WorldWideScience

Sample records for hydrocarbon receptor suppresses

  1. Tissue distribution of aryl hydrocarbon receptor in the intestine: Implication of putative roles in tumor suppression

    Energy Technology Data Exchange (ETDEWEB)

    Ikuta, Togo, E-mail: togo@cancer-c.pref.saitama.jp [Department of Cancer Prevention, Research Institute for Clinical Oncology, Saitama Cancer Center, 818 Komuro, Ina-machi, Kitaadachi-gun, Saitama 362-0806 (Japan); Kurosumi, Masafumi, E-mail: mkurosumi@cancer-c.pref.saitama.jp [Division of Pathology, Saitama Cancer Center, 780 Komuro, Ina-machi, Kitaadachi-gun, Saitama 362-0806 (Japan); Yatsuoka, Toshimasa, E-mail: yatsuoka-gi@umin.ac.jp [Division of Gastroenterological Surgery, Saitama Cancer Center, 780 Komuro, Ina-machi, Kitaadachi-gun, Saitama 362-0806 (Japan); Nishimura, Yoji, E-mail: yojinish@cancr-c.pref.saitama.jp [Division of Gastroenterological Surgery, Saitama Cancer Center, 780 Komuro, Ina-machi, Kitaadachi-gun, Saitama 362-0806 (Japan)

    2016-05-01

    Intestinal homeostasis is maintained by complex interactions between intestinal microorganisms and the gut immune system. Dysregulation of gut immunity may lead to inflammatory disorders and tumorigenesis. We previously have shown the tumor suppressive effects of aryl hydrocarbon receptor (AhR) in intestinal carcinogenesis. In the present study, we investigated AhR distribution in the mouse and human intestine by histochemical analysis. In the normal intestine, AhR was mainly localized in the stroma containing immune cells in the lamina propria and lymphoid follicles. On the other hand, in the tumor tissue from human colon cancer and that developed in Apc{sup Min/+}mice, AhR expression was elevated. AhR immunostaining was found in both stromal and tumor cells. Although AhR was localized in the cytoplasm of tumor cells in most cases, nuclear AhR was also observed in some. AhR knockdown using siRNA resulted in significant promotion of cell growth in colon cancer cell lines. Furthermore, AhR activation by AhR ligands supplemented in culture medium suppressed cell growth. Our study results suggest that tumor suppressive roles of AhR are estimated in two distinct ways: in normal tissue, AhR is associated with tumor prevention by regulating gut immunity, whereas in tumor cells, it is involved in growth suppression. - Highlights: • In the normal intestine, AhR was mainly localized in stroma containing immune cells. • In the tumor tissue, AhR expression was found in both stromal and tumor cells. • AhR knockdown promoted cell growth in colon cancer cell lines.

  2. Aryl hydrocarbon receptor regulates histone deacetylase 8 expression to repress tumor suppressive activity in hepatocellular carcinoma.

    Science.gov (United States)

    Wang, Li-Ting; Chiou, Shyh-Shin; Chai, Chee-Yin; Hsi, Edward; Wang, Shen-Nien; Huang, Shau-Ku; Hsu, Shih-Hsien

    2017-01-31

    Histone deacetylase 8 (HDAC8), a unique member of class I histone deacetylases, shows remarkable correlation with advanced disease stage and multiple malignant tumors However, little is known about the contribution of HDAC8 to the tumorigenesis of hepatocellular carcinoma (HCC). The present study investigated the expression of HDAC8 regulated by the aryl hydrocarbon receptor (AHR) in HCC cell lines and tissues, and the roles of HDAC8 overexpression in cell proliferation, including potentially underlying mechanisms. We assessed the correlation between the clinic-pathological parameters and the expression of AHR and HDAC8. Further, we analyzed the AHR siRNA transfection and HDAC8 inhibitors to explore the functions of HDAC8 in HCC progression in vitro and in vivo. In a panel of 289 HCC patients, HDAC8 was shown to be highly correlated with AHR expression at both mRNA and protein levels. HCC patients with high AHR expression showed a shorter survival time than that with low AHR expression. We then found that the expression of both AHR and HDAC8 was significantly upregulated in both HCC cell lines and tumor tissues compared to human normal hepatocytes and matched non-tumor tissues. Furthermore, HDAC8 inhibition remarkably inhibited hepatoma cell proliferation and transformation activity via upregulation of RB1 in vitro and in vivo. Our data revealed an important role of the AHR-HDAC8 axis in promoting HCC tumorigenesis, thus identifying HDAC8 as a potential therapeutic target for HCC treatment.

  3. PCB 126 and other dioxin-like PCBs specifically suppress hepatic PEPCK expression via the aryl hydrocarbon receptor.

    Science.gov (United States)

    Zhang, Wenshuo; Sargis, Robert M; Volden, Paul A; Carmean, Christopher M; Sun, Xiao J; Brady, Matthew J

    2012-01-01

    Dioxins and dioxin-like compounds encompass a group of structurally related heterocyclic compounds that bind to and activate the aryl hydrocarbon receptor (AhR). The prototypical dioxin is 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), a highly toxic industrial byproduct that incites numerous adverse physiological effects. Global commercial production of the structurally similar polychlorinated biphenyls (PCBs), however, commenced early in the 20(th) century and continued for decades; dioxin-like PCBs therefore contribute significantly to total dioxin-associated toxicity. In this study, PCB 126, the most potent dioxin-like PCB, was evaluated with respect to its direct effects on hepatic glucose metabolism using primary mouse hepatocytes. Overnight treatment with PCB 126 reduced hepatic glycogen stores in a dose-dependent manner. Additionally, PCB 126 suppressed forskolin-stimulated gluconeogenesis from lactate. These effects were independent of acute toxicity, as PCB 126 did not increase lactate dehydrogenase release nor affect lipid metabolism or total intracellular ATP. Interestingly, provision of cells with glycerol instead of lactate as the carbon source completely restored hepatic glucose production, indicating specific impairment in the distal arm of gluconeogenesis. In concordance with this finding, PCB 126 blunted the forskolin-stimulated increase in phosphoenolpyruvate carboxykinase (PEPCK) mRNA levels without affecting glucose-6-phosphatase expression. Myricetin, a putative competitive AhR antagonist, reversed the suppression of PEPCK induction by PCB 126. Furthermore, other dioxin-like PCBs demonstrated similar effects on PEPCK expression in parallel with their ability to activate AhR. It therefore appears that AhR activation mediates the suppression of PEPCK expression by dioxin-like PCBs, suggesting a role for these pollutants as disruptors of energy metabolism.

  4. PCB 126 and other dioxin-like PCBs specifically suppress hepatic PEPCK expression via the aryl hydrocarbon receptor.

    Directory of Open Access Journals (Sweden)

    Wenshuo Zhang

    Full Text Available Dioxins and dioxin-like compounds encompass a group of structurally related heterocyclic compounds that bind to and activate the aryl hydrocarbon receptor (AhR. The prototypical dioxin is 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD, a highly toxic industrial byproduct that incites numerous adverse physiological effects. Global commercial production of the structurally similar polychlorinated biphenyls (PCBs, however, commenced early in the 20(th century and continued for decades; dioxin-like PCBs therefore contribute significantly to total dioxin-associated toxicity. In this study, PCB 126, the most potent dioxin-like PCB, was evaluated with respect to its direct effects on hepatic glucose metabolism using primary mouse hepatocytes. Overnight treatment with PCB 126 reduced hepatic glycogen stores in a dose-dependent manner. Additionally, PCB 126 suppressed forskolin-stimulated gluconeogenesis from lactate. These effects were independent of acute toxicity, as PCB 126 did not increase lactate dehydrogenase release nor affect lipid metabolism or total intracellular ATP. Interestingly, provision of cells with glycerol instead of lactate as the carbon source completely restored hepatic glucose production, indicating specific impairment in the distal arm of gluconeogenesis. In concordance with this finding, PCB 126 blunted the forskolin-stimulated increase in phosphoenolpyruvate carboxykinase (PEPCK mRNA levels without affecting glucose-6-phosphatase expression. Myricetin, a putative competitive AhR antagonist, reversed the suppression of PEPCK induction by PCB 126. Furthermore, other dioxin-like PCBs demonstrated similar effects on PEPCK expression in parallel with their ability to activate AhR. It therefore appears that AhR activation mediates the suppression of PEPCK expression by dioxin-like PCBs, suggesting a role for these pollutants as disruptors of energy metabolism.

  5. PCB 126 and Other Dioxin-Like PCBs Specifically Suppress Hepatic PEPCK Expression via the Aryl Hydrocarbon Receptor

    Science.gov (United States)

    Zhang, Wenshuo; Sargis, Robert M.; Volden, Paul A.; Carmean, Christopher M.; Sun, Xiao J.; Brady, Matthew J.

    2012-01-01

    Dioxins and dioxin-like compounds encompass a group of structurally related heterocyclic compounds that bind to and activate the aryl hydrocarbon receptor (AhR). The prototypical dioxin is 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), a highly toxic industrial byproduct that incites numerous adverse physiological effects. Global commercial production of the structurally similar polychlorinated biphenyls (PCBs), however, commenced early in the 20th century and continued for decades; dioxin-like PCBs therefore contribute significantly to total dioxin-associated toxicity. In this study, PCB 126, the most potent dioxin-like PCB, was evaluated with respect to its direct effects on hepatic glucose metabolism using primary mouse hepatocytes. Overnight treatment with PCB 126 reduced hepatic glycogen stores in a dose-dependent manner. Additionally, PCB 126 suppressed forskolin-stimulated gluconeogenesis from lactate. These effects were independent of acute toxicity, as PCB 126 did not increase lactate dehydrogenase release nor affect lipid metabolism or total intracellular ATP. Interestingly, provision of cells with glycerol instead of lactate as the carbon source completely restored hepatic glucose production, indicating specific impairment in the distal arm of gluconeogenesis. In concordance with this finding, PCB 126 blunted the forskolin-stimulated increase in phosphoenolpyruvate carboxykinase (PEPCK) mRNA levels without affecting glucose-6-phosphatase expression. Myricetin, a putative competitive AhR antagonist, reversed the suppression of PEPCK induction by PCB 126. Furthermore, other dioxin-like PCBs demonstrated similar effects on PEPCK expression in parallel with their ability to activate AhR. It therefore appears that AhR activation mediates the suppression of PEPCK expression by dioxin-like PCBs, suggesting a role for these pollutants as disruptors of energy metabolism. PMID:22615911

  6. Aryl hydrocarbon receptor (AhR agonists suppress interleukin-6 expression by bone marrow stromal cells: an immunotoxicology study

    Directory of Open Access Journals (Sweden)

    Schlezinger Jennifer J

    2003-12-01

    Full Text Available Abstract Background Bone marrow stromal cells produce cytokines required for the normal growth and development of all eight hematopoietic cell lineages. Aberrant cytokine production by stromal cells contributes to blood cell dyscrasias. Consequently, factors that alter stromal cell cytokine production may significantly compromise the development of normal blood cells. We have shown that environmental chemicals, such as aromatic hydrocarbon receptor (AhR agonists, suppress B lymphopoiesis by modulating bone marrow stromal cell function. Here, we extend these studies to evaluate the potential for two prototypic AhR agonists, 7,12-dimethylbenz [a]anthracene (DMBA and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD, to alter stromal cell cytokine responses. Methods Bone marrow stromal cells were treated with AhR agonists and bacterial lipopolysaccharide (LPS to mimic innate inflammatory cytokine responses and to study the effects of AhR ligands on those responses. Steady state cytokine RNA levels were screened by RNAse protection assays (RPA and quantified by real-time PCR. Cytokine (IL-6 protein production was measured by ELISA. NF-κB EMSAs were used to study IL-6 transcriptional regulation. Results RPAs indicated that AhR+ bone marrow stromal cells consistently up-regulated genes encoding IL-6 and LIF in response to LPS, presumably through activation of Toll-like receptor 4. Pre-treatment with low doses of DMBA or TCDD selectively abrogated IL-6 gene induction but had no effect on LIF mRNA. Real-time-PCR indicated a significant inhibition of IL-6 mRNA by AhR ligands within 1 hour of LPS challenge which was reflected in a profound down-regulation of IL-6 protein induction, with DMBA and TCDD suppressing IL-6 levels as much as 65% and 88%, respectively. This potent inhibitory effect persisted for at least 72 hours. EMSAs measuring NF-κB binding to IL-6 promoter sequences, an event known to induce IL-6 transcription, indicated a significant decrease in

  7. Aryl hydrocarbon receptor suppresses the osteogenesis of mesenchymal stem cells in collagen-induced arthritic mice through the inhibition of β-catenin

    Energy Technology Data Exchange (ETDEWEB)

    Tong, Yulong [Department of Immunology, School of Basic Medical Sciences, Capital Medical University, No. 10 Xitoutiao, You An Men, Beijing 100069 (China); Niu, Menglin [Department of Immunology, School of Basic Medical Sciences, Capital Medical University, No. 10 Xitoutiao, You An Men, Beijing 100069 (China); Department of Blood Transfusion, Peking University Cancer Hospital & Institute, No. 52 Fucheng Rd., Beijing 100142 (China); Du, Yuxuan; Mei, Wentong; Cao, Wei; Dou, Yunpeng [Department of Immunology, School of Basic Medical Sciences, Capital Medical University, No. 10 Xitoutiao, You An Men, Beijing 100069 (China); Yu, Haitao [Department of Clinical Laboratory, The First Hospital of Lanzhou University, Lanzhou, Gansu Province 730000 (China); Du, Xiaonan [Department of Immunology, School of Basic Medical Sciences, Capital Medical University, No. 10 Xitoutiao, You An Men, Beijing 100069 (China); Yuan, Huihui, E-mail: huihui_yuan@163.com [Department of Immunology, School of Basic Medical Sciences, Capital Medical University, No. 10 Xitoutiao, You An Men, Beijing 100069 (China); Zhao, Wenming, E-mail: zhao-wenming@163.com [Department of Immunology, School of Basic Medical Sciences, Capital Medical University, No. 10 Xitoutiao, You An Men, Beijing 100069 (China)

    2017-01-15

    The contributions of aryl hydrocarbon receptor (Ahr) to the pathogenesis of rheumatoid arthritis (RA), particularly bone loss, have not been clearly explored. The imbalance between osteoblasts and osteoclasts is a major reason for bone loss. The dysfunction of osteoblasts, which are derived from mesenchymal stem cells (MSCs), induced bone erosion occurs earlier and is characterized as more insidious. Here, we showed that the nuclear expression and translocation of Ahr were both significantly increased in MSCs from collagen-induced arthritis (CIA) mice. The enhanced Ahr suppressed the mRNA levels of osteoblastic markers including Alkaline phosphatase (Alp) and Runt-related transcription factor 2 (Runx2) in the differentiation of MSCs to osteoblasts in CIA. The 2, 3, 7, 8-tetrachlorodibenzo-p-dioxin (TCDD)-mediated activation of Ahr dose-dependently suppressed the expression of osteoblastic markers. In addition, the expression of β-catenin was reduced in CIA MSCs compared with control, and the TCDD-mediated activation of the Ahr significantly inhibited β-catenin expression. The Wnt3a-induced the activation of Wnt/β-catenin pathway partly rescued the osteogenesis decline induced by TCDD. Taken together, these results indicate that activated Ahr plays a negative role in CIA MSCs osteogenesis, possibly by suppressing the expression of β-catenin. - Highlights: • The Ahr pathway displays an activated profile in CIA MSCs. • The activation of Ahr suppresses osteogenesis in CIA MSCs. • TCDD suppresses osteogenesis in a dose-dependent manner. • The activation of Ahr inhibits β-catenin expression to exacerbate bone erosion.

  8. Metformin suppresses CYP1A1 and CYP1B1 expression in breast cancer cells by down-regulating aryl hydrocarbon receptor expression

    Energy Technology Data Exchange (ETDEWEB)

    Do, Minh Truong; Kim, Hyung Gyun; Tran, Thi Thu Phuong; Khanal, Tilak; Choi, Jae Ho [Department of Toxicology, College of Pharmacy, Chungnam National University, Daejeon (Korea, Republic of); Chung, Young Chul [Department of Food Science and Culinary, International University of Korea, Jinju (Korea, Republic of); Jeong, Tae Cheon, E-mail: taecheon@ynu.ac.kr [College of Pharmacy, Yeungnam University, Gyeongsan (Korea, Republic of); Jeong, Hye Gwang, E-mail: hgjeong@cnu.ac.kr [Department of Toxicology, College of Pharmacy, Chungnam National University, Daejeon (Korea, Republic of)

    2014-10-01

    Induction of cytochrome P450 (CYP) 1A1 and CYP1B1 by environmental xenobiotic chemicals or endogenous ligands through the activation of the aryl hydrocarbon receptor (AhR) has been implicated in a variety of cellular processes related to cancer, such as transformation and tumorigenesis. Here, we investigated the effects of the anti-diabetes drug metformin on expression of CYP1A1 and CYP1B1 in breast cancer cells under constitutive and inducible conditions. Our results indicated that metformin down-regulated the expression of CYP1A1 and CYP1B1 in breast cancer cells under constitutive and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-induced conditions. Down-regulation of AhR expression was required for metformin-mediated decreases in CYP1A1 and CYP1B1 expression, and the metformin-mediated CYP1A1 and CYP1B1 reduction is irrelevant to estrogen receptor α (ERα) signaling. Furthermore, we found that metformin markedly down-regulated Sp1 protein levels in breast cancer cells. The use of genetic and pharmacological tools revealed that metformin-mediated down-regulation of AhR expression was mediated through the reduction of Sp1 protein. Metformin inhibited endogenous AhR ligand-induced CYP1A1 and CYP1B1 expression by suppressing tryptophan-2,3-dioxygenase (TDO) expression in MCF-7 cells. Finally, metformin inhibits TDO expression through a down-regulation of Sp1 and glucocorticoid receptor (GR) protein levels. Our findings demonstrate that metformin reduces CYP1A1 and CYP1B1 expression in breast cancer cells by down-regulating AhR signaling. Metformin would be able to act as a potential chemopreventive agent against CYP1A1 and CYP1B1-mediated carcinogenesis and development of cancer. - Graphical abstract: Schematic of the CYP1A1 and CYP1B1 gene regulation by metformin. - Highlights: • Metformin inhibits CYP1A1 and CYP1B1 expression. • Metformin down-regulates the AhR signaling. • Metformin reduces Sp1 protein expression. • Metformin suppresses TDO expression.

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

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Haitao; Du, Yuxuan; Zhang, Xulong; Sun, Ying; Li, Shentao; Dou, Yunpeng [Department of Immunology, School of Basic Medical Sciences, Capital Medical University, No. 10 Xitoutiao, You An Men, Beijing 100069 (China); Li, Zhanguo [Department of Rheumatology and Immunology, Clinical Immunology Center, Peking University People' s Hospital, No. 11 Xizhimen South Street, Beijing 100044 (China); Yuan, Huihui, E-mail: huihui_yuan@163.com [Department of Immunology, School of Basic Medical Sciences, Capital Medical University, No. 10 Xitoutiao, You An Men, Beijing 100069 (China); Zhao, Wenming, E-mail: zhao-wenming@163.com [Department of Immunology, School of Basic Medical Sciences, Capital Medical University, No. 10 Xitoutiao, You An Men, Beijing 100069 (China)

    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.

  10. Aryl Hydrocarbon Receptor Suppresses the Prostate Cancer LNCaP Cell Growth and Invasion by Promoting DNA Damage Response Under Oxidative Stress.

    Science.gov (United States)

    Yu, Jing-Song; Leng, Peng-Fei; Li, Yi-Fu; Wang, Yong-Quan; Wang, Yan; An, Rui-Hua; Qi, Ji-Ping

    2017-11-01

    Aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor that interacts with multiple signaling pathways during prostate development. In the present study, LNCaP cells were knocked down of AhR by siRNA, or treated with the AhR agonist 3-methylcholanthrene (3MC). The effects of AhR on LNCaP cells and the associated mechanisms were studied both under normal condition and under hydrogen peroxide (H 2 O 2 ) - induced oxidative stress. MTT, transwell chamber assays and flow cytometry were employed to investigate cell proliferation, invasion, and apoptosis, respectively, whereas the DNA damage response (DDR) signaling (phosphorylation of ataxia-telangiectasia mutated [ATM], check-point kinase 2 [Chk2], histone H2AX, p53, and cleaved poly-ADP-ribose polymerase [PARP]) was detected by western blotting. Exposure of LNCaP cells to H 2 O 2 inhibited their viability and migration, and induced apoptosis, at a greater extent compared with the culture under normal conditions. In addition, the oxidative stress increased p-ATM, p-Chk2, p-p53, and p-H2AX expression levels significantly. Knockdown of AhR attenuated the aforementioned effects caused by H 2 O 2 -induced oxidative stress. Activation of AhR by 3MC treatment, further aggravated these changes of LNCaP cells on oxidative stress. The findings indicated that AhR suppresses the viability and migration of LNCaP cells notably under oxidative stress, and this process is associated with positive regulation of the responses to oxidative DNA damage.

  11. Antioxidant Functions of the Aryl Hydrocarbon Receptor

    Directory of Open Access Journals (Sweden)

    Cornelia Dietrich

    2016-01-01

    Full Text Available The aryl hydrocarbon receptor (AhR is a transcription factor belonging to the basic helix-loop-helix/PER-ARNT-SIM family. It is activated by a variety of ligands, such as environmental contaminants like polycyclic aromatic hydrocarbons or dioxins, but also by naturally occurring compounds and endogenous ligands. Binding of the ligand leads to dimerization of the AhR with aryl hydrocarbon receptor nuclear translocator (ARNT and transcriptional activation of several xenobiotic phase I and phase II metabolizing enzymes. It is generally accepted that the toxic responses of polycyclic aromatic hydrocarbons, dioxins, and structurally related compounds are mediated by activation of the AhR. A multitude of studies indicate that the AhR operates beyond xenobiotic metabolism and exerts pleiotropic functions. Increasing evidence points to a protective role of the AhR against carcinogenesis and oxidative stress. Herein, I will highlight data demonstrating a causal role of the AhR in the antioxidant response and present novel findings on potential AhR-mediated antioxidative mechanisms.

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

    Energy Technology Data Exchange (ETDEWEB)

    Sato, Shoko, E-mail: satosho@rs.tus.ac.jp [Laboratory of Nutrition, Graduate School of Agricultural Science, Tohoku University, Sendai 981-8555 (Japan); Shirakawa, Hitoshi, E-mail: shirakah@m.tohoku.ac.jp [Laboratory of Nutrition, Graduate School of Agricultural Science, Tohoku University, Sendai 981-8555 (Japan); Tomita, Shuhei, E-mail: tomita@med.tottori-u.ac.jp [Division of Molecular Pharmacology, Department of Pathophysiological and Therapeutic Science, Yonago 683-8503 (Japan); Tohkin, Masahiro, E-mail: tohkin@phar.nagoya-cu.ac.jp [Department of Medical Safety Science, Graduate School of Pharmaceutical Science, Nagoya City University, Nagoya 267-8603 (Japan); Gonzalez, Frank J., E-mail: gonzalef@mail.nih.gov [Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892 (United States); Komai, Michio, E-mail: mkomai@m.tohoku.ac.jp [Laboratory of Nutrition, Graduate School of Agricultural Science, Tohoku University, Sendai 981-8555 (Japan)

    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. Hydrocarbon molar water solubility predicts NMDA vs. GABAA receptor modulation.

    Science.gov (United States)

    Brosnan, Robert J; Pham, Trung L

    2014-11-19

    Many anesthetics modulate 3-transmembrane (such as NMDA) and 4-transmembrane (such as GABAA) receptors. Clinical and experimental anesthetics exhibiting receptor family specificity often have low water solubility. We hypothesized that the molar water solubility of a hydrocarbon could be used to predict receptor modulation in vitro. GABAA (α1β2γ2s) or NMDA (NR1/NR2A) receptors were expressed in oocytes and studied using standard two-electrode voltage clamp techniques. Hydrocarbons from 14 different organic functional groups were studied at saturated concentrations, and compounds within each group differed only by the carbon number at the ω-position or within a saturated ring. An effect on GABAA or NMDA receptors was defined as a 10% or greater reversible current change from baseline that was statistically different from zero. Hydrocarbon moieties potentiated GABAA and inhibited NMDA receptor currents with at least some members from each functional group modulating both receptor types. A water solubility cut-off for NMDA receptors occurred at 1.1 mM with a 95% CI = 0.45 to 2.8 mM. NMDA receptor cut-off effects were not well correlated with hydrocarbon chain length or molecular volume. No cut-off was observed for GABAA receptors within the solubility range of hydrocarbons studied. Hydrocarbon modulation of NMDA receptor function exhibits a molar water solubility cut-off. Differences between unrelated receptor cut-off values suggest that the number, affinity, or efficacy of protein-hydrocarbon interactions at these sites likely differ.

  14. Specialized odorant receptors in social insects that detect cuticular hydrocarbon cues and candidate pheromones.

    Science.gov (United States)

    Pask, Gregory M; Slone, Jesse D; Millar, Jocelyn G; Das, Prithwiraj; Moreira, Jardel A; Zhou, Xiaofan; Bello, Jan; Berger, Shelley L; Bonasio, Roberto; Desplan, Claude; Reinberg, Danny; Liebig, Jürgen; Zwiebel, Laurence J; Ray, Anandasankar

    2017-08-17

    Eusocial insects use cuticular hydrocarbons as components of pheromones that mediate social behaviours, such as caste and nestmate recognition, and regulation of reproduction. In ants such as Harpegnathos saltator, the queen produces a pheromone which suppresses the development of workers' ovaries and if she is removed, workers can transition to a reproductive state known as gamergate. Here we functionally characterize a subfamily of odorant receptors (Ors) with a nine-exon gene structure that have undergone a massive expansion in ants and other eusocial insects. We deorphanize 22 representative members and find they can detect cuticular hydrocarbons from different ant castes, with one (HsOr263) that responds strongly to gamergate extract and a candidate queen pheromone component. After systematic testing with a diverse panel of hydrocarbons, we find that most Harpegnathos saltator Ors are narrowly tuned, suggesting that several receptors must contribute to detection and discrimination of different cuticular hydrocarbons important in mediating eusocial behaviour.Cuticular hydrocarbons (CHC) mediate the interactions between individuals in eusocial insects, but the sensory receptors for CHCs are unclear. Here the authors show that in ants such as H. saltator, the 9-exon subfamily of odorant receptors (HsOrs) responds to CHCs, and ectopic expression of HsOrs in Drosophila neurons imparts responsiveness to CHCs.

  15. Environmental polycyclic aromatic hydrocarbons affect androgen receptor activation in vitro

    DEFF Research Database (Denmark)

    Vinggaard, Anne Marie; Hnida, Christina; Larsen, John Christian

    2000-01-01

    Nine structurally different polycyclic aromatic hydrocarbons (PAHs) were tested for their ability to either agonize or antagonize the human androgen receptor (hAR) in a sensitive reporter gene assay based on CHO cells transiently cotransfected with a hAR vector and an MMTV-LUC vector. Benz...

  16. Dioxin increases the interaction between aryl hydrocarbon receptor and estrogen receptor alpha at human promoters

    DEFF Research Database (Denmark)

    Ahmed, Shaaima; Valen, Eivind; Sandelin, Albin Gustav

    2009-01-01

    Recent studies have shown that activated aryl hydrocarbon receptor (AHR) induced the recruitment of estrogen receptor- (ER ) to AHR-regulated genes and that AHR is recruited to ER -regulated genes. However, these findings were limited to a small number of well-characterized AHR- or ER -responsive...... regions bound by both AHR and ER . Conventional and sequential ChIPs confirmed the recruitment of AHR and ER to many of the identified regions. Transcription factor binding site analysis revealed an overrepresentation of aryl hydrocarbon receptor response elements in regions bound by both AHR and ER...

  17. Airborne polycyclic aromatic hydrocarbons trigger human skin cells aging through aryl hydrocarbon receptor.

    Science.gov (United States)

    Qiao, Yuan; Li, Qiang; Du, Hong-Yang; Wang, Qiao-Wei; Huang, Ye; Liu, Wei

    2017-07-01

    Accumulating evidence suggests that polycyclic aromatic hydrocarbons (PAH) which adsorbed on the surface of ambient air particulate matters (PM), are the major toxic compound to cause cardiovascular and respiratory diseases, even cancer. However, its detrimental effects on human skin cell remain unclear. Here, we demonstrated that SRM1649b, a reference urban dust material of PAH, triggers human skin cells aging through cell cycle arrest, cell growth inhibition and apoptosis. Principally, SRM1649b facilitated Aryl hydrocarbon receptor (AhR) translocated into nucleus, subsequently activated ERK/MAPK signaling pathway, and upregulated aging-related genes expression. Most important, we found that AhR antagonist efficiently revert the aging of skin cells. Thus our novel findings firstly revealed the mechanism of skin aging under PAH contamination and provided potential strategy for clinical application. Copyright © 2017. Published by Elsevier Inc.

  18. Activation of the Aryl Hydrocarbon Receptor Interferes with Early Embryonic Development

    Directory of Open Access Journals (Sweden)

    Manolis Gialitakis

    2017-11-01

    Full Text Available The transcriptional program of early embryonic development is tightly regulated by a set of well-defined transcription factors that suppress premature expression of differentiation genes and sustain the pluripotent identity. It is generally accepted that this program can be perturbed by environmental factors such as chemical pollutants; however, the precise molecular mechanisms remain unknown. The aryl hydrocarbon receptor (AHR is a widely expressed nuclear receptor that senses environmental stimuli and modulates target gene expression. Here, we have investigated the AHR interactome in embryonic stem cells by mass spectrometry and show that ectopic activation of AHR during early differentiation disrupts the differentiation program via the chromatin remodeling complex NuRD (nucleosome remodeling and deacetylation. The activated AHR/NuRD complex altered the expression of differentiation-specific genes that control the first two developmental decisions without affecting the pluripotency program. These findings identify a mechanism that allows environmental stimuli to disrupt embryonic development through AHR signaling.

  19. Role of the Aryl Hydrocarbon Receptor in Colon Neoplasia

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Guofeng, E-mail: gxie@medicine.umaryland.edu; Raufman, Jean-Pierre [Division of Gastroenterology and Hepatology, Veterans Administration Maryland Health Care System, University of Maryland School of Medicine, Baltimore, MD 21201 (United States)

    2015-07-31

    For both men and women, colorectal cancer (CRC) is the second leading cause of cancer death in the United States, primarily as a consequence of limited therapies for metastatic disease. The aryl hydrocarbon receptor (AhR) is a ligand-dependent transcription factor with diverse functions in detoxification of xenobiotics, inflammatory responses, and tissue homeostasis. Emerging evidence indicates that AhR also plays an important role in regulating intestinal cell proliferation and tumorigenesis. Here, we review both the pro- and anti-carcinogenic properties of AhR signaling and its potential role as a therapeutic target in CRC.

  20. The aryl hydrocarbon receptor: multitasking in the immune system.

    Science.gov (United States)

    Stockinger, Brigitta; Di Meglio, Paola; Gialitakis, Manolis; Duarte, João H

    2014-01-01

    The aryl hydrocarbon receptor (AhR), for many years almost exclusively studied by the pharmacology/toxicology field for its role in mediating the toxicity of xenobiotics such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), has more recently attracted the attention of immunologists. The evolutionary conservation of this transcription factor and its widespread expression in the immune system point to important physiological functions that are slowly being unraveled. In particular, the emphasis is now shifting from the role of AhR in the xenobiotic pathway toward its mode of action in response to physiological ligands. In this article, we review the current understanding of the molecular interactions and functions of AhR in the immune system in steady state and in the presence of infection and inflammation, with a focus on barrier organs such as the skin, the gut, and the lung.

  1. Cyprodinil as an activator of aryl hydrocarbon receptor.

    Science.gov (United States)

    Fang, Chien-Chung; Chen, Fei-Yun; Chen, Chang-Rong; Liu, Chien-Chiang; Wong, Liang-Chi; Liu, Yi-Wen; Su, Jyan-Gwo Joseph

    2013-02-08

    Cyprodinil is a pyrimidinamine fungicide, used worldwide by agriculture. It is used to protect fruit plants and vegetables from a wide range of pathogens. Benzo[a]pyrene (BaP) and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) are toxic environmental pollutants and are prototypes of aryl hydrocarbon receptor (AHR) ligands. Although the structure of cyprodinil distinctly differs from those of BaP and TCDD, our results show that cyprodinil induced nuclear translocation of the AHR, and induced the transcriptional activity of aryl hydrocarbon response element (AHRE). Cyprodinil induced the expression of cytochrome P450 (CYP) 1A1, a well-known AHR-targeted gene, in ovarian granulosa cells, HO23, and hepatoma cells, Hepa-1c1c7. Its induction did not appear in AHR signal-deficient cells, and was blocked by the AHR antagonist, CH-223191. Cyprodinil decreased AHR expression in HO23 cells, resulting in CYP1A1 expression decreasing after it peaked at 9h of treatment in HO23 cells. Dexamethasone is a synthetic agonist of glucocorticoids. Cyprodinil enhanced dexamethasone-induced gene expression, and conversely, its induction of CYP1A1 expression was decreased by dexamethasone in HO23 cells, indicating its induction of crosstalk between the AHR and glucocorticoid receptor and its role as a potential endocrine disrupter. In addition to BaP, TCDD, and an AHR agonist, β-NF, cyprodinil also phosphorylated extracellular signal-regulated kinase (ERK) in HO23 and Hepa-1c1c7 cells, indicating its deregulation of ERK activity. In summary, our results demonstrate that cyprodinil, similar to BaP, acts as an AHR activator, a potential endocrine disrupter, and an ERK disrupter. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  2. Enantiospecific effects of ketoconazole on aryl hydrocarbon receptor.

    Directory of Open Access Journals (Sweden)

    Aneta Novotna

    Full Text Available Azole antifungal ketoconazole (KET was demonstrated to activate aryl hydrocarbon receptor (AhR. Since clinically used KET is a racemic mixture of two cis-enantiomers (2R,4S-(+-KET and (2S,4R-(--KET, we examined the effects of KET enantiomers on AhR signaling pathway. (+-KET dose-dependently activated AhR in human gene reporter cell line AZ-AHR, and displayed 5-20× higher agonist activity (efficacy, as compared to (--KET; both enantiomers were AhR antagonists with equal potency (IC50. Consistently, (+-KET strongly induced CYP1A1 mRNA and protein in human HepG2 cells, while (--KET exerted less than 10% of (+-KET activity. In primary human hepatocytes, both enantiomers preferentially induced CYP1A2 over CYP1A1 mRNA and protein, and the potency of (+-KET was slightly higher as compared to (--KET. Ligand binding assay with guinea pig liver cytosols revealed that both (+-KET and (--KET are weak ligands of AhR that displaced [3H]-TCDD with comparable potency. Similarly, both enantiomers weakly transformed AhR to DNA-binding form with similar potency, as showed by EMSA, in guinea pig liver cytosolic extracts and nuclear extracts from mouse Hepa-1 cells. We also examined effects of KET on glucocorticoid receptor (GR, a regulator of AhR activity. Both KET enantiomers antagonized GR with similar potency, as revealed by gene reporter assay in AZ-GR cell line and down-regulation of tyrosine aminotransferase mRNA in human hepatocytes. Finally, we demonstrate enantiospecific antifungal activities of KET enantiomers in six Candida spp. strains. In conclusion, the significance of current study is providing the first evidence of enatiospecific effects of cis-enantiomers of ketoconazole on AhR-CYP1A pathway.

  3. Regulation of Innate Lymphoid Cells by Aryl Hydrocarbon Receptor

    Directory of Open Access Journals (Sweden)

    Shiyang Li

    2018-01-01

    Full Text Available With striking similarity to their adaptive T helper cell counterparts, innate lymphoid cells (ILCs represent an emerging family of cell types that express signature transcription factors, including T-bet+ Eomes+ natural killer cells, T-bet+ Eomes− group 1 ILCs, GATA3+ group 2 ILCs, RORγt+ group 3 ILCs, and newly identified Id3+ regulatory ILC. ILCs are abundantly present in barrier tissues of the host (e.g., the lung, gut, and skin at the interface of host–environment interactions. Active research has been conducted to elucidate molecular mechanisms underlying the development and function of ILCs. The aryl hydrocarbon receptor (Ahr is a ligand-dependent transcription factor, best known to mediate the effects of xenobiotic environmental toxins and endogenous microbial and dietary metabolites. Here, we review recent progresses regarding Ahr function in ILCs. We focus on the Ahr-mediated cross talk between ILCs and other immune/non-immune cells in host tissues especially in the gut. We discuss the molecular mechanisms of the action of Ahr expression and activity in regulation of ILCs in immunity and inflammation, and the interaction between Ahr and other pathways/transcription factors in ILC development and function with their implication in disease.

  4. In vitro function of the aryl hydrocarbon receptor predicts in ...

    Science.gov (United States)

    Differences in sensitivity to dioxin-like compounds (DLCs) among species and taxa presents a major challenge to ecological risk assessments. Activation of the aryl hydrocarbon receptor (AHR) regulates adverse effects associated with exposure to DLCs in vertebrates. Prior investigations demonstrated that sensitivity to activation of the AHR1 (50% effect concentration; EC50) in an in vitro luciferase reporter gene (LRG) assay was predictive of the sensitivity of embryos (lethal dose to cause 50% lethality; LD50) across all species of birds for all DLCs. However, nothing was known about whether sensitivity to activation of the AHR is predictive of sensitivity of embryos of fishes to DLCs. Therefore, this study investigated in vitro sensitivities of AHR1s and AHR2s to the model DLC, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), among eight species of fish of known sensitivities of embryos to TCDD. AHR1s and AHR2s of all fishes were activated by TCDD in vitro. There was no significant linear relationship between in vitro sensitivity of AHR1 and in vivo sensitivity among the investigated fishes (R2 = 0.33, p = 0.23). However, there was a significant linear relationship between in vitro sensitivity of AHR2 and in vivo sensitivity among the investigated fishes (R2 = 0.97, p = vitro sensitivity of AHR2 and in vivo sensitivity of embryos among fishes was compared to the previously generated linear relationship between in vitro s

  5. Regulation of Innate Lymphoid Cells by Aryl Hydrocarbon Receptor

    Science.gov (United States)

    Li, Shiyang; Bostick, John W.; Zhou, Liang

    2018-01-01

    With striking similarity to their adaptive T helper cell counterparts, innate lymphoid cells (ILCs) represent an emerging family of cell types that express signature transcription factors, including T-bet+ Eomes+ natural killer cells, T-bet+ Eomes− group 1 ILCs, GATA3+ group 2 ILCs, RORγt+ group 3 ILCs, and newly identified Id3+ regulatory ILC. ILCs are abundantly present in barrier tissues of the host (e.g., the lung, gut, and skin) at the interface of host–environment interactions. Active research has been conducted to elucidate molecular mechanisms underlying the development and function of ILCs. The aryl hydrocarbon receptor (Ahr) is a ligand-dependent transcription factor, best known to mediate the effects of xenobiotic environmental toxins and endogenous microbial and dietary metabolites. Here, we review recent progresses regarding Ahr function in ILCs. We focus on the Ahr-mediated cross talk between ILCs and other immune/non-immune cells in host tissues especially in the gut. We discuss the molecular mechanisms of the action of Ahr expression and activity in regulation of ILCs in immunity and inflammation, and the interaction between Ahr and other pathways/transcription factors in ILC development and function with their implication in disease. PMID:29354125

  6. Toxicity of teriflunomide in aryl hydrocarbon receptor deficient mice.

    Science.gov (United States)

    Redaelli, Chiara; Gaffarogullari, Ece Cazibe; Brune, Maik; Pilz, Caroline; Becker, Simon; Sonner, Jana; Jäschke, Andres; Gröne, Hermann-Josef; Wick, Wolfgang; Platten, Michael; Lanz, Tobias Volker

    2015-12-01

    The intracellular transcription factor aryl hydrocarbon receptor (AHR) is bound and activated by xenobiotics, thereby promoting their catabolism by inducing expression of cytochrome P450 oxidase (CYP) genes through binding xenobiotic response elements (XRE) in their promoter region. In addition, it is involved in several cellular pathways like cell proliferation, differentiation, regeneration, tumor invasiveness and immune responses. Several pharmaceutical compounds like benzimidazoles activate the AHR and induce their own metabolic degradation. Using newly generated XRE-reporter mice, which allow in vivo bioluminescence imaging of AHR activation, we show here that the AHR is activated in vivo by teriflunomide (TER), which has recently been approved for the treatment of multiple sclerosis. While we did not find any evidence that the AHR mediates the immunomodulatory effects of TER, AHR activation led to metabolism and detoxification of teriflunomide, most likely via CYP. Mice deficient for the AHR show higher blood levels of teriflunomide, suffer from enhanced thrombo- and leukopenia and elevated liver enzymes as well as from severe gastrointestinal ulcers and bleeding which are lethal after 8-11 days of treatment. Leukopenia, acute liver damage and diarrhea have also been described as common side effects in human trials with TER. These data suggest that the AHR is relevant for detoxification not only of environmental toxins but also of drugs in clinical use, with potential implications for the application of AHR-modifying therapies in conjunction to TER in humans. The XRE-reporter mouse is a useful novel tool for monitoring AHR activation using in vivo imaging. Copyright © 2015 Elsevier Inc. All rights reserved.

  7. Oculomotor deficits in aryl hydrocarbon receptor null mouse.

    Directory of Open Access Journals (Sweden)

    Aline Chevallier

    Full Text Available The Aryl hydrocarbon Receptor or AhR, a ligand-activated transcription factor, is known to mediate the toxic and carcinogenic effects of various environmental pollutants such as 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD. Recent studies in Caenorhabditis elegans and Drosophila melanogaster show that the orthologs of the AhR are expressed exclusively in certain types of neurons and are implicated in the development and the homeostasis of the central nervous system. While physiological roles of the AhR were demonstrated in the mammalian heart, liver and gametogenesis, its ontogenic expression and putative neural functions remain elusive. Here, we report that the constitutive absence of the AhR in adult mice (AhR-/- leads to abnormal eye movements in the form of a spontaneous pendular horizontal nystagmus. To determine if the nystagmus is of vestibular, visual, or cerebellar origin, gaze stabilizing reflexes, namely vestibulo-ocular and optokinetic reflexes (VOR and OKR, were investigated. The OKR is less effective in the AhR-/- mice suggesting a deficit in the visuo-motor circuitry, while the VOR is mildly affected. Furthermore, the AhR is expressed in the retinal ganglion cells during the development, however electroretinograms revealed no impairment of retinal cell function. The structure of the cerebellum of the AhR-/- mice is normal which is compatible with the preserved VOR adaptation, a plastic process dependent on cerebellar integrity. Finally, intoxication with TCDD of control adults did not lead to any abnormality of the oculomotor control. These results demonstrate that the absence of the AhR leads to acquired central nervous system deficits in the adults. Given the many common features between both AhR mouse and human infantile nystagmus syndromes, the AhR-/- mice might give insights into the developmental mechanisms which lead to congenital eye disorders.

  8. Receptor Model Source Apportionment of Nonmethane Hydrocarbons in Mexico City

    Directory of Open Access Journals (Sweden)

    V. Mugica

    2002-01-01

    Full Text Available With the purpose of estimating the source contributions of nonmethane hydrocarbons (NMHC to the atmosphere at three different sites in the Mexico City Metropolitan Area, 92 ambient air samples were measured from February 23 to March 22 of 1997. Light- and heavy-duty vehicular profiles were determined to differentiate the NMHC contribution of diesel and gasoline to the atmosphere. Food cooking source profiles were also determined for chemical mass balance receptor model application. Initial source contribution estimates were carried out to determine the adequate combination of source profiles and fitting species. Ambient samples of NMHC were apportioned to motor vehicle exhaust, gasoline vapor, handling and distribution of liquefied petroleum gas (LP gas, asphalt operations, painting operations, landfills, and food cooking. Both gasoline and diesel motor vehicle exhaust were the major NMHC contributors for all sites and times, with a percentage of up to 75%. The average motor vehicle exhaust contributions increased during the day. In contrast, LP gas contribution was higher during the morning than in the afternoon. Apportionment for the most abundant individual NMHC showed that the vehicular source is the major contributor to acetylene, ethylene, pentanes, n-hexane, toluene, and xylenes, while handling and distribution of LP gas was the major source contributor to propane and butanes. Comparison between CMB estimates of NMHC and the emission inventory showed a good agreement for vehicles, handling and distribution of LP gas, and painting operations; nevertheless, emissions from diesel exhaust and asphalt operations showed differences, and the results suggest that these emissions could be underestimated.

  9. Bioassay directed identification of natural aryl hydrocarbon-receptor agonists in marmalade

    NARCIS (Netherlands)

    Ede, van K.I.; Li, A.; Antunes Fernandes, E.C.; Mulder, P.P.J.; Peijnenburg, A.A.C.M.; Hoogenboom, L.A.P.

    2008-01-01

    Citrus fruit and citrus fruit products, like grapefruit, lemon and marmalade were shown to contain aryl hydrocarbon receptor (AhR) agonists, as detected with the DR CALUX® bioassay. This is of interest regarding the role of the Ah-receptor pathway in the adverse effects of dioxins, PCBs and other

  10. Indoxyl Sulfate Downregulates Mas Receptor via Aryl Hydrocarbon Receptor/Nuclear Factor-kappa B, and Induces Cell Proliferation and Tissue Factor Expression in Vascular Smooth Muscle Cells.

    Science.gov (United States)

    Ng, Hwee-Yeong; Bolati, Wulaer; Lee, Chien-Te; Chien, Yu-Shu; Yisireyili, Maimaiti; Saito, Shinichi; Pei, Sung-Nan; Nishijima, Fuyuhiko; Niwa, Toshimitsu

    2016-01-01

    Angiotensin converting enzyme-related carboxypeptidase 2/angiotensin (Ang)-(1-7)/Mas receptor axis is protective in the development of chronic kidney disease and cardiovascular disease. This study is aimed at investigating whether indoxyl sulfate (IS) affects Mas receptor expression, cell proliferation and tissue factor expression in vascular smooth muscle cells, and if Ang-(1-7), an activator of Mas receptor, counteracts the IS-induced effects. IS was administered to normotensive and hypertensive rats. Human aortic smooth muscle cells (HASMCs) were cultured with IS. IS reduced the expression of Mas receptor in the aorta of normotensive and hypertensive rats. IS downregulated the Mas receptor expression in a time- and dose-dependent manner in HASMCs. Knockdown of aryl hydrocarbon receptor (AhR) and nuclear factor-kappa B (NF-x03BA;B) inhibited IS-induced downregulation of Mas receptor. Further, IS stimulated cell proliferation and tissue factor expression in HASMCs. Ang-(1-7) attenuated IS-induced cell proliferation and tissue factor expression in HASMCs. Ang-(1-7) suppressed phosphorylation of extracellular signal-regulated kinase 1/2 (ERK1/2) and NF-x03BA;B in HASMCs. IS downregulated the expression of Mas receptor via AhR/NF-x03BA;B, and induced cell proliferation and tissue factor expression in HASMCs. Ang-(1-7) inhibited IS-induced cell proliferation and tissue factor expression by suppressing the phosphorylation of ERK1/2 and NF-x03BA;B p65. © 2016 S. Karger AG, Basel.

  11. Benzo[a]pyrene/aryl hydrocarbon receptor signaling inhibits osteoblastic differentiation and collagen synthesis of human periodontal ligament cells.

    Science.gov (United States)

    Monnouchi, S; Maeda, H; Yuda, A; Serita, S; Wada, N; Tomokiyo, A; Akamine, A

    2016-12-01

    Cigarette smoking has detrimental effects on periodontal tissue, and is known to be a risk factor for periodontal disease, including the loss of alveolar bone and ligament tissue. However, the direct effects of cigarette smoking on periodontal tissue remain unclear. Recently, we demonstrated that benzo[a]pyrene (BaP), which is a prototypic member of polycyclic aryl hydrocarbons and forms part of the content of cigarettes, attenuated the expression of extracellular matrix remodeling-related genes in human periodontal ligament (PDL) cells (HPDLCs). Thus, we aimed to examine the effects of BaP on the osteoblastic differentiation and collagen synthesis of HPDLCs. HPDLCs were obtained from healthy molars of three patients, and quantitative reverse transcription-polymerase chain reaction were performed for gene expression analyses of cytochrome P450 1A1 and 1B1, alkaline phosphatase, bone sialoprotein and aryl hydrocarbon receptor (AhR), a receptor for polycyclic aryl hydrocarbons. We have also analyzed the role of the AhR, using 2-methyl-2H-pyrazole-3-carboxylic acid (2-methyl-4-o-tolylazo-phenyl)-amide (CH-223191), which is an AhR antagonist. The treatment of HPDLCs with BaP reduced mRNA expression of osteogenic genes, alkaline phosphatase activity, mineralization and collagen synthesis. The treatment with CH-223191 subsequently restored the observed suppressive effects of BaP on HPDLCs. The present results suggest that BaP exerts inhibitory effects on the maintenance of homeostasis in HPDL tissue, such as osteoblastic differentiation and collagen synthesis of HPDLCs, and that this signaling pathway could be suppressed by preventing the transactivity of AhR. Future studies may unveil a role for the inhibition of AhR as a promising therapeutic agent for periodontal disease caused by cigarette smoking. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  12. Transient Suppression of TGFβ Receptor Signaling Facilitates Human Islet Transplantation.

    Science.gov (United States)

    Xiao, Xiangwei; Fischbach, Shane; Song, Zewen; Gaffar, Iljana; Zimmerman, Ray; Wiersch, John; Prasadan, Krishna; Shiota, Chiyo; Guo, Ping; Ramachandran, Sabarinathan; Witkowski, Piotr; Gittes, George K

    2016-04-01

    Although islet transplantation is an effective treatment for severe diabetes, its broad application is greatly limited due to a shortage of donor islets. Suppression of TGFβ receptor signaling in β-cells has been shown to increase β-cell proliferation in mice, but has not been rigorously examined in humans. Here, treatment of human islets with a TGFβ receptor I inhibitor, SB-431542 (SB), significantly improved C-peptide secretion by β-cells, and significantly increased β-cell number by increasing β-cell proliferation. In addition, SB increased cell-cycle activators and decreased cell-cycle suppressors in human β-cells. Transplantation of SB-treated human islets into diabetic immune-deficient mice resulted in significant improvement in blood glucose control, significantly higher serum and graft insulin content, and significantly greater increases in β-cell proliferation in the graft, compared with controls. Thus, our data suggest that transient suppression of TGFβ receptor signaling may improve the outcome of human islet transplantation, seemingly through increasing β-cell number and function.

  13. Stimulation of cannabinoid receptor 2 (CB2 suppresses microglial activation

    Directory of Open Access Journals (Sweden)

    Fernandez Francisco

    2005-12-01

    Full Text Available Abstract Background Activated microglial cells have been implicated in a number of neurodegenerative disorders, including Alzheimer's disease (AD, multiple sclerosis (MS, and HIV dementia. It is well known that inflammatory mediators such as nitric oxide (NO, cytokines, and chemokines play an important role in microglial cell-associated neuron cell damage. Our previous studies have shown that CD40 signaling is involved in pathological activation of microglial cells. Many data reveal that cannabinoids mediate suppression of inflammation in vitro and in vivo through stimulation of cannabinoid receptor 2 (CB2. Methods In this study, we investigated the effects of a cannabinoid agonist on CD40 expression and function by cultured microglial cells activated by IFN-γ using RT-PCR, Western immunoblotting, flow cytometry, and anti-CB2 small interfering RNA (siRNA analyses. Furthermore, we examined if the stimulation of CB2 could modulate the capacity of microglial cells to phagocytise Aβ1–42 peptide using a phagocytosis assay. Results We found that the selective stimulation of cannabinoid receptor CB2 by JWH-015 suppressed IFN-γ-induced CD40 expression. In addition, this CB2 agonist markedly inhibited IFN-γ-induced phosphorylation of JAK/STAT1. Further, this stimulation was also able to suppress microglial TNF-α and nitric oxide production induced either by IFN-γ or Aβ peptide challenge in the presence of CD40 ligation. Finally, we showed that CB2 activation by JWH-015 markedly attenuated CD40-mediated inhibition of microglial phagocytosis of Aβ1–42 peptide. Taken together, these results provide mechanistic insight into beneficial effects provided by cannabinoid receptor CB2 modulation in neurodegenerative diseases, particularly AD.

  14. Induction of Colonic Regulatory T Cells by Mesalamine by Activating the Aryl Hydrocarbon Receptor.

    Science.gov (United States)

    Oh-Oka, Kyoko; Kojima, Yuko; Uchida, Koichiro; Yoda, Kimiko; Ishimaru, Kayoko; Nakajima, Shotaro; Hemmi, Jun; Kano, Hiroshi; Fujii-Kuriyama, Yoshiaki; Katoh, Ryohei; Ito, Hiroyuki; Nakao, Atsuhito

    2017-07-01

    Mesalamine is a first-line drug for treatment of inflammatory bowel diseases (IBD). However, its mechanisms are not fully understood. CD4+ Foxp3+ regulatory T cells (Tregs) play a potential role in suppressing IBD. This study determined whether the anti-inflammatory activity of mesalamine is related to Treg induction in the colon. We examined the frequencies of Tregs in the colons of wild-type mice, mice deficient for aryl hydrocarbon receptor (AhR-/- mice), and bone marrow-chimeric mice lacking AhR in hematopoietic cells (BM-AhR-/- mice), following oral treatment with mesalamine. We also examined the effects of mesalamine on transforming growth factor (TGF)-β expression in the colon. Treatment of wild-type mice with mesalamine increased the accumulation of Tregs in the colon and up-regulated the AhR target gene Cyp1A1, but this effect was not observed in AhR-/- or BM-AhR-/- mice. In addition, mesalamine promoted in vitro differentiation of naive T cells to Tregs, concomitant with AhR activation. Mice treated with mesalamine exhibited increased levels of the active form of TGF-β in the colon in an AhR-dependent manner and blockade of TGF-β signaling suppressed induction of Tregs by mesalamine in the colon. Furthermore, mice pretreated with mesalamine acquired resistance to dextran sodium sulfate-induced colitis. We propose a novel anti-inflammatory mechanism of mesalamine for colitis: induction of Tregs in the colon via the AhR pathway, followed by TGF-β activation.

  15. Effect of nonpersistent pesticides on estrogen receptor, androgen receptor, and aryl hydrocarbon receptor.

    Science.gov (United States)

    Medjakovic, Svjetlana; Zoechling, Alfred; Gerster, Petra; Ivanova, Margarita M; Teng, Yun; Klinge, Carolyn M; Schildberger, Barbara; Gartner, Michael; Jungbauer, Alois

    2014-10-01

    Nonpersistent pesticides are considered less harmful for the environment, but their impact as endocrine disruptors has not been fully explored. The pesticide Switch was applied to grape vines, and the maximum residue concentration of its active ingredients was quantified. The transactivation potential of the pesticides Acorit, Frupica, Steward, Reldan, Switch, Cantus, Teldor, and Scala and their active compounds (hexythiazox, mepanipyrim, indoxacarb, chlorpyrifos-methyl, cyprodinil, fludioxonil, boscalid, fenhexamid, and pyrimethanil) were tested on human estrogen receptor α (ERα), androgen receptor (AR) and arylhydrocarbon receptor (AhR) in vitro. Relative binding affinities of the pure pesticide constituents for AR and their effect on human breast cancer and prostate cancer cell lines were evaluated. Residue concentrations of Switch's ingredients were below maximum residue limits. Fludioxonil and fenhexamid were ERα agonists (EC50 -values of 3.7 and 9.0 μM, respectively) and had time-dependent effects on endogenous ERα-target gene expression (cyclin D1, progesterone receptor, and nuclear respiratory factor 1) in MCF-7 human breast cancer cells. Fludioxonil, mepanipyrim, cyprodinil, pyrimethanil, and chlorpyrifos-methyl were AhR-agonists (EC50 s of 0.42, 0.77, 1.4, 4.6, and 5.1 μM, respectively). Weak AR binding was shown for chlorpyrifos-methyl, cyprodinil, fenhexamid, and fludioxonil. Assuming a total uptake which does not take metabolism and clearance rates into account, our in vitro evidence suggests that pesticides could activate pathways affecting hormonal balance, even within permitted limits, thus potentially acting as endocrine disruptors. Copyright © 2013 Wiley Periodicals, Inc., a Wiley company.

  16. Smoke carcinogens cause bone loss through the aryl hydrocarbon receptor and induction of CYP1 enzymes

    Science.gov (United States)

    Smoking is a major risk factor for osteoporosis and fracture. Here, we show that smoke toxins and environmental chemicals such as benzo[a]pyrene (BaP), 2,3,7,8-tetrachlorodibenzo-pdioxin (TCDD), and 3-methyl cholanthrene, which are well known aryl hydrocarbon receptor (AHR) agonists, induce osteocla...

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

    Energy Technology Data Exchange (ETDEWEB)

    Moran, Tyler B.; Brannick, Katherine E.; Raetzman, Lori T., E-mail: raetzman@life.illinois.edu

    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.

  18. beta-TrCP inhibition reduces prostate cancer cell growth via upregulation of the aryl hydrocarbon receptor.

    Directory of Open Access Journals (Sweden)

    Udi Gluschnaider

    2010-02-01

    Full Text Available Prostate cancer is a common and heterogeneous disease, where androgen receptor (AR signaling plays a pivotal role in development and progression. The initial treatment for advanced prostate cancer is suppression of androgen signaling. Later on, essentially all patients develop an androgen independent stage which does not respond to anti hormonal treatment. Thus, alternative strategies targeting novel molecular mechanisms are required. beta-TrCP is an E3 ligase that targets various substrates essential for many aspects of tumorigenesis.Here we show that beta-TrCP depletion suppresses prostate cancer and identify a relevant growth control mechanism. shRNA targeted against beta-TrCP reduced prostate cancer cell growth and cooperated with androgen ablation in vitro and in vivo. We found that beta-TrCP inhibition leads to upregulation of the aryl hydrocarbon receptor (AhR mediating the therapeutic effect. This phenomenon could be ligand independent, as the AhR ligand 2,3,7,8-Tetrachlorodibenzo-p-Dioxin (TCDD did not alter prostate cancer cell growth. We detected high AhR expression and activation in basal cells and atrophic epithelial cells of human cancer bearing prostates. AhR expression and activation is also significantly higher in tumor cells compared to benign glandular epithelium.Together these observations suggest that AhR activation may be a cancer counteracting mechanism in the prostate. We maintain that combining beta-TrCP inhibition with androgen ablation could benefit advanced prostate cancer patients.

  19. Combined gene overexpression of neuropeptide Y and its receptor Y5 in the hippocampus suppresses seizures

    DEFF Research Database (Denmark)

    Gøtzsche, Casper René; Nikitidou, Litsa; Sørensen, Andreas Toft

    2012-01-01

    on kainate-induced motor seizures in rats. However, combined overexpression of Y5 receptors and neuropeptide Y exerted prominent suppression of seizures. This seizure-suppressant effect of combination gene therapy with Y5 receptors and neuropeptide Y was significantly stronger as compared to neuropeptide Y...

  20. Cytotoxicity and aryl hydrocarbon receptor-mediated activity of n-heterocyclic polycyclic aromatic hydrocarbons: structure-activity relationships.

    Science.gov (United States)

    Sovadinová, Iva; Bláha, Ludĕk; Janosek, Jaroslav; Hilscherová, Klára; Giesy, John P; Jones, Paul D; Holoubek, Ivan

    2006-05-01

    Toxic effects of many persistent organic pollutants (e.g., polychlorinated biphenyls or polychlorinated dibenzo-p-dioxins and furans) are mediated via the aryl hydrocarbon receptor (AhR). Although polycyclic aromatic hydrocarbons (PAHs) and their derivatives also activate AhR, their toxic effects remain to be fully elucidated. In the present study, we used the in vitro H4IIE-luc transactivation cell assay to investigate cytotoxicity and potencies to activate AhR by 29 individual PAHs and their N-heterocyclic derivatives (aza-PAHs). The aza-PAHs were found to be significantly more cytotoxic and more potent inducers of AhR than their unsubstituted analogues. Several aza-PAHs, such as dibenz[a,h]acridine or dibenz[a,i]acridine, activated AhR within picomolar concentrations, comparable to the effects of reference 2,3,7,8-tetrachlorodibenzo-p-dioxin. Ellipsoidal volume, molar refractivity, and molecular size were the most important descriptors derived from the modeling of quantitative structure-activity relationships for potencies to activate AhR. Comparable relative toxic potencies (induction equivalency factors) for individual aza-PAHs are derived, and their use for evaluation of complex contaminated samples is discussed.

  1. In vitro function of the aryl hydrocarbon receptor predicts in vivo sensitivity of oviparous vertebrates to dioxin-like compounds

    Science.gov (United States)

    Differences in sensitivity to dioxin-like compounds (DLCs) among species and taxa presents a major challenge to ecological risk assessments. Activation of the aryl hydrocarbon receptor (AHR) regulates adverse effects associated with exposure to DLCs in vertebrates. Prior investig...

  2. GATA Factor-G-Protein-Coupled Receptor Circuit Suppresses Hematopoiesis

    Directory of Open Access Journals (Sweden)

    Xin Gao

    2016-03-01

    Full Text Available Hematopoietic stem cells (HSCs originate from hemogenic endothelium within the aorta-gonad-mesonephros (AGM region of the mammalian embryo. The relationship between genetic circuits controlling stem cell genesis and multi-potency is not understood. A Gata2 cis element (+9.5 enhances Gata2 expression in the AGM and induces the endothelial to HSC transition. We demonstrated that GATA-2 rescued hematopoiesis in +9.5−/− AGMs. As G-protein-coupled receptors (GPCRs are the most common targets for FDA-approved drugs, we analyzed the GPCR gene ensemble to identify GATA-2-regulated GPCRs. Of the 20 GATA-2-activated GPCR genes, four were GATA-1-activated, and only Gpr65 expression resembled Gata2. Contrasting with the paradigm in which GATA-2-activated genes promote hematopoietic stem and progenitor cell genesis/function, our mouse and zebrafish studies indicated that GPR65 suppressed hematopoiesis. GPR65 established repressive chromatin at the +9.5 site, restricted occupancy by the activator Scl/TAL1, and repressed Gata2 transcription. Thus, a Gata2 cis element creates a GATA-2-GPCR circuit that limits positive regulators that promote hematopoiesis.

  3. Activation of the aryl hydrocarbon receptor by TCDD inhibits mammary tumor metastasis in a syngeneic mouse model of breast cancer.

    Science.gov (United States)

    Wang, Tao; Wyrick, Katie L; Meadows, Gary G; Wills, Tamara B; Vorderstrasse, Beth A

    2011-12-01

    Treatment with aryl hydrocarbon receptor (AhR) agonists can slow or reverse the growth of primary mammary tumors in rodents, which has fostered interest in developing selective AhR modulators for treatment of breast cancer. However, the major goal of breast cancer therapy is to inhibit metastasis, the primary cause of mortality in women with this disease. Studies conducted using breast cancer cell lines have demonstrated that AhR agonists suppress proliferation, invasiveness, and colony formation in vitro; however, further exploration using in vivo models of metastasis is warranted. To test the effect of AhR activation on metastasis, 4T1.2 mammary tumor cells were injected into the mammary gland fat pad of syngeneic Balb/c mice treated with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Primary tumor growth was monitored for 4 weeks, at which time metastasis was determined. TCDD treatment suppressed metastasis by approximately 50%, as measured both in the lung and in mammary glands at sites distant from the primary tumor. Primary tumor growth was not suppressed by TCDD exposure nor was proliferation of 4T1.2 cells affected by TCDD treatment in vitro. Taken together, these results suggest that the protective effect of AhR activation was selective for the metastatic process and not simply the result of a direct decrease in tumor cell proliferation or survival at the primary site. These observations in immunologically intact animals warrant further investigation into the mechanism of the protective effects of AhR activation and support the promise for use of AhR modulators to treat breast cancer.

  4. Novel technique to suppress hydrocarbon contamination for high accuracy determination of carbon content in steel by FE-EPMA.

    Science.gov (United States)

    Yamashita, Takako; Tanaka, Yuji; Yagoshi, Masayasu; Ishida, Kiyohito

    2016-07-19

    In multiphase steels, control of the carbon contents in the respective phases is the most important factor in alloy design for achieving high strength and high ductility. However, it is unusually difficult to determine the carbon contents in multiphase structures with high accuracy by electron probe microanalysis (EPMA) due to the unavoidable effect of hydrocarbon contamination during measurements. We have investigated new methods for suppressing hydrocarbon contamination during field emission (FE) EPMA measurements as well as a conventional liquid nitrogen trap. Plasma cleaner inside the specimen chamber results in a improvement of carbon-content determination by point analysis, increasing precision tenfold from the previous 0.1 mass%C to 0.01 mass%C. Stage heating at about 100 °C dramatically suppresses contamination growth during continuous point measurement and mapping. By the combination of above two techniques, we successfully visualized the two-dimensional carbon distribution in a dual-phase steel. It was also noted that the carbon concentrations at the ferrite/martensite interfaces were not the same across all interfaces, and local variation was observed. The developed technique is expected to be a powerful tool for understanding the mechanisms of mechanical properties and microstructural evolution, thereby contributing to the design of new steel products with superior properties.

  5. Novel technique to suppress hydrocarbon contamination for high accuracy determination of carbon content in steel by FE-EPMA

    Science.gov (United States)

    Yamashita, Takako; Tanaka, Yuji; Yagoshi, Masayasu; Ishida, Kiyohito

    2016-07-01

    In multiphase steels, control of the carbon contents in the respective phases is the most important factor in alloy design for achieving high strength and high ductility. However, it is unusually difficult to determine the carbon contents in multiphase structures with high accuracy by electron probe microanalysis (EPMA) due to the unavoidable effect of hydrocarbon contamination during measurements. We have investigated new methods for suppressing hydrocarbon contamination during field emission (FE) EPMA measurements as well as a conventional liquid nitrogen trap. Plasma cleaner inside the specimen chamber results in a improvement of carbon-content determination by point analysis, increasing precision tenfold from the previous 0.1 mass%C to 0.01 mass%C. Stage heating at about 100 °C dramatically suppresses contamination growth during continuous point measurement and mapping. By the combination of above two techniques, we successfully visualized the two-dimensional carbon distribution in a dual-phase steel. It was also noted that the carbon concentrations at the ferrite/martensite interfaces were not the same across all interfaces, and local variation was observed. The developed technique is expected to be a powerful tool for understanding the mechanisms of mechanical properties and microstructural evolution, thereby contributing to the design of new steel products with superior properties.

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

    NARCIS (Netherlands)

    Wang, J.; Bovee, T.F.H.; Bi, Y.; Bernhöft, S.; Schramm, K.W.

    2014-01-01

    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

  7. Quercetin suppresses insulin receptor signaling through inhibition of the insulin ligand–receptor binding and therefore impairs cancer cell proliferation

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Feng [Department of Gastroenterology, The Tenth People’s Hospital of Shanghai, Tongji University, Shanghai 200072 (China); Department of Nanomedicine, Houston Methodist Research Institute, Houston, TX 77030 (United States); Yang, Yong, E-mail: yyang@houstonmethodist.org [Department of Nanomedicine, Houston Methodist Research Institute, Houston, TX 77030 (United States); Department of Medicine, Weill Cornell Medical College, New York, NY 10065 (United States)

    2014-10-03

    Graphical abstract: - Highlights: • Quercetin inhibits insulin ligand–receptor interactions. • Quercetin reduces downstream insulin receptor signaling. • Quercetin blocks insulin induced glucose uptake. • Quercetin suppresses insulin stimulated cancer cell proliferation and tumor growth. - Abstract: Although the flavonoid quercetin is known to inhibit activation of insulin receptor signaling, the inhibitory mechanism is largely unknown. In this study, we demonstrate that quercetin suppresses insulin induced dimerization of the insulin receptor (IR) through interfering with ligand–receptor interactions, which reduces the phosphorylation of IR and Akt. This inhibitory effect further inhibits insulin stimulated glucose uptake due to decreased cell membrane translocation of glucose transporter 4 (GLUT4), resulting in impaired cancer cell proliferation. The effect of quercetin in inhibiting tumor growth was also evident in an in vivo model, indicating a potential future application for quercetin in the treatment of cancers.

  8. Structure and Dimerization Properties of the Aryl Hydrocarbon Receptor PAS-A Domain

    Science.gov (United States)

    Wu, Dalei; Potluri, Nalini; Kim, Youngchang

    2013-01-01

    The aryl hydrocarbon receptor (AHR) is a ligand-dependent transcription factor that binds to xenobiotics and responds by regulating the expression of gene programs required for detoxification and metabolism. AHR and its heterodimerization partner aryl hydrocarbon receptor nuclear translocator (ARNT) belong to the basic helix-loop-helix (bHLH)–PER-ARNT-SIM (PAS) family of transcription factors. Here we report the 2.55-Å-resolution crystal structure of the mouse AHR PAS-A domain, which represents the first AHR-derived protein structure. The AHR PAS-A domain forms a helix-swapped homodimer in the crystal and also in solution. Through a detailed mutational analysis of all interface residues, we identified several hydrophobic residues that are important for AHR dimerization and function. Our crystallographic visualization of AHR PAS-A dimerization leads us to propose a mode of heterodimerization with ARNT that is supported by both biochemical and cell-based data. Our studies also highlight the residues of other mammalian bHLH-PAS proteins that are likely involved in their homo- or heterodimerization. PMID:24001774

  9. Genetic dissection of endothelial transcriptional activity of zebrafish aryl hydrocarbon receptors (AHRs)

    Science.gov (United States)

    Sugden, Wade W.; Leonardo-Mendonça, Roberto C.; Acuña-Castroviejo, Darío

    2017-01-01

    The aryl hydrocarbon receptor (AHR) is a basic helix-loop-helix transcription factor conserved across phyla from flies to humans. Activated by a number of endogenous ligands and environmental toxins, studies on AHR function and gene regulation have largely focused on a toxicological perspective relating to aromatic hydrocarbons generated by human activities and the often-deleterious effects of exposure on vertebrates mediated by AHR activation. A growing body of work has highlighted the importance of AHR in physiologic processes, including immune cell differentiation and vascular patterning. Here we dissect the contribution of the 3 zebrafish AHRs, ahr1a, ahr1b and ahr2, to endothelial cyp1a1/b1 gene regulation under physiologic conditions and upon exposure to the AHR ligand Beta-naphthoflavone. We show that in fish multiple AHRs are functional in the vasculature, with vessel-specific differences in the ability of ahr1b to compensate for the loss of ahr2 to maintain AHR signaling. We further provide evidence that AHR can regulate the expression of the chemokine receptor cxcr4a in endothelial cells, a regulatory mechanism that may provide insight into AHR function in the endothelium. PMID:28817646

  10. Insulin receptor substrate signaling suppresses neonatal autophagy in the heart

    National Research Council Canada - National Science Library

    Riehle, Christian; Wende, Adam R; Sena, Sandra; Pires, Karla Maria; Pereira, Renata Oliveira; Zhu, Yi; Bugger, Heiko; Frank, Deborah; Bevins, Jack; Chen, Dong; Perry, Cynthia N; Dong, Xiaocheng C; Valdez, Steven; Rech, Monika; Sheng, Xiaoming; Weimer, Bart C; Gottlieb, Roberta A; White, Morris F; Abel, E Dale

    2013-01-01

    .... Insulin signaling in the heart is transduced via insulin and IGF-1 receptors (IGF-1Rs). We disrupted insulin and IGF-1R signaling by generating mice with combined cardiomyocyte-specific deletion of Irs1 and Irs2...

  11. Insulin/insulin like growth factors in cancer: new roles for the aryl hydrocarbon receptor, tumor resistance mechanisms and new blocking strategies

    Directory of Open Access Journals (Sweden)

    Travis B Salisbury

    2015-02-01

    Full Text Available The insulin-like growth factor 1 receptor (IGF1R and the insulin receptor (IR are receptor tyrosine kinases (RTKs that are expressed in cancer cells. The results of different studies indicate that tumor proliferation and survival is dependent on the IGF1R and IR, and that their inhibition leads to reductions in proliferation and increases in cell death. Molecular targeting therapies that have been used in solid tumors include: anti-IGF1R antibodies, anti-IGF1/IGF2 antibodies and small molecule inhibitors that suppress IGF1R and IR kinase activity. New advances in the molecular basis of anti-IGF1R blocking antibodies reveal they are biased agonists and promote the binding of IGF1 to integrin β3 receptors in some cancer cells. Our recent reports indicate that pharmacological aryl hydrocarbon receptor (AHR ligands inhibit breast cancer cell responses to IGFs, suggesting that targeting AHR may have benefit in cancers whose proliferation and survival are dependent on insulin/IGF signaling. Novel aspects of IGF1R/IR in cancer, such as biased agonism, integrin β3 signaling, AHR and new therapeutic targeting strategies will be discussed.

  12. Effect of dioxins on regulation of tyrosine hydroxylase gene expression by aryl hydrocarbon receptor: a neurotoxicology study

    Directory of Open Access Journals (Sweden)

    Akahoshi Eiichi

    2009-06-01

    Full Text Available Abstract Background Dioxins and related compounds are suspected of causing neurological disruption. Epidemiological studies indicated that exposure to these compounds caused neurodevelopmental disturbances such as learning disability and attention deficit hyperactivity disorder, which are thought to be closely related to dopaminergic dysfunction. Although the molecular mechanism of their actions has not been fully investigated, a major participant in the process is aryl hydrocarbon receptor (AhR. This study focused on the effect of 2, 3, 7, 8-tetrachlorodibenzo-p-dioxin (TCDD exposure on the regulation of TH, a rate-limiting enzyme of dopamine synthesis, gene expression by AhR. Methods N2a-Rβ cells were established by transfecting murine neuroblastoma Neuro2a with the rat AhR cDNA. TH expression induced by TCDD was assessed by RT-PCR and Western blotting. Participation of AhR in TCDD-induced TH gene expression was confirmed by suppressing AhR expression using the siRNA method. Catecholamines including dopamine were measured by high-performance liquid chromatography. A reporter gene assay was used to identify regulatory motifs in the promoter region of TH gene. Binding of AhR with the regulatory motif was confirmed by an electrophoretic mobility shift assay (EMSA. Results Induction of TH by TCDD through AhR activation was detected at mRNA and protein levels. Induced TH protein was functional and its expression increased dopamine synthesis. The reporter gene assay and EMSA indicated that AhR directly regulated TH gene expression. Regulatory sequence called aryl hydrocarbon receptor responsive element III (AHRE-III was identified upstream of the TH gene from -285 bp to -167 bp. Under TCDD exposure, an AhR complex was bound to AHRE-III as well as the xenobiotic response element (XRE, though AHRE-III was not identical to XRE, the conventional AhR-binding motif. Conclusion Our results suggest TCDD directly regulate the dopamine system by TH gene

  13. Interleukin-24 as a target cytokine of environmental aryl hydrocarbon receptor agonist exposure in the lung.

    Science.gov (United States)

    Luo, Yueh-Hsia; Kuo, Yu-Chun; Tsai, Ming-Hsien; Ho, Chia-Chi; Tsai, Hui-Ti; Hsu, Chin-Yu; Chen, Yu-Cheng; Lin, Pinpin

    2017-06-01

    Exposure to environmental aryl hydrocarbon receptor (AhR) agonists, such as halogenated aromatic hydrocarbons and polycyclic aromatic hydrocarbons (PAHs), has great impacts on the development of various lung diseases. As emerging molecular targets for AhR agonists, cytokines may contribute to the inflammatory or immunotoxic effects of environmental AhR agonists. However, general cytokine expression may not specifically indicate environmental AhR agonist exposure. By comparing cytokine and chemokine expression profiles in human lung adenocarcinoma cell line CL5 treated with AhR agonists and the non-AhR agonist polychlorinated biphenyl (PCB) 39, we identified a target cytokine of environmental AhR agonist exposure of in the lungs. Thirteen cytokine and chemokine genes were altered in the AhR agonists-treated cells, but none were altered in the PCB39-treated cells. Interleukin (IL)-24 was the most highly induced gene among AhR-modulated cytokines. Cotreatment with AhR antagonist completely prevented IL-24 induction by AhR agonists in the CL5 cells. Knockdown AhR expression with short-hairpin RNA (shRNA) significantly reduced benzo[a]pyrene (BaP)-induced IL-24 mRNA levels. We further confirmed that gene transcription, but not mRNA stability, was involved in IL-24 upregulation by BaP. Particulate matter (PM) in the ambient air contains some PAHs and is reported to activate AhR. Oropharyngeal aspiration of PM significantly increased IL-24 levels in lung epithelia and in bronchoalveolar lavage fluid of mice 4weeks after treatment. Thus, our data suggests that IL-24 is a pulmonary exposure target cytokine of environmental AhR agonists. Copyright © 2017 Elsevier Inc. All rights reserved.

  14. Regulating the regulator: factors that control levels and activity of the aryl hydrocarbon receptor.

    Science.gov (United States)

    Harper, Patricia A; Riddick, David S; Okey, Allan B

    2006-07-28

    The aryl hydrocarbon receptor (AHR) participates in a wide range of critical cellular events in response to endogenous signals or xenobiotic chemicals. Hence, it is important that AHR levels and activity themselves be well controlled in target tissues. The AHR is essentially ubiquitous in its distribution in mammalian tissues. However, levels of the receptor vary widely across different tissues and among different cell types. AHR levels and activity are modulated by exposure to the receptor's own ligands and are influenced by other xenobiotic chemicals. Many different factors impinge on AHR levels and AHR activity. These factors may alter responsiveness of downstream pathways, thereby affecting normal physiologic functions as well as responses to toxic environmental chemicals such as dioxins. Our commentary appraises the current literature on factors that regulate AHR levels/activity and attempts to identify fruitful strategies towards discovery of key pathways by which AHR levels are modulated in response to endogenous signals and in response to xenobiotic chemicals. An extraordinarily large number of agents alter the level or activity of the AHR. We have not yet entered an age of enlightenment sufficient to achieve true understanding of the interplay of mechanisms that regulate AHR expression in space and in time.

  15. Cell specific effects of PCB 126 on aryl hydrocarbone receptors in follicular cells of porcine ovaries

    Energy Technology Data Exchange (ETDEWEB)

    Wojtowicz, A.; Augustowska, K.; Gregoraszczuk, E. [Lab. of Physiology and Toxicology of Reproduction, Dept. of Animal Physiology, Inst. of Zoology, Jagiellonian Univ., Krakow (Poland)

    2004-09-15

    Polychlorinated biphenyles (PCBs) like other endocrine disrupters could interfere with natural hormones by binding to their receptors and thus mimicking the cellular response to them. They are known to possess either estrogenic or antiestrogenic properties. In our previous papers we demonstrated that PCBs are able to disrupt ovarian steroidogenesis. We found that the coplanar PCB 126 caused the decrease in estradiol secretion in whole cultured pig ovarian follicles. PCB 126 congener is structurally related to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Since TCDD effects are known to be mediated by aryl hydrocarbone receptors (AhRs), we decided to determine if PCB 126 affects signal transduction pathway activated by these receptors. It has been reported that the functional AhR is present in ovary including oocytes, granulosa and theca cells of rat, mouse, rhesus monkey and human ovary. Moreover, the expression of AhR in the rat ovary appeared to be estrous cycle-dependent, thus suggesting that AhR expression may be regulated by fluctuating hormone levels. This study was designed to investigate the effects of the non-ortho-substituted 3,3',4,4',5-pentachlorobiphenyl (PCB126) on the AhR activation, localization and protein level in pig ovarian follicle cells.

  16. Molecular identification and partial sequence analysis of an aryl hydrocarbon receptor from beluga (Delphinapterus leucas)

    Energy Technology Data Exchange (ETDEWEB)

    Jensen, B.A.; Hahn, M.E. [Woods Hole Oceanographic Institution, MA (United States)

    1995-12-31

    The aryl hydrocarbon receptor (AhR) mediates the effects of many common and potentially toxic organic hydrocarbons, including some polychlorinated biphenyls and dioxins. Since small cetaceans often inhabit industrially polluted coastal waters, comparison of the molecular structure and function of this protein in cetaeans with other marine and mammalian species is important for evaluating the sensitivity of cetaceans to these pollutants. An AhR protein has been identified in beluga liver by photoaffinity labeling. In the present study, the authors sought to clone and sequence an AhR cDNA from beluga as a prelude to studying its structure and function, using reverse-transcription polymerase chain reaction (RT-PCR) and degenerate primers, a 515 base pair fragment was amplified, cloned and sequenced, revealing homology to the PAS domain (ligand binding and dimerization region) of AhRs from terrestrial mammals. This portion of the putative beluga AhR has 82% amino acid and 81% nucleotide sequence identity to the mouse AhR, and 63% amino acid and 64% nucleotide sequence identity to an AhR from the marine fish Fundulus heteroclitus. A beluga cDNA library was synthesized and is currently being screened with the PCR-generated fragment to obtain the complete coding sequence. This is the first molecular evidence of AhR presence in cetaceans.

  17. Aryl hydrocarbon receptor-independent toxicity of weathered crude oil during fish development.

    Science.gov (United States)

    Incardona, John P; Carls, Mark G; Teraoka, Hiroki; Sloan, Catherine A; Collier, Tracy K; Scholz, Nathaniel L

    2005-12-01

    Polycyclic aromatic hydrocarbons (PAHs), derived largely from fossil fuels and their combustion, are pervasive contaminants in rivers, lakes, and nearshore marine habitats. Studies after the Exxon Valdez oil spill demonstrated that fish embryos exposed to low levels of PAHs in weathered crude oil develop a syndrome of edema and craniofacial and body axis defects. Although mechanisms leading to these defects are poorly understood, it is widely held that PAH toxicity is linked to aryl hydrocarbon receptor (AhR) binding and cytochrome P450 1A (CYP1A) induction. Using zebrafish embryos, we show that the weathered crude oil syndrome is distinct from the well-characterized AhR-dependent effects of dioxin toxicity. Blockade of AhR pathway components with antisense morpholino oligonucleotides demonstrated that the key developmental defects induced by weathered crude oil exposure are mediated by low-molecular-weight tricyclic PAHs through AhR-independent disruption of cardiovascular function and morphogenesis. These findings have multiple implications for the assessment of PAH impacts on coastal habitats.

  18. Polymorphism of the aryl-hydrocarbon receptor gene in intron 10 of human cancers.

    Science.gov (United States)

    Rocas, M; Jakubauskiene, E; Kanopka, A

    2011-11-01

    Polychlorinated dibenzo-p-dioxins (PCDDs) and related halogenated aromatic hydrocarbons (e.g., PCDFs), often called "dioxins", are ubiquitously present environmental contaminants. Some of them, notably 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), are among the most toxic synthetic compounds known. The biological effects of dioxins are mediated via the aryl hydrocarbon receptor (AhR). Mutations in the AhR transactivation domain are linked to sensitivity to the acute lethality of TCDD. We present here a study of AhR gene polymorphism in normal and cancer human tissues affecting pre-mRNA splicing in the AhR gene-coding transactivation domain region (exon 10, intron 10, exon 11 region), previously shown to be associated with AhR dysfunction. We tested 126 pairs of normal and cancer tissue samples from liver, lung, stomach, kidney, mucous, breast, and pancreas of 49 males and 77 females (45-70 years of age). We used in vitro splicing assay, RT-PCR and sequencing methods. Our results showed that in an in vitro system it is possible to reconstitute cellular pre-mRNA splicing events. Tested cancer tissues did not contain mutations in the AhR transactivation domain region when the DNA sequences were compared with those from normal tissues. There were also no differences in AhR mRNA splice variants between normal and malignant breast tissues and no polymorphisms in the studied regions or cDNA.

  19. Polymorphism of the aryl-hydrocarbon receptor gene in intron 10 of human cancers

    Directory of Open Access Journals (Sweden)

    M. Rocas

    2011-11-01

    Full Text Available Polychlorinated dibenzo-p-dioxins (PCDDs and related halogenated aromatic hydrocarbons (e.g., PCDFs, often called "dioxins", are ubiquitously present environmental contaminants. Some of them, notably 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD, are among the most toxic synthetic compounds known. The biological effects of dioxins are mediated via the aryl hydrocarbon receptor (AhR. Mutations in the AhR transactivation domain are linked to sensitivity to the acute lethality of TCDD. We present here a study of AhR gene polymorphism in normal and cancer human tissues affecting pre-mRNA splicing in the AhR gene-coding transactivation domain region (exon 10, intron 10, exon 11 region, previously shown to be associated with AhR dysfunction. We tested 126 pairs of normal and cancer tissue samples from liver, lung, stomach, kidney, mucous, breast, and pancreas of 49 males and 77 females (45-70 years of age. We used in vitro splicing assay, RT-PCR and sequencing methods. Our results showed that in an in vitro system it is possible to reconstitute cellular pre-mRNA splicing events. Tested cancer tissues did not contain mutations in the AhR transactivation domain region when the DNA sequences were compared with those from normal tissues. There were also no differences in AhR mRNA splice variants between normal and malignant breast tissues and no polymorphisms in the studied regions or cDNA.

  20. Screening a mouse liver gene expression Compendium Identifies Effectors of the Aryl Hydrocarbon receptor (AhR)

    Science.gov (United States)

    The aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor that mediates the biological and toxic effects of 2,3, 7 ,8-tetrachlorodibenzo-p-dioxin {TCDD), dioxin-like compounds (DLC) as well as some drugs and endogenous tryptophan metabolites. Short-term act...

  1. Aryl hydrocarbon receptor ligand effects in RBL2H3 cells

    DEFF Research Database (Denmark)

    Maaetoft-Udsen, Kristina; Shimoda, Lori M. N.; Frøkiær, Hanne

    2012-01-01

    The aryl hydrocarbon receptor (AHR) mediates toxic effects of dioxin and xenobiotic metabolism. AHR has an emerging role in the immune system, but its physiological ligands and functional role in immunocytes remain poorly understood. Mast cells are immunocytes that are central to inflammatory...... responses and release a spectrum of pro-inflammatory mediators including histamine, mast cell proteases, and pro-inflammatory cytokines such as IL-6 upon stimulation. The aim was to investigate the AHR in model mast cells and examine how both putative and known AHR ligands, e.g., kynurenine, kynurenic acid...... (KA), Resveratrol, indolmycin, and violacein, affect mast cell activation and signaling. These ligands were tested on calcium signaling, degranulation, and gene expression. The data show that AHR is present in three model mast cell lines, and that various known and putative AHR ligands regulate gene...

  2. Enzyme induction and histopathology elucidate aryl hydrocarbon receptor-mediated versus non-aryl hydrocarbon receptor-mediated effects of Aroclor 1268 in American mink (Neovison vison).

