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Sample records for irs-2 pdx-1 glut-2

  1. Assessment of intravenous pbi-shRNA PDX1 nanoparticle (OFHIRNA-PDX1) in yucatan swine.

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    Jay, C M; Ruoff, C; Kumar, P; Maass, H; Spanhel, B; Miller, M; Arrington, A; Montalvo, N; Gresham, V; Rao, D D; Evans, C; Wang, Z; Brunicardi, F C; Liu, S-H; Zhou, G; Senzer, N; Nemunaitis, J; King, L; Weeks, B; Clubb, F J; Fossum, T W; Maples, P B

    2013-12-01

    PDX1 (pancreatic and duodenal homeobox 1) is overexpressed in pancreatic cancer, and its reduction results in tumor regression. Bi-functional pbi-shRNA PDX1 nanoparticle (OFHIRNA-PDX1) utilizes the endogenous micro-RNA biogenesis pathway to effect cleavage- and non-cleavage-dependent degradation of PDX1 mRNA. We have shown that OFHIRNA-PDX1 reduces pancreatic tumor volume in xenograft models. Thus, we are now exploring biorelevant large animal safety of OFHIRNA-PDX1. Mini pigs were chosen as the biorelevant species based on the similarity of human and pig PDX1 target sequence. In the initial study, animals developed fever, lethargy, hyporexia and cutaneous hyperemia following administration of OFHIRNA-PDX1. Twenty-one days later, the same animals demonstrated less toxicity with a second OFHIRNA-PDX1 infusion in conjunction with a prophylactic regimen involving dexamethasone, diphenhydramine, Indocin and ranitidine. In a new group of animals, PDX1 protein (31 kDa) expression in the pancreas was significantly repressed at 48 and 72 h (85%, P=0.018 and 88%, P=0.013; respectively) following a single infusion of OFHIRNA-PDX1 but recovered to normal state within 7 days. In conclusion, a single intravenous infusion of OFHIRNA-PDX1 in conjunction with premedication in pigs was well tolerated and demonstrated significant PDX1 knockdown.

  2. Cooperative function of Pdx1 and Oc1 in multipotent pancreatic progenitors impacts postnatal islet maturation and adaptability.

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    Kropp, Peter A; Dunn, Jennifer C; Carboneau, Bethany A; Stoffers, Doris A; Gannon, Maureen

    2018-04-01

    The transcription factors pancreatic and duodenal homeobox 1 (Pdx1) and onecut1 (Oc1) are coexpressed in multipotent pancreatic progenitors (MPCs), but their expression patterns diverge in hormone-expressing cells, with Oc1 expression being extinguished in the endocrine lineage and Pdx1 being maintained at high levels in β-cells. We previously demonstrated that cooperative function of these two factors in MPCs is necessary for proper specification and differentiation of pancreatic endocrine cells. In those studies, we observed a persistent decrease in expression of the β-cell maturity factor MafA. We therefore hypothesized that Pdx1 and Oc1 cooperativity in MPCs impacts postnatal β-cell maturation and function. Here our model of Pdx1-Oc1 double heterozygosity was used to investigate the impact of haploinsufficiency for both of these factors on postnatal β-cell maturation, function, and adaptability. Examining mice at postnatal day (P) 14, we observed alterations in pancreatic insulin content in both Pdx1 heterozygotes and double heterozygotes. Gene expression analysis at this age revealed significantly decreased expression of many genes important for glucose-stimulated insulin secretion (e.g., Glut2, Pcsk1/2, Abcc8) exclusively in double heterozygotes. Analysis of P14 islets revealed an increase in the number of mixed islets in double heterozygotes. We predicted that double-heterozygous β-cells would have an impaired ability to respond to stress. Indeed, we observed that β-cell proliferation fails to increase in double heterozygotes in response to either high-fat diet or placental lactogen. We thus report here the importance of cooperation between regulatory factors early in development for postnatal islet maturation and adaptability.

  3. An increase in immature β-cells lacking Glut2 precedes the expansion of β-cell mass in the pregnant mouse.

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    Christine A Beamish

    Full Text Available A compensatory increase in β-cell mass occurs during pregnancy to counter the associated insulin resistance, and a failure in adaptation is thought to contribute to gestational diabetes. Insulin-expressing but glucose-transporter-2-low (Ins+Glut2LO progenitor cells are present in mouse and human pancreas, being predominantly located in extra-islet β-cell clusters, and contribute to the regeneration of the endocrine pancreas following induced ablation. We therefore sought to investigate the contribution of Ins+Glut2LO cells to β-cell mass expansion during pregnancy. Female C57Bl/6 mice were time mated and pancreata were collected at gestational days (GD 6, 9, 12, 15, and 18, and postpartum D7 (n = 4/time-point and compared to control (non-pregnant animals. Beta cell mass, location, proliferation (Ki67+, and proportion of Ins+Glut2LO cells were measured using immunohistochemistry and bright field or confocal microscopy. Beta cell mass tripled by GD18 and β-cell proliferation peaked at GD12 in islets (≥6 β-cells and small β-cell clusters (1-5 β-cells. The proportion and fraction of Ins+Glut2LO cells undergoing proliferation increased significantly at GD9 in both islets and clusters, preceding the increase in β-cell mass and proliferation, and their proliferation within clusters persisted until GD15. The overall number of clusters increased significantly at GD9. Quantitative PCR showed a significant increase in Pdx1 presence at GD9 vs. GD18 or control pancreas, and Pdx1 was visualized by immunohistochemistry within both Ins+Glut2LO and Ins+Glut2HI cells within clusters. These results indicate that Ins+Glut2LO cells are likely to contribute to β-cell mass expansion during pregnancy.

  4. Genome-wide analysis of PDX1 target genes in human pancreatic progenitors

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    Xianming Wang

    2018-03-01

    Full Text Available Objective: Homozygous loss-of-function mutations in the gene coding for the homeobox transcription factor (TF PDX1 leads to pancreatic agenesis, whereas heterozygous mutations can cause Maturity-Onset Diabetes of the Young 4 (MODY4. Although the function of Pdx1 is well studied in pre-clinical models during insulin-producing β-cell development and homeostasis, it remains elusive how this TF controls human pancreas development by regulating a downstream transcriptional program. Also, comparative studies of PDX1 binding patterns in pancreatic progenitors and adult β-cells have not been conducted so far. Furthermore, many studies reported the association between single nucleotide polymorphisms (SNPs and T2DM, and it has been shown that islet enhancers are enriched in T2DM-associated SNPs. Whether regions, harboring T2DM-associated SNPs are PDX1 bound and active at the pancreatic progenitor stage has not been reported so far. Methods: In this study, we have generated a novel induced pluripotent stem cell (iPSC line that efficiently differentiates into human pancreatic progenitors (PPs. Furthermore, PDX1 and H3K27ac chromatin immunoprecipitation sequencing (ChIP-seq was used to identify PDX1 transcriptional targets and active enhancer and promoter regions. To address potential differences in the function of PDX1 during development and adulthood, we compared PDX1 binding profiles from PPs and adult islets. Moreover, combining ChIP-seq and GWAS meta-analysis data we identified T2DM-associated SNPs in PDX1 binding sites and active chromatin regions. Results: ChIP-seq for PDX1 revealed a total of 8088 PDX1-bound regions that map to 5664 genes in iPSC-derived PPs. The PDX1 target regions include important pancreatic TFs, such as PDX1 itself, RFX6, HNF1B, and MEIS1, which were activated during the differentiation process as revealed by the active chromatin mark H3K27ac and mRNA expression profiling, suggesting that auto-regulatory feedback regulation

  5. Foxa2 and Pdx1 cooperatively regulate postnatal maturation of pancreatic β-cells

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    Aimée Bastidas-Ponce

    2017-06-01

    Full Text Available Objective: The transcription factors (TF Foxa2 and Pdx1 are key regulators of beta-cell (β-cell development and function. Mutations of these TFs or their respective cis-regulatory consensus binding sites have been linked to maturity diabetes of the young (MODY, pancreas agenesis, or diabetes susceptibility in human. Although Foxa2 has been shown to directly regulate Pdx1 expression during mouse embryonic development, the impact of this gene regulatory interaction on postnatal β-cell maturation remains obscure. Methods: In order to easily monitor the expression domains of Foxa2 and Pdx1 and analyze their functional interconnection, we generated a novel double knock-in homozygous (FVFPBFDHom fluorescent reporter mouse model by crossing the previously described Foxa2-Venus fusion (FVF with the newly generated Pdx1-BFP (blue fluorescent protein fusion (PBF mice. Results: Although adult PBF homozygous animals exhibited a reduction in expression levels of Pdx1, they are normoglycemic. On the contrary, despite normal pancreas and endocrine development, the FVFPBFDHom reporter male animals developed hyperglycemia at weaning age and displayed a reduction in Pdx1 levels in islets, which coincided with alterations in β-cell number and islet architecture. The failure to establish mature β-cells resulted in loss of β-cell identity and trans-differentiation towards other endocrine cell fates. Further analysis suggested that Foxa2 and Pdx1 genetically and functionally cooperate to regulate maturation of adult β-cells. Conclusions: Our data show that the maturation of pancreatic β-cells requires the cooperative function of Foxa2 and Pdx1. Understanding the postnatal gene regulatory network of β-cell maturation will help to decipher pathomechanisms of diabetes and identify triggers to regenerate dedifferentiated β-cell mass. Keywords: Foxa2, Pdx1, β-Cell maturation, β-Cell identity, Trans-differentiation

  6. PDX-1 Is a Therapeutic Target for Pancreatic Cancer, Insulinoma and Islet Neoplasia Using a Novel RNA Interference Platform

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    Liu, Shi-He; Rao, Donald D.; Nemunaitis, John; Senzer, Neil; Zhou, Guisheng; Dawson, David; Gingras, Marie-Claude; Wang, Zhaohui; Gibbs, Richard; Norman, Michael; Templeton, Nancy S.; DeMayo, Francesco J.; O'Malley, Bert; Sanchez, Robbi; Fisher, William E.; Brunicardi, F. Charles

    2012-01-01

    Pancreatic and duodenal homeobox-1 (PDX-1) is a transcription factor that regulates insulin expression and islet maintenance in the adult pancreas. Our recent studies demonstrate that PDX-1 is an oncogene for pancreatic cancer and is overexpressed in pancreatic cancer. The purpose of this study was to demonstrate that PDX-1 is a therapeutic target for both hormonal symptoms and tumor volume in mouse models of pancreatic cancer, insulinoma and islet neoplasia. Immunohistochemistry of human pancreatic and islet neoplasia specimens revealed marked PDX-1 overexpression, suggesting PDX-1 as a “drugable” target within these diseases. To do so, a novel RNA interference effector platform, bifunctional shRNAPDX-1, was developed and studied in mouse and human cell lines as well as in mouse models of pancreatic cancer, insulinoma and islet neoplasia. Systemic delivery of bi-shRNAhumanPDX-1 lipoplexes resulted in marked reduction of tumor volume and improved survival in a human pancreatic cancer xenograft mouse model. bi-shRNAmousePDX-1 lipoplexes prevented death from hyperinsulinemia and hypoglycemia in an insulinoma mouse model. shRNAmousePDX-1 lipoplexes reversed hyperinsulinemia and hypoglycemia in an immune-competent mouse model of islet neoplasia. PDX-1 was overexpressed in pancreatic neuroendocrine tumors and nesidioblastosis. These data demonstrate that PDX-1 RNAi therapy controls hormonal symptoms and tumor volume in mouse models of pancreatic cancer, insulinoma and islet neoplasia, therefore, PDX-1 is a potential therapeutic target for these pancreatic diseases. PMID:22905092

  7. Requirement for Pdx1 in specification of latent endocrine progenitors in zebrafish

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    Ellertsdottir Elin

    2011-10-01

    Full Text Available Abstract Background Insulin-producing beta cells emerge during pancreas development in two sequential waves. Recently described later-forming beta cells in zebrafish show high similarity to second wave mammalian beta cells in developmental capacity. Loss-of-function studies in mouse and zebrafish demonstrated that the homeobox transcription factors Pdx1 and Hb9 are both critical for pancreas and beta cell development and discrete stage-specific requirements for these genes have been uncovered. Previously, exocrine and endocrine cell recovery was shown to follow loss of pdx1 in zebrafish, but the progenitor cells and molecular mechanisms responsible have not been clearly defined. In addition, interactions of pdx1 and hb9 in beta cell formation have not been addressed. Results To learn more about endocrine progenitor specification, we examined beta cell formation following morpholino-mediated depletion of pdx1 and hb9. We find that after early beta cell reduction, recovery occurs following loss of either pdx1 or hb9 function. Unexpectedly, simultaneous knockdown of both hb9 and pdx1 leads to virtually complete and persistent beta cell deficiency. We used a NeuroD:EGFP transgenic line to examine endocrine cell behavior in vivo and developed a novel live-imaging technique to document emergence and migration of late-forming endocrine precursors in real time. Our data show that Notch-responsive progenitors for late-arising endocrine cells are predominantly post mitotic and depend on pdx1. By contrast, early-arising endocrine cells are specified and differentiate independent of pdx1. Conclusions The nearly complete beta cell deficiency after combined loss of hb9 and pdx1 suggests functional cooperation, which we clarify as distinct roles in early and late endocrine cell formation. A novel imaging approach permitted visualization of the emergence of late endocrine cells within developing embryos for the first time. We demonstrate a pdx1-dependent

  8. Pancreatic differentiation of Pdx1-GFP reporter mouse induced pluripotent stem cells.

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    Porciuncula, Angelo; Kumar, Anujith; Rodriguez, Saray; Atari, Maher; Araña, Miriam; Martin, Franz; Soria, Bernat; Prosper, Felipe; Verfaillie, Catherine; Barajas, Miguel

    2016-12-01

    Efficient induction of defined lineages in pluripotent stem cells constitutes the determinant step for the generation of therapeutically relevant replacement cells to potentially treat a wide range of diseases, including diabetes. Pancreatic differentiation has remained an important challenge in large part because of the need to differentiate uncommitted pluripotent stem cells into highly specialized hormone-secreting cells, which has been shown to require a developmentally informed step-by-step induction procedure. Here, in the framework of using induced pluripotent stem cells (iPSCs) to generate pancreatic cells for pancreatic diseases, we have generated and characterized iPSCs from Pdx1-GFP transgenic mice. The use of a GFP reporter knocked into the endogenous Pdx1 promoter allowed us to monitor pancreatic induction based on the expression of Pdx1, a pancreatic master transcription factor, and to isolate a pure Pdx1-GFP + population for downstream applications. Differentiated cultures timely expressed markers specific to each stage and end-stage progenies acquired a rather immature beta-cell phenotype, characterized by polyhormonal expression even among cells highly expressing the Pdx1-GFP reporter. Our findings highlight the utility of employing a fluorescent protein reporter under the control of a master developmental gene in order to devise novel differentiation protocols for relevant cell types for degenerative diseases such as pancreatic beta cells for diabetes. Copyright © 2016 International Society of Differentiation. Published by Elsevier B.V. All rights reserved.

  9. PDX1, Neurogenin-3, and MAFA: critical transcription regulators for beta cell development and regeneration

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    Yaxi Zhu

    2017-11-01

    Full Text Available Abstract Transcription factors regulate gene expression through binding to specific enhancer sequences. Pancreas/duodenum homeobox protein 1 (PDX1, Neurogenin-3 (NEUROG3, and V-maf musculoaponeurotic fibrosarcoma oncogene homolog A (MAFA are transcription factors critical for beta cell development and maturation. NEUROG3 is expressed in endocrine progenitor cells and controls islet differentiation and regeneration. PDX1 is essential for the development of pancreatic exocrine and endocrine cells including beta cells. PDX1 also binds to the regulatory elements and increases insulin gene transcription. Likewise, MAFA binds to the enhancer/promoter region of the insulin gene and drives insulin expression in response to glucose. In addition to those natural roles in beta cell development and maturation, ectopic expression of PDX1, NEUROG3, and/or MAFA has been successfully used to reprogram various cell types into insulin-producing cells in vitro and in vivo, such as pancreatic exocrine cells, hepatocytes, and pluripotent stem cells. Here, we review biological properties of PDX1, NEUROG3, and MAFA, and their applications and limitations for beta cell regenerative approaches. The primary source literature for this review was acquired using a PubMed search for articles published between 1990 and 2017. Search terms include diabetes, insulin, trans-differentiation, stem cells, and regenerative medicine.

  10. Characterization of pancreatic transcription factor Pdx-1 binding sites using promoter microarray and serial analysis of chromatin occupancy

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    Keller, David M; McWeeney, Shannon; Arsenlis, Athanasios; Drouin, Jacques; Wright, Christopher V E; Wang, Haiyan; Wollheim, Claes; White, Peter; Kaestner, Klaus H; Goodman, Richard H

    2007-01-01

    The homeobox transcription factor Pdx-1 is necessary for pancreas organogenesis and beta cell function, however, most Pdx-1-regulated genes are unknown. To further the understanding of Pdx-1 in beta cell biology, we have characterized its genomic targets in NIT-1 cells, a mouse insulinoma cell line. To identify novel targets, we developed a microarray that includes traditional promoters as well as non-coding conserved elements, micro-RNAs, and elements identified through an unbiased approach ...

  11. Activin B mediated induction of Pdx1 in human embryonic stem cell derived embryoid bodies

    DEFF Research Database (Denmark)

    Frandsen, Ulrik; Pørneki, Ann Dorte Storm; Floridon, Charlotte

    2007-01-01

    embryonic and fetal pancreas anlage in humans. Pdx1(+) cells are found in cell clusters also expressing Serpina1 and FABP1, suggesting activation of intestinal/liver developmental programs. Moreover, Activin B up-regulates Sonic Hedgehog (Shh) and its target Gli1, which during normal development...

  12. Pdx1 is post-translationally modified in vivo and serine 61 is the principal site of phosphorylation

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    Frogne, Thomas; Sylvestersen, Kathrine Beck; Kubicek, Stefan

    2012-01-01

    signaling. Several studies have shown that post-translational modifications are regulating Pdx1 activity through intracellular localization and binding to co-factors. Understanding the signaling cues converging on Pdx1 and modulating its activity is therefore an attractive approach in diabetes treatment. We...... alanine scanning and mass spectrometry we map this phosphorylation to serine 61 in both Min6 cells and in exogenous Pdx1 over-expressed in HEK293 cells. A single phosphorylation is also present in cultured islets but it remains unaffected by changes in glucose levels. It is present during embryogenesis...

  13. Differentiation of Human Mesenchymal Stem Cells into Insulin Producing Cells by Using A Lentiviral Vector Carrying PDX1.

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    Allahverdi, Amir; Abroun, Saied; Jafarian, Arefeh; Soleimani, Masoud; Taghikhani, Mohammad; Eskandari, Fatemeh

    2015-01-01

    Type I diabetes is an immunologically-mediated devastation of insulin producing cells (IPCs) in the pancreatic islet. Stem cells that produce β-cells are a new promising tool. Adult stem cells such as mesenchymal stem cells (MSCs) are self renewing multi potent cells showing capabilities to differentiate into ectodermal, mesodermal and endodermal tissues. Pancreatic and duodenal homeobox factor 1 (PDX1) is a master regulator gene required for embryonic development of the pancreas and is crucial for normal pancreatic islets activities in adults. We induced the over-expression of the PDX1 gene in human bone marrow MSCs (BM-MSCs) by Lenti-PDX1 in order to generate IPCs. Next, we examine the ability of the cells by measuring insulin/c-peptide production and INSULIN and PDX1 gene expressions. After transduction, MSCs changed their morphology at day 5 and gradually differentiated into IPCs. INSULIN and PDX1 expressions were confirmed by real time polymerase chain reaction (RT-PCR) and immunostaining. IPC secreted insulin and C-peptide in the media that contained different glucose concentrations. MSCs differentiated into IPCs by genetic manipulation. Our result showed that lentiviral vectors could deliver PDX1 gene to MSCs and induce pancreatic differentiation.

  14. GLUT2-mediated glucose uptake and availability are required for embryonic brain development in zebrafish.

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    Marín-Juez, Rubén; Rovira, Mireia; Crespo, Diego; van der Vaart, Michiel; Spaink, Herman P; Planas, Josep V

    2015-01-01

    Glucose transporter 2 (GLUT2; gene name SLC2A2) has a key role in the regulation of glucose dynamics in organs central to metabolism. Although GLUT2 has been studied in the context of its participation in peripheral and central glucose sensing, its role in the brain is not well understood. To decipher the role of GLUT2 in brain development, we knocked down slc2a2 (glut2), the functional ortholog of human GLUT2, in zebrafish. Abrogation of glut2 led to defective brain organogenesis, reduced glucose uptake and increased programmed cell death in the brain. Coinciding with the observed localization of glut2 expression in the zebrafish hindbrain, glut2 deficiency affected the development of neural progenitor cells expressing the proneural genes atoh1b and ptf1a but not those expressing neurod. Specificity of the morphant phenotype was demonstrated by the restoration of brain organogenesis, whole-embryo glucose uptake, brain apoptosis, and expression of proneural markers in rescue experiments. These results indicate that glut2 has an essential role during brain development by facilitating the uptake and availability of glucose and support the involvement of glut2 in brain glucose sensing.

  15. Dynamic Recruitment of Functionally Distinct Swi/Snf Chromatin Remodeling Complexes Modulates Pdx1 Activity in Islet β Cells

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    Brian McKenna

    2015-03-01

    Full Text Available Pdx1 is a transcription factor of fundamental importance to pancreas formation and adult islet β cell function. However, little is known about the positive- and negative-acting coregulators recruited to mediate transcriptional control. Here, we isolated numerous Pdx1-interacting factors possessing a wide range of cellular functions linked with this protein, including, but not limited to, coregulators associated with transcriptional activation and repression, DNA damage response, and DNA replication. Because chromatin remodeling activities are essential to developmental lineage decisions and adult cell function, our analysis focused on investigating the influence of the Swi/Snf chromatin remodeler on Pdx1 action. The two mutually exclusive and indispensable Swi/Snf core ATPase subunits, Brg1 and Brm, distinctly affected target gene expression in β cells. Furthermore, physiological and pathophysiological conditions dynamically regulated Pdx1 binding to these Swi/Snf complexes in vivo. We discuss how context-dependent recruitment of coregulatory complexes by Pdx1 could impact pancreas cell development and adult islet β cell activity.

  16. NKX2.2, PDX-1 and CDX-2 as potential biomarkers to differentiate well-differentiated neuroendocrine tumors.

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    Yang, Michelle X; Coates, Ryan F; Ambaye, Abiy; Cortright, Valerie; Mitchell, Jeannette M; Buskey, Alexa M; Zubarik, Richard; Liu, James G; Ades, Steven; Barry, Maura M

    2018-01-01

    Well-differentiated neuroendocrine tumors (NET) most frequently arise from the gastrointestinal tract (GI), pancreas, and lung. Patients often present as metastasis with an unknown primary, and the clinical management and outcome depend on multiple factors, including the accurate diagnosis with the tumor primary site. Determining the site of the NET with unknown primary remains challenging. Many biomarkers have been investigated in primary NETs and metastatic NETs, with heterogeneous sensitivity and specificity observed. We used high-throughput tissue microarray (TMA) and immunohistochemistry (IHC) with antibodies against a panel of transcriptional factors including NKX2.2, PDX-1, PTF1A, and CDX-2 on archived formalin-fixed paraffin-embedded NETs, and investigated the protein expression pattern of these transcription factors in 109 primary GI ( N  = 81), pancreatic ( N  = 17), and lung ( N  = 11) NETs. Differential expression pattern of these markers was observed. In the GI and pancreatic NETs ( N  = 98), NKX2.2, PDX-1, and CDX-2 were immunoreactive in 82 (84%), 14 (14%), and 52 (52%) cases, respectively. PDX-1 was expressed mainly in the small intestinal and appendiceal NETs, occasionally in the pancreatic NETs, and not in the colorectal NETs. All three biomarkers including NKX2.2, PDX-1, and CDX-2 were completely negative in lung NETs. PTF1A was expressed in all normal and neuroendocrine tumor cells. Our findings suggest that NKX2.2 was a sensitive and specific biomarker for the GI and pancreatic neuroendocrine tumors. We proposed that a panel of immunostains including NKX2.2, PDX-1, and CDX-2 may show diagnostic utility for the most common NETs.

  17. Pdx1 and Ngn3 overexpression enhances pancreatic differentiation of mouse ES cell-derived endoderm population.

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    Kubo, Atsushi; Stull, Robert; Takeuchi, Mitsuaki; Bonham, Kristina; Gouon-Evans, Valerie; Sho, Masayuki; Iwano, Masayuki; Saito, Yoshihiko; Keller, Gordon; Snodgrass, Ralph

    2011-01-01

    In order to define the molecular mechanisms regulating the specification and differentiation of pancreatic β-islet cells, we investigated the effect of upregulating Pdx1 and Ngn3 during the differentiation of the β-islet-like cells from murine embryonic stem (ES) cell-derived activin induced-endoderm. Induced overexpression of Pdx1 resulted in a significant upregulation of insulin (Ins1 and Ins2), and other pancreas-related genes. To enhance the developmental progression from the pancreatic bud to the formation of the endocrine lineages, we induced the overexpression express of Ngn3 together with Pdx1. This combination dramatically increased the level and timing of maximal Ins1 mRNA expression to approximately 100% of that found in the βTC6 insulinoma cell line. Insulin protein and C-peptide expression was confirmed by immunohistochemistry staining. These inductive effects were restricted to c-kit(+) endoderm enriched EB-derived populations suggesting that Pdx1/Ngn3 functions after the specification of pancreatic endoderm. Although insulin secretion was stimulated by various insulin secretagogues, these cells had only limited glucose response. Microarray analysis was used to evaluate the expression of a broad spectrum of pancreatic endocrine cell-related genes as well as genes associated with glucose responses. Taken together, these findings demonstrate the utility of manipulating Pdx1 and Ngn3 expression in a stage-specific manner as an important new strategy for the efficient generation of functionally immature insulin-producing β-islet cells from ES cells.

  18. Pdx1 and Ngn3 overexpression enhances pancreatic differentiation of mouse ES cell-derived endoderm population.

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    Atsushi Kubo

    Full Text Available In order to define the molecular mechanisms regulating the specification and differentiation of pancreatic β-islet cells, we investigated the effect of upregulating Pdx1 and Ngn3 during the differentiation of the β-islet-like cells from murine embryonic stem (ES cell-derived activin induced-endoderm. Induced overexpression of Pdx1 resulted in a significant upregulation of insulin (Ins1 and Ins2, and other pancreas-related genes. To enhance the developmental progression from the pancreatic bud to the formation of the endocrine lineages, we induced the overexpression express of Ngn3 together with Pdx1. This combination dramatically increased the level and timing of maximal Ins1 mRNA expression to approximately 100% of that found in the βTC6 insulinoma cell line. Insulin protein and C-peptide expression was confirmed by immunohistochemistry staining. These inductive effects were restricted to c-kit(+ endoderm enriched EB-derived populations suggesting that Pdx1/Ngn3 functions after the specification of pancreatic endoderm. Although insulin secretion was stimulated by various insulin secretagogues, these cells had only limited glucose response. Microarray analysis was used to evaluate the expression of a broad spectrum of pancreatic endocrine cell-related genes as well as genes associated with glucose responses. Taken together, these findings demonstrate the utility of manipulating Pdx1 and Ngn3 expression in a stage-specific manner as an important new strategy for the efficient generation of functionally immature insulin-producing β-islet cells from ES cells.

  19. Small molecule kaempferol modulates PDX-1 protein expression and subsequently promotes pancreatic β-cell survival and function via CREB

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    Zhang, Yanling.; Zhen, Wei.; Maechler, Pierre; Liu, Dongmin

    2013-01-01

    Chronic hyperlipidemia causes β-cell apoptosis and dysfunction, thereby contributing to the pathogenesis of T2D. Thus, searching for agents to promote pancreatic β-cell survival and improve its function could be a promising strategy to prevent and treat T2D. We investigated the effects of kaempferol, a small molecule isolated from ginkgo biloba, on apoptosis and function of β-cells and further determined the mechanism underlying its actions. Kaempferol treatment promoted viability, inhibited apoptosis, and reduced caspase-3 activity in INS-1E cells and human islets chronically exposed to palmitate. In addition, kaempferol prevented the lipotoxicity-induced down-regulation of anti-apoptotic proteins Akt and Bcl-2. The cytoprotective effects of kaempferol were associated with improved insulin secretion, synthesis, and PDX-1 expression. Chronic hyperlipidemia significantly diminished cAMP production, PKA activation, and CREB phosphorylation and its regulated transcriptional activity in β-cells, all of which were restored by kaempferol treatment. Disruption of CREB expression by transfection of CREB siRNA in INS-1E cells or adenoviral transfer of dominant-negative forms of CREB in human islets ablated kaempferol protection of β-cell apoptosis and dysfunction caused by palmitate. Incubation of INS-1E cells or human islets with kaempferol for 48 h induced PDX-1 expression. This effect of kaempferol on PDX-1 expression was not shared by a host of structurally related flavonoid compounds. PDX-1 gene knockdown reduced kaempferol–stimulated cAMP generation and CREB activation in INS-1E cells. These findings demonstrate that kaempferol is a novel survivor factor for pancreatic β-cells via up-regulating the PDX-1/cAMP/PKA/CREB signaling cascade. PMID:22819546

  20. GLUT2 and the incretin receptors are involved in glucose-induced incretin secretion

    DEFF Research Database (Denmark)

    Cani, Patrice D; Holst, Jens Juul; Drucker, Daniel J

    2007-01-01

    to those described for beta-cells, brain and hepatoportal sensors. We determined the role of GLUT2, GLP-1 or GIP receptors in glucose-induced incretins secretion, in the corresponding knockout mice. GLP-1 secretion was reduced in all mutant mice, while GIP secretion did not require GLUT2. Intestinal GLP-1...... content was reduced only in GIP and GLUT2 receptors knockout mice suggesting that this impairment could contribute to the phenotype. Intestinal GIP content was similar in all mice studied. Furthermore, the impaired incretins secretion was associated with a reduced glucose-stimulated insulin secretion...

  1. Construction Of An Optimized Lentiviral Vector Containing Pdx-1 Gene For Transduction Of Stem Cells Towards Gene Therapy Diabetes Type 1

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    S Rahmati

    2013-02-01

    Full Text Available Abstract Background & aim: Nowadays, most of gene therapy protocols are performed by lentiviral vectors. One of the most important factors which is involved in pancreas development and transcription of insulin gene is pancreatic & duodenal homeobox 1 (PDX-1 transcription factor. The goal of this study was to optimize a lentiviral construct, containing pdx-1 gene, to transfect stem cells towards gene therapy of type-1 diabetes. Methods: In this experimental study, first, the pdx-1 gene was multiplied by PCR from pcDNA3.1-pdx-1 and cloned into pTG19-T vector. Then, pdx-1 was subcloned on upstream of IRES-EGFP gene into IRES2-EGFP vector. At the next step, the cloned parts of IRES-EGFP and pdx-1 were isolated and cloned into the lentiviral expression vector pSINTREM in upstream of TRE-CMV gene. After sequencing, final construct was transfected into HEK 293 cells and gene expression of pdx-1 was evaluated using flow cytometry analysis and reverse fluorescent microscopy. Results: Flow cytometry results and inverted fluorescent microscopy observing showed that pdx-1 and GFP genes are expressed in cells transfected with final recombinant construct. Conclusion: Regarding the design of this construct, to ensure long time expression with higher in vivo and in vitro expression efficiency for stem cells and also use of Tet on induced optimized system, it seems that the current construct can be among the best ones to transfect stem cells. Key words: Gene therapy, Diabetes, Stem cells

  2. Differentiation of PDX1 gene-modified human umbilical cord mesenchymal stem cells into insulin-producing cells in vitro.

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    He, Dongmei; Wang, Juan; Gao, Yangjun; Zhang, Yuan

    2011-12-01

    Mesenchymal stem cells (MSCs) have significant advantages over other stem cell types, and greater potential for immediate clinical application. MSCs would be an interesting cellular source for treatment of type 1 diabetes. In this study, MSCs from human umbilical cord were differentiated into functional insulin-producing cells in vitro by introduction of the pancreatic and duodenal homeobox factor 1 (PDX1) and in the presence of induction factors. The expressions of cell surface antigens were detected by flow cytometry. After induction in an adipogenic medium or an osteogenic medium, the cells were observed by Oil Red O staining and alkaline phosphatase staining. Recombinant adenovirus carrying the PDX1 gene was constructed and MSCs were infected by the recombinant adenovirus, then treated with several inducing factors for differentiation into islet β-like cells. The expression of the genes and protein related to islet β-cells was detected by immunocytochemistry, RT-PCR and Western blot analysis. Insulin and C-peptide secretion were assayed. Our results show that the morphology and immunophenotype of MSCs from human umbilical cord were similar to those present in human bone marrow. The MSCs could be induced to differentiate into osteocytes and adipocytes. After induction by recombined adenovirus vector with induction factors, MSCs were aggregated and presented islet-like bodies. Dithizone staining of these cells was positive. The genes' expression related to islet β-cells was found. After induction, insulin and C-peptide secretion in the supernatant were significantly increased. In conclusion, our results demonstrated that PDX1 gene-modified human umbilical cord mesenchymal stem cells could be differentiated into insulin-producing cells in vitro.

  3. Improved differentiation of umbilical cord blood-derived mesenchymal stem cells into insulin-producing cells by PDX-1 mRNA transfection.

    Science.gov (United States)

    Van Pham, Phuc; Thi-My Nguyen, Phuoc; Thai-Quynh Nguyen, Anh; Minh Pham, Vuong; Nguyen-Tu Bui, Anh; Thi-Tung Dang, Loan; Gia Nguyen, Khue; Kim Phan, Ngoc

    2014-06-01

    Numerous studies have sought to identify diabetes mellitus treatment strategies with fewer side effects. Mesenchymal stem cell (MSC) therapy was previously considered as a promising therapy; however, it requires the cells to be trans-differentiated into cells of the pancreatic-endocrine lineage before transplantation. Previous studies have shown that PDX-1 expression can facilitate MSC differentiation into insulin-producing cells (IPCs), but the methods employed to date use viral or DNA-based tools to express PDX-1, with the associated risks of insertional mutation and immunogenicity. Thus, this study aimed to establish a new method to induce PDX-1 expression in MSCs by mRNA transfection. MSCs were isolated from human umbilical cord blood and expanded in vitro, with stemness confirmed by surface markers and multipotentiality. MSCs were transfected with PDX-1 mRNA by nucleofection and chemically induced to differentiate into IPCs (combinatorial group). This IPC differentiation was then compared with that of untransfected chemically induced cells (inducer group) and uninduced cells (control group). We found that PDX-1 mRNA transfection significantly improved the differentiation of MSCs into IPCs, with 8.3±2.5% IPCs in the combinatorial group, 3.21±2.11% in the inducer group and 0% in the control. Cells in the combinatorial group also strongly expressed several genes related to beta cells (Pdx-1, Ngn3, Nkx6.1 and insulin) and could produce C-peptide in the cytoplasm and insulin in the supernatant, which was dependent on the extracellular glucose concentration. These results indicate that PDX-1 mRNA may offer a promising approach to produce safe IPCs for clinical diabetes mellitus treatment. Copyright © 2014 International Society of Differentiation. Published by Elsevier B.V. All rights reserved.

  4. Identification of epidermal Pdx1 expression discloses different roles of Notch1 and Notch2 in murine Kras(G12D-induced skin carcinogenesis in vivo.

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    Pawel K Mazur

    Full Text Available BACKGROUND: The Ras and Notch signaling pathways are frequently activated during development to control many diverse cellular processes and are often dysregulated during tumorigenesis. To study the role of Notch and oncogenic Kras signaling in a progenitor cell population, Pdx1-Cre mice were utilized to generate conditional oncogenic Kras(G12D mice with ablation of Notch1 and/or Notch2. METHODOLOGY/PRINCIPAL FINDINGS: Surprisingly, mice with activated Kras(G12D and Notch1 but not Notch2 ablation developed skin papillomas progressing to squamous cell carcinoma providing evidence for Pdx1 expression in the skin. Immunostaining and lineage tracing experiments indicate that PDX1 is present predominantly in the suprabasal layers of the epidermis and rarely in the basal layer. Further analysis of keratinocytes in vitro revealed differentiation-dependent expression of PDX1 in terminally differentiated keratinocytes. PDX1 expression was also increased during wound healing. Further analysis revealed that loss of Notch1 but not Notch2 is critical for skin tumor development. Reasons for this include distinct Notch expression with Notch1 in all layers and Notch2 in the suprabasal layer as well as distinctive p21 and β-catenin signaling inhibition capabilities. CONCLUSIONS/SIGNIFICANCE: Our results provide strong evidence for epidermal expression of Pdx1 as of yet not identified function. In addition, this finding may be relevant for research using Pdx1-Cre transgenic strains. Additionally, our study confirms distinctive expression and functions of Notch1 and Notch2 in the skin supporting the importance of careful dissection of the contribution of individual Notch receptors.

  5. Loss of sugar detection by GLUT2 affects glucose homeostasis in mice.

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    Emilie Stolarczyk

    Full Text Available BACKGROUND: Mammals must sense the amount of sugar available to them and respond appropriately. For many years attention has focused on intracellular glucose sensing derived from glucose metabolism. Here, we studied the detection of extracellular glucose concentrations in vivo by invalidating the transduction pathway downstream from the transporter-detector GLUT2 and measured the physiological impact of this pathway. METHODOLOGY/PRINCIPAL FINDINGS: We produced mice that ubiquitously express the largest cytoplasmic loop of GLUT2, blocking glucose-mediated gene expression in vitro without affecting glucose metabolism. Impairment of GLUT2-mediated sugar detection transiently protected transgenic mice against starvation and streptozotocin-induced diabetes, suggesting that both low- and high-glucose concentrations were not detected. Transgenic mice favored lipid oxidation, and oral glucose was slowly cleared from blood due to low insulin production, despite massive urinary glucose excretion. Kidney adaptation was characterized by a lower rate of glucose reabsorption, whereas pancreatic adaptation was associated with a larger number of small islets. CONCLUSIONS/SIGNIFICANCE: Molecular invalidation of sugar sensing in GLUT2-loop transgenic mice changed multiple aspects of glucose homeostasis, highlighting by a top-down approach, the role of membrane glucose receptors as potential therapeutic targets.

  6. Reprogramming of various cell types to a beta-like state by Pdx1, Ngn3 and MafA.

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    Ersin Akinci

    Full Text Available The three transcription factors, PDX1, NGN3 and MAFA, are very important in pancreatic development. Overexpression of these three factors can reprogram both pancreatic exocrine cells and SOX9-positive cells of the liver into cells resembling pancreatic beta cells. In this study we investigate whether other cell types can be reprogrammed. Eight cell types are compared and the results are consistent with the idea that reprogramming occurs to a greater degree for developmentally related cells (pancreas, liver than for other types, such as fibroblasts. Using a line of mouse hepatocyte-derived cells we screened 13 compounds for the ability to increase the yield of reprogrammed cells. Three are active and when used in combination they can increase the yield of insulin-immunopositive cells by a factor of six. These results should contribute to the eventual ability to develop a new cure for diabetes based on the ability to reprogram other cells in the body to a beta cell phenotype.

  7. Glut2-dependent glucose-sensing controls thermoregulation by enhancing the leptin sensitivity of NPY and POMC neurons.

    Science.gov (United States)

    Mounien, Lourdes; Marty, Nell; Tarussio, David; Metref, Salima; Genoux, David; Preitner, Frédéric; Foretz, Marc; Thorens, Bernard

    2010-06-01

    The physiological contribution of glucose in thermoregulation is not completely established nor whether this control may involve a regulation of the melanocortin pathway. Here, we assessed thermoregulation and leptin sensitivity of hypothalamic arcuate neurons in mice with inactivation of glucose transporter type 2 (Glut2)-dependent glucose sensing. Mice with inactivation of Glut2-dependent glucose sensors are cold intolerant and show increased susceptibility to food deprivation-induced torpor and abnormal hypothermic response to intracerebroventricular administration of 2-deoxy-d-glucose compared to control mice. This is associated with a defect in regulated expression of brown adipose tissue uncoupling protein I and iodothyronine deiodinase II and with a decreased leptin sensitivity of neuropeptide Y (NPY) and proopiomelanocortin (POMC) neurons, as observed during the unfed-to-refed transition or following i.p. leptin injection. Sites of central Glut-2 expression were identified by a genetic tagging approach and revealed that glucose-sensitive neurons were present in the lateral hypothalamus, the dorsal vagal complex, and the basal medulla but not in the arcuate nucleus. NPY and POMC neurons were, however, connected to nerve terminals from Glut2-expressing neurons. Thus, our data suggest that glucose controls thermoregulation and the leptin sensitivity of NPY and POMC neurons through activation of Glut2-dependent glucose-sensing neurons located outside of the arcuate nucleus.

  8. GLUT2 in pancreatic islets: crucial target molecule in diabetes induced with multiple low doses of streptozotocin in mice.

    Science.gov (United States)

    Wang, Z; Gleichmann, H

    1998-01-01

    In mice, diabetes can be induced by multiple low doses of streptozotocin (MLD-STZ), i.e., 40 mg/kg body wt on each of 5 consecutive days. In this model, diabetes develops only when STZ induces both beta-cell toxicity and T-cell-dependent immune reactions. The target molecule(s) of MLD-STZ-induced beta-cell toxicity are not known, however. In this study, we report that GLUT2 is a target molecule for MLD-STZ toxicity. Ex vivo, a gradual decrement of both GLUT2 protein and mRNA expression was found in pancreatic islets isolated from MLD-STZ-treated C57BL/6 male mice, whereas mRNA expression of beta-actin, glucokinase, and proinsulin remained unaffected. Significant reduction of both GLUT2 protein and mRNA expression was first noted 1 day after the third STZ injection, clearly preceding the onset of hyperglycemia. The extent of reduction increased with the number of STZ injections administered and increased over time, after the last, i.e., fifth, STZ injection. The STZ-induced reduction of GLUT2 protein and mRNA was not due to an essential loss of beta-cells, because ex vivo, not only the total RNA yield and protein content in isolated islets, but also proinsulin mRNA expression, failed to differ significantly in the differently treated groups. Furthermore, islets isolated from MLD-STZ-treated donors responded to the nonglucose secretagogue arginine in a pattern similar to that of solvent-treated donors. Interestingly, the MLD-STZ-induced reduction of both GLUT2 protein and mRNA was prevented by preinjecting mice with 5-thio-D-glucose before each STZ injection. Apparently, GLUT2 is a crucial target molecule of MLD-STZ toxicity, and this toxicity seems to precede the immune reactions against beta-cells.

  9. Ebselen treatment prevents islet apoptosis, maintains intranuclear Pdx-1 and MafA levels, and preserves β-cell mass and function in ZDF rats.

    Science.gov (United States)

    Mahadevan, Jana; Parazzoli, Susan; Oseid, Elizabeth; Hertzel, Ann V; Bernlohr, David A; Vallerie, Sara N; Liu, Chang-qin; Lopez, Melissa; Harmon, Jamie S; Robertson, R Paul

    2013-10-01

    We reported earlier that β-cell-specific overexpression of glutathione peroxidase (GPx)-1 significantly ameliorated hyperglycemia in diabetic db/db mice and prevented glucotoxicity-induced deterioration of β-cell mass and function. We have now ascertained whether early treatment of Zucker diabetic fatty (ZDF) rats with ebselen, an oral GPx mimetic, will prevent β-cell deterioration. No other antihyperglycemic treatment was given. Ebselen ameliorated fasting hyperglycemia, sustained nonfasting insulin levels, lowered nonfasting glucose levels, and lowered HbA1c levels with no effects on body weight. Ebselen doubled β-cell mass, prevented apoptosis, prevented expression of oxidative stress markers, and enhanced intranuclear localization of pancreatic and duodenal homeobox (Pdx)-1 and v-maf musculoaponeurotic fibrosarcoma oncogene family, protein A (MafA), two critical insulin transcription factors. Minimal β-cell replication was observed in both groups. These findings indicate that prevention of oxidative stress is the mechanism whereby ebselen prevents apoptosis and preserves intranuclear Pdx-1 and MafA, which, in turn, is a likely explanation for the beneficial effects of ebselen on β-cell mass and function. Since ebselen is an oral antioxidant currently used in clinical trials, it is a novel therapeutic candidate to ameliorate fasting hyperglycemia and further deterioration of β-cell mass and function in humans undergoing the onset of type 2 diabetes.

  10. Diabetes-Resistant NOR Mice Are More Severely Affected by Streptozotocin Compared to the Diabetes-Prone NOD Mice: Correlations with Liver and Kidney GLUT2 Expressions

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    S. Kahraman

    2015-01-01

    Full Text Available Nonobese Diabetic (NOD mice are susceptible strains for Type 1 diabetes development, and Nonobese Diabetes-Resistant (NOR mice are defined as suitable controls for NOD mice in non-MHC-related research. Diabetes is often accelerated in NOD mice via Streptozotocin (STZ. STZ is taken inside cells via GLUT2 transmembrane carrier proteins, the major glucose transporter isoforms in pancreatic beta cells, liver, kidneys, and the small intestine. We observed severe adverse effects in NOR mice treated with STZ compared to NOD mice that were made diabetic with a similar dose. We suggested that the underlying mechanism could be differential GLUT2 expressions in pancreatic beta cells, yet immunofluorescent and immunohistochemical studies revealed similar GLUT2 expression levels. We also detected GLUT2 expression profiles in NOD and NOR hepatic and renal tissues by western blot analysis and observed considerably higher GLUT2 expression levels in liver and kidney tissues of NOR mice. Although beta cell GLUT2 expression levels are frequently evaluated as a marker predicting STZ sensitivity in animal models, we report here very different diabetic responses to STZ in two different animal strains, in spite of similar initial GLUT2 expressions in beta cells. Furthermore, use of NOR mice in STZ-mediated experimental diabetes settings should be considered accordingly.

  11. Rosiglitazone stimulates the release and synthesis of insulin by enhancing GLUT-2, glucokinase and BETA2/NeuroD expression

    International Nuclear Information System (INIS)

    Kim, Hyo-Sup; Noh, Jung-Hyun; Hong, Seung-Hyun; Hwang, You-Cheol; Yang, Tae-Young; Lee, Myung-Shik; Kim, Kwang-Won; Lee, Moon-Kyu

    2008-01-01

    Peroxisome proliferator-activated receptor (PPAR)-γ is a member of the nuclear receptor superfamily, and its ligands, the thiazolidinediones, might directly stimulate insulin release and insulin synthesis in pancreatic β-cells. In the present study, we examined the effects of rosiglitazone (RGZ) on insulin release and synthesis in pancreatic β-cell (INS-1). Insulin release and synthesis were stimulated by treatment with RGZ for 24 h. RGZ upregulated the expressions of GLUT-2 and glucokinase (GCK). Moreover, it was found that RGZ increased the expression of BETA2/NeuroD gene which could regulate insulin gene expression. These results suggest that RGZ could stimulate the release and synthesis of insulin through the upregulation of GLUT-2, GCK, and BETA2/NeuroD gene expression

  12. The ergogenic supplement β-hydroxy-β-methylbutyrate (HMB) attenuates insulin resistance through suppressing GLUT-2 in rat liver.

    Science.gov (United States)

    Sharawy, Maha H; El-Awady, Mohammed S; Megahed, Nirmeen; Gameil, Nariman M

    2016-05-01

    This study investigates the effect of the ergogenic supplement β-hydroxy-β-methylbutyrate (HMB) on insulin resistance induced by high-fructose diet (HFD) in rats. Male Sprague Dawley rats were fed 60% HFD for 12 weeks and HMB (320 mg·kg(-1)·day(-1), orally) for 4 weeks. HFD significantly increased fasting insulin, fasting glucose, glycosylated hemoglobin (HBA1C), liver glycogen content, and homeostasis model assessment of insulin resistance (HOMA-IR) index, while it decreased glucose and insulin tolerance. Furthermore, HFD significantly increased serum triglycerides (TG), low density lipoprotein cholesterol (LDL-C), and very low density lipoprotein cholesterol (VLDL-C) levels, while it significantly decreased high density lipoprotein cholesterol (HDL-C). Moreover, HFD significantly increased mRNA expression of glucose transporter type-2 (GLUT-2), the mammalian target of rapamycin (mTOR), and sterol regulatory element-binding protein-1c (SREBP-1c) but decreased peroxisome proliferator-activated receptor-alpha (PPAR-α) in liver. Aortic relaxation to acetylcholine (ACh) was impaired and histopathology showed severe hepatic steatosis. HMB significantly increased insulin tolerance and decreased fasting insulin, HOMA-IR, HBA1C, hepatic glycogen content, serum TG, LDL-C, and VLDL-C. Additionally, HMB enhanced ACh-induced relaxation, ameliorated hepatic steatosis, and decreased mRNA expression of GLUT-2. In conclusion, HMB may attenuate insulin resistance and hepatic steatosis through inhibiting GLUT-2 in liver.

  13. Changes on the Pancreas in Experimental Diabetes and the Effect of Lycopene on These Changes: Pdx-1, Ngn-3, and Nestin Expressions.

    Science.gov (United States)

    Sandikci, Mustafa; Karagenc, Levent; Yildiz, Mustafa

    2017-12-01

    The aim of the present study was to investigate changes occurring in the number of beta cells, as well as the expressions of Ngn-3, nestin and Pdx-1 of pancreatic progenitor cells in the pancreas of experimentally-induced adult diabetic rats and to determine the effect of orally-administered lycopene on these changes. Following the administration of 50 mg/kg streptozotocin to rats, four groups of animals were established: control + corn oil, control + lycopene, diabetic + corn oil and diabetic + lycopene. The animals in the control + lycopene and diabetic + lycopene groups received 4 mg/kg lycopene for a period of four weeks. The expressions of insulin, Ngn-3, nestin, and Pdx-1 were determined through immunohistochemistry in sections taken from pancreas tissue samples at the end of the experiment. The number of insulin-positive cells was found to be significantly low in the diabetic groups compared to the control groups. In addition, the presence of Ngn-3 and nestin-positive cells within the exocrine pancreas surrounding the islands was noted in the diabetic groups. Lycopene, in general did not have any effect in any of the parameters analyzed in the present study. It is suggested that these cells would function as stem cells to replace the lost beta-cell population. It is also suggested that it is possible to demonstrate the antioxidant effects of lycopene in the pancreas of diabetic rats by increasing the dose and duration of lycopene administration. Anat Rec, 300:2200-2207, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  14. (19)F-heptuloses as tools for the non-invasive imaging of GLUT2-expressing cells

    DEFF Research Database (Denmark)

    Malaisse, Willy J; Zhang, Ying; Louchami, Karim

    2012-01-01

    Suitable analogs of d-mannoheptulose are currently considered as possible tools for the non-invasive imaging of pancreatic islet insulin-producing cells. Here, we examined whether (19)F-heptuloses could be used for non-invasive imaging of GLUT2-expressing cells. After 20 min incubation, the uptake......-mannoheptulose in inhibiting insulin release. The 1-deoxy-1-fluoro-d-mannoheptulose and 3-deoxy-3-fluoro-d-mannoheptulose only marginally affected INS-1 cell viability. These findings are compatible with the view that selected (19)F-heptuloses may represent suitable tools for the non-invasive imaging of hepatocytes...

  15. The Cdk4-E2f1 pathway regulates early pancreas development by targeting Pdx1+ progenitors and Ngn3+ endocrine precursors

    Science.gov (United States)

    Kim, So Yoon; Rane, Sushil G.

    2011-01-01

    Cell division and cell differentiation are intricately regulated processes vital to organ development. Cyclin-dependent kinases (Cdks) are master regulators of the cell cycle that orchestrate the cell division and differentiation programs. Cdk1 is essential to drive cell division and is required for the first embryonic divisions, whereas Cdks 2, 4 and 6 are dispensable for organogenesis but vital for tissue-specific cell development. Here, we illustrate an important role for Cdk4 in regulating early pancreas development. Pancreatic development involves extensive morphogenesis, proliferation and differentiation of the epithelium to give rise to the distinct cell lineages of the adult pancreas. The cell cycle molecules that specify lineage commitment within the early pancreas are unknown. We show that Cdk4 and its downstream transcription factor E2f1 regulate mouse pancreas development prior to and during the secondary transition. Cdk4 deficiency reduces embryonic pancreas size owing to impaired mesenchyme development and fewer Pdx1+ pancreatic progenitor cells. Expression of activated Cdk4R24C kinase leads to increased Nkx2.2+ and Nkx6.1+ cells and a rise in the number and proliferation of Ngn3+ endocrine precursors, resulting in expansion of the β cell lineage. We show that E2f1 binds and activates the Ngn3 promoter to modulate Ngn3 expression levels in the embryonic pancreas in a Cdk4-dependent manner. These results suggest that Cdk4 promotes β cell development by directing E2f1-mediated activation of Ngn3 and increasing the pool of endocrine precursors, and identify Cdk4 as an important regulator of early pancreas development that modulates the proliferation potential of pancreatic progenitors and endocrine precursors. PMID:21490060

  16. Attenuation of insulin resistance in rats by agmatine: role of SREBP-1c, mTOR and GLUT-2.

    Science.gov (United States)

    Sharawy, Maha H; El-Awady, Mohammed S; Megahed, Nirmeen; Gameil, Nariman M

    2016-01-01

    Insulin resistance is a serious health condition worldwide; however, its exact mechanisms are still unclear. This study investigates agmatine (AGM; an endogenous metabolite of L-arginine) effects on insulin resistance induced by high fructose diet (HFD) in rats and the possible involved mechanisms. Sprague Dawley rats were fed 60% HFD for 12 weeks, and AGM (10 mg/kg/day, orally) was given from week 9 to 12. AGM significantly reduced HFD-induced elevation in fasting insulin level, homeostasis model assessment of insulin resistance (HOMA-IR) index and liver glycogen content from 3.44-, 3.62- and 2.07- to 2.59-, 2.78- and 1.3-fold, respectively, compared to the control group, while it increased HFD-induced reduction in glucose tolerance. Additionally, AGM significantly decreased HFD-induced elevation in serum triglycerides, low density lipoprotein cholesterol and very low density lipoprotein cholesterol levels from 3.18-, 2.97- and 4.75- to 1.25-, 1.25- and 1.07-fold, respectively, compared to control group. Conversely, AGM had no significant effect on HFD-induced changes in fasting glucose, glycosylated hemoglobin, insulin tolerance and high density lipoprotein cholesterol. Furthermore, AGM significantly reduced HFD-induced elevation in mRNA expression of glucose transporter type-2 (GLUT-2), mammalian target of rapamycin (mTOR) and sterol regulatory element-binding protein-1c (SREBP-1c) without affecting that of peroxisome proliferator-activated receptor-alpha (PPAR-α) in the liver. Additionally, AGM enhanced ACh-induced aortic relaxation and attenuated liver steatosis induced by HFD. In conclusion, AGM may have a therapeutic potential in insulin resistance through suppressing SREBP-1c, mTOR and GLUT-2 in liver.

  17. Fanconi Bickel Syndrome: Novel Mutations in GLUT 2 Gene Causing a Distinguished Form of Renal Tubular Acidosis in Two Unrelated Egyptian Families

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    Mohammad Al-Haggar

    2011-01-01

    Full Text Available Background. Fanconi-Bickel syndrome (FBS is an autosomal recessive disorder caused by defects in facilitative glucose transporter 2 (GLUT2 or SLC2A2 gene mapped on chromosome 3q26.1-26.3, that codes for the glucose transporter protein 2. Methods. Two unrelated Egyptian families having suspected cases of FBS were enrolled after taking a written informed consent; both had positive consanguinity, and index cases had evidences of proximal renal tubular defects with hepatomegaly; they were subjected to history taking, signs of rickets as well as anthropometric measurements. Laboratory workup included urinalysis, renal and liver function tests including fasting and postprandial blood sugar; serum calcium, phosphorus, alkaline phosphatase, sodium and potassium, lipid profile, and detailed blood gas. Imaging including bone survey and abdominal ultrasound, and liver biopsy were done to confirm diagnosis. Molecular analysis of the GLUT2 gene was done for DNA samples extracted from peripheral blood leukocyte. All coding sequences, including flanking introns in GLUT2 gene, were amplified using PCR followed by direct sequencing. Results. Two new mutations had been detected, one in each family, in exon 3 two bases (GA were deleted (c.253 254delGA and in exon 6 in the second family, G-to-C substitution at position-1 of the splicing acceptor site (c.776-1G>C or IVS5-1G>A. Conclusion. FBS is a rare disease due to mutation in GLUT2 gene; many mutations were reported, about half were novel mutations; yet none of these mutations is more frequent. A more extensive survey for the most frequent mutations among FBS has to be contemplated to allow for use of molecular screening tests like ARMS.

  18. Role of IRS-2 in insulin and cytokine signalling.

    Science.gov (United States)

    Sun, X J; Wang, L M; Zhang, Y; Yenush, L; Myers, M G; Glasheen, E; Lane, W S; Pierce, J H; White, M F

    1995-09-14

    The protein IRS-1 acts as an interface between signalling proteins with Src-homology-2 domains (SH2 proteins) and the receptors for insulin, IGF-1, growth hormone, several interleukins (IL-4, IL-9, IL-13) and other cytokines. It regulates gene expression and stimulates mitogenesis, and appears to mediate insulin/IGF-1-stimulated glucose transport. Thus, survival of the IRS-1-/- mouse with only mild resistance to insulin was surprising. This dilemma is provisionally resolved with our discovery of a second IRS-signalling protein. We purified and cloned a likely candidate called 4PS from myeloid progenitor cells and, because of its resemblance to IRS-1, we designate it IRS-2. Alignment of the sequences of IRS-2 and IRS-1 revealed a highly conserved amino terminus containing a pleckstrin-homology domain and a phosphotyrosine-binding domain, and a poorly conserved carboxy terminus containing several tyrosine phosphorylation motifs. IRS-2 is expressed in many cells, including tissues from IRS-1-/- mice, and may be essential for signalling by several receptor systems.

  19. High-fat diet with stress impaired islets' insulin secretion by reducing plasma estradiol and pancreatic GLUT2 protein levels in rats' proestrus phase.

    Science.gov (United States)

    Salimi, M; Zardooz, H; Khodagholi, F; Rostamkhani, F; Shaerzadeh, F

    2016-10-01

    This study was conducted to determine whether two estrus phases (proestrus and diestrus) in female rats may influence the metabolic response to a high-fat diet and/or stress, focusing on pancreatic insulin secretion and content. Animals were divided into high-fat and normal diet groups, then each group was subdivided into stress and non-stress groups, and finally, each one of these was divided into proestrus and diestrus subgroups. At the end of high-fat diet treatment, foot-shock stress was applied to the animals. Then, blood samples were taken to measure plasma factors. Finally, the pancreas was removed for determination of glucose transporter 2 (GLUT2) protein levels and assessment of insulin content and secretion of the isolated islets. In the normal and high-fat diet groups, stress increased plasma corticosterone concentration in both phases. In both study phases, high-fat diet consumption decreased estradiol and increased leptin plasma levels. In the high-fat diet group in response to high glucose concentration, a reduction in insulin secretion was observed in the proestrus phase compared with the same phase in the normal diet group in the presence and absence of stress. Also, high-fat diet decreased the insulin content of islets in the proestrus phase compared with the normal diet. High-fat diet and/or stress caused a reduction in islet GLUT2 protein levels in both phases. In conclusion, it seems possible that high-fat diet alone or combined with foot-shock, predispose female rats to impaired insulin secretion, at least in part, by interfering with estradiol levels in the proestrus phase and decreasing pancreatic GLUT2 protein levels.

  20. Glucose stimulates neurotensin secretion from the rat small intestine by mechanisms involving SGLT1 and GLUT2 leading to cell depolarization and calcium influx

    DEFF Research Database (Denmark)

    Kuhre, Rune Ehrenreich; Bechmann, Louise Ellegaard; Hartmann, Bolette

    2015-01-01

    of secretion. Luminal glucose (20% wt/vol) stimulated secretion but vascular glucose (5, 10, or 15 mmol/l) was without effect. The underlying mechanisms depend on membrane depolarization and calcium influx, since the voltage-gated calcium channel inhibitor nifedipine and the KATP channel opener diazoxide......, suggesting that glucose stimulates secretion by initial uptake by this transporter. However, secretion was also sensitive to GLUT2 inhibition (by phloretin) and blockage of oxidative phosphorylation (2-4-dinitrophenol). Direct KATP channel closure by sulfonylureas stimulated secretion. Therefore, glucose...

  1. Data in support of FSH induction of IRS-2 in human granulosa cells: Mapping the transcription factor binding sites in human IRS-2 promoter

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    Surleen Kaur

    2016-03-01

    Full Text Available Insulin receptor substrate-2 (IRS-2 plays critical role in the regulation of various metabolic processes by insulin and IGF-1. The defects in its expression and/or function are linked to diseases like polycystic ovary syndrome (PCOS, insulin resistance and cancer. To predict the transcription factors (TFs responsible for the regulation of human IRS-2 gene expression, the transcription factor binding sites (TFBS and the corresponding TFs were investigated by analysis of IRS-2 promoter sequence using MatInspector Genomatix software (Cartharius et al., 2005 [1]. The ibid data is part of author׳s publication (Anjali et al., 2015 [2] that explains Follicle stimulating hormone (FSH mediated IRS-2 promoter activation in human granulosa cells and its importance in the pathophysiology of PCOS. Further analysis was carried out for binary interactions of TF regulatory genes in IRS-2 network using Cytoscape software tool and R-code. In this manuscript, we describe the methodology used for the identification of TFBSs in human IRS-2 promoter region and provide details on experimental procedures, analysis method, validation of data and also the raw files. The purpose of this article is to provide the data on all TFBSs in the promoter region of human IRS-2 gene as it has the potential for prediction of the regulation of IRS-2 gene in normal or diseased cells from patients with metabolic disorders and cancer. Keywords: IRS-2, TFBS, FSH, SP1, ChIP

  2. Diamagnetism in spinel compound CuIr2S4

    International Nuclear Information System (INIS)

    Yagasaki, K.; Nakama, T.

    2007-01-01

    The diamagnetic susceptibility in CuIr 2 S 4 is independent of temperature up to just below metal-insulator transition temperature. If activation of electrons to higher levels occurs with breaking dimer pairs, the residual electrons at the dimer position and the activated electrons to the anti-bonding orbital make localized free spins giving a Langevin paramagnetism. Assuming no magnetic interaction between the localized free spins, the susceptibility is calculated using the energy gap obtained from the conductivity assumed to be a conventional semiconductor. The calculated results cannot explain the temperature-independent diamagnetism. The real energy gap is too large for thermal electron activation, however, conduction is induced thermally over several orders of magnitude within insulating phase. From the above results, we claimed new conduction mechanism named traveling dimer conduction: dimer shifts its position by electron hopping to neighbor position without electron activation over the energy gap

  3. Inhibition of Glucose Transport by Tomatoside A, a Tomato Seed Steroidal Saponin, through the Suppression of GLUT2 Expression in Caco-2 Cells.

    Science.gov (United States)

    Li, Baorui; Terazono, Yusuke; Hirasaki, Naoto; Tatemichi, Yuki; Kinoshita, Emiko; Obata, Akio; Matsui, Toshiro

    2018-02-14

    We investigated whether tomatoside A (5α-furostane-3β,22,26-triol-3-[O-β-d-glucopyranosyl (1→2)-β-d-glucopyranosyl (1→4)-β-d-galactopyranoside] 26-O-β-d-glucopyranoside), a tomato seed saponin, may play a role in the regulation of intestinal glucose transport in human intestinal Caco-2 cells. Tomatoside A could not penetrate through Caco-2 cell monolayers, as observed in the transport experiments using liquid chromatography-mass spectrometry. The treatment of cells with 10 μM tomatoside A for 3 h resulted in a 46.0% reduction in glucose transport as compared to untreated cells. Western blotting analyses revealed that tomatoside A significantly (p transporter 2 (GLUT2) in Caco-2 cells, while no change in the expression of sodium-dependent glucose transporter 1 was observed. In glucose transport experiments, the reduced glucose transport by tomatoside A was ameliorated by a protein kinase C (PKC) inhibitor and a multidrug resistance-associated protein 2 (MRP2) inhibitor. The tomatoside A-induced reduction in glucose transport was restored in cells treated with apical sodium-dependent bile acid transporter (ASBT) siRNA or an ASBT antagonist. These findings demonstrated for the first time that the nontransportable tomato seed steroidal saponin, tomatoside A, suppressed GLUT2 expression via PKC signaling pathway during the ASBT-influx/MRP2-efflux process in Caco-2 cells.

  4. First-principles study on cubic pyrochlore iridates Y2Ir2O7 and Pr2Ir2O7

    International Nuclear Information System (INIS)

    Ishii, Fumiyuki; Mizuta, Yo Pierre; Kato, Takehiro; Ozaki, Taisuke; Weng Hongming; Onoda, Shigeki

    2015-01-01

    Fully relativistic first-principles electronic structure calculations based on a noncollinear local spin density approximation (LSDA) are performed for pyrochlore iridates Y 2 Ir 2 O 7 and Pr 2 Ir 2 O 7 . The all-in, all-out antiferromagnetic (AF) order is stablized by the on-site Coulomb repulsion U > U c in the LSDA+U scheme, with U c ∼ 1.1 eV and 1.3 eV for Y 2 Ir 2 O 7 and Pr 2 Ir 2 O 7 , respectively. AF semimetals with and without Weyl points and then a topologically trivial AF insulator successively appear with further increasing U. For U = 1.3 eV, Y 2 Ir 2 O 7 is a topologically trivial narrow-gap AF insulator having an ordered local magnetic moment ∼0.5μ B /Ir, while Pr 2 Ir 2 O 7 is barely a paramagnetic semimetal with electron and hole concentrations of 0.016/Ir, in overall agreements with experiments. With decreasing oxygen position parameter x describing the trigonal compression of IrO 6 octahedra, Pr 2 Ir 2 O 7 is driven through a non-Fermi-liquid semimetal having only an isolated Fermi point of Γ 8 + , showing a quadratic band touching, to a Z 2 topological insulator. (author)

  5. Polymorphisms in sweet taste genes (TAS1R2 and GLUT2), sweet liking, and dental caries prevalence in an adult Italian population.

    Science.gov (United States)

    Robino, Antonietta; Bevilacqua, Lorenzo; Pirastu, Nicola; Situlin, Roberta; Di Lenarda, Roberto; Gasparini, Paolo; Navarra, Chiara Ottavia

    2015-09-01

    The aim of the study was to assess the relationship between sweet taste genes and dental caries prevalence in a large sample of adults. In addition, the association between sweet liking and sugar intake with dental caries was investigated. Caries was measured by the decayed, missing, filled teeth (DMFT) index in 647 Caucasian subjects (285 males and 362 females, aged 18-65 years), coming from six villages in northeastern Italy. Sweet liking was assessed using a 9-point scale, and the mean of the liking given by each individual to specific sweet food and beverages was used to create a sweet liking score. Simple sugar consumption was estimated by a dietary history interview, considering both added sugars and sugar present naturally in foods. Our study confirmed that polymorphisms in TAS1R2 and GLUT2 genes are related to DMFT index. In particular, GG homozygous individuals for rs3935570 in TAS1R2 gene (p value = 0.0117) and GG homozygous individuals for rs1499821 in GLUT2 gene (p value = 0.0273) showed higher DMFT levels compared to both heterozygous and homozygous for the alternative allele. Furthermore, while the relationship sugar intake-DMFT did not achieve statistical significance (p value = 0.075), a significant association was identified between sweet liking and DMFT (p value = 0.004), independent of other variables. Our study showed that sweet taste genetic factors contribute to caries prevalence and highlighted the role of sweet liking as a predictor of caries risk. Therefore, these results may open new perspectives for individual risk identification and implementation of target preventive strategies, such as identifying high-risk patients before caries development.

  6. Structural, magnetic, and electronic transport properties of pyrochlore iridate Pr2Ir2O7

    Science.gov (United States)

    Kumar, Harish; Chaurasia, Rachna; Kumari, Pratibha; Paramanik, A. K.

    2018-04-01

    We have studied the structural, magnetic, and electronic transport properties of pyrochlore iridate Pr2Ir2O7. Structural investigation has been done using x-ray powder diffraction and Rietveld analysis. Pr2Ir2O7 crystallize in cubic crystallographic phase with Fd-3m space group. Temperature dependent magnetization data does not show magnetic bifurcation down to 2 K. Electrical resistivity data of Pr2Ir2O7 exhibits metallic behavior throughout temperature range. Below 50 K, a small rise in resistivity data of Pr2Ir2O7 is observed down to 12 K.

  7. Resequencing IRS2 reveals rare variants for obesity but not fasting glucose homeostasis in Hispanic children

    Science.gov (United States)

    Our objective was to resequence insulin receptor substrate 2 (IRS2) to identify variants associated with obesity- and diabetes-related traits in Hispanic children. Exonic and intronic segments, 5' and 3' flanking regions of IRS2 (approx. 14.5 kb), were bidirectionally sequenced for single nucleotide...

  8. Plk1 phosphorylation of IRS2 prevents premature mitotic exit via AKT inactivation

    Science.gov (United States)

    Chen, Long; Li, Zhiguo; Ahmad, Nihal; Liu, Xiaoqi

    2016-01-01

    Insulin receptor substrate (IRS) proteins play important roles by acting as a platform in transducing signals from transmembrane receptors upon growth factor stimulation. Although tyrosine phosphorylation on IRS proteins plays critical roles in signal transduction, phosphorylation of IRS proteins on serine/threonine residues are believed to play various regulatory roles on IRS protein function. However, studies on serine/threonine phosphorylation of IRS proteins are very limited, especially for insulin receptor substrate 2 (IRS2), one member of the IRS protein family. In this study, we identify Polo-like kinase 1 (Plk1) as the responsible kinase for phosphorylation of IRS2 on two serine residues, Ser 556 and Ser 1098. Phosphorylation of IRS2 on these two serine residues by Plk1 prevents the activation of the PI3K pathway upon growth factor stimulation by inhibiting the binding between IRS2 and the PI3K pathway components and increasing IRS2 protein degradation. Of significance, we show that IRS2 phosphorylation is cell cycle regulated and that Plk1 phosphorylation of IRS2 prevents premature mitotic exit via AKT inactivation. PMID:25830382

  9. Sulindac inhibits pancreatic carcinogenesis in LSL-KrasG12D-LSL-Trp53R172H-Pdx-1-Cre mice via suppressing aldo-keto reductase family 1B10 (AKR1B10).

    Science.gov (United States)

    Li, Haonan; Yang, Allison L; Chung, Yeon Tae; Zhang, Wanying; Liao, Jie; Yang, Guang-Yu

    2013-09-01

    Sulindac has been identified as a competitive inhibitor of aldo-keto reductase 1B10 (AKR1B10), an enzyme that plays a key role in carcinogenesis. AKR1B10 is overexpressed in pancreatic ductal adenocarcinoma (PDAC) and exhibits lipid substrate specificity, especially for farnesyl and geranylgeranyl. There have been no studies though showing that the inhibition of PDAC by sulindac is via inhibition of AKR1B10, particularly the metabolism of farnesyl/geranylgeranyl and Kras protein prenylation. To determine the chemopreventive effects of sulindac on pancreatic carcinogenesis, 5-week-old LSL-Kras(G12D)-LSL-Trp53(R172H)-Pdx-1-Cre mice (Pan(kras/p53) mice) were fed an AIN93M diet with or without 200 p.p.m. sulindac (n = 20/group). Kaplan-Meier survival analysis showed that average animal survival in Pan(kras/p53) mice was 143.7 ± 8.8 days, and average survival with sulindac was increased to 168.0 ± 8.8 days (P < 0.005). Histopathological analyses revealed that 90% of mice developed PDAC, 10% with metastasis to the liver and lymph nodes. With sulindac, the incidence of PDAC was reduced to 56% (P < 0.01) and only one mouse had lymph node metastasis. Immunochemical analysis showed that sulindac significantly decreased Ki-67-labeled cell proliferation and markedly reduced the expression of phosphorylated extracellular signal-regulated kinases 1 and 2 (ERK1/2), c-Raf and mitogen-activated protein kinase kinase 1 and 2. In in vitro experiments with PDAC cells from Pan(kras/p53) mice, sulindac exhibited dose-dependent inhibition of AKR1B10 activity. By silencing AKR1B10 expression through small interfering RNA or by sulindac treatment, these in vitro models showed a reduction in Kras and human DNA-J homolog 2 protein prenylation, and downregulation of phosphorylated C-raf, ERK1/2 and MEK1/2 expression. Our results demonstrate that sulindac inhibits pancreatic carcinogenesis by the inhibition of Kras protein prenylation by targeting AKR1B10.

  10. PPAR-γ activation increases insulin secretion through the up-regulation of the free fatty acid receptor GPR40 in pancreatic β-cells.

    Directory of Open Access Journals (Sweden)

    Hyo-Sup Kim

    Full Text Available BACKGROUND: It has been reported that peroxisome proliferator-activated receptor (PPAR-γ and their synthetic ligands have direct effects on pancreatic β-cells. We investigated whether PPAR-γ activation stimulates insulin secretion through the up-regulation of GPR40 in pancreatic β-cells. METHODS: Rat insulinoma INS-1 cells and primary rat islets were treated with rosiglitazone (RGZ and/or adenoviral PPAR-γ overexpression. OLETF rats were treated with RGZ. RESULTS: PPAR-γ activation with RGZ and/or adenoviral PPAR-γ overexpression increased free fatty acid (FFA receptor GPR40 expression, and increased insulin secretion and intracellular calcium mobilization, and was blocked by the PLC inhibitors, GPR40 RNA interference, and GLUT2 RNA interference. As a downstream signaling pathway of intracellular calcium mobilization, the phosphorylated levels of CaMKII and CREB, and the downstream IRS-2 and phospho-Akt were significantly increased. Despite of insulin receptor RNA interference, the levels of IRS-2 and phospho-Akt was still maintained with PPAR-γ activation. In addition, the β-cell specific gene expression, including Pdx-1 and FoxA2, increased in a GPR40- and GLUT2-dependent manner. The levels of GPR40, phosphorylated CaMKII and CREB, and β-cell specific genes induced by RGZ were blocked by GW9662, a PPAR-γ antagonist. Finally, PPAR-γ activation up-regulated β-cell gene expressions through FoxO1 nuclear exclusion, independent of the insulin signaling pathway. Based on immunohistochemical staining, the GLUT2, IRS-2, Pdx-1, and GPR40 were more strongly expressed in islets from RGZ-treated OLETF rats compared to control islets. CONCLUSION: These observations suggest that PPAR-γ activation with RGZ and/or adenoviral overexpression increased intracellular calcium mobilization, insulin secretion, and β-cell gene expression through GPR40 and GLUT2 gene up-regulation.

  11. The yo-yo IR2 test: physiological response, reliability, and application to elite soccer

    DEFF Research Database (Denmark)

    Krustrup, Peter; Mohr, Magni; Nybo, Lars

    2006-01-01

    biopsies and blood samples were obtained, and heart rate was measured before, during, and after the Yo-Yo IR2 test. Additionally, 119 Scandinavian elite soccer players carried out the Yo-Yo IR2 test on two to four occasions. Results: Yo-Yo IR2 performance was 591 +/- 43 (320-920) m or 4.3 (2.6-7.9) min...... was better (P elite soccer players than for moderate elite players (1059 +/- 35 vs 771 +/- 26 m) and better (P elite soccer players...... turnover. Specifically, the Yo-Yo IR2 test was shown to be a sensitive tool to differentiate between intermittent exercise performance of soccer players in different seasonal periods and at different competitive levels and playing positions....

  12. Yo-Yo IR2 testing of elite and sub-elite soccer players

    DEFF Research Database (Denmark)

    Ingebrigtsen, Jørgen; Bendiksen, Mads; Randers, Morten Bredsgaard

    2012-01-01

    Abstract We examined performance, heart rate response and construct validity of the Yo-Yo IR2 test by testing 111 elite and 92 sub-elite soccer players from Norway and Denmark. VO(2)max, Yo-Yo IR1 and repeated sprint tests (RSA) (n = 51) and match-analyses (n = 39) were also performed. Yo-Yo IR2...

  13. FGT-1 is a mammalian GLUT2-like facilitative glucose transporter in Caenorhabditis elegans whose malfunction induces fat accumulation in intestinal cells.

    Directory of Open Access Journals (Sweden)

    Shun Kitaoka

    Full Text Available Caenorhabditis elegans (C. elegans is an attractive animal model for biological and biomedical research because it permits relatively easy genetic dissection of cellular pathways, including insulin/IGF-like signaling (IIS, that are conserved in mammalian cells. To explore C. elegans as a model system to study the regulation of the facilitative glucose transporter (GLUT, we have characterized the GLUT gene homologues in C. elegans: fgt-1, R09B5.11, C35A11.4, F53H8.3, F48E3.2, F13B12.2, Y61A9LA.1, K08F9.1 and Y37A1A.3. The exogenous expression of these gene products in Xenopus oocytes showed transport activity to unmetabolized glucose analogue 2-deoxy-D-glucose only in FGT-1. The FGT-1-mediated transport activity was inhibited by the specific GLUT inhibitor phloretin and exhibited a Michaelis constant (Km of 2.8 mM. Mannose, galactose, and fructose were able to inhibit FGT-1-mediated 2-deoxy-D-glucose uptake (P < 0.01, indicating that FGT-1 is also able to transport these hexose sugars. A GFP fusion protein of FGT-1 was observed only on the basolateral membrane of digestive tract epithelia in C. elegans, but not in other tissues. FGT-1::eGFP expression was observed from early embryonic stages. The knockdown or mutation of fgt-1 resulted in increased fat staining in both wild-type and daf-2 (mammalian insulin receptor homologue mutant animals. Other common phenotypes of IIS mutant animals, including dauer formation and brood size reduction, were not affected by fgt-1 knockdown in wild-type or daf-2 mutants. Our results indicated that in C. elegans, FGT-1 is mainly a mammalian GLUT2-like intestinal glucose transporter and is involved in lipid metabolism.

  14. Crystallization and diffraction analysis of the serpin IRS-2 from the hard tick Ixodes ricinus

    International Nuclear Information System (INIS)

    Kovářová, Zuzana; Chmelař, Jindřich; Šanda, Miloslav; Brynda, Jiří; Mareš, Michael; Řezáčová, Pavlína

    2010-01-01

    Cleavage of the serpin IRS-2 from the hard tick I. ricinus by contaminating proteolytic activity mimicked the specific processing of the serpin by its target protease and resulted in a more stable form of the serpin which produced crystals that diffracted to 1.8 Å resolution. IRS-2 from the hard tick Ixodes ricinus belongs to the serpin family of protease inhibitors. It is produced in the salivary glands of the tick and its anti-inflammatory activity suggests that it plays a role in parasite–host interaction. Recombinant IRS-2 prepared by heterologous expression in a bacterial system was crystallized using the hanging-drop vapour-diffusion method. The crystals belonged to the primitive tetragonal space group P4 3 and diffracted to 1.8 Å resolution. Mass-spectrometric and electrophoretic analyses revealed that IRS-2 was cleaved by contaminating proteases during crystallization. This processing of IRS-2 mimicked the specific cleavage of the serpin by its target protease and resulted in a more stable form (the so-called relaxed conformation), which produced well diffracting crystals. Activity profiling with specific substrates and inhibitors demonstrated traces of serine and cysteine proteases in the protein stock solution

  15. Deletion of Irs2 causes reduced kidney size in mice: role for inhibition of GSK3beta?

    LENUS (Irish Health Repository)

    Carew, Rosemarie M.

    2010-07-06

    Abstract Background Male Irs2-\\/- mice develop fatal type 2 diabetes at 13-14 weeks. Defects in neuronal proliferation, pituitary development and photoreceptor cell survival manifest in Irs2-\\/- mice. We identify retarded renal growth in male and female Irs2-\\/- mice, independent of diabetes. Results Kidney size and kidney:body weight ratio were reduced by approximately 20% in Irs2-\\/- mice at postnatal day 5 and was maintained in maturity. Reduced glomerular number but similar glomerular density was detected in Irs2-\\/- kidney compared to wild-type, suggesting intact global kidney structure. Analysis of insulin signalling revealed renal-specific upregulation of PKBβ\\/Akt2, hyperphosphorylation of GSK3β and concomitant accumulation of β-catenin in Irs2-\\/- kidney. Despite this, no significant upregulation of β-catenin targets was detected. Kidney-specific increases in Yes-associated protein (YAP), a key driver of organ size were also detected in the absence of Irs2. YAP phosphorylation on its inhibitory site Ser127 was also increased, with no change in the levels of YAP-regulated genes, suggesting that overall YAP activity was not increased in Irs2-\\/- kidney. Conclusions In summary, deletion of Irs2 causes reduced kidney size early in mouse development. Compensatory mechanisms such as increased β-catenin and YAP levels failed to overcome this developmental defect. These data point to Irs2 as an important novel mediator of kidney size.

  16. ZnIr2O4: An efficient photocatalyst with Rashba splitting

    KAUST Repository

    Singh, Nirpendra; Schwingenschlö gl, Udo

    2013-01-01

    spin splitting of 220 meV Å. The valence band edge potential is 2.89 V against the standard hydrogen electrode, which is sufficient for photocatalytic water oxidation and pollutant degradation. The optical absorption of S-doped ZnIr2O4 is strongly

  17. Single-nucleotide polymorphism of INS, INSR, IRS1, IRS2, PPAR-G ...

    Indian Academy of Sciences (India)

    2017-03-02

    Mar 2, 2017 ... Abstract. Polycystic ovary syndrome (PCOS) is the most common and a complex female endocrine disorder, and is one of the leading cause of female infertility. Here, we aimed to investigate the association of single-nucleotide polymorphism of INS, INSR,. IRS1, IRS2, PPAR-G and CAPN10 gene in the ...

  18. ZnIr2O4: An efficient photocatalyst with Rashba splitting

    KAUST Repository

    Singh, Nirpendra

    2013-11-01

    Semiconductor-based photocatalysts nowadays are of central interest for the splitting of water into hydrogen and oxygen. However, the efficiency of the known materials is small for direct utilization of the solar energy. Using first-principles calculations, we show that ZnIr2O4 can overcome this shortage. Modified Becke-Johnson calculations give an indirect band of 2.25 eV, which can be reduced to the visible energy range by S doping. For 25% S doping we find a direct band gap of 1.25 eV and a Rashba spin splitting of 220 meV Å. The valence band edge potential is 2.89 V against the standard hydrogen electrode, which is sufficient for photocatalytic water oxidation and pollutant degradation. The optical absorption of S-doped ZnIr2O4 is strongly enhanced, making the material an efficient photocatalyst for visible light. © 2013 EPLA.

  19. Negative Longitudinal Magnetoresistance in the Density Wave Phase of Y_{2}Ir_{2}O_{7}.

    Science.gov (United States)

    Juyal, Abhishek; Agarwal, Amit; Mukhopadhyay, Soumik

    2018-03-02

    The ground state of nanowires of single-crystalline pyrochlore Y_{2}Ir_{2}O_{7} is a density wave. The application of a transverse magnetic field increases the threshold electric field for the collective depinning of the density wave state at a low temperature, leading to colossal magnetoresistance for voltages around the depinning threshold. This is in striking contrast to the case where even a vanishingly small longitudinal magnetic field sharply reduces the depinning threshold voltage, resulting in negative magnetoresistance. Ruling out several other possibilities, we argue that this phenomenon is likely to be a consequence of the chiral anomaly in the gapped out Weyl semimetal phase in Y_{2}Ir_{2}O_{7}.

  20. Negative Longitudinal Magnetoresistance in the Density Wave Phase of Y2Ir2O7

    Science.gov (United States)

    Juyal, Abhishek; Agarwal, Amit; Mukhopadhyay, Soumik

    2018-03-01

    The ground state of nanowires of single-crystalline pyrochlore Y2Ir2O7 is a density wave. The application of a transverse magnetic field increases the threshold electric field for the collective depinning of the density wave state at a low temperature, leading to colossal magnetoresistance for voltages around the depinning threshold. This is in striking contrast to the case where even a vanishingly small longitudinal magnetic field sharply reduces the depinning threshold voltage, resulting in negative magnetoresistance. Ruling out several other possibilities, we argue that this phenomenon is likely to be a consequence of the chiral anomaly in the gapped out Weyl semimetal phase in Y2Ir2O7 .

  1. Electronic Structures of Reduced and Superreduced Ir2(1,8-diisocyanomenthane)4 n+ Complexes

    Czech Academy of Sciences Publication Activity Database

    Záliš, Stanislav; Hunter, B. M.; Gray, H. B.; Vlček, Antonín

    2017-01-01

    Roč. 56, č. 5 (2017), s. 2874-2883 ISSN 0020-1669 R&D Projects: GA MŠk LD14129 Grant - others:COST(XE) CM1405; COST(XE) CM1202 Institutional support: RVO:61388955 Keywords : electronic structure * electrochemistry * Ir2(1,8-diisocyanomenthane)4 n+ Complexes Subject RIV: CG - Electrochemistry OBOR OECD: Physical chemistry Impact factor: 4.857, year: 2016

  2. Limb darkening in Venus night-side disk as viewed from Akatsuki IR2

    Science.gov (United States)

    Satoh, Takehiko; Nakakushi, Takashi; Sato, Takao M.; Hashimoto, George L.

    2017-10-01

    Night-side hemisphere of Venus exhibits dark and bright regions as a result of spatially inhomogeneous cloud opacity which is illuminated by infrared radiation from deeper atmosphere. The 2-μm camera (IR2) onboard Akatsuki, Japan's Venus Climate Orbiter, is equipped with three narrow-band filters (1.735, 2.26, and 2.32 μm) to image Venus night-side disk in well-known transparency windows of CO2 atmosphere (Allen and Crawford 1984). In general, a cloud feature appears brightest when it is in the disk center and becomes darker as the zenith angle of emergent light increases. Such limb darkening was observed with Galileo/NIMS and mathematically approximated (Carlson et al., 1993). Limb-darkening correction helps to identify branches, in a 1.74-μm vs. 2.3-μm radiances scatter plot, each of which corresponds to a group of aerosols with similar properties. We analyzed Akatsuki/IR2 images to characterize the limb darkening for three night-side filters.There is, however, contamination from the intense day-side disk blurred by IR2's point spread function (PSF). It is found that infrared light can be multiplly reflected within the Si substrate of IR2 detector (1024x1024 pixels PtSi array), causing elongated tail in the actual PSF. We treated this in two different ways. One is to mathematically approximate the PSF (with a combination of modified Lorentz functions) and another is to differentiate 2.26-μm image from 2.32-μm image so that the blurred light pattern can directly be obtained. By comparing results from these two methods, we are able to reasonablly clean up the night-side images and limb darkening is extracted. Physical interpretation of limb darkening, as well as "true" time variations of cloud brightness will be presented/discussed.

  3. Effect of stoichiometry on magnetic and transport properties in polycrystalline Y2Ir2O7

    Science.gov (United States)

    Dwivedi, Vinod Kumar; Mukhopadhyay, Soumik

    2018-05-01

    In this paper we discuss synthesis of polycrystalline Y2Ir2O7 by solid state reaction route. XRD analysis shows deviation from stoichiometry which is also confirmed by SEM-EDX analysis. SEM analysis indicates average particle size ranging from 100 nm to 800 µm. EDX analysis gives clear evidence for deviation of stoichiometry of the product. Magnetic analysis is indicating effect of stoichiometry and showing ferromagnetic interaction unlike antiferromagnetic feature. Electrical resistivity is showing similar behavior as reported earlier and reveals no effect of different size of grains or grain boundaries from room temperature to 125 K.

