaesthesia in the sheep did not, per se, alter either plasma active or inactive renin. Furosemide (10 mg/kg) in anaesthetized animals produced a similar diuresis and natriuresis response to conscious sheep, but plasma active renin increased by 270% and inactive renin decreased to zero. In conscious sheep given an infusion of papaverine, furosemide also produced an increase in plasma active renin and a concurrent decrease in the inactive form. In both anaesthetized animals and in conscious sheep infused with papaverine, furosemide-induced intrarenal vasodilation, as evidenced by changes in clearance of p-aminohippuric acid, was much reduced in comparison to the conscious animals. This may be significant in relation to the control of renin secretion. It appears that the macula densa sodium receptor, which is considered to regulate renin release, will only function after it has been primed by other intra- or extrarenal factors. This is discussed, particularly in relation to the possible role played by the prostaglandin system. PMID:6350561

  15. Decreased glutathione S-transferase expression and activity and altered sex steroids in Lake Apopka brown bullheads (Ameriurus nebulosus)

    USGS Publications Warehouse

    Gallagher, E.P.; Gross, T.S.; Sheehy, K.M.

    2001-01-01

    A number of freshwater lakes and reclaimed agricultural sites in Central Florida have been the receiving waters for agrochemical and municipal runoff. One of these sites, Lake Apopka, is also a eutrophic system that has been the focus of several case studies reporting altered reproductive activity linked to bioaccumulation of persistent organochlorine chemicals in aquatic species. The present study was initiated to determine if brown bullheads (Ameriurus nebulosus) from the north marsh of Lake Apopka (Lake Apopka Marsh) exhibit an altered capacity to detoxify environmental chemicals through hepatic glutathione S-transferase (GST)-mediated conjugation as compared with bullheads from a nearby reference site (Lake Woodruff). We also compared plasma sex hormone concentrations (testosterone, 17-?? estradiol, and 11 keto-testosterone) in bullheads from the two sites. Female bullheads from Lake Apopka had 40% lower initial rate GST conjugative activity toward 1-chloro-2,4-dinitrobenzene (CDNB), 50% lower activity towards p-nitrobutyl chloride (NBC), 33% lower activity toward ethacrynic acid (ECA), and 43% lower activity toward ??5-androstene-3,17-dione (??5-ADI), as compared with female bullheads from Lake Woodruff. Enzyme kinetic analyses demonstrated that female bullheads from Lake Apopka had lower GST-catalyzed CDNB clearance than did female Lake Woodruff bullheads. Western blotting studies of bullhead liver cytosolic proteins demonstrated that the reduced GST catalytic activities in female Lake Apopka bullheads were accompanied by lower expression of hepatic GST protein. No site differences were observed with respect to GST activities or GST protein expression in male bullheads. Female Lake Apopka bullheads also had elevated concentrations of plasma androgens (testosterone and 11-ketotestosterone) as compared with females from Lake Woodruff. In contrast, male Lake Apopka bullheads had elevated levels of plasma estrogen but similar levels of androgens as compared with

  16. Phenotype refinement strengthens the association of AHR and CYP1A1 genotype with caffeine consumption.

    PubMed

    McMahon, George; Taylor, Amy E; Davey Smith, George; Munafò, Marcus R

    2014-01-01

    Two genetic loci, one in the cytochrome P450 1A1 (CYP1A1) and 1A2 (CYP1A2) gene region (rs2472297) and one near the aryl-hydrocarbon receptor (AHR) gene (rs6968865), have been associated with habitual caffeine consumption. We sought to establish whether a more refined and comprehensive assessment of caffeine consumption would provide stronger evidence of association, and whether a combined allelic score comprising these two variants would further strengthen the association. We used data from between 4,460 and 7,520 women in the Avon Longitudinal Study of Parents and Children, a longitudinal birth cohort based in the United Kingdom. Self-report data on coffee, tea and cola consumption (including consumption of decaffeinated drinks) were available at multiple time points. Both genotypes were individually associated with total caffeine consumption, and with coffee and tea consumption. There was no association with cola consumption, possibly due to low levels of consumption in this sample. There was also no association with measures of decaffeinated drink consumption, indicating that the observed association is most likely mediated via caffeine. The association was strengthened when a combined allelic score was used, accounting for up to 1.28% of phenotypic variance. This was not associated with potential confounders of observational association. A combined allelic score accounts for sufficient phenotypic variance in caffeine consumption that this may be useful in Mendelian randomization studies. Future studies may therefore be able to use this combined allelic score to explore causal effects of habitual caffeine consumption on health outcomes. PMID:25075865

  17. Phenotype Refinement Strengthens the Association of AHR and CYP1A1 Genotype with Caffeine Consumption

    PubMed Central

    McMahon, George; Taylor, Amy E.; Davey Smith, George; Munafò, Marcus R.

    2014-01-01

    Two genetic loci, one in the cytochrome P450 1A1 (CYP1A1) and 1A2 (CYP1A2) gene region (rs2472297) and one near the aryl-hydrocarbon receptor (AHR) gene (rs6968865), have been associated with habitual caffeine consumption. We sought to establish whether a more refined and comprehensive assessment of caffeine consumption would provide stronger evidence of association, and whether a combined allelic score comprising these two variants would further strengthen the association. We used data from between 4,460 and 7,520 women in the Avon Longitudinal Study of Parents and Children, a longitudinal birth cohort based in the United Kingdom. Self-report data on coffee, tea and cola consumption (including consumption of decaffeinated drinks) were available at multiple time points. Both genotypes were individually associated with total caffeine consumption, and with coffee and tea consumption. There was no association with cola consumption, possibly due to low levels of consumption in this sample. There was also no association with measures of decaffeinated drink consumption, indicating that the observed association is most likely mediated via caffeine. The association was strengthened when a combined allelic score was used, accounting for up to 1.28% of phenotypic variance. This was not associated with potential confounders of observational association. A combined allelic score accounts for sufficient phenotypic variance in caffeine consumption that this may be useful in Mendelian randomization studies. Future studies may therefore be able to use this combined allelic score to explore causal effects of habitual caffeine consumption on health outcomes. PMID:25075865

  18. In Absence of the Cellular Prion Protein, Alterations in Copper Metabolism and Copper-Dependent Oxidase Activity Affect Iron Distribution

    PubMed Central

    Gasperini, Lisa; Meneghetti, Elisa; Legname, Giuseppe; Benetti, Federico

    2016-01-01

    Essential elements as copper and iron modulate a wide range of physiological functions. Their metabolism is strictly regulated by cellular pathways, since dysregulation of metal homeostasis is responsible for many detrimental effects. Neurodegenerative disorders such as Alzheimer's disease, Parkinson's disease and prion diseases are characterized by alterations of metal ions. These neurodegenerative maladies involve proteins that bind metals and mediate their metabolism through not well-defined mechanisms. Prion protein, for instance, interacts with divalent cations via multiple metal-binding sites and it modulates several metal-dependent physiological functions, such as S-nitrosylation of NMDA receptors. In this work we focused on the effect of prion protein absence on copper and iron metabolism during development and adulthood. In particular, we investigated copper and iron functional values in serum and several organs such as liver, spleen, total brain and isolated hippocampus. Our results show that iron content is diminished in prion protein-null mouse serum, while it accumulates in liver and spleen. Our data suggest that these alterations can be due to impairments in copper-dependent cerulopalsmin activity which is known to affect iron mobilization. In prion protein-null mouse total brain and hippocampus, metal ion content shows a fluctuating trend, suggesting the presence of homeostatic compensatory mechanisms. However, copper and iron functional values are likely altered also in these two organs, as indicated by the modulation of metal-binding protein expression levels. Altogether, these results reveal that the absence of the cellular prion protein impairs copper metabolism and copper-dependent oxidase activity, with ensuing alteration of iron mobilization from cellular storage compartments. PMID:27729845

  19. Maternal diet-induced obesity alters mitochondrial activity and redox status in mouse oocytes and zygotes.

    PubMed

    Igosheva, Natalia; Abramov, Andrey Y; Poston, Lucilla; Eckert, Judith J; Fleming, Tom P; Duchen, Michael R; McConnell, Josie

    2010-01-01

    The negative impact of obesity on reproductive success is well documented but the stages at which development of the conceptus is compromised and the mechanisms responsible for the developmental failure still remain unclear. Recent findings suggest that mitochondria may be a contributing factor. However to date no studies have directly addressed the consequences of maternal obesity on mitochondria in early embryogenesis.Using an established murine model of maternal diet induced obesity and a live cell dynamic fluorescence imaging techniques coupled with molecular biology we have investigated the underlying mechanisms of obesity-induced reduced fertility. Our study is the first to show that maternal obesity prior to conception is associated with altered mitochondria in mouse oocytes and zygotes. Specifically, maternal diet-induced obesity in mice led to an increase in mitochondrial potential, mitochondrial DNA content and biogenesis. Generation of reactive oxygen species (ROS) was raised while glutathione was depleted and the redox state became more oxidised, suggestive of oxidative stress. These altered mitochondrial properties were associated with significant developmental impairment as shown by the increased number of obese mothers who failed to support blastocyst formation compared to lean dams. We propose that compromised oocyte and early embryo mitochondrial metabolism, resulting from excessive nutrient exposure prior to and during conception, may underlie poor reproductive outcomes frequently reported in obese women.

  20. Benzotriazole UV-stabilizers and benzotriazole: Antiandrogenic activity in vitro and activation of aryl hydrocarbon receptor pathway in zebrafish eleuthero-embryos.