    Science.gov (United States)

    Folland, William R; Newsted, John L; Fitzgerald, Scott D; Fuchsman, Phyllis C; Bradley, Patrick W; Kern, John; Kannan, Kurunthachalam; Zwiernik, Matthew J

    2016-03-01

    Polychlorinated biphenyl (PCB) concentrations reported in preferred prey and blubber of bottlenose dolphins from the Turtle-Brunswick River estuary (Georgia, USA) suggest the potential for adverse effects. However, PCBs in Turtle-Brunswick River estuary dolphins are primarily derived from Aroclor 1268, and predicting toxic effects of Aroclor 1268 is uncertain because of the mixture's unique composition and associated physiochemical characteristics. These differences suggest that toxicity benchmarks for other PCB mixtures may not be relevant to dolphins exposed to Aroclor 1268. American mink (Neovison vison) were used as a surrogate model for cetaceans to characterize mechanisms of action associated with Aroclor 1268 exposure. Mink share similarities in phylogeny and life history with cetaceans and are characteristically sensitive to PCBs, making them an attractive surrogate species for marine mammals in ecotoxicity studies. Adult female mink and a subsequent F1 generation were exposed to Aroclor 1268 through diet, and effects on enzyme induction, histopathology, thyroid hormone regulation, hematology, organ weights, and body condition index were compared to a negative control and a 3,3',4,4',5-pentachlorobiphenyl (PCB 126)-positive control. Aroclor 1268 dietary exposure concentrations ranged from 1.8 µg/g wet weight to 29 µg/g wet weight. Anemia, hypothyroidism, and hepatomegaly were observed in mink exposed to Aroclor 1268 beyond various dietary thresholds. Cytochrome P450 induction and squamous epithelial proliferation jaw lesions were low in Aroclor 1268 treatments relative to the positive control. Differences in enzyme induction and the development of squamous epithelial proliferation jaw lesions between Aroclor 1268 treatments and the positive control, coupled with effects observed in Aroclor 1268 treatments not observed in the positive control, indicate that mechanisms additional to the aryl hydrocarbon receptor-mediated pathway are associated with

  3. Effect of grazing seedhead-suppressed tall fescue pasture on the vasoactivity of serotonin receptors

    Science.gov (United States)

    Previous research has demonstrated that exposure to ergot alkaloids reduces vasoactivity of serotonin (5HT) receptors. Chemical suppression of tall fescue seedhead production is a tool to reduce the level of exposure to ergot alkaloids by a grazing animal. Therefore, the objective was to evaluate co...

  4. Obesity is mediated by differential aryl hydrocarbon receptor signaling in mice fed a Western diet.

    Science.gov (United States)

    Kerley-Hamilton, Joanna S; Trask, Heidi W; Ridley, Christian J A; Dufour, Eric; Ringelberg, Carol S; Nurinova, Nilufer; Wong, Diandra; Moodie, Karen L; Shipman, Samantha L; Moore, Jason H; Korc, Murray; Shworak, Nicholas W; Tomlinson, Craig R

    2012-09-01

    Obesity is a growing worldwide problem with genetic and environmental causes, and it is an underlying basis for many diseases. Studies have shown that the toxicant-activated aryl hydrocarbon receptor (AHR) may disrupt fat metabolism and contribute to obesity. The AHR is a nuclear receptor/transcription factor that is best known for responding to environmental toxicant exposures to induce a battery of xenobiotic-metabolizing genes. The intent of the work reported here was to test more directly the role of the AHR in obesity and fat metabolism in lieu of exogenous toxicants. We used two congenic mouse models that differ at the Ahr gene and encode AHRs with a 10-fold difference in signaling activity. The two mouse strains were fed either a low-fat (regular) diet or a high-fat (Western) diet. The Western diet differentially affected body size, body fat:body mass ratios, liver size and liver metabolism, and liver mRNA and miRNA profiles. The regular diet had no significant differential effects. The results suggest that the AHR plays a large and broad role in obesity and associated complications, and importantly, may provide a simple and effective therapeutic strategy to combat obesity, heart disease, and other obesity-associated illnesses.

  5. The aryl hydrocarbon receptor ligand omeprazole inhibits breast cancer cell invasion and metastasis.

    Science.gov (United States)

    Jin, Un-Ho; Lee, Syng-Ook; Pfent, Catherine; Safe, Stephen

    2014-07-09

    Patients with ER-negative breast tumors are among the most difficult to treat and exhibit low survival rates due, in part, to metastasis from the breast to various distal sites. Aryl hydrocarbon receptor (AHR) ligands show promise as antimetastatic drugs for estrogen receptor (ER)-negative breast cancer. Triple negative MDA-MB-231 breast cancer cells were treated with eight AHR-active pharmaceuticals including 4-hydroxtamoxifen, flutamide leflunomide, mexiletine, nimodipine, omeprazole, sulindac and tranilast, and the effects of these compounds on cell proliferation (MTT assay) and cell migration (Boyden chamber assay) were examined. The role of the AHR in mediating inhibition of MDA-MB-231 cell invasion was investigated by RNA interference (RNAi) and knockdown of AHR or cotreatment with AHR agonists. Lung metastasis of MDA-MB-231 cells was evaluated in mice administered cells by tail vein injection and prometastatic gene expression was examined by immunohistochemistry. We showed that only the proton pump inhibitor omeprazole decreased MDA-MB-231 breast cancer cell invasion in vitro. Omeprazole also significantly decreased MDA-MB-231 cancer cell metastasis to the lung in a mouse model (tail vein injection), and in vitro studies showed that omeprazole decreased expression of at least two prometastatic genes, namely matrix metalloproteinase-9 (MMP-9) and C-X-C chemokine receptor 4 (CXCR4). Results of RNA interference studies confirmed that omeprazole-mediated downregulation of CXCR4 (but not MMP-9) was AHR-dependent. Chromatin immunoprecipitation assays demonstrated that omeprazole recruited the AHR to regions in the CXCR4 promoter that contain dioxin response elements (DREs) and this was accompanied by the loss of pol II on the promoter and decreased expression of CXCR4. AHR-active pharmaceuticals such as omeprazole that decrease breast cancer cell invasion and metastasis may have important clinical applications for late stage breast cancer chemotherapy.

  6. Impaired glucose and lipid metabolism in ageing aryl hydrocarbon receptor deficient mice

    Science.gov (United States)

    Biljes, Daniel; Hammerschmidt-Kamper, Christiane; Kadow, Stephanie; Diel, Patrick; Weigt, Carmen; Burkart, Volker; Esser, Charlotte

    2015-01-01

    Disturbed homeostasis of glucose and lipid metabolism are dominant features of the so-called metabolic syndrome (MetS) and can increase the risk for the development of type 2 diabetes (T2D), a severe metabolic disease. T2D prevalence increases with age. The aryl hydrocarbon receptor (AHR) is a sensor of small molecules including dietary components. AHR has been identified as potential regulator of glucose homeostasis and lipid metabolism. Epidemiologically, exposure to xenobiotic AHR ligands such as polycyclic aromatic hydrocarbons is linked to T2D. We assess here the potential role of the AHR in disturbances of glucose and lipid metabolism in young (age 2-5 months) and old (age > 1,5 years) AHR-deficient (AHR KO) mice. Fasted young wildtype (WT) and AHR-KO mice displayed similar blood glucose kinetics after challenge with intra-peritoneal glucose injection. However, old AHR-KO mice showed lower tolerance than WT to i.p. administered glucose, i.e. glucose levels rose higher and returned more slowly to normal levels. Old mice had overall higher insulin levels than young mice, and old AHR-KO had a somewhat disturbed insulin kinetic in the serum after glucose challenge. Surprisingly, young AHR-KO mice had significantly lower triglycerides, cholesterol, high density lipoprotein values than WT, i.e., a dyslipidemic profile. With ageing, AHR-KO and WT mice did not differ in these lipid levels, except for slightly reduced levels of triglycerides and cholesterol. In conclusion, our findings in AHR KO mice suggest that AHR expression is relevant for the maintenance of glucose and lipid homeostasis in old mice. PMID:26664351

  7. A novel role of the aryl hydrocarbon receptor (AhR in centrosome amplification - implications for chemoprevention

    Directory of Open Access Journals (Sweden)

    Chatterjee Payel

    2010-06-01

    Full Text Available Abstract Background Centrosome aberrations can cause genomic instability and correlate with malignant progression in common human malignancies such as breast and prostate cancer. Deregulation of cyclin/cyclin-dependent kinase 2 (CDK2 activity has previously been shown to be critically involved in centrosome overduplication. We therefore test here whether small molecule CDK inhibitors derived from the bis-indole indirubin can be used to suppress centrosome aberrations as a novel approach to chemoprevention of malignant progression. Results As expected, we found that the CDK inhibitor indirubin-3'-oxime (IO suppresses centrosome amplification in breast cancer cells. However, we made the unexpected discovery that indirubin-derived compounds that have been chemically modified to be inactive as kinase inhibitors such as 1-methyl-indirubin-3'-oxime (MeIO still significantly reduced centrosome amplification. All indirubins used in the present study are potent agonists of the aryl hydrocarbon receptor (AhR, which is known for its important role in the cellular metabolism of xenobiotics. To corroborate our results, we first show that the coincidence of nuclear AhR overexpression, reflecting a constitutive activation, and numerical centrosome aberrations correlates significantly with malignancy in mammary tissue specimens. Remarkably, a considerable proportion (72.7% of benign mammary tissue samples scored also positive for nuclear AhR overexpression. We furthermore provide evidence that continued expression of endogenous AhR is critical to promote centriole overduplication induced by cyclin E and that AhR and cyclin E may function in the same pathway. Overexpression of the AhR in the absence of exogenous ligands was found to rapidly disrupt centriole duplication control. Nonetheless, the AhR agonists IO and MeIO were still found to significantly reduce centriole overduplication stimulated by ectopic AhR expression. Conclusions Our results indicate that

  8. The aryl hydrocarbon receptor mediates raloxifene-induced apoptosis in estrogen receptor-negative hepatoma and breast cancer cells.

    Science.gov (United States)

    O'Donnell, E F; Koch, D C; Bisson, W H; Jang, H S; Kolluri, S K

    2014-01-30

    Identification of new molecular targets for the treatment of breast cancer is an important clinical goal, especially for triple-negative breast cancer, which is refractory to existing targeted treatments. The aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor known primarily as the mediator of dioxin toxicity. However, the AhR can also inhibit cellular proliferation in a ligand-dependent manner and act as a tumor suppressor in mice, and thus may be a potential anticancer target. To investigate the AhR as an anticancer target, we conducted a small molecule screen to discover novel AhR ligands with anticancer properties. We identified raloxifene, a selective estrogen receptor (ER) modulator currently used in the clinic for prevention of ER-positive breast cancer and osteoporosis in post-menopausal women, as an AhR activator. Raloxifene directly bound the AhR and induced apoptosis in ER-negative mouse and human hepatoma cells in an AhR-dependent manner, indicating that the AhR is a molecular target of raloxifene and mediates raloxifene-induced apoptosis in the absence of ER. Raloxifene selectively induced apoptosis of triple-negative MDA-MB-231 breast cancer cells compared with non-transformed mammary epithelial cells via the AhR. Combined with recent data showing that raloxifene inhibits triple-negative breast cancer xenografts in vivo (Int J Oncol. 43(3):785-92, 2013), our results support the possibility of repurposing of raloxifene as an AhR-targeted therapeutic for triple-negative breast cancer patients. To this end, we also evaluated the role of AhR expression on survival of patients diagnosed with breast cancer. We found that higher expression of the AhR is significantly associated with increased overall survival and distant metastasis-free survival in both hormone-dependent (ER-positive) and hormone-independent (ER and progesterone receptor (PR)-negative) breast cancers. Together, our data strongly support the possibility of using the Ah

  9. Umami-bitter interactions: the suppression of bitterness by umami peptides via human bitter taste receptor.

    Science.gov (United States)

    Kim, Min Jung; Son, Hee Jin; Kim, Yiseul; Misaka, Takumi; Rhyu, Mee-Ra

    2015-01-09

    Taste-taste interactions often showed in human psychophysical studies. Considering that each tastant in foodstuffs individually stimulates its responsible gustatory systems to elicit relevant taste modalities, taste-taste interaction should be performed in taste receptor cell-based assay. While umami substances have been proposed to suppress the bitterness of various chemicals in human sensory evaluation, the bitter-umami interaction has not been explored in bitter taste receptors, TAS2Rs. We investigated umami-bitter taste interactions by presenting umami peptides with bitter substance (salicin) on Ca(2+)-flux signaling assay using hTAS2R16-expressing cells. Five representative umami peptides (Glu-Asp, Glu-Glu, Glu-Ser, Asp-Glu-Ser, and Glu-Gly-Ser) derived from soybean markedly attenuated the salicin-induced intracellular calcium influx in a time-dependent manner, respectively, while Gly-Gly, a tasteless peptide did not. The efficacies of Glu-Glu suppressing salicin-induced activation of hTAS2R16 were higher than that of probenecid, a specific antagonist of hTAS2R16. According to Ca(2+)-flux signaling assay using the mixtures of salicin and umami peptides, all five umami peptides suppressed salicin-induced intracellular calcium influx in a noncompetitive manner. These results may provide evidence that umami peptides suppress bitter taste via bitter taste receptor(s). This is the first report which defines the interaction between bitter and umami taste in taste receptor level. Copyright © 2014. Published by Elsevier Inc.

  10. Insulin like growth factor 2 regulation of aryl hydrocarbon receptor in MCF-7 breast cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Tomblin, Justin K.; Salisbury, Travis B., E-mail: salisburyt@marshall.edu

    2014-01-17

    Highlights: •IGF-2 stimulates concurrent increases in AHR and CCND1 expression. •IGF-2 promotes the binding of AHR to the endogenous cyclin D1 promoter. •AHR knockdown inhibits IGF-2 stimulated increases in CCND1 mRNA and protein. •AHR knockdown inhibits IGF-2 stimulated increases in MCF-7 proliferation. -- Abstract: Insulin like growth factor (IGF)-1 and IGF-2 stimulate normal growth, development and breast cancer cell proliferation. Cyclin D1 (CCND1) promotes cell cycle by inhibiting retinoblastoma protein (RB1). The aryl hydrocarbon receptor (AHR) is a major xenobiotic receptor that also regulates cell cycle. The purpose of this study was to investigate whether IGF-2 promotes MCF-7 breast cancer proliferation by inducing AHR. Western blot and quantitative real time PCR (Q-PCR) analysis revealed that IGF-2 induced an approximately 2-fold increase (P < .001) in the expression of AHR and CCND1. Chromatin immunoprecipitation (ChIP), followed by Q-PCR indicated that IGF-2 promoted (P < .001) a 7-fold increase in AHR binding on the CCND1 promoter. AHR knockdown significantly (P < .001) inhibited IGF-2 stimulated increases in CCND1 mRNA and protein. AHR knockdown cells were less (P < .001) responsive to the proliferative effects of IGF-2 than control cells. Collectively, our findings have revealed a new regulatory mechanism by which IGF-2 induction of AHR promotes the expression of CCND1 and the proliferation of MCF-7 cells. This previously uncharacterized pathway could be important for the proliferation of IGF responsive cancer cells that also express AHR.

  11. Prostate tumor progression in the TRAMP mouse. Protective effects of the aryl hydrocarbon receptor

    Energy Technology Data Exchange (ETDEWEB)

    Fritz, W.; Lin, T.M.; Peterson, R. [Wisconsin Univ., Madison, WI (United States)

    2004-09-15

    The developing male reproductive system is highly sensitive to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). TCDD binds to the aryl hydrocarbon receptor (AhR), a ligand-activated transcription factor, to produce sustained alterations in gene expression. Mice lacking the AhR (AhRKO, Ahr{sup -/-}) have permitted further characterization of the role of the AhR in mediating TCDD effects and revealed a physiological role for the AhR in normal development. We previously demonstrated that in utero and lactational TCDD exposure significantly reduced ventral, dorsolateral and anterior prostate weights, and that these effects were dependent on the AhR5. However, reductions in prostate lobe weights in untreated, AhRKO mice compared to wild-type counterparts at various ages demonstrated that the AhR signaling pathway is involved in normal development of the dorsolateral and anterior prostates, but apparently not the ventral prostate. Unaltered serum testosterone concentrations and modest reduction in serum 5{alpha}-androstane-3{alpha},17{beta}a-diol concentrations could not account for reductions in prostate weights in mice lacking AhR (Ahr{sup -/-}). Normal histology and lack of alteration in androgen receptor mRNA levels further indicate that the reduction in prostate weights is not a result of reduced androgen action in AhRKO mice. The observation that regulation of early prostate growth in mice occurs following AhR activation by TCDD, as well as by loss of AhR, suggests that the AhR may also regulate aberrant prostate growth that results from ''reawakening'' of the prostate growth regulatory signals later in life. Our objective was to determine if the AhR signaling pathway has an effect on prostate cancer development.

  12. Interactions between polymorphisms in the aryl hydrocarbon receptor signalling pathway and exposure to persistent organochlorine pollutants affect human semen quality

    DEFF Research Database (Denmark)

    Brokken, L J S; Lundberg, P J; Spanò, M

    2014-01-01

    Persistent organic pollutants (POPs) may affect male reproductive function. Many dioxin-like POPs exert their effects by activation of the aryl hydrocarbon receptor (AHR) signalling pathway. We analysed whether gene-environment interactions between polymorphisms in AHR (R554K) and AHR repressor (...... and the expression of the pro-apoptotic marker protein Fas. The data indicate that susceptibility to adverse effects of POP exposure on male reproductive function is dependent on polymorphisms in genes involved in AHR signalling....

  13. Pluripotency factors and Polycomb Group proteins repress aryl hydrocarbon receptor expression in murine embryonic stem cells

    Directory of Open Access Journals (Sweden)

    Chia-I Ko

    2014-01-01

    Full Text Available The aryl hydrocarbon receptor (AHR is a transcription factor and environmental sensor that regulates expression of genes involved in drug-metabolism and cell cycle regulation. Chromatin immunoprecipitation analyses, Ahr ablation in mice and studies with orthologous genes in invertebrates suggest that AHR may also play a significant role in embryonic development. To address this hypothesis, we studied the regulation of Ahr expression in mouse embryonic stem cells and their differentiated progeny. In ES cells, interactions between OCT3/4, NANOG, SOX2 and Polycomb Group proteins at the Ahr promoter repress AHR expression, which can also be repressed by ectopic expression of reprogramming factors in hepatoma cells. In ES cells, unproductive RNA polymerase II binds at the Ahr transcription start site and drives the synthesis of short abortive transcripts. Activation of Ahr expression during differentiation follows from reversal of repressive marks in Ahr promoter chromatin, release of pluripotency factors and PcG proteins, binding of Sp factors, establishment of histone marks of open chromatin, and engagement of active RNAPII to drive full-length RNA transcript elongation. Our results suggest that reversible Ahr repression in ES cells holds the gene poised for expression and allows for a quick switch to activation during embryonic development.

  14. Omeprazole Attenuates Hyperoxic Injury in H441 Cells via Aryl hydrocarbon Receptor

    Science.gov (United States)

    Shivanna, Binoy; Chu, Chun; Welty, Stephen E.; Jiang, Weiwu; Wang, Lihua; Moorthy, Bhagavatula

    2014-01-01

    Hyperoxia contributes to the development of bronchopulmonary dysplasia in premature infants. Earlier we observed that aryl hydrocarbon receptor (AhR)-deficient mice are more susceptible to hyperoxic lung injury than AhR-sufficient mice, and this phenomenon was associated with a lack of expression of cytochrome P450 1A enzymes. Omeprazole, a proton pump inhibitor, used in humans with gastric acid related disorders, activates AhR in hepatocytes in vitro. However, the effects of omeprazole on AhR activation in the lungs and its impact on hyperoxia-induced ROS generation and inflammation are unknown. In this study, we tested the hypothesis that omeprazole attenuates hyperoxia-induced cytotoxicity, ROS generation, and expression of monocyte chemoattractant protein-1 (MCP-1) in the human lung derived H441 cells via AhR activation. Experimental groups included cells transfected with AhR small interfering RNA (siRNA). Hyperoxia resulted in significant increases in cytotoxicity, ROS generation, and MCP-1 production, which were significantly attenuated with the functional activation of AhR by omeprazole. The protective effects of omeprazole on cytotoxicity, ROS production, and MCP-1 production were lost in H441 cells whose AhR gene was silenced by AhR siRNA. These findings support the hypothesis that omeprazole protects against hyperoxic injury in vitro via AhR activation that is associated with decreased ROS generation and expression of MCP-1. PMID:21906671

  15. The Unexpected Role for the Aryl Hydrocarbon Receptor on Susceptibility to Experimental Toxoplasmosis

    Directory of Open Access Journals (Sweden)

    Yuriko Sanchez

    2010-01-01

    Full Text Available The aryl hydrocarbon receptor (AhR is part of a signaling system that is mainly triggered by xenobiotic agents. Increasing evidence suggests that AhR may regulate immunity to infections. To determine the role of AhR in the outcome of toxoplasmosis, we used AhR-/- and wild-type (WT mice. Following an intraperitoneal infection with Toxoplasma gondii (T. gondii, AhR-/- mice succumbed significantly faster than WT mice and displayed greater liver damage as well as higher serum levels of tumor necrosis factor (TNF-α, nitric oxide (NO, and IgE but lower IL-10 secretion. Interestingly, lower numbers of cysts were found in their brains. Increased mortality was associated with reduced expression of GATA-3, IL-10, and 5-LOX mRNA in spleen cells but higher expression of IFN-γ mRNA. Additionally, peritoneal exudate cells from AhR-/- mice produced higher levels of IL-12 and IFN-γ but lower TLR2 expression than WT mice. These findings suggest a role for AhR in limiting the inflammatory response during toxoplasmosis.

  16. Association of aryl hydrocarbon receptor-related gene variants with the severity of autism spectrum disorders

    Directory of Open Access Journals (Sweden)

    Takashi X. Fujisawa

    2016-11-01

    Full Text Available Exposure to environmental chemicals, such as dioxin, is known to have adverse effects on the homeostasis of gonadal steroids, thereby potentially altering the sexual differentiation of the brain to express autistic traits. Dioxin-like chemicals act on the aryl hydrocarbon receptor (AhR, polymorphisms and mutations of AhR-related gene may exert pathological influences on sexual differentiation of the brain, causing autistic traits. To ascertain the relationship between AhR-related gene polymorphisms and autism susceptibility, we identified genotypes of them in patients and controls and determined whether there are different gene and genotype distributions between both groups. In addition, to clarify the relationships between the polymorphisms and the severity of autism, we compared the two genotypes of AhR-related genes (rs2066853, rs2228099 with the severity of autistic symptoms. Although no statistically significant difference was found between autism spectrum disorder (ASD patients and control individuals for the genotypic distribution of any of the polymorphisms studied herein, a significant difference in the total score of severity was observed in rs2228099 polymorphism, suggesting that the polymorphism modifies the severity of ASD symptoms but not ASD susceptibility. Moreover, we found that a significant difference in the social communication score of severity was observed. These results suggest that the rs2228099 polymorphism is possibly associated with the severity of social communication impairment among the diverse ASD symptoms.

  17. Interaction of fish aryl hydrocarbon receptor paralogs (AHR1 and AHR2) with the retinoblastoma protein

    Energy Technology Data Exchange (ETDEWEB)

    Merson, Rebeka R., E-mail: rmerson@ric.edu [Biology Department, Woods Hole Oceanographic Institution, Woods Hole, MA 02543 (United States); Biology Department, Rhode Island College, 500 Mt. Pleasant Ave., Providence, RI 02908 (United States); Karchner, Sibel I.; Hahn, Mark E. [Biology Department, Woods Hole Oceanographic Institution, Woods Hole, MA 02543 (United States)

    2009-08-13

    The aryl hydrocarbon receptor (AHR) mediates the toxic effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and related compounds. In some mammalian cell lines, TCDD induces G1 cell cycle arrest, which depends on an interaction between the AHR and the retinoblastoma tumor suppressor (RB). Mammals possess one AHR, whereas fishes possess two or more AHR paralogs that differ in the domains important for AHR-RB interactions in mammals. To test the hypothesis that fish AHR paralogs differ in their ability to interact with RB, we cloned RB cDNA from Atlantic killifish, Fundulus heteroclitus, and studied the interactions of killifish RB protein with killifish AHR1 and AHR2. In coimmunoprecipitation experiments, in vitro-expressed killifish RB coprecipitated with both AHR1 and AHR2. Consistent with these results, both killifish AHR1 and AHR2 interacted with RB in mammalian two-hybrid assays. These results suggest that both fish AHR1 and AHR2 paralogs may have the potential to influence cell proliferation through interactions with RB.

  18. Offspring DNA methylation of the aryl-hydrocarbon receptor repressor gene is associated with maternal BMI, gestational age, and birth weight

    OpenAIRE

    Burris, Heather H.; Baccarelli, Andrea A; Byun, Hyang-Min; Cantoral, Alejandra; Just, Allan C.; Pantic, Ivan; Solano-Gonzalez, Maritsa; Svensson, Katherine; Tamayo y Ortiz, Marcela; ZHAO, YAN; Robert O Wright; Téllez-Rojo, Martha M.

    2015-01-01

    Prenatal smoke exposure, maternal obesity, aberrant fetal growth, and preterm birth are all risk factors for offspring metabolic syndrome. Cord blood aryl-hydrocarbon receptor repressor (AHRR) DNA methylation is responsive to maternal smoking during pregnancy. AHRR serves not only to inhibit aryl-hydrocarbon receptor (AHR) transcription, which is involved in mediating xenobiotic metabolism, but it is also involved in cell growth and differentiation. Other than maternal smoking, other predicto...

  19. Low concentrations of bisphenol a suppress thyroid hormone receptor transcription through a nongenomic mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Sheng, Zhi-Guo [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Science, Chinese Academy of Sciences, 18 Shuangqing Road, Beijing 100085 (China); Tang, Yuan [Department of Pharmaceutics, College of Pharmacy, Third Military Medical University, 30 Yanzheng Street, Chongqing 400038 (China); Liu, Yu-Xiang [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Science, Chinese Academy of Sciences, 18 Shuangqing Road, Beijing 100085 (China); Yuan, Ye; Zhao, Bao-Quan [Beijing Institute of Pharmacology and Toxicology, 27 Taiping Road, Beijing 100850 (China); Chao, Xi-Juan [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Science, Chinese Academy of Sciences, 18 Shuangqing Road, Beijing 100085 (China); Zhu, Ben-Zhan, E-mail: bzhu@rcees.ac.cn [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Science, Chinese Academy of Sciences, 18 Shuangqing Road, Beijing 100085 (China)

    2012-02-15

    Bisphenol (BPA) is one of the highest-volume chemicals produced worldwide, and human exposure to BPA is thought to be ubiquitous. Various rodent and in vitro studies have shown that thyroid hormone (TH) function can be impaired by BPA. However, it is still unknown if low concentrations of BPA can suppress the thyroid hormone receptor (TR) transcription. The present study aims to investigate the possible suppressing effects of low concentrations of BPA on TR transcription and the involved mechanism(s) in CV-1 cells derived from cercopithecus aethiops monkey kidneys. Using gene reporter assays, BPA at concentrations as low as 10{sup −9} M suppresses TR or steroid receptor coactivator-1(SRC-1)-enhanced TR transcription, but not reducing TR/SRC-1 interaction in mammalian two-hybrid and glutathione S-transferase pull-down studies. It has been further shown that both nuclear receptor co-repressor (N-CoR) and silencing mediator for retinoid and thyroid hormone receptors (SMRT) are recruited to the TR-β1 by BPA in the presence of physiologic concentrations of T3 or T4. However, the overexpression of β3 integrin or c-Src significantly reduces BPA-induced recruitment of N-CoR/SMRT to TR or suppression of TR transcription. Furthermore, BPA inhibits the T3/T4-mediated interassociation of the β3 integrin/c-Src/MAPK/TR-β1 pathways by the co-immunoprecipitation. These results indicate that low concentrations of BPA suppress the TR transcription by disrupting physiologic concentrations of T3/T4-mediated β3 integrin/c-Src/MAPK/TR-β1 pathways, followed by recruiting N-CoR/SMRT to TR-β1, providing a novel insight regarding the TH disruption effects of low concentration BPA. -- Highlights: ► Environmentally relevant concentrations of BPA suppress TR transcription. ► BPA recruits the N-CoR/SMRT to TR under the physiologic concentrations of T3/T4. ► BPA disrupts T3/T4-mediated β3 integrin/c-Src/MAPK/TR-β1 pathways.

  20. Aryl hydrocarbon receptor-independent up-regulation of intracellular calcium concentration by environmental polycyclic aromatic hydrocarbons in human endothelial HMEC-1 cells.

    Science.gov (United States)

    Mayati, Abdullah; Le Ferrec, Eric; Lagadic-Gossmann, Dominique; Fardel, Olivier

    2012-09-01

    Polycyclic aromatic hydrocarbons (PAHs) such as benzo(a)pyrene (B(a)P) constitute a major family of widely-distributed environmental toxic contaminants, known as potent ligands of the aryl hydrocarbon receptor (AhR). B(a)P has been recently shown to trigger an early and transient increase of intracellular calcium concentration ([Ca(2+)](i)), involved in AhR-related up-regulation of target genes by B(a)P. This study was designed to determine whether AhR may play a role in [Ca(2+)](i) induction provoked by B(a)P. We demonstrated that, in addition to B(a)P, various PAHs, including pyrene and benzo(e)pyrene, known to not or only very poorly interact with AhR, similarly up-regulated [Ca(2+)](i) in human endothelial HMEC-1 cells. Moreover, α-naphthoflavone, a flavonoïd antagonist of AhR, was also able to induce [Ca(2+)](i). Knocking-down AhR expression in HMEC-1 cells through transfection of siRNAs, was finally demonstrated to not prevent B(a)P-mediated induction of [Ca(2+)](i), whereas it efficiently counteracted B(a)P-mediated induction of the referent AhR target gene cytochrome P-450 1B1. Taken together, these data demonstrate that environmental PAHs trigger [Ca(2+)](i) induction in an AhR-independent manner.

  1. Artificial sweeteners stimulate adipogenesis and suppress lipolysis independently of sweet taste receptors.

    Science.gov (United States)

    Simon, Becky R; Parlee, Sebastian D; Learman, Brian S; Mori, Hiroyuki; Scheller, Erica L; Cawthorn, William P; Ning, Xiaomin; Gallagher, Katherine; Tyrberg, Björn; Assadi-Porter, Fariba M; Evans, Charles R; MacDougald, Ormond A

    2013-11-08

    G protein-coupled receptors mediate responses to a myriad of ligands, some of which regulate adipocyte differentiation and metabolism. The sweet taste receptors T1R2 and T1R3 are G protein-coupled receptors that function as carbohydrate sensors in taste buds, gut, and pancreas. Here we report that sweet taste receptors T1R2 and T1R3 are expressed throughout adipogenesis and in adipose tissues. Treatment of mouse and human precursor cells with artificial sweeteners, saccharin and acesulfame potassium, enhanced adipogenesis. Saccharin treatment of 3T3-L1 cells and primary mesenchymal stem cells rapidly stimulated phosphorylation of Akt and downstream targets with functions in adipogenesis such as cAMP-response element-binding protein and FOXO1; however, increased expression of peroxisome proliferator-activated receptor γ and CCAAT/enhancer-binding protein α was not observed until relatively late in differentiation. Saccharin-stimulated Akt phosphorylation at Thr-308 occurred within 5 min, was phosphatidylinositol 3-kinase-dependent, and occurred in the presence of high concentrations of insulin and dexamethasone; phosphorylation of Ser-473 occurred more gradually. Surprisingly, neither saccharin-stimulated adipogenesis nor Thr-308 phosphorylation was dependent on expression of T1R2 and/or T1R3, although Ser-473 phosphorylation was impaired in T1R2/T1R3 double knock-out precursors. In mature adipocytes, artificial sweetener treatment suppressed lipolysis even in the presence of forskolin, and lipolytic responses were correlated with phosphorylation of hormone-sensitive lipase. Suppression of lipolysis by saccharin in adipocytes was also independent of T1R2 and T1R3. These results suggest that some artificial sweeteners have previously uncharacterized metabolic effects on adipocyte differentiation and metabolism and that effects of artificial sweeteners on adipose tissue biology may be largely independent of the classical sweet taste receptors, T1R2 and T1R3.

  2. Artificial Sweeteners Stimulate Adipogenesis and Suppress Lipolysis Independently of Sweet Taste Receptors*

    Science.gov (United States)

    Simon, Becky R.; Parlee, Sebastian D.; Learman, Brian S.; Mori, Hiroyuki; Scheller, Erica L.; Cawthorn, William P.; Ning, Xiaomin; Gallagher, Katherine; Tyrberg, Björn; Assadi-Porter, Fariba M.; Evans, Charles R.; MacDougald, Ormond A.

    2013-01-01

    G protein-coupled receptors mediate responses to a myriad of ligands, some of which regulate adipocyte differentiation and metabolism. The sweet taste receptors T1R2 and T1R3 are G protein-coupled receptors that function as carbohydrate sensors in taste buds, gut, and pancreas. Here we report that sweet taste receptors T1R2 and T1R3 are expressed throughout adipogenesis and in adipose tissues. Treatment of mouse and human precursor cells with artificial sweeteners, saccharin and acesulfame potassium, enhanced adipogenesis. Saccharin treatment of 3T3-L1 cells and primary mesenchymal stem cells rapidly stimulated phosphorylation of Akt and downstream targets with functions in adipogenesis such as cAMP-response element-binding protein and FOXO1; however, increased expression of peroxisome proliferator-activated receptor γ and CCAAT/enhancer-binding protein α was not observed until relatively late in differentiation. Saccharin-stimulated Akt phosphorylation at Thr-308 occurred within 5 min, was phosphatidylinositol 3-kinase-dependent, and occurred in the presence of high concentrations of insulin and dexamethasone; phosphorylation of Ser-473 occurred more gradually. Surprisingly, neither saccharin-stimulated adipogenesis nor Thr-308 phosphorylation was dependent on expression of T1R2 and/or T1R3, although Ser-473 phosphorylation was impaired in T1R2/T1R3 double knock-out precursors. In mature adipocytes, artificial sweetener treatment suppressed lipolysis even in the presence of forskolin, and lipolytic responses were correlated with phosphorylation of hormone-sensitive lipase. Suppression of lipolysis by saccharin in adipocytes was also independent of T1R2 and T1R3. These results suggest that some artificial sweeteners have previously uncharacterized metabolic effects on adipocyte differentiation and metabolism and that effects of artificial sweeteners on adipose tissue biology may be largely independent of the classical sweet taste receptors, T1R2 and T1R3. PMID

  3. A role of aryl hydrocarbon receptor in the antiandrogenic effects of polycyclic aromatic hydrocarbons in LNCaP human prostate carcinoma cells

    Energy Technology Data Exchange (ETDEWEB)

    Kizu, Ryoichi; Okamura, Kazumasa; Toriba, Akira; Hayakawa, Kazuichi [Graduate School of Natural Science and Technology, Kanazawa University, 13-1 Takara-machi, Kanazawa 920-0934 (Japan); Kakishima, Hiroshi [Research Planning Department, Eiken Chemical Co. Ltd., 5-26-20 Oji, Kita-ku, Tokyo 114-0002 (Japan); Mizokami, Atsushi [School of Medicine, Kanazawa University, 13-1 Takara-machi, Kanazawa 920-8641 (Japan); Burnstein, Kerry L. [Department of Molecular and Cellular Pharmacology, University of Miami School of Medicine, FL 33101, Miami (United States)

    2003-06-01

    The role of aryl hydrocarbon receptor (AhR) on the antiandrogenic effects of polycyclic aromatic hydrocarbons (PAHs) was studied in LNCaP cells. The PAHs used in this study were chrysene (Chr), benzo[k]fluoranthene (BkF), benzo[a]pyrene (BaP), anthracene (Ant) and pyrene (Pyr). Chr, BkF and BaP acted as AhR agonists in LNCaP cells, while Ant and Pyr did not. The antiandrogenic effects of the PAHs were evaluated on the basis of regulation of prostate-specific antigen (PSA) mRNA and protein levels by 5{alpha}-dihydrotestosterone (DHT). Chr, BkF and BaP exhibited an antiandrogenic effect, but Ant and Pyr did not. {alpha}-Naphthoflavone ({alpha}-NF), an AhR antagonist, reversed the antiandrogen action of Chr, BkF and BaP, suggesting a requirement for activated AhR. The antiandrogenic PAHs did not significantly decrease androgen receptor (AR) levels or cellular DHT concentrations. Gel mobility shift assays revealed that Chr, BkF and BaP inhibited the binding of AR in nuclear extracts to oligonucleotide probes containing the AR-responsive element (ARE), whereas Ant and Pyr had no effect. The antiandrogenic PAHs elevated mRNA levels of c-fos and c-jun. Since activator protein-1 (AP-1), a heterodimer of c-jun and c-fos proteins, is known to inhibit binding of AR to ARE by protein-protein interaction with AR, the findings in the present study suggest a possible involvement of AP-1 in the antiandrogenic effects of PAHs acting as AhR agonists. These results suggest that AhR can stimulate AP-1 expression resulting in inhibition of the binding of AR to ARE in the transcription regulatory region of target genes such as PSA. (orig.)

  4. Polycyclic Aromatic Hydrocarbons (PAHs) Mediate Transcriptional Activation of the ATP Binding Cassette Transporter ABCB6 Gene via the Aryl Hydrocarbon Receptor (AhR)*

    Science.gov (United States)

    Chavan, Hemantkumar; Krishnamurthy, Partha

    2012-01-01

    Liver is endowed with a mechanism to induce hepatic cytochromes P450 (CYP450s) in response to therapeutic drugs and environmental contaminants, leading to increased detoxification and elimination of the xenobiotics. Each CYP450 is composed of an apoprotein moiety and a heme prosthetic group, which is required for CYP450 activity. Thus, under conditions of CYP450 induction, there is a coordinate increase in heme biosynthesis to compensate for the increased expression of CYP450s. ABCB6, a mitochondrial ATP binding cassette transporter, which regulates coproporphyrinogen transport from the cytoplasm into the mitochondria to complete heme biosynthesis, represents a previously unrecognized rate-limiting step in heme biosynthesis. However, it is not known if exposure to drugs and environmental contaminants induces ABCB6 expression, to assure an adequate and apparently coordinated supply of heme for the generation of functional cytochrome holoprotein. In the present study, we demonstrate that polycyclic aromatic hydrocarbons (PAHs), the widely distributed environmental toxicants shown to induce porphyrin accumulation causing hepatic porphyria, up-regulate ABCB6 expression in both mice and humans. Using siRNA technology and Abcb6 knock-out mice, we demonstrate that PAH-mediated increase in hepatic porphyrins is compromised in the absence of ABCB6. Moreover, in vivo studies in aryl hydrocarbon receptor (AhR) knock-out mice demonstrate that PAH induction of ABCB6 is mediated by AhR. Promoter activation studies combined with electrophoretic mobility shift assay and chromatin immunoprecipitation assay demonstrate direct interactions between the AhR binding sites in the ABCB6 promoter and the AhR receptor, implicating drug activation mechanisms for ABCB6 similar to those found in inducible cytochrome P450s. These studies are the first to describe direct transcriptional activation of both mouse and human ABCB6 by xenobiotics. PMID:22761424

  5. Polycyclic aromatic hydrocarbons (PAHs) mediate transcriptional activation of the ATP binding cassette transporter ABCB6 gene via the aryl hydrocarbon receptor (AhR).

    Science.gov (United States)

    Chavan, Hemantkumar; Krishnamurthy, Partha

    2012-09-14

    Liver is endowed with a mechanism to induce hepatic cytochromes P450 (CYP450s) in response to therapeutic drugs and environmental contaminants, leading to increased detoxification and elimination of the xenobiotics. Each CYP450 is composed of an apoprotein moiety and a heme prosthetic group, which is required for CYP450 activity. Thus, under conditions of CYP450 induction, there is a coordinate increase in heme biosynthesis to compensate for the increased expression of CYP450s. ABCB6, a mitochondrial ATP binding cassette transporter, which regulates coproporphyrinogen transport from the cytoplasm into the mitochondria to complete heme biosynthesis, represents a previously unrecognized rate-limiting step in heme biosynthesis. However, it is not known if exposure to drugs and environmental contaminants induces ABCB6 expression, to assure an adequate and apparently coordinated supply of heme for the generation of functional cytochrome holoprotein. In the present study, we demonstrate that polycyclic aromatic hydrocarbons (PAHs), the widely distributed environmental toxicants shown to induce porphyrin accumulation causing hepatic porphyria, up-regulate ABCB6 expression in both mice and humans. Using siRNA technology and Abcb6 knock-out mice, we demonstrate that PAH-mediated increase in hepatic porphyrins is compromised in the absence of ABCB6. Moreover, in vivo studies in aryl hydrocarbon receptor (AhR) knock-out mice demonstrate that PAH induction of ABCB6 is mediated by AhR. Promoter activation studies combined with electrophoretic mobility shift assay and chromatin immunoprecipitation assay demonstrate direct interactions between the AhR binding sites in the ABCB6 promoter and the AhR receptor, implicating drug activation mechanisms for ABCB6 similar to those found in inducible cytochrome P450s. These studies are the first to describe direct transcriptional activation of both mouse and human ABCB6 by xenobiotics.

  6. Dietary tryptophan alleviates dextran sodium sulfate-induced colitis through aryl hydrocarbon receptor in mice.

    Science.gov (United States)

    Islam, Jahidul; Sato, Shoko; Watanabe, Kouichi; Watanabe, Takaya; Ardiansyah; Hirahara, Keisuke; Aoyama, Yukihide; Tomita, Shuhei; Aso, Hisashi; Komai, Michio; Shirakawa, Hitoshi

    2017-04-01

    Ulcerative colitis is the typical progression of chronic inflammatory bowel disease. Amino acids, particularly tryptophan, have been reported to exert a protective effect against colitis induced by dextran sodium sulfate (DSS), but the precise underlying mechanisms remain incompletely clarified. Tryptophan metabolites are recognized to function as endogenous ligands for aryl hydrocarbon receptor (Ahr), which is a critical regulator of inflammation and immunity. Thus, we conducted this study to investigate whether dietary tryptophan supplementation protects against DSS-induced colitis by acting through Ahr. Female wild-type (WT) and Ahr-deficient (knockout; KO) mice (10-12 weeks old) were divided into four groups and fed either a control or 0.5% tryptophan diet. The tryptophan diet ameliorated DSS-induced colitis symptoms and severity in WT mice but not in KO mice, and the diet reduced the mRNA expression of Il-6, Tnfα, Il-1β and the chemokines Ccl2, Cxcl1 and Cxcl2 in the WT groups. Furthermore, Il-22 and Stat3 mRNA expression in the colon was elevated in WT mice fed with the tryptophan diet, which mainly protected epithelial layer integrity, and Ahr also modulated immune homeostasis by regulating Foxp3 and Il-17 mRNA expression. These data suggest that tryptophan-containing diet might ameliorate DSS-induced acute colitis and regulate epithelial homeostasis through Ahr. Thus, tryptophan could serve as a promising preventive agent in the treatment of ulcerative colitis. Copyright © 2017 Elsevier Inc. All rights reserved.

  7. Omeprazole Inhibits Pancreatic Cancer Cell Invasion through a Nongenomic Aryl Hydrocarbon Receptor Pathway.

    Science.gov (United States)

    Jin, Un-Ho; Kim, Sang-Bae; Safe, Stephen

    2015-05-18

    Omeprazole and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) are aryl hydrocarbon receptor (AhR) agonists that inhibit the invasion of breast cancer cells through inhibition of CXCR4 transcription. Treatment of highly invasive Panc1 pancreatic cancer cells with TCDD, omeprazole, and seven other AhR-active pharmaceuticals showed that only omeprazole and tranilast, but not TCDD, inhibited invasion in a Boyden chamber assay. Similar results were observed in MiaPaCa2 cells, another quasimensenchymal pancreatic ductal adenocarcinoma (QM-PDA) pancreatic cancer cell line, whereas invasion was not observed with BxPC3 or L3.6pL cells, which are classified as classical (less invasive) pancreatic cancer cells. It was also observed in QM-PDA cells that TCDD, omeprazole, and tranilast did not induce CYP1A1 or CXCR4 and that treatment with these compounds did not result in nuclear uptake of AhR. In contrast, treatment of BxPC3 and L3.6pL cells with these AhR ligands resulted in induction of CYP1A1 (by TCDD) and nuclear uptake of AhR, which was similar to that observed for Ah-responsive MDA-MB-468 breast and HepG2 liver cancer cell lines. Results of AhR and AhR nuclear translocator (Arnt) knockdown experiments in Panc1 and MiaPaCa2 cells demonstrated that omeprazole- and tranilast-mediated inhibition of invasion was AhR-dependent but Arnt-independent. These results demonstrate that in the most highly invasive subtype of pancreatic cancer cells (QM-PDA) the selective AhR modulators omeprazole and tranilast inhibit invasion through a nongenomic AhR pathway.

  8. Correlating gene expression with deformities caused by aryl hydrocarbon receptor agonists in zebrafish (Danio rerio)

    Energy Technology Data Exchange (ETDEWEB)

    Bugiak, B.; Weber, L. [Saskatchewan Univ., Saskatoon, SK (Canada)

    2009-07-01

    Exposure to aryl hydrocarbon receptor (AhR) agonists in fish causes lethal disturbances in fish development, but the effects of acute AhR agonist exposure on the cardiovascular system and deformities remain unclear. This study addressed this issue by performing a series of experiments on zebrafish (Danio rerio). The authors hypothesized that genes needed for cardiovascular regulation (PTGS) would exhibit a stronger link to deformities than detoxification enzymes (CYPs). Zebrafish eggs were exposed aqueously until 4 days post-fertilization (dpf) to the AhR agonists benzo(a)pyrene (BaP) or 2,3,7,8-tetrachlorodibenzop-dioxin (TCDD) alone and in combination with the putative AhR antagonists resveratrol or alpha-naphthoflavone (ANF). Gene expression was measured using real-time, reverse transcriptase PCR in zebrafish at 5 and 10 dpf. Although the mortalities did not differ considerably among groups at 10 dpf, the deformities increased significantly after BaP-ANF at 5 dpf and after BaP at 10 dpf, but not after TCDD treatment. CYP and PTGS isozymes exhibited small, but statistically significant changes at 5 dpf. By 10 dpf, the expression returned to control values. In general, CYP1A and PTGS-1 expression at 5 dpf were positively correlated with deformities, while all other genes were negatively correlated with deformities. It was concluded that changes in CYP1A, CYP1C2, and PTGS-1 gene expression at 5 dpf are associated with developmental deformities, but additional work is needed to determine which has the most important mechanistic link.

  9. γ-Tocotrienol upregulates aryl hydrocarbon receptor expression and enhances the anticancer effect of baicalein

    Energy Technology Data Exchange (ETDEWEB)

    Yamashita, Shuya; Baba, Kiwako; Makio, Akiko; Kumazoe, Motofumi; Huang, Yuhui; Lin, I-Chian; Bae, Jaehoon; Murata, Motoki; Yamada, Shuhei; Tachibana, Hirofumi, E-mail: tatibana@agr.kyushu-u.ac.jp

    2016-05-13

    Previous studies have identified biomolecules that mediate the physiological actions of food factors, such as amino acids, vitamins, fatty acids, minerals, plant polyphenols, and lactobacilli, suggesting that our bodies are equipped with an innate system that senses which food factors are required to maintain our health. However, the effects of environmental factors on food factor sensing (FFS) remains largely unknown. Tocotorienols (T3s), which belongs to the vitamin E family, possess several physiological functions, including cholesterol lowering and neuroprotective effects. Here, we investigated the effects of naturally abundant γ-T3 on FFS-related gene expressions in melanoma using a DNA chip. Our results showed that γ-T3 increased the expression level of aryl hydrocarbon receptor (AhR), a sensing molecule to plant polyphenol baicalein. The co-treatment with γ-T3 and baicalein enhanced the anti-proliferative activity of baicalein, accompanied by the downstream events of AhR-activation induced by baicalein. These data suggest that γ-T3 upregulates AhR expression and enhances its sensitivity to baicalein. - Highlights: • γ-T3 upregulated the expression of AhR in mouse melanoma. • Promotion of the binding activity of Sp1 is associated with the increasing effect of γ-T3 on AhR expression. • γ-T3 enhanced the anti-proliferative activity of baicalein that has an AhR ligand activity. • γ-T3 enhanced the inducing activity of baicalein on the expression of AhR target genes.

  10. Aryl hydrocarbon receptor inhibition promotes hematolymphoid development from human pluripotent stem cells.

    Science.gov (United States)

    Angelos, Mathew G; Ruh, Paige N; Webber, Beau R; Blum, Robert H; Ryan, Caitlin D; Bendzick, Laura; Shim, Seonhui; Yingst, Ashley M; Tufa, Dejene M; Verneris, Michael R; Kaufman, Dan S

    2017-06-29

    The aryl hydrocarbon receptor (AHR) plays an important physiological role in hematopoiesis. AHR is highly expressed in hematopoietic stem and progenitor cells (HSPCs) and inhibition of AHR results in a marked expansion of human umbilical cord blood-derived HSPCs following cytokine stimulation. It is unknown whether AHR also contributes earlier in human hematopoietic development. To model hematopoiesis, human embryonic stem cells (hESCs) were allowed to differentiate in defined conditions in the presence of the AHR antagonist StemReginin-1 (SR-1) or the AHR agonist 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). We demonstrate a significant increase in CD34+CD31+ hematoendothelial cells in SR-1-treated hESCs, as well as a twofold expansion of CD34+CD45+ hematopoietic progenitor cells. Hematopoietic progenitor cells were also significantly increased by SR-1 as quantified by standard hematopoietic colony-forming assays. Using a clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9)-engineered hESC-RUNX1c-tdTomato reporter cell line with AHR deletion, we further demonstrate a marked enhancement of hematopoietic differentiation relative to wild-type hESCs. We also evaluated whether AHR antagonism could promote innate lymphoid cell differentiation from hESCs. SR-1 increased conventional natural killer (cNK) cell differentiation, whereas TCDD treatment blocked cNK development and supported group 3 innate lymphoid cell (ILC3) differentiation. Collectively, these results demonstrate that AHR regulates early human hematolymphoid cell development and may be targeted to enhance production of specific cell populations derived from human pluripotent stem cells. © 2017 by The American Society of Hematology.

  11. Dioxin exposure blocks lactation through a direct effect on mammary epithelial cells mediated by the aryl hydrocarbon receptor repressor.

    Science.gov (United States)

    Basham, Kaitlin J; Leonard, Christopher J; Kieffer, Collin; Shelton, Dawne N; McDowell, Maria E; Bhonde, Vasudev R; Looper, Ryan E; Welm, Bryan E

    2015-01-01

    In mammals, lactation is a rich source of nutrients and antibodies for newborn animals. However, millions of mothers each year experience an inability to breastfeed. Exposure to several environmental toxicants, including 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), has been strongly implicated in impaired mammary differentiation and lactation. TCDD and related polyhalogenated aromatic hydrocarbons are widespread industrial pollutants that activate the aryl hydrocarbon receptor (AHR). Despite many epidemiological and animal studies, the molecular mechanism through which AHR signaling blocks lactation remains unclear. We employed in vitro models of mammary differentiation to recapitulate lactogenesis in the presence of toxicants. We demonstrate AHR agonists directly block milk production in isolated mammary epithelial cells. Moreover, we define a novel role for the aryl hydrocarbon receptor repressor (AHRR) in mediating this response. Our mechanistic studies suggest AHRR is sufficient to block transcription of the milk gene β-casein. As TCDD is a prevalent environmental pollutant that affects women worldwide, our results have important public health implications for newborn nutrition. © The Author 2014. Published by Oxford University Press on behalf of the Society of Toxicology. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  12. Endogenous angiotensin II suppresses stretch-induced ANP secretion via AT1 receptor pathway.

    Science.gov (United States)

    Oh, Young-Bin; Gao, Shan; Shah, Amin; Kim, Jong Hun; Park, Woo Hyun; Kim, Suhn Hee

    2011-02-01

    Angiotensin II (Ang II) is released by stretch of cardiac myocytes and has paracrine and autocrine effects on cardiac myocytes and fibroblasts. However, the direct effect of Ang II on the secretion of atrial natriuretic peptide (ANP) is unclear. The aim of the present study is to test whether Ang II affects stretch-induced ANP secretion. The isolated perfused beating atria were used from control and two-kidney one-clip hypertensive (2K1C) rats. The volume load was achieved by elevating the height of outflow catheter connected with isolated atria from 5cmH(2)O to 7.5cmH(2)O. Atrial stretch by volume load caused increases in atrial contractility by 60% and in ANP secretion by 100%. Ang II suppressed stretch-induced ANP secretion and tended to increase atrial contractility whereas losartan stimulated stretch-induced ANP secretion. Neither PD123319 nor A779 had direct effect on stretch-induced ANP secretion. The suppressive effect of Ang II on stretch-induced ANP secretion was blocked by the pretreatment of losartan but not by the pretreatment of PD123319 or A779. In hypertrophied atria from 2K1C rats, stretch-induced ANP concentration attenuated and atrial contractility augmented. The response of stretch-induced ANP secretion to Ang II and losartan augmented. The expression of AT1 receptor protein and mRNA increased but AT2 and Mas receptor mRNA did not change in 2K1C rat atria. Therefore, we suggest that Ang II generated endogenously by atrial stretch suppresses stretch-induced ANP secretion through the AT1 receptor and alteration of Ang II effect in 2K1C rat may be due to upregulation of AT1 receptor. Copyright © 2010 Elsevier Inc. All rights reserved.

  13. BMPR2 expression is suppressed by signaling through the estrogen receptor

    Directory of Open Access Journals (Sweden)

    Austin Eric D

    2012-02-01

    Full Text Available Abstract Background Studies in multiple organ systems have shown cross-talk between signaling through the bone morphogenetic protein receptor type 2 (BMPR2 and estrogen pathways. In humans, pulmonary arterial hypertension (PAH has a female predominance, and is associated with decreased BMPR2 expression. The goal of this study was to determine if estrogens suppress BMPR2 expression. Methods A variety of techniques were utilized across several model platforms to evaluate the relationship between estrogens and BMPR2 gene expression. We used quantitative RT-PCR, gel mobility shift, and luciferase activity assays in human samples, live mice, and cell culture. Results BMPR2 expression is reduced in lymphocytes from female patients compared with male patients, and in whole lungs from female mice compared with male mice. There is an evolutionarily conserved estrogen receptor binding site in the BMPR2 promoter, which binds estrogen receptor by gel-shift assay. Increased exogenous estrogen decreases BMPR2 expression in cell culture, particularly when induced to proliferate. Transfection of increasing quantities of estrogen receptor alpha correlates strongly with decreasing expression of BMPR2. Conclusions BMPR2 gene expression is reduced in females compared to males in live humans and in mice, likely through direct estrogen receptor alpha binding to the BMPR2 promoter. This reduced BMPR2 expression may contribute to the increased prevalence of PAH in females.

  14. Sigma1 Targeting to Suppress Aberrant Androgen Receptor Signaling in Prostate Cancer.

    Science.gov (United States)

    Thomas, Jeffrey D; Longen, Charles G; Oyer, Halley M; Chen, Nan; Maher, Christina M; Salvino, Joseph M; Kania, Blase; Anderson, Kelsey N; Ostrander, William F; Knudsen, Karen E; Kim, Felix J

    2017-05-01

    Suppression of androgen receptor (AR) activity in prostate cancer by androgen depletion or direct AR antagonist treatment, although initially effective, leads to incurable castration-resistant prostate cancer (CRPC) via compensatory mechanisms including resurgence of AR and AR splice variant (ARV) signaling. Emerging evidence suggests that Sigma1 (also known as sigma-1 receptor) is a unique chaperone or scaffolding protein that contributes to cellular protein homeostasis. We reported previously that some Sigma1-selective small molecules can be used to pharmacologically modulate protein homeostasis pathways. We hypothesized that these Sigma1-mediated responses could be exploited to suppress AR protein levels and activity. Here we demonstrate that treatment with a small-molecule Sigma1 inhibitor prevented 5α- dihydrotestosterone-mediated nuclear translocation of AR and induced proteasomal degradation of AR and ARV, suppressing the transcriptional activity and protein levels of both full-length and splice-variant AR. Consistent with these data, RNAi knockdown of Sigma1 resulted in decreased AR levels and transcriptional activity. Furthermore, Sigma1 physically associated with ARV7 and ARv567es as well as full-length AR. Treatment of mice xenografted with ARV-driven CRPC tumors with a drug-like small-molecule Sigma1 inhibitor significantly inhibited tumor growth associated with elimination of AR and ARV7 in responsive tumors. Together, our data show that Sigma1 modulators can be used to suppress AR/ARV-driven prostate cancer cells via regulation of pharmacologically responsive Sigma1-AR/ARV interactions, both in vitro and in vivoCancer Res; 77(9); 2439-52. ©2017 AACR. ©2017 American Association for Cancer Research.

  15. Suppression of ANP secretion by somatostatin through somatostatin receptor type 2.

    Science.gov (United States)

    Gao, Shan; Oh, Young-bin; Shah, Amin; Park, Woo Hyun; Kim, Suhn Hee

    2011-06-01

    Somatostatin is a cyclic-14 amino acid peptide which mainly distributed in digestive system and brain. Somatostatin receptor (SSTR) is a G-protein coupled receptor and all five SSTR subtypes are expressed in cardiomyocytes. The aim of this study was to investigate the effect of somatostatin on atrial natriuretic peptide (ANP) secretion and its signaling pathway. Somatostatin (0.01 and 0.1nM) decreased ANP secretion in isolated beating rat atrium in a dose-dependent manner. But atrial contractility and translocation of extracellular fluid were not changed. Somatostatin-induced decrease in ANP secretion was significantly attenuated by the pretreatment with CYN 154806 (SSTR type 2 antagonist; 0.1μM), but not by BIM 23056 (SSTR type 5 antagonist; 0.1μM) and urantide (urotensin II receptor antagonist; 0.1μM). When pretreated with an agonist for SSTR type 2 (Seglitide, 0.1nM) and SSTR type 5 (L 817818, 0.1nM), only Seglitide reduced ANP secretion similar to that of somatostatin. The suppressive effect of somatostatin on ANP secretion was attenuated by the pretreatment with an inhibitor for adenylyl cyclase (MDL-12330A, 5μM) or protein kinase A (KT 5720, 0.1μM). In diabetic rat atria, the suppressive effect of somatostatin on ANP secretion and concentration was attenuated. Real time-PCR and western blot shows the decreased level of SSTR type 2 mRNA and protein in diabetic rat atria. These data suggest that somatostatin decreased ANP secretion through SSTR type 2 and an attenuation of suppressive effect of somatostatin on ANP secretion in diabetic rat atria is due to a down-regulation of SSTR type 2. Copyright © 2011 Elsevier Inc. All rights reserved.

  16. Aryl hydrocarbon receptor protects lung adenocarcinoma cells against cigarette sidestream smoke particulates-induced oxidative stress

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Ya-Hsin [Graduate Institute of Basic Medical Science, School of Medicine, China Medical University, Taichung 40402, Taiwan, ROC (China); Huang, Su-Chin; Lin, Chun-Ju; Cheng, Li-Chuan [Division of Environmental Health and Occupational Medicine, National Health Research Institutes, Zhunan, Miaoli 35053, Taiwan, ROC (China); Li, Lih-Ann, E-mail: lihann@nhri.org.tw [Division of Environmental Health and Occupational Medicine, National Health Research Institutes, Zhunan, Miaoli 35053, Taiwan, ROC (China)

    2012-03-15

    Environmental cigarette smoke has been suggested to promote lung adenocarcinoma progression through aryl hydrocarbon receptor (AhR)-signaled metabolism. However, whether AhR facilitates metabolic activation or detoxification in exposed adenocarcinoma cells remains ambiguous. To address this question, we have modified the expression level of AhR in two human lung adenocarcinoma cell lines and examined their response to an extract of cigarette sidestream smoke particulates (CSSP). We found that overexpression of AhR in the CL1-5 cell line reduced CSSP-induced ROS production and oxidative DNA damage, whereas knockdown of AhR expression increased ROS level in CSSP-exposed H1355 cells. Oxidative stress sensor Nrf2 and its target gene NQO1 were insensitive to AhR expression level and CSSP treatment in human lung adenocarcinoma cells. In contrast, induction of AhR expression concurrently increased mRNA expression of xenobiotic-metabolizing genes CYP1B1, UGT1A8, and UGT1A10 in a ligand-independent manner. It appeared that AhR accelerated xenobiotic clearing and diminished associated oxidative stress by coordinate regulation of a set of phase I and II metabolizing genes. However, the AhR-signaled protection could not shield cells from constant oxidative stress. Prolonged exposure to high concentrations of CSSP induced G0/G1 cell cycle arrest via the p53–p21–Rb1 signaling pathway. Despite no effect on DNA repair rate, AhR facilitated the recovery of cells from growth arrest when CSSP exposure ended. AhR-overexpressing lung adenocarcinoma cells exhibited an increased anchorage-dependent and independent proliferation when recovery from exposure. In summary, our data demonstrated that AhR protected lung adenocarcinoma cells against CSSP-induced oxidative stress and promoted post-exposure clonogenicity. -- Highlights: ► AhR expression level influences cigarette sidestream smoke-induced ROS production. ► AhR reduces oxidative stress by coordinate regulation of

  17. RNA Editing Modulates Human Hepatic Aryl Hydrocarbon Receptor Expression by Creating MicroRNA Recognition Sequence.

    Science.gov (United States)

    Nakano, Masataka; Fukami, Tatsuki; Gotoh, Saki; Takamiya, Masataka; Aoki, Yasuhiro; Nakajima, Miki

    2016-01-08

    Adenosine to inosine (A-to-I) RNA editing is the most frequent type of post-transcriptional nucleotide conversion in humans, and it is catalyzed by adenosine deaminase acting on RNA (ADAR) enzymes. In this study we investigated the effect of RNA editing on human aryl hydrocarbon receptor (AhR) expression because the AhR transcript potentially forms double-stranded structures, which are targets of ADAR enzymes. In human hepatocellular carcinoma-derived Huh-7 cells, the ADAR1 knockdown reduced the RNA editing levels in the 3'-untranslated region (3'-UTR) of the AhR transcript and increased the AhR protein levels. The ADAR1 knockdown enhanced the ligand-mediated induction of CYP1A1, a gene downstream of AhR. We investigated the possibility that A-to-I RNA editing creates miRNA targeting sites in the AhR mRNA and found that the miR-378-dependent down-regulation of AhR was abolished by ADAR1 knockdown. These results indicated that the ADAR1-mediated down-regulation of AhR could be attributed to the creation of a miR-378 recognition site in the AhR 3'-UTR. The interindividual differences in the RNA editing levels within the AhR 3'-UTR in a panel of 32 human liver samples were relatively small, whereas the differences in ADAR1 expression were large (220-fold). In the human liver samples a significant inverse association was observed between the miR-378 and AhR protein levels, suggesting that the RNA-editing-dependent down-regulation of AhR by miR-378 contributes to the variability in the constitutive hepatic expression of AhR. In conclusion, this study uncovered for the first time that A-to-I RNA editing modulates the potency of xenobiotic metabolism in the human liver. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

  18. CD81 interacts with the T cell receptor to suppress signaling.

    Directory of Open Access Journals (Sweden)

    Safak Isil Cevik

    Full Text Available CD81 (TAPA-1 is a ubiquitously expressed tetraspanin protein identified as a component of the B lymphocyte receptor (BCR and as a receptor for the Hepatitis C Virus. In an effort to identify trans-membrane proteins that interact with the T-cell antigen receptor (TCR, we performed a membrane yeast two hybrid screen and identified CD81 as an interactor of the CD3delta subunit of the TCR. We found that in the absence of CD81, in thymocytes from knockout mice, TCR engagement resulted in stronger signals. These results were recapitulated in T cell lines that express low levels of CD81 through shRNA mediated silencing. Increased signaling did not result from alterations in the levels of TCR on the surface of T lymphocytes. Although CD81 is not essential for normal T lymphocyte development, it plays an important role in regulating TCR and possibly pre-TCR signal transduction by controlling the strength of signaling. CD81 dependent alterations in thymocyte signaling are evident in increased CD5 expression on CD81 deficient double positive (DP thymocytes. We conclude that CD81 interacts with the T cell receptor to suppress signaling.

  19. Human and rodent aryl hydrocarbon receptor (AHR): from mediator of dioxin toxicity to physiologic AHR functions and therapeutic options.

    Science.gov (United States)

    Bock, Karl Walter

    2017-04-01

    Metabolism of aryl hydrocarbons and toxicity of dioxins led to the discovery of the aryl hydrocarbon receptor (AHR). Tremendous advances have been made on multiplicity of AHR signaling and identification of endogenous ligands including the tryptophan metabolites FICZ and kynurenine. However, human AHR functions are still poorly understood due to marked species differences as well as cell-type- and cell context-dependent AHR functions. Observations in dioxin-poisoned individuals may provide hints to physiologic AHR functions in humans. Based on these observations three human AHR functions are discussed: (1) Chemical defence and homeostasis of endobiotics. The AHR variant Val381 in modern humans leads to reduced AHR affinity to aryl hydrocarbons in comparison with Neanderthals and primates expressing the Ala381 variant while affinity to indoles remains unimpaired. (2) Homeostasis of stem/progenitor cells. Dioxins dysregulate homeostasis in sebocyte stem cells. (3) Modulation of immunity. In addition to microbial defence, AHR may be involved in a 'disease tolerance defence pathway'. Further characterization of physiologic AHR functions may lead to therapeutic options.

  20. RIPK1 binds to vitamin D receptor and decreases vitamin D-induced growth suppression.

    Science.gov (United States)

    Quarni, Waise; Lungchukiet, Panida; Tse, Anfernee; Wang, Pei; Sun, Yuefeng; Kasiappan, Ravi; Wu, Jheng-Yu; Zhang, Xiaohong; Bai, Wenlong

    2017-10-01

    Receptor interacting protein kinase 1 (RIPK1) is an enzyme acting downstream of tumor necrosis factor alpha to control cell survival and death. RIPK1 expression has been reported to cause drug resistance in cancer cells, but so far, no published studies have investigated the role of RIPK1 in vitamin D signaling. In the present study, we investigated whether RIPK1 plays any roles in 1,25-dihydroxyvitamin D3 (1,25D3)-induced growth suppression. In our studies, RIPK1 decreased the transcriptional activity of vitamin D receptor (VDR) in luciferase reporter assays independent of its kinase activity, suggesting a negative role of RIPK1 in 1,25D3 action. RIPK1 also formed a complex with VDR, and deletion analyses mapped the RIPK1 binding region to the C-terminal ligand-binding domain of the VDR. Subcellular fractionation analyses indicated that RIPK1 increased VDR retention in the cytoplasm, which may account for its inhibition of VDR transcriptional activity. Consistent with the reporter analyses, 1,25D3-induced growth suppression was more pronounced in RIPK1-null MEFs and RIPK1-knockdown ovarian cancer cells than in control cells. Our studies have defined RIPK1 as a VDR repressor, projecting RIPK1 depletion as a potential strategy to increase the potency of 1,25D3 and its analogs for cancer intervention. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Cardioprotective Role of Tumor Necrosis Factor Receptor-Associated Factor 2 by Suppressing Apoptosis and Necroptosis.

    Science.gov (United States)

    Guo, Xiaoyun; Yin, Haifeng; Li, Lei; Chen, Yi; Li, Jing; Doan, Jessica; Steinmetz, Rachel; Liu, Qinghang

    2017-08-22

    Programmed cell death, including apoptosis, mitochondria-mediated necrosis, and necroptosis, is critically involved in ischemic cardiac injury, pathological cardiac remodeling, and heart failure progression. Whereas apoptosis and mitochondria-mediated necrosis signaling is well established, the regulatory mechanisms of necroptosis and its significance in the pathogenesis of heart failure remain elusive. We examined the role of tumor necrosis factor receptor-associated factor 2 (Traf2) in regulating myocardial necroptosis and remodeling using genetic mouse models. We also performed molecular and cellular biology studies to elucidate the mechanisms by which Traf2 regulates necroptosis signaling. We identified a critical role for Traf2 in myocardial survival and homeostasis by suppressing necroptosis. Cardiac-specific deletion of Traf2 in mice triggered necroptotic cardiac cell death, pathological remodeling, and heart failure. Plasma tumor necrosis factor α level was significantly elevated in Traf2-deficient mice, and genetic ablation of TNFR1 largely abrogated pathological cardiac remodeling and dysfunction associated with Traf2 deletion. Mechanistically, Traf2 critically regulates receptor-interacting proteins 1 and 3 and mixed lineage kinase domain-like protein necroptotic signaling with the adaptor protein tumor necrosis factor receptor-associated protein with death domain as an upstream regulator and transforming growth factor β-activated kinase 1 as a downstream effector. It is important to note that genetic deletion of RIP3 largely rescued the cardiac phenotype triggered by Traf2 deletion, validating a critical role of necroptosis in regulating pathological remodeling and heart failure propensity. These results identify an important Traf2-mediated, NFκB-independent, prosurvival pathway in the heart by suppressing necroptotic signaling, which may serve as a new therapeutic target for pathological remodeling and heart failure. © 2017 American Heart

  2. Quaking Deficiency Amplifies Inflammation in Experimental Endotoxemia via the Aryl Hydrocarbon Receptor/Signal Transducer and Activator of Transcription 1–NF-κB Pathway

    Directory of Open Access Journals (Sweden)

    Li Wang

    2017-12-01

    Full Text Available Macrophages, characterized by considerable diversity and plasticity, play a crucial role in a broad spectrum of biological processes, including inflammation. However, the molecular mechanisms underlying the diverse phenotypes of macrophages are not well defined. Here, we show that the RNA-binding protein, quaking (QKI, dynamically modulates macrophage polarization states. After lipopolysaccharide (LPS stimulation, QKI-silenced RAW 264.7 cells displayed a pro-inflammatory M1 phenotype characterized by increased expression of iNOS, TNF-α, and IL-6 and decreased expression of anti-inflammatory factors, such as IL-10, found in inflammatory zone (Fizz1, and chitinase-like 3 (Chil3 or Ym1. By contrast, QKI5 overexpression led to a suppressive phenotype resembling M2 macrophages, even under M1 differentiation conditions. Moreover, myeloid-specific QKI-deficient mice tended to be more susceptible to LPS-induced endotoxic shock, while the exogenous transfer of macrophages overexpressing QKI5 exerted a significant improving effect. This improvement corresponded to a higher proportion of M2 macrophages, in line with elevated levels of IL-10, and a decrease in levels of pro-inflammatory mediators, such as IL-6, TNF-α, and IL-1β. Further mechanistic studies disclosed that QKI was a potent inhibitor of the nuclear factor-kappa B (NF-κB pathway, suppressing p65 expression and phosphorylation. Strikingly, reduced expression of the aryl hydrocarbon receptor (Ahr and reduced phosphorylation of signal transducer and activator of transcription 1 in QKI-deficient cells failed to restrain the transcriptional activity of NF-κB and NRL pyrin domain containing 3 (NLRP3 activation, while restoring QKI expression skewed the above M1-like response toward an anti-inflammatory M2 state. Taken together, these findings suggest a role for QKI in restraining overt innate immune responses by regulating the Ahr/STAT1–NF-κB pathway.

  3. Association between polymorphisms in the aryl hydrocarbon receptor repressor gene and disseminated testicular germ cell cancer

    DEFF Research Database (Denmark)

    Brokken, Leon J S; Lundberg-Giwercman, Yvonne; Rajpert-De Meyts, Ewa

    2013-01-01

    incidence of TGCC in some countries. Additionally, there is a strong genetic component that affects susceptibility. However, genetic polymorphisms that have been identified so far only partially explain the risk of TGCC. Many of the persistent environmental pollutants act through the aryl hydrocarbon...

  4. An unusual case of an ACTH-secreting macroadenoma with a germline variant in the aryl hydrocarbon receptor-interacting protein (AIP) gene

    DEFF Research Database (Denmark)

    Dinesen, Pia T; Dal, Jakob; Gabrovska, Plamena

    2015-01-01

    UNLABELLED: A patient of Cushing's disease (CD) characterized by a large tumor and only subtle symptoms of hormonal hypersecretion was examined. The patient had a germline variant in the aryl hydrocarbon receptor-interacting protein (AIP) gene. A 50-year-old male presenting with headache was diag......UNLABELLED: A patient of Cushing's disease (CD) characterized by a large tumor and only subtle symptoms of hormonal hypersecretion was examined. The patient had a germline variant in the aryl hydrocarbon receptor-interacting protein (AIP) gene. A 50-year-old male presenting with headache...

  5. Adeno-associated viral vector-induced overexpression of neuropeptide Y Y2 receptors in the hippocampus suppresses seizures

    DEFF Research Database (Denmark)

    Woldbye, David Paul Drucker; Ängehagen, Mikael; Gøtzsche, Casper René

    2010-01-01

    Gene therapy using recombinant adeno-associated viral vectors overexpressing neuropeptide Y in the hippocampus exerts seizure-suppressant effects in rodent epilepsy models and is currently considered for clinical application in patients with intractable mesial temporal lobe epilepsy. Seizure...... suppression by neuropeptide Y in the hippocampus is predominantly mediated by Y2 receptors, which, together with neuropeptide Y, are upregulated after seizures as a compensatory mechanism. To explore whether such upregulation could prevent seizures, we overexpressed Y2 receptors in the hippocampus using...... recombinant adeno-associated viral vectors. In two temporal lobe epilepsy models, electrical kindling and kainate-induced seizures, vector-based transduction of Y2 receptor complementary DNA in the hippocampus of adult rats exerted seizure-suppressant effects. Simultaneous overexpression of Y2...

  6. Aryl hydrocarbon receptor-dependent regulation of miR-196a expression controls lung fibroblast apoptosis but not proliferation

    Energy Technology Data Exchange (ETDEWEB)

    Hecht, Emelia [Department of Medicine, McGill University, Montreal, Quebec (Canada); Zago, Michela [Research Institute of the McGill University Health Centre, McGill University, Montreal, Quebec (Canada); Sarill, Miles [Department of Medicine, McGill University, Montreal, Quebec (Canada); Rico de Souza, Angela [Research Institute of the McGill University Health Centre, McGill University, Montreal, Quebec (Canada); Gomez, Alvin; Matthews, Jason [Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON (Canada); Hamid, Qutayba; Eidelman, David H. [Department of Medicine, McGill University, Montreal, Quebec (Canada); Research Institute of the McGill University Health Centre, McGill University, Montreal, Quebec (Canada); Baglole, Carolyn J., E-mail: Carolyn.baglole@McGill.ca [Department of Medicine, McGill University, Montreal, Quebec (Canada); Research Institute of the McGill University Health Centre, McGill University, Montreal, Quebec (Canada)

    2014-11-01

    The aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor implicated in the regulation of apoptosis and proliferation. Although activation of the AhR by xenobiotics such as dioxin inhibits the cell cycle and control apoptosis, paradoxically, AhR expression also promotes cell proliferation and survival independent of exogenous ligands. The microRNA (miRNA) miR-196a has also emerged as a regulator of proliferation and apoptosis but a relationship between the AhR and miR-196a is not known. Therefore, we hypothesized that AhR-dependent regulation of endogenous miR-196a expression would promote cell survival and proliferation. Utilizing lung fibroblasts from AhR deficient (AhR{sup −/−}) and wild-type (AhR{sup +/+}) mice, we show that there is ligand-independent regulation of miRNA, including low miR-196a in AhR{sup −/−} cells. Validation by qRT-PCR revealed a significant decrease in basal expression of miR-196a in AhR{sup −/−} compared to AhR{sup +/+} cells. Exposure to AhR agonists benzo[a]pyrene (B[a]P) and FICZ as well as AhR antagonist CH-223191 decreased miR-196a expression in AhR{sup +/+} fibroblasts concomitant with decreased AhR protein levels. There was increased proliferation only in AhR{sup +/+} lung fibroblasts in response to serum, corresponding to a decrease in p27{sup KIP1} protein, a cyclin-dependent kinase inhibitor. Increasing the cellular levels of miR-196a had no effect on proliferation or expression of p27{sup KIP1} in AhR{sup −/−} fibroblasts but attenuated cigarette smoke-induced apoptosis. This study provides the first evidence that AhR expression is essential for the physiological regulation of cellular miRNA levels- including miR-196a. Future experiments designed to elucidate the functional relationship between the AhR and miR-196a may delineate additional novel ligand-independent roles for the AhR. - Highlights: • The AhR controls proliferation and apoptosis in lung cells. • The AhR regulates the

  7. Augmented Growth Hormone Secretion and Stat3 Phosphorylation in an Aryl Hydrocarbon Receptor Interacting Protein (AIP-Disrupted Somatotroph Cell Line.

    Directory of Open Access Journals (Sweden)

    Takashi Fukuda

    Full Text Available Aryl hydrocarbon receptor interacting protein (AIP is thought to be a tumor suppressor gene, as indicated by a mutational analysis of pituitary somatotroph adenomas. However, the physiological significance of AIP inactivation in somatotroph cells remains unclear. Using CRISPR/Cas9, we identified a GH3 cell clone (termed GH3-FTY in which Aip was genetically disrupted, and subsequently investigated its character with respect to growth hormone (Gh synthesis and proliferation. Compared with GH3, GH3-FTY cells showed remarkably increased Gh production and a slight increase in cell proliferation. Gh-induced Stat3 phosphorylation is known to be a mechanism of Gh oversecretion in GH3. Interestingly, phosphorylated-Stat3 expression in GH3-FTY cells was increased more compared with GH3 cells, suggesting a stronger drive for this mechanism in GH3-FTY. The phenotypes of GH3-FTY concerning Gh overproduction, cell proliferation, and increased Stat3 phosphorylation were significantly reversed by the exogenous expression of Aip. GH3-FTY cells were less sensitive to somatostatin than GH3 cells in the suppression of cell proliferation, which might be associated with the reduced expression of somatostatin receptor type 2. GH3-FTY xenografts in BALB/c nude mice (GH3-FTY mice formed more mitotic somatotroph tumors than GH3 xenografts (GH3 mice, as also evidenced by increased Ki67 scores. GH3-FTY mice were also much larger and had significantly higher plasma Gh levels than GH3 mice. Furthermore, GH3-FTY mice showed relative insulin resistance compared with GH3 mice. In conclusion, we established a somatotroph cell line, GH3-FTY, which possessed prominent Gh secretion and mitotic features associated with the disruption of Aip.

  8. Suppression of TLR4-mediated inflammatory response by macrophage class A scavenger receptor (CD204)

    Energy Technology Data Exchange (ETDEWEB)

    Ohnishi, Koji; Komohara, Yoshihiro; Fujiwara, Yukio; Takemura, Kenichi [Department of Cell Pathology, Graduate School of Medical Sciences, Faculty of Life Sciences, Kumamoto University, Kumamoto (Japan); Lei, XiaoFeng [Department of Cell Pathology, Graduate School of Medical Sciences, Faculty of Life Sciences, Kumamoto University, Kumamoto (Japan); Department of Biochemistry, Showa University School of Medicine, Tokyo (Japan); Nakagawa, Takenobu [Department of Cell Pathology, Graduate School of Medical Sciences, Faculty of Life Sciences, Kumamoto University, Kumamoto (Japan); Sakashita, Naomi [Department of Cell Pathology, Graduate School of Medical Sciences, Faculty of Life Sciences, Kumamoto University, Kumamoto (Japan); Department of Human Pathology, Institute of Health Biosciences, The University of Tokushima, Tokushima (Japan); Takeya, Motohiro, E-mail: takeya@kumamoto-u.ac.jp [Department of Cell Pathology, Graduate School of Medical Sciences, Faculty of Life Sciences, Kumamoto University, Kumamoto (Japan)

    2011-08-05

    Highlights: {yields} We focused on the interaction between SR-A and TLR4 signaling in this study. {yields} SR-A deletion promoted NF{kappa}B activation in macrophages in septic model mouse. {yields} SR-A suppresses both MyD88-dependent and -independent TLR4 signaling in vitro. {yields} SR-A clears LPS binding to TLR4 which resulting in the suppression of TLR4 signals. -- Abstract: The class A scavenger receptor (SR-A, CD204), one of the principal receptors expressed on macrophages, has been found to regulate inflammatory response and attenuate septic endotoxemia. However, the detailed mechanism of this process has not yet been well characterized. To clarify the regulative mechanisms of lipopolysaccharide (LPS)-induced macrophage activation by SR-A, we evaluated the activation of Toll-like receptor 4 (TLR4)-mediated signaling molecules in SR-A-deficient (SR-A{sup -/-}) macrophages. In a septic shock model, the blood levels of tumor necrosis factor (TNF)-{alpha}, interleukin (IL)-6 and interferon (IFN)-{beta} were significantly increased in SR-A{sup -/-} mice compared to wild-type mice, and elevated nuclear factor kappa B (NF{kappa}B) activation was detected in SR-A{sup -/-} macrophages. SR-A deletion increased the production of pro-inflammatory cytokines, and the phosphorylation of mitogen-activated protein kinase (MAPK) and NF{kappa}B in vitro. SR-A deletion also promoted the nuclear translocation of NF{kappa}B and IFN regulatory factor (IRF)-3. In addition, a competitive binding assay with acetylated low-density lipoprotein, an SR-A-specific ligand, and anti-SR-A antibody induced significant activation of TLR4-mediated signaling molecules in wild-type macrophages but not in SR-A{sup -/-} macrophages. These results suggest that SR-A suppresses the macrophage activation by inhibiting the binding of LPS to TLR4 in a competitive manner and it plays a pivotal role in the regulation of the LPS-induced inflammatory response.

  9. Cardiac toxicity of 5-ring polycyclic aromatic hydrocarbons is differentially dependent on the aryl hydrocarbon receptor 2 isoform during zebrafish development

    Energy Technology Data Exchange (ETDEWEB)

    Incardona, John P., E-mail: john.incardona@noaa.gov; Linbo, Tiffany L.; Scholz, Nathaniel L.

    2011-12-15

    Petroleum-derived compounds, including polycyclic aromatic hydrocarbons (PAHs), commonly occur as complex mixtures in the environment. Recent studies using the zebrafish experimental model have shown that PAHs are toxic to the embryonic cardiovascular system, and that the severity and nature of this developmental cardiotoxicity varies by individual PAH. In the present study we characterize the toxicity of the relatively higher molecular weight 5-ring PAHs benzo[a]pyrene (BaP), benzo[e]pyrene (BeP), and benzo[k]fluoranthene (BkF). While all three compounds target the cardiovascular system, the underlying role of the ligand-activated aryl hydrocarbon receptor (AHR2) and the tissue-specific induction of the cytochrome p450 metabolic pathway (CYP1A) were distinct for each. BaP exposure (40 {mu}M) produced AHR2-dependent bradycardia, pericardial edema, and myocardial CYP1A immunofluorescence. By contrast, BkF exposure (4-40 {mu}M) caused more severe pericardial edema, looping defects, and erythrocyte regurgitation through the atrioventricular valve that were AHR2-independent (i.e., absent myocardial or endocardial CYP1A induction). Lastly, exposure to BeP (40 {mu}M) yielded a low level of CYP1A+ signal in the vascular endothelium of the head and trunk, without evident toxic effects on cardiac function or morphogenesis. Combined with earlier work on 3- and 4-ring PAHs, our findings provide a more complete picture of how individual PAHs may drive the cardiotoxicity of mixtures in which they predominate. This will improve toxic injury assessments and risk assessments for wild fish populations that spawn in habitats altered by overlapping petroleum-related human impacts such as oil spills, urban stormwater runoff, or sediments contaminated by legacy industrial activities. -- Highlights: Black-Right-Pointing-Pointer PAH compounds with 5 rings in different arrangements caused differential tissue-specific patterns of CYP1A induction in zebrafish embryos. Black

  10. Assessment of the aryl hydrocarbon receptor-mediated activities of polycyclic aromatic hydrocarbons in a human cell-based reporter gene assay.

    Science.gov (United States)

    Vondráček, Jan; Pěnčíková, Kateřina; Neča, Jiří; Ciganek, Miroslav; Grycová, Aneta; Dvořák, Zdeněk; Machala, Miroslav

    2017-01-01

    Activation of the aryl hydrocarbon receptor (AhR)-mediated activity is one of key events in toxicity of polycyclic aromatic hydrocarbons (PAHs). Although various classes of AhR ligands may differentially activate human and rodent AhR, there is presently a lack of data on the human AhR-inducing relative potencies (REPs) of PAHs. Here, we focused on estimation of the AhR-mediated activities of a large set of environmental PAHs in human gene reporter AZ-AhR cell line, with an aim to develop the human AhR-based REP values with potential implications for risk assessment of PAHs. The previously identified weakly active PAHs mostly failed to activate the AhR in human cells. The order for REPs of individual PAHs in human cells largely corresponded with the available data from rodent-based experimental systems; nevertheless, we identified differences up to one order of magnitude in REP values of PAHs between human and rodent cells. Higher REP values were found in human cells for some important environmental contaminants or suspected carcinogens, such as indeno[1,2,3-cd]pyrene, benz[a]anthracene or benzo[b]fluoranthene, while lower REP values were determined for methyl-substituted PAHs. Our results also indicate that a different rate of metabolism for individual PAHs in human vs. rodent cells may affect estimation of REP values in human cell-based assay, and potentially alter toxicity of some compounds, such as benzofluoranthenes, in humans. We applied the AZ-AhR assay to evaluation of the AhR-mediated activity of complex mixtures of organic compounds associated with diesel exhaust particles, and we identified the polar compounds present in these mixtures as being particularly highly active in human cells, as compared with rodent cells. The present data suggest that differences may exist between the AhR-mediated potencies of PAHs in human and rodent cells, and that the AhR-mediated effects of polar PAH derivatives and metabolites in human cell models deserve further

  11. Inverse agonistic activity of antihistamines and suppression of histamine H1 receptor gene expression.

    Science.gov (United States)

    Mizuguchi, Hiroyuki; Ono, Shohei; Hattori, Masashi; Fukui, Hiroyuki

    2012-01-01

    Histamine H(1) receptor (H1R) expression influences the severity of allergy symptoms. We examined the effect of inverse agonists on H1R gene expression. Two inverse agonists (carebastine and mepyramine), but not the neutral antagonist oxatomide, decreased inositol phosphate accumulation. The inverse agonists also decreased H1R gene expression and down-regulated H1R mRNA below basal expression, while basal H1R mRNA expression was maintained after oxatomide treatment. These results suggest that inverse agonists more potently alleviate allergy symptoms by not only inhibiting stimulus-induced up-regulation of H1R gene expression but also by suppressing basal histamine signaling through their inverse agonistic activity.