  4. Inhibition of PTP1B Restores IRS1-Mediated Hepatic Insulin Signaling in IRS2-Deficient Mice

    Science.gov (United States)

    González-Rodríguez, Águeda; Gutierrez, Jose A. Mas; Sanz-González, Silvia; Ros, Manuel; Burks, Deborah J.; Valverde, Ángela M.

    2010-01-01

    OBJECTIVE Mice with complete deletion of insulin receptor substrate 2 (IRS2) develop hyperglycemia, impaired hepatic insulin signaling, and elevated gluconeogenesis, whereas mice deficient for protein tyrosine phosphatase (PTP)1B display an opposing hepatic phenotype characterized by increased sensitivity to insulin. To define the relationship between these two signaling pathways in the regulation of liver metabolism, we used genetic and pharmacological approaches to study the effects of inhibiting PTP1B on hepatic insulin signaling and expression of gluconeogenic enzymes in IRS2−/− mice. RESEARCH DESIGN AND METHODS We analyzed glucose homeostasis and insulin signaling in liver and isolated hepatocytes from IRS2−/− and IRS2−/−/PTP1B−/− mice. Additionally, hepatic insulin signaling was assessed in control and IRS2−/− mice treated with resveratrol, an antioxidant present in red wine. RESULTS In livers of hyperglycemic IRS2−/− mice, the expression levels of PTP1B and its association with the insulin receptor (IR) were increased. The absence of PTP1B in the double-mutant mice restored hepatic IRS1-mediated phosphatidylinositol (PI) 3-kinase/Akt/Foxo1 signaling. Moreover, resveratrol treatment of hyperglycemic IRS2−/− mice decreased hepatic PTP1B mRNA and inhibited PTP1B activity, thereby restoring IRS1-mediated PI 3-kinase/Akt/Foxo1 signaling and peripheral insulin sensitivity. CONCLUSIONS By regulating the phosphorylation state of IR, PTB1B determines sensitivity to insulin in liver and exerts a unique role in the interplay between IRS1 and IRS2 in the modulation of hepatic insulin action. PMID:20028942

  5. Overexpression of IRS2 in isolated pancreatic islets causes proliferation and protects human β-cells from hyperglycemia-induced apoptosis

    International Nuclear Information System (INIS)

    Mohanty, S.; Spinas, G.A.; Maedler, K.; Zuellig, R.A.; Lehmann, R.; Donath, M.Y.; Trueb, T.; Niessen, M.

    2005-01-01

    Studies in vivo indicate that IRS2 plays an important role in maintaining functional β-cell mass. To investigate if IRS2 autonomously affects β-cells, we have studied proliferation, apoptosis, and β-cell function in isolated rat and human islets after overexpression of IRS2 or IRS1. We found that β-cell proliferation was significantly increased in rat islets overexpressing IRS2 while IRS1 was less effective. Moreover, proliferation of a β-cell line, INS-1, was decreased after repression of Irs2 expression using RNA oligonucleotides. Overexpression of IRS2 in human islets significantly decreased apoptosis of β-cells, induced by 33.3 mM D-glucose. However, IRS2 did not protect cultured rat islets against apoptosis in the presence of 0.5 mM palmitic acid. Overexpression of IRS2 in isolated rat islets significantly increased basal and D-glucose-stimulated insulin secretion as determined in perifusion experiments. Therefore, IRS2 is sufficient to induce proliferation in rat islets and to protect human β-cells from D-glucose-induced apoptosis. In addition, IRS2 can improve β-cell function. Our results indicate that IRS2 acts autonomously in β-cells in maintenance and expansion of functional β-cell mass in vivo

  6. Distinct signalling properties of insulin receptor substrate (IRS)-1 and IRS-2 in mediating insulin/IGF-1 action

    DEFF Research Database (Denmark)

    Rabiee, Atefeh; Krüger, Marcus; Ardenkjær-Larsen, Jacob

    2018-01-01

    Insulin/IGF-1 action is driven by a complex and highly integrated signalling network. Loss-of-function studies indicate that the major insulin/IGF-1 receptor substrate (IRS) proteins, IRS-1 and IRS-2, mediate different biological functions in vitro and in vivo, suggesting specific signalling...... properties despite their high degree of homology. To identify mechanisms contributing to the differential signalling properties of IRS-1 and IRS-2 in the mediation of insulin/IGF-1 action, we performed comprehensive mass spectrometry (MS)-based phosphoproteomic profiling of brown preadipocytes from wild type......, IRS-1-/-and IRS-2-/-mice in the basal and IGF-1-stimulated states. We applied stable isotope labeling by amino acids in cell culture (SILAC) for the accurate quantitation of changes in protein phosphorylation. We found ~10% of the 6262 unique phosphorylation sites detected to be regulated by IGF-1...

  7. Optical Response of Cu1-xZnxIr2S4 Due to Metal--Insulator Transition

    International Nuclear Information System (INIS)

    Chen, L.; Matsunami, M.; Nanba, T.; Cao, G.; Suzuki, H.; Isobe, M.; Matsumoto, T.

    2003-01-01

    The mother material CuIr 2 S 4 of the thiospinel system Cu 1-x Zn x Ir 2 S 4 undergoes a temperature-induced metal--insulator (Mi) transition. We report the temperature dependence of the optical reflection spectra of Cu 1-x Zn x Ir 2 S 4 (x ≤ 0.5) at the temperatures of 8-300 K in the energy regions of 0.005--30 eV in order to study the change in the electronic structure due to the Zn substitution for Cu. Zn substitution induced mainly the splitting of the hybridization band between the Ir-5d(t 2g ) and S-3 p states crossing the E F . Obtained optical conductivity (σ ) spectrum is discussed in relation to the change in the electronic structure close to the E F . (author)

  8. High-frequency effects in antiferromagnetic Sr3Ir2O7

    Science.gov (United States)

    Williamson, Morgan; Seinige, Heidi; Shen, Shida; Wang, Cheng; Cao, Gang; Zhou, Jianshi; Goodenough, John; Tsoi, Maxim

    Antiferromagnetic (AFM) spintronics is one of many promising routes for `beyond the CMOS' technologies where unique properties of AFM materials are exploited to achieve new and improved functionalities. AFMs are especially interesting for high-speed memory applications thanks to their high natural frequencies. Here we report the effects of high-frequency (microwave) currents on transport properties of antiferromagnetic Mott insulator Sr3Ir2O7. The microwaves at 3-7 GHz were found to affect the material's current-voltage characteristic and produce resonance-like features that we tentatively associate with the dissipationless magnonics recently predicted to occur in antiferromagnetic insulators subject to ac electric fields. Our observations support the potential of antiferromagnetic materials for high-speed/high-frequency spintronic applications. This work was supported in part by C-SPIN, one of six centers of STARnet, a Semiconductor Research Corporation program, sponsored by MARCO and DARPA, by NSF Grants DMR-1207577, DMR-1265162, DMR-1600057, and DMR-1122603, and by the King Abdullah University of Science and Technology (KAUST) Office of Sponsored Research (OSR) under Award No. OSR-2015-CRG4-2626.

  9. Glucose Induces Mouse β-Cell Proliferation via IRS2, MTOR, and Cyclin D2 but Not the Insulin Receptor

    Science.gov (United States)

    Stamateris, Rachel E.; Sharma, Rohit B.; Kong, Yahui; Ebrahimpour, Pantea; Panday, Deepika; Ranganath, Pavana; Zou, Baobo; Levitt, Helena; Parambil, Nisha Abraham; O’Donnell, Christopher P.; García-Ocaña, Adolfo

    2016-01-01

    An important goal in diabetes research is to understand the processes that trigger endogenous β-cell proliferation. Hyperglycemia induces β-cell replication, but the mechanism remains debated. A prime candidate is insulin, which acts locally through the insulin receptor. Having previously developed an in vivo mouse hyperglycemia model, we tested whether glucose induces β-cell proliferation through insulin signaling. By using mice lacking insulin signaling intermediate insulin receptor substrate 2 (IRS2), we confirmed that hyperglycemia-induced β-cell proliferation requires IRS2 both in vivo and ex vivo. Of note, insulin receptor activation was not required for glucose-induced proliferation, and insulin itself was not sufficient to drive replication. Glucose and insulin caused similar acute signaling in mouse islets, but chronic signaling differed markedly, with mammalian target of rapamycin (MTOR) and extracellular signal–related kinase (ERK) activation by glucose and AKT activation by insulin. MTOR but not ERK activation was required for glucose-induced proliferation. Cyclin D2 was necessary for glucose-induced β-cell proliferation. Cyclin D2 expression was reduced when either IRS2 or MTOR signaling was lost, and restoring cyclin D2 expression rescued the proliferation defect. Human islets shared many of these regulatory pathways. Taken together, these results support a model in which IRS2, MTOR, and cyclin D2, but not the insulin receptor, mediate glucose-induced proliferation. PMID:26740601

  10. Distinct signalling properties of insulin receptor substrate (IRS)-1 and IRS-2 in mediating insulin/IGF-1 action.

    Science.gov (United States)

    Rabiee, Atefeh; Krüger, Marcus; Ardenkjær-Larsen, Jacob; Kahn, C Ronald; Emanuelli, Brice

    2018-07-01

    Insulin/IGF-1 action is driven by a complex and highly integrated signalling network. Loss-of-function studies indicate that the major insulin/IGF-1 receptor substrate (IRS) proteins, IRS-1 and IRS-2, mediate different biological functions in vitro and in vivo, suggesting specific signalling properties despite their high degree of homology. To identify mechanisms contributing to the differential signalling properties of IRS-1 and IRS-2 in the mediation of insulin/IGF-1 action, we performed comprehensive mass spectrometry (MS)-based phosphoproteomic profiling of brown preadipocytes from wild type, IRS-1 -/- and IRS-2 -/- mice in the basal and IGF-1-stimulated states. We applied stable isotope labeling by amino acids in cell culture (SILAC) for the accurate quantitation of changes in protein phosphorylation. We found ~10% of the 6262 unique phosphorylation sites detected to be regulated by IGF-1. These regulated sites included previously reported substrates of the insulin/IGF-1 signalling pathway, as well as novel substrates including Nuclear Factor I X and Semaphorin-4B. In silico prediction suggests the protein kinase B (PKB), protein kinase C (PKC), and cyclin-dependent kinase (CDK) as the main mediators of these phosphorylation events. Importantly, we found preferential phosphorylation patterns depending on the presence of either IRS-1 or IRS-2, which was associated with specific sets of kinases involved in signal transduction downstream of these substrates such as PDHK1, MAPK3, and PKD1 for IRS-1, and PIN1 and PKC beta for IRS-2. Overall, by generating a comprehensive phosphoproteomic profile from brown preadipocyte cells in response to IGF-1 stimulation, we reveal both common and distinct insulin/IGF-1 signalling events mediated by specific IRS proteins. Copyright © 2018 Elsevier Inc. All rights reserved.

  11. Overexpression of Insig-1 protects β cell against glucolipotoxicity via SREBP-1c

    Directory of Open Access Journals (Sweden)

    Chen Ke

    2011-08-01

    Full Text Available Abstract Background High glucose induced lipid synthesis leads to β cell glucolipotoxicity. Sterol regulatory element binding protein-1c (SREBP-1c is reported to be partially involved in this process. Insulin induced gene-1 (Insig-1 is an important upstream regulator of Insig-1-SREBPs cleavage activating protein (SCAP-SREBP-1c pathway. Insig-1 effectively blocks the transcription of SREBP-1c, preventing the activation of the genes for lipid biosynthesis. In this study, we aimed to investigate whether Insig-1 protects β cells against glucolipotoxicity. Methods An Insig-1 stable cell line was generated by overexpression of Insig-1 in INS-1 cells. The expression of Insig-1 was evaluated by RT-PCR and Western blotting, then, cells were then treated with standard (11.2 mM or high (25.0 mM glucose for 0 h, 24 h and 72 h. Cell viability, apoptosis, glucose stimulated insulin secretion (GSIS, lipid metabolism and mRNA expression of insulin secretion relevant genes such as IRS-2, PDX-1, GLUT-2, Insulin and UCP-2 were evaluated. Results We found that Insig-1 suppressed the high glucose induced SREBP-1c mRNA and protein expression. Our results also showed that Insig-1 overexpression protected β cells from ER stress-induced apoptosis by regulating the proteins expressed in the IRE1α pathway, such as p-IRE1α, p-JNK, CHOP and BCL-2. In addition, Insig-1 up-regulated the expression of IRS-2, PDX-1, GLUT-2 and Insulin, down-regulated the expression of UCP-2 and improved glucose stimulated insulin secretion (GSIS. Finally, we found that Insig-1 inhibited the lipid accumulation and free fatty acid (FFA synthesis in a time-dependent manner. Conclusions There results suggest that Insig-1 may play a critical role in protecting β cells against glucolipotoxicity by regulating the expression of SREBP-1c.

  12. Persistent low-temperature spin dynamics in the mixed-valence iridate Ba3InIr2O9

    Science.gov (United States)

    Dey, Tusharkanti; Majumder, M.; Orain, J. C.; Senyshyn, A.; Prinz-Zwick, M.; Bachus, S.; Tokiwa, Y.; Bert, F.; Khuntia, P.; Büttgen, N.; Tsirlin, A. A.; Gegenwart, P.

    2017-11-01

    Using thermodynamic measurements, neutron diffraction, nuclear magnetic resonance, and muon spin relaxation, we establish putative quantum spin-liquid behavior in Ba3InIr2O9 , where unpaired electrons are localized on mixed-valence Ir2O9 dimers with Ir4.5 + ions. Despite the antiferromagnetic Curie-Weiss temperature on the order of 10 K, neither long-range magnetic order nor spin freezing are observed down to at least 20 mK, such that spins are short-range correlated and dynamic over nearly three decades in temperature. Quadratic power-law behavior of both the spin-lattice relaxation rate and specific heat indicates the gapless nature of the ground state. We envisage that this exotic behavior may be related to an unprecedented combination of the triangular and buckled honeycomb geometries of nearest-neighbor exchange couplings in the mixed-valence setting.

  13. Synthesis, Structure, and Rigid Unit Mode-like Anisotropic Thermal Expansion of BaIr2In9.

    Science.gov (United States)

    Calta, Nicholas P; Han, Fei; Kanatzidis, Mercouri G

    2015-09-08

    This Article reports the synthesis of large single crystals of BaIr2In9 using In flux and their characterization by variable-temperature single-crystal and synchrotron powder X-ray diffraction, resistivity, and magnetization measurements. The title compound adopts the BaFe2Al9-type structure in the space group P6/mmm with room temperature unit cell parameters a = 8.8548(6) Å and c = 4.2696(4) Å. BaIr2In9 exhibits anisotropic thermal expansion behavior with linear expansion along the c axis more than 3 times larger than expansion in the ab plane between 90 and 400 K. This anisotropic expansion originates from a rigid unit mode-like mechanism similar to the mechanism of zero and negative thermal expansion observed in many anomalous thermal expansion materials such as ZrW2O8 and ScF3.

  14. Magnetic Excitations across the Metal-Insulator Transition in the Pyrochlore Iridate Eu2Ir2O7

    Science.gov (United States)

    Chun, Sae Hwan; Yuan, Bo; Casa, Diego; Kim, Jungho; Kim, Chang-Yong; Tian, Zhaoming; Qiu, Yang; Nakatsuji, Satoru; Kim, Young-June

    2018-04-01

    We report a resonant inelastic x-ray scattering study of the magnetic excitation spectrum in a highly insulating Eu2 Ir2 O7 single crystal that exhibits a metal-insulator transition at TMI=111 (7 ) K . A propagating magnon mode with a 20 meV bandwidth and a 28 meV magnon gap is found in the excitation spectrum at 7 K, which is expected in the all-in-all-out magnetically ordered state. This magnetic excitation exhibits substantial softening as the temperature is raised towards TMI and turns into a highly damped excitation in the paramagnetic phase. Remarkably, the softening occurs throughout the whole Brillouin zone including the zone boundary. This observation is inconsistent with the magnon renormalization expected in a local moment system and indicates that the strength of the electron correlation in Eu2 Ir2 O7 is only moderate, so that electron itinerancy should be taken into account in describing its magnetism.

  15. The effect of defects and disorder on the electronic properties of ZnIr2O4

    International Nuclear Information System (INIS)

    Ramo, David Muñoz; Bristowe, Paul D.

    2014-01-01

    We analyze by means of ab initio calculations the role of imperfections on the electronic structure of ZnIr 2 O 4 , ranging from point defects in the spinel phase to the fully amorphous phase. We find that interstitial defects and anion vacancies in the spinel have large formation energies, in agreement with the trends observed in other spinels. In contrast, cation vacancies and antisites have lower formation energies. Among them, the zinc antisite and the zinc vacancy are the defects with the lowest formation energy. They are found to act as acceptors, and may be responsible for the spontaneous hole doping in the material. They may also induce optical transitions that would reduce the transparency of the material. Amorphization of ZnIr 2 O 4 leads a large decrease of the band gap and appearance of localized states at the edges of the band gap region, which may act as charge traps and prevent amorphous ZnIr 2 O 4 from being a good hole conductor

  16. Resequencing of IRS2 reveals rare variants for obesity but not fasting glucose homeostasis in Hispanic children.

    Science.gov (United States)

    Butte, Nancy F; Voruganti, V Saroja; Cole, Shelley A; Haack, Karin; Comuzzie, Anthony G; Muzny, Donna M; Wheeler, David A; Chang, Kyle; Hawes, Alicia; Gibbs, Richard A

    2011-09-22

    Our objective was to resequence insulin receptor substrate 2 (IRS2) to identify variants associated with obesity- and diabetes-related traits in Hispanic children. Exonic and intronic segments, 5' and 3' flanking regions of IRS2 (∼14.5 kb), were bidirectionally sequenced for single nucleotide polymorphism (SNP) discovery in 934 Hispanic children using 3730XL DNA Sequencers. Additionally, 15 SNPs derived from Illumina HumanOmni1-Quad BeadChips were analyzed. Measured genotype analysis tested associations between SNPs and obesity and diabetes-related traits. Bayesian quantitative trait nucleotide analysis was used to statistically infer the most likely functional polymorphisms. A total of 140 SNPs were identified with minor allele frequencies (MAF) ranging from 0.001 to 0.47. Forty-two of the 70 coding SNPs result in nonsynonymous amino acid substitutions relative to the consensus sequence; 28 SNPs were detected in the promoter, 12 in introns, 28 in the 3'-UTR, and 2 in the 5'-UTR. Two insertion/deletions (indels) were detected. Ten independent rare SNPs (MAF = 0.001-0.009) were associated with obesity-related traits (P = 0.01-0.00002). SNP 10510452_139 in the promoter region was shown to have a high posterior probability (P = 0.77-0.86) of influencing BMI, fat mass, and waist circumference in Hispanic children. SNP 10510452_139 contributed between 2 and 4% of the population variance in body weight and composition. None of the SNPs or indels were associated with diabetes-related traits or accounted for a previously identified quantitative trait locus on chromosome 13 for fasting serum glucose. Rare but not common IRS2 variants may play a role in the regulation of body weight but not an essential role in fasting glucose homeostasis in Hispanic children.

  17. Identification of functional domains of the IR2 protein of equine herpesvirus 1 required for inhibition of viral gene expression and replication

    International Nuclear Information System (INIS)

    Kim, Seong K.; Kim, Seongman; Dai Gan; Zhang Yunfei; Ahn, Byung C.; O'Callaghan, Dennis J.

    2011-01-01

    The equine herpesvirus 1 (EHV-1) negative regulatory IR2 protein (IR2P), an early 1,165-amino acid (aa) truncated form of the 1487-aa immediate-early protein (IEP), lacks the trans-activation domain essential for IEP activation functions but retains domains for binding DNA, TFIIB, and TBP and the nuclear localization signal. IR2P mutants of the N-terminal region which lack either DNA-binding activity or TFIIB-binding activity were unable to down-regulate EHV-1 promoters. In EHV-1-infected cells expressing full-length IR2P, transcription and protein expression of viral regulatory IE, early EICP0, IR4, and UL5, and late ETIF genes were dramatically inhibited. Viral DNA levels were reduced to 2.1% of control infected cells, but were vey weakly affected in cells that express the N-terminal 706 residues of IR2P. These results suggest that IR2P function requires the two N-terminal domains for binding DNA and TFIIB as well as the C-terminal residues 707 to 1116 containing the TBP-binding domain. - Highlights: → We examine the functional domains of IR2P that mediates negative regulation. → IR2P inhibits at the transcriptional level. → DNA-binding mutant or TFIIB-binding mutant fails to inhibit. → C-terminal aa 707 to 1116 are required for full inhibition. → Inhibition requires the DNA-binding domain, TFIIB-binding domain, and C-terminus.

  18. Probing the spin-orbit Mott state in Sr3Ir2O7 by electron doping

    Science.gov (United States)

    Hogan, Thomas C.

    Iridium-based members of the Ruddlesden-Popper family of oxide compounds are characterized by a unique combination of energetically comparable effects: crystal-field splitting, spin-orbit coupling, and electron-electron interactions are all present, and the combine to produce a Jeff = 1/2 ground state. In the bilayer member of this series, Sr3Ir2O7, this state manifests as electrically insulating, with unpaired Ir4+ spins aligned along the long axis of the unit cell to produce a G-type antiferromagnet with an ordered moment of 0.36 uB. In this work, this Mott state is destabilized by electron doping via La3+ substitution on the Sr-site to produce (Sr1-x Lax)3Ir2O7. The introduction of carriers initially causes nano-scale phase-separated regions to develop before driving a global insulator-to-metal transition at x=0.04. Coinciding with this transition is the disappearance of evidence of magnetic order in the system in either bulk magnetization or magnetic scattering experiments. The doping also enhances a structural order parameter observed in the parent compound at forbidden reciprocal lattice vectors. A more complete structural solution is proposed to account for this previously unresolved distortion, and also offers an explanation as to the anomalous net ferromagnetism seen prior in bulk measurements. Finally, spin dynamics are probed via a resonant x-ray technique to reveal evidence of spin-dimer-like behavior dominated by inter-plane interactions. This result supports a bond-operator treatment of the interaction Hamiltonian, and also explains the doping dependence of high temperature magnetic susceptibility.

  19. SH2-B promotes insulin receptor substrate 1 (IRS1)- and IRS2-mediated activation of the phosphatidylinositol 3-kinase pathway in response to leptin.

    Science.gov (United States)

    Duan, Chaojun; Li, Minghua; Rui, Liangyou

    2004-10-15

    Leptin regulates energy homeostasis primarily by binding and activating its long form receptor (LRb). Deficiency of either leptin or LRb causes morbid obesity. Leptin stimulates LRb-associated JAK2, thus initiating multiple pathways including the Stat3 and phosphatidylinositol (PI) 3-kinase pathways that mediate leptin biological actions. Here we report that SH2-B, a JAK2-interacting protein, promotes activation of the PI 3-kinase pathway by recruiting insulin receptor substrate 1 (IRS1) and IRS2 in response to leptin. SH2-B directly bound, via its PH and SH2 domain, to both IRS1 and IRS2 both in vitro and in intact cells and mediated formation of a JAK2/SH2-B/IRS1 or IRS2 tertiary complex. Consequently, SH2-B dramatically enhanced leptin-stimulated tyrosine phosphorylation of IRS1 and IRS2 in HEK293 cells stably expressing LRb, thus promoting association of IRS1 and IRS2 with the p85 regulatory subunit of PI 3-kinase and phosphorylation and activation of Akt. SH2-B mutants with lower affinity for IRS1 and IRS2 exhibited reduced ability to promote association of JAK2 with IRS1, tyrosine phosphorylation of IRS1, and association of IRS1 with p85 in response to leptin. Moreover, deletion of the SH2-B gene impaired leptin-stimulated tyrosine phosphorylation of endogenous IRS1 in mouse embryonic fibroblasts (MEF), which was reversed by reintroduction of SH2-B. Similarly, SH2-B promoted growth hormone-stimulated tyrosine phosphorylation of IRS1 in both HEK293 and MEF cells. Our data suggest that SH2-B is a novel mediator of the PI 3-kinase pathway in response to leptin or other hormones and cytokines that activate JAK2.

  20. A novel frequency analysis method for assessing K(ir)2.1 and Na (v)1.5 currents.

    Science.gov (United States)

    Rigby, J R; Poelzing, S

    2012-04-01

    Voltage clamping is an important tool for measuring individual currents from an electrically active cell. However, it is difficult to isolate individual currents without pharmacological or voltage inhibition. Herein, we present a technique that involves inserting a noise function into a standard voltage step protocol, which allows one to characterize the unique frequency response of an ion channel at different step potentials. Specifically, we compute the fast Fourier transform for a family of current traces at different step potentials for the inward rectifying potassium channel, K(ir)2.1, and the channel encoding the cardiac fast sodium current, Na(v)1.5. Each individual frequency magnitude, as a function of voltage step, is correlated to the peak current produced by each channel. The correlation coefficient vs. frequency relationship reveals that these two channels are associated with some unique frequencies with high absolute correlation. The individual IV relationship can then be recreated using only the unique frequencies with magnitudes of high absolute correlation. Thus, this study demonstrates that ion channels may exhibit unique frequency responses.

  1. Impurity quadrupole Kondo ground state in a dilute Pr system Y1-xPrxIr2Zn20

    Science.gov (United States)

    Yamane, Yu; Onimaru, Takahiro; Uenishi, Kazuto; Wakiya, Kazuhei; Matsumoto, Keisuke T.; Umeo, Kazunori; Takabatake, Toshiro

    2018-05-01

    The electrical resistivity ρ and specific heat C of a dilute Pr system Y1-xPrxIr2Zn20 for 0 ≤ x ≤ 0.44 were measured to study the phenomena arising from active quadrupoles of the Pr3+ ion with 4f2 configuration. On cooling, ρ's of all samples monotonically decrease, while the residual resistivity ratio ρ(300 K)/ρ(3 K) drastically decreases with x. In the whole range x ≤ 0.44, the magnetic contribution to the specific heat divided by temperature Cm/T shows a broad maximum at around 10 K, which can be reproduced by a two-level model with a first-excited triplet separated by 30 K from a ground state doublet. This indicates that the crystalline electric field ground state of the Pr ions remains in the Γ3 doublet for the cubic Td point group. On cooling, the Cm/T data for x = 0.085 and 0.44 approach constant values at Texpected from the random two-level model. By contrast, Cm/T for x = 0.044 increases continuously down to 0.08 K, suggesting a non-Fermi liquid state due to the impurity quadrupole Kondo effect.

  2. A high resolution photoemission study of surface core-level shifts in clean and oxygen-covered Ir(2 1 0) surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Gladys, M.J.; Ermanoski, I.; Jackson, G.; Quinton, J.S.; Rowe, J.E.; Madey, T.E. E-mail: madey@physics.rutgers.edu

    2004-04-01

    High resolution soft X-ray photoemission electron spectroscopy (SXPS), using synchrotron radiation, is employed to investigate 4f core-level features of four differently-prepared Ir(2 1 0) surfaces: clean planar, oxygen-covered planar, oxygen-induced faceted, and clean faceted surfaces. Surface and bulk peak identifications are supported by measurements at different photon energies (thus probing different electron escape depths) and variable emission angles. Iridium 4f{sub 7/2} photoemission spectra are fitted with Doniach-Sunjic lineshapes. The surface components are identified with core levels positioned at lower binding energies than the bulk components, in contrast to previous reports of binding energy inversion on Ir(1 0 0) (1x1) and (5x1) surfaces. For clean planar Ir(2 1 0) three surface Ir 4f{sub 7/2} features are observed with core-level shifts of -765, -529, and -281 meV, with respect to the bulk; these are associated with the first, second and third layers of atoms, respectively, for atomically rough Ir(2 1 0). Adsorption of oxygen onto the planar Ir(2 1 0) surface is found to cause a suppression and shift of the surface features to higher binding energies. Annealing at T{>=}600 K in oxygen produces a faceted surface as verified by low energy electron diffraction (LEED). A comparison of planar and faceted oxygen-covered surfaces reveals minor differences in the normal emission SXPS spectra, while grazing emission spectra exhibit differences. The SXPS spectrum of the clean, faceted Ir(2 1 0) exhibits small differences in comparison to the clean planar case, with surface features having binding energy shifts of -710, -450, and -230 meV.

  3. Up-regulation of K{sub ir}2.1 by ER stress facilitates cell death of brain capillary endothelial cells

    Energy Technology Data Exchange (ETDEWEB)

    Kito, Hiroaki [Department of Molecular and Cellular Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya (Japan); Yamazaki, Daiju [Department of Molecular and Cellular Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya (Japan); Department of Biological Chemistry, Kyoto University, Graduate School of Pharmaceutical Sciences, Kyoto (Japan); Department of Molecular Neurobiology, Graduate School of Medical Sciences, Nagoya City University, Nagoya (Japan); Ohya, Susumu; Yamamura, Hisao [Department of Molecular and Cellular Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya (Japan); Asai, Kiyofumi [Department of Molecular Neurobiology, Graduate School of Medical Sciences, Nagoya City University, Nagoya (Japan); Imaizumi, Yuji, E-mail: yimaizum@phar.nagoya-cu.ac.jp [Department of Molecular and Cellular Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya (Japan)

    2011-07-29

    Highlights: {yields} We found that application of endoplasmic reticulum (ER) stress with tunicamycin to brain capillary endothelial cells (BCECs) induced cell death. {yields} The ER stress facilitated the expression of inward rectifier K{sup +} channel (K{sub ir}2.1) and induced sustained membrane hyperpolarization. {yields} The membrane hyperpolarization induced sustained Ca{sup 2+} entry through voltage-independent nonspecific cation channels and consequently facilitated cell death. {yields} The K{sub ir}2.1 up-regulation by ER stress is, at least in part, responsible for cell death of BCECs under pathological conditions. -- Abstract: Brain capillary endothelial cells (BCECs) form blood brain barrier (BBB) to maintain brain homeostasis. Cell turnover of BCECs by the balance of cell proliferation and cell death is critical for maintaining the integrity of BBB. Here we found that stimuli with tunicamycin, endoplasmic reticulum (ER) stress inducer, up-regulated inward rectifier K{sup +} channel (K{sub ir}2.1) and facilitated cell death in t-BBEC117, a cell line derived from bovine BCECs. The activation of K{sub ir} channels contributed to the establishment of deeply negative resting membrane potential in t-BBEC117. The deep resting membrane potential increased the resting intracellular Ca{sup 2+} concentration due to Ca{sup 2+} influx through non-selective cation channels and thereby partly but significantly regulated cell death in t-BBEC117. The present results suggest that the up-regulation of K{sub ir}2.1 is, at least in part, responsible for cell death/cell turnover of BCECs induced by a variety of cellular stresses, particularly ER stress, under pathological conditions.

  4. Calculation of the band structure of GdCo2, GdRh2 e GdIr2 by the APW method

    International Nuclear Information System (INIS)

    Carvalho, J.A.B. de.

    1974-03-01

    The band structure of GdCo 2 , GdRh 2 , GdIr 2 has been calculated by the APW method. A histogram of the density of states is presented for each compound. The bands are transition-metal-like, with s-d hybridization near the Fermi level. The 5d character near the Fermi level increases as one goes from Co to Ir

  5. Recurrent Amplification at 13q34 Targets at CUL4A, IRS2, and TFDP1 As an Independent Adverse Prognosticator in Intrahepatic Cholangiocarcinoma.

    Directory of Open Access Journals (Sweden)

    Ting-Ting Liu

    Full Text Available Amplification of genes at 13q34 has been reported to be associated with tumor proliferation and progression in diverse types of cancers. However, its role in intrahepatic cholangiocarcinoma (iCCA has yet to be explored. We examined two iCCA cell lines and 86 cases of intrahepatic cholangiocarcinoma to analyze copy number of three target genes, including cullin 4A (CUL4A, insulin receptor substrate 2 (IRS2, and transcription factor Dp-1 (TFDP1 at 13q34 by quantitative real-time polymerase chain reaction. The cell lines and all tumor samples were used to test the relationship between copy number (CN alterations and protein expression by western blotting and immunohistochemical assays, respectively. IRS2 was introduced, and each target gene was silenced in cell lines. The mobility potential of cells was compared in the basal condition and after manipulation using cell migration and invasion assays. CN alterations correlated with protein expression levels. The SNU1079 cell line containing deletions of the target genes demonstrated decreased protein expression levels and significantly lower numbers of migratory and invasive cells, as opposed to the RBE cell line, which does not contain CN alterations. Overexpression of IRS2 by introducing IRS2 in SUN1079 cells increased the mobility potential. In contrast, silencing each target gene showed a trend or statistical significance toward inhibition of migratory and invasive capacities in RBE cells. In tumor samples, the amplification of each of these genes was associated with poor disease-free survival. Twelve cases (13.9% demonstrated copy numbers > 4 for all three genes tested (CUL4A, IRS2, and TFDP1, and showed a significant difference in disease-free survival by both univariate and multivariate survival analyses (hazard ratio, 2.69; 95% confidence interval, 1.23 to 5.88; P = 0.013. Our data demonstrate that amplification of genes at 13q34 plays an oncogenic role in iCCA featuring adverse disease

  6. A-site ordered perovskite CaCu3Cu2Ir2O12−δ with square-planar and octahedral coordinated Cu ions

    International Nuclear Information System (INIS)

    Zhao Qing; Wang Qing-Tao; Yin Yun-Yu; Dai Jian-Hong; Shen Xi; Yang Jun-Ye; Yu Ri-Cheng; Long You-Wen; Hu Zhi-Wei; Li Xiao-Dong

    2016-01-01

    A novel CaCu 3 Cu 2 Ir 2 O 12−δ polycrystalline sample was synthesized at 8 GPa and 1373 K. Rietveld structural analysis shows that this compound crystallizes in an -type A-site ordered perovskite structure with space group Im-3. X-ray absorption spectra reveal a +2-charge state for both the square-planar and octahedral coordinated Cu ions, and the valence state of Ir is found to be about +5. Although the A-site Ca and the A′-site Cu 2+ are 1:3 ordered at fixed atomic positions, the distribution of B-site Cu 2+ and Ir 5+ is disorderly. As a result, no long-range magnetic ordering is observed at temperatures down to 2 K. Electrical transport and heat capacity measurements demonstrate itinerant electronic behavior. The crystal structure is stable with pressure up to 35.7 GPa at room temperature. (paper)

  7. Two-Magnon Raman Scattering and Pseudospin-Lattice Interactions in Sr_{2}IrO_{4} and Sr_{3}Ir_{2}O_{7}.

    Science.gov (United States)

    Gretarsson, H; Sung, N H; Höppner, M; Kim, B J; Keimer, B; Le Tacon, M

    2016-04-01

    We have used Raman scattering to investigate the magnetic excitations and lattice dynamics in the prototypical spin-orbit Mott insulators Sr_{2}IrO_{4} and Sr_{3}Ir_{2}O_{7}. Both compounds exhibit pronounced two-magnon Raman scattering features with different energies, line shapes, and temperature dependencies, which in part reflect the different influence of long-range frustrating exchange interactions. Additionally, we find strong Fano asymmetries in the line shapes of low-energy phonon modes in both compounds, which disappear upon cooling below the antiferromagnetic ordering temperatures. These unusual phonon anomalies indicate that the spin-orbit coupling in Mott-insulating iridates is not sufficiently strong to quench the orbital dynamics in the paramagnetic state.

  8. 4PS/insulin receptor substrate (IRS)-2 is the alternative substrate of the insulin receptor in IRS-1-deficient mice.

    Science.gov (United States)

    Patti, M E; Sun, X J; Bruening, J C; Araki, E; Lipes, M A; White, M F; Kahn, C R

    1995-10-20

    Insulin receptor substrate-1 (IRS-1) is the major cytoplasmic substrate of the insulin and insulin-like growth factor (IGF)-1 receptors. Transgenic mice lacking IRS-1 are resistant to insulin and IGF-1, but exhibit significant residual insulin action which corresponds to the presence of an alternative high molecular weight substrate in liver and muscle. Recently, Sun et al. (Sun, X.-J., Wang, L.-M., Zhang, Y., Yenush, L. P., Myers, M. G., Jr., Glasheen, E., Lane, W.S., Pierce, J. H., and White, M. F. (1995) Nature 377, 173-177) purified and cloned 4PS, the major substrate of the IL-4 receptor-associated tyrosine kinase in myeloid cells, which has significant structural similarity to IRS-1. To determine if 4PS is the alternative substrate of the insulin receptor in IRS-1-deficient mice, we performed immunoprecipitation, immunoblotting, and phosphatidylinositol (PI) 3-kinase assays using specific antibodies to 4PS. Following insulin stimulation, 4PS is rapidly phosphorylated in liver and muscle, binds to the p85 subunit of PI 3-kinase, and activates the enzyme. Insulin stimulation also results in the association of 4PS with Grb 2 in both liver and muscle. In IRS-1-deficient mice, both the phosphorylation of 4PS and associated PI 3-kinase activity are enhanced, without an increase in protein expression. Immunodepletion of 4PS from liver and muscle homogenates removes most of the phosphotyrosine-associated PI 3-kinase activity in IRS-1-deficient mice. Thus, 4PS is the primary alternative substrate, i.e. IRS-2, which plays a major role in physiologic insulin signal transduction via both PI 3-kinase activation and Grb 2/Sos association. In IRS-1-deficient mice, 4PS/IRS-2 provides signal transduction to these two major pathways of insulin signaling.

  9. AMA Conferences 2015. SENSOR 2015. 17th international conference on sensors and measurement technology. IRS2 2015. 14th international conference on infrared sensors and systems. Proceedings

    International Nuclear Information System (INIS)

    2015-01-01

    This meeting paper contains presentations of two conferences: SENSOR 2015 and IRS 2 (= International conference on InfraRed Sensors and systems). The first part of SENSOR 2015 contains the following chapters: (A) SENSOR PRINCIPLES: A.1: Mechanical sensors; A.2: Optical sensors; A.3: Ultrasonic sensors; A.4: Microacoustic sensors; A.5: Magnetic sensors; A.6: Impedance sensors; A.7: Gas sensors; A.8: Flow sensors; A.9: Dimensional measurement; A.10: Temperature and humidity sensors; A.11: Chemosensors; A.12: Biosensors; A.13: Embedded sensors; A.14: Sensor-actuator systems; (B) SENSOR TECHNOLOGY: B.1: Sensor design; B.2: Numerical simulation of sensors; B.3: Sensor materials; B.4: MEMS technology; B.5: Micro-Nano-Integration; B.6: Packaging; B.7: Materials; B.8: Thin films; B.9: Sensor production; B.10: Sensor reliability; B.11: Calibration and testing; B.12: Optical fibre sensors. (C) SENSOR ELECTRONICS AND COMMUNICATION: C.1: Sensor electronics; C.2: Sensor networks; C.3: Wireless sensors; C.4: Sensor communication; C.5: Energy harvesting; C.6: Measuring systems; C.7: Embedded systems; C.8: Self-monitoring and diagnosis; (D) APPLICATIONS: D.1: Medical measuring technology; D.2: Ambient assisted living; D.3: Process measuring technology; D.4: Automotive; D.5: Sensors in energy technology; D.6: Production technology; D.7: Security technology; D.8: Smart home; D.9: Household technology. The second part with the contributions of the IRS 2 2015 is structured as follows: (E) INFRARED SENSORS: E.1: Photon detectors; E.2: Thermal detectors; E.3: Cooled detectors; E.4: Uncooled detectors; E.5: Sensor modules; E.6: Sensor packaging. (G) INFRARED SYSTEMS AND APPLICATIONS: G.1: Thermal imaging; G.2: Pyrometry / contactless temperature measurement; G.3: Gas analysis; G.4: Spectroscopy; G.5: Motion control and presence detection; G.6: Security and safety monitoring; G.7: Non-destructive testing; F: INFRARED SYSTEM COMPONENTS: F.1: Infrared optics; F.2: Optical modulators; F.3

  10. Theory of a quantum spin liquid in the hydrogen-intercalated honeycomb iridate H3LiIr2O6

    Science.gov (United States)

    Slagle, Kevin; Choi, Wonjune; Chern, Li Ern; Kim, Yong Baek

    2018-03-01

    We propose a theoretical model for a gapless spin liquid phase that may have been observed in a recent experiment on H3LiIr2O6 . Despite the insulating and nonmagnetic nature of the material, the specific heat coefficient C /T ˜1 /√{T } in zero magnetic field and C /T ˜T /B3 /2 with finite magnetic field B have been observed. In addition, the NMR relaxation rate shows 1 /(T1T ) ˜(C/T ) 2 . Motivated by the fact that the interlayer/in-plane lattice parameters are reduced/elongated by the hydrogen intercalation of the parent compound Li2IrO3 , we consider four layers of the Kitaev honeycomb lattice model with additional interlayer exchange interactions. It is shown that the resulting spin liquid excitations reside mostly in the top and bottom layers of such a layered structure and possess a quartic dispersion. In an applied magnetic field, each quartic mode is split into four Majorana cones with the velocity v ˜B3 /4 . We suggest that the spin liquid phase in these "defect" layers, placed between different stacking patterns of the honeycomb layers, can explain the major phenomenology of the experiment, which can be taken as evidence that the Kitaev interaction plays the primary role in the formation of a quantum spin liquid in this material.

  11. Bond Shortening (1.4 Å) in the Singlet and Triplet Excited States of [Ir2(dimen)4]2+ in Solution Determined by Time-Resolved X-ray Scattering

    DEFF Research Database (Denmark)

    Haldrup, Martin Kristoffer; Harlang, Tobias; Christensen, Morten

    2011-01-01

    Ground- and excited-state structures of the bimetallic, ligand-bridged compound Ir2(dimen)42+ are investigated in acetonitrile by means of time-resolved X-ray scattering. Following excitation by 2 ps laser pulses at 390 nm, analysis of difference scattering patterns obtained at eight different ti...

  12. Genetic variation in candidate obesity genes ADRB2, ADRB3, GHRL, HSD11B1, IRS1, IRS2, and SHC1 and risk for breast cancer in the Cancer Prevention Study II.

    Science.gov (United States)

    Feigelson, Heather Spencer; Teras, Lauren R; Diver, W Ryan; Tang, Weining; Patel, Alpa V; Stevens, Victoria L; Calle, Eugenia E; Thun, Michael J; Bouzyk, Mark

    2008-01-01

    Obesity has consistently been associated with postmenopausal breast cancer risk. Proteins that are secreted by adipose tissue or are involved in regulating body mass may play a role in breast tumor development. We conducted a nested case-control study among postmenopausal women from the American Cancer Society Cancer Prevention Study II Nutrition Cohort to determine whether genes associated with obesity increase risk for breast cancer. Tagging single nucleotide polymorphisms (SNPs) were selected to capture common variation across seven candidate genes that encode adipose-related proteins: ADRB2, ADRB3, GHRL, HSD11B1, IRS1, IRS2, and SHC1. Thirty-nine SNPs were genotyped in 648 cases and 659 controls. Logistic regression models were used to examine the association between each tagging SNP and risk for breast cancer while adjusting for matching factors and potential confounders. We also examined whether these SNPs were associated with measures of adult adiposity. Two out of five tagging SNPs in HSD11B1 were associated with breast cancer (rs11807619, P = 0.006; rs932335, P = 0.0001). rs11807619 and rs932335 were highly correlated (r2 = 0.74) and, when modeled as a haplotype, only haplotypes containing the rs932335 C allele were associated with breast cancer. The rs932335 C allele was associated with a nearly twofold increased risk for breast cancer (odds ratio = 1.83, 95% confidence interval = 1.01-3.33 for C/C versus G/G). Three of the 11 SNPs for IRS2 were associated with breast cancer (rs4773082, P = 0.007; rs2289046, P = 0.016; rs754204, P = 0.03). When these three SNPs were examined as a haplotype, only the haplotype that included the G allele of rs2289046 was associated with breast cancer (odds ratio = 0.76, 95% confidence interval = 0.63-0.92 for TGC versus CAT). IRS2 rs2289046, rs754204, and rs12584136 were also associated with adult weight gain but only among cases. None of the other SNPs in any gene investigated were associated with breast cancer or

  13. PEP-II IR-2 Alignment

    International Nuclear Information System (INIS)

    Seryi, A

    2004-01-01

    This paper describes the first results and preliminary analysis obtained with several alignment monitoring systems recently installed in the PEP-II interaction region. The hydrostatic level system, stretched wire system, and laser tracker have been installed in addition to the existing tiltmeters and LVDT sensors. These systems detected motion of the left raft, which correlated primarily with the low energy ring (LER) current. The motion is of the order of 120 micrometers. The cause was identified as synchrotron radiation heating the beampipe, causing its expansion which then results in its deformation and offset of the IR quadrupoles. We also discuss further plans on measurements, analysis and means to counteract this motion

  14. Reprogramming human umbilical cord mesenchymal stromal cells to islet-like cells with the use of in vitro-synthesized pancreatic-duodenal homebox 1 messenger RNA.

    Science.gov (United States)

    Wang, Xiao Li; Hu, Pei; Guo, Xing Rong; Yan, Ding; Yuan, Yahong; Yan, Shi Rong; Li, Dong Sheng

    2014-11-01

    Human umbilical cord mesenchymal stromal cells (hUC-MSCs) hold great potential as a therapeutic candidate to treat diabetes, owing to their unlimited source and ready availability. In this study, we differentiated hUC-MSCs with in vitro-synthesized pancreatic-duodenal homebox 1 (PDX1) messenger (m)RNA into islet-like cell clusters. hUC-MSCs were confirmed by both biomarker detection and functional differentiation. In vitro-synthesized PDX1 messenger RNA can be transfected into hUC-MSCs efficiently. The upregulated expression of PDX1 protein can be detected 4 h after transfection and remains detectable for 36 h. The induction of islet-like structures was confirmed by means of morphology and dithizone staining. Reverse transcriptase-polymerase chain reaction results revealed the expression of some key pancreatic transcription factors, such as PDX1, NeuroD, NKX6.1, Glut-2 and insulin in islet-like cell clusters. Immunofluorescence analysis showed that differentiated cells express both insulin and C-peptide. Enzyme-linked immunosorbent assay analysis validated the insulin secretion of islet-like cell clusters in response to the glucose stimulation. Our results demonstrate the use of in vitro-synthesized PDX1 messenger RNA to differentiate hUC-MSCs into islet-like cells and pave the way toward the development of reprogramming and directed-differentiation methods for the expression of encoded proteins. Copyright © 2014 International Society for Cellular Therapy. Published by Elsevier Inc. All rights reserved.

  15. Influence of Flavonoids on Mechanism of Modulation of Insulin Secretion.

    Science.gov (United States)

    Soares, Juliana Mikaelly Dias; Pereira Leal, Ana Ediléia Barbosa; Silva, Juliane Cabral; Almeida, Jackson R G S; de Oliveira, Helinando Pequeno

    2017-01-01

    -dependent protein kinase II, GSIS: Glucose-stimulated insulin secretion, Insig-1: Insulin-induced gene 1, IRS-2: Insulin receptor substrate 2, PDX-1: Pancreatic and duodenal homeobox 1, SREBP-1c: Sterol regulatory element binding protein-1c, DMC: Dihydroxy-6'-methoxy-3',5'-dimethylchalcone, GLP-1: Glucagon-like peptide-1, GLP-1R: Glucagon-like peptide 1 receptor.

  16. Renin-angiotensin system blockers protect pancreatic islets against diet-induced obesity and insulin resistance in mice.

    Directory of Open Access Journals (Sweden)

    Eliete Dalla Corte Frantz

    Full Text Available BACKGROUND: The associations between obesity, hypertension and diabetes are well established, and the renin-angiotensin system (RAS may provide a link among them. The effect of RAS inhibition on type 2 diabetes is still unclear; however, RAS seems to play an important role in the regulation of the pancreas and glucose intolerance of mice fed high-fat (HF diet. METHODS: C57BL/6 mice fed a HF diet (8 weeks were treated with aliskiren (50 mg/kg/day, enalapril (30 mg/kg/day or losartan (10 mg/kg/day for 6 weeks, and the protective effects were extensively compared among groups by morphometry, stereological tools, immunostaining, Western blotting and hormonal analysis. RESULTS: All RAS inhibitors significantly attenuated the increased blood pressure in mice fed a HF diet. Treatment with enalapril, but not aliskiren or losartan, significantly attenuated body mass (BM gain, glucose intolerance and insulin resistance, improved the alpha and beta cell mass and prevented the reduction of plasma adiponectin. Furthermore, enalapril treatment improved the protein expression of the pancreatic islet Pdx1, GLUT2, ACE2 and Mas receptors. Losartan treatment showed the greatest AT2R expression. CONCLUSION: Our findings indicate that ACE inhibition with enalapril attenuated several of the deleterious effects of the HF diet. In summary, enalapril appears to be responsible for the normalization of islet morphology and function, of alpha and beta cell mass and of Pdx1 and GLUT2 expression. These protective effects of enalapril were attributed, primarily, to the reduction in body mass gain and food intake and the enhancement of the ACE2/Ang (1-7 /Mas receptor axis and adiponectin levels.

  17. Effect of chronic intermittent hypoxia on glycometabolism in rat’ liver and the mechanism thereof

    Directory of Open Access Journals (Sweden)

    Wei YU

    2018-03-01

    Full Text Available Objective To investigate the effects of chronic intermittent hypoxia on the adipose factor and the expressions of insulin receptor substrate 2 (IRS-2, glucose transporter 2 (GLUT-2 and leptin in rat liver. Methods Twenty-four mature SD rats were randomly divided into 3 groups: control group (UC, chronic intermittent hypoxia group (CIH and reoxygenation group (RH. The arterial blood gas analysis was performed after the establishment of rat model. The serum fasting blood glucose (FBG and fasting insulin (FINS in each group were detected by peroxidase method; the concentrations of free fatty acids (FFA and leptin were detected by ELISA. The expressions of mRNA and protein of GLUT-2, IRS-2 and leptin were detected by qRT-PCR and Western blotting. Results The serous concentrations of FBG, FINS, FFA and leptin were significantly higher in CIH group than in UC group (P<0.05, and were dramatically higher in RH group than in both CIH group (P=0.003 and UC group (P=0.000. Western blotting and qRT-PCR detection showed that the protein and mRNA expressions of GLUT-2 and IRS-2 were significantly lower in CIH group than in RH group of rat liver (P<0.05, while were markedly lower in RH group than in UC group (P<0.05; the expressions of leptin protein and mRNA were significantly higher in CIH group than in RH group (P<0.05, while were obviously higher in RH group than in UC group of rat liver (P<0.05. Conclusion Insulin resistance induced by chronic intermittent hypoxia may be associated with the elevation of serum FFA and leptin, and be related to the decreased expression of GLUT-2 and IRS-2 and increased expression of leptin in liver. DOI: 10.11855/j.issn.0577-7402.2018.03.05

  18. Consequences of a Deficit in Vitamin B6 Biosynthesis de Novo for Hormone Homeostasis and Root Development in Arabidopsis1[OPEN

    Science.gov (United States)

    Boycheva, Svetlana; Dominguez, Ana; Rolcik, Jakub; Boller, Thomas; Fitzpatrick, Teresa B.

    2015-01-01

    Vitamin B6 (pyridoxal 5′-phosphate) is an essential cofactor of many metabolic enzymes. Plants biosynthesize the vitamin de novo employing two enzymes, pyridoxine synthase1 (PDX1) and PDX2. In Arabidopsis (Arabidopsis thaliana), there are two catalytically active paralogs of PDX1 (PDX1.1 and PDX1.3) producing the vitamin at comparable rates. Since single mutants are viable but the pdx1.1 pdx1.3 double mutant is lethal, the corresponding enzymes seem redundant. However, the single mutants exhibit substantial phenotypic differences, particularly at the level of root development, with pdx1.3 being more impaired than pdx1.1. Here, we investigate the differential regulation of PDX1.1 and PDX1.3 by identifying factors involved in their disparate phenotypes. Swapped-promoter experiments clarify the presence of distinct regulatory elements in the upstream regions of both genes. Exogenous sucrose (Suc) triggers impaired ethylene production in both mutants but is more severe in pdx1.3 than in pdx1.1. Interestingly, Suc specifically represses PDX1.1 expression, accounting for the stronger vitamin B6 deficit in pdx1.3 compared with pdx1.1. Surprisingly, Suc enhances auxin levels in pdx1.1, whereas the levels are diminished in pdx1.3. In the case of pdx1.3, the previously reported reduced meristem activity combined with the impaired ethylene and auxin levels manifest the specific root developmental defects. Moreover, it is the deficit in ethylene production and/or signaling that triggers this outcome. On the other hand, we hypothesize that it is the increased auxin content of pdx1.1 that is responsible for the root developmental defects observed therein. We conclude that PDX1.1 and PDX1.3 play partially nonredundant roles and are differentially regulated as manifested in disparate root growth impairment morphologies. PMID:25475669

  19. Pancreas-Specific Sirt1-Deficiency in Mice Compromises Beta-Cell Function without Development of Hyperglycemia.

    Science.gov (United States)

    Pinho, Andreia V; Bensellam, Mohammed; Wauters, Elke; Rees, Maxine; Giry-Laterriere, Marc; Mawson, Amanda; Ly, Le Quan; Biankin, Andrew V; Wu, Jianmin; Laybutt, D Ross; Rooman, Ilse

    2015-01-01

    Sirtuin 1 (Sirt1) has been reported to be a critical positive regulator of glucose-stimulated insulin secretion in pancreatic beta-cells. The effects on islet cells and blood glucose levels when Sirt1 is deleted specifically in the pancreas are still unclear. This study examined islet glucose responsiveness, blood glucose levels, pancreatic islet histology and gene expression in Pdx1Cre; Sirt1ex4F/F mice that have loss of function and loss of expression of Sirt1 specifically in the pancreas. We found that in the Pdx1Cre; Sirt1ex4F/F mice, the relative insulin positive area and the islet size distribution were unchanged. However, beta-cells were functionally impaired, presenting with lower glucose-stimulated insulin secretion. This defect was not due to a reduced expression of insulin but was associated with a decreased expression of the glucose transporter Slc2a2/Glut2 and of the Glucagon like peptide-1 receptor (Glp1r) as well as a marked down regulation of endoplasmic reticulum (ER) chaperones that participate in the Unfolded Protein Response (UPR) pathway. Counter intuitively, the Sirt1-deficient mice did not develop hyperglycemia. Pancreatic polypeptide (PP) cells were the only other islet cells affected, with reduced numbers in the Sirt1-deficient pancreas. This study provides new mechanistic insights showing that beta-cell function in Sirt1-deficient pancreas is affected due to altered glucose sensing and deregulation of the UPR pathway. Interestingly, we uncovered a context in which impaired beta-cell function is not accompanied by increased glycemia. This points to a unique compensatory mechanism. Given the reduction in PP, investigation of its role in the control of blood glucose is warranted.

  20. Pancreas-Specific Sirt1-Deficiency in Mice Compromises Beta-Cell Function without Development of Hyperglycemia.

    Directory of Open Access Journals (Sweden)

    Andreia V Pinho

    Full Text Available Sirtuin 1 (Sirt1 has been reported to be a critical positive regulator of glucose-stimulated insulin secretion in pancreatic beta-cells. The effects on islet cells and blood glucose levels when Sirt1 is deleted specifically in the pancreas are still unclear.This study examined islet glucose responsiveness, blood glucose levels, pancreatic islet histology and gene expression in Pdx1Cre; Sirt1ex4F/F mice that have loss of function and loss of expression of Sirt1 specifically in the pancreas.We found that in the Pdx1Cre; Sirt1ex4F/F mice, the relative insulin positive area and the islet size distribution were unchanged. However, beta-cells were functionally impaired, presenting with lower glucose-stimulated insulin secretion. This defect was not due to a reduced expression of insulin but was associated with a decreased expression of the glucose transporter Slc2a2/Glut2 and of the Glucagon like peptide-1 receptor (Glp1r as well as a marked down regulation of endoplasmic reticulum (ER chaperones that participate in the Unfolded Protein Response (UPR pathway. Counter intuitively, the Sirt1-deficient mice did not develop hyperglycemia. Pancreatic polypeptide (PP cells were the only other islet cells affected, with reduced numbers in the Sirt1-deficient pancreas.This study provides new mechanistic insights showing that beta-cell function in Sirt1-deficient pancreas is affected due to altered glucose sensing and deregulation of the UPR pathway. Interestingly, we uncovered a context in which impaired beta-cell function is not accompanied by increased glycemia. This points to a unique compensatory mechanism. Given the reduction in PP, investigation of its role in the control of blood glucose is warranted.

  1. Single-nucleotide polymorphism of INS, INSR, IRS1, IRS2, PPAR-G ...

    Indian Academy of Sciences (India)

    MAHESWARI

    2Department of Obstetrics and Gynecology, Sri Ramachandra Medical Centre, Chennai 600 116, India. Abstract ... dependent and is expressed at mRNA and protein levels by ..... 2004). A meta-analysis reported lower insulin levels in.

  2. Single-nucleotide polymorphism of INS, INSR, IRS1, IRS2, PPAR-G ...

    Indian Academy of Sciences (India)

    2017-03-02

    Mar 2, 2017 ... fold increase in mean value was observed in PCOS women. (9.12). However ..... racy of the model was estimated by 10-fold cross-validation. The best ..... Hara K., Okada T. and Tobe K. 2000 The Pro12Ala polymor- phism in ...

  3. Ultrafast Wiggling and Jiggling: Ir2(1,8-diisocyanomenthane)4 2+

    Czech Academy of Sciences Publication Activity Database

    Pižl, Martin; Hunter, B. M.; Greetham, G. M.; Towrie, M.; Záliš, Stanislav; Gray, H. B.; Vlček, Antonín

    2017-01-01

    Roč. 121, č. 48 (2017), s. 9275-9283 ISSN 1089-5639 R&D Projects: GA ČR GA17-01137S; GA MŠk(CZ) LTC17052 Institutional support: RVO:61388955 Keywords : Coherent oscillations * Inter-system crossings * Optical spectroscopic Subject RIV: CF - Physical ; Theoretical Chemistry OBOR OECD: Physical chemistry Impact factor: 2.847, year: 2016

  4. Homeostatic Model Assessment-Insulin Resistance (HOMA-IR 2) in Mild Subclinical Hypothyroid Subjects.

    Science.gov (United States)

    Sengupta, Shreejita; Jaseem, T; Ambalavanan, Jayachidambaram; Hegde, Anupama

    2018-04-01

    Despite various studies with conflicting results, the effect of thyroid hormones on lipids and insulin levels in dysthyroidism is of great interest. This case control study was aimed to perceive the existence of IR and dyslipidemia in mild subclinical hypothyroid subjects (TSH ≤ 9.9 µIU/ml) as compared to their age and gender matched euthyroid controls. Basic demographic information like height, weight was recorded. Serum samples of all the subjects were assayed for thyroid profile, lipid profile, blood glucose, HbA1C and insulin. BMI and insulin resistance was calculated. Compared to controls patients with mild subclinical hypothyroidism demonstrated hyperinsulinemia and dyslipidemia observed by the higher LDL cholesterol. A significantly positive correlation was observed for HOMA-IR with TSH and LDL cholesterol. Hence, even in the mild subclinical hypothyroid state assessment of thyroid function should be combined with estimation of plasma glucose, insulin and serum lipids to monitor and prevent its associated effects.

  5. Crystallization and diffraction analysis of the serpin IRS-2 from the hard tick Ixodes ricinus

    Czech Academy of Sciences Publication Activity Database

    Kovářová, Zuzana; Chmelař, Jindřich; Šanda, Miloslav; Brynda, Jiří; Mareš, Michael; Řezáčová, Pavlína

    F66, č. 11 (2010), s. 1453-1457 ISSN 1744-3091 R&D Projects: GA ČR(CZ) GAP207/10/2183; GA MŠk(CZ) LC06009 Institutional research plan: CEZ:AV0Z40550506; CEZ:AV0Z60220518; CEZ:AV0Z50520514 Keywords : protease inhibitor * serpin * tick * proteolysis Subject RIV: CE - Biochemistry Impact factor: 0.563, year: 2010

  6. Arachidonic acid and lipoxin A4 attenuate alloxan-induced cytotoxicity to RIN5F cells in vitro and type 1 diabetes mellitus in vivo.

    Science.gov (United States)

    Gundala, Naveen K V; Naidu, Vegi G M; Das, Undurti N

    2017-03-01

    We studied whether polyunsaturated fatty acids (PUFAs) can protect rat insulinoma (RIN5F) cells against alloxan-induced apoptosis in vitro and type 1 diabetes mellitus (type 1 DM) in vivo and if so, mechanism of this beneficial action. In vitro study was conducted using RIN5F cells while in vivo study was performed in Wistar rats. The effect of PUFAs, cyclo-oxygenase and lipoxygenase inhibitors, various eicosanoids and PUFAs metabolites: lipoxin A4 (LXA4), resolvin D2 and protectin against alloxan-induced cytotoxicity to RIN5F cells and type 1 DM was studied. Expression of PDX1, P65 NF-kB and IKB in RIN5F cells and Nrf2, GLUT2, COX2, iNOS protein levels in the pancreatic tissue and plasma glucose, insulin and tumor necrosis factor-α and antioxidants, lipid peroxides and nitric oxide were measured. Of all, arachidonic acid (AA) was found to be the most effective against alloxan-induced cytotoxicity to RIN5F cells and preventing type 1 DM. Both cyclo-oxygenase and lipoxygenase inhibitors did not block the beneficial actions of AA in vitro and in vivo. Alloxan inhibited LXA4 production by RIN5F cells and in alloxan-induced type 1 DM Wistar rats. AA-treatment restored LXA4 levels to normal both in vitro and in vivo. LXA4 protected RIN5F cells against alloxan-induced cytotoxicity and prevented type 1 DM and restored expression of Nrf2, Glut2, COX2, and iNOS genes and abnormal antioxidants to near normal. AA seems to bring about its beneficial actions against alloxan-induced cytotoxicity and type 1 DM by enhancing the production of LXA4. © 2016 BioFactors, 43(2):251-271, 2017. © 2016 International Union of Biochemistry and Molecular Biology.

  7. Chickens from lines artificially selected for juvenile low and high body weight differ in glucose homeostasis and pancreas physiology.

    Science.gov (United States)

    Sumners, L H; Zhang, W; Zhao, X; Honaker, C F; Zhang, S; Cline, M A; Siegel, P B; Gilbert, E R

    2014-06-01

    Artificial selection of White Plymouth Rock chickens for juvenile (day 56) body weight resulted in two divergent genetic lines: hypophagic low weight (LWS) chickens and hyperphagic obese high weight (HWS) chickens, with the latter more than 10-fold heavier than the former at selection age. A study was designed to investigate glucose regulation and pancreas physiology at selection age in LWS chickens and HWS chickens. Oral glucose tolerance and insulin sensitivity tests revealed differences in threshold sensitivity to insulin and glucose clearance rate between the lines. Results from real-time PCR showed greater pancreatic mRNA expression of four glucose regulatory genes (preproinsulin, PPI; preproglucagon, PPG; glucose transporter 2, GLUT2; and pancreatic duodenal homeobox 1, Pdx1) in LWS chickens, than HWS chickens. Histological analysis of the pancreas revealed that HWS chickens have larger pancreatic islets, less pancreatic islet mass, and more pancreatic inflammation than LWS chickens, all of which presumably contribute to impaired glucose metabolism. Copyright © 2014 Elsevier Inc. All rights reserved.

  8. The functional performance of microencapsulated human pancreatic islet-derived precursor cells.

    Science.gov (United States)

    Montanucci, Pia; Pennoni, Ilaria; Pescara, Teresa; Blasi, Paolo; Bistoni, Giovanni; Basta, Giuseppe; Calafiore, Riccardo

    2011-12-01

    We have examined long-term cultured, human islet-derived stem/precursor cells (hIPC). Whole human islets (HI) were obtained by multi-enzymatic digestion of cadaveric donor pancreases, plated on tissue flasks, and allowed to adhere and expand for several in vitro passages, in order to obtain hIPC. We detected specific stem cell markers (Oct-4, Sox-2, Nanog, ABCG2, Klf-4, CD117) in both intact HI and hIPC. Moreover, hIPC while retaining the expression of Glut-2, Pdx-1, CK-19, and ICA-512, started re-expressing Ngn3, thereby indicating acquisition of a specific pancreatic islet beta cell-oriented phenotype identity. The intrinsic plasticity of hIPC was documented by their ability to differentiate into various germ layer-derived cell phenotypes (ie, osteocytic, adipocytic and neural), including endocrine cells associated with insulin secretory capacity. To render hIPC suitable for transplantation we have enveloped them within our highly purified, alginate-based microcapsules. Upon intraperitoneal graft in NOD/SCID mice we have observed that the microcapsules acted as three-dimensional niches favouring post-transplant hIPC differentiation and acquisition of beta cell-like functional competence. Copyright © 2011 Elsevier Ltd. All rights reserved.

  9. Generation of high-yield insulin producing cells from human bone marrow mesenchymal stem cells.

    Science.gov (United States)

    Jafarian, Arefeh; Taghikhani, Mohammad; Abroun, Saeid; Pourpak, Zahra; Allahverdi, Amir; Soleimani, Masoud

    2014-07-01

    Allogenic islet transplantation is a most efficient approach for treatment of diabetes mellitus. However, the scarcity of islets and long term need for an immunosuppressant limits its application. Recently, cell replacement therapies that generate of unlimited sources of β cells have been developed to overcome these limitations. In this study we have described a stage specific differentiation protocol for the generation of insulin producing islet-like clusters from human bone marrow mesenchymal stem cells (hBM-MSCs). This specific stepwise protocol induced differentiation of hMSCs into definitive endoderm, pancreatic endoderm and pancreatic endocrine cells that expressed of sox17, foxa2, pdx1, ngn3, nkx2.2, insulin, glucagon, somatostatin, pancreatic polypeptide, and glut2 transcripts respectively. In addition, immunocytochemical analysis confirmed protein expression of the above mentioned genes. Western blot analysis discriminated insulin from proinsulin in the final differentiated cells. In derived insulin producing cells (IPCs), secreted insulin and C-peptide was in a glucose dependent manner. We have developed a protocol that generates effective high-yield human IPCs from hBM-MSCs in vitro. These finding suggest that functional IPCs generated by this procedure can be used as a cell-based approach for insulin dependent diabetes mellitus.

  10. Reversibility of β-Cell-Specific Transcript Factors Expression by Long-Term Caloric Restriction in db/db Mouse

    Directory of Open Access Journals (Sweden)

    Chunjun Sheng

    2016-01-01

    Full Text Available Type 2 diabetes (T2D is characterized by β-cell dedifferentiation, but underlying mechanisms remain unclear. The purpose of the current study was to explore the mechanisms of β-cell dedifferentiation with and without long-term control of calorie intake. We used a diabetes mouse model (db/db to analyze the changes in the expression levels of β-cell-specific transcription factors (TFs and functional factors with long-term caloric restriction (CR. Our results showed that chronic euglycemia was maintained in the db/db mice with long-term CR intervention, and β-cell dedifferentiation was significantly reduced. The expression of Glut2, Pdx1, and Nkx6.1 was reversed, while MafA expression was significantly increased with long-term CR. GLP-1 pathway was reactivated with long-term CR. Our work showed that the course of β-cell dedifferentiation can intervene by long-term control of calorie intake. Key β-cell-specific TFs and functional factors play important roles in maintaining β-cell differentiation. Targeting these factors could optimize T2D therapies.

  11. Physical activity modifies the effect of SNPs in the SLC2A2 (GLUT2) and ABCC8 (SUR1) genes on the risk of developing type 2 diabetes

    DEFF Research Database (Denmark)

    Oskari Kilpeläinen, Tuomas; Lakka, T A; Laaksonen, D E

    2007-01-01

    . The interaction of the SNPs with the change in PA on the conversion to T2D was assessed using Cox regression with adjustments for the other components of the intervention (dietary changes, weight reduction). The carriers of the common homozygous genotype of rs5393, rs5394, or rs5404 of SLC2A2 and rs3758947...

  12. Consequences of a deficit in vitamin B6 biosynthesis de novo for hormone homeostasis and root development in Arabidopsis.

    Science.gov (United States)

    Boycheva, Svetlana; Dominguez, Ana; Rolcik, Jakub; Boller, Thomas; Fitzpatrick, Teresa B

    2015-01-01

    Vitamin B(6) (pyridoxal 5'-phosphate) is an essential cofactor of many metabolic enzymes. Plants biosynthesize the vitamin de novo employing two enzymes, pyridoxine synthase1 (PDX1) and PDX2. In Arabidopsis (Arabidopsis thaliana), there are two catalytically active paralogs of PDX1 (PDX1.1 and PDX1.3) producing the vitamin at comparable rates. Since single mutants are viable but the pdx1.1 pdx1.3 double mutant is lethal, the corresponding enzymes seem redundant. However, the single mutants exhibit substantial phenotypic differences, particularly at the level of root development, with pdx1.3 being more impaired than pdx1.1. Here, we investigate the differential regulation of PDX1.1 and PDX1.3 by identifying factors involved in their disparate phenotypes. Swapped-promoter experiments clarify the presence of distinct regulatory elements in the upstream regions of both genes. Exogenous sucrose (Suc) triggers impaired ethylene production in both mutants but is more severe in pdx1.3 than in pdx1.1. Interestingly, Suc specifically represses PDX1.1 expression, accounting for the stronger vitamin B6 deficit in pdx1.3 compared with pdx1.1. Surprisingly, Suc enhances auxin levels in pdx1.1, whereas the levels are diminished in pdx1.3. In the case of pdx1.3, the previously reported reduced meristem activity combined with the impaired ethylene and auxin levels manifest the specific root developmental defects. Moreover, it is the deficit in ethylene production and/or signaling that triggers this outcome. On the other hand, we hypothesize that it is the increased auxin content of pdx1.1 that is responsible for the root developmental defects observed therein. We conclude that PDX1.1 and PDX1.3 play partially nonredundant roles and are differentially regulated as manifested in disparate root growth impairment morphologies. © 2015 American Society of Plant Biologists. All Rights Reserved.

  13. Ixodes ricinus Salivary Serpin IRS-2 Affects Th17 Differentiation via Inhibition of the Interleukin-6/STAT-3 Signaling Pathway

    Czech Academy of Sciences Publication Activity Database

    Páleníková, Jana; Lieskovská, Jaroslava; Langhansová, Helena; Kotsyfakis, Michalis; Chmelař, J.; Kopecký, Jan

    2015-01-01

    Roč. 83, č. 5 (2015), s. 1949-1956 ISSN 0019-9567 R&D Projects: GA ČR GAP302/12/2208 Institutional support: RVO:60077344 Keywords : T-cells * Borrelia burgdorferi * transcription factor Subject RIV: EC - Immunology Impact factor: 3.603, year: 2015

  14. Influence and timing of arrival of murine neural crest on pancreatic beta cell development and maturation.

    Science.gov (United States)

    Plank, Jennifer L; Mundell, Nathan A; Frist, Audrey Y; LeGrone, Alison W; Kim, Thomas; Musser, Melissa A; Walter, Teagan J; Labosky, Patricia A

    2011-01-15

    Interactions between cells from the ectoderm and mesoderm influence development of the endodermally-derived pancreas. While much is known about how mesoderm regulates pancreatic development, relatively little is understood about how and when the ectodermally-derived neural crest regulates pancreatic development and specifically, beta cell maturation. A previous study demonstrated that signals from the neural crest regulate beta cell proliferation and ultimately, beta cell mass. Here, we expand on that work to describe timing of neural crest arrival at the developing pancreatic bud and extend our knowledge of the non-cell autonomous role for neural crest derivatives in the process of beta cell maturation. We demonstrated that murine neural crest entered the pancreatic mesenchyme between the 26 and 27 somite stages (approximately 10.0 dpc) and became intermingled with pancreatic progenitors as the epithelium branched into the surrounding mesenchyme. Using a neural crest-specific deletion of the Forkhead transcription factor Foxd3, we ablated neural crest cells that migrate to the pancreatic primordium. Consistent with previous data, in the absence of Foxd3, and therefore the absence of neural crest cells, proliferation of insulin-expressing cells and insulin-positive area are increased. Analysis of endocrine cell gene expression in the absence of neural crest demonstrated that, although the number of insulin-expressing cells was increased, beta cell maturation was significantly impaired. Decreased MafA and Pdx1 expression illustrated the defect in beta cell maturation; we discovered that without neural crest, there was a reduction in the percentage of insulin-positive cells that co-expressed Glut2 and Pdx1 compared to controls. In addition, transmission electron microscopy analyses revealed decreased numbers of characteristic insulin granules and the presence of abnormal granules in insulin-expressing cells from mutant embryos. Together, these data demonstrate that

  15. Arachidonic acid and lipoxinA4 attenuate streptozotocin-induced cytotoxicity to RIN5 F cells in vitro and type 1 and type 2 diabetes mellitus in vivo.

    Science.gov (United States)

    Gundala, Naveen K V; Naidu, Vegi G M; Das, Undurti N

    2017-03-01

    The aim of this study was to observe whether polyunsaturated fatty acids (PUFAs) can protect rat insulinoma (RIN5 F) cells against streptozotocin (STZ)-induced apoptosis in vitro and type 1 diabetes mellitus (T1DM) and type 2 DM (T2DM) in vivo and if so, what would be the mechanism of this action. RIN5 F cells were used for the in vitro study, whereas the in vivo study was performed in Wistar rats. STZ was used to induce apoptosis of RIN5 F cells in vitro and T1- and T2DM in vivo. The effect of PUFAs: γ-linolenic acid (GLA), arachidonic acid (AA) of ω-6 series, and eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) of ω-3 series; cyclooxygenase (COX) and lipoxygenase (LOX) inhibitors and antiinflammatory metabolite of AA and DHA, lipoxin A4 (LXA4), and resolvin D2 and protectin, respectively against STZ-induced cytotoxicity to RIN5 F cells in vitro and LXA4 against T1- and T2DM in vivo was studied. Changes in the antioxidant content, lipid peroxides, nitric oxide, and expression of PDX1, P65, nuclear factor-κb (NF-κb), and IKB genes in STZ-treated RIN5 F cells in vitro and Nrf2, GLUT2, COX2, iNOS protein levels in the pancreatic tissue of T1- and T2DM and LPCLN2 (lipocalin 2), NF-κb, IKB I in adipose tissue of T2DM after LXA4 treatment were studied. Plasma glucose, insulin, and tumor necrosis factor (TNF)-α levels also were measured in STZ-induced T1- and T2DM Wistar rats. Among all PUFAs tested, AA and EPA are the most effective against STZ-induced cytotoxicity to RIN5 F cells in vitro. Neither COX nor LOX inhibitors blocked the cytoprotective action of AA in vitro and T1- and T2DM by STZ. LXA4 production by RIN5 F cells in vitro and plasma LXA4 levels in STZ-induced T1- and T2DM animals were decreased by STZ that reverted to normal after AA treatment. AA prevented both T1- and T2DM induced by STZ. Antiinflammatory metabolite of AA and LXA4 prevented both T1- and T2DM induced by STZ. The expression of Pdx1, NF-κb, IKB genes in the

  16. High-fat diet induced insulin resistance in pregnant rats through pancreatic pax6 signaling pathway.

    Science.gov (United States)

    Wu, Hao; Liu, Yunyun; Wang, Hongkun; Xu, Xianming

    2015-01-01

    To explore the changes in pancreas islet function of pregnant rats after consumption of high-fat diet and the underlying mechanism. Thirty pregnant Wistar rats were randomly divided into two groups: high-fat diet group and normal control group. Twenty days after gestation, fasting blood glucose concentration (FBG) and fasting serum insulin concentration (FINS) were measured. Then, oral glucose tolerance test (OGTT) and insulin release test (IRT) were performed. Finally, all the rats were sacrificed and pancreas were harvested. Insulin sensitivity index (ISI) and insulin resistance index (HOMA-IR) were calculated according to FBG and FINS. RT-PCR and Real-time PCR were performed to study the expression of paired box 6 transcription factor (Pax6) and its target genes in pancreatic tissues. The body weight was significantly increased in the high-fat diet group compared with that of normal control rats (Pinsulin concentration between the two groups. OGTT and IRT were abnormal in the high-fat diet group. The high-fat diet rats were more prone to impaired glucose tolerance and insulin resistance. The level of the expression of Pax6 transcription factor and its target genes in pancreas, such as pancreatic and duodenal homeobox factor-1 (Pdx1), v-maf musculoaponeurotic fibrosarcoma oncogene homolog A (MafA) and glucose transporter 2 (Glut2) were decreased significantly compared with those of normal control group. High-fat diet feeding during pregnancy may induce insulin resistance in maternal rats by inhibiting pancreatic Pax6 and its target genes expression.

  17. miR-375 induces human decidua basalis-derived stromal cells to become insulin-producing cells.

    Science.gov (United States)

    Shaer, Anahita; Azarpira, Negar; Vahdati, Akbar; Karimi, Mohammad Hosein; Shariati, Mehrdad

    2014-09-01

    This paper focuses on the development of renewable sources of isletreplacement tissue for the treatment of type I diabetes mellitus. Placental tissue-derived mesenchymal stem cells (MSCs) are a promising source for regenerative medicine due to their plasticity and easy availability. They have the potential to differentiate into insulin-producing cells. miR-375 is a micro RNA that is expressed in the pancreas and involved in islet development. Human placental decidua basalis MSCs (PDB-MSCs) were cultured from full-term human placenta. The immunophenotype of the isolated cells was checked for CD90, CD105, CD44, CD133 and CD34 markers. The MSCs (P3) were chemically transfected with hsa-miR-375. Total RNA was extracted 4 and 6 days after transfection. The expressions of insulin, NGN3, GLUT2, PAX4, PAX6, KIR6.2, NKX6.1, PDX1, and glucagon genes were evaluated using real-time qPCR. On day 6, we tested the potency of the clusters in response to the high glucose challenge and assessed the presence of insulin and NGN3 proteins via immunocytochemistry. Flow cytometry analysis confirmed that more than 90% of the cells were positive for CD90, CD105 and CD44 and negative for CD133 and CD34. Morphological changes were followed from day 2. Cell clusters formed during day 6. Insulin-producing clusters showed a deep red color with DTZ. The expression of pancreatic-specific transcription factors increased remarkably during the four days after transfection and significantly increased on day 7. The clusters were positive for insulin and NGN3 proteins, and C-peptide and insulin secretion increased in response to changes in the glucose concentration (2.8 mM and 16.7 mM). In conclusion, the MSCs could be programmed into functional insulin-producing cells by transfection of miR-375.

  18. Differentiation of human-induced pluripotent stem cells into insulin-producing clusters.

    Science.gov (United States)

    Shaer, Anahita; Azarpira, Negar; Vahdati, Akbar; Karimi, Mohammad Hosein; Shariati, Mehrdad

    2015-02-01

    In diabetes mellitus type 1, beta cells are mostly destroyed; while in diabetes mellitus type 2, beta cells are reduced by 40% to 60%. We hope that soon, stem cells can be used in diabetes therapy via pancreatic beta cell replacement. Induced pluripotent stem cells are a kind of stem cell taken from an adult somatic cell by "stimulating" certain genes. These induced pluripotent stem cells may be a promising source of cell therapy. This study sought to produce isletlike clusters of insulin-producing cells taken from induced pluripotent stem cells. A human-induced pluripotent stem cell line was induced into isletlike clusters via a 4-step protocol, by adding insulin, transferrin, and selenium (ITS), N2, B27, fibroblast growth factor, and nicotinamide. During differentiation, expression of pancreatic β-cell genes was evaluated by reverse transcriptase-polymerase chain reaction; the morphologic changes of induced pluripotent stem cells toward isletlike clusters were observed by a light microscope. Dithizone staining was used to stain these isletlike clusters. Insulin produced by these clusters was evaluated by radio immunosorbent assay, and the secretion capacity was analyzed with a glucose challenge test. Differentiation was evaluated by analyzing the morphology, dithizone staining, real-time quantitative polymerase chain reaction, and immunocytochemistry. Gene expression of insulin, glucagon, PDX1, NGN3, PAX4, PAX6, NKX6.1, KIR6.2, and GLUT2 were documented by analyzing real-time quantitative polymerase chain reaction. Dithizone-stained cellular clusters were observed after 23 days. The isletlike clusters significantly produced insulin. The isletlike clusters could increase insulin secretion after a glucose challenge test. This work provides a model for studying the differentiation of human-induced pluripotent stem cells to insulin-producing cells.

  19. FGF-2b and h-PL Transform Duct and Non-Endocrine Human Pancreatic Cells into Endocrine Insulin Secreting Cells by Modulating Differentiating Genes

    Directory of Open Access Journals (Sweden)

    Giulia Donadel

    2017-10-01

    Full Text Available Background: Diabetes mellitus (DM is a multifactorial disease orphan of a cure. Regenerative medicine has been proposed as novel strategy for DM therapy. Human fibroblast growth factor (FGF-2b controls β-cell clusters via autocrine action, and human placental lactogen (hPL-A increases functional β-cells. We hypothesized whether FGF-2b/hPL-A treatment induces β-cell differentiation from ductal/non-endocrine precursor(s by modulating specific genes expression. Methods: Human pancreatic ductal-cells (PANC-1 and non-endocrine pancreatic cells were treated with FGF-2b plus hPL-A at 500 ng/mL. Cytofluorimetry and Immunofluorescence have been performed to detect expression of endocrine, ductal and acinar markers. Bromodeoxyuridine incorporation and annexin-V quantified cells proliferation and apoptosis. Insulin secretion was assessed by RIA kit, and electron microscopy analyzed islet-like clusters. Results: Increase in PANC-1 duct cells de-differentiation into islet-like aggregates was observed after FGF-2b/hPL-A treatment showing ultrastructure typical of islets-aggregates. These clusters, after stimulation with FGF-2b/hPL-A, had significant (p < 0.05 increase in insulin, C-peptide, pancreatic and duodenal homeobox 1 (PDX-1, Nkx2.2, Nkx6.1, somatostatin, glucagon, and glucose transporter 2 (Glut-2, compared with control cells. Markers of PANC-1 (Cytokeratin-19, MUC-1, CA19-9 were decreased (p < 0.05. These aggregates after treatment with FGF-2b/hPL-A significantly reduced levels of apoptosis. Conclusions: FGF-2b and hPL-A are promising candidates for regenerative therapy in DM by inducing de-differentiation of stem cells modulating pivotal endocrine genes.

  20. Biocheminių ir imuninių tyrimų reikšmė sergantiems 1 ir 2 tipo cukriniu diabetu

    OpenAIRE

    Tekoriūtė, Greta

    2017-01-01

    The aim of the study: To assess the significance of biochemical and immunological markers for the differential diagnosis of type 1 and 2 diabetes. The objectives of the study. 1. To identify the difference of biochemical and immunological markers among the patients affected with type 1 and type 2 diabetes. 2. To determine the interface of biochemical and immunological markers according to the age and sex of the patients affected with type 1 and type 2 diabetes. 3. To determine the frequenc...

  1. Differentiation of 5-hydroxytryptamine2 receptor subtypes using 125I-R-(-)2,5-dimethoxy-4-iodo-phenylisopropylamine and 3H-ketanserin

    International Nuclear Information System (INIS)

    McKenna, D.J.; Peroutka, S.J.

    1989-01-01

    The radioligand binding characteristics of 125I-R-(-)4-iodo-2,5-dimethoxyphenylisopropylamine [125I-R-(-)DOI] and 3H-ketanserin were compared in rat and bovine cortical membranes. In rat cortex, 125I-R-(-)DOI labels a relatively low density of binding sites (Bmax = 2.5 +/- 0.2 pmol/gm tissue) with high affinity (KD = 0.63 +/- 0.09 nM). In bovine cortex, specific binding of 125I-R-(-)DOI represents less than 20% of total binding at radioligand concentrations above 0.6 nM, and, therefore, the data cannot be analyzed adequately by Scatchard transformation. By contrast, 3H-ketanserin displays saturable, specific high-affinity binding in both rat cortex (KD = 1.0 +/- 0.1 nM; Bmax = 11 +/- 0.4 pmol/gm tissue) and bovine cortex (KD = 1.2 +/- 0.2 nM; Bmax = 5.3 +/- 0.4 pmol/gm tissue). Ki values for 30 drugs were determined for 125I-R-(-)DOI-labeled sites in rat cortex and 3H-ketanserin-labeled sites in bovine cortex. 5-Hydroxytryptamine (5-HT) displays 250-fold higher selectivity for the 125I-R-(-)DOI-labeled sites (Ki = 3.0 +/- 0.7 nM) than for the 3H-ketanserin-labeled sites (Ki = 750 +/- 50 nM). Structural congeners of R-(-)DOI display 80- to 160-fold higher affinity for the 125I-R-(-)DOI binding site than for the 3H-ketanserin-labeled binding site. d-LSD and putative 5-HT2 antagonists are approximately equipotent at both sites. Significant correlations were found between drug affinities for 125I-R-(-)DOI-labeled sites in rat cortex and putative 5-HT2A sites labeled previously by 77Br-R-(-)DOB (r = 0.93, p less than 0.01), putative 5-HT2B sites labeled by 3H-ketanserin in bovine cortex (r = 0.63, p less than 0.01), and 5-HT1C binding sites that have been characterized by other investigators (r = 0.78, p less than 0.01). No significant correlations were found between drug affinities for 125I-R-(-)DOI-labeled sites in rat cortex and 5-HT1A, 5-HT1B, 5-HT1D, or 5-HT3 sites, as determined by previous investigators

  2. Animal Model of Gestational Diabetes Mellitus with Pathophysiological Resemblance to the Human Condition Induced by Multiple Factors (Nutritional, Pharmacological, and Stress in Rats

    Directory of Open Access Journals (Sweden)

    Siti Hajar Abdul Aziz

    2016-01-01

    Full Text Available This study attempts to develop an experimental gestational diabetes mellitus (GDM animal model in female Sprague-Dawley rats. Rats were fed with high fat sucrose diet, impregnated, and induced with Streptozotocin and Nicotinamide on gestational day 0 (D0. Sleeping patterns of the rats were also manipulated to induce stress, a lifestyle factor that contributes to GDM. Rats were tested for glycemic parameters (glucose, C-peptide, and insulin, lipid profiles (total cholesterol, triglycerides, HDL, and LDL, genes affecting insulin signaling (IRS-2, AKT-1, and PCK-1, glucose transporters (GLUT-2 and GLUT-4, proinflammatory cytokines (IL-6, TNF-α, and antioxidants (SOD, CAT, and GPX on D6 and D21. GDM rats showed possible insulin resistance as evidenced by high expression of proinflammatory cytokines, PCK-1 and CRP. Furthermore, low levels of IRS-2 and AKT-1 genes and downregulation of GLUT-4 from the initial to final phases indicate possible defect of insulin signaling. GDM rats also showed an impairment of antioxidant status and a hyperlipidemic state. Additionally, GDM rats exhibited significantly higher body weight and blood glucose and lower plasma insulin level and C-peptide than control. Based on the findings outlined, the current GDM animal model closely replicates the disease state in human and can serve as a reference for future investigations.