    PubMed

    Fent, Karl; Chew, Geraldine; Li, Jun; Gomez, Elena

    2014-06-01

    Benzotriazole UV-stabilizers (BUVs) are applied in materials for protection against UV-irradiation. They are widely used, bioaccumulate and share structural similarities to benzotriazole. Benzotriazole (1HBT) finds application as corrosion inhibitor in dishwashing detergents, antifreeze (vehicles) and aircraft de-icing agent. BUVs and 1HBT are persistent and ubiquitous in the aquatic environment, but there is little understanding of the ecotoxicological implications. Here, we comparatively analyze the hormonal activity in vitro and effects in zebrafish eleuthero-embryos in vivo. 2-(2-Hydroxy-5-methylphenyl)benzotriazole (UV-P), 2-(3-t-butyl-2-hydroxy-5-methylphenyl)-5-chlorobenzotriazole (UV-326), UV-327, UV-328, UV-329 and UV-320 showed no estrogenicity (YES assay) and androgenicity (YAS assay). However, UV-P and 1HBT showed significant antiandrogenic activity. We assessed the transcription profiles of up to 26 genes associated with different toxicological pathways in zebrafish eleuthero-embryos to elucidate potential modes of action of UV-P, UV-326 and 1HBT. Embryos were experimentally exposed for 144hpf to three measured concentrations of 15.8, 70.8, and 690μg/L UV-P, 7.5, 31.7, and 84.3μg/L UV-326 and 7.9, 97.3 and 1197.3μg/L 1HBT. Among the 26 transcripts, the induction of the aryl hydrocarbon receptor (AHR) pathway by UV-P and UV-326 was the most significant finding. UV-P led to dose-related induction of AHR1, ARNT2 and cyp1a1, as well as of phase II enzymes glutathione-S-transferase (gstp1) and ugt1a. UV-326 led to a significant induction of cyp1a1 and AHR2, but down-regulation of gstp1 at 84μg/L. Only little transcriptional alterations occurred in genes related to apoptosis, oxidative stress, hormone receptors, and steroidogenesis including aromatase. 1HBT led to only a few expressional changes at 1197μg/L. Our data lead to the conclusion that UV-P and UV-326 activate the AHR-pathway, whereas 1HBT shows only little transcriptional alterations. It

  1. In Utero Cigarette Smoke Affects Allergic Airway Disease But Does Not Alter the Lung Methylome.

    PubMed

    Eyring, Kenneth R; Pedersen, Brent S; Yang, Ivana V; Schwartz, David A

    2015-01-01

    Prenatal and postnatal cigarette smoke exposure enhances the risk of developing asthma. Despite this as well as other smoking related risks, 11% of women still smoke during pregnancy. We hypothesized that cigarette smoke exposure during prenatal development generates long lasting differential methylation altering transcriptional activity that correlates with disease. In a house dust mite (HDM) model of allergic airway disease, we measured airway hyperresponsiveness (AHR) and airway inflammation between mice exposed prenatally to cigarette smoke (CS) or filtered air (FA). DNA methylation and gene expression were then measured in lung tissue. We demonstrate that HDM-treated CS mice develop a more severe allergic airway disease compared to HDM-treated FA mice including increased AHR and airway inflammation. While DNA methylation changes between the two HDM-treated groups failed to reach genome-wide significance, 99 DMRs had an uncorrected p-value < 0.001. 6 of these 99 DMRs were selected for validation, based on the immune function of adjacent genes, and only 2 of the 6 DMRs confirmed the bisulfite sequencing data. Additionally, genes near these 6 DMRs (Lif, Il27ra, Tle4, Ptk7, Nfatc2, and Runx3) are differentially expressed between HDM-treated CS mice and HDM-treated FA mice. Our findings confirm that prenatal exposure to cigarette smoke is sufficient to modify allergic airway disease; however, it is unlikely that specific methylation changes account for the exposure-response relationship. These findings highlight the important role in utero cigarette smoke exposure plays in the development of allergic airway disease. PMID:26642056

  2. Activation of aryl hydrocarbon receptor signaling by extracts of teak and other wood dusts.

    PubMed

    Wilson, Mark J; Sabbioni, Gabriele; Rando, Roy; Miller, Charles A

    2015-12-01

    Wood dusts, as a group, are categorized as known human carcinogens, but the risks of exposure to specific types of wood dusts and the carcinogenic chemicals they contain are not well studied. Aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor that is linked to the carcinogenic action of specific classes of chemicals. Here we examined whether chemicals in various wood dusts had the potential to activate AhR signaling as a potential toxic mechanism of action. We found that methanol extracts of teak, walnut, mahogany, and poplar dusts contained a wide range of AhR ligand activity, whereas extracts of oak, pine, and other softwoods did not contain appreciable activity. Teak dust extract, being particularly potent, was subjected to chemical analysis. The 2-methylanthraquinone (2-MAQ) accounted for the AhR ligand activity and was present at an average concentration of 0.27 parts per hundred in teak dust. Pure 2-MAQ potently induced AhR signaling (EC50 115 nM), confirming that this was the active ligand. Aqueous extracts of teak dust made using yeast or mammalian cell culture medium also contained robust AhR activity, suggesting the 2-MAQ ligand is soluble at bioactive concentrations in physiologically relevant fluids. The high concentration and potency of 2-MAQ in teak wood suggest it may mediate toxic effects through activation of AhR signaling in exposed wood workers.

  3. Food reward without a timing component does not alter the timing of activity under positive energy balance.

    PubMed

    van der Vinne, V; Akkerman, J; Lanting, G D; Riede, S J; Hut, R A

    2015-09-24

    Circadian clocks drive daily rhythms in physiology and behavior which allow organisms to anticipate predictable daily changes in the environment. In most mammals, circadian rhythms result in nocturnal activity patterns although plasticity of the circadian system allows activity patterns to shift to different times of day. Such plasticity is seen when food access is restricted to a few hours during the resting (light) phase resulting in food anticipatory activity (FAA) in the hours preceding food availability. The mechanisms underlying FAA are unknown but data suggest the involvement of the reward system and homeostatic regulation of metabolism. We previously demonstrated the isolated effect of metabolism by inducing diurnality in response to energetic challenges. Here the importance of reward timing in inducing daytime activity is assessed. The daily activity distribution of mice earning palatable chocolate at their preferred time by working in a running wheel was compared with that of mice receiving a timed palatable meal at noon. Mice working for chocolate (WFC) without being energetically challenged increased their total daily activity but this did not result in a shift to diurnality. Providing a chocolate meal at noon each day increased daytime activity, identifying food timing as a factor capable of altering the daily distribution of activity and rest. These results show that timing of food reward and energetic challenges are both independently sufficient to induce diurnality in nocturnal mammals. FAA observed following timed food restriction is likely the result of an additive effect of distinct regulatory pathways activated by energetic challenges and food reward.

  4. Food reward without a timing component does not alter the timing of activity under positive energy balance.

    PubMed

    van der Vinne, V; Akkerman, J; Lanting, G D; Riede, S J; Hut, R A

    2015-09-24

    Circadian clocks drive daily rhythms in physiology and behavior which allow organisms to anticipate predictable daily changes in the environment. In most mammals, circadian rhythms result in nocturnal activity patterns although plasticity of the circadian system allows activity patterns to shift to different times of day. Such plasticity is seen when food access is restricted to a few hours during the resting (light) phase resulting in food anticipatory activity (FAA) in the hours preceding food availability. The mechanisms underlying FAA are unknown but data suggest the involvement of the reward system and homeostatic regulation of metabolism. We previously demonstrated the isolated effect of metabolism by inducing diurnality in response to energetic challenges. Here the importance of reward timing in inducing daytime activity is assessed. The daily activity distribution of mice earning palatable chocolate at their preferred time by working in a running wheel was compared with that of mice receiving a timed palatable meal at noon. Mice working for chocolate (WFC) without being energetically challenged increased their total daily activity but this did not result in a shift to diurnality. Providing a chocolate meal at noon each day increased daytime activity, identifying food timing as a factor capable of altering the daily distribution of activity and rest. These results show that timing of food reward and energetic challenges are both independently sufficient to induce diurnality in nocturnal mammals. FAA observed following timed food restriction is likely the result of an additive effect of distinct regulatory pathways activated by energetic challenges and food reward. PMID:26215921

  5. Altered Hub Functioning and Compensatory Activations in the Connectome: A Meta-Analysis of Functional Neuroimaging Studies in Schizophrenia

    PubMed Central

    Crossley, Nicolas A.; Mechelli, Andrea; Ginestet, Cedric; Rubinov, Mikail; Bullmore, Edward T.; McGuire, Philip

    2016-01-01

    Background: Functional neuroimaging studies of schizophrenia have identified abnormal activations in many brain regions. In an effort to interpret these findings from a network perspective, we carried out a meta-analysis of this literature, mapping anatomical locations of under- and over-activation to the topology of a normative human functional connectome. Methods: We included 314 task-based functional neuroimaging studies including more than 5000 patients with schizophrenia and over 5000 controls. Coordinates of significant under- or over-activations in patients relative to controls were mapped to nodes of a normative connectome defined by a prior meta-analysis of 1641 functional neuroimaging studies of task-related activation in healthy volunteers. Results: Under-activations and over-activations were reported in a wide diversity of brain regions. Both under- and over-activations were significantly more likely to be located in hub nodes that constitute the “rich club” or core of the normative connectome. In a subset of 121 studies that reported both under- and over-activations in the same patients, we found that, in network terms, these abnormalities were located in close topological proximity to each other. Under-activation in a peripheral node was more frequently associated specifically with over-activation of core nodes than with over-activation of another peripheral node. Conclusions: Although schizophrenia is associated with altered brain functional activation in a wide variety of regions, abnormal responses are concentrated in hubs of the normative connectome. Task-specific under-activation in schizophrenia is accompanied by over-activation of topologically central, less functionally specialized network nodes, which may represent a compensatory response. PMID:26472684

  6. Supplemental Feeding for Ecotourism Reverses Diel Activity and Alters Movement Patterns and Spatial Distribution of the Southern Stingray, Dasyatis americana

    PubMed Central

    Corcoran, Mark J.; Wetherbee, Bradley M.; Shivji, Mahmood S.; Potenski, Matthew D.; Chapman, Demian D.; Harvey, Guy M.