  12. Piperlongumine inhibits atherosclerotic plaque formation and vascular smooth muscle cell proliferation by suppressing PDGF receptor signaling

    Energy Technology Data Exchange (ETDEWEB)

    Son, Dong Ju [Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA (United States); Division of Cardiology, Department of Medicine, Emory University, Atlanta, GA (United States); Kim, Soo Yeon [Division of Life Science, Korea Basic Science Institute, Daejeon (Korea, Republic of); Han, Seong Su [University of Iowa Carver College of Medicine, Department of Pathology, Iowa City, IA (United States); Kim, Chan Woo [Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA (United States); Division of Cardiology, Department of Medicine, Emory University, Atlanta, GA (United States); Department of Bioinspired Science, Ehwa Womans University, Seoul (Korea, Republic of); Kumar, Sandeep [Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA (United States); Division of Cardiology, Department of Medicine, Emory University, Atlanta, GA (United States); Park, Byeoung Soo [Nanotoxtech Co., Ansan (Korea, Republic of); Lee, Sung Eun [Division of Applied Biology and Chemistry, Kyungpook National University, Daegu (Korea, Republic of); Yun, Yeo Pyo [College of Pharmacy, Chungbuk National University, Cheongju (Korea, Republic of); Jo, Hanjoong, E-mail: hjo@emory.edu [Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA (United States); Division of Cardiology, Department of Medicine, Emory University, Atlanta, GA (United States); Department of Bioinspired Science, Ehwa Womans University, Seoul (Korea, Republic of); Park, Young Hyun, E-mail: pyh012@sch.ac.kr [Department of Food Science and Nutrition, College of Natural Sciences, Soonchunhyang University, Asan (Korea, Republic of)

    2012-10-19

    Highlights: Black-Right-Pointing-Pointer Anti-atherogenic effect of PL was examined using partial carotid ligation model in ApoE KO mice. Black-Right-Pointing-Pointer PL prevented atherosclerotic plaque development, VSMCs proliferation, and NF-{kappa}B activation. Black-Right-Pointing-Pointer Piperlongumine reduced vascular smooth muscle cell activation through PDGF-R{beta} and NF-{kappa}B-signaling. Black-Right-Pointing-Pointer PL may serve as a new therapeutic molecule for atherosclerosis treatment. -- Abstract: Piperlongumine (piplartine, PL) is an alkaloid found in the long pepper (Piper longum L.) and has well-documented anti-platelet aggregation, anti-inflammatory, and anti-cancer properties; however, the role of PL in prevention of atherosclerosis is unknown. We evaluated the anti-atherosclerotic potential of PL in an in vivo murine model of accelerated atherosclerosis and defined its mechanism of action in aortic vascular smooth muscle cells (VSMCs) in vitro. Local treatment with PL significantly reduced atherosclerotic plaque formation as well as proliferation and nuclear factor-kappa B (NF-{kappa}B) activation in an in vivo setting. PL treatment in VSMCs in vitro showed inhibition of migration and platelet-derived growth factor BB (PDGF-BB)-induced proliferation to the in vivo findings. We further identified that PL inhibited PDGF-BB-induced PDGF receptor beta activation and suppressed downstream signaling molecules such as phospholipase C{gamma}1, extracellular signal-regulated kinases 1 and 2 and Akt. Lastly, PL significantly attenuated activation of NF-{kappa}B-a downstream transcriptional regulator in PDGF receptor signaling, in response to PDGF-BB stimulation. In conclusion, our findings demonstrate a novel, therapeutic mechanism by which PL suppresses atherosclerosis plaque formation in vivo.

  13. Triton X-100 inhibits agonist-induced currents and suppresses benzodiazepine modulation of GABA(A) receptors in Xenopus oocytes

    DEFF Research Database (Denmark)

    Søgaard, Rikke; Ebert, Bjarke; Klaerke, Dan

    2009-01-01

    effects on gramicidin channel A appearance rate and lifetime in artificial lipid bilayers. In the present study, the pharmacological action of Triton-X 100 on GABA(A) receptors expressed in Xenopus laevis oocytes was examined. Triton-X 100 inhibited GABA(A) alpha(1)beta(3)gamma(2S) receptor currents...... by flunitrazepam at alpha(1)beta(3)gamma(2S) receptors. All effects were independent of the presence of a gamma(2S) subunit in the GABA(A) receptor complex. The present study suggests that Triton X-100 may stabilize open and desensitized states of the GABA(A) receptor through changes in lipid bilayer elasticity....... in a noncompetitive, time- and voltage-dependent manner and increased the apparent rate and extent of desensitization at 10 muM, which is 30 fold below the critical micelle concentration. In addition, Triton X-100 induced picrotoxin-sensitive GABA(A) receptor currents and suppressed allosteric modulation...

  14. Non-canonical Glucocorticoid Receptor Transactivation of gilz by Alcohol Suppresses Cell Inflammatory Response

    Directory of Open Access Journals (Sweden)

    Hang Pong Ng

    2017-06-01

    Full Text Available Acute alcohol exposure suppresses cell inflammatory response. The underlying mechanism has not been fully defined. Here we report that alcohol was able to activate glucocorticoid receptor (GR signaling in the absence of glucocorticoids (GCs and upregulated glucocorticoid-induced leucine zipper (gilz, a prominent GC-responsive gene. Such a non-canonical activation of GR was not blocked by mifepristone, a potent GC competitor. The proximal promoter of gilz, encompassing five GC-responsive elements (GREs, was incorporated and tested in a luciferase reporter system. Deletion and/or mutation of the GREs abrogated the promoter responsiveness to alcohol. Thus, the GR–GRE interaction transduced the alcohol action on gilz. Alcohol induced GR nuclear translocation, which was enhanced by the alcohol dehydrogenase inhibitor fomepizole, suggesting that it was alcohol, not its metabolites, that engendered the effect. Gel mobility shift assay showed that unliganded GR was able to bind GREs and such interaction withstood clinically relevant levels of alcohol. GR knockout via CRISPR/Cas9 gene targeting or GILZ depletion via small RNA interference diminished alcohol suppression of cell inflammatory response to LPS. Thus, a previously unrecognized, non-canonical GR activation of gilz is involved in alcohol modulation of cell immune response.

  15. Striatal dopamine D1 receptor suppression impairs reward-associative learning.

    Science.gov (United States)

    Higa, Kerin K; Young, Jared W; Ji, Baohu; Nichols, David E; Geyer, Mark A; Zhou, Xianjin

    2017-04-14

    Dopamine (DA) is required for reinforcement learning. Hence, disruptions in DA signaling may contribute to the learning deficits associated with psychiatric disorders. The DA D1 receptor (D1R) has been linked to learning and is a target for cognitive/motivational enhancement in patients with schizophrenia. Separating the striatal D1R contribution to learning vs. motivation, however, has been challenging. We suppressed striatal D1R expression in mice using a D1R-targeting short hairpin RNA (shRNA), delivered locally to the striatum via an adeno-associated virus (AAV). We then assessed reward- and punishment-associative learning using a probabilistic learning task and motivation using a progressive-ratio breakpoint procedure. We confirmed suppression of striatal D1Rs immunohistochemically and by testing locomotor activity after the administration of (+)-doxanthrine, a full D1R agonist, in control mice and those treated with the D1RshRNA. D1RshRNA-treated mice exhibited impaired reward-associative learning, while punishment-associative learning was spared. This deficit was unrelated to general learning impairments or amotivation, because the D1shRNA-treated mice exhibited normal Barnes maze learning and normal motivation in the progressive-ratio breakpoint procedure. Suppression of striatal D1Rs selectively impaired reward-associative learning whereas punishment-associative learning, aversion-motivated learning, and appetitive motivation were spared. Because patients with schizophrenia exhibit similar reward-associative learning deficits, D1R-targeted treatments should be investigated to improve reward learning in these patients. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. MicroRNA-181a suppresses mouse granulosa cell proliferation by targeting activin receptor IIA.

    Directory of Open Access Journals (Sweden)

    Qun Zhang

    Full Text Available Activin, a member of the transforming growth factor-β superfamily, promotes the growth of preantral follicles and the proliferation of granulosa cells. However, little is known about the role of microRNAs in activin-mediated granulosa cell proliferation. Here, we reported a dose- and time-dependent suppression of microRNA-181a (miR-181a expression by activin A in mouse granulosa cells (mGC. Overexpression of miR-181a in mGC suppressed activin receptor IIA (acvr2a expression by binding to its 3'-untranslated region (3'-UTR, resulting in down-regulation of cyclin D2 and proliferating cell nuclear antigen expression, leading to inhibition of the cellular proliferation, while overexpression of acvr2a attenuated the suppressive effect of miR-181a on mGC proliferation. Consistent with the inhibition of acvr2a expression, miR-181a prevented the phosphorylation of the activin intracellular signal transducer, mothers against decapentaplegic homolog 2 (Smad2, leading to the inactivation of activin signaling pathway. Interestingly, we found that miR-181a expression decreased in ovaries of mice at age of 8, 12, and 21 days, as compared with that in ovaries of 3-day old mice, and its level was reduced in preantral and antral follicles of mice compared with that in primary ones. Moreover, the level of miR-181a in the blood of patients with premature ovarian failure was significantly increased compared with that in normal females. This study identifies an interplay between miR-181a and acvr2a, and reveals an important role of miR-181a in regulating granulosa cell proliferation and ovarian follicle development.

  17. Receptor modeling of C2─C7 hydrocarbon sources at an urban background site in Zurich, Switzerland: changes between 1993─1994 and 2005─2006

    Directory of Open Access Journals (Sweden)

    S. Reimann

    2008-05-01

    Full Text Available Hourly measurements of 13 volatile hydrocarbons (C2–C7 were performed at an urban background site in Zurich (Switzerland in the years 1993–1994 and again in 2005–2006. For the separation of the volatile organic compounds by gas-chromatography (GC, an identical chromatographic column was used in both campaigns. Changes in hydrocarbon profiles and source strengths were recovered by positive matrix factorization (PMF. Eight and six factors could be related to hydrocarbon sources in 1993–1994 and in 2005–2006, respectively. The modeled source profiles were verified by hydrocarbon profiles reported in the literature. The source strengths were validated by independent measurements, such as inorganic trace gases (NOx, CO, SO2, methane (CH4, oxidized hydrocarbons (OVOCs and meteorological data (temperature, wind speed etc.. Our analysis suggests that the contribution of most hydrocarbon sources (i.e. road traffic, solvents use and wood burning decreased by a factor of about two to three between the early 1990s and 2005–2006. On the other hand, hydrocarbon losses from natural gas leakage remained at relatively constant levels (−20%. The estimated emission trends are in line with the results from different receptor-based approaches reported for other European cities. Their differences to national emission inventories are discussed.

  18. Gene-environment interactions in male reproductive health: special reference to the aryl hydrocarbon receptor signaling pathway

    Directory of Open Access Journals (Sweden)

    Leon J S Brokken

    2014-02-01

    Full Text Available Over the last few decades, there have been numerous reports of adverse effects on the reproductive health of wildlife and laboratory animals caused by exposure to endocrine disrupting chemicals (EDCs. The increasing trends in human male reproductive disorders and the mounting evidence for causative environmental factors have therefore sparked growing interest in the health threat posed to humans by EDCs, which are substances in our food, environment and consumer items that interfere with hormone action, biosynthesis or metabolism, resulting in disrupted tissue homeostasis or reproductive function. The mechanisms of EDCs involve a wide array of actions and pathways. Examples include the estrogenic, androgenic, thyroid and retinoid pathways, in which the EDCs may act directly as agonists or antagonists, or indirectly via other nuclear receptors. Dioxins and dioxin-like EDCs exert their biological and toxicological actions through activation of the aryl hydrocarbon-receptor, which besides inducing transcription of detoxifying enzymes also regulates transcriptional activity of other nuclear receptors. There is increasing evidence that genetic predispositions may modify the susceptibility to adverse effects of toxic chemicals. In this review, potential consequences of hereditary predisposition and EDCs are discussed, with a special focus on the currently available publications on interactions between dioxin and androgen signaling.

  19. Aryl hydrocarbon receptor mediated activities in road dust from a metropolitan area, Hanoi-Vietnam: contribution of polycyclic aromatic hydrocarbons (PAHs) and human risk assessment.

    Science.gov (United States)

    Tuyen, Le Huu; Tue, Nguyen Minh; Suzuki, Go; Misaki, Kentaro; Viet, Pham Hung; Takahashi, Shin; Tanabe, Shinsuke

    2014-09-01

    Dioxin-Responsive Chemical-Activated LUciferase gene eXpression assay (DR-CALUX) was applied to assess the total toxic activity of the mixture of PAHs and related compounds as well as dioxin-related compounds in road dust from urban areas of Hanoi, Vietnam. Road dust from Hanoi contained significantly higher DR-CALUX activities (3 to 39, mean 20 ng CALUX-TEQ/g dw) than those from a rural site (2 to 13, mean 5 ng CALUX-TEQ/g dw). The total concentrations of 24 major PAHs (Σ24PAHs) in urban road dust (0.1 to 5.5, mean 2.5 μg/g dw) were also 6 times higher than those in rural road dust (0.08 to 1.5, mean 0.4 μg/g dw). Diagnostic ratios of PAHs indicated vehicular engine combustion as the major PAH emission source in both sites. PAHs accounted for 0.8 to 60% (mean 10%) and 2 to 76% (mean 20%) of the measured CALUX-TEQs in road dust for Hanoi the rural site, respectively. Benzo[b]-/benzo[k]fluoranthenes were the major TEQ contributors among PAHs, whereas DRCs contributed hydrocarbon receptor agonists in road dust. Significant PAH concentrations in urban dust indicated high mutagenic and carcinogenic potencies. Estimated results of incremental life time cancer risk (ILCR) indicated that Vietnamese populations, especially those in urban areas such as Hanoi, are potentially exposed to high cancer risk via both dust ingestion and dermal contact. This is the first study on the exposure risk of AhR agonists, including PAHs and DRCs, in urban road dust from a developing country using a combined bio-chemical analytical approach. Copyright © 2014 Elsevier B.V. All rights reserved.

  20. RETRACTED: Quercetin suppresses insulin receptor signaling through inhibition of the insulin ligand-receptor binding and therefore impairs cancer cell proliferation.

    Science.gov (United States)

    Wang, Feng; Yang, Yong

    2014-10-03

    Although the flavonoid quercetin is known to inhibit activation of insulin receptor signaling, the inhibitory mechanism is largely unknown. In this study, we demonstrate that quercetin suppresses insulin induced dimerization of the insulin receptor (IR) through interfering with ligand-receptor interactions, which reduces the phosphorylation of IR and Akt. This inhibitory effect further inhibits insulin stimulated glucose uptake due to decreased cell membrane translocation of glucose transporter 4 (GLUT4), resulting in impaired cancer cell proliferation. The effect of quercetin in inhibiting tumor growth was also evident in an in vivo model, indicating a potential future application for quercetin in the treatment of cancers. Copyright © 2014 Elsevier Inc. All rights reserved.

  1. Decoy Receptor 3 Improves Survival in Experimental Sepsis by Suppressing the Inflammatory Response and Lymphocyte Apoptosis.

    Directory of Open Access Journals (Sweden)

    DongYu Liang

    Full Text Available Unbalanced inflammatory response and lymphocyte apoptosis is associated with high mortality in septic patients. Decoy receptor 3 (DcR3, a member of the tumor necrosis factor receptor superfamily, is an anti-inflammatory and anti-apoptotic factor. Recently, DcR3 expression was found to be increased in septic patients. This study evaluated the therapeutic effect and mechanisms of DcR3 on cecal ligation and puncture (CLP-induced sepsis in mice.C57BL/6 mice were subjected to CLP-induced polymicrobial sepsis. DcR3 Fc was intravenously injected 30 min before and 6 h after CLP. Bacterial clearance, cytokine production, histology, lymphocyte apoptosis and survival were evaluated. Furthermore, we investigated the systemic effects of DcR3 in in vitro lymphocyte apoptosis regulation.Our results demonstrated that DcR3 protein treatments significantly improved survival in septic mice (p <0.05. Treatment with DcR3 protein significantly reduced the inflammatory response and decreased lymphocyte apoptosis in the thymus and spleen. Histopathological findings of the lung and liver showed milder impairment after DcR3 administration. In vitro experiments showed that DcR3 Fc inhibited Fas-FasL mediated lymphocyte apoptosis.Treatment with the DcR3 protein protects mice from sepsis by suppressing the inflammatory response and lymphocyte apoptosis. DcR3 protein may be useful in treatment of sepsis.

  2. Evodia alkaloids suppress gluconeogenesis and lipogenesis by activating the constitutive androstane receptor.

    Science.gov (United States)

    Yu, Lushan; Wang, Zhangting; Huang, Minmin; Li, Yingying; Zeng, Kui; Lei, Jinxiu; Hu, Haihong; Chen, Baian; Lu, Jing; Xie, Wen; Zeng, Su

    2016-09-01

    The constitutive androstane receptor (CAR) is a key sensor in xenobiotic detoxification and endobiotic metabolism. Increasing evidence suggests that CAR also plays a role in energy metabolism by suppressing the hepatic gluconeogenesis and lipogenesis. In this study, we investigated the effects of two evodia alkaloids, rutaecarpine (Rut) and evodiamine (Evo), on gluconeogenesis and lipogenesis through their activation of the human CAR (hCAR). We found that both Rut and Evo exhibited anti-lipogenic and anti-gluconeogenic effects in the hyperlipidemic HepG2 cells. Both compounds can potently activate hCAR, and treatment of cells with hCAR antagonists reversed the anti-lipogenic and anti-gluconeogenic effects of Rut and Evo. The anti-gluconeogenic effect of Rut and Evo was due to the CAR-mediated inhibition of the recruitment of forkhead box O1 (FoxO1) and hepatocyte nuclear factor 4α (HNF4α) onto the phosphoenolpyruvate carboxykinase (PEPCK) and glucose-6-phosphatase (G6Pase) gene promoters. In vivo, we showed that treatment of mice with Rut improved glucose tolerance in a CAR-dependent manner. Our results suggest that the evodia alkaloids Rut and Evo may have a therapeutic potential for the treatment of hyperglycemia and type 2 diabetes. This article is part of a Special Issue entitled: Xenobiotic nuclear receptors: New Tricks for An Old Dog, edited by Dr. Wen Xie. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. 6-Formylindolo[3,2-b]Carbazole Accelerates Skin Wound Healing via Activation of ERK, but Not Aryl Hydrocarbon Receptor.

    Science.gov (United States)

    Morino-Koga, Saori; Uchi, Hiroshi; Mitoma, Chikage; Wu, Zhouwei; Kiyomatsu, Mari; Fuyuno, Yoko; Nagae, Konosuke; Yasumatsu, Mao; Suico, Mary Ann; Kai, Hirofumi; Furue, Masutaka

    2017-10-01

    Wound healing is an elaborate process composed of overlapping phases, such as proliferation and remodeling, and is delayed in several circumstances, including diabetes. Although several treatment strategies for chronic wounds, such as growth factors, have been applied, further alternatives are required. The skin, especially keratinocytes, is continually exposed to UV rays, which impairs wound healing. 6-Formylindolo[3,2-b]carbazole (FICZ) is a tryptophan photoproduct formed by UV exposure, indicating that FICZ might be one of the effectors of UV radiation. In contrast, treatment with tryptophan, the precursor for FICZ, promoted wound closure in keratinocytes. Therefore, the aim of our study was to determine the role of FICZ in wound healing. Here we showed that FICZ enhanced keratinocyte migration through mitogen-activated protein kinase/extracellular signal-regulated kinase activation, and promoted wound healing in various mouse models, including db/db mice, which exhibit wound healing impairments because of type 2 diabetes. Moreover, FICZ, the endogenous ligand of an aryl hydrocarbon receptor, accelerated migration even in the aryl hydrocarbon receptor knockdown condition and also promoted wound healing in DBA/2 mice, bearing a low-affinity aryl hydrocarbon receptor, suggesting that FICZ enhanced keratinocyte migration in a mitogen-activated protein kinase/extracellular signal-regulated kinase-dependent, but aryl hydrocarbon receptor-independent, manner. The function of FICZ might indicate the possibility of its clinical use for intractable chronic wounds. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  4. Antioxidants for Healthy Skin: The Emerging Role of Aryl Hydrocarbon Receptors and Nuclear Factor-Erythroid 2-Related Factor-2.

    Science.gov (United States)

    Furue, Masutaka; Uchi, Hiroshi; Mitoma, Chikage; Hashimoto-Hachiya, Akiko; Chiba, Takahito; Ito, Takamichi; Nakahara, Takeshi; Tsuji, Gaku

    2017-03-03

    Skin is the outermost part of the body and is, thus, inevitably exposed to UV rays and environmental pollutants. Oxidative stress by these hazardous factors accelerates skin aging and induces skin inflammation and carcinogenesis. Aryl hydrocarbon receptors (AHRs) are chemical sensors that are abundantly expressed in epidermal keratinocytes and mediate the production of reactive oxygen species. To neutralize or minimize oxidative stress, the keratinocytes also express nuclear factor-erythroid 2-related factor-2 (NRF2), which is a master switch for antioxidant signaling. Notably, there is fine-tuned crosstalk between AHR and NRF2, which mutually increase or decrease their activation states. Many NRF2-mediated antioxidant phytochemicals are capable of up- and downmodulating AHR signaling. The precise mechanisms by which these phytochemicals differentially affect the AHR and NRF2 system remain largely unknown and warrant future investigation.

  5. Aspirin suppresses cardiac fibroblast proliferation and collagen formation through downregulation of angiotensin type 1 receptor transcription

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xianwei, E-mail: XWang2@UAMS.edu; Lu, Jingjun; Khaidakov, Magomed; Mitra, Sona; Ding, Zufeng; Raina, Sameer; Goyal, Tanu; Mehta, Jawahar L., E-mail: MehtaJL@UAMS.edu

    2012-03-15

    Aspirin (acetyl salicylic acid, ASA) is a common drug used for its analgesic and antipyretic effects. Recent studies show that ASA not only blocks cyclooxygenase, but also inhibits NADPH oxidase and resultant reactive oxygen species (ROS) generation, a pathway that underlies pathogenesis of several ailments, including hypertension and tissue remodeling after injury. In these disease states, angiotensin II (Ang II) activates NADPH oxidase via its type 1 receptor (AT1R) and leads to fibroblast growth and collagen synthesis. In this study, we examined if ASA would inhibit NADPH oxidase activation, upregulation of AT1R transcription, and subsequent collagen generation in mouse cardiac fibroblasts challenged with Ang II. Mouse heart fibroblasts were isolated and treated with Ang II with or without ASA. As expected, Ang II induced AT1R expression, and stimulated cardiac fibroblast growth and collagen synthesis. The AT1R blocker losartan attenuated these effects of Ang II. Similarly to losartan, ASA, and its SA moiety suppressed Ang II-mediated AT1R transcription and fibroblast proliferation as well as expression of collagens and MMPs. ASA also suppressed the expression of NADPH oxidase subunits (p22{sup phox}, p47{sup phox}, p67{sup phox}, NOX2 and NOX4) and ROS generation. ASA did not affect total NF-κB p65, but inhibited its phosphorylation and activation. These observations suggest that ASA inhibits Ang II-induced NADPH oxidase expression, NF-κB activation and AT1R transcription in cardiac fibroblasts, and fibroblast proliferation and collagen expression. The critical role of NADPH oxidase activity in stimulation of AT1R transcription became apparent in experiments where ASA also inhibited AT1R transcription in cardiac fibroblasts challenged with H{sub 2}O{sub 2}. Since SA had similar effect as ASA on AT1R expression, we suggest that ASA's effect is mediated by its SA moiety. -- Highlights: ► Aspirin in therapeutic concentrations decreases mouse cardiac

  6. Dibutyltin disrupts glucocorticoid receptor function and impairs glucocorticoid-induced suppression of cytokine production.

    Directory of Open Access Journals (Sweden)

    Christel Gumy

    Full Text Available BACKGROUND: Organotins are highly toxic and widely distributed environmental chemicals. Dibutyltin (DBT is used as stabilizer in the production of polyvinyl chloride plastics, and it is also the major metabolite formed from tributyltin (TBT in vivo. DBT is immunotoxic, however, the responsible targets remain to be defined. Due to the importance of glucocorticoids in immune-modulation, we investigated whether DBT could interfere with glucocorticoid receptor (GR function. METHODOLOGY: We used HEK-293 cells transiently transfected with human GR as well as rat H4IIE hepatoma cells and native human macrophages and human THP-1 macrophages expressing endogenous receptor to study organotin effects on GR function. Docking of organotins was used to investigate the binding mechanism. PRINCIPAL FINDINGS: We found that nanomolar concentrations of DBT, but not other organotins tested, inhibit ligand binding to GR and its transcriptional activity. Docking analysis indicated that DBT inhibits GR activation allosterically by inserting into a site close to the steroid-binding pocket, which disrupts a key interaction between the A-ring of the glucocorticoid and the GR. DBT inhibited glucocorticoid-induced expression of phosphoenolpyruvate carboxykinase (PEPCK and tyrosine-aminotransferase (TAT and abolished the glucocorticoid-mediated transrepression of TNF-alpha-induced NF-kappaB activity. Moreover, DBT abrogated the glucocorticoid-mediated suppression of interleukin-6 (IL-6 and TNF-alpha production in lipopolysaccharide (LPS-stimulated native human macrophages and human THP-1 macrophages. CONCLUSIONS: DBT inhibits ligand binding to GR and subsequent activation of the receptor. By blocking GR activation, DBT may disturb metabolic functions and modulation of the immune system, providing an explanation for some of the toxic effects of this organotin.

  7. MELATONIN-INDUCED SUPPRESSION OF PC12 CELL GROWTH IS MEDIATED BY ITS GI COUPLED TRANSMEMBRANE RECEPTORS. (R826248)

    Science.gov (United States)

    The effects of pertussis toxin, an uncoupler of Gi protein from adenylate cyclase, and luzindole, a competitive inhibitor of melatonin receptor binding, were examined for their ability to inhibit melatonin-induced suppression of PC12 cell growth. Both agents inhibited the mela...

  8. SB223412, a neurokinin-3 receptor-selective antagonist, suppresses testosterone secretion in male guinea pigs.

    Science.gov (United States)

    Nakamura, Sho; Ito, Yoshiko; Yamamoto, Koki; Takahashi, Chudai; Dai, Mingdao; Tanahashi, Miyu; Uenoyama, Yoshihisa; Tsukamura, Hiroko; Oishi, Shinya; Maeda, Kei-Ichiro; Matsuda, Fuko

    2017-10-15

    Guinea pigs are important zoo animals and have been recommended for animal-assisted activities or therapy, however there are problems concerning testosterone inducing aggressive or sexual behaviors in male guinea pigs. Testicular testosterone secretion is regulated by pulsatile gonadotropin releasing hormone (GnRH)/luteinizing hormone (LH) release in mammals. The mechanism generating GnRH/LH pulses is thought to be governed by kisspeptin neurons, which coexpress neurokinin B (NKB) and dynorphin A (Dyn), in the arcuate nucleus (ARC). Kisspeptin neurons in the ARC are frequently referred to as KNDy neurons. The purpose of this study was to examine whether the antagonization of NKB-neurokinin-3 receptor (NK3R) signaling can manipulate testosterone secretion in male guinea pigs. A single subcutaneous administration or 7 days of oral administration of an NK3R-selective antagonist, SB223412 (50 mg/body), significantly decreased plasma testosterone levels in male guinea pigs. In vitro binding assays confirmed that SB223412 has a high affinity to guinea pig NK3R. These results suggest that SB223412 could be used as an orally-available compound to suppress testosterone levels in male guinea pigs. Double labeling in situ hybridization of kisspeptin and either NKB or Dyn showed that kisspeptin-expressing neurons contained NKB (77.9%) or Dyn (62.3%) in the ARC, suggesting the presence of KNDy neurons in the ARC of guinea pigs. In conclusion, the present study shows that SB223412 could be a candidate compound to suppress testosterone secretion in male guinea pigs for controlling sexual and aggressive behaviors in the species. Copyright © 2017 Elsevier Inc. All rights reserved.

  9. Improvement of Chicken Primordial Germ Cell Maintenance In Vitro by Blockade of the Aryl Hydrocarbon Receptor Endogenous Activity.

    Science.gov (United States)

    Pérez Sáez, Juan M; Bussmann, Leonardo E; Barañao, J Lino; Bussmann, Ursula A

    2016-06-01

    Primordial germ cells (PGCs) are the undifferentiated progenitors of gametes. Germline competent PGCs can be developed as a cell-based system for genetic modification in chickens, which provides a valuable tool for transgenic technology with both research and industrial applications. This implies manipulation of PGCs, which, in recent years, encouraged a lot of research focused on the study of PGCs and the way of improving their culture. The aryl hydrocarbon receptor (AHR) is a ligand-activated transcription factor that besides mediating toxic responses to environmental contaminants plays pivotal physiological roles in various biological processes. Since a novel compound that acts as an antagonist of this receptor has been reported to promote expansion of hematopoietic stem cells, we conducted the present study with the aim of determining whether addition of an established AHR antagonist to the standard culture medium used nowadays for in vitro chicken PGCs culture improves ex vivo expansion. We have found that addition of α-naphthoflavone in culture medium promotes the amplification of undifferentiated cells and that this effect is exerted by the blockade of AHR action. Our results constitute the first report of the successful use of a readily available AHR antagonist to improve avian PGCs expansion, and they further extend the knowledge of the effects of AHR modulation in undifferentiated cells.

  10. Aryl Hydrocarbon Receptor Antagonists Mitigate the Effects of Dioxin on Critical Cellular Functions in Differentiating Human Osteoblast-Like Cells

    Directory of Open Access Journals (Sweden)

    Chawon Yun

    2018-01-01

    Full Text Available The inhibition of bone healing in humans is a well-established effect associated with cigarette smoking, but the underlying mechanisms are still unclear. Recent work using animal cell lines have implicated the aryl hydrocarbon receptor (AhR as a mediator of the anti-osteogenic effects of cigarette smoke, but the complexity of cigarette smoke mixtures makes understanding the mechanisms of action a major challenge. 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD, dioxin is a high-affinity AhR ligand that is frequently used to investigate biological processes impacted by AhR activation. Since there are dozens of AhR ligands present in cigarette smoke, we utilized dioxin as a prototype ligand to activate the receptor and explore its effects on pro-osteogenic biomarkers and other factors critical to osteogenesis using a human osteoblast-like cell line. We also explored the capacity for AhR antagonists to protect against dioxin action in this context. We found dioxin to inhibit osteogenic differentiation, whereas co-treatment with various AhR antagonists protected against dioxin action. Dioxin also negatively impacted cell adhesion with a corresponding reduction in the expression of integrin and cadherin proteins, which are known to be involved in this process. Similarly, the dioxin-mediated inhibition of cell migration correlated with reduced expression of the chemokine receptor CXCR4 and its ligand, CXCL12, and co-treatment with antagonists restored migratory capacity. Our results suggest that AhR activation may play a role in the bone regenerative response in humans exposed to AhR activators, such as those present in cigarette smoke. Given the similarity of our results using a human cell line to previous work done in murine cells, animal models may yield data relevant to the human setting. In addition, the AhR may represent a potential therapeutic target for orthopedic patients who smoke cigarettes, or those who are exposed to secondhand smoke or other

  11. Cannabidiol induces expression of human cytochrome P450 1A1 that is possibly mediated through aryl hydrocarbon receptor signaling in HepG2 cells.

    Science.gov (United States)

    Yamaori, Satoshi; Kinugasa, Yuka; Jiang, Rongrong; Takeda, Shuso; Yamamoto, Ikuo; Watanabe, Kazuhito

    2015-09-01

    We herein investigated the inducibility of cytochrome P450 1A1 (CYP1A1) by Δ(9)-tetrahydrocannabinol, cannabidiol (CBD), and cannabinol, three major phytocannabinoids, using human hepatoma HepG2 cells. The expression of CYP1A1 and the aryl hydrocarbon receptor (AhR) was measured by a quantitative real-time polymerase chain reaction and/or Western blotting. Δ(9)-Tetrahydrocannabinol and CBD concentration-dependently induced the expression of CYP1A1 mRNA, whereas cannabinol showed little or no induction. Among the phytocannabinoids tested, CBD was the most potent inducer of CYP1A1 expression. The induction of CYP1A1 expression by CBD was significantly attenuated by the knockdown of AhR expression with AhR small interfering RNAs. The role of protein tyrosine kinases (PTKs) in the CBD-mediated induction of CYP1A1 was then examined using herbimycin A, a PTK inhibitor. The upregulation of CYP1A1 by CBD was significantly suppressed by herbimycin A as was the induction by omeprazole but not 3-methylcholanthrene. The inducibility of CYP1A1 by CBD-related compounds was examined to clarify the structural requirements for CBD-mediated CYP1A1 induction. Olivetol, which corresponds to the pentylresorcinol moiety of CBD, significantly induced the expression of CYP1A1, whereas d-limonene, CBD-2'-monomethyl ether, and CBD-2',6'-dimethyl ether did not. These results showed that CBD may have induced human CYP1A1 expression through the activation of PTK-dependent AhR signaling, in which two phenolic hydroxyl groups in the pentylresorcinol moiety of CBD may play structurally important roles. Copyright © 2015. Published by Elsevier Inc.

  12. IgG Suppresses Antibody Responses in Mice Lacking C1q, C3, Complement Receptors 1 and 2, or IgG Fc-Receptors.

    Science.gov (United States)

    Bergström, Joakim J E; Heyman, Birgitta

    2015-01-01

    Antigen-specific IgG antibodies, passively administered to mice or humans together with large particulate antigens like erythrocytes, can completely suppress the antibody response against the antigen. This is used clinically in Rhesus prophylaxis, where administration of IgG anti-RhD prevents RhD-negative women from becoming immunized against RhD-positive fetal erythrocytes aquired transplacentally. The mechanisms by which IgG suppresses antibody responses are poorly understood. We have here addressed whether complement or Fc-receptors for IgG (FcγRs) are required for IgG-mediated suppression. IgG, specific for sheep red blood cells (SRBC), was administered to mice together with SRBC and the antibody responses analyzed. IgG was able to suppress early IgM- as well as longterm IgG-responses in wildtype mice equally well as in mice lacking FcγRIIB (FcγRIIB knockout mice) or FcγRI, III, and IV (FcRγ knockout mice). Moreover, IgG was able to suppress early IgM responses equally well in mice lacking C1q (C1qA knockout mice), C3 (C3 knockout mice), or complement receptors 1 and 2 (Cr2 knockout mice) as in wildtype mice. Owing to the previously described severely impaired IgG responses in the complement deficient mice, it was difficult to assess whether passively administered IgG further decreased their IgG response. In conclusion, Fc-receptor binding or complement-activation by IgG does not seem to be required for its ability to suppress antibody responses to xenogeneic erythrocytes.

  13. Activation of cannabinoid CB1 receptors suppresses the ROS-induced hypersensitivity of rat vagal lung C-fiber afferents.

    Science.gov (United States)

    Yeh, Chou-Ming; Ruan, Ting; Lin, Yu-Jung; Hsu, Tien-Huan

    2016-10-01

    Reactive oxygen species (ROS), including H2O2, have been shown to induce hypersensitivity of vagal lung C-fibers (VLCFs) mainly through receptor potential ankyrin 1 (TRPA1) and P2X receptors. Cannabinoids (CBs) exert antinociceptive effects by binding to specific CB receptors, designated CB1 and CB2 (type 2) for type 1 and type 2, respectively. We investigated whether activation of CB receptors can suppress ROS-mediated VLCF hypersensitivity and, if so, what type(s) of CB receptors are involved. Aerosolized H2O2 (0.05%) was inhaled by anesthetized spontaneously breathing rats (n = 304) to sensitize VLCFs. Airway reflex reactivity to intravenous capsaicin, a VLCF stimulant, was measured. Perivagal pretreatments with various types of agonists and antagonists, a technique that can modulate VLCF sensitivity, were made to delineate the roles of the CB receptors. Aerosolized H2O2 induced an augmented apneic response to capsaicin, which was blocked by bilateral vagotomy or by perivagal capsaicin treatment, suggesting that the response is mediated through VLCFs. Perivagal treatment with HU210 (a nonselective CB agonist) or ACPA (a selective CB1 receptor agonist), but not JWH133 (a CB2 receptor agonist), attenuated this H2O2-induced VLCF hypersensitivity. The suppressive effects of HU210 and ACPA were prevented by an additional treatment with AM251 (a selective CB1 antagonist), but not with AM630 (a selective CB2 antagonist). Perivagal treatment with a combination of ACPA, HC030031 (a TRPA1 receptor antagonist), and iso-PPADS (a P2X receptor antagonist) further attenuated the H2O2-induced VLCF hypersensitivity, as compared with treatment with a combination of HC030031 and iso-PPADS. Our results suggest that activation of CB1 receptors may suppress the ROS-mediated VLCF hypersensitivity through a mechanism that is at least partly distinct from the function of TRPA1 and P2X receptors. Copyright © 2016. Published by Elsevier Ltd.

  14. Engagement of the Mannose Receptor by Tumoral Mucins Activates an Immune Suppressive Phenotype in Human Tumor-Associated Macrophages

    Science.gov (United States)

    Allavena, P.; Chieppa, M.; Bianchi, G.; Solinas, G.; Fabbri, M.; Laskarin, G.; Mantovani, A.

    2010-01-01

    Tumor-Associated Macrophages (TAMs) are abundantly present in the stroma of solid tumors and modulate several important biological processes, such as neoangiogenesis, cancer cell proliferation and invasion, and suppression of adaptive immune responses. Myeloid C-type lectin receptors (CLRs) constitute a large family of transmembrane carbohydrate-binding receptors that recognize pathogens as well as endogenous glycoproteins. Several lines of evidence demonstrate that some CLRs can inhibit the immune response. In this study we investigated TAM-associated molecules potentially involved in their immune suppressive activity. We found that TAMs isolated from human ovarian carcinoma samples predominantly express the CLRs Dectin-1, MDL-1, MGL, DCIR, and most abundantly the Mannose Receptor (MR). Components of carcinomatous ascites and purified tumoral mucins (CA125 and TAG-72) bound the MR and induced its internalization. MR engagement by tumoral mucins and by an agonist anti-MR antibody modulated cytokine production by TAM toward an immune-suppressive profile: increase of IL-10, absence of IL-12, and decrease of the Th1-attracting chemokine CCL3. This study highlights that tumoral mucin-mediated ligation of the MR on infiltrating TAM may contribute to their immune suppressive phenotype. PMID:21331365

  15. RNase L Suppresses Androgen Receptor Signaling, Cell Migration and Matrix Metalloproteinase Activity in Prostate Cancer Cells

    Directory of Open Access Journals (Sweden)

    Shubham Dayal

    2017-03-01

    Full Text Available The interferon antiviral pathways and prostate cancer genetics converge on a regulated endoribonuclease, RNase L. Positional cloning and linkage studies mapped Hereditary Prostate Cancer 1 (HPC1 to RNASEL. To date, there is no correlation of viral infections with prostate cancer, suggesting that RNase L may play additional roles in tumor suppression. Here, we demonstrate a role of RNase L as a suppressor of androgen receptor (AR signaling, cell migration and matrix metalloproteinase activity. Using RNase L mutants, we show that its nucleolytic activity is dispensable for both AR signaling and migration. The most prevalent HPC1-associated mutations in RNase L, R462Q and E265X, enhance AR signaling and cell migration. RNase L negatively regulates cell migration and attachment on various extracellular matrices. We demonstrate that RNase L knockdown cells promote increased cell surface expression of integrin β1 which activates Focal Adhesion Kinase-Sarcoma (FAK-Src pathway and Ras-related C3 botulinum toxin substrate 1-guanosine triphosphatase (Rac1-GTPase activity to increase cell migration. Activity of matrix metalloproteinase (MMP-2 and -9 is significantly increased in cells where RNase L levels are ablated. We show that mutations in RNase L found in HPC patients may promote prostate cancer by increasing expression of AR-responsive genes and cell motility and identify novel roles of RNase L as a prostate cancer susceptibility gene.

  16. RNase L Suppresses Androgen Receptor Signaling, Cell Migration and Matrix Metalloproteinase Activity in Prostate Cancer Cells

    Science.gov (United States)

    Dayal, Shubham; Zhou, Jun; Manivannan, Praveen; Siddiqui, Mohammad Adnan; Ahmad, Omaima Farid; Clark, Matthew; Awadia, Sahezeel; Garcia-Mata, Rafael; Shemshedini, Lirim; Malathi, Krishnamurthy

    2017-01-01

    The interferon antiviral pathways and prostate cancer genetics converge on a regulated endoribonuclease, RNase L. Positional cloning and linkage studies mapped Hereditary Prostate Cancer 1 (HPC1) to RNASEL. To date, there is no correlation of viral infections with prostate cancer, suggesting that RNase L may play additional roles in tumor suppression. Here, we demonstrate a role of RNase L as a suppressor of androgen receptor (AR) signaling, cell migration and matrix metalloproteinase activity. Using RNase L mutants, we show that its nucleolytic activity is dispensable for both AR signaling and migration. The most prevalent HPC1-associated mutations in RNase L, R462Q and E265X, enhance AR signaling and cell migration. RNase L negatively regulates cell migration and attachment on various extracellular matrices. We demonstrate that RNase L knockdown cells promote increased cell surface expression of integrin β1 which activates Focal Adhesion Kinase-Sarcoma (FAK-Src) pathway and Ras-related C3 botulinum toxin substrate 1-guanosine triphosphatase (Rac1-GTPase) activity to increase cell migration. Activity of matrix metalloproteinase (MMP)-2 and -9 is significantly increased in cells where RNase L levels are ablated. We show that mutations in RNase L found in HPC patients may promote prostate cancer by increasing expression of AR-responsive genes and cell motility and identify novel roles of RNase L as a prostate cancer susceptibility gene. PMID:28257035

  17. Allicin inhibits lymphangiogenesis through suppressing activation of vascular endothelial growth factor (VEGF) receptor.

    Science.gov (United States)

    Wang, Weicang; Du, Zheyuan; Nimiya, Yoshiki; Sukamtoh, Elvira; Kim, Daeyoung; Zhang, Guodong

    2016-03-01

    Allicin, the most abundant organosulfur compound in freshly crushed garlic tissues, has been shown to have various health-promoting effects, including anticancer actions. A better understanding of the effects and mechanisms of allicin on tumorigenesis could facilitate development of allicin or garlic products for cancer prevention. Here we found that allicin inhibited lymphangiogenesis, which is a critical cellular process implicated in tumor metastasis. In primary human lymphatic endothelial cells, allicin at 10 μM inhibited capillary-like tube formation and cell migration, and it suppressed phosphorylation of vascular endothelial growth factor receptor 2 and focal adhesion kinase. Using a Matrigel plug assay in mice, addition of 10 μg allicin in Matrigel plug inhibited 40-50% of vascular endothelial growth factor-C-induced infiltration of lymphatic endothelial cells and leukocytes. S-Allylmercaptoglutathione, a major cellular metabolite of allicin, had no effect on lymphangiogenic responses in lymphatic endothelial cells. Together, these results demonstrate the antilymphangiogenic effect of allicin in vitro and in vivo, suggesting a novel mechanism for the health-promoting effects of garlic compounds. Copyright © 2015 Elsevier Inc. All rights reserved.

  18. AP-2{alpha} suppresses skeletal myoblast proliferation and represses fibroblast growth factor receptor 1 promoter activity

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell, Darrion L. [Department of Cell Biology and Anatomy, Chicago Medical School, Rosalind Franklin University of Medicine and Science, 3333 Green Bay Road, North Chicago, IL 60064 (United States); DiMario, Joseph X., E-mail: joseph.dimario@rosalindfranklin.edu [Department of Cell Biology and Anatomy, Chicago Medical School, Rosalind Franklin University of Medicine and Science, 3333 Green Bay Road, North Chicago, IL 60064 (United States)

    2010-01-15

    Skeletal muscle development is partly characterized by myoblast proliferation and subsequent differentiation into postmitotic muscle fibers. Developmental regulation of expression of the fibroblast growth factor receptor 1 (FGFR1) gene is required for normal myoblast proliferation and muscle formation. As a result, FGFR1 promoter activity is controlled by multiple transcriptional regulatory proteins during both proliferation and differentiation of myogenic cells. The transcription factor AP-2{alpha} is present in nuclei of skeletal muscle cells and suppresses myoblast proliferation in vitro. Since FGFR1 gene expression is tightly linked to myoblast proliferation versus differentiation, the FGFR1 promoter was examined for candidate AP-2{alpha} binding sites. Mutagenesis studies indicated that a candidate binding site located at - 1035 bp functioned as a repressor cis-regulatory element. Furthermore, mutation of this site alleviated AP-2{alpha}-mediated repression of FGFR1 promoter activity. Chromatin immunoprecipitation studies demonstrated that AP-2{alpha} interacted with the FGFR1 promoter in both proliferating myoblasts and differentiated myotubes. In total, these results indicate that AP-2{alpha} is a transcriptional repressor of FGFR1 gene expression during skeletal myogenesis.

  19. MicroRNA-133a suppresses multiple oncogenic membrane receptors and cell invasion in non-small cell lung carcinoma.

    Directory of Open Access Journals (Sweden)

    Lu-Kai Wang

    Full Text Available Non-small cell lung cancers (NSCLCs cause high mortality worldwide, and the cancer progression can be activated by several genetic events causing receptor dysregulation, including mutation or amplification. MicroRNAs are a group of small non-coding RNA molecules that function in gene silencing and have emerged as the fine-tuning regulators during cancer progression. MiR-133a is known as a key regulator in skeletal and cardiac myogenesis, and it acts as a tumor suppressor in various cancers. This study demonstrates that miR-133a expression negatively correlates with cell invasiveness in both transformed normal bronchial epithelial cells and lung cancer cell lines. The oncogenic receptors in lung cancer cells, including insulin-like growth factor 1 receptor (IGF-1R, TGF-beta receptor type-1 (TGFBR1, and epidermal growth factor receptor (EGFR, are direct targets of miR-133a. MiR-133a can inhibit cell invasiveness and cell growth through suppressing the expressions of IGF-1R, TGFBR1 and EGFR, which then influences the downstream signaling in lung cancer cell lines. The cell invasive ability is suppressed in IGF-1R- and TGFBR1-repressed cells and this phenomenon is mediated through AKT signaling in highly invasive cell lines. In addition, by using the in vivo animal model, we find that ectopically-expressing miR-133a dramatically suppresses the metastatic ability of lung cancer cells. Accordingly, patients with NSCLCs who have higher expression levels of miR-133a have longer survival rates compared with those who have lower miR-133a expression levels. In summary, we identified the tumor suppressor role of miR-133a in lung cancer outcome prognosis, and we demonstrated that it targets several membrane receptors, which generally produce an activating signaling network during the progression of lung cancer.

  20. Obesity Suppresses Estrogen Receptor Beta Expression in Breast Cancer Cells via a HER2-Mediated Pathway.

    Directory of Open Access Journals (Sweden)

    Laura W Bowers

    Full Text Available Obesity is associated with a worse breast cancer prognosis, while greater breast tumor estrogen receptor beta (ERβ expression is correlated with improved therapy response and survival. The objective of this study was to determine the impact of obesity on breast cancer cell ERβ expression, which is currently unknown. We utilized an in vitro model of obesity in which breast cancer cells were exposed to patient serum pooled by body mass index category (obese (OB: ≥30 kg/m2; normal weight (N: 18.5-24.9 kg/m2. Four human mammary tumor cell lines representing the major breast cancer subtypes (SKBR3, MCF-7, ZR75, MDA-MB-231 and mammary tumor cells from MMTV-neu mice were used. ERβ expression, assessed by qPCR and western blotting, was suppressed in the two HER2-overexpressing cell lines (SKBR3, MMTV-neu following OB versus N sera exposure, but did not vary in the other cell lines. Expression of Bcl-2 and cyclin D1, two genes negatively regulated by ERβ, was elevated in SKBR3 cells following exposure to OB versus N sera, but this difference was eliminated when the ERβ gene was silenced with siRNA. Herceptin, a HER2 antagonist, and siRNA to HER2 were used to evaluate the role of HER2 in sera-induced ERβ modulation. SKBR3 cell treatment with OB sera plus Herceptin increased ERβ expression three-fold. Similar results were obtained when HER2 expression was silenced with siRNA. OB sera also promoted greater SKBR3 cell viability and growth, but this variance was not present when ERβ was silenced or the cells were modified to overexpress ERβ. Based on this data, we conclude that obesity-associated systemic factors suppress ERβ expression in breast cancer cells via a HER2-mediated pathway, leading to greater cell viability and growth. Elucidation of the mechanism(s mediating this effect could provide important insights into how ERβ expression is regulated as well as how obesity promotes a more aggressive disease.

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

    Science.gov (United States)

    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

  2. Gene Interaction Network Suggests Dioxin Induces a Significant Linkage between Aryl Hydrocarbon Receptor and Retinoic Acid Receptor Beta

    Science.gov (United States)

    Toyoshiba, Hiroyoshi; Yamanaka, Takeharu; Sone, Hideko; Parham, Frederick M.; Walker, Nigel J.; Martinez, Jeanelle; Portier, Christopher J.

    2004-01-01

    Gene expression arrays (gene chips) have enabled researchers to roughly quantify the level of mRNA expression for a large number of genes in a single sample. Several methods have been developed for the analysis of gene array data including clustering, outlier detection, and correlation studies. Most of these analyses are aimed at a qualitative identification of what is different between two samples and/or the relationship between two genes. We propose a quantitative, statistically sound methodology for the analysis of gene regulatory networks using gene expression data sets. The method is based on Bayesian networks for direct quantification of gene expression networks. Using the gene expression changes in HPL1A lung airway epithelial cells after exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin at levels of 0.1, 1.0, and 10.0 nM for 24 hr, a gene expression network was hypothesized and analyzed. The method clearly demonstrates support for the assumed network and the hypothesis linking the usual dioxin expression changes to the retinoic acid receptor system. Simulation studies demonstrated the method works well, even for small samples. PMID:15345368

  3. Probing the Effector and Suppressive Functions of Human T Cell Subsets Using Antigen-Specific Engineered T Cell Receptors

    OpenAIRE

    Qi Wan; Lina Kozhaya; Keren Imberg; Frances Mercer; Shi Zhong; Michelle Krogsgaard; Derya Unutmaz

    2013-01-01

    Activation of T cells through the engagement of the T cell receptors (TCRs) with specific peptide-MHC complexes on antigen presenting cells (APCs) is the major determinant for their proliferation, differentiation and display of effector functions. To assess the role of quantity and quality of peptide-MHC presentation in eliciting T cell activation and suppression functions, we genetically engineered human T cells with two TCRs that recognize HLA-A*0201-restricted peptides derived from either ...

  4. Receptor modelling study of polycyclic aromatic hydrocarbons in Jeddah, Saudi Arabia

    Energy Technology Data Exchange (ETDEWEB)

    Alghamdi, Mansour A. [Department of Environmental Sciences, Faculty of Meteorology, Environment and Arid Land Agriculture, King Abdulaziz University, Jeddah (Saudi Arabia); Alam, Mohammed S., E-mail: m.s.alam@bham.ac.uk [Division of Environmental Health and Risk Management, School of Geography, Earth and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom); Yin, Jianxin; Stark, Christopher; Jang, Eunhwa [Division of Environmental Health and Risk Management, School of Geography, Earth and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom); Harrison, Roy M., E-mail: r.m.harrison@bham.ac.uk [Department of Environmental Sciences, Faculty of Meteorology, Environment and Arid Land Agriculture, King Abdulaziz University, Jeddah (Saudi Arabia); Division of Environmental Health and Risk Management, School of Geography, Earth and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom); Shamy, Magdy; Khoder, Mamdouh I.; Shabbaj, Ibrahim I. [Department of Environmental Sciences, Faculty of Meteorology, Environment and Arid Land Agriculture, King Abdulaziz University, Jeddah (Saudi Arabia)

    2015-02-15

    Measurements of 14 polycyclic aromatic hydrocarbons (PAH) have been made in Jeddah, Saudi Arabia, with a view to establishing the concentrations in this major city, and quantifying the contributions of major sources. Particulate and vapour forms have been sampled and analysed separately. The concentrations are compared to measurements from other sites in the Middle Eastern region and are towards the lower end of the range, being far lower than concentrations reported from Riyadh (Saudi Arabia), Assiut (Egypt) and Tehran (Iran) but broadly similar to those measured in Damascus (Syria) and higher than those measured in Kuwait. The partitioning between vapour and particle phases is similar to that in data from Egypt and China, but with many compounds showing a higher particle-associated percentage than in Birmingham (UK) possibly reflecting a higher concentration of airborne particulate matter in the former countries. Concentrations in Jeddah were significantly higher at a site close to the oil refinery and a site close to a major ring road than at a suburban site to the north of the city. Application of positive matrix factorisation to the pooled data elicited three factors accounting respectively for 17%, 33% and 50% of the measured sum of PAH and these are interpreted as arising from gasoline vehicles, industrial sources, particularly the oil refinery, and to diesel/fuel oil combustion. - Highlights: • Measurements of 14 PAH compounds in vapour and particulate phases at three sites. • Comparison of concentrations across Jeddah and Middle Eastern regions. • Application of positive matrix factorisation to identify possible sources.

  5. Omeprazole Attenuates Pulmonary Aryl Hydrocarbon Receptor Activation and Potentiates Hyperoxia-Induced Developmental Lung Injury in Newborn Mice.

    Science.gov (United States)

    Shivanna, Binoy; Zhang, Shaojie; Patel, Ananddeep; Jiang, Weiwu; Wang, Lihua; Welty, Stephen E; Moorthy, Bhagavatula

    2015-11-01

    Hyperoxia contributes to the development of bronchopulmonary dysplasia (BPD) in human preterm infants and a similar lung phenotype characterized by alveolar simplification in newborn mice. Omeprazole (OM) is a proton pump inhibitor that is used to treat humans with gastric acid related disorders. OM-mediated aryl hydrocarbon receptor (AhR) activation attenuates acute hyperoxic lung injury (HLI) in adult mice. Whether OM activates pulmonary AhR and protects C57BL/6J newborn mice against hyperoxia-induced developmental lung (alveolar and pulmonary vascular simplification, inflammation, and oxidative stress) injury (HDLI) is unknown. Therefore, we tested the hypothesis that OM will activate pulmonary AhR and mitigate HDLI in newborn mice. Newborn mice were treated daily with i.p. injections of OM at doses of 10 (OM10) or 25 (OM25) mg/kg while being exposed to air or hyperoxia (FiO2 of 85%) for 14 days, following which their lungs were harvested to determine alveolarization, pulmonary vascularization, inflammation, oxidative stress, vascular injury, and AhR activation. To our surprise, hyperoxia-induced alveolar and pulmonary vascular simplification, inflammation, oxidative stress, and vascular injury were augmented in OM25-treated animals. These findings were associated with attenuated pulmonary vascular endothelial growth factor receptor 2 expression and decreased pulmonary AhR activation in the OM25 group. We conclude that contrary to our hypothesis, OM decreases functional activation of pulmonary AhR and potentiates HDLI in newborn mice. These observations are consistent with our previous findings, which suggest that AhR activation plays a protective role in HDLI in newborn mice. © The Author 2015. Published by Oxford University Press on behalf of the Society of Toxicology. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  6. Altered subcellular localization of heat shock protein 90 is associated with impaired expression of the aryl hydrocarbon receptor pathway in dogs.

    Directory of Open Access Journals (Sweden)

    Frank G van Steenbeek

    Full Text Available The aryl hydrocarbon receptor (AHR mediates biological responses to toxic chemicals. An unexpected role for AHR in vascularization was suggested when mice lacking AHR displayed impaired closure of the ductus venosus after birth, as did knockout mice for aryl hydrocarbon receptor interacting protein (AIP and aryl hydrocarbon receptor nuclear translocator (ARNT. The resulting intrahepatic portosystemic shunts (IHPSS are frequently diagnosed in specific dog breeds, such as the Irish wolfhound. We compared the expression of components of the AHR pathway in healthy Irish wolfhounds and dogs with IHPSS. To this end, we analyzed the mRNA expression in the liver of AHR,AIP, ARNT, and other genes involved in this pathway, namely, those for aryl hydrocarbon receptor nuclear translocator 2 (ARNT2, hypoxia inducible factor 1alpha (HIF1A, heat shock protein 90AA1 (HSP90AA1, cytochromes P450 (CYP1A1, CYP1A2, and CYP1B1, vascular endothelial growth factor A (VEGFA, nitric oxide synthesase 3 (NOS3, and endothelin (EDN1. The observed low expression of AHR mRNA in the Irish wolfhounds is in associated with a LINE-1 insertion in intron 2, for which these dogs were homozygous. Down regulation in Irish wolfhounds was observed for AIP, ARNT2, CYP1A2, CYP1B1 and HSP90AA1 expression, whereas the expression of HIF1A was increased. Immunohistochemistry revealed lower levels of AHR, HIF1A, and VEGFA protein in the nucleus and lower levels of ARNT and HSP90AA1 protein in the cytoplasm of the liver cells of Irish wolfhounds. The impaired expression of HSP90AA1 could trigger the observed differences in mRNA and protein levels and therefore explain the link between two very different functions of AHR: regulation of the closure of the ductus venosus and the response to toxins.

  7. Circadian clock gene aryl hydrocarbon receptor nuclear translocator-like polymorphisms are associated with seasonal affective disorder: An Indian family study

    OpenAIRE

    Rajendran, Bhagya; Janakarajan, Veeramahali Natarajan

    2016-01-01

    Background and Aim: Polymorphisms in aryl hydrocarbon receptor nuclear translocator-like (ARNTL) gene, the key component of circadian clock manifests circadian rhythm abnormalities. As seasonal affective disorder (SAD) is associated with disrupted circadian rhythms, the main objective of this study was to screen an Indian family with SAD for ARNTL gene polymorphisms. Materials and Methods: In this study, 30 members of close-knit family with SAD, 30 age- and sex-matched controls of the same ca...

  8. Lack of Ligand-Selective Binding of the Aryl Hydrocarbon Receptor to Putative DNA Binding Sites Regulating Expression of Bax and Paraoxonase 1 Genes

    OpenAIRE

    DeGroot, Danica E.; Hayashi, Ai; Michael S Denison

    2013-01-01

    The aryl hydrocarbon receptor (AhR) is a ligand-dependent transcription factor that mediates the biological and toxicological effects of structurally diverse chemicals through its ability to bind specific DNA recognition sites (dioxin responsive elements (DREs)), and activate transcription of adjacent genes. While the DRE has a highly conserved consensus sequence, it has been suggested that the nucleotide specificity of AhR DNA binding may be ligand-dependent. The upstream regulatory regions ...

  9. The dietary constituent resveratrol suppresses nociceptive neurotransmission via the NMDA receptor.

    Science.gov (United States)

    Takehana, Shiori; Kubota, Yoshiko; Uotsu, Nobuo; Yui, Kei; Iwata, Koichi; Shimazu, Yoshihito; Takeda, Mamoru

    2017-01-01

    Background Although we have previously reported that intravenous resveratrol administration inhibits the nociceptive neuronal activity of spinal trigeminal nucleus caudalis neurons, the site of the central effect remains unclear. The aim of the present study was to examine whether acute intravenous resveratrol administration in the rat attenuates central glutamatergic transmission of spinal trigeminal nucleus caudalis neurons responding to nociceptive mechanical stimulation in vivo, using extracellular single-unit recordings and microiontophoretic techniques. Results Extracellular single-unit recordings using multibarrel electrodes were made from the spinal trigeminal nucleus caudalis wide dynamic range neurons responding to orofacial mechanical stimulation in pentobarbital anesthetized rats. These neurons also responded to iontophoretic application of glutamate, and the evoked neuronal discharge frequency was significantly increased in a current-dependent and reversible manner. The mean firing frequency evoked by the iontophoretic application of glutamate (30, 50, and 70 nA) was mimicked by the application of 10 g, 60 g, and noxious pinch mechanical stimulation, respectively. The mean firing frequency of spinal trigeminal nucleus caudalis wide dynamic range neurons responding to iontophoretic application of glutamate and N-methyl-D-aspartate were also significantly inhibited by intravenous administration of resveratrol (2 mg/kg) and the maximal inhibition of discharge frequency was observed within 10 min. These inhibitory effects lasted approximately 20 min. The relative magnitude of inhibition by resveratrol of the glutamate-evoked spinal trigeminal nucleus caudalis wide dynamic range neuronal discharge frequency was similar to that for N-methyl-D-aspartate iontophoretic application. Conclusion These results suggest that resveratrol suppresses glutamatergic neurotransmission of the spinal trigeminal nucleus caudalis neurons responding to nociceptive

  10. Troglitazone suppresses telomerase activity independently of PPARγ in estrogen-receptor negative breast cancer cells

    Directory of Open Access Journals (Sweden)

    Nguyen Johnny

    2010-07-01

    Full Text Available Abstract Background Breast cancer is one the highest causes of female cancer death worldwide. Many standard chemotherapeutic agents currently used to treat breast cancer are relatively non-specific and act on all rapidly dividing cells. In recent years, more specific targeted therapies have been introduced. It is known that telomerase is active in over 90% of breast cancer tumors but inactive in adjacent normal tissues. The prevalence of active telomerase in breast cancer patients makes telomerase an attractive therapeutic target. Recent evidence suggests that telomerase activity can be suppressed by peroxisome proliferator activated receptor gamma (PPARγ. However, its effect on telomerase regulation in breast cancer has not been investigated. Methods In this study, we investigated the effect of the PPARγ ligand, troglitazone, on telomerase activity in the MDA-MB-231 breast cancer cell line. Real time RT-PCR and telomerase activity assays were used to evaluate the effect of troglitazone. MDA-MB-231 cells had PPARγ expression silenced using shRNA interference. Results We demonstrated that troglitazone reduced the mRNA expression of hTERT and telomerase activity in the MDA-MB-231 breast cancer cell line. Troglitazone reduced telomerase activity even in the absence of PPARγ. In agreement with this result, we found no correlation between PPARγ and hTERT mRNA transcript levels in breast cancer patients. Statistical significance was determined using Pearson correlation and the paired Student's t test. Conclusions To our knowledge, this is the first time that the effect of troglitazone on telomerase activity in breast cancer cells has been investigated. Our data suggest that troglitazone may be used as an anti-telomerase agent; however, the mechanism underlying this inhibitory effect remains to be determined.

  11. Testosterone suppresses oxidative stress via androgen receptor-independent pathway in murine cardiomyocytes.

    Science.gov (United States)

    Zhang, Li; Wu, Saizhu; Ruan, Yunjun; Hong, Lei; Xing, Xiaowen; Lai, Wenyan

    2011-01-01

    Evidence supports that oxidative stress exerts significant effects on the pathogenesis of heart dysfunction. On the other hand, the presence of specific androgen receptor (AR) in mammalian cardiomyocytes implies that androgen plays a physiological role in cardiac function, myocardial injury and the regulation of the redox state in the heart. This study used the testicular feminized (Tfm) and castrated male mice to investigate the effects of testosterone deficiency, physiological testosterone therapy and AR on oxidative stress in cardiomyocytes. Tfm mice have a non-functional AR and reduced circulating testosterone levels. Male littermates and Tfm mice were separated into 5 experimental groups: non-castrated littermate controls, castrated littermates, sham-operated Tfm, testosterone-treated castrated littermates and testosterone-treated sham-operated Tfm mice. Cardiomyocytes that were isolated from the left ventricle were used for determination of superoxide dismutase (SOD), glutathione peroxidase (GSH‑Px) enzyme activities, and malondialdehyde (MDA) levels. Additionally, mitochondrial DNA (mtDNA) deletion mutations were detected by nested PCR. The SOD and GSH-Px enzyme activities of cardiomyocytes were decreased, and the MDA levels and the proportion of mtDNA mutations were increased in castrated and sham-operated Tfm mice compared to control mice. However, an increase was observed in the activities of SOD and GSH-Px enzyme as well as a decrease in MDA levels and the proportion of mtDNA mutations in the mice that had received testosterone therapy. These changes were statistically similar in castrated and sham-operated Tfm mice after testosterone therapy. In conclusion, it is testosterone deficiency that induces oxidative stress in cardiomyocytes. Physiological testosterone therapy is able to suppress oxidative stress mediated via the AR-independent pathway.

  12. Induction of bacterial lipoprotein tolerance is associated with suppression of toll-like receptor 2 expression.

    LENUS (Irish Health Repository)

    Wang, Jiang Huai

    2012-02-03

    Tolerance to bacterial cell wall components including lipopolysaccharide (LPS) may represent an essential regulatory mechanism during bacterial infection. Two members of the Toll-like receptor (TLR) family, TLR2 and TLR4, recognize the specific pattern of bacterial cell wall components. TLR4 has been found to be responsible for LPS tolerance. However, the role of TLR2 in bacterial lipoprotein (BLP) tolerance and LPS tolerance is unclear. Pretreatment of human THP-1 monocytic cells with a synthetic bacterial lipopeptide induced tolerance to a second BLP challenge with diminished tumor necrosis factor-alpha and interleukin-6 production, termed BLP tolerance. Furthermore, BLP-tolerized THP-1 cells no longer responded to LPS stimulation, indicating a cross-tolerance to LPS. Induction of BLP tolerance was CD14-independent, as THP-1 cells that lack membrane-bound CD14 developed tolerance both in serum-free conditions and in the presence of a specific CD14 blocking monoclonal antibody (MEM-18). Pre-exposure of THP-1 cells to BLP suppressed mitogen-activated protein kinase phosphorylation and nuclear factor-kappaB activation in response to subsequent BLP and LPS stimulation, which is comparable with that found in LPS-tolerized cells, indicating that BLP tolerance and LPS tolerance may share similar intracellular pathways. However, BLP strongly enhanced TLR2 expression in non-tolerized THP-1 cells, whereas LPS stimulation had no effect. Furthermore, a specific TLR2 blocking monoclonal antibody (2392) attenuated BLP-induced, but not LPS-induced, tumor necrosis factor-alpha and interleukin-6 production, indicating BLP rather than LPS as a ligand for TLR2 engagement and activation. More importantly, pretreatment of THP-1 cells with BLP strongly inhibited TLR2 activation in response to subsequent BLP stimulation. In contrast, LPS tolerance did not prevent BLP-induced TLR2 overexpression. These results demonstrate that BLP tolerance develops through down-regulation of TLR2

  13. Cell and region specificity of Aryl hydrocarbon Receptor (AhR) system in the testis and the epididymis.

    Science.gov (United States)

    Wajda, A; Łapczuk, J; Grabowska, M; Pius-Sadowska, E; Słojewski, M; Laszczynska, M; Urasinska, E; Machalinski, B; Drozdzik, M

    2017-04-01

    Aryl hydrocarbon receptor (AhR) plays multiple important functions in adaptive responses. Exposure to AhR ligands may produce an altered metabolic activity controlled by the AhR pathways, and consequently affect drug/toxin responses, hormonal status and cellular homeostasis. This research revealed species-, cell- and region-specific pattern of the AhR system expression in the rat and human testis and epididymis, complementing the existing knowledge, especially within the epididymal segments. The study showed that AhR level in the rat and human epididymis is higher than in the testis. The downregulation of AhR expression after TCDD treatment was revealed in the spermatogenic cells at different stages and the epididymal epithelial cells, but not in the Sertoli and Leydig cells. Hence, this basic research provides information about the AhR function in the testis and epididymis, which may provide an insight into deleterious effects of drugs, hormones and environmental pollutants on male fertility. Copyright © 2017 Elsevier Inc. All rights reserved.

  14. Activation of the Aryl Hydrocarbon Receptor during Different Critical Windows in Pregnancy Alters Mammary Epithelial Cell Proliferation and Differentiation

    Science.gov (United States)

    Lew, Betina J.; Collins, Loretta L.; O'Reilly, Michael A.; Lawrence, B. Paige

    2009-01-01

    Exposure to the aryl hydrocarbon receptor (AhR) agonist 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) during pregnancy causes severe defects in mammary gland development and function; however, the underlying mechanism remains unclear. Alterations in epithelial cell proliferation, differentiation, and apoptosis during pregnancy-related mammary development can lead to failed lactogenesis. To determine which of these processes are affected and at what time periods, we examined proliferation, differentiation and apoptosis in mammary glands following exposure to TCDD during early, mid or throughout pregnancy. Although AhR activation throughout pregnancy did not cause early involution, there was a 50% decrease in cell proliferation, which was observed as early as the sixth day of pregnancy (DP). TCDD treatment on the day of impregnation only reduced development and proliferation in early and mid-pregnancy, followed by partial recovery by DP17. However, when AhR activation was delayed to DP7, developmental impairment was not observed in mid-pregnancy, but became evident by DP17, whereas proliferation was reduced at all times. Thus, early exposure to TCDD was neither necessary nor sufficient to cause persistent defects in lactogenesis. These varying outcomes in mammary development due to exposure at different times in pregnancy suggest there are critical windows during which AhR activation impairs mammary epithelial cell proliferation and differentiation. PMID:19502548

  15. Aryl Hydrocarbon Receptor Activation by TCDD Modulates Expression of Extracellular Matrix Remodeling Genes during Experimental Liver Fibrosis

    Directory of Open Access Journals (Sweden)

    Cheri L. Lamb

    2016-01-01

    Full Text Available The aryl hydrocarbon receptor (AhR is a soluble, ligand-activated transcription factor that mediates the toxicity of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD. Increasing evidence implicates the AhR in regulating extracellular matrix (ECM homeostasis. We recently reported that TCDD increased necroinflammation and myofibroblast activation during liver injury elicited by carbon tetrachloride (CCl4. However, TCDD did not increase collagen deposition or exacerbate fibrosis in CCl4-treated mice, which raises the possibility that TCDD may enhance ECM turnover. The goal of this study was to determine how TCDD impacts ECM remodeling gene expression in the liver. Male C57BL/6 mice were treated for 8 weeks with 0.5 mL/kg CCl4, and TCDD (20 μg/kg was administered during the last two weeks. Results indicate that TCDD increased mRNA levels of procollagen types I, III, IV, and VI and the collagen processing molecules HSP47 and lysyl oxidase. TCDD also increased gelatinase activity and mRNA levels of matrix metalloproteinase- (MMP- 3, MMP-8, MMP-9, and MMP-13. Furthermore, TCDD modulated expression of genes in the plasminogen activator/plasmin system, which regulates MMP activation, and it also increased TIMP1 gene expression. These findings support the notion that AhR activation by TCDD dysregulates ECM remodeling gene expression and may facilitate ECM metabolism despite increased liver injury.

  16. Essential oils of culinary herbs and spices display agonist and antagonist activities at human aryl hydrocarbon receptor AhR.

    Science.gov (United States)

    Bartoňková, Iveta; Dvořák, Zdeněk

    2018-01-01

    Essential oils (EOs) of culinary herbs and spices are used to flavor, color and preserve foods and drinks. Dietary intake of EOs is significant, deserving an attention of toxicologists. We examined the effects of 31 EOs of culinary herbs and spices on the transcriptional activity of human aryl hydrocarbon receptor (AhR), which is a pivotal xenobiotic sensor, having also multiple roles in human physiology. Tested EOs were sorted out into AhR-inactive ones (14 EOs) and AhR-active ones, including full agonists (cumin, jasmine, vanilla, bay leaf), partial agonists (cloves, dill, thyme, nutmeg, oregano) and antagonists (tarragon, caraway, turmeric, lovage, fennel, spearmint, star anise, anise). Major constituents (>10%) of AhR-active EOs were studied in more detail. We identified AhR partial agonists (carvacrol, ligustilide, eugenol, eugenyl acetate, thymol, ar-turmerone) and antagonists (trans-anethole, butylidine phtalide, R/S-carvones, p-cymene), which account for AhR-mediated activities of EOs of fennel, anise, star anise, caraway, spearmint, tarragon, cloves, dill, turmeric, lovage, thyme and oregano. We also show that AhR-mediated effects of some individual constituents of EOs differ from those manifested in mixtures. In conclusion, EOs of culinary herbs and spices are agonists and antagonists of human AhR, implying a potential for food-drug interactions and interference with endocrine pathways. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Water exposure assessment of aryl hydrocarbon receptor agonists in Three Gorges Reservoir, China using SPMD-based virtual organisms.

    Science.gov (United States)

    Wang, Jingxian; Bernhöft, Silke; Pfister, Gerd; Schramm, Karl-Werner

    2014-10-15

    SPMD-based virtual organisms (VOs) were deployed at five to eight sites in the Three Gorges Reservoir (TGR), China for five periods in 2008, 2009 and 2011. The water exposure of aryl hydrocarbon receptor (AhR) agonists was assessed by the VOs. The chosen bioassay response for the extracts of the VOs, the induction of 7-ethoxyresorufin-O-deethylase (EROD) was assayed using a rat hepatoma cell line (H4IIE). The results show that the extracts from the VOs could induce AhR activity significantly, whereas the chemically derived 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) equivalent (TEQcal) accounted for dam were also obviously higher in 2009 and 2011 than in 2008, indicating big changes in the composition of pollutants in the area after water level reached a maximum of 175 m. Although the aqueous concentration of AhR agonists of 0.8-4.8 pg TCDDL(-1) in TGR was not alarming, the tendency of accumulating high concentration of AhR agonists in VO lipid and existence of possible synergism or antagonism in the water may exhibit a potential hazard to local biota being exposed to AhR agonists. Copyright © 2014 Elsevier B.V. All rights reserved.

  18. Prenatal polycyclic aromatic hydrocarbon, adiposity, peroxisome proliferator-activated receptor (PPAR γ methylation in offspring, grand-offspring mice.

    Directory of Open Access Journals (Sweden)

    Zhonghai Yan

    Full Text Available Greater levels of prenatal exposure to polycyclic aromatic hydrocarbon (PAH have been associated with childhood obesity in epidemiological studies. However, the underlying mechanisms are unclear.We hypothesized that prenatal PAH over-exposure during gestation would lead to weight gain and increased fat mass in offspring and grand-offspring mice. Further, we hypothesized that altered adipose gene expression and DNA methylation in genes important to adipocyte differentiation would be affected.Pregnant dams were exposed to a nebulized PAH mixture versus negative control aerosol 5 days a week, for 3 weeks. Body weight was recorded from postnatal day (PND 21 through PND60. Body composition, adipose cell size, gene expression of peroxisome proliferator-activated receptor (PPAR γ, CCAAT/enhancer-binding proteins (C/EBP α, cyclooxygenase (Cox-2, fatty acid synthase (FAS and adiponectin, and DNA methylation of PPAR γ, were assayed in both the offspring and grand-offspring adipose tissue.Offspring of dams exposed to greater PAH during gestation had increased weight, fat mass, as well as higher gene expression of PPAR γ, C/EBP α, Cox2, FAS and adiponectin and lower DNA methylation of PPAR γ. Similar differences in phenotype and DNA methylation extended through the grand-offspring mice.Greater prenatal PAH exposure was associated with increased weight, fat mass, adipose gene expression and epigenetic changes in progeny.

  19. Elevated Exposures to Polycyclic Aromatic Hydrocarbons and Other Organic Mutagens in Ottawa Firefighters Participating in Emergency, On-Shift Fire Suppression.

    Science.gov (United States)

    Keir, Jennifer L A; Akhtar, Umme S; Matschke, David M J; Kirkham, Tracy L; Chan, Hing Man; Ayotte, Pierre; White, Paul A; Blais, Jules M

    2017-11-07

    Occupational exposures to combustion emissions were examined in Ottawa Fire Service (OFS) firefighters. Paired urine and dermal wipe samples (i.e., pre- and post-event) as well as personal air samples and fire event questionnaires were collected from 27 male OFS firefighters. A total of 18 OFS office workers were used as additional controls. Exposures to polycyclic aromatic hydrocarbons (PAHs) and other organic mutagens were assessed by quantification of urinary PAH metabolite levels, levels of PAHs in dermal wipes and personal air samples, and urinary mutagenicity using the Salmonella mutagenicity assay (Ames test). Urinary Clara Cell 16 (CC16) and 15-isoprostane F2t (8-iso-PGF2α) levels were used to assess lung injury and overall oxidative stress, respectively. The results showed significant 2.9- to 5.3-fold increases in average post-event levels of urinary PAH metabolites, depending on the PAH metabolite (p emergency, on-shift fire suppression is associated with significantly elevated exposures to combustion emissions.

  20. Employing CO2as reaction medium for in-situ suppression of the formation of benzene derivatives and polycyclic aromatic hydrocarbons during pyrolysis of simulated municipal solid waste.

    Science.gov (United States)

    Lee, Jechan; Choi, Dongho; Tsang, Yiu Fai; Oh, Jeong-Ik; Kwon, Eilhann E

    2017-05-01

    This study proposes a strategic principle to enhance the thermal efficiency of pyrolysis of municipal solid waste (MSW). An environmentally sound energy recovery platform was established by suppressing the formation of harmful organic compounds evolved from pyrolysis of MSW. Using CO 2 as reaction medium/feedstock, CO generation was enhanced through the following: 1) expediting the thermal cracking of volatile organic carbons (VOCs) evolved from the thermal degradation of the MSWs and 2) directly reacting VOCs with CO 2 . This particular influence of CO 2 on pyrolysis of the MSWs also led to the in-situ mitigation of harmful organic compounds (e.g., benzene derivatives and polycyclic aromatic hydrocarbons (PAHs)) considering that CO 2 acted as a carbon scavenger to block reaction pathways toward benzenes and PAHs in pyrolysis. To understand the fundamental influence of CO 2 , simulated MSWs (i.e., various ratios of biomass to polymer) were used to avoid any complexities arising from the heterogeneous matrix of MSW. All experimental findings in this study suggested the foreseeable environmental application of CO 2 to energy recovery from MSW together with disposal of MSW. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Ramelteon, a selective MT1/MT2 receptor agonist, suppresses the proliferation and invasiveness of endometrial cancer cells.

    Science.gov (United States)

    Osanai, Kiyono; Kobayashi, Yoichi; Otsu, Masahiro; Izawa, Tomoko; Sakai, Keiji; Iwashita, Mitsutoshi

    2017-07-01

    The incidence of endometrial cancer is increasing, making it the fifth most common cancer worldwide. To date, however, there is no standard therapy for patients with recurrent endometrial cancer. Melatonin, a hormone secreted by the pineal gland, has been shown to have anti-tumor effects in various tumor types. Although melatonin is available as a supplement, it has not been approved for cancer treatment. Ramelteon, a selective melatonin receptor type 1 and 2 (MT1/MT2) receptor agonist, has been approved to treat sleep disorders, suggesting that ramelteon may be effective in the treatment of endometrial cancer. To determine whether this agent may be effective in the treatment of endometrial cancer, this study investigated the ability of ramelteon to suppress the proliferation and invasiveness of HHUA cells, an estrogen receptor-positive endometrial cancer cell line. Ramelteon at 10 -8 M maximally suppressed the proliferation of HHUA cells, reducing the percentage of Ki-67 positive proliferating cells. This effect was completely blocked by luzindole, a MT1/MT2 receptor antagonist. Furthermore, ramelteon inhibited HHUA cell invasion and reduced the expression of the MMP-2 and MMP-9 genes. These results suggested that ramelteon may be a candidate for the treatment of recurrent endometrial cancer, with activity similar to that of melatonin.

  2. Hyperglycemia attenuates receptor activator of NF-κB ligand-induced macrophage activation by suppressing insulin signaling.

    Science.gov (United States)

    Kurihara, Chitaru; Tanaka, Teruyoshi; Yamanouchi, Dai

    2017-06-15

    Although male gender, aging, hypertension, dyslipidemia, and smoking are common risk factors for abdominal aortic aneurysm, diabetes mellitus is an independent negative risk factor. In aneurysm tissue, matrix metalloproteinases (MMPs) expressed by activated macrophages degrades extracellular matrix proteins. In our previous experimental study, we demonstrated that the aneurysmal formation and macrophage activity were suppressed by inhibiting mimicking hyperglycemia (HG) through upregulation of glucose-sensing nuclear receptor, Nr1h2. Here in this study, we focused on the role of HG-induced altered glucose uptake on macrophage activation. RAW264.7 murine macrophage cells were pretreated in cultures containing HG (HG group, 15.5 mM) or normal glucose (NG) concentrations (NG group, 5.5 mM) for 7 d. The culture medium was then changed in both groups to NG conditions, and the cells were stimulated with recombinant murine soluble receptor activator of NF-κB ligand (sRANKL). Macrophage activation was confirmed by tartrate-resistant acid phosphatase (TRAP) staining. Compared with the NG group, MMP-9 expression in the HG group was significantly suppressed. Glucose uptake was increased in the NG group but not in the HG group during macrophage activation. To determine the mechanism of activation, we studied the expression and distribution of glucose transporters (Gluts) in the macrophages. Although Glut expression was unaffected by glucose pretreatment, membrane translocation of Glut-1 was significantly enhanced in macrophages in the NG group but not in the HG group during activation. Insulin receptor and insulin receptor substrate-1 (IRS-1) messenger RNA, known stimulate to membrane translocation of Gluts, were both decreased by the HG condition but not by the NG condition. HG pretreatment suppressed the macrophage activation. sRANKL increased macrophage glucose uptake at NG concentrations, which was impaired by HG pretreatment through the inhibition of Glut1 membrane

  3. The muscarinic receptor antagonist tropicamide suppresses tremulous jaw movements in a rodent model of parkinsonian tremor: possible role of M4 receptors.

    Science.gov (United States)

    Betz, Adrienne J; McLaughlin, Peter J; Burgos, Melissa; Weber, Suzanne M; Salamone, John D

    2007-10-01

    Nonselective muscarinic acetylcholine antagonists have been used for several years as antiparkinsonian drugs. However, there are at least five subtypes of muscarinic receptor (M1-5). Neostriatal M4 receptors have been implicated in aspects of motor function, and it has been suggested that M4 antagonists could be used as treatments for parkinsonism. Currently, there is a lack of highly selective M4 antagonists that readily penetrate the blood brain barrier. Thus, the present studies focused upon the effects of tropicamide, a muscarinic acetylcholine receptor antagonist with moderate binding selectivity for the M4 receptor subtype. Tremulous jaw movements were used as a model of parkinsonian tremor in these studies, and the effects of tropicamide were compared with those of the nonselective muscarinic antagonist atropine. Tropicamide suppressed the tremulous jaw movements induced by the muscarinic agonist pilocarpine and the dopamine antagonist pimozide. Analysis of the dose-response curves indicated that tropicamide showed approximately the same potency as atropine for suppression of pilocarpine-induced jaw movements but was more potent than atropine on the suppression of pimozide-induced jaw movements. In contrast, atropine was more potent than tropicamide in terms of impairing performance on visual stimulus detection and delayed nonmatch-to-position tasks. These studies demonstrate that tropicamide, which currently is used clinically for ophthalmic purposes, can exert actions that are consistent with antiparkinsonian effects. Moreover, the different pattern of effects shown by tropicamide compared to those of atropine on motor vs cognitive tasks could be due to the modest M4 selectivity shown by tropicamide.

  4. alpha2-Adrenoceptor antagonists reverse the 5-HT2 receptor antagonist suppression of head-twitch behavior in mice.

    Science.gov (United States)

    Matsumoto, K; Mizowaki, M; Thongpraditchote, S; Murakami, Y; Watanabe, H

    1997-03-01

    The alpha2-adrenoceptor agonist clonidine, as well as 5-HT2 receptor antagonists, reportedly suppress 5-HT2 receptor-mediated head-twitch behavior. We investigated the effect of alpha2-adrenoceptor antagonists on the suppressive action of 5-HT2 receptor antagonists in mice pretreated with the noradrenaline toxin 6-hydroxydopamine (6-OHDA) or the 5-HT synthesis inhibitor p-chlorophenylalanine (p-CPA). In normal mice, idazoxan (0.08-0.2 mg/kg, IP) or yohimbine (0.2-2.0 mg/kg, IP), both alpha2-adrenoceptor antagonists, had no effect on the head-twitch response caused by 5-methoxy-N,N-dimethyltryptamine (5-MeO-DMT; 16 mg/kg, IP), but idazoxan significantly enhanced the response at 0.5 mg/kg. On the other hand, these alpha2-adrenoceptor antagonists, at doses that had no effect on the basal number of head-twitches (idazoxan 0.2 mg/kg and yohimbine 0.5 mg/kg), significantly attenuated not only the suppressive effect of clonidine (0.01 mg/kg, IP) on head-twitch response but also that of the 5-HT2 receptor antagonist ritanserin (0.03 mg/kg, IP). Moreover, idazoxan (0.2 mg/kg) also significantly reversed the inhibition by 0.01 mg/kg (IP) ketanserin, a selective 5-HT2 receptor antagonist. Pretreatment with 6-OHDA plus nomifensine but not with p-CPA significantly attenuated the effect of idazoxan (0.2-0.5 mg/kg) on the ritanserin inhibition of the head-twitch response. Prazosin, an alpha1-adrenoceptor antagonist, dose-dependently suppressed the response, and the effect of prazosin (1.25 mg/kg) was significantly attenuated by 0.5 mg/kg idazoxan. These results indicate that endogenous noradrenaline is involved in the apparent antagonistic interaction between selective alpha2-adrenoceptor antagonists and 5-HT2 receptor antagonists in the head-twitch response, and suggest that noradrenaline stimulation of alpha1-adrenoceptors may be involved in this apparent antagonism.