  3. Production of a mouse strain with impaired glucose tolerance by systemic heterozygous knockout of the glucokinase gene and its feasibility as a prediabetes model

    Science.gov (United States)

    SAITO, Mikako; KANEDA, Asako; SUGIYAMA, Tae; IIDA, Ryousuke; OTOKUNI, Keiko; KABURAGI, Misako; MATSUOKA, Hideaki

    2015-01-01

    Exon II of glucokinase (Gk) was deleted to produce a systemic heterozygous Gk knockout (Gk+/−) mouse. The relative expression levels of Gk in the heart, lung, liver, stomach, and pancreas in Gk+/− mice ranged from 0.41–0.68 versus that in wild (Gk+/+) mice. On the other hand, its expression levels in the brain, adipose tissue, and muscle ranged from 0.95–1.03, and its expression levels in the spleen and kidney were nearly zero. Gk knockout caused no remarkable off-target effect on the expression of 7 diabetes causing genes (Shp, Hnf1a, Hnf1b, Irs1, Irs2, Kir6.2, and Pdx1) in 10 organs. The glucose tolerance test was conducted to determine the blood glucose concentrations just after fasting for 24 h (FBG) and at 2 h after high-glucose application (GTT2h). The FBG-GTT2h plots obtained with the wild strain fed the control diet (CD), Gk+/− strain fed the CD, and Gk+/− strain fed the HFD were distributed in separate areas in the FBG-GTT2h diagram. The respective areas could be defined as the normal state, prediabetes state, and diabetes state, respectively. Based on the results, the criteria for prediabetes could be defined for the Gk+/− strain developed in this study. PMID:25765873

  4. FoxO1 gain of function in the pancreas causes glucose intolerance, polycystic pancreas, and islet hypervascularization.

    Directory of Open Access Journals (Sweden)

    Osamu Kikuchi

    Full Text Available Genetic studies revealed that the ablation of insulin/IGF-1 signaling in the pancreas causes diabetes. FoxO1 is a downstream transcription factor of insulin/IGF-1 signaling. We previously reported that FoxO1 haploinsufficiency restored β cell mass and rescued diabetes in IRS2 knockout mice. However, it is still unclear whether FoxO1 dysregulation in the pancreas could be the cause of diabetes. To test this hypothesis, we generated transgenic mice overexpressing constitutively active FoxO1 specifically in the pancreas (TG. TG mice had impaired glucose tolerance and some of them indeed developed diabetes due to the reduction of β cell mass, which is associated with decreased Pdx1 and MafA in β cells. We also observed increased proliferation of pancreatic duct epithelial cells in TG mice and some mice developed a polycystic pancreas as they aged. Furthermore, TG mice exhibited islet hypervascularities due to increased VEGF-A expression in β cells. We found FoxO1 binds to the VEGF-A promoter and regulates VEGF-A transcription in β cells. We propose that dysregulation of FoxO1 activity in the pancreas could account for the development of diabetes and pancreatic cysts.

  5. Nuclear SREBP-1a causes loss of pancreatic β-cells and impaired insulin secretion

    International Nuclear Information System (INIS)

    Iwasaki, Yuko; Iwasaki, Hitoshi; Yatoh, Shigeru; Ishikawa, Mayumi; Kato, Toyonori; Matsuzaka, Takashi; Nakagawa, Yoshimi; Yahagi, Naoya; Kobayashi, Kazuto; Takahashi, Akimitsu; Suzuki, Hiroaki; Yamada, Nobuhiro; Shimano, Hitoshi

    2009-01-01

    Transgenic mice expressing nuclear sterol regulatory element-binding protein-1a under the control of the insulin promoter were generated to determine the role of SREBP-1a in pancreatic β-cells. Only low expressors could be established, which exhibited mild hyperglycemia, impaired glucose tolerance, and reduced plasma insulin levels compared to C57BL/6 controls. The islets isolated from the transgenic mice were fewer and smaller, and had decreased insulin content and unaltered glucagon staining. Both glucose- and potassium-stimulated insulin secretions were decreased. The transgenic islets consistently expressed genes for fatty acids and cholesterol synthesis, resulting in accumulation of triglycerides but not cholesterol. PDX-1, ΒΕΤΑ2, MafA, and IRS-2 were suppressed, partially explaining the loss and dysfunction of β-cell mass. The transgenic mice on a high fat/high sucrose diet still exhibited impaired insulin secretion and continuous β-cell growth defect. Therefore, nuclear SREBP-1a, even at a low level, strongly disrupts β-cell mass and function.

  6. Developmental biology of the Psammomys obesus pancreas

    DEFF Research Database (Denmark)

    Vedtofte, Louise; Bödvarsdóttir, Thóra B; Karlsen, Allan E

    2007-01-01

    The desert gerbil Psammomys obesus, an established model of type 2 diabetes (T2D), has previously been shown to lack pancreatic and duodenal homeobox gene 1 (Pdx-1) expression. Pdx-1 deficiency leads to pancreas agenesis in both mice and humans. We have therefore further examined the pancreas of ...

  7. Protective effects of SGLT2 inhibitor luseogliflozin on pancreatic β-cells in obese type 2 diabetic db/db mice

    Energy Technology Data Exchange (ETDEWEB)

    Okauchi, Seizo, E-mail: okauchi@med.kawasaki-m.ac.jp; Shimoda, Masashi; Obata, Atsushi; Kimura, Tomohiko; Hirukawa, Hidenori; Kohara, Kenji; Mune, Tomoatsu; Kaku, Kohei; Kaneto, Hideaki

    2016-02-12

    It is well known that Sodium-Glucose Co-transporter 2 (SGLT2) inhibitors, new hypoglycemic agents, improve glycemic control by increasing urine glucose excretion, but it remained unclear how they exert protective effects on pancreatic β-cells. In this study, we examined the effects of SGLT2 inhibitor luseogliflozin on β-cell function and mass using obese type 2 diabetic db/db mice. Ten-week-old male diabetic db/db mice were treated with luseogliflozin 0.0025% or 0.01% in chow (Luse 0.0025% or Luse 0.01%) or vehicle (control) for 4 weeks. Urinary glucose excretion was increased in Luse groups (0.0025% and 0.01%) compared to control mice 3 days after the intervention. Fasting blood glucose levels were significantly lower in mice treated with Luse compared to control mice. Fasting serum insulin concentrations were significantly higher in mice treated with Luse compared to control mice. Triglyceride levels tended to be lower in Luse groups compared to control mice. In immunohistochemical study using pancreas tissues, β-cell mass was larger in Luse groups compared to control group which was due to the increase of β-cell proliferation and decrease of β-cell apoptosis. Furthermore, in gene analysis using isolated islets, insulin 1, insulin 2, MafA, PDX-1 and GLUT2 gene expression levels were significantly higher in Luse groups compared to control group. In contrast, expression levels of fibrosis-related gene such as TGFβ, fibronectin, collagen I and collagen III were significantly lower in Luse groups. In conclusion, SGLT2 inhibitor luseogliflozin ameliorates glycemic control and thus exerts protective effects on pancreatic β-cell mass and function. - Highlights: • SGLT2 inhibitor luseogliflozin ameliorates glycemic control in db/db mice. • Luseogliflozin increases β-cell proliferation and decreases β-cell apoptosis. • Luseogliflozin preserves various β-cell-specific gene expression. • Luseogliflozin decreases various fibrosis-related factors in db

  8. Protective effects of SGLT2 inhibitor luseogliflozin on pancreatic β-cells in obese type 2 diabetic db/db mice

    International Nuclear Information System (INIS)

    Okauchi, Seizo; Shimoda, Masashi; Obata, Atsushi; Kimura, Tomohiko; Hirukawa, Hidenori; Kohara, Kenji; Mune, Tomoatsu; Kaku, Kohei; Kaneto, Hideaki

    2016-01-01

    It is well known that Sodium-Glucose Co-transporter 2 (SGLT2) inhibitors, new hypoglycemic agents, improve glycemic control by increasing urine glucose excretion, but it remained unclear how they exert protective effects on pancreatic β-cells. In this study, we examined the effects of SGLT2 inhibitor luseogliflozin on β-cell function and mass using obese type 2 diabetic db/db mice. Ten-week-old male diabetic db/db mice were treated with luseogliflozin 0.0025% or 0.01% in chow (Luse 0.0025% or Luse 0.01%) or vehicle (control) for 4 weeks. Urinary glucose excretion was increased in Luse groups (0.0025% and 0.01%) compared to control mice 3 days after the intervention. Fasting blood glucose levels were significantly lower in mice treated with Luse compared to control mice. Fasting serum insulin concentrations were significantly higher in mice treated with Luse compared to control mice. Triglyceride levels tended to be lower in Luse groups compared to control mice. In immunohistochemical study using pancreas tissues, β-cell mass was larger in Luse groups compared to control group which was due to the increase of β-cell proliferation and decrease of β-cell apoptosis. Furthermore, in gene analysis using isolated islets, insulin 1, insulin 2, MafA, PDX-1 and GLUT2 gene expression levels were significantly higher in Luse groups compared to control group. In contrast, expression levels of fibrosis-related gene such as TGFβ, fibronectin, collagen I and collagen III were significantly lower in Luse groups. In conclusion, SGLT2 inhibitor luseogliflozin ameliorates glycemic control and thus exerts protective effects on pancreatic β-cell mass and function. - Highlights: • SGLT2 inhibitor luseogliflozin ameliorates glycemic control in db/db mice. • Luseogliflozin increases β-cell proliferation and decreases β-cell apoptosis. • Luseogliflozin preserves various β-cell-specific gene expression. • Luseogliflozin decreases various fibrosis-related factors in db

  9. Differentiation of human induced pluripotent stem cells into insulin-like cell clusters with miR-186 and miR-375 by using chemical transfection.

    Science.gov (United States)

    Shaer, Anahita; Azarpira, Negar; Karimi, Mohammad Hosein

    2014-09-01

    Diabetes mellitus is characterized by either the inability to produce insulin or insensitivity to insulin secreted by the body. Islet cell replacement is an effective approach for diabetes treatment; however, it is not sufficient for all the diabetic patients. MicroRNAs (miRNAs) are a class of small noncoding RNAs that play an important role in mediating a broad and expanding range of biological activities, such as pancreas development. The present study aimed to develop a protocol to efficiently differentiate human induced pluripotent stem (iPS) cells into islet-like cell clusters (ILCs) in vitro by using miR-186 and miR-375. The human iPS colonies were transfected with hsa-miR-186 and hsa-miR-375 by using siPORT™ NeoFX™ Transfection Agent, and the differentiation was compared to controls. Total RNA was extracted 24 and 48 h after transfection. The gene expressions of insulin, NGN3, GLUT2, PAX4, PAX6, KIR6.2, NKX6.1, PDX1, Glucagon, and OCT4 were then evaluated through real-time qPCR. On the third day, the potency of the clusters was assessed in response to high glucose levels. Dithizone (DTZ) was used to identify the existence of the β-cells. Besides, the presence of insulin and NGN3 proteins was investigated by immunocytochemistry. Morphological changes were observed on the first day after the chemical transfection, and cell clusters were formed on the third day. The expression of pancreatic specific transcription factors was increased on the first day and significantly increased on the second day. The ILCs were positive for insulin and NGN3 proteins in the immunocytochemistry. Besides, the clusters were stained with DTZ and secreted insulin in glucose challenge test. Overexpression of miR-186 and miR-375 can be an alternative strategy for producing ILCs from the iPS cells in a short time. This work provides a new approach by using patient-specific iPSCs for β-cell replacement therapy in diabetic patients.

  10. In vitro phenotypic, genomic and proteomic characterization of a cytokine-resistant murine β-TC3 cell line.

    Directory of Open Access Journals (Sweden)

    Antonina Coppola

    Full Text Available Type 1 diabetes mellitus (T1DM is caused by the selective destruction of insulin-producing β-cells. This process is mediated by cells of the immune system through release of nitric oxide, free radicals and pro-inflammatory cytokines, which induce a complex network of intracellular signalling cascades, eventually affecting the expression of genes involved in β-cell survival.The aim of our study was to investigate possible mechanisms of resistance to cytokine-induced β-cell death. To this purpose, we created a cytokine-resistant β-cell line (β-TC3R by chronically treating the β-TC3 murine insulinoma cell line with IL-1β + IFN-γ. β-TC3R cells exhibited higher proliferation rate and resistance to cytokine-mediated cell death in comparison to the parental line. Interestingly, they maintained expression of β-cell specific markers, such as PDX1, NKX6.1, GLUT2 and insulin. The analysis of the secretory function showed that β-TC3R cells have impaired glucose-induced c-peptide release, which however was only moderately reduced after incubation with KCl and tolbutamide. Gene expression analysis showed that β-TC3R cells were characterized by downregulation of IL-1β and IFN-γ receptors and upregulation of SOCS3, the classical negative regulator of cytokines signaling. Comparative proteomic analysis showed specific upregulation of 35 proteins, mainly involved in cell death, stress response and folding. Among them, SUMO4, a negative feedback regulator in NF-kB and JAK/STAT signaling pathways, resulted hyper-expressed. Silencing of SUMO4 was able to restore sensitivity to cytokine-induced cell death in β-TC3R cells, suggesting it may play a key role in acquired cytokine resistance by blocking JAK/STAT and NF-kB lethal signaling.In conclusion, our study represents the first extensive proteomic characterization of a murine cytokine-resistant β-cell line, which might represent a useful tool for studying the mechanisms involved in resistance to

  11. Islet-like clusters derived from mesenchymal stem cells in Wharton's Jelly of the human umbilical cord for transplantation to control type 1 diabetes.

    Directory of Open Access Journals (Sweden)

    Kuo Ching Chao

    Full Text Available BACKGROUND: There is a widespread interest in developing renewable sources of islet-replacement tissue for type I diabetes mellitus. Human mesenchymal cells isolated from the Wharton's jelly of the umbilical cord (HUMSCs, which can be easily obtained and processed compared with embryonic and bone marrow stem cells, possess stem cell properties. HUMSCs may be a valuable source for the generation of islets. METHODOLOGY AND PRINCIPAL FINDINGS: HUMSCs were induced to transform into islet-like cell clusters in vitro through stepwise culturing in neuron-conditioned medium. To assess the functional stability of the islet-like cell clusters in vivo, these cell clusters were transplanted into the liver of streptozotocin-induced diabetic rats via laparotomy. Glucose tolerance was measured on week 12 after transplantation accompanied with immunohistochemistry and electron microscopy analysis. These islet-like cell clusters were shown to contain human C-peptide and release human insulin in response to physiological glucose levels. Real-time RT-PCR detected the expressions of insulin and other pancreatic beta-cell-related genes (Pdx1, Hlxb9, Nkx2.2, Nkx6.1, and Glut-2 in these islet-like cell clusters. The hyperglycemia and glucose intolerance in streptozotocin-induced diabetic rats was significantly alleviated after xenotransplantation of islet-like cell clusters, without the use of immunosuppressants. In addition to the existence of islet-like cell clusters in the liver, some special fused liver cells were also found, which characterized by human insulin and nuclei-positive staining and possessing secretory granules. CONCLUSIONS AND SIGNIFICANCE: In this study, we successfully differentiate HUMSCs into mature islet-like cell clusters, and these islet-like cell clusters possess insulin-producing ability in vitro and in vivo. HUMSCs in Wharton's Jelly of the umbilical cord seem to be the preferential source of stem cells to convert into insulin

  12. Macropolyhedral boron-containing cluster chemistry. Cluster opening and B-frame rearrangement in the reaction of B16H20 with [{(IrCl2(eta(5)-C5Me5)}(2)]. Synchrotron X-ray structures of [(eta(5)-C5Me5)(2)Ir2B16H17Cl] and [(eta(5)-C5Me5)(2)Ir2B16H15Cl

    Czech Academy of Sciences Publication Activity Database

    Carr, MJ.; Perera, SD.; Jelínek, Tomáš; Kilner, C. A.; Clegg, W.; Štíbr, Bohumil; Kennedy, J.D.

    2006-01-01

    Roč. 44, - (2006), s. 5221-5224 ISSN 1477-9226 R&D Projects: GA AV ČR(CZ) IAA400320601; GA ČR GA203/05/2646 Grant - others:EPSRC(GB) J/56929; EPSRC(GB) GR/L/49505; EPSRC(GB) R/61949 Institutional research plan: CEZ:AV0Z40320502 Keywords : intercluster bonding intimagy * matallaborane clusters * crystal-structures Subject RIV: CA - Inorganic Chemistry Impact factor: 3.012, year: 2006

  13. Studies of genetic variability of the glucose transporter 2 promoter in patients with type 2 diabetes mellitus

    DEFF Research Database (Denmark)

    Møller, A M; Jensen, N M; Pildal, J

    2001-01-01

    This study was performed to test the hypothesis that genetic variation in the promoter of the glucose transporter 2 (GLUT2) might predispose to prediabetic phenotypes or type 2 diabetes. A total of 1611 bp comprising the minimal promoter region of the GLUT2 gene were examined by combined single-s......-tolerant subjects. In conclusion, we found no evidence supporting the hypothesis that genetic variability in the minimal promoter of the GLUT2 is associated with type 2 diabetes or prediabetic phenotypes in the Danish population.......This study was performed to test the hypothesis that genetic variation in the promoter of the glucose transporter 2 (GLUT2) might predispose to prediabetic phenotypes or type 2 diabetes. A total of 1611 bp comprising the minimal promoter region of the GLUT2 gene were examined by combined single...

  14. [In vitro generation of insulin-producing cells from the neonatal rat bone marrow mesenchymal stem cells].

    Science.gov (United States)

    Li, Xiaohu; Huang, Haiyan; Liu, Xirong; Xia, Hongxia; Li, Mincai

    2015-03-01

    To observe the differentiation of the neonatal rat bone marrow mesenchymal stem cells (MSCs) into insulin-producing cells and detect the expressions of insulin, pancreatic duodenal homebox-1 (PDX-1) and nestin. MSCs were isolated from the neonatal rats and cultured in the modified medium composed of 10 μg/L human epidermal growth factor (EGF), 10 μg/L basic fibroblast growth factor (bFGF), 10 μg/L hepatocyte growth factor (HGF), 10 μg/L human B cell regulin, 20 mmol/L nicotinamide and 20 g/L B27. After the induction, the mRNA expressions of insulin, PDX-1 and nestin were examined by reverse transcription-PCR, and the insulin, PDX-1 and nestin protein levels were detected by immunocytochemistry. The insulin and PDX-1 mRNA expressions increased and the nestin mRNA expression decreased in the differentiation of the neonatal rat MSCs into insulin-producing cells. The nestin, PDX-1 and insulin proteins were co-expressed in insulin-producing cells. MSCs can be induced to differentiate into insulin-producing cells.

  15. Protective effect of bioflavonoid myricetin enhances carbohydrate metabolic enzymes and insulin signaling molecules in streptozotocin–cadmium induced diabetic nephrotoxic rats

    International Nuclear Information System (INIS)

    Kandasamy, Neelamegam; Ashokkumar, Natarajan

    2014-01-01

    Diabetic nephropathy is the kidney disease that occurs as a result of diabetes. The present study was aimed to evaluate the therapeutic potential of myricetin by assaying the activities of key enzymes of carbohydrate metabolism, insulin signaling molecules and renal function markers in streptozotocin (STZ)–cadmium (Cd) induced diabetic nephrotoxic rats. After myricetin treatment schedule, blood and tissue samples were collected to determine plasma glucose, insulin, hemoglobin, glycosylated hemoglobin and renal function markers, carbohydrate metabolic enzymes in the liver and insulin signaling molecules in the pancreas and skeletal muscle. A significant increase of plasma glucose, glycosylated hemoglobin, urea, uric acid, creatinine, blood urea nitrogen (BUN), urinary albumin, glycogen phosphorylase, glucose-6-phosphatase, and fructose-1,6-bisphosphatase and a significant decrease of plasma insulin, hemoglobin, hexokinase, glucose-6-phosphate dehydrogenase, glycogen and glycogen synthase with insulin signaling molecule expression were found in the STZ–Cd induced diabetic nephrotoxic rats. The administration of myricetin significantly normalizes the carbohydrate metabolic products like glucose, glycated hemoglobin, glycogen phosphorylase and gluconeogenic enzymes and renal function markers with increase insulin, glycogen, glycogen synthase and insulin signaling molecule expression like glucose transporter-2 (GLUT-2), glucose transporter-4 (GLUT-4), insulin receptor-1 (IRS-1), insulin receptor-2 (IRS-2) and protein kinase B (PKB). Based on the data, the protective effect of myricetin was confirmed by its histological annotation of the pancreas, liver and kidney tissues. These findings suggest that myricetin improved carbohydrate metabolism which subsequently enhances glucose utilization and renal function in STZ–Cd induced diabetic nephrotoxic rats. - Highlights: • Diabetic rats are more susceptible to cadmium nephrotoxicity. • Cadmium plays as a cumulative

  16. Hepatitis C virus induces a prediabetic state by directly impairing hepatic glucose metabolism in mice.

    Science.gov (United States)

    Lerat, Hervé; Imache, Mohamed Rabah; Polyte, Jacqueline; Gaudin, Aurore; Mercey, Marion; Donati, Flora; Baudesson, Camille; Higgs, Martin R; Picard, Alexandre; Magnan, Christophe; Foufelle, Fabienne; Pawlotsky, Jean-Michel

    2017-08-04

    Virus-related type 2 diabetes is commonly observed in individuals infected with the hepatitis C virus (HCV); however, the underlying molecular mechanisms remain unknown. Our aim was to unravel these mechanisms using FL-N/35 transgenic mice expressing the full HCV ORF. We observed that these mice displayed glucose intolerance and insulin resistance. We also found that Glut-2 membrane expression was reduced in FL-N/35 mice and that hepatocyte glucose uptake was perturbed, partly accounting for the HCV-induced glucose intolerance in these mice. Early steps of the hepatic insulin signaling pathway, from IRS2 to PDK1 phosphorylation, were constitutively impaired in FL-N/35 primary hepatocytes via deregulation of TNFα/SOCS3. Higher hepatic glucose production was observed in the HCV mice, despite higher fasting insulinemia, concomitant with decreased expression of hepatic gluconeogenic genes. Akt kinase activity was higher in HCV mice than in WT mice, but Akt-dependent phosphorylation of the forkhead transcription factor FoxO1 at serine 256, which triggers its nuclear exclusion, was lower in HCV mouse livers. These findings indicate an uncoupling of the canonical Akt/FoxO1 pathway in HCV protein-expressing hepatocytes. Thus, the expression of HCV proteins in the liver is sufficient to induce insulin resistance by impairing insulin signaling and glucose uptake. In conclusion, we observed a complete set of events leading to a prediabetic state in HCV-transgenic mice, providing a valuable mechanistic explanation for HCV-induced diabetes in humans. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  17. Protective effect of bioflavonoid myricetin enhances carbohydrate metabolic enzymes and insulin signaling molecules in streptozotocin–cadmium induced diabetic nephrotoxic rats

    Energy Technology Data Exchange (ETDEWEB)

    Kandasamy, Neelamegam; Ashokkumar, Natarajan, E-mail: npashokkumar1@gmail.com

    2014-09-01

    Diabetic nephropathy is the kidney disease that occurs as a result of diabetes. The present study was aimed to evaluate the therapeutic potential of myricetin by assaying the activities of key enzymes of carbohydrate metabolism, insulin signaling molecules and renal function markers in streptozotocin (STZ)–cadmium (Cd) induced diabetic nephrotoxic rats. After myricetin treatment schedule, blood and tissue samples were collected to determine plasma glucose, insulin, hemoglobin, glycosylated hemoglobin and renal function markers, carbohydrate metabolic enzymes in the liver and insulin signaling molecules in the pancreas and skeletal muscle. A significant increase of plasma glucose, glycosylated hemoglobin, urea, uric acid, creatinine, blood urea nitrogen (BUN), urinary albumin, glycogen phosphorylase, glucose-6-phosphatase, and fructose-1,6-bisphosphatase and a significant decrease of plasma insulin, hemoglobin, hexokinase, glucose-6-phosphate dehydrogenase, glycogen and glycogen synthase with insulin signaling molecule expression were found in the STZ–Cd induced diabetic nephrotoxic rats. The administration of myricetin significantly normalizes the carbohydrate metabolic products like glucose, glycated hemoglobin, glycogen phosphorylase and gluconeogenic enzymes and renal function markers with increase insulin, glycogen, glycogen synthase and insulin signaling molecule expression like glucose transporter-2 (GLUT-2), glucose transporter-4 (GLUT-4), insulin receptor-1 (IRS-1), insulin receptor-2 (IRS-2) and protein kinase B (PKB). Based on the data, the protective effect of myricetin was confirmed by its histological annotation of the pancreas, liver and kidney tissues. These findings suggest that myricetin improved carbohydrate metabolism which subsequently enhances glucose utilization and renal function in STZ–Cd induced diabetic nephrotoxic rats. - Highlights: • Diabetic rats are more susceptible to cadmium nephrotoxicity. • Cadmium plays as a cumulative

  18. Protective effect of bioflavonoid myricetin enhances carbohydrate metabolic enzymes and insulin signaling molecules in streptozotocin-cadmium induced diabetic nephrotoxic rats.

    Science.gov (United States)

    Kandasamy, Neelamegam; Ashokkumar, Natarajan

    2014-09-01

    Diabetic nephropathy is the kidney disease that occurs as a result of diabetes. The present study was aimed to evaluate the therapeutic potential of myricetin by assaying the activities of key enzymes of carbohydrate metabolism, insulin signaling molecules and renal function markers in streptozotocin (STZ)-cadmium (Cd) induced diabetic nephrotoxic rats. After myricetin treatment schedule, blood and tissue samples were collected to determine plasma glucose, insulin, hemoglobin, glycosylated hemoglobin and renal function markers, carbohydrate metabolic enzymes in the liver and insulin signaling molecules in the pancreas and skeletal muscle. A significant increase of plasma glucose, glycosylated hemoglobin, urea, uric acid, creatinine, blood urea nitrogen (BUN), urinary albumin, glycogen phosphorylase, glucose-6-phosphatase, and fructose-1,6-bisphosphatase and a significant decrease of plasma insulin, hemoglobin, hexokinase, glucose-6-phosphate dehydrogenase, glycogen and glycogen synthase with insulin signaling molecule expression were found in the STZ-Cd induced diabetic nephrotoxic rats. The administration of myricetin significantly normalizes the carbohydrate metabolic products like glucose, glycated hemoglobin, glycogen phosphorylase and gluconeogenic enzymes and renal function markers with increase insulin, glycogen, glycogen synthase and insulin signaling molecule expression like glucose transporter-2 (GLUT-2), glucose transporter-4 (GLUT-4), insulin receptor-1 (IRS-1), insulin receptor-2 (IRS-2) and protein kinase B (PKB). Based on the data, the protective effect of myricetin was confirmed by its histological annotation of the pancreas, liver and kidney tissues. These findings suggest that myricetin improved carbohydrate metabolism which subsequently enhances glucose utilization and renal function in STZ-Cd induced diabetic nephrotoxic rats. Copyright © 2014 Elsevier Inc. All rights reserved.

  19. 12038_2016_9616_Supplementary 1..4

    Indian Academy of Sciences (India)

    homeostasis, autoimmunity, responses to infection, cancers and inflammation. ... CD40+CD4+T cells involved in type-I diabetes through binding of Gal-9 with CD40. ... ForssmanGlycosphingolipid; FOXP3: Forkhead Box P3; GLUT 2: Glucose.

  20. Selected Phytochemicals and Culinary Plant Extracts Inhibit Fructose Uptake in Caco-2 Cells.

    Science.gov (United States)

    Lee, Yurim; Lim, Yeni; Kwon, Oran

    2015-09-18

    This study compared the ability of nine culinary plant extracts containing a wide array of phytochemicals to inhibit fructose uptake and then explored the involvement of intestinal fructose transporters and phytochemicals for selected samples. The chemical signature was characterized by high performance liquid chromatography with mass spectrometry. Inhibition of [(14)C]-fructose uptake was tested by using human intestinal Caco-2 cells. Then, the relative contribution of the two apical-facing intestinal fructose transporters, GLUT2 and GLUT5, and the signature components for fructose uptake inhibition was confirmed in naive, phloretin-treated and forskolin-treated Caco-2 cells. HPLC/MS analysis of the chemical signature revealed that guava leaf contained quercetin and catechin, and turmeric contained curcumin, bisdemethoxycurcumin and dimethoxycurcumin. Similar inhibition of fructose uptake (by ~50%) was observed with guava leaf and turmeric in Caco-2 cells, but with a higher contribution of GLUT2 for turmeric and that of GLUT5 for guava leaf. The data suggested that, in turmeric, demethoxycurcumin specifically contributed to GLUT2-mediated fructose uptake inhibition, and curcumin did the same to GLUT5-mediated fructose uptake inhibition, but GLUT2 inhibition was more potent. By contrast, in guava leaf, catechin specifically contributed to GLUT5-mediated fructose uptake inhibition, and quercetin affected both GLUT5- and GLUT2-mediated fructose uptake inhibition, resulting in the higher contribution of GLUT5. These results suggest that demethoxycurcumin is an important contributor to GLUT2-mediated fructose uptake inhibition for turmeric extract, and catechin is the same to GLUT5-mediated fructose uptake inhibition for guava leaf extract. Quercetin, curcumin and bisdemethoxycurcumin contributed to both GLUT5- and GLUT2-mediated fructose uptake inhibition, but the contribution to GLUT5 inhibition was higher than the contribution to GLUT2 inhibition.

  1. Prep1, A Homeodomain Transcription Factor Involved in Glucose and Lipid Metabolism

    Directory of Open Access Journals (Sweden)

    Francesco Oriente

    2018-06-01

    Full Text Available The three-amino acid loop extension (TALE homeodomain proteins are a family of transcription factor including the mammalian Pbx, MEIS and Prep proteins. TALE proteins can bind other transcription factors such as Pdx-1 and play an important role in the regulation of glucose metabolism. Experiments performed in mutant mice have shown that while the single Pbx1 or Pdx-1 knockout mice feature pancreatic islet malformations, impaired glucose tolerance and hypoinsulinemia, the trans-heterozygous Pbx1+/−Pdx1+/− mice develop age-dependent overt diabetes mellitus. In contrast, Prep1 plays a different role with respect to these proteins. Indeed, Prep1 hypomorphic mice, expressing low levels of protein, feature pancreatic islet hypoplasia accompanied by hypoinsulinemia similar to Pbx1 or Pdx1. Nevertheless, these animals show increased insulin sensitivity in skeletal muscle, liver and adipose tissue accompanied by protection from streptozotocin-induced diabetes. In addition, Prep1 hypomorphic mice feature reduced triglyceride synthesis and do not develop steatohepatitis after a methionine and coline deficient diet. In this review we have underlined how important metabolic functions are controlled by TALE proteins, in particular by Prep1, leading to hypothesis that its suppression might represent beneficial effect in the care of metabolic diseases.

  2. Vitamin B6 deficient plants display increased sensitivity to high light and photo-oxidative stress

    Directory of Open Access Journals (Sweden)

    Rumeau Dominique

    2009-11-01

    Full Text Available Abstract Background Vitamin B6 is a collective term for a group of six interconvertible compounds: pyridoxine, pyridoxal, pyridoxamine and their phosphorylated derivatives. Vitamin B6 plays essential roles as a cofactor in a range of biochemical reactions. In addition, vitamin B6 is able to quench reactive oxygen species in vitro, and exogenously applied vitamin B6 protects plant cells against cell death induced by singlet oxygen (1O2. These results raise the important question as to whether plants employ vitamin B6 as an antioxidant to protect themselves against reactive oxygen species. Results The pdx1.3 mutation affects the vitamin B6 biosynthesis enzyme, pyridoxal synthase (PDX1, and leads to a reduction of the vitamin B6 concentration in Arabidopsis thaliana leaves. Although leaves of the pdx1.3 Arabidopsis mutant contained less chlorophyll than wild-type leaves, we found that vitamin B6 deficiency did not significantly impact photosynthetic performance or shoot and root growth. Chlorophyll loss was associated with an increase in the chlorophyll a/b ratio and a selective decrease in the abundance of several PSII antenna proteins (Lhcb1/2, Lhcb6. These changes were strongly dependent on light intensity, with high light amplifying the difference between pdx1.3 and the wild type. When leaf discs were exposed to exogenous 1O2, lipid peroxidation in pdx1.3 was increased relative to the wild type; this effect was not observed with superoxide or hydrogen peroxide. When leaf discs or whole plants were exposed to excess light energy, 1O2-mediated lipid peroxidation was enhanced in leaves of the pdx1.3 mutant relative to the wild type. High light also caused an increased level of 1O2 in vitamin B6-deficient leaves. Combining the pdx1.3 mutation with mutations affecting the level of 'classical' quenchers of 1O2 (zeaxanthin, tocopherols resulted in a highly photosensitive phenotype. Conclusion This study demonstrates that vitamin B6 has a function in

  3. Advanced Glycation End-Products affect transcription factors regulating insulin gene expression

    International Nuclear Information System (INIS)

    Puddu, A.; Storace, D.; Odetti, P.; Viviani, G.L.

    2010-01-01

    Advanced Glycation End-Products (AGEs) are generated by the covalent interaction of reducing sugars with proteins, lipids or nucleic acids. AGEs are implicated in diabetic complications and pancreatic β-cell dysfunction. We previously demonstrated that exposure of the pancreatic islet cell line HIT-T15 to high concentrations of AGEs leads to a significant decrease of insulin secretion and content. Insulin gene transcription is positively regulated by the beta cell specific transcription factor PDX-1 (Pancreatic and Duodenal Homeobox-1). On the contrary, the forkhead transcription factor FoxO1 inhibits PDX-1 gene transcription. Activity of FoxO1 is regulated by post-translational modifications: phosphorylation deactivates FoxO1, and acetylation prevents FoxO1 ubiquitination. In this work we investigated whether AGEs affect expression and subcellular localization of PDX-1 and FoxO1. HIT-T15 cells were cultured for 5 days in presence of AGEs. Cells were then lysed and processed for subcellular fractionation. We determined intracellular insulin content, then we assessed the expression and subcellular localization of PDX-1, FoxO1, phosphoFoxO1 and acetylFoxO1. As expected intracellular insulin content was lower in HIT-T15 cells cultured with AGEs. The results showed that AGEs decreased expression and nuclear localization of PDX-1, reduced phosphorylation of FoxO1, and increased expression and acetylation of FoxO1. These results suggest that AGEs decrease insulin content unbalancing transcription factors regulating insulin gene expression.

  4. Poly(lactic-co-glycolic) acid loaded nano-insulin has greater potentials of combating arsenic induced hyperglycemia in mice: Some novel findings

    Energy Technology Data Exchange (ETDEWEB)

    Samadder, Asmita; Das, Jayeeta; Das, Sreemanti; De, Arnab; Saha, Santu Kumar; Bhattacharyya, Soumya Sundar; Khuda-Bukhsh, Anisur Rahman, E-mail: prof_arkb@yahoo.co.in

    2013-02-15

    Diabetes is a menacing problem, particularly to inhabitants of groundwater arsenic contaminated areas needing new medical approaches. This study examines if PLGA loaded nano-insulin (NIn), administered either intraperitoneally (i.p.) or through oral route, has a greater cost-effective anti-hyperglycemic potential than that of insulin in chronically arsenite-fed hyperglycemic mice. The particle size, morphology and zeta potential of nano-insulin were determined using dynamic light scattering method, scanning electronic and atomic force microscopies. The ability of the nano-insulin (NIn) to cross the blood–brain barrier (BBB) was also checked. Circular dichroic spectroscopic (CD) data of insulin and nano-insulin in presence or absence of arsenic were compared. Several diabetic markers in different groups of experimental and control mice were assessed. The mitochondrial functioning through indices like cytochrome c, pyruvate-kinase, glucokinase, ATP/ADP ratio, mitochondrial membrane potential, cell membrane potential and calcium-ion level was also evaluated. Expressions of the relevant marker proteins and mRNAs like insulin, GLUT2, GLUT4, IRS1, IRS2, UCP2, PI3, PPARγ, CYP1A1, Bcl2, caspase3 and p38 for tracking-down the signaling cascade were also analyzed. Results revealed that i.p.-injected nano-encapsulated-insulin showed better results; NIn, due to its smaller size, faster mobility, site-specific release, could cross BBB and showed positive modulation in mitochondrial signaling cascades and other downstream signaling molecules in reducing arsenic-induced-hyperglycemia. CD data indicated that nano-insulin had less distorted secondary structure as compared with that of insulin in presence of arsenic. Thus, overall analyses revealed that PLGA nano-insulin showed better efficacy in combating arsenite-induced-hyperglycemia than that of insulin and therefore, has greater potentials for use in nano-encapsulated form. - Highlights: ► PLGA encapsulated nano

  5. Poly(lactic-co-glycolic) acid loaded nano-insulin has greater potentials of combating arsenic induced hyperglycemia in mice: Some novel findings

    International Nuclear Information System (INIS)

    Samadder, Asmita; Das, Jayeeta; Das, Sreemanti; De, Arnab; Saha, Santu Kumar; Bhattacharyya, Soumya Sundar; Khuda-Bukhsh, Anisur Rahman

    2013-01-01

    Diabetes is a menacing problem, particularly to inhabitants of groundwater arsenic contaminated areas needing new medical approaches. This study examines if PLGA loaded nano-insulin (NIn), administered either intraperitoneally (i.p.) or through oral route, has a greater cost-effective anti-hyperglycemic potential than that of insulin in chronically arsenite-fed hyperglycemic mice. The particle size, morphology and zeta potential of nano-insulin were determined using dynamic light scattering method, scanning electronic and atomic force microscopies. The ability of the nano-insulin (NIn) to cross the blood–brain barrier (BBB) was also checked. Circular dichroic spectroscopic (CD) data of insulin and nano-insulin in presence or absence of arsenic were compared. Several diabetic markers in different groups of experimental and control mice were assessed. The mitochondrial functioning through indices like cytochrome c, pyruvate-kinase, glucokinase, ATP/ADP ratio, mitochondrial membrane potential, cell membrane potential and calcium-ion level was also evaluated. Expressions of the relevant marker proteins and mRNAs like insulin, GLUT2, GLUT4, IRS1, IRS2, UCP2, PI3, PPARγ, CYP1A1, Bcl2, caspase3 and p38 for tracking-down the signaling cascade were also analyzed. Results revealed that i.p.-injected nano-encapsulated-insulin showed better results; NIn, due to its smaller size, faster mobility, site-specific release, could cross BBB and showed positive modulation in mitochondrial signaling cascades and other downstream signaling molecules in reducing arsenic-induced-hyperglycemia. CD data indicated that nano-insulin had less distorted secondary structure as compared with that of insulin in presence of arsenic. Thus, overall analyses revealed that PLGA nano-insulin showed better efficacy in combating arsenite-induced-hyperglycemia than that of insulin and therefore, has greater potentials for use in nano-encapsulated form. - Highlights: ► PLGA encapsulated nano

  6. Studies of genetic variability of the glucose transporter 2 promoter in patients with type 2 diabetes mellitus

    DEFF Research Database (Denmark)

    Møller, A M; Jensen, N M; Pildal, J

    2001-01-01

    This study was performed to test the hypothesis that genetic variation in the promoter of the glucose transporter 2 (GLUT2) might predispose to prediabetic phenotypes or type 2 diabetes. A total of 1611 bp comprising the minimal promoter region of the GLUT2 gene were examined by combined single......-tolerant subjects. In conclusion, we found no evidence supporting the hypothesis that genetic variability in the minimal promoter of the GLUT2 is associated with type 2 diabetes or prediabetic phenotypes in the Danish population.......-strand conformational polymorphism and heteroduplex analysis followed by direct sequencing of identified variants on genomic DNA from 96 randomly recruited Danish type 2 diabetic patients. We identified 4 nucleotide variants, -447g-->a, -149c-->a, -122t-->c, and -44g-->a. None of the variants were positioned in known...

  7. From the Cover: Cell-replacement therapy for diabetes: Generating functional insulin-producing tissue from adult human liver cells

    Science.gov (United States)

    Sapir, Tamar; Shternhall, Keren; Meivar-Levy, Irit; Blumenfeld, Tamar; Cohen, Hamutal; Skutelsky, Ehud; Eventov-Friedman, Smadar; Barshack, Iris; Goldberg, Iris; Pri-Chen, Sarah; Ben-Dor, Lya; Polak-Charcon, Sylvie; Karasik, Avraham; Shimon, Ilan; Mor, Eytan; Ferber, Sarah

    2005-05-01

    Shortage in tissue availability from cadaver donors and the need for life-long immunosuppression severely restrict the large-scale application of cell-replacement therapy for diabetic patients. This study suggests the potential use of adult human liver as alternate tissue for autologous beta-cell-replacement therapy. By using pancreatic and duodenal homeobox gene 1 (PDX-1) and soluble factors, we induced a comprehensive developmental shift of adult human liver cells into functional insulin-producing cells. PDX-1-treated human liver cells express insulin, store it in defined granules, and secrete the hormone in a glucose-regulated manner. When transplanted under the renal capsule of diabetic, immunodeficient mice, the cells ameliorated hyperglycemia for prolonged periods of time. Inducing developmental redirection of adult liver offers the potential of a cell-replacement therapy for diabetics by allowing the patient to be the donor of his own insulin-producing tissue. pancreas | transdifferentiation

  8. An autocrine γ-aminobutyric acid signaling system exists in pancreatic β-cell progenitors of fetal and postnatal mice.

    Science.gov (United States)

    Feng, Mary M; Xiang, Yun-Yan; Wang, Shuanglian; Lu, Wei-Yang

    2013-01-01

    Gamma-aminobutyric acid (GABA) is produced and secreted by adult pancreatic β-cells, which also express GABA receptors mediating autocrine signaling and regulating β-cell proliferation. However, whether the autocrine GABA signaling involves in β-cell progenitor development or maturation remains uncertain. By means of immunohistochemistry we analyzed the expression profiles of the GABA synthesizing enzyme glutamic acid decarboxylase (GAD) and the α1-subunit of type-A GABA receptor (GABAARα1) in the pancreas of mice at embryonic day 15.5 (E15.5), E18.5, postnatal day 1 (P1) and P7. Our data showed that at E15.5 the pancreatic and duodenum homeobox-1 (Pdx1) was expressed in the majority of cells in the developing pancreata. Notably, insulin immunoreactivity was identified in a subpopulation of pancreatic cells with a high level of Pdx1 expression. About 80% of the high-level Pdx-1 expressing cells in the pancreas expressed GAD and GABAARα1 at all pancreatic developmental stages. In contrast, only about 30% of the high-level Pdx-1 expressing cells in the E15.5 pancreas expressed insulin; i.e., a large number of GAD/GABAARα1-expressing cells did not express insulin at this early developmental stage. The expression level of GAD and GABAARα1 increased steadily, and progressively more GAD/GABAARα1-expressing cells expressed insulin in the course of pancreatic development. These results suggest that 1) GABA signaling proteins appear in β-cell progenitors prior to insulin expression; and 2) the increased expression of GABA signaling proteins may be involved in β-cell progenitor maturation.

  9. Nanotopography Promotes Pancreatic Differentiation of Human Embryonic Stem Cells and Induced Pluripotent Stem Cells.

    Science.gov (United States)

    Kim, Jong Hyun; Kim, Hyung Woo; Cha, Kyoung Je; Han, Jiyou; Jang, Yu Jin; Kim, Dong Sung; Kim, Jong-Hoon

    2016-03-22

    Although previous studies suggest that nanotopographical features influence properties and behaviors of stem cells, only a few studies have attempted to derive clinically useful somatic cells from human pluripotent stem cells using nanopatterned surfaces. In the present study, we report that polystyrene nanopore-patterned surfaces significantly promote the pancreatic differentiation of human embryonic and induced pluripotent stem cells. We compared different diameters of nanopores and showed that 200 nm nanopore-patterned surfaces highly upregulated the expression of PDX1, a critical transcription factor for pancreatic development, leading to an approximately 3-fold increase in the percentage of differentiating PDX1(+) pancreatic progenitors compared with control flat surfaces. Furthermore, in the presence of biochemical factors, 200 nm nanopore-patterned surfaces profoundly enhanced the derivation of pancreatic endocrine cells producing insulin, glucagon, or somatostatin. We also demonstrate that nanopore-patterned surface-induced upregulation of PDX1 is associated with downregulation of TAZ, suggesting the potential role of TAZ in nanopore-patterned surface-mediated mechanotransduction. Our study suggests that appropriate cytokine treatments combined with nanotopographical stimulation could be a powerful tool for deriving a high purity of desired cells from human pluripotent stem cells.

  10. It takes two to tango: defining an essential second active site in pyridoxal 5'-phosphate synthase.

    Directory of Open Access Journals (Sweden)

    Cyril Moccand

    Full Text Available The prevalent de novo biosynthetic pathway of vitamin B6 involves only two enzymes (Pdx1 and Pdx2 that form an ornate multisubunit complex functioning as a glutamine amidotransferase. The synthase subunit, Pdx1, utilizes ribose 5-phosphate and glyceraldehyde 3-phosphate, as well as ammonia derived from the glutaminase activity of Pdx2 to directly form the cofactor vitamer, pyridoxal 5'-phosphate. Given the fact that a single enzyme performs the majority of the chemistry behind this reaction, a complicated mechanism is anticipated. Recently, the individual steps along the reaction co-ordinate are beginning to be unraveled. In particular, the binding of the pentose substrate and the first steps of the reaction have been elucidated but it is not known if the latter part of the chemistry, involving the triose sugar, takes place in the same or a disparate site. Here, we demonstrate through the use of enzyme assays, enzyme kinetics, and mutagenesis studies that indeed a second site is involved in binding the triose sugar and moreover, is the location of the final vitamin product, pyridoxal 5'-phosphate. Furthermore, we show that product release is triggered by the presence of a PLP-dependent enzyme. Finally, we provide evidence that a single arginine residue of the C terminus of Pdx1 is responsible for coordinating co-operativity in this elaborate protein machinery.

  11. World Oil: Coping With the Dangers of Success. Worldwatch Paper 66.

    Science.gov (United States)

    Flavin, Christopher

    This publication examines various topics and issues related to the world oil situation. Major areas considered are: (1) the nature and consequences of the current oil glut; (2) a historical overview of the petroleum era (with analyses of the three time periods of 1900-1973, 1973-1979, and 1979-1981); (3) the geopolitics of oil (including data on…

  12. Short-term insulin treatment prevents the diabetogenic action of streptozotocin in rats

    DEFF Research Database (Denmark)

    Thulesen, J; Orskov, C; Holst, J J

    1997-01-01

    Streptozotocin, which induces diabetes mellitus in experimental animals, has been reported to be taken up by beta-cells by means of the glucose transporter 2 (GLUT2) and then reduce the cellular level of NAD+, leading to necrosis of the beta-cells. We investigated the effect of insulin pretreatme...

  13. Experimental type II diabetes and related models of impaired glucose metabolism differentially regulate glucose transporters at the proximal tubule brush border membrane.

    Science.gov (United States)

    Chichger, Havovi; Cleasby, Mark E; Srai, Surjit K; Unwin, Robert J; Debnam, Edward S; Marks, Joanne

    2016-06-01

    What is the central question of this study? Although SGLT2 inhibitors represent a promising treatment for patients suffering from diabetic nephropathy, the influence of metabolic disruption on the expression and function of glucose transporters is largely unknown. What is the main finding and its importance? In vivo models of metabolic disruption (Goto-Kakizaki type II diabetic rat and junk-food diet) demonstrate increased expression of SGLT1, SGLT2 and GLUT2 in the proximal tubule brush border. In the type II diabetic model, this is accompanied by increased SGLT- and GLUT-mediated glucose uptake. A fasted model of metabolic disruption (high-fat diet) demonstrated increased GLUT2 expression only. The differential alterations of glucose transporters in response to varying metabolic stress offer insight into the therapeutic value of inhibitors. SGLT2 inhibitors are now in clinical use to reduce hyperglycaemia in type II diabetes. However, renal glucose reabsorption across the brush border membrane (BBM) is not completely understood in diabetes. Increased consumption of a Western diet is strongly linked to type II diabetes. This study aimed to investigate the adaptations that occur in renal glucose transporters in response to experimental models of diet-induced insulin resistance. The study used Goto-Kakizaki type II diabetic rats and normal rats rendered insulin resistant using junk-food or high-fat diets. Levels of protein kinase C-βI (PKC-βI), GLUT2, SGLT1 and SGLT2 were determined by Western blotting of purified renal BBM. GLUT- and SGLT-mediated d-[(3) H]glucose uptake by BBM vesicles was measured in the presence and absence of the SGLT inhibitor phlorizin. GLUT- and SGLT-mediated glucose transport was elevated in type II diabetic rats, accompanied by increased expression of GLUT2, its upstream regulator PKC-βI and SGLT1 protein. Junk-food and high-fat diet feeding also caused higher membrane expression of GLUT2 and its upstream regulator PKC

  14. Molecular diagnosis of maturity-onset diabetes of the young (MODY) in Turkish children by using targeted next-generation sequencing.

    Science.gov (United States)

    Anık, Ahmet; Çatlı, Gönül; Abacı, Ayhan; Sarı, Erkan; Yeşilkaya, Ediz; Korkmaz, Hüseyin Anıl; Demir, Korcan; Altıncık, Ayça; Tuhan, Hale Ünver; Kızıldağ, Sefa; Özkan, Behzat; Ceylaner, Serdar; Böber, Ece

    2015-11-01

    To perform molecular analysis of pediatric maturity onset diabetes of the young (MODY) patients by next-generation sequencing, which enables simultaneous analysis of multiple genes in a single test, to determine the genetic etiology of a group of Turkish children clinically diagnosed as MODY, and to assess genotype-phenotype relationship. Forty-two children diagnosed with MODY and their parents were enrolled in the study. Clinical and laboratory characteristics of the patients at the time of diagnosis were obtained from hospital records. Molecular analyses of GCK, HNF1A, HNF4A, HNF1B, PDX1, NEUROD1, KLF11, CEL, PAX4, INS, and BLK genes were performed on genomic DNA by using next-generation sequencing. Pathogenicity for novel mutations was assessed by bioinformatics prediction software programs and segregation analyses. A mutation in MODY genes was identified in 12 (29%) of the cases. GCK mutations were detected in eight cases, and HNF1B, HNF1A, PDX1, and BLK mutations in the others. We identified five novel missense mutations - three in GCK (p.Val338Met, p.Cys252Ser, and p.Val86Ala), one in HNF1A (p.Cys241Ter), and one in PDX1 (p.Gly55Asp), which we believe to be pathogenic. The results of this study showed that mutations in the GCK gene are the leading cause of MODY in our population. Moreover, genetic diagnosis could be made in 29% of Turkish patients, and five novel mutations were identified.

  15. Pancreas developing markers expressed on human mononucleated umbilical cord blood cells

    International Nuclear Information System (INIS)

    Pessina, A.; Eletti, B.; Croera, C.; Savalli, N.; Diodovich, C.; Gribaldo, L.

    2004-01-01

    Haematopoietic system represents the main source of haematopoietic stem cells and probably of multipotential adult progenitor cells and mesenchimal stem cells at first described as colony forming unit-fibroblast. Whereas there are many studies on the gene expression profile of the different precursors along their haematopoietic differentiation, few data (sometimes conflicting) have been reported about the phenotype of the cells (present in bone marrow and possibly in cord blood) able to differentiate into non-haematopoietic cells. As both postnatal bone marrow and umbilical cord blood contain nestin positive cells able to proliferate and differentiate into the main neural phenotype (neuron, astroglia and oligodendroglia) many authors considered nestin a neuroepithelial precursor marker that seems to be essential also in multipotential progenitor cells of pancreas present both in rat and in human pancreatic islets (called nestin positive islet derived progenitors). Although the importance of nestin in these cells appears to be evident, it remains yet to clarify the number and the sequential expression of the genes coding all the transcription factors essential for beta cells differentiation and therefore the conditions able to induce the expression of many important transcription factors genes such as isl-1, pax-4, pdx-1 and ngn-3. Among them pdx-1 is a gene essential for pancreas development which is able to control ngn-3 in activating the expression of other differentiation factors for endocrine cells. Here, we describe for the first time in human umbilical cord blood cells (UCB) the pattern of expression of a panel of markers (nestin, CK-8, CK-18) and transcription factors (Isl-1, Pdx-1, Pax-4, Ngn-3) considered important for beta cells differentiation. Our data demonstrate that UCB contains a cell population having a phenotype very similar to endocrine cell precursors in transition to beta cells

  16. β-MSCs: successful fusion of MSCs with β-cells results in a β-cell like phenotype.

    Science.gov (United States)

    Azizi, Zahra; Lange, Claudia; Paroni, Federico; Ardestani, Amin; Meyer, Anke; Wu, Yonghua; Zander, Axel R; Westenfelder, Christof; Maedler, Kathrin

    2016-08-02

    Bone marrow mesenchymal stromal cells (MSC) have anti-inflammatory, anti-apoptotic and immunosuppressive properties and are a potent source for cell therapy. Cell fusion has been proposed for rapid generation of functional new reprogrammed cells. In this study, we aimed to establish a fusion protocol of bone marrow-derived human MSCs with the rat beta-cell line (INS-1E) as well as human isolated pancreatic islets in order to generate insulin producing beta-MSCs as a cell-based treatment for diabetes.Human eGFP+ puromycin+ MSCs were co-cultured with either stably mCherry-expressing rat INS-1E cells or human dispersed islet cells and treated with phytohemagglutinin (PHA-P) and polyethylene glycol (PEG) to induce fusion. MSCs and fused cells were selected by puromycin treatment.With an improved fusion protocol, 29.8 ± 2.9% of all MSCs were β-MSC heterokaryons based on double positivity for mCherry and eGFP.After fusion and puromycin selection, human NKX6.1 and insulin as well as rat Neurod1, Nkx2.2, MafA, Pdx1 and Ins1 mRNA were highly elevated in fused human MSC/INS-1E cells, compared to the mixed control population. Such induction of beta-cell markers was confirmed in fused human MSC/human dispersed islet cells, which showed elevated NEUROD1, NKX2.2, MAFA, PDX1 and insulin mRNA compared to the mixed control. Fused cells had higher insulin content and improved insulin secretion compared to the mixed control and insulin positive beta-MSCs also expressed nuclear PDX1. We established a protocol for fusion of human MSCs and beta cells, which resulted in a beta cell like phenotype. This could be a novel tool for cell-based therapies of diabetes.

  17. Resveratrol Ameliorates the Maturation Process of β-Cell-Like Cells Obtained from an Optimized Differentiation Protocol of Human Embryonic Stem Cells

    Science.gov (United States)

    Pezzolla, Daniela; López-Beas, Javier; Lachaud, Christian C.; Domínguez-Rodríguez, Alejandro; Smani, Tarik; Hmadcha, Abdelkrim; Soria, Bernat

    2015-01-01

    Human embryonic stem cells (hESCs) retain the extraordinary capacity to differentiate into different cell types of an adult organism, including pancreatic β-cells. For this particular lineage, although a lot of effort has been made in the last ten years to achieve an efficient and reproducible differentiation protocol, it was not until recently that this aim was roughly accomplished. Besides, several studies evidenced the impact of resveratrol (RSV) on insulin secretion, even though the mechanism by which this polyphenol potentiates glucose-stimulated insulin secretion (GSIS) is still not clear. The aim of this study was to optimize an efficient differentiation protocol that mimics in vivo pancreatic organogenesis and to investigate whether RSV may improve the final maturation step to obtain functional insulin-secreting cells. Our results indicate that treatment of hESCs (HS-181) with activin-A induced definitive endoderm differentiation as detected by the expression of SOX17 and FOXA2. Addition of retinoic acid (RA), Noggin and Cyclopamine promoted pancreatic differentiation as indicated by the expression of the early pancreatic progenitor markers ISL1, NGN3 and PDX1. Moreover, during maturation in suspension culture, differentiating cells assembled in islet-like clusters, which expressed specific endocrine markers such as PDX1, SST, GCG and INS. Similar results were confirmed with the human induced Pluripotent Stem Cell (hiPSC) line MSUH-001. Finally, differentiation protocols incorporating RSV treatment yielded numerous insulin-positive cells, induced significantly higher PDX1 expression and were able to transiently normalize glycaemia when transplanted in streptozotocin (STZ) induced diabetic mice thus promoting its survival. In conclusion, our strategy allows the efficient differentiation of hESCs into pancreatic endoderm capable of generating β-cell-like cells and demonstrates that RSV improves the maturation process. PMID:25774684

  18. Detection of expressional changes induced by intrauterine growth restriction in the developing rat pancreas.

    Science.gov (United States)

    Zhang, Lin; Chen, Wei; Dai, Yuee; Zhu, Ziyang; Liu, Qianqi

    2016-07-01

    Intrauterine growth retardation (IUGR) is a disorder that can result in permanent changes in the physiology and metabolism of the newborn, which increased the risk of disease in adulthood. Evidence supports IUGR as a risk factor for the development of diabetes mellitus, which could reflect changes in pancreas developmental pathways. We sought to characterize the IUGR-induced alterations of the complex pathways of pancreas development in a rat model of IUGR. We analyzed the pancreases of Sprague Dawley rats after inducing IUGR by feeding a maternal low calorie diet from gestational day 1 until term. IUGR altered the pancreatic structure, islet areas, and islet quantities and resulted in abnormal morphological changes during pancreatic development, as determined by HE staining and light microscopy. We identified multiple differentially expressed genes in the pancreas by RT-PCR. The genes of the insulin/FoxO1/Pdx1/MafA signaling pathway were first expressed at embryonic day 14 (E14). The expressions of insulin and MafA increased as the fetus grew while the expressions of FoxO1 and Pdx1 decreased. Compared with the control rats, the expressions of FoxO1, Pdx1, and MafA were lower in the IUGR rats, whereas insulin levels showed no change. Microarray profiling, in combination with quantitative real-time PCR, uncovered a subset of microRNAs that changed in their degree of expression throughout pancreatic development. In conclusion, our data support the hypothesis that IUGR influences the development of the rat pancreas. We also identified new pathways that appear to be programmed by IUGR. © 2016 by the Society for Experimental Biology and Medicine.

  19. Rita Historical Page - Office of Satellite and Product Operations

    Science.gov (United States)

    Advisory Archive. Floater Imagery September 24/0015Z to 24/1345Z: Image: AVN | BD | FT | IR | IR2 | JSL | RB | RGB | VIS | WV Image (w/ Latitude & Longitude): AVN | BD | FT | IR | IR2 | JSL | RB | RGB | VIS | WV Loop: AVN | BD | FT | IR | IR2 | JSL | RB | RGB | VIS | WV Gulf Of Mexico Imagery September

  20. Wilma Historical Page - Office of Satellite and Product Operations

    Science.gov (United States)

    Report and Advisory Archive. Floater Imagery October 24/0715Z to 24/1415Z: Image: AVN | BD | FT | IR | IR2 | JSL | RB | RGB | VIS | WV Image (w/ Latitude & Longitude): AVN | BD | FT | IR | IR2 | JSL | RB | RGB | VIS | WV Loop: AVN | BD | FT | IR | IR2 | JSL | RB | RGB | VIS | WV Gulf Of Mexico Imagery

  1. Katrina Historical Page - Office of Satellite and Product Operations

    Science.gov (United States)

    . Floater Imagery August 28/1745Z to 29/0245Z: Image: AVN | BD | FT | IR | IR2 | JSL | RB | RGB | VIS | WV Image (w/ Latitude & Longitude): AVN | BD | FT | IR | IR2 | JSL | RB | RGB | VIS | WV Loop: AVN | BD : AVN | BD | FT | IR | IR2 | JSL | RB | RGB | VIS | WV Image (w/ Latitude & Longitude): AVN | BD

  2. G protein-coupled receptor 39 deficiency is associated with pancreatic islet dysfunction

    DEFF Research Database (Denmark)

    Holst, Birgitte; Egerod, Kristoffer L; Jin, Chunyu

    2009-01-01

    G protein-coupled receptor (GPR)-39 is a seven-transmembrane receptor expressed mainly in endocrine and metabolic tissues that acts as a Zn(++) sensor signaling mainly through the G(q) and G(12/13) pathways. The expression of GPR39 is regulated by hepatocyte nuclear factor (HNF)-1alpha and HNF-4...... tolerance both during oral and iv glucose tolerance tests, and Gpr39(-/-) mice had decreased plasma insulin response to oral glucose. Islet architecture was normal in the Gpr39 null mice, but expression of Pdx-1 and Hnf-1alpha was reduced. Isolated, perifused islets from Gpr39 null mice secreted less...

  3. Genome sequence of a diabetes-prone rodent reveals a mutation hotspot around the ParaHox gene cluster

    DEFF Research Database (Denmark)

    Hargreaves, Adam D.; Zhou, Long; Christensen, Josef

    2017-01-01

    The sand rat Psammomys obesus is a gerbil species native to deserts of North Africa and the Middle East, and is constrained in its ecology because high carbohydrate diets induce obesity and type II diabetes that, in extreme cases, can lead to pancreatic failure and death. We report the sequencing...... Pdx1 has been grossly affected by GC-biased mutation, leading to the highest divergence observed for this gene across the Bilateria. In addition to genomic insights into restricted caloric intake in a desert species, the discovery of a localized chromosomal region subject to elevated mutation suggests...

  4. A hierarchical analysis of transcriptome alterations in intrauterine growth restriction (IUGR) reveals common pathophysiological pathways in mammals.

    Science.gov (United States)

    Buffat, C; Mondon, F; Rigourd, V; Boubred, F; Bessières, B; Fayol, L; Feuerstein, J-M; Gamerre, M; Jammes, H; Rebourcet, R; Miralles, F; Courbières, B; Basire, A; Dignat-Georges, F; Carbonne, B; Simeoni, U; Vaiman, D

    2007-11-01

    Intra-uterine growth restriction (IUGR) is a frequent disease, affecting up to 10% of human pregnancies and responsible for increased perinatal morbidity and mortality. Moreover, low birth weight is an important cause of the metabolic syndrome in the adult. Protein depletion during the gestation of rat females has been widely used as a model for human IUGR. By transcriptome analysis of control and protein-deprived rat placentas, we were able to identify 2543 transcripts modified more than 2.5 fold (1347 induced and 1196 repressed). Automatic functional classification enabled us to identify clusters of induced genes affecting chromosome structure, transcription, intracellular transport, protein modifications and apoptosis. In particular, we suggest the existence of a complex balance regulating apoptosis. Among repressed genes, we noted several groups of genes involved in immunity, signalling and degradation of noxious chemicals. These observations suggest that IUGR placentas have a decreased resistance to external aggression. The promoters of the most induced and most repressed genes were contrasted for their composition in putative transcription factor binding sites. There was an over-representation of Zn finger (ZNF) proteins and Pdx1 (pancreatic and duodenal homeobox protein 1) putative binding sites. Consistently, Pdx1 and a high proportion of ZNF genes were induced at the transcriptional level. A similar analysis of ZNF promoters showed an increased presence of putative binding sites for the Tata box binding protein (Tbp). Consistently again, we showed that the Tbp and TBP-associated factors (Tafs) were up-regulated in IUGR placentas. Also, samples of human IUGR and control placentas showed that human orthologous ZNFs and PDX1 were transcriptionally induced, especially in non-vascular IUGR. Immunohistochemistry revealed increased expression of PDX1 in IUGR human placentas. In conclusion, our approach permitted the proposition of hypotheses on a hierarchy of

  5. REST represses a subset of the pancreatic endocrine differentiation program

    DEFF Research Database (Denmark)

    Martin, David; Kim, Yung-Hae; Sever, Dror

    2015-01-01

    in neurons and in endocrine cells, which is necessary for their normal function. During development, REST represses a subset of genes in the neuronal differentiation program and Rest is down-regulated as neurons differentiate. Here, we investigate the role of REST in the differentiation of pancreatic...... endocrine cells, which are molecularly close to neurons. We show that Rest is widely expressed in pancreas progenitors and that it is down-regulated in differentiated endocrine cells. Sustained expression of REST in Pdx1(+) progenitors impairs the differentiation of endocrine-committed Neurog3...

  6. FDG PET imaging of Ela1-myc mice reveals major biological differences between pancreatic acinar and ductal tumours

    International Nuclear Information System (INIS)

    Abasolo, Ibane; Pujal, Judit; Navarro, Pilar; Rabanal, Rosa M.; Serafin, Anna; Millan, Olga; Real, Francisco X.

    2009-01-01

    The aim was to evaluate FDG PET imaging in Ela1-myc mice, a pancreatic cancer model resulting in the development of tumours with either acinar or mixed acinar-ductal phenotype. Transversal and longitudinal FDG PET studies were conducted; selected tissue samples were subjected to autoradiography and ex vivo organ counting. Glucose transporter and hexokinase mRNA expression was analysed by quantitative reverse transcription polymerase chain reaction (RT-PCR); Glut2 expression was analysed by immunohistochemistry. Transversal studies showed that mixed acinar-ductal tumours could be identified by FDG PET several weeks before they could be detected by hand palpation. Longitudinal studies revealed that ductal - but not acinar - tumours could be detected by FDG PET. Autoradiographic analysis confirmed that tumour areas with ductal differentiation incorporated more FDG than areas displaying acinar differentiation. Ex vivo radioactivity measurements showed that tumours of solely acinar phenotype incorporated more FDG than pancreata of non-transgenic littermates despite the fact that they did not yield positive PET images. To gain insight into the biological basis of the differential FDG uptake, glucose transporter and hexokinase transcript expression was studied in microdissected tumour areas enriched for acinar or ductal cells and validated using cell-specific markers. Glut2 and hexokinase I and II mRNA levels were up to 20-fold higher in ductal than in acinar tumours. Besides, Glut2 protein overexpression was found in ductal neoplastic cells but not in the surrounding stroma. In Ela1-myc mice, ductal tumours incorporate significantly more FDG than acinar tumours. This difference likely results from differential expression of Glut2 and hexokinases. These findings reveal previously unreported biological differences between acinar and ductal pancreatic tumours. (orig.)

  7. Insulin Signaling in Liver and Adipose Tissues in Periparturient Dairy Cows Supplemented with Dietary Nicotinic Acid.

    Science.gov (United States)

    Kinoshita, Asako; Kenéz, Ákos; Locher, Lena; Meyer, Ulrich; Dänicke, Sven; Rehage, Jürgen; Huber, Korinna

    2016-01-01

    The glucose homeostasis in dairy cattle is very well controlled, in line with the metabolic adaptation during the periparturient period. Former studies showed that nicotinic acid (NA) lowered plasma non-esterified fatty acids (NEFA) concentrations and increased insulin sensitivity in dairy cows. Thus, the purpose of this study was to investigate whether the expression of proteins involved in hepatic and adipose insulin signaling and protein expression of hepatic glucose transporter 2 (GLUT2) were affected by dietary NA and dietary concentrate intake in periparturient dairy cows. Twenty pluriparous German Holstein cows were fed with the same diet from about 21 days before the expected calving date (d-21) to calving. After calving, cows were randomly assigned in 4 groups and fed with diets different in concentrate proportion ("HC" with 60:40% or "LC" with 30:70% concentrate-to-roughage ratio) and supplemented with NA (24 g/day) (NA) or without (CON) until d21. Biopsy samples were taken from the liver, subcutaneous (SCAT) and retroperitoneal (RPAT) adipose tissues at d-21 and d21. Protein expression of insulin signaling molecules (insulin receptor (INSR), phosphatidylinositol-3-kinase (PI3K), protein kinase Cζ (PKCζ)) and hepatic GLUT2 was measured by Western Blotting. The ratio of protein expression at d21/at d-21 was calculated and statistically evaluated for the effects of time and diet. Cows in HC had significantly higher dietary energy intake than cows in LC. In RPAT a decrease in PI3K and PKCζ expression was found in all groups, irrespectively of diet. In the liver, the GLUT2 expression was significantly lower in cows in NA compared with cows in CON. In conclusion, insulin signaling might be decreased in RPAT over time without any effect of diet. NA was able to modulate hepatic GLUT2 expression, but its physiological role is unclear.

  8. Insulin Signaling in Liver and Adipose Tissues in Periparturient Dairy Cows Supplemented with Dietary Nicotinic Acid.

    Directory of Open Access Journals (Sweden)

    Asako Kinoshita

    Full Text Available The glucose homeostasis in dairy cattle is very well controlled, in line with the metabolic adaptation during the periparturient period. Former studies showed that nicotinic acid (NA lowered plasma non-esterified fatty acids (NEFA concentrations and increased insulin sensitivity in dairy cows. Thus, the purpose of this study was to investigate whether the expression of proteins involved in hepatic and adipose insulin signaling and protein expression of hepatic glucose transporter 2 (GLUT2 were affected by dietary NA and dietary concentrate intake in periparturient dairy cows. Twenty pluriparous German Holstein cows were fed with the same diet from about 21 days before the expected calving date (d-21 to calving. After calving, cows were randomly assigned in 4 groups and fed with diets different in concentrate proportion ("HC" with 60:40% or "LC" with 30:70% concentrate-to-roughage ratio and supplemented with NA (24 g/day (NA or without (CON until d21. Biopsy samples were taken from the liver, subcutaneous (SCAT and retroperitoneal (RPAT adipose tissues at d-21 and d21. Protein expression of insulin signaling molecules (insulin receptor (INSR, phosphatidylinositol-3-kinase (PI3K, protein kinase Cζ (PKCζ and hepatic GLUT2 was measured by Western Blotting. The ratio of protein expression at d21/at d-21 was calculated and statistically evaluated for the effects of time and diet. Cows in HC had significantly higher dietary energy intake than cows in LC. In RPAT a decrease in PI3K and PKCζ expression was found in all groups, irrespectively of diet. In the liver, the GLUT2 expression was significantly lower in cows in NA compared with cows in CON. In conclusion, insulin signaling might be decreased in RPAT over time without any effect of diet. NA was able to modulate hepatic GLUT2 expression, but its physiological role is unclear.

  9. Effect of high sugar intake on glucose transporter and weight regulating hormones in mice and humans.

    Directory of Open Access Journals (Sweden)

    Yvonne Ritze

    Full Text Available OBJECTIVE: Sugar consumption has increased dramatically over the last decades in Western societies. Especially the intake of sugar-sweetened beverages seems to be a major risk for the development of obesity. Thus, we compared liquid versus solid high-sugar diets with regard to dietary intake, intestinal uptake and metabolic parameters in mice and partly in humans. METHODS: Five iso-caloric diets, enriched with liquid (in water 30% vol/vol or solid (in diet 65% g/g fructose or sucrose or a control diet were fed for eight weeks to C57bl/6 mice. Sugar, liquid and caloric intake, small intestinal sugar transporters (GLUT2/5 and weight regulating hormone mRNA expression, as well as hepatic fat accumulation were measured. In obese versus lean humans that underwent either bariatric surgery or small bowel resection, we analyzed small intestinal GLUT2, GLUT5, and cholecystokinin expression. RESULTS: In mice, the liquid high-sucrose diet caused an enhancement of total caloric intake compared to the solid high-sucrose diet and the control diet. In addition, the liquid high-sucrose diet increased expression of GLUT2, GLUT5, and cholecystokinin expression in the ileum (P<0.001. Enhanced liver triglyceride accumulation was observed in mice being fed the liquid high-sucrose or -fructose, and the solid high-sucrose diet compared to controls. In obese, GLUT2 and GLUT5 mRNA expression was enhanced in comparison to lean individuals. CONCLUSIONS: We show that the form of sugar intake (liquid versus solid is presumably more important than the type of sugar, with regard to feeding behavior, intestinal sugar uptake and liver fat accumulation in mice. Interestingly, in obese individuals, an intestinal sugar transporter modulation also occurred when compared to lean individuals.

  10. FDG PET imaging of Ela1-myc mice reveals major biological differences between pancreatic acinar and ductal tumours

    Energy Technology Data Exchange (ETDEWEB)

    Abasolo, Ibane [Institut Municipal d' Investigacio Medica-Hospital del Mar, Parc de Recerca Biomedica de Barcelona, Barcelona (Spain); Universitat Pompeu Fabra, Parc de Recerca Biomedica de Barcelona, Departament de Ciencies Experimentals i de la Salut, Barcelona (Spain); Institut d' Alta Tecnologia - CRC, Parc de Recerca Biomedica de Barcelona, Barcelona (Spain); Pujal, Judit; Navarro, Pilar [Institut Municipal d' Investigacio Medica-Hospital del Mar, Parc de Recerca Biomedica de Barcelona, Barcelona (Spain); Rabanal, Rosa M.; Serafin, Anna [Universitat Autonoma de Barcelona, Departament de Medicina i Cirurgia Animals, Barcelona (Spain); Millan, Olga [Institut d' Alta Tecnologia - CRC, Parc de Recerca Biomedica de Barcelona, Barcelona (Spain); Real, Francisco X. [Institut Municipal d' Investigacio Medica-Hospital del Mar, Parc de Recerca Biomedica de Barcelona, Barcelona (Spain); Universitat Pompeu Fabra, Parc de Recerca Biomedica de Barcelona, Departament de Ciencies Experimentals i de la Salut, Barcelona (Spain); Programa de Patologia Molecular, Centro Nacional de Investigaciones Oncologicas, Madrid (Spain)

    2009-07-15

    The aim was to evaluate FDG PET imaging in Ela1-myc mice, a pancreatic cancer model resulting in the development of tumours with either acinar or mixed acinar-ductal phenotype. Transversal and longitudinal FDG PET studies were conducted; selected tissue samples were subjected to autoradiography and ex vivo organ counting. Glucose transporter and hexokinase mRNA expression was analysed by quantitative reverse transcription polymerase chain reaction (RT-PCR); Glut2 expression was analysed by immunohistochemistry. Transversal studies showed that mixed acinar-ductal tumours could be identified by FDG PET several weeks before they could be detected by hand palpation. Longitudinal studies revealed that ductal - but not acinar - tumours could be detected by FDG PET. Autoradiographic analysis confirmed that tumour areas with ductal differentiation incorporated more FDG than areas displaying acinar differentiation. Ex vivo radioactivity measurements showed that tumours of solely acinar phenotype incorporated more FDG than pancreata of non-transgenic littermates despite the fact that they did not yield positive PET images. To gain insight into the biological basis of the differential FDG uptake, glucose transporter and hexokinase transcript expression was studied in microdissected tumour areas enriched for acinar or ductal cells and validated using cell-specific markers. Glut2 and hexokinase I and II mRNA levels were up to 20-fold higher in ductal than in acinar tumours. Besides, Glut2 protein overexpression was found in ductal neoplastic cells but not in the surrounding stroma. In Ela1-myc mice, ductal tumours incorporate significantly more FDG than acinar tumours. This difference likely results from differential expression of Glut2 and hexokinases. These findings reveal previously unreported biological differences between acinar and ductal pancreatic tumours. (orig.)

  11. Effects of dietary glucose and sodium chloride on intestinal glucose absorption of common carp (Cyprinus carpio L.).

    Science.gov (United States)

    Qin, Chaobin; Yang, Liping; Zheng, Wenjia; Yan, Xiao; Lu, Ronghua; Xie, Dizhi; Nie, Guoxing

    2018-01-08

    The co-transport of sodium and glucose is the first step for intestinal glucose absorption. Dietary glucose and sodium chloride (NaCl) may facilitate this physiological process in common carp (Cyprinus carpio L.). To test this hypothesis, we first investigated the feeding rhythm of intestinal glucose absorption. Carps were fed to satiety once a day (09:00 a.m.) for 1 month. Intestinal samples were collected at 01:00, 05:00, 09:00, 13:00, 17:00 and 21:00. Result showed that food intake greatly enhanced sodium/glucose cotransporter 1 (SGLT1) and glucose transporter type 2 (GLUT2) expressions, and improved glucose absorption, with highest levels at 09:00 a.m.. Then we designed iso-nitrogenous and iso-energetic diets with graded levels of glucose (10%, 20%, 30%, 40% and 50%) and NaCl (0%, 1%, 3% and 5%), and submitted to feeding trial for 10 weeks. The expressions of SGLT1 and GLUT2, brush border membrane vesicles (BBMVs) glucose transport and intestinal villus height were determined after the feeding trial. Increasing levels of dietary glucose and NaCl up-regulated mRNA and protein levels of SGLT1 and GLUT2, enhanced BBMVs glucose transport in the proximal, mid and distal intestine. As for histological adaptive response, however, high-glucose diet prolonged while high-NaCl diet shrank intestinal villus height. Furthermore, we also found that higher mRNA levels of SGLT1 and GLUT2, higher glucose transport capacity of BBMVs, and higher intestinal villus were detected in the proximal and mid intestine, compared to the distal part. Taken together, our study indicated that intestinal glucose absorption in carp was primarily occurred in the proximal and mid intestine, and increasing levels of dietary glucose and NaCl enhanced intestinal glucose absorption in carp. Copyright © 2017 Elsevier Inc. All rights reserved.

  12. Selective insulin resistance in hepatocyte senescence

    International Nuclear Information System (INIS)

    Aravinthan, Aloysious; Challis, Benjamin; Shannon, Nicholas; Hoare, Matthew; Heaney, Judith; Alexander, Graeme J.M.

    2015-01-01

    Insulin resistance has been described in association with chronic liver disease for decades. Hepatocyte senescence has been demonstrated in chronic liver disease and as many as 80% of hepatocytes show a senescent phenotype in advanced liver disease. The aim of this study was to understand the role of hepatocyte senescence in the development of insulin resistance. Senescence was induced in HepG2 cells via oxidative stress. The insulin metabolic pathway was studied in control and senescent cells following insulin stimulation. GLUT2 and GLUT4 expressions were studied in HepG2 cells and human liver tissue. Further, GLUT2 and GLUT4 expressions were studied in three independent chronic liver disease cohorts. Signalling impairment distal to Akt in phosphorylation of AS160 and FoxO1 was evident in senescent HepG2 cells. Persistent nuclear localisation of FoxO1 was demonstrated in senescent cells despite insulin stimulation. Increased GLUT4 and decreased GLUT2 expressions were evident in senescent cells, human cirrhotic liver tissue and publically available liver disease datasets. Changes in GLUT expressions were associated with a poor clinical prognosis. In conclusion, selective insulin resistance is evident in senescent HepG2 cells and changes in GLUT expressions can be used as surrogate markers of hepatocyte senescence. - Highlights: • Senescent hepatocytes demonstrate selective insulin resistance. • GLUT changes act as markers of hepatocyte senescence and have prognostic value. • Study offers insight into long noticed intimacy of cirrhosis and insulin resistance

  13. Selective insulin resistance in hepatocyte senescence

    Energy Technology Data Exchange (ETDEWEB)

    Aravinthan, Aloysious [Division of Gastroenterology and Hepatology, Department of Medicine, University of Cambridge, Cambridge (United Kingdom); Challis, Benjamin [Institute of Metabolic Sciences, University of Cambridge, Cambridge (United Kingdom); Shannon, Nicholas [Cancer Research UK Cambridge Institute, Cambridge (United Kingdom); Hoare, Matthew [Division of Gastroenterology and Hepatology, Department of Medicine, University of Cambridge, Cambridge (United Kingdom); Cancer Research UK Cambridge Institute, Cambridge (United Kingdom); Heaney, Judith [Division of Gastroenterology and Hepatology, Department of Medicine, University of Cambridge, Cambridge (United Kingdom); Foundation for Liver Research, Institute of Hepatology, London (United Kingdom); Alexander, Graeme J.M., E-mail: gja1000@doctors.org.uk [Division of Gastroenterology and Hepatology, Department of Medicine, University of Cambridge, Cambridge (United Kingdom)

    2015-02-01

    Insulin resistance has been described in association with chronic liver disease for decades. Hepatocyte senescence has been demonstrated in chronic liver disease and as many as 80% of hepatocytes show a senescent phenotype in advanced liver disease. The aim of this study was to understand the role of hepatocyte senescence in the development of insulin resistance. Senescence was induced in HepG2 cells via oxidative stress. The insulin metabolic pathway was studied in control and senescent cells following insulin stimulation. GLUT2 and GLUT4 expressions were studied in HepG2 cells and human liver tissue. Further, GLUT2 and GLUT4 expressions were studied in three independent chronic liver disease cohorts. Signalling impairment distal to Akt in phosphorylation of AS160 and FoxO1 was evident in senescent HepG2 cells. Persistent nuclear localisation of FoxO1 was demonstrated in senescent cells despite insulin stimulation. Increased GLUT4 and decreased GLUT2 expressions were evident in senescent cells, human cirrhotic liver tissue and publically available liver disease datasets. Changes in GLUT expressions were associated with a poor clinical prognosis. In conclusion, selective insulin resistance is evident in senescent HepG2 cells and changes in GLUT expressions can be used as surrogate markers of hepatocyte senescence. - Highlights: • Senescent hepatocytes demonstrate selective insulin resistance. • GLUT changes act as markers of hepatocyte senescence and have prognostic value. • Study offers insight into long noticed intimacy of cirrhosis and insulin resistance.

  14. Renal denervation in an animal model of diabetes and hypertension: Impact on the autonomic nervous system and nephropathy

    Directory of Open Access Journals (Sweden)

    Machado Ubiratan F

    2011-04-01

    Full Text Available Abstract Background The effects of renal denervation on cardiovascular reflexes and markers of nephropathy in diabetic-hypertensive rats have not yet been explored. Methods Aim: To evaluate the effects of renal denervation on nephropathy development mechanisms (blood pressure, cardiovascular autonomic changes, renal GLUT2 in diabetic-hypertensive rats. Forty-one male spontaneously hypertensive rats (SHR ~250 g were injected with STZ or not; 30 days later, surgical renal denervation (RD or sham procedure was performed; 15 days later, glycemia and albuminuria (ELISA were evaluated. Catheters were implanted into the femoral artery to evaluate arterial pressure (AP and heart rate variability (spectral analysis one day later in conscious animals. Animals were killed, kidneys removed, and cortical renal GLUT2 quantified (Western blotting. Results Higher glycemia (p vs. nondiabetics (p vs. SHR. Conclusions Renal denervation in diabetic-hypertensive rats improved previously reduced heart rate variability. The GLUT2 equally overexpressed by diabetes and renal denervation may represent a maximal derangement effect of each condition.

  15. The role of fructose transporters in diseases linked to excessive fructose intake

    Science.gov (United States)

    Douard, Veronique; Ferraris, Ronaldo P

    2013-01-01

    Fructose intake has increased dramatically since humans were hunter-gatherers, probably outpacing the capacity of human evolution to make physiologically healthy adaptations. Epidemiological data indicate that this increasing trend continued until recently. Excessive intakes that chronically increase portal and peripheral blood fructose concentrations to >1 and 0.1 mm, respectively, are now associated with numerous diseases and syndromes. The role of the fructose transporters GLUT5 and GLUT2 in causing, contributing to or exacerbating these diseases is not well known. GLUT5 expression seems extremely low in neonatal intestines, and limited absorptive capacities for fructose may explain the high incidence of malabsorption in infants and cause problems in adults unable to upregulate GLUT5 levels to match fructose concentrations in the diet. GLUT5- and GLUT2-mediated fructose effects on intestinal electrolyte transporters, hepatic uric acid metabolism, as well as renal and cardiomyocyte function, may play a role in fructose-induced hypertension. Likewise, GLUT2 may contribute to the development of non-alcoholic fatty liver disease by facilitating the uptake of fructose. Finally, GLUT5 may play a role in the atypical growth of certain cancers and fat tissues. We also highlight research areas that should yield information needed to better understand the role of these GLUTs in fructose-induced diseases. PMID:23129794

  16. Plasticity of adult human pancreatic duct cells by neurogenin3-mediated reprogramming.

    Directory of Open Access Journals (Sweden)

    Nathalie Swales

    Full Text Available AIMS/HYPOTHESIS: Duct cells isolated from adult human pancreas can be reprogrammed to express islet beta cell genes by adenoviral transduction of the developmental transcription factor neurogenin3 (Ngn3. In this study we aimed to fully characterize the extent of this reprogramming and intended to improve it. METHODS: The extent of the Ngn3-mediated duct-to-endocrine cell reprogramming was measured employing genome wide mRNA profiling. By modulation of the Delta-Notch signaling or addition of pancreatic endocrine transcription factors Myt1, MafA and Pdx1 we intended to improve the reprogramming. RESULTS: Ngn3 stimulates duct cells to express a focused set of genes that are characteristic for islet endocrine cells and/or neural tissues. This neuro-endocrine shift however, is incomplete with less than 10% of full duct-to-endocrine reprogramming achieved. Transduction of exogenous Ngn3 activates endogenous Ngn3 suggesting auto-activation of this gene. Furthermore, pancreatic endocrine reprogramming of human duct cells can be moderately enhanced by inhibition of Delta-Notch signaling as well as by co-expressing the transcription factor Myt1, but not MafA and Pdx1. CONCLUSIONS/INTERPRETATION: The results provide further insight into the plasticity of adult human duct cells and suggest measurable routes to enhance Ngn3-mediated in vitro reprogramming protocols for regenerative beta cell therapy in diabetes.

  17. [Culture of pancreatic progenitor cells in hanging drop and on floating filter].

    Science.gov (United States)

    Ma, Feng-xia; Chen, Fang; Chi, Ying; Yang, Shao-guang; Lu, Shi-hong; Han, Zhong-chao

    2013-06-01

    To construct a method to culture pancreatic progenitor cells in hanging drop and on floating filter,and to examine if pancreatic progenitor cells can differentiate into mature endocrine cells with this method. Murine embryos at day 12.5 were isolated and digested into single cells,which were then cultured in hanging drop for 24h and formed spheres.Spheres were cultured on the filter for 6 days,which floated in the dish containing medium.During culture,the expressions of pancreas duodenum homeobox-1(PDX-1)and neurogenin3(Ngn3)were determined.The expressions of endocrine and exocrine markers,insulin,glucagon,and carboxypeptidase(CPA)were determined on day 7 by immunohistochemistry.Insulin secretion of spheres stimulated by glucose was detected by ELISA.The changes of pancreatic marker expressions during culture were monitored by real-time polymerase chain reaction(PCR). One day after the culture,there were still a large amount of PDX-1 positive cells in pancreatic spheres,and these cells proliferated.On day 3,high expression of Ngn3 was detected,and the Ngn3-positive cells did not proliferate.On day 7,The expressions of endocrine and exocrine markers in the differentiated pancreatic progenitor cells were detected,which were consistent with that in vivo.Insulin was secreted by spheres upon the stimulation of glucose. In hanging drop and on floating filter,pancreatic progenitor cells can differentiate into mature endocrine cells.

  18. Genetically Targeted Dipeptidyl Peptidase-4 Inhibitor Use in a Patient with a Novel Mutation of MODY type 4

    Directory of Open Access Journals (Sweden)

    Christian Mangrum

    2015-01-01

    Full Text Available Maturity onset diabetes of the young (MODY is a rare form of diabetes mellitus typically seen in young adults that results from pancreatic beta-cell dysfunction. MODY4 is a rare subtype caused by a PDX1 mutation. In this case, we present a nonobese 26-year-old male with polyuria and polydipsia. Lab work showed a blood glucose of 511 mg/dL, no ketones or antibodies (insulin, islet cell, and glutamic acid decarboxylase [GAD], C-peptide of 1.6 ng/mL, and A1c 9.3%. Genetic analysis revealed a novel nonsense mutation in the PDX1 gene, consistent with MODY type 4. Given this patient's particular genetic mutation affecting the incretin pathway, sitagliptin was substituted for glyburide, which led to significant improvement in glycemic control. Our case report identifies a unique mutation in a rare form of MODY and outlines management of ensuing diabetes through targeting its inherent genetic mutation.