    2013-01-01

    Southern stingrays, Dasyatis americana, have been provided supplemental food in ecotourism operations at Stingray City Sandbar (SCS), Grand Cayman since 1986, with this site becoming one of the world’s most famous and heavily visited marine wildlife interaction venues. Given expansion of marine wildlife interactive tourism worldwide, there are questions about the effects of such activities on the focal species and their ecosystems. We used a combination of acoustic telemetry and tag-recapture efforts to test the hypothesis that human-sourced supplemental feeding has altered stingray activity patterns and habitat use at SCS relative to wild animals at control sites. Secondarily, we also qualitatively estimated the population size of stingrays supporting this major ecotourism venue. Tag-recapture data indicated that a population of at least 164 stingrays, over 80% female, utilized the small area at SCS for prolonged periods of time. Examination of comparative movements of mature female stingrays at SCS and control sites revealed strong differences between the two groups: The fed animals demonstrated a notable inversion of diel activity, being constantly active during the day with little movement at night compared to the nocturnally active wild stingrays; The fed stingrays utilized significantly (p<0.05) smaller 24 hour activity spaces compared to wild conspecifics, staying in close proximity to the ecotourism site; Fed stingrays showed a high degree of overlap in their core activity spaces compared to wild stingrays which were largely solitary in the spaces utilized (72% vs. 3% overlap respectively). Supplemental feeding has strikingly altered movement behavior and spatial distribution of the stingrays, and generated an atypically high density of animals at SCS which could have downstream fitness costs for individuals and potentially broader ecosystem effects. These findings should help environmental managers plan mitigating measures for existing operations, and

  7. Supramammillary serotonin reduction alters place learning and concomitant hippocampal, septal, and supramammillar theta activity in a Morris water maze.

    PubMed

    Hernández-Pérez, J Jesús; Gutiérrez-Guzmán, Blanca E; López-Vázquez, Miguel Á; Olvera-Cortés, María E

    2015-01-01

    Hippocampal theta activity is related to spatial information processing, and high-frequency theta activity, in particular, has been linked to efficient spatial memory performance. Theta activity is regulated by the synchronizing ascending system (SAS), which includes mesencephalic and diencephalic relays. The supramamillary nucleus (SUMn) is located between the reticularis pontis oralis and the medial septum (MS), in close relation with the posterior hypothalamic nucleus (PHn), all of which are part of this ascending system. It has been proposed that the SUMn plays a role in the modulation of hippocampal theta-frequency; this could occur through direct connections between the SUMn and the hippocampus or through the influence of the SUMn on the MS. Serotonergic raphe neurons prominently innervate the hippocampus and several components of the SAS, including the SUMn. Serotonin desynchronizes hippocampal theta activity, and it has been proposed that serotonin may regulate learning through the modulation of hippocampal synchrony. In agreement with this hypothesis, serotonin depletion in the SUMn/PHn results in deficient spatial learning and alterations in CA1 theta activity-related learning in a Morris water maze. Because it has been reported that SUMn inactivation with lidocaine impairs the consolidation of reference memory, we asked whether changes in hippocampal theta activity related to learning would occur through serotonin depletion in the SUMn, together with deficiencies in memory. We infused 5,7-DHT bilaterally into the SUMn in rats and evaluated place learning in the standard Morris water maze task. Hippocampal (CA1 and dentate gyrus), septal and SUMn EEG were recorded during training of the test. The EEG power in each region and the coherence between the different regions were evaluated. Serotonin depletion in the SUMn induced deficient spatial learning and altered the expression of hippocampal high-frequency theta activity. These results provide evidence in

  8. Supramammillary serotonin reduction alters place learning and concomitant hippocampal, septal, and supramammillar theta activity in a Morris water maze

    PubMed Central

    Hernández-Pérez, J. Jesús; Gutiérrez-Guzmán, Blanca E.; López-Vázquez, Miguel Á.; Olvera-Cortés, María E.

    2015-01-01

    Hippocampal theta activity is related to spatial information processing, and high-frequency theta activity, in particular, has been linked to efficient spatial memory performance. Theta activity is regulated by the synchronizing ascending system (SAS), which includes mesencephalic and diencephalic relays. The supramamillary nucleus (SUMn) is located between the reticularis pontis oralis and the medial septum (MS), in close relation with the posterior hypothalamic nucleus (PHn), all of which are part of this ascending system. It has been proposed that the SUMn plays a role in the modulation of hippocampal theta-frequency; this could occur through direct connections between the SUMn and the hippocampus or through the influence of the SUMn on the MS. Serotonergic raphe neurons prominently innervate the hippocampus and several components of the SAS, including the SUMn. Serotonin desynchronizes hippocampal theta activity, and it has been proposed that serotonin may regulate learning through the modulation of hippocampal synchrony. In agreement with this hypothesis, serotonin depletion in the SUMn/PHn results in deficient spatial learning and alterations in CA1 theta activity-related learning in a Morris water maze. Because it has been reported that SUMn inactivation with lidocaine impairs the consolidation of reference memory, we asked whether changes in hippocampal theta activity related to learning would occur through serotonin depletion in the SUMn, together with deficiencies in memory. We infused 5,7-DHT bilaterally into the SUMn in rats and evaluated place learning in the standard Morris water maze task. Hippocampal (CA1 and dentate gyrus), septal and SUMn EEG were recorded during training of the test. The EEG power in each region and the coherence between the different regions were evaluated. Serotonin depletion in the SUMn induced deficient spatial learning and altered the expression of hippocampal high-frequency theta activity. These results provide evidence in

  9. Supplemental feeding for ecotourism reverses diel activity and alters movement patterns and spatial distribution of the southern stingray, Dasyatis americana.

    PubMed

    Corcoran, Mark J; Wetherbee, Bradley M; Shivji, Mahmood S; Potenski, Matthew D; Chapman, Demian D; Harvey, Guy M

    2013-01-01

    Southern stingrays, Dasyatis americana, have been provided supplemental food in ecotourism operations at Stingray City Sandbar (SCS), Grand Cayman since 1986, with this site becoming one of the world's most famous and heavily visited marine wildlife interaction venues. Given expansion of marine wildlife interactive tourism worldwide, there are questions about the effects of such activities on the focal species and their ecosystems. We used a combination of acoustic telemetry and tag-recapture efforts to test the hypothesis that human-sourced supplemental feeding has altered stingray activity patterns and habitat use at SCS relative to wild animals at control sites. Secondarily, we also qualitatively estimated the population size of stingrays supporting this major ecotourism venue. Tag-recapture data indicated that a population of at least 164 stingrays, over 80% female, utilized the small area at SCS for prolonged periods of time. Examination of comparative movements of mature female stingrays at SCS and control sites revealed strong differences between the two groups: The fed animals demonstrated a notable inversion of diel activity, being constantly active during the day with little movement at night compared to the nocturnally active wild stingrays; The fed stingrays utilized significantly (p<0.05) smaller 24 hour activity spaces compared to wild conspecifics, staying in close proximity to the ecotourism site; Fed stingrays showed a high degree of overlap in their core activity spaces compared to wild stingrays which were largely solitary in the spaces utilized (72% vs. 3% overlap respectively). Supplemental feeding has strikingly altered movement behavior and spatial distribution of the stingrays, and generated an atypically high density of animals at SCS which could have downstream fitness costs for individuals and potentially broader ecosystem effects. These findings should help environmental managers plan mitigating measures for existing operations, and

  10. Supplemental feeding for ecotourism reverses diel activity and alters movement patterns and spatial distribution of the southern stingray, Dasyatis americana.

    PubMed

    Corcoran, Mark J; Wetherbee, Bradley M; Shivji, Mahmood S; Potenski, Matthew D; Chapman, Demian D; Harvey, Guy M

    2013-01-01

    Southern stingrays, Dasyatis americana, have been provided supplemental food in ecotourism operations at Stingray City Sandbar (SCS), Grand Cayman since 1986, with this site becoming one of the world's most famous and heavily visited marine wildlife interaction venues. Given expansion of marine wildlife interactive tourism worldwide, there are questions about the effects of such activities on the focal species and their ecosystems. We used a combination of acoustic telemetry and tag-recapture efforts to test the hypothesis that human-sourced supplemental feeding has altered stingray activity patterns and habitat use at SCS relative to wild animals at control sites. Secondarily, we also qualitatively estimated the population size of stingrays supporting this major ecotourism venue. Tag-recapture data indicated that a population of at least 164 stingrays, over 80% female, utilized the small area at SCS for prolonged periods of time. Examination of comparative movements of mature female stingrays at SCS and control sites revealed strong differences between the two groups: The fed animals demonstrated a notable inversion of diel activity, being constantly active during the day with little movement at night compared to the nocturnally active wild stingrays; The fed stingrays utilized significantly (p<0.05) smaller 24 hour activity spaces compared to wild conspecifics, staying in close proximity to the ecotourism site; Fed stingrays showed a high degree of overlap in their core activity spaces compared to wild stingrays which were largely solitary in the spaces utilized (72% vs. 3% overlap respectively). Supplemental feeding has strikingly altered movement behavior and spatial distribution of the stingrays, and generated an atypically high density of animals at SCS which could have downstream fitness costs for individuals and potentially broader ecosystem effects. These findings should help environmental managers plan mitigating measures for existing operations, and

  11. Activation of the aryl hydrocarbon receptor by carbaryl: Computational evidence of the ability of carbaryl to assume a planar conformation.

    PubMed

    Casado, Susana; Alonso, Mercedes; Herradón, Bernardo; Tarazona, José V; Navas, José

    2006-12-01

    It has been accepted that aryl hydrocarbon receptor (AhR) ligands are compounds with two or more aromatic rings in a coplanar conformation. Although general agreement exists that carbaryl is able to activate the AhR, it has been proposed that such activation could occur through alternative pathways without ligand binding. This idea was supported by studies showing a planar conformation of carbaryl as unlikely. The objective of the present work was to clarify the process of AhR activation by carbaryl. In rat H4IIE cells permanently transfected with a luciferase gene under the indirect control of AhR, incubation with carbaryl led to an increase of luminescence. Ligand binding to the AhR was studied by means of a cell-free in vitro system in which the activation of AhR can occur only by ligand binding. In this system, exposure to carbaryl also led to activation of AhR. These results were similar to those obtained with the AhR model ligand beta-naphthoflavone, although this compound exhibited higher potency than carbaryl in both assays. By means of computational modeling (molecular mechanics and quantum chemical calculations), the structural characteristics and electrostatic properties of carbaryl were described in detail, and it was observed that the substituent at C-1 and the naphthyl ring were not coplanar. Assuming that carbaryl would interact with the AhR through a hydrogen bond, this interaction was studied computationally using hydrogen fluoride as a model H-bond donor. Under this situation, the stabilization energy of the carbaryl molecule would permit it to adopt a planar conformation. These results are in accordance with the mechanism traditionally accepted for AhR activation: Binding of ligands in a planar conformation.