  5. Coal dust alters β-naphthoflavone-induced aryl hydrocarbon receptor nuclear translocation in alveolar type II cells

    Directory of Open Access Journals (Sweden)

    Castranova Vincent

    2009-08-01

    Full Text Available Abstract Background Many polycyclic aromatic hydrocarbons (PAHs can cause DNA adducts and initiate carcinogenesis. Mixed exposures to coal dust (CD and PAHs are common in occupational settings. In the CD and PAH-exposed lung, CD increases apoptosis and causes alveolar type II (AT-II cell hyperplasia but reduces CYP1A1 induction. Inflammation, but not apoptosis, appears etiologically associated with reduced CYP1A1 induction in this mixed exposure model. Many AT-II cells in the CD-exposed lungs have no detectable CYP1A1 induction after PAH exposure. Although AT-II cells are a small subfraction of lung cells, they are believed to be a potential progenitor cell for some lung cancers. Because CYP1A1 is induced via ligand-mediated nuclear translocation of the aryl hydrocarbon receptor (AhR, we investigated the effect of CD on PAH-induced nuclear translocation of AhR in AT-II cells isolated from in vivo-exposed rats. Rats received CD or vehicle (saline by intratracheal (IT instillation. Three days before sacrifice, half of the rats in each group started daily intraperitoneal injections of the PAH, β-naphthoflavone (BNF. Results Fourteen days after IT CD exposure and 1 day after the last intraperitoneal BNF injection, AhR immunofluorescence indicated that proportional AhR nuclear expression and the percentage of cells with nuclear AhR were significantly increased in rats receiving IT saline and BNF injections compared to vehicle controls. However, in CD-exposed rats, BNF did not significantly alter the nuclear localization or cytosolic expression of AhR compared to rats receiving CD and oil. Conclusion Our findings suggest that during particle and PAH mixed exposures, CD alters the BNF-induced nuclear translocation of AhR in AT-II cells. This provides an explanation for the modification of CYP1A1 induction in these cells. Thus, this study suggests that mechanisms for reduced PAH-induced CYP1A1 activity in the CD exposed lung include not only the

  6. Breast cancer stem-like cells are inhibited by a non-toxic aryl hydrocarbon receptor agonist.

    Directory of Open Access Journals (Sweden)

    Gérald J Prud'homme

    2010-11-01

    Full Text Available Cancer stem cells (CSCs have increased resistance to cancer chemotherapy. They can be enriched as drug-surviving CSCs (D-CSCs by growth with chemotherapeutic drugs, and/or by sorting of cells expressing CSC markers such as aldehyde dehydrogenase-1 (ALDH. CSCs form colonies in agar, mammospheres in low-adherence cultures, and tumors following xenotransplantation in Scid mice. We hypothesized that tranilast, a non-toxic orally active drug with anti-cancer activities, would inhibit breast CSCs.We examined breast cancer cell lines or D-CSCs generated by growth of these cells with mitoxantrone. Tranilast inhibited colony formation, mammosphere formation and stem cell marker expression. Mitoxantrone-selected cells were enriched for CSCs expressing stem cell markers ALDH, c-kit, Oct-4, and ABCG2, and efficient at forming mammospheres. Tranilast markedly inhibited mammosphere formation by D-CSCs and dissociated formed mammospheres, at pharmacologically relevant concentrations. It was effective against D-CSCs of both HER-2+ and triple-negative cell lines. Tranilast was also effective in vivo, since it prevented lung metastasis in mice injected i.v. with triple-negative (MDA-MB-231 mitoxantrone-selected cells. The molecular targets of tranilast in cancer have been unknown, but here we demonstrate it is an aryl hydrocarbon receptor (AHR agonist and this plays a key role. AHR is a transcription factor activated by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD, polycyclic aromatic hydrocarbons and other ligands. Tranilast induced translocation of the AHR to the nucleus and stimulated CYP1A1 expression (a marker of AHR activation. It inhibited binding of the AHR to CDK4, which has been linked to cell-cycle arrest. D-CSCs expressed higher levels of the AHR than other cells. Knockdown of the AHR with siRNA, or blockade with an AHR antagonist, entirely abrogated the anti-proliferative and anti-mammosphere activity of tranilast. Thus, the anti-cancer effects of

  7. Temporal variability of Polycyclic Aromatic Hydrocarbons in a receptor site of Puebla -Tlaxcala Valley.

    Science.gov (United States)

    Padilla Barrera, Zuhelen; Torres Jardón, Ricardo; Gerardo Ruiz, Luis; Castro, Telma

    2015-04-01

    The Puebla-Tlaxcala Valley is a region with high population scattered over two states, where emissions from combustion of a variety of materials and fuels represent a major problem in the deterioration of air quality. Polycyclic aromatic hydrocarbons (PAHs) are a class of semi-volatile organic compounds that are formed during combustion. PAH are present in large amounts in the particulate matter comes from the combustion and no combustion. The particle-bound PAHs are formed by accumulation and condensation mechanisms in the particle. In its condensed form are mainly associated with fine particles (< 0.10 um). The major emission sources of PAHs are open burning, industrial boilers and emission from cars and trucks. Emission rates of PAHs vary significantly depending on vehicle use: fuel type, engine type and catalytic converter, and once emitted into the atmosphere, particulate PAHs may undergo transformation by photo-oxidation. The measurements were made with a photoelectric aerosol sensor (PAS 2000 CE) and a diffusion charger (DC 2000 CE), the first determines the concentration of PAHs, while the second determines the active surface of particles. The use of these two sensors in parallel is a useful tool to identify quantitatively the greatest source of emission, describe the physical and chemical characteristics of the particles. Correlations between PAHs with the active surface (DC), NOy and CO, together with an analysis of weather atmospheric transport to approximate the possible origin of these particles. The coefficient PAHs / DC associated with the backward trajectory analysis is a tool to identify potential areas of emission. The correlation between PAHs and NOx reflects emissions associated with diesel combustion, while the correlation between PAHs and CO, combustion of gasoline. Concentration patterns were recorded over 24 hours in both PAHs and DC. The average concentration of PAHs was 4.9 ng/m3 and the maximum of 81.9 ng/m3 , while the average active

  8. Suppression of CB1 cannabinoid receptor by lentivirus mediated small interfering RNA ameliorates hepatic fibrosis in rats.

    Directory of Open Access Journals (Sweden)

    Si-Wen Chen

    Full Text Available It is recognized that endogenous cannabinoids, which signal through CB1 receptors in hepatic stellate cells (HSCs, exert a profibrotic effect on chronic liver diseases. In this study, we suppressed CB1 expression by lentivirus mediated small interfering RNA (CB1-RNAi-LV and investigated its effect on hepatic fibrosis in vitro and in vivo. Our results demonstrated that CB1-RNAi-LV significantly inhibited CB1 expression, and suppressed proliferation and extracellular matrix production in HSCs. Furthermore, CB1-RNAi-LV ameliorated dimethylnitrosamine induced hepatic fibrosis markedly, which was associated with the decreased expression of mesenchymal cell markers smooth muscle α-actin, vimentin and snail, and the increased expression of epithelial cell marker E-cadherin. The mechanism lies on the blockage of Smad signaling transduction induced by transforming growth factor β1 and its receptor TGF-β RII. Our study firstly provides the evidence that CB1-RNAi-LV might ameliorate hepatic fibrosis through the reversal of epithelial-to-mesenchymal transition (EMT, while the CB1 antagonists AM251 had no effect on epithelial-mesenchymal transitions of HSCs. This suggests that CB1 is implicated in hepatic fibrosis and selective suppression of CB1 by small interfering RNA may present a powerful tool for hepatic fibrosis treatment.

  9. Growth suppression by transforming growth factor beta 1 of human small-cell lung cancer cell lines is associated with expression of the type II receptor.

    Science.gov (United States)

    Nørgaard, P; Damstrup, L; Rygaard, K; Spang-Thomsen, M; Skovgaard Poulsen, H

    1994-05-01

    Nine human small-cell lung cancer cell lines were treated with transforming growth factor beta 1 (TGF-beta 1). Seven of the cell lines expressed receptors for transforming growth factor beta (TGF-beta-r) in different combinations between the three human subtypes I, II and III, and two were receptor negative. Growth suppression was induced by TGF-beta 1 exclusively in the five cell lines expressing the type II receptor. For the first time growth suppression by TGF-beta 1 of a cell line expressing the type II receptor without coexpression of the type I receptor is reported. No effect on growth was observed in two cell lines expressing only type III receptor and in TGF-beta-r negative cell lines. In two cell lines expressing all three receptor types, growth suppression was accompanied by morphological changes. To evaluate the possible involvement of the retinoblastoma protein (pRb) in mediating the growth-suppressive effect of TGF-beta 1, the expression of functional pRb, as characterised by nuclear localisation, was examined by immunocytochemistry. Nuclear association of pRb was only seen in two of the five TGF-beta 1-responsive cell lines. These results indicate that in SCLC pRb is not required for mediation of TGF-beta 1-induced growth suppression.

  10. Neural precursor cell proliferation is disrupted through activation of the aryl hydrocarbon receptor by 2,3,7,8-tetrachlorodibenzo-p-dioxin.

    Science.gov (United States)

    Latchney, Sarah E; Lioy, Daniel T; Henry, Ellen C; Gasiewicz, Thomas A; Strathmann, Frederick G; Mayer-Pröschel, Margot; Opanashuk, Lisa A

    2011-02-01

    Neurogenesis involves the proliferation of multipotent neuroepithelial stem cells followed by differentiation into lineage-restricted neural precursor cells (NPCs) during the embryonic period. Interestingly, these progenitor cells express robust levels of the aryl hydrocarbon receptor (AhR), a ligand-activated transcription factor that regulates expression of genes important for growth regulation, and xenobiotic metabolism. Upon binding 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), a pervasive environmental contaminant and potent AhR ligand, AhR, is activated and disrupts gene expression patterns to produce cellular toxicity. Because of its widespread distribution in the brain during critical proliferative phases of neurogenesis, it is conceivable that AhR participates in NPC expansion. Therefore, this study tested the hypothesis that AhR activation by TCDD disrupts signaling events that regulate NPC proliferation. The C17.2 NPC line served as a model system to (1) assess whether NPCs are targets for TCDD-induced neurotoxicity and (2) characterize the effects of TCDD on NPC proliferation. We demonstrated that C17.2 NPCs express an intact AhR signaling pathway that becomes transcriptionally active after TCDD exposure. (3)H-thymidine and alamar blue reduction assays indicated that TCDD suppresses NPC proliferation in a concentration-dependent manner without the loss of cell viability. Cell cycle distribution analysis by flow cytometry revealed that TCDD-induced growth arrest results from an impaired G1 to S cell cycle transition. Moreover, TCDD exposure altered p27( kip1) and cyclin D1 cell cycle regulatory protein expression levels consistent with a G1 phase arrest. Initial studies in primary NPCs isolated from the ventral forebrain of embryonic mice demonstrated that TCDD reduced cell proliferation through a G1 phase arrest, corroborating our findings in the C17.2 cell line. Together, these observations suggest that the inappropriate or sustained activation of Ah

  11. Differential Effects of Omeprazole and Lansoprazole Enantiomers on Aryl Hydrocarbon Receptor in Human Hepatocytes and Cell Lines

    Science.gov (United States)

    Novotna, Aneta; Srovnalova, Alzbeta; Svecarova, Michaela; Korhonova, Martina; Bartonkova, Iveta; Dvorak, Zdenek

    2014-01-01

    Proton pump inhibitors omeprazole and lansoprazole contain chiral sulfur atom and they are administered as a racemate, i.e. equimolar mixture of S- and R-enantiomers. The enantiopure drugs esomeprazole and dexlansoprazole have been developed and introduced to clinical practice due to their improved clinical and therapeutic properties. Since omeprazole and lansoprazole are activators of aryl hydrocarbon receptor (AhR) and inducers of CYP1A genes, we examined their enantiospecific effects on AhR-CYP1A pathway in human cancer cells and primary human hepatocytes. We performed gene reporter assays for transcriptional activity of AhR, RT-PCR analyses for CYP1A1/2 mRNAs, western blots for CYP1A1/2 proteins and EROD assay for CYP1A1/2 catalytic activity. Lansoprazole and omeprazole enantiomers displayed differential effects on AhR-CYP1A1/2 pathway. In general, S-enantiomers were stronger activators of AhR and inducers of CYP1A genes as compared to R-enantiomers in lower concentrations, i.e. 1–10 µM for lansoprazole and 10–100 µM for omeprazole. In contrast, R-enantiomers were stronger AhR activators and CYP1A inducers than S-enantiomers in higher concentrations, i.e. 100 µM for lansoprazole and 250 µM for omeprazole. In conclusion, we provide the first evidence of enantiospecific effects of omeprazole and lansoprazole on AhR signaling pathway. PMID:24887303

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

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Xingguo, E-mail: chengx@stjohns.edu [Department of Pharmaceutical Sciences, St. John' s University, 8000 Utopia Parkway, Queens, NY 11439 (United States); Vispute, Saurabh G. [Department of Pharmaceutical Sciences, St. John' s University, 8000 Utopia Parkway, Queens, NY 11439 (United States); Liu, Jie [Department of Internal Medicine, University of Kansas Medical Center, 3901 Rainbow Boulevard, Kansas City, KS 66160 (United States); Cheng, Christine; Kharitonenkov, Alexei [Lilly Research Laboratories, Division of Eli Lilly and Co., Indianapolis, IN 46285 (United States); Klaassen, Curtis D., E-mail: curtisklaassenphd@gmail.com [Department of Internal Medicine, University of Kansas Medical Center, 3901 Rainbow Boulevard, Kansas City, KS 66160 (United States)

    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.

  13. Association between glycodelin and aryl hydrocarbon receptor in Iranian breast cancer patients: impact of environmental endocrine disrupting chemicals.

    Science.gov (United States)

    Bidgoli, Sepideh Arbabi; Korani, Mitra; Bozorgi, Niloofar; Zavarhei, Mansour Djamali; Ziarati, Parisa; Akbarzadeh, Saeed

    2011-01-01

    Breast cancer affects Iranian women one decade younger than their counterparts in other countries and the underlying risk factors have remained controversial. The aryl hydrocarbon receptor (AhR) mediates the effects of many environmental endocrine disruptors and contributes to the many other genes and Gd is an endocrine-regulated glycoprotein which may induce by AhR ligands in endometrium. This study has aimed to compare the interactions between Gd and AhR and other fundamental genes (p53, K-Ras, ER, PgR, AR) between pre and post menopausal Iranian breast cancer patients. To conduct immunohistochemical studies with appropriate monoclonal antibodies, 25 premenopausal invasive ductal carcinomas and 29 postmenopausal invasive ductal carcinomas were selected retrospectively in 2008-2010 from the pathology department of Imam Khomeini hospital complex of Tehran. Higher levels of AhR in epithelial cells of premenopausal patients and breast fibroadenoma emphasized the susceptibility of these cells to environmental induced tumors. Current study demonstrated a significant association between tumoral levels of Gd and AhR (p=0.002) in breast cancers which confirms the preliminary hypothesis about the role of TCDD exposure on Gd biosynthesis and secretion in TCDD-treated endometrial epithelial cells. In summary this study showed the dual prognostic role of Gd especially in premenopausal breast cancer which could be induced by AhR overexpression. Further studies are necessary to find the direct role of breast carcinogens as well as endocrine disrupting chemicals on the differential levels of Gd in breast tumors.

  14. Differential effects of omeprazole and lansoprazole enantiomers on aryl hydrocarbon receptor in human hepatocytes and cell lines.

    Science.gov (United States)

    Novotna, Aneta; Srovnalova, Alzbeta; Svecarova, Michaela; Korhonova, Martina; Bartonkova, Iveta; Dvorak, Zdenek

    2014-01-01

    Proton pump inhibitors omeprazole and lansoprazole contain chiral sulfur atom and they are administered as a racemate, i.e. equimolar mixture of S- and R-enantiomers. The enantiopure drugs esomeprazole and dexlansoprazole have been developed and introduced to clinical practice due to their improved clinical and therapeutic properties. Since omeprazole and lansoprazole are activators of aryl hydrocarbon receptor (AhR) and inducers of CYP1A genes, we examined their enantiospecific effects on AhR-CYP1A pathway in human cancer cells and primary human hepatocytes. We performed gene reporter assays for transcriptional activity of AhR, RT-PCR analyses for CYP1A1/2 mRNAs, western blots for CYP1A1/2 proteins and EROD assay for CYP1A1/2 catalytic activity. Lansoprazole and omeprazole enantiomers displayed differential effects on AhR-CYP1A1/2 pathway. In general, S-enantiomers were stronger activators of AhR and inducers of CYP1A genes as compared to R-enantiomers in lower concentrations, i.e. 1-10 µM for lansoprazole and 10-100 µM for omeprazole. In contrast, R-enantiomers were stronger AhR activators and CYP1A inducers than S-enantiomers in higher concentrations, i.e. 100 µM for lansoprazole and 250 µM for omeprazole. In conclusion, we provide the first evidence of enantiospecific effects of omeprazole and lansoprazole on AhR signaling pathway.

  15. Aryl Hydrocarbon Receptor (AhR Modulates Cockroach Allergen-Induced Immune Responses through Active TGFβ1 Release

    Directory of Open Access Journals (Sweden)

    Yufeng Zhou

    2014-01-01

    Full Text Available Background. Aryl hydrocarbon receptor (AhR, a multifunctional regulator that senses and responds to environmental stimuli, plays a role in normal cell development and immune regulation. Recent evidence supports a significant link between environmental exposure and AhR in the development of allergic diseases. We sought to investigate whether AhR plays a role in mediating cockroach allergen-induced allergic immune responses. Methods. AhR expression in human lung fibroblasts from asthmatic and healthy individuals and in cockroach extract (CRE treated human lung fibroblasts (WI-38 was examined. The role of AhR in modulating CRE induced TGFβ1 production was investigated by using AhR agonist, TCDD, antagonist CH122319, and knockdown of AhR. The role of latent TGFβ1 binding protein-1 (LTBP1 in mediating TCDD induced active TGFβ1 release was also examined. Results. AhR expression was higher in airway fibroblasts from asthmatic subjects as compared to healthy controls. AhR in fibroblasts was activated by TCDD with an increased expression of cyp1a1 and cyp1b1. Increased AhR expression was observed in CRE-treated fibroblasts. Importantly, CRE induced TGFβ1 production in fibroblasts was significantly enhanced by TCDD but inhibited by CH122319. Reduced TGFβ1 production was further confirmed in fibroblasts with AhR knockdown. Moreover, AhR knockdown inhibited CRE induced fibroblast differentiation. Furthermore, TCDD induced active TGFβ1 release was significantly inhibited by LTBP1 knockdown. Conclusion. These results provide evidence for the role of AhR in modulating cockroach allergen-induced immune responses through controlling the active TGFβ1 release, suggesting a possible synergistic effect between exposure to allergens and environmental chemicals on the development of allergic diseases.

  16. Galactomyces fermentation filtrate prevents T helper 2-mediated reduction of filaggrin in an aryl hydrocarbon receptor-dependent manner.

    Science.gov (United States)

    Takei, K; Mitoma, C; Hashimoto-Hachiya, A; Takahara, M; Tsuji, G; Nakahara, T; Furue, M

    2015-10-01

    The aryl hydrocarbon receptor (AhR) recognizes diverse small molecules such as dioxins, tryptophan photoproducts and phytochemicals. It also plays crucial roles in epidermal homeostasis by upregulating epidermal barrier proteins. In preliminary screening, we found that Galactomyces fermentation filtrate (GFF), a cosmetic compound, was capable of activating AhR. To examine whether GFF upregulates the expression of the filaggrin and loricrin genes, FLG and LOR, in an AhR-dependent manner. The activation (cytoplasmic to nuclear translocation) of AhR was confirmed by immunofluorescence study and by upregulation of an AhR-specific marker, cytochrome P450-1A1 (CYP1A1). Gene expression levels were compared by quantitative reverse transcription PCR with or without GFF, interleukin (IL)-4 or IL-13 in normal human keratinocytes. AhR or control knockdown was carried out by transfection with AhR or control small interfering RNA. The protein expression of FLG and LOR was examined by immunohistochemistry using a three-dimensional epidermal equivalent treated with or without GFF or T helper (Th)2 cytokines. GFF induced the nuclear translocation of AhR with significant and dose-dependent upregulation of CYP1A1, FLG and LOR gene expression. The enhancing effects of GFF were abolished in AhR-knockdown keratinocytes. Th2 cytokines decreased expression of genes for FLG and LOR, and this expression was completely restored in the presence of GFF. The downregulated expression of the FLG gene with its restoration by GFF was also evident in the epidermal equivalent. GFF also upregulated the gene expression of genes encoding occludin, claudin-1 and 4, and kallikrein 5 and 7. Use of GFF is feasible to prevent the Th2-mediated reduction of FLG in an AhR-dependent fashion. © 2015 The Authors Clinical and Experimental Dermatology published by John Wiley & Sons Ltd on behalf of British Association of Dermatologists, North American Clinical Dermatologic Society and St Johns Dermatological

  17. Aryl hydrocarbon receptor (AHR-regulated transcriptomic changes in rats sensitive or resistant to major dioxin toxicities

    Directory of Open Access Journals (Sweden)

    Okey Allan B

    2010-04-01

    Full Text Available Abstract Background The major toxic effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD appear to result from dysregulation of mRNA levels mediated by the aryl hydrocarbon receptor (AHR. Dioxin-like chemicals alter expression of numerous genes in liver, but it remains unknown which lie in pathways leading to major toxicities such as hepatotoxicity, wasting and lethality. To identify genes involved in these responses we exploited a rat genetic model. Rats expressing an AHR splice-variant lacking a portion of the transactivation domain are highly resistant to dioxin-induced toxicities. We examined changes in hepatic mRNA abundances 19 hours after TCDD treatment in two dioxin-resistant rat strains/lines and two dioxin-sensitive rat strains/lines. Results Resistant rat strains/lines exhibited fewer transcriptional changes in response to TCDD than did rats with wildtype AHR. However, well-known AHR-regulated and dioxin-inducible genes such as CYP1A1, CYP1A2, and CYP1B1 remained fully responsive to TCDD in all strains/lines. Pathway analysis indicated that the genes which respond differently to TCDD between sensitive and resistant rats are mainly involved in lipid metabolism, cellular membrane function and energy metabolism. These pathways previously have been shown to respond differently to dioxin treatment in dioxin-sensitive versus dioxin-resistant rats at a biochemical level and in the differential phenotype of toxicologic responses. Conclusion The transactivation-domain deletion in dioxin-resistant rats does not abolish global AHR transactivational activity but selectively interferes with expression of subsets of genes that are candidates to mediate or protect from major dioxin toxicities such as hepatotoxicity, wasting and death.

  18. Uremic Solute-Aryl Hydrocarbon Receptor-Tissue Factor Axis Associates with Thrombosis after Vascular Injury in Humans.

    Science.gov (United States)

    Kolachalama, Vijaya B; Shashar, Moshe; Alousi, Faisal; Shivanna, Sowmya; Rijal, Keshab; Belghasem, Mostafa E; Walker, Joshua; Matsuura, Shinobu; Chang, Gary H; Gibson, C Michael; Dember, Laura M; Francis, Jean M; Ravid, Katya; Chitalia, Vipul C

    2018-01-17

    Individuals with CKD are particularly predisposed to thrombosis after vascular injury. Using mouse models, we recently described indoxyl sulfate, a tryptophan metabolite retained in CKD and an activator of tissue factor (TF) through aryl hydrocarbon receptor (AHR) signaling, as an inducer of thrombosis across the CKD spectrum. However, the translation of findings from animal models to humans is often challenging. Here, we investigated the uremic solute-AHR-TF thrombosis axis in two human cohorts, using a targeted metabolomics approach to probe a set of tryptophan products and high-throughput assays to measure AHR and TF activity. Analysis of baseline serum samples was performed from 473 participants with advanced CKD from the Dialysis Access Consortium Clopidogrel Prevention of Early AV Fistula Thrombosis trial. Participants with subsequent arteriovenous thrombosis had significantly higher levels of indoxyl sulfate and kynurenine, another uremic solute, and greater activity of AHR and TF, than those without thrombosis. Pattern recognition analysis using the components of the thrombosis axis facilitated clustering of the thrombotic and nonthrombotic groups. We further validated these findings using 377 baseline samples from participants in the Thrombolysis in Myocardial Infarction II trial, many of whom had CKD stage 2-3. Mechanistic probing revealed that kynurenine enhances thrombosis after vascular injury in an animal model and regulates thrombosis in an AHR-dependent manner. This human validation of the solute-AHR-TF axis supports further studies probing its utility in risk stratification of patients with CKD and exploring its role in other diseases with heightened risk of thrombosis. Copyright © 2018 by the American Society of Nephrology.

  19. Melatonin acts through MT1/MT2 receptors to activate hypothalamic Akt and suppress hepatic gluconeogenesis in rats.

    Science.gov (United States)

    Faria, Juliana A; Kinote, Andrezza; Ignacio-Souza, Letícia M; de Araújo, Thiago M; Razolli, Daniela S; Doneda, Diego L; Paschoal, Lívia B; Lellis-Santos, Camilo; Bertolini, Gisele L; Velloso, Lício A; Bordin, Silvana; Anhê, Gabriel F

    2013-07-15

    Melatonin can contribute to glucose homeostasis either by decreasing gluconeogenesis or by counteracting insulin resistance in distinct models of obesity. However, the precise mechanism through which melatonin controls glucose homeostasis is not completely understood. Male Wistar rats were administered an intracerebroventricular (icv) injection of melatonin and one of following: an icv injection of a phosphatidylinositol 3-kinase (PI3K) inhibitor, an icv injection of a melatonin receptor (MT) antagonist, or an intraperitoneal (ip) injection of a muscarinic receptor antagonist. Anesthetized rats were subjected to pyruvate tolerance test to estimate in vivo glucose clearance after pyruvate load and in situ liver perfusion to assess hepatic gluconeogenesis. The hypothalamus was removed to determine Akt phosphorylation. Melatonin injections in the central nervous system suppressed hepatic gluconeogenesis and increased hypothalamic Akt phosphorylation. These effects of melatonin were suppressed either by icv injections of PI3K inhibitors and MT antagonists and by ip injection of a muscarinic receptor antagonist. We conclude that melatonin activates hypothalamus-liver communication that may contribute to circadian adjustments of gluconeogenesis. These data further suggest a physiopathological relationship between the circadian disruptions in metabolism and reduced levels of melatonin found in type 2 diabetes patients.

  20. Probing the effector and suppressive functions of human T cell subsets using antigen-specific engineered T cell receptors.

    Science.gov (United States)

    Wan, Qi; Kozhaya, Lina; Imberg, Keren; Mercer, Frances; Zhong, Shi; Krogsgaard, Michelle; Unutmaz, Derya

    2013-01-01

    Activation of T cells through the engagement of the T cell receptors (TCRs) with specific peptide-MHC complexes on antigen presenting cells (APCs) is the major determinant for their proliferation, differentiation and display of effector functions. To assess the role of quantity and quality of peptide-MHC presentation in eliciting T cell activation and suppression functions, we genetically engineered human T cells with two TCRs that recognize HLA-A*0201-restricted peptides derived from either HIV or melanoma antigens. The engineered-TCRs are highly functional in both CD8(+) and CD4(+) T cells as assessed by the upregulation of activation markers, induction of cytokine secretion and cytotoxicity. We further demonstrated that engineered-TCRs can also be expressed on naïve human T cells, which are stimulated through APCs presenting specific peptides to induce T cell proliferation and acquire effector functions. Furthermore, regulatory T cells (Tregs) ectopically expressing the engineered-TCRs are activated in an antigen-specific fashion and suppress T cell proliferation. In this system, the inhibitory activity of peptide-stimulated Tregs require the presence of dendritic cells (DCs) in the culture, either as presenters or as bystander cells, pointing to a critical role for DCs in suppression by Tregs. In conclusion, the engineered-TCR system reported here advances our ability to understand the differentiation pathways of naïve T cells into antigen-specific effector cells and the role of antigen-specific signaling in Treg-mediated immune suppression.

  1. Suppression of NMDA receptor function in mice prenatally exposed to valproic acid improves social deficits and repetitive behaviors

    Directory of Open Access Journals (Sweden)

    Jaeseung eKang

    2015-05-01

    Full Text Available Animals prenatally exposed to valproic acid (VPA, an antiepileptic agent, have been used as a model for autism spectrum disorders (ASDs. Previous studies have identified enhanced NMDA receptor (NMDAR function in the brain of VPA rats, and demonstrated that pharmacological suppression of NMDAR function normalizes social deficits in these animals. However, whether repetitive behavior, another key feature of ASDs, can be rescued by NMDAR inhibition remains unknown. We report here that memantine, an NMDAR antagonist, administered to VPA mice rescues both social deficits and repetitive behaviors such as self-grooming and jumping. These results suggest that suppression of elevated NMDAR function in VPA animals normalizes repetitive behaviors in addition to social deficits.

  2. The aryl hydrocarbon receptor and estrogen receptor alpha differentially modulate nuclear factor erythroid-2-related factor 2 transactivation in MCF-7 breast cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Lo, Raymond; Matthews, Jason, E-mail: jason.matthews@utoronto.ca

    2013-07-15

    Nuclear factor erythroid-2-related factor 2 (NRF2; NFE2L2) plays an important role in mediating cellular protection against reactive oxygen species. NRF2 signaling is positively modulated by the aryl hydrocarbon receptor (AHR) but inhibited by estrogen receptor alpha (ERα). In this study we investigated the crosstalk among NRF2, AHR and ERα in MCF-7 breast cancer cells treated with the NRF2 activator sulforaphane (SFN), a dual AHR and ERα activator, 3,3′-diindolylmethane (DIM), 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) or 17β-estradiol (E2). SFN-dependent increases in NADPH-dependent oxidoreductase 1 (NQO1) and heme oxygenase I (HMOX1) mRNA levels were significantly reduced after co-treatment with E2. E2-dependent repression of NQO1 and HMOX1 was associated with increased ERα but reduced p300 recruitment and reduced histone H3 acetylation at both genes. In contrast, DIM + SFN or TCDD + SFN induced NQO1 and HMOX1 mRNA expression to levels higher than SFN alone, which was prevented by RNAi-mediated knockdown of AHR. DIM + SFN but not TCDD + SFN also induced recruitment of ERα to NQO1 and HMOX1. However, the presence of AHR at NQO1 and HMOX1 restored p300 recruitment and histone H3 acetylation, thereby reversing the ERα-dependent repression of NRF2. Taken together, our study provides further evidence of functional interplay among NRF2, AHR and ERα signaling pathways through altered p300 recruitment to NRF2-regulated target genes. - Highlights: • We examined crosstalk among ERα, AHR, and NRF2 in MCF-7 breast cancer cells. • AHR enhanced the mRNA expression levels of two NRF2 target genes – HMOX1 and NQO1. • ERα repressed HMOX1 and NQO1 expression via decreased histone acetylation. • AHR prevented ERα-dependent repression of HMOX1 and NQO1.

  3. Growth suppression by transforming growth factor beta 1 of human small-cell lung cancer cell lines is associated with expression of the type II receptor.

    OpenAIRE

    N?rgaard, P.; Damstrup, L; Rygaard, K; Spang-Thomsen, M.; Skovgaard Poulsen, H.

    1994-01-01

    Nine human small-cell lung cancer cell lines were treated with transforming growth factor beta 1 (TGF-beta 1). Seven of the cell lines expressed receptors for transforming growth factor beta (TGF-beta-r) in different combinations between the three human subtypes I, II and III, and two were receptor negative. Growth suppression was induced by TGF-beta 1 exclusively in the five cell lines expressing the type II receptor. For the first time growth suppression by TGF-beta 1 of a cell line express...

  4. Differential suppression of seizures via Y2 and Y5 neuropeptide Y receptors

    DEFF Research Database (Denmark)

    Woldbye, David P D; Nanobashvili, Avtandil; Sørensen, Andreas Vehus

    2005-01-01

    Neuropeptide Y (NPY) prominently inhibits epileptic seizures in different animal models. The NPY receptors mediating this effect remain controversial partially due to lack of highly selective agonists and antagonists. To circumvent this problem, we used various NPY receptor knockout mice with the...

  5. PAC down-regulates estrogen receptor alpha and suppresses epithelial-to-mesenchymal transition in breast cancer cells.

    Science.gov (United States)

    Al-Howail, Huda A; Hakami, Hana A; Al-Otaibi, Basem; Al-Mazrou, Amer; Daghestani, Maha H; Al-Jammaz, Ibrahim; Al-Khalaf, Huda H; Aboussekhra, Abdelilah

    2016-07-27

    Triple-negative breast cancer (TNBC) is an aggressive histological subtype with limited treatment options and very poor prognosis following progression after standard chemotherapeutic regimens. Therefore, novel molecules and therapeutic options are urgently needed for this category of patients. Recently, we have identified PAC as a curcumin analogue with potent anti-cancer features. HPLC was used to evaluate the stability of PAC and curcumin in PBS and also in circulating blood. Cytotoxicity/apoptosis was assessed in different breast cancer cell lines using propidium iodide/annexinV associated with flow cytometry. Furthermore, immunoblotting analysis determined the effects of PAC on different oncogenic proteins and pathways. Additionally, the real time xCELLigence RTCA technology was applied to investigate the effect of PAC on the cellular proliferation, migration and invasion capacities. PAC is more stable than curcumin in PBS and in circulating blood. Furthermore, we have shown differential sensitivity of estrogen receptor-alfa positive (ERα(+)) and estrogen receptor alfa negative (ERα(-)) breast cancer cells to PAC, which down-regulated ERα in both cell types. This led to complete disappearance of ERα in ERα(-) cells, which express very low level of this receptor. Interestingly, specific down-regulation of ERα in receptor positive cells increased the apoptotic response of these cells to PAC, confirming that ERα inhibits PAC-dependent induction of apoptosis, which could be mediated through ERα down-regulation. Additionally, PAC inhibited the proliferation and suppressed the epithelial-to-mesenchymal transition process in breast cancer cells, with higher efficiency on the TNBC subtype. This effect was also observed in vivo on tumor xenografts. Additionally, PAC suppressed the expression/secretion of 2 important cytokines IL-6 and MCP-1, and consequently inhibited the paracrine procarcinogenic effects of breast cancer cells on breast stromal fibroblasts

  6. Knockout of the aryl hydrocarbon receptor results in distinct hepatic and renal phenotypes in rats and mice

    Energy Technology Data Exchange (ETDEWEB)

    Harrill, Joshua A. [The Hamner Institute for Health Sciences, Institute for Chemical Safety Sciences, RTP, NC 27709 (United States); Hukkanen, Renee R.; Lawson, Marie; Martin, Greg [The Dow Chemical Company, Midland, MI 48640 (United States); Gilger, Brian [North Carolina State University, College of Veterinary Medicine, Raleigh, NC 27606 (United States); Soldatow, Valerie [University of North Carolina, Department of Environmental Sciences and Engineering, Chapel Hill, NC 27599 (United States); LeCluyse, Edward L. [The Hamner Institute for Health Sciences, Institute for Chemical Safety Sciences, RTP, NC 27709 (United States); Budinsky, Robert A.; Rowlands, J. Craig [The Dow Chemical Company, Midland, MI 48640 (United States); Thomas, Russell S., E-mail: RThomas@thehamner.org [The Hamner Institute for Health Sciences, Institute for Chemical Safety Sciences, RTP, NC 27709 (United States)

    2013-10-15

    The aryl hydrocarbon receptor (AHR) is a ligand-activated transcription factor which plays a role in the development of multiple tissues and is activated by a large number of ligands, including 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). In order to examine the roles of the AHR in both normal biological development and response to environmental chemicals, an AHR knockout (AHR-KO) rat model was created and compared with an existing AHR-KO mouse. AHR-KO rats harboring either 2-bp or 29-bp deletion mutation in exon 2 of the AHR were created on the Sprague–Dawley genetic background using zinc-finger nuclease (ZFN) technology. Rats harboring either mutation type lacked expression of AHR protein in the liver. AHR-KO rats were also insensitive to thymic involution, increased hepatic weight and the induction of AHR-responsive genes (Cyp1a1, Cyp1a2, Cyp1b1, Ahrr) following acute exposure to 25 μg/kg TCDD. AHR-KO rats had lower basal expression of transcripts for these genes and also accumulated ∼ 30–45-fold less TCDD in the liver at 7 days post-exposure. In untreated animals, AHR-KO mice, but not AHR-KO rats, had alterations in serum analytes indicative of compromised hepatic function, patent ductus venosus of the liver and persistent hyaloid arteries in the eye. AHR-KO rats, but not AHR-KO mice, displayed pathological alterations to the urinary tract: bilateral renal dilation (hydronephrosis), secondary medullary tubular and uroepithelial degenerative changes and bilateral ureter dilation (hydroureter). The present data indicate that the AHR may play significantly different roles in tissue development and homeostasis and toxicity across rodent species. - Highlights: • An AHR knockout rat was generated on a Sprague–Dawley outbred background. • AHR-KO rats lack expression of AHR protein. • AHR-KO rats are insensitive to TCDD-mediated effects. • Data suggests difference in the role of AHR in tissue development of rats and mice. • Abnormalities in vascular

  7. Devil's Claw to suppress appetite--ghrelin receptor modulation potential of a Harpagophytum procumbens root extract.

    Directory of Open Access Journals (Sweden)

    Cristina Torres-Fuentes

    Full Text Available Ghrelin is a stomach-derived peptide that has been identified as the only circulating hunger hormone that exerts a potent orexigenic effect via activation of its receptor, the growth hormone secretagogue receptor (GHS-R1a. Hence, the ghrelinergic system represents a promising target to treat obesity and obesity-related diseases. In this study we analysed the GHS-R1a receptor activating potential of Harpagophytum procumbens, popularly known as Devil's Claw, and its effect on food intake in vivo. H. procumbens is an important traditional medicinal plant from Southern Africa with potent anti-inflammatory and analgesic effects. This plant has been also used as an appetite modulator but most evidences are anecdotal and to our knowledge, no clear scientific studies relating to appetite modulation have been done to this date. The ghrelin receptor activation potential of an extract derived from the dried tuberous roots of H. procumbens was analysed by calcium mobilization and receptor internalization assays in human embryonic kidney cells (Hek stably expressing the GHS-R1a receptor. Food intake was investigated in male C57BL/6 mice following intraperitoneal administration of H. procumbens root extract in ad libitum and food restricted conditions. Exposure to H. procumbens extract demonstrated a significant increased cellular calcium influx but did not induce subsequent GHS-R1a receptor internalization, which is a characteristic for full receptor activation. A significant anorexigenic effect was observed in male C57BL/6 mice following peripheral administration of H. procumbens extract. We conclude that H. procumbens root extract is a potential novel source for potent anti-obesity bioactives. These results reinforce the promising potential of natural bioactives to be developed into functional foods with weight-loss and weight maintenance benefits.

  8. Theobromine suppresses adipogenesis through enhancement of CCAAT-enhancer-binding protein β degradation by adenosine receptor A1.

    Science.gov (United States)

    Mitani, Takakazu; Watanabe, Shun; Yoshioka, Yasukiyo; Katayama, Shigeru; Nakamura, Soichiro; Ashida, Hitoshi

    2017-12-01

    Theobromine, a methylxanthine derived from cacao beans, reportedly has various health-promoting properties but molecular mechanism by which effects of theobromine on adipocyte differentiation and adipogenesis remains unclear. In this study, we aimed to clarify the molecular mechanisms of the anti-adipogenic effect of theobromine in vitro and in vivo. ICR mice (4week-old) were administered with theobromine (0.1g/kg) for 7days. Theobromine administration attenuated gains in body and epididymal adipose tissue weights in mice and suppressed expression of adipogenic-associated genes in mouse adipose tissue. In 3T3-L1 preadipocytes, theobromine caused degradation of C/EBPβ protein by the ubiquitin-proteasome pathway. Pull down assay showed that theobromine selectively interacts with adenosine receptor A1 (AR1), and AR1 knockdown inhibited theobromine-induced C/EBPβ degradation. Theobromine increased sumoylation of C/EBPβ at Lys133. Expression of the small ubiquitin-like modifier (SUMO)-specific protease 2 (SENP2) gene, coding for a desumoylation enzyme, was suppressed by theobromine. In vivo knockdown studies showed that AR1 knockdown in mice attenuated the anti-adipogenic effects of theobromine in younger mice. Theobromine suppresses adipocyte differentiation and induced C/EBPβ degradation by increasing its sumoylation. Furthermore, the inhibition of AR1 signaling is important for theobromine-induced C/EBPβ degradation. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Endogenous activation of adenosine A(1) receptors accelerates ischemic suppression of spontaneous electrocortical activity

    DEFF Research Database (Denmark)

    Ilie, Andrei; Ciocan, Dragos; Zagrean, Ana-Maria

    2006-01-01

    Cerebral ischemia induces a rapid suppression of spontaneous brain rhythms prior to major alterations in ionic homeostasis. It was found in vitro during ischemia that the rapidly formed adenosine, resulting from the intracellular breakdown of ATP, may inhibit synaptic transmission via the A(1...

  10. Chronic intermittent hypoxia induces NMDA receptor-dependent plasticity and suppresses nitric oxide signaling in the mouse hypothalamic paraventricular nucleus.

    Science.gov (United States)

    Coleman, Christal G; Wang, Gang; Park, Laibaik; Anrather, Josef; Delagrammatikas, George J; Chan, June; Zhou, Joan; Iadecola, Costantino; Pickel, Virginia M

    2010-09-08

    Chronic intermittent hypoxia (CIH) is a concomitant of sleep apnea that produces a slowly developing chemosensory-dependent blood pressure elevation ascribed in part to NMDA receptor-dependent plasticity and reduced nitric oxide (NO) signaling in the carotid body. The hypothalamic paraventricular nucleus (PVN) is responsive to hypoxic stress and also contains neurons that express NMDA receptors and neuronal nitric oxide synthase (nNOS). We tested the hypothesis that extended (35 d) CIH results in a decrease in the surface/synaptic availability of the essential NMDA NR1 subunit in nNOS-containing neurons and NMDA-induced NO production in the PVN of mice. As compared with controls, the 35 d CIH-exposed mice showed a significant increase in blood pressure and an increased density of NR1 immunogold particles located in the cytoplasm of nNOS-containing dendrites. Neither of these between-group differences was seen after 14 d, even though there was already a reduction in the NR1 plasmalemmal density at this time point. Patch-clamp recording of PVN neurons in slices showed a significant reduction in NMDA currents after either 14 or 35 d exposure to CIH compared with sham controls. In contrast, NO production, as measured by the NO-sensitive fluorescent dye 4-amino-5-methylamino-2',7'-difluorofluorescein, was suppressed only in the 35 d CIH group. We conclude that CIH produces a reduction in the surface/synaptic targeting of NR1 in nNOS neurons and decreases NMDA receptor-mediated currents in the PVN before the emergence of hypertension, the development of which may be enabled by suppression of NO signaling in this brain region.

  11. Complement Receptor Type 1 Suppresses Human B Cell Functions in SLE Patients

    Directory of Open Access Journals (Sweden)

    Mariann Kremlitzka

    2016-01-01

    Full Text Available Complement receptors (CRs play an integral role in innate immunity and also function to initiate and shape the adaptive immune response. Our earlier results showed that complement receptor type 1 (CR1, CD35 is a potent inhibitor of the B cell receptor- (BCR- induced functions of human B lymphocytes. Here we show that this inhibition occurs already at the initial steps of B cell activation since ligation of CR1 reduces the BCR-induced phosphorylation of key signaling molecules such as Syk and mitogen activated protein kinases (MAPKs. Furthermore, our data give evidence that although B lymphocytes of active systemic lupus erythematosus (SLE patients express lower level of CR1, the inhibitory capacity of this complement receptor is still maintained and its ligand-induced clustering results in significant inhibition of the main B cell functions, similar to that found in the case of healthy individuals. Since we have found that reduced CR1 expression of SLE patients does not affect the inhibitory capacity of the receptor, our results further support the therapeutical potential of CD35 targeting the decrease of B cell activation and autoantibody production in autoimmune patients.

  12. Complement Receptor Type 1 Suppresses Human B Cell Functions in SLE Patients.

    Science.gov (United States)

    Kremlitzka, Mariann; Mácsik-Valent, Bernadett; Polgár, Anna; Kiss, Emese; Poór, Gyula; Erdei, Anna

    2016-01-01

    Complement receptors (CRs) play an integral role in innate immunity and also function to initiate and shape the adaptive immune response. Our earlier results showed that complement receptor type 1 (CR1, CD35) is a potent inhibitor of the B cell receptor- (BCR-) induced functions of human B lymphocytes. Here we show that this inhibition occurs already at the initial steps of B cell activation since ligation of CR1 reduces the BCR-induced phosphorylation of key signaling molecules such as Syk and mitogen activated protein kinases (MAPKs). Furthermore, our data give evidence that although B lymphocytes of active systemic lupus erythematosus (SLE) patients express lower level of CR1, the inhibitory capacity of this complement receptor is still maintained and its ligand-induced clustering results in significant inhibition of the main B cell functions, similar to that found in the case of healthy individuals. Since we have found that reduced CR1 expression of SLE patients does not affect the inhibitory capacity of the receptor, our results further support the therapeutical potential of CD35 targeting the decrease of B cell activation and autoantibody production in autoimmune patients.

  13. Glucocorticoid receptor mediated suppression of natural killer cell activity: identification of associated deacetylase and corepressor molecules.

    Science.gov (United States)

    Bush, Kristin A; Krukowski, Karen; Eddy, Justin L; Janusek, Linda Witek; Mathews, Herbert L

    2012-01-01

    Physical and psychological stressors reduce natural killer cell function. This reduction in cellular function results from stress-induced release of glucocorticoids. Glucocorticoids act upon natural killer cells to deacetylate and transrepress immune response genes through epigenetic processes. However, other than the glucocorticoid receptor, the proteins that participate in this process are not well described in natural killer cells. The purpose of this study was to identify the proteins associated with the glucocorticoid receptor that are likely epigenetic participants in this process. Treatment of natural killer cells with the synthetic glucocorticoid, dexamethasone, produced a significant time dependent reduction in natural killer cell activity as early as 8h post treatment. This reduction in natural killer cell activity was preceded by nuclear localization of the glucocorticoid receptor with histone deacetylase 1 and the corepressor, SMRT. Other class I histone deacetylases were not associated with the glucocorticoid receptor nor was the corepressor NCoR. These results demonstrate histone deacetylase 1 and SMRT to associate with the ligand activated glucocorticoid receptor within the nuclei of natural killer cells and to be the likely participants in the histone deacetylation and transrepression that accompanies glucocorticoid mediated reductions in natural killer cell function. Copyright © 2012 Elsevier Inc. All rights reserved.

  14. Probing the effector and suppressive functions of human T cell subsets using antigen-specific engineered T cell receptors.

    Directory of Open Access Journals (Sweden)

    Qi Wan

    Full Text Available Activation of T cells through the engagement of the T cell receptors (TCRs with specific peptide-MHC complexes on antigen presenting cells (APCs is the major determinant for their proliferation, differentiation and display of effector functions. To assess the role of quantity and quality of peptide-MHC presentation in eliciting T cell activation and suppression functions, we genetically engineered human T cells with two TCRs that recognize HLA-A*0201-restricted peptides derived from either HIV or melanoma antigens. The engineered-TCRs are highly functional in both CD8(+ and CD4(+ T cells as assessed by the upregulation of activation markers, induction of cytokine secretion and cytotoxicity. We further demonstrated that engineered-TCRs can also be expressed on naïve human T cells, which are stimulated through APCs presenting specific peptides to induce T cell proliferation and acquire effector functions. Furthermore, regulatory T cells (Tregs ectopically expressing the engineered-TCRs are activated in an antigen-specific fashion and suppress T cell proliferation. In this system, the inhibitory activity of peptide-stimulated Tregs require the presence of dendritic cells (DCs in the culture, either as presenters or as bystander cells, pointing to a critical role for DCs in suppression by Tregs. In conclusion, the engineered-TCR system reported here advances our ability to understand the differentiation pathways of naïve T cells into antigen-specific effector cells and the role of antigen-specific signaling in Treg-mediated immune suppression.

  15. Suppression of Natural Killer Cell Activity by FG 7142, a Benzodiazepine Receptor ’Inverse Agonist,’

    Science.gov (United States)

    1989-01-01

    1981). Psychoneuroimmunology . New York: Academic Press. Arora, P. K., Hanna, E. E., Paul. S. M., & Skolnick, P. (1987). Suppression of the immune...Kling, M. A., & Gold, P. W. (1987). Alterations in immunocompetence during stress, bereavement, and depression : Focus on neuroendocrine regulation...Irwin, M., Smith. T., & Gillin. C. (1987). Low natural killer cell activity in major depression . Life Sdi. 41, 2127-2133. Kiecolt-Glaser. J. K.. Garner

  16. New Strategy for Prostate Cancer Prevention Based on Selenium Suppression of Androgen Receptor Signaling

    Science.gov (United States)

    2010-04-01

    5α-reductase inhibitor; prostate cancer; chemoprevention; androgen receptor; FOXO1 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT...influences comparative activity of selenium-enriched garlic and yeast in mammary cancer pre- vention. J Agric Food Chem 2000;48(6):2062–2070. 12. Medina D

  17. Growth suppression by transforming growth factor beta 1 of human small-cell lung cancer cell lines is associated with expression of the type II receptor

    DEFF Research Database (Denmark)

    Nørgaard, P; Damstrup, L; Rygaard, K

    1994-01-01

    was observed in two cell lines expressing only type III receptor and in TGF-beta-r negative cell lines. In two cell lines expressing all three receptor types, growth suppression was accompanied by morphological changes. To evaluate the possible involvement of the retinoblastoma protein (pRb) in mediating...... the growth-suppressive effect of TGF-beta 1, the expression of functional pRb, as characterised by nuclear localisation, was examined by immunocytochemistry. Nuclear association of pRb was only seen in two of the five TGF-beta 1-responsive cell lines. These results indicate that in SCLC pRb is not required...

  18. Role of Anterior Cingulate Cortex in Instrumental Learning: Blockade of Dopamine D1 Receptors Suppresses Overt but Not Covert Learning

    Directory of Open Access Journals (Sweden)

    Mayada Aly-Mahmoud

    2017-05-01

    Full Text Available HIGHLIGHTSBlockade of dopamine D1 receptors in ACC suppressed instrumental learning when overt responding was required.Covert learning through observation was not impaired.After treatment with a dopamine antagonist, instrumental learning recovered but not the rat's pretreatment level of effort tolerance.ACC dopamine is not necessary for acquisition of task-relevant cues during learning, but regulates energy expenditure and effort based decision.Dopamine activity in anterior cingulate cortex (ACC is essential for various aspects of instrumental behavior, including learning and effort based decision making. To dissociate learning from physical effort, we studied both observational (covert learning, and trial-and-error (overt learning. If ACC dopamine activity is required for task acquisition, its blockade should impair both overt and covert learning. If dopamine is not required for task acquisition, but solely for regulating the willingness to expend effort for reward, i.e., effort tolerance, blockade should impair overt learning but spare covert learning. Rats learned to push a lever for food rewards either with or without prior observation of an expert conspecific performing the same task. Before daily testing sessions, the rats received bilateral ACC microinfusions of SCH23390, a dopamine D1 receptor antagonist, or saline-control infusions. We found that dopamine blockade suppressed overt responding selectively, leaving covert task acquisition through observational learning intact. In subsequent testing sessions without dopamine blockade, rats recovered their overt-learning capacity but not their pre-treatment level of effort tolerance. These results suggest that ACC dopamine is not required for the acquisition of conditioned behaviors and that apparent learning impairments could instead reflect a reduced level of willingness to expend effort due to cortical dopamine blockade.

  19. Role of Anterior Cingulate Cortex in Instrumental Learning: Blockade of Dopamine D1 Receptors Suppresses Overt but Not Covert Learning.

    Science.gov (United States)

    Aly-Mahmoud, Mayada; Carlier, Pascal; Salam, Sherine A; Houari Selmani, Mariam; Moftah, Marie Z; Esclapez, Monique; Boussaoud, Driss

    2017-01-01

    HIGHLIGHTS Blockade of dopamine D1 receptors in ACC suppressed instrumental learning when overt responding was required.Covert learning through observation was not impaired.After treatment with a dopamine antagonist, instrumental learning recovered but not the rat's pretreatment level of effort tolerance.ACC dopamine is not necessary for acquisition of task-relevant cues during learning, but regulates energy expenditure and effort based decision. Dopamine activity in anterior cingulate cortex (ACC) is essential for various aspects of instrumental behavior, including learning and effort based decision making. To dissociate learning from physical effort, we studied both observational (covert) learning, and trial-and-error (overt) learning. If ACC dopamine activity is required for task acquisition, its blockade should impair both overt and covert learning. If dopamine is not required for task acquisition, but solely for regulating the willingness to expend effort for reward, i.e., effort tolerance, blockade should impair overt learning but spare covert learning. Rats learned to push a lever for food rewards either with or without prior observation of an expert conspecific performing the same task. Before daily testing sessions, the rats received bilateral ACC microinfusions of SCH23390, a dopamine D1 receptor antagonist, or saline-control infusions. We found that dopamine blockade suppressed overt responding selectively, leaving covert task acquisition through observational learning intact. In subsequent testing sessions without dopamine blockade, rats recovered their overt-learning capacity but not their pre-treatment level of effort tolerance. These results suggest that ACC dopamine is not required for the acquisition of conditioned behaviors and that apparent learning impairments could instead reflect a reduced level of willingness to expend effort due to cortical dopamine blockade.

  20. Initial evidence that GLP-1 receptor blockade fails to suppress postprandial satiety or promote food intake in humans.

    Science.gov (United States)

    Melhorn, Susan J; Tyagi, Vidhi; Smeraglio, Anne; Roth, Christian L; Schur, Ellen A

    2014-11-01

    Glucagon-like peptide 1 (GLP-1) has incretin effects that are well-documented, but the independent role of GLP-1 action in human satiety perception is debated. We hypothesized that blockade of GLP-1 receptors would suppress postprandial satiety and increase voluntary food intake. After an overnight fast, eight normal weight participants (seven men, BMI 19-24.7 kg/m(2), age 19-29 year) were enrolled in a double-blind, placebo-controlled, randomized crossover study of the GLP-1 antagonist Exendin-[9-39] (Ex-9) to determine if the satiating effects of a meal are dependent on GLP-1 signaling in humans. Following a fasting blood draw, iv infusion of Ex-9 (600-750 pmol/kg/min) or saline began. Thirty minutes later, subjects consumed a standardized breakfast followed 90 min later (at the predicted time of maximal endogenous circulating GLP-1) by an ad libitum buffet meal to objectively measure satiety. Infusions ended once the buffet meal was complete. Visual analog scale ratings of hunger and fullness and serial assessments of plasma glucose, insulin, and GLP-1 concentrations were done throughout the experiment. Contrary to the hypothesis, during Ex-9 infusion subjects reported a greater decrease in hunger due to consumption of the breakfast (Ex-9 -62 ± 5; placebo -41 ± 9; P=0.01) than during placebo. There were no differences in ad libitum caloric intake between Ex-9 and placebo. Ex-9 increased glucose, insulin, and endogenous GLP-1, which may have counteracted any effects of Ex-9 infusion to block satiety signaling. Blockade of GLP-1 receptors failed to suppress subjective satiety following a standardized meal or increase voluntary food intake in healthy, normal-weight subjects. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. Suppression of liver receptor homolog-1 by microRNA-451 represses the proliferation of osteosarcoma cells

    Energy Technology Data Exchange (ETDEWEB)

    Li, Zhiyong; Wu, Shuwen; Lv, Shouzheng; Wang, Huili; Wang, Yong; Guo, Qiang, E-mail: qiangguo_gq@163.com

    2015-06-05

    Liver receptor homolog-1 (LRH-1) plays an important role in the onset and progression of many cancer types. However, the role of LRH-1 in osteosarcoma has not been well investigated. In this study, the critical role of LRH-1 in osteosarcoma cells was described. Quantitative polymerase chain reaction and Western blot analysis results revealed that LRH-1 was highly overexpressed in osteosarcoma cells. LRH-1 was knocked down by small interfering RNA (siRNA), and this phenomenon significantly inhibited osteosarcoma cell proliferation. Bioinformatics analysis results showed that LRH-1 contained putative binding sites of microRNA-451 (miR-451); this result was further validated through a dual-luciferase activity reporter assay. miR-451 was overexpressed in osteosarcoma cells through transfection of miR-451 mimics; miR-451 overexpression then significantly inhibited LRH-1 expression and cell proliferation. The loss of LRH-1 by siRNA or miR-451 mimics significantly impaired Wnt/β-catenin activity, leading to G0/G1 cell cycle arrest. Results showed that LRH-1 is implicated in osteosarcoma. Therefore, miR-451-induced suppression of LRH-1 can be a novel therapy to treat osteosarcoma. - Highlights: • LRH-1 was highly overexpressed in osteosarcoma cells. • Knockdown of LRH-1 inhibited osteosarcoma cell proliferation. • miR-451 directly targeted and regulated LRH-1 expression. • Overexpression of miR-451 suppressed Wnt activity.

  2. The hederagenin saponin SMG-1 is a natural FMLP receptor inhibitor that suppresses human neutrophil activation.

    Science.gov (United States)

    Hwang, Tsong-Long; Wang, Chien-Chiao; Kuo, Yao-Haur; Huang, Hui-Chi; Wu, Yang-Chang; Kuo, Liang-Mou; Wu, Yi-Hsiu

    2010-10-15

    The pericarp of Sapindus mukorossi Gaertn is traditionally used as an expectorant in Japan, China, and Taiwan. Activated neutrophils produce high concentrations of the superoxide anion (O(2)(-)) and elastase known to be involved in airway mucus hypersecretion. In the present study, the anti-inflammatory functions of hederagenin 3-O-(3,4-O-di-acetyl-alpha-L-arabinopyranoside)-(1-->3)-alpha-l-rhamnopyranosyl-(1-->2)-alpha-l-arabinopyranoside (SMG-1), a saponin isolated from S. mukorossi, and its underlying mechanisms were investigated in human neutrophils. SMG-1 potently and concentration-dependently inhibited O(2)(*-) generation and elastase release in N-Formyl-Met-Leu-Phe (FMLP)-activated human neutrophils. Furthermore, SMG-1 reduced membrane-associated p47(phox) expression in FMLP-induced intact neutrophils, but did not alter subcellular NADPH oxidase activity in reconstituted systems. SMG-1 attenuated FMLP-induced increase of cytosolic calcium concentration and phosphorylation of p38 MAPK, ERK, JNK, and AKT. However, SMG-1 displayed no effect on cellular cAMP levels and activity of adenylate cyclase and phosphodiesterase. Significantly, receptor-binding analysis showed that SMG-1 inhibited FMLP binding to its receptor in a concentration-dependent manner. In contrast, neither phorbol myristate acetate-induced O(2)(*-) generation and MAPKs activation nor thapsigargin-caused calcium mobilization was altered by SMG-1. Taken together, our results demonstrate that SMG-1 is a natural inhibitor of the FMLP receptor, which may have the potential to be developed into a useful new therapeutic agent for treating neutrophilic inflammatory diseases. Copyright 2010 Elsevier Inc. All rights reserved.

  3. Endogenous activation of adenosine A1 receptors promotes post-ischemic electrocortical burst suppression

    DEFF Research Database (Denmark)

    Ilie, A; Ciocan, D; Constantinescu, A O

    2009-01-01

    . Several lines of evidence suggest that BS reflects an impairment of neocortical connectivity. Here we tested in vivo whether synaptic depression by adenosine A1 receptor (A1R) activation contributes to BS patterns following GCI. Male Wistar rats were subjected to 1, 5 or 10 min of GCI using a "four......-min GCI the effect of DPCPX was only apparent on the initial fast decay of the BS ratio. These data suggest that endogenous adenosine release promotes BS patterns during reperfusion following transient cerebral ischemia. Furthermore, the endogenous A1R activation may be the primary underlying cause...

  4. Activation of Brain Somatostatin Signaling Suppresses CRF Receptor-Mediated Stress Response

    Directory of Open Access Journals (Sweden)

    Andreas Stengel

    2017-04-01

    Full Text Available Corticotropin-releasing factor (CRF is the hallmark brain peptide triggering the response to stress and mediates—in addition to the stimulation of the hypothalamus-pituitary-adrenal (HPA axis—other hormonal, behavioral, autonomic and visceral components. Earlier reports indicate that somatostatin-28 injected intracerebroventricularly counteracts the acute stress-induced ACTH and catecholamine release. Mounting evidence now supports that activation of brain somatostatin signaling exerts a broader anti-stress effect by blunting the endocrine, autonomic, behavioral (with a focus on food intake and visceral gastrointestinal motor responses through the involvement of distinct somatostatin receptor subtypes.

  5. Water extract of Cinnamomum cassia suppresses angiogenesis through inhibition of VEGF receptor 2 phosphorylation.

    Science.gov (United States)

    Kim, Eok-Cheon; Kim, Hye Jin; Kim, Tack-Joong

    2015-01-01

    Angiogenesis, the process of new blood vessel formation, has been a major target for cancer therapy. Antiangiogenic herbal medicines are useful in the treatment of cancer. In this study, we found that a water extract of Cinnamomum cassia (CCWE) was a potent inhibitor of angiogenesis. In cultured human umbilical vein endothelial cells, CCWE suppressed vascular endothelial growth factor (VEGF)-induced proliferation, migration, invasion, tube formation, and intracellular signaling events such as phosphorylation of ERK, p38 and VEGFR2, and activation of matrix metalloproteinase. Furthermore, CCWE inhibited VEGF-induced vessel sprouting of rat aorta ex vivo. These findings might be of particular interest for drug development because VEGF signaling is a potential target for treatment of angiogenesis-associated diseases.

  6. Differential cellular metabolite alterations in HaCaT cells caused by exposure to the aryl hydrocarbon receptor-binding polycyclic aromatic hydrocarbons chrysene, benzo[a]pyrene and dibenzo[a,l]pyrene

    Directory of Open Access Journals (Sweden)

    Sarah Potratz

    2016-01-01

    Full Text Available Polycyclic aromatic hydrocarbons (PAHs are ubiquitous in the human environment. Since they are present in crude oilfractions used for the production of rubber and plastics, consumers may come into direct dermal contacts with these compounds (e.g., via tool handles on a daily basis. Some individual PAHs are identified as genotoxic mutagens thereby prompting particular toxicological and environmental concern. Among this group, benzo[a]pyrene (BAP constitutes a model carcinogen which is also used as reference compound for risk assessment purposes. It acts as a strong agonist of the aryl hydrocarbon receptor (AHR and becomes metabolically activated toward mutagenic and carcinogenic intermediates by cytochrome P450-dependent monooxygenases (CYPs. While BAP has been exhaustively characterized with regard to its toxicological properties, there is much less information available for other PAHs. We treated an AHR-proficient immortal human keratinocyte cell line (i.e., HaCaT with three selected PAHs: BAP, chrysene (CRY and dibenzo[a,l]pyrene (DALP. Compound-mediated alterations of endogenous metabolites were investigated by an LC–MS/MS-based targeted approach. To examine AHR-dependent changes of the measured metabolites, AHR-deficient HaCaT knockdown cells (AHR-KD were used for comparison. Our results reveal that 24 metabolites are sufficient to separate the PAH-exposed cells from untreated controls by application of a multivariate model. Alterations in the metabolomics profiles caused by each PAH show influences on the energy and lipid metabolism of the cells indicating reduced tricarboxylic acid (TCA cycle activity and β-oxidation. Up-regulation of sphingomyelin levels after exposure to BAP and DALP point to pro-apoptotic processes caused by these two potent PAHs. Our results suggest that in vitro metabolomics can serve as tool to develop bioassays for application in hazard assessment.

  7. Activation of spinal glucagon-like peptide-1 receptors specifically suppresses pain hypersensitivity.

    Science.gov (United States)

    Gong, Nian; Xiao, Qi; Zhu, Bin; Zhang, Chang-Yue; Wang, Yan-Chao; Fan, Hui; Ma, Ai-Niu; Wang, Yong-Xiang

    2014-04-09

    This study aims to identify the inhibitory role of the spinal glucagon like peptide-1 receptor (GLP-1R) signaling in pain hypersensitivity and its mechanism of action in rats and mice. First, GLP-1Rs were identified to be specifically expressed on microglial cells in the spinal dorsal horn, and profoundly upregulated after peripheral nerve injury. In addition, intrathecal GLP-1R agonists GLP-1(7-36) and exenatide potently alleviated formalin-, peripheral nerve injury-, bone cancer-, and diabetes-induced hypersensitivity states by 60-90%, without affecting acute nociceptive responses. The antihypersensitive effects of exenatide and GLP-1 were completely prevented by GLP-1R antagonism and GLP-1R gene knockdown. Furthermore, exenatide evoked β-endorphin release from both the spinal cord and cultured microglia. Exenatide antiallodynia was completely prevented by the microglial inhibitor minocycline, β-endorphin antiserum, and opioid receptor antagonist naloxone. Our results illustrate a novel spinal dorsal horn microglial GLP-1R/β-endorphin inhibitory pathway in a variety of pain hypersensitivity states.

  8. A Suppressive Antagonism Evidences Progesterone and Estrogen Receptor Pathway Interaction with Concomitant Regulation of Hand2, Bmp2 and ERK during Early Decidualization.

    Directory of Open Access Journals (Sweden)

    Ana C Mestre-Citrinovitz

    Full Text Available Progesterone receptor and estrogen receptor participate in growth and differentiation of the different rat decidual regions. Steroid hormone receptor antagonists were used to study steroid regulation of decidualization. Here we describe a suppressive interaction between progesterone receptor (onapristone and estrogen receptor (ICI182780 antagonists and their relation to a rescue phenomenon with concomitant regulation of Hand2, Bmp2 and p-ERK1/2 during the early decidualization steps. Phenotypes of decidua development produced by antagonist treatments were characterized by morphology, proliferation, differentiation, angiogenesis and expression of signaling molecules. We found that suppression of progesterone receptor activity by onapristone treatment resulted in resorption of the implantation sites with concomitant decrease in progesterone and estrogen receptors, PCNA, KI67 antigen, DESMIN, CCND3, CX43, Prl8a2, and signaling players such as transcription factor Hand2, Bmp2 mRNAs and p-ERK1/2. Moreover, FGF-2 and Vegfa increased as a consequence of onapristone treatment. Implantation sites from antagonist of estrogen receptor treated rats developed all decidual regions, but showed an anomalous blood vessel formation at the mesometrial part of the decidua. The deleterious effect of onapristone was partially counteracted by the impairment of estrogen receptor activity with rescue of expression levels of hormone steroid receptors, proliferation and differentiation markers, and the induction of a probably compensatory increase in signaling molecules Hand2, Bmp2 and ERK1/2 activation compared to oil treated controls. This novel drug interaction during decidualization could be applied to pathological endometrial cell proliferation processes to improve therapies using steroid hormone receptor targets.

  9. β2-Adrenergic Receptor Activation Suppresses the Rat Phenethylamine Hallucinogen-Induced Head Twitch Response: Hallucinogen-Induced Excitatory Post-synaptic Potentials as a Potential Substrate

    Directory of Open Access Journals (Sweden)

    Gerard J. Marek

    2018-02-01

    Full Text Available 5-Hydroxytryptamine2A (5-HT2A receptors are enriched in layers I and Va of the rat prefrontal cortex and neocortex and their activation increases the frequency of glutamatergic excitatory post-synaptic potentials/currents (EPSP/Cs onto layer V pyramidal cells. A number of other G-protein coupled receptors (GPCRs are also enriched in cortical layers I and Va and either induce (α1-adrenergic and orexin2 or suppress (metabotropic glutamate2 [mGlu2], adenosine A1, μ-opioid both 5-HT-induced EPSCs and head twitches or head shakes induced by the phenethylamine hallucinogen 2,5-dimethoxy-4-iodoamphetamine (DOI. Another neurotransmitter receptor also localized to apparent thalamocortical afferents to layers I and Va of the rat prefrontal cortex and neocortex is the β2-adrenergic receptor. Therefore, we conducted preliminary electrophysiological experiments with rat brain slices examining the effects of epinephrine on electrically-evoked EPSPs following bath application of DOI (3 μM. Epinephrine (0.3–10 μM suppressed the late EPSPs produced by electrical stimulation and DOI. The selective β2-adrenergic receptor antagonist ICI-118,551 (300 nM resulted in a rightward shift of the epinephrine concentration-response relationship. We also tested the selective β2-adrenergic receptor agonist clenbuterol and the antagonist ICI-118,551 on DOI-induced head twitches. Clenbuterol (0.3–3 mg/kg, i.p. suppressed DOI (1.25 mg/kg, i.p.-induced head twitches. This clenbuterol effect appeared to be at least partially reversed by the selective β2-adrenergic receptor antagonist ICI-118,553 (0.01–1 mg/kg, i.p., with significant reversal at doses of 0.1 and 1 mg/kg. Thus, β2-adrenergic receptor activation reverses the effects of phenethylamine hallucinogens in the rat prefrontal cortex. While Gi/Go-coupled GPCRs have previously been shown to suppress both the electrophysiological and behavioral effects of 5-HT2A receptor activation in the mPFC, the present work

  10. Transcriptomic assessment of resistance to effects of an aryl hydrocarbon receptor (AHR) agonist in embryos of Atlantic killifish (Fundulus heteroclitus) from a marine Superfund site.

    Science.gov (United States)

    Oleksiak, Marjorie F; Karchner, Sibel I; Jenny, Matthew J; Franks, Diana G; Welch, David B Mark; Hahn, Mark E

    2011-05-24

    Populations of Atlantic killifish (Fundulus heteroclitus) have evolved resistance to the embryotoxic effects of polychlorinated biphenyls (PCBs) and other halogenated and nonhalogenated aromatic hydrocarbons that act through an aryl hydrocarbon receptor (AHR)-dependent signaling pathway. The resistance is accompanied by reduced sensitivity to induction of cytochrome P450 1A (CYP1A), a widely used biomarker of aromatic hydrocarbon exposure and effect, but whether the reduced sensitivity is specific to CYP1A or reflects a genome-wide reduction in responsiveness to all AHR-mediated changes in gene expression is unknown. We compared gene expression profiles and the response to 3,3',4,4',5-pentachlorobiphenyl (PCB-126) exposure in embryos (5 and 10 dpf) and larvae (15 dpf) from F. heteroclitus populations inhabiting the New Bedford Harbor, Massachusetts (NBH) Superfund site (PCB-resistant) and a reference site, Scorton Creek, Massachusetts (SC; PCB-sensitive). Analysis using a 7,000-gene cDNA array revealed striking differences in responsiveness to PCB-126 between the populations; the differences occur at all three stages examined. There was a sizeable set of PCB-responsive genes in the sensitive SC population, a much smaller set of PCB-responsive genes in NBH fish, and few similarities in PCB-responsive genes between the two populations. Most of the array results were confirmed, and additional PCB-regulated genes identified, by RNA-Seq (deep pyrosequencing). The results suggest that NBH fish possess a gene regulatory defect that is not specific to one target gene such as CYP1A but rather lies in a regulatory pathway that controls the transcriptional response of multiple genes to PCB exposure. The results are consistent with genome-wide disruption of AHR-dependent signaling in NBH fish.

  11. Transcriptomic assessment of resistance to effects of an aryl hydrocarbon receptor (AHR agonist in embryos of Atlantic killifish (Fundulus heteroclitus from a marine Superfund site

    Directory of Open Access Journals (Sweden)

    Franks Diana G

    2011-05-01

    Full Text Available Abstract Background Populations of Atlantic killifish (Fundulus heteroclitus have evolved resistance to the embryotoxic effects of polychlorinated biphenyls (PCBs and other halogenated and nonhalogenated aromatic hydrocarbons that act through an aryl hydrocarbon receptor (AHR-dependent signaling pathway. The resistance is accompanied by reduced sensitivity to induction of cytochrome P450 1A (CYP1A, a widely used biomarker of aromatic hydrocarbon exposure and effect, but whether the reduced sensitivity is specific to CYP1A or reflects a genome-wide reduction in responsiveness to all AHR-mediated changes in gene expression is unknown. We compared gene expression profiles and the response to 3,3',4,4',5-pentachlorobiphenyl (PCB-126 exposure in embryos (5 and 10 dpf and larvae (15 dpf from F. heteroclitus populations inhabiting the New Bedford Harbor, Massachusetts (NBH Superfund site (PCB-resistant and a reference site, Scorton Creek, Massachusetts (SC; PCB-sensitive. Results Analysis using a 7,000-gene cDNA array revealed striking differences in responsiveness to PCB-126 between the populations; the differences occur at all three stages examined. There was a sizeable set of PCB-responsive genes in the sensitive SC population, a much smaller set of PCB-responsive genes in NBH fish, and few similarities in PCB-responsive genes between the two populations. Most of the array results were confirmed, and additional PCB-regulated genes identified, by RNA-Seq (deep pyrosequencing. Conclusions The results suggest that NBH fish possess a gene regulatory defect that is not specific to one target gene such as CYP1A but rather lies in a regulatory pathway that controls the transcriptional response of multiple genes to PCB exposure. The results are consistent with genome-wide disruption of AHR-dependent signaling in NBH fish.

  12. Adenosine A3 Receptor Suppresses Prostate Cancer Metastasis by Inhibiting NADPH Oxidase Activity

    Directory of Open Access Journals (Sweden)

    Sarvesh Jajoo

    2009-11-01

    Full Text Available Prostate cancer is the most commonly diagnosed and second most lethal malignancy in men, due mainly to a lack of effective treatment for the metastatic disease. A number of recent studies have shown that activation of the purine nucleoside receptor, adenosine A3 receptor (A3AR, attenuates proliferation of melanoma, colon, and prostate cancer cells. In the present study, we determined whether activation of the A3AR reduces the ability of prostate cancer cells to migrate in vitro and metastasize in vivo. Using severe combined immunodeficient mice, we show that proliferation and metastasis of AT6.1 rat prostate cancer cells were decreased by the administration of A3AR agonist N6-(3-iodobenzyl adenosine-5′-N-methyluronamide. In vitro studies show that activation of A3AR decreased high basal nicotinamide adenine dinucleotide phosphate (NADPH oxidase activity present in these cells, along with the expression of Rac1 and p47phox subunits of this enzyme. Inhibition of NADPH oxidase activity by the dominant-negative RacN17 or short interfering (siRNA against p47phox reduced both the generation of reactive oxygen species and the invasion of these cells on Matrigel. In addition, we show that membrane association of p47phox and activation of NADPH oxidase is dependent on the activity of the extracellular signal-regulated kinase (ERK1/2 mitogen-activated protein kinase pathway. We also provide evidence that A3AR inhibits ERK1/2 activity in prostate cancer cells through inhibition of adenylyl cyclase and protein kinase A. We conclude that activation of the A3AR in prostate cancer cells reduces protein kinase A-mediated stimulation of ERK1/2, leading to reduced NADPH oxidase activity and cancer cell invasiveness.

  13. GABA(A) receptor alpha4 subunit suppression prevents withdrawal properties of an endogenous steroid.

    Science.gov (United States)

    Smith, S S; Gong, Q H; Hsu, F C; Markowitz, R S; ffrench-Mullen, J M; Li, X

    1998-04-30

    The hormone progesterone is readily converted to 3alpha-OH-5alpha-pregnan-20-one (3alpha,5alpha-THP) in the brains of males and females. In the brain, 3alpha,5alpha-THP acts like a sedative, decreasing anxiety and reducing seizure activity, by enhancing the function of GABA (gamma-aminobutyric acid), the brain's major inhibitory neurotransmitter. Symptoms of premenstrual syndrome (PMS), such as anxiety and seizure susceptibility, are associated with sharp declines in circulating levels of progesterone and, consequently, of levels of 3alpha,5alpha-THP in the brain. Abrupt discontinuation of use of sedatives such as benzodiazepines and ethanol can also produce PMS-like withdrawal symptoms. Here we report a progesterone-withdrawal paradigm, designed to mimic PMS and post-partum syndrome in a rat model. In this model, withdrawal of progesterone leads to increased seizure susceptibility and insensitivity to benzodiazepine sedatives through an effect on gene transcription. Specifically, this effect was due to reduced levels of 3alpha,5alpha-THP which enhance transcription of the gene encoding the alpha4 subunit of the GABA(A) receptor. We also find that increased susceptibility to seizure after progesferone withdrawal is due to a sixfold decrease in the decay time for GABA currents and consequent decreased inhibitory function. Blockade of the alpha4 gene transcript prevents these withdrawal properties. PMS symptoms may therefore be attributable, in part, to alterations in expression of GABA(A) receptor subunits as a result of progesterone withdrawal.

  14. The aryl hydrocarbon receptor-mediated and genotoxic effects of fractionated extract of standard reference diesel exhaust particle material in pulmonary, liver and prostate cells.

    Science.gov (United States)

    Pálková, Lenka; Vondráček, Jan; Trilecová, Lenka; Ciganek, Miroslav; Pěnčíková, Kateřina; Neča, Jiří; Milcová, Alena; Topinka, Jan; Machala, Miroslav

    2015-04-01

    Diesel exhaust particles (DEP) and the associated complex mixtures of organic pollutants, such as polycyclic aromatic hydrocarbons (PAHs), or their derivatives, have been suggested to exert deleterious effects on human health. We used a set of defined cellular models representing liver, lung and prostate tissues, in order to compare non-genotoxic and genotoxic effects of crude and fractionated extract of a standard reference DEP material - SRM 1650b. We focused on the aryl hydrocarbon receptor (AhR)-mediated activity, modulation of cell proliferation, formation of DNA adducts, oxidative DNA damage, and induction of DNA damage responses, including evaluation of apoptosis, and phosphorylation of p53 tumor suppressor and checkpoint kinases (Chk). Both PAHs and the polar aromatic compounds contributed to the AhR-mediated activity of DEP-associated organic pollutants. The principal identified AhR agonists included benzo[k]fluoranthene, indeno[1,2,3-c,d]pyrene, chrysene and several non-priority PAHs, including benzochrysenes and methylated PAHs. In contrast to PAHs, polar compounds contributed more significantly to overall formation of DNA adducts associated with phosphorylation of p53, Chk1 or Chk2, and partly with apoptosis. Therefore, more attention should be paid to identification of DEP-associated polar organic compounds, contributing to the AhR activation and cytotoxic/genotoxic effects of complex airborne mixtures of organic contaminants produced by diesel engines. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. In Vitro Transformation of Chlorinated Parabens by the Liver S9 Fraction: Kinetics, Metabolite Identification, and Aryl Hydrocarbon Receptor Agonist Activity.

    Science.gov (United States)

    Terasaki, Masanori; Wada, Takeshi; Nagashima, Satoshi; Makino, Masakazu; Yasukawa, Hiro

    2016-01-01

    We investigated the kinetics of in vitro transformation of a dichlorinated propyl paraben (2-propyl 3,5-dichloro-4-hydroxybenzoate; Cl2PP) by the rat liver S9 fraction and assessed the aryl hydrocarbon receptor (AhR) agonist activity of the metabolite products identified in HPLC and GC/MS analysis and by metabolite syntheses. The results indicated that the chlorination of Cl2PP reduced its degradation rate by approximately 40-fold. Two hydroxylated metabolite products showed AhR agonist activity of up to 39% of that of the parent Cl2PP when assessed in a yeast (YCM3) reporter gene assay. The determination of the metabolic properties of paraben bioaccumulation presented here provides further information on the value of risk assessments of chlorinated parabens as a means to ensure human health and environmental safety.

  16. Offspring DNA methylation of the aryl-hydrocarbon receptor repressor gene is associated with maternal BMI, gestational age, and birth weight.

    Science.gov (United States)

    Burris, Heather H; Baccarelli, Andrea A; Byun, Hyang-Min; Cantoral, Alejandra; Just, Allan C; Pantic, Ivan; Solano-Gonzalez, Maritsa; Svensson, Katherine; Tamayo y Ortiz, Marcela; Zhao, Yan; Wright, Robert O; Téllez-Rojo, Martha M

    2015-01-01

    Prenatal smoke exposure, maternal obesity, aberrant fetal growth, and preterm birth are all risk factors for offspring metabolic syndrome. Cord blood aryl-hydrocarbon receptor repressor (AHRR) DNA methylation is responsive to maternal smoking during pregnancy. AHRR serves not only to inhibit aryl-hydrocarbon receptor (AHR) transcription, which is involved in mediating xenobiotic metabolism, but it is also involved in cell growth and differentiation. Other than maternal smoking, other predictors of offspring AHRR DNA methylation status remain unknown; we sought to identify them among newborns. We enrolled pregnant women in the PROGRESS birth cohort in Mexico City. Using pyrosequencing, we analyzed DNA methylation of 3 CpG sites within the AHRR gene promoter from the umbilical cord blood of 531 infants. We used generalized estimating equations to account for the correlation of DNA methylation between CpG sites. Multivariable models were used to adjust for maternal age, BMI, education, parity, smoke-exposure, infant sex, gestational age, and birth weight-for-gestational age. AHRR DNA methylation was positively associated with maternal BMI (P = 0.0009) and negatively associated with the length of gestation (P offspring of obese vs. normal weight mothers and 3.1% higher in preterm vs. term infants, representing a third and a half standard deviation differences in methylation, respectively. In conclusion, offspring AHRR DNA methylation was associated with maternal obesity during pregnancy as well as infant gestational age and birth weight-for-gestational age. Further work to discover the health impacts of altered AHRR DNA methylation is warranted.

  17. Menthol Suppresses Nicotinic Acetylcholine Receptor Functioning in Sensory Neurons via Allosteric Modulation

    Science.gov (United States)

    Wilhelm, M.; Swandulla, D.

    2012-01-01

    In this study, we have investigated how the function of native and recombinant nicotinic acetylcholine receptors (nAChRs) is modulated by the monoterpenoid alcohol from peppermint (−) menthol. In trigeminal neurons (TG), we found that nicotine (75 μM)-activated whole-cell currents through nAChRs were reversibly reduced by menthol in a concentration-dependent manner with an IC50 of 111 μM. To analyze the mechanism underlying menthol's action in more detail, we used single channel and whole-cell recordings from recombinant human α4β2 nAChR expressed in HEK tsA201 cells. Here, we found a shortening of channel open time and a prolongation of channel closed time, and an increase in single channel amplitude leading in summary to a reduction in single channel current. Furthermore, menthol did not affect nicotine's EC50 value for currents through recombinant human α4β2 nAChRs but caused a significant reduction in nicotine's efficacy. Taken together, these findings indicate that menthol is a negative allosteric modulator of nAChRs. PMID:22281529

  18. Suppression of estrogen receptor transcriptional activity by connective tissue growth factor.

    Directory of Open Access Journals (Sweden)

    Long Cheng

    Full Text Available Secreted growth factors have been shown to stimulate the transcriptional activity of estrogen receptors (ER that are responsible for many biological processes. However, whether these growth factors physically interact with ER remains unclear. Here, we show for the first time that connective tissue growth factor (CTGF physically and functionally associates with ER. CTGF interacted with ER both in vitro and in vivo. CTGF interacted with ER DNA-binding domain. ER interaction region in CTGF was mapped to the thrombospondin type I repeat, a cell attachment motif. Overexpression of CTGF inhibited ER transcriptional activity as well as the expression of estrogen-responsive genes, including pS2 and cathepsin D. Reduction of endogenous CTGF with CTGF small interfering RNA enhanced ER transcriptional activity. The interaction between CTGF and ER is required for the repression of estrogen-responsive transcription by CTGF. Moreover, CTGF reduced ER protein expression, whereas the CTGF mutant that did not repress ER transcriptional activity also did not alter ER protein levels. The results suggested the transcriptional regulation of estrogen signaling through interaction between CTGF and ER, and thus may provide a novel mechanism by which cross-talk between secreted growth factor and ER signaling pathways occurs.

  19. Chronic treatment with metformin suppresses toll-like receptor 4 signaling and attenuates left ventricular dysfunction following myocardial infarction.

    Science.gov (United States)

    Soraya, Hamid; Clanachan, Alexander S; Rameshrad, Maryam; Maleki-Dizaji, Nasrin; Ghazi-Khansari, Mahmoud; Garjani, Alireza

    2014-08-15

    Acute treatment with metformin has a protective effect in myocardial infarction by suppression of inflammatory responses due to activation of AMP-activated protein kinase (AMPK). In the present study, the effect of chronic pre-treatment with metformin on cardiac dysfunction and toll-like receptor 4 (TLR4) activities following myocardial infarction and their relation with AMPK were assessed. Male Wistar rats were randomly assigned to one of 5 groups (n=6): normal control and groups were injected isoproterenol after chronic pre-treatment with 0, 25, 50, or 100mg/kg of metformin twice daily for 14 days. Isoproterenol (100mg/kg) was injected subcutaneously on the 13th and 14th days to induce acute myocardial infarction. Isoproterenol alone decreased left ventricular systolic pressure and myocardial contractility indexed as LVdp/dtmax and LVdp/dtmin. The left ventricular dysfunction was significantly lower in the groups treated with 25 and 50mg/kg of metformin. Metfromin markedly lowered isoproterenol-induced elevation in the levels of TLR4 mRNA, myeloid differentiation protein 88 (MyD88), tumor necrosis factor-alpha (TNF-α), and interleukin 6 (IL-6) in the heart tissues. Similar changes were also seen in the serum levels of TNF-α and IL-6. However, the lower doses of 25 and 50mg/kg were more effective than 100mg/kg. Phosphorylated AMPKα (p-AMPK) in the myocardium was significantly elevated by 25mg/kg of metformin, slightly by 50mg/kg, but not by 100mg/kg. Chronic pre-treatment with metformin reduces post-myocardial infarction cardiac dysfunction and suppresses inflammatory responses, possibly through inhibition of TLR4 activities. This mechanism can be considered as a target to protect infarcted myocardium. Copyright © 2014 Elsevier B.V. All rights reserved.

  20. Losartan suppresses the kainate-induced changes of angiotensin AT1 receptor expression in a model of comorbid hypertension and epilepsy.

    Science.gov (United States)

    Atanasova, Dimitrinka; Tchekalarova, Jana; Ivanova, Natasha; Nenchovska, Zlatina; Pavlova, Ekaterina; Atanassova, Nina; Lazarov, Nikolai

    2017-12-06

    Experimental and clinical studies have demonstrated that components of renin-angiotensin system are elevated in the hippocampus in epileptogenic conditions. In the present work, we explored the changes in the expression of angiotensin II receptor, type 1 (AT1 receptor) in limbic structures, as well as the effect of the AT1 receptor antagonist losartan in a model of comorbid hypertension and epilepsy. The expression of AT1 receptors was compared between spontaneously hypertensive rats (SHRs) and Wistar rats by using immunohistochemistry in the kainate (KA) model of temporal lobe epilepsy (TLE). The effect of losartan was studied on AT1 receptor expression in epileptic rats that were treated for a period of 4weeks after status epilepticus. The naive and epileptic SHRs were characterized by stronger protein expression of AT1 receptor than normotensive Wistar rats in the CA1, CA3a, CA3b, CA3c field and the hilus of the dentate gyrus of the dorsal hippocampus but fewer cells were immunostained in the piriform cortex. Increased AT1 immunostaining was observed in the basolateral amygdala of epileptic SHRs but not of epileptic Wistar rats. Losartan exerted stronger and structure-dependent suppression of AT1 receptor expression in SHRs compared to Wistar rats. Our results confirm the important role of AT1 receptor in epilepsy and suggest that the AT1receptor antagonists could be used as a therapeutic strategy for treatment of comorbid hypertension and epilepsy. Copyright © 2017. Published by Elsevier Inc.