  19. Reversal of hyperglycemia in mice by using human expandable insulin-producing cells differentiated from fetal liver progenitor cells

    Science.gov (United States)

    Zalzman, Michal; Gupta, Sanjeev; Giri, Ranjit K.; Berkovich, Irina; Sappal, Baljit S.; Karnieli, Ohad; Zern, Mark A.; Fleischer, Norman; Efrat, Shimon

    2003-06-01

    Beta-cell replacement is considered to be the most promising approach for treatment of type 1 diabetes. Its application on a large scale is hindered by a shortage of cells for transplantation. Activation of insulin expression, storage, and regulated secretion in stem/progenitor cells offers novel ways to overcome this shortage. We explored whether fetal human progenitor liver cells (FH) could be induced to differentiate into insulin-producing cells after expression of the pancreatic duodenal homeobox 1 (Pdx1) gene, which is a key regulator of pancreatic development and insulin expression in beta cells. FH cells possess a considerable replication capacity, and this was further extended by introduction of the gene for the catalytic subunit of human telomerase. Immortalized FH cells expressing Pdx1 activated multiple beta-cell genes, produced and stored considerable amounts of insulin, and released insulin in a regulated manner in response to glucose. When transplanted into hyperglycemic immunodeficient mice, the cells restored and maintained euglycemia for prolonged periods. Quantitation of human C-peptide in the mouse serum confirmed that the glycemia was normalized by the transplanted human cells. This approach offers the potential of a novel source of cells for transplantation into patients with type 1 diabetes.

  20. In vitro reprogramming of rat bmMSCs into pancreatic endocrine-like cells.

    Science.gov (United States)

    Li, Hong-Tu; Jiang, Fang-Xu; Shi, Ping; Zhang, Tao; Liu, Xiao-Yu; Lin, Xue-Wen; San, Zhong-Yan; Pang, Xi-Ning

    2017-02-01

    Islet transplantation provides curative treatments to patients with type 1 diabetes, but donor shortage restricts the broad use of this therapy. Thus, generation of alternative transplantable cell sources is intensively investigated worldwide. We previously showed that bone marrow-derived mesenchymal stem cells (bmMSCs) can be reprogrammed to pancreatic-like cells through simultaneously forced suppression of Rest/Nrsf (repressor element-1 silencing transcription factor/neuronal restrictive silencing factor) and Shh (sonic hedgehog) and activation of Pdx1 (pancreas and duodenal transcription factor 1). We here aimed to reprogram bmMSCs further along the developmental pathway towards the islet lineages by improving our previous strategy and by overexpression of Ngn3 (neurogenin 3) and NeuroD1 (neurogenic differentiation 1), critical regulators of the development of endocrine pancreas. We showed that compared to the previous protocol, the overexpression of only Pdx1 and Ngn3 reprogrammed bmMSCs into cells with more characteristics of islet endocrine lineages verified with bioinformatic analyses of our RNA-Seq datasets. These analyses indicated 2325 differentially expressed genes including those involved in the pancreas and islet development. We validated with qRT-PCR analysis selective genes identified from the RNA-Seq datasets. Thus, we reprogrammed bmMSCs into islet endocrine-like cells and advanced the endeavor to generate surrogate functional insulin-secreting cells.

  1. Culture of hESC-derived pancreatic progenitors in alginate-based scaffolds.

    Science.gov (United States)

    Formo, Kjetil; Cho, Candy H-H; Vallier, Ludovic; Strand, Berit L

    2015-12-01

    The effect of alginate-based scaffolds with added basement membrane proteins on the in vitro development of hESC-derived pancreatic progenitors was investigated. Cell clusters were encapsulated in scaffolds containing the basement membrane proteins collagen IV, laminin, fibronectin, or extracellular matrix-derived peptides, and maintained in culture for up to 46 days. The cells remained viable throughout the experiment with no signs of central necrosis. Whereas nonencapsulated cells aggregated into larger clusters, some of which showed signs of morphological changes and tissue organization, the alginate matrix stabilized the cluster size and displayed more homogeneous cell morphologies, allowing culture for long periods of time. For all conditions tested, a stable or declining expression of insulin and PDX1 and an increase in glucagon and somatostatin over time indicated a progressive reduction in beta cell-related gene expression. Alginate scaffolds can provide a chemically defined, xeno-free and easily scalable alternative for culture of pancreatic progenitors. Although no increase in insulin and PDX1 gene expression after alginate-immobilized cell culture was seen in this study, further optimization of the matrix physicochemical and biological properties and of the medium composition may still be a relevant strategy to promote the stabilization or maturation of stem cell-derived beta cells. © 2015 Wiley Periodicals, Inc.

  2. Multiple Roles for UV RESISTANCE LOCUS8 in Regulating Gene Expression and Metabolite Accumulation in Arabidopsis under Solar Ultraviolet Radiation1[W][OA

    Science.gov (United States)

    Morales, Luis O.; Brosché, Mikael; Vainonen, Julia; Jenkins, Gareth I.; Wargent, Jason J.; Sipari, Nina; Strid, Åke; Lindfors, Anders V.; Tegelberg, Riitta; Aphalo, Pedro J.

    2013-01-01

    Photomorphogenic responses triggered by low fluence rates of ultraviolet B radiation (UV-B; 280–315 nm) are mediated by the UV-B photoreceptor UV RESISTANCE LOCUS8 (UVR8). Beyond our understanding of the molecular mechanisms of UV-B perception by UVR8, there is still limited information on how the UVR8 pathway functions under natural sunlight. Here, wild-type Arabidopsis (Arabidopsis thaliana) and the uvr8-2 mutant were used in an experiment outdoors where UV-A (315–400 nm) and UV-B irradiances were attenuated using plastic films. Gene expression, PYRIDOXINE BIOSYNTHESIS1 (PDX1) accumulation, and leaf metabolite signatures were analyzed. The results show that UVR8 is required for transcript accumulation of genes involved in UV protection, oxidative stress, hormone signal transduction, and defense against herbivores under solar UV. Under natural UV-A irradiance, UVR8 is likely to interact with UV-A/blue light signaling pathways to moderate UV-B-driven transcript and PDX1 accumulation. UVR8 both positively and negatively affects UV-A-regulated gene expression and metabolite accumulation but is required for the UV-B induction of phenolics. Moreover, UVR8-dependent UV-B acclimation during the early stages of plant development may enhance normal growth under long-term exposure to solar UV. PMID:23250626

  3. Transplantation of bone marrow derived cells promotes pancreatic islet repair in diabetic mice

    International Nuclear Information System (INIS)

    Gao Xiaodong; Song Lujun; Shen Kuntang; Wang Hongshan; Niu Weixin; Qin Xinyu

    2008-01-01

    The transplantation of bone marrow (BM) derived cells to initiate pancreatic regeneration is an attractive but as-yet unrealized strategy. Presently, BM derived cells from green fluorescent protein transgenic mice were transplanted into diabetic mice. Repair of diabetic islets was evidenced by reduction of hyperglycemia, increase in number of islets, and altered pancreatic histology. Cells in the pancreata of recipient mice co-expressed BrdU and insulin. Double staining revealed β cells were in the process of proliferation. BrdU + insulin - PDX-1 + cells, Ngn3 + cells and insulin + glucagon + cells, which showed stem cells, were also found during β-cell regeneration. The majority of transplanted cells were mobilized to the islet and ductal regions. In recipient pancreas, transplanted cells simultaneously expressed CD34 but did not express insulin, PDX-1, Ngn3, Nkx2.2, Nkx6.1, Pax4, Pax6, and CD45. It is concluded that BM derived cells especially CD34 + cells can promote repair of pancreatic islets. Moreover, both proliferation of β cells and differentiation of pancreatic stem cells contribute to the regeneration of β cells

  4. The small intestinal epithelia of beef steers differentially express sugar transporter messenger ribonucleic acid in response to abomasal versus ruminal infusion of starch hydrolysate.

    Science.gov (United States)

    Liao, S F; Harmon, D L; Vanzant, E S; McLeod, K R; Boling, J A; Matthews, J C

    2010-01-01

    In mammals, the absorption of monosaccharides from small intestinal lumen involves at least 3 sugar transporters (SugT): sodium-dependent glucose transporter 1 (SGLT1; gene SLC5A1) transports glucose and galactose, whereas glucose transporter (GLUT) 5 (GLUT5; gene SLC2A5) transports fructose, across the apical membrane of enterocytes. In contrast, GLUT2 (gene SLC2A2) transports all of these sugars across basolateral and apical membranes. To compare the distribution patterns and sensitivity with nutritional regulation of these 3 SugT mRNA in beef cattle small intestinal tissue, 18 ruminally and abomasally catheterized Angus steers (BW approximately 260 kg) were assigned to water (control), ruminal cornstarch (partially hydrolyzed by alpha-amylase; SH), or abomasal SH infusion treatments (n = 6) and fed an alfalfa-cube-based diet at 1.3 x NE(m) requirement. The SH infusions amounted to 20% of ME intake. After 14- or 16-d of infusion, steers were killed; duodenal, jejunal, and ileal epithelia harvested; and total RNA extracted. The relative amount of SugT mRNA in epithelia was determined using real-time reverse transcription-PCR quantification methods. Basal expression of GLUT2 and SGLT1 mRNA was greater (P content of GLUT5 mRNA was greater (P content of GLUT5 mRNA in small intestinal epithelia was not affected (P > or = 0.16) by either SH infusion treatment. In contrast, GLUT2 and SGLT1 mRNA content in the ileal epithelium was increased (P content also was increased (P = 0.07) by 64% after ruminal SH infusion. These results demonstrate that the ileum of beef cattle small intestine adapts to an increased luminal supply of glucose by increasing SGLT1 and GLUT2 mRNA content, whereas increased ruminal SH supply results in duodenal upregulation of SGLT1 mRNA content. These adaptive responses of GLUT2 and SGLT1 mRNA to abomasal or ruminal SH infusion suggest that beef cattle can adapt to increase their carbohydrate assimilation through small intestinal epithelia, assuming

  5. Histone deacetylase regulates insulin signaling via two pathways in pancreatic β cells.

    Directory of Open Access Journals (Sweden)

    Yukina Kawada

    Full Text Available Recent studies demonstrated that insulin signaling plays important roles in the regulation of pancreatic β cell mass, the reduction of which is known to be involved in the development of diabetes. However, the mechanism underlying the alteration of insulin signaling in pancreatic β cells remains unclear. The involvement of epigenetic control in the onset of diabetes has also been reported. Thus, we analyzed the epigenetic control of insulin receptor substrate 2 (IRS2 expression in the MIN6 mouse insulinoma cell line. We found concomitant IRS2 up-regulation and enhanced insulin signaling in MIN6 cells, which resulted in an increase in cell proliferation. The H3K9 acetylation status of the Irs2 promoter was positively associated with IRS2 expression. Treatment of MIN6 cells with histone deacetylase inhibitors led to increased IRS2 expression, but this occurred in concert with low insulin signaling. We observed increased IRS2 lysine acetylation as a consequence of histone deacetylase inhibition, a modification that was coupled with a decrease in IRS2 tyrosine phosphorylation. These results suggest that insulin signaling in pancreatic β cells is regulated by histone deacetylases through two novel pathways affecting IRS2: the epigenetic control of IRS2 expression by H3K9 promoter acetylation, and the regulation of IRS2 activity through protein modification. The identification of the histone deacetylase isoform(s involved in these mechanisms would be a valuable approach for the treatment of type 2 diabetes.

  6. A designated centre for people with disabilities operated by Brothers of Charity Services Roscommon

    LENUS (Irish Health Repository)

    Carew, Rosemarie M.

    2010-07-06

    Abstract Background Male Irs2-\\/- mice develop fatal type 2 diabetes at 13-14 weeks. Defects in neuronal proliferation, pituitary development and photoreceptor cell survival manifest in Irs2-\\/- mice. We identify retarded renal growth in male and female Irs2-\\/- mice, independent of diabetes. Results Kidney size and kidney:body weight ratio were reduced by approximately 20% in Irs2-\\/- mice at postnatal day 5 and was maintained in maturity. Reduced glomerular number but similar glomerular density was detected in Irs2-\\/- kidney compared to wild-type, suggesting intact global kidney structure. Analysis of insulin signalling revealed renal-specific upregulation of PKBβ\\/Akt2, hyperphosphorylation of GSK3β and concomitant accumulation of β-catenin in Irs2-\\/- kidney. Despite this, no significant upregulation of β-catenin targets was detected. Kidney-specific increases in Yes-associated protein (YAP), a key driver of organ size were also detected in the absence of Irs2. YAP phosphorylation on its inhibitory site Ser127 was also increased, with no change in the levels of YAP-regulated genes, suggesting that overall YAP activity was not increased in Irs2-\\/- kidney. Conclusions In summary, deletion of Irs2 causes reduced kidney size early in mouse development. Compensatory mechanisms such as increased β-catenin and YAP levels failed to overcome this developmental defect. These data point to Irs2 as an important novel mediator of kidney size.

  7. Growth hormone, interferon-gamma, and leukemia inhibitory factor utilize insulin receptor substrate-2 in intracellular signaling

    DEFF Research Database (Denmark)

    Argetsinger, L S; Norstedt, G; Billestrup, Nils

    1996-01-01

    In this report, we demonstrate that insulin receptor substrate-2 (IRS-2) is tyrosyl-phosphorylated following stimulation of 3T3-F442A fibroblasts with growth hormone (GH), leukemia inhibitory factor and interferon-gamma. In response to GH and leukemia inhibitory factor, IRS-2 is immediately...... for GH is further demonstrated by the finding that GH stimulates association of IRS-2 with the 85-kDa regulatory subunit of phosphatidylinositol 3'-kinase and with the protein-tyrosine phosphatase SHP2. These results are consistent with the possibility that IRS-2 is a downstream signaling partner...

  8. Regeneration of pancreatic non-β endocrine cells in adult mice following a single diabetes-inducing dose of streptozotocin.

    Directory of Open Access Journals (Sweden)

    Yanqing Zhang

    Full Text Available The non-β endocrine cells in pancreatic islets play an essential counterpart and regulatory role to the insulin-producing β-cells in the regulation of blood-glucose homeostasis. While significant progress has been made towards the understanding of β-cell regeneration in adults, very little is known about the regeneration of the non-β endocrine cells such as glucagon-producing α-cells and somatostatin producing δ-cells. Previous studies have noted the increase of α-cell composition in diabetes patients and in animal models. It is thus our hypothesis that non-β-cells such as α-cells and δ-cells in adults can regenerate, and that the regeneration accelerates in diabetic conditions. To test this hypothesis, we examined islet cell composition in a streptozotocin (STZ-induced diabetes mouse model in detail. Our data showed the number of α-cells in each islet increased following STZ-mediated β-cell destruction, peaked at Day 6, which was about 3 times that of normal islets. In addition, we found δ-cell numbers doubled by Day 6 following STZ treatment. These data suggest α- and δ-cell regeneration occurred rapidly following a single diabetes-inducing dose of STZ in mice. Using in vivo BrdU labeling techniques, we demonstrated α- and δ-cell regeneration involved cell proliferation. Co-staining of the islets with the proliferating cell marker Ki67 showed α- and δ-cells could replicate, suggesting self-duplication played a role in their regeneration. Furthermore, Pdx1(+/Insulin(- cells were detected following STZ treatment, indicating the involvement of endocrine progenitor cells in the regeneration of these non-β cells. This is further confirmed by the detection of Pdx1(+/glucagon(+ cells and Pdx1(+/somatostatin(+ cells following STZ treatment. Taken together, our study demonstrated adult α- and δ-cells could regenerate, and both self-duplication and regeneration from endocrine precursor cells were involved in their regeneration.

  9. Do we really need to differentiate mesenchymal stem cells into insulin-producing cells for attenuation of the autoimmune responses in type 1 diabetes: immunoprophylactic effects of precursors to insulin-producing cells.

    Science.gov (United States)

    Sharma, Anshu; Rani, Rajni

    2017-07-12

    Type 1 diabetes (T1D) is a multifactorial autoimmune disorder where pancreatic beta cells are lost before the clinical manifestations of the disease. Administration of mesenchymal stem cells (MSCs) or MSCs differentiated into insulin-producing cells (IPCs) have yielded limited success when used therapeutically. We have evaluated the immunoprophylactic potentials of precursors to insulin-producing cells (pIPCs) and IPCs in nonobese diabetic (NOD) mice to ask a basic question: do we need to differentiate MSCs into IPCs or will pIPCs suffice to attenuate autoimmune responses in T1D? Bone marrow-derived MSCs from Balb/c mice were characterized following the International Society for Cellular Therapy (ISCT) guidelines. MSCs cultured in high-glucose media for 11 to 13 passages were characterized for the expression of pancreatic lineage genes using real-time polymerase chain reaction. Expression of the PDX1 gene in pIPCs was assessed using Western blot and fluorescence-activated cell sorting (FACS). Triple-positive MSCs were differentiated into IPCs using a three-step protocol after sorting them for cell surface markers, i.e. CD29, CD44, and SCA-1. Nonobese diabetic mice were administered pIPCs, IPCs, or phosphate-buffered saline (PBS) into the tail vein at weeks 9 or 10 and followed-up for 29-30 weeks for fasting blood glucose levels. Two consecutive blood sugar levels of more than 250 mg/dl were considered diabetic. MSCs grown in high-glucose media for 11 to 13 passages expressed genes of the pancreatic lineage such as PDX1, beta2, neurogenin, PAX4, Insulin, and glucagon. Furthermore, Western blot and FACS analysis for PDX-1, a transcription factor necessary for beta cell maturation, confirmed that these cells were precursors of insulin-producing cells (pIPCs). NOD mice administered with pIPCs were better protected from developing diabetes with a protective efficacy of 78.4% (p cells seem to have better potential to arrest autoimmune response in type 1 diabetes when

  10. Insulin-Producing Endocrine Cells Differentiated In Vitro From Human Embryonic Stem Cells Function in Macroencapsulation Devices In Vivo.

    Science.gov (United States)

    Agulnick, Alan D; Ambruzs, Dana M; Moorman, Mark A; Bhoumik, Anindita; Cesario, Rosemary M; Payne, Janice K; Kelly, Jonathan R; Haakmeester, Carl; Srijemac, Robert; Wilson, Alistair Z; Kerr, Justin; Frazier, Mauro A; Kroon, Evert J; D'Amour, Kevin A

    2015-10-01

    The PEC-01 cell population, differentiated from human embryonic stem cells (hESCs), contains pancreatic progenitors (PPs) that, when loaded into macroencapsulation devices (to produce the VC-01 candidate product) and transplanted into mice, can mature into glucose-responsive insulin-secreting cells and other pancreatic endocrine cells involved in glucose metabolism. We modified the protocol for making PEC-01 cells such that 73%-80% of the cell population consisted of PDX1-positive (PDX1+) and NKX6.1+ PPs. The PPs were further differentiated to islet-like cells (ICs) that reproducibly contained 73%-89% endocrine cells, of which approximately 40%-50% expressed insulin. A large fraction of these insulin-positive cells were single hormone-positive and expressed the transcription factors PDX1 and NKX6.1. To preclude a significant contribution of progenitors to the in vivo function of ICs, we used a simple enrichment process to remove remaining PPs, yielding aggregates that contained 93%-98% endocrine cells and 1%-3% progenitors. Enriched ICs, when encapsulated and implanted into mice, functioned similarly to the VC-01 candidate product, demonstrating conclusively that in vitro-produced hESC-derived insulin-producing cells can mature and function in vivo in devices. A scaled version of our suspension culture was used, and the endocrine aggregates could be cryopreserved and retain functionality. Although ICs expressed multiple important β cell genes, the cells contained relatively low levels of several maturity-associated markers. Correlating with this, the time to function of ICs was similar to PEC-01 cells, indicating that ICs required cell-autonomous maturation after delivery in vivo, which would occur concurrently with graft integration into the host. Type 1 diabetes (T1D) affects approximately 1.25 million people in the U.S. alone and is deadly if not managed with insulin injections. This paper describes the production of insulin-producing cells in vitro and a new

  11. Identification and Functional Characterization of P159L Mutation in in a Family with Maturity-Onset Diabetes of the Young 5 (MODY5

    Directory of Open Access Journals (Sweden)

    Eun Ky Kim

    2014-12-01

    Full Text Available Mutation in HNF1B, the hepatocyte nuclear factor-1β (HNF-1β gene, results in maturity-onset diabetes of the young (MODY 5, which is characterized by gradual impairment of insulin secretion. However, the functional role of HNF-1β in insulin secretion and glucose metabolism is not fully understood. We identified a family with early-onset diabetes that fulfilled the criteria of MODY. Sanger sequencing revealed that a heterozygous P159L (CCT to CTT in codon 159 in the DNA-binding domain mutation in HNF1B was segregated according to the affected status. To investigate the functional consequences of this HNF1B mutation, we generated a P159L HNF1B construct. The wild-type and mutant HNF1B constructs were transfected into COS-7 cells in the presence of the promoter sequence of human glucose transporter type 2 (GLUT2. The luciferase reporter assay revealed that P159L HNF1B had decreased transcriptional activity compared to wild-type (p < 0.05. Electrophoretic mobility shift assay showed reduced DNA binding activity of P159L HNF1B. In the MIN6 pancreatic β-cell line, overexpression of the P159L mutant was significantly associated with decreased mRNA levels of GLUT2 compared to wild-type (p < 0.05. However, INS expression was not different between the wild-type and mutant HNF1B constructs. These findings suggests that the impaired insulin secretion in this family with the P159L HNF1B mutation may be related to altered GLUT2 expression in β-cells rather than decreased insulin gene expression. In conclusion, we have identified a Korean family with an HNF1B mutation and characterized its effect on the pathogenesis of diabetes.

  12. Antioxidant effect of mogrosides against oxidative stress induced by palmitic acid in mouse insulinoma NIT-1 cells

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Q.; Chen, S.Y.; Deng, L.D.; Feng, L.P.; Huang, L.Z.; Yu, R.R. [Department of Pharmacy, Guilin Medical University, Guilin (China)

    2013-11-18

    Excessive oxidative stress in pancreatic β cells, caused by glucose and fatty acids, is associated with the pathogenesis of type 2 diabetes. Mogrosides have shown antioxidant and antidiabetic activities in animal models of diabetes, but the underlying mechanisms remain unclear. This study evaluated the antioxidant effect of mogrosides on insulinoma cells under oxidative stress caused by palmitic acid, and investigated the underlying molecular mechanisms. Mouse insulinoma NIT-1 cells were cultured in medium containing 0.75 mM palmitic acid, mimicking oxidative stress. The effects of 1 mM mogrosides were determined with the dichlorodihydrofluorescein diacetate assay for intracellular reactive oxygen species (ROS) and FITC-Annexin V/PI assay for cell apoptosis. Expression of glucose transporter-2 (GLUT2) and pyruvate kinase was determined by semi-quantitative reverse-transcription polymerase chain reaction. Palmitic acid significantly increased intracellular ROS concentration 2-fold (P<0.05), and decreased expression of GLUT2 (by 60%, P<0.05) and pyruvate kinase (by 80%, P<0.05) mRNAs in NIT-1 cells. Compared with palmitic acid, co-treatment with 1 mM mogrosides for 48 h significantly reduced intracellular ROS concentration and restored mRNA expression levels of GLUT2 and pyruvate kinase. However, mogrosides did not reverse palmitic acid-induced apoptosis in NIT-1 cells. Our results indicate that mogrosides might exert their antioxidant effect by reducing intracellular ROS and regulating expression of genes involved in glucose metabolism. Further research is needed to achieve a better understanding of the signaling pathway involved in the antioxidant effect of mogrosides.

  13. Glucose transporters are expressed in taste receptor cells.

    Science.gov (United States)

    Merigo, Flavia; Benati, Donatella; Cristofoletti, Mirko; Osculati, Francesco; Sbarbati, Andrea

    2011-08-01

    In the intestine, changes of sugar concentration generated in the lumen during digestion induce adaptive responses of glucose transporters in the epithelium. A close matching between the intestinal expression of glucose transporters and the composition and amount of the diet has been provided by several experiments. Functional evidence has demonstrated that the regulation of glucose transporters into enterocytes is induced by the sensing of sugar of the enteroendocrine cells through activation of sweet taste receptors (T1R2 and T1R3) and their associated elements of G-protein-linked signaling pathways (e.g. α-gustducin, phospholipase C β type 2 and transient receptor potential channel M5), which are signaling molecules also involved in the perception of sweet substances in the taste receptor cells (TRCs) of the tongue. Considering this phenotypical similarity between the intestinal cells and TRCs, we evaluated whether the TRCs themselves possess proteins of the glucose transport mechanism. Therefore, we investigated the expression of the typical intestinal glucose transporters (i.e. GLUT2, GLUT5 and SGLT1) in rat circumvallate papillae, using immunohistochemistry, double-labeling immunofluorescence, immunoelectron microscopy and reverse transcriptase-polymerase chain reaction analysis. The results showed that GLUT2, GLUT5 and SGLT1 are expressed in TRCs; their immunoreactivity was also observed in cells that displayed staining for α-gustducin and T1R3 receptor. The immunoelectron microscopic results confirmed that GLUT2, GLUT5 and SGLT1 were predominantly expressed in cells with ultrastructural characteristics of chemoreceptor cells. The presence of glucose transporters in TRCs adds a further link between chemosensory information and cellular responses to sweet stimuli that may have important roles in glucose homeostasis, contributing to a better understanding of the pathways implicated in glucose metabolism. © 2011 The Authors. Journal of Anatomy © 2011

  14. Protein Markers of Neurotransmitter Synthesis and Release in Postmortem Schizophrenia Substantia Nigra.

    Science.gov (United States)

    Schoonover, Kirsten E; McCollum, Lesley A; Roberts, Rosalinda C

    2017-01-01

    The substantia nigra (SN) provides the largest dopaminergic input to the brain, projects to the striatum (the primary locus of action for antipsychotic medication), and receives GABAergic and glutamatergic inputs. This study used western blot analysis to compare protein levels of tyrosine hydroxylase (TH), glutamate decarboxylase (GAD67), and vesicular glutamate transporters (vGLUT1 and vGLUT2) in postmortem human SN in schizophrenia subjects (n=13) and matched controls (n=12). As a preliminary analysis, the schizophrenia group was subdivided by (1) treatment status: off medication (n=4) or on medication (n=9); or (2) treatment response: treatment resistant (n=5) or treatment responsive (n=4). The combined schizophrenia group had higher TH and GAD67 protein levels than controls (an increase of 69.6%, P=0.01 and 19.5%, P=0.004, respectively). When subdivided by medication status, these increases were found in the on-medication subjects (TH 88.3%, P=0.008; GAD67 40.6%, P=0.003). In contrast, unmedicated schizophrenia subjects had higher vGLUT2 levels than controls (an increase of 28.7%, P=0.041), but vGLUT2 levels were similar between medicated schizophrenia subjects and controls. Treatment-resistant subjects had significantly higher TH and GAD67 levels than controls (an increase of 121.0%, P=0.0003 and 58.7%, P=0.004, respectively). These data suggest increases in dopamine and GABA transmission in the SN in schizophrenia, with a potential relation to treatment and response.

  15. Cell-Penetrating Peptide as a Means of Directing the Differentiation of Induced-Pluripotent Stem Cells.

    Science.gov (United States)

    Kaitsuka, Taku; Tomizawa, Kazuhito

    2015-11-06

    Protein transduction using cell-penetrating peptides (CPPs) is useful for the delivery of large protein molecules, including some transcription factors. This method is safer than gene transfection methods with a viral vector because there is no risk of genomic integration of the exogenous DNA. Recently, this method was reported as a means for the induction of induced pluripotent stem (iPS) cells, directing the differentiation into specific cell types and supporting gene editing/correction. Furthermore, we developed a direct differentiation method to obtain a pancreatic lineage from mouse and human pluripotent stem cells via the protein transduction of three transcription factors, Pdx1, NeuroD, and MafA. Here, we discuss the possibility of using CPPs as a means of directing the differentiation of iPS cells and other stem cell technologies.

  16. The Fas pathway is involved in pancreatic beta cell secretory function

    DEFF Research Database (Denmark)

    Schumann, Desiree M; Maedler, Kathrin; Franklin, Isobel

    2007-01-01

    Pancreatic beta cell mass and function increase in conditions of enhanced insulin demand such as obesity. Failure to adapt leads to diabetes. The molecular mechanisms controlling this adaptive process are unclear. Fas is a death receptor involved in beta cell apoptosis or proliferation, depending...... on the activity of the caspase-8 inhibitor FLIP. Here we show that the Fas pathway also regulates beta cell secretory function. We observed impaired glucose tolerance in Fas-deficient mice due to a delayed and decreased insulin secretory pattern. Expression of PDX-1, a beta cell-specific transcription factor...... regulating insulin gene expression and mitochondrial metabolism, was decreased in Fas-deficient beta cells. As a consequence, insulin and ATP production were severely reduced and only partly compensated for by increased beta cell mass. Up-regulation of FLIP enhanced NF-kappaB activity via NF...

  17. Equation of the fixed membrane in the n-dimensional space: some remarks on the maxima of the eigenfunctions subjected to various norms

    Directory of Open Access Journals (Sweden)

    Yves Biollay

    1979-01-01

    Full Text Available We show in this paper that the sequence {max|uk|}, where the uk are the eigenfunctions of the problem Δu+λu=0 in D⊂Rn and u=0 on ∂D, is not bounded generally if one imposes the norm ∫Du2p(xdx=1, p=(1,2,3,…. The same holds with the norm ∫D|gradu|2pdx=1 when n>4p−1. On the other hand, if D⊂R2, resp. R3 the norm ∫D|gradu|2dx=1 implies max|uk|→k→∞0, resp. max|uk|=0(1.

  18. Phosphorylation events implicating p38 and PI3K mediate tungstate-effects in MIN6 beta cells

    International Nuclear Information System (INIS)

    Piquer, Sandra; Barcelo-Batllori, Silvia; Julia, Marta; Marzo, Nuria; Nadal, Belen; Guinovart, Joan J.; Gomis, Ramon

    2007-01-01

    Oral administration of sodium tungstate is an effective treatment for diabetes in animal models. Several lines of evidence indicate the pancreatic beta cell as one of the targets of tungstate action. Here, we examined the molecular mechanism by which this compound exerts its effects on the beta cell line MIN6. Tungstate treatment induced phosphorylation and subsequent activation of p38 and PI3K which in turn are implicated in tungstate PDX-1 nuclear localization and activation. Although no effect was observed in glucose-induced insulin secretion we found that tungstate activates basal insulin release, a process driven, at least in part, by activation of p38. These results show a direct involvement of p38 and PI3K phosphorylation in the mechanism of action of tungstate in the beta cell

  19. YKL-40 is differentially expressed in human embryonic stem cells and in cell progeny of the three germ layers

    DEFF Research Database (Denmark)

    Brøchner, Christian B; Johansen, Julia S; Larsen, Lars A

    2012-01-01

    oxygen tension, in culture medium with or without basic fibroblast growth factor, and on feeder layers comprising mouse embryonic fibroblasts or human foreskin fibroblasts to evaluate whether hESCs and their progeny produced YKL-40 and to characterize YKL-40 expression during differentiation. Secreted......The secreted glycoprotein YKL-40 participates in cell differentiation, inflammation, and cancer progression. High YKL-40 expression is reported during early human development, but its functions are unknown. Six human embryonic stem cell (hESC) lines were cultured in an atmosphere of low or high...... YKL-40 protein and YKL-40 mRNA expression were measured by enzyme-linked immunosorbent assay (ELISA) and quantitative RT-PCR. Serial-sectioned colonies were stained for YKL-40 protein and for pluripotent hESC (OCT4, NANOG) and germ layer (HNF-3ß, PDX1, CD34, p63, nestin, PAX6) markers. Double...

  20. Cell-Penetrating Peptide as a Means of Directing the Differentiation of Induced-Pluripotent Stem Cells

    Directory of Open Access Journals (Sweden)

    Taku Kaitsuka

    2015-11-01

    Full Text Available Protein transduction using cell-penetrating peptides (CPPs is useful for the delivery of large protein molecules, including some transcription factors. This method is safer than gene transfection methods with a viral vector because there is no risk of genomic integration of the exogenous DNA. Recently, this method was reported as a means for the induction of induced pluripotent stem (iPS cells, directing the differentiation into specific cell types and supporting gene editing/correction. Furthermore, we developed a direct differentiation method to obtain a pancreatic lineage from mouse and human pluripotent stem cells via the protein transduction of three transcription factors, Pdx1, NeuroD, and MafA. Here, we discuss the possibility of using CPPs as a means of directing the differentiation of iPS cells and other stem cell technologies.

  1. Diabetic Hyperglycemia: Link to Impaired Glucose Transport in Pancreatic β Cells

    Science.gov (United States)

    Unger, Roger H.

    1991-03-01

    Glucose uptake into pancreatic β cells by means of the glucose transporter GLUT-2, which has a high Michaelis constant, is essential for the normal insulin secretory response to hyperglycemia. In both autoimmune and nonautoimmune diabetes, this glucose transport is reduced as a consequence of down-regulation of the normal β-cell transporter. In autoimmune diabetes, circulating immunoglobulins can further impair this glucose transport by inhibiting functionally intact transporters. Insights into mechanisms of the unresponsiveness of β cells to hyperglycemia may improve the management and prevention of diabetes.

  2. Molecular mechanisms of action of styrene toxicity in blood plasma and liver.

    Science.gov (United States)

    Niaz, Kamal; Mabqool, Faheem; Khan, Fazlullah; Ismail Hassan, Fatima; Baeeri, Maryam; Navaei-Nigjeh, Mona; Hassani, Shokoufeh; Gholami, Mahdi; Abdollahi, Mohammad

    2017-10-01

    Styrene is an aromatic colorless hydrocarbon available in liquid form and highly volatile. In its pure form, it gives a sweet smell. The primary source of exposure in the environment is from plastic materials, rubber industries, packaging materials, insulations, and fiber glass and carpet industry. Natural sources of styrene include: few metabolites in plants which are transferred through food chain. The current study was designed to evaluate styrene toxicity, including: superoxide dismutase (SOD) and protein carbonyl, oxidative stress, glucose-6-phosphatase (G6Pase), glycogen phosphorylase (GP), and phosphoenolpyruvate carboxykinase (PEPCK) activities, adenosine triphosphate (ATP) to adenosine diphosphate (ADP) ratio, and changes in gene expressions such as glutamate dehydrogenase 1 (GLUD1), glucose transporter 2 (GLUT2), and glucokinase (GCK) in the rat liver tissue. For this purpose, styrene was dissolved in corn oil and was administered via gavage, at doses 250, 500, 1000, 1500, 2000, mg/kg/day per mL and control (corn oil) to each rat with one day off in a week, for 42 days. Plasma SOD and protein carbonyl of plasma were significantly up-regulated in 1000, 1500, and 2000 mg/kg/day styrene administrated groups (P < .001). In addition, styrene caused an increase in lipid peroxidation (LPO) and reactive oxygen species (ROS) in the dose-dependent manners in liver tissue (P < .001). Furthermore, the ferrous reducing antioxidant power (FRAP) and total thiol molecules (TTM) in styrene-treated groups were significantly decreased in liver tissue (P < .001) with increasing doses. In treated rats, styrene significantly increased G6Pase activity (P < .001) and down-regulated GP activity (P < .001) as compared to the control group. The PEPCK activity was significantly raised in a dose-dependent manner (P < .001). The ATP/ADP ratio of live cells was significantly raised by increasing the dose (P < .001). There was significantly an up

  3. Glucose-responsive neurons of the paraventricular thalamus control sucrose-seeking behavior.

    Science.gov (United States)

    Labouèbe, Gwenaël; Boutrel, Benjamin; Tarussio, David; Thorens, Bernard

    2016-08-01

    Feeding behavior is governed by homeostatic needs and motivational drive to obtain palatable foods. Here, we identify a population of glutamatergic neurons in the paraventricular thalamus of mice that express the glucose transporter Glut2 (encoded by Slc2a2) and project to the nucleus accumbens. These neurons are activated by hypoglycemia and, in freely moving mice, their activation by optogenetics or Slc2a2 inactivation increases motivated sucrose-seeking but not saccharin-seeking behavior. These neurons may control sugar overconsumption in obesity and diabetes.

  4. Epigenetic mechanisms of peptidergic regulation of gene expression during aging of human cells.

    Science.gov (United States)

    Ashapkin, V V; Linkova, N S; Khavinson, V Kh; Vanyushin, B F

    2015-03-01

    Expression levels of genes encoding specific transcription factors and other functionally important proteins vary upon aging of pancreatic and bronchial epithelium cell cultures. The peptides KEDW and AEDL tissue-specifically affect gene expression in pancreatic and bronchial cell cultures, respectively. It is established in this work that the DNA methylation patterns of the PDX1, PAX6, NGN3, NKX2-1, and SCGB1A1 gene promoter regions change upon aging in pancreatic and bronchial cell cultures in correlation with variations in their expression levels. Thus, stable changes in gene expression upon aging of cell cultures could be caused by changes in their promoter methylation patterns. The methylation patterns of the PAX4 gene in pancreatic cells as well as those of the FOXA1, SCGB3A2, and SFTPA1 genes in bronchial cells do not change upon aging and are unaffected by peptides, whereas their expression levels change in both cases. The promoter region of the FOXA2 gene in pancreatic cells contains a small number of methylated CpG sites, their methylation levels being affected by cell culture aging and KEDW, though without any correlation with gene expression levels. The promoter region of the FOXA2 gene is completely unmethylated in bronchial cells irrespective of cell culture age and AEDL action. Changes in promoter methylation might be the cause of age- and peptide-induced variations in expression levels of the PDX1, PAX6, and NGN3 genes in pancreatic cells and NKX2-1 and SCGB1A1 genes in bronchial cells. Expression levels of the PAX4 and FOXA2 genes in pancreatic cells and FOXA1, FOXA2, SCGB3A2, and SFTPA1 genes in bronchial cells seem to be controlled by some other mechanisms.

  5. cGMP may have trophic effects on beta cell function comparable to those of cAMP, implying a role for high-dose biotin in prevention/treatment of diabetes.

    Science.gov (United States)

    McCarty, Mark F

    2006-01-01

    Incretin hormones have trophic effects on beta cell function that can aid prevention and treatment of diabetes. cAMP is the primary mediator of these effects, and has been shown to potentiate glucose-stimulated insulin secretion, promote proper beta cells differentiation by increasing expression of the crucial transcription factor PDX-1, and prevent beta cell apoptosis. cGMP's role in beta cell function has received far less scrutiny, but there is emerging evidence that it may have a trophic impact on beta cell function analogous to that of cAMP. An increase in plasma glucose boosts beta cell production of cGMP, which acts as a feed-forward mediator to enhance glucose-stimulated insulin secretion. cGMP also has an anti-apoptotic effect in beta cells, and there is now indirect evidence that it promotes expression of PDX-1. Supraphysiological concentrations of biotin can directly activate guanylate cyclase, and there is limited evidence that high intakes of this vitamin can be therapeutically beneficial in diabetics and in rodent models of diabetes. Beneficial effects of cGMP on muscle insulin sensitivity and on control of hepatic glucose output may contribute to biotin's utility in diabetes. The fact that nitric oxide/cGMP exert a range of favorable effects on vascular health should further encourage exploration of biotin's preventive and therapeutic potential. If an appropriate high-dose biotin regimen could achieve a modest systemic increase in guanylate cyclase activity, without entailing unacceptable side effects or risks, such a regimen might have considerable potential for promoting vascular health and preventing or managing diabetes.

  6. Persistence of Coxsackievirus B4 in pancreatic ductal-like cells results in cellular and viral changes.

    Science.gov (United States)

    Alidjinou, E K; Engelmann, I; Bossu, J; Villenet, C; Figeac, M; Romond, M-B; Sané, F; Hober, D

    2017-10-03

    Although known as cytolytic viruses, group B coxackieviruses (CVB) are able to establish a persistent infection in vitro and in vivo. Viral persistence has been reported as a key mechanism in the pathogenesis of CVB-associated chronic diseases such as type 1 diabetes (T1D). The impact of CVB4 persistence on human pancreas ductal-like cells was investigated. A persistent CVB4 infection was established in ductal-like cells. PDX-1 expression, resistance to CVB4-induced lysis and CAR expression were evaluated. The profile of cellular microRNAs (miRNAs) was investigated through miRNA-sequencing. Viral phenotypic changes were examined, and genomic modifications were assessed by sequencing of the viral genome. The CVB4 persistence in ductal-like cells was productive, with continuous release of infectious particles. Persistently infected cells displayed a resistance to CVB4-induced lysis upon superinfection and expression of PDX-1 and CAR was decreased. These changes were maintained even after virus clearance. The patterns of cellular miRNA expression in mock-infected and in CVB4-persistently infected ductal-like cells were clearly different. The persistent infection-derived virus (PIDV) was still able to induce cytopathic effect but its plaques were smaller than the parental virus. Several mutations appeared in various PIDV genome regions, but amino acid substitutions did not affect the predicted site of interaction with CAR. Cellular and viral changes occur during persistent infection of human pancreas ductal-like cells with CVB4. The persistence of cellular changes even after virus clearance supports the hypothesis of a long-lasting impact of persistent CVB infection on the cells.

  7. Laminin-10 and Its Receptors in Breast Carcinoma: Cooperation of Alpha6Beta4 and Alpha3Beta1 Integrin Laminin Receptors in Breast Carcinoma

    National Research Council Canada - National Science Library

    Awwad, Rana

    2003-01-01

    .... In fact, IRS-1 function might reduce the efficacy of IRS-2 in these processes. Altogether, the findings suggest that IRS-1 is involved in the early stages of breast cancer establishment and that IRS-2 is required for its maintenance and progression to malignancy. (6 figures, 20 refs.)

  8. Insulin receptor substrate 1 expression enhances the sensitivity of 32D cells to chemotherapy-induced cell death

    Science.gov (United States)

    Porter, Holly A.; Carey, Gregory B.; Keegan, Achsah D.

    2012-01-01

    The adaptors IRS1 and IRS2 link growth factor receptors to downstream signaling pathways that regulate proliferation and survival. Both suppress factor-withdrawal-induced apoptosis and have been implicated in cancer progression. However, recent studies suggest IRS1 and IRS2 mediate differential functions in cancer pathogenesis. IRS1 promoted breast cancer proliferation, while IRS2 promoted metastasis. The role of IRS1 and IRS2 in controlling cell responses to chemotherapy is unknown. To determine the role of IRS1 and IRS2 in the sensitivity of cells to chemotherapy, we treated 32D cells lacking or expressing IRS proteins with various concentrations of chemotherapeutic agents. We found that expression of IRS1, in contrast to IRS2, enhanced the sensitivity of 32D cells to chemotherapy-induced apoptosis. When IRS2 was expressed with IRS1, the cells no longer showed enhanced sensitivity. Expression of IRS1 did not alter the expression of pro- and anti-apoptotic proteins; however, 32D-IRS1 cells expressed higher levels of Annexin A2. In 32D-IRS1 cells, IRS1 and Annexin A2 were both located in cytoplasmic and membrane fractions. We also found that IRS1 coprecipitated with Annexin A2, while IRS2 did not. Decreasing Annexin A2 levels reduced 32D-IRS1 cell sensitivity to chemotherapy. These results suggest IRS1 enhances sensitivity to chemotherapy in part through Annexin A2. PMID:22652453

  9. Functional defect of truncated hepatocyte nuclear factor-1{alpha} (G554fsX556) associated with maturity-onset diabetes of the young

    Energy Technology Data Exchange (ETDEWEB)

    Kooptiwut, Suwattanee, E-mail: S_kooptiwut@hotmail.com [Department of Physiology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700 (Thailand); Sujjitjoon, Jatuporn [Department of Immunology and Immunology Graduate Program, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700 (Thailand); Plengvidhya, Nattachet [Department of Immunology and Immunology Graduate Program, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700 (Thailand); Division of Endocrinology and Metabolism, Department of Medicine, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700 (Thailand); Boonyasrisawat, Watip; Chongjaroen, Nalinee; Jungtrakoon, Prapapron [Department of Immunology and Immunology Graduate Program, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700 (Thailand); Semprasert, Namoiy [Department of Physiology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700 (Thailand); Furuta, Hiroto; Nanjo, Kishio [The First Department, Wakayama Medical University (Japan); Banchuin, Napatawn [Department of Immunology and Immunology Graduate Program, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700 (Thailand); Yenchitsomanus, Pa-thai [Division of Medical Molecular Biology, Medicine Department of Research and Development, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700 (Thailand); Medical Biotechnology Unit, National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency (NSTDA), Bangkok (Thailand)

    2009-05-22

    A novel frameshift mutation attributable to 14-nucleotide insertion in hepatocyte nuclear factor-1{alpha} (HNF-1{alpha}) encoding a truncated HNF-1{alpha} (G554fsX556) with 76-amino acid deletion at its carboxyl terminus was identified in a Thai family with maturity-onset diabetes of the young (MODY). The wild-type and mutant HNF-1{alpha} proteins were expressed by in vitro transcription and translation (TNT) assay and by transfection in HeLa cells. The wild-type and mutant HNF-1{alpha} could similarly bind to human glucose-transporter 2 (GLUT2) promoter examined by electrophoretic mobility shift assay (EMSA). However, the transactivation activities of mutant HNF-1{alpha} on human GLUT2 and rat L-type pyruvate kinase (L-PK) promoters in HeLa cells determined by luciferase reporter assay were reduced to approximately 55-60% of the wild-type protein. These results suggested that the functional defect of novel truncated HNF-1{alpha} (G554fsX556) on the transactivation of its target-gene promoters would account for the {beta}-cell dysfunction associated with the pathogenesis of MODY.

  10. Functional defect of truncated hepatocyte nuclear factor-1α (G554fsX556) associated with maturity-onset diabetes of the young

    International Nuclear Information System (INIS)

    Kooptiwut, Suwattanee; Sujjitjoon, Jatuporn; Plengvidhya, Nattachet; Boonyasrisawat, Watip; Chongjaroen, Nalinee; Jungtrakoon, Prapapron; Semprasert, Namoiy; Furuta, Hiroto; Nanjo, Kishio; Banchuin, Napatawn; Yenchitsomanus, Pa-thai

    2009-01-01

    A novel frameshift mutation attributable to 14-nucleotide insertion in hepatocyte nuclear factor-1α (HNF-1α) encoding a truncated HNF-1α (G554fsX556) with 76-amino acid deletion at its carboxyl terminus was identified in a Thai family with maturity-onset diabetes of the young (MODY). The wild-type and mutant HNF-1α proteins were expressed by in vitro transcription and translation (TNT) assay and by transfection in HeLa cells. The wild-type and mutant HNF-1α could similarly bind to human glucose-transporter 2 (GLUT2) promoter examined by electrophoretic mobility shift assay (EMSA). However, the transactivation activities of mutant HNF-1α on human GLUT2 and rat L-type pyruvate kinase (L-PK) promoters in HeLa cells determined by luciferase reporter assay were reduced to approximately 55-60% of the wild-type protein. These results suggested that the functional defect of novel truncated HNF-1α (G554fsX556) on the transactivation of its target-gene promoters would account for the β-cell dysfunction associated with the pathogenesis of MODY.

  11. EGCG evokes Nrf2 nuclear translocation and dampens PTP1B expression to ameliorate metabolic misalignment under insulin resistance condition.

    Science.gov (United States)

    Mi, Yashi; Zhang, Wentong; Tian, Haoyu; Li, Runnan; Huang, Shuxian; Li, Xingyu; Qi, Guoyuan; Liu, Xuebo

    2018-03-01

    As a major nutraceutical component of green tea (-)-epigallocatechin-3-gallate (EGCG) has attracted interest from scientists due to its well-documented antioxidant and antiobesity bioactivities. In the current study, we aimed to investigate the protective effect of EGCG on metabolic misalignment and in balancing the redox status in mice liver and HepG2 cells under insulin resistance condition. Our results indicated that EGCG accelerates the glucose uptake and evokes IRS-1/Akt/GLUT2 signaling pathway via dampening the expression of protein tyrosine phosphatase 1B (PTP1B). Consistently, ectopic expression of PTP1B by Ad-PTP1B substantially impaired EGCG-elicited IRS-1/Akt/GLUT2 signaling pathway. Moreover, EGCG co-treatment stimulated nuclear translocation of Nrf2 by provoking P13K/AKT signaling pathway and thus modulated the downstream expressions of antioxidant enzymes such as HO-1 and NQO-1 in HepG2 cells. Furthermore, knockdown Nrf2 by small interfering RNA (siRNA) notably enhanced the expression of PTP1B and blunt EGCG-stimulated glucose uptake. Consistent with these results, in vivo study revealed that EGCG supplement significantly ameliorated high-fat and high-fructose diet (HFFD)-triggered insulin resistance and oxidative stress by up-regulating the IRS-1/AKT and Keap1/Nrf2 transcriptional pathways. Administration of an appropriate chemopreventive agent, such as EGCG, could potentially serve as an additional therapeutic intervention in the arsenal against obesity.

  12. The ontogeny of nutrient transporter and digestive enzyme gene expression in domestic pigeon (Columba livia) intestine and yolk sac membrane during pre- and posthatch development.

    Science.gov (United States)

    Dong, X Y; Wang, Y M; Yuan, C; Zou, X T

    2012-08-01

    To better understand the digestive capacity in domestic pigeons (Columba livia), this study was conducted to evaluate nutrient transporters and digestive enzymes gene expression in small intestine and yolk sac membrane (YSM) during pre- and posthatch development. We investigated the oligopeptide transporter Pept1, sodium glucose transporter SGLT1, glucose transporter GLUT2, aminopeptidase-N (APN), and sucrase-isomaltase (SI). Intestine was collected at embryo d 12, 14, and 16, day of hatch, and d 1, 3, 5, 8, and 14 posthatch. The YSM was collected at embryo d 12, 14, 16, and day of hatch. The cDNA fragments for Pept1, SGLT1, GLUT2, APN, and SI were isolated and cloned using reverse-transcription PCR. The sequences data showed that these genes were highly identical to the gene of chicken. The mRNA expression of each gene was assayed using real-time PCR. Expression of intestinal nutrient transporters increased linearly (Ppigeons and establish a foundation for future research on the nutrients requirements for young pigeons.

  13. Nicotinamide induces differentiation of embryonic stem cells into insulin-secreting cells

    International Nuclear Information System (INIS)

    Vaca, Pilar; Berna, Genoveva; Araujo, Raquel; Carneiro, Everardo M.; Bedoya, Francisco J.; Soria, Bernat; Martin, Franz

    2008-01-01

    The poly(ADP-ribose) polymerase (PARP) inhibitor, nicotinamide, induces differentiation and maturation of fetal pancreatic cells. In addition, we have previously reported evidence that nicotinamide increases the insulin content of cells differentiated from embryonic stem (ES) cells, but the possibility of nicotinamide acting as a differentiating agent on its own has never been completely explored. Islet cell differentiation was studied by: (i) X-gal staining after neomycin selection; (ii) BrdU studies; (iii) single and double immunohistochemistry for insulin, C-peptide and Glut-2; (iv) insulin and C-peptide content and secretion assays; and (v) transplantation of differentiated cells, under the kidney capsule, into streptozotocin (STZ)-diabetic mice. Here we show that undifferentiated mouse ES cells treated with nicotinamide: (i) showed an 80% decrease in cell proliferation; (ii) co-expressed insulin, C-peptide and Glut-2; (iii) had values of insulin and C-peptide corresponding to 10% of normal mouse islets; (iv) released insulin and C-peptide in response to stimulatory glucose concentrations; and (v) after transplantation into diabetic mice, normalized blood glucose levels over 7 weeks. Our data indicate that nicotinamide decreases ES cell proliferation and induces differentiation into insulin-secreting cells. Both aspects are very important when thinking about cell therapy for the treatment of diabetes based on ES cells

  14. Prion protein modulates glucose homeostasis by altering intracellular iron.

    Science.gov (United States)

    Ashok, Ajay; Singh, Neena

    2018-04-26

    The prion protein (PrP C ), a mainly neuronal protein, is known to modulate glucose homeostasis in mouse models. We explored the underlying mechanism in mouse models and the human pancreatic β-cell line 1.1B4. We report expression of PrP C on mouse pancreatic β-cells, where it promoted uptake of iron through divalent-metal-transporters. Accordingly, pancreatic iron stores in PrP knockout mice (PrP -/- ) were significantly lower than wild type (PrP +/+ ) controls. Silencing of PrP C in 1.1B4 cells resulted in significant depletion of intracellular (IC) iron, and remarkably, upregulation of glucose transporter GLUT2 and insulin. Iron overloading, on the other hand, resulted in downregulation of GLUT2 and insulin in a PrP C -dependent manner. Similar observations were noted in the brain, liver, and neuroretina of iron overloaded PrP +/+ but not PrP -/- mice, indicating PrP C -mediated modulation of insulin and glucose homeostasis through iron. Peripheral challenge with glucose and insulin revealed blunting of the response in iron-overloaded PrP +/+ relative to PrP -/- mice, suggesting that PrP C -mediated modulation of IC iron influences both secretion and sensitivity of peripheral organs to insulin. These observations have implications for Alzheimer's disease and diabetic retinopathy, known complications of type-2-diabetes associated with brain and ocular iron-dyshomeostasis.

  15. Highly Efficient Red and White Organic Light-Emitting Diodes with External Quantum Efficiency beyond 20% by Employing Pyridylimidazole-Based Metallophosphors.

    Science.gov (United States)

    Miao, Yanqin; Tao, Peng; Wang, Kexiang; Li, Hongxin; Zhao, Bo; Gao, Long; Wang, Hua; Xu, Bingshe; Zhao, Qiang

    2017-11-01

    Two highly efficient red neutral iridium(III) complexes, Ir1 and Ir2, were rationally designed and synthesized by selecting two pyridylimidazole derivatives as the ancillary ligands. Both Ir1 and Ir2 show nearly the same photoluminescence emission with the maximum peak at 595 nm (shoulder band at about 638 nm) and achieve high solution quantum yields of up to 0.47 for Ir1 and 0.57 for Ir2. Employing Ir1 and Ir2 as emitters, the fabricated red organic light-emitting diodes (OLEDs) show outstanding performance with the maximum external quantum efficiency (EQE), current efficiency (CE), and power efficiency (PE) of 20.98%, 33.04 cd/A, and 33.08 lm/W for the Ir1-based device and 22.15%, 36.89 cd/A, and 35.85 lm/W for the Ir2-based device, respectively. Furthermore, using Ir2 as red emitter, a trichromatic hybrid white OLED, showing good warm white emission with low correlated color temperature of white device also realizes excellent device efficiencies with the maximum EQE, CE, and PE reaching 22.74%, 44.77 cd/A, and 46.89 lm/W, respectively. Such high electroluminescence performance for red and white OLEDs indicates that Ir1 and Ir2 as efficient red phosphors have great potential for future OLED displays and lightings applications.

  16. Insulin receptor substrate 1 expression enhances the sensitivity of 32D cells to chemotherapy-induced cell death

    International Nuclear Information System (INIS)

    Porter, Holly A.; Carey, Gregory B.; Keegan, Achsah D.

    2012-01-01

    The adapters IRS1 and IRS2 link growth factor receptors to downstream signaling pathways that regulate proliferation and survival. Both suppress factor-withdrawal-induced apoptosis and have been implicated in cancer progression. However, recent studies suggest IRS1 and IRS2 mediate differential functions in cancer pathogenesis. IRS1 promoted breast cancer proliferation, while IRS2 promoted metastasis. The role of IRS1 and IRS2 in controlling cell responses to chemotherapy is unknown. To determine the role of IRS1 and IRS2 in the sensitivity of cells to chemotherapy, we treated 32D cells lacking or expressing IRS proteins with various concentrations of chemotherapeutic agents. We found that expression of IRS1, in contrast to IRS2, enhanced the sensitivity of 32D cells to chemotherapy-induced apoptosis. When IRS2 was expressed with IRS1, the cells no longer showed enhanced sensitivity. Expression of IRS1 did not alter the expression of pro- and anti-apoptotic proteins; however, 32D-IRS1 cells expressed higher levels of Annexin A2. In 32D-IRS1 cells, IRS1 and Annexin A2 were both located in cytoplasmic and membrane fractions. We also found that IRS1 coprecipitated with Annexin A2, while IRS2 did not. Decreasing Annexin A2 levels reduced 32D-IRS1 cell sensitivity to chemotherapy. These results suggest IRS1 enhances sensitivity to chemotherapy in part through Annexin A2. -- Highlights: ► IRS1 enhanced the sensitivity of 32D cells to chemotherapy-induced apoptosis. ► This sensitivity is abrogated by the expression of IRS2. ► Expressing IRS1 in 32D cells increased levels of Annexin A2. ► Both IRS1 and Annexin A2 were located in cytoplasmic and membrane fractions. ► Decreasing Annexin A2 in 32D-IRS1 cells abated their sensitivity to chemotherapy.

  17. RESEARCH ARTICLE

    Indian Academy of Sciences (India)

    women with PCOS are at a higher risk for gestational diabetes, miscarriages, ..... meta- analysis on PCOS women reported that Gly/Arg and Gly/Gly genotype is ... IRS1 and IRS2 polymorphisms influence glucose homeostasis and could.

  18. IceBridge HiCARS 2 L0 Raw Return Energy Amplitudes

    Data.gov (United States)

    National Aeronautics and Space Administration — The NASA IceBridge HiCARS 2 Level-0 Raw Return Energy Amplitudes (IR2HI0) data set contains radar sounder measurements taken over Antarctica using the Hi-Capability...

  19. Regulation of Blood Pressure, Appetite, and Glucose by Leptin After Inactivation of Insulin Receptor Substrate 2 Signaling in the Entire Brain or in Proopiomelanocortin Neurons.

    Science.gov (United States)

    do Carmo, Jussara M; da Silva, Alexandre A; Wang, Zhen; Freeman, Nathan J; Alsheik, Ammar J; Adi, Ahmad; Hall, John E

    2016-02-01

    Insulin receptor substrate 2 (IRS2) is one of the 3 major leptin receptor signaling pathways, but its role in mediating the chronic effects of leptin on blood pressure, food intake, and glucose regulation is unclear. We tested whether genetic inactivation of IRS2 in the entire brain (IRS2/Nestin-cre mice) or specifically in proopiomelanocortin (POMC) neurons (IRS2/POMC-cre mice) attenuates the chronic cardiovascular, metabolic, and antidiabetic effects of leptin. Mice were instrumented with telemetry probes for measurement of blood pressure and heart rate and with venous catheters for intravenous infusions. After a 5-day control period, mice received leptin infusion (2 μg/kg per minute) for 7 days. Compared with control IRS2(flox/flox) mice, IRS2/POMC-cre mice had similar body weight and food intake (33±1 versus 35±1 g and 3.6±0.5 versus 3.8±0.2 g per day) but higher mean arterial pressure (MAP) and heart rate (110±2 versus 102±2 mm Hg and 641±9 versus 616±5 bpm). IRS2/Nestin-cre mice were heavier (38±2 g), slightly hyperphagic (4.5±1.0 g per day), and had higher MAP and heart rate (108±2 mm Hg and 659±9 bpm) compared with control mice. Leptin infusion gradually increased MAP despite decreasing food intake by 31% in IRS2(flox/flox) and in Nestin-cre control mice. In contrast, leptin infusion did not change MAP in IRS2/Nestin-cre or IRS2/POMC-cre mice. The anorexic and antidiabetic effects of leptin, however, were similar in all 3 groups. These results indicate that IRS2 signaling in the central nervous system, and particularly in POMC neurons, is essential for the chronic actions of leptin to raise MAP but not for its anorexic or antidiabetic effects. © 2015 American Heart Association, Inc.

  20. Phosphatidylcholine Transfer Protein Interacts with Thioesterase Superfamily Member 2 to Attenuate Insulin Signaling

    OpenAIRE

    Ersoy, Baran A.; Tarun, Akansha; D’Aquino, Katharine; Hancer, Nancy J.; Ukomadu, Chinweike; White, Morris F.; Michel, Thomas; Manning, Brendan D.; Cohen, David E.

    2013-01-01

    Phosphatidylcholine transfer protein (PC-TP) is a phospholipid-binding protein that is enriched in liver and that interacts with thioesterase superfamily member 2 (THEM2). Mice lacking either protein exhibit improved hepatic glucose homeostasis and are resistant to diet-induced diabetes. Insulin receptor substrate 2 (IRS2) and mammalian target of rapamycin complex 1 (mTORC1) are key effectors of insulin signaling, which is attenuated in diabetes. We found that PC-TP inhibited IRS2, as evidenc...

  1. Niche-dependent development of functional neuronal networks from embryonic stem cell-derived neural populations

    Directory of Open Access Journals (Sweden)

    Siebler Mario

    2009-08-01

    Full Text Available Abstract Background The present work was performed to investigate the ability of two different embryonic stem (ES cell-derived neural precursor populations to generate functional neuronal networks in vitro. The first ES cell-derived neural precursor population was cultivated as free-floating neural aggregates which are known to form a developmental niche comprising different types of neural cells, including neural precursor cells (NPCs, progenitor cells and even further matured cells. This niche provides by itself a variety of different growth factors and extracellular matrix proteins that influence the proliferation and differentiation of neural precursor and progenitor cells. The second population was cultivated adherently in monolayer cultures to control most stringently the extracellular environment. This population comprises highly homogeneous NPCs which are supposed to represent an attractive way to provide well-defined neuronal progeny. However, the ability of these different ES cell-derived immature neural cell populations to generate functional neuronal networks has not been assessed so far. Results While both precursor populations were shown to differentiate into sufficient quantities of mature NeuN+ neurons that also express GABA or vesicular-glutamate-transporter-2 (vGlut2, only aggregate-derived neuronal populations exhibited a synchronously oscillating network activity 2–4 weeks after initiating the differentiation as detected by the microelectrode array technology. Neurons derived from homogeneous NPCs within monolayer cultures did merely show uncorrelated spiking activity even when differentiated for up to 12 weeks. We demonstrated that these neurons exhibited sparsely ramified neurites and an embryonic vGlut2 distribution suggesting an inhibited terminal neuronal maturation. In comparison, neurons derived from heterogeneous populations within neural aggregates appeared as fully mature with a dense neurite network and punctuated

  2. PGBR extract ameliorates TNF-α induced insulin resistance in hepatocytes

    Directory of Open Access Journals (Sweden)

    Fu-Chih Chen

    2018-01-01

    Full Text Available Pre-germinated brown rice (PGBR could ameliorate metabolic syndrome, however, not much research estimates the effect of PGBR extract on insulin resistance. The aim of this study is to examine the effects of PGBR extract in TNF-α induced insulin resistance. HepG2 cells, hepatocytes, were cultured in DMEM medium and added with 5 μM insulin or with insulin and 30 ng/ml TNF-α or with insulin, TNF-α and PGBR extract (50, 100, 300 μg/ml. The glucose levels of the medium were decreased by insulin, demonstrating insulin promoted glucose uptake into cell. However, TNF-α inhibited glucose uptake into cells treated with insulin. Moreover, insulin increased the protein expressions of AMP-activated protein kinase (AMPK, insulin receptor substrate-1 (IRS-1, phosphatidylinositol-3-kinase-α (PI3K-α, serine/threonine kinase PI3K-linked protein kinase B (Akt/PKB, glucose transporter-2 (GLUT-2, glucokinase (GCK, peroxisome proliferator activated receptor-α (PPAR-α and PPAR-γ. TNF-α activated p65 and MAPKs (JNK1/2 and ERK1/2 which worsened the expressions of AMPK, IRS-1, PI3K-α, Akt/PKB, GLUT-2, GCK, glycogen synthase kinase-3 (GSK-3, PPAR-α and PPAR-γ. Once this relationship was established, we added PGBR extract to cell with insulin and TNF-α. We found glucose levels of medium were lowered and that the protein expressions of AMPK, IRS-1, PI3K-α, Akt/PKB, GLUT-2, GCK, GSK-3, PPAR-α, PPAR-γ and p65, JNK1/2 were also recovered. In conclusion, this study found that TNF-α inhibited insulin stimulated glucose uptake and aggravated related proteins expressions, suggesting that it might cause insulin resistance. PGBR extract was found to ameliorate this TNF-α induced insulin resistance, suggesting that it might be used in the future to help control insulin resistance.

  3. Interleukins 2, 4, 7, and 15 stimulate tyrosine phosphorylation of insulin receptor substrates 1 and 2 in T cells. Potential role of JAK kinases.

    Science.gov (United States)

    Johnston, J A; Wang, L M; Hanson, E P; Sun, X J; White, M F; Oakes, S A; Pierce, J H; O'Shea, J J

    1995-12-01

    The signaling molecules insulin receptor substrate (IRS)-1 and the newly described IRS-2 (4PS) molecule are major insulin and interleukin 4 (IL-4)-dependent phosphoproteins. We report here that IL-2, IL-7, and IL-15, as well as IL-4, rapidly stimulate the tyrosine phosphorylation of IRS-1 and IRS-2 in human peripheral blood T cells, NK cells, and in lymphoid cell lines. In addition, we show that the Janus kinases, JAK1 and JAK3, associate with IRS-1 and IRS-2 in T cells. Coexpression studies demonstrate that these kinases can tyrosine-phosphorylate IRS-2, suggesting a possible mechanism by which cytokine receptors may induce the tyrosine phosphorylation of IRS-1 and IRS-2. We further demonstrate that the p85 subunit of phosphoinositol 3-kinase associates with IRS-1 in response to IL-2 and IL-4 in T cells. Therefore, these data indicate that IRS-1 and IRS-2 may have important roles in T lymphocyte activation not only in response to IL-4, but also in response to IL-2, IL-7, and IL-15.

  4. Cellular homeoproteins, SATB1 and CDP, bind to the unique region between the human cytomegalovirus UL127 and major immediate-early genes

    International Nuclear Information System (INIS)

    Lee Jialing; Klase, Zachary; Gao Xiaoqi; Caldwell, Jeremy S.; Stinski, Mark F.; Kashanchi, Fatah; Chao, S.-H.

    2007-01-01

    An AT-rich region of the human cytomegalovirus (CMV) genome between the UL127 open reading frame and the major immediate-early (MIE) enhancer is referred to as the unique region (UR). It has been shown that the UR represses activation of transcription from the UL127 promoter and functions as a boundary between the divergent UL127 and MIE genes during human CMV infection [Angulo, A., Kerry, D., Huang, H., Borst, E.M., Razinsky, A., Wu, J., Hobom, U., Messerle, M., Ghazal, P., 2000. Identification of a boundary domain adjacent to the potent human cytomegalovirus enhancer that represses transcription of the divergent UL127 promoter. J. Virol. 74 (6), 2826-2839; Lundquist, C.A., Meier, J.L., Stinski, M.F., 1999. A strong negative transcriptional regulatory region between the human cytomegalovirus UL127 gene and the major immediate-early enhancer. J. Virol. 73 (11), 9039-9052]. A putative forkhead box-like (FOX-like) site, AAATCAATATT, was identified in the UR and found to play a key role in repression of the UL127 promoter in recombinant virus-infected cells [Lashmit, P.E., Lundquist, C.A., Meier, J.L., Stinski, M.F., 2004. Cellular repressor inhibits human cytomegalovirus transcription from the UL127 promoter. J. Virol. 78 (10), 5113-5123]. However, the cellular factors which associate with the UR and FOX-like region remain to be determined. We reported previously that pancreatic-duodenal homeobox factor-1 (PDX1) bound to a 45-bp element located within the UR [Chao, S.H., Harada, J.N., Hyndman, F., Gao, X., Nelson, C.G., Chanda, S.K., Caldwell, J.S., 2004. PDX1, a Cellular Homeoprotein, Binds to and Regulates the Activity of Human Cytomegalovirus Immediate Early Promoter. J. Biol. Chem. 279 (16), 16111-16120]. Here we demonstrate that two additional cellular homeoproteins, special AT-rich sequence binding protein 1 (SATB1) and CCAAT displacement protein (CDP), bind to the human CMV UR in vitro and in vivo. Furthermore, CDP is identified as a FOX-like binding protein

  5. Nicotine promotes initiation and progression of KRAS-induced pancreatic cancer via Gata6-dependent dedifferentiation of acinar cells in mice.

    Science.gov (United States)

    Hermann, Patrick C; Sancho, Patricia; Cañamero, Marta; Martinelli, Paola; Madriles, Francesc; Michl, Patrick; Gress, Thomas; de Pascual, Ricardo; Gandia, Luis; Guerra, Carmen; Barbacid, Mariano; Wagner, Martin; Vieira, Catarina R; Aicher, Alexandra; Real, Francisco X; Sainz, Bruno; Heeschen, Christopher

    2014-11-01

    Although smoking is a leading risk factor for pancreatic ductal adenocarcinoma (PDAC), little is known about the mechanisms by which smoking promotes initiation or progression of PDAC. We studied the effects of nicotine administration on pancreatic cancer development in Kras(+/LSLG12Vgeo);Elas-tTA/tetO-Cre (Ela-KRAS) mice, Kras(+/LSLG12D);Trp53+/LSLR172H;Pdx-1-Cre (KPC) mice (which express constitutively active forms of KRAS), and C57/B6 mice. Mice were given nicotine for up to 86 weeks to produce blood levels comparable with those of intermediate smokers. Pancreatic tissues were collected and analyzed by immunohistochemistry and reverse transcriptase polymerase chain reaction; cells were isolated and assayed for colony and sphere formation and gene expression. The effects of nicotine were also evaluated in primary pancreatic acinar cells isolated from wild-type, nAChR7a(-/-), Trp53(-/-), and Gata6(-/-);Trp53(-/-) mice. We also analyzed primary PDAC cells that overexpressed GATA6 from lentiviral expression vectors. Administration of nicotine accelerated transformation of pancreatic cells and tumor formation in Ela-KRAS and KPC mice. Nicotine induced dedifferentiation of acinar cells by activating AKT-ERK-MYC signaling; this led to inhibition of Gata6 promoter activity, loss of GATA6 protein, and subsequent loss of acinar differentiation and hyperactivation of oncogenic KRAS. Nicotine also promoted aggressiveness of established tumors as well as the epithelial-mesenchymal transition, increasing numbers of circulating cancer cells and their dissemination to the liver, compared with mice not exposed to nicotine. Nicotine induced pancreatic cells to acquire gene expression patterns and functional characteristics of cancer stem cells. These effects were markedly attenuated in K-Ras(+/LSL-G12D);Trp53(+/LSLR172H);Pdx-1-Cre mice given metformin. Metformin prevented nicotine-induced pancreatic carcinogenesis and tumor growth by up-regulating GATA6 and promoting

  6. COUP-TFII controls mouse pancreatic β-cell mass through GLP-1-β-catenin signaling pathways.

    Directory of Open Access Journals (Sweden)

    Marie Boutant

    Full Text Available The control of the functional pancreatic β-cell mass serves the key homeostatic function of releasing the right amount of insulin to keep blood sugar in the normal range. It is not fully understood though how β-cell mass is determined.Conditional chicken ovalbumin upstream promoter transcription factor II (COUP-TFII-deficient mice were generated and crossed with mice expressing Cre under the control of pancreatic duodenal homeobox 1 (pdx1 gene promoter. Ablation of COUP-TFII in pancreas resulted in glucose intolerance. Beta-cell number was reduced at 1 day and 3 weeks postnatal. Together with a reduced number of insulin-containing cells in the ductal epithelium and normal β-cell proliferation and apoptosis, this suggests decreased β-cell differentiation in the neonatal period. By testing islets isolated from these mice and cultured β-cells with loss and gain of COUP-TFII function, we found that COUP-TFII induces the expression of the β-catenin gene and its target genes such as cyclin D1 and axin 2. Moreover, induction of these genes by glucagon-like peptide 1 (GLP-1 via β-catenin was impaired in absence of COUP-TFII. The expression of two other target genes of GLP-1 signaling, GLP-1R and PDX-1 was significantly lower in mutant islets compared to control islets, possibly contributing to reduced β-cell mass. Finally, we demonstrated that COUP-TFII expression was activated by the Wnt signaling-associated transcription factor TCF7L2 (T-cell factor 7-like 2 in human islets and rat β-cells providing a feedback loop.Our findings show that COUP-TFII is a novel component of the GLP-1 signaling cascade that increases β-cell number during the neonatal period. COUP-TFII is required for GLP-1 activation of the β-catenin-dependent pathway and its expression is under the control of TCF7L2.

  7. Enrichment of human embryonic stem cell-derived NKX6.1-expressing pancreatic progenitor cells accelerates the maturation of insulin-secreting cells in vivo.

    Science.gov (United States)

    Rezania, Alireza; Bruin, Jennifer E; Xu, Jean; Narayan, Kavitha; Fox, Jessica K; O'Neil, John J; Kieffer, Timothy J

    2013-11-01

    Human embryonic stem cells (hESCs) are considered a potential alternative to cadaveric islets as a source of transplantable cells for treating patients with diabetes. We previously described a differentiation protocol to generate pancreatic progenitor cells from hESCs, composed of mainly pancreatic endoderm (PDX1/NKX6.1-positive), endocrine precursors (NKX2.2/synaptophysin-positive, hormone/NKX6.1-negative), and polyhormonal cells (insulin/glucagon-positive, NKX6.1-negative). However, the relative contributions of NKX6.1-negative versus NKX6.1-positive cell fractions to the maturation of functional β-cells remained unclear. To address this question, we generated two distinct pancreatic progenitor cell populations using modified differentiation protocols. Prior to transplant, both populations contained a high proportion of PDX1-expressing cells (~85%-90%) but were distinguished by their relatively high (~80%) or low (~25%) expression of NKX6.1. NKX6.1-high and NKX6.1-low progenitor populations were transplanted subcutaneously within macroencapsulation devices into diabetic mice. Mice transplanted with NKX6.1-low cells remained hyperglycemic throughout the 5-month post-transplant period whereas diabetes was reversed in NKX6.1-high recipients within 3 months. Fasting human C-peptide levels were similar between groups throughout the study, but only NKX6.1-high grafts displayed robust meal-, glucose- and arginine-responsive insulin secretion as early as 3 months post-transplant. NKX6.1-low recipients displayed elevated fasting glucagon levels. Theracyte devices from both groups contained almost exclusively pancreatic endocrine tissue, but NKX6.1-high grafts contained a greater proportion of insulin-positive and somatostatin-positive cells, whereas NKX6.1-low grafts contained mainly glucagon-expressing cells. Insulin-positive cells in NKX6.1-high, but not NKX6.1-low grafts expressed nuclear MAFA. Collectively, this study demonstrates that a pancreatic endoderm

  8. Mechanism of the Suzuki–Miyaura Cross-Coupling Reaction Mediated by [Pd(NHC)(allyl)Cl] Precatalysts

    KAUST Repository

    Meconi, Giulia Magi

    2017-05-24

    Density functional theory calculations have been used to investigate the activation mechanism for the precatalyst series [Pd]-X-1–4 derived from [Pd(IPr)(R-allyl)X] species by substitutions at the terminal position of the allyl moiety ([Pd] = Pd(IPr); R = H (1), Me (2), gem-Me2 (3), Ph (4), X = Cl, Br). Next, we have investigated the Suzuki–Miyaura cross-coupling reaction for the active catalyst species IPr-Pd(0) using 4-chlorotoluene and phenylboronic acid as substrates and isopropyl alcohol as a solvent. Our theoretical findings predict an upper barrier trend, corresponding to the activation mechanism for the [Pd]-Cl-1–4 series, in good agreement with the experiments. They indeed provide a quantitative explanation of the low yield (12%) displayed by [Pd]-Cl-1 species (ΔG⧧ ≈ 30.0 kcal/mol) and of the high yields (≈90%) observed in the case of [Pd]-Cl-2–4 complexes (ΔG⧧ ≈ 20.0 kcal/mol). Additionally, the studied Suzuki–Miyaura reaction involving the IPr-Pd(0) species is calculated to be thermodynamically favorable and kinetically facile. Similar investigations for the [Pd]-Br-1–4 series, derived from [Pd(IPr)(R-allyl)Br], indicate that the oxidative addition step for IPr-Pd(0)-mediated catalysis with 4-bromotoluene is kinetically more favored than that with 4-chlorotoluene. Finally, we have explored the potential of Ni-based complexes [Ni((IPr)(R-allyl)X] (X = Cl, Br) as Suzuki–Miyaura reaction catalysts. Apart from a less endergonic reaction energy profile for both precatalyst activation and catalytic cycle, a steep increase in the predicted upper energy barriers (by 2.0–15.0 kcal/mol) is calculated in the activation mechanism for the [Ni]-X-1–4 series compared to the [Pd]-X-1–4 series. Overall, these results suggest that Ni-based precatalysts are expected to be less active than the Pd-based precatalysts for the studied Suzuki–Miyaura reaction.

  9. Efficient and simple production of insulin-producing cells from embryonal carcinoma stem cells using mouse neonate pancreas extract, as a natural inducer.

    Directory of Open Access Journals (Sweden)

    Marzieh Ebrahimie

    Full Text Available An attractive approach to replace the destroyed insulin-producing cells (IPCs is the generation of functional β cells from stem cells. Embryonal carcinoma (EC stem cells are pluripotent cells which can differentiate into all cell types. The present study was carried out to establish a simple nonselective inductive culture system for generation of IPCs from P19 EC cells by 1-2 weeks old mouse pancreas extract (MPE. Since, mouse pancreatic islets undergo further remodeling and maturation for 2-3 weeks after birth, we hypothesized that the mouse neonatal MPE contains essential factors to induce in vitro differentiation of pancreatic lineages. Pluripotency of P19 cells were first confirmed by expression analysis of stem cell markers, Oct3/4, Sox-2 and Nanog. In order to induce differentiation, the cells were cultured in a medium supplemented by different concentrations of MPE (50, 100, 200 and 300 µg/ml. The results showed that P19 cells could differentiate into IPCs and form dithizone-positive cell clusters. The generated P19-derived IPCs were immunoreactive to proinsulin, insulin and insulin receptor beta. The expression of pancreatic β cell genes including, PDX-1, INS1 and INS2 were also confirmed. The peak response at the 100 µg/ml MPE used for investigation of EP300 and CREB1 gene expression. When stimulated with glucose, these cells synthesized and secreted insulin. Network analysis of the key transcription factors (PDX-1, EP300, CREB1 during the generation of IPCs resulted in introduction of novel regulatory candidates such as MIR17, and VEZF1 transcription factors, as well as MORN1, DKFZp761P0212, and WAC proteins. Altogether, we demonstrated the possibility of generating IPCs from undifferentiated EC cells, with the characteristics of pancreatic β cells. The derivation of pancreatic cells from EC cells which are ES cell siblings would provide a valuable experimental tool in study of pancreatic development and function as well as rapid

  10. Approaching to DM2 through sodium-glucose cotransporter-2: does it make sense?

    Science.gov (United States)

    Segura, Julián

    2016-11-01

    The kidney is involved in glucose homeostasis through three main mechanisms: renal gluconeogenesis, renal glucose consumption and glucose reabsorption in the proximal tubule. Glucose reabsorption is one of the most relevant physiological functions of the kidney, through which filtered glucose is fully recovered, urine is free of glucose, and calorie loss is prevented. Approximately 90% of the glucose is reabsorbed in the S1 segment of the proximal tubule, where GLUT2 and SGLT2 transporters are located, while the remaining 10% is reabsorbed in the S3 segment by SGLT1 and GLUT1 transporters. In patients with hyperglycaemia, the kidney continues reabsorbing glucose, and hyperglycaemia is maintained. Most renal glucose reabsorption is mediated by the SGLT2 transporter. Several experimental and clinical studies suggest that pharmacological blockade of this transporter might be beneficial in the management of hyperglycemia in patients with type 2 diabetes. Copyright © 2016 Elsevier España, S.L.U. All rights reserved.

  11. Properties of the reverse transcription reaction in mRNA quantification

    DEFF Research Database (Denmark)

    Ståhlberg, Anders; Håkansson, Joakim; Xian, Xiaojie

    2004-01-01

    BACKGROUND: In most measurements of gene expression, mRNA is first reverse-transcribed into cDNA. We studied the reverse transcription reaction and its consequences for quantitative measurements of gene expression. METHODS: We used SYBR green I-based quantitative real-time PCR (QPCR) to measure...... the properties of reverse transcription reaction for the beta-tubulin, glyceraldehyde-3-phosphate dehydrogenase, Glut2, CaV1D, and insulin II genes, using random hexamers, oligo(dT), and gene-specific reverse transcription primers. RESULTS: Experimental variation in reverse transcription-QPCR (RT......-QPCR) was mainly attributable to the reverse transcription step. Reverse transcription efficiency depended on priming strategy, and the dependence was different for the five genes studied. Reverse transcription yields also depended on total RNA concentration. CONCLUSIONS: RT-QPCR gene expression measurements...

  12. The Role of Genetic Factors in the Outbreak Mechanism of Dental Caries.

    Science.gov (United States)

    Shimomura-Kuroki, Junko; Nashida, Tomoko; Miyagawa, Yukio; Sekimoto, Tsuneo

    The aim of the present study was to investigate the relationships between cariogenic bacterial infection and single nucleotide polymorphisms (SNPs) in candidate genes associated with dental caries, and to explore the factors related to caries in children. Children aged 3 to 11 years were selected. Detection of cariogenic bacteria (Streptococcus mutans, Streptococcus oralis, Streptococcus sobrinus and Lactobacillus) from the plaque of each patient, and SNP analyses of five candidate genes (MBL2, TAS2R38, GLUT2, MMP13 and CA6) were performed using DNA isolated from buccal mucosal cells. The dental caries experience in primary and permanent teeth was determined using the decayed, missing and filled teeth (DMFT) index, and the effects of the observed factors on the DMFT value were analyzed by multiple regression analysis. The results of the multiple regression analysis showed that the DMFT value significantly increased in the presence of S. mutans or S. sobrinus (p caries.

  13. CHEMICAL CHARACTERIZATION OF A HYPOGLYCEMIC EXTRACT FROM CUCURBITA FICIFOLIA BOUCHE THAT INDUCES LIVER GLYCOGEN ACCUMULATION IN DIABETIC MICE.

    Science.gov (United States)

    Jessica, Garcia Gonzalez; Mario, Garcia Lorenzana; Alejandro, Zamilpa; Cesar, Almanza Perez Julio; Ivan, Jasso Villagomez E; Ruben, Roman Ramos; Javier, Alarcon-Aguilar Francisco

    2017-01-01

    The aqueous extract of Cucurbita ficifolia ( C. ficifolia ) fruit has demonstrated hypoglycemic effect, which may be attributed to some components in the extract. However, the major secondary metabolites in this fruit have not yet been identified and little is known about its extra-pancreatic action, in particular, on liver carbohydrate metabolism. Therefore, in addition to the isolation and structural elucidation of the principal components in the aqueous extract of C. ficifolia , the aim of this study was to determine whether or not the hypoglycemic effect of the aqueous extract of Cucurbita ficifolia ( C. ficifolia ) fruit is due to accumulation of liver glycogen in diabetic mice. The aqueous extract from fruit of C. ficifolia was fractionated and its main secondary metabolites were purified and chemically characterized (NMR and GC-MS). Alloxan-induced diabetic mice received daily by gavage the aqueous extract (30 days). The liver glycogen content was quantified by spectroscopic method and by PAS stain; ALT and AST by spectrometric method; glycogen synthase, glycogen phosphorylase and GLUT2 by Western blot; the mRNA expression of GLUT2 and glucagon-receptor by RT-PCR; while serum insulin was quantified by ELISA method. A liver histological analysis was also performed by H&E stain. Chemical fingerprint showed five majoritarian compounds in the aqueous extract of C. ficifolia : p -coumaric acid, p-hydroxybenzoic acid, salicin, stigmast-7,2,2-dien-3-ol and stigmast-7-en-3-ol. The histological analysis showed accumulation of liver glycogen. Also, increased glycogen synthase and decreased glycogen phosphorylase were observed. Interestingly, the histological architecture evidenced a liver-protective effect due the extract. Five compounds were identified in C. ficifolia aqueous extract. The hypoglycemic effect of this extract may be partially explained by liver glycogen accumulation. The bioactive compound responsible for the hypoglycemic effect of this extract will be

  14. Effects of SGLT2 inhibition in human kidney proximal tubular cells--renoprotection in diabetic nephropathy?

    Directory of Open Access Journals (Sweden)

    Usha Panchapakesan

    Full Text Available Sodium/glucose cotransporter 2 (SGLT2 inhibitors are oral hypoglycemic agents used to treat patients with diabetes mellitus. SGLT2 inhibitors block reabsorption of filtered glucose by inhibiting SGLT2, the primary glucose transporter in the proximal tubular cell (PTC, leading to glycosuria and lowering of serum glucose. We examined the renoprotective effects of the SGLT2 inhibitor empagliflozin to determine whether blocking glucose entry into the kidney PTCs reduced the inflammatory and fibrotic responses of the cell to high glucose. We used an in vitro model of human PTCs. HK2 cells (human kidney PTC line were exposed to control 5 mM, high glucose (HG 30 mM or the profibrotic cytokine transforming growth factor beta (TGFβ1; 0.5 ng/ml in the presence and absence of empagliflozin for up to 72 h. SGLT1 and 2 expression and various inflammatory/fibrotic markers were assessed. A chromatin immunoprecipitation assay was used to determine the binding of phosphorylated smad3 to the promoter region of the SGLT2 gene. Our data showed that TGFβ1 but not HG increased SGLT2 expression and this occurred via phosphorylated smad3. HG induced expression of Toll-like receptor-4, increased nuclear deoxyribonucleic acid binding for nuclear factor kappa B (NF-κB and activator protein 1, induced collagen IV expression as well as interleukin-6 secretion all of which were attenuated with empagliflozin. Empagliflozin did not reduce high mobility group box protein 1 induced NF-κB suggesting that its effect is specifically related to a reduction in glycotoxicity. SGLT1 and GLUT2 expression was not significantly altered with HG or empagliflozin. In conclusion, empagliflozin reduces HG induced inflammatory and fibrotic markers by blocking glucose transport and did not induce a compensatory increase in SGLT1/GLUT2 expression. Although HG itself does not regulate SGLT2 expression in our model, TGFβ increases SGLT2 expression through phosphorylated smad3.

  15. Natural Products as Lead Compounds for Sodium Glucose Cotransporter (SGLT) Inhibitors.

    Science.gov (United States)

    Blaschek, Wolfgang

    2017-08-01

    Glucose homeostasis is maintained by antagonistic hormones such as insulin and glucagon as well as by regulation of glucose absorption, gluconeogenesis, biosynthesis and mobilization of glycogen, glucose consumption in all tissues and glomerular filtration, and reabsorption of glucose in the kidneys. Glucose enters or leaves cells mainly with the help of two membrane integrated transporters belonging either to the family of facilitative glucose transporters (GLUTs) or to the family of sodium glucose cotransporters (SGLTs). The intestinal glucose absorption by endothelial cells is managed by SGLT1, the transfer from them to the blood by GLUT2. In the kidney SGLT2 and SGLT1 are responsible for reabsorption of filtered glucose from the primary urine, and GLUT2 and GLUT1 enable the transport of glucose from epithelial cells back into the blood stream.The flavonoid phlorizin was isolated from the bark of apple trees and shown to cause glucosuria. Phlorizin is an inhibitor of SGLT1 and SGLT2. With phlorizin as lead compound, specific inhibitors of SGLT2 were developed in the last decade and some of them have been approved for treatment mainly of type 2 diabetes. Inhibition of SGLT2 eliminates excess glucose via the urine. In recent times, the dual SGLT1/SGLT2 inhibitory activity of phlorizin has served as a model for the development and testing of new drugs exhibiting both activities.Besides phlorizin, also some other flavonoids and especially flavonoid enriched plant extracts have been investigated for their potency to reduce postprandial blood glucose levels which can be helpful in the prevention and supplementary treatment especially of type 2 diabetes. Georg Thieme Verlag KG Stuttgart · New York.