  12. Active Collisions in Altered Gravity Reveal Eye-Hand Coordination Strategies

    PubMed Central

    White, Olivier; Lefèvre, Philippe; Wing, Alan M.; Bracewell, R. Martyn; Thonnard, Jean-Louis

    2012-01-01

    Most object manipulation tasks involve a series of actions demarcated by mechanical contact events, and gaze is usually directed to the locations of these events as the task unfolds. Typically, gaze foveates the target 200 ms in advance of the contact. This strategy improves manual accuracy through visual feedback and the use of gaze-related signals to guide the hand/object. Many studies have investigated eye-hand coordination in experimental and natural tasks; most of them highlighted a strong link between eye movements and hand or object kinematics. In this experiment, we analyzed gaze strategies in a collision task but in a very challenging dynamical context. Participants performed collisions while they were exposed to alternating episodes of microgravity, hypergravity and normal gravity. First, by isolating the effects of inertia in microgravity, we found that peak hand acceleration marked the transition between two modes of grip force control. Participants exerted grip forces that paralleled load force profiles, and then increased grip up to a maximum shifted after the collision. Second, we found that the oculomotor strategy adapted visual feedback of the controlled object around the collision, as demonstrated by longer durations of fixation after collision in new gravitational environments. Finally, despite large variability of arm dynamics in altered gravity, we found that saccades were remarkably time-locked to the peak hand acceleration in all conditions. In conclusion, altered gravity allowed light to be shed on predictive mechanisms used by the central nervous system to coordinate gaze, hand and grip motor actions during a mixed task that involved transport of an object and high impact loads. PMID:22984488

  13. Active collisions in altered gravity reveal eye-hand coordination strategies.

    PubMed

    White, Olivier; Lefèvre, Philippe; Wing, Alan M; Bracewell, R Martyn; Thonnard, Jean-Louis

    2012-01-01

    Most object manipulation tasks involve a series of actions demarcated by mechanical contact events, and gaze is usually directed to the locations of these events as the task unfolds. Typically, gaze foveates the target 200 ms in advance of the contact. This strategy improves manual accuracy through visual feedback and the use of gaze-related signals to guide the hand/object. Many studies have investigated eye-hand coordination in experimental and natural tasks; most of them highlighted a strong link between eye movements and hand or object kinematics. In this experiment, we analyzed gaze strategies in a collision task but in a very challenging dynamical context. Participants performed collisions while they were exposed to alternating episodes of microgravity, hypergravity and normal gravity. First, by isolating the effects of inertia in microgravity, we found that peak hand acceleration marked the transition between two modes of grip force control. Participants exerted grip forces that paralleled load force profiles, and then increased grip up to a maximum shifted after the collision. Second, we found that the oculomotor strategy adapted visual feedback of the controlled object around the collision, as demonstrated by longer durations of fixation after collision in new gravitational environments. Finally, despite large variability of arm dynamics in altered gravity, we found that saccades were remarkably time-locked to the peak hand acceleration in all conditions. In conclusion, altered gravity allowed light to be shed on predictive mechanisms used by the central nervous system to coordinate gaze, hand and grip motor actions during a mixed task that involved transport of an object and high impact loads.

  14. DNA structural alterations induced by bis-netropsins modulate human DNA topoisomerase I cleavage activity and poisoning by camptothecin.

    PubMed

    Sukhanova, Alyona; Grokhovsky, Sergei; Ermishov, Michael; Mochalov, Konstantin; Zhuze, Alexei; Oleinikov, Vladimir; Nabiev, Igor

    2002-07-01

    Bis-netropsins (bis-Nts) are efficient catalytic inhibitors of human DNA topoisomerase I (top I). These DNA minor groove binders are considered to serve as suppressors of top I-linked DNA breaks, which is generally believed to be related to their affinity to DNA. In this study, it was found that bis-Nts exhibit sequence-specificity of suppression of the strong top I-specific DNA cleavage sites and that this sequence-specificity is determined by differential ligand-induced structural alterations of DNA. Raman scattering analysis of bis-Nts interactions with double-stranded oligonucleotides, each containing the site of specific affinity to one of bis-Nts and a distinctly located top I degenerate consensus, demonstrated that bis-Nts induce not only structural changes in duplex DNA at their loading position, but also conformational changes in a distant top I-specific DNA cleavage site. The ability to alter the DNA structure correlates with the anti-top I inhibitory activities of the ligands. In addition, DNA structural alterations induced by bis-Nts were shown to be responsible for modulation of the camptothecin (CPT)-mediated DNA cleavage by top I. This effect is expressed in the bis-Nts-induced enhancement of some of the CPT-dependent DNA cleavage sites as well as in the CPT-induced enhancement of some of the top I-specific DNA cleavage sites suppressed by bis-Nts in the absence of CPT. PMID:12106608

  15. Does Changing the Predicted Dynamics of a Phospholipase C Alter Activity and Membrane Binding?

    PubMed Central

    Cheng, Jiongjia; Karri, Sashank; Grauffel, Cédric; Wang, Fang; Reuter, Nathalie; Roberts, Mary F.; Wintrode, Patrick L.; Gershenson, Anne

    2013-01-01

    The enzymatic activity of secreted phosphatidylinositol-specific phospholipase C (PI-PLC) enzymes is associated with bacterial virulence. Although the PI-PLC active site has no obvious lid, molecular-dynamics simulations suggest that correlated loop motions may limit access to the active site, and two Pro residues, Pro245 and Pro254, are associated with these correlated motions. Whereas the region containing both Pro residues is quite variable among PI-PLCs, it shows high conservation in virulence-associated, secreted PI-PLCs that bind to the surface of cells. These regions of the protein are also associated with phosphatidylcholine binding, which enhances PI-PLC activity. In silico mutagenesis of Pro245 disrupts correlated motions between the two halves of Bacillus thuringiensis PI-PLC, and Pro245 variants show significantly reduced enzymatic activity in all assay systems. PC still enhanced activity, but not to the level of wild-type enzyme. Mutagenesis of Pro254 appears to stiffen the PI-PLC structure, but experimental mutations had minor effects on activity and membrane binding. With the exception of P245Y, reduced activity was not associated with reduced membrane affinity. This combination of simulations and experiments suggests that correlated motions between the two halves of PI-PLC may be more important for enzymatic activity than for vesicle binding. PMID:23332071

  16. Binding among select episodic elements is altered via active short-term retrieval.

    PubMed

    Bridge, Donna J; Voss, Joel L

    2015-08-01

    Of the many elements that comprise an episode, are any disproportionately bound to the others? We tested whether active short-term retrieval selectively increases binding. Individual objects from multiobject displays were retrieved after brief delays. Memory was later tested for the other objects. Cueing with actively retrieved objects facilitated memory of associated objects, which was associated with unique patterns of viewing behavior during study and enhanced ERP correlates of retrieval during test, relative to other reminder cues that were not actively retrieved. Active short-term retrieval therefore enhanced binding of retrieved elements with others, thus creating powerful memory cues for entire episodes. PMID:26179229

  17. Short-term withdrawal from developmental exposure to cocaine activates the glucocorticoid receptor and alters spine dynamics.

    PubMed

    Caffino, Lucia; Giannotti, Giuseppe; Malpighi, Chiara; Racagni, Giorgio; Fumagalli, Fabio

    2015-10-01

    Although glucocorticoid receptors (GRs) contribute to the action of cocaine, their role following developmental exposure to the psychostimulant is still unknown. To address this issue, we exposed adolescent male rats to cocaine (20mg/kg/day) from post-natal day (PND) 28 to PND 42 and sacrificed them at PND 45 or 90. We studied the medial prefrontal cortex (mPFC), a brain region that is still developing during adolescence. In PND 45 rats we found enhanced GR transcription and translation as well as increased trafficking toward the nucleus of the receptor, with no alteration in plasma corticosterone levels. We also showed reduced expression of the GR co-chaperone FKBP51, that normally keeps the receptor in the cytoplasm, and increased expression of Src1, which cooperates in the activation of GR transcriptional activity, revealing that short withdrawal alters the finely tuned mechanisms regulating GR action. Since activation of GRs regulate dendritic spine morphology, we next investigated spine dynamics in cocaine-withdrawn rats. We found that PSD95, cofilin and F-actin, molecules regulating spine actin network, are reduced in the mPFC of PND 45 rats suggesting reduced spine density, confirmed by confocal imaging. Further, formation of filopodia, i.e. the inactive spines, is enhanced suggesting the formation of non-functional spines. Of note, no changes were found in molecules related to GR machinery or spine dynamics following long-term abstinence, i.e. in adult rats (PND 90). These findings demonstrate that short withdrawal promotes plastic changes in the developing brain via the dysregulation of the GR system and alterations in the spine network. PMID:26004981

  18. A new strategy to analyze possible association structures between dynamic nocturnal hormone activities and sleep alterations in humans.