  1. Soluble vascular endothelial growth factor receptor-3 suppresses lymphangiogenesis and lymphatic metastasis in bladder cancer

    Directory of Open Access Journals (Sweden)

    Kim Wun-Jae

    2011-04-01

    Full Text Available Abstract Background Most bladder cancer patients experience lymphatic metastasis in the course of disease progression, yet the relationship between lymphangiogenesis and lymphatic metastasis is not well known. The aim of this study is to elucidate underlying mechanisms of how expanded lymphatic vessels and tumor microenvironment interacts each other and to find effective therapeutic options to inhibit lymphatic metastasis. Results The orthotopic urinary bladder cancer (OUBC model was generated by intravesical injection of MBT-2 cell lines. We investigated the angiogenesis, lymphangiogenesis, and CD11b+/CD68+ tumor-associated macrophages (TAM by using immunofluorescence staining. OUBC displayed a profound lymphangiogenesis and massive infiltration of TAM in primary tumor and lymphatic metastasis in lymph nodes. TAM flocked near lymphatic vessels and express higher levels of VEGF-C/D than CD11b- cells. Because VEGFR-3 was highly expressed in lymphatic vascular endothelial cells, TAM could assist lymphangiogenesis by paracrine manner in bladder tumor. VEGFR-3 expressing adenovirus was administered to block VEGF-C/D signaling pathway and clodronate liposome was used to deplete TAM. The blockade of VEGF-C/D with soluble VEGF receptor-3 markedly inhibited lymphangiogenesis and lymphatic metastasis in OUBC. In addition, the depletion of TAM with clodronate liposome exerted similar effects on OUBC. Conclusion VEGF-C/D are the main factors of lymphangiogenesis and lymphatic metastasis in bladder cancer. Moreover, TAM plays an important role in these processes by producing VEGF-C/D. The inhibition of lymphangiogenesis could provide another therapeutic target to inhibit lymphatic metastasis and recurrence in patients with invasive bladder cancer.

  2. Genetic suppression of β2-adrenergic receptors ameliorates tau pathology in a mouse model of tauopathies.

    Science.gov (United States)

    Wisely, Elena V; Xiang, Yang K; Oddo, Salvatore

    2014-08-01

    Accumulation of the microtubule-binding protein tau is a key event in several neurodegenerative disorders referred to as tauopathies, which include Alzheimer's disease, frontotemporal lobar degeneration, Pick's disease, progressive supranuclear palsy and corticobasal degeneration. Thus, understanding the molecular pathways leading to tau accumulation will have a major impact across multiple neurodegenerative disorders. To elucidate the pathways involved in tau pathology, we removed the gene encoding the beta-2 adrenergic receptors (β2ARs) from a mouse model overexpressing mutant human tau. Notably, the number of β2ARs is increased in brains of AD patients and epidemiological studies show that the use of beta-blockers decreases the incidence of AD. The mechanisms underlying these observations, however, are not clear. We show that the tau transgenic mice lacking the β2AR gene had a reduced mortality rate compared with the parental tau transgenic mice. Removing the gene encoding the β2ARs from the tau transgenic mice also significantly improved motor deficits. Neuropathologically, the improvement in lifespan and motor function was associated with a reduction in brain tau immunoreactivity and phosphorylation. Mechanistically, we provide compelling evidence that the β2AR-mediated changes in tau were linked to a reduction in the activity of GSK3β and CDK5, two of the major tau kinases. These studies provide a mechanistic link between β2ARs and tau and suggest the molecular basis linking the use of beta-blockers to a reduced incidence of AD. Furthermore, these data suggest that a detailed pharmacological modulation of β2ARs could be exploited to develop better therapeutic strategies for AD and other tauopathies. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  3. Pterostilbene-isothiocyanate conjugate suppresses growth of prostate cancer cells irrespective of androgen receptor status.

    Directory of Open Access Journals (Sweden)

    Kumar Nikhil

    Full Text Available Chemotherapy and anti-hormonal therapies are the most common treatments for non-organ-confined prostate cancer (PCa. However, the effectiveness of these therapies is limited, thus necessitating the development of alternative approaches. The present study focused on analyzing the role of pterostilbene (PTER-isothiocyanate (ITC conjugate--a novel class of hybrid compound synthesized by appending an ITC moiety on PTER backbone--in regulating the functions of androgen receptor (AR, thereby causing apoptosis of PCa cells. The conjugate molecule caused 50% growth inhibition (IC50 at 40 ± 1.12 and 45 ± 1.50 μM in AR positive (LNCaP and negative (PC-3 cells, respectively. The reduced proliferation of PC-3 as well as LNCaP cells by conjugate correlated with accumulation of cells in G2/M phase and induction of caspase dependent apoptosis. Both PI3K/Akt and MAPK/ERK pathways played an important and differential role in conjugate-induced apoptosis of these PCa cells. While the inhibitor of Akt (A6730 or Akt-specific small interference RNA (siRNA greatly sensitized PC-3 cells to conjugate-induced apoptosis, on the contrary, apoptosis was accelerated by inhibition of ERK (by PD98059 or ERK siRNA in case of LNCaP cells, both ultimately culminating in the expression of cleaved caspase-3 protein. Moreover, anti-androgenic activity of the conjugate was mediated by decreased expression of AR and its co-activators (SRC-1, GRIP-1, thus interfering in their interactions with AR. All these data suggests that conjugate-induced inhibition of cell proliferation and induction of apoptosis are partly mediated by the down regulation of AR, Akt, and ERK signaling. These observations provide a rationale for devising novel therapeutic approaches for treating PCa by using conjugate alone or in combination with other therapeutics.

  4. The bronchodilators 8-iso-prostaglandin E2 and prostaglandin E2 induce K+ current suppression via thromboxane A2 receptors in porcine tracheal smooth muscle.

    Science.gov (United States)

    Helli, Peter B; Catalli, Adriana; Janssen, Luke J

    2004-10-06

    We examined relaxations and changes in K(+) current evoked by 8-iso-prostaglandin E(2) and prostaglandin E(2) in porcine tracheal smooth muscle. Both autacoids completely reversed cholinergic tone; blockade of thromboxane A(2) receptors had no effect on relaxations to either compound. 8-iso-prostaglandin E(2) and prostaglandin E(2) suppressed outward K(+) currents while the thromboxane A(2) receptor agonist U46619 (9, 11-dideoxy-9a,11a-methanoepoxy prostaglandin F(2alpha)) had no significant effect. During thromboxane A(2) receptor antagonism, however, 8-iso-prostaglandin E(2) markedly augmented K(+) currents while prostaglandin E(2) no longer suppressed K(+) currents, indicating that the inhibition of K(+) currents by both compounds was thromboxane A(2) receptor-mediated. Furthermore, the observation that K(+) currents were augmented by 8-iso-prostaglandin E(2) but not by prostaglandin E(2) suggests that the salutory effect is not exerted through a prostaglandin E receptor. Additionally, our observations argue against any causal role for K(+) current activation in mediating relaxations evoked by isoprostanes or by prostaglandin E(2). We conclude that 8-iso-prostaglandin E(2) relaxes porcine tracheal smooth muscle independent of K(+) current activity, and that 8-iso-prostaglandin E(2) may also act at a non-thromboxane A(2)/non-prostaglandin E receptor to augment K(+) currents.

  5. Activation of pattern recognition receptors in brown adipocytes induces inflammation and suppresses uncoupling protein 1 expression and mitochondrial respiration.

    Science.gov (United States)

    Bae, Jiyoung; Ricciardi, Carolyn J; Esposito, Debora; Komarnytsky, Slavko; Hu, Pan; Curry, Benjamin J; Brown, Patricia L; Gao, Zhanguo; Biggerstaff, John P; Chen, Jiangang; Zhao, Ling

    2014-05-15

    Pattern recognition receptors (PRR), Toll-like receptors (TLR), and nucleotide-oligomerization domain-containing proteins (NOD) play critical roles in mediating inflammation and modulating functions in white adipocytes in obesity. However, the role of PRR activation in brown adipocytes, which are recently found to be present in adult humans, has not been studied. Here we report that mRNA of TLR4, TLR2, NOD1, and NOD2 is upregulated, paralleled with upregulated mRNA of inflammatory cytokines and chemokines in the brown adipose tissue (BAT) of the obese mice. During brown adipocyte differentiation, mRNA and protein expression of NOD1 and TLR4, but not TLR2 and NOD2, is also increased. Activation of TLR4, TLR2, or NOD1 in brown adipocytes induces activation of NF-κB and MAPK signaling pathways, leading to inflammatory cytokine/chemokine mRNA expression and/or protein secretion. Moreover, activation of TLR4, TLR2, or NOD1 attenuates both basal and isoproterenol-induced uncoupling protein 1 (UCP-1) expression without affecting mitochondrial biogenesis and lipid accumulation in brown adipocytes. Cellular bioenergetics measurements confirm that attenuation of UCP-1 expression by PRR activation is accompanied by suppression of both basal and isoproterenol-stimulated oxygen consumption rates and isoproterenol-induced uncoupled respiration from proton leak; however, maximal respiration and ATP-coupled respiration are not changed. Further, the attenuation of UCP-1 by PRR activation appears to be mediated through downregulation of the UCP-1 promoter activities. Taken together, our results demonstrate the role of selected PRR activation in inducing inflammation and downregulation of UCP-1 expression and mitochondrial respiration in brown adipocytes. Our results uncover novel targets in BAT for obesity treatment and prevention. Copyright © 2014 the American Physiological Society.

  6. Suppression of Idol expression is an additional mechanism underlying statin-induced up-regulation of hepatic LDL receptor expression.

    Science.gov (United States)

    Dong, Bin; Wu, Minhao; Cao, Aiqin; Li, Hai; Liu, Jingwen

    2011-01-01

    Recent studies have identified proprotein convertase subtilisin/kexin type 9 (PCSK9) and Idol as negative regulators of low density lipoprotein receptor (LDLR) protein stability. While the induction of PCSK9 transcription has been recognized as a limitation to the statin cholesterol-lowering efficacy at higher doses, it is unknown whether Idol is involved in the statin-mediated up-regulation of the hepatic LDLR. Here we report that statins exert opposite effects on PCSK9 and Idol gene expression in human hepatoma-derived cell lines and primary hepatocytes isolated from hamsters and rats. While PCSK9 expression was induced, the level of Idol mRNA rapidly declined in statin-treated cells in a dose-dependent manner. This differs from the effect of the liver X receptor ligand, GW3965, which increased the expression of both PCSK9 and Idol. We further show that cellular depletion of Idol by siRNA transfection did not change PCSK9 expression levels in control and statin-treated cells; however, the basal level of LDLR protein increased by 60% in Idol siRNA transfected HepG2 cells. More importantly, the increase in LDLR protein abundance by rosuvastatin and atorvastatin treatment was compromised by Idol siRNA transfection. Collectively, our present findings suggest that the suppression of Idol gene expression in liver cells is an additional mechanism underlying the statin-induced up-regulation of hepatic LDLR expression. This may contribute to the hypocholesterolemic effects of statins observed in clinical settings.

  7. Propranolol Inhibition of β-Adrenergic Receptor Does Not Suppress Pathologic Neovascularization in Oxygen-Induced Retinopathy

    Science.gov (United States)

    Chen, Jing; Joyal, Jean-Sebastian; Hatton, Colman J.; Juan, Aimee M.; Pei, Dorothy T.; Hurst, Christian G.; Xu, Dan; Stahl, Andreas; Hellstrom, Ann; Smith, Lois E. H.

    2012-01-01

    Purpose. Retinopathy of prematurity (ROP) is a leading cause of blindness in children and is, in its most severe form, characterized by uncontrolled growth of vision-threatening pathologic vessels. Propranolol, a nonselective β-adrenergic receptor blocker, was reported to protect against pathologic retinal neovascularization in a mouse model of oxygen-induced retinopathy (OIR). Based on this single animal study using nonstandard evaluation of retinopathy, clinical trials are currently ongoing to evaluate propranolol treatment in stage 2 ROP patients who tend to experience spontaneous disease regression and are at low risk of blindness. Because these ROP patients are vulnerable premature infants who are still in a fragile state of incomplete development, the efficacy of propranolol treatment in retinopathy needs to be evaluated thoroughly in preclinical animal models of retinopathy and potential benefits weighed against potential adverse effects. Methods. Retinopathy was induced by exposing neonatal mice to 75% oxygen from postnatal day (P) 7 to P12. Three routes of propranolol treatment were assessed from P12 to P16: oral gavage, intraperitoneal injection, or subcutaneous injection, with doses varying between 2 and 60 mg/kg/day. At P17, retinal flatmounts were stained with isolectin and quantified with a standard protocol to measure vasoobliteration and pathologic neovascularization. Retinal gene expression was analyzed with qRT-PCR using RNA isolated from retinas of control and propranolol-treated pups. Results. None of the treatment approaches at any dose of propranolol (up to 60 mg/kg/day) were effective in preventing the development of retinopathy in a mouse model of OIR, evaluated using standard techniques. Propranolol treatment also did not change retinal expression of angiogenic factors including vascular endothelial growth factor. Conclusions. Propranolol treatment via three routes and up to 30 times the standard human dose failed to suppress retinopathy

  8. Targeting mesothelin receptors with drug-loaded bacterial nanocells suppresses human mesothelioma tumour growth in mouse xenograft models.

    Directory of Open Access Journals (Sweden)

    Mohamed A Alfaleh

    Full Text Available Human malignant mesothelioma is a chemoresistant tumour that develops from mesothelial cells, commonly associated with asbestos exposure. Malignant mesothelioma incidence rates in European countries are still rising and Australia has one of the highest burdens of malignant mesothelioma on a population basis in the world. Therapy using systemic delivery of free cytotoxic agents is associated with many undesirable side effects due to non-selectivity, and is thus dose-limited which limits its therapeutic potential. Therefore, increasing the selectivity of anti-cancer agents has the potential to dramatically enhance drug efficacy and reduce toxicity. EnGeneIC Dream Vectors (EDV are antibody-targeted nanocells which can be loaded with cytotoxic drugs and delivered to specific cancer cells via bispecific antibodies (BsAbs which target the EDV and a cancer cell-specific receptor, simultaneously. BsAbs were designed to target doxorubicin-loaded EDVs to cancer cells via cell surface mesothelin (MSLN. Flow cytometry was used to investigate cell binding and induction of apoptosis, and confocal microscopy to visualize internalization. Mouse xenograft models were used to assess anti-tumour effects in vivo, followed by immunohistochemistry for ex vivo evaluation of proliferation and necrosis. BsAb-targeted, doxorubicin-loaded EDVs were able to bind to and internalize within mesothelioma cells in vitro via MSLN receptors and induce apoptosis. In mice xenografts, the BsAb-targeted, doxorubicin-loaded EDVs suppressed the tumour growth and also decreased cell proliferation. Thus, the use of MSLN-specific antibodies to deliver encapsulated doxorubicin can provide a novel and alternative modality for treatment of mesothelioma.

  9. Tramadol and its metabolite m1 selectively suppress transient receptor potential ankyrin 1 activity, but not transient receptor potential vanilloid 1 activity.

    Science.gov (United States)

    Miyano, Kanako; Minami, Kouichiro; Yokoyama, Toru; Ohbuchi, Katsuya; Yamaguchi, Takuhiro; Murakami, Satoshi; Shiraishi, Seiji; Yamamoto, Masahiro; Matoba, Motohiro; Uezono, Yasuhito

    2015-04-01

    The transient receptor potential vanilloid 1 (TRPV1) and the transient receptor potential ankyrin 1 (TRPA1), which are expressed in sensory neurons, are polymodal nonselective cation channels that sense noxious stimuli. Recent reports showed that these channels play important roles in inflammatory, neuropathic, or cancer pain, suggesting that they may serve as attractive analgesic pharmacological targets. Tramadol is an effective analgesic that is widely used in clinical practice. Reportedly, tramadol and its metabolite (M1) bind to μ-opioid receptors and/or inhibit reuptake of monoamines in the central nervous system, resulting in the activation of the descending inhibitory system. However, the fundamental mechanisms of tramadol in pain control remain unclear. TRPV1 and TRPA1 may be targets of tramadol; however, they have not been studied extensively. We examined whether and how tramadol and M1 act on human embryonic kidney 293 (HEK293) cells expressing human TRPV1 (hTRPV1) or hTRPA1 by using a Ca imaging assay and whole-cell patch-clamp recording. Tramadol and M1 (0.01-10 μM) alone did not increase in intracellular Ca concentration ([Ca]i) in HEK293 cells expressing hTRPV1 or hTRPA1 compared with capsaicin (a TRPV1 agonist) or the allyl isothiocyanate (AITC, a TRPA1 agonist), respectively. Furthermore, in HEK293 cells expressing hTRPV1, pretreatment with tramadol or M1 for 5 minutes did not change the increase in [Ca]i induced by capsaicin. Conversely, pretreatment with tramadol (0.1-10 μM) and M1 (1-10 μM) significantly suppressed the AITC-induced [Ca]i increases in HEK293 cells expressing hTRPA1. In addition, the patch-clamp study showed that pretreatment with tramadol and M1 (10 μM) decreased the inward currents induced by AITC. These data indicate that tramadol and M1 selectively inhibit the function of hTRPA1, but not that of hTRPV1, and that hTRPA1 may play a role in the analgesic effects of these compounds.

  10. Interleukin-7 receptor blockade suppresses adaptive and innate inflammatory responses in experimental colitis

    Directory of Open Access Journals (Sweden)

    Willis Cynthia R

    2012-10-01

    Full Text Available Abstract Background Interleukin-7 (IL-7 acts primarily on T cells to promote their differentiation, survival, and homeostasis. Under disease conditions, IL-7 mediates inflammation through several mechanisms and cell types. In humans, IL-7 and its receptor (IL-7R are increased in diseases characterized by inflammation such as atherosclerosis, rheumatoid arthritis, psoriasis, multiple sclerosis, and inflammatory bowel disease. In mice, overexpression of IL-7 results in chronic colitis, and T-cell adoptive transfer studies suggest that memory T cells expressing high amounts of IL-7R drive colitis and are maintained and expanded with IL-7. The studies presented here were undertaken to better understand the contribution of IL-7R in inflammatory bowel disease in which colitis was induced with a bacterial trigger rather than with adoptive transfer. Methods We examined the contribution of IL-7R on inflammation and disease development in two models of experimental colitis: Helicobacter bilis (Hb-induced colitis in immune-sufficient Mdr1a−/− mice and in T- and B-cell-deficient Rag2−/− mice. We used pharmacological blockade of IL-7R to understand the mechanisms involved in IL-7R-mediated inflammatory bowel disease by analyzing immune cell profiles, circulating and colon proteins, and colon gene expression. Results Treatment of mice with an anti-IL-7R antibody was effective in reducing colitis in Hb-infected Mdr1a−/− mice by reducing T-cell numbers as well as T-cell function. Down regulation of the innate immune response was also detected in Hb-infected Mdr1a−/− mice treated with an anti-IL-7R antibody. In Rag2−/− mice where colitis was triggered by Hb-infection, treatment with an anti-IL-7R antibody controlled innate inflammatory responses by reducing macrophage and dendritic cell numbers and their activity. Conclusions Results from our studies showed that inhibition of IL-7R successfully ameliorated inflammation and disease development

  11. N-methyl-D-aspartate receptor agonism and antagonism within the amygdaloid central nucleus suppresses pain affect: differential contribution of the ventrolateral periaqueductal gray.

    Science.gov (United States)

    Spuz, Catherine A; Tomaszycki, Michelle L; Borszcz, George S

    2014-12-01

    The amygdala contributes to the generation of pain affect, and the amygdaloid central nucleus (CeA) receives nociceptive input that is mediated by glutamatergic neurotransmission. The present study compared the contribution of N-methyl-d-aspartate (NMDA) receptor agonism and antagonism in the CeA to generation of the affective response of rats to an acute noxious stimulus. Vocalizations that occur following a brief tail shock (vocalization afterdischarges) are a validated rodent model of pain affect and were preferentially suppressed, in a dose-dependent manner, by bilateral injection into the CeA of NMDA (.1, .25, .5, or 1 μg/side) or the NMDA receptor antagonist d-(-)-2-amino-5-phosphopentanoic acid (AP5; 1, 2, or 4 μg/side). Vocalizations that occur during tail shock were suppressed to a lesser degree, whereas spinal motor reflexes (tail flick and hind limb movements) were unaffected by injection of NMDA or AP5 into the CeA. Injection of NMDA, but not AP5, into the CeA increased c-Fos immunoreactivity in the ventrolateral periaqueductal gray, and unilateral injection of the μ-opiate receptor antagonist H-d-Phe-Cys-Tyr-d-Trp-Arg-Thr-Pen-Thr-NH2 (CTAP; .25 μg) into ventrolateral periaqueductal gray prevented the antinociception generated by injection of NMDA into the CeA. These findings demonstrate that although NMDA receptor agonism and antagonism in the CeA produce similar suppression of pain behaviors, they do so via different neurobiologic mechanisms. The amygdala contributes to production of the emotional dimension of pain. NMDA receptor agonism and antagonism within the CeA suppressed rats' emotional response to acute painful stimulation. Understanding the neurobiology underlying emotional responses to pain will provide insights into new treatments for pain and its associated affective disorders. Copyright © 2014 American Pain Society. Published by Elsevier Inc. All rights reserved.

  12. Steviol, an aglycone of steviol glycoside sweeteners, interacts with the pregnane X (PXR) and aryl hydrocarbon (AHR) receptors in detoxification regulation.

    Science.gov (United States)

    Dusek, Jan; Carazo, Alejandro; Trejtnar, Frantisek; Hyrsova, Lucie; Holas, Ondřej; Smutny, Tomas; Micuda, Stanislav; Pavek, Petr

    2017-11-01

    Stevia rebaudiana Bertoni is a herb known for the high content of natural sweeteners in its leaves. Its main secondary metabolite stevioside is used as non-caloric sweetener. No information, however, is available on whether stevioside or steviol interact with drug-metabolizing enzymes and pose the potential risk of food-drug interactions. Similarly, data are lacking on the interactions of steviol and stevioside with key nuclear receptors controlling the expression of the main drug metabolizing enzymes. We studied the interactions of steviol and stevioside with the pregnane X (PXR), vitamin D (VDR), constitutive androstane (CAR), farnesoid X (FXR), glucocorticoid (GR) and aryl hydrocarbon (AHR) receptors, which control expression of genes of xenobiotic metabolism. In addition, the inhibitory activities of steviol and stevioside towards the major cytochrome P450 enzymes CYP3A4, CYP2C9, CYP2D6, CYP1A2 and CYP2B6 were evaluated in vitro. We found that steviol moderately activated the PXR and AHR, resulting in the induction of their target genes including CYP3A4 and CYP1A2 in primary human hepatocytes. A weak inhibition of CYP3A4 and CYP2C9 with steviol was also found. Our results provide mechanistic data indicating that stevioside and stevia sweeteners may have the potential to induce food-drug interactions, a finding that warrants future prospective clinical investigation. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Effects of currently used pesticides and their mixtures on the function of thyroid hormone and aryl hydrocarbon receptor in cell culture

    Energy Technology Data Exchange (ETDEWEB)

    Ghisari, Mandana; Long, Manhai; Tabbo, Agnese; Bonefeld-Jørgensen, Eva Cecilie, E-mail: ebj@mil.au.dk

    2015-05-01

    Evidence suggest that exposure to pesticides can interfere with the endocrine system by multiple mechanisms. The endocrine disrupting potential of currently used pesticides in Denmark was analyzed as single compounds and in an equimolar mixture of 5 selected pesticides. The pesticides were previously analyzed for effects on the function of estrogen and androgen receptors, the aromatase enzyme and steroidogenesis in vitro. In this study, the effect on thyroid hormone (TH) function and aryl hydrocarbon receptor (AhR) transactivity was assessed using GH3 cell proliferation assay (T-screen) and AhR responsive luciferase reporter gene bioassay, respectively. Thirteen pesticides were analyzed as follows: 2-methyl-4-chlorophenoxyacetic acid, terbuthylazine, iodosulfuron-methyl-sodium, mesosulfuron-methyl, metsulfuron-methyl, chlormequat chloride, bitertanol, propiconazole, prothioconazole, mancozeb and its metabolite ethylene thiourea, cypermethrin, tau-fluvalinate, and malathion (currently banned in DK). In the T-screen, prothioconazole, malathion, tau-fluvalinate, cypermethrin, terbuthylazine and mancozeb significantly stimulated and bitertanol and propiconazole slightly reduced the GH3 cell proliferation. In the presence of triiodothyronine (T3), prothioconazole, tau-fluvalinate, propiconazole, cypermethrin and bitertanol significantly antagonized the T3-induced GH3 cell proliferation. Eleven of the tested pesticides agonized the AhR function, and bitertanol and prothioconazole inhibited the basal AhR activity. Bitertanol, propiconazole, prothioconazole and cypermethrin antagonized the TCDD-induced AhR transactivation at the highest tested concentration. The 5-component mixture had inducing effect but the combined effect could not be predicted due to the presence of bitertanol eliciting inhibitory effect. Upon removal of bitertanol from the mixture, the remaining four pesticides acted additively. In conclusion, our data suggest that pesticides currently used in Denmark

  14. Activated factor X signaling via protease-activated receptor 2 suppresses pro-inflammatory cytokine production from LPS-stimulated myeloid cells.

    LENUS (Irish Health Repository)

    Gleeson, Eimear M

    2013-07-19

    Vitamin K-dependent proteases generated in response to vascular injury and infection enable fibrin clot formation, but also trigger distinct immuno-regulatory signaling pathways on myeloid cells. Factor Xa, a protease crucial for blood coagulation, also induces protease-activated receptor-dependent cell signaling. Factor Xa can bind both monocytes and macrophages, but whether factor Xa-dependent signaling stimulates or suppresses myeloid cell cytokine production in response to Toll-like receptor activation is not known. In this study, exposure to factor Xa significantly impaired pro-inflammatory cytokine production from lipopolysaccharide-treated peripheral blood mononuclear cells, THP-1 monocytic cells and murine macrophages. Furthermore, factor Xa inhibited nuclear factor-kappa B activation in THP-1 reporter cells, requiring phosphatidylinositide 3-kinase activity for its anti-inflammatory effect. Active-site blockade, γ-carboxyglutamic acid domain truncation and a peptide mimic of the factor Xa inter-epidermal growth factor-like region prevented factor Xa inhibition of lipopolysaccharide-induced tumour necrosis factor-α release. In addition, factor Xa anti-inflammatory activity was markedly attenuated by the presence of an antagonist of protease-activated receptor 2, but not protease-activated receptor 1. The key role of protease-activated receptor 2 in eliciting factor Xa-dependent anti-inflammatory signaling on macrophages was further underscored by the inability of factor Xa to mediate inhibition of tumour necrosis factor-α and interleukin-6 release from murine bone marrow-derived protease-activated receptor 2-deficient macrophages. We also show for the first time that, in addition to protease-activated receptor 2, factor Xa requires a receptor-associated protein-sensitive low-density lipoprotein receptor to inhibit lipopolysaccharide-induced cytokine production. Collectively, this study supports a novel function for factor Xa as an endogenous, receptor

  15. The novel cannabinoid CB1 receptor neutral antagonist AM4113 suppresses food intake and food-reinforced behavior but does not induce signs of nausea in rats.

    Science.gov (United States)

    Sink, Kelly S; McLaughlin, Peter J; Wood, Jodi Anne T; Brown, Cara; Fan, Pusheng; Vemuri, V Kiran; Peng, Yan; Pang, Yan; Olszewska, Teresa; Olzewska, Teresa; Thakur, Ganesh A; Makriyannis, Alex; Parker, Linda A; Salamone, John D

    2008-03-01

    Drugs that interfere with cannabinoid CB1 transmission suppress various food-motivated behaviors, and it has been suggested that such drugs could be useful as appetite suppressants. Biochemical studies indicate that most of these drugs assessed thus far have been CB1 inverse agonists, and although they have been shown to suppress food intake, they also appear to induce nausea and malaise. The present studies were undertaken to characterize the behavioral effects of AM4113, which is a CB1 neutral antagonist, and to examine whether this drug can reduce food-reinforced behaviors and feeding on diets with varying macronutrient compositions. Biochemical data demonstrated that AM4113 binds to CB1 receptors, but does not show inverse agonist properties (ie no effects on cyclic-AMP production). In tests of spontaneous locomotion and analgesia, AM4113 reversed the effects of the CB1 agonist AM411. AM4113 suppressed food-reinforced operant responding with rats responding on fixed ratio (FR) 1 and 5 schedules of reinforcement in a dose-dependent manner, and also suppressed feeding on high-fat, high-carbohydrate, and lab chow diets. However, in the same dose range that suppressed feeding, AM4113 did not induce conditioned gaping, which is a sign of nausea and food-related malaise in rats. These results suggest that AM4113 may decrease appetite by blocking endogenous cannabinoid tone, and that this drug may be less associated with nausea than CB1 inverse agonists.

  16. Generation of Tg(cyp1a:gfp) Transgenic Zebrafish for Development of a Convenient and Sensitive In Vivo Assay for Aryl Hydrocarbon Receptor Activity.

    Science.gov (United States)

    Xu, Hongyan; Li, Caixia; Li, Yan; Ng, Grace Hwee Boon; Liu, Chunsheng; Zhang, Xiaoyan; Gong, Zhiyuan

    2015-12-01

    Both dioxins/dioxin-like compounds and polycyclic aromatic hydrocarbons (PAHs) are persistent organic pollutants and cause multiple adverse health effects on human and wildlife. Cyp1a is the most commonly used biomarker induced by these pollutants through activation of the aryl hydrocarbon receptor (AhR) pathway. Here we generated Tg(cyp1a:gfp) transgenic zebrafish for establishing a convenient in vivo assay for analysing these xenobiotic compounds. The Tg(cyp1a:gfp) larvae at 4 day post-fertilization were tested with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), and GFP induction was observed mainly in the kidney, liver and gut. Similar GFP expression was also induced strongly by two dioxin-like chemicals, co-planar polychlorinated biphenyl (PCB126) and polychlorinated dibenzo-p-furan (PeCDF) and relatively weakly by two PAHs, 3-methylcholanthrene (3-MC) and benzo[a]pyrene (BAP). The lowest observed effective concentration (LOEC) of TCDD was estimated to be ∼1 pM and the EC50 (effective concentration to induce GFP in 50 % of Tg(cyp1a:gfp) larvae) was ∼10 pM. PCB126 and PeCDF had ∼10× lower potencies in GFP induction than TCDD, while the potencies for 3-MC and BAP were at least 1000× lower. The sensitivity of Tg(cyp1a:gfp) larvae to respond TCDD was also favourable compared to that of ethoxyresorufin-O-deethylase (EROD) assay in both zebrafish larvae and adult livers. As GFP-based assay in transgenic zebrafish can be easily accommodated in multi-well dishes, the Tg(cyp1a:gfp) zebrafish should provide not only a valuable biomonitoring tool for aquatic contaminants but also a potential high-throughput chemical screening platform for identification of new AhR agonists.

  17. Hydrocarbon toxicity: A review.

    Science.gov (United States)

    Tormoehlen, L M; Tekulve, K J; Nañagas, K A

    2014-06-01

    Clinical effects of hydrocarbon exposure have been reported since 1897. These substances are ubiquitous, and their exposures are common. The specific hydrocarbon and route of exposure will determine the clinical effect, and an understanding of this is helpful in the care of the hydrocarbon-exposed patient. To complete a comprehensive review of the literature on hydrocarbon toxicity and summarize the findings. Relevant literature was identified through searches of Medline (PubMed/OVID) and Cochrane Library databases (inclusive of years 1975-2013), as well as from multiple toxicology textbooks. Bibliographies of the identified articles were also reviewed. Search terms included combinations of the following: hydrocarbons, inhalants, encephalopathy, coma, cognitive deficits, inhalant abuse, huffing, sudden sniffing death, toluene, renal tubular acidosis, metabolic acidosis, arrhythmia, dermatitis, and aspiration pneumonitis. All pertinent clinical trials, observational studies, and case reports relevant to hydrocarbon exposure and published in English were reviewed. Chronic, occupational hydrocarbon toxicity was not included. Exposure to hydrocarbons occurs through one of the following routes: inhalation, ingestion with or without aspiration, or dermal exposure. Inhalational abuse is associated with central nervous system depression, metabolic acidosis, and arrhythmia. The exact mechanism of the CNS depression is unknown, but experimental evidence suggests effects on NMDA, dopamine, and GABA receptors. Chronic toluene inhalation causes a non-anion gap metabolic acidosis associated with hypokalemia. Halogenated hydrocarbon abuse can cause a fatal malignant arrhythmia, termed "sudden sniffing death". Individuals who regularly abuse hydrocarbons are more likely to be polysubstance users, exhibit criminal or violent behavior, and develop memory and other cognitive deficits. Heavy, long-term use results in cerebellar dysfunction, encephalopathy, weakness, and dementia

  18. Targeting Androgen Receptor (AR)?IL12A Signal Enhances Efficacy of Sorafenib Plus NK Cells-Immunotherapy to Better Suppress HCC Progression

    OpenAIRE

    Shi, Liang; LIN, HUI; Li, Gonghui; Jin, Ren-An; Xu, Junjie; Sun, Yin; Ma, Wen-Lung; Yeh, Shuyuan; Cai, Xiujun; Chang, Chawnshang

    2016-01-01

    Gender disparity has long been considered as a key to fully understand hepatocellular carcinoma (HCC) development. At the same time, immunotherapy related to interleukin-12 still need more investigation before being applied in clinical settings. The aim of this study is to investigate the influence of androgen receptor (AR) on natural killer (NK) cells related innate immune surveillance in liver cancer, and provide a novel therapeutic approach to suppress HCC via altering IL-12A. By using in ...

  19. Involvement of aryl hydrocarbon receptor signaling in the development of small cell lung cancer induced by HPV E6/E7 oncoproteins

    Directory of Open Access Journals (Sweden)

    Rossini Mara

    2011-01-01

    Full Text Available Abstract Background Lung cancers consist of four major types that and for clinical-pathological reasons are often divided into two broad categories: small cell lung cancer (SCLC and non-small cell lung cancer (NSCLC. All major histological types of lung cancer are associated with smoking, although the association is stronger for SCLC and squamous cell carcinoma than adenocarcinoma. To date, epidemiological studies have identified several environmental, genetic, hormonal and viral factors associated with lung cancer risk. It has been estimated that 15-25% of human cancers may have a viral etiology. The human papillomavirus (HPV is a proven cause of most human cervical cancers, and might have a role in other malignancies including vulva, skin, oesophagus, head and neck cancer. HPV has also been speculated to have a role in the pathogenesis of lung cancer. To validate the hypothesis of HPV involvement in small cell lung cancer pathogenesis we performed a gene expression profile of transgenic mouse model of SCLC induced by HPV-16 E6/E7 oncoproteins. Methods Gene expression profile of SCLC has been performed using Agilent whole mouse genome (4 × 44k representing ~ 41000 genes and mouse transcripts. Samples were obtained from two HPV16-E6/E7 transgenic mouse models and from littermate's normal lung. Data analyses were performed using GeneSpring 10 and the functional classification of deregulated genes was performed using Ingenuity Pathway Analysis (Ingenuity® Systems, http://www.ingenuity.com. Results Analysis of deregulated genes induced by the expression of E6/E7 oncoproteins supports the hypothesis of a linkage between HPV infection and SCLC development. As a matter of fact, comparison of deregulated genes in our system and those in human SCLC showed that many of them are located in the Aryl Hydrocarbon Receptor Signal transduction pathway. Conclusions In this study, the global gene expression of transgenic mouse model of SCLC induced by HPV-16 E

  20. Identification of aryl hydrocarbon receptor binding targets in mouse hepatic tissue treated with 2,3,7,8-tetrachlorodibenzo-p-dioxin

    Energy Technology Data Exchange (ETDEWEB)

    Lo, Raymond; Celius, Trine [Department of Pharmacology and Toxicology, University of Toronto, Toronto, Ontario (Canada); Forgacs, Agnes L. [Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI (United States); Center for Integrative Toxicology, Michigan State University, East Lansing, MI (United States); Dere, Edward [Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI (United States); MacPherson, Laura [Department of Pharmacology and Toxicology, University of Toronto, Toronto, Ontario (Canada); Harper, Patricia [Department of Pharmacology and Toxicology, University of Toronto, Toronto, Ontario (Canada); Research Institute, The Hospital for Sick Children, Toronto, Ontario (Canada); Zacharewski, Timothy [Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI (United States); Center for Integrative Toxicology, Michigan State University, East Lansing, MI (United States); Matthews, Jason, E-mail: jason.matthews@utoronto.ca [Department of Pharmacology and Toxicology, University of Toronto, Toronto, Ontario (Canada)

    2011-11-15

    Genome-wide, promoter-focused ChIP-chip analysis of hepatic aryl hydrocarbon receptor (AHR) binding sites was conducted in 8-week old female C57BL/6 treated with 30 {mu}g/kg/body weight 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) for 2 h and 24 h. These studies identified 1642 and 508 AHR-bound regions at 2 h and 24 h, respectively. A total of 430 AHR-bound regions were common between the two time points, corresponding to 403 unique genes. Comparison with previous AHR ChIP-chip studies in mouse hepatoma cells revealed that only 62 of the putative target genes overlapped with the 2 h AHR-bound regions in vivo. Transcription factor binding site analysis revealed an over-representation of aryl hydrocarbon response elements (AHREs) in AHR-bound regions with 53% (2 h) and 68% (24 h) of them containing at least one AHRE. In addition to AHREs, E2f-Myc activator motifs previously implicated in AHR function, as well as a number of other motifs, including Sp1, nuclear receptor subfamily 2 factor, and early growth response factor motifs were also identified. Expression microarray studies identified 133 unique genes differentially regulated after 4 h treatment with TCDD. Of which, 39 were identified as AHR-bound genes at 2 h. Ingenuity Pathway Analysis on the 39 AHR-bound TCDD responsive genes identified potential perturbation in biological processes such as lipid metabolism, drug metabolism, and endocrine system development as a result of TCDD-mediated AHR activation. Our findings identify direct AHR target genes in vivo, highlight in vitro and in vivo differences in AHR signaling and show that AHR recruitment does not necessarily result in changes in target gene expression. -- Highlights: Black-Right-Pointing-Pointer ChIP-chip analysis of hepatic AHR binding after 2 h and 24 h of TCDD. Black-Right-Pointing-Pointer We identified 1642 and 508 AHR-bound regions at 2 h and 24 h. Black-Right-Pointing-Pointer 430 regions were common to both time points and highly enriched with

  1. Hypoxia perturbs aryl hydrocarbon receptor signaling and CYP1A1 expression induced by PCB 126 in human skin and liver-derived cell lines

    Energy Technology Data Exchange (ETDEWEB)

    Vorrink, Sabine U. [Interdisciplinary Graduate Program in Human Toxicology, The University of Iowa, Iowa City, IA (United States); Department of Radiation Oncology, The University of Iowa, Iowa City, IA (United States); Severson, Paul L. [Department of Pharmacology and Toxicology, The University of Arizona, Tucson, AZ (United States); Kulak, Mikhail V. [Department of Surgery, The University of Iowa, Iowa City, IA (United States); Futscher, Bernard W. [Department of Pharmacology and Toxicology, The University of Arizona, Tucson, AZ (United States); Domann, Frederick E., E-mail: frederick-domann@uiowa.edu [Interdisciplinary Graduate Program in Human Toxicology, The University of Iowa, Iowa City, IA (United States); Department of Radiation Oncology, The University of Iowa, Iowa City, IA (United States); Department of Surgery, The University of Iowa, Iowa City, IA (United States)

    2014-02-01

    The aryl hydrocarbon receptor (AhR) is an important mediator of toxic responses after exposure to xenobiotics including 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and dioxin-like polychlorinated biphenyls (PCBs). Activation of AhR responsive genes requires AhR dimerization with the aryl hydrocarbon receptor nuclear translocator (ARNT), a heterodimeric partner also shared by the hypoxia-inducible factor-1α (HIF-1α) protein. TCDD-stimulated AhR transcriptional activity can be influenced by hypoxia; however, it less well known whether hypoxia interferes with AhR transcriptional transactivation in the context of PCB-mediated AhR activation in human cells. Elucidation of this interaction is important in liver hepatocytes which extensively metabolize ingested PCBs and experience varying degrees of oxygen tension during normal physiologic function. This study was designed to assess the effect of hypoxia on AhR transcriptional responses after exposure to 3,3′,4,4′,5-pentachlorobiphenyl (PCB 126). Exposure to 1% O{sub 2} prior to PCB 126 treatment significantly inhibited CYP1A1 mRNA and protein expression in human HepG2 and HaCaT cells. CYP1A1 transcriptional activation was significantly decreased upon PCB 126 stimulation under conditions of hypoxia. Additionally, hypoxia pre-treatment reduced PCB 126 induced AhR binding to CYP1 target gene promoters. Importantly, ARNT overexpression rescued cells from the inhibitory effect of hypoxia on XRE-luciferase reporter activity. Therefore, the mechanism of interference of the signaling crosstalk between the AhR and hypoxia pathways appears to be at least in part dependent on ARNT availability. Our results show that AhR activation and CYP1A1 expression induced by PCB 126 were significantly inhibited by hypoxia and hypoxia might therefore play an important role in PCB metabolism and toxicity. - Highlights: • Significant crosstalk exists between AhR and HIF-1α signaling. • Hypoxia perturbs PCB 126 induced AhR function and

  2. Interleukin-1 receptor antagonist (IL1RN) is associated with suppression of early carcinogenic events in human oral malignancies.

    Science.gov (United States)

    Shiiba, Masashi; Saito, Kengo; Yamagami, Hitomi; Nakashima, Dai; Higo, Morihiro; Kasamatsu, Atsushi; Sakamoto, Yosuke; Ogawara, Katsunori; Uzawa, Katsuhiro; Takiguchi, Yuichi; Tanzawa, Hideki

    2015-05-01

    Inflammatory abnormalities have been implicated in the pathogenesis of various human diseases, including cancer. Interleukin-1 receptor antagonist (IL1RN) is a potent anti-inflammatory molecule that modulates the biological activity of the proinflammatory cytokine, interleukin-1. The aim of this study was to examine the expression of IL1RN in oral squamous cell carcinomas (OSCCs), and to determine its clinical significance. Expression levels of IL1RN in matched normal and tumor specimens from 39 OSCCs were evaluated using real-time quantitative polymerase chain reaction methods, and immunohistochemical analysis. Protein expression of IL1RN was also examined in 18 oral premalignant lesions (OPLs). Expression of IL1RN mRNA was significantly downregulated in OSCCs compared with normal tissues. Decreased expression of IL1RN protein was also observed in OPLs and OSCCs. The IL1RN expression level was lower in the OPL cases with severe dysplasia compared to those with mild/moderate dysplasia. Significantly downregulated IL1RN expression was observed in all OSCC lesion sites examined when compared with the matched normal tissues. However, the decreased level of IL1RN expression did not correspond with tumor progression. Noteworthy, IL1RN expression was higher in the advanced OSCC cases (T3/T4) compared to early cases (T1/T2). Among OSCC samples, relatively higher IL1RN expression was associated with active tumor development in the OSCCs occurring in the buccal mucosa, oral floor, fauces and gingiva, but not the tongue. These data suggest that IL1RN may exhibit opposing characteristics in oral malignancies depending on the stage of cancer development, suppressing early carcinogenic events, yet promoting tumor development in some lesion sites. Thus, IL1RN could represent a reliable biomarker for the early diagnosis of OSCCs. Furthermore, IL1RN may possess unknown and complex functions in the developed OSCC.

  3. NLRP3 and ASC suppress lupus-like autoimmunity by driving the immunosuppressive effects of TGF-β receptor signalling.

    Science.gov (United States)

    Lech, Maciej; Lorenz, Georg; Kulkarni, Onkar P; Grosser, Marian O O; Stigrot, Nora; Darisipudi, Murthy N; Günthner, Roman; Wintergerst, Maximilian W M; Anz, David; Susanti, Heni Eka; Anders, Hans-Joachim

    2015-12-01

    The NLRP3/ASC inflammasome drives host defence and autoinflammatory disorders by activating caspase-1 to trigger the secretion of mature interleukin (IL)-1β/IL-18, but its potential role in autoimmunity is speculative. We generated and phenotyped Nlrp3-deficient, Asc-deficient, Il-1r-deficient and Il-18-deficient C57BL/6-lpr/lpr mice, the latter being a mild model of spontaneous lupus-like autoimmunity. While lack of IL-1R or IL-18 did not affect the C57BL/6-lpr/lpr phenotype, lack of NLRP3 or ASC triggered massive lymphoproliferation, lung T cell infiltrates and severe proliferative lupus nephritis within 6 months, which were all absent in age-matched C57BL/6-lpr/lpr controls. Lack of NLRP3 or ASC increased dendritic cell and macrophage activation, the expression of numerous proinflammatory mediators, lymphocyte necrosis and the expansion of most T cell and B cell subsets. In contrast, plasma cells and autoantibody production were hardly affected. This unexpected immunosuppressive effect of NLRP3 and ASC may relate to their known role in SMAD2/3 phosphorylation during tumour growth factor (TGF)-β receptor signalling, for example, Nlrp3-deficiency and Asc-deficiency significantly suppressed the expression of numerous TGF-β target genes in C57BL/6-lpr/lpr mice and partially recapitulated the known autoimmune phenotype of Tgf-β1-deficient mice. These data identify a novel non-canonical immunoregulatory function of NLRP3 and ASC in autoimmunity. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  4. Turmeric (Curcuma longa) inhibits inflammatory nuclear factor (NF)-κB and NF-κB-regulated gene products and induces death receptors leading to suppressed proliferation, induced chemosensitization, and suppressed osteoclastogenesis.

    Science.gov (United States)

    Kim, Ji H; Gupta, Subash C; Park, Byoungduck; Yadav, Vivek R; Aggarwal, Bharat B

    2012-03-01

    The incidence of cancer is significantly lower in regions where turmeric is heavily consumed. Whether lower cancer incidence is due to turmeric was investigated by examining its effects on tumor cell proliferation, on pro-inflammatory transcription factors NF-κB and STAT3, and on associated gene products. Cell proliferation and cell cytotoxicity were measured by the MTT method, NF-κB activity by EMSA, protein expression by Western blot analysis, ROS generation by FACS analysis, and osteoclastogenesis by TRAP assay. Turmeric inhibited NF-κB activation and down-regulated NF-κB-regulated gene products linked to survival (Bcl-2, cFLIP, XIAP, and cIAP1), proliferation (cyclin D1 and c-Myc), and metastasis (CXCR4) of cancer cells. The spice suppressed the activation of STAT3, and induced the death receptors (DR)4 and DR5. Turmeric enhanced the production of ROS, and suppressed the growth of tumor cell lines. Furthermore, turmeric sensitized the tumor cells to chemotherapeutic agents capecitabine and taxol. Turmeric was found to be more potent than pure curcumin for cell growth inhibition. Turmeric also inhibited NF-κB activation induced by RANKL that correlated with the suppression of osteoclastogenesis. Our results indicate that turmeric can effectively block the proliferation of tumor cells through the suppression of NF-κB and STAT3 pathways. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Polycyclic’ Aromatic Hydrocarbon Induced Intracellular Signaling and Lymphocyte Apoptosis

    DEFF Research Database (Denmark)

    Schneider, Alexander M.

    The aryl hydrocarbon (dioxin) receptor (AhR) is a transcription factor possessing high affinity to potent environmental pollutants, polycyclic aromatic hydrocarbons (PAH) and related halogenated hydrocarbons (e.g. dioxins). Numerous research attribute toxicity of these compounds to the receptor...

  6. Effects of currently used pesticides and their mixtures on the function of thyroid hormone and aryl hydrocarbon receptor in cell culture.

    Science.gov (United States)

    Ghisari, Mandana; Long, Manhai; Tabbo, Agnese; Bonefeld-Jørgensen, Eva Cecilie

    2015-05-01

    Evidence suggest that exposure to pesticides can interfere with the endocrine system by multiple mechanisms. The endocrine disrupting potential of currently used pesticides in Denmark was analyzed as single compounds and in an equimolar mixture of 5 selected pesticides. The pesticides were previously analyzed for effects on the function of estrogen and androgen receptors, the aromatase enzyme and steroidogenesis in vitro. In this study, the effect on thyroid hormone (TH) function and aryl hydrocarbon receptor (AhR) transactivity was assessed using GH3 cell proliferation assay (T-screen) and AhR responsive luciferase reporter gene bioassay, respectively. Thirteen pesticides were analyzed as follows: 2-methyl-4-chlorophenoxyacetic acid, terbuthylazine, iodosulfuron-methyl-sodium, mesosulfuron-methyl, metsulfuron-methyl, chlormequat chloride, bitertanol, propiconazole, prothioconazole, mancozeb and its metabolite ethylene thiourea, cypermethrin, tau-fluvalinate, and malathion (currently banned in DK). In the T-screen, prothioconazole, malathion, tau-fluvalinate, cypermethrin, terbuthylazine and mancozeb significantly stimulated and bitertanol and propiconazole slightly reduced the GH3 cell proliferation. In the presence of triiodothyronine (T3), prothioconazole, tau-fluvalinate, propiconazole, cypermethrin and bitertanol significantly antagonized the T3-induced GH3 cell proliferation. Eleven of the tested pesticides agonized the AhR function, and bitertanol and prothioconazole inhibited the basal AhR activity. Bitertanol, propiconazole, prothioconazole and cypermethrin antagonized the TCDD-induced AhR transactivation at the highest tested concentration. The 5-component mixture had inducing effect but the combined effect could not be predicted due to the presence of bitertanol eliciting inhibitory effect. Upon removal of bitertanol from the mixture, the remaining four pesticides acted additively. In conclusion, our data suggest that pesticides currently used in Denmark

  7. Aryl hydrocarbon receptor knockout rats are insensitive to the pathological effects of repeated oral exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin.

    Science.gov (United States)

    Harrill, Joshua A; Layko, Debra; Nyska, Abraham; Hukkanen, Renee R; Manno, Rosa Anna; Grassetti, Andrea; Lawson, Marie; Martin, Greg; Budinsky, Robert A; Rowlands, J Craig; Thomas, Russell S

    2016-06-01

    Sustained activation of the aryl hydrocarbon receptor (AHR) is believed to be the initial key event in AHR receptor-mediated tumorigenesis in the rat liver. The role of AHR in mediating pathological changes in the liver prior to tumor formation was investigated in a 4-week, repeated-dose study using adult female wild-type (WT) and AHR knockout (AHR-KO) rats treated with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Beginning at 8 weeks of age, AHR-KO and WT rats were dosed by oral gavage with varying concentrations of TCDD (0, 3, 22, 100, 300 and 1000 ng kg(-1)  day(-1) ). Lung, liver and thymus histopathology, hematology, serum chemistry and the distribution of TCDD in liver and adipose tissue were examined. Treatment-related increases in the severity of liver and thymus pathology were observed in WT, but not AHR-KO rats. In the liver, these included hepatocellular hypertrophy, bile duct hyperplasia, multinucleated hepatocytes and inflammatory cell foci. A loss of cellularity in the thymic cortex and thymic atrophy was observed. Treatment-related changes in serum chemistry parameters were also observed in WT, but not AHR-KO rats. Finally, dose-dependent accumulation of TCDD was observed primarily in the liver of WT rats and primarily in the adipose tissue of AHR-KO rats. The results suggest that AHR activation is the initial key event underlying the progression of histological effects leading to liver tumorigenesis following TCDD treatment. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.

  8. Source apportionment of ambient non-methane hydrocarbons in Hong Kong: application of a principal component analysis/absolute principal component scores (PCA/APCS) receptor model.

    Science.gov (United States)

    Guo, H; Wang, T; Louie, P K K

    2004-06-01

    Receptor-oriented source apportionment models are often used to identify sources of ambient air pollutants and to estimate source contributions to air pollutant concentrations. In this study, a PCA/APCS model was applied to the data on non-methane hydrocarbons (NMHCs) measured from January to December 2001 at two sampling sites: Tsuen Wan (TW) and Central & Western (CW) Toxic Air Pollutants Monitoring Stations in Hong Kong. This multivariate method enables the identification of major air pollution sources along with the quantitative apportionment of each source to pollutant species. The PCA analysis identified four major pollution sources at TW site and five major sources at CW site. The extracted pollution sources included vehicular internal engine combustion with unburned fuel emissions, use of solvent particularly paints, liquefied petroleum gas (LPG) or natural gas leakage, and industrial, commercial and domestic sources such as solvents, decoration, fuel combustion, chemical factories and power plants. The results of APCS receptor model indicated that 39% and 48% of the total NMHCs mass concentrations measured at CW and TW were originated from vehicle emissions, respectively. 32% and 36.4% of the total NMHCs were emitted from the use of solvent and 11% and 19.4% were apportioned to the LPG or natural gas leakage, respectively. 5.2% and 9% of the total NMHCs mass concentrations were attributed to other industrial, commercial and domestic sources, respectively. It was also found that vehicle emissions and LPG or natural gas leakage were the main sources of C(3)-C(5) alkanes and C(3)-C(5) alkenes while aromatics were predominantly released from paints. Comparison of source contributions to ambient NMHCs at the two sites indicated that the contribution of LPG or natural gas at CW site was almost twice that at TW site. High correlation coefficients (R(2) > 0.8) between the measured and predicted values suggested that the PCA/APCS model was applicable for estimation

  9. Araguspongine C Induces Autophagic Death in Breast Cancer Cells through Suppression of c-Met and HER2 Receptor Tyrosine Kinase Signaling

    Directory of Open Access Journals (Sweden)

    Mohamed R. Akl

    2015-01-01

    Full Text Available Receptor tyrosine kinases are key regulators of cellular growth and proliferation. Dysregulations of receptor tyrosine kinases in cancer cells may promote tumorigenesis by multiple mechanisms including enhanced cell survival and inhibition of cell death. Araguspongines represent a group of macrocyclic oxaquinolizidine alkaloids isolated from the marine sponge Xestospongia species. This study evaluated the anticancer activity of the known oxaquinolizidine alkaloids araguspongines A, C, K and L, and xestospongin B against breast cancer cells. Araguspongine C inhibited the proliferation of multiple breast cancer cell lines in vitro in a dose-dependent manner. Interestingly, araguspongine C-induced autophagic cell death in HER2-overexpressing BT-474 breast cancer cells was characterized by vacuole formation and upregulation of autophagy markers including LC3A/B, Atg3, Atg7, and Atg16L. Araguspongine C-induced autophagy was associated with suppression of c-Met and HER2 receptor tyrosine kinase activation. Further in-silico docking studies and cell-free Z-LYTE assays indicated the potential of direct interaction between araguspongine C and the receptor tyrosine kinases c-Met and HER2 at their kinase domains. Remarkably, araguspongine C treatment resulted in the suppression of PI3K/Akt/mTOR signaling cascade in breast cancer cells undergoing autophagy. Induction of autophagic death in BT-474 cells was also associated with decreased levels of inositol 1,4,5-trisphosphate receptor upon treatment with effective concentration of araguspongine C. In conclusion, results of this study are the first to reveal the potential of araguspongine C as an inhibitor to receptor tyrosine kinases resulting in the induction of autophagic cell death in breast cancer cells.

  10. Circadian clock gene aryl hydrocarbon receptor nuclear translocator-like polymorphisms are associated with seasonal affective disorder: An Indian family study.

    Science.gov (United States)

    Rajendran, Bhagya; Janakarajan, Veeramahali Natarajan

    2016-01-01

    Polymorphisms in aryl hydrocarbon receptor nuclear translocator-like (ARNTL) gene, the key component of circadian clock manifests circadian rhythm abnormalities. As seasonal affective disorder (SAD) is associated with disrupted circadian rhythms, the main objective of this study was to screen an Indian family with SAD for ARNTL gene polymorphisms. In this study, 30 members of close-knit family with SAD, 30 age- and sex-matched controls of the same caste with no prior history of psychiatric illness and 30 age- and sex-matched controls belonging to 17 different castes with no prior history of psychiatric illness were genotyped for five different single nucleotide polymorphisms (SNPs) in ARNTL gene by TaqMan allele-specific genotyping assay. Statistical significance was assessed by more powerful quasi-likelihood score test-XM. Most of the family members carried the risk alleles and we observed a highly significant SNP rs2279287 (A/G) in ARNTL gene with an allelic frequency of 0.75. Polymorphisms in ARNTL gene disrupt circadian rhythms causing SAD and genetic predisposition becomes more deleterious in the presence of adverse environment.

  11. Aryl Hydrocarbon Receptor Deficiency in an Exon 3 Deletion Mouse Model Promotes Hematopoietic Stem Cell Proliferation and Impacts Endosteal Niche Cells

    Directory of Open Access Journals (Sweden)

    Zeenath Unnisa

    2016-01-01

    Full Text Available The aryl hydrocarbon receptor (AHR is a ligand-activated transcription factor belonging to the Per-Arnt-Sim (PAS family of proteins. The AHR is involved in hematopoietic stem cell (HSC functions including self-renewal, proliferation, quiescence, and differentiation. We hypothesize that AHR impacts HSC functions by influencing genes that have roles in HSC maintenance and function and that this may occur through regulation of bone marrow (BM niche cells. We examined BM and niche cells harvested from 8-week-old AHR null-allele (KO mice in which exon 3 was deleted in the Ahr gene and compared these data to cells from B6 control mice; young and old (10 months animals were also compared. We report changes in HSCs and peripheral blood cells in mice lacking AHR. Serial transplantation assays revealed a significant increase in long term HSCs. There was a significant increase in mesenchymal stem cells constituting the endosteal BM niche. Gene expression analyses of HSCs revealed an increase in expression of genes involved in proliferation and maintenance of quiescence. Our studies infer that loss of AHR results in increased proliferation and self-renewal of long term HSCs, in part, by influencing the microenvironment in the niche regulating the balance between quiescence and proliferation in HSCs.

  12. The Group 3 Innate Lymphoid Cell Defect in Aryl Hydrocarbon Receptor Deficient Mice Is Associated with T Cell Hyperactivation during Intestinal Infection.

    Directory of Open Access Journals (Sweden)

    Sagie Wagage

    Full Text Available Intestinal infection with the intracellular parasite Toxoplasma gondii results in the translocation of commensal bacteria to peripheral organs and the development of a T cell response specific to the microbiota. In naïve mice, the recently described RORγt+ group 3 innate lymphoid cell (ILC population plays a critical role in promoting intestinal barrier function and limiting responses to gut-resident commensal bacteria. Given this role for group 3 ILCs, studies were performed to evaluate whether these cells might influence the immune response to mucosal infection with T. gondii. Phenotypic characterization of RORγt+ ILCs in T. gondii infected mice revealed that this population decreased following challenge but the population that remained expressed costimulatory molecules and IL-22. One factor that influences the maintenance of RORγt+ ILCs is the aryl hydrocarbon receptor (AHR, a ligand-activated transcription factor, and Ahr-/- mice have a marked defect in the lamina propria group 3 ILC population. When Ahr-/- mice were challenged with T. gondii, they lost more weight than wild type controls. This disease course in Ahr-/- animals was associated with increased T cell responses to Toxoplasma antigen and crude commensal antigen preparations. Together, these data suggest that group 3 ILCs have a role in limiting T cell activation during intestinal infection.

  13. Association of aryl hydrocarbon receptor gene polymorphism with the neurobehavioral function and autonomic nervous system function changes induced by benzo[a]pyrene exposure in coke oven workers.

    Science.gov (United States)

    Zhang, Hongmei; Nie, Jisheng; Li, Xin; Niu, Qiao

    2013-03-01

    To analyze the association of aryl hydrocarbon receptor (AhR) gene polymorphism and the neurotoxicity induced by benzo[a]pyrene (B[a]P) in coke oven workers. Subjects, 214 coke oven workers and 81 controls, were detected for neurobehavioral function and autonomic nervous system (ANS) function. Airborne B[a]P concentration, urinary 1-hydroxypyrene level, and AhR gene polymorphisms were determined and analyzed for their association with B[a]P neurotoxicity. Neurobehavioral function and ANS function were significantly decreased and dependent on B[a]P dose. The AhR GG, GA, and AA genotypes in G1661A fitted the Hardy-Weinberg equation, whereas C1549T and G1708A gene mutants were not detected. Indices indicating neurotoxicity showed no significant difference among individuals with AA, GG, or GA genotype except for the confusion-bewilderment (P > 0.05). The AhR gene polymorphism is not thought to correlate with B[a]P neurotoxicity among coke oven workers.

  14. Nonstructural 5A Protein of Hepatitis C Virus Interferes with Toll-Like Receptor Signaling and Suppresses the Interferon Response in Mouse Liver.

    Directory of Open Access Journals (Sweden)

    Takeya Tsutsumi

    Full Text Available The hepatitis C virus nonstructural protein NS5A is involved in resistance to the host immune response, as well as the viral lifecycle such as replication and maturation. Here, we established transgenic mice expressing NS5A protein in the liver and examined innate immune responses against lipopolysaccharide (LPS in vivo. Intrahepatic gene expression levels of cytokines such as interleukin-6, tumor necrosis factor-α, and interferon-γ were significantly suppressed after LPS injection in the transgenic mouse liver. Induction of the C-C motif chemokine ligand 2, 4, and 5 was also suppressed. Phosphorylation of the signal transducer and activator of transcription 3, which is activated by cytokines, was also reduced, and expression levels of interferon-stimulated genes, 2'-5' oligoadenylate synthase, interferon-inducible double-stranded RNA-activated protein kinase, and myxovirus resistance 1 were similarly suppressed. Since LPS binds to toll-like receptor 4 and stimulates the downstream pathway leading to induction of these genes, we examined the extracellular signal-regulated kinase and IκB-α. The phosphorylation levels of these molecules were reduced in transgenic mouse liver, indicating that the pathway upstream of the molecules was disrupted by NS5A. Further analyses revealed that the interaction between interleukin-1 receptor-associated kinase-1 and tumor necrosis factor receptor associated factor-6 was dispersed in transgenic mice, suggesting that NS5A may interfere with this interaction via myeloid differentiation primary response gene 88, which was shown to interact with NS5A. Since the gut microbiota, a source of LPS, is known to be associated with pathological conditions in liver diseases, our results suggest the involvement of NS5A in the pathogenesis of HCV infected-liver via the suppression of innate immunity.

  15. Persistent Organic Pollutants Modify Gut Microbiota-Host Metabolic Homeostasis in Mice Through Aryl Hydrocarbon Receptor Activation.

    Science.gov (United States)

    Zhang, Limin; Nichols, Robert G; Correll, Jared; Murray, Iain A; Tanaka, Naoki; Smith, Philip B; Hubbard, Troy D; Sebastian, Aswathy; Albert, Istvan; Hatzakis, Emmanuel; Gonzalez, Frank J; Perdew, Gary H; Patterson, Andrew D

    2015-07-01

    Alteration of the gut microbiota through diet and environmental contaminants may disturb physiological homeostasis, leading to various diseases including obesity and type 2 diabetes. Because most exposure to environmentally persistent organic pollutants (POPs) occurs through the diet, the host gastrointestinal tract and commensal gut microbiota are likely to be exposed to POPs. We examined the effect of 2,3,7,8-tetrachlorodibenzofuran (TCDF), a persistent environmental contaminant, on gut microbiota and host metabolism, and we examined correlations between gut microbiota composition and signaling pathways. Six-week-old male wild-type and Ahr-/- mice on the C57BL/6J background were treated with 24 μg/kg TCDF in the diet for 5 days. We used 16S rRNA gene sequencing, 1H nuclear magnetic resonance (NMR) metabolomics, targeted ultra-performance liquid chromatography coupled with triplequadrupole mass spectrometry, and biochemical assays to determine the microbiota compositions and the physiological and metabolic effects of TCDF. Dietary TCDF altered the gut microbiota by shifting the ratio of Firmicutes to Bacteroidetes. TCDF-treated mouse cecal contents were enriched with Butyrivibrio spp. but depleted in Oscillobacter spp. compared with vehicle-treated mice. These changes in the gut microbiota were associated with altered bile acid metabolism. Further, dietary TCDF inhibited the farnesoid X receptor (FXR) signaling pathway, triggered significant inflammation and host metabolic disorders as a result of activation of bacterial fermentation, and altered hepatic lipogenesis, gluconeogenesis, and glycogenolysis in an AHR-dependent manner. These findings provide new insights into the biochemical consequences of TCDF exposure involving the alteration of the gut microbiota, modulation of nuclear receptor signaling, and disruption of host metabolism.

  16. Adeno-Associated Viral Vector-Induced Overexpression of Neuropeptide Y Y2 Receptors in the Hippocampus Suppresses Seizures

    Science.gov (United States)

    Woldbye, David P. D.; Angehagen, Mikael; Gotzsche, Casper R.; Elbrond-Bek, Heidi; Sorensen, Andreas T.; Christiansen, Soren H.; Olesen, Mikkel V.; Nikitidou, Litsa; Hansen, Thomas v. O.; Kanter-Schlifke, Irene; Kokaia, Merab

    2010-01-01

    Gene therapy using recombinant adeno-associated viral vectors overexpressing neuropeptide Y in the hippocampus exerts seizure-suppressant effects in rodent epilepsy models and is currently considered for clinical application in patients with intractable mesial temporal lobe epilepsy. Seizure suppression by neuropeptide Y in the hippocampus is…

  17. Estrogen receptor α and aryl hydrocarbon receptor cross-talk in a transfected hepatoma cell line (HepG2 exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin

    Directory of Open Access Journals (Sweden)

    Manuela Göttel

    2014-01-01

    Full Text Available The prototype dioxin congener 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD is known to exert anti-estrogenic effects via activation of the aryl hydrocarbon receptor (AhR by interfering with the regulation of oestrogen homeostasis and the estrogen receptor α (ERα signalling pathway. The AhR/ER cross-talk is considered to play a crucial role in TCDD- and E2-dependent mechanisms of carcinogenesis, though the concerted mechanism of action in the liver is not yet elucidated. The present study investigated TCDD's impact on the transcriptional cross-talk between AhR and ERα and its modulation by 17β-estradiol (E2 in the human hepatoma cell line HepG2, which is AhR-responsive but ERα-negative. Transient transfection assays with co-transfection of hERα and supplementation of receptor antagonists showed anti-estrogenic action of TCDD via down-regulation of E2-induced ERα signaling. In contrast, enhancement of AhR signaling dependent on ERα was observed providing evidence for increased cytochrome P450 (CYP induction to promote E2 metabolism. However, relative mRNA levels of major E2-metabolizing CYP1A1 and 1B1 and the main E2-detoxifying catechol-O-methyltransferase were not affected by the co-treatments. This study provides new evidence of a TCDD-activated AhR-mediated molecular AhR/ERα cross-talk mechanism at transcriptional level via indirect inhibition of ERα and enhanced transcriptional activity of AhR in HepG2 cells.

  18. Increased CD4(+) T cell co-inhibitory immune receptor CEACAM1 in neonatal sepsis and soluble-CEACAM1 in meningococcal sepsis: a role in sepsis-associated immune suppression?

    NARCIS (Netherlands)

    Flier, M. van der; Sharma, D.B.; Estevao, S.; Emonts, M.; Rook, D.; Hazelzet, J.A.; Goudoever, J.B. van; Hartwig, N.G.

    2013-01-01

    The co-inhibitory immune receptor carcinoembryonic antigen-related cell-adhesion molecule 1 (CEACAM1) and its self-ligand CEACAM1 can suppress T cell function. Suppression of T cell function in sepsis is well documented. Late-onset neonatal sepsis in VLBW-infants was associated with an increased

  19. Increased CD4+ T Cell Co-Inhibitory Immune Receptor CEACAM1 in Neonatal Sepsis and Soluble-CEACAM1 in Meningococcal Sepsis: A Role in Sepsis-Associated Immune Suppression?

    NARCIS (Netherlands)

    M. van der Flier (Michiel); D.B. Sharma (Dyana); S. Estevão (Silvia); M. Emonts (Marieke); D. Rook (Denise); J.A. Hazelzet (Jan); J.B. van Goudoever (Hans); N.G. Hartwig (Nico)

    2013-01-01

    textabstractThe co-inhibitory immune receptor carcinoembryonic antigen-related cell-adhesion molecule 1 (CEACAM1) and its self-ligand CEACAM1 can suppress T cell function. Suppression of T cell function in sepsis is well documented. Late-onset neonatal sepsis in VLBW-infants was associated with an

  20. A Xanthomonas oryzae pv. oryzae effector, XopR, associates with receptor-like cytoplasmic kinases and suppresses PAMP-triggered stomatal closure.

    Science.gov (United States)

    Wang, Shuangfeng; Sun, Jianhang; Fan, Fenggui; Tan, Zhaoyun; Zou, Yanmin; Lu, Dongping

    2016-09-01

    Receptor-like kinases (RLKs) play important roles in plant immunity signaling; thus, many are hijacked by pathogen effectors to promote successful pathogenesis. Xanthomonas oryzae pv. oryzae (Xoo) is the causal agent of rice leaf blight disease. The strain PXO99A has 18 non-TAL (transcription activation-like) effectors; however, their mechanisms of action and host target proteins remain largely unknown. Although the effector XopR from the Xoo strain MAFF311018 was shown to suppress PAMP-triggered immune responses in Arabidopsis, its target has not yet been identified. Here, we show that PXO99A XopR interacts with BIK1 at the plasma membrane. BIK1 is a receptor-like cytoplasmic kinase (RLCK) belonging to the RLK family of proteins and mediates PAMP-triggered stomatal immunity. In turn, BIK1 phosphorylates XopR. Furthermore, XopR suppresses PAMP-triggered stomatal closure in transgenic Arabidopsis expressing XopR. In addition, XopR is able to associate with RLCKs other than BIK1. These results suggest that XopR likely suppresses plant immunity by targeting BIK1 and other RLCKs.

  1. Serotonin 2A receptor mRNA levels in the neonatal dopamine-depleted rat striatum remain upregulated following suppression of serotonin hyperinnervation.

    Science.gov (United States)

    Basura, G J; Walker, P D

    1999-08-05

    Sixty days after bilateral dopamine (DA) depletion (>98%) with 6-hydroxydopamine (6-OHDA) in neonatal rats, serotonin (5-HT) content doubled and 5-HT(2A) receptor mRNA expression rose 54% within the rostral striatum. To determine if striatal 5-HT(2A) receptor mRNA upregulation is dependent on increased 5-HT levels following DA depletion, neonatal rats received dual injections of 6-OHDA and 5,7-dihydroxytryptamine (5,7-DHT) which suppressed 5-HT content by approximately 90%. In these 6-OHDA/5,7-DHT-treated rats, striatal 5-HT(2A) receptor mRNA expression was still elevated (87% above vehicle controls). Comparative analysis of 5-HT(2C) receptor mRNA expression yielded no significant changes in any experimental group. These results demonstrate that upregulated 5-HT(2A) receptor biosynthesis in the DA-depleted rat is not dependent on subsequent 5-HT hyperinnervation. Copyright 1999 Elsevier Science B.V.

  2. Hepatitis C Virus Frameshift/Alternate Reading Frame Protein Suppresses Interferon Responses Mediated by Pattern Recognition Receptor Retinoic-Acid-Inducible Gene-I.

    Directory of Open Access Journals (Sweden)

    Seung Bum Park

    Full Text Available Hepatitis C virus (HCV actively evades host interferon (IFN responses but the mechanisms of how it does so are not completely understood. In this study, we present evidence for an HCV factor that contributes to the suppression of retinoic-acid-inducible gene-I (RIG-I-mediated IFN induction. Expression of frameshift/alternate reading frame protein (F/ARFP from HCV -2/+1 frame in Huh7 hepatoma cells suppressed type I IFN responses stimulated by HCV RNA pathogen-associated molecular pattern (PAMP and poly(IC. The suppression occurred independently of other HCV factors; and activation of interferon stimulated genes, TNFα, IFN-λ1, and IFN-λ2/3 was likewise suppressed by HCV F/ARFP. Point mutations in the full-length HCV sequence (JFH1 genotype 2a strain were made to introduce premature termination codons in the -2/+1 reading frame coding for F/ARFP while preserving the original reading frame, which enhanced IFNα and IFNβ induction by HCV. The potentiation of IFN response by the F/ARFP mutations was diminished in Huh7.5 cells, which already have a defective RIG-I, and by decreasing RIG-I expression in Huh7 cells. Furthermore, adding F/ARFP back via trans-complementation suppressed IFN induction in the F/ARFP mutant. The F/ARFP mutants, on the other hand, were not resistant to exogenous IFNα. Finally, HCV-infected human liver samples showed significant F/ARFP antibody reactivity, compared to HCV-uninfected control livers. Therefore, HCV F/ARFP likely cooperates with other viral factors to suppress type I and III IFN induction occurring through the RIG-I signaling pathway. This study identifies a novel mechanism of pattern recognition receptor modulation by HCV and suggests a biological function of the HCV alternate reading frame in the modulation of host innate immunity.

  3. Perfluorooctanoate suppresses spheroid attachment on endometrial epithelial cells through peroxisome proliferator-activated receptor alpha and down-regulation of Wnt signaling.

    Science.gov (United States)

    Tsang, Hilda; Cheung, Tsz-Yan; Kodithuwakku, Suranga P; Chai, Joyce; Yeung, William S B; Wong, Chris K C; Lee, Kai-Fai

    2013-12-01

    Exposure of animals to perfluorooctanoic acid (PFOA), a surfactant used in emulsion polymerization processes causes early pregnancy loss, delayed growth and development of fetuses. The mechanisms of action are largely unknown. We studied the effect of PFOA on implantation using an in vitro spheroid-endometrial cell co-culture model. PFOA (10-100μM) significantly reduced Jeg-3 spheroid attachment on RL95-2 endometrial cells. PFOA also suppressed β-catenin expression in Jeg-3 cells. The Wnt agonist Wnt3a stimulated β-catenin expression in Jeg-3 cells and reversed the PFOA suppression of the spheroid attachment. The putative PFOA receptors (PPARα, β, γ) present in both cell lines were not affected by PFOA (0.01-100μM). The PPARα antagonist MK886 restored the β-catenin and E-cadherin expression levels in Jeg-3 cells and reversed the suppression of the spheroid attachment caused by PFOA. Taken together, PFOA suppresses spheroid attachment through PPARα and Wnt signaling pathways via down-regulation of β-catenin and E-cadherin expression. Copyright © 2013 Elsevier Inc. All rights reserved.

  4. miR-133a Promotes TRAIL Resistance in Glioblastoma via Suppressing Death Receptor 5 and Activating NF-κB Signaling

    Directory of Open Access Journals (Sweden)

    Shan-shan Wang

    2017-09-01

    Full Text Available Recombinant tumor necrosis factor (TNF-related apoptosis-inducing ligand (TRAIL, as a novel cancer therapeutic, is being tested in phase II and III clinical trials; however, TRAIL resistance remains a big obstacle preventing its clinical application. Considering that TRAIL-induced apoptosis through death receptors DR4 and DR5, their activation may be an alternative pathway to suppress TRAIL resistance. In this study, a negative correlation between DR5 expression and TRAIL resistance was observed, and miR-133a was predicted to be the most promising candidate to suppress DR5 expression. Further investigation demonstrated that miR-133a knockdown dramatically suppressed TRAIL resistance in glioblastoma in vitro and in vivo. An NF-κB family member, phosphorylated IκBα (P-IκBα, was shown to be stimulated by miR-133a, leading to the activation of this signaling. Finally, miR-133a was found to be inversely correlated with DR5 expression in human clinical specimens. In conclusion, our data demonstrate that miR-133a promotes TRAIL resistance in glioblastoma by suppressing DR5 expression and activating NF-κB signaling.

  5. Effects of dexamethasone on purinergic signaling in murine mast cells: Selective suppression of P2X7 receptor expression.

    Science.gov (United States)

    Yoshida, Kazuki; Ito, Masaaki; Hoshino, Yui; Matsuoka, Isao

    2017-12-02

    Mast cells express many different purinergic receptors, including ionotropic P2X4 and P2X7, which recognize the accumulation of extracellular ATP released from activated and/or damaged cells. This results in the stimulation of mast cell functions. In this study, we investigated the effects of dexamethasone (Dex), an anti-inflammatory glucocorticoid widely used for the treatment of allergic disease, on purinergic receptor expression in mouse bone marrow-derived mast cells (BMMCs). Treatment of BMMCs with Dex decreased P2X7 receptor mRNA levels in a time- and concentration-dependent manner without affecting the expression of other purinergic receptor subtypes. Accordingly, fluorescence-activated cell sorting analysis revealed that Dex treatment also decreased P2X7 receptor protein levels. This effect was mimicked by prednisolone, another anti-inflammatory glucocorticoid, and was inhibited by the glucocorticoid receptor antagonist mifepristone. Functionally, treatment of BMMCs with Dex impaired the P2X7-mediated rise in intracellular Ca2+ concentration, degranulation, and ethidium uptake, a response relevant to receptor-pore formation. Finally, oral administration of Dex to C57BL/6 mice in vivo resulted in a significant decrease in P2X7 receptor expression in peritoneal mast cells. These results suggest that reduction of P2X7 receptor expression in mast cells might be one of the anti-allergic mechanisms of Dex. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. Activation of dorsal horn cannabinoid CB2 receptor suppresses the expression of P2Y12 and P2Y13 receptors in neuropathic pain rats.

    Science.gov (United States)

    Niu, Juan; Huang, Dujuan; Zhou, Rui; Yue, MingXia; Xu, Tao; Yang, Junna; He, Li; Tian, Hong; Liu, XiaoHong; Zeng, Junwei

    2017-09-12

    More evidence suggests that dorsal spinal cord microglia is an important site contributing to CB2 receptor-mediated analgesia. The upregulation of P2Y12 and P2Y13 purinoceptors in spinal dorsal horn microglia is involved in the development of pain behavior caused by peripheral nerve injury. However, it is not known whether the expression of P2Y12 and P2Y13 receptors at spinal dorsal horn will be influenced after CB2 receptor activation in neuropathic pain rats. Chronic constriction injury (CCI) and intrathecal ADPbetaS injection were performed in rats to induce neuropathic pain. The paw withdrawal latency (PWL) was used to evaluate thermal hyperalgesia in neuropathic rats. The expression of P2Y12 and P2Y13 receptors, p-p38MAPK, and NF-kappaBp65 was detected with RT-PCR and western blotting analysis. Treatment with AM1241 produces a pronounced inhibition of CCI-induced thermal hyperalgesia and significantly inhibited the increased expression of P2Y12 and P2Y13 receptors at the mRNA and protein levels, which open up the possibility that P2Y12 and P2Y13 receptor expression are downregulated by CB2 receptor agonist AM1241 in CCI rats. Western blot analysis demonstrated that AM1241 reduced the elevated expression of p-p38MAPK and NF-κBp65 in the dorsal spinal cord induced by CCI. After administration with either SB203580 (p38MAPK inhibitor) or PDTC (NF-kappaB inhibitor), the levels of P2Y13 receptor expression in the dorsal spinal cord were lower than those in the CCI group. However, in CCI rats, the increased expression of P2Y12 receptor was prevented by intrathecal administration of PDTC but not by SB203580. In addition, minocycline significantly decreased the increased expression of P2Y12 and P2Y13 receptors. The similar results can be observed in ADPbetaS-treated rats. Intrathecal injection of ADPbataS causes thermal hyperalgesia and increased expression of P2Y12 and P2Y13 receptors in the dorsal spinal cord of naive rats. Moreover, intrathecal injection of AM1241

  7. Distinct roles for aryl hydrocarbon receptor nuclear translocator and ah receptor in estrogen-mediated signaling in human cancer cell lines.

    Directory of Open Access Journals (Sweden)

    Mark P Labrecque

    Full Text Available The activated AHR/ARNT complex (AHRC regulates the expression of target genes upon exposure to environmental contaminants such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD. Importantly, evidence has shown that TCDD represses estrogen receptor (ER target gene activation through the AHRC. Our data indicates that AHR and ARNT act independently from each other at non-dioxin response element sites. Therefore, we sought to determine the specific functions of AHR and ARNT in estrogen-dependent signaling in human MCF7 breast cancer and human ECC-1 endometrial carcinoma cells. Knockdown of AHR with siRNA abrogates dioxin-inducible repression of estrogen-dependent gene transcription. Intriguingly, knockdown of ARNT does not effect TCDD-mediated repression of estrogen-regulated transcription, suggesting that AHR represses ER function independently of ARNT. This theory is supported by the ability of the selective AHR modulator 3',4'-dimethoxy-α-naphthoflavone (DiMNF to repress estrogen-inducible transcription. Furthermore, basal and estrogen-activated transcription of the genes encoding cathepsin-D and pS2 are down-regulated in MCF7 cells but up-regulated in ECC-1 cells in response to loss of ARNT. These responses are mirrored at the protein level with cathepsin-D. Furthermore, knock-down of ARNT led to opposite but corresponding changes in estrogen-stimulated proliferation in both MCF7 and ECC-1 cells. We have obtained experimental evidence demonstrating a dioxin-dependent repressor function for AHR and a dioxin-independent co-activator/co-repressor function for ARNT in estrogen signalling. These results provide us with further insight into the mechanisms of transcription factor crosstalk and putative therapeutic targets in estrogen-positive cancers.

  8. Omeprazole Attenuates Hyperoxic Lung Injury in Mice via Aryl Hydrocarbon Receptor Activation and Is Associated with Increased Expression of Cytochrome P4501A Enzymes

    Science.gov (United States)

    Shivanna, Binoy; Jiang, Weiwu; Wang, Lihua; Couroucli, Xanthi I.

    2011-01-01

    Hyperoxia contributes to lung injury in experimental animals and bronchopulmonary dysplasia (BPD) in preterm infants. Cytochrome P4501A (CYP1A) enzymes, which are regulated by the aryl hydrocarbon receptor (AhR), have been shown to attenuate hyperoxic lung injury in rodents. Omeprazole, a proton pump inhibitor, used in humans to treat gastric acid-related disorders, induces hepatic CYP1A in vitro. However, the mechanism by which omeprazole induces CYP1A and its impact on CYP1A expression in vivo and hyperoxic lung injury are unknown. Therefore, we tested the hypothesis that omeprazole attenuates hyperoxic lung injury in adult wild-type (WT) C57BL/6J mice by an AhR-mediated induction of pulmonary and hepatic CYP1A enzymes. Accordingly, we determined the effects of omeprazole on pulmonary and hepatic CYP1A expression and hyperoxic lung injury in adult WT and AhR dysfunctional (AhRd) mice. We found that omeprazole attenuated lung injury in WT mice. Attenuation of lung injury by omeprazole paralleled enhanced pulmonary CYP1A1 and hepatic CYP1A2 expression in the omeprazole-treated mice. On the other hand, omeprazole failed to enhance pulmonary CYP1A1 and hepatic CYP1A2 expression and protect against hyperoxic lung injury in AhRd mice. In conclusion, our results suggest that omeprazole attenuates hyperoxic lung injury in mice by AhR-mediated mechanisms, and this phenomenon is associated with induction of CYP1A enzymes. These studies have important implications for the prevention and/or treatment of hyperoxia-induced disorders such as BPD in infants and acute respiratory distress syndrome in older children and adults. PMID:21768223

  9. Aminoflavone, a ligand of the Aryl Hydrocarbon Receptor (AhR), inhibits HIF-1α expression in an AhR-independent fashion

    Science.gov (United States)

    Terzuoli, Erika; Puppo, Maura; Rapisarda, Annamaria; Uranchimeg, Badarch; Cao, Liang; Burger, Angelika M.; Ziche, Marina; Melillo, Giovanni

    2010-01-01

    Aminoflavone (AF), the active component of a novel anticancer agent (AFP464) in phase I clinical trials, is a ligand of the aryl hydrocarbon receptor (AhR). AhR dimerizes with HIF-1β/ARNT, which is shared with HIF-1α, a transcription factor critical for the response of cells to oxygen deprivation. To address whether pharmacological activation of the AhR pathway might be a potential mechanism for inhibition of HIF-1, we tested the effects of AF on HIF-1 expression. AF inhibited HIF-1α transcriptional activity and protein accumulation in MCF-7 cells. However, inhibition of HIF-1α by AF was independent from a functional AhR pathway. Indeed, AF inhibited HIF-1α expression in AhR100 cells, in which the AhR pathway is functionally impaired, yet did not induce cytotoxicity, providing evidence that these effects are mediated by distinct signaling pathways. Moreover, AF was inactive in MDA-MB-231 cells, yet inhibited HIF-1α in MDA-MB-231 cells transfected with the SULT1A1 gene. AF inhibited HIF-1α mRNA expression by approximately 50%. Notably, actinomycin-D completely abrogated the ability of AF to down-regulate HIF-1α mRNA, indicating that active transcription was required for the inhibition of HIF-1α expression. Finally, AF inhibited HIF-1α protein accumulation and the expression of HIF-1-target genes in MCF-7 xenografts. These results demonstrate that AF inhibits HIF-1α in an AhR-independent fashion and they unveil additional activities of AF that may be relevant for its further clinical development. PMID:20736373

  10. Diphenylarsinic acid, a chemical warfare-related neurotoxicant, promotes liver carcinogenesis via activation of aryl hydrocarbon receptor signaling and consequent induction of oxidative DAN damage in rats

    Energy Technology Data Exchange (ETDEWEB)

    Wei, Min; Yamada, Takanori; Yamano, Shotaro; Kato, Minoru; Kakehashi, Anna; Fujioka, Masaki; Tago, Yoshiyuki; Kitano, Mistuaki; Wanibuchi, Hideki, E-mail: wani@med.osaka-cu.ac.jp

    2013-11-15

    Diphenylarsinic acid (DPAA), a chemical warfare-related neurotoxic organic arsenical, is present in the groundwater and soil in some regions of Japan due to illegal dumping after World War II. Inorganic arsenic is carcinogenic in humans and its organic arsenic metabolites are carcinogenic in animal studies, raising serious concerns about the carcinogenicity of DPAA. However, the carcinogenic potential of DPAA has not yet been evaluated. In the present study we found that DPAA significantly enhanced the development of diethylnitrosamine-induced preneoplastic lesions in the liver in a medium-term rat liver carcinogenesis assay. Evaluation of the expression of cytochrome P450 (CYP) enzymes in the liver revealed that DPAA induced the expression of CYP1B1, but not any other CYP1, CYP2, or CYP3 enzymes, suggesting that CYP1B1 might be the enzyme responsible for the metabolic activation of DPAA. We also found increased oxidative DNA damage, possibly due to elevated CYP1B1 expression. Induction of CYP1B1 has generally been linked with the activation of AhR, and we found that DPAA activates the aryl hydrocarbon receptor (AhR). Importantly, the promotion effect of DPAA was observed only at a dose that activated the AhR, suggesting that activation of AhR and consequent induction of AhR target genes and oxidative DNA damage plays a vital role in the promotion effects of DPAA. The present study provides, for the first time, evidence regarding the carcinogenicity of DPAA and indicates the necessity of comprehensive evaluation of its carcinogenic potential using long-term carcinogenicity studies. - Highlights: • DPAA, an environmental neurotoxicant, promotes liver carcinogenesis in rats. • DPAA is an activator of AhR signaling pathway. • DPAA promoted oxidative DNA damage in rat livers. • AhR target gene CYP 1B1 might be involved in the metabolism of DPAA.