  16. Effects of exogenous glucagon-like peptide-2 and distal bowel resection on intestinal and systemic adaptive responses in rats.

    Science.gov (United States)

    Lai, Sarah W; de Heuvel, Elaine; Wallace, Laurie E; Hartmann, Bolette; Holst, Jens J; Brindle, Mary E; Chelikani, Prasanth K; Sigalet, David L

    2017-01-01

    To determine the effects of exogenous glucagon-like peptide-2 (GLP-2), with or without massive distal bowel resection, on adaptation of jejunal mucosa, enteric neurons, gut hormones and tissue reserves in rats. GLP-2 is a gut hormone known to be trophic for small bowel mucosa, and to mimic intestinal adaptation in short bowel syndrome (SBS). However, the effects of exogenous GLP-2 and SBS on enteric neurons are unclear. Sprague Dawley rats were randomized to four treatments: Transected Bowel (TB) (n = 8), TB + GLP-2 (2.5 nmol/kg/h, n = 8), SBS (n = 5), or SBS + GLP-2 (2.5 nmol/kg/h, n = 9). SBS groups underwent a 60% jejunoileal resection with cecectomy and jejunocolic anastomosis. All rats were maintained on parenteral nutrition for 7 d. Parameters measured included gut morphometry, qPCR for hexose transporter (SGLT-1, GLUT-2, GLUT-5) and GLP-2 receptor mRNA, whole mount immunohistochemistry for neurons (HuC/D, VIP, nNOS), plasma glucose, gut hormones, and body composition. Resection increased the proportion of nNOS immunopositive myenteric neurons, intestinal muscularis propria thickness and crypt cell proliferation, which were not recapitulated by GLP-2 therapy. Exogenous GLP-2 increased jejunal mucosal surface area without affecting enteric VIP or nNOS neuronal immunopositivity, attenuated resection-induced reductions in jejunal hexose transporter abundance (SGLT-1, GLUT-2), increased plasma amylin and decreased peptide YY concentrations. Exogenous GLP-2 attenuated resection-induced increases in blood glucose and body fat loss. Exogenous GLP-2 stimulates jejunal adaptation independent of enteric neuronal VIP or nNOS changes, and has divergent effects on plasma amylin and peptide YY concentrations. The novel ability of exogenous GLP-2 to modulate resection-induced changes in peripheral glucose and lipid reserves may be important in understanding the whole-body response following intestinal resection, and is worthy of further study.

  17. Effects of exogenous glucagon-like peptide-2 and distal bowel resection on intestinal and systemic adaptive responses in rats.

    Directory of Open Access Journals (Sweden)

    Sarah W Lai

    Full Text Available To determine the effects of exogenous glucagon-like peptide-2 (GLP-2, with or without massive distal bowel resection, on adaptation of jejunal mucosa, enteric neurons, gut hormones and tissue reserves in rats.GLP-2 is a gut hormone known to be trophic for small bowel mucosa, and to mimic intestinal adaptation in short bowel syndrome (SBS. However, the effects of exogenous GLP-2 and SBS on enteric neurons are unclear.Sprague Dawley rats were randomized to four treatments: Transected Bowel (TB (n = 8, TB + GLP-2 (2.5 nmol/kg/h, n = 8, SBS (n = 5, or SBS + GLP-2 (2.5 nmol/kg/h, n = 9. SBS groups underwent a 60% jejunoileal resection with cecectomy and jejunocolic anastomosis. All rats were maintained on parenteral nutrition for 7 d. Parameters measured included gut morphometry, qPCR for hexose transporter (SGLT-1, GLUT-2, GLUT-5 and GLP-2 receptor mRNA, whole mount immunohistochemistry for neurons (HuC/D, VIP, nNOS, plasma glucose, gut hormones, and body composition.Resection increased the proportion of nNOS immunopositive myenteric neurons, intestinal muscularis propria thickness and crypt cell proliferation, which were not recapitulated by GLP-2 therapy. Exogenous GLP-2 increased jejunal mucosal surface area without affecting enteric VIP or nNOS neuronal immunopositivity, attenuated resection-induced reductions in jejunal hexose transporter abundance (SGLT-1, GLUT-2, increased plasma amylin and decreased peptide YY concentrations. Exogenous GLP-2 attenuated resection-induced increases in blood glucose and body fat loss.Exogenous GLP-2 stimulates jejunal adaptation independent of enteric neuronal VIP or nNOS changes, and has divergent effects on plasma amylin and peptide YY concentrations. The novel ability of exogenous GLP-2 to modulate resection-induced changes in peripheral glucose and lipid reserves may be important in understanding the whole-body response following intestinal resection, and is worthy of further study.

  18. Molecular factors involved in the hypolipidemic- and insulin-sensitizing effects of a ginger (Zingiber officinale Roscoe) extract in rats fed a high-fat diet.

    Science.gov (United States)

    de Las Heras, Natalia; Valero-Muñoz, María; Martín-Fernández, Beatriz; Ballesteros, Sandra; López-Farré, Antonio; Ruiz-Roso, Baltasar; Lahera, Vicente

    2017-02-01

    Hypolipidemic and hypoglycemic properties of ginger in animal models have been reported. However, information related to the mechanisms and factors involved in the metabolic effects of ginger at a hepatic level are limited. The aim of the present study was to investigate molecular factors involved in the hypoglycemic and hypolipidemic effects of a hydroethanolic ginger extract (GE) in the liver of rats fed a high-fat diet (HFD). The study was conducted in male Wistar rats divided into the following 3 groups: (i) Rats fed a standard diet (3.5% fat), the control group; (ii) rats fed an HFD (33.5% fat); and (iii) rats fed an HFD treated with GE (250 mg·kg -1 ·day -1 ) for 5 weeks (HFD+GE). Plasma levels of glucose, insulin, lipid profile, leptin, and adiponectin were measured. Liver expression of glycerol phosphate acyltransferase (GPAT), cholesterol 7 alpha-hydroxylase, peroxisome proliferator-activated receptors (PPAR), PPARα and PPARγ, glucose transporter 2 (GLUT-2), liver X receptor, sterol regulatory element-binding protein (SREBP1c), connective tissue growth factor (CTGF), and collagen I was measured. Data were analyzed using a 1-way ANOVA, followed by a Newman-Keuls test if differences were noted. The study showed that GE improved lipid profile and attenuated the increase of plasma levels of glucose, insulin, and leptin in HFD rats. This effect was associated with a higher liver expression of PPARα, PPARγ, and GLUT-2 and an enhancement of plasma adiponectin levels. Furthermore, GE reduced liver expression of GPAT, SREBP1c, CTGF, and collagen I. The results suggest that GE might be considered as an alternative therapeutic strategy in the management of overweight and hepatic and metabolic-related alterations.

  19. Psidium guajava Linn. leaf extract affects hepatic glucose transporter-2 to attenuate early onset of insulin resistance consequent to high fructose intake: An experimental study

    Science.gov (United States)

    Mathur, R.; Dutta, Shagun; Velpandian, T.; Mathur, S.R.

    2015-01-01

    Background: Insulin resistance (IR) is amalgam of pathologies like altered glucos metabolism, dyslipidemia, impaired glucose tolerance, non-alcoholic fatty liver disease, and associated with type-II diabetes and cardiometabolic diseases. One of the reasons leading to its increased and early incidence is understood to be a high intake of processed fructose containing foods and beverages by individuals, especially, during critical developmental years. Objective: To investigate the preventive potential of aqueous extract of Psidium guajava leaves (PG) against metabolic pathologies, vis-à-vis, IR, dyslipidemia, hyperleptinemia and hypertension, due to excess fructose intake initiated during developmental years. Materials and Methods: Post-weaning (4 weeks old) male rats were provided fructose (15%) as drinking solution, ad libitum, for 8 weeks and assessed for food and water/fructose intake, body weight, fasting blood sugar, mean arterial pressure, lipid biochemistry, endocrinal (insulin, leptin), histopathological (fatty liver) and immunohistochemical (hepatic glucose transporter [GLUT2]) parameters. Parallel treatment groups were administered PG in doses of 250 and 500 mg/kg/d, po × 8 weeks and assessed for same parameters. Using extensive liquid chromatography-mass spectrometry protocols, PG was analyzed for the presence of phytoconstituents like Myrecetin, Luteolin, Kaempferol and Guavanoic acid and validated to contain Quercetin up to 9.9%w/w. Results: High fructose intake raised circulating levels of insulin and leptin and hepatic GLUT2 expression to promote IR, dyslipidemia, and hypertension that were favorably re-set with PG. Although PG is known for its beneficial role in diabetes mellitus, for the first time we report its potential in the management of lifelong pathologies arising from high fructose intake initiated during developmental years. PMID:25829790

  20. Selection for high muscle fat in rainbow trout induces potentially higher chylomicron synthesis and PUFA biosynthesis in the intestine.

    Science.gov (United States)

    Kamalam, Biju Sam; Panserat, Stephane; Aguirre, Peyo; Geurden, Inge; Fontagné-Dicharry, Stéphanie; Médale, Françoise

    2013-02-01

    Two lines of rainbow trout divergently selected for muscle fat content, fat line (F) and lean line (L) were used to investigate the effect of genetic selection on digestion, intestinal nutrient transport and fatty acid bioconversion, in relation to dietary starch intake. This study involved a digestibility trial for 2 weeks using Cr(2)O(3) as inert marker, followed by a feeding trial for 4 weeks. For the entire duration, juvenile trout from the two lines were fed diets with or without gelatinized starch. Blood, pyloric ceca, midgut and hindgut were sampled at 24 h after the last meal. Transcripts of the proteins involved in nutrient transport and fatty acid bioconversion were abundant in the proximal intestine. GLUT2 transcripts were slightly higher in the F line ceca than in the L line. Dietary starch intake did not enhance the transcription of intestinal glucose transporters, SGLT1 and GLUT2; but it was associated with the higher expression of ApoA1 and PepT1 in the midgut. Significantly, the F line exhibited higher intestinal mRNA levels of MTP, ApoA4, Elovl2, Elovl5 and D6D than the L line, linked to chylomicron assembly and fatty acid bioconversion. Apparent digestibility coefficients of protein, lipid and starch were high in both lines, but not significantly different between them. In conclusion, we found a higher potential of chylomicron synthesis and fatty acid bioconversion in the intestine of F line, but no adaptive transcriptional response of glucose transporters to dietary starch and no genotypic differences in nutrient digestibility. Copyright © 2012 Elsevier Inc. All rights reserved.

  1. Effects of Steaming Time and Frequency for Manufactured Red Liriope platyphylla on the Insulin Secretion Ability and Insulin Receptor Signaling Pathway.

    Science.gov (United States)

    Choi, Sun Il; Lee, Hye Ryun; Goo, Jun Seo; Kim, Ji Eun; Nam, So Hee; Hwang, In Sik; Lee, Young Ju; Prak, So Hae; Lee, Hee Seob; Lee, Jong Sup; Jang, In Surk; Son, Hong Ju; Hwang, Dae Youn

    2011-06-01

    In oriental medicine, Liriope platyphylla (LP) has long been regarded as a curative herb useful for the treatment of diabetes, asthma, and neurodegenerative disorders. The principal objective of this study was to assess the effects of steaming time and frequency for manufactured Red LP (RLP) on insulin secretion ability and insulin receptor signaling pathway. To achieve our goal, several types of LPs manufactured under different conditions were applied to INS cells and streptozotocin (STZ)-induced diabetic ICR mice, after which alterations in insulin concentrations were detected in the culture supernatants and sera. The optimal concentration for the investigation of insulin secretion ability was found to be 50 ug/mL of LP. At this concentration, maximum insulin secretion was observed in the INS cells treated with LP extract steamed for 3 h (3-SLP) with two repeated steps (3 h steaming and 24 h air-dried) carried out 9 times (9-SALP); no significant changes in viability were detected in any of the treated cells. Additionally, the expression and phosphorylation levels of most components in the insulin receptor signaling pathway were increased significantly in the majority of cells treated with steaming-processed LP as compared to the cells treated with LP prepared without steaming. With regard to glucose transporter (GLUT) expression, alterations of steaming time induced similar responses on the expression levels of GLUT-2 and GLUT-3. However, differences in steaming frequency were also shown to induce dose-dependent responses in the expression level of GLUT-2 only; no significant differences in GLUT-3 expression were detected under these conditions. Furthermore, these responses observed in vitro were similarly detected in STZ-induced diabetic mice. 24-SLP and 9-SALP treatment applied for 14 days induced the down-regulation of glucose concentration and upregulation of insulin concentration. Therefore, these results indicated that the steaming processed LP may

  2. Effects of exogenous glucagon-like peptide-2 and distal bowel resection on intestinal and systemic adaptive responses in rats

    Science.gov (United States)

    de Heuvel, Elaine; Wallace, Laurie E.; Hartmann, Bolette; Holst, Jens J.; Brindle, Mary E.; Chelikani, Prasanth K.; Sigalet, David L.

    2017-01-01

    Objective To determine the effects of exogenous glucagon-like peptide-2 (GLP-2), with or without massive distal bowel resection, on adaptation of jejunal mucosa, enteric neurons, gut hormones and tissue reserves in rats. Background GLP-2 is a gut hormone known to be trophic for small bowel mucosa, and to mimic intestinal adaptation in short bowel syndrome (SBS). However, the effects of exogenous GLP-2 and SBS on enteric neurons are unclear. Methods Sprague Dawley rats were randomized to four treatments: Transected Bowel (TB) (n = 8), TB + GLP-2 (2.5 nmol/kg/h, n = 8), SBS (n = 5), or SBS + GLP-2 (2.5 nmol/kg/h, n = 9). SBS groups underwent a 60% jejunoileal resection with cecectomy and jejunocolic anastomosis. All rats were maintained on parenteral nutrition for 7 d. Parameters measured included gut morphometry, qPCR for hexose transporter (SGLT-1, GLUT-2, GLUT-5) and GLP-2 receptor mRNA, whole mount immunohistochemistry for neurons (HuC/D, VIP, nNOS), plasma glucose, gut hormones, and body composition. Results Resection increased the proportion of nNOS immunopositive myenteric neurons, intestinal muscularis propria thickness and crypt cell proliferation, which were not recapitulated by GLP-2 therapy. Exogenous GLP-2 increased jejunal mucosal surface area without affecting enteric VIP or nNOS neuronal immunopositivity, attenuated resection-induced reductions in jejunal hexose transporter abundance (SGLT-1, GLUT-2), increased plasma amylin and decreased peptide YY concentrations. Exogenous GLP-2 attenuated resection-induced increases in blood glucose and body fat loss. Conclusions Exogenous GLP-2 stimulates jejunal adaptation independent of enteric neuronal VIP or nNOS changes, and has divergent effects on plasma amylin and peptide YY concentrations. The novel ability of exogenous GLP-2 to modulate resection-induced changes in peripheral glucose and lipid reserves may be important in understanding the whole-body response following intestinal resection, and is worthy

  3. Detection of transketolase in bone marrow-derived insulin-producing cells: benfotiamine enhances insulin synthesis and glucose metabolism.

    Science.gov (United States)

    Oh, Seh-Hoon; Witek, Rafal P; Bae, Si-Hyun; Darwiche, Houda; Jung, Youngmi; Pi, Liya; Brown, Alicia; Petersen, Bryon E

    2009-01-01

    Adult bone marrow (BM)-derived insulin-producing cells (IPCs) are capable of regulating blood glucose levels in chemically induced hyperglycemic mice. Using cell transplantation therapy, fully functional BM-derived IPCs help to mediate treatment of diabetes mellitus. Here, we demonstrate the detection of the pentose phosphate pathway enzyme, transketolase (TK), in BM-derived IPCs cultured under high-glucose conditions. Benfotiamine, a known activator of TK, was not shown to affect the proliferation of insulinoma cell line, INS-1; however, when INS-1 cells were cultured with oxythiamine, an inhibitor of TK, cell proliferation was suppressed. Treatment with benfotiamine activated glucose metabolism in INS-1 cells in high-glucose culture conditions, and appeared to maximize the BM-derived IPCs ability to synthesize insulin. Benfotiamine was not shown to induce the glucose receptor Glut-2, however it was shown to activate glucokinase, the enzyme responsible for conversion of glucose to glucose-6-phosphate. Furthermore, benfotiamine-treated groups showed upregulation of the downstream glycolytic enzyme, glyceraldehyde phosphate dehydrogenase (GAPDH). However, in cells where the pentose phosphate pathway was blocked by oxythiamine treatment, there was a clear downregulation of Glut-2, glucokinase, insulin, and GAPDH. When benfotiamine was used to treat mice transplanted with BM-derived IPCs transplanted, their glucose level was brought to a normal range. The glucose challenge of normal mice treated with benfotiamine lead to rapidly normalized blood glucose levels. These results indicate that benfotiamine activates glucose metabolism and insulin synthesis to prevent glucose toxicity caused by high concentrations of blood glucose in diabetes mellitus.

  4. Detection of Transketolase in Bone Marrow—Derived Insulin-Producing Cells: Benfotiamine Enhances Insulin Synthesis and Glucose Metabolism

    Science.gov (United States)

    Witek, Rafal P.; Bae, Si-Hyun; Darwiche, Houda; Jung, Youngmi; Pi, Liya; Brown, Alicia; Petersen, Bryon E.

    2009-01-01

    Adult bone marrow (BM)-derived insulin-producing cells (IPCs) are capable of regulating blood glucose levels in chemically induced hyperglycemic mice. Using cell transplantation therapy, fully functional BM-derived IPCs help to mediate treatment of diabetes mellitus. Here, we demonstrate the detection of the pentose phosphate pathway enzyme, transketolase (TK), in BM-derived IPCs cultured under high-glucose conditions. Benfotiamine, a known activator of TK, was not shown to affect the proliferation of insulinoma cell line, INS-1; however, when INS-1 cells were cultured with oxythiamine, an inhibitor of TK, cell proliferation was suppressed. Treatment with benfotiamine activated glucose metabolism in INS-1 cells in high-glucose culture conditions, and appeared to maximize the BM-derived IPCs ability to synthesize insulin. Benfotiamine was not shown to induce the glucose receptor Glut-2, however it was shown to activate glucokinase, the enzyme responsible for conversion of glucose to glucose-6-phosphate. Furthermore, benfotiamine-treated groups showed upregulation of the downstream glycolytic enzyme, glyceraldehyde phosphate dehydrogenase (GAPDH). However, in cells where the pentose phosphate pathway was blocked by oxythiamine treatment, there was a clear downregulation of Glut-2, glucokinase, insulin, and GAPDH. When benfotiamine was used to treat mice transplanted with BM-derived IPCs transplanted, their glucose level was brought to a normal range. The glucose challenge of normal mice treated with benfotiamine lead to rapidly normalized blood glucose levels. These results indicate that benfotiamine activates glucose metabolism and insulin synthesis to prevent glucose toxicity caused by high concentrations of blood glucose in diabetes mellitus. PMID:18393672

  5. Regulation of epithelial differentiation in rat intestine by intraluminal delivery of an adenoviral vector or silencing RNA coding for Schlafen 3.

    Directory of Open Access Journals (Sweden)

    Pavlo L Kovalenko

    Full Text Available Although we stimulate enterocytic proliferation to ameliorate short gut syndrome or mucosal atrophy, less effort has been directed at enterocytic differentiation. Schlafen 3 (Slfn3 is a poorly understood protein induced during IEC-6 enterocytic differentiation. We hypothesized that exogenous manipulation of Slfn3 would regulate enterocytic differentiation in vivo. Adenoviral vector coding for Slfn3 cDNA (Ad-GFP-Slfn3 or silencing RNA for Slfn3 (siSlfn3 was introduced intraluminally into rat intestine. We assessed Slfn3, villin, sucrase-isomaltase (SI, Dpp4, and Glut2 by qRT-PCR, Western blot, and immunohistochemistry. We also studied Slfn3 and these differentiation markers in atrophic defunctionalized jejunal mucosa and the crypt-villus axis of normal jejunum. Ad-GFP-Slfn3 but not Ad-GFP increased Slfn3, villin and Dpp4 expression in human Caco-2 intestinal epithelial cells. Injecting Ad-GFP-Slfn3 into rat jejunum in vivo increased mucosal Slfn3 mRNA three days later vs. intraluminal Ad-GFP. This Slfn3 overexpression was associated with increases in all four differentiation markers. Injecting siSlfn3 into rat jejunum in vivo substantially reduced Slfn3 and all four intestinal mucosal differentiation markers three days later, as well as Dpp4 specific activity. Endogenous Slfn3 was reduced in atrophic mucosa from a blind-end Roux-en-Y anastomosis in parallel with differentiation marker expression together with AKT and p38 signaling. Slfn3 was more highly expressed in the villi than the crypts, paralleling Glut2, SI and Dpp4. Slfn3 is a key intracellular regulator of rat enterocytic differentiation. Understanding how Slfn3 works may identify targets to promote enterocytic differentiation and maintain mucosal function in vivo, facilitating enteral nutrition and improving survival in patients with mucosal atrophy or short gut syndrome.

  6. Increased glucose metabolism and alpha-glucosidase inhibition in Cordyceps militaris water extract-treated HepG2 cells

    Science.gov (United States)

    Kim, Dae Jung; Kang, Yun Hwan; Kim, Kyoung Kon; Kim, Tae Woo; Park, Jae Bong

    2017-01-01

    BACKGROUND/OBJECTIVES Recent living condition improvements, changes in dietary habits, and reductions in physical activity are contributing to an increase in metabolic syndrome symptoms including diabetes and obesity. Through such societal developments, humankind is continuously exposed to metabolic diseases such as diabetes, and the number of the victims is increasing. This study investigated Cordyceps militaris water extract (CMW)-induced glucose uptake in HepG2 cells and the effect of CMW treatment on glucose metabolism. MATERIALS/METHODS Colorimetric assay kits were used to determine the glucokinase (GK) and pyruvate dehydrogenase (PDH) activities, glucose uptake, and glycogen content. Either RT-PCR or western blot analysis was performed for quantitation of glucose transporter 2 (GLUT2), hepatocyte nuclear factor 1 alpha (HNF-1α), phosphatidylinositol 3-kinase (PI3k), protein kinase B (Akt), phosphorylated AMP-activated protein kinase (pAMPK), phosphoenolpyruvate carboxykinase, GK, PDH, and glycogen synthase kinase 3 beta (GSK-3β) expression levels. The α-glucosidase inhibitory activities of acarbose and CMW were evaluated by absorbance measurement. RESULTS CMW induced glucose uptake in HepG2 cells by increasing GLUT2 through HNF-1α expression stimulation. Glucose in the cells increased the CMW-induced phosphorylation of AMPK. In turn, glycolysis was stimulated, and glyconeogenesis was inhibited. Furthermore, by studying the mechanism of action of PI3k, Akt, and GSK-3β, and measuring glycogen content, the study confirmed that the glucose was stored in the liver as glycogen. Finally, CMW resulted in a higher level of α-glucosidase inhibitory activity than that from acarbose. CONCLUSION CMW induced the uptake of glucose into HepG2 cells, as well, it induced metabolism of the absorbed glucose. It is concluded that CMW is a candidate or potential use in diabetes prevention and treatment. PMID:28584574

  7. Decreased serum glucose and glycosylated hemoglobin levels in patients with Chuvash polycythemia: a role for HIF in glucose metabolism

    Science.gov (United States)

    McClain, Donald A.; Abuelgasim, Khadega A.; Nouraie, Mehdi; Salomon-Andonie, Juan; Niu, Xiaomei; Miasnikova, Galina; Polyakova, Lydia A.; Sergueeva, Adelina; Okhotin, Daniel J.; Cherqaoui, Rabia; Okhotin, David; Cox, James E.; Swierczek, Sabina; Song, Jihyun; Simon, M.Celeste; Huang, Jingyu; Simcox, Judith A.; Yoon, Donghoon; Prchal, Josef T.; Gordeuk, Victor R.

    2012-01-01

    In Chuvash polycythemia, a homozygous 598C>T mutation in the von Hippel-Lindau gene (VHL) leads to an R200W substitution in VHL protein, impaired degradation of α-subunits of hypoxia inducible factor (HIF)-1 and HIF-2, and augmented hypoxic responses during normoxia. Chronic hypoxia of high altitude is associated with decreased serum glucose and insulin concentrations. Other investigators reported that HIF-1 promotes cellular glucose uptake by increased expression of GLUT1 and increased glycolysis by increased expression of enzymes such as PDK. On the other hand, inactivation of Vhl in murine liver leads to hypoglycemia associated with a HIF-2-related decrease in the expression of the gluconeogenic enzymes genes Pepck, G6pc, and Glut2. We therefore hypothesized that glucose concentrations are decreased in individuals with Chuvash polycythemia. We found that 88 Chuvash VHLR200W homozygotes had lower random glucose and glycosylated hemoglobin A1c levels than 52 Chuvash subjects with wildtype VHL alleles. Serum metabolomics revealed higher glycerol and citrate levels in the VHLR200W homozygotes. We expanded these observations in VHLR200W homozygote mice and found that they had lower fasting glucose values and lower glucose excursions than wild-type control mice but no change in fasting insulin concentrations. Hepatic expression of Glut2 and G6pc but not Pdk2 was decreased and skeletal muscle expression of Glut1, Pdk1 and Pdk4 was increased. These results suggest that both decreased hepatic gluconeogenesis and increased skeletal uptake and glycolysis contribute to the decreased glucose concentrations. Further study is needed to determine whether pharmacologically manipulating HIF expression might be beneficial for treatment of diabetic patients. PMID:23015148

  8. Leptin modulates human Sertoli cells acetate production and glycolytic profile: a novel mechanism of obesity-induced male infertility?

    Science.gov (United States)

    Martins, Ana D; Moreira, Ana C; Sá, Rosália; Monteiro, Mariana P; Sousa, Mário; Carvalho, Rui A; Silva, Branca M; Oliveira, Pedro F; Alves, Marco G

    2015-09-01

    Human feeding behavior and lifestyle are gradually being altered, favoring the development of metabolic diseases, particularly type 2 diabetes and obesity. Leptin is produced by the adipose tissue acting as a satiety signal. Its levels have been positively correlated with fat mass and hyperleptinemia has been proposed to negatively affect male reproductive function. Nevertheless, the molecular mechanisms by which this hormone affects male fertility remain unknown. Herein, we hypothesize that leptin acts on human Sertoli cells (hSCs), the "nurse cells" of spermatogenesis, altering their metabolism. To test our hypothesis, hSCs were cultured without or with leptin (5, 25 and 50ng/mL). Leptin receptor was identified by qPCR and Western blot. Protein levels of glucose transporters (GLUT1, GLUT2 and GLUT3), phosphofructokinase, lactate dehydrogenase (LDH) and monocarboxylate transporter 4 (MCT4) were determined by Western Blot. LDH activity was assessed and metabolite production/consumption determined by proton nuclear magnetic resonance. Oxidative damage was evaluated by assessing lipid peroxidation, protein carbonilation and nitration. Our data shows that leptin receptor is expressed in hSCs. The concentration of leptin found in lean, healthy patients, upregulated GLUT2 protein levels and concentrations of leptin found in lean and obese patients increased LDH activity. Of note, all leptin concentrations decreased hSCs acetate production illustrating a novel mechanism for this hormone action. Moreover, our data shows that leptin does not induce or protect hSCs from oxidative damage. We report that this hormone modulates the nutritional support of spermatogenesis, illustrating a novel mechanism that may be linked to obesity-induced male infertility. Copyright © 2015 Elsevier B.V. All rights reserved.

  9. Effects of Ursolic Acid Derivatives on Caco-2 Cells and Their Alleviating Role in Streptozocin-Induced Type 2 Diabetic Rats

    Directory of Open Access Journals (Sweden)

    Panpan Wu

    2014-08-01

    Full Text Available In this study, the effect and mechanism of a series of ursolic acid (UA derivatives on glucose uptake were investigated in a Caco-2 cells model. Their effect on hyperglycemia, hyperlipidemia and oxidative stress were also demonstrated in streptozocin (STZ-induced diabetic rats. 2-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-ylamino]-2-deoxy-glucose (2-NBDG was used as a fluorescein in Caco-2 cells model to screen UA derivatives by glucose uptake and expression of glucose transporter protein (SGLT-1, GLUT-2. Moreover, STZ-induced diabetic rats were administered with these derivatives for 4 weeks of treatment. The fasting blood glucose (FBG, insulin levels, biochemical parameters, lipid levels, and oxidative stress markers were finally evaluated. The results of this study indicated that compounds 10 and 11 significantly inhibited 2-NBDG uptake under both Na+-dependent and Na+-independent conditions by decreasing SGLT-1 and GLUT-2 expression in the Caco-2 cells model. Further in vivo studies revealed that compound 10 significantly reduced hyperglycemia by increasing levels of serum insulin, total protein, and albumin, while the fasting blood glucose, body weight and food intake were restored much closer to those of normal rats. Compounds 10 and 11 showed hypolipidemic activity by decreasing the total amounts of cholesterol (TC and triglycerides (TG. Furthermore, compound 10 showed antioxidant potential which was confirmed by elevation of glutathione (GSH and superoxide dismutase (SOD and reduction of malondialdehyde (MDA levels in the liver and kidney of diabetic rats. It was concluded that compound 10 caused an apparent inhibition of intestinal glucose uptake in Caco-2 cells and hypoglycemia, hypolipidemia and augmented oxidative stress in STZ-induced diabetic rats. Thus, compound 10 could be developed as a potentially complementary therapeutic or prophylactic agent for diabetics mellitus and its complications.

  10. Increased oxidative stress and apoptosis in the hypothalamus of diabetic male mice in the insulin receptor substrate-2 knockout model

    Science.gov (United States)

    Canelles, Sandra; Argente, Jesús; Barrios, Vicente

    2016-01-01

    ABSTRACT Insulin receptor substrate-2-deficient (IRS2−/−) mice are considered a good model to study the development of diabetes because IRS proteins mediate the pleiotropic effects of insulin-like growth factor-I (IGF-I) and insulin on metabolism, mitogenesis and cell survival. The hypothalamus might play a key role in the early onset of diabetes, owing to its involvement in the control of glucose homeostasis and energy balance. Because some inflammatory markers are elevated in the hypothalamus of diabetic IRS2−/− mice, our aim was to analyze whether the diabetes associated with the absence of IRS2 results in hypothalamic injury and to analyze the intracellular mechanisms involved. Only diabetic IRS2−/− mice showed increased cell death and activation of caspase-8 and -3 in the hypothalamus. Regulators of apoptosis such as FADD, Bcl-2, Bcl-xL and p53 were also increased, whereas p-IκB and c-FLIPL were decreased. This was accompanied by increased levels of Nox-4 and catalase, enzymes involved in oxidative stress. In summary, the hypothalamus of diabetic IRS2−/− mice showed an increase in oxidative stress and inflammatory markers that finally resulted in cell death via substantial activation of the extrinsic apoptotic pathway. Conversely, non-diabetic IRS2−/− mice did not show cell death in the hypothalamus, possibly owing to an increase in the levels of circulating IGF-I and in the enhanced hypothalamic IGF-IR phosphorylation that would lead to the stimulation of survival pathways. In conclusion, diabetes in IRS2-deficient male mice is associated with increased oxidative stress and apoptosis in the hypothalamus. PMID:27013528

  11. DNA methylation of candidate genes in peripheral blood from patients with type 2 diabetes or the metabolic syndrome.

    Science.gov (United States)

    van Otterdijk, Sanne D; Binder, Alexandra M; Szarc Vel Szic, Katarzyna; Schwald, Julia; Michels, Karin B

    2017-01-01

    The prevalence of type 2 diabetes (T2D) and the metabolic syndrome (MetS) is increasing and several studies suggested an involvement of DNA methylation in the development of these metabolic diseases. This study was designed to investigate if differential DNA methylation in blood can function as a biomarker for T2D and/or MetS. Pyrosequencing analyses were performed for the candidate genes KCNJ11, PPARγ, PDK4, KCNQ1, SCD1, PDX1, FTO and PEG3 in peripheral blood leukocytes (PBLs) from 25 patients diagnosed with only T2D, 9 patients diagnosed with T2D and MetS and 11 control subjects without any metabolic disorders. No significant differences in gene-specific methylation between patients and controls were observed, although a trend towards significance was observed for PEG3. Differential methylation was observed between the groups in 4 out of the 42 single CpG loci located in the promoters regions of the genes FTO, KCNJ11, PPARγ and PDK4. A trend towards a positive correlation was observed for PEG3 methylation with HDL cholesterol levels. Altered levels of DNA methylation in PBLs of specific loci might serve as a biomarker for T2D or MetS, although further investigation is required.

  12. Sirtuin 1 stimulates the proliferation and the expression of glycolysis genes in pancreatic neoplastic lesions.

    Science.gov (United States)

    Pinho, Andreia V; Mawson, Amanda; Gill, Anthony; Arshi, Mehreen; Warmerdam, Max; Giry-Laterriere, Marc; Eling, Nils; Lie, Triyana; Kuster, Evelyne; Camargo, Simone; Biankin, Andrew V; Wu, Jianmin; Rooman, Ilse

    2016-11-15

    Metabolic reprogramming is a feature of neoplasia and tumor growth. Sirtuin 1 (SIRT1) is a lysine deacetylase of multiple targets including metabolic regulators such as p53. SIRT1 regulates metaplasia in the pancreas. Nevertheless, it is unclear if SIRT1 affects the development of neoplastic lesions and whether metabolic gene expression is altered.To assess neoplastic lesion development, mice with a pancreas-specific loss of Sirt1 (Pdx1-Cre;Sirt1-lox) were bred into a KrasG12D mutant background (KC) that predisposes to the development of pancreatic intra-epithelial neoplasia (PanIN) and ductal adenocarcinoma (PDAC). Similar grade PanIN lesions developed in KC and KC;Sirt1-lox mice but specifically early mucinous PanINs occupied 40% less area in the KC;Sirt1-lox line, attributed to reduced proliferation. This was accompanied by reduced expression of proteins in the glycolysis pathway, such as GLUT1 and GAPDH.The stimulatory effect of SIRT1 on proliferation and glycolysis gene expression was confirmed in a human PDAC cell line. In resected PDAC samples, higher proliferation and expression of glycolysis genes correlated with poor patient survival. SIRT1 expression per se was not prognostic but low expression of Cell Cycle and Apoptosis Regulator 2 (CCAR2), a reported SIRT1 inhibitor, corresponded to poor patient survival.These findings open perspectives for novel targeted therapies in pancreatic cancer.

  13. Genomic analyses identify molecular subtypes of pancreatic cancer.

    Science.gov (United States)

    Bailey, Peter; Chang, David K; Nones, Katia; Johns, Amber L; Patch, Ann-Marie; Gingras, Marie-Claude; Miller, David K; Christ, Angelika N; Bruxner, Tim J C; Quinn, Michael C; Nourse, Craig; Murtaugh, L Charles; Harliwong, Ivon; Idrisoglu, Senel; Manning, Suzanne; Nourbakhsh, Ehsan; Wani, Shivangi; Fink, Lynn; Holmes, Oliver; Chin, Venessa; Anderson, Matthew J; Kazakoff, Stephen; Leonard, Conrad; Newell, Felicity; Waddell, Nick; Wood, Scott; Xu, Qinying; Wilson, Peter J; Cloonan, Nicole; Kassahn, Karin S; Taylor, Darrin; Quek, Kelly; Robertson, Alan; Pantano, Lorena; Mincarelli, Laura; Sanchez, Luis N; Evers, Lisa; Wu, Jianmin; Pinese, Mark; Cowley, Mark J; Jones, Marc D; Colvin, Emily K; Nagrial, Adnan M; Humphrey, Emily S; Chantrill, Lorraine A; Mawson, Amanda; Humphris, Jeremy; Chou, Angela; Pajic, Marina; Scarlett, Christopher J; Pinho, Andreia V; Giry-Laterriere, Marc; Rooman, Ilse; Samra, Jaswinder S; Kench, James G; Lovell, Jessica A; Merrett, Neil D; Toon, Christopher W; Epari, Krishna; Nguyen, Nam Q; Barbour, Andrew; Zeps, Nikolajs; Moran-Jones, Kim; Jamieson, Nigel B; Graham, Janet S; Duthie, Fraser; Oien, Karin; Hair, Jane; Grützmann, Robert; Maitra, Anirban; Iacobuzio-Donahue, Christine A; Wolfgang, Christopher L; Morgan, Richard A; Lawlor, Rita T; Corbo, Vincenzo; Bassi, Claudio; Rusev, Borislav; Capelli, Paola; Salvia, Roberto; Tortora, Giampaolo; Mukhopadhyay, Debabrata; Petersen, Gloria M; Munzy, Donna M; Fisher, William E; Karim, Saadia A; Eshleman, James R; Hruban, Ralph H; Pilarsky, Christian; Morton, Jennifer P; Sansom, Owen J; Scarpa, Aldo; Musgrove, Elizabeth A; Bailey, Ulla-Maja Hagbo; Hofmann, Oliver; Sutherland, Robert L; Wheeler, David A; Gill, Anthony J; Gibbs, Richard A; Pearson, John V; Waddell, Nicola; Biankin, Andrew V; Grimmond, Sean M

    2016-03-03

    Integrated genomic analysis of 456 pancreatic ductal adenocarcinomas identified 32 recurrently mutated genes that aggregate into 10 pathways: KRAS, TGF-β, WNT, NOTCH, ROBO/SLIT signalling, G1/S transition, SWI-SNF, chromatin modification, DNA repair and RNA processing. Expression analysis defined 4 subtypes: (1) squamous; (2) pancreatic progenitor; (3) immunogenic; and (4) aberrantly differentiated endocrine exocrine (ADEX) that correlate with histopathological characteristics. Squamous tumours are enriched for TP53 and KDM6A mutations, upregulation of the TP63∆N transcriptional network, hypermethylation of pancreatic endodermal cell-fate determining genes and have a poor prognosis. Pancreatic progenitor tumours preferentially express genes involved in early pancreatic development (FOXA2/3, PDX1 and MNX1). ADEX tumours displayed upregulation of genes that regulate networks involved in KRAS activation, exocrine (NR5A2 and RBPJL), and endocrine differentiation (NEUROD1 and NKX2-2). Immunogenic tumours contained upregulated immune networks including pathways involved in acquired immune suppression. These data infer differences in the molecular evolution of pancreatic cancer subtypes and identify opportunities for therapeutic development.

  14. Hilar cholangiocarcinoma is pathologically similar to pancreatic duct adenocarcinoma: suggestions of similar background and development.

    Science.gov (United States)

    Nakanuma, Yasuni; Sato, Yasunori

    2014-07-01

    Routine experiences suggest that cholangiocarcinomas (CCAs) show different clinicopathological behaviors along the biliary tree, and hilar CCA apparently resembles pancreatic duct adenocarcinoma (PDAC). Herein, the backgrounds for these similarities were reviewed. While all cases of PDAC, hilar CCA, intrahepatic CCA (ICCA) and CCA components of combined hepatocellular-cholangiocarcinoma (cHC-CCA) were adenocarcinomas, micropapillary patterns and columnar carcinoma cells were common in PDAC and hilar CCA, and trabecular components and cuboidal carcinoma cells were common in ICCA and CCA components of cHC-CCA. Anterior gradient protein-2 and S100P were frequently expressed in perihilar CCA and PDAC, while neural cell adhesion molecule and luminal epithelial membrane antigen were common in CCA components of c-HC-CCA. Pdx1 and Hes1 were frequently and markedly expressed aberrantly in PDAC and perihilar CCA, although their expression was rare and mild in CCA components in cHC-CCA and ICCA. Hilar CCA showed a similar postoperative prognosis to PDAC but differed from ICCA and cHC-CCA. Taken together, hilar CCA may differ from ICCA and CCA components of cHC-CCA but have a similar development to PDAC. These similarities may be explained by the unique anatomical, embryological and reactive nature of the pancreatobiliary tract. Further studies of these intractable malignancies are warranted. © 2014 Japanese Society of Hepato-Biliary-Pancreatic Surgery.

  15. Maturity onset diabetes of youth (MODY) in Turkish children: sequence analysis of 11 causative genes by next generation sequencing.

    Science.gov (United States)

    Ağladıoğlu, Sebahat Yılmaz; Aycan, Zehra; Çetinkaya, Semra; Baş, Veysel Nijat; Önder, Aşan; Peltek Kendirci, Havva Nur; Doğan, Haldun; Ceylaner, Serdar

    2016-04-01

    Maturity-onset diabetes of the youth (MODY), is a genetically and clinically heterogeneous group of diseasesand is often misdiagnosed as type 1 or type 2 diabetes. The aim of this study is to investigate both novel and proven mutations of 11 MODY genes in Turkish children by using targeted next generation sequencing. A panel of 11 MODY genes were screened in 43 children with MODY diagnosed by clinical criterias. Studies of index cases was done with MISEQ-ILLUMINA, and family screenings and confirmation studies of mutations was done by Sanger sequencing. We identified 28 (65%) point mutations among 43 patients. Eighteen patients have GCK mutations, four have HNF1A, one has HNF4A, one has HNF1B, two have NEUROD1, one has PDX1 gene variations and one patient has both HNF1A and HNF4A heterozygote mutations. This is the first study including molecular studies of 11 MODY genes in Turkish children. GCK is the most frequent type of MODY in our study population. Very high frequency of novel mutations (42%) in our study population, supports that in heterogenous disorders like MODY sequence analysis provides rapid, cost effective and accurate genetic diagnosis.

  16. Comprehensive Maturity Onset Diabetes of the Young (MODY) Gene Screening in Pregnant Women with Diabetes in India.

    Science.gov (United States)

    Doddabelavangala Mruthyunjaya, Mahesh; Chapla, Aaron; Hesarghatta Shyamasunder, Asha; Varghese, Deny; Varshney, Manika; Paul, Johan; Inbakumari, Mercy; Christina, Flory; Varghese, Ron Thomas; Kuruvilla, Kurien Anil; V Paul, Thomas; Jose, Ruby; Regi, Annie; Lionel, Jessie; Jeyaseelan, L; Mathew, Jiji; Thomas, Nihal

    2017-01-01

    Pregnant women with diabetes may have underlying beta cell dysfunction due to mutations/rare variants in genes associated with Maturity Onset Diabetes of the Young (MODY). MODY gene screening would reveal those women genetically predisposed and previously unrecognized with a monogenic form of diabetes for further clinical management, family screening and genetic counselling. However, there are minimal data available on MODY gene variants in pregnant women with diabetes from India. In this study, utilizing the Next generation sequencing (NGS) based protocol fifty subjects were screened for variants in a panel of thirteen MODY genes. Of these subjects 18% (9/50) were positive for definite or likely pathogenic or uncertain MODY variants. The majority of these variants was identified in subjects with autosomal dominant family history, of whom five were in women with pre-GDM and four with overt-GDM. The identified variants included one patient with HNF1A Ser3Cys, two PDX1 Glu224Lys, His94Gln, two NEUROD1 Glu59Gln, Phe318Ser, one INS Gly44Arg, one GCK, one ABCC8 Arg620Cys and one BLK Val418Met variants. In addition, three of the seven offspring screened were positive for the identified variant. These identified variants were further confirmed by Sanger sequencing. In conclusion, these findings in pregnant women with diabetes, imply that a proportion of GDM patients with autosomal dominant family history may have MODY. Further NGS based comprehensive studies with larger samples are required to confirm these finding.

  17. Generation of insulin-producing cells from gnotobiotic porcine skin-derived stem cells

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Ji Hoon; Lee, Sung Ho; Heo, Young Tae [Department of Bioscience and Biotechnology, Bio-Organ Research Center, Konkuk University, Seoul 143-701 (Korea, Republic of); Uhm, Sang Jun [Department of Animal Biotechnology, Bio-Organ Research Center, Konkuk University, Seoul 143-701 (Korea, Republic of); Lee, Hoon Taek, E-mail: htl3675@konkuk.ac.kr [Department of Animal Biotechnology, Bio-Organ Research Center, Konkuk University, Seoul 143-701 (Korea, Republic of)

    2010-07-09

    A major problem in the treatment of type 1 diabetes mellitus is the limited availability of alternative sources of insulin-producing cells for islet transplantation. In this study, we investigated the effect of bone morphogenetic protein 4 (BMP-4) treatments of gnotobiotic porcine skin-derived stem cells (gSDSCs) on their reprogramming and subsequent differentiation into insulin-producing cells (IPCs). We isolated SDSCs from the ear skin of a gnotobiotic pig. During the proliferation period, the cells expressed stem-cell markers Oct-4, Sox-2, and CD90; nestin expression also increased significantly. The cells could differentiate into IPCs after treatments with activin-A, glucagon-like peptide-1 (GLP-1), and nicotinamide. After 15 days in the differentiation medium, controlled gSDSCs began expressing endocrine progenitor genes and proteins (Ngn3, Neuro-D, PDX-1, NKX2.2, NKX6.1, and insulin). The IPCs showed increased insulin synthesis after glucose stimulation. The results indicate that stem cells derived from the skin of gnotobiotic pigs can differentiate into IPCs under the appropriate conditions in vitro. Our three-stage induction protocol could be applied without genetic modification to source IPCs from stem cells in the skin of patients with diabetes for autologous transplantation.

  18. Expansion of Adult Human Pancreatic Tissue Yields Organoids Harboring Progenitor Cells with Endocrine Differentiation Potential

    Directory of Open Access Journals (Sweden)

    Cindy J.M. Loomans

    2018-03-01

    Full Text Available Summary: Generating an unlimited source of human insulin-producing cells is a prerequisite to advance β cell replacement therapy for diabetes. Here, we describe a 3D culture system that supports the expansion of adult human pancreatic tissue and the generation of a cell subpopulation with progenitor characteristics. These cells display high aldehyde dehydrogenase activity (ALDHhi, express pancreatic progenitors markers (PDX1, PTF1A, CPA1, and MYC, and can form new organoids in contrast to ALDHlo cells. Interestingly, gene expression profiling revealed that ALDHhi cells are closer to human fetal pancreatic tissue compared with adult pancreatic tissue. Endocrine lineage markers were detected upon in vitro differentiation. Engrafted organoids differentiated toward insulin-positive (INS+ cells, and circulating human C-peptide was detected upon glucose challenge 1 month after transplantation. Engrafted ALDHhi cells formed INS+ cells. We conclude that adult human pancreatic tissue has potential for expansion into 3D structures harboring progenitor cells with endocrine differentiation potential. : In the context of β cell replacement therapy for diabetes, de Koning and colleagues describe a 3D culture platform that supports ex vivo expansion of human pancreatic tissue as organoids. These organoids harbor a subpopulation of ALDHhi cells that display proliferative capacity and can differentiate to an endocrine fate. Keywords: pancreas, organoid, human, ALDH, endocrine differentiation, beta cells, insulin, progenitor, fetal, diabetes

  19. Targeted organ generation using Mixl1-inducible mouse pluripotent stem cells in blastocyst complementation.

    Science.gov (United States)

    Kobayashi, Toshihiro; Kato-Itoh, Megumi; Nakauchi, Hiromitsu

    2015-01-15

    Generation of functional organs from patients' own cells is one of the ultimate goals of regenerative medicine. As a novel approach to creation of organs from pluripotent stem cells (PSCs), we employed blastocyst complementation in organogenesis-disabled animals and successfully generated PSC-derived pancreas and kidneys. Blastocyst complementation, which exploits the capacity of PSCs to participate in forming chimeras, does not, however, exclude contribution of PSCs to the development of tissues-including neural cells or germ cells-other than those specifically targeted by disabling of organogenesis. This fact provokes ethical controversy if human PSCs are to be used. In this study, we demonstrated that forced expression of Mix-like protein 1 (encoded by Mixl1) can be used to guide contribution of mouse embryonic stem cells to endodermal organs after blastocyst injection. We then succeeded in applying this method to generate functional pancreas in pancreatogenesis-disabled Pdx1 knockout mice using a newly developed tetraploid-based organ-complementation method. These findings hold promise for targeted organ generation from patients' own PSCs in livestock animals.

  20. VMAT2 identified as a regulator of late-stage β-cell differentiation.

    Science.gov (United States)

    Sakano, Daisuke; Shiraki, Nobuaki; Kikawa, Kazuhide; Yamazoe, Taiji; Kataoka, Masateru; Umeda, Kahoko; Araki, Kimi; Mao, Di; Matsumoto, Shirou; Nakagata, Naomi; Andersson, Olov; Stainier, Didier; Endo, Fumio; Kume, Kazuhiko; Uesugi, Motonari; Kume, Shoen

    2014-02-01

    Cell replacement therapy for diabetes mellitus requires cost-effective generation of high-quality, insulin-producing, pancreatic β cells from pluripotent stem cells. Development of this technique has been hampered by a lack of knowledge of the molecular mechanisms underlying β-cell differentiation. The present study identified reserpine and tetrabenazine (TBZ), both vesicular monoamine transporter 2 (VMAT2) inhibitors, as promoters of late-stage differentiation of Pdx1-positive pancreatic progenitor cells into Neurog3 (referred to henceforth as Ngn3)-positive endocrine precursors. VMAT2-controlled monoamines, such as dopamine, histamine and serotonin, negatively regulated β-cell differentiation. Reserpine or TBZ acted additively with dibutyryl adenosine 3',5'-cyclic AMP, a cell-permeable cAMP analog, to potentiate differentiation of embryonic stem (ES) cells into β cells that exhibited glucose-stimulated insulin secretion. When ES cell-derived β cells were transplanted into AKITA diabetic mice, the cells reversed hyperglycemia. Our protocol provides a basis for the understanding of β-cell differentiation and its application to a cost-effective production of functional β cells for cell therapy.

  1. Induction of insulin secretion in engineered liver cells by nitric oxide

    Directory of Open Access Journals (Sweden)

    Özcan Sabire

    2007-10-01

    Full Text Available Abstract Background Type 1 Diabetes Mellitus results from an autoimmune destruction of the pancreatic beta cells, which produce insulin. The lack of insulin leads to chronic hyperglycemia and secondary complications, such as cardiovascular disease. The currently approved clinical treatments for diabetes mellitus often fail to achieve sustained and optimal glycemic control. Therefore, there is a great interest in the development of surrogate beta cells as a treatment for type 1 diabetes. Normally, pancreatic beta cells produce and secrete insulin only in response to increased blood glucose levels. However in many cases, insulin secretion from non-beta cells engineered to produce insulin occurs in a glucose-independent manner. In the present study we engineered liver cells to produce and secrete insulin and insulin secretion can be stimulated via the nitric oxide pathway. Results Expression of either human insulin or the beta cell specific transcription factors PDX-1, NeuroD1 and MafA in the Hepa1-6 cell line or primary liver cells via adenoviral gene transfer, results in production and secretion of insulin. Although, the secretion of insulin is not significantly increased in response to high glucose, treatment of these engineered liver cells with L-arginine stimulates insulin secretion up to three-fold. This L-arginine-mediated insulin release is dependent on the production of nitric oxide. Conclusion Liver cells can be engineered to produce insulin and insulin secretion can be induced by treatment with L-arginine via the production of nitric oxide.

  2. De Novo Formation of Insulin-Producing “Neo-β Cell Islets” from Intestinal Crypts

    Directory of Open Access Journals (Sweden)

    Yi-Ju Chen

    2014-03-01

    Full Text Available The ability to interconvert terminally differentiated cells could serve as a powerful tool for cell-based treatment of degenerative diseases, including diabetes mellitus. To determine which, if any, adult tissues are competent to activate an islet β cell program, we performed an in vivo screen by expressing three β cell “reprogramming factors” in a wide spectrum of tissues. We report that transient intestinal expression of these factors—Pdx1, MafA, and Ngn3 (PMN—promotes rapid conversion of intestinal crypt cells into endocrine cells, which coalesce into “neoislets” below the crypt base. Neoislet cells express insulin and show ultrastructural features of β cells. Importantly, intestinal neoislets are glucose-responsive and able to ameliorate hyperglycemia in diabetic mice. Moreover, PMN expression in human intestinal “organoids” stimulates the conversion of intestinal epithelial cells into β-like cells. Our results thus demonstrate that the intestine is an accessible and abundant source of functional insulin-producing cells.

  3. Cyclin-Dependent Kinase 5/p35/p39: A Novel and Imminent Therapeutic Target for Diabetes Mellitus

    Directory of Open Access Journals (Sweden)

    Danish Ahmed

    2011-01-01

    Full Text Available Present therapies to minify hyperglycaemia and insulin resistance mainly target ATP-sensitive K+ channels (KATP of pancreatic cells and PPAR-γ to enhance the insulin secretion and potential for GLUT expression, respectively. These current approaches are frequently associated with the various side effects such as hypoglycaemia and cardiovascular adverse events. CDK5 is a serine/threonine protein kinase, which forms active complexes with p35 or p39 found principally in neurons and in pancreatic β cells. Pieces of evidence from recent studies recommend the vital role of CDK5 in physiological functions in nonneuronal cells such as glucose-stimulated insulin secretion in pancreatic cells. Inhibition of CDK5 averts the decrease of insulin gene expression through the inhibition of nuclear translocation of PDX-1 which is a transcription factor for the insulin gene. The present pieces of evidence designate that CDK5 might be a potential drug target for the regulation of glucose-stimulated insulin secretion in the treatment of diabetes mellitus.

  4. Generation of insulin-producing cells from gnotobiotic porcine skin-derived stem cells

    International Nuclear Information System (INIS)

    Yang, Ji Hoon; Lee, Sung Ho; Heo, Young Tae; Uhm, Sang Jun; Lee, Hoon Taek

    2010-01-01

    A major problem in the treatment of type 1 diabetes mellitus is the limited availability of alternative sources of insulin-producing cells for islet transplantation. In this study, we investigated the effect of bone morphogenetic protein 4 (BMP-4) treatments of gnotobiotic porcine skin-derived stem cells (gSDSCs) on their reprogramming and subsequent differentiation into insulin-producing cells (IPCs). We isolated SDSCs from the ear skin of a gnotobiotic pig. During the proliferation period, the cells expressed stem-cell markers Oct-4, Sox-2, and CD90; nestin expression also increased significantly. The cells could differentiate into IPCs after treatments with activin-A, glucagon-like peptide-1 (GLP-1), and nicotinamide. After 15 days in the differentiation medium, controlled gSDSCs began expressing endocrine progenitor genes and proteins (Ngn3, Neuro-D, PDX-1, NKX2.2, NKX6.1, and insulin). The IPCs showed increased insulin synthesis after glucose stimulation. The results indicate that stem cells derived from the skin of gnotobiotic pigs can differentiate into IPCs under the appropriate conditions in vitro. Our three-stage induction protocol could be applied without genetic modification to source IPCs from stem cells in the skin of patients with diabetes for autologous transplantation.

  5. In Vivo Hypoglycaemic Effect and Inhibitory Mechanism of the Branch Bark Extract of the Mulberry on STZ-Induced Diabetic Mice

    Directory of Open Access Journals (Sweden)

    Hua-Yu Liu

    2014-01-01

    Full Text Available Branch bark extract (BBE derived from the mulberry cultivar Husang 32 (Morus multicaulis L. with aqueous alcohol solution has been investigated as an inhibitor of α-glycosidase in vitro. Mulberry BBE was orally administered to STZ-induced diabetic mice for three weeks, and it improved the weight gain and ameliorated the swelling of liver and kidney in diabetic mice. Obviously, mulberry BBE not only can reduce the abnormally elevated levels of serum insulin and ameliorate insulin resistance induced by STZ, but also it regulates dyslipidemia in diabetic mice. To understand this therapeutic effect and the regulatory mechanisms of BBE in diabetic mice, a qRT-PCR experiment was performed, indicating that the mulberry BBE can regulate the mRNA expression of glycometabolism genes in diabetic mice, including glucose-6-phosphatase (G6Pase, glucokinase (GCK, and phosphoenolpyruvate carboxykinase (PEPCK, thereby regulating sugar metabolism and reducing the blood glucose level in diabetic mice. The mulberry BBE can increase the mRNA expression of the genes Ins1, Ins2 and pancreatic duodenal homeobox-1 (PDX-1 and may decrease the insulin resistance in diabetic mice. Those results provide an important basis for making the best use of mulberry branch resources and producing biomedical drugs with added value.

  6. Essential role of the small GTPase Ran in postnatal pancreatic islet development.

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    Fang Xia

    Full Text Available The small GTPase Ran orchestrates pleiotropic cellular responses of nucleo-cytoplasmic shuttling, mitosis and subcellular trafficking, but whether deregulation of these pathways contributes to disease pathogenesis has remained elusive. Here, we generated transgenic mice expressing wild type (WT Ran, loss-of-function Ran T24N mutant or constitutively active Ran G19V mutant in pancreatic islet β cells under the control of the rat insulin promoter. Embryonic pancreas and islet development, including emergence of insulin(+ β cells, was indistinguishable in control or transgenic mice. However, by one month after birth, transgenic mice expressing any of the three Ran variants exhibited overt diabetes, with hyperglycemia, reduced insulin production, and nearly complete loss of islet number and islet mass, in vivo. Deregulated Ran signaling in transgenic mice, adenoviral over-expression of WT or mutant Ran in isolated islets, or short hairpin RNA (shRNA silencing of endogenous Ran in model insulinoma INS-1 cells, all resulted in decreased expression of the pancreatic and duodenal homeobox transcription factor, PDX-1, and reduced β cell proliferation, in vivo. These data demonstrate that a finely-tuned balance of Ran GTPase signaling is essential for postnatal pancreatic islet development and glucose homeostasis, in vivo.

  7. Expansion and conversion of human pancreatic ductal cells into insulin-secreting endocrine cells.

    Science.gov (United States)

    Lee, Jonghyeob; Sugiyama, Takuya; Liu, Yinghua; Wang, Jing; Gu, Xueying; Lei, Ji; Markmann, James F; Miyazaki, Satsuki; Miyazaki, Jun-Ichi; Szot, Gregory L; Bottino, Rita; Kim, Seung K

    2013-11-19

    Pancreatic islet β-cell insufficiency underlies pathogenesis of diabetes mellitus; thus, functional β-cell replacement from renewable sources is the focus of intensive worldwide effort. However, in vitro production of progeny that secrete insulin in response to physiological cues from primary human cells has proven elusive. Here we describe fractionation, expansion and conversion of primary adult human pancreatic ductal cells into progeny resembling native β-cells. FACS-sorted adult human ductal cells clonally expanded as spheres in culture, while retaining ductal characteristics. Expression of the cardinal islet developmental regulators Neurog3, MafA, Pdx1 and Pax6 converted exocrine duct cells into endocrine progeny with hallmark β-cell properties, including the ability to synthesize, process and store insulin, and secrete it in response to glucose or other depolarizing stimuli. These studies provide evidence that genetic reprogramming of expandable human pancreatic cells with defined factors may serve as a general strategy for islet replacement in diabetes. DOI: http://dx.doi.org/10.7554/eLife.00940.001.

  8. Generation of Functional Beta-Like Cells from Human Exocrine Pancreas.

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    Maria J Lima

    Full Text Available Transcription factor mediated lineage reprogramming of human pancreatic exocrine tissue could conceivably provide an unlimited supply of islets for transplantation in the treatment of diabetes. Exocrine tissue can be efficiently reprogrammed to islet-like cells using a cocktail of transcription factors: Pdx1, Ngn3, MafA and Pax4 in combination with growth factors. We show here that overexpression of exogenous Pax4 in combination with suppression of the endogenous transcription factor ARX considerably enhances the production of functional insulin-secreting β-like cells with concomitant suppression of α-cells. The efficiency was further increased by culture on laminin-coated plates in media containing low glucose concentrations. Immunocytochemistry revealed that reprogrammed cultures were composed of ~45% islet-like clusters comprising >80% monohormonal insulin+ cells. The resultant β-like cells expressed insulin protein levels at ~15-30% of that in adult human islets, efficiently processed proinsulin and packaged insulin into secretory granules, exhibited glucose responsive insulin secretion, and had an immediate and prolonged effect in normalising blood glucose levels upon transplantation into diabetic mice. We estimate that approximately 3 billion of these cells would have an immediate therapeutic effect following engraftment in type 1 diabetes patients and that one pancreas would provide sufficient tissue for numerous transplants.

  9. Clinical relevance of epigenetics in the onset and management of type 2 diabetes mellitus

    Science.gov (United States)

    Sommese, Linda; Zullo, Alberto; Mancini, Francesco Paolo; Fabbricini, Rossella; Soricelli, Andrea; Napoli, Claudio

    2017-01-01

    ABSTRACT Epigenetics is involved in the altered expression of gene networks that underlie insulin resistance and insufficiency. Major genes controlling β-cell differentiation and function, such as PAX4, PDX1, and GLP1 receptor, are epigenetically controlled. Epigenetics can cause insulin resistance through immunomediated pro-inflammatory actions related to several factors, such as NF-kB, osteopontin, and Toll-like receptors. Hereafter, we provide a critical and comprehensive summary on this topic with a particular emphasis on translational and clinical aspects. We discuss the effect of epigenetics on β-cell regeneration for cell replacement therapy, the emerging bioinformatics approaches for analyzing the epigenetic contribution to type 2 diabetes mellitus (T2DM), the epigenetic core of the transgenerational inheritance hypothesis in T2DM, and the epigenetic clinical trials on T2DM. Therefore, prevention or reversion of the epigenetic changes occurring during T2DM development may reduce the individual and societal burden of the disease. PMID:28059593

  10. FGF signaling via MAPK is required early and improves Activin A-induced definitive endoderm formation from human embryonic stem cells

    Energy Technology Data Exchange (ETDEWEB)

    Sui, Lina, E-mail: linasui@vub.ac.be [Cell Differentiation Unit, Diabetes Research Center, Vrije Universiteit Brussel (VUB), Laarbeeklaan 103, 1090 Brussels (Belgium); Mfopou, Josue K. [Cell Differentiation Unit, Diabetes Research Center, Vrije Universiteit Brussel (VUB), Laarbeeklaan 103, 1090 Brussels (Belgium); Geens, Mieke; Sermon, Karen [Department of Embryology and Genetics, Vrije Universiteit Brussel (VUB), Laarbeeklaan 103, 1090 Brussels (Belgium); Bouwens, Luc [Cell Differentiation Unit, Diabetes Research Center, Vrije Universiteit Brussel (VUB), Laarbeeklaan 103, 1090 Brussels (Belgium)

    2012-09-28

    Highlights: Black-Right-Pointing-Pointer Deep study the FGF signaling role during DE specification in the context of hESCs. Black-Right-Pointing-Pointer DE differentiation from hESCs has an early dependence on FGF signaling. Black-Right-Pointing-Pointer A serum-free DE protocol is developed based on the findings. Black-Right-Pointing-Pointer The DE cells showed potential to differentiate into pancreatic progenitor cells. -- Abstract: Considering their unlimited proliferation and pluripotency properties, human embryonic stem cells (hESCs) constitute a promising resource applicable for cell replacement therapy. To facilitate this clinical translation, it is critical to study and understand the early stage of hESCs differentiation wherein germ layers are defined. In this study, we examined the role of FGF signaling in Activin A-induced definitive endoderm (DE) differentiation in the absence of supplemented animal serum. We found that activated FGF/MAPK signaling is required at the early time point of Activin A-induced DE formation. In addition, FGF activation increased the number of DE cells compared to Activin A alone. These DE cells could further differentiate into PDX1 and NKX6.1 positive pancreatic progenitors in vitro. We conclude that Activin A combined with FGF/MAPK signaling efficiently induce DE cells in the absence of serum. These findings improve our understanding of human endoderm formation, and constitute a step forward in the generation of clinical grade hESCs progenies for cell therapy.

  11. FGF signaling via MAPK is required early and improves Activin A-induced definitive endoderm formation from human embryonic stem cells

    International Nuclear Information System (INIS)

    Sui, Lina; Mfopou, Josué K.; Geens, Mieke; Sermon, Karen; Bouwens, Luc

    2012-01-01

    Highlights: ► Deep study the FGF signaling role during DE specification in the context of hESCs. ► DE differentiation from hESCs has an early dependence on FGF signaling. ► A serum-free DE protocol is developed based on the findings. ► The DE cells showed potential to differentiate into pancreatic progenitor cells. -- Abstract: Considering their unlimited proliferation and pluripotency properties, human embryonic stem cells (hESCs) constitute a promising resource applicable for cell replacement therapy. To facilitate this clinical translation, it is critical to study and understand the early stage of hESCs differentiation wherein germ layers are defined. In this study, we examined the role of FGF signaling in Activin A-induced definitive endoderm (DE) differentiation in the absence of supplemented animal serum. We found that activated FGF/MAPK signaling is required at the early time point of Activin A-induced DE formation. In addition, FGF activation increased the number of DE cells compared to Activin A alone. These DE cells could further differentiate into PDX1 and NKX6.1 positive pancreatic progenitors in vitro. We conclude that Activin A combined with FGF/MAPK signaling efficiently induce DE cells in the absence of serum. These findings improve our understanding of human endoderm formation, and constitute a step forward in the generation of clinical grade hESCs progenies for cell therapy.

  12. Sirtuin 1 stimulates the proliferation and the expression of glycolysis genes in pancreatic neoplastic lesions

    Science.gov (United States)

    Pinho, Andreia V.; Mawson, Amanda; Gill, Anthony; Arshi, Mehreen; Warmerdam, Max; Giry-Laterriere, Marc; Eling, Nils; Lie, Triyana; Kuster, Evelyne; Camargo, Simone; Biankin, Andrew V.; Wu, Jianmin; Rooman, Ilse

    2016-01-01

    Metabolic reprogramming is a feature of neoplasia and tumor growth. Sirtuin 1 (SIRT1) is a lysine deacetylase of multiple targets including metabolic regulators such as p53. SIRT1 regulates metaplasia in the pancreas. Nevertheless, it is unclear if SIRT1 affects the development of neoplastic lesions and whether metabolic gene expression is altered. To assess neoplastic lesion development, mice with a pancreas-specific loss of Sirt1 (Pdx1-Cre;Sirt1-lox) were bred into a KrasG12D mutant background (KC) that predisposes to the development of pancreatic intra-epithelial neoplasia (PanIN) and ductal adenocarcinoma (PDAC). Similar grade PanIN lesions developed in KC and KC;Sirt1-lox mice but specifically early mucinous PanINs occupied 40% less area in the KC;Sirt1-lox line, attributed to reduced proliferation. This was accompanied by reduced expression of proteins in the glycolysis pathway, such as GLUT1 and GAPDH. The stimulatory effect of SIRT1 on proliferation and glycolysis gene expression was confirmed in a human PDAC cell line. In resected PDAC samples, higher proliferation and expression of glycolysis genes correlated with poor patient survival. SIRT1 expression per se was not prognostic but low expression of Cell Cycle and Apoptosis Regulator 2 (CCAR2), a reported SIRT1 inhibitor, corresponded to poor patient survival. These findings open perspectives for novel targeted therapies in pancreatic cancer. PMID:27494892

  13. Combined strategy of endothelial cells coating, Sertoli cells coculture and infusion improves vascularization and rejection protection of islet graft.

    Directory of Open Access Journals (Sweden)

    Yang Li

    Full Text Available Improving islet graft revascularization and inhibiting rejection become crucial tasks for prolonging islet graft survival. Endothelial cells (ECs are the basis of islet vascularization and Sertoli cells (SCs have the talent to provide nutritional support and exert immunosuppressive effects. We construct a combined strategy of ECs coating in the presence of nutritious and immune factors supplied by SCs in a co-culture system to investigate the effect of vascularization and rejection inhibition for islet graft. In vivo, the combined strategy improved the survival and vascularization as well as inhibited lymphocytes and inflammatory cytokines. In vitro, we found the combinatorial strategy improved the function of islets and the effect of ECs-coating on islets. Combined strategy treated islets revealed higher levels of anti-apoptotic signal molecules (Bcl-2 and HSP-32, survival and function related molecules (PDX-1, Ki-67, ERK1/2 and Akt and demonstrated increased vascular endothelial growth factor receptor 2 (KDR and angiogenesis signal molecules (FAk and PLC-γ. SCs effectively inhibited the activation of lymphocyte stimulated by islets and ECs. Predominantly immunosuppressive cytokines could be detected in culture supernatants of the SCs coculture group. These results suggest that ECs-coating and Sertoli cells co-culture or infusion synergistically enhance islet survival and function after transplantation.

  14. DNA methylation of candidate genes in peripheral blood from patients with type 2 diabetes or the metabolic syndrome.

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    Sanne D van Otterdijk

    Full Text Available The prevalence of type 2 diabetes (T2D and the metabolic syndrome (MetS is increasing and several studies suggested an involvement of DNA methylation in the development of these metabolic diseases. This study was designed to investigate if differential DNA methylation in blood can function as a biomarker for T2D and/or MetS.Pyrosequencing analyses were performed for the candidate genes KCNJ11, PPARγ, PDK4, KCNQ1, SCD1, PDX1, FTO and PEG3 in peripheral blood leukocytes (PBLs from 25 patients diagnosed with only T2D, 9 patients diagnosed with T2D and MetS and 11 control subjects without any metabolic disorders.No significant differences in gene-specific methylation between patients and controls were observed, although a trend towards significance was observed for PEG3. Differential methylation was observed between the groups in 4 out of the 42 single CpG loci located in the promoters regions of the genes FTO, KCNJ11, PPARγ and PDK4. A trend towards a positive correlation was observed for PEG3 methylation with HDL cholesterol levels.Altered levels of DNA methylation in PBLs of specific loci might serve as a biomarker for T2D or MetS, although further investigation is required.

  15. Long-Term Culture of Self-renewing Pancreatic Progenitors Derived from Human Pluripotent Stem Cells

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    Jamie Trott

    2017-06-01

    Full Text Available Pluripotent stem cells have been proposed as an unlimited source of pancreatic β cells for studying and treating diabetes. However, the long, multi-step differentiation protocols used to generate functional β cells inevitably exhibit considerable variability, particularly when applied to pluripotent cells from diverse genetic backgrounds. We have developed culture conditions that support long-term self-renewal of human multipotent pancreatic progenitors, which are developmentally more proximal to the specialized cells of the adult pancreas. These cultured pancreatic progenitor (cPP cells express key pancreatic transcription factors, including PDX1 and SOX9, and exhibit transcriptomes closely related to their in vivo counterparts. Upon exposure to differentiation cues, cPP cells give rise to pancreatic endocrine, acinar, and ductal lineages, indicating multilineage potency. Furthermore, cPP cells generate insulin+ β-like cells in vitro and in vivo, suggesting that they offer a convenient alternative to pluripotent cells as a source of adult cell types for modeling pancreatic development and diabetes.

  16. NADPH oxidase 2-derived reactive oxygen species mediate FFAs-induced dysfunction and apoptosis of β-cells via JNK, p38 MAPK and p53 pathways.

    Directory of Open Access Journals (Sweden)

    Huiping Yuan

    2010-12-01

    Full Text Available Dysfunction of β-cell is one of major characteristics in the pathogenesis of type 2 diabetes. The combination of obesity and type 2 diabetes, characterized as 'diabesity', is associated with elevated plasma free fatty acids (FFAs. Oxidative stress has been implicated in the pathogenesis of FFA-induced β-cell dysfunction. However, molecular mechanisms linking between reactive oxygen species (ROS and FFA-induced β-cell dysfunction and apoptosis are less clear. In the present study, we test the hypothesis that NOX2-derived ROS may play a critical role in dysfunction and apoptosis of β-cells induced by FFA. Our results show that palmitate and oleate (0.5 mmol/L, 48 h induced JNK activation and AKT inhibition which resulted in decreased phosphorylation of FOXO1 following nuclear localization and the nucleocytoplasmic translocation of PDX-1, leading to the reducing of insulin and ultimately dysfunction of pancreatic NIT-1 cells. We also found that palmitate and oleate stimulated apoptosis of NIT-1 cells through p38MAPK, p53 and NF-κB pathway. More interestingly, our data suggest that suppression of NOX2 may restore FFA-induced dysfunction and apoptosis of NIT-1 cells. Our findings provide a new insight of the NOX2 as a potential new therapeutic target for preservation of β-cell mass and function.

  17. CHOLECYSTOKININ RECEPTOR ANTAGONIST HALTS PROGRESSION OF PANCREATIC CANCER PRECURSOR LESIONS AND FIBROSIS IN MICE

    Science.gov (United States)

    Smith, Jill P.; Cooper, Timothy K.; McGovern, Christopher O.; Gilius, Evan L.; Zhong, Qing; Liao, Jiangang; Molinolo, Alfredo A.; Gutkind, J. Silvio; Matters, Gail L.

    2014-01-01

    Objectives Exogenous administration of cholecystokinin (CCK) induces hypertrophy and hyperplasia of the pancreas with an increase in DNA content. We hypothesized that endogenous CCK is involved with the malignant progression of pancreatic intraepithelial neoplasia (PanIN) lesions and the fibrosis associated with pancreatic cancer. Methods The presence of CCK receptors in early PanIN lesions was examined by immunohistochemistry in mouse and human pancreas. Pdx1-Cre/LSL-KrasG12D transgenic mice were randomized to receive either untreated drinking water or water supplemented with a CCK-receptor antagonist (proglumide, 0.1mg/ml). Pancreas from mice were removed and examined histologically for number and grade of PanINs after 1, 2 or 4 months of antagonist therapy. Results Both CCK-A and CCK-B receptors were identified in early stage PanINs from mouse and human pancreas. The grade of PanIN lesions was reversed and progression to advanced lesions arrested in mice treated with proglumide compared to controls (p=0.004). Furthermore, pancreatic fibrosis was significantly reduced in antagonist-treated animals compared to vehicle (pitalic>0.001). Conclusions These findings demonstrate that endogenous CCK is in part responsible for the development and progression of pancreatic cancer. Use of CCK-receptor antagonists may have a role in cancer prophylaxis in high risk subjects, and may reduce fibrosis in the microenvironment. PMID:25058882

  18. Pancreas-specific deletion of mouse Gata4 and Gata6 causes pancreatic agenesis

    Science.gov (United States)

    Xuan, Shouhong; Borok, Matthew J.; Decker, Kimberly J.; Battle, Michele A.; Duncan, Stephen A.; Hale, Michael A.; Macdonald, Raymond J.; Sussel, Lori

    2012-01-01

    Pancreatic agenesis is a human disorder caused by defects in pancreas development. To date, only a few genes have been linked to pancreatic agenesis in humans, with mutations in pancreatic and duodenal homeobox 1 (PDX1) and pancreas-specific transcription factor 1a (PTF1A) reported in only 5 families with described cases. Recently, mutations in GATA6 have been identified in a large percentage of human cases, and a GATA4 mutant allele has been implicated in a single case. In the mouse, Gata4 and Gata6 are expressed in several endoderm-derived tissues, including the pancreas. To analyze the functions of GATA4 and/or GATA6 during mouse pancreatic development, we generated pancreas-specific deletions of Gata4 and Gata6. Surprisingly, loss of either Gata4 or Gata6 in the pancreas resulted in only mild pancreatic defects, which resolved postnatally. However, simultaneous deletion of both Gata4 and Gata6 in the pancreas caused severe pancreatic agenesis due to disruption of pancreatic progenitor cell proliferation, defects in branching morphogenesis, and a subsequent failure to induce the differentiation of progenitor cells expressing carboxypeptidase A1 (CPA1) and neurogenin 3 (NEUROG3). These studies address the conserved and nonconserved mechanisms underlying GATA4 and GATA6 function during pancreas development and provide a new mouse model to characterize the underlying developmental defects associated with pancreatic agenesis. PMID:23006325

  19. Iridium containing honeycomb Delafossites by topotactic cation exchange.

    Science.gov (United States)

    Roudebush, John H; Ross, K A; Cava, R J

    2016-06-07

    We report the structure and magnetic properties of two new iridium-based honeycomb Delafossite compounds, Cu3NaIr2O6 and Cu3LiIr2O6, formed by a topotactic cation exchange reaction. The starting materials Na2IrO3 and Li2IrO3, which are based on layers of IrO6 octahedra in a honeycomb lattice separated by layers of alkali ions, are transformed to the title compounds by a topotactic exchange reaction through heating with CuCl below 450 °C; higher temperature reactions cause decomposition. The new compounds display dramatically different magnetic behavior from their parent compounds - Cu3NaIr2O6 has a ferromagnetic like magnetic transition at 10 K, while Cu3LiIr2O6 retains the antiferromagnetic transition temperature of its parent compound but displays significantly stronger dominance of antiferromagnetic coupling between spins. These results reveal that a surprising difference in the magnetic interactions between the magnetic Ir ions has been induced by a change in the non-magnetic interlayer species. A combination of neutron and X-ray powder diffraction is used for the structure refinement of Cu3NaIr2O6 and both compounds are compared to their parent materials.

  20. The phase system Fe-Ir-S at 1100, 1000 and 800 degree C

    DEFF Research Database (Denmark)

    Makovicky, Emil; Karup-Møller, Sven

    1999-01-01

    Phase relations in the dry condensed Fe-Ir-S system were determined at 1100, 1000 and 800 degrees C. Orientational runs were performed at 500 degrees C. Between 1100 and 800 degrees C, the system comprises five sulphides and an uninterrupted field of gamma(Fe, Ir). Fe1-xS dissolves 5.8 at.% Ir...... at 1100 degrees C, 3.4 at.% Ir at 1000 degrees C and 1.0 at.% Ir at 800 degrees C. The solubility of Fe in Ir2S3, IrS2 and IrSsimilar to 3 increases with decreasing temperature, reaching 2.5 at.% in the latter two sulphides at 800 degrees C. Thiospinel 'FeIr2S4' is nonstoichiometric, from Fe22.3Ir19.8S58...

  1. Psychosocial and perceived environmental correlates of physical activity in rural and older african american and white women.

    Science.gov (United States)

    Wilcox, Sara; Bopp, Melissa; Oberrecht, Larissa; Kammermann, Sandra K; McElmurray, Charles T

    2003-11-01

    African American and rural older women are among the least active segments of the population. This study, guided by social cognitive theory, examined the correlates of physical activity (PA) in 102 rural older women (41% African American; 70.6 +/- 9.2 years). In bivariate associations, education, marital status, self-efficacy, greater pros than cons, perceived stress, social support, and perceived neighborhood safety were positively associated with PA; age, depressive symptoms, perceived sidewalks, health care provider discussion of PA, and perceived traffic were negatively associated with PA. In a hierarchical regression analysis, the sociodemographic (R(2) = 23%), psychological (IR(2) = 9%), social (IR(2) = 6%), and perceived physical environmental (IR(2) = 9%) sets of variables were significant (p motivators; falls, injuries, and heart attacks were identified most often as risks. These findings support the importance of multilevel influences on PA in older rural women and are useful for informing PA interventions.

  2. Bis[μ-2-(aminosulfanylpyridine(1−]bis[(η5-pentamethylcyclopentadienyliridium(III] diiodide

    Directory of Open Access Journals (Sweden)

    Yusuke Sekioka

    2009-10-01

    Full Text Available In the title dinuclear iridium(III complex, [Ir2(C10H152(C5H5N2S2]I2, the iridium(III atoms are bridged by 2-(aminosulfanylpyridine(1− [(2-pySNH] ligands in a μ-(2-pySNH-κ2N(py,N(NH:κN(NH mode. The dinuclear complex cation lies on a crystallographic inversion center, resulting in a planar Ir2N2 ring with an Ir—N(py bond length of 2.085 (9 Å and bridging Ir—N(NH bonds of 2.110 (9 and 2.113 (9 Å. The two (2-pyS units have mutually anti configurations with respect to the Ir2N2 ring

  3. Phosphatidylcholine transfer protein interacts with thioesterase superfamily member 2 to attenuate insulin signaling.

    Science.gov (United States)

    Ersoy, Baran A; Tarun, Akansha; D'Aquino, Katharine; Hancer, Nancy J; Ukomadu, Chinweike; White, Morris F; Michel, Thomas; Manning, Brendan D; Cohen, David E

    2013-07-30

    Phosphatidylcholine transfer protein (PC-TP) is a phospholipid-binding protein that is enriched in liver and that interacts with thioesterase superfamily member 2 (THEM2). Mice lacking either protein exhibit improved hepatic glucose homeostasis and are resistant to diet-induced diabetes. Insulin receptor substrate 2 (IRS2) and mammalian target of rapamycin complex 1 (mTORC1) are key effectors of insulin signaling, which is attenuated in diabetes. We found that PC-TP inhibited IRS2, as evidenced by insulin-independent IRS2 activation after knockdown, genetic ablation, or chemical inhibition of PC-TP. In addition, IRS2 was activated after knockdown of THEM2, providing support for a role for the interaction of PC-TP with THEM2 in suppressing insulin signaling. Additionally, we showed that PC-TP bound to tuberous sclerosis complex 2 (TSC2) and stabilized the components of the TSC1-TSC2 complex, which functions to inhibit mTORC1. Preventing phosphatidylcholine from binding to PC-TP disrupted interactions of PC-TP with THEM2 and TSC2, and disruption of the PC-TP-THEM2 complex was associated with increased activation of both IRS2 and mTORC1. In livers of mice with genetic ablation of PC-TP or that had been treated with a PC-TP inhibitor, steady-state amounts of IRS2 were increased, whereas those of TSC2 were decreased. These findings reveal a phospholipid-dependent mechanism that suppresses insulin signaling downstream of its receptor.

  4. Insulin receptor substrates 1 and 2 but not Shc can activate the insulin receptor independent of insulin and induce proliferation in CHO-IR cells

    International Nuclear Information System (INIS)

    Niessen, Markus; Jaschinski, Frank; Item, Flurin; McNamara, Morgan P.; Spinas, Giatgen A.; Trueb, Thomas

    2007-01-01

    Ligand-activated insulin receptor (IR) attracts and phosphorylates various substrates such as insulin receptor substrates 1-4 (IRS) and Shc. To investigate how binding affinity for substrate affects signalling we generated chimeric receptors with the β-chain of the insulin receptor containing NPXY motives with different affinities for receptor substrates. We found that the extent of receptor tyrosine phosphorylation positively correlates with binding affinity towards IRS1/2 but not towards Shc. Moreover, overexpression of IRS1 or IRS2 but not of Shc increased IR tyrosine phosphorylation in a dose-dependent manner, also independent of insulin. Molecular truncations of IRS1 revealed that neither the isolated PH and PTB domains nor the C-terminus with the tyrosine phosphorylation sites alone are sufficient for substrate-dependent receptor activation. Overexpression of IRS1 and IRS2 impaired insulin-induced internalization of the IR in a dose-dependent manner suggesting that IRS proteins prevent endosome-associated receptor dephosphorylation/inactivation. IRS1 and IRS2 could therefore target the activated IR to different cellular compartments. Overexpression of IRS1 and IRS2 inhibited insulin-stimulated activation of the MAP kinases Erk1/2 while it increased/induced activation of Akt/PKB. Finally, overexpression of IRS1 and IRS2 but not of Shc induced DNA synthesis in starved CHO-IR cells independent of exogenous growth factors. Our results demonstrate that variations in cellular IRS1 and IRS2 concentration affect insulin signalling both upstream and downstream and that IRS proteins could play instructive rather than just permissive roles in signal transmission

  5. Cloning and characterisation of Schistosoma japonicum insulin receptors.

    Directory of Open Access Journals (Sweden)

    Hong You

    2010-03-01

    Full Text Available Schistosomes depend for growth and development on host hormonal signals, which may include the insulin signalling pathway. We cloned and assessed the function of two insulin receptors from Schistosoma japonicum in order to shed light on their role in schistosome biology.We isolated, from S. japonicum, insulin receptors 1 (SjIR-1 and 2 (SjIR-2 sharing close sequence identity to their S. mansoni homologues (SmIR-1 and SmIR-2. SjIR-1 is located on the tegument basal membrane and the internal epithelium of adult worms, whereas SjIR-2 is located in the parenchyma of males and the vitelline tissue of females. Phylogenetic analysis showed that SjIR-2 and SmIR-2 are close to Echinococcus multilocularis insulin receptor (EmIR, suggesting that SjIR-2, SmIR-2 and EmIR share similar roles in growth and development in the three taxa. Structure homology modelling recovered the conserved structure between the SjIRs and Homo sapiens IR (HIR implying a common predicted binding mechanism in the ligand domain and the same downstream signal transduction processing in the tyrosine kinase domain as in HIR. Two-hybrid analysis was used to confirm that the ligand domains of SjIR-1 and SjIR-2 contain the insulin binding site. Incubation of adult worms in vitro, both with a specific insulin receptor inhibitor and anti-SjIRs antibodies, resulted in a significant decrease in worm glucose levels, suggesting again the same function for SjIRs in regulating glucose uptake as described for mammalian cells.Adult worms of S. japonicum possess insulin receptors that can specifically bind to insulin, indicating that the parasite can utilize host insulin for development and growth by sharing the same pathway as mammalian cells in regulating glucose uptake. A complete understanding of the role of SjIRs in the biology of S. japonicum may result in their use as new targets for drug and vaccine development against schistosomiasis.

  6. Illinois I/O Register to FASTBUS Interface

    International Nuclear Information System (INIS)

    Downing, R.; Lesny, D.; Whitten, W.