    PubMed

    Kalus, Stefanie; Kneib, Thomas; Steiger, Axel; Holsboer, Florian; Yassouridis, Alexander

    2009-04-01

    The human sleep process shows dynamic alterations during the night. Methods are needed to examine whether and to what extent such alterations are affected by internal, possibly time-dependent, factors, such as endocrine activity. In an observational study, we examined simultaneously sleep EEG and nocturnal levels of renin, growth hormone (GH), and cortisol (between 2300 and 0700) in 47 healthy volunteers comprising 24 women (41.67 +/- 2.93 yr of age) and 23 men (37.26 +/- 2.85 yr of age). Hormone concentrations were measured every 20 min. Conventional sleep stage scoring at 30-s intervals was applied. Semiparametric multinomial logit models are used to study and quantify possible time-dependent hormone effects on sleep stage transition courses. Results show that increased cortisol levels decrease the probability of transition from rapid-eye-movement (REM) sleep to wakefulness (WAKE) and increase the probability of transition from REM to non-REM (NREM) sleep, irrespective of the time in the night. Via the model selection criterion Akaike's information criterion, it was found that all considered hormone effects on transition probabilities with the initial state WAKE change with time. Similarly, transition from slow-wave sleep (SWS) to light sleep (LS) is affected by a "hormone-time" interaction for cortisol and renin, but not GH. For example, there is a considerable increase in the probability of SWS-LS transition toward the end of the night, when cortisol concentrations are very high. In summary, alterations in human sleep possess dynamic forms and are partially influenced by the endocrine activity of certain hormones. Statistical methods, such as semiparametric multinomial and time-dependent logit regression, can offer ambitious ways to investigate and estimate the association intensities between the nonstationary sleep changes and the time-dependent endocrine activities. PMID:19144755

  19. Highly active modulators of indole signaling alter pathogenic behaviors in Gram-negative and Gram-positive bacteria.

    PubMed

    Minvielle, Marine J; Eguren, Kristen; Melander, Christian

    2013-12-16

    Indole is a universal signal that regulates various bacterial behaviors, such as biofilm formation and antibiotic resistance. To generate mechanistic probes of indole signaling and control indole-mediated pathogenic phenotypes in both Gram-positive and Gram-negative bacteria, we have investigated the use of desformylflustrabromine (dFBr) derivatives to generate highly active indole mimetics. We have developed non-microbicidal dFBr derivatives that are 27-2000 times more active than indole in modulating biofilm formation, motility, acid resistance, and antibiotic resistance. The activity of these analogues parallels indole, because they are dependent on temperature, the enzyme tryptophanase TnaA, and the transcriptional regulator SdiA. This investigation demonstrates that molecules based on the dFBr scaffold can alter pathogenic behaviors by mimicking indole-signaling pathways.

  20. Differential Larval Toxicity and Oviposition Altering Activity of Some Indigenous Plant Extracts against Dengue and Chikungunya Vector Aedes albopictus

    PubMed Central

    Yadav, Ruchi; Tyagi, Varun; Tikar, Sachin N; Sharma, Ajay K; Mendki, Murlidhar J; Jain, Ashok K; Sukumaran, Devanathan

    2014-01-01

    Background: Mosquitoes are well known as vectors of several disease causing pathogens. The extensive use of synthetic insecticides in the mosquito control strategies resulted to the development of pesticide resistance and fostered environmental deterioration. Hence in recent years plants become alternative source of mosquito control agents. The present study assessed the larvicidal and oviposition altering activity of six different plants species-Alstonia scholaris, Callistemon viminalis, Hyptis suaveolens, Malvastrum coromandelianum, Prosopis juliflora, Vernonia cinerea against Aedes albopictus mosquito in laboratory. Methods: Leaf extracts of all the six plants species in five different solvents of various polarities were used in the range of 20–400ppm for larval bioassay and 50,100 and 200ppm for cage bioassay (for the study of oviposition behavior) against Ae. albopictus. The larval mortality data were recorded after 24 h and subjected to Probit analysis to determine the lethal concentrations (LC50), while OAI (Oviposition activity index) was calculated for oviposition altering activity of the plant extracts. Results: Vernonia cinerea extract in acetone and C. viminalis extract in isopropanol were highly effective against Aedes albopictus larvae with LC50 value 64.57, 71.34ppm respectively. Acetone extract of P. juliflora found to be strong oviposition-deterrent which inhibited >2 fold egg laying (OAI-0.466) at 100ppm. Conclusion: Vernonia cinerea and C. viminallis leaf extracts have the potential to be used as larvicide and P. juliflora as an oviposition-deterrent for the control of Ae. albopictus mosquito. PMID:26114131

  1. Altered Spontaneous Brain Activity in Patients with Acute Spinal Cord Injury Revealed by Resting-State Functional MRI

    PubMed Central

    Zhu, Ling; Wu, Guangyao; Zhou, Xin; Li, Jielan; Wen, Zhi; Lin, Fuchun

    2015-01-01

    Background Previous neuroimaging studies have provided evidence of structural and functional reorganization of brain in patients with chronic spinal cord injury (SCI). However, it remains unknown whether the spontaneous brain activity changes in acute SCI. In this study, we investigated intrinsic brain activity in acute SCI patients using a regional homogeneity (ReHo) analysis based on resting-state functional magnetic resonance imaging. Methods A total of 15 patients with acute SCI and 16 healthy controls participated in the study. The ReHo value was used to evaluate spontaneous brain activity, and voxel-wise comparisons of ReHo were performed to identify brain regions with altered spontaneous brain activity between groups. We also assessed the associations between ReHo and the clinical scores in brain regions showing changed spontaneous brain activity. Results Compared with the controls, the acute SCI patients showed decreased ReHo in the bilateral primary motor cortex/primary somatosensory cortex, bilateral supplementary motor area/dorsal lateral prefrontal cortex, right inferior frontal gyrus, bilateral dorsal anterior cingulate cortex and bilateral caudate; and increased ReHo in bilateral precuneus, the left inferior parietal lobe, the left brainstem/hippocampus, the left cingulate motor area, bilateral insula, bilateral thalamus and bilateral cerebellum. The average ReHo values of the left thalamus and right insula were negatively correlated with the international standards for the neurological classification of spinal cord injury motor scores. Conclusion Our findings indicate that acute distant neuronal damage has an immediate impact on spontaneous brain activity. In acute SCI patients, the ReHo was prominently altered in brain regions involved in motor execution and cognitive control, default mode network, and which are associated with sensorimotor compensatory reorganization. Abnormal ReHo values in the left thalamus and right insula could serve as

  2. Effect of dietary and hormonal alterations on the activity of 3-methylcrotonyl-CoA carboylase in rat liver

    SciTech Connect

    Paul, H.S.; Gleditsch, C.E.; Adibi, S.A.

    1986-05-01

    Previous studies have established that activities of leucine transaminase and branched-chain keto acid dehydrogenase (BCKDH) are under metabolic control. In the present experiment, the authors have investigated whether activity of 3-methylcrotonyl-CoA carboxylase (MCase), an enzyme distal to BCKDH in pathways of leucine oxidation, is also subjected to metabolic regulation. Initially, they developed optimal conditions to assay the activity of this enzyme. The assay was based on the incorporation of /sup 14/CO/sub 2/ into 3-methylcrotonyl-CoA (MC-CoA) by liver mitochondria and required the presence of ATP and biotin. Subsequently, the authors determined the activity (nmol /sup 14/CO/sub 2/ incorporated/mg protein/min, mean +/- SE, 6 rats) of MCase under normal (2.80 +/- 0.09) and altered conditions. The activity of MCase was not affected either by starvation (2.88 +/- 0.13), diabetes (2.95 +/- 0.11), low-protein (2.35 +/- 0.05), or high-protein diet (3.06 +/- 0.06). To further substantiate these results, they measured accumulation of MC-CoA by incubating liver mitochondria with ..cap alpha..-ketoisocaproate (KIC). Of the KIC fraction that underwent flux through BCKDH (2.15 +/- 0.14 nmol/mg protein/min), only 0.26% accumulated as MC-CoA. Even if diabetes, when the flux through BCKDH was significantly increased (3.62 +/- 0.36), the accumulation of MC-CoA was negligible (0.33%). The authors conclude that a) MCase activity does not change in response to dietary and hormonal alterations, and b) MCase is not a rate-limiting reaction in pathways of leucine oxidation.

  3. Alterations in Membrane Caveolae and BKCa Channel Activity in Skin Fibroblasts in Smith-Lemli-Opitz Syndrome

    PubMed Central

    Ren, Gongyi; Jacob, Robert F.; Kaulin, Yuri; DiMuzio, Paul; Xie, Yi; Mason, R. Preston; Tint, G. Stephen; Steiner, Robert D.; Roulett, Jean-Baptiste; Merkens, Louise; Whitaker-Mendez, Diana; Frank, Phillipe G.; Lisanti, Michael; Cox, Robert H.; Tulenko, Thomas N.

    2011-01-01

    The Smith-Lemli-Opitz syndrome (SLOS) is an inherited disorder of cholesterol synthesis caused by mutations in DHCR7 which encodes the final enzyme in the cholesterol synthesis pathway. The immediate precursor to cholesterol synthesis, 7-dehydrocholesterol (7-DHC) accumulates in the plasma and cells of SLOS patients which has led to the idea that the accumulation of abnormal sterols and/or reduction in cholesterol underlies the phenotypic abnormalities of SLOS. We tested the hypothesis that 7-DHC accumulates in membrane caveolae where it disturbs caveolar bilayer structure-function. Membrane caveolae from skin fibroblasts obtained from SLOS patients were isolated and found to accumulate 7-DHC. In caveolar-like model membranes containing 7-DHC, subtle, but complex alterations in intermolecular packing, lipid order and membrane width were observed. In addition, the BKCa K+ channel, which co-migrates with caveolin-1 in a membrane fraction enriched with cholesterol, was impaired in SLOS cells as reflected by reduced single channel conductance and a 50 mV rightward shift in the channel activation voltage. In addition, a marked decrease in BKCa protein but not mRNA expression levels were seen suggesting post-translational alterations. Accompanying these changes was a reduction in caveolin-1 protein and mRNA levels, but membrane caveolar structure was not altered. These results are consistent with the hypothesis that 7-DHC accumulation in the caveolar membrane results in defective caveolar signaling. However, additional cellular alterations beyond mere changes associated with abnormal sterols in the membrane likely contribute to the pathogenesis of SLOS. PMID:21724437

  4. Overexpression of cerebral and hepatic cytochrome P450s alters behavioral activity of rat offspring following prenatal exposure to lindane