  11. Differential Expression of the Aryl Hydrocarbon Receptor and Transforming Growth Factor Beta 1 in Chronic Rhinosinusitis with Nasal Polyps with Allergic Rhinitis.

    Science.gov (United States)

    Chen, Lu; Xiao, Ling; Liu, Jie; Shen, Yang; Ke, Xia; Huang, Jiangju; Hu, Guohua; Yang, Yucheng

    2017-11-29

    This study aimed to determine the aryl hydrocarbon receptor (AhR) and transforming growth factor beta 1 (TGF-β1) expression levels in chronic rhinosinusitis (CRS) and their possible correlation with allergic state and tissue remodeling. Patients were enrolled and divided into the following groups: CRS without nasal polyps (NP) without allergic rhinitis (AR) (CRSsNPsAR; n = 20), CRS with NP with AR (CRSwNPwAR; n = 20), CRS with NP without AR (CRSwNPsAR; n = 20), and controls (n = 15). Tissue samples were analyzed by Masson trichrome staining for collagen, while the location and expression of AhR and TGF-β1 were analyzed by immunohistochemistry, quantitative reverse transcription polymerase chain reaction (qRT-PCR), and Western blotting. The collagen amounts as well as AhR and TGF-β1 mRNA and protein expression levels were significantly increased in the CRSsNPsAR group compared with the CRSwNP (CRSwNPsAR and CRSwNPwAR) samples (p < 0.01). However, higher collagen amounts (p < 0.05) and higher TGF-β1 (p < 0.05) but lower AhR expression levels (p < 0.05) were detected in the CRSwNPwAR versus the CRSwNPsAR patients. Both AhR and TGF-β1 expression were positively correlated with the collagen level in CRS samples (p < 0.01). Elevated AhR expression may be involved in the progression of tissue remodeling in CRSsNPsAR similar to TGF-β1 expression. Conversely, lower AhR expression may be involved in allergic reactions in CRSwNPwAR. © 2017 S. Karger AG, Basel.

  12. Epigenetic Determinants of CYP1A1 Induction by the Aryl Hydrocarbon Receptor Agonist 3,3',4,4',5-Pentachlorobiphenyl (PCB 126

    Directory of Open Access Journals (Sweden)

    Sabine U. Vorrink

    2014-08-01

    Full Text Available Many enzymes involved in xenobiotic metabolism, including cytochrome P450 (CYP 1A1, are regulated by the aryl hydrocarbon receptor (AhR. 3,3',4,4',5-Penta chlorobiphenyl (PCB 126 is a potent ligand for AhR and can thus induce the expression of CYP1A1. Interestingly, we observed that human carcinoma cell lines derived from different types of epithelial cells displayed divergent degrees of CYP1A1 induction after exposure to PCB 126. Since epigenetic mechanisms are known to be involved in cell type-specific gene expression, we sought to assess the epigenetic determinants of CYP1A1 induction in these carcinoma cell lines. In contrast to HepG2 hepatocarcinoma cells, HeLa cervical carcinoma cells showed significantly lower levels of CYP1A1 mRNA expression following PCB 126 exposure. Our results show that the two cell lines maintained differences in the chromatin architecture along the CYP1A1 promoter region. Furthermore, treatment with the epigenetic modifiers, trichostatin A (TSA and 5-aza-2'-deoxycytidine (5-Aza-dC, significantly increased the expression of CYP1A1 after PCB 126 treatment in HeLa cells. However, we did not observe apparent differences in methylation levels or specific location of CpG DNA methylation between the two cell lines in the analyzed CYP1A1 promoter region. Taken together, our findings suggest that the differences in CYP1A1 expression between HepG2 and HeLa cells are due to differences in the chromatin architecture of the CYP1A1 promoter and thus establish a role of epigenetic regulation in cell-specific CYP1A1 expression.

  13. Familial Isolated Pituitary Adenomas (FIPA) and the Pituitary Adenoma Predisposition due to Mutations in the Aryl Hydrocarbon Receptor Interacting Protein (AIP) Gene

    Science.gov (United States)

    Aaltonen, Lauri A.; Daly, Adrian F.

    2013-01-01

    Pituitary adenomas are one of the most frequent intracranial tumors and occur with a prevalence of approximately 1:1000 in the developed world. Pituitary adenomas have a serious disease burden, and their management involves neurosurgery, biological therapies, and radiotherapy. Early diagnosis of pituitary tumors while they are smaller may help increase cure rates. Few genetic predictors of pituitary adenoma development exist. Recent years have seen two separate, complimentary advances in inherited pituitary tumor research. The clinical condition of familial isolated pituitary adenomas (FIPA) has been described, which encompasses the familial occurrence of isolated pituitary adenomas outside of the setting of syndromic conditions like multiple endocrine neoplasia type 1 and Carney complex. FIPA families comprise approximately 2% of pituitary adenomas and represent a clinical entity with homogeneous or heterogeneous pituitary adenoma types occurring within the same kindred. The aryl hydrocarbon receptor interacting protein (AIP) gene has been identified as causing a pituitary adenoma predisposition of variable penetrance that accounts for 20% of FIPA families. Germline AIP mutations have been shown to associate with the occurrence of large pituitary adenomas that occur at a young age, predominantly in children/adolescents and young adults. AIP mutations are usually associated with somatotropinomas, but prolactinomas, nonfunctioning pituitary adenomas, Cushing disease, and other infrequent clinical adenoma types can also occur. Gigantism is a particular feature of AIP mutations and occurs in more than one third of affected somatotropinoma patients. Study of pituitary adenoma patients with AIP mutations has demonstrated that these cases raise clinical challenges to successful treatment. Extensive research on the biology of AIP and new advances in mouse Aip knockout models demonstrate multiple pathways by which AIP may contribute to tumorigenesis. This review assesses

  14. Modulation of aryl hydrocarbon receptor target genes in circulating lymphocytes from dairy cows bred in a dioxin-like PCB contaminated area

    Energy Technology Data Exchange (ETDEWEB)

    Girolami, Flavia, E-mail: flavia.girolami@unito.it [Department of Animal Pathology, University of Turin, Via Leonardo da Vinci 44, 10095 Grugliasco (Italy); Spalenza, Veronica, E-mail: veronica.spalenza@unito.it [Department of Animal Production, Epidemiology and Ecology, University of Turin, Via Leonardo da Vinci 44, 10095 Grugliasco (Italy); Carletti, Monica, E-mail: monica.carletti@unito.it [Department of Animal Pathology, University of Turin, Via Leonardo da Vinci 44, 10095 Grugliasco (Italy); Sacchi, Paola, E-mail: paola.sacchi@unito.it [Department of Animal Production, Epidemiology and Ecology, University of Turin, Via Leonardo da Vinci 44, 10095 Grugliasco (Italy); Rasero, Roberto, E-mail: roberto.rasero@unito.it [Department of Animal Production, Epidemiology and Ecology, University of Turin, Via Leonardo da Vinci 44, 10095 Grugliasco (Italy); Nebbia, Carlo, E-mail: carlo.nebbia@unito.it [Department of Animal Pathology, University of Turin, Via Leonardo da Vinci 44, 10095 Grugliasco (Italy)

    2013-04-15

    Animal productions (i.e. fish, eggs, milk and dairy products) represent the major source of exposure to dioxins, furans, and dioxin-like (DL) polychlorobiphenyls for humans. The negative effects of these highly toxic and persistent pollutants are mediated by the activation of the aryl hydrocarbon receptor (AHR) that elicits the transcriptional induction of several genes, including those involved in xenobiotic metabolism. Previously we demonstrated the presence and functioning of the AHR signaling pathway in primary cultures of bovine blood lymphocytes. The aim of the present study was to investigate by real time PCR the expression and the inducibility of selected target genes (i.e. AHR, AHR nuclear translocator (ARNT), AHR repressor, CYP1A1 and CYP1B1) in uncultured cells from dairy cows naturally exposed to DL-compounds. The study was carried out on two groups of animals bred in a highly polluted area and characterized by a different degree of contamination, as assessed by bulk milk TEQ values, and a control group reared in an industry free area. Bovine lymphocytes expressed only AHR, ARNT and CYP1B1 genes to a detectable level; moreover, only CYP1B1 expression appeared to be correlated to TEQ values, being higher in the most contaminated group, and decreasing along with animal decontamination. Finally, lymphocytes from exposed cows displayed a lower inducibility of both CYP1A1 and CYP1B1 after the in vitro treatment with a specific AHR ligand. In conclusion, our results indicate that DL-compound contaminated cows may display significant changes in AHR-target gene expression of circulating lymphocytes. - Highlights: ► The expression of AHR-target genes in blood bovine lymphocytes was evaluated. ► The lymphocyte CYP1B1 expression appears to be related to bulk milk TEQ values. ► Blood lymphocytes from dairy cows might represent a matrix for dioxin biomonitoring.

  15. The Mitochondria-Targeted Antioxidant SkQ1 Downregulates Aryl Hydrocarbon Receptor-Dependent Genes in the Retina of OXYS Rats with AMD-Like Retinopathy

    Directory of Open Access Journals (Sweden)

    M. L. Perepechaeva

    2014-01-01

    Full Text Available The mitochondria-targeted antioxidant SkQ1 is a novel drug thought to retard development of age-related diseases. It has been shown that SkQ1 reduces clinical signs of retinopathy in senescence-accelerated OXYS rats, which are a known animal model of human age-related macular degeneration (AMD. The aim of this work was to test whether SkQ1 affects transcriptional activity of AhR (aryl hydrocarbon receptor and Nrf2 (nuclear factor erythroid 2-related factor 2, which are considered as AMD-associated genes in the retina of OXYS and Wistar rats. Our results showed that only AhR and AhR-dependent genes were sensitive to SkQ1. Dietary supplementation with SkQ1 decreased the AhR mRNA level in both OXYS and Wistar rats. At baseline, the retinal Cyp1a1 mRNA level was lower in OXYS rats. SkQ1 supplementation decreased the Cyp1a1 mRNA level in Wistar rats, but this level remained unchanged in OXYS rats. Baseline Cyp1a2 and Cyp1b1 mRNA expression was stronger in OXYS than in Wistar rats. In the OXYS strain, Cyp1a2 and Cyp1b1 mRNA levels decreased as a result of SkQ1 supplementation. These data suggest that the Cyp1a2 and Cyp1b1 enzymes are involved in the pathogenesis of AMD-like retinopathy of OXYS rats and are possible therapeutic targets of SkQ1.

  16. Mitochondrial-targeted aryl hydrocarbon receptor and the impact of 2,3,7,8-tetrachlorodibenzo-p-dioxin on cellular respiration and the mitochondrial proteome.

    Science.gov (United States)

    Hwang, Hye Jin; Dornbos, Peter; Steidemann, Michelle; Dunivin, Taylor K; Rizzo, Mike; LaPres, John J

    2016-08-01

    The aryl hydrocarbon receptor (AHR) is a ligand-activated transcription factor within the Per-Arnt-Sim (PAS) domain superfamily. Exposure to the most potent AHR ligand, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), is associated with various pathological effects including metabolic syndrome. While research over the last several years has demonstrated a role for oxidative stress and metabolic dysfunction in AHR-dependent TCDD-induced toxicity, the role of the mitochondria in this process has not been fully explored. Our previous research suggested that a portion of the cellular pool of AHR could be found in the mitochondria (mitoAHR). Using a protease protection assay with digitonin extraction, we have now shown that this mitoAHR is localized to the inter-membrane space (IMS) of the organelle. TCDD exposure induced a degradation of mitoAHR similar to that of cytosolic AHR. Furthermore, siRNA-mediated knockdown revealed that translocase of outer-mitochondrial membrane 20 (TOMM20) was involved in the import of AHR into the mitochondria. In addition, TCDD altered cellular respiration in an AHR-dependent manner to maintain respiratory efficiency as measured by oxygen consumption rate (OCR). Stable isotope labeling by amino acids in cell culture (SILAC) identified a battery of proteins within the mitochondrial proteome influenced by TCDD in an AHR-dependent manner. Among these, 17 proteins with fold changes≥2 are associated with various metabolic pathways, suggesting a role of mitochondrial retrograde signaling in TCDD-mediated pathologies. Collectively, these studies suggest that mitoAHR is localized to the IMS and AHR-dependent TCDD-induced toxicity, including metabolic dysfunction, wasting syndrome, and hepatic steatosis, involves mitochondrial dysfunction. Copyright © 2016 Elsevier Inc. All rights reserved.

  17. A rapid and reagent-free bioassay for the detection of dioxin-like compounds and other aryl hydrocarbon receptor (AhR) agonists using autobioluminescent yeast.

    Science.gov (United States)

    Xu, Tingting; Young, Anna; Marr, Enolia; Sayler, Gary; Ripp, Steven; Close, Dan

    2018-02-01

    An autonomously bioluminescent Saccharomyces cerevisiae BLYAhS bioreporter was developed in this study for the simple and rapid detection of dioxin-like compounds (DLCs) and aryl hydrocarbon receptor (AhR) agonists. This recombinant yeast reporter was based on a synthetic bacterial luciferase reporter gene cassette (lux) that can produce the luciferase as well as the enzymes capable of self-synthesizing the requisite substrates for bioluminescent production from endogenous cellular metabolites. As a result, bioluminescent signal production is generated continuously and autonomously without cell lysis or exogenous reagent addition. By linking the expression of the autobioluminescent lux reporter cassette to AhR activation via the use of a dioxin-responsive promoter, the S. cerevisiae BLYAhS bioreporter emitted a bioluminescent signal in response to DLC exposure in a dose-responsive manner. The model dioxin, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), could be detected within 4 h with a half maximal effective concentration (EC50) of ~ 8.1 nM and a lower detection limit of 500 pM. The autobioluminescent response of BLYAhS to other AhR agonists, including 2,3,7,8-tetrachlorodibenzofuran (TCDF), polychlorinated bisphenyl congener 126 (PCB-126) and 169 (PCB-169), 1,2,3,6,7,8-hexachlorodibenzo-p-dioxin (HxCDD), 1,2,3,4,6,7,8-heptachlorodibenzo-p-dioxin (HpCDD), benzo[a]pyrene (BaP), and β-naphthoflavone (bNF), were also characterized in this study. The non-destructive and reagent-free nature of the BLYAhS reporter assay facilitated near-continuous, automated signal acquisition without additional hands-on effort and cost, providing a simple and cost-effective method for rapid DLC detection.

  18. Loss of aryl hydrocarbon receptor promotes gene changes associated with premature hematopoietic stem cell exhaustion and development of a myeloproliferative disorder in aging mice.

    Science.gov (United States)

    Singh, Kameshwar P; Bennett, John A; Casado, Fanny L; Walrath, Jason L; Welle, Stephen L; Gasiewicz, Thomas A

    2014-01-15

    Loss of immune function and increased hematopoietic disease are among the most clinically significant consequences of aging. Hematopoietic stem cells (HSCs) from mice lacking aryl hydrocarbon receptor (AhR) have high rates of cell division. Studies were designed to test the hypothesis that aging AhR-null allele (AhR-KO) mice develop premature HSC exhaustion, and changes leading to hematological disease. Compared to wild-type, aging AhR-KO mice showed a decreased survival rate, splenomegaly, increased circulating white blood cells, hematopoietic cell accumulation in tissues, and anemia. Analysis of bone marrow indicated increased numbers of stem/progenitor and lineage-committed cells, but decreased erythroid progenitors. There was also decreased self-renewal capacity of HSCs determined by competitive repopulation and serial transplantation. HSCs also showed increased levels of reactive oxygen species (ROS), Ki-67, and γ-H2A.X, but decreased p16(Ink4a). Splenic cells from aging KO mice had abnormal expression of genes, including Gata-1, Sh2d3c, Gfi-1, p21, and c-myc, involved in trafficking and associated with leukemia. HSCs from AhR-KO mice had gene changes related to HSC maintenance and consistent with phenotype observed. The most prominent gene changes (overexpression of Srpk2, Creb1, Hes1, mtor, pdp1) have been associated with HSC hyperproliferation, leukemia, and accelerated aging. Pathway analyses also indicated an enrichment of genes associated with oxidative stress, acute myelogenous leukemia, aging, and heat shock response, and the β-catenin/Wnt pathways. These data indicate that loss of AhR and associated changes in multiple signaling pathways promote premature HSC exhaustion and development of a myeloproliferative disorder. They also implicate a critical role of the AhR in the regulation of HSCs.

  19. Protease-activated receptor 2 suppresses lymphangiogenesis and subsequent lymph node metastasis in a murine pancreatic cancer model

    NARCIS (Netherlands)

    Shi, Kun; Queiroz, Karla C. S.; Roelofs, Joris J. T. H.; van Noesel, Carel J. M.; Richel, Dirk J.; Spek, C. Arnold

    2014-01-01

    Protease-activated receptor-2 (PAR-2) is a G protein-coupled receptor that functions as a cell-surface sensor for coagulation factors and other proteases associated with the tumour microenvironment. Pancreatic cancer cells express high levels of PAR-2 and activation of PAR-2 may induce their

  20. Toll-Like Receptor 7 Agonist GS-9620 Induces HIV Expression and HIV-Specific Immunity in Cells from HIV-Infected Individuals on Suppressive Antiretroviral Therapy.

    Science.gov (United States)

    Tsai, Angela; Irrinki, Alivelu; Kaur, Jasmine; Cihlar, Tomas; Kukolj, George; Sloan, Derek D; Murry, Jeffrey P

    2017-04-15

    Antiretroviral therapy can suppress HIV replication to undetectable levels but does not eliminate latent HIV, thus necessitating lifelong therapy. Recent efforts to target this persistent reservoir have focused on inducing the expression of latent HIV so that infected cells may be recognized and eliminated by the immune system. Toll-like receptor (TLR) activation stimulates antiviral immunity and has been shown to induce HIV from latently infected cells. Activation of TLR7 leads to the production of several stimulatory cytokines, including type I interferons (IFNs). In this study, we show that the selective TLR7 agonist GS-9620 induced HIV in peripheral blood mononuclear cells (PBMCs) from HIV-infected individuals on suppressive antiretroviral therapy. GS-9620 increased extracellular HIV RNA 1.5- to 2-fold through a mechanism that required type I IFN signaling. GS-9620 also activated HIV-specific T cells and enhanced antibody-mediated clearance of HIV-infected cells. Activation by GS-9620 in combination with HIV peptide stimulation increased CD8 T cell degranulation, production of intracellular cytokines, and cytolytic activity. T cell activation was again dependent on type I IFNs produced by plasmacytoid dendritic cells. GS-9620 induced phagocytic cell maturation and improved effector-mediated killing of HIV-infected CD4 T cells by the HIV envelope-specific broadly neutralizing antibody PGT121. Collectively, these data show that GS-9620 can activate HIV production and improve the effector functions that target latently infected cells. GS-9620 may effectively complement orthogonal therapies designed to stimulate antiviral immunity, such as therapeutic vaccines or broadly neutralizing antibodies. Clinical studies are under way to determine if GS-9620 can target HIV reservoirs. IMPORTANCE Though antiretroviral therapies effectively suppress viral replication, they do not eliminate integrated proviral DNA. This stable intermediate of viral infection is persistently

  1. Temporal variability of Polycyclic Aromatic Hydrocarbons (PAHs) in a receptor site of the Puebla-Tlaxcala Valley

    Science.gov (United States)

    Padilla, Z. V.; Torres, R.; Ruiz Suarez, L.; Molina, L. T.

    2013-05-01

    This contribution documents the presence and possible origin of PAHs, their temporal concentration patterns and correlations with other air pollutants in the so-called Puebla-Tlaxcala valley. This valley is located to the east of the Mexico City Metropolitan Area and is a very populated region which suffers of air pollution problems. Emission sources of PAHs include open burning, industrial boilers, automobiles and trucks, but vehicle emissions vary significantly depending on the use of: fuel, engine type and catalytic converter. An important emission source in the Puebla-Tlaxcala region is wood burning for cooking. Therefore, it is expected to have contributions of PAHS from this type of sources. PAHs measurements were performed in an air pollution semi-rural receptor site (Chipilo) southwest the City of Puebla, using an aerosol photoelectric sensor (PAS 2000 CE) to measure the concentration of PAHs and a diffuser charger (DC 2000 CE) to evaluate the active surface (DC) of the particles. The measuring period included March and April of 2012 during the ozne season in central Mexico. The use of these two sensors in parallel has been identified as a fingerprint technique to identify different types of particles from several combustion processes and is a useful tool to identify quantitatively the major source of emissions, as well as to describe thephysical and chemical characteristics of the particles. Correlations between PAHs and DC, with NOx and CO, together with an analysis of atmospheric transport may approximate the possible origin of these particles. The coefficient PAHs / DC associated with backward trajectory analysis represents a tool to identify potential areas of emission. The correlation between PAHs and NOx emissions reflects association with diesel combustion, while the correlation between PAHs and CO, the combustion of gasoline. The results show that vehicle emissions are the major source of PAHs with an associated increase in the concentration of

  2. Regulatory B cells induced by ultraviolet B through toll-like receptor 4 signalling contribute to the suppression of contact hypersensitivity responses in mice.

    Science.gov (United States)

    Liu, Xiaoming; Huang, Haiyan; Gao, Hongbin; Wu, Xia; Zhang, Wei; Yu, Bo; Dou, Xia

    2017-12-05

    Ultraviolet (UV) B irradiation is known to suppress contact hypersensitivity (CHS) responses in mouse models by suppressing immune responses. However, the cellular mechanisms responsible for UVB-induced systemic suppression remain unclear. Regulatory B cells have been reported to play an inhibitory role during CHS. It is presently unknown whether regulatory B cells contribute to the effect of UVB phototherapy. To investigate the inductive effect of UVB on regulatory B cells and the underlying mechanisms by using a CHS mouse model. CHS was induced with oxazolone, and evaluated by histopathology, flow cytometry, and quantitative real-time polymerase chain reaction. We found that UVB irradiation induced regulatory B cell expansion and ameliorated CHS. UVB-induced regulatory B cells contribute to systemic immunosuppression by inhibiting the proliferation of T cells. Moreover, we determined that toll-like receptor (TLR) 4, the expression of which was upregulated in B cells after UVB exposure, played an essential role in the induction of regulatory B cells. Our data identified regulatory B cells as regulators of UVB-induced immunosuppression in CHS, and suggest the importance of the UVB-TLR4 axis in the generation of regulatory B cells. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  3. Peroxisome Proliferator-Activated Receptor-γ Inhibits Transformed Growth of Non-Small Cell Lung Cancer Cells through Selective Suppression of Snail

    Directory of Open Access Journals (Sweden)

    Rashmi Choudhary

    2010-03-01

    Full Text Available Work from our laboratory and others has demonstrated that activation of the nuclear receptor peroxisome proliferator-activated receptor-γ (PPARγ inhibits transformed growth of non-small cell lung cancer (NSCLC cell lines in vitro and in vivo. We have demonstrated that activation of PPARγ promotes epithelial differentiation of NSCLC by increasing expression of E-cadherin, as well as inhibiting expression of COX-2 and nuclear factor-κB. The Snail family of transcription factors, which includes Snail (Snail1, Slug (Snail2, and ZEB1, is an important regulator of epithelial-mesenchymal transition, as well as cell survival. The goal of this study was to determine whether the biological responses to rosiglitazone, a member of the thiazolidinedione family of PPARγ activators, are mediated through the regulation of Snail family members. Our results indicate that, in two independent NSCLC cell lines, rosiglitazone specifically decreased expression of Snail, with no significant effect on either Slug or ZEB1. Suppression of Snail using short hairpin RNA silencing mimicked the effects of PPARγ activation, in inhibiting anchorage-independent growth, promoting acinar formation in three-dimensional culture, and inhibiting invasiveness. This was associated with the increased expression of E-cadherin and decreased expression of COX-2 and matrix metaloproteinases. Conversely, overexpression of Snail blocked the biological responses to rosiglitazone, increasing anchorage-independent growth, invasiveness, and promoting epithelial-mesenchymal transition. The suppression of Snail expression by rosiglitazone seemed to be independent of GSK-3 signaling but was rather mediated through suppression of extracellular signal-regulated kinase activity. These findings suggest that selective regulation of Snail may be critical in mediating the antitumorigenic effects of PPARγ activators.

  4. Toll-like receptor 3-mediated suppression of TRAMP prostate cancer shows the critical role of type I interferons in tumor immune surveillance.

    Science.gov (United States)

    Chin, Arnold I; Miyahira, Andrea K; Covarrubias, Anthony; Teague, Juli; Guo, Beichu; Dempsey, Paul W; Cheng, Genhong

    2010-04-01

    Inflammation has increasingly been recognized as a critical component influencing tumor growth. Recent reports have revealed conflicting evidence for the role of Toll-like receptors (TLR) in modulating tumorigenesis. In our study, we implicate TLR3 in mediating immune surveillance with increased growth of implanted transgenic adenocarcinoma of the mouse prostate (TRAMP) tumors in TLR3(-/-) compared with TLR3(+/+) mice. Activation of TLR3 by polyinosinic-polycytidylic acid (polyI:C) leads to induction of multiple inflammatory pathways, including NF-kappaB, mitogen-activated protein kinases, and interferon (IFN) regulatory factors. We explored the potential of TLR3 stimulation in prostate cancer immunotherapy and showed that treatment with polyI:C can strongly suppress both s.c. implanted TRAMP tumors in syngenic mice as well as orthotopic prostate cancers in TRAMP C57Bl6 x FvB F1 Tg(+/-) transgenic mice. Treated tumors remained well differentiated to moderately differentiated with increased infiltration of T lymphocytes and natural killer (NK) cells compared with poorly differentiated adenocarcinoma observed in untreated tumors. Like TLR3(-/-) mice, IFN-alpha receptor 1 (IFNAR1)(-/-) mice exhibited reduced tumor surveillance and impaired tumor suppression following polyI:C treatment. We observed that type I IFN-dependent induction of cytokines was responsible for NK activation, with depletion of NK cells leading to increased tumor growth as well as expansion of CD4(+)CD25(+)Foxp3(+) T regulatory lymphocytes. Our study therefore delineates the importance of IFNAR-dependent functions in TLR3-mediated tumor suppression and supports the use of TLR3 agonists for prostate cancer immune-based therapies.

  5. Positive modulation of glutamatergic receptors potentiates the suppressive effects of antipsychotics on conditioned avoidance responding in rats

    DEFF Research Database (Denmark)

    Olsen, Christina Kurre; Kreilgaard, Mads; Didriksen, Michael

    2006-01-01

    avoidance response (CAR) behaviour has been widely reported to be a test with high predictive validity for antipsychotic efficacy. We found that D-serine and CX-516, at doses ineffective by themselves, significantly potentiated the suppression of CAR induced by threshold doses of risperidone (0.16 mg/kg, s...

  6. A COMPUTER DOCKING STUDY OF THE BINDING OF POLYCYCLIC AROMATIC HYDROCARBONS AND THEIR METABOLITES TO THE LIGARD-BINDING DOMAIN OF THE ESTROGEN RECEPTOR

    Science.gov (United States)

    Polycyclic aromatic hydrocarbons (PAHs) are a class of ubiquitous, anthropogenic chemicals found in the environment. In the present study, computational methods are used to evaluate their potential estrogenicity and the contribution chemicals in this class make to environmental e...

  7. Thymoquinone suppression of the human hepatocellular carcinoma cell growth involves inhibition of IL-8 expression, elevated levels of TRAIL receptors, oxidative stress and apoptosis.

    Science.gov (United States)

    Ashour, Abdelkader E; Abd-Allah, Adel R; Korashy, Hesham M; Attia, Sabry M; Alzahrani, Abdelrahman Z; Saquib, Quaiser; Bakheet, Saleh A; Abdel-Hamied, Hala E; Jamal, Shazia; Rishi, Arun K

    2014-04-01

    Hepatocellular carcinoma (HCC) is the fourth most common solid tumor worldwide. The chemokine interleukin-8 (IL-8) is overexpressed in HCC and is a potential target for therapy. Although the transcription factor NF-κB regulates IL-8 expression, and while thymoquinone (TQ; the most bioactive constituent of black seed oil) inhibits NF-κB activity, the precise mechanisms by which TQ regulates IL-8 and cancer cell growth remain to be clarified. Here, we report that TQ inhibited growth of HCC cells in a dose- and time-dependent manner, caused G2M cell cycle arrest, and stimulated apoptosis. Apoptosis was substantiated by activation of caspase-3 and -9, as well as cleavage of poly(ADP-ribose)polymerase. TQ treatments inhibited expression of NF-κB and suppressed IL-8 and its receptors. TQ treatments caused increased levels of reactive oxygen species (ROS) and mRNAs of oxidative stress-related genes, NQO1 and HO-1. Pretreatment of HepG2 cells with N-acetylcysteine, a scavenger of ROS, prevented TQ-induced cell death. TQ treatment stimulated mRNA expression of pro-apoptotic Bcl-xS and TRAIL death receptors, and inhibited expression of the anti-apoptotic gene Bcl-2. TQ enhanced TRAIL-induced death of HepG2 cells, in part by up-regulating TRAIL death receptors, inhibiting NF-κB and IL-8 and stimulating apoptosis. Altogether, these findings provide insights into the pleiotropic molecular mechanisms of TQ-dependent suppression of HCC cell growth and underscore potential of this compound as anti-HCC drug.

  8. Dual regulation of receptor tyrosine kinase genes EGFR and c-Met by the tumor-suppressive microRNA-23b/27b cluster in bladder cancer.

    Science.gov (United States)

    Chiyomaru, Takeshi; Seki, Naohiko; Inoguchi, Satoru; Ishihara, Tomoaki; Mataki, Hiroko; Matsushita, Ryosuke; Goto, Yusuke; Nishikawa, Rika; Tatarano, Shuichi; Itesako, Toshihiko; Nakagawa, Masayuki; Enokida, Hideki

    2015-02-01

    Recent clinical trials of chemotherapeutics for advanced bladder cancer (BC) have shown limited benefits. Therefore, new prognostic markers and more effective treatment strategies are required. One approach to achieve these goals is through the analysis of RNA networks. Our recent studies of microRNA (miRNA) expression signatures revealed that the microRNA-23b/27b (miR-23b/27b) cluster is frequently downregulated in various types of human cancers. However, the functional role of the miR-23b/27b cluster in BC cells is still unknown. Thus, the aim of the present study was to investigate the functional significance of the miR-23b/27b cluster and its regulated molecular targets, with an emphasis on its contributions to BC oncogenesis and metastasis. The expression levels of the miR-23b/27b cluster were significantly reduced in BC clinical specimens. Restoration of mature miR-23b or miR-27b miRNAs significantly inhibited cancer cell migration and invasion, suggesting that these clustered miRNAs function as tumor suppressors. Gene expression data and in silico analysis demonstrated that the genes coding for the epidermal growth factor receptor (EGFR) and hepatocyte growth factor receptor (c-Met) were potential targets of the miR-23b/27b cluster. Luciferase reporter assays and western blotting demonstrated that EGFR and c-Met receptor trypsine kinases were directly regulated by these clustered miRNAs. We conclude that the decreased expression of the tumor-suppressive miR-23b/27b cluster enhanced cancer cell proliferation, migration and invasion in BC through direct regulation of EGFR and c-Met signaling pathways. Our data on RNA networks regulated by tumor-suppressive miR-23b/27b provide new insights into the potential mechanisms of BC oncogenesis and metastasis.

  9. [STUDYING THE ROLE OF BRAIN MELANOCORTIN RECEPTORS IN THE SUPPRESSING OF FOOD INTAKE UNDER ETHER STRESS IN MICE].

    Science.gov (United States)

    Bazhan, N M; Kulikova, E V; Makarova, E N; Yakovleva, T V; Kazantseva, A Yu

    2015-12-01

    Melanocortin (MC) system regulates food intake under the rest conditions. Stress inhibits food intake. It is not clear whether brain MC system is involved in stress-induced anorexia in mice. The aim of the work was to investigate the effect of pharmacological blockade and activation of brain MC receptors on food intake under stress. C57B1/6J male mice were subjected to ether stress (0.5 minute ether anesthesia) before the administration of saline solution or synthetic non-selective blocker (SHU9119) or agonist (Melanotan II) of MC receptors into the lateral brain ventricle. Food intake was pre-stimulated with 17 hours of fasting in all mice. Ether stress decreased food intake, increased the plasma corticosterone level and hypothalamic mRNA AgRP (natural MC receptor antagonist) level at 1 hour after the stress. Pharmacological blockade of the MC receptors weakened stress-induced anorexia and decreased mRNA AgRP level in the hypothalamus. Pharmacological stimulation of the MC receptors enhanced ether stress-induced anorexia and hypercortisolism. Thus, our data demonstrated that the central MC system was involved in the development of stress-induced anorexia in mice.

  10. Apigenin suppresses migration and invasion of transformed cells through down-regulation of C-X-C chemokine receptor 4 expression

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Lei; Kuang, Lisha; Hitron, John Andrew; Son, Young-Ok; Wang, Xin; Budhraja, Amit [Graduate Center for Toxicology, College of Medicine, University of Kentucky, Lexington, KY 40536 (United States); Lee, Jeong-Chae [Graduate Center for Toxicology, College of Medicine, University of Kentucky, Lexington, KY 40536 (United States); Institute of Oral Biosciences and BK21 Program, Research Center of Bioactive Materials, Chonbuk National University, Jeonju 561-756 (Korea, Republic of); Pratheeshkumar, Poyil [Graduate Center for Toxicology, College of Medicine, University of Kentucky, Lexington, KY 40536 (United States); Chen, Gang [Department of Internal Medicine, University of Kentucky College of Medicine, Lexington, KY 40536 (United States); Zhang, Zhuo [Graduate Center for Toxicology, College of Medicine, University of Kentucky, Lexington, KY 40536 (United States); Luo, Jia [Department of Internal Medicine, University of Kentucky College of Medicine, Lexington, KY 40536 (United States); Shi, Xianglin, E-mail: xshi5@email.uky.edu [Graduate Center for Toxicology, College of Medicine, University of Kentucky, Lexington, KY 40536 (United States)

    2013-10-01

    Environmental exposure to arsenic is known to cause various cancers. There are some potential relationships between cell malignant transformation and C-X-C chemokine receptor type 4 (CXCR4) expressions. Metastasis, one of the major characteristics of malignantly transformed cells, contributes to the high mortality of cells. CXCR4 and its natural chemokine ligand C-X-C motif ligand 12 (CXCL12) play a critical role in metastasis. Therefore, identification of nutritional factors which are able to inhibit CXCR4 is important for protection from environmental arsenic-induced carcinogenesis and for abolishing metastasis of malignantly transformed cells. The present study demonstrates that apigenin (4′,5,7-trihydroxyflavone), a natural dietary flavonoid, suppressed CXCR4 expression in arsenic-transformed Beas-2B cells (B-AsT) and several other types of transformed/cancer cells in a dose- and time-dependent manner. Neither proteasome nor lysosome inhibitor had any effect in reducing the apigenin-induced down-regulation of CXCR4, indicating that apigenin-induced down-regulation of CXCR4 is not due to proteolytic degradation. The down-regulation of CXCR4 is mainly due to the inhibition of nuclear factor κB (NF-κB) transcriptional activity. Apigenin also abolished migration and invasion of transformed cells induced by CXCL12. In a xenograft mouse model, apigenin down-regulated CXCR4 expression and suppressed tumor growth. Taken together, our results show that apigenin is a novel inhibitor of CXCR4 expression. This dietary flavonoid has the potential to suppress migration and invasion of transformed cells and prevent environmental arsenic-induced carcinogenesis. - Highlights: • Apigenin has a potential in preventing environmental arsenic induced carcinogenesis. • Apigenin suppresses CXCR4 in malignant transformed cells in vitro and in vivo. • The down-regulation of CXCR4 is mainly due to inhibition of NF-κB activity.

  11. Cysteine protease antigens cleave CD123, the α subunit of murine IL-3 receptor, on basophils and suppress IL-3-mediated basophil expansion

    Energy Technology Data Exchange (ETDEWEB)

    Nishikado, Hideto [Atopy (Allergy) Research Center, Juntendo University Graduate School of Medicine, Tokyo (Japan); Fujimura, Tsutomu; Taka, Hikari; Mineki, Reiko [Laboratory of Proteomics and Biomolecular Science, BioMedical Research Center, Juntendo University Graduate School of Medicine, Tokyo (Japan); Ogawa, Hideoki; Okumura, Ko [Atopy (Allergy) Research Center, Juntendo University Graduate School of Medicine, Tokyo (Japan); Takai, Toshiro, E-mail: t-takai@juntendo.ac.jp [Atopy (Allergy) Research Center, Juntendo University Graduate School of Medicine, Tokyo (Japan)

    2015-05-01

    Th2 type immune responses are essential for protective immunity against parasites and play crucial roles in allergic disorders. Helminth parasites secrete a variety of proteases for their infectious cycles including for host entry, tissue migration, and suppression of host immune effector cell function. Furthermore, a number of pathogen-derived antigens, as well as allergens such as papain, belong to the family of cysteine proteases. Although the link between protease activity and Th2 type immunity is well documented, the mechanisms by which proteases regulate host immune responses are largely unknown. Here, we demonstrate that the cysteine proteases papain and bromelain selectively cleave the α subunit of the IL-3 receptor (IL-3Rα/CD123) on the surface of murine basophils. The decrease in CD123 expression on the cell surface, and the degradation of the extracellular domain of recombinant CD123 were dependent on the protease activity of papain and bromelain. Pre-treatment of murine basophils with papain resulted in inhibition of IL-3-IL-3R signaling and suppressed IL-3- but not thymic stromal lymphopoietin-induced expansion of basophils in vitro. Our unexpected findings illuminate a novel mechanism for the regulation of basophil functions by protease antigens. Because IL-3 plays pivotal roles in the activation and proliferation of basophils and in protective immunity against helminth parasites, pathogen-derived proteases might contribute to the pathogenesis of infections by regulating IL-3-mediated functions in basophils. - Highlights: • We identified the murine IL3R as a novel target of papain-family cysteine proteases. • Papain-family cysteine proteases cleaved IL3Rα/CD123 on murine basophils. • Papain suppressed IL3- but not TSLP-induced expansion of murine basophils. • The inactivation of IL3R might be a strategy for pathogens to suppress host immunity.

  12. Human monoclonal antibodies against glucagon receptor improve glucose homeostasis by suppression of hepatic glucose output in diet-induced obese mice.

    Directory of Open Access Journals (Sweden)

    Wook-Dong Kim

    Full Text Available AIM: Glucagon is an essential regulator of hepatic glucose production (HGP, which provides an alternative therapeutic target for managing type 2 diabetes with glucagon antagonists. We studied the effect of a novel human monoclonal antibody against glucagon receptor (GCGR, NPB112, on glucose homeostasis in diet-induced obese (DIO mice. METHODS: The glucose-lowering efficacy and safety of NPB112 were investigated in DIO mice with human GCGR for 11 weeks, and a hyperinsulinemic-euglycemic clamp study was conducted to measure HGP. RESULTS: Single intraperitoneal injection of NPB112 with 5 mg/kg effectively decreased blood glucose levels in DIO mice for 5 days. A significant reduction in blood glucose was observed in DIO mice treated with NPB112 at a dose ≥5 mg/kg for 6 weeks, and its glucose-lowering effect was dose-dependent. Long-term administration of NPB112 also caused a mild 29% elevation in glucagon level, which was returned to the normal range after discontinuation of treatment. The clamp study showed that DIO mice injected with NPB112 at 5 mg/kg were more insulin sensitive than control mice, indicating amelioration of insulin resistance by treatment with NPB112. DIO mice treated with NPB112 showed a significant improvement in the ability of insulin to suppress HGP, showing a 33% suppression (from 8.3 mg/kg/min to 5.6 mg/kg/min compared to the 2% suppression (from 9.8 mg/kg/min to 9.6 mg/kg/min in control mice. In addition, no hypoglycemia or adverse effect was observed during the treatment. CONCLUSIONS: A novel human monoclonal GCGR antibody, NPB112, effectively lowered the glucose level in diabetic animal models with mild and reversible hyperglucagonemia. Suppression of excess HGP with NPB112 may be a promising therapeutic modality for the treatment of type 2 diabetes.

  13. Central glucagon-like peptide 1 receptor-induced anorexia requires glucose metabolism-mediated suppression of AMPK and is impaired by central fructose.

    Science.gov (United States)

    Burmeister, Melissa A; Ayala, Jennifer; Drucker, Daniel J; Ayala, Julio E

    2013-04-01

    Glucagon-like peptide-1 (GLP-1) suppresses food intake via activation of a central (i.e., brain) GLP-1 receptor (GLP-1R). Central AMP-activated protein kinase (AMPK) is a nutrient-sensitive regulator of food intake that is inhibited by anorectic signals. The anorectic effect elicited by hindbrain GLP-1R activation is attenuated by the AMPK stimulator AICAR. This suggests that central GLP-1R activation suppresses food intake via inhibition of central AMPK. The present studies examined the mechanism(s) by which central GLP-1R activation inhibits AMPK. Supporting previous findings, AICAR attenuated the anorectic effect elicited by intracerebroventricular (icv) administration of the GLP-1R agonist exendin-4 (Ex-4). We demonstrate that Ex-4 stimulates glycolysis and suppresses AMPK phosphorylation in a glucose-dependent manner in hypothalamic GT1-7 cells. This suggests that inhibition of AMPK and food intake by Ex-4 requires central glucose metabolism. Supporting this, the glycolytic inhibitor 2-deoxyglucose (2-DG) attenuated the anorectic effect of Ex-4. However, icv glucose did not enhance the suppression of food intake by Ex-4. AICAR had no effect on Ex-4-mediated reduction in locomotor activity. We also tested whether other carbohydrates affect the anorectic response to Ex-4. Intracerebroventricular pretreatment with the sucrose metabolite fructose, an AMPK activator, attenuated the anorectic effect of Ex-4. This potentially explains the increased food intake observed in sucrose-fed mice. In summary, we propose a model whereby activation of the central GLP-1R reduces food intake via glucose metabolism-dependent inhibition of central AMPK. We also suggest that fructose stimulates food intake by impairing central GLP-1R action. This has significant implications given the correlation between sugar consumption and obesity.

  14. Swimming suppresses hepatic vitellogenesis in European female silver eels as shown by expression of the estrogen receptor 1, vitellogenin1 and vitellogenin2 in the liver

    Directory of Open Access Journals (Sweden)

    Nieveen Maaike C

    2010-03-01

    Full Text Available Abstract Background When European silver eels (Anguilla anguilla venture into the Atlantic Ocean for their 6,000 km semelparous spawning run to the Sargasso Sea, they are still in a prepubertal stage. Further sexual development appears to be blocked by dopaminergic inhibition of hypothalamus and pituitary activity. Recently, we found that swimming for several weeks in freshwater stimulated the incorporation of fat droplets in the oocytes. So, it was hypothesized that long term swimming in seawater would release the inhibition further and would also stimulate the production of vitellogenin by the liver. Methods For this study a swim-flume was constructed to allow simulated migration of migratory female silver eels for 3 months (1,420 km in natural seawater at 20 degrees C. Primers were designed for polymerase chain reactions to measure the mRNA expression of estrogen receptor 1 (esr1, vitellogenin1 (vtg1 and vitellogenin2 (vtg2 genes in the liver of European female silver eels. Results In comparison to resting eels, swimming eels showed a diminished expression of esr1, vtg1 and vtg2 in the liver. They also had lower plasma calcium (Ca; indicative of vitellogenin levels in their blood. This showed that vitellogenesis is more strongly suppressed in swimming than in resting eels. However, when eels were subsequently stimulated by 3 weekly carp pituitary extract injections, the expression of the same genes and plasma levels of Ca strongly increased in both groups to similar levels, thus equalizing the initial differences between resting and swimming. Conclusions It is concluded that vitellogenesis remains suppressed during resting and even more during swimming. The fact that swimming stimulates fat deposition in the oocytes but suppresses vitellogenesis indicates that these events are separated in nature and occur sequentially. Swimming-suppressed vitellogenesis may imply that in nature eels undergo vitellogenesis and final maturation near or at the

  15. Minocycline suppresses interleukine-6, its receptor system and signaling pathways and impairs migration, invasion and adhesion capacity of ovarian cancer cells: in vitro and in vivo studies.

    Directory of Open Access Journals (Sweden)

    Parvin Ataie-Kachoie

    Full Text Available Interleukin (IL-6 has been shown to be a major contributing factor in growth and progression of ovarian cancer. The cytokine exerts pro-tumorigenic activity through activation of several signaling pathways in particular signal transducer and activator of transcription (STAT3 and extracellular signal-regulated kinase (ERK1/2. Hence, targeting IL-6 is becoming increasingly attractive as a treatment option in ovarian cancer. Here, we investigated the effects of minocycline on IL-6 and its signaling pathways in ovarian cancer. In vitro, minocycline was found to significantly suppress both constitutive and IL-1β or 4-hydroxyestradiol (4-OH-E2-stimulated IL-6 expression in human ovarian cancer cells; OVCAR-3, SKOV-3 and CAOV-3. Moreover, minocycline down-regulated two major components of IL-6 receptor system (IL-6Rα and gp130 and blocked the activation of STAT3 and ERK1/2 pathways leading to suppression of the downstream product MCL-1. In female nude mice bearing intraperitoneal OVCAR-3 tumors, acute administration (4 and 24 h of minocycline (30 mg/kg led to suppression of IL-6. Even single dose of minocycline was effective at significantly lowering plasma and tumor IL-6 levels. In line with this, tumoral expression of p-STAT3, p-ERK1/2 and MCL-1 were decreased in minocycline-treated mice. Evaluation of the functional implication of minocycline on metastatic activity revealed the capacity of minocycline to inhibit cellular migration, invasion and adhesion associated with down-regulation of matrix metalloproteinases (MMP-2 and 9. Thus, the data suggest a potential role for minocycline in suppressing IL-6 expression and activity. These effects may prove to be an important attribute to the upcoming clinical trials of minocycline in ovarian cancer.

  16. Minocycline Suppresses Interleukine-6, Its Receptor System and Signaling Pathways and Impairs Migration, Invasion and Adhesion Capacity of Ovarian Cancer Cells: In Vitro and In Vivo Studies

    Science.gov (United States)

    Ataie-Kachoie, Parvin; Morris, David L.; Pourgholami, Mohammad H.

    2013-01-01

    Interleukin (IL)-6 has been shown to be a major contributing factor in growth and progression of ovarian cancer. The cytokine exerts pro-tumorigenic activity through activation of several signaling pathways in particular signal transducer and activator of transcription (STAT3) and extracellular signal-regulated kinase (ERK)1/2. Hence, targeting IL-6 is becoming increasingly attractive as a treatment option in ovarian cancer. Here, we investigated the effects of minocycline on IL-6 and its signaling pathways in ovarian cancer. In vitro, minocycline was found to significantly suppress both constitutive and IL-1β or 4-hydroxyestradiol (4-OH-E2)-stimulated IL-6 expression in human ovarian cancer cells; OVCAR-3, SKOV-3 and CAOV-3. Moreover, minocycline down-regulated two major components of IL-6 receptor system (IL-6Rα and gp130) and blocked the activation of STAT3 and ERK1/2 pathways leading to suppression of the downstream product MCL-1. In female nude mice bearing intraperitoneal OVCAR-3 tumors, acute administration (4 and 24 h) of minocycline (30 mg/kg) led to suppression of IL-6. Even single dose of minocycline was effective at significantly lowering plasma and tumor IL-6 levels. In line with this, tumoral expression of p-STAT3, p-ERK1/2 and MCL-1 were decreased in minocycline-treated mice. Evaluation of the functional implication of minocycline on metastatic activity revealed the capacity of minocycline to inhibit cellular migration, invasion and adhesion associated with down-regulation of matrix metalloproteinases (MMP)-2 and 9. Thus, the data suggest a potential role for minocycline in suppressing IL-6 expression and activity. These effects may prove to be an important attribute to the upcoming clinical trials of minocycline in ovarian cancer. PMID:23593315

  17. Aryl hydrocarbon receptor is necessary to protect fetal human pulmonary microvascular endothelial cells against hyperoxic injury: Mechanistic roles of antioxidant enzymes and RelB

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Shaojie; Patel, Ananddeep; Chu, Chun; Jiang, Weiwu; Wang, Lihua; Welty, Stephen E.; Moorthy, Bhagavatula; Shivanna, Binoy, E-mail: shivanna@bcm.edu

    2015-07-15

    Hyperoxia contributes to the development of bronchopulmonary dysplasia (BPD) in premature infants. Activation of the aryl hydrocarbon receptor (AhR) protects adult and newborn mice against hyperoxic lung injury by mediating increases in the expression of phase I (cytochrome P450 (CYP) 1A) and phase II (NADP(H) quinone oxidoreductase (NQO1)) antioxidant enzymes (AOE). AhR positively regulates the expression of RelB, a component of the nuclear factor-kappaB (NF-κB) protein that contributes to anti-inflammatory processes in adult animals. Whether AhR regulates the expression of AOE and RelB, and protects fetal primary human lung cells against hyperoxic injury is unknown. Therefore, we tested the hypothesis that AhR-deficient fetal human pulmonary microvascular endothelial cells (HPMEC) will have decreased RelB activation and AOE, which will in turn predispose them to increased oxidative stress, inflammation, and cell death compared to AhR-sufficient HPMEC upon exposure to hyperoxia. AhR-deficient HPMEC showed increased hyperoxia-induced reactive oxygen species (ROS) generation, cleavage of poly(ADP-ribose) polymerase (PARP), and cell death compared to AhR-sufficient HPMEC. Additionally, AhR-deficient cell culture supernatants displayed increased macrophage inflammatory protein 1α and 1β, indicating a heightened inflammatory state. Interestingly, loss of AhR was associated with a significantly attenuated CYP1A1, NQO1, superoxide dismutase 1(SOD1), and nuclear RelB protein expression. These findings support the hypothesis that decreased RelB activation and AOE in AhR-deficient cells is associated with increased hyperoxic injury compared to AhR-sufficient cells. - Highlights: • AhR deficiency potentiates oxygen toxicity in human fetal lung cells. • Deficient AhR signaling increases hyperoxia-induced cell death. • AhR deficiency increases hyperoxia-induced ROS generation and inflammation. • Anti-oxidant enzyme levels are attenuated in AhR-deficient lung cells

  18. New insights to the role of aryl hydrocarbon receptor in bone phenotype and in dioxin-induced modulation of bone microarchitecture and material properties

    Energy Technology Data Exchange (ETDEWEB)

    Herlin, Maria, E-mail: maria.herlin@ki.se [Institute of Environmental Medicine, Karolinska Institutet, Stockholm (Sweden); Finnilä, Mikko A.J., E-mail: mikko.finnila@oulu.fi [Department of Medical Technology, Institute of Biomedicine, University of Oulu, Oulu (Finland); Department of Anatomy and Cell Biology, Institute of Biomedicine, University of Oulu, Oulu (Finland); Zioupos, Peter, E-mail: p.zioupos@cranfield.ac.uk [Biomechanics Laboratories, Department of Engineering and Applied Science, Cranfield University, Shrivenham SN6 8LA (United Kingdom); Aula, Antti, E-mail: antti.aula@gmail.com [Department of Medical Physics, Imaging Centre, Tampere University Hospital, Tampere (Finland); Department of Biomedical Engineering, Tampere University of Technology, Tampere (Finland); Risteli, Juha, E-mail: juha.risteli@ppshp.fi [Department of Clinical Chemistry, Oulu University Hospital, Oulu (Finland); Miettinen, Hanna M., E-mail: hanna.miettinen@crl.com [Department of Environmental Health, National Institute for Health and Welfare, Kuopio (Finland); Jämsä, Timo, E-mail: timo.jamsa@oulu.fi [Department of Medical Technology, Institute of Biomedicine, University of Oulu, Oulu (Finland); Department of Diagnostic Radiology, Oulu University Hospital, Oulu (Finland); Tuukkanen, Juha, E-mail: juha.tuukkanen@oulu.fi [Department of Anatomy and Cell Biology, Institute of Biomedicine, University of Oulu, Oulu (Finland); Korkalainen, Merja, E-mail: merja.korkalainen@thl.fi [Department of Environmental Health, National Institute for Health and Welfare, Kuopio (Finland); Håkansson, Helen, E-mail: Helen.Hakansson@ki.se [Institute of Environmental Medicine, Karolinska Institutet, Stockholm (Sweden); Viluksela, Matti, E-mail: matti.viluksela@thl.fi [Department of Environmental Health, National Institute for Health and Welfare, Kuopio (Finland); Department of Environmental Science, University of Eastern Finland, Kuopio (Finland)

    2013-11-15

    Bone is a target for high affinity aryl hydrocarbon receptor (AHR) ligands, such as dioxins. Although bone morphology, mineral density and strength are sensitive endpoints of dioxin toxicity, less is known about effects on bone microarchitecture and material properties. This study characterizes TCDD-induced modulations of bone tissue, and the role of AHR in dioxin-induced bone toxicity and for normal bone phenotype. Six AHR-knockout (Ahr{sup −/−}) and wild-type (Ahr{sup +/+}) mice of both genders were exposed to TCDD weekly for 10 weeks, at a total dose of 200 μg/kg bw. Bones were examined with micro-computed tomography, nanoindentation and biomechanical testing. Serum levels of bone remodeling markers were analyzed, and the expression of genes related to osteogenic differentiation was profiled using PCR array. In Ahr{sup +/+} mice, TCDD-exposure resulted in harder bone matrix, thinner and more porous cortical bone, and a more compact trabecular bone compartment. Bone remodeling markers and altered expression of a number of osteogenesis related genes indicated imbalanced bone remodeling. Untreated Ahr{sup −/−} mice displayed a slightly modified bone phenotype as compared with untreated Ahr{sup +/+} mice, while TCDD exposure caused only a few changes in bones of Ahr{sup −/−} mice. Part of the effects of both TCDD-exposure and AHR-deficiency were gender dependent. In conclusion, exposure of adult mice to TCDD resulted in harder bone matrix, thinner cortical bone, mechanically weaker bones and most notably, increased trabecular bone volume fraction in Ahr{sup +/+} mice. AHR is involved in bone development of a normal bone phenotype, and is crucial for manifestation of TCDD-induced bone alterations. - Highlights: • TCDD disrupts bone remodeling resulting in altered cortical and trabecular bone. • In trabecular bone an anabolic effect is observed. • Cortical bone is thinner, more porous, harder, stiffer and mechanically weaker. • AHR ablation

  19. Aberrant NLRP3 inflammasome associated with aryl hydrocarbon receptor potentially contributes to the imbalance of T-helper cells in patients with acute myeloid leukemia.

    Science.gov (United States)

    Jia, Yan; Zhang, Chen; Hua, Mingqiang; Wang, Min; Chen, Ping; Ma, Daoxin

    2017-12-01

    Acute myeloid leukemia (AML) is a hematological malignancy in which the immune response serves a pivotal role in progression. Aryl hydrocarbon receptor (AHR) is involved in the modulation of the immune system, particularly in the differentiation of T-helper cell (Th) subsets. Although the NLR family pyrin domain-containing 3 (NLRP3) inflammasome has been implicated as essential in the pathogenesis of autoimmune and inflammatory diseases, the role it serves in the development of AML remains unknown. Therefore, in order to identify and describe the possible roles of AHR, as well as NLRP3 inflammasome, in the pathogenesis of AML and their relationship with Th subsets (Th1 Th22), the present study investigated the mRNA expression levels of AHR and NLRP3 inflammasome molecules in the peripheral blood and bone marrow. Concentrations of plasma IL-18 were also investigated in peripheral blood by ELISA, as well as the proportions of Th22 and Th1. In the present study, there were three groups: Newly diagnosed (ND) patients; complete remission (CR); and normal controls. A markedly increased expression of NLRP3 inflammasome molecules in bone marrow mononuclear cells (BMMCs) from newly diagnosed (ND) patients compared with patients in complete remission (CR) was identified. NLRP3 inflammasome molecules were also observed to be aberrantly expressed in peripheral blood (PB) mononuclear cells (PBMCs), accompanied with aberrant interleukin (IL)-18 levels in PB plasma. The relative level of IL-18 mRNA became normal after the ND patients with AML achieved CR. In bone marrow, the expression of AHR was significantly higher in ND patients than in CR patients. Furthermore, the expression level of NLRP3 inflammasome molecules was significantly correlated with AHR expression in patients with AML. In the Th subsets, a significantly increased proportion of Th22 in PB from ND patients compared with CR patients or controls was identified, accompanied with decreased Th1. It was concluded that

  20. Angiotensin AT1 Receptor-associated protein Arap1 in the Kidney Vasculature is Suppressed by Angiotensin II

    DEFF Research Database (Denmark)

    Doblinger, Elisabeth; Hoecherl, Klaus; Mederle, Katharina

    2012-01-01

    Arap1 is a protein that interacts with angiotensin II type 1 (AT1) receptors and facilitates increased AT1 receptor surface expression in vitro. In the present study we assessed the tissue localization and regulation of Arap1 in vivo. Arap1 was found in various mouse organs with highest expression...... in the heart, kidney, aorta, and adrenal gland. Renal Arap1 protein was restricted to the vasculature and to glomerular mesangial cells and was absent from tubular epithelia. A similar localization was found in human kidneys. To test the hypothesis that angiotensin II may control renal Arap1 expression, mice...

  1. Selective suppression of chemokine receptor CXCR3 expression by interferon-beta1a in multiple sclerosis

    DEFF Research Database (Denmark)

    Sørensen, Torben Lykke; Sellebjerg, F

    2002-01-01

    We studied the expression of chemokine receptors CCR1, CCR2, CCR3, CCR5, and CXCR3 on CD4 and CD8 positive T cells, and on CD14 positive monocytes in blood from 10 patients with relapsing-remitting multiple sclerosis (MS) at initiation of interferon (IFN)-beta treatment, after 1 month and after 3...

  2. Beta-2 adrenergic receptors increase TREG cell suppression in an OVA-induced allergic asthma mouse model when mice are moderate aerobically exercised.

    Science.gov (United States)

    Dugger, Kari J; Chrisman, Taylor; Sayner, Sarah L; Chastain, Parker; Watson, Kacie; Estes, Robert

    2018-02-17

    The potency of T regulatory (TREG) cells to inhibit T helper (Th)-driven immune cell responses has been linked to increased intracellular cyclic-AMP (cAMP) levels of TREG cells. In an ovalbumin (OVA)-driven allergic asthma mouse model, moderate aerobic exercise increases TREG cell function in a contact-dependent manner that leads to a significant reduction in chronic inflammation and restoration of lung function. However, the mechanism, whereby exercise increases TREG function, remains unknown and was the focus of these investigations. Exercise can communicate with TREG cells by their expression of β2-adrenergic receptors (β2-AR). Activation of these receptors results in an increase in intracellular levels of cyclic-AMP, potentially creating a potent inhibitor of Th cell responses. For the allergic asthma model, female wildtype BALB/c mice were challenged with OVA, and exercised (13.5 m/min for 45 min) 3×/week for 4 weeks. TREG cells were isolated from all mouse asthma/exercise groups, including β2-AR -/- mice, to test suppressive function and intracellular cAMP levels. In these studies, cAMP levels were increased in TREG cells isolated from exercised mice. When β2-AR expression was absent on TREG cells, cAMP levels were significantly decreased. Correlatively, their suppressive function was compromised. Next, TREG cells from all mouse groups were tested for suppressive function after treatment with either a pharmaceutical β2-adrenergic agonist or an effector-specific cAMP analogue. These experiments showed TREG cell function was increased when treated with either a β2-adrenergic agonist or effector-specific cAMP analogue. Finally, female wildtype BALB/c mice were antibody-depleted of CD25 + CD4 + TREG cells (anti-CD25). Twenty-four hours after TREG depletion, either β2-AR -/- or wildtype TREG cells were adoptively transferred. Recipient mice underwent the asthma/exercise protocols. β2-AR -/- TREG cells isolated from these mice showed no increase in

  3. Apparatus for hydrocarbon extraction

    Science.gov (United States)

    Bohnert, George W.; Verhulst, Galen G.

    2013-03-19

    Systems and methods for hydrocarbon extraction from hydrocarbon-containing material. Such systems and methods relate to extracting hydrocarbon from hydrocarbon-containing material employing a non-aqueous extractant. Additionally, such systems and methods relate to recovering and reusing non-aqueous extractant employed for extracting hydrocarbon from hydrocarbon-containing material.

  4. Antihistamines suppress upregulation of histidine decarboxylase gene expression with potencies different from their binding affinities for histamine H1 receptor in toluene 2,4-diisocyanate-sensitized rats.

    Science.gov (United States)

    Mizuguchi, Hiroyuki; Das, Asish K; Maeyama, Kazutaka; Dev, Shrabanti; Shahriar, Masum; Kitamura, Yoshiaki; Takeda, Noriaki; Fukui, Hiroyuki

    2016-04-01

    Antihistamines inhibit histamine signaling by blocking histamine H1 receptor (H1R) or suppressing H1R signaling as inverse agonists. The H1R gene is upregulated in patients with pollinosis, and its expression level is correlated with the severity of nasal symptoms. Here, we show that antihistamine suppressed upregulation of histidine decarboxylase (HDC) mRNA expression in patients with pollinosis, and its expression level was correlated with that of H1R mRNA. Certain antihistamines, including mepyramine and diphenhydramine, suppress toluene-2,4-diisocyanate (TDI)-induced upregulation of HDC gene expression and increase HDC activity in TDI-sensitized rats. However, d-chlorpheniramine did not demonstrate any effect. The potencies of antihistamine suppressive effects on HDC mRNA elevation were different from their H1R receptor binding affinities. In TDI-sensitized rats, the potencies of antihistamine inhibitory effects on sneezing in the early phase were related to H1R binding. In contrast, the potencies of their inhibitory effects on sneezing in the late phase were correlated with those of suppressive effects on HDC mRNA elevation. Data suggest that in addition to the antihistaminic and inverse agonistic activities, certain antihistamines possess additional properties unrelated to receptor binding and alleviate nasal symptoms in the late phase by inhibiting synthesis and release of histamine by suppressing HDC gene transcription. Copyright © 2016 The Authors. Production and hosting by Elsevier B.V. All rights reserved.

  5. Probenecid inhibits the human bitter taste receptor TAS2R16 and suppresses bitter perception of salicin.

    Science.gov (United States)

    Greene, Tiffani A; Alarcon, Suzanne; Thomas, Anu; Berdougo, Eli; Doranz, Benjamin J; Breslin, Paul A S; Rucker, Joseph B

    2011-01-01

    Bitter taste stimuli are detected by a diverse family of G protein-coupled receptors (GPCRs) expressed in gustatory cells. Each bitter taste receptor (TAS2R) responds to an array of compounds, many of which are toxic and can be found in nature. For example, human TAS2R16 (hTAS2R16) responds to β-glucosides such as salicin, and hTAS2R38 responds to thiourea-containing molecules such as glucosinolates and phenylthiocarbamide (PTC). While many substances are known to activate TAS2Rs, only one inhibitor that specifically blocks bitter receptor activation has been described. Here, we describe a new inhibitor of bitter taste receptors, p-(dipropylsulfamoyl)benzoic acid (probenecid), that acts on a subset of TAS2Rs and inhibits through a novel, allosteric mechanism of action. Probenecid is an FDA-approved inhibitor of the Multidrug Resistance Protein 1 (MRP1) transporter and is clinically used to treat gout in humans. Probenecid is also commonly used to enhance cellular signals in GPCR calcium mobilization assays. We show that probenecid specifically inhibits the cellular response mediated by the bitter taste receptor hTAS2R16 and provide molecular and pharmacological evidence for direct interaction with this GPCR using a non-competitive (allosteric) mechanism. Through a comprehensive analysis of hTAS2R16 point mutants, we define amino acid residues involved in the probenecid interaction that result in decreased sensitivity to probenecid while maintaining normal responses to salicin. Probenecid inhibits hTAS2R16, hTAS2R38, and hTAS2R43, but does not inhibit the bitter receptor hTAS2R31 or non-TAS2R GPCRs. Additionally, structurally unrelated MRP1 inhibitors, such as indomethacin, fail to inhibit hTAS2R16 function. Finally, we demonstrate that the inhibitory activity of probenecid in cellular experiments translates to inhibition of bitter taste perception of salicin in humans. This work identifies probenecid as a pharmacological tool for understanding the cell biology of

  6. Probenecid inhibits the human bitter taste receptor TAS2R16 and suppresses bitter perception of salicin.

    Directory of Open Access Journals (Sweden)

    Tiffani A Greene

    Full Text Available Bitter taste stimuli are detected by a diverse family of G protein-coupled receptors (GPCRs expressed in gustatory cells. Each bitter taste receptor (TAS2R responds to an array of compounds, many of which are toxic and can be found in nature. For example, human TAS2R16 (hTAS2R16 responds to β-glucosides such as salicin, and hTAS2R38 responds to thiourea-containing molecules such as glucosinolates and phenylthiocarbamide (PTC. While many substances are known to activate TAS2Rs, only one inhibitor that specifically blocks bitter receptor activation has been described. Here, we describe a new inhibitor of bitter taste receptors, p-(dipropylsulfamoylbenzoic acid (probenecid, that acts on a subset of TAS2Rs and inhibits through a novel, allosteric mechanism of action. Probenecid is an FDA-approved inhibitor of the Multidrug Resistance Protein 1 (MRP1 transporter and is clinically used to treat gout in humans. Probenecid is also commonly used to enhance cellular signals in GPCR calcium mobilization assays. We show that probenecid specifically inhibits the cellular response mediated by the bitter taste receptor hTAS2R16 and provide molecular and pharmacological evidence for direct interaction with this GPCR using a non-competitive (allosteric mechanism. Through a comprehensive analysis of hTAS2R16 point mutants, we define amino acid residues involved in the probenecid interaction that result in decreased sensitivity to probenecid while maintaining normal responses to salicin. Probenecid inhibits hTAS2R16, hTAS2R38, and hTAS2R43, but does not inhibit the bitter receptor hTAS2R31 or non-TAS2R GPCRs. Additionally, structurally unrelated MRP1 inhibitors, such as indomethacin, fail to inhibit hTAS2R16 function. Finally, we demonstrate that the inhibitory activity of probenecid in cellular experiments translates to inhibition of bitter taste perception of salicin in humans. This work identifies probenecid as a pharmacological tool for understanding the cell

  7. Involvement of dopamine receptors within the dorsal hippocampus in suppression of the formalin-induced orofacial pain.

    Science.gov (United States)

    Shamsizadeh, Ali; Pahlevani, Pouyan; Haghparast, Amir; Moslehi, Maryam; Zarepour, Leila; Haghparast, Abbas

    2013-12-01

    It is widely established that the dopaminergic system has profound effects on pain modulation in different regions of the brain including the hippocampus, the salient area for brain functions. The orofacial region is one of the most densely innervated (by the trigeminal nerves) areas of the body susceptible to acute and chronic pains. In this study, we tried to examine the effects of dopamine receptors located in the dorsal hippocampus (CA1) region upon the modulation of orofacial pain induced by the formalin test. To induce orofacial pain in male Wistar rats, 50μl of 1% formalin was subcutaneously injected into the upper lip. In control and experimental groups, two guide cannulae were stereotaxically implanted in the CA1, and SKF-38393 (0.25, 0.5, 1 and 2μg/0.5μl saline) as a D1-like receptor agonist, SCH-23390 (1μg/0.5μl saline) as a D1-like receptor antagonist, Quinpirole (0.5, 1, 2 and 4μg/0.5μl saline) as a D2-like receptor agonist and Sulpiride(3μg/0.5μl DMSO) as a D2-like receptor antagonist or vehicles were microinjected. For induction of orofacial pain, 50μl of 1% formalin was subcutaneously injected into the left side of the upper lip. Results indicated that SKF-38393 at the dose of 1 and 2μg significantly reduced pain during the first and second phases of observed pain while SCH-23390 reversed such analgesic effect. Moreover, there is a significant difference between groups in which animals received 2 and 4μg quinpirole or vehicle in the first phase (early phase) of pain. The three high doses of this compound (1, 2 and 4μg) appeared to have an analgesic effect during the second (late) phase. Furthermore, Sulpiride could potentially reverse the observed analgesic effects already induced by an agonist. Current findings suggest that the dorsal hippocampal dopamine receptors exert an analgesic effect during the orofacial pain test. Copyright © 2013 Elsevier Inc. All rights reserved.

  8. The nonsteroidal mycoestrogen zearalenone and its five metabolites suppress LH secretion from the bovine anterior pituitary cells via the estradiol receptor GPR30 in vitro.

    Science.gov (United States)

    Nakamura, Urara; Kadokawa, Hiroya

    2015-11-01

    Picomolar concentrations of estradiol produce nongenomic suppression of GnRH-induced LH secretion from the anterior pituitary (AP) of cattle via G-protein-coupled receptor 30 (GPR30). Zearalenone (ZEN) is the nonsteroidal mycoestrogen produced by Fusarium fungi and has been detected in cereal grains, animal feed, and ruminant urine worldwide. Zearalenone has a prolonged blood half-life that results from enterohepatic cycling. There are five metabolites of ZEN: α-zearalanol (α-ZAL), β-zearalanol (β-ZAL), α-zearalenol (α-ZOL), β-zearalenol (β-ZOL), and zearalanone, which may persist for long periods in animals and humans after consumption of ZEN-contaminated feed. We recently reported that GPR30 bound with α-ZAL decreases cytoplasmic cAMP but not gene expression of LHα and LHβ subunits, and GPR30 bound with α-ZAL suppresses GnRH-induced LH release in bovine AP cells in vitro. We tested the hypothesis that GPR30 bound with ZEN or one of the four previously untested metabolites suppresses GnRH-induced LH release from the bovine AP cells in vitro. Anterior pituitary cells were cultured for 3 days under steroid-free conditions and were then incubated with various concentrations (0.001-10 nM) of estradiol or one of the ZEN analogs for 5 minutes before GnRH stimulation. Gonadotropin-releasing hormone-stimulated LH secretion from AP cells was inhibited by all of the test concentrations of ZEN, 0.001 to 1 nM of α-ZAL, and 0.001 to 0.1 nM of the remaining four analogs. Pretreatment for 5 minutes with a GPR30-specific antagonist, G36, inhibited estradiol- and the ZEN analog-induced suppression of LH secretion from cultured AP cells. G36 alone had no significant effect on LH secretion. The estimated order of the nongenomic inhibiting effect was ZEN, α-ZAL, zearalanone, α-ZOL, β-ZOL, and β-ZAL, which is quite different from the reported order for their genomic effects. Therefore, ZEN and all of its metabolites suppress LH secretion from the bovine AP

  9. Losartan attenuated lipopolysaccharide-induced lung injury by suppression of lectin-like oxidized low-density lipoprotein receptor-1.

    Science.gov (United States)

    Deng, Wang; Deng, Yue; Deng, Jia; Wang, Dao-Xin; Zhang, Ting

    2015-01-01

    Recent study has shown that renin-angiotensin system plays an important role in the development of acute lung injury (ALI) with high level of angiotensin II (AngII) generated form AngI catalyzed by angiotensin-converting enzyme. AngII plays a major effect mainly through AT1 receptor. Therefore, we speculate inhibition of AT1 receptor may possibly attenuate the lung injury. Losartan, an antagonist of AT1 receptor for angiotensin II, attenuated lung injury by alleviation of the inflammation response in ALI, but the mechanism of losartan in ALI still remains unclear. Thirty male Sprague-Dawley rats were randomly divided into Control group, ALI group (LPS), and Losartan group (LPS + Losartan). Bronchoalveolar lavage fluid (BALF) and lung tissue were obtained for analysis. The expressions of lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1), intercellular adhesion molecule-1 (ICAM-1) and caspase-3 were detected by reverse transcriptase polymerase chain reaction (RT-PCR) and western blotting. In ALI group, TNF-α and protein level in BALF, MPO activity in lung tissue, pulmonary edema and lung injury were significantly increased. Losartan significantly reduced LPS-induced increase in TNF-α and protein level in BALF, MPO activity, pulmonary edema and lung injury in LPS-induced lung injury. The mRNA and protein expression levels of LOX-1 were significantly decreased with the administration of losartan in LPS-induced lung injury. Also, losartan blocked the protein levels of caspase-3 and ICAM-1 mediated by LOX-1 in LPS-induced lung injury. Losartan attenuated lung injury by alleviation of the inflammation and cell apoptosis by inhibition of LOX-1 in LPS-induced lung injury.

  10. Lubiprostone prevents nonsteroidal anti-inflammatory drug-induced small intestinal damage by suppressing the expression of inflammatory mediators via EP4 receptors.

    Science.gov (United States)

    Hayashi, Shusaku; Kurata, Naoto; Yamaguchi, Aya; Amagase, Kikuko; Takeuchi, Koji

    2014-06-01

    Lubiprostone, a bicyclic fatty acid derived from prostaglandin E1, has been used to treat chronic constipation and irritable bowel syndrome, and its mechanism of action has been attributed to the stimulation of intestinal fluid secretion via the activation of the chloride channel protein 2/cystic fibrosis transmembrane regulator (ClC-2/CFTR) chloride channels. We examined the effects of lubiprostone on indomethacin-induced enteropathy and investigated the functional mechanisms involved, including its relationship with the EP4 receptor subtype. Male Sprague-Dawley rats were administered indomethacin (10 mg/kg p.o.) and killed 24 hours later to examine the hemorrhagic lesions that developed in the small intestine. Lubiprostone (0.01-1 mg/kg) was administered orally twice 30 minutes before and 9 h after the indomethacin treatment. Indomethacin markedly damaged the small intestine, accompanied by intestinal hypermotility, a decrease in mucus and fluid secretion, and an increase in enterobacterial invasion as well as the up-regulation of inducible nitric-oxide synthase (iNOS) and tumor necrosis factor α (TNFα) mRNAs. Lubiprostone significantly reduced the severity of these lesions, with the concomitant suppression of the functional changes. The effects of lubiprostone on the intestinal lesions and functional alterations were significantly abrogated by the coadministration of AE3-208 [4-(4-cyano-2-(2-(4-fluoronaphthalen-1-yl)propionylamino)phenyl)butyric acid], a selective EP4 antagonist, but not by CFTR(inh)-172, a CFTR inhibitor. These results suggest that lubiprostone may prevent indomethacin-induced enteropathy via an EP4 receptor-dependent mechanism. This effect may be functionally associated with the inhibition of intestinal hypermotility and increase in mucus/fluid secretion, resulting in the suppression of bacterial invasion and iNOS/TNFα expression, which are major pathogenic events in enteropathy. The direct activation of CFTR/ClC-2 chloride channels is not

  11. Inhibition of LPS binding to MD-2 co-receptor for suppressing TLR4-mediated expression of inflammatory cytokine by 1-dehydro-10-gingerdione from dietary ginger

    Energy Technology Data Exchange (ETDEWEB)

    Park, Sun Hong; Kyeong, Min Sik; Hwang, Yuri [College of Pharmacy, Chungbuk National University, Cheongju 361-763 (Korea, Republic of); Ryu, Shi Yong [Korea Research Institute of Chemical Technology, Daejeon 305-600 (Korea, Republic of); Han, Sang-Bae [College of Pharmacy, Chungbuk National University, Cheongju 361-763 (Korea, Republic of); Kim, Youngsoo, E-mail: youngsoo@chungbuk.ac.kr [College of Pharmacy, Chungbuk National University, Cheongju 361-763 (Korea, Republic of)

    2012-03-23

    Highlights: Black-Right-Pointing-Pointer 1-Dehydro-10-gingerdione (1D10G) from ginger inhibits LPS binding to MD-2. Black-Right-Pointing-Pointer 1D10G suppresses MyD88- or TRIF-dependent signaling in LPS-activated macrophages. Black-Right-Pointing-Pointer 1D10G down-regulates the expression of NF-{kappa}B-, AP1- or IRF3-target genes. Black-Right-Pointing-Pointer MD-2 is a molecular target in the anti-inflammatory action of 1D10G. -- Abstract: Myeloid differentiation protein 2 (MD-2) is a co-receptor of toll-like receptor 4 (TLR4) for innate immunity. Here, we delineated a new mechanism of 1-dehydro-10-gingerdione (1D10G), one of pungent isolates from ginger (Zingiber officinale), in the suppression of lipopolysaccharide (LPS)-induced gene expression of inflammatory cytokines. 1D10G inhibited LPS binding to MD-2 with higher affinity than gingerol and shogaol from dietary ginger. Moreover, 1D10G down-regulated TLR4-mediated expression of nuclear factor-{kappa}B (NF-{kappa}B) or activating protein 1 (AP1)-target genes such as tumor necrosis factor {alpha} (TNF-{alpha}) and interleukin-1{beta}, as well as those of interferon (IFN) regulatory factor 3 (IRF3)-target IFN-{beta} gene and IFN-{gamma} inducible protein 10 (IP-10) in LPS-activated macrophages. Taken together, MD-2 is a molecular target in the anti-inflammatory action of 1D10G.

  12. Urolithin A suppresses the proliferation of endometrial cancer cells by mediating estrogen receptor-α-dependent gene expression.

    Science.gov (United States)

    Zhang, Wei; Chen, Jo-Hsin; Aguilera-Barrantes, Irene; Shiau, Chung-Wai; Sheng, Xiugui; Wang, Li-Shu; Stoner, Gary D; Huang, Yi-Wen

    2016-11-01

    Obese and overweight women are at high risk of developing endometrial cancer; indeed, many of endometrial cancer patients are obese. The increased number and size of adipocytes due to obesity elevate levels of circulating estrogens that stimulate cell proliferation in the endometrium. However, black raspberries are a promising approach to preventing endometrial cancer. We examined 17 black raspberry constituents and metabolites (10 μM or 10 μg/mL, 48 h) for their ability to prevent endometrial cancer cells from proliferating. Urolithin A (UA) was most able to suppress proliferation in a time- and dose-dependent manner (p endometrial cancer cells. UA enhanced the expression of ERβ, PGR, pS2, GREB1 while inhibiting the expression of ERα and GRIP1. Coincubating UA-treated cells with the estrogen antagonist ICI182,780 abolished UA's estrogenic effects. Knocking down ERα suppressed PGR, pS2, and GREB gene expression but increased GRIP1 expression. Thus, UA's actions appear to be mediated through ERα. This study suggests that UA modulates ERα-dependent gene expression, thereby inhibiting endometrial cancer proliferation. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Arctigenin suppresses receptor activator of nuclear factor κB ligand (RANKL)-mediated osteoclast differentiation in bone marrow-derived macrophages.

    Science.gov (United States)

    Kim, A-Ram; Kim, Hyuk Soon; Lee, Jeong Min; Choi, Jung Ho; Kim, Se Na; Kim, Do Kyun; Kim, Ji Hyung; Mun, Se Hwan; Kim, Jie Wan; Jeon, Hyun Soo; Kim, Young Mi; Choi, Wahn Soo

    2012-05-05

    Osteoclasts, multinucleated bone-resorbing cells, are closely associated with bone diseases such as rheumatoid arthritis and osteoporosis. Osteoclasts are derived from hematopoietic precursor cells, and their differentiation is mediated by two cytokines, including macrophage colony stimulating factor and receptor activator of nuclear factor κB ligand (RANKL). Previous studies have shown that arctigenin exhibits an anti-inflammatory effect. However, the effect of arctigenin on osteoclast differentiation is yet to be elucidated. In this study, we found that arctigenin inhibited RANKL-mediated osteoclast differentiation in bone marrow macrophages in a dose-dependent manner and suppressed RANKL-mediated bone resorption. Additionally, the expression of typical marker proteins, such as NFATc1, c-Fos, TRAF6, c-Src, and cathepsin K, were significantly inhibited. Arctigenin inhibited the phosphorylation of Erk1/2, but not p38 and JNK, in a dose-dependent manner. Arctigenin also dramatically suppressed immunoreceptor tyrosine-based activation motif-mediated costimulatory signaling molecules, including Syk and PLCγ2, and Gab2. Notably, arctigenin inhibited the activation of Syk through RANKL stimulation. Furthermore, arctigenin prevented osteoclast differentiation in the calvarial bone of mice following stimulation with lipopolysaccharide. Our results show that arctigenin inhibits osteoclast differentiation in vitro and in vivo. Therefore, arctigenin may be useful for treating rheumatoid arthritis and osteoporosis. Copyright © 2012 Elsevier B.V. All rights reserved.

  14. Mangiferin inhibits lipopolysaccharide-induced production of interleukin-6 in human oral epithelial cells by suppressing toll-like receptor signaling.

    Science.gov (United States)

    Li, Hao; Wang, Qi; Chen, Xinmin; Ding, Yi; Li, Wei

    2016-11-01

    Oral epithelial cells have currently been found to play an important role in inflammatory modulation in periodontitis. Mangiferin is a natural glucosylxanthone with anti-inflammatory activity. The aim of this study was to investigate the regulatory effect of mangiferin on lipopolysaccharide (LPS)-induced production of proinflammatory cytokine interleukin-6 (IL-6) in oral epithelial cells and the underlying mechanisms. The levels of LPS-induced IL-6 production in OKF6/TERT-2 oral keratinocytes were detected using enzyme-linked immunosorbent assay (ELISA). The expression of Toll-like receptor (TLR) 2 and TLR4 was determined using western blot analysis. And the phosphorylation of TLR downstream nuclear factor-κB (NF-κB), p38 mitogen-activated protein kinase (p38 MAPK) and c-Jun N-terminal kinase (JNK) was examined using cell-based protein phosphorylation ELISA kits. We found that mangiferin reduced LPS-upregulated IL-6 production in OKF6/TERT-2 cells. Additionally, mangiferin inhibited LPS-induced TLR2 and TLR4 overexpression, and suppressed the phosphorylation of NF-κB, p38 MAPK and JNK. Moreover, mangiferin repressed IL-6 production and TLR signaling activation in a dose-dependent manner after 24h treatment. Mangiferin decreases LPS-induced production of IL-6 in human oral epithelial cells by suppressing TLR signaling, and this glucosylxanthone may have potential for the treatment of periodontitis. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Low-concentration heparin suppresses ionomycin-activated CAMK-II/EGF receptor- and ERK-mediated signaling in mesangial cells.

    Science.gov (United States)

    Song, Lifang; Xiao, Weiqun; Templeton, Douglas M

    2010-08-01

    Heparin and endogenous heparinoids inhibit the proliferation of smooth muscle cells, including renal mesangial cells; multiple effects on signaling pathways are well established, including effects on PKC, Erk, and CaMK-II. Many studies have used heparin at concentrations of 100 microg/ml or higher, whereas endogenous concentrations of heparinoids are much lower. Here we report the effects of low-concentration (1 microg/ml) heparin on activation of several kinases and subsequent induction of the c-fos gene in mesangial cells in response to the calcium ionophore, ionomycin, in the absence of serum factors. Ionomycin rapidly increases the phosphorylation of CaMK-II (by 30 s), and subsequently of the EGF receptor (EGFR), c-Src, and Erk 1/2. Low-dose heparin suppresses the ionomycin-dependent phosphorylation of EGFR, c-Src, and Erk 1/2, but not of CaMK-II, whereas inhibition of activated CaMK-II reduces phosphorylation of EGFR, c-Src, and Erk. Our data support a mechanism whereby heparin acts at the cell surface to suppress downstream targets of CaMK-II, including EGFR, leading in turn to a decrease in Erk- (but not c-Src-) dependent induction of c-fos.

  16. Preseasonal prophylactic treatment with antihistamines suppresses nasal symptoms and expression of histamine H₁ receptor mRNA in the nasal mucosa of patients with pollinosis.

    Science.gov (United States)

    Mizuguchi, H; Kitamura, Y; Kondo, Y; Kuroda, W; Yoshida, H; Miyamoto, Y; Hattori, M; Fukui, H; Takeda, N

    2010-12-01

    Administration of antihistamines 2-4 weeks before the pollen season showed a greater inhibitory effect on nasal allergy symptoms in patients with seasonal allergic rhinitis. However, the mechanism of slow-onset effects of preseasonal treatment with antihistamines remains unclear. Here, we investigated the effect of preseasonal prophylactic treatment with antihistamines on nasal symptoms and the expression of histamine H₁ receptor (H1R) mRNA of the nasal mucosa in patients with cedar pollen pollinosis. During the peak pollen period, the expression of H1R mRNA in the nasal mucosa and the scores of sneezing and watery rhinorrhea in patients receiving preseasonal prophylactic treatment with antihistamines were significantly suppressed in comparison with those in the patients without treatment. Moreover, there was a significant correlation between the nasal symptoms and the expression of H1R mRNA in both patients with or without preseasonal prophylactic treatment. These findings suggest that preseasonal prophylactic treatment with antihistamines is more effective than on-seasonal administration to patients with pollinosis in reducing nasal symptoms during the peak pollen period by suppressing H1R gene expression in the nasal mucosa. Copyright 2010 Prous Science, S.A.U. or its licensors. All rights reserved.