    1983-01-01

    The I/O Register to FASTBUS Interface (IORFI) is connected to a processor via two 16-bit output registers (OR1,OR2) and two 16-bit output resisters (IR1,IR2). One of the output registers (OR1) is used to specify the interface function which is to be performed when the interface is accessed via the Data-in Register (IR2) or the Data-out Register (OR2). The other input register (IR1) is used to read the direct status of the FASTBUS lines independent of OR1. The changes made to the SLAC design at the University of Illinois are described

  7. Glucose transport in brain - effect of inflammation.

    Science.gov (United States)

    Jurcovicova, J

    2014-01-01

    Glucose is transported across the cell membrane by specific saturable transport system, which includes two types of glucose transporters: 1) sodium dependent glucose transporters (SGLTs) which transport glucose against its concentration gradient and 2) sodium independent glucose transporters (GLUTs), which transport glucose by facilitative diffusion in its concentration gradient. In the brain, both types of transporters are present with different function, affinity, capacity, and tissue distribution. GLUT1 occurs in brain in two isoforms. The more glycosylated GLUT1 is produced in brain microvasculature and ensures glucose transport across the blood brain barrier (BBB). The less glycosylated form is localized in astrocytic end-feet and cell bodies and is not present in axons, neuronal synapses or microglia. Glucose transported to astrocytes by GLUT1 is metabolized to lactate serving to neurons as energy source. Proinflammatory cytokine interleukin (IL)-1β upregulates GLUT1 in endothelial cells and astrocytes, whereas it induces neuronal death in neuronal cell culture. GLUT2 is present in hypothalamic neurons and serves as a glucose sensor in regulation of food intake. In neurons of the hippocampus, GLUT2 is supposed to regulate synaptic activity and neurotransmitter release. GLUT3 is the most abundant glucose transporter in the brain having five times higher transport capacity than GLUT1. It is present in neuropil, mostly in axons and dendrites. Its density and distribution correlate well with the local cerebral glucose demands. GLUT5 is predominantly fructose transporter. In brain, GLUT5 is the only hexose transporter in microglia, whose regulation is not yet clear. It is not present in neurons. GLUT4 and GLUT8 are insulin-regulated glucose transporters in neuronal cell bodies in the cortex and cerebellum, but mainly in the hippocampus and amygdala, where they maintain hippocampus-dependent cognitive functions. Insulin translocates GLUT4 from cytosol to plasma

  8. Expression of digestive enzymes and nutrient transporters in Eimeria-challenged broilers.

    Science.gov (United States)

    Su, S; Miska, K B; Fetterer, R H; Jenkins, M C; Wong, E A

    2015-03-01

    Avian coccidiosis is a disease caused by the intestinal protozoa Eimeria. The site of invasion and lesions in the intestine is species-specific, for example E. acervulina affects the duodenum, E. maxima the jejunum, and E. tenella the ceca. Lesions in the intestinal mucosa cause reduced feed efficiency and body weight gain. The growth reduction may be due to changes in expression of digestive enzymes and nutrient transporters in the intestine. The objective of this study was to compare the expression of digestive enzymes, nutrient transporters and an antimicrobial peptide in broilers challenged with either E. acervulina, E. maxima or E. tenella. The genes examined included digestive enzymes (APN and SI), peptide and amino acid transporters (PepT1, ASCT1, b(0,+)AT/rBAT, B(0)AT, CAT1, CAT2, EAAT3, LAT1, y(+)LAT1 and y(+)LAT2), sugar transporters (GLUT1, GLUT2, GLUT5 and SGLT1), zinc transporter (ZnT1) and an antimicrobial peptide (LEAP2). Duodenum, jejunum, ileum and ceca were collected 7 days post challenge. E. acervulina challenge resulted in downregulation of various nutrient transporters or LEAP2 in the duodenum and ceca, but not the jejunum or ileum. E. maxima challenge produced both downregulation and upregulation of nutrient transporters and LEAP2 in all three segments of the small intestine and ceca. E. tenella challenge resulted in the downregulation and upregulation of nutrient transporters and LEAP2 in the jejunum, ileum and ceca, but not the duodenum. At the respective target tissue, E. acervulina, E. maxima and E. tenella infection caused common downregulation of APN, b(0,+)AT, rBAT, EAAT3, SI, GLUT2, GLUT5, ZnT1 and LEAP2. The downregulation of nutrient transporters would result in a decrease in the efficiency of protein and polysaccharide digestion and uptake, which may partially explain the weight loss. The downregulation of nutrient transporters may also be a cellular response to reduced expression of the host defense protein LEAP2, which would

  9. Growth hormone abolishes beneficial effects of calorie restriction in long-lived Ames dwarf mice.

    Science.gov (United States)

    Gesing, Adam; Al-Regaiey, Khalid A; Bartke, Andrzej; Masternak, Michal M

    2014-10-01

    Disruption of the growth hormone (GH) axis promotes longevity and delays aging. In contrast, GH over-expression may lead to accelerated aging and shorter life. Calorie restriction (CR) improves insulin sensitivity and may extend lifespan. Long-lived Ames dwarf (df/df) mice have additional extension of longevity when subjected to 30% CR. The aim of the study was to assess effects of CR or GH replacement therapy separately and as a combined (CR+GH) treatment in GH-deficient df/df and normal mice, on selected metabolic parameters (e.g., insulin, glucose, cholesterol), insulin signaling components (e.g., insulin receptor [IR] β-subunit, phosphorylated form of IR [IR pY1158], protein kinase C ζ/λ [p-PKCζ/λ] and mTOR [p-mTOR]), transcription factor p-CREB, and components of the mitogen-activated protein kinase (MAPK) signaling (p-ERK1/2, p-p38), responsible for cell proliferation, differentiation and survival. CR decreased plasma levels of insulin, glucose, cholesterol and leptin, and increased hepatic IR β-subunit and IR pY1158 levels as well as IR, IRS-1 and GLUT-2 gene expression compared to ad libitum feeding, showing a significant beneficial diet intervention effect. Moreover, hepatic protein levels of p-PKCζ/λ, p-mTOR and p-p38 decreased, and p-CREB increased in CR mice. On the contrary, GH increased levels of glucose, cholesterol and leptin in plasma, and p-mTOR or p-p38 in livers, and decreased plasma adiponectin and hepatic IR β-subunit compared to saline treatment. There were no GH effects on adiponectin in N mice. Moreover, GH replacement therapy did not affect IR, IRS-1 and GLUT-2 gene expression. GH treatment abolishes the beneficial effects of CR; it may suggest an important role of GH-IGF1 axis in mediating the CR action. Suppressed somatotrophic signaling seems to predominate over GH replacement therapy in the context of the examined parameters and signaling pathways. Copyright © 2014 Elsevier Inc. All rights reserved.

  10. Effects of Syzygium aromaticum-derived triterpenes on postprandial blood glucose in streptozotocin-induced diabetic rats following carbohydrate challenge.

    Directory of Open Access Journals (Sweden)

    Andile Khathi

    Full Text Available PURPOSE: Recent reports suggest that the hypoglycaemic effects of the triterpenes involve inhibition of glucose transport in the small intestine. Therefore, the effects of Syzygium spp-derived triterpenes oleanolic acid (OA and maslinic acid (MA were evaluated on carbohydrate hydrolyzing enzymes in STZ-induced diabetic rats and consequences on postprandial hyperglycaemia after carbohydrate loading. METHODS: We determined using Western blot analysis the expressions of α-amylase and α-glucosidase and glucose transporters SGLT1 and GLUT2 in the small intestine intestines isolated from diabetic rats treated with OA/MA for 5 weeks. In vitro assays were used to assess the inhibitory activities of OA and MA against α-amylase, α-glucosidase and sucrase. RESULTS: OA and MA ameliorated postprandial hyperglycemia in carbohydrate loaded diabetic rats as indicated by the significantly small glucose area under the curve (AUC in treated diabetic animals compared with that in untreated diabetic rats. Western blotting showed that OA and MA treatment not only down-regulated the increase of SGLT1 and GLUT2 expressions in the small intestine of STZ-induced diabetic rats, but also inhibited small intestine α-amylase, sucrase and α-glucosidase activity. IC50 values of OA against α-amylase (3.60 ± 0.18 mmol/L, α-glucosidase (12.40 ± 0.11 mmol/L and sucrase (11.50 ± 0.13 mmol/L did not significantly differ from those of OA and acarbose. CONCLUSIONS: The results of suggest that OA and MA may be used as potential supplements for treating postprandial hyperglycemia. NOVELTY OF THE WORK: The present observations indicate that besides improving glucose homeostasis in diabetes, OA and MA suppress postprandial hyperglycaemia mediated in part via inhibition of carbohydrate hydrolysis and reduction of glucose transporters in the gastrointestinal tract. Inhibition of α-glucosidase and α-amylase can significantly decrease the postprandial hyperglycaemia after a mixed

  11. Effect of styrene exposure on plasma parameters, molecular mechanisms and gene expression in rat model islet cells.

    Science.gov (United States)

    Niaz, Kamal; Hassan, Fatima Ismail; Mabqool, Faheem; Khan, Fazlullah; Momtaz, Saeideh; Baeeri, Maryam; Navaei-Nigjeh, Mona; Rahimifard, Mahban; Abdollahi, Mohammad

    2017-09-01

    Styrene is an aromatic hydrocarbon compound present in the environment and have primary exposure through plastic industry. The current study was designed to evaluate styrene-induced toxicity parameters in rat plasma fasting blood glucose (FBG) level, oral glucose tolerance, insulin secretion, oxidative stress, and inflammatory cytokines in cellular and molecular levels. Styrene was dissolved in corn oil and administered at different doses (250, 500, 1000, 1500, 2000mg/kg/day and control) to each rat, for 42days. In treated groups, styrene significantly increased fasting blood glucose, plasma insulin (p<0.001) and glucose tolerance. Glucose tolerance, insulin resistance and hyperglycemia were found to be the main consequences correlating gene expression of islet cells. Styrene caused a significant enhancement of oxidative stress markers (p<0.001) and inflammatory cytokines in a dose and concentration-dependent manner in plasma (p<0.001). Moreover, the activities of caspase-3 and -9 of the islet cells were significantly up-regulated by this compound at 1500 and 2000mg/kg/day styrene administrated groups (p<0.001). The relative fold change of GLUD1 was downregulated (p<0.05) and upregulated at 1500 and 2000mg/kg, respectively (p<0.01). The relative fold changes of GLUT2 were down regulated at 250 and 1000mg/kg and up regulated in 500, 1500 and 2000mg/kg doses of styrene (p<0.01). The expression level of GCK indicated a significant upregulation at 250mg/kg and downregulation of relative fold changes in the remaining doses of styrene, except for no change at 2000mg/kg of styrene for GCK. Targeting genes (GLUD1, GLUT2 and GCK) of the pancreatic islet cells in styrene exposed groups, disrupted gluconeogenesis, glycogenolysis pathways and insulin secretory functions. The present study illustrated that fasting blood glucose, insulin pathway, oxidative balance, inflammatory cytokines, cell viability and responsible genes of glucose metabolism are susceptible to styrene

  12. The ethyl acetate fraction of corn silk exhibits dual antioxidant and anti-glycation activities and protects insulin-secreting cells from glucotoxicity.

    Science.gov (United States)

    Chang, Chia-Chuan; Yuan, Wei; Roan, Hsiao-Yuh; Chang, Jia-Ling; Huang, Hsiu-Chen; Lee, Yu-Ching; Tsay, Huey Jen; Liu, Hui-Kang

    2016-11-03

    In this study, we aimed to develop a Stigmata Maydis (corn silk) fraction with dual bio-activities against oxidative stress and protein glycation to protect β-cells from diabetes-induced failure. Corn silk fractions were prepared by partition and chemically characterised by thin-layer chromatography. Free radical scavenging assay, glycation assay, and cell-based viability test (neutral red) were employed to decide the best fraction. Cell death analysis was executed by annexin V/ Propidium iodide staining. Cell proliferation was measured by WST-1. Finally, β-cell function was evaluated by β-cell marker gene expression (RT-PCR) and acute insulin secretion test. Four corn silk fractions were prepared from an ethanolic crude extract of corn silk. In vitro assays indicate ethyl acetate fraction (YMS-EA) was the most potent fraction. YMS-EA also attenuated the hydrogen peroxide- or methylglyoxal-induced induction of reactive oxygen species, reduction of cell viability, and inhibition of cell proliferation. However, YMS-EA was unable to prevent hydrogen peroxide-induced apoptosis or advanced glycation end-products-induced toxicity. Under hyperglycemic conditions, YMS-EA effectively reduced ROS levels, improved mRNA expression of insulin, glucokinase, and PDX-1, and enhanced glucose-stimulated insulin secretion. The similarity of bioactivities among apigenin, luteolin, and YMS-EA indicated that dual activities of YMS-EA might be derived from those compounds. We concluded that YMS-EA fraction could be developed as a preventive food agent against the glucotoxicity to β-cells in Type 2 diabetes.

  13. Adiponectin protects against development of metabolic disturbances in a PCOS mouse model.

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    Benrick, Anna; Chanclón, Belén; Micallef, Peter; Wu, Yanling; Hadi, Laila; Shelton, John M; Stener-Victorin, Elisabet; Wernstedt Asterholm, Ingrid

    2017-08-22

    Adiponectin, together with adipocyte size, is the strongest factor associated with insulin resistance in women with polycystic ovary syndrome (PCOS). This study investigates the causal relationship between adiponectin levels and metabolic and reproductive functions in PCOS. Prepubertal mice overexpressing adiponectin from adipose tissue (APNtg), adiponectin knockouts (APNko), and their wild-type (WT) littermate mice were continuously exposed to placebo or dihydrotestosterone (DHT) to induce PCOS-like traits. As expected, DHT exposure led to reproductive dysfunction, as judged by continuous anestrus, smaller ovaries with a decreased number of corpus luteum, and an increased number of cystic/atretic follicles. A two-way between-groups analysis showed that there was a significant main effect for DHT exposure, but not for genotype, indicating adiponectin does not influence follicle development. Adiponectin had, however, some protective effects on ovarian function. Similar to in many women with PCOS, DHT exposure led to reduced adiponectin levels, larger adipocyte size, and reduced insulin sensitivity in WTs. APNtg mice remained metabolically healthy despite DHT exposure, while APNko-DHT mice were even more insulin resistant than their DHT-exposed littermate WTs. DHT exposure also reduced the mRNA expression of genes involved in metabolic pathways in gonadal adipose tissue of WT and APNko, but this effect of DHT was not observed in APNtg mice. Moreover, APNtg-DHT mice displayed increased pancreatic mRNA levels of insulin receptors, Pdx1 and Igf1R , suggesting adiponectin stimulates beta cell viability/hyperplasia in the context of PCOS. In conclusion, adiponectin improves metabolic health but has only minor effects on reproductive functions in this PCOS-like mouse model.

  14. Human pancreatic islet-derived extracellular vesicles modulate insulin expression in 3D-differentiating iPSC clusters.

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    Diana Ribeiro

    Full Text Available It has been suggested that extracellular vesicles (EVs can mediate crosstalk between hormones and metabolites within pancreatic tissue. However, the possible effect of pancreatic EVs on stem cell differentiation into pancreatic lineages remains unknown. Herein, human islet-derived EVs (h-Islet-EVs were isolated, characterized and subsequently added to human induced pluripotent stem cell (iPSC clusters during pancreatic differentiation. The h-islet-EVs had a mean size of 117±7 nm and showed positive expression of CD63 and CD81 EV markers as measured by ELISA. The presence of key pancreatic transcription factor mRNA, such as NGN3, MAFA and PDX1, and pancreatic hormone proteins such as C-peptide and glucagon, were confirmed in h-Islet-EVs. iPSC clusters were differentiated in suspension and at the end stages of the differentiation protocol, the mRNA expression of the main pancreatic transcription factors and pancreatic hormones was increased. H-Islet-EVs were supplemented to the iPSC clusters in the later stages of differentiation. It was observed that h-Islet-EVs were able to up-regulate the intracellular levels of C-peptide in iPSC clusters in a concentration-dependent manner. The effect of h-Islet-EVs on the differentiation of iPSC clusters cultured in 3D-collagen hydrogels was also assessed. Although increased mRNA expression for pancreatic markers was observed when culturing the iPSC clusters in 3D-collagen hydrogels, delivery of EVs did not affect the insulin or C-peptide intracellular content. Our results provide new information on the role of h-Islet-EVs in the regulation of insulin expression in differentiating iPSC clusters, and are highly relevant for pancreatic tissue engineering applications.

  15. Polydextrose enrichment of infant formula demonstrates prebiotic characteristics by altering intestinal microbiota, organic acid concentrations, and cytokine expression in suckling piglets.

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    Herfel, Tina M; Jacobi, Sheila K; Lin, Xi; Fellner, Vivek; Walker, D Carey; Jouni, Zeina E; Odle, Jack

    2011-12-01

    Oligosaccharides, the 3rd-most abundant component in human milk, are virtually absent from infant formulas and from the cow milk on which most are based. In breast-fed infants, human milk oligosaccharides (HMO) act as both receptor analogs, interfering with pathogen adhesion, and as prebiotics, stimulating the growth of certain commensal bacteria (e.g. bifidobacteria) and supporting the innate immunity. To further align the functional properties of infant formula with those of human milk, polydextrose (PDX) is proposed as a substitute for HMO. To determine the prebiotic functionality of PDX, 1-d-old pigs were fed a cow milk-based formula supplemented with increasing concentrations of PDX (0, 1.7, 4.3, 8.5, or 17 g/L) for 18 d (n = 13). Additional reference groups included pigs sampled at d 0 and sow-reared pigs sampled at d 18 (n = 12). Ileal Lactobacilli CFU, but not Bifidobacteria, increased linearly with increasing PDX (P = 0.02). The propionic acid concentration in digesta linearly increased with the PDX level (P = 0.045) and lactic acid increased linearly by 5-fold with increasing PDX (P = 0.001). Accordingly, digesta pH decreased linearly (P negative quadratic pattern in response to PDX supplementation, declining at intermediate concentrations and rebounding at higher concentrations of PDX. In summary, PDX enrichment of infant formula resulted in a prebiotic effect by increasing ileal lactobacilli and propionic and lactic acid concentrations and decreasing pH with associated alterations in ileal cytokine expression.

  16. Clinical and molecular characterization of a novel INS mutation identified in patients with MODY phenotype.

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    Piccini, Barbara; Artuso, Rosangela; Lenzi, Lorenzo; Guasti, Monica; Braccesi, Giulia; Barni, Federica; Casalini, Emilio; Giglio, Sabrina; Toni, Sonia

    2016-11-01

    Correct diagnosis of Maturity-Onset Diabetes of the Young (MODY) is based on genetic tests requiring an appropriate subject selection by clinicians. Mutations in the insulin (INS) gene rarely occur in patients with MODY. This study is aimed at determining the genetic background and clinical phenotype in patients with suspected MODY. 34 patients with suspected MODY, negative for mutations in the GCK, HNF1α, HNF4α, HNF1β and PDX1 genes, were screened by next generation sequencing (NGS). A heterozygous INS mutation was identified in 4 members of the same family. First genetic tests performed identified two heterozygous silent nucleotide substitutions in MODY3/HNF1α gene. An ineffective attempt to suspend insulin therapy, administering repaglinide and sulphonylureas, was made. DNA was re-sequenced by NGS investigating a set of 102 genes. Genes implicated in the pathway of pancreatic β-cells, candidate genes for type 2 diabetes mellitus and genes causative of diabetes in mice were selected. A novel heterozygous variant in human preproinsulin INS gene (c.125T > C) was found in the affected family members. The new INS mutation broadens the spectrum of possible INS phenotypes. Screening for INS mutations is warranted not only in neonatal diabetes but also in MODYx patients and in selected patients with type 1 diabetes mellitus negative for autoantibodies. Subjects with complex diseases without a specific phenotype should be studied by NGS because Sanger sequencing is ineffective and time consuming in detecting rare variants. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  17. Exploring the Genomic Roadmap and Molecular Phylogenetics Associated with MODY Cascades Using Computational Biology.

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    Chakraborty, Chiranjib; Bandyopadhyay, Sanghamitra; Doss, C George Priya; Agoramoorthy, Govindasamy

    2015-04-01

    Maturity onset diabetes of the young (MODY) is a metabolic and genetic disorder. It is different from type 1 and type 2 diabetes with low occurrence level (1-2%) among all diabetes. This disorder is a consequence of β-cell dysfunction. Till date, 11 subtypes of MODY have been identified, and all of them can cause gene mutations. However, very little is known about the gene mapping, molecular phylogenetics, and co-expression among MODY genes and networking between cascades. This study has used latest servers and software such as VarioWatch, ClustalW, MUSCLE, G Blocks, Phylogeny.fr, iTOL, WebLogo, STRING, and KEGG PATHWAY to perform comprehensive analyses of gene mapping, multiple sequences alignment, molecular phylogenetics, protein-protein network design, co-expression analysis of MODY genes, and pathway development. The MODY genes are located in chromosomes-2, 7, 8, 9, 11, 12, 13, 17, and 20. Highly aligned block shows Pro, Gly, Leu, Arg, and Pro residues are highly aligned in the positions of 296, 386, 437, 455, 456 and 598, respectively. Alignment scores inform us that HNF1A and HNF1B proteins have shown high sequence similarity among MODY proteins. Protein-protein network design shows that HNF1A, HNF1B, HNF4A, NEUROD1, PDX1, PAX4, INS, and GCK are strongly connected, and the co-expression analyses between MODY genes also show distinct association between HNF1A and HNF4A genes. This study has used latest tools of bioinformatics to develop a rapid method to assess the evolutionary relationship, the network development, and the associations among eleven MODY genes and cascades. The prediction of sequence conservation, molecular phylogenetics, protein-protein network and the association between the MODY cascades enhances opportunities to get more insights into the less-known MODY disease.

  18. Identification and Clinical Characterization of Adult Patients with Multigenerational Diabetes Mellitus.

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    Ornella Ludovico

    Full Text Available Some patients diagnosed as having type 2 diabetes mellitus (T2DM are, instead, affected by multigenerational diabetes whose clinical characteristics are mostly undefined.1. To identify among patients who had been previously defined as affected by T2DM those, in fact, affected by multigenerational diabetes; 2. After excluding patients carrying the most common MODY genes and mitochondrial mutations, we compared clinical features of remaining patients with those of patients with T2DM.Among 2,583 consecutive adult patients who had been defined as affected by T2DM, we looked for those with diabetes in ≥3 consecutive generations. All probands were screened for mutations in six MODY genes (HNF4A, GCK, HNF1A, PDX1, HNF1B and NeuroD1 and for the A3243G mitochondrial mutation. After excluding patients with mutations in one of such genes, we compared clinical features of the remaining 67 patients (2.6% of the whole initial sample affected by multigenerational "familial diabetes of the adulthood" (FDA and of their diabetic relatives (n = 63 to those with T2DM (n = 1,028 by generalized hierarchical linear models followed by pairwise comparisons.Age, age at diagnosis, proportion of hypertension (all p<0.001, and waist circumference (p<0.05 were lower in FDA than T2DM. Nonetheless, the two groups had similar age-adjusted incidence rate of all-cause mortality.Beside younger age at diagnosis, FDA patients show lower waist circumference and reduced proportion of hypertension as compared to those with T2DM; despite such reduced potential cardiovascular risk factors, FDA patients did not show a reduced mortality risk than patients with T2DM.

  19. Comprehensive Maturity Onset Diabetes of the Young (MODY Gene Screening in Pregnant Women with Diabetes in India.

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    Mahesh Doddabelavangala Mruthyunjaya

    Full Text Available Pregnant women with diabetes may have underlying beta cell dysfunction due to mutations/rare variants in genes associated with Maturity Onset Diabetes of the Young (MODY. MODY gene screening would reveal those women genetically predisposed and previously unrecognized with a monogenic form of diabetes for further clinical management, family screening and genetic counselling. However, there are minimal data available on MODY gene variants in pregnant women with diabetes from India. In this study, utilizing the Next generation sequencing (NGS based protocol fifty subjects were screened for variants in a panel of thirteen MODY genes. Of these subjects 18% (9/50 were positive for definite or likely pathogenic or uncertain MODY variants. The majority of these variants was identified in subjects with autosomal dominant family history, of whom five were in women with pre-GDM and four with overt-GDM. The identified variants included one patient with HNF1A Ser3Cys, two PDX1 Glu224Lys, His94Gln, two NEUROD1 Glu59Gln, Phe318Ser, one INS Gly44Arg, one GCK, one ABCC8 Arg620Cys and one BLK Val418Met variants. In addition, three of the seven offspring screened were positive for the identified variant. These identified variants were further confirmed by Sanger sequencing. In conclusion, these findings in pregnant women with diabetes, imply that a proportion of GDM patients with autosomal dominant family history may have MODY. Further NGS based comprehensive studies with larger samples are required to confirm these finding.

  20. Comprehensive Maturity Onset Diabetes of the Young (MODY) Gene Screening in Pregnant Women with Diabetes in India

    Science.gov (United States)

    Hesarghatta Shyamasunder, Asha; Varghese, Deny; Varshney, Manika; Paul, Johan; Inbakumari, Mercy; Christina, Flory; Varghese, Ron Thomas; Kuruvilla, Kurien Anil; V. Paul, Thomas; Jose, Ruby; Regi, Annie; Lionel, Jessie; Jeyaseelan, L.; Mathew, Jiji; Thomas, Nihal

    2017-01-01

    Pregnant women with diabetes may have underlying beta cell dysfunction due to mutations/rare variants in genes associated with Maturity Onset Diabetes of the Young (MODY). MODY gene screening would reveal those women genetically predisposed and previously unrecognized with a monogenic form of diabetes for further clinical management, family screening and genetic counselling. However, there are minimal data available on MODY gene variants in pregnant women with diabetes from India. In this study, utilizing the Next generation sequencing (NGS) based protocol fifty subjects were screened for variants in a panel of thirteen MODY genes. Of these subjects 18% (9/50) were positive for definite or likely pathogenic or uncertain MODY variants. The majority of these variants was identified in subjects with autosomal dominant family history, of whom five were in women with pre-GDM and four with overt-GDM. The identified variants included one patient with HNF1A Ser3Cys, two PDX1 Glu224Lys, His94Gln, two NEUROD1 Glu59Gln, Phe318Ser, one INS Gly44Arg, one GCK, one ABCC8 Arg620Cys and one BLK Val418Met variants. In addition, three of the seven offspring screened were positive for the identified variant. These identified variants were further confirmed by Sanger sequencing. In conclusion, these findings in pregnant women with diabetes, imply that a proportion of GDM patients with autosomal dominant family history may have MODY. Further NGS based comprehensive studies with larger samples are required to confirm these finding PMID:28095440

  1. Epithelial Regeneration After Gastric Ulceration Causes Prolonged Cell-Type AlterationsSummary

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    Eitaro Aihara

    2016-09-01

    Full Text Available Background & Aims: The peptic ulcer heals through a complex process, although the ulcer relapse often occurs several years later after healing. Our hypothesis is that even after visual evidence of healing of gastric ulceration, the regenerated epithelium is aberrant for an extended interval, increasing susceptibility of the regenerated epithelium to damage and further diseases. Methods: Gastric ulcers were induced in mice by serosal topical application of acetic acid. Results: Gastric ulcers induced by acetic acid visually healed within 30 days. However, regenerated epithelial architecture was poor. The gene profile of regenerated tissue was abnormal, indicating increased stem/progenitor cells, deficient differentiated gastric cell types, and deranged cell homeostasis. Despite up-regulation of PDX1 in the regenerated epithelium, no mature antral cell type was observed. Four months after healing, the regenerated epithelium lacks parietal cells, trefoil factor 2 (TFF2 and (sex-determining region Y-box 9 (SOX9 remain up-regulated deep in the gastric gland, and the Na/H exchanger 2 (a TFF2 effector in gastric healing remains down-regulated. Gastric ulcer healing was strongly delayed in TFF2 knockout mice, and re-epithelialization was accompanied with mucous metaplasia. After Helicobacter pylori inoculum 30 days after ulceration, we observed that the gastric ulcer selectively relapses at the same site where it originally was induced. Follow-up evaluation at 8 months showed that the relapsed ulcer was not healed in H pylori–infected tissues. Conclusions: These findings show that this macroscopically regenerated epithelium has prolonged abnormal cell distribution and is differentially susceptible to subsequent damage by H pylori. Keywords: Gastric Ulcer Healing, Metaplasia, H pylori, SOX9, TFF2, NHE2

  2. Role of adipose tissue derived stem cells differentiated into insulin producing cells in the treatment of type I diabetes mellitus.

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    Amer, Mona G; Embaby, Azza S; Karam, Rehab A; Amer, Marwa G

    2018-05-15

    Generation of new β cells is an important approach in the treatment of type 1 diabetes mellitus (type 1 DM). Adipose tissue-derived stem cells (ADSCs) might be one of the best sources for cell replacement therapy for diabetes. Therefore, this work aimed to test the possible role of transplanted insulin-producing cells (IPCs) differentiated from ADSCs in treatment of streptozotocin (STZ) induced type I DM in rats. Type 1 DM was induced by single intra peritoneal injection with STZ (50 mg/kg BW). Half of the diabetic rats were left without treatment and the other half were injected with differentiated IPCs directly into the pancreas. ADSCs were harvested, cultured and identified by testing their phenotypes through flow cytometry. They were further subjected to differentiation into IPCs using differentiation medium. mRNA expression of pancreatic transcription factors (pdx1), insulin and glucose transporter-2 genes by real time PCR was done to detect the cellular differentiation and confirmed by stimulated insulin secretion. The pancreatic tissues from all groups were examined 2 months after IPC transplantation and were subjected to histological, Immunohistochemical and morphometric study. The differentiated IPCs showed significant expression of pancreatic β cell markers and insulin secretion in glucose dependent manner. Treatment with IPCs induced apparent regeneration, diffused proliferated islet cells and significant increase in C-peptide immune reaction. We concluded that transplantation of differentiated IPCs improved function and morphology of Islet cells in diabetic rats. Consequently, this therapy option may be a promising therapeutic approach to patient with type 1 DM if proven to be effective and safe. Copyright © 2018 Elsevier B.V. All rights reserved.

  3. Effects of combination therapy with vildagliptin and valsartan in a mouse model of type 2 diabetes

    Science.gov (United States)

    2013-01-01

    Background Dipeptidyl peptidase-4 (DPP-4) inhibitors modulate incretin hormones and exert anti-diabetic effects in type 2 diabetes mellitus. Treatment with angiotensin II type 1 receptor blockers (ARB) is a proven successful intervention for hypertension with type 2 diabetes. The present study investigated the combined effects of the DPP-4 inhibitor vildagliptin and the ARB valsartan in a mouse model of type 2 diabetes. Methods C57BL/6 J mice fed with high-fat diet (HFD) or db/db mice were treated with placebo, phloridzin (PHZ), vildagliptin alone (ViL), valsartan alone (VaL) or ViL with VaL (ViLVaL) for 8 weeks. Results Glucose metabolism was improved in response to PHZ, ViL and ViLVaL in both HFD and db/db mice. Upon glucose challenge, ViLVaL showed the greatest suppression of blood glucose excursions, with increased insulin secretion, in db/db mice. ViLVaL treatment also showed an improvement of insulin sensitivity in db/db mice. Serum inflammatory cytokines were significantly decreased, and adiponectin was highest, in the ViLVaL group. ViLVaL improved insulin signaling and attenuated stress signaling in liver with amelioration of hepatic steatosis due to activated fatty acid oxidation in db/db mice. Furthermore, immunohistochemical analysis of the pancreas revealed that the combination treatment resulted in an increased expression of insulin and PDX-1, and increased insulin content. Conclusions The combination therapy of ViL and VaL improves both pancreatic beta-cell function and insulin sensitivity, with a reduction of the inflammatory and cell stress milieu in mouse models of T2DM. Our results suggest that this combination therapy exerts additive or even synergistic benefits to treat T2DM. PMID:24188631

  4. Knowledge Gaps in Rodent Pancreas Biology: Taking Human Pluripotent Stem Cell-Derived Pancreatic Beta Cells into Our Own Hands.

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    Santosa, Munirah Mohamad; Low, Blaise Su Jun; Pek, Nicole Min Qian; Teo, Adrian Kee Keong

    2015-01-01

    In the field of stem cell biology and diabetes, we and others seek to derive mature and functional human pancreatic β cells for disease modeling and cell replacement therapy. Traditionally, knowledge gathered from rodents is extended to human pancreas developmental biology research involving human pluripotent stem cells (hPSCs). While much has been learnt from rodent pancreas biology in the early steps toward Pdx1(+) pancreatic progenitors, much less is known about the transition toward Ngn3(+) pancreatic endocrine progenitors. Essentially, the later steps of pancreatic β cell development and maturation remain elusive to date. As a result, the most recent advances in the stem cell and diabetes field have relied upon combinatorial testing of numerous growth factors and chemical compounds in an arbitrary trial-and-error fashion to derive mature and functional human pancreatic β cells from hPSCs. Although this hit-or-miss approach appears to have made some headway in maturing human pancreatic β cells in vitro, its underlying biology is vaguely understood. Therefore, in this mini-review, we discuss some of these late-stage signaling pathways that are involved in human pancreatic β cell differentiation and highlight our current understanding of their relevance in rodent pancreas biology. Our efforts here unravel several novel signaling pathways that can be further studied to shed light on unexplored aspects of rodent pancreas biology. New investigations into these signaling pathways are expected to advance our knowledge in human pancreas developmental biology and to aid in the translation of stem cell biology in the context of diabetes treatments.

  5. CISH has no non-redundant functions in glucose homeostasis or beta cell proliferation during pregnancy in mice.

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    Jiao, Yang; Rieck, Sebastian; Le Lay, John; Kaestner, Klaus H

    2013-11-01

    Increased beta cell proliferation during pregnancy is mediated by the Janus kinase 2/signal transducer and activator of transcription 5 (JAK2/STAT5) signalling pathway in response to increased lactogen levels. Activation of the pathway leads to transcriptional upregulation of Cish (encoding cytokine-inducible SH2 domain-containing protein), a member of the suppressor of cytokine signalling (SOCS) family of genes, forming a negative-feedback loop. Here, we examined whether conditional gene ablation of Cish in the pancreas improves beta cell proliferation and beta cell function during pregnancy in mice. We derived mice with a novel, conditional loxP allele for Cish. Pancreas-specific ablation of Cish was achieved by crossing Cish (loxP/loxP) mice with Pdx1-Cre (Early) mice. Beta cell proliferation was quantified by BrdU labelling. Glucose homeostasis was examined with glucose tolerance tests and determination of plasma insulin levels. The expression of other Socs genes and target genes of p-STAT5 related to beta cell function and beta cell proliferation was determined by quantitative PCR. There was no difference in beta cell proliferation or glucose homeostasis between the Cish mutant group and the control group. The p-STAT5 protein level was the same in Cish mutant and control mice. Socs2 gene expression was higher in Cish mutant than control mice at pregnancy day 9.5. The expression of other Socs genes was the same between control and mutant mice. Our results show that CISH has no non-redundant functions in beta cell proliferation or glucose homeostasis during pregnancy in mice. Socs2 might compensate for the loss of Cish during pregnancy.

  6. Insulin-Producing Cells Differentiated from Human Bone Marrow Mesenchymal Stem Cells In Vitro Ameliorate Streptozotocin-Induced Diabetic Hyperglycemia.

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    Ying Xin

    Full Text Available The two major obstacles in the successful transplantation of islets for diabetes treatment are inadequate supply of insulin-producing tissue and immune rejection. Induction of the differentiation of human bone marrow-derived mesenchymal stem cells (hMSCs into insulin-producing cells (IPCs for autologous transplantation may alleviate those limitations.hMSCs were isolated and induced to differentiate into IPCs through a three-stage differentiation protocol in a defined media with high glucose, nicotinamide, and exendin-4. The physiological characteristics and functions of IPCs were then evaluated. Next, about 3 × 10(6 differentiated cells were transplanted into the renal sub-capsular space of streptozotocin (STZ-induced diabetic nude mice. Graft survival and function were assessed by immunohistochemistry, TUNEL staining and measurements of blood glucose levels in the mice.The differentiated IPCs were characterized by Dithizone (DTZ positive staining, expression of pancreatic β-cell markers, and human insulin secretion in response to glucose stimulation. Moreover, 43% of the IPCs showed L-type Ca2+ channel activity and similar changes in intracellular Ca2+ in response to glucose stimulation as that seen in pancreatic β-cells in the process of glucose-stimulated insulin secretion. Transplantation of functional IPCs into the renal subcapsular space of STZ-induced diabetic nude mice ameliorated the hyperglycemia. Immunofluorescence staining revealed that transplanted IPCs sustainably expressed insulin, c-peptide, and PDX-1 without apparent apoptosis in vivo.IPCs derived from hMSCs in vitro can ameliorate STZ-induced diabetic hyperglycemia, which indicates that these hMSCs may be a promising approach to overcome the limitations of islet transplantation.

  7. First Identification of the Toxicity of Microcystins on Pancreatic Islet Function in Humans and the Involved Potential Biomarkers.

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    Zhao, Yanyan; Xue, Qingju; Su, Xiaomei; Xie, Liqiang; Yan, Yunjun; Wang, Lixiao; Steinman, Alan D

    2016-03-15

    Microcystins (MCs) produced by cyanobacteria have been recognized as a major public health threat. However, the toxicity of MCs to humans is still largely unknown. In this study, we examined the changes in pancreatic islet function in fishers exposed to ambient levels of MCs at Lake Taihu and, using a mouse model, explored the molecular mechanisms involved in toxicity. MCs content in the serum of fishers tested positive, with a range from 0.10 to 0.64 μg/L. Both lower blood insulin levels (2.26 ± 0.96 μIU/mL) and impaired fasting glucose were found in participants from the Meiliang Bay area in Lake Taihu, where MC-LR levels were substantially greater than the MC threshold established by WHO for drinking water. Animal experiments showed that glucose level increased by 27.9% in mice exposed to 5 μg/kg bw and decreased by 41.5% in mice exposed to 20 μg/kg bw. Blood insulin levels declined by 21.9% and 56.2% in mice exposed to 5 and 20 μg/kg bw MC-LR, respectively, which was consistent with the results observed in fishers. Furthermore, the diabetes gene pdx1 and several other proteins (such as Ppp3ca, Ide, Marcks, Pgk1, Suclg1, Ndufs4) involved in insulin secretion were identified for the first time in mice following MC-LR exposure; these biomarkers were considered responsible for MC-LR induced islet dysfunction. This study suggests that subchronic exposure to environmental levels of MCs may increase the risk of the occurrence of diabetes in humans.

  8. The Research of Acellular pancreatic bioscaffoldas a natural 3D platform In Vitro

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    Wang, Xin; Li, Zhao

    2018-03-01

    AIM: To investigate the biochemical and functional properties of a rat acellular pancreatic bioscaffold (APB). METHODS: Fresh pancreata were soaked and perfused. The histological structure, the extracellular matrix (ECM) composition, and the DNA content of the APBs were evaluated. After biocompatibility studies, the proliferation, apoptosis and differentiation of AR42J pancreatic acinar cells cultured on APBs were assessed. RESULTS: The pancreatic tissues became translucent after decellularization. The native macroscopic 3D architecture and the ECM ultrastructure were preserved, with large ductal structures and vascular tissue branching from the greater pancreatic artery, but there were no visible vascular endothelial cells, cellular components or cracked cellular debris. The ECM components, including collagen I, collagen IV, fibronectin, laminin and sGAG, were not decreased after decellularization of the APB (P>0.05) however, the DNA content was decreased significantly (P<0.05). The subcutaneous implantation sites showed low immunological response and low cytotoxicity around the APB. The proliferation rate was higher and the apoptosis rate was lower when AR42J cells were cultured on APB than when they were cultured in media alone, on artificial scaffold or ECM (P<0.05). The gene expression of pancreatic duodenal homeodomain containing transcription factor (PDX-1) and pancreatic exocrine transcription factor (PTF-1) and the protein expression of α-Amy, cytokeratin 7 (CK7) and fetal liver kinase-1 (Flk-1) were higher for the APB group than for the other groups (P<0.001). CONCLUSION: Our findings support the biological utility of whole pancreas APBs as biomaterial scaffolds, which provides an improved approach for regenerative medicine.

  9. Oral administration of soybean peptide Vglycin normalizes fasting glucose and restores impaired pancreatic function in Type 2 diabetic Wistar rats.

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    Jiang, Hua; Feng, Jueping; Du, Zhongxia; Zhen, Hui; Lin, Mei; Jia, Shaohui; Li, Tao; Huang, Xinyuan; Ostenson, Claes-Goran; Chen, Zhengwang

    2014-09-01

    Vglycin, a natural 37-residue polypeptide isolated from pea seeds in which six half-cysteine residues are embedded in three pairs of disulfide bonds, is resistant to digestive enzymes and has antidiabetic potential. To investigate the pharmacological activity of Vglycin in vivo and to examine the mechanisms involved, the therapeutic effect of Vglycin in diabetic rats was examined. Diabetes was induced in Wistar rats by high-fat diet and multiple streptozotocin intraperitoneal injections. Diabetic rats were treated daily with Vglycin for 4 weeks. Body weight, food intake, fasting plasma glucose and insulin levels were assayed weekly. Glucose and insulin tolerance tests were conducted on Day 29. Subsequently, levels of p-Akt in the liver and pancreas and cleaved PARP, Pdx-1 and insulin in the pancreas were detected by immunoblotting. The morphology of the pancreas and the insulin expression in the pancreas were analyzed by hematoxylin-eosin staining and immunohistochemistry, respectively. Furthermore, human liver-derived cell lines were used to explore the in vitro effects of Vglycin on insulin sensitivity and glucose uptake. Chronic treatment with Vglycin normalized fasting glucose levels in diabetic rats. The improvement in glucose homeostasis and the increased insulin sensitivity mediated by restored insulin signaling likely contributed to decreased food intake and reduced body weight. Vglycin protected pancreatic cells from damage by streptozotocin. Although insulin synthesis and secretion in impaired β-cell were not significantly elevated, islets morphology was improved in the Vglycin-treated groups. These results suggest that Vglycin could be useful in Type 2 diabetes for restoring impaired insulin signaling, glucose tolerance and pancreatic function. Copyright © 2014 Elsevier Inc. All rights reserved.

  10. Extra-pancreatic invasion induces lipolytic and fibrotic changes in the adipose microenvironment, with released fatty acids enhancing the invasiveness of pancreatic cancer cells

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    Okumura, Takashi; Ohuchida, Kenoki; Sada, Masafumi; Abe, Toshiya; Endo, Sho; Koikawa, Kazuhiro; Iwamoto, Chika; Miura, Daisuke; Mizuuchi, Yusuke; Moriyama, Taiki; Nakata, Kohei; Miyasaka, Yoshihiro; Manabe, Tatsuya; Ohtsuka, Takao; Nagai, Eishi; Mizumoto, Kazuhiro; Oda, Yoshinao; Hashizume, Makoto; Nakamura, Masafumi

    2017-01-01

    Pancreatic cancer progression involves components of the tumor microenvironment, including stellate cells, immune cells, endothelial cells, and the extracellular matrix. Although peripancreatic fat is the main stromal component involved in extra-pancreatic invasion, its roles in local invasion and metastasis of pancreatic cancer remain unclear. This study investigated the role of adipose tissue in pancreatic cancer progression using genetically engineered mice (Pdx1-Cre; LSL-KrasG12D; Trp53R172H/+) and an in vitro model of organotypic fat invasion. Mice fed a high fat diet had significantly larger primary pancreatic tumors and a significantly higher rate of distant organ metastasis than mice fed a standard diet. In the organotypic fat invasion model, pancreatic cancer cell clusters were smaller and more elongated in shape and showed increased fibrosis. Adipose tissue-derived conditioned medium enhanced pancreatic cancer cell invasiveness and gemcitabine resistance, as well as inducing morphologic changes in cancer cells and increasing the numbers of lipid droplets in their cytoplasm. The concentrations of oleic, palmitoleic, and linoleic acids were higher in adipose tissue-derived conditioned medium than in normal medium, with these fatty acids significantly enhancing the migration of cancer cells. Mature adipocytes were smaller and the concentration of fatty acids in the medium higher when these cells were co-cultured with cancer cells. These findings indicate that lipolytic and fibrotic changes in peripancreatic adipose tissue enhance local invasiveness and metastasis via adipocyte-released fatty acids. Inhibition of fatty acid uptake by cancer cells may be a novel therapy targeting interactions between cancer and stromal cells. PMID:28407685

  11. Short-term selective alleviation of glucotoxicity and lipotoxicity ameliorates the suppressed expression of key β-cell factors under diabetic conditions

    Energy Technology Data Exchange (ETDEWEB)

    Shimo, Naoki [Department of Metabolic Medicine, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, 565-0871 (Japan); Matsuoka, Taka-aki, E-mail: matsuoka@endmet.med.osaka-u.ac.jp [Department of Metabolic Medicine, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, 565-0871 (Japan); Miyatsuka, Takeshi [Department of Metabolic Medicine, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, 565-0871 (Japan); Department of Metabolism and Endocrinology, Juntendo University Graduate School of Medicine, 2-1-1 Hongo, Bunky-ku, Tokyo, 113-8421 (Japan); Takebe, Satomi; Tochino, Yoshihiro; Takahara, Mitsuyoshi [Department of Metabolic Medicine, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, 565-0871 (Japan); Kaneto, Hideaki [Division of Diabetes, Endocrinology and Metabolism, Kawasaki Medical School, 577 Matsushima, Kurashiki-city, Okayama, 701-0192 (Japan); Shimomura, Iichiro [Department of Metabolic Medicine, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, 565-0871 (Japan)

    2015-11-27

    Alleviation of hyperglycaemia and hyperlipidemia improves pancreatic β-cell function in type 2 diabetes. However, the underlying molecular mechanisms are still not well clarified. In this study, we aimed to elucidate how the expression alterations of key β-cell factors are altered by the short-term selective alleviation of glucotoxicity or lipotoxicity. We treated db/db mice for one week with empagliflozin and/or bezafibrate to alleviate glucotoxicity and/or liptotoxicity, respectively. The gene expression levels of Pdx1 and Mafa, and their potential targets, insulin 1, Slc2a2, and Glp1r, were higher in the islets of empagliflozin-treated mice, and levels of insulin 2 were higher in mice treated with both reagents, than in untreated mice. Moreover, compared to the pretreatment levels, Mafa and insulin 1 expression increased in empagliflozin-treated mice, and Slc2a2 increased in combination-treated mice. In addition, empagliflozin treatment enhanced β-cell proliferation assessed by Ki-67 immunostaining. Our date clearly demonstrated that the one-week selective alleviation of glucotoxicity led to the better expression levels of the key β-cell factors critical for β-cell function over pretreatment levels, and that the alleviation of lipotoxicity along with glucotoxicity augmented the favorable effects under diabetic conditions. - Highlights: • One-week selective reduction of gluco- and lipo-toxicity in db/db mice was performed. • Selective glucotoxicity reduction increases key pancreatic β-cell factors expression. • Selective glucotoxicity reduction improves β-cell factors over pretreatment levels. • Selective glucotoxicity reduction turns β-cell mass toward increase. • Lipotoxicity reduction has additive effects on glucotoxicity reduction.

  12. YKL-40 is differentially expressed in human embryonic stem cells and in cell progeny of the three germ layers.

    Science.gov (United States)

    Brøchner, Christian B; Johansen, Julia S; Larsen, Lars A; Bak, Mads; Mikkelsen, Hanne B; Byskov, Anne Grete; Andersen, Claus Yding; Møllgård, Kjeld

    2012-03-01

    The secreted glycoprotein YKL-40 participates in cell differentiation, inflammation, and cancer progression. High YKL-40 expression is reported during early human development, but its functions are unknown. Six human embryonic stem cell (hESC) lines were cultured in an atmosphere of low or high oxygen tension, in culture medium with or without basic fibroblast growth factor, and on feeder layers comprising mouse embryonic fibroblasts or human foreskin fibroblasts to evaluate whether hESCs and their progeny produced YKL-40 and to characterize YKL-40 expression during differentiation. Secreted YKL-40 protein and YKL-40 mRNA expression were measured by enzyme-linked immunosorbent assay (ELISA) and quantitative RT-PCR. Serial-sectioned colonies were stained for YKL-40 protein and for pluripotent hESC (OCT4, NANOG) and germ layer (HNF-3β, PDX1, CD34, p63, nestin, PAX6) markers. Double-labeling showed YKL-40 expression in OCT4-positive hESCs, PAX6-positive neuroectodermal cells, and HNF-3β-positive endodermal cells. The differentiating progeny showed strong YKL-40 expression. Abrupt transition between YKL-40 and OCT4-positive hESCs and YKL-40-positive ecto- and neuroectodermal lineages was observed within the same epithelial-like layer. YKL-40-positive cells within deeper layers lacked contact with OCT4-positive cells. YKL-40 may be important in initial cell differentiation from hESCs toward ectoderm and neuroectoderm, with retained epithelial morphology, whereas later differentiation into endoderm and mesoderm involves a transition into the deeper layers of the colony.

  13. High-fructose diet is as detrimental as high-fat diet in the induction of insulin resistance and diabetes mediated by hepatic/pancreatic endoplasmic reticulum (ER) stress.

    Science.gov (United States)

    Balakumar, M; Raji, L; Prabhu, D; Sathishkumar, C; Prabu, P; Mohan, V; Balasubramanyam, M

    2016-12-01

    In the context of high human consumption of fructose diets, there is an imperative need to understand how dietary fructose intake influence cellular and molecular mechanisms and thereby affect β-cell dysfunction and insulin resistance. While evidence exists for a relationship between high-fat-induced insulin resistance and metabolic disorders, there is lack of studies in relation to high-fructose diet. Therefore, we attempted to study the effect of different diets viz., high-fat diet (HFD), high-fructose diet (HFS), and a combination (HFS + HFD) diet on glucose homeostasis and insulin sensitivity in male Wistar rats compared to control animals fed with normal pellet diet. Investigations include oral glucose tolerance test, insulin tolerance test, histopathology by H&E and Masson's trichrome staining, mRNA expression by real-time PCR, protein expression by Western blot, and caspase-3 activity by colorimetry. Rats subjected to high-fat/fructose diets became glucose intolerant, insulin-resistant, and dyslipidemic. Compared to control animals, rats subjected to different combination of fat/fructose diets showed increased mRNA and protein expression of a battery of ER stress markers both in pancreas and liver. Transcription factors of β-cell function (INSIG1, SREBP1c and PDX1) as well as hepatic gluconeogenesis (FOXO1 and PEPCK) were adversely affected in diet-induced insulin-resistant rats. The convergence of chronic ER stress towards apoptosis in pancreas/liver was also indicated by increased levels of CHOP mRNA & increased activity of both JNK and Caspase-3 in rats subjected to high-fat/fructose diets. Our study exposes the experimental support in that high-fructose diet is equally detrimental in causing metabolic disorders.

  14. The species origin of the cellular microenvironment influences markers of beta cell fate and function in EndoC-βH1 cells.

    Science.gov (United States)

    Jeffery, N; Richardson, S; Beall, C; Harries, L W

    2017-12-15

    Interaction between islet cell subtypes and the extracellular matrix influences beta-cell function in mammals. The tissue architecture of rodent islets is very different to that of human islets; cell-to-cell communication and interaction with the extracellular matrix may vary between species. In this work, we have compared the responses of the human EndoC-βH1 cell line to non-human and human-derived growth matrices in terms of growth morphology, gene expression and glucose-stimulated insulin secretion (GSIS). EndoC-βH1 cells demonstrated a greater tendency to form cell clusters when cultured in a human microenvironment and exhibited reduced alpha cell markers at the mRNA level; mean expression difference - 0.23 and - 0.51; p = 0.009 and 0.002 for the Aristaless-related homeobox (ARX) and Glucagon (GCG) genes respectively. No differences were noted in the protein expression of mature beta cell markers such as Pdx1 and NeuroD1 were noted in EndoC-βH1 cells grown in a human microenvironment but cells were however more sensitive to glucose (4.3-fold increase in insulin secretion following glucose challenge compared with a 1.9-fold increase in cells grown in a non-human microenvironment; p = 0.0003). Our data suggests that the tissue origin of the cellular microenvironment has effects on the function of EndoC-βH1 cells in vitro, and the use of a more human-like culture microenvironment may bring benefits in terms of increased physiological relevance. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. Heterologous Expression and Delivery of Biologically Active Exendin-4 by Lactobacillus paracasei L14.

    Directory of Open Access Journals (Sweden)

    Zhu Zeng

    Full Text Available Exendin-4, a glucagon-like protein-1 (GLP-1 receptor agonist, is an excellent therapeutic peptide drug for type 2 diabetes due to longer lasting biological activity compared to GLP-1. This study explored the feasibility of using probiotic Lactobacillus paracasei as an oral vector for recombinant exendin-4 peptide delivery, an alternative to costly chemical synthesis and inconvenient administration by injection. L. paracasei transformed with a plasmid encoding the exendin-4 gene (L. paracasei L14/pMG76e-exendin-4 with a constitutive promotor was successfully constructed and showed efficient secretion of exendin-4. The secreted exendin-4 significantly enhanced insulin secretion of INS-1 β-cells, along with an increment in their proliferation and inhibition of their apoptosis, corresponding to the effect of GLP-1 on these cells. The transcription level of the pancreatic duodenal homeobox-1 gene (PDX-1, a key transcription factor for cellular insulin synthesis and secretion, was upregulated by the treatment with secreted exendin-4, paralleling the upregulation of insulin gene expression. Caco-2 cell monolayer permeability assay showed a 34-fold increase in the transport of exendin-4 delivered by L. paracasei vs. that of free exendin-4 (control, suggesting effective facilitation of exendin-4 transport across the intestinal barrier by this delivery system. This study demonstrates that the probiotic Lactobacillus can be engineered to secrete bioactive exendin-4 and facilitate its transport through the intestinal barrier, providing a novel strategy for oral exendin-4 delivery using this lactic acid bacterium.

  16. Islet-like cell aggregates generated from human adipose tissue derived stem cells ameliorate experimental diabetes in mice.

    Directory of Open Access Journals (Sweden)

    Vikash Chandra

    Full Text Available BACKGROUND: Type 1 Diabetes Mellitus is caused by auto immune destruction of insulin producing beta cells in the pancreas. Currently available treatments include transplantation of isolated islets from donor pancreas to the patient. However, this method is limited by inadequate means of immuno-suppression to prevent islet rejection and importantly, limited supply of islets for transplantation. Autologous adult stem cells are now considered for cell replacement therapy in diabetes as it has the potential to generate neo-islets which are genetically part of the treated individual. Adopting methods of islet encapsulation in immuno-isolatory devices would eliminate the need for immuno-suppressants. METHODOLOGY/PRINCIPAL FINDINGS: In the present study we explore the potential of human adipose tissue derived adult stem cells (h-ASCs to differentiate into functional islet like cell aggregates (ICAs. Our stage specific differentiation protocol permit the conversion of mesodermic h-ASCs to definitive endoderm (Hnf3β, TCF2 and Sox17 and to PDX1, Ngn3, NeuroD, Pax4 positive pancreatic endoderm which further matures in vitro to secrete insulin. These ICAs are shown to produce human C-peptide in a glucose dependent manner exhibiting in-vitro functionality. Transplantation of mature ICAs, packed in immuno-isolatory biocompatible capsules to STZ induced diabetic mice restored near normoglycemia within 3-4 weeks. The detection of human C-peptide, 1155±165 pM in blood serum of experimental mice demonstrate the efficacy of our differentiation approach. CONCLUSIONS: h-ASC is an ideal population of personal stem cells for cell replacement therapy, given that they are abundant, easily available and autologous in origin. Our findings present evidence that h-ASCs could be induced to differentiate into physiologically competent functional islet like cell aggregates, which may provide as a source of alternative islets for cell replacement therapy in type 1 diabetes.

  17. Altered MENIN expression disrupts the MAFA differentiation pathway in insulinoma.

    Science.gov (United States)

    Hamze, Z; Vercherat, C; Bernigaud-Lacheretz, A; Bazzi, W; Bonnavion, R; Lu, J; Calender, A; Pouponnot, C; Bertolino, P; Roche, C; Stein, R; Scoazec, J Y; Zhang, C X; Cordier-Bussat, M

    2013-12-01

    The protein MENIN is the product of the multiple endocrine neoplasia type I (MEN1) gene. Altered MENIN expression is one of the few events that are clearly associated with foregut neuroendocrine tumours (NETs), classical oncogenes or tumour suppressors being not involved. One of the current challenges is to understand how alteration of MENIN expression contributes to the development of these tumours. We hypothesised that MENIN might regulate factors maintaining endocrine-differentiated functions. We chose the insulinoma model, a paradigmatic example of well-differentiated pancreatic NETs, to study whether MENIN interferes with the expression of v-MAF musculoaponeurotic fibrosarcoma oncogene homologue A (MAFA), a master glucose-dependent transcription factor in differentiated β-cells. Immunohistochemical analysis of a series of human insulinomas revealed a correlated decrease in both MENIN and MAFA. Decreased MAFA expression resulting from targeted Men1 ablation was also consistently observed in mouse insulinomas. In vitro analyses using insulinoma cell lines showed that MENIN regulated MAFA protein and mRNA levels, and bound to Mafa promoter sequences. MENIN knockdown concomitantly decreased mRNA expression of both Mafa and β-cell differentiation markers (Ins1/2, Gck, Slc2a2 and Pdx1) and, in parallel, increased the proliferation rate of tumours as measured by bromodeoxyuridine incorporation. Interestingly, MAFA knockdown alone also increased proliferation rate but did not affect the expression of candidate proliferation genes regulated by MENIN. Finally, MENIN variants with missense mutations detected in patients with MEN1 lost the WT MENIN properties to regulate MAFA. Together, our findings unveil a previously unsuspected MENIN/MAFA connection regarding control of the β-cell differentiation/proliferation balance, which could contribute to tumorigenesis.

  18. FGF7 and cell density are required for final differentiation of pancreatic amylase-positive cells from human ES cells.

    Science.gov (United States)

    Takizawa-Shirasawa, Sakiko; Yoshie, Susumu; Yue, Fengming; Mogi, Akimi; Yokoyama, Tadayuki; Tomotsune, Daihachiro; Sasaki, Katsunori

    2013-12-01

    The major molecular signals of pancreatic exocrine development are largely unknown. We examine the role of fibroblast growth factor 7 (FGF7) in the final induction of pancreatic amylase-containing exocrine cells from induced-pancreatic progenitor cells derived from human embryonic stem (hES) cells. Our protocol consisted in three steps: Step I, differentiation of definitive endoderm (DE) by activin A treatment of hES cell colonies; Step II, differentiation of pancreatic progenitor cells by re-plating of the cells of Step I onto 24-well plates at high density and stimulation with all-trans retinoic acid; Step III, differentiation of pancreatic exocrine cells with a combination of FGF7, glucagon-like peptide 1 and nicotinamide. The expression levels of pancreatic endodermal markers such as Foxa2, Sox17 and gut tube endoderm marker HNF1β were up-regulated in both Step I and II. Moreover, in Step III, the induced cells expressed pancreatic markers such as amylase, carboxypeptidase A and chymotrypsinogen B, which were similar to those in normal human pancreas. From day 8 in Step III, cells immunohistochemically positive for amylase and for carboxypeptidase A, a pancreatic exocrine cell product, were induced by FGF7. Pancreatic progenitor Pdx1-positive cells were localized in proximity to the amylase-positive cells. In the absence of FGF7, few amylase-positive cells were identified. Thus, our three-step culture protocol for human ES cells effectively induces the differentiation of amylase- and carboxypeptidase-A-containing pancreatic exocrine cells.

  19. In vitro expansion and differentiation of rat pancreatic duct-derived stem cells into insulin secreting cells using a dynamicthree-dimensional cell culture system.

    Science.gov (United States)

    Chen, X C; Liu, H; Li, H; Cheng, Y; Yang, L; Liu, Y F

    2016-06-27

    In this study, a dynamic three-dimensional cell culture technology was used to expand and differentiate rat pancreatic duct-derived stem cells (PDSCs) into islet-like cell clusters that can secrete insulin. PDSCs were isolated from rat pancreatic tissues by in situ collagenase digestion and density gradient centrifugation. Using a dynamic three-dimensional culture technique, the cells were expanded and differentiated into functional islet-like cell clusters, which were characterized by morphological and phenotype analyses. After maintaining 1 x 108 isolated rat PDSCs in a dynamic three-dimensional cell culture for 7 days, 1.5 x 109 cells could be harvested. Passaged PDSCs expressed markers of pancreatic endocrine progenitors, including CD29 (86.17%), CD73 (90.73%), CD90 (84.13%), CD105 (78.28%), and Pdx-1. Following 14 additional days of culture in serum-free medium with nicotinamide, keratinocyte growth factor (KGF), and b fibroblast growth factor (FGF), the cells were differentiated into islet-like cell clusters (ICCs). The ICC morphology reflected that of fused cell clusters. During the late stage of differentiation, representative clusters were non-adherent and expressed insulin indicated by dithizone (DTZ)-positive staining. Insulin was detected in the extracellular fluid and cytoplasm of ICCs after 14 days of differentiation. Additionally, insulin levels were significantly higher at this time compared with the levels exhibited by PDSCs before differentiation (P cell culture system, PDSCs can be expanded in vitro and can differentiate into functional islet-like cell clusters.

  20. Insulin Receptor Substrate 2 Is a Negative Regulator of Memory Formation

    Science.gov (United States)

    Irvine, Elaine E.; Drinkwater, Laura; Radwanska, Kasia; Al-Qassab, Hind; Smith, Mark A.; O'Brien, Melissa; Kielar, Catherine; Choudhury, Agharul I.; Krauss, Stefan; Cooper, Jonathan D.; Withers, Dominic J.; Giese, Karl Peter

    2011-01-01

    Insulin has been shown to impact on learning and memory in both humans and animals, but the downstream signaling mechanisms involved are poorly characterized. Insulin receptor substrate-2 (Irs2) is an adaptor protein that couples activation of insulin- and insulin-like growth factor-1 receptors to downstream signaling pathways. Here, we have…

  1. Theoretical study of the electron paramagnetic resonance ...

    Indian Academy of Sciences (India)

    conveniently investigated by means of electron paramagnetic resonance (EPR). In ... ion Ir2+ can experience the Jahn–Teller effect by means of vibration interaction, ... Similarly, k. (and k ) are the orbital reduction factors arising from the anisotropic interactions of the orbital angular momentum operator. From the cluster ...

  2. A Prospective Cohort Study on IRS Gene Polymorphisms in Type 2 ...

    African Journals Online (AJOL)

    Insulin resistance status was determined using the homeostatic model assessment for insulin resistance (HOMA-IR) index. Results: IRS1 polymorphisms were associated with increased insulin resistance (X2 = 5.09, p = 0.023) in T2DM patients with severe/acute hyperglycemia. IRS2 polymorphisms were not associated with ...

  3. Phospholipase C-dependent hydrolysis of phosphatidylinositol 4,5-bisphosphate underlies agmatine-induced suppression of N-type Ca2+ channel in rat celiac ganglion neurons.

    Science.gov (United States)

    Kim, Young-Hwan; Jeong, Ji-Hyun; Ahn, Duck-Sun; Chung, Seungsoo

    2017-03-04

    Agmatine suppresses peripheral sympathetic tone by modulating Cav2.2 channels in peripheral sympathetic neurons. However, the detailed cellular signaling mechanism underlying the agmatine-induced Cav2.2 inhibition remains unclear. Therefore, in the present study, we investigated the electrophysiological mechanism for the agmatine-induced inhibition of Cav2.2 current (I Cav2.2 ) in rat celiac ganglion (CG) neurons. Consistent with previous reports, agmatine inhibited I Cav2.2 in a VI manner. The agmatine-induced inhibition of the I Cav2.2 current was also almost completely hindered by the blockade of the imidazoline I 2 receptor (IR 2 ), and an IR 2 agonist mimicked the inhibitory effect of agmatine on I Cav2.2 , implying involvement of IR 2 . The agmatine-induced I Cav2.2 inhibition was significantly hampered by the blockade of G protein or phospholipase C (PLC), but not by the pretreatment with pertussis toxin. In addition, diC8-phosphatidylinositol 4,5-bisphosphate (PIP 2 ) dialysis nearly completely hampered agmatine-induced inhibition, which became irreversible when PIP 2 resynthesis was blocked. These results suggest that in rat peripheral sympathetic neurons, agmatine-induced IR 2 activation suppresses Cav2.2 channel voltage-independently, and that the PLC-dependent PIP 2 hydrolysis is responsible for the agmatine-induced suppression of the Cav2.2 channel. Copyright © 2017 Elsevier Inc. All rights reserved.

  4. Anion–Anion Bonding and Topology in Ternary Iridium Seleno–Stannides

    Energy Technology Data Exchange (ETDEWEB)

    Trump, Benjamin A.; Tutmaher, Jake A.; McQueen, Tyrel M. (JHU)

    2015-12-21

    The synthesis and physical properties of two new and one known Ir–Sn–Se compound are reported. Their crystal structures are elucidated with transmission electron microscopy and powder X-ray diffraction. IrSn0.45Se1.55 is a pyrite phase which consists of tilted corner-sharing IrX6 octahedra with randomly distributed (Sn–Se)4– and (Se–Se)2– dimers. Ir2Sn3Se3 is a known trigonally distorted skutterudite that consists of cooperatively tilted corner-sharing IrSn3Se3 octahedra with ordered (Sn–Se)24– tetramers. Ir2SnSe5 is a layered, distorted β-MnO2 (pyrolusite) structure consisting of a double IrSe6 octrahedral row, corner sharing in the a direction and edge sharing in the b direction. This distorted pyrolusite contains (Se–Se)2– dimers and Se2– anions, and each double row is “capped” with a (Sn–Se)n polymeric chain. Resistivity, specific heat, and magnetization measurements show that all three have insulating and diamagnetic behavior, indicative of low-spin 5d6 Ir3+. Electronic structure calculations on Ir2Sn3Se3 show a single, spherical, nonspin–orbit split valence band and suggest that Ir2Sn3Se3 is topologically nontrivial under tensile strain due to inversion of Ir-d and Se-p states.

  5. Breeding of a xylose-fermenting hybrid strain by mating genetically engineered haploid strains derived from industrial Saccharomyces cerevisiae.

    Science.gov (United States)

    Inoue, Hiroyuki; Hashimoto, Seitaro; Matsushika, Akinori; Watanabe, Seiya; Sawayama, Shigeki

    2014-12-01

    The industrial Saccharomyces cerevisiae IR-2 is a promising host strain to genetically engineer xylose-utilizing yeasts for ethanol fermentation from lignocellulosic hydrolysates. Two IR-2-based haploid strains were selected based upon the rate of xylulose fermentation, and hybrids were obtained by mating recombinant haploid strains harboring heterogeneous xylose dehydrogenase (XDH) (wild-type NAD(+)-dependent XDH or engineered NADP(+)-dependent XDH, ARSdR), xylose reductase (XR) and xylulose kinase (XK) genes. ARSdR in the hybrids selected for growth rates on yeast extract-peptone-dextrose (YPD) agar and YP-xylose agar plates typically had a higher activity than NAD(+)-dependent XDH. Furthermore, the xylose-fermenting performance of the hybrid strain SE12 with the same level of heterogeneous XDH activity was similar to that of a recombinant strain of IR-2 harboring a single set of genes, XR/ARSdR/XK. These results suggest not only that the recombinant haploid strains retain the appropriate genetic background of IR-2 for ethanol production from xylose but also that ARSdR is preferable for xylose fermentation.

  6. Demethoxycurcumin inhibited human epithelia ovarian cancer cells' growth via up-regulating miR-551a.

    Science.gov (United States)

    Du, Zhenhua; Sha, Xianqun

    2017-03-01

    Curcumin is a natural agent that has ability to dampen tumor cells' growth. However, the natural form of curcumin is prone to degrade and unstable in vitro. Here, we demonstrated that demethoxycurcumin (a curcumin-related demethoxy compound) could inhibit cell proliferation and induce apoptosis of ovarian cancer cells. Moreover, IRS2/PI3K/Akt axis was inactivated in cells treated with demethoxycurcumin. Quantitative real-time reverse transcription polymerase chain reaction demonstrated that miR-551a was down-regulated in ovarian cancer tissues and ovarian cancer cell lines. Over-expression of miR-551a inhibited cell proliferation and induced apoptosis of ovarian cancer cells, whereas down-regulation of miR-551a exerted the opposite function. Luciferase assays confirmed that there was a binding site of miR-551a in IRS2, and we found that miR-551a exerted tumor-suppressive function by targeting IRS2 in ovarian cancer cells. Remarkably, miR-551a was up-regulated in the cells treated with demethoxycurcumin, and demethoxycurcumin suppressed IRS2 by restoration of miR-551a. In conclusion, demethoxycurcumin hindered ovarian cancer cells' malignant progress via up-regulating miR-551a.

  7. Metabolic Syndrome, Insulin Resistance and Cognitive Dysfunction: Does your metabolic profile affect your brain?

    DEFF Research Database (Denmark)

    Neergaard, Jesper S; Møller, Katrine Dragsbæk; Christiansen, Claus

    2017-01-01

    with 44% (9%-91%) larger probability of developing cognitive dysfunction. In addition subjects above the HOMA-IR threshold (HOMA-IR > 2.6) had 47% (9%-99%) larger odds of cognitive dysfunction. The associations could indicate that a significant proportion of dementia cases in women is likely...

  8. Journal of Genetics | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    Polycystic ovary syndrome (PCOS) is the most common and a complex female endocrine disorder, and is one of the leading cause of female infertility. Here, we aimed to investigate the association of single-nucleotide polymorphism of INS, INSR, IRS1, IRS2, PPAR-G and CAPN10 gene in the pathogenesis of PCOS.

  9. UV-light promoted C-H bond activation of benzene and fluorobenzenes by an iridium(i) pincer complex.

    Science.gov (United States)

    Hauser, Simone A; Emerson-King, Jack; Habershon, Scott; Chaplin, Adrian B

    2017-03-28

    Iridium(i) carbonyl complex [Ir(2,6-(P t Bu 2 CH 2 ) 2 C 6 H 3 )(CO)] undergoes reversible C-H bond activation of benzene and a series of fluorobenzenes on UV irradiation. Exclusive ortho-selectivity is observed in reactions of fluorobenzene and 1,2-difluorobenzene.

  10. UV-light promoted C–H bond activation of benzene and fluorobenzenes by an iridium(i) pincer complex

    OpenAIRE

    Hauser, Simone A.; Emerson-King, Jack; Habershon, Scott; Chaplin, Adrian B.

    2017-01-01

    Iridium(I) carbonyl complex [Ir(2,6-(PtBu2CH2)2C6H3)(CO)] undergoes reversible C–H bond activation of benzene and a series of fluorobenzenes on UV irradiation. Exclusive ortho-selectivity is observed in reactions of fluorobenzene and 1,2-difluorobenzene.\\ud \\ud

  11. Comprehensive regional and temporal gene expression profiling of the rat brain during the first 24 h after experimental stroke identifies dynamic ischemia-induced gene expression patterns, and reveals a biphasic activation of genes in surviving tissue

    DEFF Research Database (Denmark)

    Rickhag, Karl Mattias; Wieloch, Tadeusz; Gidö, Gunilla

    2006-01-01

    middle cerebral artery occlusion in the rat. K-means cluster analysis revealed two distinct biphasic gene expression patterns that contained 44 genes (including 18 immediate early genes), involved in cell signaling and plasticity (i.e. MAP2K7, Sprouty2, Irs-2, Homer1, GPRC5B, Grasp). The first gene...

  12. Multiple soliton compression stages in mid-IR gas-filled hollow-core fibers

    DEFF Research Database (Denmark)

    Habib, Md Selim; Markos, Christos; Bang, Ole

    2017-01-01

    The light confinement inside hollow-core (HC) fibers filled with noble gases constitutes an efficient route to study interesting soliton-plasma dynamics [1]. More recently, plasma-induced soliton splitting at the self-compression point was observed in a gas-filled fiber in the near-IR [2]. However...

  13. Herpes zoster in psoriasis patients treated with tofacitinib

    DEFF Research Database (Denmark)

    Winthrop, Kevin L; Lebwohl, Mark; Cohen, Arnon D

    2017-01-01

    (LTE) data from the tofacitinib development program in psoriasis to calculate HZ incidence rates (IR; events per 100 patient-years); potential HZ risk factors were evaluated using Cox-proportional hazard models. RESULTS: One hundred thirty (3.6%) patients on tofacitinib (IR 2.55), no patients...

  14. A NEW RADIO RECOMBINATION LINE MASER OBJECT TOWARD THE MonR2 H II REGION

    Energy Technology Data Exchange (ETDEWEB)

    Jimenez-Serra, I.; Zhang, Q.; Dierickx, M.; Patel, N. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Baez-Rubio, A.; Rivilla, V. M.; Martin-Pintado, J., E-mail: ijimenez-serra@cfa.harvard.edu, E-mail: qzhang@cfa.harvard.edu, E-mail: mdierickx@cfa.harvard.edu, E-mail: npatel@cfa.harvard.edu, E-mail: ryvendel@gmail.com, E-mail: jmartin@cab.inta-csic.es, E-mail: baezra@cab.inta-csic.es [Centro de Astrobiologia (CSIC/INTA), Ctra. de Torrejon a Ajalvir km 4, E-28850 Torrejon de Ardoz, Madrid (Spain)

    2013-02-10

    We report the detection of a new radio recombination line (RRL) maser object toward the IRS2 source in the MonR2 ultracompact H II region. The continuum emission at 1.3 mm and 0.85 mm and the H30{alpha} and H26{alpha} lines were observed with the Submillimeter Array (SMA) at angular resolutions of {approx}0.''5-3''. The SMA observations show that the MonR2-IRS2 source is very compact and remains unresolved at spatial scales {<=}400 AU. Its continuum power spectrum at millimeter wavelengths is almost flat ({alpha} = -0.16, with S{sub {nu}}{proportional_to}{nu}{sup {alpha}}), indicating that this source is dominated by optically thin free-free emission. The H30{alpha} and H26{alpha} RRL emission is also compact and peaks toward the position of the MonR2-IRS2 source. The measured RRL profiles are double peaked with the H26{alpha} line showing a clear asymmetry in its spectrum. Since the derived line-to-continuum flux ratios ({approx}80 and 180 km s{sup -1} for H30{alpha} and H26{alpha}, respectively) exceed the LTE predictions, the RRLs toward MonR2-IRS2 are affected by maser amplification. The amplification factors are, however, smaller than those found toward the emission-line star MWC349A, indicating that MonR2-IRS2 is a weakly amplified maser. Radiative transfer modeling of the RRL emission toward this source shows that the RRL masers arise from a dense and collimated jet embedded in a cylindrical ionized wind, oriented nearly along the direction of the line of sight. High-angular resolution observations at submillimeter wavelengths are needed to unveil weakly amplified RRL masers in very young massive stars.

  15. Dysregulated hepatic expression of glucose transporters in chronic disease: contribution of semicarbazide-sensitive amine oxidase to hepatic glucose uptake.

    Science.gov (United States)

    Karim, Sumera; Liaskou, Evaggelia; Fear, Janine; Garg, Abhilok; Reynolds, Gary; Claridge, Lee; Adams, David H; Newsome, Philip N; Lalor, Patricia F

    2014-12-15

    Insulin resistance is common in patients with chronic liver disease (CLD). Serum levels of soluble vascular adhesion protein-1 (VAP-1) are also increased in these patients. The amine oxidase activity of VAP-1 stimulates glucose uptake via translocation of transporters to the cell membrane in adipocytes and smooth muscle cells. We aimed to document human hepatocellular expression of glucose transporters (GLUTs) and to determine if VAP-1 activity influences receptor expression and hepatic glucose uptake. Quantitative PCR and immunocytochemistry were used to study human liver tissue and cultured cells. We also used tissue slices from humans and VAP-1-deficient mice to assay glucose uptake and measure hepatocellular responses to stimulation. We report upregulation of GLUT1, -3, -5, -6, -7, -8, -9, -10, -11, -12, and -13 in CLD. VAP-1 expression and enzyme activity increased in disease, and provision of substrate to hepatic VAP-1 drives hepatic glucose uptake. This effect was sensitive to inhibition of VAP-1 and could be recapitulated by H2O2. VAP-1 activity also altered expression and subcellular localization of GLUT2, -4, -9, -10, and -13. Therefore, we show, for the first time, alterations in hepatocellular expression of glucose and fructose transporters in CLD and provide evidence that the semicarbazide-sensitive amine oxidase activity of VAP-1 modifies hepatic glucose homeostasis and may contribute to patterns of GLUT expression in chronic disease. Copyright © 2014 the American Physiological Society.

  16. Perinatal exposure to germinated brown rice and its gamma amino-butyric acid-rich extract prevents high fat diet-induced insulin resistance in first generation rat offspring

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    Hadiza Altine Adamu

    2016-02-01

    Full Text Available Background: Evidence suggests perinatal environments influence the risk of developing insulin resistance. Objective: The present study was aimed at determining the effects of intrauterine exposure to germinated brown rice (GBR and GBR-derived gamma (γ aminobutyric acid (GABA extract on epigenetically mediated high fat diet–induced insulin resistance. Design: Pregnant Sprague Dawley rats were fed high-fat diet (HFD, HFD+GBR, or HFD+GABA throughout pregnancy until 4 weeks postdelivery. The pups were weighed weekly and maintained on normal pellet until 8 weeks postdelivery. After sacrifice, biochemical markers of obesity and insulin resistance including oral glucose tolerance test, adiponectin, leptin, and retinol binding protein-4 (RBP4 were measured. Hepatic gene expression changes and the global methylation and histone acetylation levels were also evaluated. Results: Detailed analyses revealed that mothers given GBR and GABA extract, and their offspring had increased adiponectin levels and reduced insulin, homeostasis model assessment of insulin resistance, leptin, oxidative stress, and RBP4 levels, while their hepatic mRNA levels of GLUT2 and IPF1 were increased. Furthermore, GBR and GABA extract lowered global DNA methylation levels and modulated H3 and H4 acetylation levels. Conclusions: These results showed that intrauterine exposure to GBR-influenced metabolic outcomes in offspring of rats with underlying epigenetic changes and transcriptional implications that led to improved glucose homeostasis.

  17. Glucosensing capacity in rainbow trout liver displays day-night variations possibly related to melatonin action.

    Science.gov (United States)

    Conde-Sieira, Marta; Patiño, Marcos A López; Míguez, Jesús M; Soengas, José L

    2012-09-01

    To assess whether the glucosensing capacity in peripheral (liver and Brockmann bodies) and central (hypothalamus and hindbrain) locations of rainbow trout displays day-night variations in its response to changes in circulating glucose levels, we evaluated the response of parameters related to glucosensing [glucose, glycogen and glucose 6-phosphate levels, activities of glucokinase (GK), glycogen synthetase (GSase) and pyruvate kinase (PK), and mRNA abundance of GK, glucose transporter 2 (GLUT2), and K(ATP) channel subunits Kir6.x-like and sulfonylurea receptor (SUR)-like] in fish subjected to hyperglycemic treatment under night or day conditions. No day-night significant variations were noticed in the glucosensing capacity of the hypothalamus, hindbrain and Brockmann bodies. In contrast, a clear differential response was noticed in the liver, where glucose levels, GK activity (and mRNA levels) and GSase activity displayed increased values during the day in hyperglycemic fish compared with controls, and lower (GK mRNA levels) or non-existent (glucose, GK and GSase activities, and Kir6.x-like mRNA levels) values during the night. A similar decrease in parameters related to glucosensing in the liver was observed when fish under day conditions were treated with melatonin, suggesting a modulatory role of melatonin in day-night changes of the glucosensing response in the same tissue.

  18. Intestinal Transport Characteristics and Metabolism of C-Glucosyl Dihydrochalcone, Aspalathin

    Directory of Open Access Journals (Sweden)

    Sandra Bowles

    2017-03-01

    Full Text Available Insight into the mechanisms of intestinal transport and metabolism of aspalathin will provide important information for dose optimisation, in particular for studies using mouse models. Aspalathin transportation across the intestinal barrier (Caco-2 monolayer tested at 1–150 µM had an apparent rate of permeability (Papp typical of poorly absorbed compounds (1.73 × 10−6 cm/s. Major glucose transporters, sodium glucose linked transporter 1 (SGLT1 and glucose transporter 2 (GLUT2, and efflux protein (P-glycoprotein, PgP (1.84 × 10−6 cm/s; efflux ratio: 1.1 were excluded as primary transporters, since the Papp of aspalathin was not affected by the presence of specific inhibitors. The Papp of aspalathin was also not affected by constituents of aspalathin-enriched rooibos extracts, but was affected by high glucose concentration (20.5 mM, which decreased the Papp value to 2.9 × 10−7 cm/s. Aspalathin metabolites (sulphated, glucuronidated and methylated were found in mouse urine, but not in blood, following an oral dose of 50 mg/kg body weight of the pure compound. Sulphates were the predominant metabolites. These findings suggest that aspalathin is absorbed and metabolised in mice to mostly sulphate conjugates detected in urine. Mechanistically, we showed that aspalathin is not actively transported by the glucose transporters, but presumably passes the monolayer paracellularly.

  19. Human Islet Amyloid Polypeptide Transgenic Mice: In Vivo and Ex Vivo Models for the Role of hIAPP in Type 2 Diabetes Mellitus

    Directory of Open Access Journals (Sweden)

    J. W. M. Höppener

    2008-01-01

    Full Text Available Human islet amyloid polypeptide (hIAPP, a pancreatic islet protein of 37 amino acids, is the main component of islet amyloid, seen at autopsy in patients with type 2 diabetes mellitus (DM2. To investigate the roles of hIAPP and islet amyloid in DM2, we generated transgenic mice expressing hIAPP in their islet beta cells. In this study, we found that after a long-term, high-fat diet challenge islet amyloid was observed in only 4 of 19 hIAPP transgenic mice. hIAPP transgenic females exhibited severe glucose intolerance, which was associated with a downregulation of GLUT-2 mRNA expression. In isolated islets from hIAPP males cultured for 3 weeks on high-glucose medium, the percentage of amyloid containing islets increased from 5.5% to 70%. This ex vivo system will allow a more rapid, convenient, and specific study of factors influencing islet amyloidosis as well as of therapeutic strategies to interfere with this pathological process.

  20. Generation of thalamic neurons from mouse embryonic stem cells.

    Science.gov (United States)

    Shiraishi, Atsushi; Muguruma, Keiko; Sasai, Yoshiki

    2017-04-01

    The thalamus is a diencephalic structure that plays crucial roles in relaying and modulating sensory and motor information to the neocortex. The thalamus develops in the dorsal part of the neural tube at the level of the caudal forebrain. However, the molecular mechanisms that are essential for thalamic differentiation are still unknown. Here, we have succeeded in generating thalamic neurons from mouse embryonic stem cells (mESCs) by modifying the default method that induces the most-anterior neural type in self-organizing culture. A low concentration of the caudalizing factor insulin and a MAPK/ERK kinase inhibitor enhanced the expression of the caudal forebrain markers Otx2 and Pax6. BMP7 promoted an increase in thalamic precursors such as Tcf7l2 + /Gbx2 + and Tcf7l2 + /Olig3 + cells. mESC thalamic precursors began to express the glutamate transporter vGlut2 and the axon-specific marker VGF, similar to mature projection neurons. The mESC thalamic neurons extended their axons to cortical layers in both organotypic culture and subcortical transplantation. Thus, we have identified the minimum elements sufficient for in vitro generation of thalamic neurons. These findings expand our knowledge of thalamic development. © 2017. Published by The Company of Biologists Ltd.

  1. High-fat, carbohydrate-free diet markedly aggravates obesity but prevents beta-cell loss and diabetes in the obese, diabetes-susceptible db/db strain.

    Science.gov (United States)

    Mirhashemi, Farshad; Kluth, Oliver; Scherneck, Stephan; Vogel, Heike; Kluge, Reinhart; Schurmann, Annette; Joost, Hans-Georg; Neschen, Susanne

    2008-01-01

    We have previously reported that a high-fat, carbohydrate-free diet prevents diabetes and beta-cell destruction in the New Zealand Obese (NZO) mouse strain. Here we investigated the effect of diets with and without carbohydrates on obesity and development of beta-cell failure in a second mouse model of type 2 diabetes, the db/db mouse. When kept on a carbohydrate-containing standard (SD; with (w/w) 5.1, 58.3, and 17.6% fat, carbohydrates and protein, respectively) or high-fat diet (HFD; 14.6, 46.7 and 17.1%), db/db mice developed severe diabetes (blood glucose >20 mmol/l, weight loss, polydipsia and polyurea) associated with a selective loss of pancreatic beta-cells, reduced GLUT2 expression in the remaining beta-cells, and reduced plasma insulin levels. In contrast, db/db mice kept on a high-fat, carbohydrate-free diet (CFD; with 30.2 and 26.4% (w/w) fat or protein) did not develop diabetes and exhibited near-normal, hyperplastic islets in spite of a morbid obesity (fat content >60%) associated with hyperinsulinaemia. These data indicate that in genetically different mouse models of obesity-associated diabetes, obesity and dietary fat are not sufficient, and dietary carbohydrates are required, for beta-cell destruction.

  2. Anti-hyperglycemic and insulin sensitizer effects of turmeric and its principle constituent curcumin.

    Science.gov (United States)

    Ghorbani, Zeinab; Hekmatdoost, Azita; Mirmiran, Parvin

    2014-10-01

    Turmeric is obtained from the plant Curcuma longa L; its major constituent, curcumin, is a polyphenol with multiple effects which can modulate some signaling pathways. Insulin resistance is a major risk factor for chronic diseases such as type 2 diabetes, atherosclerotic, metabolic syndrome and cardiovascular disease. In addition, Insulin resistance in peripheral tissue is one of the most important reasons of hyperglycemia which can cause global or systemic effects. The present study reviewed studies published in PubMed from 1998 to 2013, indicating the role of curcumin in attenuation of many pathophysiological processes involved in development and progression of hyperglycemia and insulin resistance. Curcumin can reduce blood glucose level by reducing the hepatic glucose production, suppression of hyperglycemia-induced inflammatory state, stimulation of glucose uptake by up-regulation of GLUT4, GLUT2 and GLUT3 genes expressions, activation of AMP kinase, promoting the PPAR ligand-binding activity, stimulation of insulin secretion from pancreatic tissues, improvement in pancreatic cell function, and reduction of insulin resistance. Curcumin has antihyperglycemic and insulin sensitizer effects. Thereby, more studies evaluating the effects of curcumin on hyperglycemic state and insulin resistance in related disorders such as diabetes are recommended.

  3. [Contribution of the kidney to glucose homeostasis].

    Science.gov (United States)

    Segura, Julián; Ruilope, Luis Miguel

    2013-09-01

    The kidney is involved in glucose homeostasis through three major mechanisms: renal gluconeogenesis, renal glucose consumption, and glucose reabsorption in the proximal tubule. Glucose reabsorption is one of the most important physiological functions of the kidney, allowing full recovery of filtered glucose, elimination of glucose from the urine, and prevention of calorie loss. Approximately 90% of the glucose is reabsorbed in the S1 segment of the proximal tubule, where glucose transporter-2 (GLUT2) and sodium-glucose transporter-2 (SGLT2) are located, while the remaining 10% is reabsorbed in the S3 segment by SGLT1 and GLUT1 transporters. In patients with hyperglycemia, the kidney continues to reabsorb glucose, thus maintaining hyperglycemia. Most of the renal glucose reabsorption is mediated by SGLT2. Several experimental and clinical studies suggest that pharmacological blockade of this transporter might be beneficial in the management of hyperglycemia in patients with type 2 diabetes. Copyright © 2013 Elsevier España, S.L. All rights reserved.

  4. High Dietary Fructose: Direct or Indirect Dangerous Factors Disturbing Tissue and Organ Functions.

    Science.gov (United States)

    Zhang, Dong-Mei; Jiao, Rui-Qing; Kong, Ling-Dong

    2017-03-29

    High dietary fructose is a major contributor to insulin resistance and metabolic syndrome, disturbing tissue and organ functions. Fructose is mainly absorbed into systemic circulation by glucose transporter 2 (GLUT2) and GLUT5, and metabolized in liver to produce glucose, lactate, triglyceride (TG), free fatty acid (FFA), uric acid (UA) and methylglyoxal (MG). Its extrahepatic absorption and metabolism also take place. High levels of these metabolites are the direct dangerous factors. During fructose metabolism, ATP depletion occurs and induces oxidative stress and inflammatory response, disturbing functions of local tissues and organs to overproduce inflammatory cytokine, adiponectin, leptin and endotoxin, which act as indirect dangerous factors. Fructose and its metabolites directly and/or indirectly cause oxidative stress, chronic inflammation, endothelial dysfunction, autophagy and increased intestinal permeability, and then further aggravate the metabolic syndrome with tissue and organ dysfunctions. Therefore, this review addresses fructose-induced metabolic syndrome, and the disturbance effects of direct and/or indirect dangerous factors on the functions of liver, adipose, pancreas islet, skeletal muscle, kidney, heart, brain and small intestine. It is important to find the potential correlations between direct and/or indirect risk factors and healthy problems under excess dietary fructose consumption.