    SciTech Connect

    Johri, Ashu; Yadav, Sanjay; Dhawan, Alok; Parmar, Devendra

    2007-12-15

    Oral administration of different doses (0.0625, 0.125 or 0.25 mg/kg corresponding to 1/1400th, 1/700th or 1/350th of LD{sub 50}) of lindane to the pregnant Wistar rats from gestation days 5 to 21 were found to produce a dose-dependent increase in the activity of cytochrome P450 (CYP)-dependent 7-ethoxyresorufin-O-deethylase (EROD), 7-pentoxyresorufin-O-dealkylase (PROD) and N-nitrosodimethylamine demethylase (NDMA-d) in brain and liver of offspring postnatally at 3 weeks. The increase in the activity of CYP monooxygenases was found to be associated with the increase in the mRNA and protein expression of xenobiotic metabolizing CYP1A, 2B and 2E1 isoenzymes in the brain and liver of offspring. Dose-dependent alterations in the parameters of spontaneous locomotor activity in the offspring postnatally at 3 weeks have suggested that increase in CYP activity may possibly lead to the formation of metabolites to the levels that may be sufficient to alter the behavioral activity of the offspring. Interestingly, the inductive effect on cerebral and hepatic CYPs was found to persist postnatally up to 6 weeks in the offspring at the relatively higher doses (0.125 and 0.25 mg/kg) of lindane and up to 9 weeks at the highest dose (0.25 mg/kg), though the magnitude of induction was less than that observed at 3 weeks. Alterations in the parameters of spontaneous locomotor activity in the offspring postnatally at 6 and 9 weeks, though significant only in the offspring at 3 and 6-week of age, have further indicated that due to the reduced activity of the CYPs during the ontogeny, lindane and its metabolites may not be effectively cleared from the brain. The data suggest that low dose prenatal exposure to the pesticide has the potential to produce overexpression of xenobiotic metabolizing CYPs in brain and liver of the offspring which may account for the behavioral changes observed in the offspring.

  5. Binding among Select Episodic Elements Is Altered via Active Short-Term Retrieval

    ERIC Educational Resources Information Center

    Bridge, Donna J.; Voss, Joel L.

    2015-01-01

    Of the many elements that comprise an episode, are any disproportionately bound to the others? We tested whether active short-term retrieval selectively increases binding. Individual objects from multiobject displays were retrieved after brief delays. Memory was later tested for the other objects. Cueing with actively retrieved objects facilitated…

  6. Masked Priming Effects in Aphasia: Evidence of Altered Automatic Spreading Activation

    ERIC Educational Resources Information Center

    Silkes, JoAnn P.; Rogers, Margaret A.

    2012-01-01

    Purpose: Previous research has suggested that impairments of automatic spreading activation may underlie some aphasic language deficits. The current study further investigated the status of automatic spreading activation in individuals with aphasia as compared with typical adults. Method: Participants were 21 individuals with aphasia (12 fluent, 9…

  7. Molecular kinetics. Ras activation by SOS: allosteric regulation by altered fluctuation dynamics.

    PubMed

    Iversen, Lars; Tu, Hsiung-Lin; Lin, Wan-Chen; Christensen, Sune M; Abel, Steven M; Iwig, Jeff; Wu, Hung-Jen; Gureasko, Jodi; Rhodes, Christopher; Petit, Rebecca S; Hansen, Scott D; Thill, Peter; Yu, Cheng-Han; Stamou, Dimitrios; Chakraborty, Arup K; Kuriyan, John; Groves, Jay T

    2014-07-01

    Activation of the small guanosine triphosphatase H-Ras by the exchange factor Son of Sevenless (SOS) is an important hub for signal transduction. Multiple layers of regulation, through protein and membrane interactions, govern activity of SOS. We characterized the specific activity of individual SOS molecules catalyzing nucleotide exchange in H-Ras. Single-molecule kinetic traces revealed that SOS samples a broad distribution of turnover rates through stochastic fluctuations between distinct, long-lived (more than 100 seconds), functional states. The expected allosteric activation of SOS by Ras-guanosine triphosphate (GTP) was conspicuously absent in the mean rate. However, fluctuations into highly active states were modulated by Ras-GTP. This reveals a mechanism in which functional output may be determined by the dynamical spectrum of rates sampled by a small number of enzymes, rather than the ensemble average.

  8. Structure-Based Alteration of Substrate Specificity and Catalytic Activity of Sulfite Oxidase from Sulfite Oxidation to Nitrate Reduction

    SciTech Connect

    Qiu, James A.; Wilson, Heather L.; Rajagopalan, K.V.

    2012-04-18

    Eukaryotic sulfite oxidase is a dimeric protein that contains the molybdenum cofactor and catalyzes the metabolically essential conversion of sulfite to sulfate as the terminal step in the metabolism of cysteine and methionine. Nitrate reductase is an evolutionarily related molybdoprotein in lower organisms that is essential for growth on nitrate. In this study, we describe human and chicken sulfite oxidase variants in which the active site has been modified to alter substrate specificity and activity from sulfite oxidation to nitrate reduction. On the basis of sequence alignments and the known crystal structure of chicken sulfite oxidase, two residues are conserved in nitrate reductases that align with residues in the active site of sulfite oxidase. On the basis of the crystal structure of yeast nitrate reductase, both positions were mutated in human sulfite oxidase and chicken sulfite oxidase. The resulting double-mutant variants demonstrated a marked decrease in sulfite oxidase activity but gained nitrate reductase activity. An additional methionine residue in the active site was proposed to be important in nitrate catalysis, and therefore, the triple variant was also produced. The nitrate reducing ability of the human sulfite oxidase triple mutant was nearly 3-fold greater than that of the double mutant. To obtain detailed structural data for the active site of these variants, we introduced the analogous mutations into chicken sulfite oxidase to perform crystallographic analysis. The crystal structures of the Mo domains of the double and triple mutants were determined to 2.4 and 2.1 {angstrom} resolution, respectively.

  9. Bifunctional Probes of Cathepsin Protease Activity and pH Reveal Alterations in Endolysosomal pH during Bacterial Infection.

    PubMed

    Sanman, Laura E; van der Linden, Wouter A; Verdoes, Martijn; Bogyo, Matthew

    2016-07-21

    Cysteine cathepsins are lysosomal proteases involved in regulation of both normal cellular processes and disease. Biochemical studies with peptide substrates indicate that cathepsins have optimal activity at acidic pH and highly attenuated activity at neutral pH. In contrast, there is mounting evidence that cathepsins have biological roles in environments that have non-acidic pH. To further define the specific pH environments where cathepsins act, we designed bifunctional activity-based probes (ABPs) that allow simultaneous analysis of cathepsin protease activity and pH. We use these probes to analyze the steady-state environment of cathepsin activity in macrophages and to measure dynamic changes in activity and pH upon stimulation. We show that Salmonella typhimurium induces a change in lysosomal pH that ultimately impairs cathepsin activity in both infected cells and a fraction of bystander cells, highlighting a mechanism by which Salmonella can simultaneously flourish within host cells and alter the behavior of nearby uninfected cells.

  10. Methionine-choline deprivation alters liver and brain acetylcholinesterase activity in C57BL6 mice.

    PubMed

    Vučević, Danijela B; Cerović, Ivana B; Mladenović, Dušan R; Vesković, Milena N; Stevanović, Ivana; Jorgačević, Bojan Z; Ješić Vukićević, Rada; Radosavljević, Tatjana S

    2016-07-01

    Choline and methionine are precursors of acetylcholine, whose hydrolysis is catalyzed by acetylcholinesterase (AChE). Considering the possibility of their common deficiency, we investigated the influence of methionine-choline deprivation on AChE activity in liver and various brain regions (hypothalamus, hippocampus, cerebral cortex and striatum) in mice fed with methionine-choline deficient (MCD) diet. Male C57BL/6 mice (n = 28) were randomly and equally divided into following groups: control group fed with standard diet for 6 weeks (C) and groups fed with MCD diet for 2 weeks (MCD2), 4 weeks (MCD4) and for 6 weeks (MCD6). After the diet, mice were sacrificied and AChE activity in liver and brain was determined spectrophotometrically. Hepatic AChE activity was higher in MCD2, MCD4 and MCD6 compared to control (p < 0.01), with most prominent increase in MCD6. AChE activity in hypothalamus was higher in MCD4 and MCD6 vs. control (p < 0.05 and p < 0.01, respectively), as well as in MCD6 compared to MCD4 (p < 0.01). In hippocampus, increase in AChE activity was shown in MCD6 compared to control (p < 0.01). In cortex and striatum, increase in AChE activity was noted in MCD6 compared to control (p < 0.05). Our findings indicate the increase of hepatic and brain AChE activity in mice caused by methionine-choline deprivation.

  11. Alterations in leukocyte transcriptional control pathway activity associated with major depressive disorder and antidepressant treatment.

    PubMed

    Mellon, S H; Wolkowitz, O M; Schonemann, M D; Epel, E S; Rosser, R; Burke, H B; Mahan, L; Reus, V I; Stamatiou, D; Liew, C-C; Cole, S W

    2016-01-01

    Major depressive disorder (MDD) is associated with a significantly elevated risk of developing serious medical illnesses such as cardiovascular disease, immune impairments, infection, dementia and premature death. Previous work has demonstrated immune dysregulation in subjects with MDD. Using genome-wide transcriptional profiling and promoter-based bioinformatic strategies, we assessed leukocyte transcription factor (TF) activity in leukocytes from 20 unmedicated MDD subjects versus 20 age-, sex- and ethnicity-matched healthy controls, before initiation of antidepressant therapy, and in 17 of the MDD subjects after 8 weeks of sertraline treatment. In leukocytes from unmedicated MDD subjects, bioinformatic analysis of transcription control pathway activity indicated an increased transcriptional activity of cAMP response element-binding/activating TF (CREB/ATF) and increased activity of TFs associated with cellular responses to oxidative stress (nuclear factor erythroid-derived 2-like 2, NFE2l2 or NRF2). Eight weeks of antidepressant therapy was associated with significant reductions in Hamilton Depression Rating Scale scores and reduced activity of NRF2, but not in CREB/ATF activity. Several other transcriptional regulation pathways, including the glucocorticoid receptor (GR), nuclear factor kappa-B cells (NF-κB), early growth response proteins 1-4 (EGR1-4) and interferon-responsive TFs, showed either no significant differences as a function of disease or treatment, or activities that were opposite to those previously hypothesized to be involved in the etiology of MDD or effective treatment. Our results suggest that CREB/ATF and NRF2 signaling may contribute to MDD by activating immune cell transcriptome dynamics that ultimately influence central nervous system (CNS) motivational and affective processes via circulating mediators. PMID:27219347