  17. Androgen-androgen receptor system improves chronic inflammatory conditions by suppressing monocyte chemoattractant protein-1 gene expression in adipocytes via transcriptional regulation

    Energy Technology Data Exchange (ETDEWEB)

    Morooka, Nobukatsu, E-mail: amorooka@gunma-u.ac.jp [Institute for Molecular and Cellular Regulation, Gunma University, 3-39-15 Showa-machi, Maebashi, Gunma, 371-8512 (Japan); Ueguri, Kei [Institute for Molecular and Cellular Regulation, Gunma University, 3-39-15 Showa-machi, Maebashi, Gunma, 371-8512 (Japan); Yee, Karen Kar Lye [Institute for Molecular and Cellular Regulation, Gunma University, 3-39-15 Showa-machi, Maebashi, Gunma, 371-8512 (Japan); Human Resources Cultivation Center, Gunma University, 1-5-1 Tenjin-cho, Kiryushi, Gunma, 376-8515 (Japan); Yanase, Toshihiko [Department of Endocrinology and Diabetes Mellitus, School of Medicine, Fukuoka University, Jonan-ku, Fukuoka, 814-0180 (Japan); Sato, Takashi [Institute for Molecular and Cellular Regulation, Gunma University, 3-39-15 Showa-machi, Maebashi, Gunma, 371-8512 (Japan)

    2016-09-02

    Age-related decreases in sex hormones are closely related to chronic inflammation in obesity and metabolic diseases. Particularly, the molecular basis of androgen activity in regulating inflammation and controlling metabolism remains largely unknown. Obese adipocytes secrete monocyte chemoattractant protein-1 (MCP-1), a key chemokine that promotes the infiltration of monocytes/macrophages into adipose tissue, thereby leading to metabolic disorders. Here, we studied the role of androgen-androgen receptor (AR) action in regulating MCP-1 expression in adipose tissue. We observed the induction of Mcp-1 expression in 3T3-L1 adipocytes co-cultured with RAW264.7 macrophages. Additionally, Mcp-1 expression was upregulated by culturing in conditioned medium derived from inflammatory macrophages (M1-Mφ) containing tumor necrosis factor-alpha (TNF-α). We found that sex hormones downregulated TNF-α-induced Mcp-1 and interleukin (Il)-6 expression in 3T3-L1 adipocytes. Furthermore, luciferase-reporter analysis indicated that MCP-1 promoter activity was predominantly suppressed by dihydrotestosterone (DHT)-AR interactions through functional canonical nuclear factor-kappa B (NF-κB) sites, whereas non-canonical NF-κB site containing important flanking sequences exhibited minor contributions to DHT-AR transcriptional repression. These findings suggested that androgen-AR suppressed obesity-induced chronic inflammation in adipose tissue. - Highlights: • DHT, non-aromatizable androgen suppresses Mcp-1 expression in adipocytes. • Mcp-1 transcription was negatively regulated by DHT-AR action. • DHT-AR selectively regulates Mcp-1 transcription through distinct NF-κB sites.

  18. Cisplatin targets the stromal cell-derived factor-1-CXC chemokine receptor type 4 axis to suppress metastasis and invasion of ovarian cancer-initiating cells.

    Science.gov (United States)

    Yu, Zhi-hua; Liu, Te; Zhao, Yan-hui; Huang, Yong-yi; Gao, Yong-tao

    2014-05-01

    In ovarian cancer, CD44+/CD117+ stem cells, also known as cancer-initiating cells (CICs), are highly proliferative and invasive. Therefore, the CD44+/CD117+ subpopulation is thought to be an important target for novel therapeutic strategies. In this study, we investigated the effects of cisplatin (CDDP) on metastasis and invasion suppression of ovarian CICs by targeting the CXC chemokine receptor-4 (CXCR4) signaling pathway in vitro and in vivo. CD44+/CD117+ ovarian CICs were enriched from human primary ovarian tumor tissues and confirmed by flow cytometry sorting. A 3-(4,5-dimethylthiazol-2-yl)-2.5-dipheny-tetrazolium bromide (MTT) assay revealed significant inhibition of proliferation of ovarian CICs with increasing CDDP drug concentrations. Moreover, colony formation and transwell migration assays indicated that CDDP significantly suppressed the invasive capacity of ovarian CICs in vitro. The expression levels of stromal cell-derived factor (SDF)-1, CXCR4, matrix metalloproteinase (MMP) 2, and MMP9 mRNA and protein levels were significantly reduced in CDDP-treated cells compared to untreated ovarian CICs. Furthermore, xenograft experiments confirmed that CDDP suppressed the growth of xenograft tumors formed by ovarian CICs in vivo. In addition, CXCR4 agonist (diprotin A) treatment of ovarian CICs weakened the effects of CDDP and enhanced SDF-1-CXCR4 axis expression in ovarian CICs. Thus, the SDF-1-CXCR4 axis is an important mediator of proliferation and invasion in CXCR4-overexpressing ovarian cancer-initiating cells (OCICs). Furthermore, CDDP inhibits invasion and metastasis of OCICs by targeting SDF-1-CXCR4 axis expression.

  19. Klotho-beta overexpression as a novel target for suppressing proliferation and fibroblast growth factor receptor-4 signaling in hepatocellular carcinoma

    Directory of Open Access Journals (Sweden)

    Poh Weijie

    2012-03-01

    Full Text Available Abstract Background We had previously demonstrated overexpression of fibroblast growth factor receptor-4 (FGFR4 in hepatocellular carcinoma (HCC. However, additional molecular mechanisms resulting in amplified FGFR4 signaling in HCC remain under-studied. Here, we studied the mechanistic role of its co-receptor klotho-beta (KLB in driving elevated FGFR4 activity in HCC progression. Results Quantitative real-time PCR analysis identified frequent elevation of KLB gene expression in HCC tumors relative to matched non-tumor tissue, with a more than two-fold increase correlating with development of multiple tumors in patients. KLB-silencing in Huh7 cells decreased cell proliferation and suppressed FGFR4 downstream signaling. While transient repression of KLB-FGFR4 signaling decreased protein expression of alpha-fetoprotein (AFP, a HCC diagnostic marker, prolonged inhibition enriched for resistant HCC cells exhibiting increased liver stemness. Conclusions Elevated KLB expression in HCC tissues provides further credence to the oncogenic role of increased FGFR4 signaling in HCC progression and represents a novel biomarker to identify additional patients amenable to anti-FGFR4 therapy. The restricted tissue expression profile of KLB, together with the anti-proliferative effect observed with KLB-silencing, also qualifies it as a specific and potent therapeutic target for HCC patients. The enrichment of a liver stem cell-like population in response to extended KLB-FGFR4 repression necessitates further investigation to target the development of drug resistance.

  20. The aqueous extract of Brucea javanica suppresses cell growth and alleviates tumorigenesis of human lung cancer cells by targeting mutated epidermal growth factor receptor

    Directory of Open Access Journals (Sweden)

    Kim SH

    2016-11-01

    Full Text Available Seung-Hun Kim,1,* Chun-Yen Liu,1,* Po-Wei Fan,1 Chang-Heng Hsieh,1 Hsuan-Yuan Lin,1 Ming-Chung Lee,2 Kang Fang1 1Department of Life Science, National Taiwan Normal University, Taipei, 2Brion Research Institute of Taiwan, New Taipei City, Taiwan *These authors contributed equally to this work Abstract: As a practical and safe herbal medicine, the seeds of Brucea javanica (L. Merr., were used to cure patients suffering from infectious diseases such as malaria. Recent advances revealed that the herb could also be a useful cancer therapy agent. The study demonstrated that aqueous B. javanica (BJ extract attenuated the growth of human non-small-lung cancer cells bearing mutant L858R/T790M epidermal growth factor receptor (EGFR. The reduced cell viability in H1975 cells was attributed to apoptosis. Transfection of EGFR small hairpin RNA reverted the sensitivities. When nude mice were fed BJ extract, the growth of xenograft tumors, as established by H1975 cells, was suppressed. Additional histological examination and fluorescence analysis of the resected tissues proved that the induced apoptosis mitigated tumor growth. The work proved that the BJ extract exerted its effectiveness by targeting lung cancer cells carrying mutated EGFR while alleviating tumorigenesis. Aqueous BJ extract is a good candidate to overcome drug resistance in patients undergoing target therapy. Keywords: Brucea javanica, target therapy, epidermal growth factor receptor, human lung, herbal medicine, apoptosis

  1. Loss of α1,6-fucosyltransferase suppressed liver regeneration: implication of core fucose in the regulation of growth factor receptor-mediated cellular signaling.

    Science.gov (United States)

    Wang, Yuqin; Fukuda, Tomohiko; Isaji, Tomoya; Lu, Jishun; Gu, Wei; Lee, Ho-Hsun; Ohkubo, Yasuhito; Kamada, Yoshihiro; Taniguchi, Naoyuki; Miyoshi, Eiji; Gu, Jianguo

    2015-02-05

    Core fucosylation is an important post-translational modification, which is catalyzed by α1,6-fucosyltransferase (Fut8). Increased expression of Fut8 has been shown in diverse carcinomas including hepatocarcinoma. In this study, we investigated the role of Fut8 expression in liver regeneration by using the 70% partial hepatectomy (PH) model, and found that Fut8 is also critical for the regeneration of liver. Interestingly, we show that the Fut8 activities were significantly increased in the beginning of PH (~4d), but returned to the basal level in the late stage of PH. Lacking Fut8 led to delayed liver recovery in mice. This retardation mainly resulted from suppressed hepatocyte proliferation, as supported not only by a decreased phosphorylation level of epidermal growth factor (EGF) receptor and hepatocyte growth factor (HGF) receptor in the liver of Fut8(-/-) mice in vivo, but by the reduced response to exogenous EGF and HGF of the primary hepatocytes isolated from the Fut8(-/-) mice. Furthermore, an administration of L-fucose, which can increase GDP-fucose synthesis through a salvage pathway, significantly rescued the delayed liver regeneration of Fut8(+/-) mice. Overall, our study provides the first direct evidence for the involvement of Fut8 in liver regeneration.

  2. Docosahexanoic acid modifies low-density lipoprotein receptor abundance in HepG2 cells via suppression of the LXRα-Idol pathway.

    Science.gov (United States)

    Zhou, Ying; Guo, Yue; Zhuang, Xiaodong; Du, Zhimin

    2015-03-01

    As a daily supplement, omega‑3 fatty acid is confirmed to be of benefit in hypertriglyceridemia. However, the effect of omega‑3 fatty acids on the low‑density lipoprotein cholesterol (LDL‑C) metabolism remains a controversial issue. In this study, we focused on the regulatory effect of docosahexanoic acid (DHA), one type of omega‑3 fatty acid, exerted on the LDL receptor (LDLR), a determinant regulator of the LDL‑C metabolism, and explored the potential mechanism. We observed that DHA increased hepatic LDLR protein in the presence of 25‑hydroxycholesterol in HepG2 cells but did not alter the mRNA level. Previous studies have identified inducible degrader of the LDLR (Idol) as a novel negative post‑translational modulator of LDLR and a direct transcriptional target of liver X receptor α (LXRα). Since DHA had no effect on the transcriptional level of LDLR, we speculated that the post‑transcriptional pathway LXRα‑Idol participated in this regulation. The results reveal that DHA downregulated the expression of LXRα and Idol in coordination with the upregulation of LDLR expression. Multiple mechanisms are involved in the regulation of LDLR by DHA, and the suppression of the LXRα‑Idol pathway is one of these mechanisms.

  3. Role of the aryl hydrocarbon receptor and Cyp1b1 in the antiestrogenic activity of 2,3,7,8-tetrachlorodibenzo-p-dioxin

    Energy Technology Data Exchange (ETDEWEB)

    Takemoto, Kei; Nakajima, Miki; Fujiki, Yuto; Katoh, Miki; Yokoi, Tsuyoshi [Division of Drug Metabolism, Faculty of Pharmaceutical Sciences, Kanazawa University, Takara-machi 13-1, 920-0934, Kanazawa (Japan); Gonzalez, Frank J. [National Cancer Institute, MD 20892, Bethesda (United States)

    2004-06-01

    The role of aryl hydrocarbon receptor (AhR) and cytochrome P450 (Cyp) 1 family in the antiestrogenic activity of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) was investigated in vivo. Immature (21 days old) AhR, Cyp1a2, or Cyp1b1 knockout (-/-) mice were treated intraperitoneally with estradiol (E2, 20 ng/mouse per day, for 14 consecutive days) and/or TCDD (200 ng/mouse per day, on days 7, 9, 11, and 13). Uterine wet weight and uterine peroxidase activity (UPA) were measured as markers of estrogen responsiveness. UPA was a better marker of estrogen responsiveness than the uterine wet weight. In AhR wild-type (+/+) mice, UPA (208.1{+-}81.6 units/g tissue) was increased by the administration of E2 (to 297.2{+-}178.7 units/g). The administration of TCDD significantly (p<0.01) decreased the UPA (10.5{+-}3.4 units/g) compared with that in the control mice. Co-administration of TCDD with E2 also significantly (p<0.05) decreased the UPA (18.8{+-}19.9 units/g) compared with that in E2-treated mice. In AhR(-/-) mice, UPA (162.9{+-}146.7 units/g) was significantly (p<0.01) increased by the administration of E2 (486.8{+-}108.2 units/g). In contrast to the results in AhR(+/+) mice, UPA was not affected by the administration of TCDD (51.8{+-}70.6 units/g) compared with control, and co-administration of TCDD with E2 (545.8{+-}189.4 units/g) compared with that in E2-treated mice. In Cyp1a2/1b1(+/+) mice, UPA was significantly (p<0.05) increased by the administration of E2 (70.0{+-}36.4 units/g). Co-administration of TCDD with E2 significantly (p<0.05) decreased the UPA (29.6{+-}22.2 units/g) compared with that in E2-treated mice. In Cyp1a2(-/-) mice, co-administration of TCDD with E2 significantly (p<0.01) decreased the UPA (6.8{+-}5.1 units/g) compared with that in E2-treated mice. In Cyp1b1(-/-) mice, UPA (5.5{+-}8.1 units/g) was significantly (p<0.05) increased by the administration of E2 (56.6{+-}34.1 units/g). In contrast to the results in Cyp1a2/1b1(+/+) mice or Cyp1a2

  4. μ opioid receptor activation hyperpolarizes respiratory-controlling Kölliker-Fuse neurons and suppresses post-inspiratory drive.

    Science.gov (United States)

    Levitt, Erica S; Abdala, Ana P; Paton, Julian F R; Bissonnette, John M; Williams, John T

    2015-10-01

    In addition to reductions in respiratory rate, opioids also cause aspiration and difficulty swallowing, indicating impairment of the upper airways. The Kölliker-Fuse (KF) maintains upper airway patency and a normal respiratory pattern. In this study, activation of μ opioid receptors in the KF reduced respiratory frequency and tidal volume in anaesthetized rats. Nerve recordings in an in situ preparation showed that activation of μ opioid receptors in the KF eliminated the post-inspiration phase of the respiratory cycle. In brain slices, μ opioid agonists hyperpolarized a distinct population (61%) of KF neurons by activation of an inwardly rectifying potassium conductance. These results suggest that KF neurons that are hyperpolarized by opioids could contribute to opioid-induced respiratory disturbances, particularly the impairment of upper airways. Opioid-induced respiratory effects include aspiration and difficulty swallowing, suggesting impairment of the upper airways. The pontine Kölliker-Fuse nucleus (KF) controls upper airway patency and regulates respiration, in particular the inspiratory/expiratory phase transition. Given the importance of the KF in coordinating respiratory pattern, the mechanisms of μ opioid receptor activation in this nucleus were investigated at the systems and cellular level. In anaesthetized, vagi-intact rats, injection of opioid agonists DAMGO or [Met(5) ]enkephalin (ME) into the KF reduced respiratory frequency and amplitude. The μ opioid agonist DAMGO applied directly into the KF of the in situ arterially perfused working heart-brainstem preparation of rat resulted in robust apneusis (lengthened low amplitude inspiration due to loss of post-inspiratory drive) that was rapidly reversed by the opioid antagonist naloxone. In brain slice preparations, activation of μ opioid receptors on KF neurons hyperpolarized a distinct population (61%) of neurons. As expected, the opioid-induced hyperpolarization reduced the excitability of

  5. Bovine Immunoinhibitory Receptors Contribute to Suppression of Mycobacterium avium subsp. paratuberculosis-Specific T-Cell Responses.

    Science.gov (United States)

    Okagawa, Tomohiro; Konnai, Satoru; Nishimori, Asami; Ikebuchi, Ryoyo; Mizorogi, Seiko; Nagata, Reiko; Kawaji, Satoko; Tanaka, Shogo; Kagawa, Yumiko; Murata, Shiro; Mori, Yasuyuki; Ohashi, Kazuhiko

    2015-10-19

    Johne's disease (paratuberculosis) is a chronic enteritis in cattle that is caused by intracellular infection with Mycobacterium avium subsp. paratuberculosis. This infection is characterized by the functional exhaustion of T-cell responses to M. avium subsp. paratuberculosis antigens during late subclinical and clinical stages, presumably facilitating the persistence of this bacterium and the formation of clinical lesions. However, the mechanisms underlying T-cell exhaustion in Johne's disease are poorly understood. Thus, we performed expression and functional analyses of the immunoinhibitory molecules programmed death-1 (PD-1)/PD-ligand 1 (PD-L1) and lymphocyte activation gene 3 (LAG-3)/major histocompatibility complex class II (MHC-II) in M. avium subsp. paratuberculosis-infected cattle during the late subclinical stage. Flow cytometric analyses revealed the upregulation of PD-1 and LAG-3 in T cells in infected animals, which suffered progressive suppression of interferon gamma (IFN-γ) responses to the M. avium subsp. paratuberculosis antigen. In addition, PD-L1 and MHC-II were expressed on macrophages from infected animals, consistent with PD-1 and LAG-3 pathways contributing to the suppression of IFN-γ responses during the subclinical stages of M. avium subsp. paratuberculosis infection. Furthermore, dual blockade of PD-L1 and LAG-3 enhanced M. avium subsp. paratuberculosis-specific IFN-γ responses in blood from infected animals, and in vitro LAG-3 blockade enhanced IFN-γ production from M. avium subsp. paratuberculosis-specific CD4(+) and CD8(+) T cells. Taken together, the present data indicate that M. avium subsp. paratuberculosis-specific T-cell exhaustion is in part mediated by PD-1/PD-L1 and LAG-3/MHC-II interactions and that LAG-3 is a molecular target for the control of M. avium subsp. paratuberculosis-specific T-cell responses. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  6. Cannabinoid receptor agonism suppresses tremor, cognition disturbances and anxiety-like behaviors in a rat model of essential tremor.

    Science.gov (United States)

    Abbassian, Hassan; Esmaeili, Parisa; Tahamtan, Mahshid; Aghaei, Iraj; Vaziri, Zohreh; Sheibani, Vahid; Whalley, Benjamin J; Shabani, Mohammad

    2016-10-01

    Cognitive and motor disturbances are serious consequences of tremor induced by motor disorders. Despite a lack of effective clinical treatment, some potential therapeutic agents have been used to alleviate the cognitive symptoms in the animal models of tremor. In the current study, the effects of WIN55, 212-2 (WIN), a cannabinoid receptor (CBR) agonist, on harmaline-induced motor and cognitive impairments were studied. Adult rats were treated with WIN (0.5mg/kg; i.p.) 15min before harmaline administration (10mg/kg; ip) after which exploratory and anxiety related behaviors, and cognitive function were assessed using open-field behavior and shuttle box tests. Rats that received harmaline only exhibited a markedly reduced number of central square entries when compared to harmaline vehicle-treated controls, whereas those treated with WIN and harmaline showed a significant increase in central square entries, compared to harmaline only treated. The passive avoidance memory impairments observed in harmaline treated rats, was reversed somewhat by administration of WIN. The neuroprotective and anxiolytic effects of WIN demonstrated in the current study can be offered cannabinoid receptor (CBR) agonism as a potential neuroprotective agent in the treatment of patients with tremor that manifest mental dysfunctions. Copyright © 2016 Elsevier Inc. All rights reserved.

  7. Prenatal exposure to bisphenol-A is associated with Toll-like receptor-induced cytokine suppression in neonates.

    Science.gov (United States)

    Liao, Sui-Ling; Tsai, Ming-Han; Lai, Shen-Hao; Yao, Tsung-Chieh; Hua, Man-Chin; Yeh, Kuo-Wei; Chiang, Chi-Hsin; Huang, Shih-Yin; Huang, Jing-Long

    2016-03-01

    Despite widespread human exposure to biphenol A (BPA), limited studies exist on the association of BPA with adverse health outcomes in young children. This study aims to investigate the effect of prenatal exposure to BPA on toll-like receptor-induced cytokine responses in neonates and its association with infectious diseases later in life. Cord bloods were collected from 275 full-term neonates. Production of TNF-α, IL-6, and IL-10 were evaluated after stimulating mononuclear cells with toll-like receptor ligands (TLR1-4 and 7-8). Serum BPA concentrations were analyzed by enzyme-linked immunosorbent assay. Bacteria from nasopharyngeal specimens were identified with multiplex PCR and culture method. Result showed significant association between cord BPA concentration and TLR3- and TLR4-stimulated TNF-α response (P = 0.001) and that of TLR78-stimulated IL-6 response (P = 0.03). Clinical analysis did not show prenatal BPA exposure to be correlated with infection or bacterial colonization during the first year of life. This is the first cohort study that indicated prenatal BPA exposure to play a part in TLR-related innate immune response of neonatal infants. However, despite an altered immune homeostasis, result did not show such exposure to be associated with increased risk of infection during early infancy.

  8. Cytokines and Bone Loss in a 5-Year Longitudinal Study—Hormone Replacement Therapy Suppresses Serum Soluble Interleukin-6 Receptor and Increases Interleukin-1-Receptor Antagonist

    DEFF Research Database (Denmark)

    Abrahamsen, B.; Bonnevie-Nielsen, V.; Ebbesen, E.N.

    2000-01-01

    The proinflammatory cytokines interleukin-1 beta (IL-1 beta) and IL-6 may play a central role in the acceleration of postmenopausal bone loss, but observational studies have led to contradictory results. Estrogen-dependent changes in the production of IL-1 receptor antagonist (IL-1ra...... observed in the control group. IL-1ra was inversely correlated with bone loss at the ultradistal forearm (r = 0.29; p bone loss at the ultradistal forearm (r = 0.26; p ....05). High IL-6 levels were associated with slower bone loss (spine r = 0.31, p bone loss at the femoral neck (r = -0.29; p bone loss in the spine (r = -0...

  9. Activation of peroxisome proliferator-activated receptor-{alpha} (PPAR{alpha}) suppresses postprandial lipidemia through fatty acid oxidation in enterocytes

    Energy Technology Data Exchange (ETDEWEB)

    Kimura, Rino [Laboratory of Molecular Function of Food, Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Uji, Kyoto 611-0011 (Japan); Takahashi, Nobuyuki, E-mail: nobu@kais.kyoto-u.ac.jp [Laboratory of Molecular Function of Food, Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Uji, Kyoto 611-0011 (Japan); Murota, Kaeko [Department of Life Science, School of Science and Engineering, Kinki University, Osaka 770-8503 (Japan); Yamada, Yuko [Laboratory of Physiological Function of Food, Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Uji, Kyoto 611-0011 (Japan); Niiya, Saori; Kanzaki, Noriyuki; Murakami, Yoko [Laboratory of Molecular Function of Food, Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Uji, Kyoto 611-0011 (Japan); Moriyama, Tatsuya [Department of Applied Cell Biology, Graduate School of Agriculture, Kinki University, Nara 631-8505 (Japan); Goto, Tsuyoshi; Kawada, Teruo [Laboratory of Molecular Function of Food, Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Uji, Kyoto 611-0011 (Japan)

    2011-06-24

    Highlights: {yields} PPAR{alpha} activation increased mRNA expression levels of fatty acid oxidation-related genes in human intestinal epithelial Caco-2 cells. {yields} PPAR{alpha} activation also increased oxygen consumption rate and CO{sub 2} production and decreased secretion of triglyceride and ApoB from Caco-2 cells. {yields} Orally administration of bezafibrate increased mRNA expression levels of fatty acid oxidation-related genes and CO{sub 2} production in small intestinal epithelial cells. {yields} Treatment with bezafibrate decreased postprandial serum concentration of triglyceride after oral injection of olive oil in mice. {yields} It suggested that intestinal lipid metabolism regulated by PPAR{alpha} activation suppresses postprandial lipidemia. -- Abstract: Activation of peroxisome proliferator-activated receptor (PPAR)-{alpha} which regulates lipid metabolism in peripheral tissues such as the liver and skeletal muscle, decreases circulating lipid levels, thus improving hyperlipidemia under fasting conditions. Recently, postprandial serum lipid levels have been found to correlate more closely to cardiovascular diseases than fasting levels, although fasting hyperlipidemia is considered an important risk of cardiovascular diseases. However, the effect of PPAR{alpha} activation on postprandial lipidemia has not been clarified. In this study, we examined the effects of PPAR{alpha} activation in enterocytes on lipid secretion and postprandial lipidemia. In Caco-2 enterocytes, bezafibrate, a potent PPAR{alpha} agonist, increased mRNA expression levels of fatty acid oxidation-related genes, such as acyl-CoA oxidase, carnitine palmitoyl transferase, and acyl-CoA synthase, and oxygen consumption rate (OCR) and suppressed secretion levels of both triglycerides and apolipoprotein B into the basolateral side. In vivo experiments revealed that feeding high-fat-diet containing bezafibrate increased mRNA expression levels of fatty acid oxidation-related genes and

  10. Schistosome-derived omega-1 drives Th2 polarization by suppressing protein synthesis following internalization by the mannose receptor

    Science.gov (United States)

    Everts, Bart; Hussaarts, Leonie; Driessen, Nicole N.; Meevissen, Moniek H.J.; Schramm, Gabriele; van der Ham, Alwin J.; van der Hoeven, Barbara; Scholzen, Thomas; Burgdorf, Sven; Mohrs, Markus; Pearce, Edward J.; Hokke, Cornelis H.; Haas, Helmut; Smits, Hermelijn H.

    2012-01-01

    Omega-1, a glycosylated T2 ribonuclease (RNase) secreted by Schistosoma mansoni eggs and abundantly present in soluble egg antigen, has recently been shown to condition dendritic cells (DCs) to prime Th2 responses. However, the molecular mechanisms underlying this effect remain unknown. We show in this study by site-directed mutagenesis of omega-1 that both the glycosylation and the RNase activity are essential to condition DCs for Th2 polarization. Mechanistically, we demonstrate that omega-1 is bound and internalized via its glycans by the mannose receptor (MR) and subsequently impairs protein synthesis by degrading both ribosomal and messenger RNA. These experiments reveal an unrecognized pathway involving MR and interference with protein synthesis that conditions DCs for Th2 priming. PMID:22966004

  11. Pathway-selective suppression of chemokine receptor signaling in B cells by LPS through downregulation of PLC-β2

    Science.gov (United States)

    Shirakawa, Aiko-Konno; Liao, Fang; Zhang, Hongwei H; Hedrick, Michael N; Singh, Satya P; Wu, Dianqing; Farber, Joshua M

    2010-01-01

    Lymphocyte activation leads to changes in chemokine receptor expression. There are limited data, however, on how lymphocyte activators can alter chemokine signaling by affecting downstream pathways. We hypothesized that B cell-activating agents might alter chemokine responses by affecting downstream signal transducers, and that such effects might differ depending on the activator. We found that activating mouse B cells using either anti-IgM or lipopolysaccharide (LPS) increased the surface expression of CCR6 and CCR7 with large increases in chemotaxis to their cognate ligands. By contrast, while anti-IgM also led to enhanced calcium responses, LPS-treated cells showed only small changes in calcium signaling as compared with cells that were freshly isolated. Of particular interest, we found that LPS caused a reduction in the level of B-cell phospholipase C (PLC)-β2 mRNA and protein. Data obtained using PLC-β2−/− mice showed that the β2 isoform mediates close to one-half the chemokine-induced calcium signal in resting and anti-IgM-activated B cells, and we found that calcium signals in the LPS-treated cells were boosted by increasing the level of PLC-β2 using transfection, consistent with a functional effect of downregulating PLC-β2. Together, our results show activator-specific effects on responses through B-cell chemokine receptors that are mediated by quantitative changes in a downstream signal-transducing protein, revealing an activity for LPS as a downregulator of PLC-β2, and a novel mechanism for controlling chemokine-induced signals in lymphocytes. PMID:20871625

  12. The galanin-3 receptor antagonist, SNAP 37889, suppresses alcohol drinking and morphine self-administration in mice.

    Science.gov (United States)

    Scheller, Karlene J; Williams, Spencer J; Lawrence, Andrew J; Djouma, Elvan

    2017-05-15

    The neuropeptide, galanin, is widely expressed in the central and peripheral nervous systems and is involved in a range of different functions including nociception, neurogenesis, hormone release, reproduction, cognitive function and appetite. Given the overlap between galanin expression and reward circuitry in the brain, galanin has been targeted for alcohol use disorder (AUD) and opioid dependency. Furthermore, the galanin-3 receptor (GAL 3 ) specifically regulates emotional states and plays a role in motivation, reward and drug-seeking behaviour. We have previously shown that the GAL 3 antagonist, SNAP 37889, reduces ethanol self-administration and cue-induced re-instatement in alcohol-preferring (iP) rats with no alterations in locomotor activity or anxiety-like behaviour. The aim of this study was to investigate whether SNAP 37889 reduces binge drinking and/or self-administration of morphine in mice. Using the Scheduled High Alcohol Consumption (SHAC) procedure, SNAP 37889 (30 mg/kg) treated mice drank significantly less ethanol, sucrose and saccharin than vehicle treated mice. Using an operant paradigm, SNAP 37889 reduced morphine self-administration but failed to impact cue-induced relapse-like behaviour. SNAP 37889 had no significant effect on locomotor activity, motor co-ordination, anxiety, nor was SNAP 37889 itself positively reinforcing. Liver assays showed that there was no alteration in the rate of hepatic ethanol metabolism between SNAP 37889 and vehicle treated mice suggesting that the reduction in ethanol intake via SNAP 37889 is due to a central effect of GAL 3 signalling. This study implicates the GAL 3 receptor in consummatory drive which may have wider implications for the treatment of different addictions. Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.

  13. Nifedipine, a calcium channel blocker, inhibits advanced glycation end product (AGE)-elicited mesangial cell damage by suppressing AGE receptor (RAGE) expression via peroxisome proliferator-activated receptor-gamma activation

    Energy Technology Data Exchange (ETDEWEB)

    Matsui, Takanori [Department of Pathophysiology and Therapeutics of Diabetic Vascular Complications, Kurume University School of Medicine, 67 Asahi-machi, Kurume 830-0011 (Japan); Yamagishi, Sho-ichi, E-mail: shoichi@med.kurume-u.ac.jp [Department of Pathophysiology and Therapeutics of Diabetic Vascular Complications, Kurume University School of Medicine, 67 Asahi-machi, Kurume 830-0011 (Japan); Takeuchi, Masayoshi [Department of Pathophysiological Science, Faculty of Pharmaceutical Science, Hokuriku University, Kanazawa (Japan); Ueda, Seiji; Fukami, Kei; Okuda, Seiya [Department of Medicine, Kurume University School of Medicine, Kurume (Japan)

    2009-07-24

    The interaction between advanced glycation end products (AGE) and their receptor RAGE mediates the progressive alteration in renal architecture and loss of renal function in diabetic nephropathy. Oxidative stress generation and inflammation also play a central role in diabetic nephropathy. This study investigated whether and how nifedipine, a calcium channel blocker (CCB), blocked the AGE-elicited mesangial cell damage in vitro. Nifedipine, but not amlodipine, a control CCB, down-regulated RAGE mRNA levels and subsequently reduced reactive oxygen species (ROS) generation in AGE-exposed mesangial cells. AGE increased mRNA levels of vascular cell adhesion molecule-1 (VCAM-1) and induced monocyte chemoattractant protein-1 (MCP-1) production in mesangial cells, both of which were prevented by the treatment with nifedipine, but not amlodipine. The beneficial effects of nifedipine on AGE-exposed mesangial cells were blocked by the simultaneous treatment of GW9662, an inhibitor of peroxisome proliferator-activated receptor-{gamma} (PPAR-{gamma}). Although nifedipine did not affect expression levels of PPAR-{gamma}, it increased the PPAR-{gamma} transcriptional activity in mesangial cells. Our present study provides a unique beneficial aspect of nifedipine on diabetic nephropathy; it could work as an anti-inflammatory agent against AGE by suppressing RAGE expression in cultured mesangial cells via PPAR-{gamma} activation.

  14. Combination of Curcumin with an Anti-Transferrin Receptor Antibody Suppressed the Growth of Malignant Gliomas In vitro.

    Science.gov (United States)

    Wen, Xue; Cheng, Xiaoping; Hu, Dahai; Li, Wenmin; Ha, Jianli; Kang, Zhaochang; Zhang, Mingjun; Huang, Yinghao; Wu, Si

    2016-01-01

    Transferrin receptor (TfR) has been used as a target for the molecular cancer therapy due to its higher expression in a variety of tumors. Anti-TfR antibodies combined with chemotherapeutic drugs has showed great potential as a possible cancer therapeutic strategy. In our study, we investigated the anti-tumor effects of anti-TfR monoclonal antibody (mAb) alone or in combination with curcumin in vitro. We detected the apoptosis, proliferation and cell cycle of glioma cells after treated with anti-TfR mAb and curcumin alone or the combinations by flow cytometer. Anti-TfR mAb or curcumin could inhibit proliferation of tumor cells. Anti-TfR mAb marked S phase arrest and curcumin induced G2/M arrest in tumor cells. When anti-TfR mAb and curcumin were used simultaneously, a synergistic effect was detected in relation to tumor growth inhibition and the induction of cells necrosis. These results provided a potential role of anti-TfR mAb-containing curcumin in the treatment for gliomas.

  15. ICAM-1-Targeted Liposomes Loaded with Liver X Receptor Agonists Suppress PDGF-Induced Proliferation of Vascular Smooth Muscle Cells

    Science.gov (United States)

    Huang, Xu; Xu, Meng-Qi; Zhang, Wei; Ma, Sai; Guo, Weisheng; Wang, Yabin; Zhang, Yan; Gou, Tiantian; Chen, Yundai; Liang, Xing-Jie; Cao, Feng

    2017-05-01

    The proliferation of vascular smooth muscle cells (VSMCs) is one of the key events during the progress of atherosclerosis. The activated liver X receptor (LXR) signalling pathway is demonstrated to inhibit platelet-derived growth factor BB (PDGF-BB)-induced VSMC proliferation. Notably, following PDGF-BB stimulation, the expression of intercellular adhesion molecule-1 (ICAM-1) by VSMCs increases significantly. In this study, anti-ICAM-1 antibody-conjugated liposomes were fabricated for targeted delivery of a water-insoluble LXR agonist (T0901317) to inhibit VSMC proliferation. The liposomes were prepared by filming-rehydration method with uniform size distribution and considerable drug entrapment efficiency. The targeting effect of the anti-ICAM-T0901317 liposomes was evaluated by confocal laser scanning microscope (CLSM) and flow cytometry. Anti-ICAM-T0901317 liposomes showed significantly higher inhibition effect of VSMC proliferation than free T0901317 by CCk8 proliferation assays and BrdU staining. Western blot assay further confirmed that anti-ICAM-T0901317 liposomes inhibited retinoblastoma (Rb) phosphorylation and MCM6 expression. In conclusion, this study identified anti-ICAM-T0901317 liposomes as a promising nanotherapeutic approach to overcome VSMC proliferation during atherosclerosis progression.

  16. Suppression of cell proliferation and regulation of estrogen receptor alpha signaling pathway by arsenic trioxide on human breast cancer MCF-7 cells.

    Science.gov (United States)

    Chow, Stephanie K Y; Chan, Judy Y W; Fung, Kwok Pui

    2004-08-01

    In recent years, breast cancers have aroused much concern. Together with a growing incidence all over the world, the development of drug resistance to tamoxifen, the most commonly prescribed chemotherapeutic drug for breast cancer patients, has highlighted the importance of developing a new chemotherapeutic drug in combating breast cancer. With the aim of treating breast cancers, the anti-tumor effects of arsenic trioxide in MCF-7 cells have been studied. MCF-7 cells are estrogen responsive cells which mimic breast cancers at the early stage. 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay and direct cell counting were used to measure cell proliferation. The mechanisms of action were elucidated through the measurement of estrogen receptor (ER) binding, mRNA and protein levels of ERalpha and its activity. We have demonstrated that arsenic trioxide was capable of reducing cell survival in MCF-7 cells via the suppression of the estrogen-induced growth stimulatory effects in MCF-7 cells. Arsenic trioxide was shown to suppress the action of estrogen through the regulation of the ERalpha signaling pathway. Arsenic trioxide could down-regulate ERalpha mRNA and protein levels without competing with estrogen for ERalpha binding. Arsenic trioxide also inhibited the transcription activity mediated by the ERalpha signaling pathway and ultimately it down-regulated c-myc protein expression and inhibited cell entry to S phase under estrogen's stimulation. In conclusion, arsenic trioxide could inhibit the growth of MCF-7 cells by reducing the growth stimulatory effect of estrogen. As estrogen is a primary risk factor in promoting the growth of breast tumor cells, the anti-estrogenicity exhibited by arsenic trioxide sheds light on the therapy of breast cancer.

  17. Anticancer effect of genistein on BG-1 ovarian cancer growth induced by 17 β-estradiol or bisphenol A via the suppression of the crosstalk between estrogen receptor alpha and insulin-like growth factor-1 receptor signaling pathways

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Kyung-A; Park, Min-Ah; Kang, Nam-Hee; Yi, Bo-Rim; Hyun, Sang-Hwan; Jeung, Eui-Bae; Choi, Kyung-Chul, E-mail: kchoi@cbu.ac.kr

    2013-11-01

    The interaction between estrogen receptor (ER) and insulin-like growth factor-1 receptor (IGF-1R) signaling pathway plays an important role in proliferation of and resistance to endocrine therapy to estrogen dependent cancers. Estrogen (E2) upregulates the expression of components of IGF-1 system and induces the downstream of mitogenic signaling cascades via phosphorylation of insulin receptor substrate-1 (IRS-1). In the present study, we evaluated the xenoestrogenic effect of bisphenol A (BPA) and antiproliferative activity of genistein (GEN) in accordance with the influence on this crosstalk. BPA was determined to affect this crosstalk by upregulating mRNA expressions of ERα and IGF-1R and inducing phosphorylation of IRS-1 and Akt in protein level in BG-1 ovarian cancer cells as E2 did. In the mouse model xenografted with BG-1 cells, BPA significantly increased a tumor burden of mice and expressions of ERα, pIRS-1, and cyclin D1 in tumor mass compared to vehicle, indicating that BPA induces ovarian cancer growth by promoting the crosstalk between ER and IGF-1R signals. On the other hand, GEN effectively reversed estrogenicity of BPA by reversing mRNA and protein expressions of ERα, IGF-1R, pIRS-1, and pAkt induced by BPA in cellular model and also significantly decreased tumor growth and in vivo expressions of ERα, pIRS-1, and pAkt in xenografted mouse model. Also, GEN was confirmed to have an antiproliferative effect by inducing apoptotic signaling cascades. Taken together, these results suggest that GEN effectively reversed the increased proliferation of BG-1 ovarian cancer by suppressing the crosstalk between ERα and IGF-1R signaling pathways upregulated by BPA or E2.

  18. Peroxisome proliferator-activated receptor-gamma agonists suppress tissue factor overexpression in rat balloon injury model with paclitaxel infusion.

    Directory of Open Access Journals (Sweden)

    Jun-Bean Park

    Full Text Available The role and underlying mechanisms of rosiglitazone, a peroxisome proliferator-activated receptor-gamma (PPAR-γ agonist, on myocardial infarction are poorly understood. We investigated the effects of this PPAR-γ agonist on the expression of tissue factor (TF, a primary molecule for thrombosis, and elucidated its underlying mechanisms. The PPAR-γ agonist inhibited TF expression in response to TNF-α in human umbilical vein endothelial cells, human monocytic leukemia cell line, and human umbilical arterial smooth muscle cells. The overexpression of TF was mediated by increased phosphorylation of mitogen-activated protein kinase (MAPK, which was blocked by the PPAR-γ agonist. The effective MAPK differed depending on each cell type. Luciferase and ChIP assays showed that transcription factor, activator protein-1 (AP-1, was a pivotal target of the PPAR-γ agonist to lower TF transcription. Intriguingly, two main drugs for drug-eluting stent, paclitaxel or rapamycin, significantly exaggerated thrombin-induced TF expression, which was also effectively blocked by the PPAR-γ agonist in all cell types. This PPAR-γ agonist did not impair TF pathway inhibitor (TFPI in three cell types. In rat balloon injury model (Sprague-Dawley rats, n = 10/group with continuous paclitaxel infusion, the PPAR-γ agonist attenuated TF expression by 70±5% (n = 4; P<0.0001 in injured vasculature. Taken together, rosiglitazone reduced TF expression in three critical cell types involved in vascular thrombus formation via MAPK and AP-1 inhibitions. Also, this PPAR-γ agonist reversed the paclitaxel-induced aggravation of TF expression, which suggests a possibility that the benefits might outweigh its risks in a group of patients with paclitaxel-eluting stent implanted.

  19. Curcumin attenuates morphine antinociceptive tolerance through suppressing up-regulation of spinal Toll-like receptor 4 in rats

    Directory of Open Access Journals (Sweden)

    Fei GAO

    2017-12-01

    Full Text Available Objective To investigate the effects of curcumin (Cur on activation of spinal Toll-like receptor 4 (TLR4 and on the chronic antinociceptive tolerance of morphine. Methods Sixty male Sprague-Dawley rats with successful intrathecal catheterization were randomly divided into four groups (n=15: saline (NS group; morphine (MOR group; curcumin (Cur group and morphine plus curcumin (MOR+Cur group. A morphine tolerance model of rats was induced by intrathecal injection of morphine 15μg, once a day for 7 consecutive days in MOR and MOR+Cur group; 100μg curcumin was administered intrathecally once a day for 7 consecutive days in Cur and MOR+Cur group, 10μl saline was administered intrathecally once a day for 7 consecutive days in NS group. The effect of curcumin intrathecal catheterization on morphine antinociceptive tolerance was explored by the tail flick latency (TFL method and mechanical withdrawal threshold (MWT, and then the maximum possible potential effect (MPE was calculated. The immunofluorescence staining method was applied to detect the effect of curcumin on the activation of lumbar spinal microglia. Real-time PCR and Western blotting were used to evaluate the effect of curcumin on the expression of mRNA and protein of spinal TLR4. Results The %MPE TFL and %MPE MWT increased significantly in MOR+Cur group than in MOR group (P0.05. The lumbar spinal microglia increased markedly and the expressions of polyclonal antibody IBA-1 and TLR4 were significantly up-regulated in MOR group than in NS group (P0.05. Conclusion Curcumin may attenuate chronic morphine antinociceptive tolerance through inhibiting spinal TLR4 up-regulation. DOI: 10.11855/j.issn.0577-7402.2017.12.06

  20. MicroRNA-217 suppresses homocysteine-induced proliferation and migration of vascular smooth muscle cells via N-methyl-D-aspartic acid receptor inhibition.

    Science.gov (United States)

    Duan, Hongyan; Li, Yongqiang; Yan, Lijie; Yang, Haitao; Wu, Jintao; Qian, Peng; Li, Bing; Wang, Shanling

    2016-10-01

    Hyperhomocysteine has become a critical risk for atherosclerosis and can stimulate proliferation and migration of vascular smooth muscle cells (VSMCs). N-methyl-D-aspartic acid receptor (NMDAR) is a receptor of homocysteine and mediates the effects of homocysteine on VSMCs. Bioinformatics analysis has shown NMDAR is a potential target of microRNA-217 (miR-217), which exerts multiple functions in cancer tumorigenesis and carotid plaque progression. In this study, we sought to investigate the role of miR-217 in VSMCs phenotype transition under homocysteine exposure and elucidate its effect on atherosclerotic plaque formation. After treating with several doses of homocysteine (0-8 × 10(-4)  mol/L) for 24 hours, the expression of miR-217 in HA-VSMCs and rat aortic VSMCs was not altered. Intriguingly, the expression of NMDAR mRNA and protein was reduced by homocysteine in a dose-dependent manner. Transfection of miR-217 mimic significantly inhibited the proliferation and migration of VSMCs with homocysteine treatment, while transfection of miR-217 inhibitor promoted VSMCs migration. Moreover, miR-217 mimic down-regulated while miR-217 inhibitor up-regulated NMDAR protein expression but not NMDAR mRNA expression. Through luciferase reporter assay, we showed that miR-217 could directly bind to the 3'-UTR of NMDAR. MiR-217 mimic transfection also released the inhibition of cAMP-response element-binding protein (CREB)-PGC-1α signalling induced by homocysteine. Additionally, restoration of PGC-1α expression via AdPGC-1α infection markedly suppressed VSMCs proliferation through the degradation of NADPH oxidase (NOX1) and reduction of reactive oxygen species (ROS). Collectively, our study identified the role of miR-217 in regulating VSMCs proliferation and migration, which might serve as a target for atherosclerosis therapy. © 2016 John Wiley & Sons Australia, Ltd.

  1. A hepatoprotective Lindera obtusiloba extract suppresses growth and attenuates insulin like growth factor-1 receptor signaling and NF-kappaB activity in human liver cancer cell lines

    Directory of Open Access Journals (Sweden)

    Stroh Thorsten

    2011-05-01

    Full Text Available Abstract Background In traditional Chinese and Korean medicine, an aqueous extract derived from wood and bark of the Japanese spice bush Lindera obtusiloba (L.obtusiloba is applied to treat inflammations and chronic liver diseases including hepatocellular carcinoma. We previously demonstrated anti-fibrotic effects of L.obtusiloba extract in hepatic stellate cells. Thus, we here consequently examine anti-neoplastic effects of L.obtusiloba extract on human hepatocellular carcinoma (HCC cell lines and the signaling pathways involved. Methods Four human HCC cell lines representing diverse stages of differentiation were treated with L.obtusiloba extract, standardized according to its known suppressive effects on proliferation and TGF-β-expression. Beside measurement of proliferation, invasion and apoptosis, effects on signal transduction and NF-κB-activity were determined. Results L.obtusiloba extract inhibited proliferation and induced apoptosis in all HCC cell lines and provoked a reduced basal and IGF-1-induced activation of the IGF-1R signaling cascade and a reduced transcriptional NF-κB-activity, particularly in the poorly differentiated SK-Hep1 cells. Pointing to anti-angiogenic effects, L.obtusiloba extract attenuated the basal and IGF-1-induced expression of hypoxia inducible factor-1α, vascular endothelial growth factor, peroxisome proliferator-activated receptor-γ, cyclooxygenase-2 and inducible nitric oxide synthase. Conclusions The traditional application of the extract is confirmed by our experimental data. Due to its potential to inhibit critical receptor tyrosine kinases involved in HCC progression via the IGF-1 signaling pathway and NF-κB, the standardized L.obtusiloba extract should be further analysed for its active compounds and explored as (complementary treatment option for HCC.

  2. Blockade of A2b Adenosine Receptor Reduces Tumor Growth and Immune Suppression Mediated by Myeloid-Derived Suppressor Cells in a Mouse Model of Melanoma

    Directory of Open Access Journals (Sweden)

    Raffaella Iannone

    2013-12-01

    Full Text Available The A2b receptor (A2bR belongs to the adenosine receptor family. Emerging evidence suggest that A2bR is implicated in tumor progression in some murine tumor models, but the therapeutic potential of targeting A2bR in melanoma has not been examined. This study first shows that melanoma-bearing mice treated with Bay 60-6583, a selective A2bR agonist, had increased melanoma growth. This effect was associated with higher levels of immune regulatory mediators interleukin-10 (IL-10 and monocyte chemoattractant protein 1 (MCP-1 and accumulation of tumor-associated CD11b positive Gr1 positive cells (CD11b+Gr1+ myeloid-derived suppressor cells (MDSCs. Depletion of CD11b+Gr1+ cells completely reversed the protumor activity of Bay 60-6583. Conversely, pharmacological blockade of A2bR with PSB1115 reversed immune suppression in the tumor microenvironment, leading to a significant melanoma growth delay. PSB1115 treatment reduced both levels of IL-10 and MCP-1 and CD11b+Gr1+ cell number in melanoma lesions. These effects were associated with higher frequency of tumor-infiltrating CD8 positive (CD8+ T cells and natural killer T (NKT cells and increased levels of T helper 1 (Th1-like cytokines. Adoptive transfer of CD11b+Gr1+ cells abrogated the antitumor activity of PSB1115. These data suggest that the antitumor activity of PSB1115 relies on its ability to lower accumulation of tumor-infiltrating MDSCs and restore an efficient antitumor T cell response. The antitumor effect of PSB1115 was not observed in melanoma-bearing nude mice. Furthermore, PSB1115 enhanced the antitumor efficacy of dacarbazine. These data indicate that A2bR antagonists such as PSB1115 should be investigated as adjuvants in the treatment of melanoma.

  3. M3 subtype of muscarinic acetylcholine receptor promotes cardioprotection via the suppression of miR-376b-5p.

    Directory of Open Access Journals (Sweden)

    Zhenyu Pan

    Full Text Available The M(3 subtype of muscarinic acetylcholine receptors (M(3-mAChR plays a protective role in myocardial ischemia and microRNAs (miRNAs participate in many cardiac pathophysiological processes, including ischemia-induced cardiac injury. However, the role of miRNAs in M(3-mAChR mediated cardioprotection remains unexplored. The present study was designed to identify miRNAs that are involved in cardioprotective effects of M(3-mAChR against myocardial ischemia and elucidate the underlying mechanisms. We established rat model of myocardial ischemia and performed miRNA microarray analysis to identify miRNAs involved in the cardioprotection of M(3-mAChR. In H9c2 cells, the viability, intracellular free Ca(2+ concentration ([Ca(2+]i, intracellular reactive oxygen species (ROS, miR-376b-5p expression level, brain derived neurophic factor (BDNF and nuclear factor kappa-B (NF-κB levels were measured. Our results demonstrated that M(3-mAChR protected myocardial ischemia injury. Microarray analysis and qRT-PCR revealed that miR-376b-5p was significantly up-regulated in ischemic heart tissue and the M(3-mAChRs agonist choline reversed its up-regulation. In vitro, miR-376b-5p promoted H(2O(2-induced H9c2 cell injuries measured by cells viability, [Ca(2+]i and ROS. Western blot and luciferase assay identified BDNF as a direct target of miR-376b-5p. M(3-mAChR activated NF-κB and thereby inhibited miR-376b-5p expression. Our data show that a novel M(3-mAChR/NF-κB/miR-376b-5p/BDNF axis plays an important role in modulating cardioprotection. MiR-376b-5p promotes myocardial ischemia injury possibly by inhibiting BDNF expression and M(3-mAChR provides cardioprotection at least partially mediated by the downregulation of miR-376b-5p through NF-κB. These findings provide new insight into the potential mechanism by which M(3-mAChR provides cardioprotection against myocardial ischemia injury.

  4. Overexpression of M3 Muscarinic Receptor Suppressed Adverse Electrical Remodeling in Hypertrophic Myocardium Via Increasing Repolarizing K+ Currents

    Directory of Open Access Journals (Sweden)

    Xue Chen

    2017-09-01

    Full Text Available Background/Aims: Cardiac hypertrophy (CH is an adaptive response to diverse cardiovascular conditions, which is accompanied by adverse electrical remodeling manifested as abnormal K+ channel activities. M3 subtype of muscarinic acetylcholine receptor (M3-mAChR is a novel regulator of cardiac electrical activity. In this study we aim to explore if the overexpression of M3-mAChR could attenuate the adverse electrical remodeling in CH and then uncover its underlying electrophysiological mechanisms. Methods: Transgenic mice with M3-mAChR overexpression (M3-TG and wild type (WT mice were subjected to transverse aortic constriction (TAC to induce CH. Myocardial hypertrophy and cardiac function were quantified by the measurement of echocardiography, electrocardiogram, heart weight and tibia length. Whole-cell and signal-cell patch-clamp were employed to record electrophysiological properties by acute isolation of acutely isolated ventricular cardiomyocytes and Western blot was carried out to evaluate the Kir2.1and Kv4.2/4.3 protein levels in left ventricular tissue. Results: Compared with WT group, the elevation of cardiac index, including heart weight/body weight index and heart weight/tibia length index confirmed the myocardial hypertrophic growth induced by TAC. Echocardiography detection revealed that the TAC-treated mice showed an obvious increase in the thickness of left ventricular posterior wall (LVPW and ejection fraction (EF due to compensatory hypertrophy, which attenuated by the overexpression of M3-mAChR. Pressure overload induced a prolongation of QTc interval in WT mice, an effect blunted in M3-TG mice. Furthermore, compared with WT mice, M3-mAChR overexpression in hypertrophic myocardium accelerated cardiac repolarization and shortened action potential duration, and thus correcting the prolongation of QTc interval. Moreover, M3-TG mice have the greater current density of IK1 and Ito in ventricular myocytes after TAC compared with WT

  5. Decoy receptor 3 suppresses FasL-induced apoptosis via ERK1/2 activation in pancreatic cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yi; Li, Dechun; Zhao, Xin; Song, Shiduo; Zhang, Lifeng; Zhu, Dongming [Department of General Surgery, The First Affiliated Hospital of Soochow University, Suzhou 215006 (China); Wang, Zhenxin [Department of Oncology, The First Affiliated Hospital of Soochow University, Suzhou 215006 (China); Chen, Xiaochen [Department of Pathology, The Obstetrics & Gynecology Hospital of Fudan University, Shanghai 200090 (China); Zhou, Jian, E-mail: zhoujian20150602@126.com [Department of General Surgery, The First Affiliated Hospital of Soochow University, Suzhou 215006 (China)

    2015-08-07

    Resistance to Fas Ligand (FasL) mediated apoptosis plays an important role in tumorigenesis. Decoy receptor 3 (DcR3) is reported to interact with FasL and is overexpressed in some malignant tumors. We sought to investigate the role of DcR3 in resistance to FasL in pancreatic cancer. We compared expression of apoptosis related genes between FasL-resistant SW1990 and FasL-sensitive Patu8988 pancreatic cell lines by microarray analysis. We explored the impact of siRNA knockdown of, or exogenous supplementation with, DcR3 on FasL-induced cell growth inhibition in pancreatic cancer cell lines and expression of proteins involved in apoptotic signaling. We assessed the level of DcR3 protein and ERK1/2 phosphorylation in tumor and non-tumor tissue samples of 66 patients with pancreatic carcinoma. RNAi knockdown of DcR3 expression in SW1990 cells reduced resistance to FasL-induced apoptosis, and supplementation of Patu8988 with rDcR3 had the opposite effect. RNAi knockdown of DcR3 in SW1990 cells elevated expression of caspase 3, 8 and 9, and reduced ERK1/2 phosphorylation (P < 0.05), but did not alter phosphorylated-Akt expression. 47 tumor tissue specimens, but only 15 matched non-tumor specimens stained for DcR3 (χ{sup 2} = 31.1447, P < 0.001). The proliferation index of DcR3 positive specimens (14.26  ±  2.67%) was significantly higher than that of DcR3 negative specimens (43.58  ±  7.88%, P < 0.01). DcR3 expression positively correlated with p-ERK1/2 expression in pancreatic cancer tissues (r = 0.607, P < 0.001). DcR3 enhances ERK1/2 phosphorylation and opposes FasL signaling in pancreatic cancer cells. - Highlights: • We investigated the role of DcR3 in FasL resistance in pancreatic cancer. • Knockdown of DcR3 in SW1990 cells reduced resistance to FasL-induced apoptosis. • DcR3 knockdown also elevated caspase expression, and reduced ERK1/2 phosphorylation. • Tumor and non-tumor tissues were collected from 66 pancreatic carcinoma patients

  6. Tesofensine, a novel triple monoamine reuptake inhibitor, induces appetite suppression by indirect stimulation of alpha1 adrenoceptor and dopamine D1 receptor pathways in the diet-induced obese rat

    DEFF Research Database (Denmark)

    Axel, Anne Marie Dixen; Mikkelsen, Jens D; Hansen, Henrik H

    2010-01-01

    Tesofensine is a novel monoamine reuptake inhibitor that inhibits both norepinephrine, 5-HT, and dopamine (DA) reuptake function. Tesofensine is currently in clinical development for the treatment of obesity, however, the pharmacological basis for its strong effect in obesity management...... is not clarified. Using a rat model of diet-induced obesity (DIO), we characterized the pharmacological mechanisms underlying the appetite suppressive effect of tesofensine. DIO rats treated with tesofensine (2.0 mg/kg, s.c.) for 16 days showed significantly lower body weights than vehicle-treated DIO rats, being...... antagonist), or ritanserin (0.03 mg/kg, 5-HT(2A/C) receptor antagonist). Hence, the mechanism underlying the suppression of feeding by tesofensine in the obese rat is dependent on the drug's ability to indirectly stimulate alpha(1) adrenoceptor and DA D(1) receptor function....

  7. Enhanced suppression of adenovirus replication by triple combination of anti-adenoviral siRNAs, soluble adenovirus receptor trap sCAR-Fc and cidofovir.

    Science.gov (United States)

    Pozzuto, Tanja; Röger, Carsten; Kurreck, Jens; Fechner, Henry

    2015-08-01

    Adenoviruses (Ad) generally induce mild self-limiting respiratory or intestinal infections but can also cause serious disease with fatal outcomes in immunosuppressed patients. Antiviral drug therapy is an important treatment for adenoviral infections but its efficiency is limited. Recently, we have shown that gene silencing by RNA interference (RNAi) is a promising new approach to inhibit adenoviral infection. In the present in vitro study, we examined whether the efficiency of an RNAi-based anti-adenoviral therapy can be further increased by combination with a virus receptor trap sCAR-Fc and with the antiviral drug cidofovir. Initially, three siRNAs, siE1A_4, siIVa2_2 and Pol-si2, targeting the adenoviral E1A, IVa2 and DNA polymerase mRNAs, respectively, were used for gene silencing. Replication of the Ad was inhibited in a dose dependent manner by each siRNA, but the efficiency of inhibition differed (Pol-si2>siIVa2_2>siE1A_4). Double or triple combinations of the siRNAs compared with single siRNAs did not result in a measurably higher suppression of Ad replication. Combination of the siRNAs (alone or mixes of two or three siRNAs) with sCAR-Fc markedly increased the suppression of adenoviral replication compared to the same siRNA treatment without sCAR-Fc. Moreover, the triple combination of a mix of all three siRNAs, sCAR-Fc and cidofovir was about 23-fold more efficient than the combination of siRNAs mix/sCAR-Fc and about 95-fold more efficient than the siRNA mix alone. These data demonstrate that co-treatment of cells with sCAR-Fc and cidofovir is suitable to increase the efficiency of anti-adenoviral siRNAs. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. Ethanol Inhibits High-Affinity Immunoglobulin E Receptor (FcεRI) Signaling in Mast Cells by Suppressing the Function of FcεRI-Cholesterol Signalosome

    Science.gov (United States)

    Draberova, Lubica; Paulenda, Tomas; Halova, Ivana; Potuckova, Lucie; Bugajev, Viktor; Bambouskova, Monika; Tumova, Magda; Draber, Petr

    2015-01-01

    Ethanol has multiple effects on biochemical events in a variety of cell types, including the high-affinity immunoglobulin E receptor (FcεRI) signaling in antigen-activated mast cells. However, the underlying molecular mechanism remains unknown. To get better understanding of the effect of ethanol on FcεRI-mediated signaling we examined the effect of short-term treatment with non-toxic concentrations of ethanol on FcεRI signaling events in mouse bone marrow-derived mast cells. We found that 15 min exposure to ethanol inhibited antigen-induced degranulation, calcium mobilization, expression of proinflammatory cytokine genes (tumor necrosis factor-α, interleukin-6, and interleukin-13), and formation of reactive oxygen species in a dose-dependent manner. Removal of cellular cholesterol with methyl-β-cyclodextrin had a similar effect and potentiated some of the inhibitory effects of ethanol. In contrast, exposure of the cells to cholesterol-saturated methyl-β-cyclodextrin abolished in part the inhibitory effect of ethanol on calcium response and production of reactive oxygen species, supporting lipid-centric theories of ethanol action on the earliest stages of mast cell signaling. Further studies showed that exposure to ethanol and/or removal of cholesterol inhibited early FcεRI activation events, including tyrosine phosphorylation of the FcεRI β and γ subunits, SYK kinases, LAT adaptor protein, phospholipase Cγ, STAT5, and AKT and internalization of aggregated FcεRI. Interestingly, ethanol alone, and particularly in combination with methyl-β-cyclodextrin, enhanced phosphorylation of negative regulatory tyrosine 507 of LYN kinase. Finally, we found that ethanol reduced passive cutaneous anaphylactic reaction in mice, suggesting that ethanol also inhibits FcεRI signaling under in vivo conditions. The combined data indicate that ethanol interferes with early antigen-induced signaling events in mast cells by suppressing the function of Fc

  9. Ligand activation of peroxisome proliferator-activated receptor delta suppresses cathepsin B expression in human endothelial cells in a posttranslational manner.

    Science.gov (United States)

    Reichenbach, Gabi; Starzinski-Powitz, Anna; Doll, Monika; Hrgovic, Igor; Valesky, Eva Maria; Kippenberger, Stefan; Bernd, August; Kaufmann, Roland; Meissner, Markus

    2012-10-01

    Peroxisome proliferator-activated receptor (PPAR) delta agonists are known to have distinct anti-inflammatory and antitumor effects; though, the knowledge regarding their mode of action has thus far been limited. Different cathepsins have been shown to be upregulated in a broad range of pathological events, such as rheumatoid arthritis, psoriasis, atherosclerosis and diverse tumor entities, for example melanoma. Recent work demonstrated that cathepsin B in particular is an important pro-angiogenic protease in various pathological conditions. We therefore analysed whether cathepsins are a valid target for PPARδ agonists. This study reveals an inhibitory effect of two commonly used PPARδ agonists, GW501516 and L-165,041, on the protein expression and enzyme activity of cathepsin B in human endothelial cells. In contrast, no inhibitory effects were observed on cathepsin L and cathepsin D protein expression after treatment with PPARδ agonists. Furthermore, the results substantiate that PPARδ activators mediate their inhibitory action in a PPARδ-dependent manner and that the underlying regulatory mechanism is not based on a transcriptional but rather on a posttranslational mode of action, via the reduction in the cathepsin B protein half-life. Mechanisms conveying the suppressive effect by 5'-alternative splicing, a 3'-UTR-dependent way or by miRNA could be excluded. The data of this study explore cathepsin B as a new valid target for PPARδ agonists in endothelial cells. The results bolster other studies demonstrating PPARδ agonists as anti-inflammatory and anticarcinogenic agents and thus might have the potential to help to develop new pharmaceutical drugs. © 2012 John Wiley & Sons A/S.

  10. Impact of suppressing retinoic acid-related orphan receptor gamma t (ROR)γt in ameliorating central nervous system autoimmunity.

    Science.gov (United States)

    Yang, Y; Winger, R C; Lee, P W; Nuro-Gyina, P K; Minc, A; Larson, M; Liu, Y; Pei, W; Rieser, E; Racke, M K; Lovett-Racke, A E

    2015-01-01

    Multiple sclerosis (MS) is an immune-mediated chronic central nervous system (CNS) disease affecting more than 400 000 people in the United States. Myelin-reactive CD4 T cells play critical roles in the formation of acute inflammatory lesions and disease progression in MS and experimental autoimmune encephalomyelitis (EAE), a well-defined mouse model for MS. Current MS therapies are only partially effective, making it necessary to develop more effective therapies that specifically target pathogenic myelin-specific CD4 T cells for MS treatment. While suppressing T-bet, the key transcription factor in T helper type 1 (Th1) cells, has been demonstrated to be beneficial in prevention and treatment of EAE, the therapeutic potential of retinoic acid-related orphan receptor gamma t (ROR)γt, the key transcription factor for Th17 cells, has not been well-characterized. In this study, we characterized the correlation between RORγt expression and other factors affecting T cell encephalitogenicity and evaluated the therapeutic potential of targeting RORγt by siRNA inhibition of RORγt. Our data showed that RORγt expression correlates with interleukin (IL)-17 production, but not with the encephalitogenicity of myelin-specific CD4 T cells. IL-23, a cytokine that enhances encephalitogenicity, does not enhance RORγt expression significantly. Additionally, granulocyte-macrophage colony-stimulating factor (GM-CSF) levels, which correlate with the encephalitogenicity of different myelin-specific CD4 T cell populations, do not correlate with RORγt. More importantly, inhibiting RORγt expression in myelin-specific CD4 T cells with an siRNA does not reduce disease severity significantly in adoptively transferred EAE. Thus, RORγt is unlikely to be a more effective therapeutic target for ameliorating pathogenicity of encephalitogenic CD4 T cells. © 2014 British Society for Immunology.

  11. Clinical characteristics predict benefits from eptifibatide therapy during coronary stenting: insights from the Enhanced Suppression of the Platelet IIb/IIIa Receptor With Integrilin Therapy (ESPRIT) trial.

    Science.gov (United States)

    Puma, Joseph A; Banko, Lesan T; Pieper, Karen S; Sacchi, Terrence J; O'Shea, J Conor; Dery, Jean Pierre; Tcheng, James E

    2006-02-21

    In order to determine a differential benefit from treatment, we compared the long-term outcome of high-risk versus low-risk patients and evaluated survival free from death or myocardial infarction at one year. Newer anticoagulant strategies during percutaneous coronary intervention have necessitated a reanalysis of the role of intravenous GP IIb/IIIa inhibitors. The Enhanced Suppression of the Platelet IIb/IIIa Receptor with Integrilin Therapy trial randomized 2,064 patients undergoing nonurgent coronary stent implantation to eptifibatide or placebo. High-risk characteristics were defined as age >75 years, diabetes, elevated cardiac markers, ST-segment elevation myocardial infarction within 7 days, or unstable angina within 48 h of randomization. Age <5 years, absence of diabetes, and any other reason for admission were considered low risk characterstics. There were 1,018 patients in the high-risk group (50.8% eptifibatide, 49.2% placebo) and 1,045 patients in the low-risk group (50.0% eptifibatide, 50.0% placebo). Baseline demographics were similar in both groups except for more hypertension (63% vs. 55%, respectively), peripheral vascular disease (8.2% vs. 5.2%, respectively), prior stroke (5.5% vs. 3.2%, respectively), and female gender (33% vs. 22%, respectively) in the high-risk than the low-risk group. At one year, the composite end point of death or myocardial infarction occurred in 15.89% of placebo patients and 7.99% of eptifibatide patients in the high-risk group and 9.02% of the placebo and 8.11% of eptifibatide patients in the low-risk group. Although eptifibatide treatment improved outcomes for all patients, preprocedural clinical characteristics can define a subgroup of patients who may derive greatest benefit from its use during coronary stent placement.

  12. Benzo[a]pyrene diol epoxide suppresses retinoic acid receptor-β2 expression by recruiting DNA (cytosine-5--methyltransferase 3A

    Directory of Open Access Journals (Sweden)

    Xu Xiao-Chun

    2010-04-01

    Full Text Available Abstract Tobacco smoke is an important risk factor for various human cancers, including esophageal cancer. How benzo [a]pyrene diol epoxide (BPDE, a carcinogen present in tobacco smoke as well as in environmental pollution, induces esophageal carcinogenesis has yet to be defined. In this study, we investigated the molecular mechanism responsible for BPDE-suppressed expression of retinoic acid receptor-beta2 (RAR-β2 in esophageal cancer cells. We treated esophageal cancer cells with BPDE before performing methylation-specific polymerase chain reaction (MSP to find that BPDE induced methylation of the RAR-β2 gene promoter. We then performed chromatin immunoprecipitation (ChIP assays to find that BPDE recruited genes of the methylation machinery into the RAR-β2 gene promoter. We found that BPDE recruited DNA (cytosine-5--methyltransferase 3 alpha (DNMT3A, but not beta (DNMT3B, in a time-dependent manner to methylate the RAR-β2 gene promoter, which we confirmed by reverse transcription-polymerase chain reaction (RT-PCR analysis of the reduced RAR-β2 expression in these BPDE-treated esophageal cancer cell lines. However, BPDE did not significantly change DNMT3A expression, but it slightly reduced DNMT3B expression. DNA methylase inhibitor 5-aza-2'-deoxycytidine (5-Aza and DNMT3A small hairpin RNA (shRNA vector antagonized the effects of BPDE on RAR-β2 expressions. Transient transfection of the DNMT3A shRNA vector also antagonized BPDE's effects on expression of RAR-β2, c-Jun, phosphorylated extracellular signal-regulated protein kinases 1/2 (ERK1/2, and cyclooxygenase-2 (COX-2, suggesting a possible therapeutic effect. The results of this study form the link between the esophageal cancer risk factor BPDE and the reduced RAR-β2 expression.

  13. Ethanol Inhibits High-Affinity Immunoglobulin E Receptor (FcεRI) Signaling in Mast Cells by Suppressing the Function of FcεRI-Cholesterol Signalosome.

    Science.gov (United States)

    Draberova, Lubica; Paulenda, Tomas; Halova, Ivana; Potuckova, Lucie; Bugajev, Viktor; Bambouskova, Monika; Tumova, Magda; Draber, Petr

    2015-01-01

    Ethanol has multiple effects on biochemical events in a variety of cell types, including the high-affinity immunoglobulin E receptor (FcεRI) signaling in antigen-activated mast cells. However, the underlying molecular mechanism remains unknown. To get better understanding of the effect of ethanol on FcεRI-mediated signaling we examined the effect of short-term treatment with non-toxic concentrations of ethanol on FcεRI signaling events in mouse bone marrow-derived mast cells. We found that 15 min exposure to ethanol inhibited antigen-induced degranulation, calcium mobilization, expression of proinflammatory cytokine genes (tumor necrosis factor-α, interleukin-6, and interleukin-13), and formation of reactive oxygen species in a dose-dependent manner. Removal of cellular cholesterol with methyl-β-cyclodextrin had a similar effect and potentiated some of the inhibitory effects of ethanol. In contrast, exposure of the cells to cholesterol-saturated methyl-β-cyclodextrin abolished in part the inhibitory effect of ethanol on calcium response and production of reactive oxygen species, supporting lipid-centric theories of ethanol action on the earliest stages of mast cell signaling. Further studies showed that exposure to ethanol and/or removal of cholesterol inhibited early FcεRI activation events, including tyrosine phosphorylation of the FcεRI β and γ subunits, SYK kinases, LAT adaptor protein, phospholipase Cγ, STAT5, and AKT and internalization of aggregated FcεRI. Interestingly, ethanol alone, and particularly in combination with methyl-β-cyclodextrin, enhanced phosphorylation of negative regulatory tyrosine 507 of LYN kinase. Finally, we found that ethanol reduced passive cutaneous anaphylactic reaction in mice, suggesting that ethanol also inhibits FcεRI signaling under in vivo conditions. The combined data indicate that ethanol interferes with early antigen-induced signaling events in mast cells by suppressing the function of Fc

  14. Angiotensin II receptor blockers suppress the release of stromal cell-derived factor-1α from infarcted myocardium in patients with acute myocardial infarction.

    Science.gov (United States)

    Yoshizaki, Toru; Uematsu, Manabu; Obata, Jun-Ei; Nakamura, Takamitsu; Fujioka, Daisuke; Watanabe, Kazuhiro; Nakamura, Kazuto; Kugiyama, Kiyotaka

    2018-04-01

    Although angiotensin II receptor blockers (ARBs) have been shown to have anti-inflammatory effects on infarcted myocardium in experimental models, little is known in humans. Stromal cell-derived factor-1α (SDF-1α), a pro-inflammatory chemokine, is released from infarcted tissue in patients with acute myocardial infarction (AMI). This study examined whether ARBs suppress SDF-1α production in the infarcted lesion in patients with AMI. SDF-1α levels were measured by enzyme-linked immunosorbent assays in plasma obtained from the aortic root (AO) and the anterior interventricular vein (AIV) in 50 patients with an anterior AMI. Measurement of SDF-1α levels and left ventriculography were repeated at discharge and 6 months after AMI. Patients were divided into 2 groups according to treatment with ARBs, which were administered at the discretion of the attending physician after admission. The AIV-AO gradient of SDF-1α, reflecting SDF-1α release from the infarcted myocardial region, decreased between the time of discharge and 6 months after AMI in patients taking an ARB. In contrast, the SDF-1α transcardiac gradient did not change in patients not taking an ARB. Among the clinical parameters tested, only the use of ARBs was significantly associated with percent changes in the SDF-1α transcardiac gradient from the time of discharge to 6 months after AMI in a linear regression analysis (r=-0.31, p=0.03). The SDF-1α transcardiac gradient 6 months after AMI was inversely correlated with the percent change in left ventricular (LV) ejection fraction (r=-0.52, pinfarcted myocardial region, which was associated with improvement in LV dysfunction and adverse remodeling in AMI survivors. Copyright © 2017 Japanese College of Cardiology. Published by Elsevier Ltd. All rights reserved.

  15. Effects of meteorology on diurnal and nocturnal levels of priority polycyclic aromatic hydrocarbons and elemental and organic carbon in PM 10 at a source and a receptor area in Mexico City

    Science.gov (United States)

    Guzmán-Torres, Diana; Eiguren-Fernández, Arantza; Cicero-Fernández, Pablo; Maubert-Franco, Marisela; Retama-Hernández, Armando; Ramos Villegas, Rafael; Miguel, Antonio H.

    PM 10 levels of the 16 US-EPA Priority Pollutant polycyclic aromatic hydrocarbons (PAHs) were measured from March 17 to 31, 2003, in 8-h time bins (morning, afternoon and nighttime) at Merced, a source site dominated by vehicular traffic emissions near the center of Mexico City, and at Pedregal, a receptor area located downwind in a residential area of low traffic. Along with PAH, elemental (EC) and organic carbon (OC), mass, and prevailing meteorological parameters were measured. At the source location, measured concentrations of benzo[ a]pyrene (BAP), an agent suspected of being carcinogenic to humans and of causing oxidative DNA damage, reached concentrations as high as 2.04 and 2.11 ng m -3 during the morning of a weekday and the night period of a holiday. Compared with source dominated areas in Central Los Angeles, the BAP levels found in Central Mexico City are approximately 6 times higher. Benzo[ ghi]perylene (BGP) levels were, in general, the highest among the target PAH, both at the source (7.2 ng m -3) and the receptor site (2.8 ng m -3), suggesting that, at both locations, exhaust emission by light-duty (LD) vehicles is an important contributor to the atmospheric PAH burden. Higher PAH concentrations were observed during the morning period (5:00-13:00 h) at the source and the receptor site. The concentrations of PAHs found predominantly in the particle-phase (MW > 202) correlated well ( r = 0.57-0.71) with the occurrence of surface thermal inversions and with mixing heights ( r = -0.57 to -0.72). Organic and elemental carbon ratios also indicated that Pedregal is impacted by secondary aerosols during the afternoon hours.

  16. receptores

    Directory of Open Access Journals (Sweden)

    Salete Regina Daronco Benetti

    2006-01-01

    Full Text Available Se trata de un estudio etnográfico, que tuvo lo objetivo de interpretar el sistema de conocimiento y del significado atribuidos a la sangre referente a la transfusión sanguínea por los donadores y receptores de un banco de sangre. Para la colecta de las informaciones se observaron los participantes y la entrevista etnográfica se realizó el análisis de dominio, taxonómicos y temáticos. Los dominios culturales fueron: la sangre es vida: fuente de vida y alimento valioso; creencias religiosas: fuentes simbólicas de apoyos; donación sanguínea: un gesto colaborador que exige cuidarse, gratifica y trae felicidad; donación sanguínea: fuente simbólica de inseguridad; estar enfermo es una condición para realizar transfusión sanguínea; transfusión sanguínea: esperanza de vida; Creencias populares: transfusión sanguínea como riesgo para la salud; donadores de sangre: personas benditas; donar y recibir sangre: como significado de felicidad. Temática: “líquido precioso que origina, sostiene, modifica la vida, provoca miedo e inseguridad”.

  17. Dioxin-induced retardation of development through a reduction in the expression of pituitary hormones and possible involvement of an aryl hydrocarbon receptor in this defect: A comparative study using two strains of mice with different sensitivities to dioxin

    Energy Technology Data Exchange (ETDEWEB)

    Takeda, Tomoki; Taura, Junki; Hattori, Yukiko; Ishii, Yuji; Yamada, Hideyuki, E-mail: hyamada@phar.kyushu-u.ac.jp

    2014-08-01

    We have previously revealed that treating pregnant rats with 2,3,7,8-tetracholorodibenzo-p-dioxin (TCDD) reduces the expression of gonadotropins and growth hormone (GH) in the fetal and neonatal pituitary. A change in gonadotropin expression impairs the testicular expression of steroidogenic proteins in perinatal pups, and imprint defects in sexual behavior after reaching maturity. In this study, we examined whether TCDD also affects the expression of gonadotropin and GH in mice using C57BL/6J and DBA/2J strains which express the aryl hydrocarbon receptor (Ahr) exhibiting a different affinity for TCDD. When pregnant C57BL/6J mice at gestational day (GD) 12 were given oral TCDD (0.2–20 μg/kg), all doses significantly attenuated the pituitary expression of gonadotropin mRNAs in fetuses at GD18. On the other hand, in DBA/2J mice, a much higher dose of TCDD (20 μg/kg) was needed to produce a significant attenuation. Such reduction in the C57BL/6J strain continued until at least postnatal day (PND) 4. In agreement with this, TCDD reduced the testicular expression of steroidogenic proteins in C57BL/6J neonates at PND2 and 4, although the same did not occur in the fetal testis and ovary. Furthermore, TCDD reduced the perinatal expression of GH, litter size and the body weight of newborn pups only in the C57BL/6J strain. These results suggest that 1) also in mice, maternal exposure to TCDD attenuates gonadotropin-regulated steroidogenesis and GH expression leading to the impairment of pup development and sexual immaturity; and 2) Ahr activation during the late fetal and early postnatal stages is required for these defects. - Highlights: • The effect of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on mouse growth was studied. • TCDD reduced the levels of luteinizing hormone and growth hormone in perinatal pups. • Maternal exposure to TCDD also attenuated testicular steroidogenesis in pups. • The above effects of TCDD were more pronounced in C57BL/6J than in DBA/2J

  18. Aryl hydrocarbon receptor-dependent upregulation of Cyp1b1 by TCDD and diesel exhaust particles in rat brain microvessels

    Directory of Open Access Journals (Sweden)

    Jacob Aude

    2011-08-01

    Full Text Available Abstract Background AhR activates the transcription of several target genes including CYP1B1. Recently, we showed CYP1B1 as the major cytochrome P450 (CYP enzyme expressed in human brain microvessels. Here, we studied the effect of AhR activation by environmental pollutants on the expression of Cyp1b1 in rat brain microvessels. Methods Expression of AhR and Cyp1b1 was detected in isolated rat brain microvessels. AhR was immunovisualised in brain microvessel endothelial cells. The effect of AhR ligands on Cyp1b1 expression was studied using isolated brain microvessels after ex vivo and/or in vivo exposure to TCDD, heavy hydrocarbons containing diesel exhaust particles (DEP or Δ9-tetrahydrocannabinol (Δ9-THC. Results After ex vivo exposure to TCDD (a highly potent AhR ligand for 3 h, Cyp1b1 expression was significantly increased by 2.3-fold in brain microvessels. A single i.p. dose of TCDD also increased Cyp1b1 transcripts (22-fold and Cyp1b1 protein (2-fold in rat brain microvessels at 72 h after TCDD. Likewise, DEP treatment (in vivo and ex vivo strongly induced Cyp1b1 protein in brain microvessels. DEP-mediated Cyp1b1 induction was inhibited by actinomycin D, cycloheximide, or by an AhR antagonist. In contrast, a sub-chronic in vivo treatment with Δ9-THC once daily for 7 seven days had no effect on Cyp1b1 expression Conclusions Our results show that TCDD and DEP strongly induced Cyp1b1 in rat brain microvessels, likely through AhR activation.

  19. Proteomic pathway analysis of the hippocampus in schizophrenia and bipolar affective disorder implicates 14-3-3 signaling, aryl hydrocarbon receptor signaling, and glucose metabolism: potential roles in GABAergic interneuron pathology.

    Science.gov (United States)

    Schubert, Klaus Oliver; Föcking, Melanie; Cotter, David R

    2015-09-01

    Neuropathological changes of the hippocampus have been associated with psychotic disorders such as schizophrenia and bipolar disorder. Recent work has particularly implicated hippocampal GABAergic interneurons in the pathophysiology of these diseases. However, the molecular mechanisms underlying structural and cellular hippocampal pathology remain poorly understood. We used data from comprehensive difference-in-gel electrophoresis (2-D DIGE) investigations of postmortem human hippocampus of people with schizophrenia and bipolar disorder, covering the acidic (isoelectric point (pI) between pH4 and 7) and, separately, the basic (pI between pH6 and 11) sub-proteome, for Ingenuity Pathway Analysis (IPA) of implicated protein networks and pathways. Comparing disease and control cases, we identified 58 unique differentially expressed proteins in schizophrenia, and 70 differentially expressed proteins in bipolar disorder, using mass spectrometry. IPA implicated, most prominently, 14-3-3 and aryl hydrocarbon receptor signaling in schizophrenia, and gluconeogenesis/glycolysis in bipolar disorder. Both disorders were characterized by alterations of proteins involved in the oxidative stress response, mitochondrial function, and protein-endocytosis, -trafficking, -degradation, and -ubiquitination. These findings are interpreted with a focus on GABAergic interneuron pathology in the hippocampus. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. Aryl hydrocarbon receptor (AHR): "pioneer member" of the basic-helix/loop/helix per-Arnt-sim (bHLH/PAS) family of "sensors" of foreign and endogenous signals.

    Science.gov (United States)

    Nebert, Daniel W

    2017-07-01

    The basic-helix/loop/helix per-Arnt-sim (bHLH/PAS) family comprises many transcription factors, found throughout all three kingdoms of life; bHLH/PAS members "sense" innumerable intracellular and extracellular "signals" - including endogenous compounds, foreign chemicals, gas molecules, redox potential, photons (light), gravity, heat, and osmotic pressure. These signals then initiate downstream signaling pathways involved in responding to that signal. The term "PAS", abbreviation for "per-Arnt-sim" was first coined in 1991. Although the mouse Arnt gene was not identified until 1991, evidence of its co-transcriptional binding partner, aryl hydrocarbon receptor (AHR), was first reported in 1974 as a "sensor" of foreign chemicals, up-regulating cytochrome P450 family 1 (CYP1) and other enzyme activities that usually metabolize the signaling chemical. Within a few years, AHR was proposed also to participate in inflammation. The mouse [Ah] locus was shown (1973-1989) to be relevant to chemical carcinogenesis, mutagenesis, toxicity and teratogenesis, the mouse Ahr gene was cloned in 1992, and the first Ahr(-/-) knockout mouse line was reported in 1995. After thousands of studies from the early 1970s to present day, we now realize that AHR participates in dozens of signaling pathways involved in critical-life processes, affecting virtually every organ and cell-type in the animal, including many invertebrates. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. G-CSF receptor truncations found in SCN/AML relieve SOCS3-controlled inhibition of STAT5 but leave suppression of STAT3 intact

    NARCIS (Netherlands)

    J. Gits (Judith); L.H.J. Aarts (Bart); C. Heijmans-Antonissen (Claudia); I.P. Touw (Ivo); G.J.M. van de Geijn (Gert-Jan)

    2004-01-01

    textabstractTruncated granulocyte colony-stimulating factor receptors (G-CSF-Rs) are implicated in severe congenital neutropenia (SCN) and the consecutive development of acute myeloid leukemia (AML). Mice expressing G-CSF-R truncation mutants (gcsfr-d715) show defective receptor

  2. The maintenance of cisplatin- and paclitaxel-induced mechanical and cold allodynia is suppressed by cannabinoid CB₂ receptor activation and independent of CXCR4 signaling in models of chemotherapy-induced peripheral neuropathy.

    Science.gov (United States)

    Deng, Liting; Guindon, Josée; Vemuri, V Kiran; Thakur, Ganesh A; White, Fletcher A; Makriyannis, Alexandros; Hohmann, Andrea G

    2012-09-22

    Chemotherapeutic agents produce dose-limiting peripheral neuropathy through mechanisms that remain poorly understood. We previously showed that AM1710, a cannabilactone CB₂ agonist, produces antinociception without producing central nervous system (CNS)-associated side effects. The present study was conducted to examine the antinociceptive effect of AM1710 in rodent models of neuropathic pain evoked by diverse chemotherapeutic agents (cisplatin and paclitaxel). A secondary objective was to investigate the potential contribution of alpha-chemokine receptor (CXCR4) signaling to both chemotherapy-induced neuropathy and CB₂ agonist efficacy. AM1710 (0.1, 1 or 5 mg/kg i.p.) suppressed the maintenance of mechanical and cold allodynia in the cisplatin and paclitaxel models. Anti-allodynic effects of AM1710 were blocked by the CB₂ antagonist AM630 (3 mg/kg i.p.), but not the CB1 antagonist AM251 (3 mg/kg i.p.), consistent with a CB₂-mediated effect. By contrast, blockade of CXCR4 signaling with its receptor antagonist AMD3100 (10 mg/kg i.p.) failed to attenuate mechanical or cold hypersensitivity induced by either cisplatin or paclitaxel. Moreover, blockade of CXCR4 signaling failed to alter the anti-allodynic effects of AM1710 in the paclitaxel model, further suggesting distinct mechanisms of action. Our results indicate that activation of cannabinoid CB₂ receptors by AM1710 suppresses both mechanical and cold allodynia in two distinct models of chemotherapy-induced neuropathic pain. By contrast, CXCR4 signaling does not contribute to the maintenance of chemotherapy-induced established neuropathy or efficacy of AM1710. Our studies suggest that CB₂ receptors represent a promising therapeutic target for the treatment of toxic neuropathies produced by cisplatin and paclitaxel chemotherapeutic agents.

  3. The maintenance of cisplatin- and paclitaxel-induced mechanical and cold allodynia is suppressed by cannabinoid CB2 receptor activation and independent of CXCR4 signaling in models of chemotherapy-induced peripheral neuropathy

    Directory of Open Access Journals (Sweden)

    Deng Liting

    2012-09-01

    Full Text Available Abstract Background Chemotherapeutic agents produce dose-limiting peripheral neuropathy through mechanisms that remain poorly understood. We previously showed that AM1710, a cannabilactone CB2 agonist, produces antinociception without producing central nervous system (CNS-associated side effects. The present study was conducted to examine the antinociceptive effect of AM1710 in rodent models of neuropathic pain evoked by diverse chemotherapeutic agents (cisplatin and paclitaxel. A secondary objective was to investigate the potential contribution of alpha-chemokine receptor (CXCR4 signaling to both chemotherapy-induced neuropathy and CB2 agonist efficacy. Results AM1710 (0.1, 1 or 5 mg/kg i.p. suppressed the maintenance of mechanical and cold allodynia in the cisplatin and paclitaxel models. Anti-allodynic effects of AM1710 were blocked by the CB2 antagonist AM630 (3 mg/kg i.p., but not the CB1 antagonist AM251 (3 mg/kg i.p., consistent with a CB2-mediated effect. By contrast, blockade of CXCR4 signaling with its receptor antagonist AMD3100 (10 mg/kg i.p. failed to attenuate mechanical or cold hypersensitivity induced by either cisplatin or paclitaxel. Moreover, blockade of CXCR4 signaling failed to alter the anti-allodynic effects of AM1710 in the paclitaxel model, further suggesting distinct mechanisms of action. Conclusions Our results indicate that activation of cannabinoid CB2 receptors by AM1710 suppresses both mechanical and cold allodynia in two distinct models of chemotherapy-induced neuropathic pain. By contrast, CXCR4 signaling does not contribute to the maintenance of chemotherapy-induced established neuropathy or efficacy of AM1710. Our studies suggest that CB2 receptors represent a promising therapeutic target for the treatment of toxic neuropathies produced by cisplatin and paclitaxel chemotherapeutic agents.