  5. Glucose, epithelium, and enteric nervous system: dialogue in the dark.

    Science.gov (United States)

    Pfannkuche, H; Gäbel, G

    2009-06-01

    The gastrointestinal epithelium is in close contact with the various components of the chymus, including nutrients, bacteria and toxins. The epithelial barrier has to decide which components are effectively absorbed and which components are extruded. In the small intestine, a nutrient like glucose is mainly absorbed by the sodium linked glucose cotransporter 1 (SGLT1) and the glucose transporter 2 (GLUT2). The expression and activity of both transport proteins is directly linked to the amount of intraluminal glucose. Besides the direct interaction between glucose and the enterocytes, glucose also stimulates different sensory mechanisms within the intestinal wall. The most important types of cells involved in the sensing of intraluminal contents are enteroendocrine cells and neurones of the enteric nervous system. Regarding glucosensing, a distinct type of enteroendocrine cells, the enterochromaffine (EC) cells are involved. Excitation of EC cells by intraluminal glucose results in the release of serotonin (5-HT), which modulates epithelial functions and activates enteric secretomotorneurones. Enteric neurones are not only activated by 5-HT, but also directly by glucose. The activation of different cell types and the subsequent crosstalk between these cells may trigger appropriate absorptive and secretory processes within the intestine.

  6. Liraglutide Modulates Appetite and Body Weight Via GLP-1R-Expressing Glutamatergic Neurons.

    Science.gov (United States)

    Adams, Jessica M; Pei, Hongjuan; Sandoval, Darleen A; Seeley, Randy J; Chang, Rui B; Liberles, Stephen D; Olson, David P

    2018-05-18

    Glucagon-like peptide-1 receptor (GLP-1R) agonists are FDA-approved weight loss drugs. Despite their widespread use, the sites of action through which GLP-1R agonists (GLP1RAs) impact appetite and body weight are still not fully understood. Here, we determined whether GLP-1Rs in either GABAergic or glutamatergic neurons are necessary for the acute and chronic effects of the GLP1RA liraglutide on food intake, visceral illness, body weight and neural network activation. We found that mice lacking GLP-1Rs in vGAT -expressing GABAergic neurons responded identically to controls in all parameters measured, whereas deletion of GLP-1Rs in vGlut2 -expressing glutamatergic neurons eliminated liraglutide-induced weight loss and visceral illness and severely attenuated its effects on feeding. Concomitantly, deletion of GLP-1Rs from glutamatergic neurons completely abolished the neural network activation observed after liraglutide administration. We conclude that liraglutide activates a dispersed but discrete neural network to mediate its physiological effects, and that these effects require GLP-1R expression on glutamatergic but not GABAergic neurons. © 2018 by the American Diabetes Association.

  7. Transport of the Glucosamine-Derived Browning Product Fructosazine (Polyhydroxyalkylpyrazine) Across the Human Intestinal Caco-2 Cell Monolayer: Role of the Hexose Transporters.

    Science.gov (United States)

    Bhattacherjee, Abhishek; Hrynets, Yuliya; Betti, Mirko

    2017-06-14

    The transport mechanism of fructosazine, a glucosamine self-condensation product, was investigated using a Caco-2 cell model. Fructosazine transport was assessed by measuring the bidirectional permeability coefficient across Caco-2 cells. The mechanism of transport was evaluated using phlorizin, an inhibitor of sodium-dependent glucose cotransporters (SGLT) 1 and 2, phloretin and quercetin, inhibitors of glucose transporters (GLUT) 1 and 2, transcytosis inhibitor wortmannin, and gap junction disruptor cytochalasin D. The role of hexose transporters was further studied using downregulated or overexpressed cell lines. The apparent permeability (P a,b ) of fructosazine was 1.30 ± 0.02 × 10 -6 cm/s. No significant (p > 0.05) effect was observed in fructosazine transport by adding wortmannin and cytochalasin D. The presence of phlorizin, phloretin, and quercetin decreased fructosazine transport. The downregulated GLUT cells line was unable to transport fructosazine. In human intestinal epithelial Caco-2 cells, GLUT1 or GLUT2 and SGLT are mainly responsible for fructosazine transport.

  8. Fibronectin and laminin promote differentiation of human mesenchymal stem cells into insulin producing cells through activating Akt and ERK

    Directory of Open Access Journals (Sweden)

    Chiou Shih-Hwa

    2010-07-01

    Full Text Available Abstract Background Islet transplantation provides a promising cure for Type 1 diabetes; however it is limited by a shortage of pancreas donors. Bone marrow-derived multipotent mesenchymal stem cells (MSCs offer renewable cells for generating insulin-producing cells (IPCs. Methods We used a four-stage differentiation protocol, containing neuronal differentiation and IPC-conversion stages, and combined with pellet suspension culture to induce IPC differentiation. Results Here, we report adding extracellular matrix proteins (ECM such as fibronectin (FN or laminin (LAM enhances pancreatic differentiation with increases in insulin and Glut2 gene expressions, proinsulin and insulin protein levels, and insulin release in response to elevated glucose concentration. Adding FN or LAM induced activation of Akt and ERK. Blocking Akt or ERK by adding LY294002 (PI3K specific inhibitor, PD98059 (MEK specific inhibitor or knocking down Akt or ERK failed to abrogate FN or LAM-induced enhancement of IPC differentiation. Only blocking both of Akt and ERK or knocking down Akt and ERK inhibited the enhancement of IPC differentiation by adding ECM. Conclusions These data prove IPC differentiation by MSCs can be modulated by adding ECM, and these stimulatory effects were mediated through activation of Akt and ERK pathways.

  9. Cloning Expeditions: Risky but Rewarding

    Science.gov (United States)

    2013-01-01

    In the 1980s, a good part of my laboratory was using the then-new recombinant DNA techniques to clone and characterize many important cell surface membrane proteins: GLUT1 (the red cell glucose transporter) and then GLUT2 and GLUT4, the red cell anion exchange protein (Band 3), asialoglycoprotein receptor subunits, sucrase-isomaltase, the erythropoietin receptor, and two of the subunits of the transforming growth factor β (TGF-β) receptor. These cloned genes opened many new fields of basic research, including membrane insertion and trafficking of transmembrane proteins, signal transduction by many members of the cytokine and TGF-β families of receptors, and the cellular physiology of glucose and anion transport. They also led to many insights into the molecular biology of several cancers, hematopoietic disorders, and diabetes. This work was done by an exceptional group of postdocs and students who took exceptionally large risks in developing and using novel cloning technologies. Unsurprisingly, all have gone on to become leaders in the fields of molecular cell biology and molecular medicine. PMID:24061478

  10. Metabolic Symbiosis Enables Adaptive Resistance to Anti-angiogenic Therapy that Is Dependent on mTOR Signaling

    Directory of Open Access Journals (Sweden)

    Elizabeth Allen

    2016-05-01

    Full Text Available Therapeutic targeting of tumor angiogenesis with VEGF inhibitors results in demonstrable, but transitory efficacy in certain human tumors and mouse models of cancer, limited by unconventional forms of adaptive/evasive resistance. In one such mouse model, potent angiogenesis inhibitors elicit compartmental reorganization of cancer cells around remaining blood vessels. The glucose and lactate transporters GLUT1 and MCT4 are induced in distal hypoxic cells in a HIF1α-dependent fashion, indicative of glycolysis. Tumor cells proximal to blood vessels instead express the lactate transporter MCT1, and p-S6, the latter reflecting mTOR signaling. Normoxic cancer cells import and metabolize lactate, resulting in upregulation of mTOR signaling via glutamine metabolism enhanced by lactate catabolism. Thus, metabolic symbiosis is established in the face of angiogenesis inhibition, whereby hypoxic cancer cells import glucose and export lactate, while normoxic cells import and catabolize lactate. mTOR signaling inhibition disrupts this metabolic symbiosis, associated with upregulation of the glucose transporter GLUT2.

  11. Intestinal Transport Characteristics and Metabolism of C-Glucosyl Dihydrochalcone, Aspalathin.

    Science.gov (United States)

    Bowles, Sandra; Joubert, Elizabeth; de Beer, Dalene; Louw, Johan; Brunschwig, Christel; Njoroge, Mathew; Lawrence, Nina; Wiesner, Lubbe; Chibale, Kelly; Muller, Christo

    2017-03-30

    Insight into the mechanisms of intestinal transport and metabolism of aspalathin will provide important information for dose optimisation, in particular for studies using mouse models. Aspalathin transportation across the intestinal barrier (Caco-2 monolayer) tested at 1-150 µM had an apparent rate of permeability (P app ) typical of poorly absorbed compounds (1.73 × 10 -6 cm/s). Major glucose transporters, sodium glucose linked transporter 1 (SGLT1) and glucose transporter 2 (GLUT2), and efflux protein (P-glycoprotein, PgP) (1.84 × 10 -6 cm/s; efflux ratio: 1.1) were excluded as primary transporters, since the P app of aspalathin was not affected by the presence of specific inhibitors. The P app of aspalathin was also not affected by constituents of aspalathin-enriched rooibos extracts, but was affected by high glucose concentration (20.5 mM), which decreased the P app value to 2.9 × 10 -7 cm/s. Aspalathin metabolites (sulphated, glucuronidated and methylated) were found in mouse urine, but not in blood, following an oral dose of 50 mg/kg body weight of the pure compound. Sulphates were the predominant metabolites. These findings suggest that aspalathin is absorbed and metabolised in mice to mostly sulphate conjugates detected in urine. Mechanistically, we showed that aspalathin is not actively transported by the glucose transporters, but presumably passes the monolayer paracellularly.

  12. High Dietary Fructose: Direct or Indirect Dangerous Factors Disturbing Tissue and Organ Functions

    Directory of Open Access Journals (Sweden)

    Dong-Mei Zhang

    2017-03-01

    Full Text Available High dietary fructose is a major contributor to insulin resistance and metabolic syndrome, disturbing tissue and organ functions. Fructose is mainly absorbed into systemic circulation by glucose transporter 2 (GLUT2 and GLUT5, and metabolized in liver to produce glucose, lactate, triglyceride (TG, free fatty acid (FFA, uric acid (UA and methylglyoxal (MG. Its extrahepatic absorption and metabolism also take place. High levels of these metabolites are the direct dangerous factors. During fructose metabolism, ATP depletion occurs and induces oxidative stress and inflammatory response, disturbing functions of local tissues and organs to overproduce inflammatory cytokine, adiponectin, leptin and endotoxin, which act as indirect dangerous factors. Fructose and its metabolites directly and/or indirectly cause oxidative stress, chronic inflammation, endothelial dysfunction, autophagy and increased intestinal permeability, and then further aggravate the metabolic syndrome with tissue and organ dysfunctions. Therefore, this review addresses fructose-induced metabolic syndrome, and the disturbance effects of direct and/or indirect dangerous factors on the functions of liver, adipose, pancreas islet, skeletal muscle, kidney, heart, brain and small intestine. It is important to find the potential correlations between direct and/or indirect risk factors and healthy problems under excess dietary fructose consumption.

  13. Intermittent fasting modulation of the diabetic syndrome in sand rats. III. Post-mortem investigations.

    Science.gov (United States)

    Belkacemi, Louiza; Selselet-Attou, Ghalem; Bulur, Nurdan; Louchami, Karim; Sener, Abdullah; Malaisse, Willy J

    2011-01-01

    The present report concerns several post-mortem variables examined in sand rats that were either maintained on a vegetal diet (control animals) or exposed first during a 20-day transition period to a mixed diet consisting of a fixed amount of a hypercaloric food and decreasing amounts of the vegetal food and then to a 30-day experimental period of exposure to the hypercaloric food. During the latter period, all animals were either given free access to food or fasting daily for 15 h, i.e. from 5.00 p.m. to 8.00 a.m. The body weight, liver wet weight, pancreas wet weight, plasma glucose and haemoglobin A1c concentration, plasma insulin concentration, insulinogenic index, insulin resistance HOMA, plasma cholesterol and triglyceride concentration, liver triglyceride and phospholipid content were all measured. Pancreatic islet (insulin, GLUT2) and liver (lipid droplets) histology were also examined. The main findings consisted in a lower body weight of fasting than non-fasting animals, a higher liver weight in non-diabetic and diabetic rats than in control non-fasting (but not so in fasting) animals, a decrease of pancreas weight in non-diabetic and diabetic as distinct from control animals, a fasting-induced decrease in plasma glucose, plasma insulin and insulin resistance HOMA, plasma cholesterol and triglyceride concentration and triglyceride liver content.

  14. Sodium-glucose co-transporter (SGLT) and glucose transporter (GLUT) expression in the kidney of type 2 diabetic subjects.

    Science.gov (United States)

    Norton, Luke; Shannon, Christopher E; Fourcaudot, Marcel; Hu, Cheng; Wang, Niansong; Ren, Wei; Song, Jun; Abdul-Ghani, Muhammad; DeFronzo, Ralph A; Ren, Jimmy; Jia, Weiping

    2017-09-01

    The sodium-glucose co-transporters (SGLTs) are responsible for the tubular reabsorption of filtered glucose from the kidney into the bloodstream. The inhibition of SGLT2-mediated glucose reabsorption is a novel and highly effective strategy to alleviate hyperglycaemia in patients with type 2 diabetes mellitus (T2DM). However, the effectiveness of SGLT2 inhibitor therapy is diminished due, in part, to a compensatory increase in the maximum reabsorptive capacity (Tm) for glucose in patients with T2DM. We hypothesized that this increase in Tm could be explained by an increase in the tubular expression of SGLT and glucose transporters (GLUT) in these patients. To examine this, we obtained human kidney biopsy specimens from patients with or without T2DM and examined the mRNA expression of SGLTs and GLUTs. The expression of SGLT1 is markedly increased in the kidney of patients with T2DM, and SGLT1 mRNA is highly and significantly correlated with fasting and postprandial plasma glucose and HbA1c. In contrast, our data demonstrate that the levels of SGLT2 and GLUT2 mRNA are downregulated in diabetic patients, but not to a statistically significant level. These important findings are clinically significant and may have implications for the treatment of T2DM using strategies that target SGLT transporters in the kidney. © 2017 John Wiley & Sons Ltd.

  15. Dendrobium nobile Lindl. alkaloids regulate metabolism gene expression in livers of mice.

    Science.gov (United States)

    Xu, Yun-Yan; Xu, Ya-Sha; Wang, Yuan; Wu, Qin; Lu, Yuan-Fu; Liu, Jie; Shi, Jing-Shan

    2017-10-01

    In our previous studies, Dendrobium nobile Lindl. alkaloids (DNLA) has been shown to have glucose-lowering and antihyperlipidaemia effects in diabetic rats, in rats fed with high-fat diets, and in mice challenged with adrenaline. This study aimed to examine the effects of DNLA on the expression of glucose and lipid metabolism genes in livers of mice. Mice were given DNLA at doses of 10-80 mg/kg, po for 8 days, and livers were removed for total RNA and protein isolation to perform real-time RT-PCR and Western blot analysis. Dendrobium nobile Lindl. alkaloids increased PGC1α at mRNA and protein levels and increased glucose metabolism gene Glut2 and FoxO1 expression. DNLA also increased the expression of fatty acid β-oxidation genes Acox1 and Cpt1a. The lipid synthesis regulator Srebp1 (sterol regulatory element-binding protein-1) was decreased, while the lipolysis gene ATGL was increased. Interestingly, DNLA increased the expression of antioxidant gene metallothionein-1 and NADPH quinone oxidoreductase-1 (Nqo1) in livers of mice. Western blot on selected proteins confirmed these changes including the increased expression of GLUT4 and PPARα. DNLA has beneficial effects on liver glucose and lipid metabolism gene expressions, and enhances the Nrf2-antioxidant pathway gene expressions, which could play integrated roles in regulating metabolic disorders. © 2017 Royal Pharmaceutical Society.

  16. The Role of Carbohydrate Response Element Binding Protein in Intestinal and Hepatic Fructose Metabolism

    Directory of Open Access Journals (Sweden)

    Katsumi Iizuka

    2017-02-01

    Full Text Available Many articles have discussed the relationship between fructose consumption and the incidence of obesity and related diseases. Fructose is absorbed in the intestine and metabolized in the liver to glucose, lactate, glycogen, and, to a lesser extent, lipids. Unabsorbed fructose causes bacterial fermentation, resulting in irritable bowl syndrome. Therefore, understanding the mechanisms underlying intestinal and hepatic fructose metabolism is important for the treatment of metabolic syndrome and fructose malabsorption. Carbohydrate response element binding protein (ChREBP is a glucose-activated transcription factor that controls approximately 50% of de novo lipogenesis in the liver. ChREBP target genes are involved in glycolysis (Glut2, liver pyruvate kinase, fructolysis (Glut5, ketohexokinase, and lipogenesis (acetyl CoA carboxylase, fatty acid synthase. ChREBP gene deletion protects against high sucrose diet-induced and leptin-deficient obesity, because Chrebp−/− mice cannot consume fructose or sucrose. Moreover, ChREBP contributes to some of the physiological effects of fructose on sweet taste preference and glucose production through regulation of ChREBP target genes, such as fibroblast growth factor-21 and glucose-6-phosphatase catalytic subunits. Thus, ChREBP might play roles in fructose metabolism. Restriction of excess fructose intake will be beneficial for preventing not only metabolic syndrome but also irritable bowl syndrome.

  17. Glucose and hypothalamic astrocytes: More than a fueling role?

    Science.gov (United States)

    Leloup, C; Allard, C; Carneiro, L; Fioramonti, X; Collins, S; Pénicaud, L

    2016-05-26

    Brain plays a central role in energy homeostasis continuously integrating numerous peripheral signals such as circulating nutrients, and in particular blood glucose level, a variable that must be highly regulated. Then, the brain orchestrates adaptive responses to modulate food intake and peripheral organs activity in order to achieve the fine tuning of glycemia. More than fifty years ago, the presence of glucose-sensitive neurons was discovered in the hypothalamus, but what makes them specific and identifiable still remains disconnected from their electrophysiological signature. On the other hand, astrocytes represent the major class of macroglial cells and are now recognized to support an increasing number of neuronal functions. One of these functions consists in the regulation of energy homeostasis through neuronal fueling and nutrient sensing. Twenty years ago, we discovered that the glucose transporter GLUT2, the canonical "glucosensor" of the pancreatic beta-cell together with the glucokinase, was also present in astrocytes and participated in hypothalamic glucose sensing. Since then, many studies have identified other actors and emphasized the astroglial participation in this mechanism. Growing evidence suggest that astrocytes form a complex network and have to be considered as spatially coordinated and regulated metabolic units. In this review we aim to provide an updated view of the molecular and respective cellular pathways involved in hypothalamic glucose sensing, and their relevance in physiological and pathological states. Copyright © 2015 IBRO. Published by Elsevier Ltd. All rights reserved.

  18. The effect of Liuwei Dihuang decoction on PI3K/Akt signaling pathway in liver of type 2 diabetes mellitus (T2DM) rats with insulin resistance.

    Science.gov (United States)

    Dai, Bing; Wu, Qinxuan; Zeng, Chengxi; Zhang, Jiani; Cao, Luting; Xiao, Zizeng; Yang, Menglin

    2016-11-04

    Liuwei Dihaung decoction (LWDHT) is a well-known classic traditional Chinese medicine formula, consists of six herbs including Rehmannia glutinosa Libosch.(family: Scrophulariaceae), Cornus officinalis Sieb.(family: Cornaceae), Dioscorea opposite Thunb.(family: Dioscoreaceae), Alisma orientale(G. Samuelsson) Juz (family: Alismataceae), Poria cocos (Schw.) Wolf (family: Polyporaceae) and Paeonia suffruticosa Andrews (family: Paeoniaceae). It has been used in the treatment of many types of diseases with signs of deficiency of Yin in the kidneys in China clinically. This study is aimed at investigating the effect of Liuwei dihuang decoction on PI3K/Akt signaling pathway in liver of T2DM rats with insulin resistance. T2DM model was induced in male Sprague-Dawley (SD) rats by high sugar and high fat diets combined with small dose of streptozocin (STZ) injection. The successful T2DM rats were randomly allocated three group--vehicle group, positive control group and Liuwei Dihuang decoction group. After 12-weeks treatment with distilled water, rosiglitazone and LWDHT by intragastric administration respectively, the rats were put to death in batches. The variance of fasting blood glucose (FBG) and fasting insulin (FINS) in serum were determined, the pathological changes of each rats' liver were observed by hematoxylin-eosin (HE) staining, the expression of insulin receptor substrate 2(IRS2), phosphatidylinositol 3-kinase (PI3K) and protein kinas B (Akt) involving the canonical PI3K/Akt signaling pathway were detected by Real-time fluorescent quantitative PCR (RT-PCR), and the expression level of IRS2, PI3K, Akt protein and phosphorylated IRS2, PI3K, Akt protein were evaluated by Western Blot. All the data were analyzed by SPSS 17.0. Four weeks of treatment with LWDHT could significantly decrease the level of FBG and FINS in serum, improve the cellular morphology of liver, kidney, pancreas tissue, and the expression of IRS2, PI3K, Akt mRNA and phosphorylated IRS2, PI3K, Akt

  19. Isolation and cross-sensitivity of X-ray-sensitive mutants of V79-4 hamster cells

    International Nuclear Information System (INIS)

    Jones, N.J.; Cox, R.; Thacker, J.

    1987-01-01

    The V79-4 Chinese hamster line was mutagenized and surviving clones screened for X-ray sensitivity using a replica microwell technique. One slightly sensitive clone and 3 clearly sensitive clones were isolated from approximately 5000 screened, and designated irs 1 to irs 4. The 3 more sensitive clones showed different responses to the genotoxic agents mitomycin C (MMC), ethyl methanesulphonate (EMS) and ultraviolet light (UV). irs 1 showed considerable sensitivity to all the agents tested, in the order MMC >> EMS > UV. irs 2 and irs 3 had similar sensitivities to EMS and to UV (EMS > UV) but irs 3 was more sensitive than irs 2 to MMC. None of these mutants is identical in phenotype to previously published mutants. (Auth.)

  20. Current techniques for the collection and processing of stable isotope data

    International Nuclear Information System (INIS)

    Goodney, D.E.; Kroopnick, P.M.

    1978-01-01

    Recent innovations in instrumentation for stable isotope mass spectrometry are reviewed. 'Off-line' automatic data collection and 'on-line' processing systems have been developed for use with the Nuclide Integrating Ratiometer (IR-2). A BASIC program detects and corrects most instrumental and operator errors and performs all necessary computations. Analysis of the effects of source gas pressure on the accuracy of delta 18 O measurement showed that our Nuclide 3inch-60 0 instrument has a slope of -1.0 0 / 00 /volt over the normal operating range (10-30V), and our Nuclide 6inch-60 0 instrument has a slope of +0.6 0 / 00 /volt. Use of the IR-2 causes the apparent slopes to change to -1.45 0 / 00 /volt and +5 0 / 00 /volt for the 3inch and 6inch instruments, respectively.(auth.)

  1. Atick salivary protein targets cathepsin G and chymase and inhibits host inflammation and platelet aggregation

    Czech Academy of Sciences Publication Activity Database

    Chmelař, Jindřich; Oliveira, C. J.; Řezáčová, Pavlína; Francischetti, I.M.B.; Kovářová, Zuzana; Pejler, G.; Kopáček, Petr; Ribeiro, J.M.C.; Mareš, Michael; Kopecký, Jan; Kotsyfakis, Michalis

    2011-01-01

    Roč. 117, č. 2 (2011), s. 736-744 ISSN 0006-4971 R&D Projects: GA AV ČR IAA600960811; GA MŠk(CZ) LC06009; GA ČR(CZ) GAP207/10/2183 Institutional research plan: CEZ:AV0Z60220518; CEZ:AV0Z40550506 Keywords : parasite serpin * IRS-2 * tick * Ixodes ricinus * platelet aggregation * inflammation * cathepsin G * chymase Subject RIV: EC - Immunology Impact factor: 9.898, year: 2011

  2. Sensitivity of the Yo-Yo Intermittent Recovery Test and cardiac autonomic responses to training in futsal players.

    Science.gov (United States)

    de Freitas, Victor H; Pereira, Lucas A; de Souza, Eberton A; Leicht, Anthony S; Bertollo, Maurizio; Nakamura, Fábio Y

    2015-07-01

    This study examined the sensitivity of maximal (Yo-Yo Intermittent Recovery [IR] 1 and 2) and submaximal (5'-5') tests to identify training adaptations in futsal players along with the suitability of heart-rate (HR) and HR-variability (HRV) measures to identify these adaptations. Eleven male professional futsal players were assessed before (pretraining) and after (posttraining) a 5-wk period. Assessments included 5'-5' and Yo-Yo IR1 and IR2 performances and HR and HRV at rest and during the IR and 5'-5' tests. Magnitude-based-inference analyses examined the differences between pre- and posttraining, while relationships between changes in variables were determined via correlation. Posttraining, Yo-Yo IR1 performance likely increased while Yo-Yo IR2 performance almost certainly increased. Submaximal HR during the Yo-Yo IR1 and Yo-Yo IR2 almost certainly and likely, respectively, decreased with training. HR during the 5'-5' was very likely decreased, while HRV at rest and during the 5'-5' was likely increased after training. Changes in both Yo-Yo IR performances were negatively correlated with changes in HR during the Yo-Yo IR1 test and positively correlated with the change in HRV during the 5'-5'. The current study has identified the Yo-Yo IR2 as more responsive for monitoring training-induced changes of futsal players than the Yo-Yo IR1. Changes in submaximal HR during the Yo-Yo IR and HRV during the 5'-5' were highly sensitive to changes in maximal performance and are recommended for monitoring training. The 5'-5' was recommended as a time-efficient method to assess training adaptations for futsal players.

  3. Electron spin resonance in Yb-based Kondo-lattice systems

    International Nuclear Information System (INIS)

    Wykhoff, Jan

    2010-01-01

    The systems Yb 1-w A 1-w (Rh 1-x Co x )(Si 1-y Ge y ) 2 with A=La respectively Lu, as well as YbIr 2 Si 2 are studied. The measurements are presented sortedly for systems, dopings, and external parameters. Beside these external parameters furthermore the orientation of the sample related to the quasistatic magnetic field and the microwave magnetic field was varied.

  4. 2,3-Diaminophenazine

    Directory of Open Access Journals (Sweden)

    Shiyu Fu

    2011-07-01

    Full Text Available Herein, we synthesized 2,3-diaminophenazine (DAP from o-phenylenediamine (OP using fungal laccase as a biocatalyst. The conversion ratio of OP monomer was 85% and the yield of the final purified product, DAP, was 63%. The structure of the main product, DAP, was confirmed by using several spectroscopy techniques (UV-VIS, IR, 2D-NMR, and MS.

  5. Up-regulation of Kir2.1 by ER stress facilitates cell death of brain capillary endothelial cells

    International Nuclear Information System (INIS)

    Kito, Hiroaki; Yamazaki, Daiju; Ohya, Susumu; Yamamura, Hisao; Asai, Kiyofumi; Imaizumi, Yuji

    2011-01-01

    Highlights: → We found that application of endoplasmic reticulum (ER) stress with tunicamycin to brain capillary endothelial cells (BCECs) induced cell death. → The ER stress facilitated the expression of inward rectifier K + channel (K ir 2.1) and induced sustained membrane hyperpolarization. → The membrane hyperpolarization induced sustained Ca 2+ entry through voltage-independent nonspecific cation channels and consequently facilitated cell death. → The K ir 2.1 up-regulation by ER stress is, at least in part, responsible for cell death of BCECs under pathological conditions. -- Abstract: Brain capillary endothelial cells (BCECs) form blood brain barrier (BBB) to maintain brain homeostasis. Cell turnover of BCECs by the balance of cell proliferation and cell death is critical for maintaining the integrity of BBB. Here we found that stimuli with tunicamycin, endoplasmic reticulum (ER) stress inducer, up-regulated inward rectifier K + channel (K ir 2.1) and facilitated cell death in t-BBEC117, a cell line derived from bovine BCECs. The activation of K ir channels contributed to the establishment of deeply negative resting membrane potential in t-BBEC117. The deep resting membrane potential increased the resting intracellular Ca 2+ concentration due to Ca 2+ influx through non-selective cation channels and thereby partly but significantly regulated cell death in t-BBEC117. The present results suggest that the up-regulation of K ir 2.1 is, at least in part, responsible for cell death/cell turnover of BCECs induced by a variety of cellular stresses, particularly ER stress, under pathological conditions.

  6. Validity and reliability of 6-a-side small-sided game locomotor performance in assessing physical fitness in football players.

    Science.gov (United States)

    Stevens, Tom Gerardus Antonia; De Ruiter, Cornelis Johannes; Beek, Peter Jan; Savelsbergh, Geert Jozef Peter

    2016-01-01

    In order to determine whether small-sided game (SSG) locomotor performance can serve as a fitness indicator, we (1) compared 6-a-side (6v6) SSG-intensity of players varying in fitness and skill, (2) examined the relationship of the 6v6-SSG and Yo-Yo IR2 and (3) assessed the reliability of the 6v6-SSG. Thirty-three professional senior, 30 professional youth, 62 amateur and 16 professional woman football players performed 4 × 7 min 6v6-SSGs recorded by a Local Position Measurement system. A substantial subgroup (N = 113) also performed the Yo-Yo IR2. Forty-seven amateur players performed two or three 6v6-SSGs. No differences in 6v6-SSG time-motion variables were found between professional senior and professional youth players. Amateurs showed lower values than professional seniors on almost all time-motion variables (ES = 0.59-1.19). Women displayed lower high-intensity time-motion variables than all other subgroups. Total distance run during 6v6-SSG was only moderately related to Yo-Yo IR2 distance (r = 0.45), but estimated metabolic power, high speed (>14.4 km · h(-1)), high acceleration (>2 m · s(-2)), high power (>20 W · kg(-1)) and very high (35 W · kg(-1)) power showed higher correlations (r = 0.59-0.70) with Yo-Yo IR2 distance. Intraclass correlation coefficient values were higher for total distance (0.84) than other time-motion variables (0.74‒0.78). Although total distance and metabolic power during 6v6-SSG showed good reproducibility (coefficient of variation (CV) < 5%), CV was higher (8-14%) for all high-intensity time-motion variables. It was therefore concluded that standardised SSG locomotor performance cannot serve used as a valid and reliable fitness indicator for individual players.

  7. Water Leakage and Nitrate Leaching Characteristics in the Winter Wheat–Summer Maize Rotation System in the North China Plain under Different Irrigation and Fertilization Management Practices

    Directory of Open Access Journals (Sweden)

    Shufeng Chen

    2017-02-01

    Full Text Available Field experiments were carried out in Huantai County from 2006 to 2008 to evaluate the effects of different nitrogen (N fertilization and irrigation management practices on water leakage and nitrate leaching in the dominant wheat–maize rotation system in the North China Plain (NCP. Two N fertilization (NF1, the traditional one; NF2, fertilization based on soil testing and two irrigation (IR1, the traditional one; IR2, irrigation based on real-time soil water content monitoring management practices were designed in the experiments. Water and nitrate amounts leaving the soil layer at a depth of 2.0 m below the soil surface were calculated and compared. Results showed that the IR2 effectively reduced water leakage and nitrate leaching amounts in the two-year period, especially in the winter wheat season. Less than 10 percent irrigation water could be saved in a dry winter wheat season, but about 60 percent could be saved in a wet winter wheat season. Besides, 58.8 percent nitrate under single NF2IR1 and 85.2 percent under NF2IR2 could be prevented from leaching. The IR2 should be considered as the best management practice to save groundwater resources and prevent nitrate from leaching. The amounts of N input play a great role in affecting nitrate concentrations in the soil solutions in the winter wheat–summer maize rotation system. The NF2 significantly reduced N inputs and should be encouraged in ordinary agricultural production. Thus, nitrate leaching and groundwater contamination could be alleviated, but timely N supplement might be needed under high precipitation condition.

  8. Di-μ-chlorido-bis[bis(η2-cycloocteneiridium(I

    Directory of Open Access Journals (Sweden)

    Kazuhide Tani

    2008-04-01

    Full Text Available The title complex, [Ir2(μ-Cl2(C8H144], has a dinuclear structure with bridging Cl atoms, a hinge angle of 179.44 (7° between the two IrCl2 planes, and an Ir...Ir distance of 3.7254 (3 Å. Regarding the coordinating C=C bonds as occupying a single coordination site each, the geometry around each Ir atom is square-planar.

  9. Chronic Alcohol Consumption Alters Mammalian Target of Rapamycin (mTOR), Reduces Ribosomal p70S6 Kinase and p4E-BP1 Levels in Mouse Cerebral Cortex

    OpenAIRE

    Li, Qun; Ren, Jun

    2007-01-01

    Reduced insulin sensitivity following chronic alcohol consumption may contribute to alcohol-induced brain damage although the underlying mechanism(s) has not been elucidated. This study was designed to examine the effect of chronic alcohol intake on insulin signaling in mouse cerebral cortex. FVB mice were fed with a 4% alcohol diet for 16 weeks. Insulin receptor substrates (IRS-1, IRS-2) and post-receptor signaling molecules Akt, mammalian target of rapamycin (mTOR), ribosomal p70s6 kinase (...

  10. Finite element approximation to a model problem of transonic flow

    International Nuclear Information System (INIS)

    Tangmanee, S.

    1986-12-01

    A model problem of transonic flow ''the Tricomi equation'' in Ω is contained in IR 2 bounded by the rectangular-curve boundary is posed in the form of symmetric positive differential equations. The finite element method is then applied. When the triangulation of Ω-bar is made of quadrilaterals and the approximation space is the Lagrange polynomial, we get the error estimates. 14 refs, 1 fig

  11. Selective Insulin Resistance in the Kidney

    Science.gov (United States)

    Horita, Shoko; Nakamura, Motonobu; Suzuki, Masashi; Satoh, Nobuhiko; Suzuki, Atsushi; Seki, George

    2016-01-01

    Insulin resistance has been characterized as attenuation of insulin sensitivity at target organs and tissues, such as muscle and fat tissues and the liver. The insulin signaling cascade is divided into major pathways such as the PI3K/Akt pathway and the MAPK/MEK pathway. In insulin resistance, however, these pathways are not equally impaired. For example, in the liver, inhibition of gluconeogenesis by the insulin receptor substrate (IRS) 2 pathway is impaired, while lipogenesis by the IRS1 pathway is preserved, thus causing hyperglycemia and hyperlipidemia. It has been recently suggested that selective impairment of insulin signaling cascades in insulin resistance also occurs in the kidney. In the renal proximal tubule, insulin signaling via IRS1 is inhibited, while insulin signaling via IRS2 is preserved. Insulin signaling via IRS2 continues to stimulate sodium reabsorption in the proximal tubule and causes sodium retention, edema, and hypertension. IRS1 signaling deficiency in the proximal tubule may impair IRS1-mediated inhibition of gluconeogenesis, which could induce hyperglycemia by preserving glucose production. In the glomerulus, the impairment of IRS1 signaling deteriorates the structure and function of podocyte and endothelial cells, possibly causing diabetic nephropathy. This paper mainly describes selective insulin resistance in the kidney, focusing on the proximal tubule. PMID:27247938

  12. Quantum phase transitions and anomalous Hall effect in a pyrochlore Kondo lattice

    Science.gov (United States)

    Grefe, Sarah; Ding, Wenxin; Si, Qimiao

    The metallic variant of the pyrochlore iridates Pr2Ir2O7 has shown characteristics of a possible chiral spin liquid state [PRL 96 087204 (2006), PRL 98, 057203 (2007), Nature 463, 210 (2010)] and quantum criticality [Nat. Mater. 13, 356 (2014)]. An important question surrounding the significant anomalous Hall response observed in Pr2Ir2O7 is the nature of the f-electron local moments, including their Kondo coupling with the conduction d-electrons. The heavy effective mass and related thermodynamic characteristics indicate the involvement of the Kondo effect in this system's electronic properties. In this work, we study the effects of Kondo coupling on candidate time-reversal-symmetry-breaking spin liquid states on the pyrochlore lattice. Representing the f-moments as slave fermions Kondo-coupled to conduction electrons, we study the competition between Kondo-singlet formation and chiral spin correlations and determine the zero-temperature phase diagram. We derive an effective chiral interaction between the local moments and the conduction electrons and calculate the anomalous Hall response across the quantum phase transition from the Kondo destroyed phase to the Kondo screened phase. We discuss our results' implications for Pr2Ir2O7 and related frustrated Kondo-lattice systems.

  13. Moderate running and plyometric training during off-season did not show a significant difference on soccer-related high-intensity performances compared with no-training controls.

    Science.gov (United States)

    Nakamura, Daisuke; Suzuki, Tomohiro; Yasumatsu, Mikinobu; Akimoto, Takayuki

    2012-12-01

    Several investigators have reported the effects of reduced training and interrupted training on athletic performance, but few reports are available for soccer players. The purpose of this study was to examine, using the Yo-Yo intermittent recovery level 2 (YoYoIR2) test and sprint performance, the effects on soccer players of a reduced training program consisting of either moderate running training, plyometric training. After the completion of a competitive season, 29 male soccer players were divided into 3 groups: the running group (n = 13), the plyometric group (n = 11), and the control group (n = 5). Both training groups completed either running or plyometric training sessions 2 d·wk(-1) for 3 weeks, whereas the control group was not allowed to perform any training. The subjects performed YoYoIR2 and 20-m sprint tests before (pre) and after (post) the experimental period. Neither training group showed any significant training effects on the YoYoIR2 performance or 20-m sprint times compared with the control group. This study suggests that neither endurance running nor plyometric training 2 d·wk(-1) for 3 weeks has a significant effect on high-intensity performance compared with a nontraining regimen. However, our results do not support complete inactivity. These results may have important implications for the management of training cessation for a few weeks.

  14. Dimethylaminoparthenolide and gemcitabine: a survival study using a genetically engineered mouse model of pancreatic cancer

    International Nuclear Information System (INIS)

    Yip-Schneider, Michele T; Wu, Huangbing; Stantz, Keith; Agaram, Narasimhan; Crooks, Peter A; Schmidt, C Max

    2013-01-01

    Pancreatic cancer remains one of the deadliest cancers due to lack of early detection and absence of effective treatments. Gemcitabine, the current standard-of-care chemotherapy for pancreatic cancer, has limited clinical benefit. Treatment of pancreatic cancer cells with gemcitabine has been shown to induce the activity of the transcription factor nuclear factor-kappaB (NF-κB) which regulates the expression of genes involved in the inflammatory response and tumorigenesis. It has therefore been proposed that gemcitabine-induced NF-κB activation may result in chemoresistance. We hypothesize that NF-κB suppression by the novel inhibitor dimethylaminoparthenolide (DMAPT) may enhance the effect of gemcitabine in pancreatic cancer. The efficacy of DMAPT and gemcitabine was evaluated in a chemoprevention trial using the mutant Kras and p53-expressing LSL-Kras G12D/+ ; LSL-Trp53 R172H ; Pdx-1-Cre mouse model of pancreatic cancer. Mice were randomized to treatment groups (placebo, DMAPT [40 mg/kg/day], gemcitabine [50 mg/kg twice weekly], and the combination DMAPT/gemcitabine). Treatment was continued until mice showed signs of ill health at which time they were sacrificed. Plasma cytokine levels were determined using a Bio-Plex immunoassay. Statistical tests used included log-rank test, ANOVA with Dunnett’s post-test, Student’s t-test, and Fisher exact test. Gemcitabine or the combination DMAPT/gemcitabine significantly increased median survival and decreased the incidence and multiplicity of pancreatic adenocarcinomas. The DMAPT/gemcitabine combination also significantly decreased tumor size and the incidence of metastasis to the liver. No significant differences in the percentages of normal pancreatic ducts or premalignant pancreatic lesions were observed between the treatment groups. Pancreata in which no tumors formed were analyzed to determine the extent of pre-neoplasia; mostly normal ducts or low grade pancreatic lesions were observed, suggesting prevention

  15. Mapping Mammalian Cell-type-specific Transcriptional Regulatory Networks Using KD-CAGE and ChIP-seq Data in the TC-YIK Cell Line

    Science.gov (United States)

    Lizio, Marina; Ishizu, Yuri; Itoh, Masayoshi; Lassmann, Timo; Hasegawa, Akira; Kubosaki, Atsutaka; Severin, Jessica; Kawaji, Hideya; Nakamura, Yukio; Suzuki, Harukazu; Hayashizaki, Yoshihide; Carninci, Piero; Forrest, Alistair R. R.

    2015-01-01

    Mammals are composed of hundreds of different cell types with specialized functions. Each of these cellular phenotypes are controlled by different combinations of transcription factors. Using a human non islet cell insulinoma cell line (TC-YIK) which expresses insulin and the majority of known pancreatic beta cell specific genes as an example, we describe a general approach to identify key cell-type-specific transcription factors (TFs) and their direct and indirect targets. By ranking all human TFs by their level of enriched expression in TC-YIK relative to a broad collection of samples (FANTOM5), we confirmed known key regulators of pancreatic function and development. Systematic siRNA mediated perturbation of these TFs followed by qRT-PCR revealed their interconnections with NEUROD1 at the top of the regulation hierarchy and its depletion drastically reducing insulin levels. For 15 of the TF knock-downs (KD), we then used Cap Analysis of Gene Expression (CAGE) to identify thousands of their targets genome-wide (KD-CAGE). The data confirm NEUROD1 as a key positive regulator in the transcriptional regulatory network (TRN), and ISL1, and PROX1 as antagonists. As a complimentary approach we used ChIP-seq on four of these factors to identify NEUROD1, LMX1A, PAX6, and RFX6 binding sites in the human genome. Examining the overlap between genes perturbed in the KD-CAGE experiments and genes with a ChIP-seq peak within 50 kb of their promoter, we identified direct transcriptional targets of these TFs. Integration of KD-CAGE and ChIP-seq data shows that both NEUROD1 and LMX1A work as the main transcriptional activators. In the core TRN (i.e., TF-TF only), NEUROD1 directly transcriptionally activates the pancreatic TFs HSF4, INSM1, MLXIPL, MYT1, NKX6-3, ONECUT2, PAX4, PROX1, RFX6, ST18, DACH1, and SHOX2, while LMX1A directly transcriptionally activates DACH1, SHOX2, PAX6, and PDX1. Analysis of these complementary datasets suggests the need for caution in interpreting Ch

  16. Role of nutrients and mTOR signaling in the regulation of pancreatic progenitors development

    Directory of Open Access Journals (Sweden)

    Lynda Elghazi

    2017-06-01

    Full Text Available Objective: Poor fetal nutrition increases the risk of type 2 diabetes in the offspring at least in part by reduced embryonic β-cell growth and impaired function. However, it is not entirely clear how fetal nutrients and growth factors impact β-cells during development to alter glucose homeostasis and metabolism later in life. The current experiments aimed to test the impact of fetal nutrients and growth factors on endocrine development and how these signals acting on mTOR signaling regulate β-cell mass and glucose homeostasis. Method: Pancreatic rudiments in culture were used to study the role of glucose, growth factors, and amino acids on β-cell development. The number and proliferation of pancreatic and endocrine progenitor were assessed in the presence or absence of rapamycin. The impact of mTOR signaling in vivo on pancreas development and glucose homeostasis was assessed in models deficient for mTOR or Raptor in Pdx1 expressing pancreatic progenitors. Results: We found that amino acid concentrations, and leucine in particular, enhance the number of pancreatic and endocrine progenitors and are essential for growth factor induced proliferation. Rapamycin, an mTORC1 complex inhibitor, reduced the number and proliferation of pancreatic and endocrine progenitors. Mice lacking mTOR in pancreatic progenitors exhibited hyperglycemia in neonates, hypoinsulinemia and pancreatic agenesis/hypoplasia with pancreas rudiments containing ductal structures lacking differentiated acinar and endocrine cells. In addition, loss of mTORC1 by deletion of raptor in pancreatic progenitors reduced pancreas size with reduced number of β-cells. Conclusion: Together, these results suggest that amino acids concentrations and in particular leucine modulates growth responses of pancreatic and endocrine progenitors and that mTOR signaling is critical for these responses. Inactivation of mTOR and raptor in pancreatic progenitors suggested that alterations in some of

  17. Sustained expression of GLP-1 receptor differentially modulates β-cell functions in diabetic and nondiabetic mice

    International Nuclear Information System (INIS)

    Kubo, Fumiyo; Miyatsuka, Takeshi; Sasaki, Shugo; Takahara, Mitsuyoshi; Yamamoto, Yuichi; Shimo, Naoki; Watada, Hirotaka; Kaneto, Hideaki; Gannon, Maureen; Matsuoka, Taka-aki; Shimomura, Iichiro

    2016-01-01

    Glucagon-like peptide 1 (GLP-1) has been shown to play important roles in maintaining β-cell functions, such as insulin secretion and proliferation. While expression levels of GLP-1 receptor (Glp1r) are compromised in the islets of diabetic rodents, it remains unclear when and to what degree Glp1r mRNA levels are decreased during the progression of diabetes. In this study, we performed real-time PCR with the islets of db/db diabetic mice at different ages, and found that the expression levels of Glp1r were comparable to those of the islets of nondiabetic db/misty controls at the age of four weeks, and were significantly decreased at the age of eight and 12 weeks. To investigate whether restored expression of Glp1r affects the diabetic phenotypes, we generated the transgenic mouse model Pdx1"P"B-CreER"T"M; CAG-CAT-Glp1r (βGlp1r) that allows for induction of Glp1r expression specifically in β cells. Whereas the expression of exogenous Glp1r had no measurable effect on glucose tolerance in nondiabetic βGlp1r;db/misty mice, βGlp1r;db/db mice exhibited higher glucose and lower insulin levels in blood on glucose challenge test than control db/db littermates. In contrast, four weeks of treatment with exendin-4 improved the glucose profiles and increased serum insulin levels in βGlp1r;db/db mice, to significantly higher levels than those in control db/db mice. These differential effects of exogenous Glp1r in nondiabetic and diabetic mice suggest that downregulation of Glp1r might be required to slow the progression of β-cell failure under diabetic conditions. - Highlights: • Expression levels of incretin receptors were significantly decreased in diabetic db/db islets after the age of eight weeks. • A transgenic mouse model expressing Glp1r specifically in β cells was generated. • Exogenous expression of Glp1r in β cells did not affect metabolic profiles in nondiabetic mice. • Sustained expression of Glp1r in diabetic db/db β cells deteriorated glucose

  18. Sustained expression of GLP-1 receptor differentially modulates β-cell functions in diabetic and nondiabetic mice

    Energy Technology Data Exchange (ETDEWEB)

    Kubo, Fumiyo [Department of Metabolic Medicine, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka 565-0871 (Japan); Miyatsuka, Takeshi, E-mail: miyatsuka-takeshi@umin.net [Department of Metabolic Medicine, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka 565-0871 (Japan); Department of Medicine, Metabolism and Endocrinology, Juntendo University Graduate School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo 113-8421 (Japan); Sasaki, Shugo; Takahara, Mitsuyoshi; Yamamoto, Yuichi; Shimo, Naoki [Department of Metabolic Medicine, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka 565-0871 (Japan); Watada, Hirotaka [Department of Medicine, Metabolism and Endocrinology, Juntendo University Graduate School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo 113-8421 (Japan); Kaneto, Hideaki [Department of Diabetes, Endocrinology and Metabolism, Kawasaki Medical School, 577 Matsushima, Kurashiki, Japan Okayama 701-0192 (Japan); Gannon, Maureen [Department of Medicine, Division of Diabetes, Endocrinology, and Metabolism, Vanderbilt University Medical Center, 2220 Pierce Ave. 746 PRB, Nashville, TN 37232-6303 (United States); Matsuoka, Taka-aki; Shimomura, Iichiro [Department of Metabolic Medicine, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka 565-0871 (Japan)

    2016-02-26

    Glucagon-like peptide 1 (GLP-1) has been shown to play important roles in maintaining β-cell functions, such as insulin secretion and proliferation. While expression levels of GLP-1 receptor (Glp1r) are compromised in the islets of diabetic rodents, it remains unclear when and to what degree Glp1r mRNA levels are decreased during the progression of diabetes. In this study, we performed real-time PCR with the islets of db/db diabetic mice at different ages, and found that the expression levels of Glp1r were comparable to those of the islets of nondiabetic db/misty controls at the age of four weeks, and were significantly decreased at the age of eight and 12 weeks. To investigate whether restored expression of Glp1r affects the diabetic phenotypes, we generated the transgenic mouse model Pdx1{sup PB}-CreER{sup TM}; CAG-CAT-Glp1r (βGlp1r) that allows for induction of Glp1r expression specifically in β cells. Whereas the expression of exogenous Glp1r had no measurable effect on glucose tolerance in nondiabetic βGlp1r;db/misty mice, βGlp1r;db/db mice exhibited higher glucose and lower insulin levels in blood on glucose challenge test than control db/db littermates. In contrast, four weeks of treatment with exendin-4 improved the glucose profiles and increased serum insulin levels in βGlp1r;db/db mice, to significantly higher levels than those in control db/db mice. These differential effects of exogenous Glp1r in nondiabetic and diabetic mice suggest that downregulation of Glp1r might be required to slow the progression of β-cell failure under diabetic conditions. - Highlights: • Expression levels of incretin receptors were significantly decreased in diabetic db/db islets after the age of eight weeks. • A transgenic mouse model expressing Glp1r specifically in β cells was generated. • Exogenous expression of Glp1r in β cells did not affect metabolic profiles in nondiabetic mice. • Sustained expression of Glp1r in diabetic db/db β cells deteriorated

  19. A high-fat diet activates oncogenic Kras and COX2 to induce development of pancreatic ductal adenocarcinoma in mice.

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    Philip, Bincy; Roland, Christina L; Daniluk, Jaroslaw; Liu, Yan; Chatterjee, Deyali; Gomez, Sobeyda B; Ji, Baoan; Huang, Haojie; Wang, Huamin; Fleming, Jason B; Logsdon, Craig D; Cruz-Monserrate, Zobeida

    2013-12-01

    Obesity is a risk factor for pancreatic ductal adenocarcinoma (PDAC), but it is not clear how obesity contributes to pancreatic carcinogenesis. The oncogenic form of KRAS is expressed during early stages of PDAC development and is detected in almost all of these tumors. However, there is evidence that mutant KRAS requires an additional stimulus to activate its full oncogenic activity and that this stimulus involves the inflammatory response. We investigated whether the inflammation induced by a high-fat diet, and the accompanying up-regulation of cyclooxygenase-2 (COX2), increases Kras activity during pancreatic carcinogenesis in mice. We studied mice with acinar cell-specific expression of KrasG12D (LSL-Kras/Ela-CreERT mice) alone or crossed with COX2 conditional knockout mice (COXKO/LSL-Kras/Ela-CreERT). We also studied LSL-Kras/PDX1-Cre mice. All mice were fed isocaloric diets with different amounts of fat, and a COX2 inhibitor was administered to some LSL-Kras/Ela-CreERT mice. Pancreata were collected from mice and analyzed for Kras activity, levels of phosphorylated extracellular-regulated kinase, inflammation, fibrosis, pancreatic intraepithelial neoplasia (PanIN), and PDACs. Pancreatic tissues from LSL-Kras/Ela-CreERT mice fed high-fat diets (HFDs) had increased Kras activity, fibrotic stroma, and numbers of PanINs and PDACs than LSL-Kras/Ela-CreERT mice fed control diets; the mice fed the HFDs also had shorter survival times than mice fed control diets. Administration of a COX2 inhibitor to LSL-Kras/Ela-CreERT mice prevented these effects of HFDs. We also observed a significant reduction in survival times of mice fed HFDs. COXKO/LSL-Kras/Ela-CreERT mice fed HFDs had no evidence for increased numbers of PanIN lesions, inflammation, or fibrosis, as opposed to the increases observed in LSL-Kras/Ela-CreERT mice fed HFDs. In mice, an HFD can activate oncogenic Kras via COX2, leading to pancreatic inflammation and fibrosis and development of PanINs and PDAC. This

  20. Iterative use of nuclear receptor Nr5a2 regulates multiple stages of liver and pancreas development

    Science.gov (United States)

    Nissim, Sahar; Weeks, Olivia; Talbot, Jared C.; Hedgepeth, John W.; Wucherpfennig, Julia; Schatzman-Bone, Stephanie; Swinburne, Ian; Cortes, Mauricio; Alexa, Kristen; Megason, Sean; North, Trista E.; Amacher, Sharon L.; Goessling, Wolfram

    2016-01-01

    The stepwise progression of common endoderm progenitors into differentiated liver and pancreas organs is regulated by a dynamic array of signals that are not well understood. The nuclear receptor subfamily 5, group A, member 2 gene nr5a2, also known as Liver receptor homolog-1 (Lrh-1) is expressed in several tissues including the developing liver and pancreas. Here, we interrogate the role of Nr5a2 at multiple developmental stages using genetic and chemical approaches and uncover novel pleiotropic requirements during zebrafish liver and pancreas development. Zygotic loss of nr5a2 in a targeted genetic null mutant disrupted the development of the exocrine pancreas and liver, while leaving the endocrine pancreas intact. Loss of nr5a2 abrogated exocrine pancreas markers such as trypsin, while pancreas progenitors marked by ptf1a or pdx1 remained unaffected, suggesting a role for Nr5a2 in regulating pancreatic acinar cell differentiation. In the developing liver, Nr5a2 regulates hepatic progenitor outgrowth and differentiation, as nr5a2 mutants exhibited reduced hepatoblast markers hnf4α and prox1 as well as differentiated hepatocyte marker fabp10a. Through the first in vivo use of Nr5a2 chemical antagonist Cpd3, the iterative requirement for Nr5a2 for exocrine pancreas and liver differentiation was temporally elucidated: chemical inhibition of Nr5a2 function during hepatopancreas progenitor specification was sufficient to disrupt exocrine pancreas formation and enhance the size of the embryonic liver, suggesting that Nr5a2 regulates hepatic versus pancreatic progenitor fate choice. Chemical inhibition of Nr5a2 at a later time during pancreas and liver differentiation was sufficient to block the formation of mature acinar cells and hepatocytes. These findings define critical iterative and pleiotropic roles for Nr5a2 at distinct stages of pancreas and liver organogenesis, and provide novel perspectives for interpreting the role of Nr5a2 in disease. PMID:27474396

  1. Progenitor potential of nkx6.1-expressing cells throughout zebrafish life and during beta cell regeneration.

    Science.gov (United States)

    Ghaye, Aurélie P; Bergemann, David; Tarifeño-Saldivia, Estefania; Flasse, Lydie C; Von Berg, Virginie; Peers, Bernard; Voz, Marianne L; Manfroid, Isabelle

    2015-09-02

    contrast to the mouse, pancreatic progenitor markers nkx6.1 and pdx1 continue to be expressed in adult ductal cells, a subset of which we show are still able to proliferate and undergo ductal and endocrine differentiation, providing robust evidence of the existence of pancreatic progenitor/stem cells in the adult zebrafish. Our findings support the hypothesis that nkx6.1+ pancreatic progenitors contribute to beta cell regeneration. Further characterization of these cells will open up new perspectives for anti-diabetic therapies.

  2. The role of gut-liver axis in the restriction of intrauterine growth in a model of experimental gastroschisis O papel do eixo intestino-fígado na restrição de crescimento intra-uterino em um modelo de gastrosquise experimental

    Directory of Open Access Journals (Sweden)

    Márcia Pereira Bueno

    2013-01-01

    Full Text Available PURPOSE: To evaluate the intrauterine growth restriction (IUGR by the expression of IR-β, IRS-1, IRS-2, IGF-IRβ and Ikappaβ in experimental model of gastroschisis. METHODS: Pregnant rats at 18.5 days of gestation were submitted to surgery to create experimental fetal gastroschisis (term = 22 days were divided in three groups: gastroschisis (G, control (C and sham (S. Fetuses were evaluated for body weight (BW, intestinal (IW, liver (LW and their relations IW/BW and LW/BW. IR-β and IGF-IRβ receptors, IRS-1 and IRS-2 substrates and Ikappaβ protein were analyzed by western blotting. RESULTS: BW was lower in G, the IW and IW / BW were greater than C and S (pOBJETIVO: Avaliar a restrição de crescimento intra-uterino (RCIU pela expressão de IR-β, IRS-1, IRS-2, IGF-IRβ e a via inflamatória do Ikappaβ no modelo de gastrosquise experimental. MÉTODOS: Ratas grávidas com 18,5 dias de gestação foram submetidas a cirurgia experimental para criar gastrosquise fetal (termo = 22 dias e os fetos foram divididos em três grupos: gastrosquise (G, controle (C e sham (S. Os fetos foram avaliados quanto ao peso corporal (BW, intestinal (IW, fígado (LW e suas relações IW/BW e LW/BW. Os receptores IR-β e IGF-IRβ, os substratos IRS-1 e IRS-2 e a proteína Ikappaβ foram analisados por western blotting. RESULTADOS: O BW de G foi menor, o IW e IW/BW foram superiores a C e S (p < 0.05. O fígado não apresentou diferenças entre os grupos. Nos fetos com gastrosquise, quando comparados com fetos controles, a expressão de IGF-IRβ (p<0.001 e Ikappaβ (p<0.001 aumentou no fígado e intestino, assim como IR-β (p<0.001 que diminuiu em ambos. Inversamente ao intestino, IRS-1 (p<0.001 aumentou no fígado e IRS-2 diminuiu (p<0.01. CONCLUSÃO: O eixo do intestino fígado tem um papel importante na inflamação, com consequentes alterações na via metabólica de glicose que pode contribuir para a RCIU em fetos com gastrosquise.

  3. Jinlida reduces insulin resistance and ameliorates liver oxidative stress in high-fat fed rats.

    Science.gov (United States)

    Liu, Yixuan; Song, An; Zang, Shasha; Wang, Chao; Song, Guangyao; Li, Xiaoling; Zhu, Yajun; Yu, Xian; Li, Ling; Wang, Yun; Duan, Liyuan

    2015-03-13

    Jinlida (JLD) is a compound preparation formulated on the basis of traditional Chinese medicine and is officially approved for the treatment of type 2 diabetes (T2DM) in China. We aimed to elucidate the mechanism of JLD treatment, in comparison to metformin treatment, on ameliorating insulin sensitivity in insulin resistant rats and to reveal its anti-oxidant properties. Rats were fed with standard or high-fat diet for 6 weeks. After 6 weeks, the high-fat fed rats were subdivided into five groups and orally fed with JLD or metformin for 8 weeks. Fasting blood glucose (FBG), fasting blood insulin, blood lipid and antioxidant enzymes were measured. Intraperitoneal glucose tolerance test (IPGTT) and hyperinsulinemic euglycemic clamp technique were carried out to measure insulin sensitivity. Gene expression of the major signaling pathway molecules that regulate glucose uptake, including insulin receptor (INSR), insulin receptor substrate-1 (IRS-1), phosphoinositide-3-kinase (PI3K), protein kinase beta (AKT), and glucose transporter type 2 (GLUT2), were assessed by quantitative RT-PCR. The totle and phosphorylation expression of IRS-1, AKT, JNK and p38MAPK were determined by Western blot. Treatment with JLD effectively ameliorated the high-fat induced hyperglycemia, hyperinsulinemia and hyperlipidemia. Similar to metformin, the high insulin resistance in high-fat fed rats was significantly decreased by JLD treatment. JLD displayed anti-oxidant effects, coupled with up-regulation of the insulin signaling pathway. The attenuation of hepatic oxidative stress by JLD treatment was associated with reduced phosphorylation protein levels of JNK and p38MAPK. Treatment with JLD could moderate glucose and lipid metabolism as well as reduce hepatic oxidative stress, most likely through the JNK and p38MAPK pathways. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  4. The projection and synaptic organisation of NTS afferent connections with presympathetic neurons, GABA and nNOS neurons in the paraventricular nucleus of the hypothalamus

    Science.gov (United States)

    Affleck, V.S.; Coote, J.H.; Pyner, S.

    2012-01-01

    Elevated sympathetic nerve activity, strongly associated with cardiovascular disease, is partly generated from the presympathetic neurons of the paraventricular nucleus of the hypothalamus (PVN). The PVN-presympathetic neurons regulating cardiac and vasomotor sympathetic activity receive information about cardiovascular status from receptors in the heart and circulation. These receptors signal changes via afferent neurons terminating in the nucleus tractus solitarius (NTS), some of which may result in excitation or inhibition of PVN-presympathetic neurons. Understanding the anatomy and neurochemistry of NTS afferent connections within the PVN could provide important clues to the impairment in homeostasis cardiovascular control associated with disease. Transynaptic labelling has shown the presence of neuronal nitric oxide synthase (nNOS)-containing neurons and GABA interneurons that terminate on presympathetic PVN neurons any of which may be the target for NTS afferents. So far NTS connections to these diverse neuronal pools have not been demonstrated and were investigated in this study. Anterograde (biotin dextran amine – BDA) labelling of the ascending projection from the NTS and retrograde (fluorogold – FG or cholera toxin B subunit – CTB) labelling of PVN presympathetic neurons combined with immunohistochemistry for GABA and nNOS was used to identify the terminal neuronal targets of the ascending projection from the NTS. It was shown that NTS afferent terminals are apposed to either PVN-GABA interneurons or to nitric oxide producing neurons or even directly to presympathetic neurons. Furthermore, there was evidence that some NTS axons were positive for vesicular glutamate transporter 2 (vGLUT2). The data provide an anatomical basis for the different functions of cardiovascular receptors that mediate their actions via the NTS–PVN pathways. PMID:22698695

  5. Vitamin C and E chronic supplementation differentially affect hepatic insulin signaling in rats.

    Science.gov (United States)

    Ali, Mennatallah A; Eid, Rania M H M; Hanafi, Mervat Y

    2018-02-01

    Vitamin C and vitamin E supplementations and their beneficial effects on type 2 diabetes mellitus (T2DM) have been subjected to countless controversial data. Hence, our aim is to investigate the hepatic molecular mechanisms of any diabetic predisposing risk of the chronic administration of different doses of vitamin E or vitamin C in rats. The rats were supplemented with different doses of vitamin C or vitamin E for eight months. Vitamin C and vitamin E increased fasting blood glucose, insulin, and homeostasis model assessment index for insulin resistance (HOMA). Vitamin C disrupted glucose tolerance by attenuating upstream hepatic insulin action through impairing the phosphorylation and activation of insulin receptor and its subsequent substrates; however, vitamin E showed its effect downstream insulin receptor in the insulin signaling pathway, reducing hepatic glucose transporter-2 (GLUT2) and phosphorylated protein kinase (p-Akt). Moreover, both vitamins showed their antioxidant capabilities [nuclear factor-erythroid-2-related factor 2 (Nrf2), total and reduced glutathione] and their negative effect on Wnt pathway [phosphorylated glycogen synthase kinase-3β (p-GSK-3β)], by altering the previously mentioned parameters, inevitably leading to severe reduction of reactive oxygen species (ROS) below the physiological levels. In conclusion, a detrimental effect of chronic antioxidant vitamins supplementation was detected; leading to insulin resistance and impaired glucose tolerance obviously through different mechanisms. Overall, these findings indicate that the conventional view that vitamins promote health benefits and delay chronic illnesses and aging should be modified or applied with caution. Copyright © 2017. Published by Elsevier Inc.

  6. Nutrient-intake-level-dependent regulation of intestinal development in newborn intrauterine growth-restricted piglets via glucagon-like peptide-2.

    Science.gov (United States)

    Liu, J; Liu, Z; Gao, L; Chen, L; Zhang, H

    2016-10-01

    The objective of the present study was to investigate the intestinal development of newborn intrauterine growth-restricted (IUGR) piglets subjected to normal nutrient intake (NNI) or restricted nutrient intake (RNI). Newborn normal birth weight (NBW) and IUGR piglets were allotted to NNI or RNI levels for 4 weeks from day 8 postnatal. IUGR piglets receiving NNI had similar growth performance compared with that of NBW piglets. Small intestine length and villous height were greater in IUGR piglets fed the NNI than that of piglets fed the RNI. Lactase activity was increased in piglets fed the NNI compared with piglets fed the RNI. Absorptive function, represented by active glucose transport by the Ussing chamber method and messenger RNA (mRNA) expressions of two main intestinal glucose transporters, Na+-dependent glucose transporter 1 (SGLT1) and glucose transporter 2 (GLUT2), were greater in IUGR piglets fed the NNI compared with piglets fed the RNI regimen. The apoptotic process, characterized by caspase-3 activity (a sign of activated apoptotic cells) and mRNA expressions of p53 (pro-apoptotic), bcl-2-like protein 4 (Bax) (pro-apoptotic) and B-cell lymphoma-2 (Bcl-2) (anti-apoptotic), were improved in IUGR piglets fed the NNI regimen. To test the hypothesis that improvements in intestinal development of IUGR piglets fed NNI might be mediated through circulating glucagon-like peptide-2 (GLP-2), GLP-2 was injected subcutaneously to IUGR piglets fed the RNI from day 8 to day 15 postnatal. Although the intestinal development of IUGR piglets fed the RNI regimen was suppressed compared with those fed the NNI regimen, an exogenous injection of GLP-2 was able to bring intestinal development to similar levels as NNI-fed IUGR piglets. Collectively, our results demonstrate that IUGR neonates that have NNI levels could improve intestinal function via the regulation of GLP-2.

  7. Increased insulin sensitivity and changes in the expression profile of key insulin regulatory genes and beta cell transcription factors in diabetic KKAy-mice after feeding with a soy bean protein rich diet high in isoflavone content.

    Science.gov (United States)

    Nordentoft, I; Jeppesen, P B; Hong, J; Abudula, R; Hermansen, K

    2008-06-25

    High content isoflavone soy protein (SBP) (Abalon) has been found in animal studies to possess beneficial effects on a number of the characteristic features of the insulin resistance syndrome. The aim of this study was to investigate whether SBP exerts beneficial effects on metabolism in the diabetic KKAy-mouse. Furthermore, we investigated the long-term in vivo effect of SBP on the expression profile in islets of key insulin regulatory genes. Twenty KKAy-mice, aged 5 weeks, were divided into 2 groups and treated for 9 weeks with either (A) standard chow diet (control) or (B) chow + 50% SBP. Twenty normal C57BL-mice fed with standard chow diet served as nondiabetic controls (C). Blood samples were collected and analyzed before and after intervention. Gene expression was determined in islets by quantitative real-time RT-PCR and Affymetrix microarray. It was demonstrated that long-term treatment with SBP improves glucose homeostasis, increases insulin sensitivity, and lowers plasma triglycerides in diabetic KKAy-mice. SBP reduces fasting plasma glucose, insulin, triglycerides, and total cholesterol. Furthermore, SBP markedly changes the gene expression profile of key insulin regulatory genes GLUT2, GLUT3, Ins1, Ins2, IGF1, Beta2/Neurod1, cholecystokinin, and LDLr, and proliferative genes in islets isolated from KKAy-mice. After 9 weeks of treatment with SBP, plasma glucose and insulin homeostasis was normalized compared to start levels. The results indicate that SBP improves glucose and insulin sensitivity and up-regulates the expression of key insulin regulatory genes.

  8. Knockout of Na-glucose transporter SGLT2 attenuates hyperglycemia and glomerular hyperfiltration but not kidney growth or injury in diabetes mellitus

    Science.gov (United States)

    Rose, Michael; Gerasimova, Maria; Satriano, Joseph; Platt, Kenneth A.; Koepsell, Hermann; Cunard, Robyn; Sharma, Kumar; Thomson, Scott C.; Rieg, Timo

    2013-01-01

    The Na-glucose cotransporter SGLT2 mediates high-capacity glucose uptake in the early proximal tubule and SGLT2 inhibitors are developed as new antidiabetic drugs. We used gene-targeted Sglt2 knockout (Sglt2−/−) mice to elucidate the contribution of SGLT2 to blood glucose control, glomerular hyperfiltration, kidney growth, and markers of renal growth and injury at 5 wk and 4.5 mo after induction of low-dose streptozotocin (STZ) diabetes. The absence of SGLT2 did not affect renal mRNA expression of glucose transporters SGLT1, NaGLT1, GLUT1, or GLUT2 in response to STZ. Application of STZ increased blood glucose levels to a lesser extent in Sglt2−/− vs. wild-type (WT) mice (∼300 vs. 470 mg/dl) but increased glucosuria and food and fluid intake to similar levels in both genotypes. Lack of SGLT2 prevented STZ-induced glomerular hyperfiltration but not the increase in kidney weight. Knockout of SGLT2 attenuated the STZ-induced renal accumulation of p62/sequestosome, an indicator of impaired autophagy, but did not attenuate the rise in renal expression of markers of kidney growth (p27 and proliferating cell nuclear antigen), oxidative stress (NADPH oxidases 2 and 4 and heme oxygenase-1), inflammation (interleukin-6 and monocyte chemoattractant protein-1), fibrosis (fibronectin and Sirius red-sensitive tubulointerstitial collagen accumulation), or injury (renal/urinary neutrophil gelatinase-associated lipocalin). SGLT2 deficiency did not induce ascending urinary tract infection in nondiabetic or diabetic mice. The results indicate that SGLT2 is a determinant of hyperglycemia and glomerular hyperfiltration in STZ-induced diabetes mellitus but is not critical for the induction of renal growth and markers of renal injury, inflammation, and fibrosis. PMID:23152292

  9. Candidate gene association study in type 2 diabetes indicates a role for genes involved in beta-cell function as well as insulin action.

    Directory of Open Access Journals (Sweden)

    Inês Barroso

    2003-10-01

    Full Text Available Type 2 diabetes is an increasingly common, serious metabolic disorder with a substantial inherited component. It is characterised by defects in both insulin secretion and action. Progress in identification of specific genetic variants predisposing to the disease has been limited. To complement ongoing positional cloning efforts, we have undertaken a large-scale candidate gene association study. We examined 152 SNPs in 71 candidate genes for association with diabetes status and related phenotypes in 2,134 Caucasians in a case-control study and an independent quantitative trait (QT cohort in the United Kingdom. Polymorphisms in five of 15 genes (33% encoding molecules known to primarily influence pancreatic beta-cell function-ABCC8 (sulphonylurea receptor, KCNJ11 (KIR6.2, SLC2A2 (GLUT2, HNF4A (HNF4alpha, and INS (insulin-significantly altered disease risk, and in three genes, the risk allele, haplotype, or both had a biologically consistent effect on a relevant physiological trait in the QT study. We examined 35 genes predicted to have their major influence on insulin action, and three (9%-INSR, PIK3R1, and SOS1-showed significant associations with diabetes. These results confirm the genetic complexity of Type 2 diabetes and provide evidence that common variants in genes influencing pancreatic beta-cell function may make a significant contribution to the inherited component of this disease. This study additionally demonstrates that the systematic examination of panels of biological candidate genes in large, well-characterised populations can be an effective complement to positional cloning approaches. The absence of large single-gene effects and the detection of multiple small effects accentuate the need for the study of larger populations in order to reliably identify the size of effect we now expect for complex diseases.

  10. Trivaric acid, a new inhibitor of PTP1b with potent beneficial effect on diabetes.

    Science.gov (United States)

    Sun, Wenlong; Zhang, Bowei; Zheng, Haizhou; Zhuang, Chunlin; Li, Xia; Lu, Xinhua; Quan, Chunshan; Dong, Yuesheng; Zheng, Zhihui; Xiu, Zhilong

    2017-01-15

    To screen a potential PTP1b inhibitor from the microbial origin-based compound library and to investigate the potential anti-diabetic effects of the inhibitor in vivo and determine its primary anti-diabetic mechanism in vitro and in silico. PTP1b inhibitory activity was measured using recombination protein as the enzyme and p-NPP as the substrate. The binding of the inhibitor to PTP1b was analysed by docking in silico and confirmed by ITC experiments. The intracellular signalling pathway was detected by Western blot analysis in HepG2 cells. The anti-diabetic effects were evaluated using a diabetic mice model in vivo. Among 545 microbial origin-based pure compounds tested, trivaric acid, a tridepside, was selected as a PTP1B inhibitor exhibiting strong inhibitory activity with an IC 50 of 173nM. Docking and ITC studies showed that trivaric acid was able to spontaneously bind to PTP1b and may inhibit PTP1b by blocking the catalytic domain of the phosphatase. Trivaric acid also enhanced the ability of insulin to stimulate the IR/IRS/Akt/GLUT2 pathway and increase the glucose consumption in HepG2 cells. In diabetic mice, trivaric acid that had been encapsulated into Eudrgit L100-5.5 showed significant anti-diabetic effects, improving insulin resistance, leptin resistance and lipid profile and weight control at doses of 5mg/kg and 50mg/kg. Trivaric acid is a potential lead compound in the search for anti-diabetic agents targeting PTP1b. Copyright © 2016 Elsevier Inc. All rights reserved.

  11. Rare sugar D-allulose: Potential role and therapeutic monitoring in maintaining obesity and type 2 diabetes mellitus.

    Science.gov (United States)

    Hossain, Akram; Yamaguchi, Fuminori; Matsuo, Tatsuhiro; Tsukamoto, Ikuko; Toyoda, Yukiyasu; Ogawa, Masahiro; Nagata, Yasuo; Tokuda, Masaaki

    2015-11-01

    Obesity and type 2 diabetes mellitus (T2DM) are the leading worldwide risk factors for mortality. The inextricably interlinked pathological progression from excessive weight gain, obesity, and hyperglycemia to T2DM, usually commencing from obesity, typically originates from overconsumption of sugar and high-fat diets. Although most patients require medications, T2DM is manageable or even preventable with consumption of low-calorie diet and maintaining body weight. Medicines like insulin, metformin, and thiazolidinediones that improve glycemic control; however, these are associated with weight gain, high blood pressure, and dyslipidemia. These situations warrant the attentive consideration of the role of balanced foods. Recently, we have discovered advantages of a rare sugar, D-allulose, a zero-calorie functional sweetener having strong anti-hyperlipidemic and anti-hyperglycemic effects. Study revealed that after oral administration in rats D-allulose readily entered the blood stream and was eliminated into urine within 24h. Cell culture study showed that D-allulose enters into and leaves the intestinal enterocytes via glucose transporters GLUT5 and GLUT2, respectively. In addition to D-allulose's short-term effects, the characterization of long-term effects has been focused on preventing commencement and progression of T2DM in diabetic rats. Human trials showed that D-allulose attenuates postprandial glucose levels in healthy subjects and in borderline diabetic subjects. The anti-hyperlipidemic effect of D-allulose, combined with its anti-inflammatory actions on adipocytes, is beneficial for the prevention of both obesity and atherosclerosis and is accompanied by improvements in insulin resistance and impaired glucose tolerance. Therefore, this review presents brief discussions focusing on physiological functions and potential benefits of D-allulose on obesity and T2DM. Copyright © 2015 Elsevier Inc. All rights reserved.

  12. Organ-specific gene expression: the bHLH protein Sage provides tissue specificity to Drosophila FoxA.

    Science.gov (United States)

    Fox, Rebecca M; Vaishnavi, Aria; Maruyama, Rika; Andrew, Deborah J

    2013-05-01

    FoxA transcription factors play major roles in organ-specific gene expression, regulating, for example, glucagon expression in the pancreas, GLUT2 expression in the liver, and tyrosine hydroxylase expression in dopaminergic neurons. Organ-specific gene regulation by FoxA proteins is achieved through cooperative regulation with a broad array of transcription factors with more limited expression domains. Fork head (Fkh), the sole Drosophila FoxA family member, is required for the development of multiple distinct organs, yet little is known regarding how Fkh regulates tissue-specific gene expression. Here, we characterize Sage, a bHLH transcription factor expressed exclusively in the Drosophila salivary gland (SG). We show that Sage is required for late SG survival and normal tube morphology. We find that many Sage targets, identified by microarray analysis, encode SG-specific secreted cargo, transmembrane proteins, and the enzymes that modify these proteins. We show that both Sage and Fkh are required for the expression of Sage target genes, and that co-expression of Sage and Fkh is sufficient to drive target gene expression in multiple cell types. Sage and Fkh drive expression of the bZip transcription factor Senseless (Sens), which boosts expression of Sage-Fkh targets, and Sage, Fkh and Sens colocalize on SG chromosomes. Importantly, expression of Sage-Fkh target genes appears to simply add to the tissue-specific gene expression programs already established in other cell types, and Sage and Fkh cannot alter the fate of most embryonic cell types even when expressed early and continuously.

  13. The effect of isorhamnetin glycosides extracted from Opuntia ficus-indica in a mouse model of diet induced obesity.

    Science.gov (United States)

    Rodríguez-Rodríguez, César; Torres, Nimbe; Gutiérrez-Uribe, Janet A; Noriega, Lilia G; Torre-Villalvazo, Iván; Leal-Díaz, Ana M; Antunes-Ricardo, Marilena; Márquez-Mota, Claudia; Ordaz, Guillermo; Chavez-Santoscoy, Rocío A; Serna-Saldivar, Sergio O; Tovar, Armando R

    2015-03-01

    A diet rich in polyphenols can ameliorate some metabolic alterations associated with obesity and type 2 diabetes. Opuntia ficus-indica (OFI) is a plant rich in isorhamnetin glycosides and is highly consumed in Mexico. The purpose of this research was to determine the metabolic effect of an OFI extract on a mouse model of diet-induced obesity and in isolated pancreatic islets. OFI extract was added to a high fat (HF) diet at a low (0.3%) or high (0.6%) dose and administered to C57BL/6 mice for 12 weeks. Mice fed the HF diet supplemented with the OFI extract gained less body weight and exhibited significantly lower circulating total cholesterol, LDL cholesterol and HDL cholesterol compared to those fed the HF diet alone. The HF-OFI diet fed mice presented lower glucose and insulin concentration than the HF diet fed mice. However, the HF-OFI diet fed mice tended to have higher insulin concentration than control mice. The OFI extract stimulated insulin secretion in vitro, associated with increased glucose transporter 2 (GLUT2) and peroxisome proliferator-activated receptor gamma (PPARγ) mRNA content. Furthermore, the OFI extract improved glucose tolerance, and additionally increased energy expenditure. These metabolic improvements were associated with reduced adipocyte size, increased hepatic IRS1 tyr-608 and S6 K thr-389 phosphorylation. OFI isorhamnetin glycosides also diminished the hepatic lipid content associated with reduced mRNA expression of the endoplasmic reticulum stress markers and lipogenic enzymes and increased mRNA expression of genes related to fatty acid oxidation. Overall, the OFI extract prevented the development of metabolic abnormalities associated with diet-induced obesity.

  14. Antidiabetic Effect of Galantamine: Novel Effect for a Known Centrally Acting Drug.

    Directory of Open Access Journals (Sweden)

    Mennatallah A Ali

    Full Text Available The cholinergic anti-inflammatory pathway is one of the putative biochemical pathways that link diabetes with Alzheimer disease. Hence, we aimed to verify the potential antidiabetic effect of galantamine, unveil the possible mechanisms and evaluate its interaction with vildagliptin. The n5-STZ rat model was adopted and the diabetic animals were treated with galantamine and/or vildagliptin for 4 weeks. Galantamine lowered the n5-STZ-induced elevation in body weight, food/water intake, serum levels of glucose, fructosamine, and ALT/AST, as well as AChE in the tested organs. Moreover, it modulated successfully the lipid profile assessed in serum, liver, and muscle, and increased serum insulin level, as well as % β-cell function, in a pattern similar to that of vildagliptin. Additionally, galantamine confirmed its antioxidant (Nrf2, TAC, MDA, anti-inflammatory (NF-κB, TNF-α, visfatin, adiponectin and anti-apoptotic (caspase-3, cytochrome c capabilities by altering the n5-STZ effect on all the aforementioned parameters. On the molecular level, galantamine/vildagliptin have improved the insulin (p-insulin receptor, p-Akt, GLUT4/GLUT2 and Wnt/β-catenin (p-GSK-3β, β-catenin signaling pathways. On almost all parameters, the galantamine effects surpassed that of vildagliptin, while the combination regimen showed the best effects. The present results clearly proved that galantamine modulated glucose/lipid profile possibly through its anti-oxidant, -apoptotic, -inflammatory and -cholinesterase properties. These effects could be attributed partly to the enhancement of insulin and Wnt/β-catenin signaling pathways. Galantamine can be strongly considered as a potential antidiabetic agent and as an add-on therapy with other oral antidiabetics.

  15. High Glucose Concentration Stimulates NHE-1 Activity in Distal Nephron Cells: the Role of the Mek/Erk1/2/p90RSK and p38MAPK Signaling Pathways

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    Juliana Martins da Costa-Pessoa

    2014-02-01

    Full Text Available Aims: In models of diabetes, distal nephron cells contribute to glucose uptake and oxidation. How these cells contribute to the use of glucose for the regulation of H+ extrusion remains unknown. We used Madin-Darby Canine Kidney (MDCK cells to investigate the effect of acute or chronic high glucose concentration on the abundance and activity of the Na+/H+ exchanger (NHE-1. Methods: Using RT-PCR, we also evaluated the mRNA expression for sodium glucose co-transporters SGLT1 and SGLT2. Protein abundance was analyzed using immunoblotting, and intracellular pH (pHi recovery was evaluated using microscopy in conjunction with the fluorescent probe BCECF/AM. The Na+-dependent pHi recovery rate was monitored with HOE-694 (50 µM and/or S3226 (10 µM, specific NHE-1 and NHE-3 inhibitors. Results: MDCK cells did not express the mRNA for SGLT1 or SGLT2 but did express the GLUT2, NHE-1 and NHE-3 proteins. Under control conditions, we observed a greater contribution of NHE-1 to pHi recovery relative to the other H+ transporters. Acute high glucose treatment increased the HOE-694-sensitive pHi recovery rate and p-Erk1/2 and p90RSK abundance. These parameters were reduced by PD-98059, a Mek inhibitor (1 µM. Chronic high glucose treatment also increased the HOE-694-sensitive pHi recovery rate and p-p38MAPK abundance. Both parameters were reduced by SB-203580, a p38MAPK inhibitor (10 µM. Conclusion: These results suggested that extracellular high glucose stimulated NHE-1 acutely and chronically through Mek/Erk1/2/p90RSK and p38MAPK pathways, respectively.

  16. Glucose Transporters in Diabetic Kidney Disease-Friends or Foes?

    Science.gov (United States)

    Wasik, Anita A; Lehtonen, Sanna

    2018-01-01

    Diabetic kidney disease (DKD) is a major microvascular complication of diabetes and a common cause of end-stage renal disease worldwide. DKD manifests as an increased urinary protein excretion (albuminuria). Multiple studies have shown that insulin resistance correlates with the development of albuminuria in non-diabetic and diabetic patients. There is also accumulating evidence that glomerular epithelial cells or podocytes are insulin sensitive and that insulin signaling in podocytes is essential for maintaining normal kidney function. At the cellular level, the mechanisms leading to the development of insulin resistance include mutations in the insulin receptor gene, impairments in the phosphoinositide 3-kinase (PI3K)/AKT signaling pathway, or perturbations in the trafficking of glucose transporters (GLUTs), which mediate the uptake of glucose into cells. Podocytes express several GLUTs, including GLUT1, GLUT2, GLUT3, GLUT4, and GLUT8. Of these, the most studied ones are GLUT1 and GLUT4, both shown to be insulin responsive in podocytes. In the basal state, GLUT4 is preferentially located in perinuclear and cytosolic vesicular structures and to a lesser extent at the plasma membrane. After insulin stimulation, GLUT4 is sorted into GLUT4-containing vesicles (GCVs) that translocate to the plasma membrane. GCV trafficking consists of several steps, including approaching of the GCVs to the plasma membrane, tethering, and docking, after which the lipid bilayers of the GCVs and the plasma membrane fuse, delivering GLUT4 to the cell surface for glucose uptake into the cell. Studies have revealed novel molecular regulators of the GLUT trafficking in podocytes and unraveled unexpected roles for GLUT1 and GLUT4 in the development of DKD, summarized in this review. These findings pave the way for better understanding of the mechanistic pathways associated with the development and progression of DKD and aid in the development of new treatments for this devastating disease.

  17. Baicalin and its metabolites suppresses gluconeogenesis through activation of AMPK or AKT in insulin resistant HepG-2 cells.

    Science.gov (United States)

    Wang, Tao; Jiang, Hongmei; Cao, Shijie; Chen, Qian; Cui, Mingyuan; Wang, Zhijie; Li, Dandan; Zhou, Jing; Wang, Tao; Qiu, Feng; Kang, Ning

    2017-12-01

    Scutellaria baicalensis Georgi (S. baicalensis), as a traditional Chinese herbal medicine, is an important component of several famous Chinese medicinal formulas for treating patients with diabetes mellitus. Baicalin (BG), a main bioactive component of S. baicalensis, has been reported to have antidiabetic effects. However, pharmacokinetic studies have indicated that BG has poor oral bioavailability. Therefore, it is hard to explain the pharmacological effects of BG in vivo. Interestingly, several reports show that BG is extensively metabolized in rats and humans. Therefore, we speculate that the BG metabolites might be responsible for the pharmacological effects. In this study, BG and its three metabolites (M1-M3) were examined their effects on glucose consumption in insulin resistant HepG-2 cells with a commercial glucose assay kit. Real-time PCR and western blot assay were used to confirm genes and proteins of interest, respectively. The results demonstrate that BG and its metabolites (except for M3) enhanced the glucose consumption which might be associated with inhibiting the expression of the key gluconeogenic genes, including glucose-6-phosphatase (G6Pase), phosphoenolypyruvate carboxykinase (PEPCK) and glucose transporter 2 (GLUT2). Further study found that BG and M1 could suppress hepatic gluconeogenesis via activation of the AMPK pathway, while M2 could suppress hepatic gluconeogenesis via activation of the PI3K/AKT signaling pathway. Taken together, our findings suggest that both BG and its metabolites have antihyperglycemic activities, and might be the active forms of oral doses of BG in vivo. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  18. Transient gestational exposure to drinking water containing excess hexavalent chromium modifies insulin signaling in liver and skeletal muscle of rat progeny.

    Science.gov (United States)

    Shobana, Navaneethabalakrishnan; Aruldhas, Mariajoseph Michael; Tochhawng, Lalmuankimi; Loganathan, Ayyalu; Balaji, Sadhasivam; Kumar, Mani Kathiresh; Banu, Liaquat Alikhan Sheerin; Navin, Ajit Kumar; Mayilvanan, Chinnaiyan; Ilangovan, Ramachandran; Balasubramanian, Karundevi

    2017-11-01

    Chromium (Cr), an essential micronutrient potentiates insulin action, whereas excess hexavalent Cr (CrVI) acts as an endocrine disruptor. Pregnant mothers living in areas abutting industries using the metal and chromite ore dumps are exposed to ground water contaminated with Cr. Nevertheless, the impact of prenatal exposure to excess CrVI on insulin signaling in the progeny remains obscure. We tested the hypothesis "transient gestational exposure to drinking water containing excess CrVI may modify insulin signaling during postnatal life". Pregnant Wistar rats were given drinking water containing 50, 100 and 200 ppm CrVI (K 2 Cr 2 O 7 ) from gestational day 9-14 encompassing the period of organogenesis; the male progenies were tested at postnatal day 60. Neither fasting blood glucose nor oral glucose tolerance was altered in CrVI treated progeny. Nevertheless, western blot detection pointed out attenuated expression level of insulin receptor (IR), its downstream signaling molecules (IRS-1, pIRS-1 Tyr632 , Akt and pAkt Ser473 ) and organ specific glucose transporters (GLUT2 in liver and GLUT4 in gastrocnemius muscle), along with a significant increase in serum insulin level in male progenies exposed to CrVI. While 14 C-2-deoxy glucose uptake increased in the liver, the same decreased in the skeletal muscle whereas, 14 C-glucose oxidation recorded a consistent decrease in both tissues of CrVI exposed rats. These findings support our hypothesis and suggest that transient gestational exposure to excess CrVI may affect insulin signaling and glucose oxidation in the progeny, predictably rendering them vulnerable to insulin resistance. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Postprandial kinetics of gene expression of proteins involved in the digestive process in rainbow trout (O. mykiss) and impact of diet composition.