  12. Alterations in leukocyte transcriptional control pathway activity associated with major depressive disorder and antidepressant treatment

    PubMed Central

    Mellon, S H; Wolkowitz, O M; Schonemann, M D; Epel, E S; Rosser, R; Burke, H B; Mahan, L; Reus, V I; Stamatiou, D; Liew, C -C; Cole, S W

    2016-01-01

    Major depressive disorder (MDD) is associated with a significantly elevated risk of developing serious medical illnesses such as cardiovascular disease, immune impairments, infection, dementia and premature death. Previous work has demonstrated immune dysregulation in subjects with MDD. Using genome-wide transcriptional profiling and promoter-based bioinformatic strategies, we assessed leukocyte transcription factor (TF) activity in leukocytes from 20 unmedicated MDD subjects versus 20 age-, sex- and ethnicity-matched healthy controls, before initiation of antidepressant therapy, and in 17 of the MDD subjects after 8 weeks of sertraline treatment. In leukocytes from unmedicated MDD subjects, bioinformatic analysis of transcription control pathway activity indicated an increased transcriptional activity of cAMP response element-binding/activating TF (CREB/ATF) and increased activity of TFs associated with cellular responses to oxidative stress (nuclear factor erythroid-derived 2-like 2, NFE2l2 or NRF2). Eight weeks of antidepressant therapy was associated with significant reductions in Hamilton Depression Rating Scale scores and reduced activity of NRF2, but not in CREB/ATF activity. Several other transcriptional regulation pathways, including the glucocorticoid receptor (GR), nuclear factor kappa-B cells (NF-κB), early growth response proteins 1–4 (EGR1–4) and interferon-responsive TFs, showed either no significant differences as a function of disease or treatment, or activities that were opposite to those previously hypothesized to be involved in the etiology of MDD or effective treatment. Our results suggest that CREB/ATF and NRF2 signaling may contribute to MDD by activating immune cell transcriptome dynamics that ultimately influence central nervous system (CNS) motivational and affective processes via circulating mediators. PMID:27187237

  13. Altered activities of anti-atherogenic enzymes LCAT, paraoxonase, and platelet-activating factor acetylhydrolase in atherosclerosis-susceptible mice.

    PubMed

    Forte, Trudy M; Subbanagounder, Ganesamoorthy; Berliner, Judith A; Blanche, Patricia J; Clermont, Anne O; Jia, Zhen; Oda, Michael N; Krauss, Ronald M; Bielicki, John K

    2002-03-01

    We examined whether the putative anti-atherogenic enzymes LCAT, paraoxonase (PON), and platelet-activating factor acetylhydrolase (PAF-AH) are impaired in 8 week old atherosclerosis susceptible apolipoprotein E (apoE)(-/-) and LDL receptor (LDLr)(-/-) mice and whether plasma concentrations of bioactive oxidized phospholipids accumulate in plasma. ApoE(-/-) mice had reduced (28%) LCAT activity and elevated lysophosphatidylcholine and bioactive oxidized phospholipids (1-palmitoyl-2-oxovaleryl-sn-glycero-3-phosphocholine and 1-palmitoyl-2-glutaryl-sn-glycero-3-phosphocholine) compared with controls on the chow diet. Elevated oxidized phospholipids and reduced LCAT activity may, in part, contribute to spontaneous lesions in these mice on a chow diet. A Western diet decreased LCAT activity further (50% of controls) and PON activity was decreased 38%. The LDLr(-/-) mice showed normal LCAT activity on chow diet and little accumulation of oxidized phospholipids. On a Western diet, LDLr(-/-) mice had reduced LCAT activity (21%), but no change in PON activity. All genotypes had reduced PAF-AH activity on the Western diet. ApoE(-/-) and LDLr(-/-) mice, but not controls, had elevated plasma bioactive oxidized phospholipids on the Western diet. We conclude that impairment of LCAT activity and accumulation of oxidized phospholipids are part of an early atherogenic phenotype in these models.

  14. Low Concentration of Silver Nanoparticles Not Only Enhances the Activity of Horseradish Peroxidase but Alter the Structure Also

    PubMed Central

    Karim, Zoheb; Adnan, Rohana; Ansari, Mohd Saquib

    2012-01-01

    Chemical synthesis of Ag-NPs was carried out using reduction method. The reduction mechanistic approach of silver ions was found to be a basic clue for the formation of the Ag-NPs. The nanoparticles were characterized by UV-vis, FT-IR and TEM analysis. We had designed some experiments in support of our hypothesis, “low concentrations of novel nanoparticles (silver and gold) increases the activity of plant peroxidases and alter their structure also”, we had used Ag-NPs and HRP as models. The immobilization/interaction experiment had demonstrated the specific concentration range of the Ag-NPs and within this range, an increase in HRP activity was reported. At 0.08 mM concentration of Ag-NPs, 50% increase in the activity yield was found. The U.V-vis spectra had demonstrated the increase in the absorbance of HRP within the reported concentration range (0.06–0.12 mM). Above and below this concentration range there was a decrease in the activity of HRP. The results that we had found from the fluorescence spectra were also in favor of our hypothesis. There was a maximum increase in ellipticity and α-helix contents in the presence of 0.08 mM concentration of Ag-NPs, demonstrated by circular dichroism (CD) spectra. Finally, incubation of a plant peroxidase, HRP with Ag-NPs, within the reported concentration range not only enhances the activity but also alter the structure. PMID:22848490

  15. Altered Spontaneous Brain Activity in Cortical and Subcortical Regions in Parkinson's Disease.

    PubMed

    Xiang, Jie; Jia, Xiuqin; Li, Huizhuo; Qin, Jiawei; Liang, Peipeng; Li, Kuncheng

    2016-01-01

    Purpose. The present study aimed to explore the changes of amplitude of low-frequency fluctuations (ALFF) at rest in patients with Parkinson's disease (PD). Methods. Twenty-four PD patients and 22 healthy age-matched controls participated in the study. ALFF was measured on the whole brain of all participants. A two-sample t-test was then performed to detect the group differences with age, gender, education level, head motion, and gray matter volume as covariates. Results. It was showed that PD patients had significantly decreased ALFF in the left thalamus/caudate and right insula/inferior prefrontal gyrus, whereas they had increased ALFF in the right medial prefrontal cortex (BA 8/6) and dorsolateral prefrontal cortex (BA 9/10). Conclusions. Our results indicated that significant alterations of ALFF in the subcortical regions and prefrontal cortex have been detected in PD patients, independent of age, gender, education, head motion, and structural atrophy. The current findings further provide insights into the biological mechanism of the disease.

  16. Altered Spontaneous Brain Activity in Cortical and Subcortical Regions in Parkinson's Disease

    PubMed Central

    Xiang, Jie; Jia, Xiuqin; Li, Huizhuo; Qin, Jiawei; Li, Kuncheng

    2016-01-01

    Purpose. The present study aimed to explore the changes of amplitude of low-frequency fluctuations (ALFF) at rest in patients with Parkinson's disease (PD). Methods. Twenty-four PD patients and 22 healthy age-matched controls participated in the study. ALFF was measured on the whole brain of all participants. A two-sample t-test was then performed to detect the group differences with age, gender, education level, head motion, and gray matter volume as covariates. Results. It was showed that PD patients had significantly decreased ALFF in the left thalamus/caudate and right insula/inferior prefrontal gyrus, whereas they had increased ALFF in the right medial prefrontal cortex (BA 8/6) and dorsolateral prefrontal cortex (BA 9/10). Conclusions. Our results indicated that significant alterations of ALFF in the subcortical regions and prefrontal cortex have been detected in PD patients, independent of age, gender, education, head motion, and structural atrophy. The current findings further provide insights into the biological mechanism of the disease. PMID:27413576

  17. Transient alterations in neuronal and behavioral activity following bensultap and fipronil treatment in rats.

    PubMed

    Szegedi, Viktor; Bárdos, György; Détári, László; Tóth, Attila; Banczerowski-Pelyhe, Ilona; Világi, Ildikó

    2005-10-15

    In the present multilevel study, neuromodulatory effect of two insecticides, bensultap and fipronil were investigated in rats. Although the new generation of insecticides shows greater affinity to invertebrate as compared to mammalian receptors, toxic effect of these compounds in vertebrates cannot be excluded. The aim of the study was to follow the course of neuronal changes in rats for 1 week after a high-dose insecticide exposure. Alterations in synaptic excitability, in sleep-wake pattern and in behavior were analyzed using conventional in vitro brain slice method, long-lasting EEG recordings, and open-field tests. The two chemicals examined in this study induced only weak and transient effects. Bensultap, acting on nicotinic acetylcholine receptors, caused a transient decrease in neuronal excitability. Sleep and behavioral changes demonstrated a similar time course. Fipronil, on the other hand, increased excitability and its effect lasted slightly longer. All effects were greatest on the first day following 'poisoning', and measured variables usually returned to normal within a week. These results suggest that the studied compounds do have some effects on the mammalian nervous system, but this effect is usually mild and temporary. PMID:16009481

  18. Physiological alterations of maximal voluntary quadriceps activation by changes of knee joint angle.

    PubMed

    Becker, R; Awiszus, F

    2001-05-01

    The purpose of this study was to investigate the influence of different angles of the knee joint on voluntary activation of the quadriceps muscle, estimating the ability of a subject to activate a muscle maximally by means of voluntary contraction. Isometric torque measurement was performed on 6 healthy subjects in 5 degrees intervals between 30 degrees and 90 degrees of knee joint flexion. Superimposed twitches at maximal voluntary contraction (MVC) and at a level of 60% and 40% of the MVC were applied and the voluntary activation estimated. At between 30 degrees and 75 degrees of knee flexion, the maximal extension torque increased at an average rate of 2.67 +/- 0.6 Nm/degree, followed by a decline with further flexion. However, throughout the joint-angle range tested, voluntary activation increased on average by 0.37%/degree with a maximum at 90 degrees of flexion. Due to the influence of joint position it is not possible to generalize results obtained at the knee joint angle of 90 degrees of flexion, which is usually used for the quadriceps twitch-interpolation technique. Consequently, it is useful to investigate voluntary activation deficits in knee joint disorders at a range of knee joint angles that includes, in particular, the more extended joint angles used frequently during daily activity.