  4. Altered thyroxin and retinoid metabolic response to 2,3,7,8-tetrachlorodibenzo-p-dioxin in aryl hydrocarbon receptor-null mice

    Energy Technology Data Exchange (ETDEWEB)

    Nishimura, Noriko; Yonemoto, Junzo [National Institute for Environmental Studies, Endocrine Disruptors and Dioxin Research Project, Tsukuba (Japan); Miyabara, Yuichi [Shinshu University, Research and Education Center for Inlandwater Environment, Nagano (Japan); Fujii-Kuriyama, Yoshiaki [University of Tsukuba, Center for Tsukuba Advanced Research Alliance, Tsukuba (Japan); Tohyama, Chiharu [National Institute for Environmental Studies, Environmental Health Sciences Division, Tsukuba (Japan)

    2005-05-01

    To determine whether the disruption of thyroid hormone and retinoid homeostasis that occurs after exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) can be mediated by the arylhydrocarbon receptor (AhR), pregnant AhR-heterozygous (AhR+/-) mice were administered a single oral dose of 10 {mu}g kg{sup -1} TCDD at gestation day 12.5. Serum and liver were collected on postnatal day 21 from vehicle-treated control or TCDD-treated AhR+/- and AhR-null (AhR-/-) mouse pups. Whereas TCDD exposure resulted in a marked reduction of total thyroxin (TT4) and free T4 (FT4) levels in the serum of AhR+/- mice, TCDD had no effects on AhR-/- mice. Gene expression of UDP-glucuronosyltransferase (UGT)1A6, cytochrome P450 (CYP)1A1, and CYP1A2 in the liver was induced markedly by TCDD in AhR+/- but not AhR-/- mice. Induction of CYP1A1 in response to TCDD was confirmed by immunohistochemical evidence in that CYP1A1 protein was conspicuously localized in the cytoplasm of hepatocytes in the centrilobular region. Levels of retinyl palmitate were greatly reduced in the liver of TCDD-exposed AhR+/- mice, but not in vehicle-treated AhR+/- mice. No effects of TCDD on retinoid levels in the liver were found in AhR-/- mice. We conclude that disruption of thyroid hormone and retinoid homeostasis is mediated entirely via AhR. Induction of UGT1A6 is thought to be responsible at least partly for reduced serum thyroid hormone levels in TCDD-exposed mice. (orig.)

  5. Suppressed Belief

    Directory of Open Access Journals (Sweden)

    Komarine Romdenh-Romluc

    2009-12-01

    Full Text Available Moran’s revised conception of conscious belief requires us to reconceptualise suppressed belief. The work of Merleau-Ponty offers a way to do this. His account of motor-skills allows us to understand suppressed beliefs as pre-reflective ways of dealing with the world.

  6. 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

    Energy Technology Data Exchange (ETDEWEB)

    Karman, Bethany N., E-mail: bklement@illinois.edu; Basavarajappa, Mallikarjuna S., E-mail: mbshivapur@gmail.com; Craig, Zelieann R., E-mail: zelieann@illinois.edu; Flaws, Jodi A., E-mail: jflaws@illinois.edu

    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.

  7. The inhibition effect of 2,3,7,8-tetrachlorinated dibenzo-p-dioxin-induced aryl hydrocarbon receptor activation in human hepatoma cells with the treatment of cadmium chloride

    Energy Technology Data Exchange (ETDEWEB)

    Chao, How-Ran [Department of Environmental Science and Engineering, National Pingtung University of Science and Technology, Neipu, Pingtung 912, Taiwan (China); Emerging Compounds Research Center, National Pingtung University of Science and Technology, Neipu, Pingtung 912, Taiwan (China); Tsou, Tsui-Chun [Division of Environmental Health and Occupational Medicine, National Health Research Institutes, Zhunan, Miaoli 350, Taiwan (China); Chen, Hung-Ta [Sustainable Environment Research Center, National Cheng Kung University, Tainan 701, Taiwan (China); Chang, Eddy Essen; Tsai, Feng-Yuan [Division of Environmental Health and Occupational Medicine, National Health Research Institutes, Zhunan, Miaoli 350, Taiwan (China); Lin, Ding-Yan [Department of Environmental Science and Engineering, National Pingtung University of Science and Technology, Neipu, Pingtung 912, Taiwan (China); Chen, Fu-An [Graduate Institute of Pharmaceutical Science, Department of Pharmacy, Tajen University, Yan-Pu, Pingtung 907, Taiwan (China); Wang, Ya-Fen, E-mail: yfwang@cycu.edu.tw [Department of Bioenvironmental Engineering, Chung Yuan Christian University, Chungli, Taoyuan 320, Taiwan (China); R and D Center of Membrane Technology, Chung Yuan Christian University, Chungli 320, Taiwan (China)

    2009-10-15

    Polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs), considered as endocrine disruptors, tend to accumulate in fatty tissues. Dioxin-responsive element chemical activated luciferase gene expression assay (DRE-luciferase assay) has been recognized as a semi-quantitative method for screening dioxins for its fast and low-cost as compared with HRGC/HRMS. However, some problems with the bioassay, including specificity, detection variation resulted from different cleanup strategies, and uncertainty of false-negative or false-positive results, remain to be overcome. Cadmium is a prevalent environmental contaminant around the world. This study was aimed to examine the effects of cadmium on the 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-induced activation of aryl hydrocarbon receptor (AhR)-mediated gene expression in human hepatoma cells (Huh7-DRE-Luc cells and Huh7 cells). Ethoxyresorufin-O-deethylase (EROD) and DRE-luciferase assay were employed to determine the enzyme activity of cytochrome P450 1A1 (CYP1A1) and activation of AhR, respectively. The results showed that Cd{sup 2+} levels significantly inhibited the induction of TCDD-induced CYP1A1 and DRE luciferase activation in hepatoma cells. The 50% inhibited concentrations (IC{sub 50}) of CdCl{sub 2} were 0.414 {mu}M (95% confidence interval (C.I.): 0.230-0.602 {mu}M) in Huh7-DRE-Luc cells and 23.2 {mu}M (95% C.I.: 21.7-25.4 {mu}M) in Huh7 cells. Accordingly, prevention of interference with non-dioxin-like compounds in a DRE-luciferase assay is of great importance in an extensive cleanup procedure.

  8. Thraustochytrid protists degrade hydrocarbons

    Digital Repository Service at National Institute of Oceanography (India)

    Raikar, M.T.; Raghukumar, S.; Vani, V.; David, J.J.; Chandramohan, D.

    that thraustochytrids have the capability to utilize a wide range of organic nitrogen and carbon compounds for their nutrition. However, the capability of these protists to degrade hydrocarbons has not been examined so far. Hydrocarbons occur in seawater either... chromatography. (1) Gravimetry: Tarballs were extracted from experimental flasks with 10 ml of carbon tetrachloride, the extract transferred to pre- weighed Petri dish and the solvent allowed to RAIKAR et al.: THRAUSTOCHYTRID PROTISTS DEGRADE HYDROCARBONS...

  9. Growth of Murine Splenic Tissue Is Suppressed by Lymphotoxin β-Receptor Signaling (LTβR) Originating from Splenic and Non-Splenic Tissues

    DEFF Research Database (Denmark)

    Milićević, Novica M; Nohroudi, Klaus; Schmidt, Friederike

    2016-01-01

    splenic tissue. The suppressive activity positively correlated with the total number of LTβR expressing cells in the animal (regenerate weights of 115 ± 8 mg in LTβR deficient recipients and of 12 ± 9 mg in wild-type recipients), affected also developed splenic tissue, and was induced but not executed via....... By using splenic tissue transplantation it is possible to analyze a potential contribution of LTβR signaling inside and outside of the implanted tissue. We show that LTβR signaling within the endogenous spleen and within non-splenic tissues both significantly suppressed the regeneration of implanted...

  10. Activation of AMP-activated protein kinase rapidly suppresses multiple pro-inflammatory pathways in adipocytes including IL-1 receptor-associated kinase-4 phosphorylation

    DEFF Research Database (Denmark)

    Mancini, Sarah J; White, Anna D; Bijland, Silvia

    2017-01-01

    tissue from AMPKα1(-/-) mice exhibited increased JNK and STAT3 phosphorylation, supporting suppression of these distinct proinflammatory pathways by AMPK in vivo. The inhibition of multiple pro-inflammatory signalling pathways by AMPK may underlie the reported beneficial effects of AMPK activation...

  11. Thought suppression.

    Science.gov (United States)

    Wenzlaff, R M; Wegner, D M

    2000-01-01

    Although thought suppression is a popular form of mental control, research has indicated that it can be counterproductive, helping assure the very state of mind one had hoped to avoid. This chapter reviews the research on suppression, which spans a wide range of domains, including emotions, memory, interpersonal processes, psychophysiological reactions, and psychopathology. The chapter considers the relevant methodological and theoretical issues and suggests directions for future research.

  12. Hydrocarbon Spectral Database

    Science.gov (United States)

    SRD 115 Hydrocarbon Spectral Database (Web, free access)   All of the rotational spectral lines observed and reported in the open literature for 91 hydrocarbon molecules have been tabulated. The isotopic molecular species, assigned quantum numbers, observed frequency, estimated measurement uncertainty and reference are given for each transition reported.

  13. Estrogen receptor beta and 2-arachydonoylglycerol mediate the suppressive effects of estradiol on frequency of postsynaptic currents in gonadotropin-releasing hormone neurons of metestrous mice: an acute slice electrophysiological study

    Directory of Open Access Journals (Sweden)

    Flóra eBálint

    2016-03-01

    Full Text Available Gonadotropin-releasing hormone (GnRH neurons are controlled by 17β-estradiol (E2 contributing to the steroid feedback regulation of the reproductive axis. In rodents, E2 exerts a negative feedback effect upon GnRH neurons throughout the estrus-diestrus phase of the ovarian cycle. The present study was undertaken to reveal the role of estrogen receptor subtypes in the mediation of the E2 signal and elucidate the downstream molecular machinery of suppression. The effect of E2 administration at low physiological concentration (10 pM on GnRH neurons in acute brain slices obtained from metestrous GnRH-GFP mice was studied under paradigms of blocking or activating estrogen receptor subtypes and interfering with retrograde 2-arachydonoylglycerol (2-AG signaling. Whole-cell patch clamp recordings revealed that E2 significantly diminished the frequency of spontaneous postsynaptic currents (sPSCs in GnRH neurons (49. 62±7.6% which effect was abolished by application of the ERα/β blocker Faslodex (1 µM. Pretreatment of the brain slices with cannabinoid receptor type 1 (CB1 inverse agonist AM251 (1 µM and intracellularly applied endocannabinoid synthesis blocker THL (10 µM significantly attenuated the effect of E2 on the sPSCs. E2 remained effective in the presence of TTX indicating a direct action of E2 on GnRH cells. The ERβ specific agonist DPN (10 pM also significantly decreased the frequency of miniature postsynaptic currents (mPSCs in GnRH neurons. In addition, the suppressive effect of E2 was completely blocked by the selective ERβ antagonist PHTPP (1 µM indicating that ERβ is required for the observed rapid effect of the E2. In contrast, the ERα agonist PPT (10 pM or the membrane-associated G protein-coupled estrogen receptor (GPR30 agonist G1 (10 pM had no significant effect on the frequency of mPSCs in these neurons. AM251 and THL significantly abolished the effect of E2 whereas AM251 eliminated the action of DPN on the mPSCs. These

  14. Apelin protects against NMDA-induced retinal neuronal death via an APJ receptor by activating Akt and ERK1/2, and suppressing TNF-α expression in mice

    Directory of Open Access Journals (Sweden)

    Yuki Ishimaru

    2017-01-01

    Full Text Available Glutamate excitotoxicity mediated by N-methyl-d-aspartate (NMDA receptors is an important cause of retinal ganglion cell death in glaucoma. To elucidate whether apelin protects against retinal neuronal cell death, we examined protective effects of exogenous and endogenous apelin on neuronal cell death induced by intravitreal injection of NMDA in the retinas of mice. An intravitreal injection of NMDA induced neuronal cell death in both the retinal ganglion cell layer and inner nuclear layer, and reduced the amplitudes of scotopic threshold response (STR in electroretinography studies. Both cell death and STR amplitudes decrease induced by NMDA were prevented by a co-injection of [Pyr1]-apelin-13, and were facilitated by apelin deficiency. The neuroprotective effects of [Pyr1]-apelin-13 were blocked by an apelin receptor APJ antagonist, and by inhibitors of Akt and extracellular signal-regulated kinase 1/2 signaling pathways. Additionally, an intravitreal injection of tumor necrosis factor-α (TNF-α neutralizing antibody prevented NMDA-induced retinal neuronal cell death, and exogenous and endogenous apelin suppressed NMDA-induced upregulation of TNF-α in the retina. These results suggest that apelin protects neuronal cells against NMDA-induced death via an APJ receptor in the retina, and that apelin may have beneficial effects in the treatment of glaucoma.

  15. Plant hydrocarbon recovery process

    Energy Technology Data Exchange (ETDEWEB)

    Dzadzic, P.M.; Price, M.C.; Shih, C.J.; Weil, T.A.

    1982-01-26

    A process for production and recovery of hydrocarbons from hydrocarbon-containing whole plants in a form suitable for use as chemical feedstocks or as hydrocarbon energy sources which process comprises: (A) pulverizing by grinding or chopping hydrocarbon-containing whole plants selected from the group consisting of euphorbiaceae, apocynaceae, asclepiadaceae, compositae, cactaceae and pinaceae families to a suitable particle size, (B) drying and preheating said particles in a reducing atmosphere under positive pressure (C) passing said particles through a thermal conversion zone containing a reducing atmosphere and with a residence time of 1 second to about 30 minutes at a temperature within the range of from about 200* C. To about 1000* C., (D) separately recovering the condensable vapors as liquids and the noncondensable gases in a condition suitable for use as chemical feedstocks or as hydrocarbon fuels.

  16. Plasma devices for hydrocarbon reformation

    KAUST Repository

    Cha, Min Suk

    2017-02-16

    Plasma devices for hydrocarbon reformation are provided. Methods of using the devices for hydrocarbon reformation are also provided. The devices can include a liquid container to receive a hydrocarbon source, and a plasma torch configured to be submerged in the liquid. The plasma plume from the plasma torch can cause reformation of the hydrocarbon. The device can use a variety of plasma torches that can be arranged in a variety of positions in the liquid container. The devices can be used for the reformation of gaseous hydrocarbons and/or liquid hydrocarbons. The reformation can produce methane, lower hydrocarbons, higher hydrocarbons, hydrogen gas, water, carbon dioxide, carbon monoxide, or a combination thereof.

  17. HDL activation of endothelial sphingosine-1-phosphate receptor-1 (S1P1) promotes regeneration and suppresses fibrosis in the liver

    DEFF Research Database (Denmark)

    Ding, Bi-Sen; Liu, Catherine H; Sun, Yue

    2016-01-01

    Regeneration of hepatic sinusoidal vasculature is essential for non-fibrotic liver regrowth and restoration of its metabolic capacity. However, little is known about how this specialized vascular niche is regenerated. Here we show that activation of endothelial sphingosine-1-phosphate receptor-1 (S...

  18. Notch3 Maintains Luminal Phenotype and Suppresses Tumorigenesis and Metastasis of Breast Cancer via Trans-Activating Estrogen Receptor

    NARCIS (Netherlands)

    Dou, Xiao-Wei; Liang, Yuan-Ke; Lin, Hao-Yu; Wei, Xiao-Long; Zhang, Yong-Qu; Bai, Jing-Wen; Chen, Chun-Fa; Chen, Min; Du, Cai-Wen; Li, Yao-Chen; Tian, Jie; Man, Kwan; Zhang, Guo-Jun

    2017-01-01

    The luminal A phenotype is the most common breast cancer subtype and is characterized by estrogen receptor α expression (ERα). Identification of the key regulator that governs the luminal phenotype of breast cancer will clarify the pathogenic mechanism and provide novel therapeutic strategies for

  19. Behavioral Deficits and Subregion-Specific Suppression of LTP in Mice Expressing a Population of Mutant NMDA Receptors throughout the Hippocampus

    Science.gov (United States)

    Chen, Philip E.; Errington, Michael L.; Kneussel, Matthias; Chen, Guiquan; Annala, Alexander J.; Rudhard, York H.; Rast, Georg F.; Specht, Christian G.; Tigaret, Cezar M.; Nassar, Mohammed A.; Morris, Richard G.M.; Bliss, Timothy V. P.; Schoepfer, Ralf

    2009-01-01

    The NMDA receptor (NMDAR) subunit GluN1 is an obligatory component of NMDARs without a known functional homolog and is expressed in almost every neuronal cell type. The NMDAR system is a coincidence detector with critical roles in spatial learning and synaptic plasticity. Its coincidence detection property is crucial for the induction of…

  20. Short-hairpin RNA-induced suppression of adenine nucleotide translocase-2 in breast cancer cells restores their susceptibility to TRAIL-induced apoptosis by activating JNK and modulating TRAIL receptor expression

    Directory of Open Access Journals (Sweden)

    Kim Chul-Woo

    2010-09-01

    Full Text Available Abstract Background Tumor necrosis factor (TNF-related apoptosis-inducing ligand (TRAIL; apo2 ligand induces apoptosis in cancer cells but has little effect on normal cells. However, many cancer cell types are resistant to TRAIL-induced apoptosis, limiting the clinical utility of TRAIL as an anti-cancer agent. We previously reported that the suppression of adenine nucleotide translocase-2 (ANT2 by short-hairpin RNA (shRNA induces apoptosis of breast cancer cells, which frequently express high levels of ANT2. In the present study, we examined the effect of RNA shRNA-induced suppression of ANT2 on the resistance of breast cancer cells to TRAIL-induced apoptosis in vitro and in vivo. Results ANT2 shRNA treatment sensitized MCF7, T47 D, and BT474 cells to TRAIL-induced apoptosis by up-regulating the expression of TRAIL death receptors 4 and 5 (DR4 and DR5 and down-regulating the TRAIL decoy receptor 2 (DcR2. In MCF7 cells, ANT2 knockdown activated the stress kinase c-Jun N-terminal kinase (JNK, subsequently stabilizing and increasing the transcriptional activity of p53 by phosphorylating it at Thr81; it also enhanced the expression and activity of DNA methyltransferase 1 (DNMT1. ANT2 shRNA-induced overexpression of DR4/DR5 and TRAIL sensitization were blocked by a p53 inhibitor, suggesting that p53 activation plays an important role in the transcriptional up-regulation of DR4/DR5. However, ANT2 knockdown also up-regulated DR4/DR5 in the p53-mutant cell lines BT474 and T47 D. In MCF7 cells, ANT2 shRNA treatment led to DcR2 promoter methylation and concomitant down-regulation of DcR2 expression, consistent with the observed activation of DNMT1. Treatment of the cells with a demethylating agent or JNK inhibitor prevented the ANT2 shRNA-induced down-regulation of DcR2 and activation of both p53 and DNMT1. In in vivo experiments using nude mice, ANT2 shRNA caused TRAIL-resistant MCF7 xenografts to undergo TRAIL-induced cell death, up-regulated DR4/DR5

  1. Characterization of hydrocarbon utilizing fungi from hydrocarbon ...

    African Journals Online (AJOL)

    Prof. Ogunji

    Microorganisms play diverse roles in biotechnology; one of such roles is ... hydrocarbon polluted sites using vapour phase transfer technique with ... The purified fungal isolates were identified based on .... Cytochrome P450 monooxygenase systems which incorporate molecular .... substrate specificity on marine bacteria.

  2. Metformin inhibits 7,12-dimethylbenz[a]anthracene-induced breast carcinogenesis and adduct formation in human breast cells by inhibiting the cytochrome P4501A1/aryl hydrocarbon receptor signaling pathway

    Energy Technology Data Exchange (ETDEWEB)

    Maayah, Zaid H. [Department of Pharmacology and Toxicology, College of Pharmacy, King Saud University, Riyadh 11451 (Saudi Arabia); Ghebeh, Hazem [Stem Cell & Tissue Re-Engineering, King Faisal Specialist Hospital and Research Center, Riyadh 11211 (Saudi Arabia); Alhaider, Abdulqader A. [Department of Pharmacology and Toxicology, College of Pharmacy, King Saud University, Riyadh 11451 (Saudi Arabia); Camel Biomedical Research Unit, College of Pharmacy and Medicine, King Saud University, Riyadh 11451 (Saudi Arabia); El-Kadi, Ayman O.S. [Faculty of Pharmacy & Pharmaceutical Sciences, University of Alberta, Edmonton (Canada); Soshilov, Anatoly A.; Denison, Michael S. [Department of Environmental Toxicology, University of California at Davis, Davis, CA 95616 (United States); Ansari, Mushtaq Ahmad [Department of Pharmacology and Toxicology, College of Pharmacy, King Saud University, Riyadh 11451 (Saudi Arabia); Korashy, Hesham M., E-mail: hkorashy@ksu.edu.sa [Department of Pharmacology and Toxicology, College of Pharmacy, King Saud University, Riyadh 11451 (Saudi Arabia)

    2015-04-15

    Recent studies have established that metformin (MET), an oral anti-diabetic drug, possesses antioxidant activity and is effective against different types of cancer in several carcinogen-induced animal models and cell lines. However, whether MET can protect against breast cancer has not been reported before. Therefore, the overall objectives of the present study are to elucidate the potential chemopreventive effect of MET in non-cancerous human breast MCF10A cells and explore the underlying mechanism involved, specifically the role of cytochrome P4501A1 (CYP1A1)/aryl hydrocarbon receptor (AhR) pathway. Transformation of the MCF10A cells into initiated breast cancer cells with DNA adduct formation was conducted using 7,12-dimethylbenz[a]anthracene (DMBA), an AhR ligand. The chemopreventive effect of MET against DMBA-induced breast carcinogenesis was evidenced by the capability of MET to restore the induction of the mRNA levels of basic excision repair genes, 8-oxoguanine DNA glycosylase (OGG1) and apurinic/apyrimidinic endonuclease1 (APE1), and the level of 8-hydroxy-2-deoxyguanosine (8-OHdG). Interestingly, the inhibition of DMBA-induced DNA adduct formation was associated with proportional decrease in CYP1A1 and in NAD(P)H:quinone oxidoreductase 1 (NQO1) gene expression. Mechanistically, the involvements of AhR and nuclear factor erythroid 2-related factor-2 (Nrf2) in the MET-mediated inhibition of DMBA-induced CYP1A1 and NQO1 gene expression were evidenced by the ability of MET to inhibit DMBA-induced xenobiotic responsive element and antioxidant responsive element luciferase reporter gene expression which suggests an AhR- and Nrf2-dependent transcriptional control. However, the inability of MET to bind to AhR suggests that MET is not an AhR ligand. In conclusion, the present work shows a strong evidence that MET inhibits the DMBA-mediated carcinogenicity and adduct formation by inhibiting the expression of CYP1A1 through an AhR ligand-independent mechanism

  3. Omeprazole induces NAD(P)H quinone oxidoreductase 1 via aryl hydrocarbon receptor-independent mechanisms: Role of the transcription factor nuclear factor erythroid 2–related factor 2

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Shaojie; Patel, Ananddeep; Moorthy, Bhagavatula; Shivanna, Binoy, E-mail: shivanna@bcm.edu

    2015-11-13

    Activation of the aryl hydrocarbon receptor (AhR) transcriptionally induces phase I (cytochrome P450 (CYP) 1A1) and phase II (NAD(P)H quinone oxidoreductase 1 (NQO1) detoxifying enzymes. The effects of the classical and nonclassical AhR ligands on phase I and II enzymes are well studied in human hepatocytes. Additionally, we observed that the proton pump inhibitor, omeprazole (OM), transcriptionally induces CYP1A1 in the human adenocarcinoma cell line, H441 cells via AhR. Whether OM activates AhR and induces the phase II enzyme, NAD(P)H quinone oxidoreductase 1 (NQO1), in fetal primary human pulmonary microvascular endothelial cells (HPMEC) is unknown. Therefore, we tested the hypothesis that OM will induce NQO1 in HPMEC via the AhR. The concentrations of OM used in our experiments did not result in cytotoxicity. OM activated AhR as evident by increased CYP1A1 mRNA expression. However, contrary to our hypothesis, OM increased NQO1 mRNA and protein via an AhR-independent mechanism as AhR knockdown failed to abrogate OM-mediated increase in NQO1 expression. Interestingly, OM activated Nrf2 as evident by increased phosphoNrf2 (S40) expression in OM-treated compared to vehicle-treated cells. Furthermore, Nrf2 knockdown abrogated OM-mediated increase in NQO1 expression. In conclusion, we provide evidence that OM induces NQO1 via AhR-independent, but Nrf2-dependent mechanisms. - Highlights: • We investigated whether omeprazole induces NQO1 in human fetal lung cells. • Omeprazole induces the phase II enzyme, NQO1, in human fetal lung cells. • AhR deficiency fails to abrogate omeprazole-mediated induction of NQO1. • Omeprazole increases phosphoNrf2 (S40) protein expression in human fetal lung cells. • Nrf2 knockdown abrogates the induction of NQO1 by omeprazole in human lung cells.

  4. Craniofacial form is altered by chronic adult exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD in Han/Wistar and Long–Evans rats with different aryl hydrocarbon receptor (AhR structures

    Directory of Open Access Journals (Sweden)

    Sabrina B. Sholts

    2015-01-01

    Full Text Available Mammalian bone has shown a variety of responses to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD exposure in experimental and wildlife studies. Although many responses have been well characterized in the postcranial skeleton, dioxin-induced effects on the cranium are largely unknown. In this study, we investigated the effects of chronic adult exposure to TCDD on cranial size and shape in dioxin-resistant Han/Wistar (H/W and dioxin-sensitive Long–Evans (L–E rat strains. Three-dimensional landmark configurations for the face, vault, and base of the cranium were recorded and analyzed using geometric morphometrics (GM and dose–response modeling. The strongest effects were shown by L–E and H/W rats with daily exposures of 100 and 1000 ng TCDD/kg bw/day, respectively, resulting in significant reductions in centroid size (CS in all three cranial modules for both strains except for the vault in H/W rats. Consistent with previous evidence of intraspecific variation in TCDD resistance, the benchmark doses (CEDs for cranial size reduction in L–E rats were roughly 10-fold lower than those for H/W rats. For both strains, the face showed the greatest size reduction from the highest doses of TCDD (i.e., 3.6 and 6.3% decreases in H/W and L–E rats, respectively, most likely related to dose-dependent reductions in limb bone size and body weight gain. However, intrinsic morphological differences between strains were also observed: although the control groups of H/W and L–E rats had vaults and bases of comparable size, the face was 6.4% larger in L–E rats. Thus, although H/W rats possess an altered aryl hydrocarbon receptor (AhR that appears to mediate and provides some resistance to TCDD exposure, their smaller reductions in facial size may also relate to strain-specific patterns of cranial development and growth. Future research will be aimed at understanding how ontogenetic factors may modulate toxic effects of prenatal and lactational exposure on

  5. Interocular suppression

    Science.gov (United States)

    Tuna, Ana Rita; Almeida Neves Carrega, Filipa; Nunes, Amélia Fernandes

    2017-08-01

    The objective of this work is to quantify the suppressive imbalance, based on the manipulation of ocular luminance, between a group of subjects with normal binocular vision and a group of subjects with amblyopia. The result reveals that there are statistically significant differences in interocular dominance between two groups, evidencing a greater suppressive imbalance in amblyopic subjects. The technique used, proved to be a simple, easy to apply and economic method, for quantified ocular dominance. It is presented as a technique with the potential to accompany subjects with a marked dominance in one of the eyes that makes fusion difficult.

  6. Toll-like receptor 7 governs interferon and inflammatory responses to rhinovirus and is suppressed by IL-5-induced lung eosinophilia

    OpenAIRE

    Hatchwell, Luke; Collison, Adam; Girkin, Jason; Parsons, Kristy; Li, Junyao; Zhang, Jie; Phipps, Simon; Knight, Darryl; Bartlett, Nathan W; Johnston, Sebastian L; Foster, Paul S; Wark, Peter A B; Mattes, Joerg

    2015-01-01

    Background Asthma exacerbations represent a significant disease burden and are commonly caused by rhinovirus (RV), which is sensed by Toll-like receptors (TLR) such as TLR7. Some asthmatics have impaired interferon (IFN) responses to RV, but the underlying mechanisms of this clinically relevant observation are poorly understood. Objectives To investigate the importance of intact TLR7 signalling in vivo during RV exacerbation using mouse models of house dust mite (HDM)-induced allergic airways...

  7. 25(OH) vitamin D suppresses macrophage adhesion and migration by downregulation of ER stress and scavenger receptor A1 in type 2 diabetes.

    Science.gov (United States)

    Riek, Amy E; Oh, Jisu; Darwech, Isra; Moynihan, Clare E; Bruchas, Robin R; Bernal-Mizrachi, Carlos

    2014-10-01

    Cardiovascular disease (CVD) is the leading cause of mortality in patients with type 2 diabetes mellitus (T2DM). Vitamin D deficiency is not only more prevalent in diabetics but also doubles the risk of developing CVD. However, it is unknown whether 25-hydroxy vitamin D [25(OH)D3] replacement slows monocyte adhesion and migration, critical mechanisms involved in atherosclerosis progression. In this study, monocytes from vitamin D-deficient diabetic patients were cultured either in the patient's serum or in vitamin D-deficient media with or without 25(OH)D3 treatment. Adding 25(OH)D3 to monocytes cultured in vitamin D-deficient serum or media decreased monocyte adhesion to fibronectin and migration stimulated by monocyte chemotactic protein 1 (MCP-1). Accordingly, 25(OH)D3 decreased adhesion marker β1- and β2-integrin expression and migration receptor chemokine (C-C motif) receptor 2 (CCR2) expression. 25(OH)D3 treatment downregulated monocyte endoplasmic reticulum (ER) stress and scavenger receptor class A, type 1 (SR-A1) expression. The absence of SR-A1 prevented the increased macrophage adhesion and migration induced by vitamin D deficiency. Moreover, the absence of SR-A1 prevented the induction of adhesion and migration and expression of their associated membrane receptors by Thapsigargin, an ER stress inducer. These results identify cellular activation of monocyte/macrophage vitamin D signaling through 25(OH)D3 as a potential mechanism that could modulate adhesion and migration in diabetic subjects. This article is part of a Special Issue entitled '16th Vitamin D Workshop'. Copyright © 2013 Elsevier Ltd. All rights reserved.

  8. Allopregnanolone suppresses diabetes-induced neuropathic pain and motor deficit through inhibition of GABAA receptor down-regulation in the spinal cord of diabetic rats

    Directory of Open Access Journals (Sweden)

    Samira Afrazi

    2014-05-01

    Full Text Available Objective(s:Painful diabetic neuropathy is associated with hyperexcitability and hyperactivity of spinal cord neurons. However, its underlying pathophysiological mechanisms have not been fully clarified. Induction of excitatory/inhibitory neurotransmission imbalance at the spinal cord seems to account for the abnormal neuronal activity in diabetes. Protective properties of neurosteroids have been demonstrated in numerous cellular and animal models of neurodegeneration. Materials and Methods: Here, the protective effects of allopregnanolone, a neurosteroid were investigated in an in vivo model of diabetic neuropathy. The tail-flick test was used to assess the nociceptive threshold. Diabetes was induced by injection of 50 mg/kg (IP streptozotocin. Seven weeks after the induction of diabetes, the dorsal half of the lumbar spinal cord was assayed for the expression of γ2 subunit of GABAA receptor using semiquantitative RT-PCR. Results: The data shows that allopregnanolone (5 and 20 mg/kg markedly ameliorated diabetes-induced thermal hyperalgesia and motor deficit. The weights of diabetic rats that received 5 and 20 mg/kg allopregnanolone did not significantly reduce during the time course of study. Furthermore, this neurosteroid could inhibit GABAA receptor down-regulation induced by diabetes in the rat spinal cord. Conclusion: The data revealed that allopregnanolone has preventive effects against hyperglycemic-induced neuropathic pain and motor deficit which are related to the inhibition of GABAA receptor down-regulation.

  9. Repeated administration of aripiprazole produces a sensitization effect in the suppression of avoidance responding and phencyclidine-induced hyperlocomotion and increases D2 receptor-mediated behavioral function.

    Science.gov (United States)

    Gao, Jun; Qin, Rongyin; Li, Ming

    2015-04-01

    The present study investigated how repeated administration of aripiprazole (a novel antipsychotic drug) alters its behavioral effects in two behavioral tests of antipsychotic activity and whether this alteration is correlated with an increase in dopamine D2 receptor function. Male adult Sprague-Dawley rats were first repeatedly tested with aripiprazole (3, 10 and 30 mg/kg, subcutaneously (sc)) or vehicle in a conditioned avoidance response (CAR) test or a phencyclidine (PCP) (3.20 mg/kg, sc)-induced hyperlocomotion test daily for five consecutive days. After 2-3 days of drug-free retraining or resting, all rats were then challenged with aripiprazole (1.5 or 3.0 mg/kg, sc). Repeated administration of aripiprazole progressively increased its inhibition of avoidance responding and PCP-induced hyperlocomotion. More importantly, rats previously treated with aripiprazole showed significantly lower avoidance response and lower PCP-induced hyperlocomotion than those previously treated with vehicle in the challenge tests. An increased sensitivity to quinpirole (a selective D2/3 agonist) in prior aripiprazole-treated rats was also found in the quinpirole-induced hyperlocomotion test, suggesting an enhanced D2/3-mediated function. These findings suggest that aripiprazole, despite its distinct receptor mechanisms of action, induces a sensitization effect similar to those induced by other antipsychotic drugs and this effect may be partially mediated by brain plasticity involving D2/3 receptor systems. © The Author(s) 2014.

  10. Repeated pre-treatment with antihistamines suppresses [corrected] transcriptional up-regulations of histamine H(1) receptor and interleukin-4 genes in toluene-2,4-diisocyanate-sensitized rats.

    Science.gov (United States)

    Mizuguchi, Hiroyuki; Hatano, Masaya; Matsushita, Chiyo; Umehara, Hayato; Kuroda, Wakana; Kitamura, Yoshiyuki; Takeda, Noriaki; Fukui, Hiroyuki

    2008-12-01

    Antihistamines are effective for treatment of seasonal nasal allergy. Recently, prophylactic treatment with antihistamines in patients with pollinosis was reported to be more effective when started before the pollen season. The administration with antihistamines from 2 to 6 weeks before onset of the pollen season is recommended for management of allergic rhinitis in Japan. To determine the reason for the effectiveness of prophylactic treatment with antihistamines, the effects of repeated pre-treatment with antihistamines before provocation with toluene 2,4-diisocyanate (TDI) on their nasal allergy-like behavior and up-regulations of histamine H(1) receptors (H1R) and interleukin (IL)-4 mRNAs in their nasal mucosa were examined. Provocation with TDI induced sneezing and up-regulations of H1R and IL-4 mRNAs in the nasal mucosa of TDI-sensitized rats. Repeated pre-treatments with antihistamines including epinastine, olopatadine, or d-chlorpheniramine for 1 to 5 weeks before provocation with TDI suppressed TDI-induced sneezing and the up-regulations of H1R and IL-4 mRNAs in the nasal mucosa more than their administrations once or for 3 days before TDI provocation. Our data indicate that repeated pre-treatment with antihistamines before provocation with TDI is more effective than their single treatment in reducing nasal allergy-like behavior by causing additional suppression of up-regulations of H1R and IL-4 mRNAs in the nasal mucosa.

  11. Suppression of microRNA-16 protects against acute myocardial infarction by reversing beta2-adrenergic receptor down-regulation in rats.

    Science.gov (United States)

    Liu, Jiaqi; Sun, Fei; Wang, Yuying; Yang, Wanqi; Xiao, Hongwen; Zhang, Yue; Lu, Renzhong; Zhu, Haixia; Zhuang, Yuting; Pan, Zhenwei; Wang, Zhiguo; Du, Zhimin; Lu, Yanjie

    2017-03-21

    microRNA-16 (miR-16) has been shown to be up-regulated in ischemic heart. Beta2-adrenoreceptor (β2-AR) exerts cardioprotective property in ischemic injury. This study aims to determine the effect of miR-16 in cardiac injury in rats and the possible involvement of β2-AR in this process. Acute myocardial infarction (AMI) model in rats was induced by ligation of left coronary artery. Neonatal rat ventricular cells (NRVCs) were cultured in vitro tests. The cardiomyocyte model of oxidative injury was mimicked by hydrogen peroxide. The expression of miR-16 was obviously up-regulated and β2-AR was remarkably down-regulated in both AMI rats and NRVCs under oxidative stress. miR-16 over-expression in NRVCs reduced cell viability and increased apoptosis. Conversely, inhibition of endogenous miR-16 with its specific inhibitor reversed these changes. Over-expression of miR-16 using an miR-16 lentivirus in AMI rats markedly increased cardiac infarct area, lactate dehydrogenase and creatine kinase activity, and exacerbated cardiac dysfunction. Lentivirus-mediated knockdown of miR-16 alleviated acute cardiac injury. Moreover, miR-16 over-expression significantly suppressed β2-AR protein expression in both cultured NRVCs and AMI rats, while inhibition of miR-16 displayed opposite effect on β2-AR protein expression. Luciferase assay confirmed that miR-16 could directly target the 3'untranslated region of β2-AR mRNA. miR-16 is detrimental to the infarct heart and suppression of miR-16 protects rat hearts from ischemic injury via up-regulating of β2-AR by binding to the 3'untranslated region of β2-AR gene. This study indicates that targeting miR-16/β2-AR axis may be a promising strategy for ischemic heart disease.

  12. Suppression of acute and chronic cardiac allograft rejection in mice by inhibition of chemokine receptor 5 in combination with cyclosporine A.

    Science.gov (United States)

    Li, Jun; Xia, Jiahong; Zhang, Kailun; Xu, Lei

    2009-11-01

    Inhibition of chemokine receptor 5 (CCR5), a chemokine receptor expressed on activated T cells, is an effective antiviral therapy in patients with HIV infection, but its efficacy in modulating inflammation and immunity is only just beginning to be investigated. In this study we examined the inhibition of CCR5 in combination with the treatment with cyclosporine A in acute and chronic rejection in cardiac transplantation. Eighty fully MHC-mismatched murine cardiac allograft models were randomized to four groups. Recipients in group A were treated with anti-CCR5 mAb and CsA, mice in group B were given anti-CCR5 mAb alone, animals in group C were administered only CsA, and group D were the control group with PBS. Acute and chronic rejection was investigated on day 7 and day 45 post-transplant, respectively. Allografts treated with anti-CCR5 mAb plus CsA showed significantly prolonged survival (44.73 +/- 0.258 d, P cardiac graft failure that has not been obviated by conventional immunosuppressive agents.

  13. Nimesulide, a cyclooxygenase-2 selective inhibitor, suppresses obesity-related non-alcoholic fatty liver disease and hepatic insulin resistance through the regulation of peroxisome proliferator-activated receptor γ.

    Science.gov (United States)

    Tsujimoto, Shunsuke; Kishina, Manabu; Koda, Masahiko; Yamamoto, Yasutaka; Tanaka, Kohei; Harada, Yusuke; Yoshida, Akio; Hisatome, Ichiro

    2016-09-01

    Cyclooxygenase (COX)-2 selective inhibitors suppress non-alcoholic fatty liver disease (NAFLD); however, the precise mechanism of action remains unknown. The aim of this study was to examine how the COX-2 selective inhibitor nimesulide suppresses NAFLD in a murine model of high-fat diet (HFD)‑induced obesity. Mice were fed either a normal chow diet (NC), an HFD, or HFD plus nimesulide (HFD-nime) for 12 weeks. Body weight, hepatic COX-2 mRNA expression and triglyceride accumulation were significantly increased in the HFD group. Triglyceride accumulation was suppressed in the HFD-nime group. The mRNA expression of hepatic peroxisome proliferator-activated receptor γ (PPARγ) and the natural PPARγ agonist 15-deoxy-Δ12,14-prostaglandin J2 (15d‑PGJ2) were significantly increased in the HFD group and significantly suppressed in the HFD-nime group. Glucose metabolism was impaired in the HFD group compared with the NC group, and it was significantly improved in the HFD-nime group. In addition, the plasma insulin levels in the HFD group were increased compared with those in the NC group, and were decreased in the HFD-nime group. These results indicate that HFD-induced NAFLD is mediated by the increased hepatic expression of COX-2. We suggest that the production of 15d-PGJ2, which is mediated by COX-2, induces NAFLD and hepatic insulin resistance by activating PPARγ. Furthermore, the mRNA expression of tissue inhibitor of metalloproteinases-1 (TIMP‑1), procollagen-1 and monocyte chemoattractant protein-1 (MCP-1), as well as the number of F4/80-positive hepatic (Kupffer) cells, were significantly increased in the HFD group compared with the NC group, and they were reduced by nimesulide. In conclusion, COX-2 may emerge as a molecular target for preventing the development of NAFLD and insulin resistance in diet-related obesity.

  14. C3a receptor antagonist ameliorates inflammatory and fibrotic signals in type 2 diabetic nephropathy by suppressing the activation of TGF-β/smad3 and IKBα pathway.

    Directory of Open Access Journals (Sweden)

    Ling Li

    Full Text Available OBJECTIVE: Diabetic nephropathy (DN is a serious complication for patients with diabetes mellitus (DM. Emerging evidence suggests that complement C3a is involved in the progression of DN. The aim of this study was to investigate the effect of C3a Receptor Agonist (C3aRA on DN and its potential mechanism of action in rats with type 2 diabetes mellitus (T2DM. METHODS: T2DM was induced in SD rats by a high fat diet (HFD plus repeated low dose streptozocin (STZ injections. T2DM rats were treated with vehicle or C3aRA for 8 weeks. Biochemical analysis, HE and PAS stains were performed to evaluate the renal function and pathological changes. Human renal glomerular endothelial cells (HRGECs were cultured and treated with normal glucose (NG, high glucose (HG, HG+C3a, HG+C3a+C3aRA and HG+C3a+BAY-11-7082 (p-IKBα Inhibitor or SIS3 (Smad3 Inhibitor, respectively. Real-time PCR, immunofluorescent staining and western blot were performed to detect the mRNA and protein levels, respectively. RESULTS: T2DM rats showed worse renal morphology and impaired renal function compared with control rats, including elevated levels of serum creatinine (CREA, blood urea nitrogen (BUN and urine albumin excretion (UACR, as well as increased levels of C3a, C3aR, IL-6, p-IKBα, collagen I, TGF-β and p-Smad3 in the kidney of T2DM rats and C3a-treated HRGECs. In contrast, C3aRA treatment improved renal function and morphology, reduced CREA, UACR and the intensity of PAS and collagen I staining in the kidney of T2DM rats, and decreased C3a, p-IKBα, IL-6, TGF-β, p-Smad3 and collagen I expressions in HRGECs and T2DM rats. CONCLUSION: C3a mediated pro-inflammatory and pro-fibrotic responses and aggravated renal injury in T2DM rats. C3aRA ameliorated T2DN by inhibiting IKBα phosphorylation and cytokine release, and also TGF-β/Smad3 signaling and ECM deposition. Therefore, complement C3a receptor is a potential therapeutic target for DN.

  15. Inosine, an Endogenous Purine Nucleoside, Suppresses Immune Responses and Protects Mice from Experimental Autoimmune Encephalomyelitis: a Role for A2A Adenosine Receptor.

    Science.gov (United States)

    Junqueira, Stella Célio; Dos Santos Coelho, Igor; Lieberknecht, Vicente; Cunha, Mauricio Peña; Calixto, João B; Rodrigues, Ana Lúcia S; Santos, Adair Roberto Soares; Dutra, Rafael Cypriano

    2017-07-01

    Multiple sclerosis (MS) is a T cell autoimmune, inflammatory, and demyelinating disease of the central nervous system (CNS). Currently available therapies have partially effective actions and numerous side reactions. Inosine, an endogenous purine nucleoside, has immunomodulatory, neuroprotective, and analgesic properties. Herein, we evaluated the effect of inosine on the development and progression of experimental autoimmune encephalomyelitis (EAE), an experimental model of MS. Inosine (1 or 10 mg/kg, i.p.) was administrated twice a day for 40 days. Immunological and inflammatory responses were evaluated by behavioral, histological, immunohistochemical, ELISA, RT-PCR, and Western blotting analysis. The administration of inosine exerted neuroprotective effects against EAE by diminishing clinical signs, including thermal and mechanical hyperalgesia, as well as weight loss typical of the disease. These beneficial effects of inosine seem to be associated with the blockade of inflammatory cell entry into the CNS, especially lymphocytes, thus delaying the demyelinating process and astrocytes activation. In particular, up-regulation of IL-17 levels in the secondary lymphoid tissues, a result of EAE, was prevented by inosine treatment in EAE mice. Additionally, inosine consistently prevented A2AR up-regulation in the spinal cord, likely, through an ERK1-independent pathway. Altogether, these results allow us to propose that this endogenous purine might be a putative novel and helpful tool for the prevention of autoimmune and neurodegenerative diseases, such as MS. Thus, inosine could have considerable implications for future therapies of MS, and this study may represent the starting point for further investigation into the role of inosine and adenosinergic receptors in neuroinflammation processes. Graphical Abstract Preventive treatment with inosine inhibits the development and progression of EAE in C57Bl/6 mice. Furthermore, neuroinflammation and demyelinating processes

  16. Fructose-1,6-bisphosphate suppresses lipopolysaccharide-induced expression of ICAM-1 through modulation of toll-like receptor-4 signaling in brain endothelial cells.

    Science.gov (United States)

    Seok, Sun Mi; Park, Tae Yeop; Park, Hye-Si; Baik, Eun Joo; Lee, Soo Hwan

    2015-05-01

    Fructose-1,6-bisphosphate (FBP) is a glycolytic intermediate with salutary effects in various brain injury models, but its neuroprotective mechanism is incompletely understood. In this study, we examined the effects of FBP on the expression of adhesion molecules in cerebrovascular endothelial cells and explored the possible mechanisms therein involved. FBP significantly down-regulated lipopolysaccharide (LPS)-induced expression of adhesion molecules and leukocyte adhesion to brain endothelial cells and inhibited NF-κB activity, which is implicated in the expression of adhesion molecules. FBP abrogated ICAM-1 expression and NF-κB activation induced by macrophage-activating lipopeptide 2-kDa (MALP-2) or overexpression of MyD88 or TRAF6. FBP suppressed TRAF6-induced phosphorylation of TAK1, IKKβ and IκBα, but fail to affect NF-κB activity induced by ectopic expression of IKKβ. In addition, LPS-induced IRAK-1 phosphorylation was inhibited by FBP, suggesting the presence of multiple molecular targets of FBP in MyD88-dependent signaling pathway. FBP significantly attenuated ICAM-1 expression and NF-κB activity induced by poly[I:C] or overexpression of TRIF or TBK1. FBP significantly repressed the expression of interferon-β (IFN-β) and the activation of IFN regulatory factor 3 (IRF3) induced by LPS, poly[I:C] or overexpression of TRIF or TBK1, but fail to affect IRF3 activity induced by ectopic expression of constitutively active IRF3. Overall, our results demonstrate that FBP modulates both MyD88- and TRIF-dependent signaling pathways of TLR4 and subsequent inflammatory responses in brain endothelial cells, providing insight into its neuroprotective mechanism in brain injury associated with inflammation. Copyright © 2015 Elsevier B.V. All rights reserved.

  17. Inhibition of lectin-like oxidized low-density lipoprotein receptor-1 reduces cardiac fibroblast proliferation by suppressing GATA Binding Protein 4

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Bin; Liu, Ning-Ning; Liu, Wei-Hua; Zhang, Shuang-Wei; Zhang, Jing-Zhi; Li, Ai-Qun [Department of Cardiology, The Second Affiliated Hospital of Guangzhou Medical University, Guangzhou (China); Guangzhou Institute of Cardiovascular Disease, Guangzhou (China); Liu, Shi-Ming, E-mail: gzliushiming@126.com [Department of Cardiology, The Second Affiliated Hospital of Guangzhou Medical University, Guangzhou (China); Guangzhou Institute of Cardiovascular Disease, Guangzhou (China)

    2016-07-08

    Lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) and GATA Binding Protein 4 (GATA4) are important for the growth of cardiac fibroblasts (CFs). When deregulated, LOX-1 and GATA4 can cause cardiac remodeling. In the present study, we found novel evidence that GATA4 was required for the LOX-1 regulation of CF proliferation. The inhibition of LOX-1 by RNA interference LOX-1 lentivirus resulted in the loss of PI3K/Akt activation and GATA4 protein expression. The overexpression of LOX-1 by lentivirus rescued CF proliferation, PI3K/Akt activation, and GATA4 protein expression. Moreover, GATA4 overexpression enhanced CF proliferation with LOX-1 inhibition. We also found that the inhibition of PI3K/Akt activation by LY294002, a PI3K inhibitor, reduced cell proliferation and protein level of GATA4. In summary, GATA4 may play an important role in the LOX-1 and PI3K/Akt regulation of CF proliferation. -- Highlights: •GATA4 is regulated by LOX-1 signaling in CFs. •GATA4 is involved in LOX-1 regulating CF proliferation. •GATA4 is regulated by PI3K/Akt signaling in CFs.

  18. Zbtb16 (PLZF) is stably suppressed and not inducible in non-innate T cells via T cell receptor-mediated signaling.

    Science.gov (United States)

    Zhang, Sai; Laouar, Amale; Denzin, Lisa K; Sant'Angelo, Derek B

    2015-07-16

    The transcription factor PLZF (promyelocytic leukemia zinc finger; zbtb16) is essential for nearly all of the unique characteristics of NKT cells including their rapid and potent response to antigen. In the immune system, zbtb16 expression is only found in innate cells. Conventional T cells that ectopically express PLZF spontaneously acquire an activated, effector phenotype. Activation induced expression of lineage defining transcription factors such as T-bet, FoxP3, RORγt, GATA3 and others is essential for naïve T cell differentiation into effector T cells. In this study, we used sensitive genetic-based approaches to assess the induction of PLZF expression in non-innate T cells by T cell receptor (TCR)-mediated activation. Surprisingly, we found that PLZF was stably repressed in non-innate T cells and that TCR-mediated signaling was not sufficient to induce PLZF in conventional T cells. The inactivated state of PLZF was stably maintained in mature T cells, even under inflammatory conditions imposed by bacterial infection. Collectively, our data show that, in contrast to multiple recent reports, PLZF expression is highly specific to innate T cells and cannot be induced in conventional T cells via TCR-mediated activation or inflammatory challenge.

  19. Endocannabinoid CB1 Receptor Mediated Rises in Ca2+ and Depolarization-Induced Suppression of Inhibition within the Laterodorsal Tegmental Nucleus

    DEFF Research Database (Denmark)

    Soni, Neeraj; Kohlmeier, Kristi Anne

    2016-01-01

    Cannabinoid type 1 receptors (CB1Rs) are functionally active within the laterodorsal tegmental nucleus (LDT), which is critically involved in control of rapid eye movement sleep, cortical arousal, and motivated states. To further characterize the cellular consequences of activation of CB1Rs...... in this nucleus, we examined whether CB1R activation led to rises in intracellular Ca(2+) ([Ca(2+)]i) and whether processes shown in other regions to involve endocannabinoid (eCB) transmission were present in the LDT. Using a combination of Ca(2+) imaging in multiple cells loaded with Ca(2+) imaging dye via 'bulk......-loading' or in single cells loaded with dye via a patch-clamp electrode, we found that WIN 55212-2 (WIN-2), a potent CB1R agonist, induced increases in [Ca(2+)]i which were sensitive to AM251, a CB1R antagonist. A proportion of rises persisted in TTX and/or low-extracellular Ca(2+) conditions. Attenuation...

  20. Differential and additive suppressive effects of 5-HT3 (palonosetron)- and NK1 (netupitant)-receptor antagonists on cisplatin-induced vomiting and ERK1/2, PKA and PKC activation.

    Science.gov (United States)

    Darmani, Nissar A; Zhong, Weixia; Chebolu, Seetha; Mercadante, Frank

    2015-04-01

    To better understand the anti-emetic profile of the 5-HT3 (palonosetron)- and the tachykinin NK1 (netupitant) -receptor antagonists, either alone or in combination, we evaluated the effects of palonosetron and/or netupitant pretreatment on cisplatin-evoked vomiting and changes in the phosphorylation of brainstem kinases such as the extracellular signal-regulated protein kinases 1 and 2 (ERK1/2), protein kinase C alpha/beta (PKCα/β), and protein kinase A (PKA) in the least shrew. Our results demonstrate that cisplatin (10mg/kg, i.p.) causes emesis in the least shrew over 40h with respective peak early- and delayed-phases occurring at 1 - 2 and 32 - 34h post-injection. During the early phase (0 - 16h post cisplatin), palonosetron (0.1mg/kg, s.c.) significantly protected shrews from vomiting with a near complete suppression of vomit frequency. Palonosetron also significantly protected shrews from vomiting during the delayed phase (27 - 40h post cisplatin), but the reduction in mean vomit frequency failed to achieve significance. On the other hand, netupitant (5mg/kg, i.p.) totally abolished vomiting during the delayed phase, and tended to suppress the mean vomit frequency during the acute phase. The combined treatment protected shrews almost completely from vomiting during both phases. Brainstem pERK1/2 levels were significantly elevated at all time-points except at 40h post-cisplatin administration. PKA phosphorylation tended to be elevated throughout the delayed phase, but a significant increase only occurred at 33h. Brainstem pPKCα/β levels were enhanced during acute-phase with a significant elevation at 2h. Palonosetron, netupitant or their combination had no effect on elevated pERK1/2 levels during acute phase, but the combination reversed ERK1/2 phosphorylation at 33h post-cisplatin treatment. In addition, only the combined regimen prevented the cisplatin-induced PKCα/β phosphorylation observed at the acute phase. On the other hand, palonosetron and

  1. KiSS-1-mediated suppression of the invasive ability of human pancreatic carcinoma cells is not dependent on the level of KiSS-1 receptor GPR54

    Science.gov (United States)

    WANG, CHUN-HUI; QIAO, CHONG; WANG, RUO-CHEN; ZHOU, WEN-PING

    2016-01-01

    The onset of local invasion and lymphatic metastasis in pancreatic cancer limits survival following surgical intervention and additional therapies. Reduced expression of KiSS-1 in pancreatic cancer is associated with cancer metastasis. Previous studies have indicated that kisspeptin, the KiSS-1 peptide, is able to bind to its receptor-GPR54 (hOT7T175) and suppress the migration of PANC-1 pancreatic cancer cells. Whether the metastatic suppression of KiSS-1 is dependent on the levels of GPR54 in pancreatic cancer cell lines remains unclear. Human BxPC-3 pancreatic carcinoma cells are highly differentiated without exhibiting metastasis, however PANC-1 pancreatic carcinoma cells are poorly differentiated and exhibit local and lymph node metastasis. Compared with primary cultured trophoblasts, BxPc-3 and PANC-1 cells were observed to express low levels of KiSS-1 mRNA and protein, measured using reverse transcription-quantitative polymerase chain reaction and western blotting, respectively. However, greater mRNA and protein expression levels of GPR54 were observed in PANC-1 cells compared with BxPc-3 cells. An MTT assay was used to investigate the effect of KiSS-1 on BxPc-3 and PANC-1 cell proliferation. There were no significant differences in proliferation following transfection with KiSS-1 in BxPc-3 and PANC-1 cells compared with the controls (P>0.05). A Transwell assay with chambers coated with Matrigel was used to evaluate the in vitro invasive ability of BxPc-3 and PANC-1 cells, with the invasion index of BxPc-3 and PANC-1 cells significantly reduced following 48 h of KiSS-1 overexpression (PGPR54 expression was not altered (P>0.05). KiSS-1 is a metastasis suppressor gene of pancreatic cancer, and this suppression is not dependent on the expression levels of GPR54. Therefore, KiSS-1 is potentially a novel target for gene therapy. PMID:26572251

  2. Ghrelin receptor (GHS-R1A antagonism suppresses both alcohol consumption and the alcohol deprivation effect in rats following long-term voluntary alcohol consumption.

    Directory of Open Access Journals (Sweden)

    Petra Suchankova

    Full Text Available Alcohol dependence is a heterogeneous disorder where several signalling systems play important roles. Recent studies implicate that the gut-brain hormone ghrelin, an orexigenic peptide, is a potential mediator of alcohol related behaviours. Ghrelin increases whereas a ghrelin receptor (GHS-R1A antagonist decreases alcohol consumption as well as operant self-administration of alcohol in rodents that have consumed alcohol for twelve weeks. In the present study we aimed at investigating the effect of acute and repeated treatment with the GHS-R1A antagonist JMV2959 on alcohol intake in a group of rats following voluntarily alcohol consumption for two, five and eight months. After approximately ten months of voluntary alcohol consumption the expression of the GHS-R1A gene (Ghsr as well as the degree of methylation of a CpG island found in Ghsr was examined in reward related brain areas. In a separate group of rats, we examined the effect of the JMV2959 on alcohol relapse using the alcohol deprivation paradigm. Acute JMV2959 treatment was found to decrease alcohol intake and the effect was more pronounced after five, compared to two months of alcohol exposure. In addition, repeated JMV2959 treatment decreased alcohol intake without inducing tolerance or rebound increase in alcohol intake after the treatment. The GHS-R1A antagonist prevented the alcohol deprivation effect in rats. There was a significant down-regulation of the Ghsr expression in the ventral tegmental area (VTA in high- compared to low-alcohol consuming rats after approximately ten months of voluntary alcohol consumption. Further analysis revealed a negative correlation between Ghsr expression in the VTA and alcohol intake. No differences in methylation degree were found between high- compared to low-alcohol consuming rats. These findings support previous studies showing that the ghrelin signalling system may constitute a potential target for development of novel treatment strategies

  3. PSD95 suppresses dendritic arbor development in mature hippocampal neurons by occluding the clustering of NR2B-NMDA receptors.

    Directory of Open Access Journals (Sweden)

    Fernando J Bustos

    Full Text Available Considerable evidence indicates that the NMDA receptor (NMDAR subunits NR2A and NR2B are critical mediators of synaptic plasticity and dendritogenesis; however, how they differentially regulate these processes is unclear. Here we investigate the roles of the NR2A and NR2B subunits, and of their scaffolding proteins PSD-95 and SAP102, in remodeling the dendritic architecture of developing hippocampal neurons (2-25 DIV. Analysis of the dendritic architecture and the temporal and spatial expression patterns of the NMDARs and anchoring proteins in immature cultures revealed a strong positive correlation between synaptic expression of the NR2B subunit and dendritogenesis. With maturation, the pruning of dendritic branches was paralleled by a strong reduction in overall and synaptic expression of NR2B, and a significant elevation in synaptic expression of NR2A and PSD95. Using constructs that alter the synaptic composition, we found that either over-expression of NR2B or knock-down of PSD95 by shRNA-PSD95 augmented dendritogenesis in immature neurons. Reactivation of dendritogenesis could also be achieved in mature cultured neurons, but required both manipulations simultaneously, and was accompanied by increased dendritic clustering of NR2B. Our results indicate that the developmental increase in synaptic expression of PSD95 obstructs the synaptic clustering of NR2B-NMDARs, and thereby restricts reactivation of dendritic branching. Experiments with shRNA-PSD95 and chimeric NR2A/NR2B constructs further revealed that C-terminus of the NR2B subunit (tail was sufficient to induce robust dendritic branching in mature hippocampal neurons, and suggest that the NR2B tail is important in recruiting calcium-dependent signaling proteins and scaffolding proteins necessary for dendritogenesis.

  4. The saponin D39 blocks dissociation of non-muscular myosin heavy chain IIA from TNF receptor 2, suppressing tissue factor expression and venous thrombosis.

    Science.gov (United States)

    Zhai, Ke-Feng; Zheng, Jin-Rong; Tang, You-Mei; Li, Fang; Lv, Yan-Ni; Zhang, Yuan-Yuan; Gao, Zhen; Qi, Jin; Yu, Bo-Yang; Kou, Jun-Ping

    2017-09-01

    Non-muscular myosin heavy chain IIA (NMMHC IIA) plays a key role in tissue factor expression and venous thrombosis. Natural products might inhibit thrombosis through effects on NMMHC IIA. Here, we have shown that a natural saponin, D39, from Liriope muscari exerted anti-thrombotic activity in vivo, by targeting NMMHC IIA. Expression and activity of tissue factor in endothelial cells were analysed in vitro by Western blot and simplified chromogenic assays. Interactions between D39 and NMMHC IIA were assessed by serial affinity chromatography and molecular docking analysis. D39-dependent interactions between NMMHC IIA and TNF receptor 2 (TNFR2) were measured by immunofluorescence, co-immunoprecipitation and proximity ligation assays. Anti-thrombotic activity of D39 in vivo was evaluated with a model of inferior vena cava ligation injury in mice. D39 inhibited tissue factor expression and procoagulant activities in HUVECs and decreased thrombus weight in inferior vena cava-ligated mice dose-dependently. Serial affinity chromatography and molecular docking analysis suggested that D39 bound to NMMHC IIA. In HEK293T cells, D39 inhibited tissue factor expression evoked by NMMHC IIA overexpression. This effect was blocked by NMMHC IIA knockdown in HUVECs. D39 inhibited dissociation of NMMHC IIA from TNFR2, which subsequently modulated the Akt/GSK3β-NF-κB signalling pathways. D39 inhibited tissue factor expression and thrombus formation by modulating the Akt/GSK3β and NF-κB signalling pathways through NMMHC IIA. We identified a new natural product that targeted NMMHC IIA, as a potential treatment for thrombotic disorders and other vasculopathies. © 2017 The British Pharmacological Society.

  5. Comparison of one-year outcomes following coronary artery stenting in diabetic versus nondiabetic patients (from the Enhanced Suppression of the Platelet IIb/IIIa Receptor With Integrilin Therapy [ESPRIT] Trial).

    Science.gov (United States)

    Labinaz, Marino; Madan, Mina; O'Shea, J O'Conor; Kilaru, Rakhi; Chin, Wai; Pieper, Karen; McGuire, Darren K; Saucedo, Jorge F; Talley, J David; Lui, Henry; Kitt, Michael M; Califf, Robert M; Tcheng, James T

    2002-09-15

    For patients undergoing nonurgent coronary stent implantation, blockade of the glycoprotein IIb/IIIa receptor with eptifibatide reduces the incidence of ischemic complications. We evaluated the interaction of eptifibatide with diabetes in patients who underwent this procedure by analyzing the 1-year outcomes of those enrolled in the Enhanced Suppression of the Platelet IIb/IIIa Receptor with Integrilin Therapy (ESPRIT) trial (466 diabetic and 1,595 nondiabetic patients). At 1 year, the composite end point of death, myocardial infarction (MI), or target vessel revascuarlization (TVR) was higher in diabetic patients (24.5% vs 18.4%; p = 0.008). At 1 year, eptifibatide had a similar effect on the composite end point of death, MI, or TVR in diabetic (hazards ratio [HR] 0.71, 95% confidence interval [CI] 0.49 to 1.04) and nondiabetic patients (HR 0.80, 95% CI 0.63 to 0.99). A similar treatment effect was also seen on death or MI in both groups. The 1-year mortality rate for diabetic patients assigned to placebo was 3.5% versus 1.3% for patients receiving eptifibatide (HR 0.37, 95% CI 0.10 to 1.41); the latter rate was similar to the mortality rate of 1.4% for nondiabetic patients in the eptifibatide group. However, eptifibatide did not have a significant effect on TVR in diabetic patients (HR 0.90, 95% CI 0.57 to 1.41). Our data suggest that treatment with eptifibatide is associated with a similar relative reduction in adverse ischemic complications in diabetic and nondiabetic patients undergoing coronary stent implantation. There is no evidence of a statistical interaction in the treatment effect of eptifibatide between patients with and without diabetes.

  6. Suppressed expression of homotypic multinucleation, extracellular domains of CD172α (SIRP-α) and CD47 (IAP) receptors in TAMs upregulated by Hsp70-peptide complex in Dalton's lymphoma.

    Science.gov (United States)

    Gautam, P K; Acharya, A

    2014-07-01

    CD172α and CD47 are members of glycoprotein expressed on macrophages and various immune cells, promote immune recognition and T cell stimulation that priming phagocytosis of pathogens and apoptotic bodies and malignant cell. Tumour-releasing immunosuppressive factor promotes tumour growth and transforms the tumour resident M1 phenotype of macrophage to M2 phenotype (TAMs) that promotes tumour progression by downregulating the expression of different surface receptor including CD172α and CD47. Recent studies have reported that CD172α and CD47 are involved in the pathogenesis and promote malignancies such as lymphoma, leukaemia, melanoma, lung cancer and multiple myeloma, and their expression varies during infection and malignancies. Autologous Hsp70 is well recognized for its role in activating macrophages leading to enhance production of inflammatory cytokines. It has been observed that Hsp70 derived from normal tissues do not elicit tumour immunity, while Hsp70 preparation from tumour cell was able to elicit tumour immunity. However, the role of exogenous autologous hsp70 on the formation of giant cells is completely unknown. Therefore, in the present study, we sought to investigate the effect of Hsp70-peptide complex on the expression of CD172α and CD47 receptors in normal peritoneal macrophages (NMO) and TAMs. Finding shows that the expression of CD172α and CD47 enhances in TAMs and it reverts back the suppressed function of TAMs into M1 state of immunoregulatory phenotype that promotes tumour regression by enhanced multinucleation and phagocytosis of malignant cells and significantly enhances the homotypic fusion of macrophages and polykaryon formation in vitro by enhancing the expression of SIRPα and IAP. © 2014 John Wiley & Sons Ltd.

  7. HYDROCARBON PROSPECTING OVE DROCARBON ...

    African Journals Online (AJOL)

    eobe

    e trapping configurations of the faults mbedding shale were presumed to be the creation of multiple reservoir of hydrocarbon bearing formations one horizon to the other and. (Figure 2). The vertical f the major and subsidiary growth t the amount of throw of both major s are small and varied from line to line survey but ...

  8. Nitric Oxide-Releasing Aspirin Suppresses NF-κB Signaling in Estrogen Receptor Negative Breast Cancer Cells in Vitro and in Vivo

    Directory of Open Access Journals (Sweden)

    Niharika Nath

    2015-07-01

    Full Text Available Estrogen receptor negative (ER(− breast cancer is aggressive, responds poorly to current treatments and has a poor prognosis. The NF-κB signaling pathway is implicated in ER(− tumorigenesis. Aspirin (ASA is chemopreventive against ER(+ but not for ER(− breast cancers. Nitric oxide-releasing aspirin (NO-ASA is a safer ASA where ASA is linked to an NO-releasing moiety through a spacer. In vitro, we investigated anti-proliferation effects of NO-ASA (para- and meta-isomers against ER(− breast cancer cells MDA-MB-231 and SK-BR-23, effects on NF-κB signaling, and reactive oxygen species by standard techniques. In vivo, effects of NO-ASA were evaluated in a mouse xenograft model using MDA-MB-231 cells. p-NO-ASA inhibited the growth of MDA-MB-231 and SK-BR-3 cells at 24 h, the respective IC50s were 13 ± 2 and 17 ± 2 μM; ASA had an IC50 of >3000 μM in both cell lines. The IC50s for m-NO-ASA in MDA-MB-231 and SK-BR-3 were 173 ± 15 and 185 ± 12 μM, respectively, therefore, implying p-NO-ASA as a stronger inhibitor of growth p-NO-ASA reduced cell growth by inhibiting proliferation, inducing apoptosis and causing G0/G1 cell cycle block. Activation of NF-κB was inhibited by both isomers as demonstrated by decreases in NF-κB-DNA binding and luciferase activity at 24 h, However, m-NO-ASA produced transient effects at 3 h such as increased NF-κB-DNA-binding, increased levels of nuclear p50, even though both isomers inhibited IκB degradation. Increase in nuclear p50 by m-NO-ASA was associated with translocation of p50 in to the nucleus as observed by immunoflouresence at 3 h. NO-ASA induced reactive oxygen species (ROS as evidenced by overall increases in both H2DCFDA (2′,7′-dichlorodihydrofluorescein and DHE (dihydroethidium-derived fluorescence. Inhibition of ROS by N-acetyl-cysteine reversed the m-NO-ASA-mediated translocation of p50 in to the nucleus. In xenografts, p-NO-ASA inhibited tumor growth by inhibiting proliferation (PCNA and

  9. Nitric Oxide-Releasing Aspirin Suppresses NF-κB Signaling in Estrogen Receptor Negative Breast Cancer Cells in Vitro and in Vivo.

    Science.gov (United States)

    Nath, Niharika; Chattopadhyay, Mitali; Rodes, Deborah B; Nazarenko, Anna; Kodela, Ravinder; Kashfi, Khosrow

    2015-07-09

    Estrogen receptor negative (ER(-)) breast cancer is aggressive, responds poorly to current treatments and has a poor prognosis. The NF-κB signaling pathway is implicated in ER(-) tumorigenesis. Aspirin (ASA) is chemopreventive against ER(+) but not for ER(-) breast cancers. Nitric oxide-releasing aspirin (NO-ASA) is a safer ASA where ASA is linked to an NO-releasing moiety through a spacer. In vitro, we investigated anti-proliferation effects of NO-ASA (para- and meta-isomers) against ER(-) breast cancer cells MDA-MB-231 and SK-BR-23, effects on NF-κB signaling, and reactive oxygen species by standard techniques. In vivo, effects of NO-ASA were evaluated in a mouse xenograft model using MDA-MB-231 cells. p-NO-ASA inhibited the growth of MDA-MB-231 and SK-BR-3 cells at 24 h, the respective IC50s were 13 ± 2 and 17 ± 2 μM; ASA had an IC50 of >3000 μM in both cell lines. The IC50s for m-NO-ASA in MDA-MB-231 and SK-BR-3 were 173 ± 15 and 185 ± 12 μM, respectively, therefore, implying p-NO-ASA as a stronger inhibitor of growth p-NO-ASA reduced cell growth by inhibiting proliferation, inducing apoptosis and causing G0/G1 cell cycle block. Activation of NF-κB was inhibited by both isomers as demonstrated by decreases in NF-κB-DNA binding and luciferase activity at 24 h, However, m-NO-ASA produced transient effects at 3 h such as increased NF-κB-DNA-binding, increased levels of nuclear p50, even though both isomers inhibited IκB degradation. Increase in nuclear p50 by m-NO-ASA was associated with translocation of p50 in to the nucleus as observed by immunoflouresence at 3 h. NO-ASA induced reactive oxygen species (ROS) as evidenced by overall increases in both H2DCFDA (2',7'-dichlorodihydrofluorescein) and DHE (dihydroethidium)-derived fluorescence. Inhibition of ROS by N-acetyl-cysteine reversed the m-NO-ASA-mediated translocation of p50 in to the nucleus. In xenografts, p-NO-ASA inhibited tumor growth by inhibiting proliferation (PCNA and tumor volume

  10. Hydrocarbon Deposition Attenuates Osteoblast Activity on Titanium

    Science.gov (United States)

    Hayashi, R.; Ueno, T.; Migita, S.; Tsutsumi, Y.; Doi, H.; Ogawa, T.; Hanawa, T.; Wakabayashi, N.

    2014-01-01

    Although the reported percentage of bone-implant contact is far lower than 100%, the cause of such low levels of bone formation has rarely been investigated. This study tested the negative biological effect of hydrocarbon deposition onto titanium surfaces, which has been reported to be inevitable. Osteogenic MC3T3-E1 cells were cultured on titanium disks on which the carbon concentration was experimentally regulated to achieve carbon/titanium (C/Ti) ratios of 0.3, 0.7, and 1.0. Initial cellular activities such as cell attachment and cell spreading were concentration-dependently suppressed by the amount of carbon on the titanium surface. The osteoblastic functions of alkaline phosphatase activity and calcium mineralization were also reduced by more than 40% on the C/Ti (1.0) surface. These results indicate that osteoblast activity is influenced by the degree of hydrocarbon contamination on titanium implants and suggest that hydrocarbon decomposition before implant placement may increase the biocompatibility of titanium. PMID:24868012

  11. Effect of operator and institutional volume on clinical outcomes after percutaneous coronary interventions performed in Canada and the United States: a brief report from the Enhanced Suppression of the Platelet glycoprotein IIb/IIIa Receptor with Integrilin Therapy (ESPRIT) study.

    Science.gov (United States)

    Madan, Mina; Nikhil, Janarthan; Hellkamp, Anne S; Pieper, Karen S; Labinaz, Marino; Cohen, E A; Buller, Christopher E; Cantor, Warren J; Seidelin, Peter; Ducas, John; Carere, Ronald G; Natarajan, Madhu K; O'Shea, J Conor; Tcheng, James E

    2009-08-01

    The Enhanced Suppression of the Platelet glycoprotein IIb/IIIa Receptor with Integrilin Therapy (ESPRIT) trial compared the use of eptifibatide with placebo in 2064 coronary intervention patients. It was previously reported that Canadian patients had reduced rates of 30-day and one-year death, myocardial infarction (MI) or target vessel revascularization (TVR) compared with patients in the United States (US). To examine whether operator or institutional volume differences explain the regional variation in clinical outcome. Each site received an operator and institutional volume survey. Fifty-seven sites (62%) returned complete data on 1338 patients. In this smaller cohort, Canadian patients had reduced rates of 30-day and one-year death, MI or TVR compared with US patients (6.3% versus 10.3% and 14.9% versus 20.1%, respectively; PESPRIT study, institutional volume was associated with a modest reduction in risk of death, MI or TVR over short- and long-term follow-up periods. The Canadian and US investigators and institutions selected in ESPRIT had similar annual procedural volumes. Therefore, volume variables did not explain the differential risk of clinical events observed for patients enrolled in the two countries.

  12. Microbial degradation of petroleum hydrocarbons.

    Science.gov (United States)

    Varjani, Sunita J

    2017-01-01

    Petroleum hydrocarbon pollutants are recalcitrant compounds and are classified as priority pollutants. Cleaning up of these pollutants from environment is a real world problem. Bioremediation has become a major method employed in restoration of petroleum hydrocarbon polluted environments that makes use of natural microbial biodegradation activity. Petroleum hydrocarbons utilizing microorganisms are ubiquitously distributed in environment. They naturally biodegrade pollutants and thereby remove them from the environment. Removal of petroleum hydrocarbon pollutants from environment by applying oleophilic microorganisms (individual isolate/consortium of microorganisms) is ecofriendly and economic. Microbial biodegradation of petroleum hydrocarbon pollutants employs the enzyme catalytic activities of microorganisms to enhance the rate of pollutants degradation. This article provides an overview about bioremediation for petroleum hydrocarbon pollutants. It also includes explanation about hydrocarbon metabolism in microorganisms with a special focus on new insights obtained during past couple of years. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Induction of murine NAD(P)H:quinone oxidoreductase by 2,3,7,8-tetrachlorodibenzo-p-dioxin requires the CNC (cap 'n' collar) basic leucine zipper transcription factor Nrf2 (nuclear factor erythroid 2-related factor 2): cross-interaction between AhR (aryl hydrocarbon receptor) and Nrf2 signal transduction.

    Science.gov (United States)

    Ma, Qiang; Kinneer, Krista; Bi, Yongyi; Chan, Jefferson Y; Kan, Yuet Wai

    2004-01-01

    TCDD (2,3,7,8-tetrachlorodibenzo- p -dixoin) induces phase II drug-metabolizing enzyme NQO1 [NAD(P)H:quinone oxidoreductase; EC 1.6.99.2; DT-diaphorase] in a wide range of mammalian tissues and cells. Here, we analysed the molecular pathway mediating NQO1 induction by TCDD in mouse hepatoma cells. Inhibition of protein synthesis with CHX (cycloheximide) completely blocks induction of NQO1 by TCDD as well as the basal expression and induction by phenolic antioxidant tBHQ (2-t-butylbenzene-1,4-diol), implicating a labile factor in NQO1 mRNA expression. The inhibition is both time- and concentration-dependent, requires inhibition of protein synthesis, and occurs at a transcriptional level. Inhibition of NQO1 transcription by CHX correlates with a rapid reduction of the CNC bZip (cap 'n' collar basic leucine zipper) transcription factor Nrf2 (nuclear factor erythroid 2-related factor 2) through the 26 S proteasome pathway. Moreover, blocking Nrf2 degradation with proteasome inhibitor MG132 increases the amount of Nrf2 and superinduces NQO1 in the presence of TCDD or tBHQ. Finally, genetic experiments using AhR (aryl hydrocarbon receptor)-, Arnt (aryl hydrocarbon receptor nuclear translocator)- or Nrf2-deficient cells reveal that, while induction of NQO1 by TCDD depends on the presence of AhR and Arnt, the basal and inducible expression of NQO1 by either TCDD or tBHQ requires functional Nrf2. The findings demonstrate a novel role of Nrf2 in the induction of NQO1 by TCDD and provide new insights into the mechanism by which Nrf2 regulates the induction of phase II enzymes by both phenolic antioxidants and AhR ligands.

  14. Toxicological effects of polycyclic aromatic hydrocarbons and their derivatives on respiratory cells

    Science.gov (United States)

    Koike, Eiko; Yanagisawa, Rie; Takano, Hirohisa

    2014-11-01

    Polycyclic aromatic hydrocarbons (PAHs) are found in ambient aerosols and particulate matter. Experimental studies have shown that PAHs and related chemicals can induce toxicological effects. The present study aimed to investigate the effects of PAHs and their derivatives on the respiratory and immune systems and the underlying mechanisms. The human bronchial epithelial cell line BEAS-2B was exposed to PAHs and their derivatives, and the cytotoxicity and proinflammatory protein expression were then investigated. A cytotoxic effect was observed in BEAS-2B exposed to PAH derivatives such as naphthoquinone (NQ), phenanthrenequinone (PQ), 1-nitropyrene (1-NP), and 1-aminopyrene (1-AP). In addition, 1,2-NQ and 9,10-PQ showed more effective cytotoxicity than 1,4-NQ and 1,4-PQ, respectively. Pyrene showed a weak cytotoxic effect. On the other hand, naphthalene and phenanthrene showed no significant effects. Pyrene, 1-NP, and 1-AP also increased intercellular adhesion molecule-1 expression and interleukin-6 production in BEAS-2B. The increase was partly suppressed by protein kinase inhibitors such as the epidermal growth factor receptor-selective tyrosine kinase inhibitor and nuclear receptor antagonists such as the thyroid hormone receptor antagonist. The present study suggests that the toxicological effects of chemicals may be related to the different activities resulting from their structures, such as numbers of benzene rings and functional groups. Furthermore, the chemical-induced increase in proinflammatory protein expression in bronchial epithelial cells was possibly a result of the activation of protein kinase pathways and nuclear receptors. The increase may partly contribute to the adverse health effects of atmospheric PAHs.

  15. Direct hydrocarbon fuel cells

    Science.gov (United States)

    Barnett, Scott A.; Lai, Tammy; Liu, Jiang

    2010-05-04

    The direct electrochemical oxidation of hydrocarbons in solid oxide fuel cells, to generate greater power densities at lower temperatures without carbon deposition. The performance obtained is comparable to that of fuel cells used for hydrogen, and is achieved by using novel anode composites at low operating temperatures. Such solid oxide fuel cells, regardless of fuel source or operation, can be configured advantageously using the structural geometries of this invention.

  16. THERMOCHEMISTRY OF HYDROCARBON RADICALS

    Energy Technology Data Exchange (ETDEWEB)

    Kent M. Ervin, Principal Investigator

    2004-08-17

    Gas phase negative ion chemistry methods are employed to determine enthalpies of formation of hydrocarbon radicals that are important in combustion processes and to investigate the dynamics of ion-molecule reactions. Using guided ion beam tandem mass spectrometry, we measure collisional threshold energies of endoergic proton transfer and hydrogen atom transfer reactions of hydrocarbon molecules with negative reagent ions. The measured reaction threshold energies for proton transfer yield the relative gas phase acidities. In an alternative methodology, competitive collision-induced dissociation of proton-bound ion-molecule complexes provides accurate gas phase acidities relative to a reference acid. Combined with the electron affinity of the R {center_dot} radical, the gas phase acidity yields the RH bond dissociation energy of the corresponding neutral molecule, or equivalently the enthalpy of formation of the R{center_dot} organic radical, using equation: D(R-H) = {Delta}{sub acid}H(RH) + EA(R) - IE(H). The threshold energy for hydrogen abstraction from a hydrocarbon molecule yields its hydrogen atom affinity relative to the reagent anion, providing the RH bond dissociation energy directly. Electronic structure calculations are used to evaluate the possibility of potential energy barriers or dynamical constrictions along the reaction path, and as input for RRKM and phase space theory calculations. In newer experiments, we have measured the product velocity distributions to obtain additional information on the energetics and dynamics of the reactions.

  17. Quercetin-3-O-glucronide inhibits noradrenaline binding to α2-adrenergic receptor, thus suppressing DNA damage induced by treatment with 4-hydroxyestradiol and noradrenaline in MCF-10A cells.

    Science.gov (United States)

    Yamazaki, Shunsuke; Sakakibara, Hiroyuki; Takemura, Hitomi; Yasuda, Michiko; Shimoi, Kayoko

    2014-09-01

    Risk factors for breast cancer include estrogens such as 17β-estradiol (E2) and high stress levels. 4-Hydroxyestradiol (4-OHE2), a metabolite of E2 formed preferentially by cytochrome P450 1B1, is oxidized to E2-3,4-quinone, which reacts with DNA to form depurinating adducts that exert genotoxicity and carcinogenicity. Endogenous catecholamines such as adrenaline (A) and noradrenaline (NA) are released from the adrenal gland and sympathetic nervous system during exposure to stress. Here, we found that treatment with 4-OHE2 (3 μM) and NA (3 nM) significantly induced the phosphorylation of histone H2AX (γ-H2AX), one of the earliest indicators of DNA damage, and apurinic (AP) sites via the α2-adrenergic receptor (α2-AR) in human mammary epithelial MCF-10A cells. As an inverse association between a higher intake of flavonoids and breast cancer risk has previously been suggested from epidemiological studies, we investigated the effects of quercetin-3-O-glucuronide (Q3G), a circulating metabolite of quercetin in the blood, on 4-OHE2- and NA-induced γ-H2AX and AP sites. Q3G (0.1 μM) suppressed their induction and inhibited the binding of [(3)H]-NA to α2-AR. These results suggest that Q3G acts as an α2-AR antagonist and that it could be used as a chemopreventive agent for stress-promoted breast cancer. Copyright © 2014 Elsevier Ltd. All rights reserved.

  18. Thermophysical Properties of Hydrocarbon Mixtures

    Science.gov (United States)

    SRD 4 NIST Thermophysical Properties of Hydrocarbon Mixtures (PC database for purchase)   Interactive computer program for predicting thermodynamic and transport properties of pure fluids and fluid mixtures containing up to 20 components. The components are selected from a database of 196 components, mostly hydrocarbons.

  19. Constrained Clar formulas of coronoid hydrocarbons.

    Science.gov (United States)

    Aihara, Jun-ichi; Makino, Masakazu

    2014-02-20

    Aromatic character of coronoid hydrocarbons is greatly influenced by the shapes of outer and inner peripheries. The most aromatic rings in coronoids are jutting benzene rings on the armchair edges, if any. Clar formulas of many coronoids conform to the aromaticity patterns. However, placement of all aromatic sextets on highly aromatic rings is sometimes forbidden by the presence of the central cavity. The magnitude of aromatic stabilization energy due to macrocyclic conjugation [SSE(mc)] and the NICS(1) value at the center of the cavity strongly depend on the structure of the superposed Clar formula. Localization of π-electrons in fixed aromatic sextets effectively suppresses macrocyclic conjugation. The sign of SSE(mc) is determined by the number of carbon atoms that form the hub cycle.

  20. Suppression in simultaneous masking.

    Science.gov (United States)

    Fastl, H; Bechly, M

    1983-09-01

    Suppression, i.e., the decrease of masked threshold caused by the addition of a second masker M2 to a first masker M1, is measured for the case of simultaneous masking. The magnitude of suppression decreases with increasing test tone duration; pulsed maskers elicit somewhat more suppression than continuous maskers. In comparison to suppression effects obtained in nonsimultaneous masking (post-masking, pulsation threshold) suppression in simultaneous masking is considerably smaller and was found only at the lower slopes of the two maskers. Suppression in simultaneous masking would not be predicted by those models of suppression which require nonsimultaneous presentation of maskers and test sound.

  1. Endocrine disrupting potentials of Bisphenol A, Bisphenol A dimethacrylate, 4-n-Nonyl-phenol and 4-Octylphenol assessed in cell model systems for effects on the estrogen-, androgen-, aryl hydrocarbon-receptor and aromatase activity

    DEFF Research Database (Denmark)

    Bonefeld-Jørgensen, Eva Cecilie; Long, Manhai; Hofmeister, Marlene V

      An array of plastic components is known to possess endocrine disruption (ED) potentials. Bisphenol A (BPA) and BPA-Dimethacrylate (BPA-DM) are monomers used to high extent in the plastic industry and as dental sealants. Alkylphenols such as 4-n-nonylphenol (NP) and 4-octylphenol (OP) are widely...... used as surfactants. We have investigated the effect in vitro of these four plasticizers in four cell culture model systems.The estrogenic potencies were analyzed using the stable ERE-luciferase transfected cell line MVLN measuring the relative estrogen receptor (ER) transactivated luciferase units...... (RLU). Effects on the Androgen receptor (AR) trans-activation were investigated by co-transfection of the CHO-K1 hamster cells using the reporter vector MMTV-LUC and the AR expression vector pSVAR0. Effects on the CYP19 aromatase, an important enzyme in the steroid synthesis pathway involved...

  2. Isoliquiritigenin Activates Nuclear Factor Erythroid-2 Related Factor 2 to Suppress the NOD-Like Receptor Protein 3 Inflammasome and Inhibits the NF-κB Pathway in Macrophages and in Acute Lung Injury

    Directory of Open Access Journals (