    Science.gov (United States)

    Borey, Marion; Panserat, Stephane; Surget, Anne; Cluzeaud, Marianne; Plagnes-Juan, Elisabeth; Herman, Alexandre; Lazzarotto, Viviana; Corraze, Geneviève; Médale, Françoise; Lauga, Beatrice; Burel, Christine

    2016-08-01

    The impact of increased incorporation of plant ingredients on diets for rainbow trout was evaluated in terms of gene expression of gastric (gastric lipase, pepsinogen) and intestinal (prolidase, maltase, phospholipase A2) digestive enzymes and nutrient transporters (peptide and glucose transporters), as well as of postprandial levels of plasma glucose, triglycerides and total free amino acids. For that purpose, trout alevins were fed from the start of exogenous feeding one of three different experimental diets: a diet rich in fish meal and fish oil (FM-FO), a plant-based diet (noFM-noFO) totally free from fish meal and fish oil, but containing plant ingredients and a Mixed diet (Mixed) intermediate between the FM-FO and noFM-noFO diets. After 16 months of rearing, all fish were left unfed for 72 h and then given a single meal to satiation. Blood, stomach and anterior intestine were sampled before the meal and at 2, 6 and 12 h after this meal. The postprandial kinetics of gene expression of gastric and intestinal digestive enzymes and nutrient transporters were then followed in trout fed the FM-FO diet. The postprandial profiles showed that the expression of almost all genes studied was stimulated by the presence of nutrients in the digestive tract of trout, but the timing (appearance of peaks) varied between genes. Based on these data, we have focused on the molecular response to dietary factors in the stomach and the intestine at 6 and 12 h after feeding, respectively. The reduction in FM and FO levels of dietary incorporation induced a significant decrease in the gene expression of gastric lipase, GLUT2 and PEPT1. The plasma glucose and triglycerides levels were also reduced in trout fed the noFM-noFO diet. Consequently, the present study suggests a decrease in digestive capacities in trout fed a diet rich in plant ingredients.

  20. Transport, metabolism, and endosomal trafficking-dependent regulation of intestinal fructose absorption

    Science.gov (United States)

    Patel, Chirag; Douard, Veronique; Yu, Shiyan; Gao, Nan; Ferraris, Ronaldo P.

    2015-01-01

    Dietary fructose that is linked to metabolic abnormalities can up-regulate its own absorption, but the underlying regulatory mechanisms are not known. We hypothesized that glucose transporter (GLUT) protein, member 5 (GLUT5) is the primary fructose transporter and that fructose absorption via GLUT5, metabolism via ketohexokinase (KHK), as well as GLUT5 trafficking to the apical membrane via the Ras-related protein-in-brain 11 (Rab11)a-dependent endosomes are each required for regulation. Introducing fructose but not lysine and glucose solutions into the lumen increased by 2- to 10-fold the heterogeneous nuclear RNA, mRNA, protein, and activity levels of GLUT5 in adult wild-type mice consuming chow. Levels of GLUT5 were >100-fold that of candidate apical fructose transporters GLUTs 7, 8, and 12 whose expression, and that of GLUT 2 and the sodium-dependent glucose transporter protein 1 (SGLT1), was not regulated by luminal fructose. GLUT5-knockout (KO) mice exhibited no facilitative fructose transport and no compensatory increases in activity and expression of SGLT1 and other GLUTs. Fructose could not up-regulate GLUT5 in GLUT5-KO, KHK-KO, and intestinal epithelial cell-specific Rab11a-KO mice. The fructose-specific metabolite glyceraldehyde did not increase GLUT5 expression. GLUT5 is the primary transporter responsible for facilitative absorption of fructose, and its regulation specifically requires fructose uptake and metabolism and normal GLUT5 trafficking to the apical membrane.—Patel, C., Douard, V., Yu, S., Gao, N., Ferraris, R. P. Transport, metabolism, and endosomal trafficking-dependent regulation of intestinal fructose absorption. PMID:26071406

  1. Weekly intra-amniotic IGF-1 treatment increases growth of growth-restricted ovine fetuses and up-regulates placental amino acid transporters.

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    Jibran A Wali

    Full Text Available Frequent treatment of the growth-restricted (IUGR ovine fetus with intra-amniotic IGF-1 increases fetal growth. We aimed to determine whether increased growth was maintained with an extended dosing interval and to examine possible mechanisms. Pregnant ewes were allocated to three groups: Control, and two IUGR groups (induced by placental embolization treated with weekly intra-amniotic injections of either saline (IUGR or 360 µg IGF-1 (IGF1. IUGR fetuses were hypoxic, hyperuremic, hypoglycemic, and grew more slowly than controls. Placental glucose uptake and SLC2A1 (GLUT2 mRNA levels decreased in IUGR fetuses, but SLC2A3 (GLUT3 and SLC2A4 (GLUT4 levels were unaffected. IGF-1 treatment increased fetal growth rate, did not alter uterine blood flow or placental glucose uptake, and increased placental SLC2A1 and SLC2A4 (but not SLC2A3 mRNA levels compared with saline-treated IUGR animals. Following IGF-1 treatment, placental mRNA levels of isoforms of the system A, y(+, and L amino acid transporters increased 1.3 to 5.0 fold, while the ratio of phosphorylated-mTOR to total mTOR also tended to increase. Weekly intra-amniotic IGF-1 treatment provides a promising avenue for intra-uterine treatment of IUGR babies, and may act via increased fetal substrate supply, up-regulating placental transporters for neutral, cationic, and branched-chain amino acids, possibly via increased activation of the mTOR pathway.

  2. Mobilization and removing of cadmium from kidney by GMDTC utilizing renal glucose reabsorption pathway

    International Nuclear Information System (INIS)

    Tang, Xiaojiang; Zhu, Jinqiu; Zhong, Zhiyong; Luo, Minhui; Li, Guangxian; Gong, Zhihong; Zhang, Chenzi; Fei, Fan; Ruan, Xiaolin; Zhou, Jinlin; Liu, Gaofeng; Li, Guoding; Olson, James; Ren, Xuefeng

    2016-01-01

    Chronic exposure to cadmium compounds (Cd 2+ ) is one of the major public health problems facing humans in the 21st century. Cd 2+ in the human body accumulates primarily in the kidneys which leads to renal dysfunction and other adverse health effects. Efforts to find a safe and effective drug for removing Cd 2+ from the kidneys have largely failed. We developed and synthesized a new chemical, sodium (S)-2-(dithiocarboxylato((2S,3R,4R,5R)-2,3,4,5,6 pentahydroxyhexyl)amino)-4-(methylthio) butanoate (GMDTC). Here we report that GMDTC has a very low toxicity with an acute lethal dose (LD50) of more than 10,000 mg/kg or 5000 mg/kg body weight, respectively, via oral or intraperitoneal injection in mice and rats. In in vivo settings, up to 94% of Cd 2+ deposited in the kidneys of Cd 2+ -laden rabbits was removed and excreted via urine following a safe dose of GMDTC treatment for four weeks, and renal Cd 2+ level was reduced from 12.9 μg/g to 1.3 μg/g kidney weight. We observed similar results in the mouse and rat studies. Further, we demonstrated both in in vitro and in animal studies that the mechanism of transporting GMDTC and GMDTC-Cd complex into and out of renal tubular cells is likely assisted by two glucose transporters, sodium glucose cotransporter 2 (SGLT2) and glucose transporter 2 (GLUT2). Collectively, our study reports that GMDTC is safe and highly efficient in removing deposited Cd 2+ from kidneys assisted by renal glucose reabsorption system, suggesting that GMDTC may be the long-pursued agent used for preventive and therapeutic purposes for both acute and chronic Cd 2+ exposure.

  3. Hydrogen improves glycemic control in type1 diabetic animal model by promoting glucose uptake into skeletal muscle.

    Directory of Open Access Journals (Sweden)

    Haruka Amitani

    Full Text Available Hydrogen (H(2 acts as a therapeutic antioxidant. However, there are few reports on H(2 function in other capacities in diabetes mellitus (DM. Therefore, in this study, we investigated the role of H(2 in glucose transport by studying cultured mouse C2C12 cells and human hepatoma Hep-G2 cells in vitro, in addition to three types of diabetic mice [Streptozotocin (STZ-induced type 1 diabetic mice, high-fat diet-induced type 2 diabetic mice, and genetically diabetic db/db mice] in vivo. The results show that H(2 promoted 2-[(14C]-deoxy-d-glucose (2-DG uptake into C2C12 cells via the translocation of glucose transporter Glut4 through activation of phosphatidylinositol-3-OH kinase (PI3K, protein kinase C (PKC, and AMP-activated protein kinase (AMPK, although it did not stimulate the translocation of Glut2 in Hep G2 cells. H(2 significantly increased skeletal muscle membrane Glut4 expression and markedly improved glycemic control in STZ-induced type 1 diabetic mice after chronic intraperitoneal (i.p. and oral (p.o. administration. However, long-term p.o. administration of H(2 had least effect on the obese and non-insulin-dependent type 2 diabetes mouse models. Our study demonstrates that H(2 exerts metabolic effects similar to those of insulin and may be a novel therapeutic alternative to insulin in type 1 diabetes mellitus that can be administered orally.

  4. A maternal high-protein diet predisposes female offspring to increased fat mass in adulthood whereas a prebiotic fibre diet decreases fat mass in rats.

    Science.gov (United States)

    Hallam, Megan C; Reimer, Raylene A

    2013-11-14

    The negative effects of malnourishment in utero have been widely explored; the effects of increased maternal macronutrient intake are not known in relation to high fibre, and have been inconclusive with regard to high protein. In the present study, virgin Wistar dams were fed either a control (C), high-protein (40 %, w/w; HP) or high-prebiotic fibre (21·6 %, w/w; HF) diet throughout pregnancy and lactation. Pups consumed the C diet from 3 to 14·5 weeks of age, and then switched to a high-fat/sucrose diet for 8 weeks. A dual-energy X-ray absorptiometry scan and an oral glucose tolerance test were performed and plasma satiety hormones measured. The final body weight and the percentage of body fat were significantly affected by the interaction between maternal diet and offspring sex: weight and fat mass were higher in the female offspring of the HP v. HF dams. No differences in body weight or fat mass were seen in the male offspring. There was a significant sex effect for fasting and total AUC for ghrelin and fasting GIP, with females having higher levels than males. Liver TAG content and plasma NEFA were lower in the offspring of high-prebiotic fibre dams (HF1) than in those of high-protein dams (HP1) and control dams (C1). Intestinal expression of GLUT2 was decreased in HF1 and HP1 v. C1. The maternal HP and HF diets had lasting effects on body fat and hepatic TAG accumulation in the offspring, particularly in females. Whereas the HP diet predisposes to an obese phenotype, the maternal HF diet appears to reduce the susceptibility to obesity following a high-energy diet challenge in adulthood.

  5. The effect of folate status on the uptake of physiologically relevant compounds by Caco-2 cells.

    Science.gov (United States)

    Tavares, Sandra; Sousa, Joana; Gonçalves, Pedro; Araújo, João R; Martel, Fátima

    2010-08-25

    The aim of this work was to investigate the effect of folate status on the uptake of several physiologically relevant substances by Caco-2 cells. For this, Caco-2 cells cultured in high-folate conditions (HF) and low-folate conditions (LF) were compared. Growth rates of HF and LF Caco-2 cells were similar. However, proliferation rate of LF cells was greater than that of HF cells during the first 2days of culture and slightly smaller thereafter, viability of LF cells was greater than that of HF cells, and apoptosis index was similar in both cell cultures. We verified that in LF cells, comparatively to HF cells: (1) uptake of [3H]folic acid is upregulated, via an increase in the Vmax of uptake; (2) uptake of [3H]deoxy-glucose, [3H]O-methyl-glucose and [3H]1-methyl-4-phenylpyridinium (MPP+) is downregulated, via a decrease in the Vmax of uptake; additionally, a reduction in Km was observed for [3H]O-methyl-glucose; (3) uptake of [3H]5-hydroxytryptamine and [14C]butyrate is not changed; and (4) the steady-state mRNA levels of the folic acid transporters RFC (reduced folate carrier), PCFT (proton-coupled folate transporter) and FRalpha (folate receptor alpha), of the organic cation transporter OCT1 (organic cation transporter type 1), of the glucose transporter GLUT2 (facilitative glucose transporter type 2) and of the butyrate transporter MCT1 (monocarboxylate transporter type 1) were decreased. In conclusion, folate deficiency produces substrate-specific changes in the uptake of bioactive compounds by Caco-2 cells. Moreover, these changes are associated with alterations in the mRNA levels of specific transporters for these compounds. Copyright (c) 2010 Elsevier B.V. All rights reserved.

  6. Mobilization and removing of cadmium from kidney by GMDTC utilizing renal glucose reabsorption pathway

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Xiaojiang, E-mail: river-t@126.com [Guangdong Medical Laboratory Animal Center (China); Zhu, Jinqiu [Department of Epidemiology and Environmental Health, The State University of New York, Buffalo, NY (United States); Zhong, Zhiyong; Luo, Minhui; Li, Guangxian [Guangdong Medical Laboratory Animal Center (China); Gong, Zhihong [Department of Epidemiology and Environmental Health, The State University of New York, Buffalo, NY (United States); Zhang, Chenzi; Fei, Fan [Guangdong Medical Laboratory Animal Center (China); Ruan, Xiaolin [Guangdong Poison Control Center (China); Zhou, Jinlin [Golden Health (Foshan) Technology Co., Ltd (China); Liu, Gaofeng [School of Chemistry and Chemical Engineering, Sun Yat-Sen University (China); Li, Guoding [Guangdong Medical Laboratory Animal Center (China); Olson, James [Department of Epidemiology and Environmental Health, The State University of New York, Buffalo, NY (United States); Department of Pharmacology and Toxicology, The State University of New York, Buffalo, NY (United States); Ren, Xuefeng, E-mail: xuefengr@buffalo.edu [Guangdong Medical Laboratory Animal Center (China); Department of Epidemiology and Environmental Health, The State University of New York, Buffalo, NY (United States); Department of Pharmacology and Toxicology, The State University of New York, Buffalo, NY (United States)

    2016-08-15

    Chronic exposure to cadmium compounds (Cd{sup 2+}) is one of the major public health problems facing humans in the 21st century. Cd{sup 2+} in the human body accumulates primarily in the kidneys which leads to renal dysfunction and other adverse health effects. Efforts to find a safe and effective drug for removing Cd{sup 2+} from the kidneys have largely failed. We developed and synthesized a new chemical, sodium (S)-2-(dithiocarboxylato((2S,3R,4R,5R)-2,3,4,5,6 pentahydroxyhexyl)amino)-4-(methylthio) butanoate (GMDTC). Here we report that GMDTC has a very low toxicity with an acute lethal dose (LD50) of more than 10,000 mg/kg or 5000 mg/kg body weight, respectively, via oral or intraperitoneal injection in mice and rats. In in vivo settings, up to 94% of Cd{sup 2+} deposited in the kidneys of Cd{sup 2+}-laden rabbits was removed and excreted via urine following a safe dose of GMDTC treatment for four weeks, and renal Cd{sup 2+} level was reduced from 12.9 μg/g to 1.3 μg/g kidney weight. We observed similar results in the mouse and rat studies. Further, we demonstrated both in in vitro and in animal studies that the mechanism of transporting GMDTC and GMDTC-Cd complex into and out of renal tubular cells is likely assisted by two glucose transporters, sodium glucose cotransporter 2 (SGLT2) and glucose transporter 2 (GLUT2). Collectively, our study reports that GMDTC is safe and highly efficient in removing deposited Cd{sup 2+} from kidneys assisted by renal glucose reabsorption system, suggesting that GMDTC may be the long-pursued agent used for preventive and therapeutic purposes for both acute and chronic Cd{sup 2+} exposure.

  7. The transcription of MGAT4A glycosyl transferase is increased in white cells of peripheral blood of Type 2 Diabetes patients

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    Cruz Miguel

    2007-10-01

    Full Text Available Abstract Background Human glycosylase IV is involved in GLUT2 transporter regulation in pancreatic β cells. A KO of this gene along with a high fat diet in a mice model has been associated with the development of type 2 diabetes (T2D. The aims of this study were to measure and compare the MGAT4A mRNA levels in white blood cells (WBC from T2D subjects and healthy subjects (T2NB, and to measure the half-life of the MGAT4A mRNA. Results We studied a sample of 73 individuals, 40 T2D subjects and 33 T2NB subjects. Anthropometrical and biochemical profiles were registered. The MGAT4A mRNA levels in WBC and the transcript half-life in Jurkat T cells were determined by Real-Time PCR. A blood differential cell counting was made for each individual. Cell counting showed T2D subjects exhibited an increased number of WBC compared to T2NB subjects (P = 0.0001. Biochemical parameters such as fasting glucose (P = 0.0001, and triglycerides (P = 0.002 were statistically significant. T2D subjects had 4.2-fold more MGAT4A transcript compared to T2NB subjects (P = 0.002. The MGAT4A mRNA had a half-life of 2.04 h in Jurkat T cells. Conclusion The results of this work suggest that in T2D subjects, high levels of glucose and triglycerides are accompanied by an increase on MGAT4A mRNA levels and WBC count; condition that suggests a pro-inflammatory state due to a chronic metabolic stress.

  8. Hexose transporter mRNAs for GLUT4, GLUT5, and GLUT12 predominate in human muscle.

    Science.gov (United States)

    Stuart, Charles A; Yin, Deling; Howell, Mary E A; Dykes, Rhesa J; Laffan, John J; Ferrando, Arny A

    2006-11-01

    In the past few years, 8 additional members of the facilitative hexose transporter family have been identified, giving a total of 14 members of the SLC2A family of membrane-bound hexose transporters. To determine which of the new hexose transporters were expressed in muscle, mRNA concentrations of 11 glucose transporters (GLUTs) were quantified and compared. RNA from muscle from 10 normal volunteers was subjected to RT-PCR. Primers were designed that amplified 78- to 241-base fragments, and cDNA standards were cloned for GLUT1, GLUT2, GLUT3, GLUT4, GLUT5, GLUT6, GLUT8, GLUT9, GLUT10, GLUT11, GLUT12, and GAPDH. Seven of these eleven hexose transporters were detectable in normal human muscle. The rank order was GLUT4, GLUT5, GLUT12, GLUT8, GLUT11, GLUT3, and GLUT1, with corresponding concentrations of 404 +/- 49, 131 +/- 14, 33 +/- 4, 5.5 +/- 0.5, 4.1 +/- 0.4, 1.2 +/- .0.1, and 0.9 +/- 0.2 copies/ng RNA (means +/- SE), respectively, for the 10 subjects. Concentrations of mRNA for GLUT4, GLUT5, and GLUT12 were much higher than those for the remainder of the GLUTs and together accounted for 98% of the total GLUT isoform mRNA. Immunoblots of muscle homogenates verified that the respective proteins for GLUT4, GLUT5, and GLUT12 were present in normal human muscle. Immunofluorescent studies demonstrated that GLUT4 and GLUT12 were predominantly expressed in type I oxidative fibers; however, GLUT5 was expressed predominantly in type II (white) fibers.

  9. Intervention of D-glucose ameliorates the toxicity of streptozotocin in accessory sex organs of rat

    International Nuclear Information System (INIS)

    Vikram, A.; Tripathi, D.N.; Ramarao, P.; Jena, G.B.

    2008-01-01

    Streptozotocin (STZ) is a naturally occurring compound isolated from Streptomyces achromogens. It is used extensively for inducing diabetes in experimental animals. Diabetes mellitus is known to have proven adverse effects on male sexual organs and their reproductive functions. The atrophy of prostate gland and other organs of the genitourinary tract were observed in experimental diabetic animals. STZ exhibits a structural resemblance to D-glucose due to the presence of sugar moiety in its structure. Pancreatic β-cells mainly contain GLUT1 and GLUT2 glucose transporters. Possibly due to structural resemblance, STZ and D-glucose, share a common recognition site for entry into the β-cells. The objective of the present study is to evaluate the effect of D-glucose on STZ-induced toxicity in accessory sex organs of male rats. Animals were kept on overnight fasting. One group received vehicle and served as negative control, while all other groups were given STZ (45 mg/kg). Animals that received only STZ served as positive control. The effect of D-glucose was studied on STZ treated animals with different dosage of D-glucose (250, 500, 1000 and 2000 mg/kg). Restoration of body weight, plasma glucose and plasma insulin was evident only at 1000 and 2000 mg/kg of D-glucose. The protective effect of D-glucose is evident only when it is administered simultaneously with STZ. In the present investigation, we report that simultaneous administration of D-glucose along with STZ ameliorates STZ-induced toxicity. This is evident from the restoration of accessory sex organ's weight, cellular morphology as well as insulin level

  10. Vitamin C deficiency aggravates tumor necrosis factor α-induced insulin resistance.

    Science.gov (United States)

    Qing, Zhou; Xiao-Hui, Wu; Xi-Mei, Wu; Chao-Chun, Zou

    2018-06-15

    Chronic low-grade inflammation plays a major role in the development of insulin resistance. The potential role and underlying mechanism of vitamin C, an antioxidant and anti-inflammatory agent, was investigated in tumor necrosis factor-α (TNF-α)-induced insulin resistance. Gulonolactone oxidase knockout (Gulo -/- ) mice genetically unable to synthesize vitamin C were used to induce insulin resistance by continuously pumping small doses of TNF-α for seven days, and human liver hepatocellular carcinoma cells (HepG2 cells) were used to induce insulin resistance by treatment with TNF-α. Vitamin C deficiency aggravated TNF-α-induced insulin resistance in Gulo -/- mice, resulting in worse glucose tolerance test (GTT) results, higher fasting plasma insulin level, and the inactivation of the protein kinase B (AKT)/glycogen synthase kinase-3β (GSK3β) pathway in the liver. Vitamin C deficiency also worsened liver lipid accumulation and inflammation in TNF-α-treated Gulo -/- mice. In HepG2 cells, vitamin C reversed the TNF-α-induced reduction of glucose uptake and glycogen synthesis, which were mediated by increasing GLUT2 levels and the activation of the insulin receptor substrate (IRS-1)/AKT/GSK3β pathway. Furthermore, vitamin C inhibited the TNF-α-induced activation of not only the mitogen-activated protein kinase (MAPKs), but also nuclear factor-kappa B (NF-κB) signaling. Taken together, vitamin C is essential for preventing and improving insulin resistance, and the supplementing with vitamin C may be an effective therapeutic intervention for metabolic disorders. Copyright © 2018 Elsevier B.V. All rights reserved.

  11. Ebselen pretreatment attenuates ischemia/reperfusion injury and prevents hyperglycemia by improving hepatic insulin signaling and β-cell survival in gerbils.

    Science.gov (United States)

    Park, S; Kang, S; Kim, D S; Shin, B K; Moon, N R; Daily, J W

    2014-08-01

    Transient carotid artery occlusion causes ischemia/reperfusion (I/R) injury resulting in neuron and pancreatic β-cell death with consequential post-stroke hyperglycemia, which can lead to diabetes and may accelerate the development of Alzheimer's disease. Antioxidants have been shown to protect against the I/R injury and destruction of neurons. However, it is unknown whether the protection against I/R injury extends to the pancreatic β-cells. Therefore, we investigated whether treatment with ebselen, a glutathione peroxidase mimic, prevents neuronal and β-cell death following I/R in gerbils susceptible to stroke. After 28 days post artery occlusion, there was widespread neuronal cell death in the CA1 of the hippocampus and elevated IL-1β and TNF-α levels. Pretreatment with ebselen prevented the death by 56% and attenuated neurological damage (abnormal eyelid drooping, hair bristling, muscle tone, flexor reflex, posture, and walking patterns). Ischemic gerbils also exhibited impaired glucose tolerance and insulin sensitivity which induced post-stroke hyperglycemia associated with decreased β-cell mass due to increased β-cell apoptosis. Ebselen prevented the increased β-cell apoptosis, possibly by decreasing IL-1β and TNF-α in islets. Ischemia also attenuated hepatic insulin signaling, and expression of GLUT2 and glucokinase, whereas ebselen prevented the attenuation and suppressed gluconeogenesis by decreasing PEPCK expression. In conclusion, antioxidant protection by ebselen attenuated I/R injury of neurons and pancreatic β-cells and prevented subsequent impairment of glucose regulation that could lead to diabetes and Alzheimer's disease.

  12. JTC801 Induces pH-dependent Death Specifically in Cancer Cells and Slows Growth of Tumors in Mice.

    Science.gov (United States)

    Song, Xinxin; Zhu, Shan; Xie, Yangchun; Liu, Jiao; Sun, Lingyi; Zeng, Dexing; Wang, Pengcheng; Ma, Xiaochao; Kroemer, Guido; Bartlett, David L; Billiar, Timothy R; Lotze, Michael T; Zeh, Herbert J; Kang, Rui; Tang, Daolin

    2018-04-01

    Maintenance of acid-base homeostasis is required for normal physiology, metabolism, and development. It is not clear how cell death is activated in response to changes in pH. We performed a screen to identify agents that induce cell death in a pH-dependent manner (we call this alkaliptosis) in pancreatic ductal adenocarcinoma cancer (PDAC) cells and tested their effects in mice. We screened a library of 254 compounds that interact with G-protein-coupled receptors (GPCRs) to identify those with cytotoxic activity against a human PDAC cell line (PANC1). We evaluated the ability of JTC801, which binds the opiod receptor and has analgesic effects, to stimulate cell death in human PDAC cell lines (PANC1, MiaPaCa2, CFPAC1, PANC2.03, BxPc3, and CAPAN2), mouse pancreatic cancer-associated stellate cell lines, primary human pancreatic ductal epithelial cells, and 60 cancer cell lines (the NCI-60 panel). Genes encoding proteins in cell death and GPCR signaling pathways, as well as those that regulate nuclear factor-κB (NF-κB) activity, were knocked out, knocked down, or expressed from transgenes in cancer cell lines. JTC801 was administered by gavage to mice with xenograft tumors, C57BL/6 mice with orthographic pancreatic tumors grown from Pdx1-Cre;KRas G12D/+ ;Tp53 R172H/+ (KPC) cells, mice with metastases following tail-vein injection of KPC cells, and Pdx-1-Cre;Kras G12D/+ mice crossed with Hmgb1 flox/flox mice (KCH mice). Pancreata were collected from mice and analyzed for tumor growth and by histology and immunohistochemistry. We compared gene and protein expression levels between human pancreatic cancer tissues and patient survival times using online R2 genomic or immunohistochemistry analyses. Exposure of human PDAC cell lines (PANC1 and MiaPaCa2) to JTC801 did not induce molecular markers of apoptosis (cleavage of caspase 3 or poly [ADP ribose] polymerase [PARP]), necroptosis (interaction between receptor-interacting serine-threonine kinase 3 [RIPK3] and mixed

  13. Observation sequences and onboard data processing of Planet-C

    Science.gov (United States)

    Suzuki, M.; Imamura, T.; Nakamura, M.; Ishi, N.; Ueno, M.; Hihara, H.; Abe, T.; Yamada, T.

    Planet-C or VCO Venus Climate Orbiter will carry 5 cameras IR1 IR 1micrometer camera IR2 IR 2micrometer camera UVI UV Imager LIR Long-IR camera and LAC Lightning and Airglow Camera in the UV-IR region to investigate atmospheric dynamics of Venus During 30 hr orbiting designed to quasi-synchronize to the super rotation of the Venus atmosphere 3 groups of scientific observations will be carried out i image acquisition of 4 cameras IR1 IR2 UVI LIR 20 min in 2 hrs ii LAC operation only when VCO is within Venus shadow and iii radio occultation These observation sequences will define the scientific outputs of VCO program but the sequences must be compromised with command telemetry downlink and thermal power conditions For maximizing science data downlink it must be well compressed and the compression efficiency and image quality have the significant scientific importance in the VCO program Images of 4 cameras IR1 2 and UVI 1Kx1K and LIR 240x240 will be compressed using JPEG2000 J2K standard J2K is selected because of a no block noise b efficiency c both reversible and irreversible d patent loyalty free and e already implemented as academic commercial software ICs and ASIC logic designs Data compression efficiencies of J2K are about 0 3 reversible and 0 1 sim 0 01 irreversible The DE Digital Electronics unit which controls 4 cameras and handles onboard data processing compression is under concept design stage It is concluded that the J2K data compression logics circuits using space

  14. In-Orbit Spectral Response Function Correction and Its Impact on Operational Calibration for the Long-Wave Split-Window Infrared Band (12.0 μm of FY-2G Satellite

    Directory of Open Access Journals (Sweden)

    Qiang Guo

    2017-06-01

    Full Text Available During the early stage of the G satellite of the Fengyun-2 series (FY-2G, severe cold biases up to ~2.3 K occur in its measurements in the 12.0 μm (IR2 band, which demonstrate time- and scene-dependent characteristics. Similar cold biases in water vapor and carbon dioxide absorption bands of other satellites are considered to be caused by either ice contamination (physical method or spectral response function (SRF shift (empirical method. Simulations indicate that this cold bias of FY-2G indeed suffers from equivalent SRF shift as a whole towards the longer wavelength direction. To overcome it, a novel approach combining both physical and empirical methods is proposed. With the possible ice thicknesses tested before launch, the ice contamination effect is alleviated, while the shape of the SRF can be modified in a physical way. The remaining unknown factors for cold bias are removed by shifting the convolved SRF with an ice transmittance spectrum. Two parameters, i.e., the ice thickness (5 μm and the shifted value (+0.15 μm, are estimated by inter-calibration with reference instruments, and the modification coefficient is also calculated (0.9885 for the onboard blackbody calibration. Meanwhile, the updated SRF was released online on 23 March 2016. For the period between July 2015 and December 2016, the monthly biases of the FY-2G IR2 band remain oscillating around zero, the majorities (~89% of which are within ±1.0 K, while its mean monthly absolute bias is around 0.6 K. Nevertheless, the cold bias phenomenon of the IR2 band no longer exists. The combination method can be referred by other corrections for cold biases.

  15. A Search for Water Maser Emission from Brown Dwarfs and Low-luminosity Young Stellar Objects

    Energy Technology Data Exchange (ETDEWEB)

    Gómez, José F.; Manjarrez, Guillermo [Instituto de Astrofísica de Andalucía, CSIC, Glorieta de la Astronomía s/n, E-18008 Granada (Spain); Palau, Aina [Instituto de Radioastronomía y Astrofísica, UNAM, P.O. Box 3-72, 58090, Morelia, Michoacán, México (Mexico); Uscanga, Lucero [Departamento de Astronomía, Universidad de Guanajuato, A.P. 144, 36000 Guanajuato, Gto., México (Mexico); Barrado, David, E-mail: jfg@iaa.es [Centro de Astrobiología, INTA-CSIC, PO BOX 28692, ESAC Campus, E-208691 Villanueva de la Cañada, Madrid (Spain)

    2017-05-01

    We present a survey for water maser emission toward a sample of 44 low-luminosity young objects, comprising (proto-)brown dwarfs, first hydrostatic cores (FHCs), and other young stellar objects (YSOs) with bolometric luminosities lower than 0.4 L {sub ⊙}. Water maser emission is a good tracer of energetic processes, such as mass-loss and/or accretion, and is a useful tool to study these processes with very high angular resolution. This type of emission has been confirmed in objects with L {sub bol} ≳ 1 L {sub ⊙}. Objects with lower luminosities also undergo mass-loss and accretion, and thus, are prospective sites of maser emission. Our sensitive single-dish observations provided a single detection when pointing toward the FHC L1448 IRS 2E. However, follow-up interferometric observations showed water maser emission associated with the nearby YSO L1448 IRS 2 (a Class 0 protostar of L {sub bol} ≃ 3.6–5.3 L {sub ⊙}) and did not find any emission toward L1448 IRS 2E. The upper limits for water maser emission determined by our observations are one order of magnitude lower than expected from the correlation between water maser luminosities and bolometric luminosities found for YSOs. This suggests that this correlation does not hold at the lower end of the (sub)stellar mass spectrum. Possible reasons are that the slope of this correlation is steeper at L {sub bol} ≤ 1 L {sub ⊙} or that there is an absolute luminosity threshold below which water maser emission cannot be produced. Alternatively, if the correlation still stands at low luminosity, the detection rates of masers would be significantly lower than the values obtained in higher-luminosity Class 0 protostars.

  16. Observation of the long-lived triplet excited state of perylenebisimide (PBI) in C^N cyclometalated Ir(III) complexes and application in photocatalytic oxidation.

    Science.gov (United States)

    Sun, Jifu; Zhong, Fangfang; Zhao, Jianzhang

    2013-07-14

    Perylenebisimide (PBI) was used to prepare C^N cyclometalated Ir(III) complexes that show strong absorption of visible light and it is the first time the long-lived triplet excited state of PBI chromophore was observed in a transition metal complex (τT = 22.3 μs). Previously, the lifetime of the triplet state of PBI in transition metal complexes was usually shorter than 1.0 μs. Long-lived triplet excited states are useful for applications in photocatalysis or other photophysical processes concerning triplet-triplet-energy-transfer. PBI and amino-PBI were used for preparation of cyclometalated Ir(III) complexes (Ir-2 and Ir-3), in which the PBI chromophore was connected to the coordination center via C≡C π-conjugation bond. The new complexes show strong absorption in visible region (ε = 34,200 M(-1) cm(-1) at 541 nm for Ir-2, and ε = 19,000 at 669 nm for Ir-3), compared to the model complex Ir(ppy)(bpy)[PF6] Ir-1 (ε PBI-localized long-lived (3)IL states were populated for Ir-2 and Ir-3 upon photoexcitation. The complexes were used as triplet photosensitizers for (1)O2-mediated photooxidation of 1,5-dihydronaphthalene to produce juglone, an important intermediate for preparation of anti-cancer compounds. (1)O2 quantum yields (Φ(Δ)) up to 91% were observed for the new Ir(III) complexes and the overall photosensitizing ability is much higher than the conventional Ir(III) complex Ir-1, which shows the typical weak visible light absorption in visible region. Our results are useful for preparation of transition metal complexes that show strong absorption of visible light and long-lived triplet excited state and for the application of these complexes in photocatalysis.

  17. HIV Incidence and Predictors of Incident HIV among Men Who Have Sex with Men Attending a Sexual Health Clinic in Melbourne, Australia.

    Directory of Open Access Journals (Sweden)

    King T Cheung

    Full Text Available The aim of this study was to determine the risk factors for HIV infection and the incidence in men who have sex with men (MSM. It is important to identify subgroups of MSM in which preventive interventions such as pre-exposure prophylaxis (PrEP offered at the time of their last negative test would be considered cost-effective.We conducted a retrospective cohort study of MSM attending Melbourne Sexual Health Centre (MSHC during 2007-2013 with at least two HIV tests within 12 months of each other. Demographic characteristics, sexual and other behaviours, and bacterial sexually transmitted infection (STI diagnoses were extracted from the date of the last negative HIV test. HIV incidence rate (IR per 100 person-years for each risk factor was calculated.Of the 13907 MSM who attended MSHC, 5256 MSM had at least two HIV tests and were eligible, contributing 6391 person-years follow-up. 81 new HIV diagnoses were identified within 12 months of an HIV negative test with an incidence of 1.3 (95% CI: 1.0-1.6 per 100 person-years. Significant associations with subsequent HIV infection were: rectal gonorrhea (HIV IR: 3.4 95% CI: 2.1-5.2, rectal chlamydia (HIV IR: 2.6 95% CI: 1.7-3.7, inconsistent condom use (HIV IR: 2.1 95% CI: 1.6-2.7, use of post-exposure prophylaxis (HIV IR: 2.3 95% CI: 1.7-3.1, and injecting drug use (HIV IR: 8.5 95% CI: 3.4-17.5.The incidence of HIV was above 2.0% in subgroups of MSM with specific characteristics at the last HIV negative test. PrEP is considered cost effective at this incidence and could potentially be used along with other preventive interventions for these individuals in more than half of the population.

  18. Physical demands in competitive ultimate frisbee

    DEFF Research Database (Denmark)

    Krustrup, Peter; Mohr, Magni

    2015-01-01

    The objective was to study game demands in competitive ultimate Frisbee by performing match analysis during a game. Thirteen moderately trained (Yo-Yo intermittent recovery test levels 1 and 2 [Yo-Yo IR1 and IR2] performance: 1790 ± 382 m and 657 ± 225 m, respectively) competitive male ultimate...... = 0.74, p ≤ 0.05). Ultimate Frisbee is an intense intermittent team sport with high cardiovascular loading and clear indications of fatigue toward the end of each half. Yo-Yo IR test performances correlate with physical match performance....

  19. Caffeine intake improves intense intermittent exercise performance and reduces muscle interstitial potassium accumulation

    DEFF Research Database (Denmark)

    Mohr, Magni; Nielsen, Jens Jung; Bangsbo, Jens

    2011-01-01

    The effect of oral caffeine ingestion on intense intermittent exercise performance and muscle interstitial ion concentrations was examined. The study consists of two studies (S1 and S2). In S1 twelve subjects completed the Yo-Yo intermittent recovery level 2 (Yo-Yo IR2) test with prior caffeine (6...... mg/kg b.w.; CAF) or placebo (PLA) intake. In S2 six subjects performed one low intense (20 W) and three intense (50 W) 3-min (separated by 5 min) one-legged knee-extension exercise bouts with (CAF) and without (CON) prior caffeine supplementation for determination of muscle interstitial K(+) and Na...

  20. Effect of additional speed endurance training on performance and muscle adaptations

    DEFF Research Database (Denmark)

    Gunnarsson, Thomas; Christensen, Peter Møller; Holse, Kris

    2012-01-01

    PURPOSE: The present study examined the effect of additional speed-endurance training during the season on muscle adaptations and performance of trained soccer players. METHODS: Eighteen sub-elite soccer players performed one session with 6-9 30-s intervals at an intensity of 90-95 % ofmaximal...... intensity (speed endurance training; SET) a week for 5 weeks (SET-intervention). Before and after the SET-intervention the players carried out the Yo-Yo intermittent recovery level 2 (Yo- Yo IR2) test, a sprint test (10- and 30-m) and an agility test. In addition, seven of the players had a resting muscle...

  1. Time Resolved X-Ray Scattering of molecules in Solution

    DEFF Research Database (Denmark)

    Brandt van Driel, Tim

    The dissertation describes the use of Time-Resolved X-ray Diffuse Scattering (TR-XDS) to study photo-induced structural changes in molecules in solution. The application of the technique is exemplified with experiments on two bimetallic molecules. The main focus is on the data-flow and process......)42+ obtained at European Synchrotron Radiation Facility (ESRF) are presented to exemplify TR-XDS at synchrotrons. Similarly, measurements on Ir2(dimen)42+ are used to show the XFEL data-flow and how it deviates from the prior. A method to identify and account for systematic fluctuations...

  2. Comparison between two types of anaerobic speed endurance training in competitive soccer players

    DEFF Research Database (Denmark)

    Mohr, Magni; Krustrup, Peter

    2016-01-01

    The purpose of the present study was to examine the effects of additional in-season speed endurance production versus speed endurance maintenance training regimes on performance in competitive male soccer players. In a randomised controlled trial 18 male sub-elite players were exposed to additional...... during training were higher (psoccer players with superior...... speed endurance production (SEP) or speed endurance maintenance (SEM) training (two additional sessions/wk for 4 weeks) during the competitive season. Players performed the Yo-Yo intermittent recovery level 2 test (YYIR2) and a repeated sprint test (RST) pre- and postintervention. Yo-Yo IR2 performance...

  3. Shock Ignition Target Design for Inertial Fusion Energy

    Science.gov (United States)

    2010-01-01

    on the Nike KrF laser (0.248µm wavelength) are consistent with an intensity limit of about a factor of two higher8,9, and further experiments are...McLean, and C. Manka, “Observations of the Two Plasmon Decay Instability Driven by the Nike KrF Laser” submitted to Physical Review Letters. 9J. L...Lehmberg, J. A. Giuliani, and A. J. Schmitt, Journal Appl . Phys. 106, 023103 (2009). 17In general, we use V 2 ≡ I0.78R/ρ∆R, T ≡ R/V , E ≡ IR2T , and ṁ

  4. Krüppel-like Factor 5, Increased in Pancreatic Ductal Adenocarcinoma, Promotes Proliferation, Acinar-to-Ductal Metaplasia, Pancreatic Intraepithelial Neoplasia, and Tumor Growth in Mice.

    Science.gov (United States)

    He, Ping; Yang, Jong Won; Yang, Vincent W; Bialkowska, Agnieszka B

    2018-04-01

    Activating mutations in KRAS are detected in most pancreatic ductal adenocarcinomas (PDACs). Expression of an activated form of KRAS (KrasG12D) in pancreata of mice is sufficient to induce formation of pancreatic intraepithelial neoplasia (PanINs)-a precursor of PDAC. Pancreatitis increases formation of PanINs in mice that express KrasG12D by promoting acinar-to-ductal metaplasia (ADM). We investigated the role of the transcription factor Krüppel-like factor 5 (KLF5) in ADM and KRAS-mediated formation of PanINs. We performed studies in adult mice with conditional disruption of Klf5 (Klf5 fl/fl ) and/or expression of Kras G12D (LSL-Kras G12D ) via Cre ERTM recombinase regulated by an acinar cell-specific promoter (Ptf1a). Activation of Kras G12D and loss of KLF5 was achieved by administration of tamoxifen. Pancreatitis was induced in mice by administration of cerulein; pancreatic tissues were collected, analyzed by histology and immunohistochemistry, and transcriptomes were compared between mice that did or did not express KLF5. We performed immunohistochemical analyses of human tissue microarrays, comparing levels of KLF5 among 96 human samples of PDAC. UN-KC-6141 cells (pancreatic cancer cells derived from Pdx1-Cre;LSL-Kras G12D mice) were incubated with inhibitors of different kinases and analyzed in proliferation assays and by immunoblots. Expression of KLF5 was knocked down with small hairpin RNAs or CRISPR/Cas9 strategies; cells were analyzed in proliferation and gene expression assays, and compared with cells expressing control vectors. Cells were subcutaneously injected into flanks of syngeneic mice and tumor growth was assessed. Of the 96 PDAC samples analyzed, 73% were positive for KLF5 (defined as nuclear staining in more than 5% of tumor cells). Pancreata from Ptf1a-Cre ERTM ;LSL-Kras G12D mice contained ADM and PanIN lesions, which contained high levels of nuclear KLF5 within these structures. In contrast, Ptf1a-Cre ERTM ;LSL-Kras G12D ;Klf5 fl

  5. Increased Serotonin Signaling Contributes to the Warburg Effect in Pancreatic Tumor Cells Under Metabolic Stress and Promotes Growth of Pancreatic Tumors in Mice.

    Science.gov (United States)

    Jiang, Shu-Heng; Li, Jun; Dong, Fang-Yuan; Yang, Jian-Yu; Liu, De-Jun; Yang, Xiao-Mei; Wang, Ya-Hui; Yang, Min-Wei; Fu, Xue-Liang; Zhang, Xiao-Xin; Li, Qing; Pang, Xiu-Feng; Huo, Yan-Miao; Li, Jiao; Zhang, Jun-Feng; Lee, Ho-Young; Lee, Su-Jae; Qin, Wen-Xin; Gu, Jian-Ren; Sun, Yong-Wei; Zhang, Zhi-Gang

    2017-07-01

    Desmoplasia and poor vascularity cause severe metabolic stress in pancreatic ductal adenocarcinomas (PDACs). Serotonin (5-HT) is a neuromodulator with neurotransmitter and neuroendocrine functions that contributes to tumorigenesis. We investigated the role of 5-HT signaling in the growth of pancreatic tumors. We measured the levels of proteins that regulate 5-HT synthesis, packaging, and degradation in pancreata from Kras G12D/+ /Trp53 R172H/+ /Pdx1-Cre (KPC) mice, which develop pancreatic tumors, as well as in PDAC cell lines and a tissue microarray containing 81 human PDAC samples. We also analyzed expression levels of proteins involved in 5-HT synthesis and degradation by immunohistochemical analysis of a tissue microarray containing 311 PDAC specimens, and associated expression levels with patient survival times. 5-HT level in 14 matched PDAC tumor and non-tumor tissues were analyzed by ELISA. PDAC cell lines were incubated with 5-HT and cell survival and apoptosis were measured. We analyzed expression of the 5-HT receptor HTR2B in PDAC cells and effects of receptor agonists and antagonists, as well as HTR2B knockdown with small hairpin RNAs. We determined the effects of 5-HT stimulation on gene expression profiles of BxPC-3 cells. Regulation of glycolysis by 5-HT signaling via HTR2B was assessed by immunofluorescence and immunoprecipitation analyses, as well as by determination of the extracellular acid ratio, glucose consumption, and lactate production. Primary PDACs, with or without exposure to SB204741 (a selective antagonist of HTR2B), were grown as xenograft tumors in mice, and SB204741 was administered to tumor-bearing KPC mice; tumor growth and metabolism were measured by imaging analyses. In immunohistochemical analysis of a tissue microarray of PDAC specimens, increased levels of TPH1 and decreased level of MAOA, which regulate 5-HT synthesis and degradation, correlated with stage and size of PDACs and shorter patient survival time. We found levels

  6. Curcumin enhances recovery of pancreatic islets from cellular stress induced inflammation and apoptosis in diabetic rats

    International Nuclear Information System (INIS)

    Rashid, Kahkashan; Sil, Parames C.

    2015-01-01

    The phytochemical, curcumin, has been reported to play many beneficial roles. However, under diabetic conditions, the detail mechanism of its beneficial action in the glucose homeostasis regulatory organ, pancreas, is poorly understood. The present study has been designed and carried out to explore the role of curcumin in the pancreatic tissue of STZ induced and cellular stress mediated diabetes in eight weeks old male Wistar rats. Diabetes was induced with a single intraperitoneal dose of STZ (65 mg/kg body weight). Post to diabetes induction, animals were treated with curcumin at a dose of 100 mg/kg body weight for eight weeks. Underlying molecular and cellular mechanism was determined using various biochemical assays, DNA fragmentation, FACS, histology, immunoblotting and ELISA. Treatment with curcumin reduced blood glucose level, increased plasma insulin and mitigated oxidative stress related markers. In vivo and in vitro experimental results revealed increased levels of proinflammatory cytokines (TNF-α, IL1-β and IFN-γ), reduced level of cellular defense proteins (Nrf-2 and HO-1) and glucose transporter (GLUT-2) along with enhanced levels of signaling molecules of ER stress dependent and independent apoptosis (cleaved Caspase-12/9/8/3) in STZ administered group. Treatment with curcumin ameliorated all the adverse changes and helps the organ back to its normal physiology. Results suggest that curcumin protects pancreatic beta-cells by attenuating inflammatory responses, and inhibiting ER/mitochondrial dependent and independent pathways of apoptosis and crosstalk between them. This uniqueness and absence of any detectable adverse effect proposes the possibility of using this molecule as an effective protector in the cellular stress mediated diabetes mellitus. - Highlights: • STZ induced cellular stress plays a vital role in pancreatic dysfunction. • Cellular stress causes inflammation, pancreatic islet cell death and diabetes. • Deregulation of Nrf-2

  7. Curcumin enhances recovery of pancreatic islets from cellular stress induced inflammation and apoptosis in diabetic rats

    Energy Technology Data Exchange (ETDEWEB)

    Rashid, Kahkashan; Sil, Parames C., E-mail: parames@jcbose.ac.in

    2015-02-01

    The phytochemical, curcumin, has been reported to play many beneficial roles. However, under diabetic conditions, the detail mechanism of its beneficial action in the glucose homeostasis regulatory organ, pancreas, is poorly understood. The present study has been designed and carried out to explore the role of curcumin in the pancreatic tissue of STZ induced and cellular stress mediated diabetes in eight weeks old male Wistar rats. Diabetes was induced with a single intraperitoneal dose of STZ (65 mg/kg body weight). Post to diabetes induction, animals were treated with curcumin at a dose of 100 mg/kg body weight for eight weeks. Underlying molecular and cellular mechanism was determined using various biochemical assays, DNA fragmentation, FACS, histology, immunoblotting and ELISA. Treatment with curcumin reduced blood glucose level, increased plasma insulin and mitigated oxidative stress related markers. In vivo and in vitro experimental results revealed increased levels of proinflammatory cytokines (TNF-α, IL1-β and IFN-γ), reduced level of cellular defense proteins (Nrf-2 and HO-1) and glucose transporter (GLUT-2) along with enhanced levels of signaling molecules of ER stress dependent and independent apoptosis (cleaved Caspase-12/9/8/3) in STZ administered group. Treatment with curcumin ameliorated all the adverse changes and helps the organ back to its normal physiology. Results suggest that curcumin protects pancreatic beta-cells by attenuating inflammatory responses, and inhibiting ER/mitochondrial dependent and independent pathways of apoptosis and crosstalk between them. This uniqueness and absence of any detectable adverse effect proposes the possibility of using this molecule as an effective protector in the cellular stress mediated diabetes mellitus. - Highlights: • STZ induced cellular stress plays a vital role in pancreatic dysfunction. • Cellular stress causes inflammation, pancreatic islet cell death and diabetes. • Deregulation of Nrf-2

  8. Effects of a Carob-Pod-Derived Sweetener on Glucose Metabolism

    Directory of Open Access Journals (Sweden)

    Carmen Lambert

    2018-02-01

    Full Text Available Background: Patients with type 2 diabetes mellitus (T2DM have a higher incidence of cardiovascular (CV events. The ingestion of high-glycemic index (GI diets, specially sweetened beverage consumption, has been associated with the development of T2DM and CV disease. Objective: We investigated the effects of the intake of a sweetened beverage, obtained from natural carbohydrates containing pinitol (PEB compared to a sucrose-enriched beverage (SEB in the context of impaired glucose tolerance (IGT and diabetes. Methods: The study was divided in three different phases: (1 a discovery phase where the plasma proteomic profile was investigated by 2-DE (two-dimensional electrophoresis followed by mass spectrometry (matrix-assisted laser desorption/ionization time-of-flight—MALDI-TOF/TOF in healthy and IGT volunteers; (2 a verification phase where the potential mechanisms behind the observed protein changes were investigated in the discovery cohort and in an additional group of T2DM volunteers; and (3 the results were validated in a proof-of-concept interventional study in an animal model of diabetic rats with complementary methodologies. Results: Six weeks of pinitol-enriched beverage (PEB intake induced a significant increase in two proteins involved in the insulin secretion pathway, insulin-like growth factor acid labile subunit (IGF1BP-ALS; 1.3-fold increase; P = 0.200 and complement C4A (1.83-fold increase; P = 0.007 in IGT subjects but not in healthy volunteers. Changes in C4A were also found in the serum samples of Zucker diabetic fatty (ZDF rats after four weeks of PEB intake compared to basal levels (P = 0.042. In addition, an increased expression of the glucose transporter-2 (GLUT2 gene was observed in the jejunum (P = 0.003 of inositol-supplemented rats when compared to sucrose supplementation. This change was correlated with the observed change in C4A (P = 0.002. Conclusions: Our results suggest that the substitution of a common sugar source

  9. HIF-1α effects on angiogenic potential in human small cell lung carcinoma

    Directory of Open Access Journals (Sweden)

    Xia Wanli

    2011-08-01

    Full Text Available Abstract Background Hypoxia-inducible factor-1 alpha (HIF-1α maybe an important regulatory factor for angiogenesis of small cell lung cancer (SCLC. Our study aimed to investigate the effect of HIF-1α on angiogenic potential of SCLC including two points: One is the effect of HIF-1α on the angiogenesis of SCLC in vivo. The other is the regulation of angiogenic genes by HIF-1α in vitro and in vivo. Methods In vivo we used an alternative method to study the effect of HIF-1a on angiogenic potential of SCLC by buliding NCI-H446 cell transplantation tumor on the chick embryo chorioallantoic membrane (CAM surface. In vitro we used microarray to screen out the angiogenic genes regulated by HIF-1a and tested their expression level in CAM transplantation tumor by RT-PCR and Western-blot analysis. Results In vivo angiogenic response surrounding the SCLC transplantation tumors in chick embryo chorioallantoic membrane (CAM was promoted after exogenous HIF-1α transduction (p In vitro the changes of angiogenic genes expression induced by HIF-1α in NCI-H446 cells were analyzed by cDNA microarray experiments. HIF-1α upregulated the expression of angiogenic genes VEGF-A, TNFAIP6, PDGFC, FN1, MMP28, MMP14 to 6.76-, 6.69-, 2.26-, 2.31-, 4.39-, 2.97- fold respectively and glycolytic genes GLUT1, GLUT2 to2.98-, 3.74- fold respectively. In addition, the expression of these angiogenic factors were also upregulated by HIF-1α in the transplantion tumors in CAM as RT-PCR and Western-blot analysis indicated. Conclusions These results indicated that HIF-1α may enhance the angiogenic potential of SCLC by regulating some angiogenic genes such as VEGF-A, MMP28 etc. Therefore, HIF-1α may be a potential target for the gene targeted therapy of SCLC.

  10. Intermittent fasting reduces body fat but exacerbates hepatic insulin resistance in young rats regardless of high protein and fat diets.

    Science.gov (United States)

    Park, Sunmin; Yoo, Kyung Min; Hyun, Joo Suk; Kang, Suna

    2017-02-01

    Intermittent fasting (IMF) is a relatively new dietary approach to weight management, although the efficacy and adverse effects have not been full elucidated and the optimal diets for IMF are unknown. We tested the hypothesis that a one-meal-per-day intermittent fasting with high fat (HF) or protein (HP) diets can modify energy, lipid, and glucose metabolism in normal young male Sprague-Dawley rats with diet-induced obesity or overweight. Male rats aged 5 weeks received either HF (40% fat) or HP (26% protein) diets ad libitum (AL) or for 3 h at the beginning of the dark cycle (IMF) for 5 weeks. Epidydimal fat pads and fat deposits in the leg and abdomen were lower with HP and IMF. Energy expenditure at the beginning of the dark cycle, especially from fat oxidation, was higher with IMF than AL, possibly due to greater activity levels. Brown fat content was higher with IMF. Serum ghrelin levels were higher in HP-IMF than other groups, and accordingly, cumulative food intake was also higher in HP-IMF than HF-IMF. HF-IMF exhibited higher area under the curve (AUC) of serum glucose at the first part (0-40 min) during oral glucose tolerance test, whereas AUC of serum insulin levels in both parts were higher in IMF and HF. During intraperitoneal insulin tolerance test, serum glucose levels were higher with IMF than AL. Consistently, hepatic insulin signaling (GLUT2, pAkt) was attenuated and PEPCK expression was higher with IMF and HF than other groups, and HOMA-IR revealed significantly impaired attenuated insulin sensitivity in the IMF groups. However, surprisingly, hepatic and skeletal muscle glycogen storage was higher in IMF groups than AL. The higher glycogen storage in the IMF groups was associated with the lower expression of glycogen phosphorylase than the AL groups. In conclusion, IMF especially with HF increased insulin resistance, possibly by attenuating hepatic insulin signaling, and lowered glycogen phosphorylase expression despite decreased fat mass in young

  11. Anti-obesogenic effects of WY14643 (PPAR-alpha agonist): Hepatic mitochondrial enhancement and suppressed lipogenic pathway in diet-induced obese mice.

    Science.gov (United States)

    Veiga, Flavia Maria Silva; Graus-Nunes, Francielle; Rachid, Tamiris Lima; Barreto, Aline Barcellos; Mandarim-de-Lacerda, Carlos Alberto; Souza-Mello, Vanessa

    2017-09-01

    Non-alcoholic fatty liver disease (NAFLD) presents with growing prevalence worldwide, though its pharmacological treatment remains to be established. This study aimed to evaluate the effects of a PPAR-alpha agonist on liver tissue structure, ultrastructure, and metabolism, focusing on gene and protein expression of de novo lipogenesis and gluconeogenesis pathways, in diet-induced obese mice. Male C57BL/6 mice (three months old) received a control diet (C, 10% of lipids, n = 10) or a high-fat diet (HFD, 50% of lipids, n = 10) for ten weeks. These groups were subdivided to receive the treatment (n = 5 per group): C, C-alpha (PPAR-alpha agonist, 2.5 mg/kg/day mixed in the control diet), HFD and HFD-alpha group (PPAR-alpha agonist, 2.5 mg/kg/day mixed in the HFD). The effects were compared with biometrical, biochemical, molecular biology and transmission electron microscopy (TEM) analyses. HFD showed greater body mass (BM) and insulinemia than C, both of which were tackled by the treatment in the HFD-alpha group. Increased hepatic protein expression of glucose-6-phosphatase, CHREBP and gene expression of PEPCK in HFD points to increased gluconeogenesis. Treatment rescued these parameters in the HFD-alpha group, eliciting a reduced hepatic glucose output, confirmed by the smaller GLUT2 expression in HFD-alpha than in HFD. Conversely, favored de novo lipogenesis was found in the HFD group by the increased expression of PPAR-gamma, and its target gene SREBP-1, FAS and GK when compared to C. The treatment yielded a marked reduction in the expression of all lipogenic factors. TEM analyses showed a greater numerical density of mitochondria per area of tissue in treated than in untreated groups, suggesting an increase in beta-oxidation and the consequent NAFLD control. PPAR-alpha activation reduced BM and treated insulin resistance (IR) and NAFLD by increasing the number of mitochondria and reducing hepatic gluconeogenesis and de novo lipogenesis protein and gene

  12. Dietary supplementation of a mixture of Lactobacillus strains enhances performance of broiler chickens raised under heat stress conditions

    Science.gov (United States)

    Faseleh Jahromi, Mohammad; Wesam Altaher, Yassir; Shokryazdan, Parisa; Ebrahimi, Roohollah; Ebrahimi, Mahdi; Idrus, Zulkifli; Tufarelli, Vincenzo; Liang, Juan Boo

    2016-07-01

    High ambient temperature is a major problem in commercial broiler production in the humid tropics because high producing broiler birds consume more feed, have higher metabolic activity, and thus higher body heat production. To evaluate the effects of two previously isolated potential probiotic strains ( Lactobacillus pentosus ITA23 and Lactobacillus acidophilus ITA44) on broilers growing under heat stress condition, a total of 192 chicks were randomly allocated into four treatment groups of 48 chickens each as follows: CL, birds fed with basal diet raised in 24 °C; PL, birds fed with basal diet plus 0.1 % probiotic mixture raised in 24 °C; CH, birds fed with basal diet raised in 35 °C; and PH, birds fed with basal diet plus 0.1 % probiotic mixture raised in 35 °C. The effects of probiotic mixture on the performance, expression of nutrient absorption genes of the small intestine, volatile fatty acids (VFA) and microbial population of cecal contents, antioxidant capacity of liver, and fatty acid composition of breast muscle were investigated. Results showed that probiotic positively affected the final body weight under both temperature conditions (PL and PH groups) compared to their respective control groups (CL and CH). Probiotic supplementation numerically improved the average daily gain (ADG) under lower temperature, but significantly improved ADG under the higher temperature ( P < 0.05) by sustaining high feed intake. Under the lower temperature environment, supplementation of the two Lactobacillus strains significantly increased the expression of the four sugar transporter genes tested (GLUT2, GLUT5, SGLT1, and SGLT4) indicating probiotic enhances the absorption of this nutrient. Similar but less pronounced effect was also observed under higher temperature (35 °C) condition. In addition, the probiotic mixture improved bacterial population of the cecal contents, by increasing beneficial bacteria and decreasing Escherichia coli population, which could be

  13. Effects of a Carob-Pod-Derived Sweetener on Glucose Metabolism

    Science.gov (United States)

    Lambert, Carmen; Cubedo, Judit; Padró, Teresa; Vilahur, Gemma; López-Bernal, Sergi; Rocha, Milagros

    2018-01-01

    Background: Patients with type 2 diabetes mellitus (T2DM) have a higher incidence of cardiovascular (CV) events. The ingestion of high-glycemic index (GI) diets, specially sweetened beverage consumption, has been associated with the development of T2DM and CV disease. Objective: We investigated the effects of the intake of a sweetened beverage, obtained from natural carbohydrates containing pinitol (PEB) compared to a sucrose-enriched beverage (SEB) in the context of impaired glucose tolerance (IGT) and diabetes. Methods: The study was divided in three different phases: (1) a discovery phase where the plasma proteomic profile was investigated by 2-DE (two-dimensional electrophoresis) followed by mass spectrometry (matrix-assisted laser desorption/ionization time-of-flight—MALDI-TOF/TOF) in healthy and IGT volunteers; (2) a verification phase where the potential mechanisms behind the observed protein changes were investigated in the discovery cohort and in an additional group of T2DM volunteers; and (3) the results were validated in a proof-of-concept interventional study in an animal model of diabetic rats with complementary methodologies. Results: Six weeks of pinitol-enriched beverage (PEB) intake induced a significant increase in two proteins involved in the insulin secretion pathway, insulin-like growth factor acid labile subunit (IGF1BP-ALS; 1.3-fold increase; P = 0.200) and complement C4A (1.83-fold increase; P = 0.007) in IGT subjects but not in healthy volunteers. Changes in C4A were also found in the serum samples of Zucker diabetic fatty (ZDF) rats after four weeks of PEB intake compared to basal levels (P = 0.042). In addition, an increased expression of the glucose transporter-2 (GLUT2) gene was observed in the jejunum (P = 0.003) of inositol-supplemented rats when compared to sucrose supplementation. This change was correlated with the observed change in C4A (P = 0.002). Conclusions: Our results suggest that the substitution of a common sugar source

  14. Assessments at multiple levels of biological organization allow for an integrative determination of physiological tolerances to turbidity in an endangered fish species.

    Science.gov (United States)

    Hasenbein, Matthias; Fangue, Nann A; Geist, Juergen; Komoroske, Lisa M; Truong, Jennifer; McPherson, Rina; Connon, Richard E

    2016-01-01

    Turbidity can influence trophic levels by altering species composition and can potentially affect fish feeding strategies and predator-prey interactions. The estuarine turbidity maximum, described as an area of increased suspended particles, phytoplankton and zooplankton, generally represents a zone with higher turbidity and enhanced food sources important for successful feeding and growth in many fish species. The delta smelt (Hypomesus transpacificus) is an endangered, pelagic fish species endemic to the San Francisco Estuary and Sacramento-San Joaquin River Delta, USA, where it is associated with turbid waters. Turbidity is known to play an important role for the completion of the species' life cycle; however, turbidity ranges in the Delta are broad, and specific requirements for this fish species are still unknown. To evaluate turbidity requirements for early life stages, late-larval delta smelt were maintained at environmentally relevant turbidity levels ranging from 5 to 250 nephelometric turbidity units (NTU) for 24 h, after which a combination of physiological endpoints (molecular biomarkers and cortisol), behavioural indices (feeding) and whole-organism measures (survival) were determined. All endpoints delivered consistent results and identified turbidities between 25 and 80 NTU as preferential. Delta smelt survival rates were highest between 12 and 80 NTU and feeding rates were highest between 25 and 80 NTU. Cortisol levels indicated minimal stress between 35 and 80 NTU and were elevated at low turbidities (5, 12 and 25 NTU). Expression of stress-related genes indicated significant responses for gst, hsp70 and glut2 in high turbidities (250 NTU), and principal component analysis on all measured genes revealed a clustering of 25, 35, 50 and 80 NTU separating the medium-turbidity treatments from low- and high-turbidity treatments. Taken together, these data demonstrate that turbidity levels that are either too low or too high affect delta

  15. Zinc transporter ZIP14 functions in hepatic zinc, iron and glucose homeostasis during the innate immune response (endotoxemia.

    Directory of Open Access Journals (Sweden)

    Tolunay Beker Aydemir

    Full Text Available ZIP14 (slc39A14 is a zinc transporter induced in response to pro-inflammatory stimuli. ZIP14 induction accompanies the reduction in serum zinc (hypozincemia of acute inflammation. ZIP14 can transport Zn(2+ and non-transferrin-bound Fe(2+ in vitro. Using a Zip14(-/- mouse model we demonstrated that ZIP14 was essential for control of phosphatase PTP1B activity and phosphorylation of c-Met during liver regeneration. In the current studies, a global screening of ZIP transporter gene expression in response to LPS-induced endotoxemia was conducted. Following LPS, Zip14 was the most highly up-regulated Zip transcript in liver, but also in white adipose tissue and muscle. Using ZIP14(-/- mice we show that ZIP14 contributes to zinc absorption from the gastrointestinal tract directly or indirectly as zinc absorption was decreased in the KOs. In contrast, Zip14(-/- mice absorbed more iron. The Zip14 KO mice did not exhibit hypozincemia following LPS, but do have hypoferremia. Livers of Zip14-/- mice had increased transcript abundance for hepcidin, divalent metal transporter-1, ferritin and transferrin receptor-1 and greater accumulation of iron. The Zip14(-/- phenotype included greater body fat, hypoglycemia and higher insulin levels, as well as increased liver glucose and greater phosphorylation of the insulin receptor and increased GLUT2, SREBP-1c and FASN expression. The Zip14 KO mice exhibited decreased circulating IL-6 with increased hepatic SOCS-3 following LPS, suggesting SOCS-3 inhibited insulin signaling which produced the hypoglycemia in this genotype. The results are consistent with ZIP14 ablation yielding abnormal labile zinc pools which lead to increased SOCS-3 production through G-coupled receptor activation and increased cAMP production as well as signaled by increased pSTAT3 via the IL-6 receptor, which inhibits IRS 1/2 phosphorylation. Our data show the role of ZIP14 in the hepatocyte is multi-functional since zinc and iron trafficking are

  16. Design and fabrication report on capsule (11M 19K for out of pile test) for irradiation testing of research reactor materials at HANARO

    Energy Technology Data Exchange (ETDEWEB)

    Kim, B.G.; Yang, S.W.; Park, S.J.; Shim, K.T.; Choo, K.N.; Oh, J.M.; Lee, B.C.; Choi, M.H.; Kim, D.J.; Kim, J.M.; Kang, S.H.; Chun, Y.B.; Kim, T.K.; Jeong, Y.H.

    2012-05-15

    As a part of the research reactor development project with a plate type fuel, the irradiation tests of graphite (Gr), beryllium (Be), and zircaloy 4 materials using the capsule have been investigating to obtain the mechanical characteristics such as an irradiation growth, hardness, swelling and tensile strength at the temperature below 100 .deg. C and the 30 MW reactor power. Then, A capsule to be able to irradiate materials(graphite, Be, zircaloy 4) under 100 .deg. C at the HANARO was designed and fabricated. After performing out of pile testing in single channel test loop by using the capsule, the final design of the capsules to be irradiated in CT and IR2 test hole of HANARO was approved, and 2 sets of capsule were fabricated. These capsules will be loaded in CT and IR2 test hole of HANARO, and be started the irradiation from the end of June, 2012. After performing the irradiation testing of 2 sets of capsule, PIE (Post Irradiation Examination) on irradiated specimens (Gr, Be, and zircaloy 4) will be carry out in IMEF (Irradiated Material Examination Facility). So, the irradiation testing will be contributed to obtain the characteristic data induced neutron irradiation on Gr, Be, and zircaloy 4. And then, it is convinced that these data will be also contributed to obtain the license for JRTR (Jordan Research and Training Reactor) and new research reactor in Korea, and export research reactors.

  17. Knockout of Vasohibin-1 Gene in Mice Results in Healthy Longevity with Reduced Expression of Insulin Receptor, Insulin Receptor Substrate 1, and Insulin Receptor Substrate 2 in Their White Adipose Tissue

    Directory of Open Access Journals (Sweden)

    Eichi Takeda

    2017-01-01

    Full Text Available Vasohibin-1 (Vash1, originally isolated as an endothelium-derived angiogenesis inhibitor, has a characteristic of promoting stress tolerance in endothelial cells (ECs. We therefore speculated that the lack of the vash1 gene would result in a short lifespan. However, to our surprise, vash1−/− mice lived significantly longer with a milder senescence phenotype than wild-type (WT mice. We sought the cause of this healthy longevity and found that vash1−/− mice exhibited mild insulin resistance along with reduced expression of the insulin receptor (insr, insulin receptor substrate 1 (irs-1, and insulin receptor substrate 2 (irs-2 in their white adipose tissue (WAT but not in their liver or skeletal muscle. The expression of vash1 dominated in the WAT among those 3 organs. Importantly, vash1−/− mice did not develop diabetes even when fed a high-fat diet. These results indicate that the expression of vash1 was required for the normal insulin sensitivity of the WAT and that the target molecules for this activity were insr, irs1, and irs2. The lack of vash1 caused mild insulin resistance without the outbreak of overt diabetes and might contribute to healthy longevity.

  18. Roles of Akt and SGK1 in the Regulation of Renal Tubular Transport

    Directory of Open Access Journals (Sweden)

    Nobuhiko Satoh

    2015-01-01

    Full Text Available A serine/threonine kinase Akt is a key mediator in various signaling pathways including regulation of renal tubular transport. In proximal tubules, Akt mediates insulin signaling via insulin receptor substrate 2 (IRS2 and stimulates sodium-bicarbonate cotransporter (NBCe1, resulting in increased sodium reabsorption. In insulin resistance, the IRS2 in kidney cortex is exceptionally preserved and may mediate the stimulatory effect of insulin on NBCe1 to cause hypertension in diabetes via sodium retention. Likewise, in distal convoluted tubules and cortical collecting ducts, insulin-induced Akt phosphorylation mediates several hormonal signals to enhance sodium-chloride cotransporter (NCC and epithelial sodium channel (ENaC activities, resulting in increased sodium reabsorption. Serum- and glucocorticoid-inducible kinase 1 (SGK1 mediates aldosterone signaling. Insulin can stimulate SGK1 to exert various effects on renal transporters. In renal cortical collecting ducts, SGK1 regulates the expression level of ENaC through inhibition of its degradation. In addition, SGK1 and Akt cooperatively regulate potassium secretion by renal outer medullary potassium channel (ROMK. Moreover, sodium-proton exchanger 3 (NHE3 in proximal tubules is possibly activated by SGK1. This review focuses on recent advances in understanding of the roles of Akt and SGK1 in the regulation of renal tubular transport.

  19. Analysis of Irradiation Holes of In-Core Region

    Energy Technology Data Exchange (ETDEWEB)

    In, Won-ho; Lee, Yong-sub; Kim, Tae-hwan; Lim, Kyoung-hwan; Ahn, Hyung-jin [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-05-15

    Test fuels and materials are irradiated in the in-core region in side of the chimney. The inner chimney is composed of In-Core and Out-Core regions. The In-Core region has 23 hexagonal vertical irradiation holes named from R01 to R20, CT, IR1 and IR2 and 8 cylindrical irradiation holes named from CAR1 to CAR4 and SOR1 to SOR4. The Out-Core region is composed of 8 cylindrical irradiation holes named from OR1 to OR8 which are installed near the inner shell of the reflector tank. HANARO is the multi-purpose research reactor which utilizes in-core irradiation holes, which is being used in various field. Over the past 7 years we have used CT 8 times, IR once, IR2 and OR3 twice, OR4 three times and OR5 ten times. These irradiation holes are used to perform an evaluation of the neutron irradiation properties and the tests were all completed and done successfully. HANARO has been used successfully, and it still will be used continuously in various fields such as nuclear in-pile tests, the production of radioisotopes, neutron transmutation doping, neutron activation analysis, neutron beam research, radiography, environmental science.

  20. Deepure Tea Improves High Fat Diet-Induced Insulin Resistance and Nonalcoholic Fatty Liver Disease

    Directory of Open Access Journals (Sweden)

    Jing-Na Deng

    2015-01-01

    Full Text Available This study was to explore the protective effects of Deepure tea against insulin resistance and hepatic steatosis and elucidate the potential underlying molecular mechanisms. C57BL/6 mice were fed with a high fat diet (HFD for 8 weeks to induce the metabolic syndrome. In the Deepure tea group, HFD mice were administrated with Deepure tea at 160 mg/kg/day by gavage for 14 days. The mice in HFD group received water in the same way over the same period. The age-matched C57BL/6 mice fed with standard chow were used as normal control. Compared to the mice in HFD group, mice that received Deepure tea showed significantly reduced plasma insulin and improved insulin sensitivity. Deepure tea increased the expression of insulin receptor substrate 2 (IRS-2, which plays an important role in hepatic insulin signaling pathway. Deepure tea also led to a decrease in hepatic fatty acid synthesis and lipid accumulation, which were mediated by the downregulation of sterol regulatory element binding protein 1c (SREBP-1c, fatty acid synthesis (FAS, and acetyl-CoA carboxylase (ACC proteins that are involved in liver lipogenesis. These results suggest that Deepure tea may be effective for protecting against insulin resistance and hepatic steatosis via modulating IRS-2 and downstream signaling SREBP-1c, FAS, and ACC.

  1. Relation with HOMA-IR and thyroid hormones in obese Turkish women with metabolic syndrome.

    Science.gov (United States)

    Topsakal, S; Yerlikaya, E; Akin, F; Kaptanoglu, B; Erürker, T

    2012-03-01

    The aim of this study was to investigate the relationship between insulin resistance and thyroid function in obese pre- and postmenopausal women with or without metabolic syndrome (MetS). 141 obese women were divided into two groups, HOMA-IRHOMA-IR>2.7, to evaluate relation with HOMA-IR and fatness, hormone and blood parameters. They were then divided into four groups as pre- and postmenopausal with or without MetS. Various fatness, hormone and blood parameters were examined. Statistically significant difference was found in weight, body mass index (BMI), waist circumference, fat%, fasting insulin, TSH, FT3, FT4, FSH, Anti-microsomal antibody (ANTIM) and triglycerides levels in HOMA-IRHOMA-IR>2.7 obese Turkish women. This study showed that age, weight, BMI, waist circumference, fat%, fasting insulin, FT3, ANTIM, FSH, LH, total cholesterol, triglycerides, HDL, HOMA-IR, systolic and diastolic blood pressure levels were related in preand post menopausal status in obese women with or without MetS. Obesity may influence the levels of thyroid hormones and increases the risk of MetS in women. Postmenopausal status with MetS is associated with an increased TSH, FT3 and FT4 levels and HOMA-IR in obese women. Strong relation was observed with MetS and TSH and FT3 levels.

  2. The Usefulness of Homeostatic Measurement Assessment-Insulin Resistance (HOMA-IR) for Detection of Glucose Intolerance in Thai Women of Reproductive Age with Polycystic Ovary Syndrome.

    Science.gov (United States)

    Wongwananuruk, Thanyarat; Rattanachaiyanont, Manee; Leerasiri, Pichai; Indhavivadhana, Suchada; Techatraisak, Kitirat; Angsuwathana, Surasak; Tanmahasamut, Prasong; Dangrat, Chongdee

    2012-01-01

    Objectives. To study the cut-off point of Homeostatic Measurement Assessment-Insulin Resistance (HOMA-IR) as a screening test for detection of glucose intolerance in Thai women with polycystic ovary syndrome (PCOS). Study Design. Cross-sectional study. Setting. Department of Obstetrics and Gynecology, Faculty of Medicine Siriraj Hospital. Subject. Two hundred and fifty Thai PCOS women who attended the Gynecologic Endocrinology Unit, during May 2007 to January 2009. Materials and Methods. The paitents were interviewed and examined for weight, height, waist circumference, and blood pressure. Venous blood samples were drawn twice, one at 12-hour fasting and the other at 2 hours after glucose loading. Results. The prevalence of glucose intolerance in Thai PCOS women was 20.0%. The mean of HOMA-IR was 3.53  ±  7.7. Area under an ROC curve for HOMA-IR for detecting glucose intolerance was 0.82. Using the cut-off value of HOMA-IR >2.0, there was sensitivity at 84.0%, specificity at 61.0%, positive predictive value at 35.0%, negative predictive value at 93.8%, and accuracy at 65.6%. Conclusion. HOMA-IR >2.0 was used for screening test for glucose intolerance in Thai PCOS women. If the result was positive, a specific test should be done to prove the diagnosis.

  3. The Usefulness of Homeostatic Measurement Assessment-Insulin Resistance (HOMA-IR for Detection of Glucose Intolerance in Thai Women of Reproductive Age with Polycystic Ovary Syndrome

    Directory of Open Access Journals (Sweden)

    Thanyarat Wongwananuruk

    2012-01-01

    Full Text Available Objectives. To study the cut-off point of Homeostatic Measurement Assessment-Insulin Resistance (HOMA-IR as a screening test for detection of glucose intolerance in Thai women with polycystic ovary syndrome (PCOS. Study Design. Cross-sectional study. Setting. Department of Obstetrics and Gynecology, Faculty of Medicine Siriraj Hospital. Subject. Two hundred and fifty Thai PCOS women who attended the Gynecologic Endocrinology Unit, during May 2007 to January 2009. Materials and Methods. The paitents were interviewed and examined for weight, height, waist circumference, and blood pressure. Venous blood samples were drawn twice, one at 12-hour fasting and the other at 2 hours after glucose loading. Results. The prevalence of glucose intolerance in Thai PCOS women was 20.0%. The mean of HOMA-IR was 3.53  ±  7.7. Area under an ROC curve for HOMA-IR for detecting glucose intolerance was 0.82. Using the cut-off value of HOMA-IR >2.0, there was sensitivity at 84.0%, specificity at 61.0%, positive predictive value at 35.0%, negative predictive value at 93.8%, and accuracy at 65.6%. Conclusion. HOMA-IR >2.0 was used for screening test for glucose intolerance in Thai PCOS women. If the result was positive, a specific test should be done to prove the diagnosis.

  4. Herpes zoster in psoriasis patients treated with tofacitinib.

    Science.gov (United States)

    Winthrop, Kevin L; Lebwohl, Mark; Cohen, Arnon D; Weinberg, Jeffrey M; Tyring, Stephen K; Rottinghaus, Scott T; Gupta, Pankaj; Ito, Kaori; Tan, Huaming; Kaur, Mandeep; Egeberg, Alexander; Mallbris, Lotus; Valdez, Hernan

    2017-08-01

    Tofacitinib is an oral Janus kinase (JAK) inhibitor. Immunomodulatory therapies can increase the risk for herpes zoster (HZ) in patients with psoriasis. To evaluate the relationship between tofacitinib use and HZ risk. We used phases 2 and 3 and long-term extension (LTE) data from the tofacitinib development program in psoriasis to calculate HZ incidence rates (IR; events per 100 patient-years); potential HZ risk factors were evaluated using Cox-proportional hazard models. One hundred thirty (3.6%) patients on tofacitinib (IR 2.55), no patients on placebo, and 2 using etanercept (IR 2.68) developed HZ. Nine patients (7%) were hospitalized, and 8 (6%) had multidermatomal HZ; no encephalitis, visceral involvement, or deaths occurred. In total, 121 (93%) patients on tofacitinib continued or resumed use after HZ. HZ risk factors included Asian descent (hazard ratio [HR] 2.92), using tofacitinib 10 mg twice daily (vs 5 mg twice daily; HR 1.72), prior use of biologics (HR 1.72), and older age (HR 1.30). Generalizability to other psoriasis populations might be limited. The effect of HZ vaccination was not studied. Tofacitinib is associated with increased HZ risk relative to placebo. Asian race, increasing age, higher dose, and prior biologic exposure are associated with heightened risk. Copyright © 2017 American Academy of Dermatology, Inc. Published by Elsevier Inc. All rights reserved.

  5. INFRARED TWO-COLOR DIAGRAMS FOR AGB STARS, POST-AGB STARS, AND PLANETARY NEBULAE

    Energy Technology Data Exchange (ETDEWEB)

    Suh, Kyung-Won, E-mail: kwsuh@chungbuk.ac.kr [Department of Astronomy and Space Science, Chungbuk National University, Cheongju-City, 362-763 (Korea, Republic of)

    2015-08-01

    We present various infrared two-color diagrams (2CDs) for asymptotic giant branch (AGB) stars, post-AGB stars, and Planetary Nebulae (PNe) and investigate possible evolutionary tracks. We use catalogs from the available literature for the sample of 4903 AGB stars (3373 O-rich; 1168 C-rich; 362 S-type), 660 post-AGB stars (326 post-AGB; 334 pre-PN), and 1510 PNe in our Galaxy. For each object in the catalog, we cross-identify the IRAS, AKARI, Midcourse Space Experiment, and 2MASS counterparts. The IR 2CDs can provide useful information about the structure and evolution of the dust envelopes as well as the central stars. To find possible evolutionary tracks from AGB stars to PNe on the 2CDs, we investigate spectral evolution of post-AGB stars by making simple but reasonable assumptions on the evolution of the central star and dust shell. We perform radiative transfer model calculations for the detached dust shells around evolving central stars in the post-AGB phase. We find that the theoretical dust shell model tracks using dust opacity functions of amorphous silicate and amorphous carbon roughly coincide with the densely populated observed points of AGB stars, post-AGB stars, and PNe on various IR 2CDs. Even though some discrepancies are inevitable, the end points of the theoretical post-AGB model tracks generally converge in the region of the observed points of PNe on most 2CDs.

  6. Molecular markers for X-ray-insensitive differentiated cells in the Inner and outer regions of the mesenchymal space in planarian Dugesia japonica.

    Science.gov (United States)

    Teramoto, Machiko; Kudome-Takamatsu, Tomomi; Nishimura, Osamu; An, Yang; Kashima, Makoto; Shibata, Norito; Agata, Kiyokazu

    2016-09-01

    Planarian's strong regenerative ability is dependent on stem cells (called neoblasts) that are X-ray-sensitive and proliferative stem cells. In addition to neoblasts, another type of X-ray-sensitive cells was newly identified by recent research. Thus, planarian's X-ray-sensitive cells can be divided into at least two populations, Type 1 and Type 2, the latter corresponding to planarian's classically defined "neoblasts". Here, we show that Type 1 cells were distributed in the outer region (OR) immediately underneath the muscle layer at all axial levels from head to tail, while the Type 2 cells were distributed in a more internal region (IR) of the mesenchymal space at the axial levels from neck to tail. To elucidate the biological significance of these two regions, we searched for genes expressed in differentiated cells that were locate close to these X-ray-sensitive cell populations in the mesenchymal space, and identified six genes mainly expressed in the OR or IR, named OR1, OR2, OR3, IR1, IR2 and IR3. The predicted amino acid sequences of these genes suggested that differentiated cells expressing OR1, OR3, IR1, or IR2 provide Type 1 and Type 2 cells with specific extracellular matrix (ECM) environments. © 2016 Japanese Society of Developmental Biologists.

  7. Association between IRS1 Gene Polymorphism and Autism Spectrum Disorder: A Pilot Case-Control Study in Korean Males

    Directory of Open Access Journals (Sweden)

    Hae Jeong Park

    2016-07-01

    Full Text Available The insulin-like growth factor (IGF pathway is thought to play an important role in brain development. Altered levels of IGFs and their signaling regulators have been shown in autism spectrum disorder (ASD patients. In this study, we investigated whether coding region single-nucleotide polymorphisms (cSNPs of the insulin receptor substrates (IRS1 and IRS2, key mediators of the IGF pathway, were associated with ASD in Korean males. Two cSNPs (rs1801123 of IRS1, and rs4773092 of IRS2 were genotyped using direct sequencing in 180 male ASD patients and 147 male control subjects. A significant association between rs1801123 of IRS1 and ASD was shown in additive (p = 0.022, odds ratio (OR = 0.66, 95% confidence interval (CI = 0.46–0.95 and dominant models (p = 0.013, OR = 0.57, 95% CI = 0.37–0.89. Allele frequency analysis also showed an association between rs1801123 and ASD (p = 0.022, OR = 0.66, 95% CI = 0.46–0.94. These results suggest that IRS1 may contribute to the susceptibility of ASD in Korean males.

  8. Induced star formation and colors of binary and interacting galaxies

    International Nuclear Information System (INIS)

    Smirnov, M.A.; Komberg, B.V.; Moskovskij Gosudarstvennyj Univ.

    1980-01-01

    The colours of 208 galaxies in pairs and groups are compared (on colour-colour diagram) with those of single galaxies of the same morphological type. Different colours of galaxies in pairs and groups can be explained if one assumes that in some of them the star formation is slowed down, while in others it is speeded up. The latter is the most conspicuous in E, SO, and Ir2 galaxies when they are accompanied by brighter spirals. The relation of abundance rate to the rate of star formation in galaxies and to the activity level of their nuclei is discussed. This relation is particularly conspicuous in the galaxies of early morphological types (E, SO, Sa) and in systems of the type Ir2 where the relative abundance of gas is significantly above the normal. It is noted that such galaxies as well as galaxies with UV excess, Seyfertlike objects, emission-line galaxies and quasars - avoid regions occupied with rich clusters and frequently occur in pairs and small groups

  9. Role of blink reflex in diagnosis of subclinical cranial neuropathy in diabetic mellitus type II.

    Science.gov (United States)

    Kazem, Shakouri S; Behzad, Davoudi

    2006-05-01

    Peripheral neuropathy (PN) is one of the late complications of diabetes mellitus. Cranial nerves III, VII, and V are among the most commonly affected in diabetic patients. Traditional electrodiagnosis (Edx) studies are a useful method for diagnosis of PN and symptomatic cranial neuropathy, and may not be useful for detecting subclinical involvement of cranial nerves. The main objective of this study is to evaluate the role of blink reflex (BR) for early diagnosis of cranial neuropathy in diabetic patients with PN. A prospective study was performed on NIDDM patients with PN. One hundred eighty-eight subjects were included in our study in which 142 acted as healthy subjects and 46 as diabetic patients. Patients were excluded with prior history of cranial nerve lesions, stroke, or any other disease with polyneuropathy or drug-induced neuropathy. Routine nerve conduction studies were performed, and only patients with PN were included in this study. Abnormalities were found in 54.4% of patients. R1, IR2, and CR2 were prolonged relative to the healthy group. Statistically there was no significant difference in R/D ratio of patients (P=0.201). Also, there was a positive correlation between R1, IR2, and CR2 latencies with duration of diabetes and severity of polyneuropathy, but not for R/D. The greatest correlation was shown in R1 latency (69.9% abnormality). BR is a noninvasive and very useful method for the evaluation and diagnosis of subclinical cranial nerve involvement in diabetic patients.

  10. Overexpression of SIRT1 in mouse forebrain impairs lipid/glucose metabolism and motor function.

    Directory of Open Access Journals (Sweden)

    Dongmei Wu

    Full Text Available SIRT1 plays crucial roles in glucose and lipid metabolism, and has various functions in different tissues including brain. The brain-specific SIRT1 knockout mice display defects in somatotropic signaling, memory and synaptic plasticity. And the female mice without SIRT1 in POMC neuron are more sensitive to diet-induced obesity. Here we created transgenic mice overexpressing SIRT1 in striatum and hippocampus under the control of CaMKIIα promoter. These mice, especially females, exhibited increased fat accumulation accompanied by significant upregulation of adipogenic genes in white adipose tissue. Glucose tolerance of the mice was also impaired with decreased Glut4 mRNA levels in muscle. Moreover, the SIRT1 overexpressing mice showed decreased energy expenditure, and concomitantly mitochondria-related genes were decreased in muscle. In addition, these mice showed unusual spontaneous physical activity pattern, decreased activity in open field and rotarod performance. Further studies de