  19. Alteration of natural (37)Ar activity concentration in the subsurface by gas transport and water infiltration.

    PubMed

    Guillon, Sophie; Sun, Yunwei; Purtschert, Roland; Raghoo, Lauren; Pili, Eric; Carrigan, Charles R

    2016-05-01

    High (37)Ar activity concentration in soil gas is proposed as a key evidence for the detection of underground nuclear explosion by the Comprehensive Nuclear Test-Ban Treaty. However, such a detection is challenged by the natural background of (37)Ar in the subsurface, mainly due to Ca activation by cosmic rays. A better understanding and improved capability to predict (37)Ar activity concentration in the subsurface and its spatial and temporal variability is thus required. A numerical model integrating (37)Ar production and transport in the subsurface is developed, including variable soil water content and water infiltration at the surface. A parameterized equation for (37)Ar production in the first 15 m below the surface is studied, taking into account the major production reactions and the moderation effect of soil water content. Using sensitivity analysis and uncertainty quantification, a realistic and comprehensive probability distribution of natural (37)Ar activity concentrations in soil gas is proposed, including the effects of water infiltration. Site location and soil composition are identified as the parameters allowing for a most effective reduction of the possible range of (37)Ar activity concentrations. The influence of soil water content on (37)Ar production is shown to be negligible to first order, while (37)Ar activity concentration in soil gas and its temporal variability appear to be strongly influenced by transient water infiltration events. These results will be used as a basis for practical CTBTO concepts of operation during an OSI.

  20. Alteration of natural (37)Ar activity concentration in the subsurface by gas transport and water infiltration.

    PubMed

    Guillon, Sophie; Sun, Yunwei; Purtschert, Roland; Raghoo, Lauren; Pili, Eric; Carrigan, Charles R

    2016-05-01

    High (37)Ar activity concentration in soil gas is proposed as a key evidence for the detection of underground nuclear explosion by the Comprehensive Nuclear Test-Ban Treaty. However, such a detection is challenged by the natural background of (37)Ar in the subsurface, mainly due to Ca activation by cosmic rays. A better understanding and improved capability to predict (37)Ar activity concentration in the subsurface and its spatial and temporal variability is thus required. A numerical model integrating (37)Ar production and transport in the subsurface is developed, including variable soil water content and water infiltration at the surface. A parameterized equation for (37)Ar production in the first 15 m below the surface is studied, taking into account the major production reactions and the moderation effect of soil water content. Using sensitivity analysis and uncertainty quantification, a realistic and comprehensive probability distribution of natural (37)Ar activity concentrations in soil gas is proposed, including the effects of water infiltration. Site location and soil composition are identified as the parameters allowing for a most effective reduction of the possible range of (37)Ar activity concentrations. The influence of soil water content on (37)Ar production is shown to be negligible to first order, while (37)Ar activity concentration in soil gas and its temporal variability appear to be strongly influenced by transient water infiltration events. These results will be used as a basis for practical CTBTO concepts of operation during an OSI. PMID:26939033

  1. Alterations in brain activation during cognitive empathy are related to social functioning in schizophrenia.

    PubMed

    Smith, Matthew J; Schroeder, Matthew P; Abram, Samantha V; Goldman, Morris B; Parrish, Todd B; Wang, Xue; Derntl, Birgit; Habel, Ute; Decety, Jean; Reilly, James L; Csernansky, John G; Breiter, Hans C

    2015-01-01

    Impaired cognitive empathy (ie, understanding the emotional experiences of others) is associated with poor social functioning in schizophrenia. However, it is unclear whether the neural activity underlying cognitive empathy relates to social functioning. This study examined the neural activation supporting cognitive empathy performance and whether empathy-related activation during correctly performed trials was associated with self-reported cognitive empathy and measures of social functioning. Thirty schizophrenia outpatients and 24 controls completed a cognitive empathy paradigm during functional magnetic resonance imaging. Neural activity corresponding to correct judgments about the expected emotional expression in a social interaction was compared in schizophrenia subjects relative to control subjects. Participants also completed a self-report measure of empathy and 2 social functioning measures (social competence and social attainment). Schizophrenia subjects demonstrated significantly lower accuracy in task performance and were characterized by hypoactivation in empathy-related frontal, temporal, and parietal regions as well as hyperactivation in occipital regions compared with control subjects during accurate cognitive empathy trials. A cluster with peak activation in the supplementary motor area (SMA) extending to the anterior midcingulate cortex (aMCC) correlated with social competence and social attainment in schizophrenia subjects but not controls. These results suggest that neural correlates of cognitive empathy may be promising targets for interventions aiming to improve social functioning and that brain activation in the SMA/aMCC region could be used as a biomarker for monitoring treatment response.

  2. Zebrafish locomotor capacity and brain acetylcholinesterase activity is altered by Aphanizomenon flos-aquae DC-1 aphantoxins.

    PubMed

    Zhang, De Lu; Hu, Chun Xiang; Li, Dun Hai; Liu, Yong Ding

    2013-08-15

    Aphanizomenon flos-aquae (A. flos-aquae) is a source of neurotoxins known as aphantoxins or paralytic shellfish poisons (PSPs) that present a major threat to the environment and to human health. Generally, altered neurological function is reflected in behavior. Although the molecular mechanism of action of PSPs is well known, its neurobehavioral effects on adult zebrafish and its relationship with altered neurological functions are poorly understood. Aphantoxins purified from a natural isolate of A. flos-aquae DC-1 were analyzed by HPLC. The major analogs found in the toxins were the gonyautoxins 1 and 5 (GTX1 and GTX5; 34.04% and 21.28%, respectively) and the neosaxitoxin (neoSTX, 12.77%). Zebrafish (Danio rerio) were intraperitoneally injected with 5.3 and 7.61 μg STXeq/kg (low and high dose, respectively) of A. flos-aquae DC-1 aphantoxins. The swimming activity was investigated by observation combined with video at 6 timepoints from 1 to 24 h post-exposure. Both aphantoxin doses were associated with delayed touch responses, reduced head-tail locomotory abilities, inflexible turning of head, and a tailward-shifted center of gravity. The normal S-pattern (or undulating) locomotor trajectory was replaced by a mechanical motor pattern of swinging the head after wagging the tail. Finally, these fish principally distributed at the top and/or bottom water of the aquarium, and showed a clear polarized distribution pattern at 12 h post-exposure. Further analysis of neurological function demonstrated that both aphantoxin doses inhibited brain acetylcholinesterase activity. All these changes were dose- and time-dependent. These results demonstrate that aphantoxins can alter locomotor capacity, touch responses and distribution patterns by damaging the cholinergic system of zebrafish, and suggest that zebrafish locomotor behavior and acetylcholinesterase can be used as indicators for investigating aphantoxins and blooms in nature. PMID:23792258

  3. ORM Expression Alters Sphingolipid Homeostasis and Differentially Affects Ceramide Synthase Activity1[OPEN

    PubMed Central

    Kimberlin, Athen N.; Chen, Ming; Dunn, Teresa M.

    2016-01-01

    Sphingolipid synthesis is tightly regulated in eukaryotes. This regulation in plants ensures sufficient sphingolipids to support growth while limiting the accumulation of sphingolipid metabolites that induce programmed cell death. Serine palmitoyltransferase (SPT) catalyzes the first step in sphingolipid biosynthesis and is considered the primary sphingolipid homeostatic regulatory point. In this report, Arabidopsis (Arabidopsis thaliana) putative SPT regulatory proteins, orosomucoid-like proteins AtORM1 and AtORM2, were found to interact physically with Arabidopsis SPT and to suppress SPT activity when coexpressed with Arabidopsis SPT subunits long-chain base1 (LCB1) and LCB2 and the small subunit of SPT in a yeast (Saccharomyces cerevisiae) SPT-deficient mutant. Consistent with a role in SPT suppression, AtORM1 and AtORM2 overexpression lines displayed increased resistance to the programmed cell death-inducing mycotoxin fumonisin B1, with an accompanying reduced accumulation of LCBs and C16 fatty acid-containing ceramides relative to wild-type plants. Conversely, RNA interference (RNAi) suppression lines of AtORM1 and AtORM2 displayed increased sensitivity to fumonisin B1 and an accompanying strong increase in LCBs and C16 fatty acid-containing ceramides relative to wild-type plants. Overexpression lines also were found to have reduced activity of the class I ceramide synthase that uses C16 fatty acid acyl-coenzyme A and dihydroxy LCB substrates but increased activity of class II ceramide synthases that use very-long-chain fatty acyl-coenzyme A and trihydroxy LCB substrates. RNAi suppression lines, in contrast, displayed increased class I ceramide synthase activity but reduced class II ceramide synthase activity. These findings indicate that ORM mediation of SPT activity differentially regulates functionally distinct ceramide synthase activities as part of a broader sphingolipid homeostatic regulatory network. PMID:27506241

  4. Prenatal drug exposure to illicit drugs alters working memory-related brain activity and underlying network properties in adolescence.

    PubMed

    Schweitzer, Julie B; Riggins, Tracy; Liang, Xia; Gallen, Courtney; Kurup, Pradeep K; Ross, Thomas J; Black, Maureen M; Nair, Prasanna; Salmeron, Betty Jo

    2015-01-01

    The persistence of effects of prenatal drug exposure (PDE) on brain functioning during adolescence is poorly understood. We explored neural activation to a visuospatial working memory (VSWM) versus a control task using functional magnetic resonance imaging (fMRI) in adolescents with PDE and a community comparison group (CC) of non-exposed adolescents. We applied graph theory metrics to resting state data using a network of nodes derived from the VSWM task activation map to further explore connectivity underlying WM functioning. Participants (ages 12-15 years) included 47 adolescents (27 PDE and 20 CC). All analyses controlled for potentially confounding differences in birth characteristics and postnatal environment. Significant group by task differences in brain